Re: [hardknott][PATCH] gcc: Fix CVE-2021-42574

Mittal, Anuj
2021-12-31T00:29:07Z

I can't apply this.

git am says:

error: cannot convert from Y to UTF-8
fatal: could not parse patch

Thanks,

Anuj

On Wed, 2021-12-29 at 01:13 -0800, pgowda wrote:
> Upstream-Status: Backport
> [https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=004bb936d6d5f177af26ad
> 4905595e843d5665a5]
> Upstream-Status: Backport
> [https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=bd5e882cf6e0def3dd1bc1
> 06075d59a303fe0d1e]
> Upstream-Status: Backport
> [https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=51c500269bf53749b10780
> 7d84271385fad35628]
> Upstream-Status: Backport
> [https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=1a7f2c0774129750fdf73e
> 9f1b78f0ce983c9ab3]
> Upstream-Status: Backport
> [https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=bef32d4a28595e933f24fe
> f378cf052a30b674a7]
>
> Signed-off-by: pgowda <pgowda.cve@gmail.com>
> ---
>  meta/recipes-devtools/gcc/gcc-10.2.inc        |    5 +
>  .../gcc/gcc/0001-CVE-2021-42574.patch         | 2906
> +++++++++++++++++
>  .../gcc/gcc/0002-CVE-2021-42574.patch         | 2270 +++++++++++++
>  .../gcc/gcc/0003-CVE-2021-42574.patch         | 1724 ++++++++++
>  .../gcc/gcc/0004-CVE-2021-42574.patch         |  138 +
>  .../gcc/gcc/0005-CVE-2021-42574.patch         |  575 ++++
>  6 files changed, 7618 insertions(+)
>  create mode 100644 meta/recipes-devtools/gcc/gcc/0001-CVE-2021-
> 42574.patch
>  create mode 100644 meta/recipes-devtools/gcc/gcc/0002-CVE-2021-
> 42574.patch
>  create mode 100644 meta/recipes-devtools/gcc/gcc/0003-CVE-2021-
> 42574.patch
>  create mode 100644 meta/recipes-devtools/gcc/gcc/0004-CVE-2021-
> 42574.patch
>  create mode 100644 meta/recipes-devtools/gcc/gcc/0005-CVE-2021-
> 42574.patch
>
> diff --git a/meta/recipes-devtools/gcc/gcc-10.2.inc b/meta/recipes-
> devtools/gcc/gcc-10.2.inc
> index 5626bf20f0..fd7f16d7bf 100644
> --- a/meta/recipes-devtools/gcc/gcc-10.2.inc
> +++ b/meta/recipes-devtools/gcc/gcc-10.2.inc
> @@ -74,6 +74,11 @@ SRC_URI = "\
>             file://0002-CVE-2021-35465.patch \
>             file://0003-CVE-2021-35465.patch \
>             file://0004-CVE-2021-35465.patch \
> +           file://0001-CVE-2021-42574.patch \
> +           file://0002-CVE-2021-42574.patch \
> +           file://0003-CVE-2021-42574.patch \
> +           file://0004-CVE-2021-42574.patch \
> +           file://0005-CVE-2021-42574.patch \
>  "
>  SRC_URI[sha256sum] =
> "b8dd4368bb9c7f0b98188317ee0254dd8cc99d1e3a18d0ff146c855fe16c1d8c"
>
> diff --git a/meta/recipes-devtools/gcc/gcc/0001-CVE-2021-42574.patch
> b/meta/recipes-devtools/gcc/gcc/0001-CVE-2021-42574.patch
> new file mode 100644
> index 0000000000..e0f4f7d32f
> --- /dev/null
> +++ b/meta/recipes-devtools/gcc/gcc/0001-CVE-2021-42574.patch
> @@ -0,0 +1,2906 @@
> +From 004bb936d6d5f177af26ad4905595e843d5665a5 Mon Sep 17 00:00:00
> 2001
> +From: Lewis Hyatt <lhyatt@gmail.com>
> +Date: Tue, 14 Jul 2020 12:05:56 -0400
> +Subject: [PATCH] diagnostics: Support conversion of tabs to spaces
> [PR49973]
> + [PR86904]
> +
> +Supports conversion of tabs to spaces when outputting diagnostics.
> Also
> +adds -fdiagnostics-column-unit and -fdiagnostics-column-origin
> options to
> +control how the column number is output, thereby resolving the two
> PRs.
> +
> +gcc/c-family/ChangeLog:
> +
> +       PR other/86904
> +       * c-indentation.c (should_warn_for_misleading_indentation):
> Get
> +       global tabstop from the new source.
> +       * c-opts.c (c_common_handle_option): Remove handling of -
> ftabstop, which
> +       is now a common option.
> +       * c.opt: Likewise.
> +
> +gcc/ChangeLog:
> +
> +       PR preprocessor/49973
> +       PR other/86904
> +       * common.opt: Handle -ftabstop here instead of in c-family
> +       options.  Add -fdiagnostics-column-unit= and
> +       -fdiagnostics-column-origin= options.
> +       * opts.c (common_handle_option): Handle the new options.
> +       * diagnostic-format-json.cc (json_from_expanded_location):
> Add
> +       diagnostic_context argument.  Use it to convert column
> numbers as per
> +       the new options.
> +       (json_from_location_range): Likewise.
> +       (json_from_fixit_hint): Likewise.
> +       (json_end_diagnostic): Pass the new context argument to
> helper
> +       functions above.  Add "column-origin" field to the output.
> +       (test_unknown_location): Add the new context argument to
> calls to
> +       helper functions.
> +       (test_bad_endpoints): Likewise.
> +       * diagnostic-show-locus.c
> +       (exploc_with_display_col::exploc_with_display_col): Support
> +       tabstop parameter.
> +       (layout_point::layout_point): Make use of class
> +       exploc_with_display_col.
> +       (layout_range::layout_range): Likewise.
> +       (struct line_bounds): Clarify that the units are now always
> +       display columns.  Rename members accordingly.  Add
> constructor.
> +       (layout::print_source_line): Add support for tab expansion.
> +       (make_range): Adapt to class layout_range changes.
> +       (layout::maybe_add_location_range): Likewise.
> +       (layout::layout): Adapt to class exploc_with_display_col
> changes.
> +       (layout::calculate_x_offset_display): Support tabstop
> parameter.
> +       (layout::print_annotation_line): Adapt to struct line_bounds
> changes.
> +       (layout::print_line): Likewise.
> +       (line_label::line_label): Add diagnostic_context argument.
> +       (get_affected_range): Likewise.
> +       (get_printed_columns): Likewise.
> +       (layout::print_any_labels): Adapt to struct line_label
> changes.
> +       (class correction): Add m_tabstop member.
> +       (correction::correction): Add tabstop argument.
> +       (correction::compute_display_cols): Use m_tabstop.
> +       (class line_corrections): Add m_context member.
> +       (line_corrections::line_corrections): Add diagnostic_context
> argument.
> +       (line_corrections::add_hint): Use m_context to handle
> tabstops.
> +       (layout::print_trailing_fixits): Adapt to class
> line_corrections
> +       changes.
> +       (test_layout_x_offset_display_utf8): Support tabstop
> parameter.
> +       (test_layout_x_offset_display_tab): New selftest.
> +       (test_one_liner_colorized_utf8): Likewise.
> +       (test_tab_expansion): Likewise.
> +       (test_diagnostic_show_locus_one_liner_utf8): Call the new
> tests.
> +       (diagnostic_show_locus_c_tests): Likewise.
> +       (test_overlapped_fixit_printing): Adapt to helper class and
> +       function changes.
> +       (test_overlapped_fixit_printing_utf8): Likewise.
> +       (test_overlapped_fixit_printing_2): Likewise.
> +       * diagnostic.h (enum diagnostics_column_unit): New enum.
> +       (struct diagnostic_context): Add members for the new options.
> +       (diagnostic_converted_column): Declare.
> +       (json_from_expanded_location): Add new context argument.
> +       * diagnostic.c (diagnostic_initialize): Initialize new
> members.
> +       (diagnostic_converted_column): New function.
> +       (maybe_line_and_column): Be willing to output a column of 0.
> +       (diagnostic_get_location_text): Convert column number as per
> the new
> +       options.
> +       (diagnostic_report_current_module): Likewise.
> +       (assert_location_text): Add origin and column_unit arguments
> for
> +       testing the new functionality.
> +       (test_diagnostic_get_location_text): Test the new
> functionality.
> +       * doc/invoke.texi: Document the new options and behavior.
> +       * input.h (location_compute_display_column): Add tabstop
> argument.
> +       * input.c (location_compute_display_column): Likewise.
> +       (test_cpp_utf8): Add selftests for tab expansion.
> +       * tree-diagnostic-path.cc (default_tree_make_json_for_path):
> Pass the
> +       new context argument to json_from_expanded_location().
> +
> +libcpp/ChangeLog:
> +
> +       PR preprocessor/49973
> +       PR other/86904
> +       * include/cpplib.h (struct cpp_options):  Removed support for
> -ftabstop,
> +       which is now handled by diagnostic_context.
> +       (class cpp_display_width_computation): New class.
> +       (cpp_byte_column_to_display_column): Add optional tabstop
> argument.
> +       (cpp_display_width): Likewise.
> +       (cpp_display_column_to_byte_column): Likewise.
> +       * charset.c
> +       (cpp_display_width_computation::cpp_display_width_computation
> ): New
> +       function.
> +       (cpp_display_width_computation::advance_display_cols):
> Likewise.
> +       (compute_next_display_width): Removed and implemented this
> +       functionality in a new function...
> +       (cpp_display_width_computation::process_next_codepoint):
> ...here.
> +       (cpp_byte_column_to_display_column): Added tabstop argument.
> +       Reimplemented in terms of class
> cpp_display_width_computation.
> +       (cpp_display_column_to_byte_column): Likewise.
> +       * init.c (cpp_create_reader): Remove handling of -ftabstop,
> which is now
> +       handled by diagnostic_context.
> +
> +gcc/testsuite/ChangeLog:
> +
> +       PR preprocessor/49973
> +       PR other/86904
> +       * c-c++-common/Wmisleading-indentation-3.c: Adjust expected
> output
> +       for new defaults.
> +       * c-c++-common/Wmisleading-indentation.c: Likewise.
> +       * c-c++-common/diagnostic-format-json-1.c: Likewise.
> +       * c-c++-common/diagnostic-format-json-2.c: Likewise.
> +       * c-c++-common/diagnostic-format-json-3.c: Likewise.
> +       * c-c++-common/diagnostic-format-json-4.c: Likewise.
> +       * c-c++-common/diagnostic-format-json-5.c: Likewise.
> +       * c-c++-common/missing-close-symbol.c: Likewise.
> +       * g++.dg/diagnostic/bad-binary-ops.C: Likewise.
> +       * g++.dg/parse/error4.C: Likewise.
> +       * g++.old-deja/g++.brendan/crash11.C: Likewise.
> +       * g++.old-deja/g++.pt/overload2.C: Likewise.
> +       * g++.old-deja/g++.robertl/eb109.C: Likewise.
> +       * gcc.dg/analyzer/malloc-paths-9.c: Likewise.
> +       * gcc.dg/bad-binary-ops.c: Likewise.
> +       * gcc.dg/format/branch-1.c: Likewise.
> +       * gcc.dg/format/pr79210.c: Likewise.
> +       * gcc.dg/plugin/diagnostic-test-expressions-1.c: Likewise.
> +       * gcc.dg/plugin/diagnostic-test-string-literals-1.c:
> Likewise.
> +       * gcc.dg/redecl-4.c: Likewise.
> +       * gfortran.dg/diagnostic-format-json-1.F90: Likewise.
> +       * gfortran.dg/diagnostic-format-json-2.F90: Likewise.
> +       * gfortran.dg/diagnostic-format-json-3.F90: Likewise.
> +       * go.dg/arrayclear.go: Add a comment explaining why adding a
> +       comment was necessary to work around a dejagnu bug.
> +       * c-c++-common/diagnostic-units-1.c: New test.
> +       * c-c++-common/diagnostic-units-2.c: New test.
> +       * c-c++-common/diagnostic-units-3.c: New test.
> +       * c-c++-common/diagnostic-units-4.c: New test.
> +       * c-c++-common/diagnostic-units-5.c: New test.
> +       * c-c++-common/diagnostic-units-6.c: New test.
> +       * c-c++-common/diagnostic-units-7.c: New test.
> +       * c-c++-common/diagnostic-units-8.c: New test.
> +
> +CVE: CVE-2021-42574
> +Upstream-Status: Backport
> [https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=004bb936d6d5f177af26ad
> 4905595e843d5665a5]
> +Signed-off-by: Pgowda <pgowda.cve@gmail.com>
> +---
> + gcc/c-family/c-indentation.c                  |   5 +-
> + gcc/c-family/c-opts.c                         |   6 -
> + gcc/c-family/c.opt                            |   4 -
> + gcc/common.opt                                |  21 +
> + gcc/diagnostic-format-json.cc                 |  55 +-
> + gcc/diagnostic-show-locus.c                   | 504 +++++++++++++--
> ---
> + gcc/diagnostic.c                              | 113 +++-
> + gcc/diagnostic.h                              |  28 +-
> + gcc/doc/invoke.texi                           |  68 ++-
> + gcc/input.c                                   |  72 ++-
> + gcc/input.h                                   |   4 +-
> + gcc/opts.c                                    |  14 +
> + .../c-c++-common/Wmisleading-indentation-3.c  |  12 +-
> + .../c-c++-common/Wmisleading-indentation.c    |   6 +-
> + .../c-c++-common/diagnostic-format-json-1.c   |   5 +
> + .../c-c++-common/diagnostic-format-json-2.c   |   5 +
> + .../c-c++-common/diagnostic-format-json-3.c   |   5 +
> + .../c-c++-common/diagnostic-format-json-4.c   |   9 +
> + .../c-c++-common/diagnostic-format-json-5.c   |   9 +
> + .../c-c++-common/diagnostic-units-1.c         |  28 +
> + .../c-c++-common/diagnostic-units-2.c         |  28 +
> + .../c-c++-common/diagnostic-units-3.c         |  28 +
> + .../c-c++-common/diagnostic-units-4.c         |  28 +
> + .../c-c++-common/diagnostic-units-5.c         |  28 +
> + .../c-c++-common/diagnostic-units-6.c         |  28 +
> + .../c-c++-common/diagnostic-units-7.c         |  28 +
> + .../c-c++-common/diagnostic-units-8.c         |  28 +
> + .../c-c++-common/missing-close-symbol.c       |   6 +-
> + .../g++.dg/diagnostic/bad-binary-ops.C        |   8 +-
> + gcc/testsuite/g++.dg/parse/error4.C           |   2 +-
> + .../g++.old-deja/g++.brendan/crash11.C        |   4 +-
> + gcc/testsuite/g++.old-deja/g++.pt/overload2.C |   2 +-
> + .../g++.old-deja/g++.robertl/eb109.C          |   4 +-
> + .../gcc.dg/analyzer/malloc-paths-9.c          |   2 +-
> + gcc/testsuite/gcc.dg/bad-binary-ops.c         |   8 +-
> + gcc/testsuite/gcc.dg/format/branch-1.c        |   2 +-
> + gcc/testsuite/gcc.dg/format/pr79210.c         |   2 +-
> + .../plugin/diagnostic-test-expressions-1.c    |  16 +-
> + .../diagnostic-test-string-literals-1.c       |   4 +-
> + gcc/testsuite/gcc.dg/redecl-4.c               |   2 +-
> + .../gfortran.dg/diagnostic-format-json-1.F90  |   5 +
> + .../gfortran.dg/diagnostic-format-json-2.F90  |   5 +
> + .../gfortran.dg/diagnostic-format-json-3.F90  |   5 +
> + gcc/testsuite/go.dg/arrayclear.go             |   3 +
> + gcc/tree-diagnostic-path.cc                   |   5 +-
> + libcpp/charset.c                              |  98 ++--
> + libcpp/include/cpplib.h                       |  40 +-
> + libcpp/init.c                                 |   1 -
> + 48 files changed, 1106 insertions(+), 287 deletions(-)
> + create mode 100644 gcc/testsuite/c-c++-common/diagnostic-units-1.c
> + create mode 100644 gcc/testsuite/c-c++-common/diagnostic-units-2.c
> + create mode 100644 gcc/testsuite/c-c++-common/diagnostic-units-3.c
> + create mode 100644 gcc/testsuite/c-c++-common/diagnostic-units-4.c
> + create mode 100644 gcc/testsuite/c-c++-common/diagnostic-units-5.c
> + create mode 100644 gcc/testsuite/c-c++-common/diagnostic-units-6.c
> + create mode 100644 gcc/testsuite/c-c++-common/diagnostic-units-7.c
> + create mode 100644 gcc/testsuite/c-c++-common/diagnostic-units-8.c
> +
> +diff --git a/gcc/c-family/c-indentation.c b/gcc/c-family/c-
> indentation.c
> +--- a/gcc/c-family/c-indentation.c     2020-07-22 23:35:17.296384022
> -0700
> ++++ b/gcc/c-family/c-indentation.c     2021-12-25 01:20:53.475636694
> -0800
> +@@ -24,8 +24,7 @@ along with GCC; see the file COPYING3.
> + #include "c-common.h"
> + #include "c-indentation.h"
> + #include "selftest.h"
> +-
> +-extern cpp_options *cpp_opts;
> ++#include "diagnostic.h"
> +
> + /* Round up VIS_COLUMN to nearest tab stop. */
> +
> +@@ -294,7 +293,7 @@ should_warn_for_misleading_indentation (
> +   expanded_location next_stmt_exploc = expand_location
> (next_stmt_loc);
> +   expanded_location guard_exploc = expand_location (guard_loc);
> +
> +-  const unsigned int tab_width = cpp_opts->tabstop;
> ++  const unsigned int tab_width = global_dc->tabstop;
> +
> +   /* They must be in the same file.  */
> +   if (next_stmt_exploc.file != body_exploc.file)
> +diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
> +--- a/gcc/c-family/c.opt       2021-12-24 20:23:42.816809230 -0800
> ++++ b/gcc/c-family/c.opt       2021-12-25 01:20:53.475636694 -0800
> +@@ -1876,10 +1876,6 @@ Enum(strong_eval_order) String(some) Val
> + EnumValue
> + Enum(strong_eval_order) String(all) Value(2)
> +
> +-ftabstop=
> +-C ObjC C++ ObjC++ Joined RejectNegative UInteger
> +--ftabstop=<number>    Distance between tab stops for column
> reporting.
> +-
> + ftemplate-backtrace-limit=
> + C++ ObjC++ Joined RejectNegative UInteger
> Var(template_backtrace_limit) Init(10)
> + Set the maximum number of template instantiation notes for a single
> warning or error.
> +diff --git a/gcc/c-family/c-opts.c b/gcc/c-family/c-opts.c
> +--- a/gcc/c-family/c-opts.c    2021-12-24 20:23:44.824774786 -0800
> ++++ b/gcc/c-family/c-opts.c    2021-12-25 01:20:53.475636694 -0800
> +@@ -504,12 +504,6 @@ c_common_handle_option (size_t scode, co
> +       cpp_opts->track_macro_expansion = 2;
> +       break;
> +
> +-    case OPT_ftabstop_:
> +-      /* It is documented that we silently ignore silly values.  */
> +-      if (value >= 1 && value <= 100)
> +-      cpp_opts->tabstop = value;
> +-      break;
> +-
> +     case OPT_fexec_charset_:
> +       cpp_opts->narrow_charset = arg;
> +       break;
> +diff --git a/gcc/common.opt b/gcc/common.opt
> +--- a/gcc/common.opt   2021-12-24 20:23:42.480814993 -0800
> ++++ b/gcc/common.opt   2021-12-25 01:20:53.475636694 -0800
> +@@ -1325,6 +1325,14 @@ Enum(diagnostic_url_rule) String(always)
> + EnumValue
> + Enum(diagnostic_url_rule) String(auto) Value(DIAGNOSTICS_URL_AUTO)
> +
> ++fdiagnostics-column-unit=
> ++Common Joined RejectNegative Enum(diagnostics_column_unit)
> ++-fdiagnostics-column-unit=[display|byte]      Select whether column
> numbers are output as display columns (default) or raw bytes.
> ++
> ++fdiagnostics-column-origin=
> ++Common Joined RejectNegative UInteger
> ++-fdiagnostics-column-origin=<number>  Set the number of the first
> column.  The default is 1-based as per GNU style, but some utilities
> may expect 0-based, for example.
> ++
> + fdiagnostics-format=
> + Common Joined RejectNegative Enum(diagnostics_output_format)
> + -fdiagnostics-format=[text|json]      Select output format.
> +@@ -1334,6 +1342,15 @@ SourceInclude
> + diagnostic.h
> +
> + Enum
> ++Name(diagnostics_column_unit) Type(int)
> ++
> ++EnumValue
> ++Enum(diagnostics_column_unit) String(display)
> Value(DIAGNOSTICS_COLUMN_UNIT_DISPLAY)
> ++
> ++EnumValue
> ++Enum(diagnostics_column_unit) String(byte)
> Value(DIAGNOSTICS_COLUMN_UNIT_BYTE)
> ++
> ++Enum
> + Name(diagnostics_output_format) Type(int)
> +
> + EnumValue
> +@@ -1362,6 +1379,10 @@ fdiagnostics-path-format=
> + Common Joined RejectNegative Var(flag_diagnostics_path_format)
> Enum(diagnostic_path_format) Init(DPF_INLINE_EVENTS)
> + Specify how to print any control-flow path associated with a
> diagnostic.
> +
> ++ftabstop=
> ++Common Joined RejectNegative UInteger
> ++-ftabstop=<number>      Distance between tab stops for column
> reporting.
> ++
> + Enum
> + Name(diagnostic_path_format) Type(int)
> +
> +diff --git a/gcc/diagnostic.c b/gcc/diagnostic.c
> +--- a/gcc/diagnostic.c 2020-07-22 23:35:17.556386887 -0700
> ++++ b/gcc/diagnostic.c 2021-12-25 01:23:41.300841207 -0800
> +@@ -38,6 +38,7 @@ along with GCC; see the file COPYING3.
> + #include "selftest.h"
> + #include "selftest-diagnostic.h"
> + #include "opts.h"
> ++#include "cpplib.h"
> +
> + #ifdef HAVE_TERMIOS_H
> + # include <termios.h>
> +@@ -219,6 +220,9 @@ diagnostic_initialize (diagnostic_contex
> +   context->min_margin_width = 0;
> +   context->show_ruler_p = false;
> +   context->parseable_fixits_p = false;
> ++  context->column_unit = DIAGNOSTICS_COLUMN_UNIT_DISPLAY;
> ++  context->column_origin = 1;
> ++  context->tabstop = 8;
> +   context->edit_context_ptr = NULL;
> +   context->diagnostic_group_nesting_depth = 0;
> +   context->diagnostic_group_emission_count = 0;
> +@@ -353,8 +357,51 @@ diagnostic_get_color_for_kind (diagnosti
> +   return diagnostic_kind_color[kind];
> + }
> +
> ++/* Given an expanded_location, convert the column (which is in 1-
> based bytes)
> ++   to the requested units, without converting the origin.
> ++   Return -1 if the column is invalid (<= 0).  */
> ++
> ++static int
> ++convert_column_unit (enum diagnostics_column_unit column_unit,
> ++                   int tabstop,
> ++                   expanded_location s)
> ++{
> ++  if (s.column <= 0)
> ++    return -1;
> ++
> ++  switch (column_unit)
> ++    {
> ++    default:
> ++      gcc_unreachable ();
> ++
> ++    case DIAGNOSTICS_COLUMN_UNIT_DISPLAY:
> ++      {
> ++      cpp_char_column_policy policy (tabstop, cpp_wcwidth);
> ++      return location_compute_display_column (s, policy);
> ++      }
> ++
> ++    case DIAGNOSTICS_COLUMN_UNIT_BYTE:
> ++      return s.column;
> ++    }
> ++}
> ++
> ++/* Given an expanded_location, convert the column (which is in 1-
> based bytes)
> ++   to the requested units and origin.  Return -1 if the column is
> ++   invalid (<= 0).  */
> ++int
> ++diagnostic_converted_column (diagnostic_context *context,
> expanded_location s)
> ++{
> ++  int one_based_col
> ++    = convert_column_unit (context->column_unit, context->tabstop,
> s);
> ++  if (one_based_col <= 0)
> ++    return -1;
> ++  return one_based_col + (context->column_origin - 1);
> ++}
> ++
> + /* Return a formatted line and column ':%line:%column'.  Elided if
> +-   zero.  The result is a statically allocated buffer.  */
> ++   line == 0 or col < 0.  (A column of 0 may be valid due to the
> ++   -fdiagnostics-column-origin option.)
> ++   The result is a statically allocated buffer.  */
> +
> + static const char *
> + maybe_line_and_column (int line, int col)
> +@@ -363,8 +410,9 @@ maybe_line_and_column (int line, int col
> +
> +   if (line)
> +     {
> +-      size_t l = snprintf (result, sizeof (result),
> +-                         col ? ":%d:%d" : ":%d", line, col);
> ++      size_t l
> ++      = snprintf (result, sizeof (result),
> ++                  col >= 0 ? ":%d:%d" : ":%d", line, col);
> +       gcc_checking_assert (l < sizeof (result));
> +     }
> +   else
> +@@ -383,8 +431,14 @@ diagnostic_get_location_text (diagnostic
> +   const char *locus_cs = colorize_start (pp_show_color (pp),
> "locus");
> +   const char *locus_ce = colorize_stop (pp_show_color (pp));
> +   const char *file = s.file ? s.file : progname;
> +-  int line = strcmp (file, N_("<built-in>")) ? s.line : 0;
> +-  int col = context->show_column ? s.column : 0;
> ++  int line = 0;
> ++  int col = -1;
> ++  if (strcmp (file, N_("<built-in>")))
> ++    {
> ++      line = s.line;
> ++      if (context->show_column)
> ++      col = diagnostic_converted_column (context, s);
> ++    }
> +
> +   const char *line_col = maybe_line_and_column (line, col);
> +   return build_message_string ("%s%s%s:%s", locus_cs, file,
> +@@ -650,14 +704,20 @@ diagnostic_report_current_module (diagno
> +       if (! MAIN_FILE_P (map))
> +       {
> +         bool first = true;
> ++        expanded_location s = {};
> +         do
> +           {
> +             where = linemap_included_from (map);
> +             map = linemap_included_from_linemap (line_table, map);
> +-            const char *line_col
> +-              = maybe_line_and_column (SOURCE_LINE (map, where),
> +-                                       first && context-
> >show_column
> +-                                       ? SOURCE_COLUMN (map, where)
> : 0);
> ++            s.file = LINEMAP_FILE (map);
> ++            s.line = SOURCE_LINE (map, where);
> ++            int col = -1;
> ++            if (first && context->show_column)
> ++              {
> ++                s.column = SOURCE_COLUMN (map, where);
> ++                col = diagnostic_converted_column (context, s);
> ++              }
> ++            const char *line_col = maybe_line_and_column (s.line,
> col);
> +             static const char *const msgs[] =
> +               {
> +                N_("In file included from"),
> +@@ -666,7 +726,7 @@ diagnostic_report_current_module (diagno
> +             unsigned index = !first;
> +             pp_verbatim (context->printer, "%s%s %r%s%s%R",
> +                          first ? "" : ",\n", _(msgs[index]),
> +-                         "locus", LINEMAP_FILE (map), line_col);
> ++                         "locus", s.file, line_col);
> +             first = false;
> +           }
> +         while (! MAIN_FILE_P (map));
> +@@ -2042,10 +2102,15 @@ test_print_parseable_fixits_replace ()
> + static void
> + assert_location_text (const char *expected_loc_text,
> +                     const char *filename, int line, int column,
> +-                    bool show_column)
> ++                    bool show_column,
> ++                    int origin = 1,
> ++                    enum diagnostics_column_unit column_unit
> ++                      = DIAGNOSTICS_COLUMN_UNIT_BYTE)
> + {
> +   test_diagnostic_context dc;
> +   dc.show_column = show_column;
> ++  dc.column_unit = column_unit;
> ++  dc.column_origin = origin;
> +
> +   expanded_location xloc;
> +   xloc.file = filename;
> +@@ -2069,7 +2134,10 @@ test_diagnostic_get_location_text ()
> +   assert_location_text ("PROGNAME:", NULL, 0, 0, true);
> +   assert_location_text ("<built-in>:", "<built-in>", 42, 10, true);
> +   assert_location_text ("foo.c:42:10:", "foo.c", 42, 10, true);
> +-  assert_location_text ("foo.c:42:", "foo.c", 42, 0, true);
> ++  assert_location_text ("foo.c:42:9:", "foo.c", 42, 10, true, 0);
> ++  assert_location_text ("foo.c:42:1010:", "foo.c", 42, 10, true,
> 1001);
> ++  for (int origin = 0; origin != 2; ++origin)
> ++    assert_location_text ("foo.c:42:", "foo.c", 42, 0, true,
> origin);
> +   assert_location_text ("foo.c:", "foo.c", 0, 10, true);
> +   assert_location_text ("foo.c:42:", "foo.c", 42, 10, false);
> +   assert_location_text ("foo.c:", "foo.c", 0, 10, false);
> +@@ -2077,6 +2145,41 @@ test_diagnostic_get_location_text ()
> +   maybe_line_and_column (INT_MAX, INT_MAX);
> +   maybe_line_and_column (INT_MIN, INT_MIN);
> +
> ++  {
> ++    /* In order to test display columns vs byte columns, we need to
> create a
> ++       file for location_get_source_line() to read.  */
> ++
> ++    const char *const content = "smile \xf0\x9f\x98\x82\n";
> ++    const int line_bytes = strlen (content) - 1;
> ++    const int def_tabstop = 8;
> ++    const int display_width = cpp_display_width (content,
> line_bytes,
> ++                                               def_tabstop);
> ++    ASSERT_EQ (line_bytes - 2, display_width);
> ++    temp_source_file tmp (SELFTEST_LOCATION, ".c", content);
> ++    const char *const fname = tmp.get_filename ();
> ++    const int buf_len = strlen (fname) + 16;
> ++    char *const expected = XNEWVEC (char, buf_len);
> ++
> ++    snprintf (expected, buf_len, "%s:1:%d:", fname, line_bytes);
> ++    assert_location_text (expected, fname, 1, line_bytes, true,
> ++                        1, DIAGNOSTICS_COLUMN_UNIT_BYTE);
> ++
> ++    snprintf (expected, buf_len, "%s:1:%d:", fname, line_bytes -
> 1);
> ++    assert_location_text (expected, fname, 1, line_bytes, true,
> ++                        0, DIAGNOSTICS_COLUMN_UNIT_BYTE);
> ++
> ++    snprintf (expected, buf_len, "%s:1:%d:", fname, display_width);
> ++    assert_location_text (expected, fname, 1, line_bytes, true,
> ++                        1, DIAGNOSTICS_COLUMN_UNIT_DISPLAY);
> ++
> ++    snprintf (expected, buf_len, "%s:1:%d:", fname, display_width -
> 1);
> ++    assert_location_text (expected, fname, 1, line_bytes, true,
> ++                        0, DIAGNOSTICS_COLUMN_UNIT_DISPLAY);
> ++
> ++    XDELETEVEC (expected);
> ++  }
> ++
> ++
> +   progname = old_progname;
> + }
> +
> +diff --git a/gcc/diagnostic-format-json.cc b/gcc/diagnostic-format-
> json.cc
> +--- a/gcc/diagnostic-format-json.cc    2020-07-22 23:35:17.556386887
> -0700
> ++++ b/gcc/diagnostic-format-json.cc    2021-12-25 01:20:53.475636694
> -0800
> +@@ -23,6 +23,7 @@ along with GCC; see the file COPYING3.
> + #include "system.h"
> + #include "coretypes.h"
> + #include "diagnostic.h"
> ++#include "selftest-diagnostic.h"
> + #include "diagnostic-metadata.h"
> + #include "json.h"
> + #include "selftest.h"
> +@@ -43,21 +44,43 @@ static json::array *cur_children_array;
> + /* Generate a JSON object for LOC.  */
> +
> + json::value *
> +-json_from_expanded_location (location_t loc)
> ++json_from_expanded_location (diagnostic_context *context,
> location_t loc)
> + {
> +   expanded_location exploc = expand_location (loc);
> +   json::object *result = new json::object ();
> +   if (exploc.file)
> +     result->set ("file", new json::string (exploc.file));
> +   result->set ("line", new json::integer_number (exploc.line));
> +-  result->set ("column", new json::integer_number (exploc.column));
> ++
> ++  const enum diagnostics_column_unit orig_unit = context-
> >column_unit;
> ++  struct
> ++  {
> ++    const char *name;
> ++    enum diagnostics_column_unit unit;
> ++  } column_fields[] = {
> ++    {"display-column", DIAGNOSTICS_COLUMN_UNIT_DISPLAY},
> ++    {"byte-column", DIAGNOSTICS_COLUMN_UNIT_BYTE}
> ++  };
> ++  int the_column = INT_MIN;
> ++  for (int i = 0; i != sizeof column_fields / sizeof
> (*column_fields); ++i)
> ++    {
> ++      context->column_unit = column_fields[i].unit;
> ++      const int col = diagnostic_converted_column (context,
> exploc);
> ++      result->set (column_fields[i].name, new json::integer_number
> (col));
> ++      if (column_fields[i].unit == orig_unit)
> ++      the_column = col;
> ++    }
> ++  gcc_assert (the_column != INT_MIN);
> ++  result->set ("column", new json::integer_number (the_column));
> ++  context->column_unit = orig_unit;
> +   return result;
> + }
> +
> + /* Generate a JSON object for LOC_RANGE.  */
> +
> + static json::object *
> +-json_from_location_range (const location_range *loc_range, unsigned
> range_idx)
> ++json_from_location_range (diagnostic_context *context,
> ++                        const location_range *loc_range, unsigned
> range_idx)
> + {
> +   location_t caret_loc = get_pure_location (loc_range->m_loc);
> +
> +@@ -68,13 +91,13 @@ json_from_location_range (const location
> +   location_t finish_loc = get_finish (loc_range->m_loc);
> +
> +   json::object *result = new json::object ();
> +-  result->set ("caret", json_from_expanded_location (caret_loc));
> ++  result->set ("caret", json_from_expanded_location (context,
> caret_loc));
> +   if (start_loc != caret_loc
> +       && start_loc != UNKNOWN_LOCATION)
> +-    result->set ("start", json_from_expanded_location (start_loc));
> ++    result->set ("start", json_from_expanded_location (context,
> start_loc));
> +   if (finish_loc != caret_loc
> +       && finish_loc != UNKNOWN_LOCATION)
> +-    result->set ("finish", json_from_expanded_location
> (finish_loc));
> ++    result->set ("finish", json_from_expanded_location (context,
> finish_loc));
> +
> +   if (loc_range->m_label)
> +     {
> +@@ -91,14 +114,14 @@ json_from_location_range (const location
> + /* Generate a JSON object for HINT.  */
> +
> + static json::object *
> +-json_from_fixit_hint (const fixit_hint *hint)
> ++json_from_fixit_hint (diagnostic_context *context, const fixit_hint
> *hint)
> + {
> +   json::object *fixit_obj = new json::object ();
> +
> +   location_t start_loc = hint->get_start_loc ();
> +-  fixit_obj->set ("start", json_from_expanded_location
> (start_loc));
> ++  fixit_obj->set ("start", json_from_expanded_location (context,
> start_loc));
> +   location_t next_loc = hint->get_next_loc ();
> +-  fixit_obj->set ("next", json_from_expanded_location (next_loc));
> ++  fixit_obj->set ("next", json_from_expanded_location (context,
> next_loc));
> +   fixit_obj->set ("string", new json::string (hint->get_string
> ()));
> +
> +   return fixit_obj;
> +@@ -190,11 +213,13 @@ json_end_diagnostic (diagnostic_context
> +   else
> +     {
> +       /* Otherwise, make diag_obj be the top-level object within
> the group;
> +-       add a "children" array.  */
> ++       add a "children" array and record the column origin.  */
> +       toplevel_array->append (diag_obj);
> +       cur_group = diag_obj;
> +       cur_children_array = new json::array ();
> +       diag_obj->set ("children", cur_children_array);
> ++      diag_obj->set ("column-origin",
> ++                   new json::integer_number (context-
> >column_origin));
> +     }
> +
> +   const rich_location *richloc = diagnostic->richloc;
> +@@ -205,7 +230,7 @@ json_end_diagnostic (diagnostic_context
> +   for (unsigned int i = 0; i < richloc->get_num_locations (); i++)
> +     {
> +       const location_range *loc_range = richloc->get_range (i);
> +-      json::object *loc_obj = json_from_location_range (loc_range,
> i);
> ++      json::object *loc_obj = json_from_location_range (context,
> loc_range, i);
> +       if (loc_obj)
> +       loc_array->append (loc_obj);
> +     }
> +@@ -217,7 +242,7 @@ json_end_diagnostic (diagnostic_context
> +       for (unsigned int i = 0; i < richloc->get_num_fixit_hints ();
> i++)
> +       {
> +         const fixit_hint *hint = richloc->get_fixit_hint (i);
> +-        json::object *fixit_obj = json_from_fixit_hint (hint);
> ++        json::object *fixit_obj = json_from_fixit_hint (context,
> hint);
> +         fixit_array->append (fixit_obj);
> +       }
> +     }
> +@@ -320,7 +345,8 @@ namespace selftest {
> + static void
> + test_unknown_location ()
> + {
> +-  delete json_from_expanded_location (UNKNOWN_LOCATION);
> ++  test_diagnostic_context dc;
> ++  delete json_from_expanded_location (&dc, UNKNOWN_LOCATION);
> + }
> +
> + /* Verify that we gracefully handle attempts to serialize bad
> +@@ -338,7 +364,8 @@ test_bad_endpoints ()
> +   loc_range.m_range_display_kind = SHOW_RANGE_WITH_CARET;
> +   loc_range.m_label = NULL;
> +
> +-  json::object *obj = json_from_location_range (&loc_range, 0);
> ++  test_diagnostic_context dc;
> ++  json::object *obj = json_from_location_range (&dc, &loc_range,
> 0);
> +   /* We should have a "caret" value, but no "start" or "finish"
> values.  */
> +   ASSERT_TRUE (obj != NULL);
> +   ASSERT_TRUE (obj->get ("caret") != NULL);
> +diff --git a/gcc/diagnostic.h b/gcc/diagnostic.h
> +--- a/gcc/diagnostic.h 2020-07-22 23:35:17.556386887 -0700
> ++++ b/gcc/diagnostic.h 2021-12-25 01:20:53.479636627 -0800
> +@@ -24,6 +24,20 @@ along with GCC; see the file COPYING3.
> + #include "pretty-print.h"
> + #include "diagnostic-core.h"
> +
> ++/* An enum for controlling what units to use for the column number
> ++   when diagnostics are output, used by the -fdiagnostics-column-
> unit option.
> ++   Tabs will be expanded or not according to the value of -
> ftabstop.  The origin
> ++   (default 1) is controlled by -fdiagnostics-column-origin.  */
> ++
> ++enum diagnostics_column_unit
> ++{
> ++  /* The default from GCC 11 onwards: display columns.  */
> ++  DIAGNOSTICS_COLUMN_UNIT_DISPLAY,
> ++
> ++  /* The behavior in GCC 10 and earlier: simple bytes.  */
> ++  DIAGNOSTICS_COLUMN_UNIT_BYTE
> ++};
> ++
> + /* Enum for overriding the standard output format.  */
> +
> + enum diagnostics_output_format
> +@@ -280,6 +294,15 @@ struct diagnostic_context
> +      rest of the diagnostic.  */
> +   bool parseable_fixits_p;
> +
> ++  /* What units to use when outputting the column number.  */
> ++  enum diagnostics_column_unit column_unit;
> ++
> ++  /* The origin for the column number (1-based or 0-based
> typically).  */
> ++  int column_origin;
> ++
> ++  /* The size of the tabstop for tab expansion.  */
> ++  int tabstop;
> ++
> +   /* If non-NULL, an edit_context to which fix-it hints should be
> +      applied, for generating patches.  */
> +   edit_context *edit_context_ptr;
> +@@ -458,6 +481,8 @@ diagnostic_same_line (const diagnostic_c
> + }
> +
> + extern const char *diagnostic_get_color_for_kind (diagnostic_t
> kind);
> ++extern int diagnostic_converted_column (diagnostic_context
> *context,
> ++                                      expanded_location s);
> +
> + /* Pure text formatting support functions.  */
> + extern char *file_name_as_prefix (diagnostic_context *, const char
> *);
> +@@ -470,6 +495,7 @@ extern void diagnostic_output_format_ini
> + /* Compute the number of digits in the decimal representation of an
> integer.  */
> + extern int num_digits (int);
> +
> +-extern json::value *json_from_expanded_location (location_t loc);
> ++extern json::value *json_from_expanded_location (diagnostic_context
> *context,
> ++                                               location_t loc);
> +
> + #endif /* ! GCC_DIAGNOSTIC_H */
> +diff --git a/gcc/diagnostic-show-locus.c b/gcc/diagnostic-show-
> locus.c
> +--- a/gcc/diagnostic-show-locus.c      2020-07-22 23:35:17.556386887
> -0700
> ++++ b/gcc/diagnostic-show-locus.c      2021-12-25 01:20:53.479636627
> -0800
> +@@ -175,9 +175,10 @@ enum column_unit {
> + class exploc_with_display_col : public expanded_location
> + {
> +  public:
> +-  exploc_with_display_col (const expanded_location &exploc)
> ++  exploc_with_display_col (const expanded_location &exploc, int
> tabstop)
> +     : expanded_location (exploc),
> +-      m_display_col (location_compute_display_column (exploc)) {}
> ++      m_display_col (location_compute_display_column (exploc,
> tabstop))
> ++  {}
> +
> +   int m_display_col;
> + };
> +@@ -189,11 +190,11 @@ class exploc_with_display_col : public e
> + class layout_point
> + {
> +  public:
> +-  layout_point (const expanded_location &exploc)
> ++  layout_point (const exploc_with_display_col &exploc)
> +     : m_line (exploc.line)
> +   {
> +     m_columns[CU_BYTES] = exploc.column;
> +-    m_columns[CU_DISPLAY_COLS] = location_compute_display_column
> (exploc);
> ++    m_columns[CU_DISPLAY_COLS] = exploc.m_display_col;
> +   }
> +
> +   linenum_type m_line;
> +@@ -205,10 +206,10 @@ class layout_point
> + class layout_range
> + {
> +  public:
> +-  layout_range (const expanded_location *start_exploc,
> +-              const expanded_location *finish_exploc,
> ++  layout_range (const exploc_with_display_col &start_exploc,
> ++              const exploc_with_display_col &finish_exploc,
> +               enum range_display_kind range_display_kind,
> +-              const expanded_location *caret_exploc,
> ++              const exploc_with_display_col &caret_exploc,
> +               unsigned original_idx,
> +               const range_label *label);
> +
> +@@ -226,22 +227,18 @@ class layout_range
> +
> + /* A struct for use by layout::print_source_line for telling
> +    layout::print_annotation_line the extents of the source line
> that
> +-   it printed, so that underlines can be clipped appropriately.  */
> ++   it printed, so that underlines can be clipped appropriately.
> Units
> ++   are 1-based display columns.  */
> +
> + struct line_bounds
> + {
> +-  int m_first_non_ws;
> +-  int m_last_non_ws;
> ++  int m_first_non_ws_disp_col;
> ++  int m_last_non_ws_disp_col;
> +
> +-  void convert_to_display_cols (char_span line)
> ++  line_bounds ()
> +   {
> +-    m_first_non_ws = cpp_byte_column_to_display_column
> (line.get_buffer (),
> +-                                                      line.length
> (),
> +-
>                                                       m_first_non_ws)
> ;
> +-
> +-    m_last_non_ws = cpp_byte_column_to_display_column
> (line.get_buffer (),
> +-                                                     line.length
> (),
> +-
> m_last_non_ws);
> ++    m_first_non_ws_disp_col = INT_MAX;
> ++    m_last_non_ws_disp_col = 0;
> +   }
> + };
> +
> +@@ -351,8 +348,8 @@ class layout
> +  private:
> +   bool will_show_line_p (linenum_type row) const;
> +   void print_leading_fixits (linenum_type row);
> +-  void print_source_line (linenum_type row, const char *line, int
> line_bytes,
> +-                        line_bounds *lbounds_out);
> ++  line_bounds print_source_line (linenum_type row, const char
> *line,
> ++                               int line_bytes);
> +   bool should_print_annotation_line_p (linenum_type row) const;
> +   void start_annotation_line (char margin_char = ' ') const;
> +   void print_annotation_line (linenum_type row, const line_bounds
> lbounds);
> +@@ -513,16 +510,16 @@ colorizer::get_color_by_name (const char
> +    Initialize various layout_point fields from expanded_location
> +    equivalents; we've already filtered on file.  */
> +
> +-layout_range::layout_range (const expanded_location *start_exploc,
> +-                          const expanded_location *finish_exploc,
> ++layout_range::layout_range (const exploc_with_display_col
> &start_exploc,
> ++                          const exploc_with_display_col
> &finish_exploc,
> +                           enum range_display_kind
> range_display_kind,
> +-                          const expanded_location *caret_exploc,
> ++                          const exploc_with_display_col
> &caret_exploc,
> +                           unsigned original_idx,
> +                           const range_label *label)
> +-: m_start (*start_exploc),
> +-  m_finish (*finish_exploc),
> ++: m_start (start_exploc),
> ++  m_finish (finish_exploc),
> +   m_range_display_kind (range_display_kind),
> +-  m_caret (*caret_exploc),
> ++  m_caret (caret_exploc),
> +   m_original_idx (original_idx),
> +   m_label (label)
> + {
> +@@ -646,6 +643,9 @@ layout_range::intersects_line_p (linenum
> +
> + #if CHECKING_P
> +
> ++/* Default for when we don't care what the tab expansion is set
> to.  */
> ++static const int def_tabstop = 8;
> ++
> + /* Create some expanded locations for testing layout_range.  The
> filename
> +    member of the explocs is set to the empty string.  This member
> will only be
> +    inspected by the calls to location_compute_display_column() made
> from the
> +@@ -662,8 +662,11 @@ make_range (int start_line, int start_co
> +     = {"", start_line, start_col, NULL, false};
> +   const expanded_location finish_exploc
> +     = {"", end_line, end_col, NULL, false};
> +-  return layout_range (&start_exploc, &finish_exploc,
> SHOW_RANGE_WITHOUT_CARET,
> +-                     &start_exploc, 0, NULL);
> ++  return layout_range (exploc_with_display_col (start_exploc,
> def_tabstop),
> ++                     exploc_with_display_col (finish_exploc,
> def_tabstop),
> ++                     SHOW_RANGE_WITHOUT_CARET,
> ++                     exploc_with_display_col (start_exploc,
> def_tabstop),
> ++                     0, NULL);
> + }
> +
> + /* Selftests for layout_range::contains_point and
> +@@ -964,7 +967,7 @@ layout::layout (diagnostic_context * con
> + : m_context (context),
> +   m_pp (context->printer),
> +   m_primary_loc (richloc->get_range (0)->m_loc),
> +-  m_exploc (richloc->get_expanded_location (0)),
> ++  m_exploc (richloc->get_expanded_location (0), context->tabstop),
> +   m_colorizer (context, diagnostic_kind),
> +   m_colorize_source_p (context->colorize_source_p),
> +   m_show_labels_p (context->show_labels_p),
> +@@ -1060,7 +1063,10 @@ layout::maybe_add_location_range (const
> +
> +   /* Everything is now known to be in the correct source file,
> +      but it may require further sanitization.  */
> +-  layout_range ri (&start, &finish, loc_range-
> >m_range_display_kind, &caret,
> ++  layout_range ri (exploc_with_display_col (start, m_context-
> >tabstop),
> ++                 exploc_with_display_col (finish, m_context-
> >tabstop),
> ++                 loc_range->m_range_display_kind,
> ++                 exploc_with_display_col (caret, m_context-
> >tabstop),
> +                  original_idx, loc_range->m_label);
> +
> +   /* If we have a range that finishes before it starts (perhaps
> +@@ -1394,7 +1400,7 @@ layout::calculate_x_offset_display ()
> +     = get_line_bytes_without_trailing_whitespace (line.get_buffer
> (),
> +                                                 line.length ());
> +   int eol_display_column
> +-    = cpp_display_width (line.get_buffer (), line_bytes);
> ++    = cpp_display_width (line.get_buffer (), line_bytes, m_context-
> >tabstop);
> +   if (caret_display_column > eol_display_column
> +       || !caret_display_column)
> +     {
> +@@ -1445,16 +1451,13 @@ layout::calculate_x_offset_display ()
> + }
> +
> + /* Print line ROW of source code, potentially colorized at any
> ranges, and
> +-   populate *LBOUNDS_OUT.
> +-   LINE is the source line (not necessarily 0-terminated) and
> LINE_BYTES
> +-   is its length in bytes.
> +-   This function deals only with byte offsets, not display columns,
> so
> +-   m_x_offset_display must be converted from display to byte
> units.  In
> +-   particular, LINE_BYTES and LBOUNDS_OUT are in bytes.  */
> ++   return the line bounds.  LINE is the source line (not
> necessarily
> ++   0-terminated) and LINE_BYTES is its length in bytes.  In order
> to handle both
> ++   colorization and tab expansion, this function tracks the line
> position in
> ++   both byte and display column units.  */
> +
> +-void
> +-layout::print_source_line (linenum_type row, const char *line, int
> line_bytes,
> +-                         line_bounds *lbounds_out)
> ++line_bounds
> ++layout::print_source_line (linenum_type row, const char *line, int
> line_bytes)
> + {
> +   m_colorizer.set_normal_text ();
> +
> +@@ -1469,30 +1472,29 @@ layout::print_source_line (linenum_type
> +   else
> +     pp_space (m_pp);
> +
> +-  /* We will stop printing the source line at any trailing
> whitespace, and start
> +-     printing it as per m_x_offset_display.  */
> ++  /* We will stop printing the source line at any trailing
> whitespace.  */
> +   line_bytes = get_line_bytes_without_trailing_whitespace (line,
> +
> line_bytes);
> +-  int x_offset_bytes = 0;
> +-  if (m_x_offset_display)
> +-    {
> +-      x_offset_bytes = cpp_display_column_to_byte_column (line,
> line_bytes,
> +-
> m_x_offset_display);
> +-      /* In case the leading portion of the line that will be
> skipped over ends
> +-       with a character with wcwidth > 1, then it is possible we
> skipped too
> +-       much, so account for that by padding with spaces.  */
> +-      const int overage
> +-      = cpp_byte_column_to_display_column (line, line_bytes,
> x_offset_bytes)
> +-      - m_x_offset_display;
> +-      for (int column = 0; column < overage; ++column)
> +-      pp_space (m_pp);
> +-      line += x_offset_bytes;
> +-    }
> +
> +-  /* Print the line.  */
> +-  int first_non_ws = INT_MAX;
> +-  int last_non_ws = 0;
> +-  for (int col_byte = 1 + x_offset_bytes; col_byte <= line_bytes;
> col_byte++)
> ++  /* This object helps to keep track of which display column we are
> at, which is
> ++     necessary for computing the line bounds in display units, for
> doing
> ++     tab expansion, and for implementing m_x_offset_display.  */
> ++  cpp_display_width_computation dw (line, line_bytes, m_context-
> >tabstop);
> ++
> ++  /* Skip the first m_x_offset_display display columns.  In case
> the leading
> ++     portion that will be skipped ends with a character with
> wcwidth > 1, then
> ++     it is possible we skipped too much, so account for that by
> padding with
> ++     spaces.  Note that this does the right thing too in case a tab
> was the last
> ++     character to be skipped over; the tab is effectively replaced
> by the
> ++     correct number of trailing spaces needed to offset by the
> desired number of
> ++     display columns.  */
> ++  for (int skipped_display_cols = dw.advance_display_cols
> (m_x_offset_display);
> ++       skipped_display_cols > m_x_offset_display; --
> skipped_display_cols)
> ++    pp_space (m_pp);
> ++
> ++  /* Print the line and compute the line_bounds.  */
> ++  line_bounds lbounds;
> ++  while (!dw.done ())
> +     {
> +       /* Assuming colorization is enabled for the caret and
> underline
> +        characters, we may also colorize the associated characters
> +@@ -1510,7 +1512,8 @@ layout::print_source_line (linenum_type
> +       {
> +         bool in_range_p;
> +         point_state state;
> +-        in_range_p = get_state_at_point (row, col_byte,
> ++        const int start_byte_col = dw.bytes_processed () + 1;
> ++        in_range_p = get_state_at_point (row, start_byte_col,
> +                                          0, INT_MAX,
> +                                          CU_BYTES,
> +                                          &state);
> +@@ -1519,22 +1522,44 @@ layout::print_source_line (linenum_type
> +         else
> +           m_colorizer.set_normal_text ();
> +       }
> +-      char c = *line;
> +-      if (c == '\0' || c == '\t' || c == '\r')
> +-      c = ' ';
> +-      if (c != ' ')
> ++
> ++      /* Get the display width of the next character to be output,
> expanding
> ++       tabs and replacing some control bytes with spaces as
> necessary.  */
> ++      const char *c = dw.next_byte ();
> ++      const int start_disp_col = dw.display_cols_processed () + 1;
> ++      const int this_display_width = dw.process_next_codepoint ();
> ++      if (*c == '\t')
> ++      {
> ++        /* The returned display width is the number of spaces into
> which the
> ++           tab should be expanded.  */
> ++        for (int i = 0; i != this_display_width; ++i)
> ++          pp_space (m_pp);
> ++        continue;
> ++      }
> ++      if (*c == '\0' || *c == '\r')
> +       {
> +-        last_non_ws = col_byte;
> +-        if (first_non_ws == INT_MAX)
> +-          first_non_ws = col_byte;
> ++        /* cpp_wcwidth() promises to return 1 for all control
> bytes, and we
> ++           want to output these as a single space too, so this case
> is
> ++           actually the same as the '\t' case.  */
> ++        gcc_assert (this_display_width == 1);
> ++        pp_space (m_pp);
> ++        continue;
> +       }
> +-      pp_character (m_pp, c);
> +-      line++;
> ++
> ++      /* We have a (possibly multibyte) character to output; update
> the line
> ++       bounds if it is not whitespace.  */
> ++      if (*c != ' ')
> ++      {
> ++        lbounds.m_last_non_ws_disp_col = dw.display_cols_processed
> ();
> ++        if (lbounds.m_first_non_ws_disp_col == INT_MAX)
> ++          lbounds.m_first_non_ws_disp_col = start_disp_col;
> ++      }
> ++
> ++      /* Output the character.  */
> ++      while (c != dw.next_byte ()) pp_character (m_pp, *c++);
> +     }
> +   print_newline ();
> +-
> +-  lbounds_out->m_first_non_ws = first_non_ws;
> +-  lbounds_out->m_last_non_ws = last_non_ws;
> ++  return lbounds;
> + }
> +
> + /* Determine if we should print an annotation line for ROW.
> +@@ -1576,14 +1601,13 @@ layout::start_annotation_line (char marg
> + }
> +
> + /* Print a line consisting of the caret/underlines for the given
> +-   source line.  This function works with display columns, rather
> than byte
> +-   counts; in particular, LBOUNDS should be in display column
> units.  */
> ++   source line.  */
> +
> + void
> + layout::print_annotation_line (linenum_type row, const line_bounds
> lbounds)
> + {
> +   int x_bound = get_x_bound_for_row (row, m_exploc.m_display_col,
> +-                                   lbounds.m_last_non_ws);
> ++                                   lbounds.m_last_non_ws_disp_col);
> +
> +   start_annotation_line ();
> +   pp_space (m_pp);
> +@@ -1593,8 +1617,8 @@ layout::print_annotation_line (linenum_t
> +       bool in_range_p;
> +       point_state state;
> +       in_range_p = get_state_at_point (row, column,
> +-                                     lbounds.m_first_non_ws,
> +-                                     lbounds.m_last_non_ws,
> ++
> lbounds.m_first_non_ws_disp_col,
> ++
> lbounds.m_last_non_ws_disp_col,
> +                                      CU_DISPLAY_COLS,
> +                                      &state);
> +       if (in_range_p)
> +@@ -1631,12 +1655,14 @@ layout::print_annotation_line (linenum_t
> + class line_label
> + {
> + public:
> +-  line_label (int state_idx, int column, label_text text)
> ++  line_label (diagnostic_context *context, int state_idx, int
> column,
> ++            label_text text)
> +   : m_state_idx (state_idx), m_column (column),
> +     m_text (text), m_label_line (0), m_has_vbar (true)
> +   {
> +     const int bytes = strlen (text.m_buffer);
> +-    m_display_width = cpp_display_width (text.m_buffer, bytes);
> ++    m_display_width
> ++      = cpp_display_width (text.m_buffer, bytes, context->tabstop);
> +   }
> +
> +   /* Sorting is primarily by column, then by state index.  */
> +@@ -1696,7 +1722,7 @@ layout::print_any_labels (linenum_type r
> +       if (text.m_buffer == NULL)
> +         continue;
> +
> +-      labels.safe_push (line_label (i, disp_col, text));
> ++      labels.safe_push (line_label (m_context, i, disp_col, text));
> +       }
> +   }
> +
> +@@ -1976,7 +2002,8 @@ public:
> +
> + /* Get the range of bytes or display columns that HINT would
> affect.  */
> + static column_range
> +-get_affected_range (const fixit_hint *hint, enum column_unit
> col_unit)
> ++get_affected_range (diagnostic_context *context,
> ++                  const fixit_hint *hint, enum column_unit
> col_unit)
> + {
> +   expanded_location exploc_start = expand_location (hint-
> >get_start_loc ());
> +   expanded_location exploc_finish = expand_location (hint-
> >get_next_loc ());
> +@@ -1986,11 +2013,13 @@ get_affected_range (const fixit_hint *hi
> +   int finish_column;
> +   if (col_unit == CU_DISPLAY_COLS)
> +     {
> +-      start_column = location_compute_display_column
> (exploc_start);
> ++      start_column
> ++      = location_compute_display_column (exploc_start, context-
> >tabstop);
> +       if (hint->insertion_p ())
> +       finish_column = start_column - 1;
> +       else
> +-      finish_column = location_compute_display_column
> (exploc_finish);
> ++      finish_column
> ++        = location_compute_display_column (exploc_finish, context-
> >tabstop);
> +     }
> +   else
> +     {
> +@@ -2003,12 +2032,12 @@ get_affected_range (const fixit_hint *hi
> + /* Get the range of display columns that would be printed for
> HINT.  */
> +
> + static column_range
> +-get_printed_columns (const fixit_hint *hint)
> ++get_printed_columns (diagnostic_context *context, const fixit_hint
> *hint)
> + {
> +   expanded_location exploc = expand_location (hint->get_start_loc
> ());
> +-  int start_column = location_compute_display_column (exploc);
> +-  int hint_width = cpp_display_width (hint->get_string (),
> +-                                    hint->get_length ());
> ++  int start_column = location_compute_display_column (exploc,
> context->tabstop);
> ++  int hint_width = cpp_display_width (hint->get_string (), hint-
> >get_length (),
> ++                                    context->tabstop);
> +   int final_hint_column = start_column + hint_width - 1;
> +   if (hint->insertion_p ())
> +     {
> +@@ -2018,7 +2047,8 @@ get_printed_columns (const fixit_hint *h
> +     {
> +       exploc = expand_location (hint->get_next_loc ());
> +       --exploc.column;
> +-      int finish_column = location_compute_display_column (exploc);
> ++      int finish_column
> ++      = location_compute_display_column (exploc, context->tabstop);
> +       return column_range (start_column,
> +                          MAX (finish_column, final_hint_column));
> +     }
> +@@ -2035,12 +2065,14 @@ public:
> +   correction (column_range affected_bytes,
> +             column_range affected_columns,
> +             column_range printed_columns,
> +-            const char *new_text, size_t new_text_len)
> ++            const char *new_text, size_t new_text_len,
> ++            int tabstop)
> +   : m_affected_bytes (affected_bytes),
> +     m_affected_columns (affected_columns),
> +     m_printed_columns (printed_columns),
> +     m_text (xstrdup (new_text)),
> +     m_byte_length (new_text_len),
> ++    m_tabstop (tabstop),
> +     m_alloc_sz (new_text_len + 1)
> +   {
> +     compute_display_cols ();
> +@@ -2058,7 +2090,7 @@ public:
> +
> +   void compute_display_cols ()
> +   {
> +-    m_display_cols = cpp_display_width (m_text, m_byte_length);
> ++    m_display_cols = cpp_display_width (m_text, m_byte_length,
> m_tabstop);
> +   }
> +
> +   void overwrite (int dst_offset, const char_span &src_span)
> +@@ -2086,6 +2118,7 @@ public:
> +   char *m_text;
> +   size_t m_byte_length; /* Not including null-terminator.  */
> +   int m_display_cols;
> ++  int m_tabstop;
> +   size_t m_alloc_sz;
> + };
> +
> +@@ -2121,13 +2154,15 @@ correction::ensure_terminated ()
> + class line_corrections
> + {
> + public:
> +-  line_corrections (const char *filename, linenum_type row)
> +-  : m_filename (filename), m_row (row)
> ++  line_corrections (diagnostic_context *context, const char
> *filename,
> ++                  linenum_type row)
> ++    : m_context (context), m_filename (filename), m_row (row)
> +   {}
> +   ~line_corrections ();
> +
> +   void add_hint (const fixit_hint *hint);
> +
> ++  diagnostic_context *m_context;
> +   const char *m_filename;
> +   linenum_type m_row;
> +   auto_vec <correction *> m_corrections;
> +@@ -2173,9 +2208,10 @@ source_line::source_line (const char *fi
> + void
> + line_corrections::add_hint (const fixit_hint *hint)
> + {
> +-  column_range affected_bytes = get_affected_range (hint,
> CU_BYTES);
> +-  column_range affected_columns = get_affected_range (hint,
> CU_DISPLAY_COLS);
> +-  column_range printed_columns = get_printed_columns (hint);
> ++  column_range affected_bytes = get_affected_range (m_context,
> hint, CU_BYTES);
> ++  column_range affected_columns = get_affected_range (m_context,
> hint,
> ++
> CU_DISPLAY_COLS);
> ++  column_range printed_columns = get_printed_columns (m_context,
> hint);
> +
> +   /* Potentially consolidate.  */
> +   if (!m_corrections.is_empty ())
> +@@ -2243,7 +2279,8 @@ line_corrections::add_hint (const fixit_
> +                                          affected_columns,
> +                                          printed_columns,
> +                                          hint->get_string (),
> +-                                         hint->get_length ()));
> ++                                         hint->get_length (),
> ++                                         m_context->tabstop));
> + }
> +
> + /* If there are any fixit hints on source line ROW, print them.
> +@@ -2257,7 +2294,7 @@ layout::print_trailing_fixits (linenum_t
> + {
> +   /* Build a list of correction instances for the line,
> +      potentially consolidating hints (for the sake of
> readability).  */
> +-  line_corrections corrections (m_exploc.file, row);
> ++  line_corrections corrections (m_context, m_exploc.file, row);
> +   for (unsigned int i = 0; i < m_fixit_hints.length (); i++)
> +     {
> +       const fixit_hint *hint = m_fixit_hints[i];
> +@@ -2499,15 +2536,11 @@ layout::print_line (linenum_type row)
> +   if (!line)
> +     return;
> +
> +-  line_bounds lbounds;
> +   print_leading_fixits (row);
> +-  print_source_line (row, line.get_buffer (), line.length (),
> &lbounds);
> ++  const line_bounds lbounds
> ++    = print_source_line (row, line.get_buffer (), line.length ());
> +   if (should_print_annotation_line_p (row))
> +-    {
> +-      if (lbounds.m_first_non_ws != INT_MAX)
> +-      lbounds.convert_to_display_cols (line);
> +-      print_annotation_line (row, lbounds);
> +-    }
> ++    print_annotation_line (row, lbounds);
> +   if (m_show_labels_p)
> +     print_any_labels (row);
> +   print_trailing_fixits (row);
> +@@ -2670,9 +2703,11 @@ test_layout_x_offset_display_utf8 (const
> +
> +   char_span lspan = location_get_source_line (tmp.get_filename (),
> 1);
> +   ASSERT_EQ (line_display_cols,
> +-           cpp_display_width (lspan.get_buffer (), lspan.length
> ()));
> ++           cpp_display_width (lspan.get_buffer (), lspan.length (),
> ++                              def_tabstop));
> +   ASSERT_EQ (line_display_cols,
> +-           location_compute_display_column (expand_location
> (line_end)));
> ++           location_compute_display_column (expand_location
> (line_end),
> ++                                            def_tabstop));
> +   ASSERT_EQ (0, memcmp (lspan.get_buffer () + (emoji_col - 1),
> +                       "\xf0\x9f\x98\x82\xf0\x9f\x98\x82", 8));
> +
> +@@ -2774,6 +2809,111 @@ test_layout_x_offset_display_utf8 (const
> +
> + }
> +
> ++static void
> ++test_layout_x_offset_display_tab (const line_table_case &case_)
> ++{
> ++  const char *content
> ++    = "This line is very long, so that we can use it to test the
> logic for "
> ++      "clipping long lines.  Also this: `\t' is a tab that occupies
> 1 byte and "
> ++      "a variable number of display columns, starting at column
> #103.\n";
> ++
> ++  /* Number of bytes in the line, subtracting one to remove the
> newline.  */
> ++  const int line_bytes = strlen (content) - 1;
> ++
> ++ /* The column where the tab begins.  Byte or display is the same
> as there are
> ++    no multibyte characters earlier on the line.  */
> ++  const int tab_col = 103;
> ++
> ++  /* Effective extra size of the tab beyond what a single space
> would have taken
> ++     up, indexed by tabstop.  */
> ++  static const int num_tabstops = 11;
> ++  int extra_width[num_tabstops];
> ++  for (int tabstop = 1; tabstop != num_tabstops; ++tabstop)
> ++    {
> ++      const int this_tab_size = tabstop - (tab_col - 1) % tabstop;
> ++      extra_width[tabstop] = this_tab_size - 1;
> ++    }
> ++  /* Example of this calculation: if tabstop is 10, the tab
> starting at column
> ++     #103 has to expand into 8 spaces, covering columns 103-110, so
> that the
> ++     next character is at column #111.  So it takes up 7 more
> columns than
> ++     a space would have taken up.  */
> ++  ASSERT_EQ (7, extra_width[10]);
> ++
> ++  temp_source_file tmp (SELFTEST_LOCATION, ".c", content);
> ++  line_table_test ltt (case_);
> ++
> ++  linemap_add (line_table, LC_ENTER, false, tmp.get_filename (),
> 1);
> ++
> ++  location_t line_end = linemap_position_for_column (line_table,
> line_bytes);
> ++
> ++  /* Don't attempt to run the tests if column data might be
> unavailable.  */
> ++  if (line_end > LINE_MAP_MAX_LOCATION_WITH_COLS)
> ++    return;
> ++
> ++  /* Check that cpp_display_width handles the tabs as expected.  */
> ++  char_span lspan = location_get_source_line (tmp.get_filename (),
> 1);
> ++  ASSERT_EQ ('\t', *(lspan.get_buffer () + (tab_col - 1)));
> ++  for (int tabstop = 1; tabstop != num_tabstops; ++tabstop)
> ++    {
> ++      ASSERT_EQ (line_bytes + extra_width[tabstop],
> ++               cpp_display_width (lspan.get_buffer (), lspan.length
> (),
> ++                                  tabstop));
> ++      ASSERT_EQ (line_bytes + extra_width[tabstop],
> ++               location_compute_display_column (expand_location
> (line_end),
> ++                                                tabstop));
> ++    }
> ++
> ++  /* Check that the tab is expanded to the expected number of
> spaces.  */
> ++  rich_location richloc (line_table,
> ++                       linemap_position_for_column (line_table,
> ++                                                    tab_col + 1));
> ++  for (int tabstop = 1; tabstop != num_tabstops; ++tabstop)
> ++    {
> ++      test_diagnostic_context dc;
> ++      dc.tabstop = tabstop;
> ++      layout test_layout (&dc, &richloc, DK_ERROR);
> ++      test_layout.print_line (1);
> ++      const char *out = pp_formatted_text (dc.printer);
> ++      ASSERT_EQ (NULL, strchr (out, '\t'));
> ++      const char *left_quote = strchr (out, '`');
> ++      const char *right_quote = strchr (out, '\'');
> ++      ASSERT_NE (NULL, left_quote);
> ++      ASSERT_NE (NULL, right_quote);
> ++      ASSERT_EQ (right_quote - left_quote, extra_width[tabstop] +
> 2);
> ++    }
> ++
> ++  /* Check that the line is offset properly and that the tab is
> broken up
> ++     into the expected number of spaces when it is the last
> character skipped
> ++     over.  */
> ++  for (int tabstop = 1; tabstop != num_tabstops; ++tabstop)
> ++    {
> ++      test_diagnostic_context dc;
> ++      dc.tabstop = tabstop;
> ++      static const int small_width = 24;
> ++      dc.caret_max_width = small_width - 4;
> ++      dc.min_margin_width = test_left_margin - test_linenum_sep +
> 1;
> ++      dc.show_line_numbers_p = true;
> ++      layout test_layout (&dc, &richloc, DK_ERROR);
> ++      test_layout.print_line (1);
> ++
> ++      /* We have arranged things so that two columns will be
> printed before
> ++       the caret.  If the tab results in more than one space, this
> should
> ++       produce two spaces in the output; otherwise, it will be a
> single space
> ++       preceded by the opening quote before the tab character.  */
> ++      const char *output1
> ++      = "   1 |   ' is a tab that occupies 1 byte and a variable
> number of "
> ++        "display columns, starting at column #103.\n"
> ++        "     |   ^\n\n";
> ++      const char *output2
> ++      = "   1 | ` ' is a tab that occupies 1 byte and a variable
> number of "
> ++        "display columns, starting at column #103.\n"
> ++        "     |   ^\n\n";
> ++      const char *expected_output = (extra_width[tabstop] ? output1
> : output2);
> ++      ASSERT_STREQ (expected_output, pp_formatted_text
> (dc.printer));
> ++    }
> ++}
> ++
> ++
> + /* Verify that diagnostic_show_locus works sanely on
> UNKNOWN_LOCATION.  */
> +
> + static void
> +@@ -3854,6 +3994,27 @@ test_one_liner_labels_utf8 ()
> +   }
> + }
> +
> ++/* Make sure that colorization codes don't interrupt a multibyte
> ++   sequence, which would corrupt it.  */
> ++static void
> ++test_one_liner_colorized_utf8 ()
> ++{
> ++  test_diagnostic_context dc;
> ++  dc.colorize_source_p = true;
> ++  diagnostic_color_init (&dc, DIAGNOSTICS_COLOR_YES);
> ++  const location_t pi = linemap_position_for_column (line_table,
> 12);
> ++  rich_location richloc (line_table, pi);
> ++  diagnostic_show_locus (&dc, &richloc, DK_ERROR);
> ++
> ++  /* In order to avoid having the test depend on exactly how the
> colorization
> ++     was effected, just confirm there are two pi characters in the
> output.  */
> ++  const char *result = pp_formatted_text (dc.printer);
> ++  const char *null_term = result + strlen (result);
> ++  const char *first_pi = strstr (result, "\xcf\x80");
> ++  ASSERT_TRUE (first_pi && first_pi <= null_term - 2);
> ++  ASSERT_STR_CONTAINS (first_pi + 2, "\xcf\x80");
> ++}
> ++
> + /* Run the various one-liner tests.  */
> +
> + static void
> +@@ -3884,8 +4045,10 @@ test_diagnostic_show_locus_one_liner_utf
> +   ASSERT_EQ (31, LOCATION_COLUMN (line_end));
> +
> +   char_span lspan = location_get_source_line (tmp.get_filename (),
> 1);
> +-  ASSERT_EQ (25, cpp_display_width (lspan.get_buffer (),
> lspan.length ()));
> +-  ASSERT_EQ (25, location_compute_display_column (expand_location
> (line_end)));
> ++  ASSERT_EQ (25, cpp_display_width (lspan.get_buffer (),
> lspan.length (),
> ++                                  def_tabstop));
> ++  ASSERT_EQ (25, location_compute_display_column (expand_location
> (line_end),
> ++                                                def_tabstop));
> +
> +   test_one_liner_simple_caret_utf8 ();
> +   test_one_liner_caret_and_range_utf8 ();
> +@@ -3900,6 +4063,7 @@ test_diagnostic_show_locus_one_liner_utf
> +   test_one_liner_many_fixits_1_utf8 ();
> +   test_one_liner_many_fixits_2_utf8 ();
> +   test_one_liner_labels_utf8 ();
> ++  test_one_liner_colorized_utf8 ();
> + }
> +
> + /* Verify that gcc_rich_location::add_location_if_nearby works.  */
> +@@ -4272,25 +4436,28 @@ test_overlapped_fixit_printing (const li
> +     /* Unit-test the line_corrections machinery.  */
> +     ASSERT_EQ (3, richloc.get_num_fixit_hints ());
> +     const fixit_hint *hint_0 = richloc.get_fixit_hint (0);
> +-    ASSERT_EQ (column_range (12, 12), get_affected_range (hint_0,
> CU_BYTES));
> +     ASSERT_EQ (column_range (12, 12),
> +-                         get_affected_range (hint_0,
> CU_DISPLAY_COLS));
> +-    ASSERT_EQ (column_range (12, 22), get_printed_columns
> (hint_0));
> ++             get_affected_range (&dc, hint_0, CU_BYTES));
> ++    ASSERT_EQ (column_range (12, 12),
> ++             get_affected_range (&dc, hint_0, CU_DISPLAY_COLS));
> ++    ASSERT_EQ (column_range (12, 22), get_printed_columns (&dc,
> hint_0));
> +     const fixit_hint *hint_1 = richloc.get_fixit_hint (1);
> +-    ASSERT_EQ (column_range (18, 18), get_affected_range (hint_1,
> CU_BYTES));
> +     ASSERT_EQ (column_range (18, 18),
> +-                         get_affected_range (hint_1,
> CU_DISPLAY_COLS));
> +-    ASSERT_EQ (column_range (18, 20), get_printed_columns
> (hint_1));
> ++             get_affected_range (&dc, hint_1, CU_BYTES));
> ++    ASSERT_EQ (column_range (18, 18),
> ++             get_affected_range (&dc, hint_1, CU_DISPLAY_COLS));
> ++    ASSERT_EQ (column_range (18, 20), get_printed_columns (&dc,
> hint_1));
> +     const fixit_hint *hint_2 = richloc.get_fixit_hint (2);
> +-    ASSERT_EQ (column_range (29, 28), get_affected_range (hint_2,
> CU_BYTES));
> +     ASSERT_EQ (column_range (29, 28),
> +-                         get_affected_range (hint_2,
> CU_DISPLAY_COLS));
> +-    ASSERT_EQ (column_range (29, 29), get_printed_columns
> (hint_2));
> ++             get_affected_range (&dc, hint_2, CU_BYTES));
> ++    ASSERT_EQ (column_range (29, 28),
> ++             get_affected_range (&dc, hint_2, CU_DISPLAY_COLS));
> ++    ASSERT_EQ (column_range (29, 29), get_printed_columns (&dc,
> hint_2));
> +
> +     /* Add each hint in turn to a line_corrections instance,
> +        and verify that they are consolidated into one correction
> instance
> +        as expected.  */
> +-    line_corrections lc (tmp.get_filename (), 1);
> ++    line_corrections lc (&dc, tmp.get_filename (), 1);
> +
> +     /* The first replace hint by itself.  */
> +     lc.add_hint (hint_0);
> +@@ -4484,25 +4651,28 @@ test_overlapped_fixit_printing_utf8 (con
> +     /* Unit-test the line_corrections machinery.  */
> +     ASSERT_EQ (3, richloc.get_num_fixit_hints ());
> +     const fixit_hint *hint_0 = richloc.get_fixit_hint (0);
> +-    ASSERT_EQ (column_range (14, 14), get_affected_range (hint_0,
> CU_BYTES));
> ++    ASSERT_EQ (column_range (14, 14),
> ++             get_affected_range (&dc, hint_0, CU_BYTES));
> +     ASSERT_EQ (column_range (12, 12),
> +-                         get_affected_range (hint_0,
> CU_DISPLAY_COLS));
> +-    ASSERT_EQ (column_range (12, 22), get_printed_columns
> (hint_0));
> ++             get_affected_range (&dc, hint_0, CU_DISPLAY_COLS));
> ++    ASSERT_EQ (column_range (12, 22), get_printed_columns (&dc,
> hint_0));
> +     const fixit_hint *hint_1 = richloc.get_fixit_hint (1);
> +-    ASSERT_EQ (column_range (22, 22), get_affected_range (hint_1,
> CU_BYTES));
> ++    ASSERT_EQ (column_range (22, 22),
> ++             get_affected_range (&dc, hint_1, CU_BYTES));
> +     ASSERT_EQ (column_range (18, 18),
> +-                         get_affected_range (hint_1,
> CU_DISPLAY_COLS));
> +-    ASSERT_EQ (column_range (18, 20), get_printed_columns
> (hint_1));
> ++             get_affected_range (&dc, hint_1, CU_DISPLAY_COLS));
> ++    ASSERT_EQ (column_range (18, 20), get_printed_columns (&dc,
> hint_1));
> +     const fixit_hint *hint_2 = richloc.get_fixit_hint (2);
> +-    ASSERT_EQ (column_range (35, 34), get_affected_range (hint_2,
> CU_BYTES));
> ++    ASSERT_EQ (column_range (35, 34),
> ++             get_affected_range (&dc, hint_2, CU_BYTES));
> +     ASSERT_EQ (column_range (30, 29),
> +-                         get_affected_range (hint_2,
> CU_DISPLAY_COLS));
> +-    ASSERT_EQ (column_range (30, 30), get_printed_columns
> (hint_2));
> ++             get_affected_range (&dc, hint_2, CU_DISPLAY_COLS));
> ++    ASSERT_EQ (column_range (30, 30), get_printed_columns (&dc,
> hint_2));
> +
> +     /* Add each hint in turn to a line_corrections instance,
> +        and verify that they are consolidated into one correction
> instance
> +        as expected.  */
> +-    line_corrections lc (tmp.get_filename (), 1);
> ++    line_corrections lc (&dc, tmp.get_filename (), 1);
> +
> +     /* The first replace hint by itself.  */
> +     lc.add_hint (hint_0);
> +@@ -4689,6 +4859,8 @@ test_overlapped_fixit_printing_2 (const
> +
> +   /* Two insertions, in the wrong order.  */
> +   {
> ++    test_diagnostic_context dc;
> ++
> +     rich_location richloc (line_table, col_20);
> +     richloc.add_fixit_insert_before (col_23, "{");
> +     richloc.add_fixit_insert_before (col_21, "}");
> +@@ -4696,14 +4868,15 @@ test_overlapped_fixit_printing_2 (const
> +     /* These fixits should be accepted; they can't be
> consolidated.  */
> +     ASSERT_EQ (2, richloc.get_num_fixit_hints ());
> +     const fixit_hint *hint_0 = richloc.get_fixit_hint (0);
> +-    ASSERT_EQ (column_range (23, 22), get_affected_range (hint_0,
> CU_BYTES));
> +-    ASSERT_EQ (column_range (23, 23), get_printed_columns
> (hint_0));
> ++    ASSERT_EQ (column_range (23, 22),
> ++             get_affected_range (&dc, hint_0, CU_BYTES));
> ++    ASSERT_EQ (column_range (23, 23), get_printed_columns (&dc,
> hint_0));
> +     const fixit_hint *hint_1 = richloc.get_fixit_hint (1);
> +-    ASSERT_EQ (column_range (21, 20), get_affected_range (hint_1,
> CU_BYTES));
> +-    ASSERT_EQ (column_range (21, 21), get_printed_columns
> (hint_1));
> ++    ASSERT_EQ (column_range (21, 20),
> ++             get_affected_range (&dc, hint_1, CU_BYTES));
> ++    ASSERT_EQ (column_range (21, 21), get_printed_columns (&dc,
> hint_1));
> +
> +     /* Verify that they're printed correctly.  */
> +-    test_diagnostic_context dc;
> +     diagnostic_show_locus (&dc, &richloc, DK_ERROR);
> +     ASSERT_STREQ (" int a5[][0][0] = { 1, 2 };\n"
> +                 "                    ^\n"
> +@@ -4955,6 +5128,65 @@ test_fixit_deletion_affecting_newline (c
> +               pp_formatted_text (dc.printer));
> + }
> +
> ++static void
> ++test_tab_expansion (const line_table_case &case_)
> ++{
> ++  /* Create a tempfile and write some text to it.  This example
> uses a tabstop
> ++     of 8, as the column numbers attempt to indicate:
> ++
> ++    .....................000.01111111111.22222333333  display
> ++    .....................123.90123456789.56789012345  columns  */
> ++  const char *content = "  \t   This: `\t' is a tab.\n";
> ++  /* ....................000 00000011111 11111222222  byte
> ++     ....................123 45678901234 56789012345  columns  */
> ++
> ++  const int tabstop = 8;
> ++  const int first_non_ws_byte_col = 7;
> ++  const int right_quote_byte_col = 15;
> ++  const int last_byte_col = 25;
> ++  ASSERT_EQ (35, cpp_display_width (content, last_byte_col,
> tabstop));
> ++
> ++  temp_source_file tmp (SELFTEST_LOCATION, ".c", content);
> ++  line_table_test ltt (case_);
> ++  linemap_add (line_table, LC_ENTER, false, tmp.get_filename (),
> 1);
> ++
> ++  /* Don't attempt to run the tests if column data might be
> unavailable.  */
> ++  location_t line_end = linemap_position_for_column (line_table,
> last_byte_col);
> ++  if (line_end > LINE_MAP_MAX_LOCATION_WITH_COLS)
> ++    return;
> ++
> ++  /* Check that the leading whitespace with mixed tabs and spaces
> is expanded
> ++     into 11 spaces.  Recall that print_line() also puts one space
> before
> ++     everything too.  */
> ++  {
> ++    test_diagnostic_context dc;
> ++    dc.tabstop = tabstop;
> ++    rich_location richloc (line_table,
> ++                         linemap_position_for_column (line_table,
> ++                                                      first_non_ws_
> byte_col));
> ++    layout test_layout (&dc, &richloc, DK_ERROR);
> ++    test_layout.print_line (1);
> ++    ASSERT_STREQ ("            This: `      ' is a tab.\n"
> ++                "            ^\n",
> ++                pp_formatted_text (dc.printer));
> ++  }
> ++
> ++  /* Confirm the display width was tracked correctly across the
> internal tab
> ++     as well.  */
> ++  {
> ++    test_diagnostic_context dc;
> ++    dc.tabstop = tabstop;
> ++    rich_location richloc (line_table,
> ++                         linemap_position_for_column (line_table,
> ++                                                      right_quote_b
> yte_col));
> ++    layout test_layout (&dc, &richloc, DK_ERROR);
> ++    test_layout.print_line (1);
> ++    ASSERT_STREQ ("            This: `      ' is a tab.\n"
> ++                "                         ^\n",
> ++                pp_formatted_text (dc.printer));
> ++  }
> ++}
> ++
> + /* Verify that line numbers are correctly printed for the case of
> +    a multiline range in which the width of the line numbers changes
> +    (e.g. from "9" to "10").  */
> +@@ -5012,6 +5244,7 @@ diagnostic_show_locus_c_tests ()
> +   test_layout_range_for_multiple_lines ();
> +
> +   for_each_line_table_case (test_layout_x_offset_display_utf8);
> ++  for_each_line_table_case (test_layout_x_offset_display_tab);
> +
> +   test_get_line_bytes_without_trailing_whitespace ();
> +
> +@@ -5029,6 +5262,7 @@ diagnostic_show_locus_c_tests ()
> +   for_each_line_table_case
> (test_fixit_insert_containing_newline_2);
> +   for_each_line_table_case (test_fixit_replace_containing_newline);
> +   for_each_line_table_case (test_fixit_deletion_affecting_newline);
> ++  for_each_line_table_case (test_tab_expansion);
> +
> +   test_line_numbers_multiline_range ();
> + }
> +diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> +--- a/gcc/doc/invoke.texi      2021-12-24 20:23:46.876739587 -0800
> ++++ b/gcc/doc/invoke.texi      2021-12-25 01:20:53.487636494 -0800
> +@@ -293,7 +293,9 @@ Objective-C and Objective-C++ Dialects}.
> + -fdiagnostics-show-template-tree  -fno-elide-type @gol
> +
> -fdiagnostics-path-format=@r{[}none@r{|}separate-events@r{|}inline-events@r{
> ]} @gol
> + -fdiagnostics-show-path-depths @gol
> +--fno-show-column}
> ++-fno-show-column @gol
> ++-fdiagnostics-column-unit=@r{[}display@r{|}byte@r{]} @gol
> ++-fdiagnostics-column-origin=@var{origin}}
> +
> + @item Warning Options
> + @xref{Warning Options,,Options to Request or Suppress Warnings}.
> +@@ -4424,6 +4426,31 @@ Do not print column numbers in diagnosti
> + diagnostics are being scanned by a program that does not understand
> the
> + column numbers, such as @command{dejagnu}.
> +
> ++@item -fdiagnostics-column-unit=@var{UNIT}
> ++@opindex fdiagnostics-column-unit
> ++Select the units for the column number.  This affects traditional
> diagnostics
> ++(in the absence of @option{-fno-show-column}), as well as JSON
> format
> ++diagnostics if requested.
> ++
> ++The default @var{UNIT}, @samp{display}, considers the number of
> display
> ++columns occupied by each character.  This may be larger than the
> number
> ++of bytes required to encode the character, in the case of tab
> ++characters, or it may be smaller, in the case of multibyte
> characters.
> ++For example, the character ``GREEK SMALL LETTER PI (U+03C0)''
> occupies one
> ++display column, and its UTF-8 encoding requires two bytes; the
> character
> ++``SLIGHTLY SMILING FACE (U+1F642)'' occupies two display columns,
> and
> ++its UTF-8 encoding requires four bytes.
> ++
> ++Setting @var{UNIT} to @samp{byte} changes the column number to the
> raw byte
> ++count in all cases, as was traditionally output by GCC prior to
> version 11.1.0.
> ++
> ++@item -fdiagnostics-column-origin=@var{ORIGIN}
> ++@opindex fdiagnostics-column-origin
> ++Select the origin for column numbers, i.e. the column number
> assigned to the
> ++first column.  The default value of 1 corresponds to traditional
> GCC
> ++behavior and to the GNU style guide.  Some utilities may perform
> better with an
> ++origin of 0; any non-negative value may be specified.
> ++
> + @item -fdiagnostics-format=@var{FORMAT}
> + @opindex fdiagnostics-format
> + Select a different format for printing diagnostics.
> +@@ -4459,11 +4486,15 @@ might be printed in JSON form (after for
> +         "locations": [
> +             @{
> +                 "caret": @{
> ++                  "display-column": 3,
> ++                  "byte-column": 3,
> +                     "column": 3,
> +                     "file": "misleading-indentation.c",
> +                     "line": 15
> +                 @},
> +                 "finish": @{
> ++                  "display-column": 4,
> ++                  "byte-column": 4,
> +                     "column": 4,
> +                     "file": "misleading-indentation.c",
> +                     "line": 15
> +@@ -4479,6 +4510,8 @@ might be printed in JSON form (after for
> +                 "locations": [
> +                     @{
> +                         "caret": @{
> ++                          "display-column": 5,
> ++                          "byte-column": 5,
> +                             "column": 5,
> +                             "file": "misleading-indentation.c",
> +                             "line": 17
> +@@ -4488,6 +4521,7 @@ might be printed in JSON form (after for
> +                 "message": "...this statement, but the latter is
> @dots{}"
> +             @}
> +         ]
> ++      "column-origin": 1,
> +     @},
> +     @dots{}
> + ]
> +@@ -4500,10 +4534,34 @@ A diagnostic has a @code{kind}.  If this
> + an @code{option} key describing the command-line option controlling
> the
> + warning.
> +
> +-A diagnostic can contain zero or more locations.  Each location has
> up
> +-to three positions within it: a @code{caret} position and optional
> +-@code{start} and @code{finish} positions.  A location can also have
> +-an optional @code{label} string.  For example, this error:
> ++A diagnostic can contain zero or more locations.  Each location has
> an
> ++optional @code{label} string and up to three positions within it: a
> ++@code{caret} position and optional @code{start} and @code{finish}
> positions.
> ++A position is described by a @code{file} name, a @code{line}
> number, and
> ++three numbers indicating a column position:
> ++@itemize @bullet
> ++
> ++@item
> ++@code{display-column} counts display columns, accounting for tabs
> and
> ++multibyte characters.
> ++
> ++@item
> ++@code{byte-column} counts raw bytes.
> ++
> ++@item
> ++@code{column} is equal to one of
> ++the previous two, as dictated by the @option{-fdiagnostics-column-
> unit}
> ++option.
> ++
> ++@end itemize
> ++All three columns are relative to the origin specified by
> ++@option{-fdiagnostics-column-origin}, which is typically equal to 1
> but may
> ++be set, for instance, to 0 for compatibility with other utilities
> that
> ++number columns from 0.  The column origin is recorded in the JSON
> output in
> ++the @code{column-origin} tag.  In the remaining examples below, the
> extra
> ++column number outputs have been omitted for brevity.
> ++
> ++For example, this error:
> +
> + @smallexample
> + bad-binary-ops.c:64:23: error: invalid operands to binary + (have
> 'S' @{aka
> +diff --git a/gcc/input.c b/gcc/input.c
> +--- a/gcc/input.c      2020-07-22 23:35:17.664388078 -0700
> ++++ b/gcc/input.c      2021-12-25 01:20:53.487636494 -0800
> +@@ -913,7 +913,7 @@ make_location (location_t caret, source_
> +    source line in order to calculate the display width.  If that
> cannot be done
> +    for any reason, then returns the byte column as a fallback.  */
> + int
> +-location_compute_display_column (expanded_location exploc)
> ++location_compute_display_column (expanded_location exploc, int
> tabstop)
> + {
> +   if (!(exploc.file && *exploc.file && exploc.line &&
> exploc.column))
> +     return exploc.column;
> +@@ -921,7 +921,7 @@ location_compute_display_column (expande
> +   /* If line is NULL, this function returns exploc.column which is
> the
> +      desired fallback.  */
> +   return cpp_byte_column_to_display_column (line.get_buffer (),
> line.length (),
> +-                                          exploc.column);
> ++                                          exploc.column, tabstop);
> + }
> +
> + /* Dump statistics to stderr about the memory usage of the
> line_table
> +@@ -3608,33 +3608,46 @@ test_line_offset_overflow ()
> +
> + void test_cpp_utf8 ()
> + {
> ++  const int def_tabstop = 8;
> +   /* Verify that wcwidth of invalid UTF-8 or control bytes is 1.
> */
> +   {
> +-    int w_bad = cpp_display_width ("\xf0!\x9f!\x98!\x82!", 8);
> ++    int w_bad = cpp_display_width ("\xf0!\x9f!\x98!\x82!", 8,
> def_tabstop);
> +     ASSERT_EQ (8, w_bad);
> +-    int w_ctrl = cpp_display_width ("\r\t\n\v\0\1", 6);
> +-    ASSERT_EQ (6, w_ctrl);
> ++    int w_ctrl = cpp_display_width ("\r\n\v\0\1", 5, def_tabstop);
> ++    ASSERT_EQ (5, w_ctrl);
> +   }
> +
> +   /* Verify that wcwidth of valid UTF-8 is as expected.  */
> +   {
> +-    const int w_pi = cpp_display_width ("\xcf\x80", 2);
> ++    const int w_pi = cpp_display_width ("\xcf\x80", 2,
> def_tabstop);
> +     ASSERT_EQ (1, w_pi);
> +-    const int w_emoji = cpp_display_width ("\xf0\x9f\x98\x82", 4);
> ++    const int w_emoji = cpp_display_width ("\xf0\x9f\x98\x82", 4,
> def_tabstop);
> +     ASSERT_EQ (2, w_emoji);
> +-    const int w_umlaut_precomposed = cpp_display_width ("\xc3\xbf",
> 2);
> ++    const int w_umlaut_precomposed = cpp_display_width ("\xc3\xbf",
> 2,
> ++                                                      def_tabstop);
> +     ASSERT_EQ (1, w_umlaut_precomposed);
> +-    const int w_umlaut_combining = cpp_display_width ("y\xcc\x88",
> 3);
> ++    const int w_umlaut_combining = cpp_display_width ("y\xcc\x88",
> 3,
> ++                                                    def_tabstop);
> +     ASSERT_EQ (1, w_umlaut_combining);
> +-    const int w_han = cpp_display_width ("\xe4\xb8\xba", 3);
> ++    const int w_han = cpp_display_width ("\xe4\xb8\xba", 3,
> def_tabstop);
> +     ASSERT_EQ (2, w_han);
> +-    const int w_ascii = cpp_display_width ("GCC", 3);
> ++    const int w_ascii = cpp_display_width ("GCC", 3, def_tabstop);
> +     ASSERT_EQ (3, w_ascii);
> +     const int w_mixed = cpp_display_width ("\xcf\x80 = 3.14
> \xf0\x9f\x98\x82"
> +-                                         "\x9f! \xe4\xb8\xba
> y\xcc\x88", 24);
> ++                                         "\x9f! \xe4\xb8\xba
> y\xcc\x88",
> ++                                         24, def_tabstop);
> +     ASSERT_EQ (18, w_mixed);
> +   }
> +
> ++  /* Verify that display width properly expands tabs.  */
> ++  {
> ++    const char *tstr = "\tabc\td";
> ++    ASSERT_EQ (6, cpp_display_width (tstr, 6, 1));
> ++    ASSERT_EQ (10, cpp_display_width (tstr, 6, 3));
> ++    ASSERT_EQ (17, cpp_display_width (tstr, 6, 8));
> ++    ASSERT_EQ (1, cpp_display_column_to_byte_column (tstr, 6, 7,
> 8));
> ++  }
> ++
> +   /* Verify that cpp_byte_column_to_display_column can go past the
> end,
> +      and similar edge cases.  */
> +   {
> +@@ -3645,10 +3658,13 @@ void test_cpp_utf8 ()
> +       /* 111122223456
> +        Byte columns.  */
> +
> +-    ASSERT_EQ (5, cpp_display_width (str, 6));
> +-    ASSERT_EQ (105, cpp_byte_column_to_display_column (str, 6,
> 106));
> +-    ASSERT_EQ (10000, cpp_byte_column_to_display_column (NULL, 0,
> 10000));
> +-    ASSERT_EQ (0, cpp_byte_column_to_display_column (NULL, 10000,
> 0));
> ++    ASSERT_EQ (5, cpp_display_width (str, 6, def_tabstop));
> ++    ASSERT_EQ (105,
> ++             cpp_byte_column_to_display_column (str, 6, 106,
> def_tabstop));
> ++    ASSERT_EQ (10000,
> ++             cpp_byte_column_to_display_column (NULL, 0, 10000,
> def_tabstop));
> ++    ASSERT_EQ (0,
> ++             cpp_byte_column_to_display_column (NULL, 10000, 0,
> def_tabstop));
> +   }
> +
> +   /* Verify that cpp_display_column_to_byte_column can go past the
> end,
> +@@ -3662,21 +3678,25 @@ void test_cpp_utf8 ()
> +       /* 000000000000000000000000000000000111111
> +        111122223333444456666777788889999012345
> +        Byte columns.  */
> +-    ASSERT_EQ (4, cpp_display_column_to_byte_column (str, 15, 2));
> +-    ASSERT_EQ (15, cpp_display_column_to_byte_column (str, 15,
> 11));
> +-    ASSERT_EQ (115, cpp_display_column_to_byte_column (str, 15,
> 111));
> +-    ASSERT_EQ (10000, cpp_display_column_to_byte_column (NULL, 0,
> 10000));
> +-    ASSERT_EQ (0, cpp_display_column_to_byte_column (NULL, 10000,
> 0));
> ++    ASSERT_EQ (4, cpp_display_column_to_byte_column (str, 15, 2,
> def_tabstop));
> ++    ASSERT_EQ (15,
> ++             cpp_display_column_to_byte_column (str, 15, 11,
> def_tabstop));
> ++    ASSERT_EQ (115,
> ++             cpp_display_column_to_byte_column (str, 15, 111,
> def_tabstop));
> ++    ASSERT_EQ (10000,
> ++             cpp_display_column_to_byte_column (NULL, 0, 10000,
> def_tabstop));
> ++    ASSERT_EQ (0,
> ++             cpp_display_column_to_byte_column (NULL, 10000, 0,
> def_tabstop));
> +
> +     /* Verify that we do not interrupt a UTF-8 sequence.  */
> +-    ASSERT_EQ (4, cpp_display_column_to_byte_column (str, 15, 1));
> ++    ASSERT_EQ (4, cpp_display_column_to_byte_column (str, 15, 1,
> def_tabstop));
> +
> +     for (int byte_col = 1; byte_col <= 15; ++byte_col)
> +       {
> +-      const int disp_col = cpp_byte_column_to_display_column (str,
> 15,
> +-
>                                                               byte_co
> l);
> +-      const int byte_col2 = cpp_display_column_to_byte_column (str,
> 15,
> +-
> disp_col);
> ++      const int disp_col
> ++        = cpp_byte_column_to_display_column (str, 15, byte_col,
> def_tabstop);
> ++      const int byte_col2
> ++        = cpp_display_column_to_byte_column (str, 15, disp_col,
> def_tabstop);
> +
> +       /* If we ask for the display column in the middle of a UTF-8
> +          sequence, it will return the length of the partial
> sequence,
> +diff --git a/gcc/input.h b/gcc/input.h
> +--- a/gcc/input.h      2020-07-22 23:35:17.664388078 -0700
> ++++ b/gcc/input.h      2021-12-25 01:20:53.487636494 -0800
> +@@ -38,7 +38,9 @@ STATIC_ASSERT (BUILTINS_LOCATION < RESER
> +
> + extern bool is_location_from_builtin_token (location_t);
> + extern expanded_location expand_location (location_t);
> +-extern int location_compute_display_column (expanded_location);
> ++
> ++extern int location_compute_display_column (expanded_location
> exploc,
> ++                                          int tabstop);
> +
> + /* A class capturing the bounds of a buffer, to allow for run-time
> +    bounds-checking in a checked build.  */
> +diff --git a/gcc/opts.c b/gcc/opts.c
> +--- a/gcc/opts.c       2020-07-22 23:35:17.708388562 -0700
> ++++ b/gcc/opts.c       2021-12-25 01:20:53.487636494 -0800
> +@@ -2439,6 +2439,14 @@ common_handle_option (struct gcc_options
> +       dc->parseable_fixits_p = value;
> +       break;
> +
> ++    case OPT_fdiagnostics_column_unit_:
> ++      dc->column_unit = (enum diagnostics_column_unit)value;
> ++      break;
> ++
> ++    case OPT_fdiagnostics_column_origin_:
> ++      dc->column_origin = value;
> ++      break;
> ++
> +     case OPT_fdiagnostics_show_cwe:
> +       dc->show_cwe = value;
> +       break;
> +@@ -2825,6 +2833,12 @@ common_handle_option (struct gcc_options
> +       check_alignment_argument (loc, arg, "functions");
> +       break;
> +
> ++    case OPT_ftabstop_:
> ++      /* It is documented that we silently ignore silly values.  */
> ++      if (value >= 1 && value <= 100)
> ++      dc->tabstop = value;
> ++      break;
> ++
> +     default:
> +       /* If the flag was handled in a standard way, assume the lack
> of
> +        processing here is intentional.  */
> +diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-1.c
> b/gcc/testsuite/c-c++-common/diagnostic-format-json-1.c
> +--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-1.c    2020-
> 07-22 23:35:17.908390765 -0700
> ++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-1.c    2021-
> 12-25 01:20:53.487636494 -0800
> +@@ -8,17 +8,22 @@
> +    We can't rely on any ordering of the keys.  */
> +
> + /* { dg-regexp "\"kind\": \"error\"" } */
> ++/* { dg-regexp "\"column-origin\": 1" } */
> + /* { dg-regexp "\"message\": \"#error message\"" } */
> +
> + /* { dg-regexp "\"caret\": \{" } */
> + /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 1.c\"" } */
> + /* { dg-regexp "\"line\": 4" } */
> + /* { dg-regexp "\"column\": 2" } */
> ++/* { dg-regexp "\"display-column\": 2" } */
> ++/* { dg-regexp "\"byte-column\": 2" } */
> +
> + /* { dg-regexp "\"finish\": \{" } */
> + /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 1.c\"" } */
> + /* { dg-regexp "\"line\": 4" } */
> + /* { dg-regexp "\"column\": 6" } */
> ++/* { dg-regexp "\"display-column\": 6" } */
> ++/* { dg-regexp "\"byte-column\": 6" } */
> +
> + /* { dg-regexp "\"locations\": \[\[\{\}, \]*\]" } */
> + /* { dg-regexp "\"children\": \[\[\]\[\]\]" } */
> +diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-2.c
> b/gcc/testsuite/c-c++-common/diagnostic-format-json-2.c
> +--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-2.c    2020-
> 07-22 23:35:17.908390765 -0700
> ++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-2.c    2021-
> 12-25 01:20:53.487636494 -0800
> +@@ -8,6 +8,7 @@
> +    We can't rely on any ordering of the keys.  */
> +
> + /* { dg-regexp "\"kind\": \"warning\"" } */
> ++/* { dg-regexp "\"column-origin\": 1" } */
> + /* { dg-regexp "\"message\": \"#warning message\"" } */
> + /* { dg-regexp "\"option\": \"-Wcpp\"" } */
> + /* { dg-regexp "\"option_url\": \"https:\[^\n\r\"\]*#index-Wcpp\""
> } */
> +@@ -16,11 +17,15 @@
> + /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 2.c\"" } */
> + /* { dg-regexp "\"line\": 4" } */
> + /* { dg-regexp "\"column\": 2" } */
> ++/* { dg-regexp "\"display-column\": 2" } */
> ++/* { dg-regexp "\"byte-column\": 2" } */
> +
> + /* { dg-regexp "\"finish\": \{" } */
> + /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 2.c\"" } */
> + /* { dg-regexp "\"line\": 4" } */
> + /* { dg-regexp "\"column\": 8" } */
> ++/* { dg-regexp "\"display-column\": 8" } */
> ++/* { dg-regexp "\"byte-column\": 8" } */
> +
> + /* { dg-regexp "\"locations\": \[\[\{\}, \]*\]" } */
> + /* { dg-regexp "\"children\": \[\[\]\[\]\]" } */
> +diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-3.c
> b/gcc/testsuite/c-c++-common/diagnostic-format-json-3.c
> +--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-3.c    2020-
> 07-22 23:35:17.908390765 -0700
> ++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-3.c    2021-
> 12-25 01:20:53.487636494 -0800
> +@@ -8,6 +8,7 @@
> +    We can't rely on any ordering of the keys.  */
> +
> + /* { dg-regexp "\"kind\": \"error\"" } */
> ++/* { dg-regexp "\"column-origin\": 1" } */
> + /* { dg-regexp "\"message\": \"#warning message\"" } */
> + /* { dg-regexp "\"option\": \"-Werror=cpp\"" } */
> + /* { dg-regexp "\"option_url\": \"https:\[^\n\r\"\]*#index-Wcpp\""
> } */
> +@@ -16,11 +17,15 @@
> + /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 3.c\"" } */
> + /* { dg-regexp "\"line\": 4" } */
> + /* { dg-regexp "\"column\": 2" } */
> ++/* { dg-regexp "\"display-column\": 2" } */
> ++/* { dg-regexp "\"byte-column\": 2" } */
> +
> + /* { dg-regexp "\"finish\": \{" } */
> + /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 3.c\"" } */
> + /* { dg-regexp "\"line\": 4" } */
> + /* { dg-regexp "\"column\": 8" } */
> ++/* { dg-regexp "\"display-column\": 8" } */
> ++/* { dg-regexp "\"byte-column\": 8" } */
> +
> + /* { dg-regexp "\"locations\": \[\[\{\}, \]*\]" } */
> + /* { dg-regexp "\"children\": \[\[\]\[\]\]" } */
> +diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-4.c
> b/gcc/testsuite/c-c++-common/diagnostic-format-json-4.c
> +--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-4.c    2020-
> 07-22 23:35:17.908390765 -0700
> ++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-4.c    2021-
> 12-25 01:20:53.487636494 -0800
> +@@ -24,15 +24,20 @@ int test (void)
> + /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 4.c\"" } */
> + /* { dg-regexp "\"line\": 8" } */
> + /* { dg-regexp "\"column\": 5" } */
> ++/* { dg-regexp "\"display-column\": 5" } */
> ++/* { dg-regexp "\"byte-column\": 5" } */
> +
> + /* { dg-regexp "\"finish\": \{" } */
> + /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 4.c\"" } */
> + /* { dg-regexp "\"line\": 8" } */
> + /* { dg-regexp "\"column\": 10" } */
> ++/* { dg-regexp "\"display-column\": 10" } */
> ++/* { dg-regexp "\"byte-column\": 10" } */
> +
> + /* The outer diagnostic.  */
> +
> + /* { dg-regexp "\"kind\": \"warning\"" } */
> ++/* { dg-regexp "\"column-origin\": 1" } */
> + /* { dg-regexp "\"message\": \"this 'if' clause does not
> guard...\"" } */
> + /* { dg-regexp "\"option\": \"-Wmisleading-indentation\"" } */
> + /* { dg-regexp "\"option_url\": \"https:\[^\n\r\"\]*#index-
> Wmisleading-indentation\"" } */
> +@@ -41,11 +46,15 @@ int test (void)
> + /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 4.c\"" } */
> + /* { dg-regexp "\"line\": 6" } */
> + /* { dg-regexp "\"column\": 3" } */
> ++/* { dg-regexp "\"display-column\": 3" } */
> ++/* { dg-regexp "\"byte-column\": 3" } */
> +
> + /* { dg-regexp "\"finish\": \{" } */
> + /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 4.c\"" } */
> + /* { dg-regexp "\"line\": 6" } */
> + /* { dg-regexp "\"column\": 4" } */
> ++/* { dg-regexp "\"display-column\": 4" } */
> ++/* { dg-regexp "\"byte-column\": 4" } */
> +
> + /* More from the nested diagnostic (we can't guarantee what order
> the
> +    "file" keys are consumed).  */
> +diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-5.c
> b/gcc/testsuite/c-c++-common/diagnostic-format-json-5.c
> +--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-5.c    2020-
> 07-22 23:35:17.908390765 -0700
> ++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-5.c    2021-
> 12-25 01:20:53.487636494 -0800
> +@@ -13,6 +13,7 @@ int test (struct s *ptr)
> +    We can't rely on any ordering of the keys.  */
> +
> + /* { dg-regexp "\"kind\": \"error\"" } */
> ++/* { dg-regexp "\"column-origin\": 1" } */
> + /* { dg-regexp "\"message\": \".*\"" } */
> +
> + /* Verify fix-it hints.  */
> +@@ -23,11 +24,15 @@ int test (struct s *ptr)
> + /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 5.c\"" } */
> + /* { dg-regexp "\"line\": 8" } */
> + /* { dg-regexp "\"column\": 15" } */
> ++/* { dg-regexp "\"display-column\": 15" } */
> ++/* { dg-regexp "\"byte-column\": 15" } */
> +
> + /* { dg-regexp "\"next\": \{" } */
> + /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 5.c\"" } */
> + /* { dg-regexp "\"line\": 8" } */
> + /* { dg-regexp "\"column\": 21" } */
> ++/* { dg-regexp "\"display-column\": 21" } */
> ++/* { dg-regexp "\"byte-column\": 21" } */
> +
> + /* { dg-regexp "\"fixits\": \[\[\{\}, \]*\]" } */
> +
> +@@ -35,11 +40,15 @@ int test (struct s *ptr)
> + /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 5.c\"" } */
> + /* { dg-regexp "\"line\": 8" } */
> + /* { dg-regexp "\"column\": 15" } */
> ++/* { dg-regexp "\"display-column\": 15" } */
> ++/* { dg-regexp "\"byte-column\": 15" } */
> +
> + /* { dg-regexp "\"finish\": \{" } */
> + /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 5.c\"" } */
> + /* { dg-regexp "\"line\": 8" } */
> + /* { dg-regexp "\"column\": 20" } */
> ++/* { dg-regexp "\"display-column\": 20" } */
> ++/* { dg-regexp "\"byte-column\": 20" } */
> +
> + /* { dg-regexp "\"locations\": \[\[\{\}, \]*\]" } */
> + /* { dg-regexp "\"children\": \[\[\]\[\]\]" } */
> +diff --git a/gcc/testsuite/c-c++-common/diagnostic-units-1.c
> b/gcc/testsuite/c-c++-common/diagnostic-units-1.c
> +--- a/gcc/testsuite/c-c++-common/diagnostic-units-1.c  1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/diagnostic-units-1.c  2021-12-25
> 01:20:53.487636494 -0800
> +@@ -0,0 +1,28 @@
> ++/* { dg-do compile } */
> ++/* { dg-additional-options "-fdiagnostics-column-unit=byte -fshow-
> column -fdiagnostics-show-caret -Wmultichar" } */
> ++
> ++/* column units: bytes (via arg)
> ++   column origin: 1 (via default)
> ++   tabstop: 8 (via default) */
> ++
> ++/* This line starts with a tab.  */
> ++      int c1 = 'c1'; /* { dg-warning "11: multi-character character
> constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++         int c1 = 'c1';
> ++                  ^~~~
> ++   { dg-end-multiline-output "" } */
> ++
> ++/* This line starts with <tabstop> spaces.  */
> ++        int c2 = 'c2'; /* { dg-warning "18: multi-character
> character constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++         int c2 = 'c2';
> ++                  ^~~~
> ++   { dg-end-multiline-output "" } */
> ++
> ++/* This line starts with <tabstop> spaces and has an internal tab
> after
> ++   a space.  */
> ++        int c3 =      'c3'; /* { dg-warning "19: multi-character
> character constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++         int c3 =        'c3';
> ++                         ^~~~
> ++   { dg-end-multiline-output "" } */
> +diff --git a/gcc/testsuite/c-c++-common/diagnostic-units-2.c
> b/gcc/testsuite/c-c++-common/diagnostic-units-2.c
> +--- a/gcc/testsuite/c-c++-common/diagnostic-units-2.c  1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/diagnostic-units-2.c  2021-12-25
> 01:20:53.487636494 -0800
> +@@ -0,0 +1,28 @@
> ++/* { dg-do compile } */
> ++/* { dg-additional-options "-fdiagnostics-column-unit=display -
> fshow-column -fdiagnostics-show-caret -Wmultichar" } */
> ++
> ++/* column units: display (via arg)
> ++   column origin: 1 (via default)
> ++   tabstop: 8 (via default) */
> ++
> ++/* This line starts with a tab.  */
> ++      int c1 = 'c1'; /* { dg-warning "18: multi-character character
> constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++         int c1 = 'c1';
> ++                  ^~~~
> ++   { dg-end-multiline-output "" } */
> ++
> ++/* This line starts with <tabstop> spaces.  */
> ++        int c2 = 'c2'; /* { dg-warning "18: multi-character
> character constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++         int c2 = 'c2';
> ++                  ^~~~
> ++   { dg-end-multiline-output "" } */
> ++
> ++/* This line starts with <tabstop> spaces and has an internal tab
> after
> ++   a space.  */
> ++        int c3 =      'c3'; /* { dg-warning "25: multi-character
> character constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++         int c3 =        'c3';
> ++                         ^~~~
> ++   { dg-end-multiline-output "" } */
> +diff --git a/gcc/testsuite/c-c++-common/diagnostic-units-3.c
> b/gcc/testsuite/c-c++-common/diagnostic-units-3.c
> +--- a/gcc/testsuite/c-c++-common/diagnostic-units-3.c  1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/diagnostic-units-3.c  2021-12-25
> 01:20:53.487636494 -0800
> +@@ -0,0 +1,28 @@
> ++/* { dg-do compile } */
> ++/* { dg-additional-options "-fdiagnostics-column-unit=byte -fshow-
> column -fdiagnostics-show-caret -ftabstop=200 -Wmultichar" } */
> ++
> ++/* column units: bytes (via arg)
> ++   column origin: 1 (via fallback from overly large argument)
> ++   tabstop: 8 (via default) */
> ++
> ++/* This line starts with a tab.  */
> ++      int c1 = 'c1'; /* { dg-warning "11: multi-character character
> constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++         int c1 = 'c1';
> ++                  ^~~~
> ++   { dg-end-multiline-output "" } */
> ++
> ++/* This line starts with <tabstop> spaces.  */
> ++        int c2 = 'c2'; /* { dg-warning "18: multi-character
> character constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++         int c2 = 'c2';
> ++                  ^~~~
> ++   { dg-end-multiline-output "" } */
> ++
> ++/* This line starts with <tabstop> spaces and has an internal tab
> after
> ++   a space.  */
> ++        int c3 =      'c3'; /* { dg-warning "19: multi-character
> character constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++         int c3 =        'c3';
> ++                         ^~~~
> ++   { dg-end-multiline-output "" } */
> +diff --git a/gcc/testsuite/c-c++-common/diagnostic-units-4.c
> b/gcc/testsuite/c-c++-common/diagnostic-units-4.c
> +--- a/gcc/testsuite/c-c++-common/diagnostic-units-4.c  1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/diagnostic-units-4.c  2021-12-25
> 01:20:53.487636494 -0800
> +@@ -0,0 +1,28 @@
> ++/* { dg-do compile } */
> ++/* { dg-additional-options "-fdiagnostics-column-unit=byte -fshow-
> column -fdiagnostics-show-caret -fdiagnostics-column-origin=0 -
> Wmultichar" } */
> ++
> ++/* column units: bytes (via arg)
> ++   column origin: 0 (via arg)
> ++   tabstop: 8 (via default) */
> ++
> ++/* This line starts with a tab.  */
> ++      int c1 = 'c1'; /* { dg-warning "10: multi-character character
> constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++         int c1 = 'c1';
> ++                  ^~~~
> ++   { dg-end-multiline-output "" } */
> ++
> ++/* This line starts with <tabstop> spaces.  */
> ++        int c2 = 'c2'; /* { dg-warning "17: multi-character
> character constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++         int c2 = 'c2';
> ++                  ^~~~
> ++   { dg-end-multiline-output "" } */
> ++
> ++/* This line starts with <tabstop> spaces and has an internal tab
> after
> ++   a space.  */
> ++        int c3 =      'c3'; /* { dg-warning "18: multi-character
> character constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++         int c3 =        'c3';
> ++                         ^~~~
> ++   { dg-end-multiline-output "" } */
> +diff --git a/gcc/testsuite/c-c++-common/diagnostic-units-5.c
> b/gcc/testsuite/c-c++-common/diagnostic-units-5.c
> +--- a/gcc/testsuite/c-c++-common/diagnostic-units-5.c  1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/diagnostic-units-5.c  2021-12-25
> 01:20:53.491636427 -0800
> +@@ -0,0 +1,28 @@
> ++/* { dg-do compile } */
> ++/* { dg-additional-options "-fdiagnostics-column-unit=display -
> fshow-column -fdiagnostics-show-caret -fdiagnostics-column-origin=0 -
> Wmultichar" } */
> ++
> ++/* column units: display (via arg)
> ++   column origin: 0 (via arg)
> ++   tabstop: 8 (via default) */
> ++
> ++/* This line starts with a tab.  */
> ++      int c1 = 'c1'; /* { dg-warning "17: multi-character character
> constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++         int c1 = 'c1';
> ++                  ^~~~
> ++   { dg-end-multiline-output "" } */
> ++
> ++/* This line starts with <tabstop> spaces.  */
> ++        int c2 = 'c2'; /* { dg-warning "17: multi-character
> character constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++         int c2 = 'c2';
> ++                  ^~~~
> ++   { dg-end-multiline-output "" } */
> ++
> ++/* This line starts with <tabstop> spaces and has an internal tab
> after
> ++   a space.  */
> ++        int c3 =      'c3'; /* { dg-warning "24: multi-character
> character constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++         int c3 =        'c3';
> ++                         ^~~~
> ++   { dg-end-multiline-output "" } */
> +diff --git a/gcc/testsuite/c-c++-common/diagnostic-units-6.c
> b/gcc/testsuite/c-c++-common/diagnostic-units-6.c
> +--- a/gcc/testsuite/c-c++-common/diagnostic-units-6.c  1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/diagnostic-units-6.c  2021-12-25
> 01:20:53.491636427 -0800
> +@@ -0,0 +1,28 @@
> ++/* { dg-do compile } */
> ++/* { dg-additional-options "-fdiagnostics-column-unit=byte -fshow-
> column -fdiagnostics-show-caret -fdiagnostics-column-origin=100 -
> Wmultichar" } */
> ++
> ++/* column units: bytes (via arg)
> ++   column origin: 100 (via arg)
> ++   tabstop: 8 (via default) */
> ++
> ++/* This line starts with a tab.  */
> ++      int c1 = 'c1'; /* { dg-warning "110: multi-character
> character constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++         int c1 = 'c1';
> ++                  ^~~~
> ++   { dg-end-multiline-output "" } */
> ++
> ++/* This line starts with <tabstop> spaces.  */
> ++        int c2 = 'c2'; /* { dg-warning "117: multi-character
> character constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++         int c2 = 'c2';
> ++                  ^~~~
> ++   { dg-end-multiline-output "" } */
> ++
> ++/* This line starts with <tabstop> spaces and has an internal tab
> after
> ++   a space.  */
> ++        int c3 =      'c3'; /* { dg-warning "118: multi-character
> character constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++         int c3 =        'c3';
> ++                         ^~~~
> ++   { dg-end-multiline-output "" } */
> +diff --git a/gcc/testsuite/c-c++-common/diagnostic-units-7.c
> b/gcc/testsuite/c-c++-common/diagnostic-units-7.c
> +--- a/gcc/testsuite/c-c++-common/diagnostic-units-7.c  1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/diagnostic-units-7.c  2021-12-25
> 01:20:53.491636427 -0800
> +@@ -0,0 +1,28 @@
> ++/* { dg-do compile } */
> ++/* { dg-additional-options "-fdiagnostics-column-unit=byte -fshow-
> column -fdiagnostics-show-caret -ftabstop=9 -Wmultichar" } */
> ++
> ++/* column units: bytes (via arg)
> ++   column origin: 1 (via default)
> ++   tabstop: 9 (via arg) */
> ++
> ++/* This line starts with a tab.  */
> ++      int c1 = 'c1'; /* { dg-warning "11: multi-character character
> constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++          int c1 = 'c1';
> ++                   ^~~~
> ++   { dg-end-multiline-output "" } */
> ++
> ++/* This line starts with <tabstop> spaces.  */
> ++         int c2 = 'c2'; /* { dg-warning "19: multi-character
> character constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++          int c2 = 'c2';
> ++                   ^~~~
> ++   { dg-end-multiline-output "" } */
> ++
> ++/* This line starts with <tabstop> spaces and has an internal tab
> after
> ++   a space.  */
> ++         int c3 =     'c3'; /* { dg-warning "20: multi-character
> character constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++          int c3 =          'c3';
> ++                            ^~~~
> ++   { dg-end-multiline-output "" } */
> +diff --git a/gcc/testsuite/c-c++-common/diagnostic-units-8.c
> b/gcc/testsuite/c-c++-common/diagnostic-units-8.c
> +--- a/gcc/testsuite/c-c++-common/diagnostic-units-8.c  1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/diagnostic-units-8.c  2021-12-25
> 01:20:53.491636427 -0800
> +@@ -0,0 +1,28 @@
> ++/* { dg-do compile } */
> ++/* { dg-additional-options "-fshow-column -fdiagnostics-show-caret
> -ftabstop=9 -Wmultichar" } */
> ++
> ++/* column units: display (via default)
> ++   column origin: 1 (via default)
> ++   tabstop: 9 (via arg) */
> ++
> ++/* This line starts with a tab.  */
> ++      int c1 = 'c1'; /* { dg-warning "19: multi-character character
> constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++          int c1 = 'c1';
> ++                   ^~~~
> ++   { dg-end-multiline-output "" } */
> ++
> ++/* This line starts with <tabstop> spaces.  */
> ++         int c2 = 'c2'; /* { dg-warning "19: multi-character
> character constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++          int c2 = 'c2';
> ++                   ^~~~
> ++   { dg-end-multiline-output "" } */
> ++
> ++/* This line starts with <tabstop> spaces and has an internal tab
> after
> ++   a space.  */
> ++         int c3 =     'c3'; /* { dg-warning "28: multi-character
> character constant" } */
> ++/* { dg-begin-multiline-output "" }
> ++          int c3 =          'c3';
> ++                            ^~~~
> ++   { dg-end-multiline-output "" } */
> +diff --git a/gcc/testsuite/c-c++-common/missing-close-symbol.c
> b/gcc/testsuite/c-c++-common/missing-close-symbol.c
> +--- a/gcc/testsuite/c-c++-common/missing-close-symbol.c        2020-
> 07-22 23:35:17.912390810 -0700
> ++++ b/gcc/testsuite/c-c++-common/missing-close-symbol.c        2021-
> 12-25 01:20:53.491636427 -0800
> +@@ -24,9 +24,9 @@ void test_static_assert_different_line (
> +   _Static_assert(sizeof(int) >= sizeof(char), /* { dg-message "to
> match this '\\('" } */
> +                "msg"; /* { dg-error "expected '\\)' before ';'
> token" } */
> +   /* { dg-begin-multiline-output "" }
> +-    "msg";
> +-         ^
> +-         )
> ++                  "msg";
> ++                       ^
> ++                       )
> +      { dg-end-multiline-output "" } */
> +   /* { dg-begin-multiline-output "" }
> +    _Static_assert(sizeof(int) >= sizeof(char),
> +diff --git a/gcc/testsuite/c-c++-common/Wmisleading-indentation-3.c
> b/gcc/testsuite/c-c++-common/Wmisleading-indentation-3.c
> +--- a/gcc/testsuite/c-c++-common/Wmisleading-indentation-3.c   2020-
> 07-22 23:35:17.904390722 -0700
> ++++ b/gcc/testsuite/c-c++-common/Wmisleading-indentation-3.c   2021-
> 12-25 01:20:53.487636494 -0800
> +@@ -36,20 +36,20 @@ int fn_6 (int a, int b, int c)
> +       /* ... */
> +       if ((err = foo (a)) != 0)
> +               goto fail;
> +-      if ((err = foo (b)) != 0) /* { dg-message "2: this 'if'
> clause does not guard..." } */
> ++      if ((err = foo (b)) != 0) /* { dg-message "9: this 'if'
> clause does not guard..." } */
> +               goto fail;
> +-              goto fail; /* { dg-message "3: ...this statement, but
> the latter is misleadingly indented as if it were guarded by the
> 'if'" } */
> ++              goto fail; /* { dg-message "17: ...this statement,
> but the latter is misleadingly indented as if it were guarded by the
> 'if'" } */
> +       if ((err = foo (c)) != 0)
> +               goto fail;
> +       /* ... */
> +
> + /* { dg-begin-multiline-output "" }
> +-  if ((err = foo (b)) != 0)
> +-  ^~
> ++         if ((err = foo (b)) != 0)
> ++         ^~
> +    { dg-end-multiline-output "" } */
> + /* { dg-begin-multiline-output "" }
> +-   goto fail;
> +-   ^~~~
> ++                 goto fail;
> ++                 ^~~~
> +    { dg-end-multiline-output "" } */
> +
> + fail:
> +diff --git a/gcc/testsuite/c-c++-common/Wmisleading-indentation.c
> b/gcc/testsuite/c-c++-common/Wmisleading-indentation.c
> +--- a/gcc/testsuite/c-c++-common/Wmisleading-indentation.c     2020-
> 07-22 23:35:17.904390722 -0700
> ++++ b/gcc/testsuite/c-c++-common/Wmisleading-indentation.c     2021-
> 12-25 01:20:53.487636494 -0800
> +@@ -65,9 +65,9 @@ int fn_6 (int a, int b, int c)
> +       /* ... */
> +       if ((err = foo (a)) != 0)
> +               goto fail;
> +-      if ((err = foo (b)) != 0) /* { dg-message "2: this 'if'
> clause does not guard..." } */
> ++      if ((err = foo (b)) != 0) /* { dg-message "9: this 'if'
> clause does not guard..." } */
> +               goto fail;
> +-              goto fail; /* { dg-message "3: ...this statement, but
> the latter is misleadingly indented as if it were guarded by the
> 'if'" } */
> ++              goto fail; /* { dg-message "17: ...this statement,
> but the latter is misleadingly indented as if it were guarded by the
> 'if'" } */
> +       if ((err = foo (c)) != 0)
> +               goto fail;
> +       /* ... */
> +@@ -178,7 +178,7 @@ void fn_16_tabs (void)
> +     while (flagA)
> +       if (flagB) /* { dg-message "7: this 'if' clause does not
> guard..." } */
> +       foo (0);
> +-      foo (1);/* { dg-message "2: ...this statement, but the latter
> is misleadingly indented as if it were guarded by the 'if'" } */
> ++      foo (1);/* { dg-message "9: ...this statement, but the latter
> is misleadingly indented as if it were guarded by the 'if'" } */
> + }
> +
> + void fn_17_spaces (void)
> +diff --git a/gcc/testsuite/gcc.dg/analyzer/malloc-paths-9.c
> b/gcc/testsuite/gcc.dg/analyzer/malloc-paths-9.c
> +--- a/gcc/testsuite/gcc.dg/analyzer/malloc-paths-9.c   2020-07-22
> 23:35:18.124393144 -0700
> ++++ b/gcc/testsuite/gcc.dg/analyzer/malloc-paths-9.c   2021-12-25
> 01:20:53.491636427 -0800
> +@@ -288,7 +288,7 @@ int test_3 (int x, int y)
> +     |      |     ~~~~~~~~~~
> +     |      |     |
> +     |      |     (4) ...to here
> +-    |   NN |      to dereference it above
> ++    |   NN |                    to dereference it above
> +     |   NN |   return *ptr;
> +     |      |          ~~~~
> +     |      |          |
> +diff --git a/gcc/testsuite/gcc.dg/bad-binary-ops.c
> b/gcc/testsuite/gcc.dg/bad-binary-ops.c
> +--- a/gcc/testsuite/gcc.dg/bad-binary-ops.c    2020-07-22
> 23:35:18.128393190 -0700
> ++++ b/gcc/testsuite/gcc.dg/bad-binary-ops.c    2021-12-25
> 01:20:53.491636427 -0800
> +@@ -35,10 +35,10 @@ int test_2 (void)
> +            ~~~~~~~~~~~~~~~~
> +            |
> +            struct s
> +-    + some_other_function ());
> +-    ^ ~~~~~~~~~~~~~~~~~~~~~~
> +-      |
> +-      struct t
> ++           + some_other_function ());
> ++           ^ ~~~~~~~~~~~~~~~~~~~~~~
> ++             |
> ++             struct t
> +    { dg-end-multiline-output "" } */
> + }
> +
> +diff --git a/gcc/testsuite/gcc.dg/format/branch-1.c
> b/gcc/testsuite/gcc.dg/format/branch-1.c
> +--- a/gcc/testsuite/gcc.dg/format/branch-1.c   2020-07-22
> 23:35:18.152393454 -0700
> ++++ b/gcc/testsuite/gcc.dg/format/branch-1.c   2021-12-25
> 01:20:53.491636427 -0800
> +@@ -10,7 +10,7 @@ foo (long l, int nfoo)
> + {
> +   printf ((nfoo > 1) ? "%d foos" : "%d foo", nfoo);
> +   printf ((l > 1) ? "%d foos" /* { dg-warning "23:int" "wrong type
> in conditional expr" } */
> +-                : "%d foo", l); /* { dg-warning "16:int" "wrong
> type in conditional expr" } */
> ++                : "%d foo", l); /* { dg-warning "23:int" "wrong
> type in conditional expr" } */
> +   printf ((l > 1) ? "%ld foos" : "%d foo", l); /* { dg-warning
> "36:int" "wrong type in conditional expr" } */
> +   printf ((l > 1) ? "%d foos" : "%ld foo", l); /* { dg-warning
> "23:int" "wrong type in conditional expr" } */
> +   /* Should allow one case to have extra arguments.  */
> +diff --git a/gcc/testsuite/gcc.dg/format/pr79210.c
> b/gcc/testsuite/gcc.dg/format/pr79210.c
> +--- a/gcc/testsuite/gcc.dg/format/pr79210.c    2020-07-22
> 23:35:18.152393454 -0700
> ++++ b/gcc/testsuite/gcc.dg/format/pr79210.c    2021-12-25
> 01:20:53.491636427 -0800
> +@@ -20,4 +20,4 @@ LPFC_VPORT_ATTR_R(peer_port_login,
> +                 "Allow peer ports on the same physical port to
> login to each "
> +                 "other.");
> +
> +-/* { dg-warning "6: format .%d. expects argument of type .int., but
> argument 4 has type .unsigned int. " "" { target *-*-* } .-12 } */
> ++/* { dg-warning "20: format .%d. expects argument of type .int.,
> but argument 4 has type .unsigned int. " "" { target *-*-* } .-12 }
> */
> +diff --git a/gcc/testsuite/gcc.dg/plugin/diagnostic-test-
> expressions-1.c b/gcc/testsuite/gcc.dg/plugin/diagnostic-test-
> expressions-1.c
> +--- a/gcc/testsuite/gcc.dg/plugin/diagnostic-test-expressions-
> 1.c      2020-07-22 23:35:18.172393674 -0700
> ++++ b/gcc/testsuite/gcc.dg/plugin/diagnostic-test-expressions-
> 1.c      2021-12-25 01:20:53.491636427 -0800
> +@@ -540,15 +540,15 @@ void test_builtin_types_compatible_p (un
> +   __emit_expression_range (0,
> +                          f (i) + __builtin_types_compatible_p
> (long, int)); /* { dg-warning "range" } */
> + /* { dg-begin-multiline-output "" }
> +-       f (i) + __builtin_types_compatible_p (long, int));
> +-       ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ++                            f (i) + __builtin_types_compatible_p
> (long, int));
> ++
> ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +    { dg-end-multiline-output "" } */
> +
> +   __emit_expression_range (0,
> +                          __builtin_types_compatible_p (long, int) +
> f (i)); /* { dg-warning "range" } */
> + /* { dg-begin-multiline-output "" }
> +-       __builtin_types_compatible_p (long, int) + f (i));
> +-       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
> ++                            __builtin_types_compatible_p (long,
> int) + f (i));
> ++
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
> +    { dg-end-multiline-output "" } */
> + }
> +
> +@@ -671,8 +671,8 @@ void test_multiple_ordinary_maps (void)
> + /* { dg-begin-multiline-output "" }
> +    __emit_expression_range (0, foo (0,
> +                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +-
> "01234567890123456789012345678901234567890123456789012345678901234567
> 89012345678901234567890123456789012345678901234567890123456789"));
> +-
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ++
> "01234567890123456789012345678901234567890123456789012345678901234567
> 89012345678901234567890123456789012345678901234567890123456789"));
> ++
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +    { dg-end-multiline-output "" } */
> +
> +   /* Another expression that transitions between ordinary maps;
> this
> +@@ -685,8 +685,8 @@ void test_multiple_ordinary_maps (void)
> + /* { dg-begin-multiline-output "" }
> +    __emit_expression_range (0, foo (0,
> "01234567890123456789012345678901234567890123456789012345678901234567
> 890123456789012345678901234567890123456789012345678901234567890123456
> 789012345678901234567890123456789012345678901234567890123456789012345
> 678901234567890123456789012345678901234567890123456789012345678901234
> 567890123456789012345678901234567890123456789012345678901234567890123
> 456789012345678901234567890123456789012345678901234567890123456789012
> 345678901234567890123456789012345678901234567890123456789012345678901
> 234567890123456789012345678901234567890123456789012345678901234567890
> 123456789012345678901234567890123456789012345678901234567890123456789
> 012345678901234567890123456789012345678901234567890123456789012345678
> 901234567890123456789012345678901234567890123456789012345678901234567
> 890123456789012345678901234567890123456789012345678901234567890123456
> 789012345678901234567890123456789012345678901234567890123456789012345
> 678901234567890123456789012345678901234567890123456789012345678901234
> 567890123456789012345678901234567890123456789012345678901234567890123
> 456789012345678901234567890123456789012345678901234567890123456789012
> 345678901234567890123456789012345678901234567890123456789012345678901
> 234567890123456789012345678901234567890123456789012345678901234567890
> 123456789012345678901234567890123456789012345678901234567890123456789
> 012345678901234567890123456789012345678901234567890123456789012345678
> 901234567890123456789012345678901234567890123456789012345678901234567
> 890123456789012345678901234567890123456789012345678901234567890123456
> 789012345678901234567890123456789012345678901234567890123456789012345
> 678901234567890123456789012345678901234567890123456789012345678901234
> 567890123456789012345678901234567890123456789012345678901234567890123
> 456789012345678901234567890123456789012345678901234567890123456789012
> 345678901234567890123456789012345678901234567890123456789012345678901
> 234567890123456789012345678901234567890123456789012345678901234567890
> 123456789012345678901234567890123456789012345678901234567890123456789
> 012345678901234567890123456789012345678901234567890123456789012345678
> 901234567890123456789",
> +
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +-        0));
> +-        ~~
> ++                                    0));
> ++                                    ~~
> +    { dg-end-multiline-output "" } */
> + }
> +
> +diff --git a/gcc/testsuite/gcc.dg/plugin/diagnostic-test-string-
> literals-1.c b/gcc/testsuite/gcc.dg/plugin/diagnostic-test-string-
> literals-1.c
> +--- a/gcc/testsuite/gcc.dg/plugin/diagnostic-test-string-literals-
> 1.c  2020-07-22 23:35:18.172393674 -0700
> ++++ b/gcc/testsuite/gcc.dg/plugin/diagnostic-test-string-literals-
> 1.c  2021-12-25 01:20:53.491636427 -0800
> +@@ -335,11 +335,11 @@ pr87652 (const char *stem, int counter)
> + /* { dg-error "unable to read substring location: unable to read
> source line" "" { target c } 329 } */
> + /* { dg-error "unable to read substring location: failed to get
> ordinary maps" "" { target c++ } 329 } */
> + /* { dg-begin-multiline-output "" }
> +-     __emit_string_literal_range(__FILE__":%5d: " format, \
> ++     __emit_string_literal_range(__FILE__":%5d: " format,        \
> +                                  ^~~~~~~~
> +      { dg-end-multiline-output "" { target c } } */
> + /* { dg-begin-multiline-output "" }
> +-     __emit_string_literal_range(__FILE__":%5d: " format, \
> ++     __emit_string_literal_range(__FILE__":%5d: " format,        \
> +                                  ^
> +      { dg-end-multiline-output "" { target c++ } } */
> +
> +diff --git a/gcc/testsuite/gcc.dg/redecl-4.c
> b/gcc/testsuite/gcc.dg/redecl-4.c
> +--- a/gcc/testsuite/gcc.dg/redecl-4.c  2020-07-22 23:35:18.192393895
> -0700
> ++++ b/gcc/testsuite/gcc.dg/redecl-4.c  2021-12-25 01:20:53.491636427
> -0800
> +@@ -15,7 +15,7 @@ f (void)
> +     /* Should get format warnings even though the built-in
> declaration
> +        isn't "visible".  */
> +     printf (
> +-          "%s", 1); /* { dg-warning "8:format" } */
> ++          "%s", 1); /* { dg-warning "15:format" } */
> +     /* The type of strcmp here should have no prototype.  */
> +     if (0)
> +       strcmp (1);
> +diff --git a/gcc/testsuite/g++.dg/diagnostic/bad-binary-ops.C
> b/gcc/testsuite/g++.dg/diagnostic/bad-binary-ops.C
> +--- a/gcc/testsuite/g++.dg/diagnostic/bad-binary-ops.C 2020-07-22
> 23:35:17.972391472 -0700
> ++++ b/gcc/testsuite/g++.dg/diagnostic/bad-binary-ops.C 2021-12-25
> 01:20:53.491636427 -0800
> +@@ -33,10 +33,10 @@ int test_2 (void)
> +            ~~~~~~~~~~~~~~~~
> +                          |
> +                          s
> +-    + some_other_function ());
> +-    ^ ~~~~~~~~~~~~~~~~~~~~~~
> +-                          |
> +-                          t
> ++           + some_other_function ());
> ++           ^ ~~~~~~~~~~~~~~~~~~~~~~
> ++                                 |
> ++                                 t
> +    { dg-end-multiline-output "" } */
> + }
> +
> +diff --git a/gcc/testsuite/g++.dg/parse/error4.C
> b/gcc/testsuite/g++.dg/parse/error4.C
> +--- a/gcc/testsuite/g++.dg/parse/error4.C      2020-07-22
> 23:35:18.012391910 -0700
> ++++ b/gcc/testsuite/g++.dg/parse/error4.C      2021-12-25
> 01:20:53.491636427 -0800
> +@@ -7,4 +7,4 @@ struct X {
> +                int);
> + };
> +
> +-// { dg-error "4:'itn' has not been declared" "" { target *-*-* } 6
> }
> ++// { dg-error "18:'itn' has not been declared" "" { target *-*-* }
> 6 }
> +diff --git a/gcc/testsuite/gfortran.dg/diagnostic-format-json-1.F90
> b/gcc/testsuite/gfortran.dg/diagnostic-format-json-1.F90
> +--- a/gcc/testsuite/gfortran.dg/diagnostic-format-json-1.F90   2020-
> 07-22 23:35:18.512397420 -0700
> ++++ b/gcc/testsuite/gfortran.dg/diagnostic-format-json-1.F90   2021-
> 12-25 01:20:53.491636427 -0800
> +@@ -8,17 +8,22 @@
> + ! We can't rely on any ordering of the keys.
> +
> + ! { dg-regexp "\"kind\": \"error\"" }
> ++! { dg-regexp "\"column-origin\": 1" }
> + ! { dg-regexp "\"message\": \"#error message\"" }
> +
> + ! { dg-regexp "\"caret\": \{" }
> + ! { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 1.F90\"" }
> + ! { dg-regexp "\"line\": 4" }
> + ! { dg-regexp "\"column\": 2" }
> ++! { dg-regexp "\"display-column\": 2" }
> ++! { dg-regexp "\"byte-column\": 2" }
> +
> + ! { dg-regexp "\"finish\": \{" }
> + ! { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 1.F90\"" }
> + ! { dg-regexp "\"line\": 4" }
> + ! { dg-regexp "\"column\": 6" }
> ++! { dg-regexp "\"display-column\": 6" }
> ++! { dg-regexp "\"byte-column\": 6" }
> +
> + ! { dg-regexp "\"locations\": \[\[\{\}, \]*\]" }
> + ! { dg-regexp "\"children\": \[\[\]\[\]\]" }
> +diff --git a/gcc/testsuite/gfortran.dg/diagnostic-format-json-2.F90
> b/gcc/testsuite/gfortran.dg/diagnostic-format-json-2.F90
> +--- a/gcc/testsuite/gfortran.dg/diagnostic-format-json-2.F90   2020-
> 07-22 23:35:18.512397420 -0700
> ++++ b/gcc/testsuite/gfortran.dg/diagnostic-format-json-2.F90   2021-
> 12-25 01:20:53.491636427 -0800
> +@@ -8,6 +8,7 @@
> + ! We can't rely on any ordering of the keys.
> +
> + ! { dg-regexp "\"kind\": \"warning\"" }
> ++! { dg-regexp "\"column-origin\": 1" }
> + ! { dg-regexp "\"message\": \"#warning message\"" }
> + ! { dg-regexp "\"option\": \"-Wcpp\"" }
> + ! { dg-regexp "\"option_url\": \"\[^\n\r\"\]*#index-Wcpp\"" }
> +@@ -16,11 +17,15 @@
> + ! { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 2.F90\"" }
> + ! { dg-regexp "\"line\": 4" }
> + ! { dg-regexp "\"column\": 2" }
> ++! { dg-regexp "\"display-column\": 2" }
> ++! { dg-regexp "\"byte-column\": 2" }
> +
> + ! { dg-regexp "\"finish\": \{" }
> + ! { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 2.F90\"" }
> + ! { dg-regexp "\"line\": 4" }
> + ! { dg-regexp "\"column\": 8" }
> ++! { dg-regexp "\"display-column\": 8" }
> ++! { dg-regexp "\"byte-column\": 8" }
> +
> + ! { dg-regexp "\"locations\": \[\[\{\}, \]*\]" }
> + ! { dg-regexp "\"children\": \[\[\]\[\]\]" }
> +diff --git a/gcc/testsuite/gfortran.dg/diagnostic-format-json-3.F90
> b/gcc/testsuite/gfortran.dg/diagnostic-format-json-3.F90
> +--- a/gcc/testsuite/gfortran.dg/diagnostic-format-json-3.F90   2020-
> 07-22 23:35:18.512397420 -0700
> ++++ b/gcc/testsuite/gfortran.dg/diagnostic-format-json-3.F90   2021-
> 12-25 01:20:53.491636427 -0800
> +@@ -8,6 +8,7 @@
> + ! We can't rely on any ordering of the keys.
> +
> + ! { dg-regexp "\"kind\": \"error\"" }
> ++! { dg-regexp "\"column-origin\": 1" }
> + ! { dg-regexp "\"message\": \"#warning message\"" }
> + ! { dg-regexp "\"option\": \"-Werror=cpp\"" }
> + ! { dg-regexp "\"option_url\": \"\[^\n\r\"\]*#index-Wcpp\"" }
> +@@ -16,11 +17,15 @@
> + ! { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 3.F90\"" }
> + ! { dg-regexp "\"line\": 4" }
> + ! { dg-regexp "\"column\": 2" }
> ++! { dg-regexp "\"display-column\": 2" }
> ++! { dg-regexp "\"byte-column\": 2" }
> +
> + ! { dg-regexp "\"finish\": \{" }
> + ! { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 3.F90\"" }
> + ! { dg-regexp "\"line\": 4" }
> + ! { dg-regexp "\"column\": 8" }
> ++! { dg-regexp "\"display-column\": 8" }
> ++! { dg-regexp "\"byte-column\": 8" }
> +
> + ! { dg-regexp "\"locations\": \[\[\{\}, \]*\]" }
> + ! { dg-regexp "\"children\": \[\[\]\[\]\]" }
> +diff --git a/gcc/testsuite/go.dg/arrayclear.go
> b/gcc/testsuite/go.dg/arrayclear.go
> +--- a/gcc/testsuite/go.dg/arrayclear.go        2020-07-22
> 23:35:18.588398257 -0700
> ++++ b/gcc/testsuite/go.dg/arrayclear.go        2021-12-25
> 01:20:53.491636427 -0800
> +@@ -1,5 +1,8 @@
> + // { dg-do compile }
> + // { dg-options "-fgo-debug-optimization" }
> ++// This comment is necessary to work around a dejagnu bug.
> Otherwise, the
> ++// column of the second error message would equal the row of the
> first one, and
> ++// since the errors are also identical, dejagnu is not able to
> distinguish them.
> +
> + package p
> +
> +diff --git a/gcc/testsuite/g++.old-deja/g++.brendan/crash11.C
> b/gcc/testsuite/g++.old-deja/g++.brendan/crash11.C
> +--- a/gcc/testsuite/g++.old-deja/g++.brendan/crash11.C 2020-07-22
> 23:35:18.048392308 -0700
> ++++ b/gcc/testsuite/g++.old-deja/g++.brendan/crash11.C 2021-12-25
> 01:20:53.491636427 -0800
> +@@ -9,13 +9,13 @@ class A {
> +       int     h;
> +       A() { i=10; j=20; }
> +       virtual void f1() { printf("i=%d j=%d\n",i,j); }
> +-      friend virtual void f2() { printf("i=%d j=%d\n",i,j); } // {
> dg-error "9:virtual functions cannot be friends" }
> ++      friend virtual void f2() { printf("i=%d j=%d\n",i,j); } // {
> dg-error "16:virtual functions cannot be friends" }
> + };
> +
> + class B : public A {
> +     public:
> +       virtual void f1() { printf("i=%d j=%d\n",i,j); }// { dg-error
> "" }  member.*// ERROR -  member.*
> +-      friend virtual void f2() { printf("i=%d j=%d\n",i,j); }  // {
> dg-error "9:virtual functions cannot be friends" }
> ++      friend virtual void f2() { printf("i=%d j=%d\n",i,j); }  // {
> dg-error "16:virtual functions cannot be friends" }
> + // { dg-error "private" "" { target *-*-* } .-1 }
> + };
> +
> +diff --git a/gcc/testsuite/g++.old-deja/g++.pt/overload2.C
> b/gcc/testsuite/g++.old-deja/g++.pt/overload2.C
> +--- a/gcc/testsuite/g++.old-deja/g++.pt/overload2.C    2020-07-22
> 23:35:18.072392572 -0700
> ++++ b/gcc/testsuite/g++.old-deja/g++.pt/overload2.C    2021-12-25
> 01:20:53.491636427 -0800
> +@@ -12,5 +12,5 @@ int
> + main()
> + {
> +       C<char*>        c;
> +-      char*           p = Z(c.O); //{ dg-error "13:'Z' was not
> declared" } ambiguous c.O
> ++      char*           p = Z(c.O); //{ dg-error "29:'Z' was not
> declared" } ambiguous c.O
> + }
> +diff --git a/gcc/testsuite/g++.old-deja/g++.robertl/eb109.C
> b/gcc/testsuite/g++.old-deja/g++.robertl/eb109.C
> +--- a/gcc/testsuite/g++.old-deja/g++.robertl/eb109.C   2020-07-22
> 23:35:18.076392617 -0700
> ++++ b/gcc/testsuite/g++.old-deja/g++.robertl/eb109.C   2021-12-25
> 01:20:53.491636427 -0800
> +@@ -48,8 +48,8 @@ ostream& operator<<(ostream& os, Graph<V
> +
> +         // The compiler does not like this line!!!!!!
> +         typename Graph<VertexType, EdgeType>::Successor::iterator
> +-        startN = G[i].second.begin(), // { dg-error "14:no match" }
> no index operator
> +-        endN   = G[i].second.end();  // { dg-error "14:no match" }
> no index operator
> ++        startN = G[i].second.begin(), // { dg-error "21:no match" }
> no index operator
> ++        endN   = G[i].second.end();  // { dg-error "21:no match" }
> no index operator
> +
> +         while(startN != endN)
> +         {
> +diff --git a/gcc/tree-diagnostic-path.cc b/gcc/tree-diagnostic-
> path.cc
> +--- a/gcc/tree-diagnostic-path.cc      2020-07-22 23:35:18.628398698
> -0700
> ++++ b/gcc/tree-diagnostic-path.cc      2021-12-25 01:20:53.491636427
> -0800
> +@@ -493,7 +493,7 @@ default_tree_diagnostic_path_printer (di
> +    doesn't have access to trees (for m_fndecl).  */
> +
> + json::value *
> +-default_tree_make_json_for_path (diagnostic_context *,
> ++default_tree_make_json_for_path (diagnostic_context *context,
> +                                const diagnostic_path *path)
> + {
> +   json::array *path_array = new json::array ();
> +@@ -504,7 +504,8 @@ default_tree_make_json_for_path (diagnos
> +       json::object *event_obj = new json::object ();
> +       if (event.get_location ())
> +       event_obj->set ("location",
> +-                      json_from_expanded_location
> (event.get_location ()));
> ++                      json_from_expanded_location (context,
> ++
> event.get_location ()));
> +       label_text event_text (event.get_desc (false));
> +       event_obj->set ("description", new json::string
> (event_text.m_buffer));
> +       event_text.maybe_free ();
> +diff --git a/libcpp/charset.c b/libcpp/charset.c
> +--- a/libcpp/charset.c 2020-07-22 23:35:18.712399623 -0700
> ++++ b/libcpp/charset.c 2021-12-25 01:20:53.491636427 -0800
> +@@ -2276,49 +2276,90 @@ cpp_string_location_reader::get_next ()
> +   return result;
> + }
> +
> +-/* Helper for cpp_byte_column_to_display_column and its inverse.
> Given a
> +-   pointer to a UTF-8-encoded character, compute its display
> width.  *INBUFP
> +-   points on entry to the start of the UTF-8 encoding of the
> character, and
> +-   is updated to point just after the last byte of the encoding.
> *INBYTESLEFTP
> +-   contains on entry the remaining size of the buffer into which
> *INBUFP
> +-   points, and this is also updated accordingly.  If *INBUFP does
> not
> ++cpp_display_width_computation::
> ++cpp_display_width_computation (const char *data, int data_length,
> int tabstop) :
> ++  m_begin (data),
> ++  m_next (m_begin),
> ++  m_bytes_left (data_length),
> ++  m_tabstop (tabstop),
> ++  m_display_cols (0)
> ++{
> ++  gcc_assert (m_tabstop > 0);
> ++}
> ++
> ++
> ++/* The main implementation function for class
> cpp_display_width_computation.
> ++   m_next points on entry to the start of the UTF-8 encoding of the
> next
> ++   character, and is updated to point just after the last byte of
> the encoding.
> ++   m_bytes_left contains on entry the remaining size of the buffer
> into which
> ++   m_next points, and this is also updated accordingly.  If m_next
> does not
> +    point to a valid UTF-8-encoded sequence, then it will be treated
> as a single
> +-   byte with display width 1.  */
> ++   byte with display width 1.  m_cur_display_col is the current
> display column,
> ++   relative to which tab stops should be expanded.  Returns the
> display width of
> ++   the codepoint just processed.  */
> +
> +-static inline int
> +-compute_next_display_width (const uchar **inbufp, size_t
> *inbytesleftp)
> ++int
> ++cpp_display_width_computation::process_next_codepoint ()
> + {
> +   cppchar_t c;
> +-  if (one_utf8_to_cppchar (inbufp, inbytesleftp, &c) != 0)
> ++  int next_width;
> ++
> ++  if (*m_next == '\t')
> ++    {
> ++      ++m_next;
> ++      --m_bytes_left;
> ++      next_width = m_tabstop - (m_display_cols % m_tabstop);
> ++    }
> ++  else if (one_utf8_to_cppchar ((const uchar **) &m_next,
> &m_bytes_left, &c)
> ++         != 0)
> +     {
> +       /* Input is not convertible to UTF-8.  This could be fine,
> e.g. in a
> +        string literal, so don't complain.  Just treat it as if it
> has a width
> +        of one.  */
> +-      ++*inbufp;
> +-      --*inbytesleftp;
> +-      return 1;
> ++      ++m_next;
> ++      --m_bytes_left;
> ++      next_width = 1;
> ++    }
> ++  else
> ++    {
> ++      /*  one_utf8_to_cppchar() has updated m_next and m_bytes_left
> for us.  */
> ++      next_width = cpp_wcwidth (c);
> +     }
> +
> +-  /*  one_utf8_to_cppchar() has updated inbufp and inbytesleftp for
> us.  */
> +-  return cpp_wcwidth (c);
> ++  m_display_cols += next_width;
> ++  return next_width;
> ++}
> ++
> ++/*  Utility to advance the byte stream by the minimum amount needed
> to consume
> ++    N display columns.  Returns the number of display columns that
> were
> ++    actually skipped.  This could be less than N, if there was not
> enough data,
> ++    or more than N, if the last character to be skipped had a
> sufficiently large
> ++    display width.  */
> ++int
> ++cpp_display_width_computation::advance_display_cols (int n)
> ++{
> ++  const int start = m_display_cols;
> ++  const int target = start + n;
> ++  while (m_display_cols < target && !done ())
> ++    process_next_codepoint ();
> ++  return m_display_cols - start;
> + }
> +
> + /*  For the string of length DATA_LENGTH bytes that begins at DATA,
> compute
> +     how many display columns are occupied by the first COLUMN
> bytes.  COLUMN
> +     may exceed DATA_LENGTH, in which case the phantom bytes at the
> end are
> +-    treated as if they have display width 1.  */
> ++    treated as if they have display width 1.  Tabs are expanded to
> the next tab
> ++    stop, relative to the start of DATA.  */
> +
> + int
> + cpp_byte_column_to_display_column (const char *data, int
> data_length,
> +-                                 int column)
> ++                                 int column, int tabstop)
> + {
> +-  int display_col = 0;
> +-  const uchar *udata = (const uchar *) data;
> +   const int offset = MAX (0, column - data_length);
> +-  size_t inbytesleft = column - offset;
> +-  while (inbytesleft)
> +-    display_col += compute_next_display_width (&udata,
> &inbytesleft);
> +-  return display_col + offset;
> ++  cpp_display_width_computation dw (data, column - offset,
> tabstop);
> ++  while (!dw.done ())
> ++    dw.process_next_codepoint ();
> ++  return dw.display_cols_processed () + offset;
> + }
> +
> + /*  For the string of length DATA_LENGTH bytes that begins at DATA,
> compute
> +@@ -2328,14 +2369,11 @@ cpp_byte_column_to_display_column (const
> +
> + int
> + cpp_display_column_to_byte_column (const char *data, int
> data_length,
> +-                                 int display_col)
> ++                                 int display_col, int tabstop)
> + {
> +-  int column = 0;
> +-  const uchar *udata = (const uchar *) data;
> +-  size_t inbytesleft = data_length;
> +-  while (column < display_col && inbytesleft)
> +-      column += compute_next_display_width (&udata, &inbytesleft);
> +-  return data_length - inbytesleft + MAX (0, display_col - column);
> ++  cpp_display_width_computation dw (data, data_length, tabstop);
> ++  const int avail_display = dw.advance_display_cols (display_col);
> ++  return dw.bytes_processed () + MAX (0, display_col -
> avail_display);
> + }
> +
> + /* Our own version of wcwidth().  We don't use the actual wcwidth()
> in glibc,
> +diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
> +--- a/libcpp/include/cpplib.h  2020-07-22 23:35:18.712399623 -0700
> ++++ b/libcpp/include/cpplib.h  2021-12-25 01:20:53.491636427 -0800
> +@@ -312,9 +312,6 @@ enum cpp_normalize_level {
> +    carries all the options visible to the command line.  */
> + struct cpp_options
> + {
> +-  /* Characters between tab stops.  */
> +-  unsigned int tabstop;
> +-
> +   /* The language we're preprocessing.  */
> +   enum c_lang lang;
> +
> +@@ -1322,14 +1319,43 @@ extern const char * cpp_get_userdef_suff
> +   (const cpp_token *);
> +
> + /* In charset.c */
> ++
> ++/* A class to manage the state while converting a UTF-8 sequence to
> cppchar_t
> ++   and computing the display width one character at a time.  */
> ++class cpp_display_width_computation {
> ++ public:
> ++  cpp_display_width_computation (const char *data, int data_length,
> ++                               int tabstop);
> ++  const char *next_byte () const { return m_next; }
> ++  int bytes_processed () const { return m_next - m_begin; }
> ++  int bytes_left () const { return m_bytes_left; }
> ++  bool done () const { return !bytes_left (); }
> ++  int display_cols_processed () const { return m_display_cols; }
> ++
> ++  int process_next_codepoint ();
> ++  int advance_display_cols (int n);
> ++
> ++ private:
> ++  const char *const m_begin;
> ++  const char *m_next;
> ++  size_t m_bytes_left;
> ++  const int m_tabstop;
> ++  int m_display_cols;
> ++};
> ++
> ++/* Convenience functions that are simple use cases for class
> ++   cpp_display_width_computation.  Tab characters will be expanded
> to spaces
> ++   as determined by TABSTOP.  */
> + int cpp_byte_column_to_display_column (const char *data, int
> data_length,
> +-                                     int column);
> +-inline int cpp_display_width (const char *data, int data_length)
> ++                                     int column, int tabstop);
> ++inline int cpp_display_width (const char *data, int data_length,
> ++                            int tabstop)
> + {
> +-    return cpp_byte_column_to_display_column (data, data_length,
> data_length);
> ++  return cpp_byte_column_to_display_column (data, data_length,
> data_length,
> ++                                          tabstop);
> + }
> + int cpp_display_column_to_byte_column (const char *data, int
> data_length,
> +-                                     int display_col);
> ++                                     int display_col, int tabstop);
> + int cpp_wcwidth (cppchar_t c);
> +
> + #endif /* ! LIBCPP_CPPLIB_H */
> +diff --git a/libcpp/init.c b/libcpp/init.c
> +--- a/libcpp/init.c    2020-07-22 23:35:18.712399623 -0700
> ++++ b/libcpp/init.c    2021-12-25 01:20:53.491636427 -0800
> +@@ -190,7 +190,6 @@ cpp_create_reader (enum c_lang lang, cpp
> +   CPP_OPTION (pfile, discard_comments) = 1;
> +   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
> +   CPP_OPTION (pfile, max_include_depth) = 200;
> +-  CPP_OPTION (pfile, tabstop) = 8;
> +   CPP_OPTION (pfile, operator_names) = 1;
> +   CPP_OPTION (pfile, warn_trigraphs) = 2;
> +   CPP_OPTION (pfile, warn_endif_labels) = 1;
> diff --git a/meta/recipes-devtools/gcc/gcc/0002-CVE-2021-42574.patch
> b/meta/recipes-devtools/gcc/gcc/0002-CVE-2021-42574.patch
> new file mode 100644
> index 0000000000..5b1896ed69
> --- /dev/null
> +++ b/meta/recipes-devtools/gcc/gcc/0002-CVE-2021-42574.patch
> @@ -0,0 +1,2270 @@
> +From bd5e882cf6e0def3dd1bc106075d59a303fe0d1e Mon Sep 17 00:00:00
> 2001
> +From: David Malcolm <dmalcolm@redhat.com>
> +Date: Mon, 18 Oct 2021 18:55:31 -0400
> +Subject: [PATCH] diagnostics: escape non-ASCII source bytes for
> certain
> + diagnostics
> +MIME-Version: 1.0
> +Content-Type: text/plain; charset=utf8
> +Content-Transfer-Encoding: 8bit
> +
> +This patch adds support to GCC's diagnostic subsystem for escaping
> certain
> +bytes and Unicode characters when quoting source code.
> +
> +Specifically, this patch adds a new flag
> rich_location::m_escape_on_output
> +which is a hint from a diagnostic that non-ASCII bytes in the
> pertinent
> +lines of the user's source code should be escaped when printed.
> +
> +The patch sets this for the following diagnostics:
> +- when complaining about stray bytes in the program (when these
> +are non-printable)
> +- when complaining about "null character(s) ignored");
> +- for -Wnormalized= (and generate source ranges for such warnings)
> +
> +The escaping is controlled by a new option:
> +  -fdiagnostics-escape-format=[unicode|bytes]
> +
> +For example, consider a diagnostic involing a source line containing
> the
> +string "before" followed by the Unicode character U+03C0 ("GREEK
> SMALL
> +LETTER PI", with UTF-8 encoding 0xCF 0x80) followed by the byte 0xBF
> +(a stray UTF-8 trailing byte), followed by the string "after", where
> the
> +diagnostic highlights the U+03C0 character.
> +
> +By default, this line will be printed verbatim to the user when
> +reporting a diagnostic at it, as:
> +
> + beforeÏXafter
> +       ^
> +
> +(using X for the stray byte to avoid putting invalid UTF-8 in this
> +commit message)
> +
> +If the diagnostic sets the "escape" flag, it will be printed as:
> +
> + before<U+03C0><BF>after
> +       ^~~~~~~~
> +
> +with -fdiagnostics-escape-format=unicode (the default), or as:
> +
> +  before<CF><80><BF>after
> +        ^~~~~~~~
> +
> +if the user supplies -fdiagnostics-escape-format=bytes.
> +
> +This only affects how the source is printed; it does not affect
> +how column numbers that are printed (as per -fdiagnostics-column-
> unit=
> +and -fdiagnostics-column-origin=).
> +
> +gcc/c-family/ChangeLog:
> +       * c-lex.c (c_lex_with_flags): When complaining about non-
> printable
> +       CPP_OTHER tokens, set the "escape on output" flag.
> +
> +gcc/ChangeLog:
> +       * common.opt (fdiagnostics-escape-format=): New.
> +       (diagnostics_escape_format): New enum.
> +       (DIAGNOSTICS_ESCAPE_FORMAT_UNICODE): New enum value.
> +       (DIAGNOSTICS_ESCAPE_FORMAT_BYTES): Likewise.
> +       * diagnostic-format-json.cc (json_end_diagnostic): Add
> +       "escape-source" attribute.
> +       * diagnostic-show-locus.c
> +       (exploc_with_display_col::exploc_with_display_col): Replace
> +       "tabstop" param with a cpp_char_column_policy and add an
> "aspect"
> +       param.  Use these to compute m_display_col accordingly.
> +       (struct char_display_policy): New struct.
> +       (layout::m_policy): New field.
> +       (layout::m_escape_on_output): New field.
> +       (def_policy): New function.
> +       (make_range): Update for changes to exploc_with_display_col
> ctor.
> +       (default_print_decoded_ch): New.
> +       (width_per_escaped_byte): New.
> +       (escape_as_bytes_width): New.
> +       (escape_as_bytes_print): New.
> +       (escape_as_unicode_width): New.
> +       (escape_as_unicode_print): New.
> +       (make_policy): New.
> +       (layout::layout): Initialize new fields.  Update m_exploc
> ctor
> +       call for above change to ctor.
> +       (layout::maybe_add_location_range): Update for changes to
> +       exploc_with_display_col ctor.
> +       (layout::calculate_x_offset_display): Update for change to
> +       cpp_display_width.
> +       (layout::print_source_line): Pass policy
> +       to cpp_display_width_computation. Capture cpp_decoded_char
> when
> +       calling process_next_codepoint.  Move printing of source code
> to
> +       m_policy.m_print_cb.
> +       (line_label::line_label): Pass in policy rather than context.
> +       (layout::print_any_labels): Update for change to line_label
> ctor.
> +       (get_affected_range): Pass in policy rather than context,
> updating
> +       calls to location_compute_display_column accordingly.
> +       (get_printed_columns): Likewise, also for cpp_display_width.
> +       (correction::correction): Pass in policy rather than tabstop.
> +       (correction::compute_display_cols): Pass m_policy rather than
> +       m_tabstop to cpp_display_width.
> +       (correction::m_tabstop): Replace with...
> +       (correction::m_policy): ...this.
> +       (line_corrections::line_corrections): Pass in policy rather
> than
> +       context.
> +       (line_corrections::m_context): Replace with...
> +       (line_corrections::m_policy): ...this.
> +       (line_corrections::add_hint): Update to use m_policy rather
> than
> +       m_context.
> +       (line_corrections::add_hint): Likewise.
> +       (layout::print_trailing_fixits): Likewise.
> +       (selftest::test_display_widths): New.
> +       (selftest::test_layout_x_offset_display_utf8): Update to use
> +       policy rather than tabstop.
> +       (selftest::test_one_liner_labels_utf8): Add test of escaping
> +       source lines.
> +       (selftest::test_diagnostic_show_locus_one_liner_utf8): Update
> to
> +       use policy rather than tabstop.
> +       (selftest::test_overlapped_fixit_printing): Likewise.
> +       (selftest::test_overlapped_fixit_printing_utf8): Likewise.
> +       (selftest::test_overlapped_fixit_printing_2): Likewise.
> +       (selftest::test_tab_expansion): Likewise.
> +       (selftest::test_escaping_bytes_1): New.
> +       (selftest::test_escaping_bytes_2): New.
> +       (selftest::diagnostic_show_locus_c_tests): Call the new
> tests.
> +       * diagnostic.c (diagnostic_initialize): Initialize
> +       context->escape_format.
> +       (convert_column_unit): Update to use default character width
> policy.
> +       (selftest::test_diagnostic_get_location_text): Likewise.
> +       * diagnostic.h (enum diagnostics_escape_format): New enum.
> +       (diagnostic_context::escape_format): New field.
> +       * doc/invoke.texi (-fdiagnostics-escape-format=): New option.
> +       (-fdiagnostics-format=): Add "escape-source" attribute to
> examples
> +       of JSON output, and document it.
> +       * input.c (location_compute_display_column): Pass in "policy"
> +       rather than "tabstop", passing to
> +       cpp_byte_column_to_display_column.
> +       (selftest::test_cpp_utf8): Update to use
> cpp_char_column_policy.
> +       * input.h (class cpp_char_column_policy): New forward decl.
> +       (location_compute_display_column): Pass in "policy" rather
> than
> +       "tabstop".
> +       * opts.c (common_handle_option): Handle
> +       OPT_fdiagnostics_escape_format_.
> +       * selftest.c (temp_source_file::temp_source_file): New ctor
> +       overload taking a size_t.
> +       * selftest.h (temp_source_file::temp_source_file): Likewise.
> +
> +gcc/testsuite/ChangeLog:
> +       * c-c++-common/diagnostic-format-json-1.c: Add regexp to
> consume
> +       "escape-source" attribute.
> +       * c-c++-common/diagnostic-format-json-2.c: Likewise.
> +       * c-c++-common/diagnostic-format-json-3.c: Likewise.
> +       * c-c++-common/diagnostic-format-json-4.c: Likewise, twice.
> +       * c-c++-common/diagnostic-format-json-5.c: Likewise.
> +       * gcc.dg/cpp/warn-normalized-4-bytes.c: New test.
> +       * gcc.dg/cpp/warn-normalized-4-unicode.c: New test.
> +       * gcc.dg/encoding-issues-bytes.c: New test.
> +       * gcc.dg/encoding-issues-unicode.c: New test.
> +       * gfortran.dg/diagnostic-format-json-1.F90: Add regexp to
> consume
> +       "escape-source" attribute.
> +       * gfortran.dg/diagnostic-format-json-2.F90: Likewise.
> +       * gfortran.dg/diagnostic-format-json-3.F90: Likewise.
> +
> +libcpp/ChangeLog:
> +       * charset.c (convert_escape): Use encoding_rich_location when
> +       complaining about nonprintable unknown escape sequences.
> +       (cpp_display_width_computation::::cpp_display_width_computati
> on):
> +       Pass in policy rather than tabstop.
> +       (cpp_display_width_computation::process_next_codepoint): Add
> "out"
> +       param and populate *out if non-NULL.
> +       (cpp_display_width_computation::advance_display_cols): Pass
> NULL
> +       to process_next_codepoint.
> +       (cpp_byte_column_to_display_column): Pass in policy rather
> than
> +       tabstop.  Pass NULL to process_next_codepoint.
> +       (cpp_display_column_to_byte_column): Pass in policy rather
> than
> +       tabstop.
> +       * errors.c (cpp_diagnostic_get_current_location): New
> function,
> +       splitting out the logic from...
> +       (cpp_diagnostic): ...here.
> +       (cpp_warning_at): New function.
> +       (cpp_pedwarning_at): New function.
> +       * include/cpplib.h (cpp_warning_at): New decl for
> rich_location.
> +       (cpp_pedwarning_at): Likewise.
> +       (struct cpp_decoded_char): New.
> +       (struct cpp_char_column_policy): New.
> +       (cpp_display_width_computation::cpp_display_width_computation
> ):
> +       Replace "tabstop" param with "policy".
> +       (cpp_display_width_computation::process_next_codepoint): Add
> "out"
> +       param.
> +       (cpp_display_width_computation::m_tabstop): Replace with...
> +       (cpp_display_width_computation::m_policy): ...this.
> +       (cpp_byte_column_to_display_column): Replace "tabstop" param
> with
> +       "policy".
> +       (cpp_display_width): Likewise.
> +       (cpp_display_column_to_byte_column): Likewise.
> +       * include/line-map.h (rich_location::escape_on_output_p):
> New.
> +       (rich_location::set_escape_on_output): New.
> +       (rich_location::m_escape_on_output): New.
> +       * internal.h (cpp_diagnostic_get_current_location): New decl.
> +       (class encoding_rich_location): New.
> +       * lex.c (skip_whitespace): Use encoding_rich_location when
> +       complaining about null characters.
> +       (warn_about_normalization): Generate a source range when
> +       complaining about improperly normalized tokens, rather than
> just a
> +       point, and use encoding_rich_location so that the source code
> +       is escaped on printing.
> +       * line-map.c (rich_location::rich_location): Initialize
> +       m_escape_on_output.
> +
> +Signed-off-by: David Malcolm <dmalcolm@redhat.com>
> +
> +CVE: CVE-2021-42574
> +Upstream-Status: Backport
> [https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=bd5e882cf6e0def3dd1bc
> 106075d59a303fe0d1e]
> +Signed-off-by: Pgowda <pgowda.cve@gmail.com>
> +
> +---
> + gcc/c-family/c-lex.c                          |   6 +-
> + gcc/common.opt                                |  13 +
> + gcc/diagnostic-format-json.cc                 |   3 +
> + gcc/diagnostic-show-locus.c                   | 580
> +++++++++++++++---
> + gcc/diagnostic.c                              |  10 +-
> + gcc/diagnostic.h                              |  18 +
> + gcc/doc/invoke.texi                           |  43 +-
> + gcc/input.c                                   |  62 +-
> + gcc/input.h                                   |   7 +-
> + gcc/opts.c                                    |   4 +
> + gcc/selftest.c                                |  15 +
> + gcc/selftest.h                                |   2 +
> + .../c-c++-common/diagnostic-format-json-1.c   |   1 +
> + .../c-c++-common/diagnostic-format-json-2.c   |   1 +
> + .../c-c++-common/diagnostic-format-json-3.c   |   1 +
> + .../c-c++-common/diagnostic-format-json-4.c   |   2 +
> + .../c-c++-common/diagnostic-format-json-5.c   |   1 +
> + .../gcc.dg/cpp/warn-normalized-4-bytes.c      |  21 +
> + .../gcc.dg/cpp/warn-normalized-4-unicode.c    |  19 +
> + gcc/testsuite/gcc.dg/encoding-issues-bytes.c  | Bin 0 -> 595 bytes
> + .../gcc.dg/encoding-issues-unicode.c          | Bin 0 -> 613 bytes
> + .../gfortran.dg/diagnostic-format-json-1.F90  |   1 +
> + .../gfortran.dg/diagnostic-format-json-2.F90  |   1 +
> + .../gfortran.dg/diagnostic-format-json-3.F90  |   1 +
> + libcpp/charset.c                              |  63 +-
> + libcpp/errors.c                               |  82 ++-
> + libcpp/include/cpplib.h                       |  76 ++-
> + libcpp/include/line-map.h                     |  13 +
> + libcpp/internal.h                             |  23 +
> + libcpp/lex.c                                  |  38 +-
> + libcpp/line-map.c                             |   3 +-
> + 31 files changed, 942 insertions(+), 168 deletions(-)
> + create mode 100644 gcc/testsuite/gcc.dg/cpp/warn-normalized-4-
> bytes.c
> + create mode 100644 gcc/testsuite/gcc.dg/cpp/warn-normalized-4-
> unicode.c
> + create mode 100644 gcc/testsuite/gcc.dg/encoding-issues-bytes.c
> + create mode 100644 gcc/testsuite/gcc.dg/encoding-issues-unicode.c
> +
> +diff --git a/gcc/c-family/c-lex.c b/gcc/c-family/c-lex.c
> +--- a/gcc/c-family/c-lex.c     2020-07-22 23:35:17.296384022 -0700
> ++++ b/gcc/c-family/c-lex.c     2021-12-25 01:30:50.669689023 -0800
> +@@ -587,7 +587,11 @@ c_lex_with_flags (tree *value, location_
> +       else if (ISGRAPH (c))
> +         error_at (*loc, "stray %qc in program", (int) c);
> +       else
> +-        error_at (*loc, "stray %<\\%o%> in program", (int) c);
> ++        {
> ++          rich_location rich_loc (line_table, *loc);
> ++          rich_loc.set_escape_on_output (true);
> ++          error_at (&rich_loc, "stray %<\\%o%> in program", (int)
> c);
> ++        }
> +       }
> +       goto retry;
> +
> +diff --git a/gcc/common.opt b/gcc/common.opt
> +--- a/gcc/common.opt   2021-12-25 01:29:12.915317374 -0800
> ++++ b/gcc/common.opt   2021-12-25 01:30:50.669689023 -0800
> +@@ -1337,6 +1337,10 @@ fdiagnostics-format=
> + Common Joined RejectNegative Enum(diagnostics_output_format)
> + -fdiagnostics-format=[text|json]      Select output format.
> +
> ++fdiagnostics-escape-format=
> ++Common Joined RejectNegative Enum(diagnostics_escape_format)
> ++-fdiagnostics-escape-format=[unicode|bytes]   Select how to escape
> non-printable-ASCII bytes in the source for diagnostics that suggest
> it.
> ++
> + ; Required for these enum values.
> + SourceInclude
> + diagnostic.h
> +@@ -1351,6 +1355,15 @@ EnumValue
> + Enum(diagnostics_column_unit) String(byte)
> Value(DIAGNOSTICS_COLUMN_UNIT_BYTE)
> +
> + Enum
> ++Name(diagnostics_escape_format) Type(int)
> ++
> ++EnumValue
> ++Enum(diagnostics_escape_format) String(unicode)
> Value(DIAGNOSTICS_ESCAPE_FORMAT_UNICODE)
> ++
> ++EnumValue
> ++Enum(diagnostics_escape_format) String(bytes)
> Value(DIAGNOSTICS_ESCAPE_FORMAT_BYTES)
> ++
> ++Enum
> + Name(diagnostics_output_format) Type(int)
> +
> + EnumValue
> +diff --git a/gcc/diagnostic.c b/gcc/diagnostic.c
> +--- a/gcc/diagnostic.c 2021-12-25 01:29:12.915317374 -0800
> ++++ b/gcc/diagnostic.c 2021-12-25 01:30:50.669689023 -0800
> +@@ -223,6 +223,7 @@ diagnostic_initialize (diagnostic_contex
> +   context->column_unit = DIAGNOSTICS_COLUMN_UNIT_DISPLAY;
> +   context->column_origin = 1;
> +   context->tabstop = 8;
> ++  context->escape_format = DIAGNOSTICS_ESCAPE_FORMAT_UNICODE;
> +   context->edit_context_ptr = NULL;
> +   context->diagnostic_group_nesting_depth = 0;
> +   context->diagnostic_group_emission_count = 0;
> +@@ -2152,8 +2153,8 @@ test_diagnostic_get_location_text ()
> +     const char *const content = "smile \xf0\x9f\x98\x82\n";
> +     const int line_bytes = strlen (content) - 1;
> +     const int def_tabstop = 8;
> +-    const int display_width = cpp_display_width (content,
> line_bytes,
> +-                                               def_tabstop);
> ++    const cpp_char_column_policy policy (def_tabstop, cpp_wcwidth);
> ++    const int display_width = cpp_display_width (content,
> line_bytes, policy);
> +     ASSERT_EQ (line_bytes - 2, display_width);
> +     temp_source_file tmp (SELFTEST_LOCATION, ".c", content);
> +     const char *const fname = tmp.get_filename ();
> +diff --git a/gcc/diagnostic-format-json.cc b/gcc/diagnostic-format-
> json.cc
> +--- a/gcc/diagnostic-format-json.cc    2021-12-25 01:29:12.915317374
> -0800
> ++++ b/gcc/diagnostic-format-json.cc    2021-12-25 01:30:50.669689023
> -0800
> +@@ -264,6 +264,9 @@ json_end_diagnostic (diagnostic_context
> +       json::value *path_value = context->make_json_for_path
> (context, path);
> +       diag_obj->set ("path", path_value);
> +     }
> ++
> ++  diag_obj->set ("escape-source",
> ++               new json::literal (richloc->escape_on_output_p ()));
> + }
> +
> + /* No-op implementation of "begin_group_cb" for JSON output.  */
> +diff --git a/gcc/diagnostic.h b/gcc/diagnostic.h
> +--- a/gcc/diagnostic.h 2021-12-25 01:29:12.919317307 -0800
> ++++ b/gcc/diagnostic.h 2021-12-25 01:30:50.669689023 -0800
> +@@ -38,6 +38,20 @@ enum diagnostics_column_unit
> +   DIAGNOSTICS_COLUMN_UNIT_BYTE
> + };
> +
> ++/* An enum for controlling how to print non-ASCII characters/bytes
> when
> ++   a diagnostic suggests escaping the source code on output.  */
> ++
> ++enum diagnostics_escape_format
> ++{
> ++  /* Escape non-ASCII Unicode characters in the form <U+XXXX> and
> ++     non-UTF-8 bytes in the form <XX>.  */
> ++  DIAGNOSTICS_ESCAPE_FORMAT_UNICODE,
> ++
> ++  /* Escape non-ASCII bytes in the form <XX> (thus showing the
> underlying
> ++     encoding of non-ASCII Unicode characters).  */
> ++  DIAGNOSTICS_ESCAPE_FORMAT_BYTES
> ++};
> ++
> + /* Enum for overriding the standard output format.  */
> +
> + enum diagnostics_output_format
> +@@ -303,6 +317,10 @@ struct diagnostic_context
> +   /* The size of the tabstop for tab expansion.  */
> +   int tabstop;
> +
> ++  /* How should non-ASCII/non-printable bytes be escaped when
> ++     a diagnostic suggests escaping the source code on output.  */
> ++  enum diagnostics_escape_format escape_format;
> ++
> +   /* If non-NULL, an edit_context to which fix-it hints should be
> +      applied, for generating patches.  */
> +   edit_context *edit_context_ptr;
> +diff --git a/gcc/diagnostic-show-locus.c b/gcc/diagnostic-show-
> locus.c
> +--- a/gcc/diagnostic-show-locus.c      2021-12-25 01:29:12.919317307
> -0800
> ++++ b/gcc/diagnostic-show-locus.c      2021-12-25 01:30:50.673688956
> -0800
> +@@ -175,10 +175,26 @@ enum column_unit {
> + class exploc_with_display_col : public expanded_location
> + {
> +  public:
> +-  exploc_with_display_col (const expanded_location &exploc, int
> tabstop)
> +-    : expanded_location (exploc),
> +-      m_display_col (location_compute_display_column (exploc,
> tabstop))
> +-  {}
> ++  exploc_with_display_col (const expanded_location &exploc,
> ++                         const cpp_char_column_policy &policy,
> ++                         enum location_aspect aspect)
> ++  : expanded_location (exploc),
> ++    m_display_col (location_compute_display_column (exploc,
> policy))
> ++  {
> ++    if (exploc.column > 0)
> ++      {
> ++      /* m_display_col is now the final column of the byte.
> ++         If escaping has happened, we may want the first column
> instead.  */
> ++      if (aspect != LOCATION_ASPECT_FINISH)
> ++        {
> ++          expanded_location prev_exploc (exploc);
> ++          prev_exploc.column--;
> ++          int prev_display_col
> ++            = (location_compute_display_column (prev_exploc,
> policy));
> ++          m_display_col = prev_display_col + 1;
> ++        }
> ++      }
> ++  }
> +
> +   int m_display_col;
> + };
> +@@ -313,6 +329,31 @@ test_line_span ()
> +
> + #endif /* #if CHECKING_P */
> +
> ++/* A bundle of information containing how to print unicode
> ++   characters and bytes when quoting source code.
> ++
> ++   Provides a unified place to support escaping some subset
> ++   of characters to some format.
> ++
> ++   Extends char_column_policy; printing is split out to avoid
> ++   libcpp having to know about pretty_printer.  */
> ++
> ++struct char_display_policy : public cpp_char_column_policy
> ++{
> ++ public:
> ++  char_display_policy (int tabstop,
> ++                     int (*width_cb) (cppchar_t c),
> ++                     void (*print_cb) (pretty_printer *pp,
> ++                                       const cpp_decoded_char &cp))
> ++  : cpp_char_column_policy (tabstop, width_cb),
> ++    m_print_cb (print_cb)
> ++  {
> ++  }
> ++
> ++  void (*m_print_cb) (pretty_printer *pp,
> ++                    const cpp_decoded_char &cp);
> ++};
> ++
> + /* A class to control the overall layout when printing a
> diagnostic.
> +
> +    The layout is determined within the constructor.
> +@@ -345,6 +386,8 @@ class layout
> +
> +   void print_line (linenum_type row);
> +
> ++  void on_bad_codepoint (const char *ptr, cppchar_t ch, size_t
> ch_sz);
> ++
> +  private:
> +   bool will_show_line_p (linenum_type row) const;
> +   void print_leading_fixits (linenum_type row);
> +@@ -386,6 +429,7 @@ class layout
> +  private:
> +   diagnostic_context *m_context;
> +   pretty_printer *m_pp;
> ++  char_display_policy m_policy;
> +   location_t m_primary_loc;
> +   exploc_with_display_col m_exploc;
> +   colorizer m_colorizer;
> +@@ -398,6 +442,7 @@ class layout
> +   auto_vec <line_span> m_line_spans;
> +   int m_linenum_width;
> +   int m_x_offset_display;
> ++  bool m_escape_on_output;
> + };
> +
> + /* Implementation of "class colorizer".  */
> +@@ -646,6 +691,11 @@ layout_range::intersects_line_p (linenum
> + /* Default for when we don't care what the tab expansion is set
> to.  */
> + static const int def_tabstop = 8;
> +
> ++static cpp_char_column_policy def_policy ()
> ++{
> ++  return cpp_char_column_policy (8, cpp_wcwidth);
> ++}
> ++
> + /* Create some expanded locations for testing layout_range.  The
> filename
> +    member of the explocs is set to the empty string.  This member
> will only be
> +    inspected by the calls to location_compute_display_column() made
> from the
> +@@ -662,10 +712,13 @@ make_range (int start_line, int start_co
> +     = {"", start_line, start_col, NULL, false};
> +   const expanded_location finish_exploc
> +     = {"", end_line, end_col, NULL, false};
> +-  return layout_range (exploc_with_display_col (start_exploc,
> def_tabstop),
> +-                     exploc_with_display_col (finish_exploc,
> def_tabstop),
> ++  return layout_range (exploc_with_display_col (start_exploc,
> def_policy (),
> ++                                              LOCATION_ASPECT_START
> ),
> ++                     exploc_with_display_col (finish_exploc,
> def_policy (),
> ++                                              LOCATION_ASPECT_FINIS
> H),
> +                      SHOW_RANGE_WITHOUT_CARET,
> +-                     exploc_with_display_col (start_exploc,
> def_tabstop),
> ++                     exploc_with_display_col (start_exploc,
> def_policy (),
> ++                                              LOCATION_ASPECT_CARET
> ),
> +                      0, NULL);
> + }
> +
> +@@ -950,6 +1003,164 @@ fixit_cmp (const void *p_a, const void *
> +   return hint_a->get_start_loc () - hint_b->get_start_loc ();
> + }
> +
> ++/* Callbacks for use when not escaping the source.  */
> ++
> ++/* The default callback for char_column_policy::m_width_cb is
> cpp_wcwidth.  */
> ++
> ++/* Callback for char_display_policy::m_print_cb for printing source
> chars
> ++   when not escaping the source.  */
> ++
> ++static void
> ++default_print_decoded_ch (pretty_printer *pp,
> ++                        const cpp_decoded_char &decoded_ch)
> ++{
> ++  for (const char *ptr = decoded_ch.m_start_byte;
> ++       ptr != decoded_ch.m_next_byte; ptr++)
> ++    {
> ++      if (*ptr == '\0' || *ptr == '\r')
> ++      {
> ++        pp_space (pp);
> ++        continue;
> ++      }
> ++
> ++      pp_character (pp, *ptr);
> ++    }
> ++}
> ++
> ++/* Callbacks for use with DIAGNOSTICS_ESCAPE_FORMAT_BYTES.  */
> ++
> ++static const int width_per_escaped_byte = 4;
> ++
> ++/* Callback for char_column_policy::m_width_cb for determining the
> ++   display width when escaping with
> DIAGNOSTICS_ESCAPE_FORMAT_BYTES.  */
> ++
> ++static int
> ++escape_as_bytes_width (cppchar_t ch)
> ++{
> ++  if (ch < 0x80 && ISPRINT (ch))
> ++    return cpp_wcwidth (ch);
> ++  else
> ++    {
> ++      if (ch <=   0x7F) return 1 * width_per_escaped_byte;
> ++      if (ch <=  0x7FF) return 2 * width_per_escaped_byte;
> ++      if (ch <= 0xFFFF) return 3 * width_per_escaped_byte;
> ++      return 4 * width_per_escaped_byte;
> ++    }
> ++}
> ++
> ++/* Callback for char_display_policy::m_print_cb for printing source
> chars
> ++   when escaping with DIAGNOSTICS_ESCAPE_FORMAT_BYTES.  */
> ++
> ++static void
> ++escape_as_bytes_print (pretty_printer *pp,
> ++                     const cpp_decoded_char &decoded_ch)
> ++{
> ++  if (!decoded_ch.m_valid_ch)
> ++    {
> ++      for (const char *iter = decoded_ch.m_start_byte;
> ++         iter != decoded_ch.m_next_byte; ++iter)
> ++      {
> ++        char buf[16];
> ++        sprintf (buf, "<%02x>", (unsigned char)*iter);
> ++        pp_string (pp, buf);
> ++      }
> ++      return;
> ++    }
> ++
> ++  cppchar_t ch = decoded_ch.m_ch;
> ++  if (ch < 0x80 && ISPRINT (ch))
> ++    pp_character (pp, ch);
> ++  else
> ++    {
> ++      for (const char *iter = decoded_ch.m_start_byte;
> ++         iter < decoded_ch.m_next_byte; ++iter)
> ++      {
> ++        char buf[16];
> ++        sprintf (buf, "<%02x>", (unsigned char)*iter);
> ++        pp_string (pp, buf);
> ++      }
> ++    }
> ++}
> ++
> ++/* Callbacks for use with DIAGNOSTICS_ESCAPE_FORMAT_UNICODE.  */
> ++
> ++/* Callback for char_column_policy::m_width_cb for determining the
> ++   display width when escaping with
> DIAGNOSTICS_ESCAPE_FORMAT_UNICODE.  */
> ++
> ++static int
> ++escape_as_unicode_width (cppchar_t ch)
> ++{
> ++  if (ch < 0x80 && ISPRINT (ch))
> ++    return cpp_wcwidth (ch);
> ++  else
> ++    {
> ++      // Width of "<U+%04x>"
> ++      if (ch > 0xfffff)
> ++      return 10;
> ++      else if (ch > 0xffff)
> ++      return 9;
> ++      else
> ++      return 8;
> ++    }
> ++}
> ++
> ++/* Callback for char_display_policy::m_print_cb for printing source
> chars
> ++   when escaping with DIAGNOSTICS_ESCAPE_FORMAT_UNICODE.  */
> ++
> ++static void
> ++escape_as_unicode_print (pretty_printer *pp,
> ++                       const cpp_decoded_char &decoded_ch)
> ++{
> ++  if (!decoded_ch.m_valid_ch)
> ++    {
> ++      escape_as_bytes_print (pp, decoded_ch);
> ++      return;
> ++    }
> ++
> ++  cppchar_t ch = decoded_ch.m_ch;
> ++  if (ch < 0x80 && ISPRINT (ch))
> ++    pp_character (pp, ch);
> ++  else
> ++    {
> ++      char buf[16];
> ++      sprintf (buf, "<U+%04X>", ch);
> ++      pp_string (pp, buf);
> ++    }
> ++}
> ++
> ++/* Populate a char_display_policy based on DC and RICHLOC.  */
> ++
> ++static char_display_policy
> ++make_policy (const diagnostic_context &dc,
> ++           const rich_location &richloc)
> ++{
> ++  /* The default is to not escape non-ASCII bytes.  */
> ++  char_display_policy result
> ++    (dc.tabstop, cpp_wcwidth, default_print_decoded_ch);
> ++
> ++  /* If the diagnostic suggests escaping non-ASCII bytes, then
> ++     use policy from user-supplied options.  */
> ++  if (richloc.escape_on_output_p ())
> ++    {
> ++      result.m_undecoded_byte_width = width_per_escaped_byte;
> ++      switch (dc.escape_format)
> ++      {
> ++      default:
> ++        gcc_unreachable ();
> ++      case DIAGNOSTICS_ESCAPE_FORMAT_UNICODE:
> ++        result.m_width_cb = escape_as_unicode_width;
> ++        result.m_print_cb = escape_as_unicode_print;
> ++        break;
> ++      case DIAGNOSTICS_ESCAPE_FORMAT_BYTES:
> ++        result.m_width_cb = escape_as_bytes_width;
> ++        result.m_print_cb = escape_as_bytes_print;
> ++        break;
> ++      }
> ++    }
> ++
> ++  return result;
> ++}
> ++
> + /* Implementation of class layout.  */
> +
> + /* Constructor for class layout.
> +@@ -966,8 +1177,10 @@ layout::layout (diagnostic_context * con
> +               diagnostic_t diagnostic_kind)
> + : m_context (context),
> +   m_pp (context->printer),
> ++  m_policy (make_policy (*context, *richloc)),
> +   m_primary_loc (richloc->get_range (0)->m_loc),
> +-  m_exploc (richloc->get_expanded_location (0), context->tabstop),
> ++  m_exploc (richloc->get_expanded_location (0), m_policy,
> ++          LOCATION_ASPECT_CARET),
> +   m_colorizer (context, diagnostic_kind),
> +   m_colorize_source_p (context->colorize_source_p),
> +   m_show_labels_p (context->show_labels_p),
> +@@ -977,7 +1190,8 @@ layout::layout (diagnostic_context * con
> +   m_fixit_hints (richloc->get_num_fixit_hints ()),
> +   m_line_spans (1 + richloc->get_num_locations ()),
> +   m_linenum_width (0),
> +-  m_x_offset_display (0)
> ++  m_x_offset_display (0),
> ++  m_escape_on_output (richloc->escape_on_output_p ())
> + {
> +   for (unsigned int idx = 0; idx < richloc->get_num_locations ();
> idx++)
> +     {
> +@@ -1063,10 +1277,13 @@ layout::maybe_add_location_range (const
> +
> +   /* Everything is now known to be in the correct source file,
> +      but it may require further sanitization.  */
> +-  layout_range ri (exploc_with_display_col (start, m_context-
> >tabstop),
> +-                 exploc_with_display_col (finish, m_context-
> >tabstop),
> ++  layout_range ri (exploc_with_display_col (start, m_policy,
> ++                                          LOCATION_ASPECT_START),
> ++                 exploc_with_display_col (finish, m_policy,
> ++                                          LOCATION_ASPECT_FINISH),
> +                  loc_range->m_range_display_kind,
> +-                 exploc_with_display_col (caret, m_context-
> >tabstop),
> ++                 exploc_with_display_col (caret, m_policy,
> ++                                          LOCATION_ASPECT_CARET),
> +                  original_idx, loc_range->m_label);
> +
> +   /* If we have a range that finishes before it starts (perhaps
> +@@ -1400,7 +1617,7 @@ layout::calculate_x_offset_display ()
> +     = get_line_bytes_without_trailing_whitespace (line.get_buffer
> (),
> +                                                 line.length ());
> +   int eol_display_column
> +-    = cpp_display_width (line.get_buffer (), line_bytes, m_context-
> >tabstop);
> ++    = cpp_display_width (line.get_buffer (), line_bytes, m_policy);
> +   if (caret_display_column > eol_display_column
> +       || !caret_display_column)
> +     {
> +@@ -1479,7 +1696,7 @@ layout::print_source_line (linenum_type
> +   /* This object helps to keep track of which display column we are
> at, which is
> +      necessary for computing the line bounds in display units, for
> doing
> +      tab expansion, and for implementing m_x_offset_display.  */
> +-  cpp_display_width_computation dw (line, line_bytes, m_context-
> >tabstop);
> ++  cpp_display_width_computation dw (line, line_bytes, m_policy);
> +
> +   /* Skip the first m_x_offset_display display columns.  In case
> the leading
> +      portion that will be skipped ends with a character with
> wcwidth > 1, then
> +@@ -1527,7 +1744,8 @@ layout::print_source_line (linenum_type
> +        tabs and replacing some control bytes with spaces as
> necessary.  */
> +       const char *c = dw.next_byte ();
> +       const int start_disp_col = dw.display_cols_processed () + 1;
> +-      const int this_display_width = dw.process_next_codepoint ();
> ++      cpp_decoded_char cp;
> ++      const int this_display_width = dw.process_next_codepoint
> (&cp);
> +       if (*c == '\t')
> +       {
> +         /* The returned display width is the number of spaces into
> which the
> +@@ -1536,15 +1754,6 @@ layout::print_source_line (linenum_type
> +           pp_space (m_pp);
> +         continue;
> +       }
> +-      if (*c == '\0' || *c == '\r')
> +-      {
> +-        /* cpp_wcwidth() promises to return 1 for all control
> bytes, and we
> +-           want to output these as a single space too, so this case
> is
> +-           actually the same as the '\t' case.  */
> +-        gcc_assert (this_display_width == 1);
> +-        pp_space (m_pp);
> +-        continue;
> +-      }
> +
> +       /* We have a (possibly multibyte) character to output; update
> the line
> +        bounds if it is not whitespace.  */
> +@@ -1556,7 +1765,8 @@ layout::print_source_line (linenum_type
> +       }
> +
> +       /* Output the character.  */
> +-      while (c != dw.next_byte ()) pp_character (m_pp, *c++);
> ++      m_policy.m_print_cb (m_pp, cp);
> ++      c = dw.next_byte ();
> +     }
> +   print_newline ();
> +   return lbounds;
> +@@ -1655,14 +1865,14 @@ layout::print_annotation_line (linenum_t
> + class line_label
> + {
> + public:
> +-  line_label (diagnostic_context *context, int state_idx, int
> column,
> ++  line_label (const cpp_char_column_policy &policy,
> ++            int state_idx, int column,
> +             label_text text)
> +   : m_state_idx (state_idx), m_column (column),
> +     m_text (text), m_label_line (0), m_has_vbar (true)
> +   {
> +     const int bytes = strlen (text.m_buffer);
> +-    m_display_width
> +-      = cpp_display_width (text.m_buffer, bytes, context->tabstop);
> ++    m_display_width = cpp_display_width (text.m_buffer, bytes,
> policy);
> +   }
> +
> +   /* Sorting is primarily by column, then by state index.  */
> +@@ -1722,7 +1932,7 @@ layout::print_any_labels (linenum_type r
> +       if (text.m_buffer == NULL)
> +         continue;
> +
> +-      labels.safe_push (line_label (m_context, i, disp_col, text));
> ++      labels.safe_push (line_label (m_policy, i, disp_col, text));
> +       }
> +   }
> +
> +@@ -2002,7 +2212,7 @@ public:
> +
> + /* Get the range of bytes or display columns that HINT would
> affect.  */
> + static column_range
> +-get_affected_range (diagnostic_context *context,
> ++get_affected_range (const cpp_char_column_policy &policy,
> +                   const fixit_hint *hint, enum column_unit
> col_unit)
> + {
> +   expanded_location exploc_start = expand_location (hint-
> >get_start_loc ());
> +@@ -2013,13 +2223,11 @@ get_affected_range (diagnostic_context *
> +   int finish_column;
> +   if (col_unit == CU_DISPLAY_COLS)
> +     {
> +-      start_column
> +-      = location_compute_display_column (exploc_start, context-
> >tabstop);
> ++      start_column = location_compute_display_column (exploc_start,
> policy);
> +       if (hint->insertion_p ())
> +       finish_column = start_column - 1;
> +       else
> +-      finish_column
> +-        = location_compute_display_column (exploc_finish, context-
> >tabstop);
> ++      finish_column = location_compute_display_column
> (exploc_finish, policy);
> +     }
> +   else
> +     {
> +@@ -2032,12 +2240,13 @@ get_affected_range (diagnostic_context *
> + /* Get the range of display columns that would be printed for
> HINT.  */
> +
> + static column_range
> +-get_printed_columns (diagnostic_context *context, const fixit_hint
> *hint)
> ++get_printed_columns (const cpp_char_column_policy &policy,
> ++                   const fixit_hint *hint)
> + {
> +   expanded_location exploc = expand_location (hint->get_start_loc
> ());
> +-  int start_column = location_compute_display_column (exploc,
> context->tabstop);
> ++  int start_column = location_compute_display_column (exploc,
> policy);
> +   int hint_width = cpp_display_width (hint->get_string (), hint-
> >get_length (),
> +-                                    context->tabstop);
> ++                                    policy);
> +   int final_hint_column = start_column + hint_width - 1;
> +   if (hint->insertion_p ())
> +     {
> +@@ -2047,8 +2256,7 @@ get_printed_columns (diagnostic_context
> +     {
> +       exploc = expand_location (hint->get_next_loc ());
> +       --exploc.column;
> +-      int finish_column
> +-      = location_compute_display_column (exploc, context->tabstop);
> ++      int finish_column = location_compute_display_column (exploc,
> policy);
> +       return column_range (start_column,
> +                          MAX (finish_column, final_hint_column));
> +     }
> +@@ -2066,13 +2274,13 @@ public:
> +             column_range affected_columns,
> +             column_range printed_columns,
> +             const char *new_text, size_t new_text_len,
> +-            int tabstop)
> ++            const cpp_char_column_policy &policy)
> +   : m_affected_bytes (affected_bytes),
> +     m_affected_columns (affected_columns),
> +     m_printed_columns (printed_columns),
> +     m_text (xstrdup (new_text)),
> +     m_byte_length (new_text_len),
> +-    m_tabstop (tabstop),
> ++    m_policy (policy),
> +     m_alloc_sz (new_text_len + 1)
> +   {
> +     compute_display_cols ();
> +@@ -2090,7 +2298,7 @@ public:
> +
> +   void compute_display_cols ()
> +   {
> +-    m_display_cols = cpp_display_width (m_text, m_byte_length,
> m_tabstop);
> ++    m_display_cols = cpp_display_width (m_text, m_byte_length,
> m_policy);
> +   }
> +
> +   void overwrite (int dst_offset, const char_span &src_span)
> +@@ -2118,7 +2326,7 @@ public:
> +   char *m_text;
> +   size_t m_byte_length; /* Not including null-terminator.  */
> +   int m_display_cols;
> +-  int m_tabstop;
> ++  const cpp_char_column_policy &m_policy;
> +   size_t m_alloc_sz;
> + };
> +
> +@@ -2154,15 +2362,16 @@ correction::ensure_terminated ()
> + class line_corrections
> + {
> + public:
> +-  line_corrections (diagnostic_context *context, const char
> *filename,
> ++  line_corrections (const char_display_policy &policy,
> ++                  const char *filename,
> +                   linenum_type row)
> +-    : m_context (context), m_filename (filename), m_row (row)
> ++  : m_policy (policy), m_filename (filename), m_row (row)
> +   {}
> +   ~line_corrections ();
> +
> +   void add_hint (const fixit_hint *hint);
> +
> +-  diagnostic_context *m_context;
> ++  const char_display_policy &m_policy;
> +   const char *m_filename;
> +   linenum_type m_row;
> +   auto_vec <correction *> m_corrections;
> +@@ -2208,10 +2417,10 @@ source_line::source_line (const char *fi
> + void
> + line_corrections::add_hint (const fixit_hint *hint)
> + {
> +-  column_range affected_bytes = get_affected_range (m_context,
> hint, CU_BYTES);
> +-  column_range affected_columns = get_affected_range (m_context,
> hint,
> ++  column_range affected_bytes = get_affected_range (m_policy, hint,
> CU_BYTES);
> ++  column_range affected_columns = get_affected_range (m_policy,
> hint,
> +
> CU_DISPLAY_COLS);
> +-  column_range printed_columns = get_printed_columns (m_context,
> hint);
> ++  column_range printed_columns = get_printed_columns (m_policy,
> hint);
> +
> +   /* Potentially consolidate.  */
> +   if (!m_corrections.is_empty ())
> +@@ -2280,7 +2489,7 @@ line_corrections::add_hint (const fixit_
> +                                          printed_columns,
> +                                          hint->get_string (),
> +                                          hint->get_length (),
> +-                                         m_context->tabstop));
> ++                                         m_policy));
> + }
> +
> + /* If there are any fixit hints on source line ROW, print them.
> +@@ -2294,7 +2503,7 @@ layout::print_trailing_fixits (linenum_t
> + {
> +   /* Build a list of correction instances for the line,
> +      potentially consolidating hints (for the sake of
> readability).  */
> +-  line_corrections corrections (m_context, m_exploc.file, row);
> ++  line_corrections corrections (m_policy, m_exploc.file, row);
> +   for (unsigned int i = 0; i < m_fixit_hints.length (); i++)
> +     {
> +       const fixit_hint *hint = m_fixit_hints[i];
> +@@ -2635,6 +2844,59 @@ namespace selftest {
> +
> + /* Selftests for diagnostic_show_locus.  */
> +
> ++/* Verify that cpp_display_width correctly handles escaping.  */
> ++
> ++static void
> ++test_display_widths ()
> ++{
> ++  gcc_rich_location richloc (UNKNOWN_LOCATION);
> ++
> ++  /* U+03C0 "GREEK SMALL LETTER PI".  */
> ++  const char *pi = "\xCF\x80";
> ++  /* U+1F642 "SLIGHTLY SMILING FACE".  */
> ++  const char *emoji = "\xF0\x9F\x99\x82";
> ++  /* Stray trailing byte of a UTF-8 character.  */
> ++  const char *stray = "\xBF";
> ++  /* U+10FFFF.  */
> ++  const char *max_codepoint = "\xF4\x8F\xBF\xBF";
> ++
> ++  /* No escaping.  */
> ++  {
> ++    test_diagnostic_context dc;
> ++    char_display_policy policy (make_policy (dc, richloc));
> ++    ASSERT_EQ (cpp_display_width (pi, strlen (pi), policy), 1);
> ++    ASSERT_EQ (cpp_display_width (emoji, strlen (emoji), policy),
> 2);
> ++    ASSERT_EQ (cpp_display_width (stray, strlen (stray), policy),
> 1);
> ++    /* Don't check width of U+10FFFF; it's in a private use plane.
> */
> ++  }
> ++
> ++  richloc.set_escape_on_output (true);
> ++
> ++  {
> ++    test_diagnostic_context dc;
> ++    dc.escape_format = DIAGNOSTICS_ESCAPE_FORMAT_UNICODE;
> ++    char_display_policy policy (make_policy (dc, richloc));
> ++    ASSERT_EQ (cpp_display_width (pi, strlen (pi), policy), 8);
> ++    ASSERT_EQ (cpp_display_width (emoji, strlen (emoji), policy),
> 9);
> ++    ASSERT_EQ (cpp_display_width (stray, strlen (stray), policy),
> 4);
> ++    ASSERT_EQ (cpp_display_width (max_codepoint, strlen
> (max_codepoint),
> ++                                policy),
> ++             strlen ("<U+10FFFF>"));
> ++  }
> ++
> ++  {
> ++    test_diagnostic_context dc;
> ++    dc.escape_format = DIAGNOSTICS_ESCAPE_FORMAT_BYTES;
> ++    char_display_policy policy (make_policy (dc, richloc));
> ++    ASSERT_EQ (cpp_display_width (pi, strlen (pi), policy), 8);
> ++    ASSERT_EQ (cpp_display_width (emoji, strlen (emoji), policy),
> 16);
> ++    ASSERT_EQ (cpp_display_width (stray, strlen (stray), policy),
> 4);
> ++    ASSERT_EQ (cpp_display_width (max_codepoint, strlen
> (max_codepoint),
> ++                                policy),
> ++             16);
> ++  }
> ++}
> ++
> + /* For precise tests of the layout, make clear where the source
> line will
> +    start.  test_left_margin sets the total byte count from the left
> side of the
> +    screen to the start of source lines, after the line number and
> the separator,
> +@@ -2704,10 +2966,10 @@ test_layout_x_offset_display_utf8 (const
> +   char_span lspan = location_get_source_line (tmp.get_filename (),
> 1);
> +   ASSERT_EQ (line_display_cols,
> +            cpp_display_width (lspan.get_buffer (), lspan.length (),
> +-                              def_tabstop));
> ++                              def_policy ()));
> +   ASSERT_EQ (line_display_cols,
> +            location_compute_display_column (expand_location
> (line_end),
> +-                                            def_tabstop));
> ++                                            def_policy ()));
> +   ASSERT_EQ (0, memcmp (lspan.get_buffer () + (emoji_col - 1),
> +                       "\xf0\x9f\x98\x82\xf0\x9f\x98\x82", 8));
> +
> +@@ -2855,12 +3117,13 @@ test_layout_x_offset_display_tab (const
> +   ASSERT_EQ ('\t', *(lspan.get_buffer () + (tab_col - 1)));
> +   for (int tabstop = 1; tabstop != num_tabstops; ++tabstop)
> +     {
> ++      cpp_char_column_policy policy (tabstop, cpp_wcwidth);
> +       ASSERT_EQ (line_bytes + extra_width[tabstop],
> +                cpp_display_width (lspan.get_buffer (), lspan.length
> (),
> +-                                  tabstop));
> ++                                  policy));
> +       ASSERT_EQ (line_bytes + extra_width[tabstop],
> +                location_compute_display_column (expand_location
> (line_end),
> +-                                                tabstop));
> ++                                                policy));
> +     }
> +
> +   /* Check that the tab is expanded to the expected number of
> spaces.  */
> +@@ -3992,6 +4255,43 @@ test_one_liner_labels_utf8 ()
> +                          " bb\xf0\x9f\x98\x82\xf0\x9f\x98\x82\n",
> +                 pp_formatted_text (dc.printer));
> +   }
> ++
> ++  /* Example of escaping the source lines.  */
> ++  {
> ++    text_range_label label0 ("label 0\xf0\x9f\x98\x82");
> ++    text_range_label label1 ("label 1\xcf\x80");
> ++    text_range_label label2 ("label 2\xcf\x80");
> ++    gcc_rich_location richloc (foo, &label0);
> ++    richloc.add_range (bar, SHOW_RANGE_WITHOUT_CARET, &label1);
> ++    richloc.add_range (field, SHOW_RANGE_WITHOUT_CARET, &label2);
> ++    richloc.set_escape_on_output (true);
> ++
> ++    {
> ++      test_diagnostic_context dc;
> ++      dc.escape_format = DIAGNOSTICS_ESCAPE_FORMAT_UNICODE;
> ++      diagnostic_show_locus (&dc, &richloc, DK_ERROR);
> ++      ASSERT_STREQ (" <U+1F602>_foo =
> <U+03C0>_bar.<U+1F602>_field<U+03C0>;\n"
> ++                  " ^~~~~~~~~~~~~   ~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~\n"
> ++                  " |               |            |\n"
> ++                  " |               |            label 2\xcf\x80\n"
> ++                  " |               label 1\xcf\x80\n"
> ++                  " label 0\xf0\x9f\x98\x82\n",
> ++                  pp_formatted_text (dc.printer));
> ++    }
> ++    {
> ++      test_diagnostic_context dc;
> ++      dc.escape_format = DIAGNOSTICS_ESCAPE_FORMAT_BYTES;
> ++      diagnostic_show_locus (&dc, &richloc, DK_ERROR);
> ++      ASSERT_STREQ
> ++      (" <f0><9f><98><82>_foo =
> <cf><80>_bar.<f0><9f><98><82>_field<cf><80>;\n"
> ++       " ^~~~~~~~~~~~~~~~~~~~   ~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n"
> ++       " |                      |            |\n"
> ++       " |                      |            label 2\xcf\x80\n"
> ++       " |                      label 1\xcf\x80\n"
> ++       " label 0\xf0\x9f\x98\x82\n",
> ++       pp_formatted_text (dc.printer));
> ++    }
> ++  }
> + }
> +
> + /* Make sure that colorization codes don't interrupt a multibyte
> +@@ -4046,9 +4346,9 @@ test_diagnostic_show_locus_one_liner_utf
> +
> +   char_span lspan = location_get_source_line (tmp.get_filename (),
> 1);
> +   ASSERT_EQ (25, cpp_display_width (lspan.get_buffer (),
> lspan.length (),
> +-                                  def_tabstop));
> ++                                  def_policy ()));
> +   ASSERT_EQ (25, location_compute_display_column (expand_location
> (line_end),
> +-                                                def_tabstop));
> ++                                                def_policy ()));
> +
> +   test_one_liner_simple_caret_utf8 ();
> +   test_one_liner_caret_and_range_utf8 ();
> +@@ -4434,30 +4734,31 @@ test_overlapped_fixit_printing (const li
> +                 pp_formatted_text (dc.printer));
> +
> +     /* Unit-test the line_corrections machinery.  */
> ++    char_display_policy policy (make_policy (dc, richloc));
> +     ASSERT_EQ (3, richloc.get_num_fixit_hints ());
> +     const fixit_hint *hint_0 = richloc.get_fixit_hint (0);
> +     ASSERT_EQ (column_range (12, 12),
> +-             get_affected_range (&dc, hint_0, CU_BYTES));
> ++             get_affected_range (policy, hint_0, CU_BYTES));
> +     ASSERT_EQ (column_range (12, 12),
> +-             get_affected_range (&dc, hint_0, CU_DISPLAY_COLS));
> +-    ASSERT_EQ (column_range (12, 22), get_printed_columns (&dc,
> hint_0));
> ++             get_affected_range (policy, hint_0, CU_DISPLAY_COLS));
> ++    ASSERT_EQ (column_range (12, 22), get_printed_columns (policy,
> hint_0));
> +     const fixit_hint *hint_1 = richloc.get_fixit_hint (1);
> +     ASSERT_EQ (column_range (18, 18),
> +-             get_affected_range (&dc, hint_1, CU_BYTES));
> ++             get_affected_range (policy, hint_1, CU_BYTES));
> +     ASSERT_EQ (column_range (18, 18),
> +-             get_affected_range (&dc, hint_1, CU_DISPLAY_COLS));
> +-    ASSERT_EQ (column_range (18, 20), get_printed_columns (&dc,
> hint_1));
> ++             get_affected_range (policy, hint_1, CU_DISPLAY_COLS));
> ++    ASSERT_EQ (column_range (18, 20), get_printed_columns (policy,
> hint_1));
> +     const fixit_hint *hint_2 = richloc.get_fixit_hint (2);
> +     ASSERT_EQ (column_range (29, 28),
> +-             get_affected_range (&dc, hint_2, CU_BYTES));
> ++             get_affected_range (policy, hint_2, CU_BYTES));
> +     ASSERT_EQ (column_range (29, 28),
> +-             get_affected_range (&dc, hint_2, CU_DISPLAY_COLS));
> +-    ASSERT_EQ (column_range (29, 29), get_printed_columns (&dc,
> hint_2));
> ++             get_affected_range (policy, hint_2, CU_DISPLAY_COLS));
> ++    ASSERT_EQ (column_range (29, 29), get_printed_columns (policy,
> hint_2));
> +
> +     /* Add each hint in turn to a line_corrections instance,
> +        and verify that they are consolidated into one correction
> instance
> +        as expected.  */
> +-    line_corrections lc (&dc, tmp.get_filename (), 1);
> ++    line_corrections lc (policy, tmp.get_filename (), 1);
> +
> +     /* The first replace hint by itself.  */
> +     lc.add_hint (hint_0);
> +@@ -4649,30 +4950,31 @@ test_overlapped_fixit_printing_utf8 (con
> +                 pp_formatted_text (dc.printer));
> +
> +     /* Unit-test the line_corrections machinery.  */
> ++    char_display_policy policy (make_policy (dc, richloc));
> +     ASSERT_EQ (3, richloc.get_num_fixit_hints ());
> +     const fixit_hint *hint_0 = richloc.get_fixit_hint (0);
> +     ASSERT_EQ (column_range (14, 14),
> +-             get_affected_range (&dc, hint_0, CU_BYTES));
> ++             get_affected_range (policy, hint_0, CU_BYTES));
> +     ASSERT_EQ (column_range (12, 12),
> +-             get_affected_range (&dc, hint_0, CU_DISPLAY_COLS));
> +-    ASSERT_EQ (column_range (12, 22), get_printed_columns (&dc,
> hint_0));
> ++             get_affected_range (policy, hint_0, CU_DISPLAY_COLS));
> ++    ASSERT_EQ (column_range (12, 22), get_printed_columns (policy,
> hint_0));
> +     const fixit_hint *hint_1 = richloc.get_fixit_hint (1);
> +     ASSERT_EQ (column_range (22, 22),
> +-             get_affected_range (&dc, hint_1, CU_BYTES));
> ++             get_affected_range (policy, hint_1, CU_BYTES));
> +     ASSERT_EQ (column_range (18, 18),
> +-             get_affected_range (&dc, hint_1, CU_DISPLAY_COLS));
> +-    ASSERT_EQ (column_range (18, 20), get_printed_columns (&dc,
> hint_1));
> ++             get_affected_range (policy, hint_1, CU_DISPLAY_COLS));
> ++    ASSERT_EQ (column_range (18, 20), get_printed_columns (policy,
> hint_1));
> +     const fixit_hint *hint_2 = richloc.get_fixit_hint (2);
> +     ASSERT_EQ (column_range (35, 34),
> +-             get_affected_range (&dc, hint_2, CU_BYTES));
> ++             get_affected_range (policy, hint_2, CU_BYTES));
> +     ASSERT_EQ (column_range (30, 29),
> +-             get_affected_range (&dc, hint_2, CU_DISPLAY_COLS));
> +-    ASSERT_EQ (column_range (30, 30), get_printed_columns (&dc,
> hint_2));
> ++             get_affected_range (policy, hint_2, CU_DISPLAY_COLS));
> ++    ASSERT_EQ (column_range (30, 30), get_printed_columns (policy,
> hint_2));
> +
> +     /* Add each hint in turn to a line_corrections instance,
> +        and verify that they are consolidated into one correction
> instance
> +        as expected.  */
> +-    line_corrections lc (&dc, tmp.get_filename (), 1);
> ++    line_corrections lc (policy, tmp.get_filename (), 1);
> +
> +     /* The first replace hint by itself.  */
> +     lc.add_hint (hint_0);
> +@@ -4866,15 +5168,16 @@ test_overlapped_fixit_printing_2 (const
> +     richloc.add_fixit_insert_before (col_21, "}");
> +
> +     /* These fixits should be accepted; they can't be
> consolidated.  */
> ++    char_display_policy policy (make_policy (dc, richloc));
> +     ASSERT_EQ (2, richloc.get_num_fixit_hints ());
> +     const fixit_hint *hint_0 = richloc.get_fixit_hint (0);
> +     ASSERT_EQ (column_range (23, 22),
> +-             get_affected_range (&dc, hint_0, CU_BYTES));
> +-    ASSERT_EQ (column_range (23, 23), get_printed_columns (&dc,
> hint_0));
> ++             get_affected_range (policy, hint_0, CU_BYTES));
> ++    ASSERT_EQ (column_range (23, 23), get_printed_columns (policy,
> hint_0));
> +     const fixit_hint *hint_1 = richloc.get_fixit_hint (1);
> +     ASSERT_EQ (column_range (21, 20),
> +-             get_affected_range (&dc, hint_1, CU_BYTES));
> +-    ASSERT_EQ (column_range (21, 21), get_printed_columns (&dc,
> hint_1));
> ++             get_affected_range (policy, hint_1, CU_BYTES));
> ++    ASSERT_EQ (column_range (21, 21), get_printed_columns (policy,
> hint_1));
> +
> +     /* Verify that they're printed correctly.  */
> +     diagnostic_show_locus (&dc, &richloc, DK_ERROR);
> +@@ -5141,10 +5444,11 @@ test_tab_expansion (const line_table_cas
> +      ....................123 45678901234 56789012345  columns  */
> +
> +   const int tabstop = 8;
> ++  cpp_char_column_policy policy (tabstop, cpp_wcwidth);
> +   const int first_non_ws_byte_col = 7;
> +   const int right_quote_byte_col = 15;
> +   const int last_byte_col = 25;
> +-  ASSERT_EQ (35, cpp_display_width (content, last_byte_col,
> tabstop));
> ++  ASSERT_EQ (35, cpp_display_width (content, last_byte_col,
> policy));
> +
> +   temp_source_file tmp (SELFTEST_LOCATION, ".c", content);
> +   line_table_test ltt (case_);
> +@@ -5187,6 +5491,114 @@ test_tab_expansion (const line_table_cas
> +   }
> + }
> +
> ++/* Verify that the escaping machinery can cope with a variety of
> different
> ++   invalid bytes.  */
> ++
> ++static void
> ++test_escaping_bytes_1 (const line_table_case &case_)
> ++{
> ++  const char content[] = "before\0\1\2\3\r\x80\xff""after\n";
> ++  const size_t sz = sizeof (content);
> ++  temp_source_file tmp (SELFTEST_LOCATION, ".c", content, sz);
> ++  line_table_test ltt (case_);
> ++  const line_map_ordinary *ord_map = linemap_check_ordinary
> ++    (linemap_add (line_table, LC_ENTER, false, tmp.get_filename (),
> 0));
> ++  linemap_line_start (line_table, 1, 100);
> ++
> ++  location_t finish
> ++    = linemap_position_for_line_and_column (line_table, ord_map, 1,
> ++                                          strlen (content));
> ++
> ++  if (finish > LINE_MAP_MAX_LOCATION_WITH_COLS)
> ++    return;
> ++
> ++  /* Locations of the NUL and \r bytes.  */
> ++  location_t nul_loc
> ++    = linemap_position_for_line_and_column (line_table, ord_map, 1,
> 7);
> ++  location_t r_loc
> ++    = linemap_position_for_line_and_column (line_table, ord_map, 1,
> 11);
> ++  gcc_rich_location richloc (nul_loc);
> ++  richloc.add_range (r_loc);
> ++
> ++  {
> ++    test_diagnostic_context dc;
> ++    diagnostic_show_locus (&dc, &richloc, DK_ERROR);
> ++    ASSERT_STREQ (" before \1\2\3 \x80\xff""after\n"
> ++                "       ^   ~\n",
> ++                pp_formatted_text (dc.printer));
> ++  }
> ++  richloc.set_escape_on_output (true);
> ++  {
> ++    test_diagnostic_context dc;
> ++    dc.escape_format = DIAGNOSTICS_ESCAPE_FORMAT_UNICODE;
> ++    diagnostic_show_locus (&dc, &richloc, DK_ERROR);
> ++    ASSERT_STREQ
> ++      ("
> before<U+0000><U+0001><U+0002><U+0003><U+000D><80><ff>after\n"
> ++       "       ^~~~~~~~                        ~~~~~~~~\n",
> ++       pp_formatted_text (dc.printer));
> ++  }
> ++  {
> ++    test_diagnostic_context dc;
> ++    dc.escape_format = DIAGNOSTICS_ESCAPE_FORMAT_BYTES;
> ++    diagnostic_show_locus (&dc, &richloc, DK_ERROR);
> ++    ASSERT_STREQ (" before<00><01><02><03><0d><80><ff>after\n"
> ++                "       ^~~~            ~~~~\n",
> ++                pp_formatted_text (dc.printer));
> ++  }
> ++}
> ++
> ++/* As above, but verify that we handle the initial byte of a line
> ++   correctly.  */
> ++
> ++static void
> ++test_escaping_bytes_2 (const line_table_case &case_)
> ++{
> ++  const char content[]  = "\0after\n";
> ++  const size_t sz = sizeof (content);
> ++  temp_source_file tmp (SELFTEST_LOCATION, ".c", content, sz);
> ++  line_table_test ltt (case_);
> ++  const line_map_ordinary *ord_map = linemap_check_ordinary
> ++    (linemap_add (line_table, LC_ENTER, false, tmp.get_filename (),
> 0));
> ++  linemap_line_start (line_table, 1, 100);
> ++
> ++  location_t finish
> ++    = linemap_position_for_line_and_column (line_table, ord_map, 1,
> ++                                          strlen (content));
> ++
> ++  if (finish > LINE_MAP_MAX_LOCATION_WITH_COLS)
> ++    return;
> ++
> ++  /* Location of the NUL byte.  */
> ++  location_t nul_loc
> ++    = linemap_position_for_line_and_column (line_table, ord_map, 1,
> 1);
> ++  gcc_rich_location richloc (nul_loc);
> ++
> ++  {
> ++    test_diagnostic_context dc;
> ++    diagnostic_show_locus (&dc, &richloc, DK_ERROR);
> ++    ASSERT_STREQ ("  after\n"
> ++                " ^\n",
> ++                pp_formatted_text (dc.printer));
> ++  }
> ++  richloc.set_escape_on_output (true);
> ++  {
> ++    test_diagnostic_context dc;
> ++    dc.escape_format = DIAGNOSTICS_ESCAPE_FORMAT_UNICODE;
> ++    diagnostic_show_locus (&dc, &richloc, DK_ERROR);
> ++    ASSERT_STREQ (" <U+0000>after\n"
> ++                " ^~~~~~~~\n",
> ++                pp_formatted_text (dc.printer));
> ++  }
> ++  {
> ++    test_diagnostic_context dc;
> ++    dc.escape_format = DIAGNOSTICS_ESCAPE_FORMAT_BYTES;
> ++    diagnostic_show_locus (&dc, &richloc, DK_ERROR);
> ++    ASSERT_STREQ (" <00>after\n"
> ++                " ^~~~\n",
> ++                pp_formatted_text (dc.printer));
> ++  }
> ++}
> ++
> + /* Verify that line numbers are correctly printed for the case of
> +    a multiline range in which the width of the line numbers changes
> +    (e.g. from "9" to "10").  */
> +@@ -5243,6 +5655,8 @@ diagnostic_show_locus_c_tests ()
> +   test_layout_range_for_single_line ();
> +   test_layout_range_for_multiple_lines ();
> +
> ++  test_display_widths ();
> ++
> +   for_each_line_table_case (test_layout_x_offset_display_utf8);
> +   for_each_line_table_case (test_layout_x_offset_display_tab);
> +
> +@@ -5263,6 +5677,8 @@ diagnostic_show_locus_c_tests ()
> +   for_each_line_table_case (test_fixit_replace_containing_newline);
> +   for_each_line_table_case (test_fixit_deletion_affecting_newline);
> +   for_each_line_table_case (test_tab_expansion);
> ++  for_each_line_table_case (test_escaping_bytes_1);
> ++  for_each_line_table_case (test_escaping_bytes_2);
> +
> +   test_line_numbers_multiline_range ();
> + }
> +diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> +--- a/gcc/doc/invoke.texi      2021-12-25 01:29:12.927317174 -0800
> ++++ b/gcc/doc/invoke.texi      2021-12-25 01:30:50.681688823 -0800
> +@@ -295,7 +295,8 @@ Objective-C and Objective-C++ Dialects}.
> + -fdiagnostics-show-path-depths @gol
> + -fno-show-column @gol
> + -fdiagnostics-column-unit=@r{[}display@r{|}byte@r{]} @gol
> +--fdiagnostics-column-origin=@var{origin}}
> ++-fdiagnostics-column-origin=@var{origin} @gol
> ++-fdiagnostics-escape-format=@r{[}unicode@r{|}bytes@r{]}}
> +
> + @item Warning Options
> + @xref{Warning Options,,Options to Request or Suppress Warnings}.
> +@@ -4451,6 +4452,38 @@ first column.  The default value of 1 co
> + behavior and to the GNU style guide.  Some utilities may perform
> better with an
> + origin of 0; any non-negative value may be specified.
> +
> ++@item -fdiagnostics-escape-format=@var{FORMAT}
> ++@opindex fdiagnostics-escape-format
> ++When GCC prints pertinent source lines for a diagnostic it normally
> attempts
> ++to print the source bytes directly.  However, some diagnostics
> relate to encoding
> ++issues in the source file, such as malformed UTF-8, or issues with
> Unicode
> ++normalization.  These diagnostics are flagged so that GCC will
> escape bytes
> ++that are not printable ASCII when printing their pertinent source
> lines.
> ++
> ++This option controls how such bytes should be escaped.
> ++
> ++The default @var{FORMAT}, @samp{unicode} displays Unicode
> characters that
> ++are not printable ASCII in the form @samp{<U+XXXX>}, and bytes that
> do not
> ++correspond to a Unicode character validly-encoded in UTF-8-encoded
> will be
> ++displayed as hexadecimal in the form @samp{<XX>}.
> ++
> ++For example, a source line containing the string @samp{before}
> followed by the
> ++Unicode character U+03C0 (``GREEK SMALL LETTER PI'', with UTF-8
> encoding
> ++0xCF 0x80) followed by the byte 0xBF (a stray UTF-8 trailing byte),
> followed by
> ++the string @samp{after} will be printed for such a diagnostic as:
> ++
> ++@smallexample
> ++ before<U+03C0><BF>after
> ++@end smallexample
> ++
> ++Setting @var{FORMAT} to @samp{bytes} will display all non-
> printable-ASCII bytes
> ++in the form @samp{<XX>}, thus showing the underlying encoding of
> non-ASCII
> ++Unicode characters.  For the example above, the following will be
> printed:
> ++
> ++@smallexample
> ++ before<CF><80><BF>after
> ++@end smallexample
> ++
> + @item -fdiagnostics-format=@var{FORMAT}
> + @opindex fdiagnostics-format
> + Select a different format for printing diagnostics.
> +@@ -4518,9 +4551,11 @@ might be printed in JSON form (after for
> +                         @}
> +                     @}
> +                 ],
> ++                "escape-source": false,
> +                 "message": "...this statement, but the latter is
> @dots{}"
> +             @}
> +         ]
> ++      "escape-source": false,
> +       "column-origin": 1,
> +     @},
> +     @dots{}
> +@@ -4607,6 +4642,7 @@ of the expression, which have labels.  I
> +                 "label": "T @{aka struct t@}"
> +             @}
> +         ],
> ++        "escape-source": false,
> +         "message": "invalid operands to binary + @dots{}"
> +     @}
> + @end smallexample
> +@@ -4660,6 +4696,7 @@ might be printed in JSON form as:
> +                 @}
> +             @}
> +         ],
> ++        "escape-source": false,
> +         "message": "\u2018struct s\u2019 has no member named
> @dots{}"
> +     @}
> + @end smallexample
> +@@ -4717,6 +4754,10 @@ For example, the intraprocedural example
> +     ]
> + @end smallexample
> +
> ++Diagnostics have a boolean attribute @code{escape-source}, hinting
> whether
> ++non-ASCII bytes should be escaped when printing the pertinent lines
> of
> ++source code (@code{true} for diagnostics involving source encoding
> issues).
> ++
> + @end table
> +
> + @node Warning Options
> +diff --git a/gcc/input.c b/gcc/input.c
> +--- a/gcc/input.c      2021-12-25 01:29:12.927317174 -0800
> ++++ b/gcc/input.c      2021-12-25 01:30:50.681688823 -0800
> +@@ -913,7 +913,8 @@ make_location (location_t caret, source_
> +    source line in order to calculate the display width.  If that
> cannot be done
> +    for any reason, then returns the byte column as a fallback.  */
> + int
> +-location_compute_display_column (expanded_location exploc, int
> tabstop)
> ++location_compute_display_column (expanded_location exploc,
> ++                               const cpp_char_column_policy
> &policy)
> + {
> +   if (!(exploc.file && *exploc.file && exploc.line &&
> exploc.column))
> +     return exploc.column;
> +@@ -921,7 +922,7 @@ location_compute_display_column (expande
> +   /* If line is NULL, this function returns exploc.column which is
> the
> +      desired fallback.  */
> +   return cpp_byte_column_to_display_column (line.get_buffer (),
> line.length (),
> +-                                          exploc.column, tabstop);
> ++                                          exploc.column, policy);
> + }
> +
> + /* Dump statistics to stderr about the memory usage of the
> line_table
> +@@ -3609,43 +3610,50 @@ test_line_offset_overflow ()
> + void test_cpp_utf8 ()
> + {
> +   const int def_tabstop = 8;
> ++  cpp_char_column_policy policy (def_tabstop, cpp_wcwidth);
> ++
> +   /* Verify that wcwidth of invalid UTF-8 or control bytes is 1.
> */
> +   {
> +-    int w_bad = cpp_display_width ("\xf0!\x9f!\x98!\x82!", 8,
> def_tabstop);
> ++    int w_bad = cpp_display_width ("\xf0!\x9f!\x98!\x82!", 8,
> policy);
> +     ASSERT_EQ (8, w_bad);
> +-    int w_ctrl = cpp_display_width ("\r\n\v\0\1", 5, def_tabstop);
> ++    int w_ctrl = cpp_display_width ("\r\n\v\0\1", 5, policy);
> +     ASSERT_EQ (5, w_ctrl);
> +   }
> +
> +   /* Verify that wcwidth of valid UTF-8 is as expected.  */
> +   {
> +-    const int w_pi = cpp_display_width ("\xcf\x80", 2,
> def_tabstop);
> ++    const int w_pi = cpp_display_width ("\xcf\x80", 2, policy);
> +     ASSERT_EQ (1, w_pi);
> +-    const int w_emoji = cpp_display_width ("\xf0\x9f\x98\x82", 4,
> def_tabstop);
> ++    const int w_emoji = cpp_display_width ("\xf0\x9f\x98\x82", 4,
> policy);
> +     ASSERT_EQ (2, w_emoji);
> +     const int w_umlaut_precomposed = cpp_display_width ("\xc3\xbf",
> 2,
> +-                                                      def_tabstop);
> ++                                                      policy);
> +     ASSERT_EQ (1, w_umlaut_precomposed);
> +     const int w_umlaut_combining = cpp_display_width ("y\xcc\x88",
> 3,
> +-                                                    def_tabstop);
> ++                                                    policy);
> +     ASSERT_EQ (1, w_umlaut_combining);
> +-    const int w_han = cpp_display_width ("\xe4\xb8\xba", 3,
> def_tabstop);
> ++    const int w_han = cpp_display_width ("\xe4\xb8\xba", 3,
> policy);
> +     ASSERT_EQ (2, w_han);
> +-    const int w_ascii = cpp_display_width ("GCC", 3, def_tabstop);
> ++    const int w_ascii = cpp_display_width ("GCC", 3, policy);
> +     ASSERT_EQ (3, w_ascii);
> +     const int w_mixed = cpp_display_width ("\xcf\x80 = 3.14
> \xf0\x9f\x98\x82"
> +                                          "\x9f! \xe4\xb8\xba
> y\xcc\x88",
> +-                                         24, def_tabstop);
> ++                                         24, policy);
> +     ASSERT_EQ (18, w_mixed);
> +   }
> +
> +   /* Verify that display width properly expands tabs.  */
> +   {
> +     const char *tstr = "\tabc\td";
> +-    ASSERT_EQ (6, cpp_display_width (tstr, 6, 1));
> +-    ASSERT_EQ (10, cpp_display_width (tstr, 6, 3));
> +-    ASSERT_EQ (17, cpp_display_width (tstr, 6, 8));
> +-    ASSERT_EQ (1, cpp_display_column_to_byte_column (tstr, 6, 7,
> 8));
> ++    ASSERT_EQ (6, cpp_display_width (tstr, 6,
> ++                                   cpp_char_column_policy (1,
> cpp_wcwidth)));
> ++    ASSERT_EQ (10, cpp_display_width (tstr, 6,
> ++                                    cpp_char_column_policy (3,
> cpp_wcwidth)));
> ++    ASSERT_EQ (17, cpp_display_width (tstr, 6,
> ++                                    cpp_char_column_policy (8,
> cpp_wcwidth)));
> ++    ASSERT_EQ (1,
> ++             cpp_display_column_to_byte_column
> ++               (tstr, 6, 7, cpp_char_column_policy (8,
> cpp_wcwidth)));
> +   }
> +
> +   /* Verify that cpp_byte_column_to_display_column can go past the
> end,
> +@@ -3658,13 +3666,13 @@ void test_cpp_utf8 ()
> +       /* 111122223456
> +        Byte columns.  */
> +
> +-    ASSERT_EQ (5, cpp_display_width (str, 6, def_tabstop));
> ++    ASSERT_EQ (5, cpp_display_width (str, 6, policy));
> +     ASSERT_EQ (105,
> +-             cpp_byte_column_to_display_column (str, 6, 106,
> def_tabstop));
> ++             cpp_byte_column_to_display_column (str, 6, 106,
> policy));
> +     ASSERT_EQ (10000,
> +-             cpp_byte_column_to_display_column (NULL, 0, 10000,
> def_tabstop));
> ++             cpp_byte_column_to_display_column (NULL, 0, 10000,
> policy));
> +     ASSERT_EQ (0,
> +-             cpp_byte_column_to_display_column (NULL, 10000, 0,
> def_tabstop));
> ++             cpp_byte_column_to_display_column (NULL, 10000, 0,
> policy));
> +   }
> +
> +   /* Verify that cpp_display_column_to_byte_column can go past the
> end,
> +@@ -3678,25 +3686,25 @@ void test_cpp_utf8 ()
> +       /* 000000000000000000000000000000000111111
> +        111122223333444456666777788889999012345
> +        Byte columns.  */
> +-    ASSERT_EQ (4, cpp_display_column_to_byte_column (str, 15, 2,
> def_tabstop));
> ++    ASSERT_EQ (4, cpp_display_column_to_byte_column (str, 15, 2,
> policy));
> +     ASSERT_EQ (15,
> +-             cpp_display_column_to_byte_column (str, 15, 11,
> def_tabstop));
> ++             cpp_display_column_to_byte_column (str, 15, 11,
> policy));
> +     ASSERT_EQ (115,
> +-             cpp_display_column_to_byte_column (str, 15, 111,
> def_tabstop));
> ++             cpp_display_column_to_byte_column (str, 15, 111,
> policy));
> +     ASSERT_EQ (10000,
> +-             cpp_display_column_to_byte_column (NULL, 0, 10000,
> def_tabstop));
> ++             cpp_display_column_to_byte_column (NULL, 0, 10000,
> policy));
> +     ASSERT_EQ (0,
> +-             cpp_display_column_to_byte_column (NULL, 10000, 0,
> def_tabstop));
> ++             cpp_display_column_to_byte_column (NULL, 10000, 0,
> policy));
> +
> +     /* Verify that we do not interrupt a UTF-8 sequence.  */
> +-    ASSERT_EQ (4, cpp_display_column_to_byte_column (str, 15, 1,
> def_tabstop));
> ++    ASSERT_EQ (4, cpp_display_column_to_byte_column (str, 15, 1,
> policy));
> +
> +     for (int byte_col = 1; byte_col <= 15; ++byte_col)
> +       {
> +       const int disp_col
> +-        = cpp_byte_column_to_display_column (str, 15, byte_col,
> def_tabstop);
> ++        = cpp_byte_column_to_display_column (str, 15, byte_col,
> policy);
> +       const int byte_col2
> +-        = cpp_display_column_to_byte_column (str, 15, disp_col,
> def_tabstop);
> ++        = cpp_display_column_to_byte_column (str, 15, disp_col,
> policy);
> +
> +       /* If we ask for the display column in the middle of a UTF-8
> +          sequence, it will return the length of the partial
> sequence,
> +diff --git a/gcc/input.h b/gcc/input.h
> +--- a/gcc/input.h      2021-12-25 01:29:12.927317174 -0800
> ++++ b/gcc/input.h      2021-12-25 01:30:50.681688823 -0800
> +@@ -39,8 +39,11 @@ STATIC_ASSERT (BUILTINS_LOCATION < RESER
> + extern bool is_location_from_builtin_token (location_t);
> + extern expanded_location expand_location (location_t);
> +
> +-extern int location_compute_display_column (expanded_location
> exploc,
> +-                                          int tabstop);
> ++class cpp_char_column_policy;
> ++
> ++extern int
> ++location_compute_display_column (expanded_location exploc,
> ++                               const cpp_char_column_policy
> &policy);
> +
> + /* A class capturing the bounds of a buffer, to allow for run-time
> +    bounds-checking in a checked build.  */
> +diff --git a/gcc/opts.c b/gcc/opts.c
> +--- a/gcc/opts.c       2021-12-25 01:29:12.927317174 -0800
> ++++ b/gcc/opts.c       2021-12-25 01:30:50.681688823 -0800
> +@@ -2447,6 +2447,10 @@ common_handle_option (struct gcc_options
> +       dc->column_origin = value;
> +       break;
> +
> ++    case OPT_fdiagnostics_escape_format_:
> ++      dc->escape_format = (enum diagnostics_escape_format)value;
> ++      break;
> ++
> +     case OPT_fdiagnostics_show_cwe:
> +       dc->show_cwe = value;
> +       break;
> +diff --git a/gcc/selftest.c b/gcc/selftest.c
> +--- a/gcc/selftest.c   2020-07-22 23:35:17.820389797 -0700
> ++++ b/gcc/selftest.c   2021-12-25 01:30:50.681688823 -0800
> +@@ -193,6 +193,21 @@ temp_source_file::temp_source_file (cons
> +   fclose (out);
> + }
> +
> ++/* As above, but with a size, to allow for NUL bytes in CONTENT.
> */
> ++
> ++temp_source_file::temp_source_file (const location &loc,
> ++                                  const char *suffix,
> ++                                  const char *content,
> ++                                  size_t sz)
> ++: named_temp_file (suffix)
> ++{
> ++  FILE *out = fopen (get_filename (), "w");
> ++  if (!out)
> ++    fail_formatted (loc, "unable to open tempfile: %s",
> get_filename ());
> ++  fwrite (content, sz, 1, out);
> ++  fclose (out);
> ++}
> ++
> + /* Avoid introducing locale-specific differences in the results
> +    by hardcoding open_quote and close_quote.  */
> +
> +diff --git a/gcc/selftest.h b/gcc/selftest.h
> +--- a/gcc/selftest.h   2020-07-22 23:35:17.820389797 -0700
> ++++ b/gcc/selftest.h   2021-12-25 01:30:50.681688823 -0800
> +@@ -112,6 +112,8 @@ class temp_source_file : public named_te
> +  public:
> +   temp_source_file (const location &loc, const char *suffix,
> +                   const char *content);
> ++  temp_source_file (const location &loc, const char *suffix,
> ++                  const char *content, size_t sz);
> + };
> +
> + /* RAII-style class for avoiding introducing locale-specific
> differences
> +diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-1.c
> b/gcc/testsuite/c-c++-common/diagnostic-format-json-1.c
> +--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-1.c    2021-
> 12-25 01:29:12.927317174 -0800
> ++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-1.c    2021-
> 12-25 01:30:50.681688823 -0800
> +@@ -9,6 +9,7 @@
> +
> + /* { dg-regexp "\"kind\": \"error\"" } */
> + /* { dg-regexp "\"column-origin\": 1" } */
> ++/* { dg-regexp "\"escape-source\": false" } */
> + /* { dg-regexp "\"message\": \"#error message\"" } */
> +
> + /* { dg-regexp "\"caret\": \{" } */
> +diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-2.c
> b/gcc/testsuite/c-c++-common/diagnostic-format-json-2.c
> +--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-2.c    2021-
> 12-25 01:29:12.927317174 -0800
> ++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-2.c    2021-
> 12-25 01:30:50.681688823 -0800
> +@@ -9,6 +9,7 @@
> +
> + /* { dg-regexp "\"kind\": \"warning\"" } */
> + /* { dg-regexp "\"column-origin\": 1" } */
> ++/* { dg-regexp "\"escape-source\": false" } */
> + /* { dg-regexp "\"message\": \"#warning message\"" } */
> + /* { dg-regexp "\"option\": \"-Wcpp\"" } */
> + /* { dg-regexp "\"option_url\": \"https:\[^\n\r\"\]*#index-Wcpp\""
> } */
> +diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-3.c
> b/gcc/testsuite/c-c++-common/diagnostic-format-json-3.c
> +--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-3.c    2021-
> 12-25 01:29:12.927317174 -0800
> ++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-3.c    2021-
> 12-25 01:30:50.681688823 -0800
> +@@ -9,6 +9,7 @@
> +
> + /* { dg-regexp "\"kind\": \"error\"" } */
> + /* { dg-regexp "\"column-origin\": 1" } */
> ++/* { dg-regexp "\"escape-source\": false" } */
> + /* { dg-regexp "\"message\": \"#warning message\"" } */
> + /* { dg-regexp "\"option\": \"-Werror=cpp\"" } */
> + /* { dg-regexp "\"option_url\": \"https:\[^\n\r\"\]*#index-Wcpp\""
> } */
> +diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-4.c
> b/gcc/testsuite/c-c++-common/diagnostic-format-json-4.c
> +--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-4.c    2021-
> 12-25 01:29:12.927317174 -0800
> ++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-4.c    2021-
> 12-25 01:30:50.681688823 -0800
> +@@ -19,6 +19,7 @@ int test (void)
> +
> + /* { dg-regexp "\"kind\": \"note\"" } */
> + /* { dg-regexp "\"message\": \"...this statement, but the latter is
> misleadingly indented as if it were guarded by the 'if'\"" } */
> ++/* { dg-regexp "\"escape-source\": false" } */
> +
> + /* { dg-regexp "\"caret\": \{" } */
> + /* { dg-regexp "\"file\": \"\[^\n\r\"\]*diagnostic-format-json-
> 4.c\"" } */
> +@@ -39,6 +40,7 @@ int test (void)
> + /* { dg-regexp "\"kind\": \"warning\"" } */
> + /* { dg-regexp "\"column-origin\": 1" } */
> + /* { dg-regexp "\"message\": \"this 'if' clause does not
> guard...\"" } */
> ++/* { dg-regexp "\"escape-source\": false" } */
> + /* { dg-regexp "\"option\": \"-Wmisleading-indentation\"" } */
> + /* { dg-regexp "\"option_url\": \"https:\[^\n\r\"\]*#index-
> Wmisleading-indentation\"" } */
> +
> +diff --git a/gcc/testsuite/c-c++-common/diagnostic-format-json-5.c
> b/gcc/testsuite/c-c++-common/diagnostic-format-json-5.c
> +--- a/gcc/testsuite/c-c++-common/diagnostic-format-json-5.c    2021-
> 12-25 01:29:12.927317174 -0800
> ++++ b/gcc/testsuite/c-c++-common/diagnostic-format-json-5.c    2021-
> 12-25 01:30:50.681688823 -0800
> +@@ -14,6 +14,7 @@ int test (struct s *ptr)
> +
> + /* { dg-regexp "\"kind\": \"error\"" } */
> + /* { dg-regexp "\"column-origin\": 1" } */
> ++/* { dg-regexp "\"escape-source\": false" } */
> + /* { dg-regexp "\"message\": \".*\"" } */
> +
> + /* Verify fix-it hints.  */
> +diff --git a/gcc/testsuite/gcc.dg/cpp/warn-normalized-4-bytes.c
> b/gcc/testsuite/gcc.dg/cpp/warn-normalized-4-bytes.c
> +--- a/gcc/testsuite/gcc.dg/cpp/warn-normalized-4-bytes.c       1969-
> 12-31 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/gcc.dg/cpp/warn-normalized-4-bytes.c       2021-
> 12-25 01:30:50.681688823 -0800
> +@@ -0,0 +1,21 @@
> ++// { dg-do preprocess }
> ++// { dg-options "-std=gnu99 -Werror=normalized=nfc -fdiagnostics-
> show-caret -fdiagnostics-escape-format=bytes" }
> ++/* { dg-message "some warnings being treated as errors" "" {target
> "*-*-*"} 0 } */
> ++
> ++/* à½ = U+0F43 TIBETAN LETTER GHA, which has decomposition "0F42
> 0FB7" i.e.
> ++   U+0F42 TIBETAN LETTER GA: à½
> ++   U+0FB7 TIBETAN SUBJOINED LETTER HA: à¾·
> ++
> ++   The UTF-8 encoding of U+0F43 TIBETAN LETTER GHA is: E0 BD 83.
> */
> ++
> ++foo before_\u0F43_after bar // { dg-error
> "`before_.U00000f43_after' is not in NFC .-Werror=normalized=." }
> ++/* { dg-begin-multiline-output "" }
> ++ foo before_\u0F43_after bar
> ++     ^~~~~~~~~~~~~~~~~~~
> ++   { dg-end-multiline-output "" } */
> ++
> ++foo before_à½_after bar // { dg-error "`before_.U00000f43_after' is
> not in NFC .-Werror=normalized=." }
> ++/* { dg-begin-multiline-output "" }
> ++ foo before_<e0><bd><83>_after bar
> ++     ^~~~~~~~~~~~~~~~~~~~~~~~~
> ++   { dg-end-multiline-output "" } */
> +diff --git a/gcc/testsuite/gcc.dg/cpp/warn-normalized-4-unicode.c
> b/gcc/testsuite/gcc.dg/cpp/warn-normalized-4-unicode.c
> +--- a/gcc/testsuite/gcc.dg/cpp/warn-normalized-4-unicode.c     1969-
> 12-31 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/gcc.dg/cpp/warn-normalized-4-unicode.c     2021-
> 12-25 01:30:50.681688823 -0800
> +@@ -0,0 +1,19 @@
> ++// { dg-do preprocess }
> ++// { dg-options "-std=gnu99 -Werror=normalized=nfc -fdiagnostics-
> show-caret -fdiagnostics-escape-format=unicode" }
> ++/* { dg-message "some warnings being treated as errors" "" {target
> "*-*-*"} 0 } */
> ++
> ++/* à½ = U+0F43 TIBETAN LETTER GHA, which has decomposition "0F42
> 0FB7" i.e.
> ++   U+0F42 TIBETAN LETTER GA: à½
> ++   U+0FB7 TIBETAN SUBJOINED LETTER HA: à¾·  */
> ++
> ++foo before_\u0F43_after bar  // { dg-error
> "`before_.U00000f43_after' is not in NFC .-Werror=normalized=." }
> ++/* { dg-begin-multiline-output "" }
> ++ foo before_\u0F43_after bar
> ++     ^~~~~~~~~~~~~~~~~~~
> ++   { dg-end-multiline-output "" } */
> ++
> ++foo before_à½_after bar // { dg-error "`before_.U00000f43_after' is
> not in NFC .-Werror=normalized=." }
> ++/* { dg-begin-multiline-output "" }
> ++ foo before_<U+0F43>_after bar
> ++     ^~~~~~~~~~~~~~~~~~~~~
> ++   { dg-end-multiline-output "" } */
> +diff --git a/gcc/testsuite/gfortran.dg/diagnostic-format-json-1.F90
> b/gcc/testsuite/gfortran.dg/diagnostic-format-json-1.F90
> +--- a/gcc/testsuite/gfortran.dg/diagnostic-format-json-1.F90   2021-
> 12-25 01:29:12.931317107 -0800
> ++++ b/gcc/testsuite/gfortran.dg/diagnostic-format-json-1.F90   2021-
> 12-25 01:30:50.681688823 -0800
> +@@ -9,6 +9,7 @@
> +
> + ! { dg-regexp "\"kind\": \"error\"" }
> + ! { dg-regexp "\"column-origin\": 1" }
> ++! { dg-regexp "\"escape-source\": false" }
> + ! { dg-regexp "\"message\": \"#error message\"" }
> +
> + ! { dg-regexp "\"caret\": \{" }
> +diff --git a/gcc/testsuite/gfortran.dg/diagnostic-format-json-2.F90
> b/gcc/testsuite/gfortran.dg/diagnostic-format-json-2.F90
> +--- a/gcc/testsuite/gfortran.dg/diagnostic-format-json-2.F90   2021-
> 12-25 01:29:12.931317107 -0800
> ++++ b/gcc/testsuite/gfortran.dg/diagnostic-format-json-2.F90   2021-
> 12-25 01:30:50.681688823 -0800
> +@@ -9,6 +9,7 @@
> +
> + ! { dg-regexp "\"kind\": \"warning\"" }
> + ! { dg-regexp "\"column-origin\": 1" }
> ++! { dg-regexp "\"escape-source\": false" }
> + ! { dg-regexp "\"message\": \"#warning message\"" }
> + ! { dg-regexp "\"option\": \"-Wcpp\"" }
> + ! { dg-regexp "\"option_url\": \"\[^\n\r\"\]*#index-Wcpp\"" }
> +diff --git a/gcc/testsuite/gfortran.dg/diagnostic-format-json-3.F90
> b/gcc/testsuite/gfortran.dg/diagnostic-format-json-3.F90
> +--- a/gcc/testsuite/gfortran.dg/diagnostic-format-json-3.F90   2021-
> 12-25 01:29:12.931317107 -0800
> ++++ b/gcc/testsuite/gfortran.dg/diagnostic-format-json-3.F90   2021-
> 12-25 01:30:50.681688823 -0800
> +@@ -9,6 +9,7 @@
> +
> + ! { dg-regexp "\"kind\": \"error\"" }
> + ! { dg-regexp "\"column-origin\": 1" }
> ++! { dg-regexp "\"escape-source\": false" }
> + ! { dg-regexp "\"message\": \"#warning message\"" }
> + ! { dg-regexp "\"option\": \"-Werror=cpp\"" }
> + ! { dg-regexp "\"option_url\": \"\[^\n\r\"\]*#index-Wcpp\"" }
> +diff --git a/libcpp/charset.c b/libcpp/charset.c
> +--- a/libcpp/charset.c 2021-12-25 01:29:12.931317107 -0800
> ++++ b/libcpp/charset.c 2021-12-25 01:30:50.681688823 -0800
> +@@ -1549,12 +1549,14 @@ convert_escape (cpp_reader *pfile, const
> +                  "unknown escape sequence: '\\%c'", (int) c);
> +       else
> +       {
> ++        encoding_rich_location rich_loc (pfile);
> ++
> +         /* diagnostic.c does not support "%03o".  When it does,
> this
> +            code can use %03o directly in the diagnostic again.  */
> +         char buf[32];
> +         sprintf(buf, "%03o", (int) c);
> +-        cpp_error (pfile, CPP_DL_PEDWARN,
> +-                   "unknown escape sequence: '\\%s'", buf);
> ++        cpp_error_at (pfile, CPP_DL_PEDWARN, &rich_loc,
> ++                      "unknown escape sequence: '\\%s'", buf);
> +       }
> +     }
> +
> +@@ -2277,14 +2279,16 @@ cpp_string_location_reader::get_next ()
> + }
> +
> + cpp_display_width_computation::
> +-cpp_display_width_computation (const char *data, int data_length,
> int tabstop) :
> ++cpp_display_width_computation (const char *data, int data_length,
> ++                             const cpp_char_column_policy &policy)
> :
> +   m_begin (data),
> +   m_next (m_begin),
> +   m_bytes_left (data_length),
> +-  m_tabstop (tabstop),
> ++  m_policy (policy),
> +   m_display_cols (0)
> + {
> +-  gcc_assert (m_tabstop > 0);
> ++  gcc_assert (policy.m_tabstop > 0);
> ++  gcc_assert (policy.m_width_cb);
> + }
> +
> +
> +@@ -2296,19 +2300,28 @@ cpp_display_width_computation (const cha
> +    point to a valid UTF-8-encoded sequence, then it will be treated
> as a single
> +    byte with display width 1.  m_cur_display_col is the current
> display column,
> +    relative to which tab stops should be expanded.  Returns the
> display width of
> +-   the codepoint just processed.  */
> ++   the codepoint just processed.
> ++   If OUT is non-NULL, it is populated.  */
> +
> + int
> +-cpp_display_width_computation::process_next_codepoint ()
> ++cpp_display_width_computation::process_next_codepoint
> (cpp_decoded_char *out)
> + {
> +   cppchar_t c;
> +   int next_width;
> +
> ++  if (out)
> ++    out->m_start_byte = m_next;
> ++
> +   if (*m_next == '\t')
> +     {
> +       ++m_next;
> +       --m_bytes_left;
> +-      next_width = m_tabstop - (m_display_cols % m_tabstop);
> ++      next_width = m_policy.m_tabstop - (m_display_cols %
> m_policy.m_tabstop);
> ++      if (out)
> ++      {
> ++        out->m_ch = '\t';
> ++        out->m_valid_ch = true;
> ++      }
> +     }
> +   else if (one_utf8_to_cppchar ((const uchar **) &m_next,
> &m_bytes_left, &c)
> +          != 0)
> +@@ -2318,14 +2331,24 @@ cpp_display_width_computation::process_n
> +        of one.  */
> +       ++m_next;
> +       --m_bytes_left;
> +-      next_width = 1;
> ++      next_width = m_policy.m_undecoded_byte_width;
> ++      if (out)
> ++      out->m_valid_ch = false;
> +     }
> +   else
> +     {
> +       /*  one_utf8_to_cppchar() has updated m_next and m_bytes_left
> for us.  */
> +-      next_width = cpp_wcwidth (c);
> ++      next_width = m_policy.m_width_cb (c);
> ++      if (out)
> ++      {
> ++        out->m_ch = c;
> ++        out->m_valid_ch = true;
> ++      }
> +     }
> +
> ++  if (out)
> ++    out->m_next_byte = m_next;
> ++
> +   m_display_cols += next_width;
> +   return next_width;
> + }
> +@@ -2341,7 +2364,7 @@ cpp_display_width_computation::advance_d
> +   const int start = m_display_cols;
> +   const int target = start + n;
> +   while (m_display_cols < target && !done ())
> +-    process_next_codepoint ();
> ++    process_next_codepoint (NULL);
> +   return m_display_cols - start;
> + }
> +
> +@@ -2349,29 +2372,33 @@ cpp_display_width_computation::advance_d
> +     how many display columns are occupied by the first COLUMN
> bytes.  COLUMN
> +     may exceed DATA_LENGTH, in which case the phantom bytes at the
> end are
> +     treated as if they have display width 1.  Tabs are expanded to
> the next tab
> +-    stop, relative to the start of DATA.  */
> ++    stop, relative to the start of DATA, and non-printable-ASCII
> characters
> ++    will be escaped as per POLICY.  */
> +
> + int
> + cpp_byte_column_to_display_column (const char *data, int
> data_length,
> +-                                 int column, int tabstop)
> ++                                 int column,
> ++                                 const cpp_char_column_policy
> &policy)
> + {
> +   const int offset = MAX (0, column - data_length);
> +-  cpp_display_width_computation dw (data, column - offset,
> tabstop);
> ++  cpp_display_width_computation dw (data, column - offset, policy);
> +   while (!dw.done ())
> +-    dw.process_next_codepoint ();
> ++    dw.process_next_codepoint (NULL);
> +   return dw.display_cols_processed () + offset;
> + }
> +
> + /*  For the string of length DATA_LENGTH bytes that begins at DATA,
> compute
> +     the least number of bytes that will result in at least
> DISPLAY_COL display
> +     columns.  The return value may exceed DATA_LENGTH if the entire
> string does
> +-    not occupy enough display columns.  */
> ++    not occupy enough display columns.  Non-printable-ASCII
> characters
> ++    will be escaped as per POLICY.  */
> +
> + int
> + cpp_display_column_to_byte_column (const char *data, int
> data_length,
> +-                                 int display_col, int tabstop)
> ++                                 int display_col,
> ++                                 const cpp_char_column_policy
> &policy)
> + {
> +-  cpp_display_width_computation dw (data, data_length, tabstop);
> ++  cpp_display_width_computation dw (data, data_length, policy);
> +   const int avail_display = dw.advance_display_cols (display_col);
> +   return dw.bytes_processed () + MAX (0, display_col -
> avail_display);
> + }
> +diff --git a/libcpp/errors.c b/libcpp/errors.c
> +--- a/libcpp/errors.c  2020-07-22 23:35:18.712399623 -0700
> ++++ b/libcpp/errors.c  2021-12-25 01:30:50.681688823 -0800
> +@@ -27,6 +27,31 @@ along with this program; see the file CO
> + #include "cpplib.h"
> + #include "internal.h"
> +
> ++/* Get a location_t for the current location in PFILE,
> ++   generally that of the previously lexed token.  */
> ++
> ++location_t
> ++cpp_diagnostic_get_current_location (cpp_reader *pfile)
> ++{
> ++  if (CPP_OPTION (pfile, traditional))
> ++    {
> ++      if (pfile->state.in_directive)
> ++      return pfile->directive_line;
> ++      else
> ++      return pfile->line_table->highest_line;
> ++    }
> ++  /* We don't want to refer to a token before the beginning of the
> ++     current run -- that is invalid.  */
> ++  else if (pfile->cur_token == pfile->cur_run->base)
> ++    {
> ++      return 0;
> ++    }
> ++  else
> ++    {
> ++      return pfile->cur_token[-1].src_loc;
> ++    }
> ++}
> ++
> + /* Print a diagnostic at the given location.  */
> +
> + ATTRIBUTE_FPTR_PRINTF(5,0)
> +@@ -52,25 +77,7 @@ cpp_diagnostic (cpp_reader * pfile, enum
> +               enum cpp_warning_reason reason,
> +               const char *msgid, va_list *ap)
> + {
> +-  location_t src_loc;
> +-
> +-  if (CPP_OPTION (pfile, traditional))
> +-    {
> +-      if (pfile->state.in_directive)
> +-      src_loc = pfile->directive_line;
> +-      else
> +-      src_loc = pfile->line_table->highest_line;
> +-    }
> +-  /* We don't want to refer to a token before the beginning of the
> +-     current run -- that is invalid.  */
> +-  else if (pfile->cur_token == pfile->cur_run->base)
> +-    {
> +-      src_loc = 0;
> +-    }
> +-  else
> +-    {
> +-      src_loc = pfile->cur_token[-1].src_loc;
> +-    }
> ++  location_t src_loc = cpp_diagnostic_get_current_location (pfile);
> +   rich_location richloc (pfile->line_table, src_loc);
> +   return cpp_diagnostic_at (pfile, level, reason, &richloc, msgid,
> ap);
> + }
> +@@ -142,6 +149,43 @@ cpp_warning_syshdr (cpp_reader * pfile,
> +
> +   va_end (ap);
> +   return ret;
> ++}
> ++
> ++/* As cpp_warning above, but use RICHLOC as the location of the
> diagnostic.  */
> ++
> ++bool cpp_warning_at (cpp_reader *pfile, enum cpp_warning_reason
> reason,
> ++                   rich_location *richloc, const char *msgid, ...)
> ++{
> ++  va_list ap;
> ++  bool ret;
> ++
> ++  va_start (ap, msgid);
> ++
> ++  ret = cpp_diagnostic_at (pfile, CPP_DL_WARNING, reason, richloc,
> ++                         msgid, &ap);
> ++
> ++  va_end (ap);
> ++  return ret;
> ++
> ++}
> ++
> ++/* As cpp_pedwarning above, but use RICHLOC as the location of the
> ++   diagnostic.  */
> ++
> ++bool
> ++cpp_pedwarning_at (cpp_reader * pfile, enum cpp_warning_reason
> reason,
> ++                 rich_location *richloc, const char *msgid, ...)
> ++{
> ++  va_list ap;
> ++  bool ret;
> ++
> ++  va_start (ap, msgid);
> ++
> ++  ret = cpp_diagnostic_at (pfile, CPP_DL_PEDWARN, reason, richloc,
> ++                         msgid, &ap);
> ++
> ++  va_end (ap);
> ++  return ret;
> + }
> +
> + /* Print a diagnostic at a specific location.  */
> +diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
> +--- a/libcpp/include/cpplib.h  2021-12-25 01:29:12.931317107 -0800
> ++++ b/libcpp/include/cpplib.h  2021-12-25 01:30:50.685688757 -0800
> +@@ -1176,6 +1176,14 @@ extern bool cpp_warning_syshdr (cpp_read
> +                               const char *msgid, ...)
> +   ATTRIBUTE_PRINTF_3;
> +
> ++/* As their counterparts above, but use RICHLOC.  */
> ++extern bool cpp_warning_at (cpp_reader *, enum cpp_warning_reason,
> ++                          rich_location *richloc, const char
> *msgid, ...)
> ++  ATTRIBUTE_PRINTF_4;
> ++extern bool cpp_pedwarning_at (cpp_reader *, enum
> cpp_warning_reason,
> ++                             rich_location *richloc, const char
> *msgid, ...)
> ++  ATTRIBUTE_PRINTF_4;
> ++
> + /* Output a diagnostic with "MSGID: " preceding the
> +    error string of errno.  No location is printed.  */
> + extern bool cpp_errno (cpp_reader *, enum cpp_diagnostic_level,
> +@@ -1320,42 +1328,95 @@ extern const char * cpp_get_userdef_suff
> +
> + /* In charset.c */
> +
> ++/* The result of attempting to decode a run of UTF-8 bytes.  */
> ++
> ++struct cpp_decoded_char
> ++{
> ++  const char *m_start_byte;
> ++  const char *m_next_byte;
> ++
> ++  bool m_valid_ch;
> ++  cppchar_t m_ch;
> ++};
> ++
> ++/* Information for mapping between code points and display columns.
> ++
> ++   This is a tabstop value, along with a callback for getting the
> ++   widths of characters.  Normally this callback is cpp_wcwidth,
> but we
> ++   support other schemes for escaping non-ASCII unicode as a series
> of
> ++   ASCII chars when printing the user's source code in diagnostic-
> show-locus.c
> ++
> ++   For example, consider:
> ++   - the Unicode character U+03C0 "GREEK SMALL LETTER PI" (UTF-8:
> 0xCF 0x80)
> ++   - the Unicode character U+1F642 "SLIGHTLY SMILING FACE"
> ++     (UTF-8: 0xF0 0x9F 0x99 0x82)
> ++   - the byte 0xBF (a stray trailing byte of a UTF-8 character)
> ++   Normally U+03C0 would occupy one display column, U+1F642
> ++   would occupy two display columns, and the stray byte would be
> ++   printed verbatim as one display column.
> ++
> ++   However when escaping them as unicode code points as "<U+03C0>"
> ++   and "<U+1F642>" they occupy 8 and 9 display columns
> respectively,
> ++   and when escaping them as bytes as "<CF><80>" and
> "<F0><9F><99><82>"
> ++   they occupy 8 and 16 display columns respectively.  In both
> cases
> ++   the stray byte is escaped to <BF> as 4 display columns.  */
> ++
> ++struct cpp_char_column_policy
> ++{
> ++  cpp_char_column_policy (int tabstop,
> ++                        int (*width_cb) (cppchar_t c))
> ++  : m_tabstop (tabstop),
> ++    m_undecoded_byte_width (1),
> ++    m_width_cb (width_cb)
> ++  {}
> ++
> ++  int m_tabstop;
> ++  /* Width in display columns of a stray byte that isn't decodable
> ++     as UTF-8.  */
> ++  int m_undecoded_byte_width;
> ++  int (*m_width_cb) (cppchar_t c);
> ++};
> ++
> + /* A class to manage the state while converting a UTF-8 sequence to
> cppchar_t
> +    and computing the display width one character at a time.  */
> + class cpp_display_width_computation {
> +  public:
> +   cpp_display_width_computation (const char *data, int data_length,
> +-                               int tabstop);
> ++                               const cpp_char_column_policy
> &policy);
> +   const char *next_byte () const { return m_next; }
> +   int bytes_processed () const { return m_next - m_begin; }
> +   int bytes_left () const { return m_bytes_left; }
> +   bool done () const { return !bytes_left (); }
> +   int display_cols_processed () const { return m_display_cols; }
> +
> +-  int process_next_codepoint ();
> ++  int process_next_codepoint (cpp_decoded_char *out);
> +   int advance_display_cols (int n);
> +
> +  private:
> +   const char *const m_begin;
> +   const char *m_next;
> +   size_t m_bytes_left;
> +-  const int m_tabstop;
> ++  const cpp_char_column_policy &m_policy;
> +   int m_display_cols;
> + };
> +
> + /* Convenience functions that are simple use cases for class
> +    cpp_display_width_computation.  Tab characters will be expanded
> to spaces
> +-   as determined by TABSTOP.  */
> ++   as determined by POLICY.m_tabstop, and non-printable-ASCII
> characters
> ++   will be escaped as per POLICY.  */
> ++
> + int cpp_byte_column_to_display_column (const char *data, int
> data_length,
> +-                                     int column, int tabstop);
> ++                                     int column,
> ++                                     const cpp_char_column_policy
> &policy);
> + inline int cpp_display_width (const char *data, int data_length,
> +-                            int tabstop)
> ++                            const cpp_char_column_policy &policy)
> + {
> +   return cpp_byte_column_to_display_column (data, data_length,
> data_length,
> +-                                          tabstop);
> ++                                          policy);
> + }
> + int cpp_display_column_to_byte_column (const char *data, int
> data_length,
> +-                                     int display_col, int tabstop);
> ++                                     int display_col,
> ++                                     const cpp_char_column_policy
> &policy);
> + int cpp_wcwidth (cppchar_t c);
> +
> + #endif /* ! LIBCPP_CPPLIB_H */
> +diff --git a/libcpp/include/line-map.h b/libcpp/include/line-map.h
> +--- a/libcpp/include/line-map.h        2020-07-22 23:35:18.712399623
> -0700
> ++++ b/libcpp/include/line-map.h        2021-12-25 01:30:50.685688757
> -0800
> +@@ -1732,6 +1732,18 @@ class rich_location
> +   const diagnostic_path *get_path () const { return m_path; }
> +   void set_path (const diagnostic_path *path) { m_path = path; }
> +
> ++  /* A flag for hinting that the diagnostic involves character
> encoding
> ++     issues, and thus that it will be helpful to the user if we
> show some
> ++     representation of how the characters in the pertinent source
> lines
> ++     are encoded.
> ++     The default is false (i.e. do not escape).
> ++     When set to true, non-ASCII bytes in the pertinent source
> lines will
> ++     be escaped in a manner controlled by the user-supplied option
> ++     -fdiagnostics-escape-format=, so that the user can better
> understand
> ++     what's going on with the encoding in their source file.  */
> ++  bool escape_on_output_p () const { return m_escape_on_output; }
> ++  void set_escape_on_output (bool flag) { m_escape_on_output =
> flag; }
> ++
> + private:
> +   bool reject_impossible_fixit (location_t where);
> +   void stop_supporting_fixits ();
> +@@ -1758,6 +1770,7 @@ protected:
> +   bool m_fixits_cannot_be_auto_applied;
> +
> +   const diagnostic_path *m_path;
> ++  bool m_escape_on_output;
> + };
> +
> + /* A struct for the result of range_label::get_text: a NUL-
> terminated buffer
> +diff --git a/libcpp/internal.h b/libcpp/internal.h
> +--- a/libcpp/internal.h        2020-07-22 23:35:18.712399623 -0700
> ++++ b/libcpp/internal.h        2021-12-25 01:30:50.685688757 -0800
> +@@ -758,6 +758,9 @@ struct _cpp_dir_only_callbacks
> + extern void _cpp_preprocess_dir_only (cpp_reader *,
> +                                     const struct
> _cpp_dir_only_callbacks *);
> +
> ++/* In errors.c  */
> ++extern location_t cpp_diagnostic_get_current_location (cpp_reader
> *);
> ++
> + /* In traditional.c.  */
> + extern bool _cpp_scan_out_logical_line (cpp_reader *, cpp_macro *,
> bool);
> + extern bool _cpp_read_logical_line_trad (cpp_reader *);
> +@@ -946,6 +949,26 @@ int linemap_get_expansion_line (class li
> + const char* linemap_get_expansion_filename (class line_maps *,
> +                                           location_t);
> +
> ++/* A subclass of rich_location for emitting a diagnostic
> ++   at the current location of the reader, but flagging
> ++   it with set_escape_on_output (true).  */
> ++class encoding_rich_location : public rich_location
> ++{
> ++ public:
> ++  encoding_rich_location (cpp_reader *pfile)
> ++  : rich_location (pfile->line_table,
> ++                 cpp_diagnostic_get_current_location (pfile))
> ++  {
> ++    set_escape_on_output (true);
> ++  }
> ++
> ++  encoding_rich_location (cpp_reader *pfile, location_t loc)
> ++  : rich_location (pfile->line_table, loc)
> ++  {
> ++    set_escape_on_output (true);
> ++  }
> ++};
> ++
> + #ifdef __cplusplus
> + }
> + #endif
> +diff --git a/libcpp/lex.c b/libcpp/lex.c
> +--- a/libcpp/lex.c     2021-12-24 20:23:45.568762024 -0800
> ++++ b/libcpp/lex.c     2021-12-25 01:30:50.685688757 -0800
> +@@ -1268,7 +1268,11 @@ skip_whitespace (cpp_reader *pfile, cppc
> +   while (is_nvspace (c));
> +
> +   if (saw_NUL)
> +-    cpp_error (pfile, CPP_DL_WARNING, "null character(s) ignored");
> ++    {
> ++      encoding_rich_location rich_loc (pfile);
> ++      cpp_error_at (pfile, CPP_DL_WARNING, &rich_loc,
> ++                  "null character(s) ignored");
> ++    }
> +
> +   buffer->cur--;
> + }
> +@@ -1297,6 +1301,28 @@ warn_about_normalization (cpp_reader *pf
> +   if (CPP_OPTION (pfile, warn_normalize) < NORMALIZE_STATE_RESULT
> (s)
> +       && !pfile->state.skipping)
> +     {
> ++      location_t loc = token->src_loc;
> ++
> ++      /* If possible, create a location range for the token.  */
> ++      if (loc >= RESERVED_LOCATION_COUNT
> ++        && token->type != CPP_EOF
> ++        /* There must be no line notes to process.  */
> ++        && (!(pfile->buffer->cur
> ++              >= pfile->buffer->notes[pfile->buffer->cur_note].pos
> ++              && !pfile->overlaid_buffer)))
> ++      {
> ++        source_range tok_range;
> ++        tok_range.m_start = loc;
> ++        tok_range.m_finish
> ++          = linemap_position_for_column (pfile->line_table,
> ++                                         CPP_BUF_COLUMN (pfile-
> >buffer,
> ++                                                         pfile-
> >buffer->cur));
> ++        loc = COMBINE_LOCATION_DATA (pfile->line_table,
> ++                                     loc, tok_range, NULL);
> ++      }
> ++
> ++      encoding_rich_location rich_loc (pfile, loc);
> ++
> +       /* Make sure that the token is printed using UCNs, even
> +        if we'd otherwise happily print UTF-8.  */
> +       unsigned char *buf = XNEWVEC (unsigned char, cpp_token_len
> (token));
> +@@ -1304,11 +1330,11 @@ warn_about_normalization (cpp_reader *pf
> +
> +       sz = cpp_spell_token (pfile, token, buf, false) - buf;
> +       if (NORMALIZE_STATE_RESULT (s) == normalized_C)
> +-      cpp_warning_with_line (pfile, CPP_W_NORMALIZE, token-
> >src_loc, 0,
> +-                             "`%.*s' is not in NFKC", (int) sz,
> buf);
> ++      cpp_warning_at (pfile, CPP_W_NORMALIZE, &rich_loc,
> ++                      "`%.*s' is not in NFKC", (int) sz, buf);
> +       else
> +-      cpp_warning_with_line (pfile, CPP_W_NORMALIZE, token-
> >src_loc, 0,
> +-                             "`%.*s' is not in NFC", (int) sz,
> buf);
> ++      cpp_warning_at (pfile, CPP_W_NORMALIZE, &rich_loc,
> ++                      "`%.*s' is not in NFC", (int) sz, buf);
> +       free (buf);
> +     }
> + }
> +diff --git a/libcpp/line-map.c b/libcpp/line-map.c
> +--- a/libcpp/line-map.c        2020-07-22 23:35:18.712399623 -0700
> ++++ b/libcpp/line-map.c        2021-12-25 01:30:50.685688757 -0800
> +@@ -2007,7 +2007,8 @@ rich_location::rich_location (line_maps
> +   m_fixit_hints (),
> +   m_seen_impossible_fixit (false),
> +   m_fixits_cannot_be_auto_applied (false),
> +-  m_path (NULL)
> ++  m_path (NULL),
> ++  m_escape_on_output (false)
> + {
> +   add_range (loc, SHOW_RANGE_WITH_CARET, label);
> + }
> diff --git a/meta/recipes-devtools/gcc/gcc/0003-CVE-2021-42574.patch
> b/meta/recipes-devtools/gcc/gcc/0003-CVE-2021-42574.patch
> new file mode 100644
> index 0000000000..6bfaf8402d
> --- /dev/null
> +++ b/meta/recipes-devtools/gcc/gcc/0003-CVE-2021-42574.patch
> @@ -0,0 +1,1724 @@
> +From 51c500269bf53749b107807d84271385fad35628 Mon Sep 17 00:00:00
> 2001
> +From: Marek Polacek <polacek@redhat.com>
> +Date: Wed, 6 Oct 2021 14:33:59 -0400
> +Subject: [PATCH] libcpp: Implement -Wbidi-chars for CVE-2021-42574
> [PR103026]
> +
> +From a link below:
> +"An issue was discovered in the Bidirectional Algorithm in the
> Unicode
> +Specification through 14.0. It permits the visual reordering of
> +characters via control sequences, which can be used to craft source
> code
> +that renders different logic than the logical ordering of tokens
> +ingested by compilers and interpreters. Adversaries can leverage
> this to
> +encode source code for compilers accepting Unicode such that
> targeted
> +vulnerabilities are introduced invisibly to human reviewers."
> +
> +More info:
> +https://nvd.nist.gov/vuln/detail/CVE-2021-42574
> +https://trojansource.codes/
> +
> +This is not a compiler bug.  However, to mitigate the problem, this
> patch
> +implements -Wbidi-chars=[none|unpaired|any] to warn about possibly
> +misleading Unicode bidirectional control characters the preprocessor
> may
> +encounter.
> +
> +The default is =unpaired, which warns about improperly terminated
> +bidirectional control characters; e.g. a LRE without its
> corresponding PDF.
> +The level =any warns about any use of bidirectional control
> characters.
> +
> +This patch handles both UCNs and UTF-8 characters.  UCNs designating
> +bidi characters in identifiers are accepted since r204886.  Then
> r217144
> +enabled -fextended-identifiers by default.  Extended characters in
> C/C++
> +identifiers have been accepted since r275979.  However, this patch
> still
> +warns about mixing UTF-8 and UCN bidi characters; there seems to be
> no
> +good reason to allow mixing them.
> +
> +We warn in different contexts: comments (both C and C++-style),
> string
> +literals, character constants, and identifiers.  Expectedly, UCNs
> are ignored
> +in comments and raw string literals.  The bidirectional control
> characters
> +can nest so this patch handles that as well.
> +
> +I have not included nor tested this at all with Fortran (which also
> has
> +string literals and line comments).
> +
> +Dave M. posted patches improving diagnostic involving Unicode
> characters.
> +This patch does not make use of this new infrastructure yet.
> +
> +       PR preprocessor/103026
> +
> +gcc/c-family/ChangeLog:
> +
> +       * c.opt (Wbidi-chars, Wbidi-chars=): New option.
> +
> +gcc/ChangeLog:
> +
> +       * doc/invoke.texi: Document -Wbidi-chars.
> +
> +libcpp/ChangeLog:
> +
> +       * include/cpplib.h (enum cpp_bidirectional_level): New.
> +       (struct cpp_options): Add cpp_warn_bidirectional.
> +       (enum cpp_warning_reason): Add CPP_W_BIDIRECTIONAL.
> +       * internal.h (struct cpp_reader): Add warn_bidi_p member
> +       function.
> +       * init.c (cpp_create_reader): Set cpp_warn_bidirectional.
> +       * lex.c (bidi): New namespace.
> +       (get_bidi_utf8): New function.
> +       (get_bidi_ucn): Likewise.
> +       (maybe_warn_bidi_on_close): Likewise.
> +       (maybe_warn_bidi_on_char): Likewise.
> +       (_cpp_skip_block_comment): Implement warning about
> bidirectional
> +       control characters.
> +       (skip_line_comment): Likewise.
> +       (forms_identifier_p): Likewise.
> +       (lex_identifier): Likewise.
> +       (lex_string): Likewise.
> +       (lex_raw_string): Likewise.
> +
> +gcc/testsuite/ChangeLog:
> +
> +       * c-c++-common/Wbidi-chars-1.c: New test.
> +       * c-c++-common/Wbidi-chars-2.c: New test.
> +       * c-c++-common/Wbidi-chars-3.c: New test.
> +       * c-c++-common/Wbidi-chars-4.c: New test.
> +       * c-c++-common/Wbidi-chars-5.c: New test.
> +       * c-c++-common/Wbidi-chars-6.c: New test.
> +       * c-c++-common/Wbidi-chars-7.c: New test.
> +       * c-c++-common/Wbidi-chars-8.c: New test.
> +       * c-c++-common/Wbidi-chars-9.c: New test.
> +       * c-c++-common/Wbidi-chars-10.c: New test.
> +       * c-c++-common/Wbidi-chars-11.c: New test.
> +       * c-c++-common/Wbidi-chars-12.c: New test.
> +       * c-c++-common/Wbidi-chars-13.c: New test.
> +       * c-c++-common/Wbidi-chars-14.c: New test.
> +       * c-c++-common/Wbidi-chars-15.c: New test.
> +       * c-c++-common/Wbidi-chars-16.c: New test.
> +       * c-c++-common/Wbidi-chars-17.c: New test.
> +
> +CVE: CVE-2021-42574
> +Upstream-Status: Backport
> [https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=51c500269bf53749b1078
> 07d84271385fad35628]
> +Signed-off-by: Pgowda <pgowda.cve@gmail.com>
> +
> +---
> + gcc/c-family/c.opt                          |  24 ++
> + gcc/doc/invoke.texi                         |  21 +-
> + gcc/testsuite/c-c++-common/Wbidi-chars-1.c  |  12 +
> + gcc/testsuite/c-c++-common/Wbidi-chars-10.c |  27 ++
> + gcc/testsuite/c-c++-common/Wbidi-chars-11.c |  13 +
> + gcc/testsuite/c-c++-common/Wbidi-chars-12.c |  19 +
> + gcc/testsuite/c-c++-common/Wbidi-chars-13.c |  17 +
> + gcc/testsuite/c-c++-common/Wbidi-chars-14.c |  38 ++
> + gcc/testsuite/c-c++-common/Wbidi-chars-15.c |  59 +++
> + gcc/testsuite/c-c++-common/Wbidi-chars-16.c |  26 ++
> + gcc/testsuite/c-c++-common/Wbidi-chars-17.c |  30 ++
> + gcc/testsuite/c-c++-common/Wbidi-chars-2.c  |   9 +
> + gcc/testsuite/c-c++-common/Wbidi-chars-3.c  |  11 +
> + gcc/testsuite/c-c++-common/Wbidi-chars-4.c  | 188 +++++++++
> + gcc/testsuite/c-c++-common/Wbidi-chars-5.c  | 188 +++++++++
> + gcc/testsuite/c-c++-common/Wbidi-chars-6.c  | 155 ++++++++
> + gcc/testsuite/c-c++-common/Wbidi-chars-7.c  |   9 +
> + gcc/testsuite/c-c++-common/Wbidi-chars-8.c  |  13 +
> + gcc/testsuite/c-c++-common/Wbidi-chars-9.c  |  29 ++
> + libcpp/include/cpplib.h                     |  18 +-
> + libcpp/init.c                               |   1 +
> + libcpp/internal.h                           |   7 +
> + libcpp/lex.c                                | 408
> +++++++++++++++++++-
> + 23 files changed, 1315 insertions(+), 7 deletions(-)
> + create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-1.c
> + create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-10.c
> + create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-11.c
> + create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-12.c
> + create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-13.c
> + create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-14.c
> + create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-15.c
> + create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-16.c
> + create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-17.c
> + create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-2.c
> + create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-3.c
> + create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-4.c
> + create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-5.c
> + create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-6.c
> + create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-7.c
> + create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-8.c
> + create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-9.c
> +
> +diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
> +--- a/gcc/c-family/c.opt       2021-12-25 01:29:12.915317374 -0800
> ++++ b/gcc/c-family/c.opt       2021-12-25 01:36:22.040018701 -0800
> +@@ -350,6 +350,30 @@ Wbad-function-cast
> + C ObjC Var(warn_bad_function_cast) Warning
> + Warn about casting functions to incompatible types.
> +
> ++Wbidi-chars
> ++C ObjC C++ ObjC++ Warning Alias(Wbidi-chars=,any,none)
> ++;
> ++
> ++Wbidi-chars=
> ++C ObjC C++ ObjC++ RejectNegative Joined Warning
> CPP(cpp_warn_bidirectional) CppReason(CPP_W_BIDIRECTIONAL)
> Var(warn_bidirectional) Init(bidirectional_unpaired)
> Enum(cpp_bidirectional_level)
> ++-Wbidi-chars=[none|unpaired|any] Warn about UTF-8 bidirectional
> control characters.
> ++
> ++; Required for these enum values.
> ++SourceInclude
> ++cpplib.h
> ++
> ++Enum
> ++Name(cpp_bidirectional_level) Type(int) UnknownError(argument %qs
> to %<-Wbidi-chars%> not recognized)
> ++
> ++EnumValue
> ++Enum(cpp_bidirectional_level) String(none)
> Value(bidirectional_none)
> ++
> ++EnumValue
> ++Enum(cpp_bidirectional_level) String(unpaired)
> Value(bidirectional_unpaired)
> ++
> ++EnumValue
> ++Enum(cpp_bidirectional_level) String(any) Value(bidirectional_any)
> ++
> + Wbool-compare
> + C ObjC C++ ObjC++ Var(warn_bool_compare) Warning LangEnabledBy(C
> ObjC C++ ObjC++,Wall)
> + Warn about boolean expression compared with an integer value
> different from true/false.
> +diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> +--- a/gcc/doc/invoke.texi      2021-12-25 01:35:33.284883488 -0800
> ++++ b/gcc/doc/invoke.texi      2021-12-25 01:36:22.048018559 -0800
> +@@ -310,7 +310,9 @@ Objective-C and Objective-C++ Dialects}.
> + -Warith-conversion @gol
> + -Warray-bounds  -Warray-bounds=@var{n} @gol
> + -Wno-attributes  -Wattribute-alias=@var{n} -Wno-attribute-alias
> @gol
> +--Wno-attribute-warning  -Wbool-compare  -Wbool-operation @gol
> ++-Wno-attribute-warning  @gol
> ++-Wbidi-chars=@r{[}none@r{|}unpaired@r{|}any@r{]} @gol
> ++-Wbool-compare  -Wbool-operation @gol
> + -Wno-builtin-declaration-mismatch @gol
> + -Wno-builtin-macro-redefined  -Wc90-c99-compat  -Wc99-c11-compat
> @gol
> + -Wc11-c2x-compat @gol
> +@@ -6860,6 +6862,23 @@ Attributes considered include @code{allo
> + This is the default.  You can disable these warnings with either
> + @option{-Wno-attribute-alias} or @option{-Wattribute-alias=0}.
> +
> ++@item -Wbidi-chars=@r{[}none@r{|}unpaired@r{|}any@r{]}
> ++@opindex Wbidi-chars=
> ++@opindex Wbidi-chars
> ++@opindex Wno-bidi-chars
> ++Warn about possibly misleading UTF-8 bidirectional control
> characters in
> ++comments, string literals, character constants, and identifiers.
> Such
> ++characters can change left-to-right writing direction into right-
> to-left
> ++(and vice versa), which can cause confusion between the logical
> order and
> ++visual order.  This may be dangerous; for instance, it may seem
> that a piece
> ++of code is not commented out, whereas it in fact is.
> ++
> ++There are three levels of warning supported by GCC@.  The default
> is
> ++@option{-Wbidi-chars=unpaired}, which warns about improperly
> terminated
> ++bidi contexts.  @option{-Wbidi-chars=none} turns the warning off.
> ++@option{-Wbidi-chars=any} warns about any use of bidirectional
> control
> ++characters.
> ++
> + @item -Wbool-compare
> + @opindex Wno-bool-compare
> + @opindex Wbool-compare
> +diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-10.c
> b/gcc/testsuite/c-c++-common/Wbidi-chars-10.c
> +--- a/gcc/testsuite/c-c++-common/Wbidi-chars-10.c      1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-10.c      2021-12-25
> 01:36:22.048018559 -0800
> +@@ -0,0 +1,27 @@
> ++/* PR preprocessor/103026 */
> ++/* { dg-do compile } */
> ++/* { dg-options "-Wbidi-chars=unpaired" } */
> ++/* More nesting testing.  */
> ++
> ++/* RLE‫ LRI⁦ PDF‬ PDI⁩*/
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int LRE_\u202a_PDF_\u202c;
> ++int LRE_\u202a_PDF_\u202c_LRE_\u202a_PDF_\u202c;
> ++int LRE_\u202a_LRI_\u2066_PDF_\u202c_PDI_\u2069;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int RLE_\u202b_RLI_\u2067_PDF_\u202c_PDI_\u2069;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int RLE_\u202b_RLI_\u2067_PDI_\u2069_PDF_\u202c;
> ++int FSI_\u2068_LRO_\u202d_PDI_\u2069_PDF_\u202c;
> ++int FSI_\u2068;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int FSI_\u2068_PDI_\u2069;
> ++int FSI_\u2068_FSI_\u2068_PDI_\u2069;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int
> RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI
> _\u2067_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u
> 2069_PDI_\u2069;
> ++int
> RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI
> _\u2067_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u
> 2069;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int
> RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI
> _\u2067_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u2069_PDI_\u
> 2069_PDF_\u202c;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int
> RLI_\u2067_RLI_\u2067_RLI_\u2067_RLI_\u2067_FSI_\u2068_PDI_\u2069_PDI
> _\u2069_PDI_\u2069_PDI_\u2069;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> +diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-11.c
> b/gcc/testsuite/c-c++-common/Wbidi-chars-11.c
> +--- a/gcc/testsuite/c-c++-common/Wbidi-chars-11.c      1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-11.c      2021-12-25
> 01:36:22.048018559 -0800
> +@@ -0,0 +1,13 @@
> ++/* PR preprocessor/103026 */
> ++/* { dg-do compile } */
> ++/* { dg-options "-Wbidi-chars=unpaired" } */
> ++/* Test that we warn when mixing UCN and UTF-8.  */
> ++
> ++int LRE_‪_PDF_\u202c;
> ++/* { dg-warning "mismatch" "" { target *-*-* } .-1 } */
> ++int LRE_\u202a_PDF_‬_;
> ++/* { dg-warning "mismatch" "" { target *-*-* } .-1 } */
> ++const char *s1 = "LRE_‪_PDF_\u202c";
> ++/* { dg-warning "mismatch" "" { target *-*-* } .-1 } */
> ++const char *s2 = "LRE_\u202a_PDF_‬";
> ++/* { dg-warning "mismatch" "" { target *-*-* } .-1 } */
> +diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-12.c
> b/gcc/testsuite/c-c++-common/Wbidi-chars-12.c
> +--- a/gcc/testsuite/c-c++-common/Wbidi-chars-12.c      1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-12.c      2021-12-25
> 01:36:22.048018559 -0800
> +@@ -0,0 +1,19 @@
> ++/* PR preprocessor/103026 */
> ++/* { dg-do compile { target { c || c++11 } } } */
> ++/* { dg-options "-Wbidi-chars=any" } */
> ++/* Test raw strings.  */
> ++
> ++const char *s1 = R"(a b c LRE‪ 1 2 3 PDF‬ x y z)";
> ++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
> ++const char *s2 = R"(a b c RLE‫ 1 2 3 PDF‬ x y z)";
> ++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
> ++const char *s3 = R"(a b c LRO‭ 1 2 3 PDF‬ x y z)";
> ++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
> ++const char *s4 = R"(a b c RLO‮ 1 2 3 PDF‬ x y z)";
> ++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
> ++const char *s7 = R"(a b c FSI⁨ 1 2 3 PDI⁩ x y) z";
> ++/* { dg-warning "U\\+2068" "" { target *-*-* } .-1 } */
> ++const char *s8 = R"(a b c PDI⁩ x y )z";
> ++/* { dg-warning "U\\+2069" "" { target *-*-* } .-1 } */
> ++const char *s9 = R"(a b c PDF‬ x y z)";
> ++/* { dg-warning "U\\+202C" "" { target *-*-* } .-1 } */
> +diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-13.c
> b/gcc/testsuite/c-c++-common/Wbidi-chars-13.c
> +--- a/gcc/testsuite/c-c++-common/Wbidi-chars-13.c      1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-13.c      2021-12-25
> 01:36:22.048018559 -0800
> +@@ -0,0 +1,17 @@
> ++/* PR preprocessor/103026 */
> ++/* { dg-do compile { target { c || c++11 } } } */
> ++/* { dg-options "-Wbidi-chars=unpaired" } */
> ++/* Test raw strings.  */
> ++
> ++const char *s1 = R"(a b c LRE‪ 1 2 3)";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++const char *s2 = R"(a b c RLE‫ 1 2 3)";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++const char *s3 = R"(a b c LRO‭ 1 2 3)";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++const char *s4 = R"(a b c FSI⁨ 1 2 3)";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++const char *s5 = R"(a b c LRI⁦ 1 2 3)";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++const char *s6 = R"(a b c RLI⁧ 1 2 3)";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> +diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-14.c
> b/gcc/testsuite/c-c++-common/Wbidi-chars-14.c
> +--- a/gcc/testsuite/c-c++-common/Wbidi-chars-14.c      1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-14.c      2021-12-25
> 01:36:22.048018559 -0800
> +@@ -0,0 +1,38 @@
> ++/* PR preprocessor/103026 */
> ++/* { dg-do compile } */
> ++/* { dg-options "-Wbidi-chars=unpaired" } */
> ++/* Test PDI handling, which also pops any subsequent LREs, RLEs,
> LROs,
> ++   or RLOs.  */
> ++
> ++/* LRI_⁦_LRI_⁦_RLE_‫_RLE_‫_RLE_‫_PDI_⁩*/
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++// LRI_⁦_RLE_‫_RLE_‫_RLE_‫_PDI_⁩
> ++// LRI_⁦_RLO_‮_RLE_‫_RLE_‫_PDI_⁩
> ++// LRI_⁦_RLO_‮_RLE_‫_PDI_⁩
> ++// FSI_⁨_RLO_‮_PDI_⁩
> ++// FSI_⁨_FSI_⁨_RLO_‮_PDI_⁩
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++
> ++int
> LRI_\u2066_LRI_\u2066_LRE_\u202a_LRE_\u202a_LRE_\u202a_PDI_\u2069;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int
> LRI_\u2066_LRI_\u2066_LRE_\u202a_LRE_\u202a_LRE_\u202a_PDI_\u2069_PDI
> _\u2069;
> ++int
> LRI_\u2066_LRI_\u2066_LRI_\u2066_LRE_\u202a_LRE_\u202a_LRE_\u202a_PDI
> _\u2069_PDI_\u2069;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int PDI_\u2069;
> ++int LRI_\u2066_PDI_\u2069;
> ++int RLI_\u2067_PDI_\u2069;
> ++int LRE_\u202a_LRI_\u2066_PDI_\u2069;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int LRI_\u2066_LRE_\u202a_PDF_\u202c_PDI_\u2069;
> ++int LRI_\u2066_LRE_\u202a_LRE_\u202a_PDF_\u202c_PDI_\u2069;
> ++int
> RLI_\u2067_LRI_\u2066_LRE_\u202a_LRE_\u202a_PDF_\u202c_PDI_\u2069;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int
> FSI_\u2068_LRI_\u2066_LRE_\u202a_LRE_\u202a_PDF_\u202c_PDI_\u2069;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int RLO_\u202e_PDI_\u2069;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int RLI_\u2067_PDI_\u2069_RLI_\u2067;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int FSI_\u2068_PDF_\u202c_PDI_\u2069;
> ++int FSI_\u2068_FSI_\u2068_PDF_\u202c_PDI_\u2069;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> +diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-15.c
> b/gcc/testsuite/c-c++-common/Wbidi-chars-15.c
> +--- a/gcc/testsuite/c-c++-common/Wbidi-chars-15.c      1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-15.c      2021-12-25
> 01:36:22.048018559 -0800
> +@@ -0,0 +1,59 @@
> ++/* PR preprocessor/103026 */
> ++/* { dg-do compile } */
> ++/* { dg-options "-Wbidi-chars=unpaired" } */
> ++/* Test unpaired bidi control chars in multiline comments.  */
> ++
> ++/*
> ++ * LRE‪ end
> ++ */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
> ++/*
> ++ * RLE‫ end
> ++ */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
> ++/*
> ++ * LRO‭ end
> ++ */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
> ++/*
> ++ * RLO‮ end
> ++ */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
> ++/*
> ++ * LRI⁦ end
> ++ */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
> ++/*
> ++ * RLI⁧ end
> ++ */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
> ++/*
> ++ * FSI⁨ end
> ++ */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
> ++/* LRE‪
> ++   PDF‬ */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
> ++/* FSI⁨
> ++   PDI⁩ */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
> ++
> ++/* LRE<‪>
> ++ *
> ++ */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-3 } */
> ++
> ++/*
> ++ * LRE<‪>
> ++ */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
> ++
> ++/*
> ++ *
> ++ * LRE<‪> */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++
> ++/* RLI<⁧> */ /* PDI<⁩> */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++/* LRE<‪> */ /* PDF<‬> */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> +diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-16.c
> b/gcc/testsuite/c-c++-common/Wbidi-chars-16.c
> +--- a/gcc/testsuite/c-c++-common/Wbidi-chars-16.c      1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-16.c      2021-12-25
> 01:36:22.048018559 -0800
> +@@ -0,0 +1,26 @@
> ++/* PR preprocessor/103026 */
> ++/* { dg-do compile } */
> ++/* { dg-options "-Wbidi-chars=any" } */
> ++/* Test LTR/RTL chars.  */
> ++
> ++/* LTR<‎> */
> ++/* { dg-warning "U\\+200E" "" { target *-*-* } .-1 } */
> ++// LTR<‎>
> ++/* { dg-warning "U\\+200E" "" { target *-*-* } .-1 } */
> ++/* RTL<‏> */
> ++/* { dg-warning "U\\+200F" "" { target *-*-* } .-1 } */
> ++// RTL<‏>
> ++/* { dg-warning "U\\+200F" "" { target *-*-* } .-1 } */
> ++
> ++const char *s1 = "LTR<‎>";
> ++/* { dg-warning "U\\+200E" "" { target *-*-* } .-1 } */
> ++const char *s2 = "LTR\u200e";
> ++/* { dg-warning "U\\+200E" "" { target *-*-* } .-1 } */
> ++const char *s3 = "LTR\u200E";
> ++/* { dg-warning "U\\+200E" "" { target *-*-* } .-1 } */
> ++const char *s4 = "RTL<‏>";
> ++/* { dg-warning "U\\+200F" "" { target *-*-* } .-1 } */
> ++const char *s5 = "RTL\u200f";
> ++/* { dg-warning "U\\+200F" "" { target *-*-* } .-1 } */
> ++const char *s6 = "RTL\u200F";
> ++/* { dg-warning "U\\+200F" "" { target *-*-* } .-1 } */
> +diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-17.c
> b/gcc/testsuite/c-c++-common/Wbidi-chars-17.c
> +--- a/gcc/testsuite/c-c++-common/Wbidi-chars-17.c      1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-17.c      2021-12-25
> 01:36:22.048018559 -0800
> +@@ -0,0 +1,30 @@
> ++/* PR preprocessor/103026 */
> ++/* { dg-do compile } */
> ++/* { dg-options "-Wbidi-chars=unpaired" } */
> ++/* Test LTR/RTL chars.  */
> ++
> ++/* LTR<‎> */
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++// LTR<‎>
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++/* RTL<‏> */
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++// RTL<‏>
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int ltr_\u200e;
> ++/* { dg-error "universal character " "" { target *-*-* } .-1 } */
> ++int rtl_\u200f;
> ++/* { dg-error "universal character " "" { target *-*-* } .-1 } */
> ++
> ++const char *s1 = "LTR<‎>";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++const char *s2 = "LTR\u200e";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++const char *s3 = "LTR\u200E";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++const char *s4 = "RTL<‏>";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++const char *s5 = "RTL\u200f";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++const char *s6 = "RTL\u200F";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> +diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-1.c
> b/gcc/testsuite/c-c++-common/Wbidi-chars-1.c
> +--- a/gcc/testsuite/c-c++-common/Wbidi-chars-1.c       1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-1.c       2021-12-25
> 01:36:22.048018559 -0800
> +@@ -0,0 +1,12 @@
> ++/* PR preprocessor/103026 */
> ++/* { dg-do compile } */
> ++
> ++int main() {
> ++    int isAdmin = 0;
> ++    /*‮ } ⁦if (isAdmin)⁩ ⁦ begin admins only */
> ++/* { dg-warning "bidirectional" "" { target *-*-* } .-1 } */
> ++        __builtin_printf("You are an admin.\n");
> ++    /* end admins only ‮ { ⁦*/
> ++/* { dg-warning "bidirectional" "" { target *-*-* } .-1 } */
> ++    return 0;
> ++}
> +diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-2.c
> b/gcc/testsuite/c-c++-common/Wbidi-chars-2.c
> +--- a/gcc/testsuite/c-c++-common/Wbidi-chars-2.c       1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-2.c       2021-12-25
> 01:36:22.048018559 -0800
> +@@ -0,0 +1,9 @@
> ++/* PR preprocessor/103026 */
> ++/* { dg-do compile } */
> ++
> ++int main() {
> ++    /* Say hello; newline⁧/*/ return 0 ;
> ++/* { dg-warning "bidirectional" "" { target *-*-* } .-1 } */
> ++    __builtin_printf("Hello world.\n");
> ++    return 0;
> ++}
> +diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-3.c
> b/gcc/testsuite/c-c++-common/Wbidi-chars-3.c
> +--- a/gcc/testsuite/c-c++-common/Wbidi-chars-3.c       1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-3.c       2021-12-25
> 01:36:22.048018559 -0800
> +@@ -0,0 +1,11 @@
> ++/* PR preprocessor/103026 */
> ++/* { dg-do compile } */
> ++
> ++int main() {
> ++    const char* access_level = "user";
> ++    if (__builtin_strcmp(access_level, "user‮ ⁦// Check if admin⁩
> ⁦")) {
> ++/* { dg-warning "bidirectional" "" { target *-*-* } .-1 } */
> ++        __builtin_printf("You are an admin.\n");
> ++    }
> ++    return 0;
> ++}
> +diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-4.c
> b/gcc/testsuite/c-c++-common/Wbidi-chars-4.c
> +--- a/gcc/testsuite/c-c++-common/Wbidi-chars-4.c       1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-4.c       2021-12-25
> 01:36:22.048018559 -0800
> +@@ -0,0 +1,188 @@
> ++/* PR preprocessor/103026 */
> ++/* { dg-do compile } */
> ++/* { dg-options "-Wbidi-chars=any -Wno-multichar -Wno-overflow" }
> */
> ++/* Test all bidi chars in various contexts (identifiers, comments,
> ++   string literals, character constants), both UCN and UTF-8.  The
> bidi
> ++   chars here are properly terminated, except for the character
> constants.  */
> ++
> ++/* a b c LRE‪ 1 2 3 PDF‬ x y z */
> ++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
> ++/* a b c RLE‫ 1 2 3 PDF‬ x y z */
> ++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
> ++/* a b c LRO‭ 1 2 3 PDF‬ x y z */
> ++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
> ++/* a b c RLO‮ 1 2 3 PDF‬ x y z */
> ++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
> ++/* a b c LRI⁦ 1 2 3 PDI⁩ x y z */
> ++/* { dg-warning "U\\+2066" "" { target *-*-* } .-1 } */
> ++/* a b c RLI⁧ 1 2 3 PDI⁩ x y */
> ++/* { dg-warning "U\\+2067" "" { target *-*-* } .-1 } */
> ++/* a b c FSI⁨ 1 2 3 PDI⁩ x y z */
> ++/* { dg-warning "U\\+2068" "" { target *-*-* } .-1 } */
> ++
> ++/* Same but C++ comments instead.  */
> ++// a b c LRE‪ 1 2 3 PDF‬ x y z
> ++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
> ++// a b c RLE‫ 1 2 3 PDF‬ x y z
> ++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
> ++// a b c LRO‭ 1 2 3 PDF‬ x y z
> ++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
> ++// a b c RLO‮ 1 2 3 PDF‬ x y z
> ++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
> ++// a b c LRI⁦ 1 2 3 PDI⁩ x y z
> ++/* { dg-warning "U\\+2066" "" { target *-*-* } .-1 } */
> ++// a b c RLI⁧ 1 2 3 PDI⁩ x y
> ++/* { dg-warning "U\\+2067" "" { target *-*-* } .-1 } */
> ++// a b c FSI⁨ 1 2 3 PDI⁩ x y z
> ++/* { dg-warning "U\\+2068" "" { target *-*-* } .-1 } */
> ++
> ++/* Here we're closing an unopened context, warn when =any.  */
> ++/* a b c PDI⁩ x y z */
> ++/* { dg-warning "U\\+2069" "" { target *-*-* } .-1 } */
> ++/* a b c PDF‬ x y z */
> ++/* { dg-warning "U\\+202C" "" { target *-*-* } .-1 } */
> ++// a b c PDI⁩ x y z
> ++/* { dg-warning "U\\+2069" "" { target *-*-* } .-1 } */
> ++// a b c PDF‬ x y z
> ++/* { dg-warning "U\\+202C" "" { target *-*-* } .-1 } */
> ++
> ++/* Multiline comments.  */
> ++/* a b c PDI⁩ x y z
> ++   */
> ++/* { dg-warning "U\\+2069" "" { target *-*-* } .-2 } */
> ++/* a b c PDF‬ x y z
> ++   */
> ++/* { dg-warning "U\\+202C" "" { target *-*-* } .-2 } */
> ++/* first
> ++   a b c PDI⁩ x y z
> ++   */
> ++/* { dg-warning "U\\+2069" "" { target *-*-* } .-2 } */
> ++/* first
> ++   a b c PDF‬ x y z
> ++   */
> ++/* { dg-warning "U\\+202C" "" { target *-*-* } .-2 } */
> ++/* first
> ++   a b c PDI⁩ x y z */
> ++/* { dg-warning "U\\+2069" "" { target *-*-* } .-1 } */
> ++/* first
> ++   a b c PDF‬ x y z */
> ++/* { dg-warning "U\\+202C" "" { target *-*-* } .-1 } */
> ++
> ++void
> ++g1 ()
> ++{
> ++  const char *s1 = "a b c LRE‪ 1 2 3 PDF‬ x y z";
> ++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
> ++  const char *s2 = "a b c RLE‫ 1 2 3 PDF‬ x y z";
> ++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
> ++  const char *s3 = "a b c LRO‭ 1 2 3 PDF‬ x y z";
> ++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
> ++  const char *s4 = "a b c RLO‮ 1 2 3 PDF‬ x y z";
> ++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
> ++  const char *s5 = "a b c LRI⁦ 1 2 3 PDI⁩ x y z";
> ++/* { dg-warning "U\\+2066" "" { target *-*-* } .-1 } */
> ++  const char *s6 = "a b c RLI⁧ 1 2 3 PDI⁩ x y z";
> ++/* { dg-warning "U\\+2067" "" { target *-*-* } .-1 } */
> ++  const char *s7 = "a b c FSI⁨ 1 2 3 PDI⁩ x y z";
> ++/* { dg-warning "U\\+2068" "" { target *-*-* } .-1 } */
> ++  const char *s8 = "a b c PDI⁩ x y z";
> ++/* { dg-warning "U\\+2069" "" { target *-*-* } .-1 } */
> ++  const char *s9 = "a b c PDF‬ x y z";
> ++/* { dg-warning "U\\+202C" "" { target *-*-* } .-1 } */
> ++
> ++  const char *s10 = "a b c LRE\u202a 1 2 3 PDF\u202c x y z";
> ++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
> ++  const char *s11 = "a b c LRE\u202A 1 2 3 PDF\u202c x y z";
> ++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
> ++  const char *s12 = "a b c RLE\u202b 1 2 3 PDF\u202c x y z";
> ++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
> ++  const char *s13 = "a b c RLE\u202B 1 2 3 PDF\u202c x y z";
> ++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
> ++  const char *s14 = "a b c LRO\u202d 1 2 3 PDF\u202c x y z";
> ++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
> ++  const char *s15 = "a b c LRO\u202D 1 2 3 PDF\u202c x y z";
> ++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
> ++  const char *s16 = "a b c RLO\u202e 1 2 3 PDF\u202c x y z";
> ++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
> ++  const char *s17 = "a b c RLO\u202E 1 2 3 PDF\u202c x y z";
> ++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
> ++  const char *s18 = "a b c LRI\u2066 1 2 3 PDI\u2069 x y z";
> ++/* { dg-warning "U\\+2066" "" { target *-*-* } .-1 } */
> ++  const char *s19 = "a b c RLI\u2067 1 2 3 PDI\u2069 x y z";
> ++/* { dg-warning "U\\+2067" "" { target *-*-* } .-1 } */
> ++  const char *s20 = "a b c FSI\u2068 1 2 3 PDI\u2069 x y z";
> ++/* { dg-warning "U\\+2068" "" { target *-*-* } .-1 } */
> ++}
> ++
> ++void
> ++g2 ()
> ++{
> ++  const char c1 = '\u202a';
> ++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
> ++  const char c2 = '\u202A';
> ++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
> ++  const char c3 = '\u202b';
> ++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
> ++  const char c4 = '\u202B';
> ++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
> ++  const char c5 = '\u202d';
> ++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
> ++  const char c6 = '\u202D';
> ++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
> ++  const char c7 = '\u202e';
> ++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
> ++  const char c8 = '\u202E';
> ++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
> ++  const char c9 = '\u2066';
> ++/* { dg-warning "U\\+2066" "" { target *-*-* } .-1 } */
> ++  const char c10 = '\u2067';
> ++/* { dg-warning "U\\+2067" "" { target *-*-* } .-1 } */
> ++  const char c11 = '\u2068';
> ++/* { dg-warning "U\\+2068" "" { target *-*-* } .-1 } */
> ++}
> ++
> ++int a‪b‬c;
> ++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
> ++int a‫b‬c;
> ++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
> ++int a‭b‬c;
> ++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
> ++int a‮b‬c;
> ++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
> ++int a⁦b⁩c;
> ++/* { dg-warning "U\\+2066" "" { target *-*-* } .-1 } */
> ++int a⁧b⁩c;
> ++/* { dg-warning "U\\+2067" "" { target *-*-* } .-1 } */
> ++int a⁨b⁩c;
> ++/* { dg-warning "U\\+2068" "" { target *-*-* } .-1 } */
> ++int A‬X;
> ++/* { dg-warning "U\\+202C" "" { target *-*-* } .-1 } */
> ++int A\u202cY;
> ++/* { dg-warning "U\\+202C" "" { target *-*-* } .-1 } */
> ++int A\u202CY2;
> ++/* { dg-warning "U\\+202C" "" { target *-*-* } .-1 } */
> ++
> ++int d\u202ae\u202cf;
> ++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
> ++int d\u202Ae\u202cf2;
> ++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
> ++int d\u202be\u202cf;
> ++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
> ++int d\u202Be\u202cf2;
> ++/* { dg-warning "U\\+202B" "" { target *-*-* } .-1 } */
> ++int d\u202de\u202cf;
> ++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
> ++int d\u202De\u202cf2;
> ++/* { dg-warning "U\\+202D" "" { target *-*-* } .-1 } */
> ++int d\u202ee\u202cf;
> ++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
> ++int d\u202Ee\u202cf2;
> ++/* { dg-warning "U\\+202E" "" { target *-*-* } .-1 } */
> ++int d\u2066e\u2069f;
> ++/* { dg-warning "U\\+2066" "" { target *-*-* } .-1 } */
> ++int d\u2067e\u2069f;
> ++/* { dg-warning "U\\+2067" "" { target *-*-* } .-1 } */
> ++int d\u2068e\u2069f;
> ++/* { dg-warning "U\\+2068" "" { target *-*-* } .-1 } */
> ++int X\u2069;
> ++/* { dg-warning "U\\+2069" "" { target *-*-* } .-1 } */
> +diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-5.c
> b/gcc/testsuite/c-c++-common/Wbidi-chars-5.c
> +--- a/gcc/testsuite/c-c++-common/Wbidi-chars-5.c       1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-5.c       2021-12-25
> 01:36:22.048018559 -0800
> +@@ -0,0 +1,188 @@
> ++/* PR preprocessor/103026 */
> ++/* { dg-do compile } */
> ++/* { dg-options "-Wbidi-chars=unpaired -Wno-multichar -Wno-
> overflow" } */
> ++/* Test all bidi chars in various contexts (identifiers, comments,
> ++   string literals, character constants), both UCN and UTF-8.  The
> bidi
> ++   chars here are properly terminated, except for the character
> constants.  */
> ++
> ++/* a b c LRE‪ 1 2 3 PDF‬ x y z */
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++/* a b c RLE‫ 1 2 3 PDF‬ x y z */
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++/* a b c LRO‭ 1 2 3 PDF‬ x y z */
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++/* a b c RLO‮ 1 2 3 PDF‬ x y z */
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++/* a b c LRI⁦ 1 2 3 PDI⁩ x y z */
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++/* a b c RLI⁧ 1 2 3 PDI⁩ x y */
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++/* a b c FSI⁨ 1 2 3 PDI⁩ x y z */
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++
> ++/* Same but C++ comments instead.  */
> ++// a b c LRE‪ 1 2 3 PDF‬ x y z
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++// a b c RLE‫ 1 2 3 PDF‬ x y z
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++// a b c LRO‭ 1 2 3 PDF‬ x y z
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++// a b c RLO‮ 1 2 3 PDF‬ x y z
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++// a b c LRI⁦ 1 2 3 PDI⁩ x y z
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++// a b c RLI⁧ 1 2 3 PDI⁩ x y
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++// a b c FSI⁨ 1 2 3 PDI⁩ x y z
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++
> ++/* Here we're closing an unopened context, warn when =any.  */
> ++/* a b c PDI⁩ x y z */
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++/* a b c PDF‬ x y z */
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++// a b c PDI⁩ x y z
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++// a b c PDF‬ x y z
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++
> ++/* Multiline comments.  */
> ++/* a b c PDI⁩ x y z
> ++   */
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-2 } */
> ++/* a b c PDF‬ x y z
> ++   */
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-2 } */
> ++/* first
> ++   a b c PDI⁩ x y z
> ++   */
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-2 } */
> ++/* first
> ++   a b c PDF‬ x y z
> ++   */
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-2 } */
> ++/* first
> ++   a b c PDI⁩ x y z */
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++/* first
> ++   a b c PDF‬ x y z */
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++
> ++void
> ++g1 ()
> ++{
> ++  const char *s1 = "a b c LRE‪ 1 2 3 PDF‬ x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s2 = "a b c RLE‫ 1 2 3 PDF‬ x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s3 = "a b c LRO‭ 1 2 3 PDF‬ x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s4 = "a b c RLO‮ 1 2 3 PDF‬ x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s5 = "a b c LRI⁦ 1 2 3 PDI⁩ x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s6 = "a b c RLI⁧ 1 2 3 PDI⁩ x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s7 = "a b c FSI⁨ 1 2 3 PDI⁩ x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s8 = "a b c PDI⁩ x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s9 = "a b c PDF‬ x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++
> ++  const char *s10 = "a b c LRE\u202a 1 2 3 PDF\u202c x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s11 = "a b c LRE\u202A 1 2 3 PDF\u202c x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s12 = "a b c RLE\u202b 1 2 3 PDF\u202c x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s13 = "a b c RLE\u202B 1 2 3 PDF\u202c x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s14 = "a b c LRO\u202d 1 2 3 PDF\u202c x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s15 = "a b c LRO\u202D 1 2 3 PDF\u202c x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s16 = "a b c RLO\u202e 1 2 3 PDF\u202c x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s17 = "a b c RLO\u202E 1 2 3 PDF\u202c x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s18 = "a b c LRI\u2066 1 2 3 PDI\u2069 x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s19 = "a b c RLI\u2067 1 2 3 PDI\u2069 x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s20 = "a b c FSI\u2068 1 2 3 PDI\u2069 x y z";
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++}
> ++
> ++void
> ++g2 ()
> ++{
> ++  const char c1 = '\u202a';
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char c2 = '\u202A';
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char c3 = '\u202b';
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char c4 = '\u202B';
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char c5 = '\u202d';
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char c6 = '\u202D';
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char c7 = '\u202e';
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char c8 = '\u202E';
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char c9 = '\u2066';
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char c10 = '\u2067';
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char c11 = '\u2068';
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++}
> ++
> ++int a‪b‬c;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int a‫b‬c;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int a‭b‬c;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int a‮b‬c;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int a⁦b⁩c;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int a⁧b⁩c;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int a⁨b⁩c;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int A‬X;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int A\u202cY;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int A\u202CY2;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++
> ++int d\u202ae\u202cf;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int d\u202Ae\u202cf2;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int d\u202be\u202cf;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int d\u202Be\u202cf2;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int d\u202de\u202cf;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int d\u202De\u202cf2;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int d\u202ee\u202cf;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int d\u202Ee\u202cf2;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int d\u2066e\u2069f;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int d\u2067e\u2069f;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int d\u2068e\u2069f;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> ++int X\u2069;
> ++/* { dg-bogus "unpaired" "" { target *-*-* } .-1 } */
> +diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-6.c
> b/gcc/testsuite/c-c++-common/Wbidi-chars-6.c
> +--- a/gcc/testsuite/c-c++-common/Wbidi-chars-6.c       1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-6.c       2021-12-25
> 01:36:22.052018489 -0800
> +@@ -0,0 +1,155 @@
> ++/* PR preprocessor/103026 */
> ++/* { dg-do compile } */
> ++/* { dg-options "-Wbidi-chars=unpaired" } */
> ++/* Test nesting of bidi chars in various contexts.  */
> ++
> ++/* Terminated by the wrong char:  */
> ++/* a b c LRE‪ 1 2 3 PDI⁩ x y z */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++/* a b c RLE‫ 1 2 3 PDI⁩ x y  z*/
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++/* a b c LRO‭ 1 2 3 PDI⁩ x y z */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++/* a b c RLO‮ 1 2 3 PDI⁩ x y z */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++/* a b c LRI⁦ 1 2 3 PDF‬ x y z */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++/* a b c RLI⁧ 1 2 3 PDF‬ x y z */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++/* a b c FSI⁨ 1 2 3 PDF‬ x y  z*/
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++
> ++/* LRE‪ PDF‬ */
> ++/* LRE‪ LRE‪ PDF‬ PDF‬ */
> ++/* PDF‬ LRE‪ PDF‬ */
> ++/* LRE‪ PDF‬ LRE‪ PDF‬ */
> ++/* LRE‪ LRE‪ PDF‬ */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++/* PDF‬ LRE‪ */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++
> ++// a b c LRE‪ 1 2 3 PDI⁩ x y z
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++// a b c RLE‫ 1 2 3 PDI⁩ x y  z*/
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++// a b c LRO‭ 1 2 3 PDI⁩ x y z
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++// a b c RLO‮ 1 2 3 PDI⁩ x y z
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++// a b c LRI⁦ 1 2 3 PDF‬ x y z
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++// a b c RLI⁧ 1 2 3 PDF‬ x y z
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++// a b c FSI⁨ 1 2 3 PDF‬ x y  z
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++
> ++// LRE‪ PDF‬
> ++// LRE‪ LRE‪ PDF‬ PDF‬
> ++// PDF‬ LRE‪ PDF‬
> ++// LRE‪ PDF‬ LRE‪ PDF‬
> ++// LRE‪ LRE‪ PDF‬
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++// PDF‬ LRE‪
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++
> ++void
> ++g1 ()
> ++{
> ++  const char *s1 = "a b c LRE‪ 1 2 3 PDI⁩ x y z";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s2 = "a b c LRE\u202a 1 2 3 PDI\u2069 x y z";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s3 = "a b c RLE‫ 1 2 3 PDI⁩ x y ";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s4 = "a b c RLE\u202b 1 2 3 PDI\u2069 x y z";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s5 = "a b c LRO‭ 1 2 3 PDI⁩ x y z";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s6 = "a b c LRO\u202d 1 2 3 PDI\u2069 x y z";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s7 = "a b c RLO‮ 1 2 3 PDI⁩ x y z";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s8 = "a b c RLO\u202e 1 2 3 PDI\u2069 x y z";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s9 = "a b c LRI⁦ 1 2 3 PDF‬ x y z";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s10 = "a b c LRI\u2066 1 2 3 PDF\u202c x y z";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s11 = "a b c RLI⁧ 1 2 3 PDF‬ x y z\
> ++    ";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
> ++  const char *s12 = "a b c RLI\u2067 1 2 3 PDF\u202c x y z";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s13 = "a b c FSI⁨ 1 2 3 PDF‬ x y z";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s14 = "a b c FSI\u2068 1 2 3 PDF\u202c x y z";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s15 = "PDF‬ LRE‪";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s16 = "PDF\u202c LRE\u202a";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s17 = "LRE‪ PDF‬";
> ++  const char *s18 = "LRE\u202a PDF\u202c";
> ++  const char *s19 = "LRE‪ LRE‪ PDF‬ PDF‬";
> ++  const char *s20 = "LRE\u202a LRE\u202a PDF\u202c PDF\u202c";
> ++  const char *s21 = "PDF‬ LRE‪ PDF‬";
> ++  const char *s22 = "PDF\u202c LRE\u202a PDF\u202c";
> ++  const char *s23 = "LRE‪ LRE‪ PDF‬";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s24 = "LRE\u202a LRE\u202a PDF\u202c";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s25 = "PDF‬ LRE‪";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s26 = "PDF\u202c LRE\u202a";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s27 = "PDF‬ LRE\u202a";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++  const char *s28 = "PDF\u202c LRE‪";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++}
> ++
> ++int aLRE‪bPDI⁩;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int A\u202aB\u2069C;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int aRLE‫bPDI⁩;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int a\u202bB\u2069c;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int aLRO‭bPDI⁩;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int a\u202db\u2069c2;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int aRLO‮bPDI⁩;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int a\u202eb\u2069;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int aLRI⁦bPDF‬;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int a\u2066b\u202c;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int aRLI⁧bPDF‬c
> ++;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-2 } */
> ++int a\u2067b\u202c;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int aFSI⁨bPDF‬;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int a\u2068b\u202c;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int aFSI⁨bPD\u202C;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int aFSI\u2068bPDF‬_;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int aLRE‪bPDF‬b;
> ++int A\u202aB\u202c;
> ++int a_LRE‪_LRE‪_b_PDF‬_PDF‬;
> ++int A\u202aA\u202aB\u202cB\u202c;
> ++int aPDF‬bLREadPDF‬;
> ++int a_\u202C_\u202a_\u202c;
> ++int a_LRE‪_b_PDF‬_c_LRE‪_PDF‬;
> ++int a_\u202a_\u202c_\u202a_\u202c_;
> ++int a_LRE‪_b_PDF‬_c_LRE‪;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int a_\u202a_\u202c_\u202a_;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> +diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-7.c
> b/gcc/testsuite/c-c++-common/Wbidi-chars-7.c
> +--- a/gcc/testsuite/c-c++-common/Wbidi-chars-7.c       1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-7.c       2021-12-25
> 01:36:22.052018489 -0800
> +@@ -0,0 +1,9 @@
> ++/* PR preprocessor/103026 */
> ++/* { dg-do compile } */
> ++/* { dg-options "-Wbidi-chars=any" } */
> ++/* Test we ignore UCNs in comments.  */
> ++
> ++// a b c \u202a 1 2 3
> ++// a b c \u202A 1 2 3
> ++/* a b c \u202a 1 2 3 */
> ++/* a b c \u202A 1 2 3 */
> +diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-8.c
> b/gcc/testsuite/c-c++-common/Wbidi-chars-8.c
> +--- a/gcc/testsuite/c-c++-common/Wbidi-chars-8.c       1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-8.c       2021-12-25
> 01:36:22.052018489 -0800
> +@@ -0,0 +1,13 @@
> ++/* PR preprocessor/103026 */
> ++/* { dg-do compile } */
> ++/* { dg-options "-Wbidi-chars=any" } */
> ++/* Test \u vs \U.  */
> ++
> ++int a_\u202A;
> ++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
> ++int a_\u202a_2;
> ++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
> ++int a_\U0000202A_3;
> ++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
> ++int a_\U0000202a_4;
> ++/* { dg-warning "U\\+202A" "" { target *-*-* } .-1 } */
> +diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-9.c
> b/gcc/testsuite/c-c++-common/Wbidi-chars-9.c
> +--- a/gcc/testsuite/c-c++-common/Wbidi-chars-9.c       1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-9.c       2021-12-25
> 01:36:22.052018489 -0800
> +@@ -0,0 +1,29 @@
> ++/* PR preprocessor/103026 */
> ++/* { dg-do compile } */
> ++/* { dg-options "-Wbidi-chars=unpaired" } */
> ++/* Test that we properly separate bidi contexts
> (comment/identifier/character
> ++   constant/string literal).  */
> ++
> ++/* LRE ->‪<- */ int pdf_\u202c_1;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++/* RLE ->‫<- */ int pdf_\u202c_2;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++/* LRO ->‭<- */ int pdf_\u202c_3;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++/* RLO ->‮<- */ int pdf_\u202c_4;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++/* LRI ->⁦<-*/ int pdi_\u2069_1;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++/* RLI ->⁧<- */ int pdi_\u2069_12;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++/* FSI ->⁨<- */ int pdi_\u2069_3;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++
> ++const char *s1 = "LRE\u202a"; /* PDF ->‬<- */
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++/* LRE ->‪<- */ const char *s2 = "PDF\u202c";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++const char *s3 = "LRE\u202a"; int pdf_\u202c_5;
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> ++int lre_\u202a; const char *s4 = "PDF\u202c";
> ++/* { dg-warning "unpaired" "" { target *-*-* } .-1 } */
> +diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
> +--- a/libcpp/include/cpplib.h  2021-12-25 01:35:33.288883417 -0800
> ++++ b/libcpp/include/cpplib.h  2021-12-25 01:36:22.052018489 -0800
> +@@ -308,6 +308,17 @@ enum cpp_normalize_level {
> +   normalized_none
> + };
> +
> ++/* The possible bidirectional control characters checking levels,
> from least
> ++   restrictive to most.  */
> ++enum cpp_bidirectional_level {
> ++  /* No checking.  */
> ++  bidirectional_none,
> ++  /* Only detect unpaired uses of bidirectional control
> characters.  */
> ++  bidirectional_unpaired,
> ++  /* Detect any use of bidirectional control characters.  */
> ++  bidirectional_any
> ++};
> ++
> + /* This structure is nested inside struct cpp_reader, and
> +    carries all the options visible to the command line.  */
> + struct cpp_options
> +@@ -515,6 +526,10 @@ struct cpp_options
> +   /* True if warn about differences between C++98 and C++11.  */
> +   bool cpp_warn_cxx11_compat;
> +
> ++  /* Nonzero if bidirectional control characters checking is on.
> See enum
> ++     cpp_bidirectional_level.  */
> ++  unsigned char cpp_warn_bidirectional;
> ++
> +   /* Dependency generation.  */
> +   struct
> +   {
> +@@ -613,7 +628,8 @@ enum cpp_warning_reason {
> +   CPP_W_C90_C99_COMPAT,
> +   CPP_W_C11_C2X_COMPAT,
> +   CPP_W_CXX11_COMPAT,
> +-  CPP_W_EXPANSION_TO_DEFINED
> ++  CPP_W_EXPANSION_TO_DEFINED,
> ++  CPP_W_BIDIRECTIONAL
> + };
> +
> + /* Callback for header lookup for HEADER, which is the name of a
> +diff --git a/libcpp/init.c b/libcpp/init.c
> +--- a/libcpp/init.c    2021-12-25 01:29:12.931317107 -0800
> ++++ b/libcpp/init.c    2021-12-25 01:36:22.052018489 -0800
> +@@ -215,6 +215,7 @@ cpp_create_reader (enum c_lang lang, cpp
> +       = ENABLE_CANONICAL_SYSTEM_HEADERS;
> +   CPP_OPTION (pfile, ext_numeric_literals) = 1;
> +   CPP_OPTION (pfile, warn_date_time) = 0;
> ++  CPP_OPTION (pfile, cpp_warn_bidirectional) =
> bidirectional_unpaired;
> +
> +   /* Default CPP arithmetic to something sensible for the host for
> the
> +      benefit of dumb users like fix-header.  */
> +diff --git a/libcpp/internal.h b/libcpp/internal.h
> +--- a/libcpp/internal.h        2021-12-25 01:35:33.288883417 -0800
> ++++ b/libcpp/internal.h        2021-12-25 01:36:22.052018489 -0800
> +@@ -581,6 +581,10 @@ struct cpp_reader
> +   /* If non-zero, the lexer will use this location for the next
> token
> +      instead of getting a location from the linemap.  */
> +   location_t forced_token_location;
> ++  bool warn_bidi_p () const
> ++  {
> ++    return CPP_OPTION (this, cpp_warn_bidirectional) !=
> bidirectional_none;
> ++  }
> + };
> +
> + /* Character classes.  Based on the more primitive macros in safe-
> ctype.h.
> +diff --git a/libcpp/lex.c b/libcpp/lex.c
> +--- a/libcpp/lex.c     2021-12-25 01:35:33.288883417 -0800
> ++++ b/libcpp/lex.c     2021-12-25 01:36:22.052018489 -0800
> +@@ -1164,6 +1164,324 @@ _cpp_process_line_notes (cpp_reader *pfi
> +     }
> + }
> +
> ++namespace bidi {
> ++  enum class kind {
> ++    NONE, LRE, RLE, LRO, RLO, LRI, RLI, FSI, PDF, PDI, LTR, RTL
> ++  };
> ++
> ++  /* All the UTF-8 encodings of bidi characters start with E2.  */
> ++  constexpr uchar utf8_start = 0xe2;
> ++
> ++  /* A vector holding currently open bidi contexts.  We use a char
> for
> ++     each context, its LSB is 1 if it represents a PDF context, 0
> if it
> ++     represents a PDI context.  The next bit is 1 if this context
> was open
> ++     by a bidi character written as a UCN, and 0 when it was UTF-
> 8.  */
> ++  semi_embedded_vec <unsigned char, 16> vec;
> ++
> ++  /* Close the whole comment/identifier/string literal/character
> constant
> ++     context.  */
> ++  void on_close ()
> ++  {
> ++    vec.truncate (0);
> ++  }
> ++
> ++  /* Pop the last element in the vector.  */
> ++  void pop ()
> ++  {
> ++    unsigned int len = vec.count ();
> ++    gcc_checking_assert (len > 0);
> ++    vec.truncate (len - 1);
> ++  }
> ++
> ++  /* Return the context of the Ith element.  */
> ++  kind ctx_at (unsigned int i)
> ++  {
> ++    return (vec[i] & 1) ? kind::PDF : kind::PDI;
> ++  }
> ++
> ++  /* Return which context is currently opened.  */
> ++  kind current_ctx ()
> ++  {
> ++    unsigned int len = vec.count ();
> ++    if (len == 0)
> ++      return kind::NONE;
> ++    return ctx_at (len - 1);
> ++  }
> ++
> ++  /* Return true if the current context comes from a UCN origin,
> that is,
> ++     the bidi char which started this bidi context was written as a
> UCN.  */
> ++  bool current_ctx_ucn_p ()
> ++  {
> ++    unsigned int len = vec.count ();
> ++    gcc_checking_assert (len > 0);
> ++    return (vec[len - 1] >> 1) & 1;
> ++  }
> ++
> ++  /* We've read a bidi char, update the current vector as
> necessary.  */
> ++  void on_char (kind k, bool ucn_p)
> ++  {
> ++    switch (k)
> ++      {
> ++      case kind::LRE:
> ++      case kind::RLE:
> ++      case kind::LRO:
> ++      case kind::RLO:
> ++      vec.push (ucn_p ? 3u : 1u);
> ++      break;
> ++      case kind::LRI:
> ++      case kind::RLI:
> ++      case kind::FSI:
> ++      vec.push (ucn_p ? 2u : 0u);
> ++      break;
> ++      /* PDF terminates the scope of the last LRE, RLE, LRO, or RLO
> ++       whose scope has not yet been terminated.  */
> ++      case kind::PDF:
> ++      if (current_ctx () == kind::PDF)
> ++        pop ();
> ++      break;
> ++      /* PDI terminates the scope of the last LRI, RLI, or FSI
> whose
> ++       scope has not yet been terminated, as well as the scopes of
> ++       any subsequent LREs, RLEs, LROs, or RLOs whose scopes have
> not
> ++       yet been terminated.  */
> ++      case kind::PDI:
> ++      for (int i = vec.count () - 1; i >= 0; --i)
> ++        if (ctx_at (i) == kind::PDI)
> ++          {
> ++            vec.truncate (i);
> ++            break;
> ++          }
> ++      break;
> ++      case kind::LTR:
> ++      case kind::RTL:
> ++      /* These aren't popped by a PDF/PDI.  */
> ++      break;
> ++      [[likely]] case kind::NONE:
> ++      break;
> ++      default:
> ++      abort ();
> ++      }
> ++  }
> ++
> ++  /* Return a descriptive string for K.  */
> ++  const char *to_str (kind k)
> ++  {
> ++    switch (k)
> ++      {
> ++      case kind::LRE:
> ++      return "U+202A (LEFT-TO-RIGHT EMBEDDING)";
> ++      case kind::RLE:
> ++      return "U+202B (RIGHT-TO-LEFT EMBEDDING)";
> ++      case kind::LRO:
> ++      return "U+202D (LEFT-TO-RIGHT OVERRIDE)";
> ++      case kind::RLO:
> ++      return "U+202E (RIGHT-TO-LEFT OVERRIDE)";
> ++      case kind::LRI:
> ++      return "U+2066 (LEFT-TO-RIGHT ISOLATE)";
> ++      case kind::RLI:
> ++      return "U+2067 (RIGHT-TO-LEFT ISOLATE)";
> ++      case kind::FSI:
> ++      return "U+2068 (FIRST STRONG ISOLATE)";
> ++      case kind::PDF:
> ++      return "U+202C (POP DIRECTIONAL FORMATTING)";
> ++      case kind::PDI:
> ++      return "U+2069 (POP DIRECTIONAL ISOLATE)";
> ++      case kind::LTR:
> ++      return "U+200E (LEFT-TO-RIGHT MARK)";
> ++      case kind::RTL:
> ++      return "U+200F (RIGHT-TO-LEFT MARK)";
> ++      default:
> ++      abort ();
> ++      }
> ++  }
> ++}
> ++
> ++/* Parse a sequence of 3 bytes starting with P and return its bidi
> code.  */
> ++
> ++static bidi::kind
> ++get_bidi_utf8 (const unsigned char *const p)
> ++{
> ++  gcc_checking_assert (p[0] == bidi::utf8_start);
> ++
> ++  if (p[1] == 0x80)
> ++    switch (p[2])
> ++      {
> ++      case 0xaa:
> ++      return bidi::kind::LRE;
> ++      case 0xab:
> ++      return bidi::kind::RLE;
> ++      case 0xac:
> ++      return bidi::kind::PDF;
> ++      case 0xad:
> ++      return bidi::kind::LRO;
> ++      case 0xae:
> ++      return bidi::kind::RLO;
> ++      case 0x8e:
> ++      return bidi::kind::LTR;
> ++      case 0x8f:
> ++      return bidi::kind::RTL;
> ++      default:
> ++      break;
> ++      }
> ++  else if (p[1] == 0x81)
> ++    switch (p[2])
> ++      {
> ++      case 0xa6:
> ++      return bidi::kind::LRI;
> ++      case 0xa7:
> ++      return bidi::kind::RLI;
> ++      case 0xa8:
> ++      return bidi::kind::FSI;
> ++      case 0xa9:
> ++      return bidi::kind::PDI;
> ++      default:
> ++      break;
> ++      }
> ++
> ++  return bidi::kind::NONE;
> ++}
> ++
> ++/* Parse a UCN where P points just past \u or \U and return its
> bidi code.  */
> ++
> ++static bidi::kind
> ++get_bidi_ucn (const unsigned char *p, bool is_U)
> ++{
> ++  /* 6.4.3 Universal Character Names
> ++      \u hex-quad
> ++      \U hex-quad hex-quad
> ++     where \unnnn means \U0000nnnn.  */
> ++
> ++  if (is_U)
> ++    {
> ++      if (p[0] != '0' || p[1] != '0' || p[2] != '0' || p[3] != '0')
> ++      return bidi::kind::NONE;
> ++      /* Skip 4B so we can treat \u and \U the same below.  */
> ++      p += 4;
> ++    }
> ++
> ++  /* All code points we are looking for start with 20xx.  */
> ++  if (p[0] != '2' || p[1] != '0')
> ++    return bidi::kind::NONE;
> ++  else if (p[2] == '2')
> ++    switch (p[3])
> ++      {
> ++      case 'a':
> ++      case 'A':
> ++      return bidi::kind::LRE;
> ++      case 'b':
> ++      case 'B':
> ++      return bidi::kind::RLE;
> ++      case 'c':
> ++      case 'C':
> ++      return bidi::kind::PDF;
> ++      case 'd':
> ++      case 'D':
> ++      return bidi::kind::LRO;
> ++      case 'e':
> ++      case 'E':
> ++      return bidi::kind::RLO;
> ++      default:
> ++      break;
> ++      }
> ++  else if (p[2] == '6')
> ++    switch (p[3])
> ++      {
> ++      case '6':
> ++      return bidi::kind::LRI;
> ++      case '7':
> ++      return bidi::kind::RLI;
> ++      case '8':
> ++      return bidi::kind::FSI;
> ++      case '9':
> ++      return bidi::kind::PDI;
> ++      default:
> ++      break;
> ++      }
> ++  else if (p[2] == '0')
> ++    switch (p[3])
> ++      {
> ++      case 'e':
> ++      case 'E':
> ++      return bidi::kind::LTR;
> ++      case 'f':
> ++      case 'F':
> ++      return bidi::kind::RTL;
> ++      default:
> ++      break;
> ++      }
> ++
> ++  return bidi::kind::NONE;
> ++}
> ++
> ++/* We're closing a bidi context, that is, we've encountered a
> newline,
> ++   are closing a C-style comment, or are at the end of a string
> literal,
> ++   character constant, or identifier.  Warn if this context was not
> ++   properly terminated by a PDI or PDF.  P points to the last
> character
> ++   in this context.  */
> ++
> ++static void
> ++maybe_warn_bidi_on_close (cpp_reader *pfile, const uchar *p)
> ++{
> ++  if (CPP_OPTION (pfile, cpp_warn_bidirectional) ==
> bidirectional_unpaired
> ++      && bidi::vec.count () > 0)
> ++    {
> ++      const location_t loc
> ++      = linemap_position_for_column (pfile->line_table,
> ++                                     CPP_BUF_COLUMN (pfile->buffer,
> p));
> ++      cpp_warning_with_line (pfile, CPP_W_BIDIRECTIONAL, loc, 0,
> ++                           "unpaired UTF-8 bidirectional control
> character "
> ++                           "detected");
> ++    }
> ++  /* We're done with this context.  */
> ++  bidi::on_close ();
> ++}
> ++
> ++/* We're at the beginning or in the middle of an
> identifier/comment/string
> ++   literal/character constant.  Warn if we've encountered a bidi
> character.
> ++   KIND says which bidi character it was; P points to it in the
> character
> ++   stream.  UCN_P is true iff this bidi character was written as a
> UCN.  */
> ++
> ++static void
> ++maybe_warn_bidi_on_char (cpp_reader *pfile, const uchar *p,
> bidi::kind kind,
> ++                       bool ucn_p)
> ++{
> ++  if (__builtin_expect (kind == bidi::kind::NONE, 1))
> ++    return;
> ++
> ++  const auto warn_bidi = CPP_OPTION (pfile,
> cpp_warn_bidirectional);
> ++
> ++  if (warn_bidi != bidirectional_none)
> ++    {
> ++      const location_t loc
> ++      = linemap_position_for_column (pfile->line_table,
> ++                                     CPP_BUF_COLUMN (pfile->buffer,
> p));
> ++      /* It seems excessive to warn about a PDI/PDF that is closing
> ++       an opened context because we've already warned about the
> ++       opening character.  Except warn when we have a UCN x UTF-8
> ++       mismatch.  */
> ++      if (kind == bidi::current_ctx ())
> ++      {
> ++        if (warn_bidi == bidirectional_unpaired
> ++            && bidi::current_ctx_ucn_p () != ucn_p)
> ++          cpp_warning_with_line (pfile, CPP_W_BIDIRECTIONAL, loc,
> 0,
> ++                                 "UTF-8 vs UCN mismatch when
> closing "
> ++                                 "a context by \"%s\"",
> bidi::to_str (kind));
> ++      }
> ++      else if (warn_bidi == bidirectional_any)
> ++      {
> ++        if (kind == bidi::kind::PDF || kind == bidi::kind::PDI)
> ++          cpp_warning_with_line (pfile, CPP_W_BIDIRECTIONAL, loc,
> 0,
> ++                                 "\"%s\" is closing an unopened
> context",
> ++                                 bidi::to_str (kind));
> ++        else
> ++          cpp_warning_with_line (pfile, CPP_W_BIDIRECTIONAL, loc,
> 0,
> ++                                 "found problematic Unicode
> character \"%s\"",
> ++                                 bidi::to_str (kind));
> ++      }
> ++    }
> ++  /* We're done with this context.  */
> ++  bidi::on_char (kind, ucn_p);
> ++}
> ++
> + /* Skip a C-style block comment.  We find the end of the comment by
> +    seeing if an asterisk is before every '/' we encounter.  Returns
> +    nonzero if comment terminated by EOF, zero otherwise.
> +@@ -1175,6 +1493,7 @@ _cpp_skip_block_comment (cpp_reader *pfi
> +   cpp_buffer *buffer = pfile->buffer;
> +   const uchar *cur = buffer->cur;
> +   uchar c;
> ++  const bool warn_bidi_p = pfile->warn_bidi_p ();
> +
> +   cur++;
> +   if (*cur == '/')
> +@@ -1189,7 +1508,11 @@ _cpp_skip_block_comment (cpp_reader *pfi
> +       if (c == '/')
> +       {
> +         if (cur[-2] == '*')
> +-          break;
> ++          {
> ++            if (warn_bidi_p)
> ++              maybe_warn_bidi_on_close (pfile, cur);
> ++            break;
> ++          }
> +
> +         /* Warn about potential nested comments, but not if the '/'
> +            comes immediately before the true comment delimiter.
> +@@ -1208,6 +1531,8 @@ _cpp_skip_block_comment (cpp_reader *pfi
> +       {
> +         unsigned int cols;
> +         buffer->cur = cur - 1;
> ++        if (warn_bidi_p)
> ++          maybe_warn_bidi_on_close (pfile, cur);
> +         _cpp_process_line_notes (pfile, true);
> +         if (buffer->next_line >= buffer->rlimit)
> +           return true;
> +@@ -1218,6 +1543,13 @@ _cpp_skip_block_comment (cpp_reader *pfi
> +
> +         cur = buffer->cur;
> +       }
> ++      /* If this is a beginning of a UTF-8 encoding, it might be
> ++       a bidirectional control character.  */
> ++      else if (__builtin_expect (c == bidi::utf8_start, 0) &&
> warn_bidi_p)
> ++      {
> ++        bidi::kind kind = get_bidi_utf8 (cur - 1);
> ++        maybe_warn_bidi_on_char (pfile, cur, kind,
> /*ucn_p=*/false);
> ++      }
> +     }
> +
> +   buffer->cur = cur;
> +@@ -1233,9 +1565,31 @@ skip_line_comment (cpp_reader *pfile)
> + {
> +   cpp_buffer *buffer = pfile->buffer;
> +   location_t orig_line = pfile->line_table->highest_line;
> ++  const bool warn_bidi_p = pfile->warn_bidi_p ();
> +
> +-  while (*buffer->cur != '\n')
> +-    buffer->cur++;
> ++  if (!warn_bidi_p)
> ++    while (*buffer->cur != '\n')
> ++      buffer->cur++;
> ++  else
> ++    {
> ++      while (*buffer->cur != '\n'
> ++           && *buffer->cur != bidi::utf8_start)
> ++      buffer->cur++;
> ++      if (__builtin_expect (*buffer->cur == bidi::utf8_start, 0))
> ++      {
> ++        while (*buffer->cur != '\n')
> ++          {
> ++            if (__builtin_expect (*buffer->cur == bidi::utf8_start,
> 0))
> ++              {
> ++                bidi::kind kind = get_bidi_utf8 (buffer->cur);
> ++                maybe_warn_bidi_on_char (pfile, buffer->cur, kind,
> ++                                         /*ucn_p=*/false);
> ++              }
> ++            buffer->cur++;
> ++          }
> ++        maybe_warn_bidi_on_close (pfile, buffer->cur);
> ++      }
> ++    }
> +
> +   _cpp_process_line_notes (pfile, true);
> +   return orig_line != pfile->line_table->highest_line;
> +@@ -1343,11 +1697,13 @@ static const cppchar_t utf8_signifier =
> +
> + /* Returns TRUE if the sequence starting at buffer->cur is valid in
> +    an identifier.  FIRST is TRUE if this starts an identifier.  */
> ++
> + static bool
> + forms_identifier_p (cpp_reader *pfile, int first,
> +                   struct normalize_state *state)
> + {
> +   cpp_buffer *buffer = pfile->buffer;
> ++  const bool warn_bidi_p = pfile->warn_bidi_p ();
> +
> +   if (*buffer->cur == '$')
> +     {
> +@@ -1370,6 +1726,13 @@ forms_identifier_p (cpp_reader *pfile, i
> +       cppchar_t s;
> +       if (*buffer->cur >= utf8_signifier)
> +       {
> ++        if (__builtin_expect (*buffer->cur == bidi::utf8_start, 0)
> ++            && warn_bidi_p)
> ++          {
> ++            bidi::kind kind = get_bidi_utf8 (buffer->cur);
> ++            maybe_warn_bidi_on_char (pfile, buffer->cur, kind,
> ++                                     /*ucn_p=*/false);
> ++          }
> +         if (_cpp_valid_utf8 (pfile, &buffer->cur, buffer->rlimit, 1
> + !first,
> +                              state, &s))
> +           return true;
> +@@ -1378,6 +1741,13 @@ forms_identifier_p (cpp_reader *pfile, i
> +              && (buffer->cur[1] == 'u' || buffer->cur[1] == 'U'))
> +       {
> +         buffer->cur += 2;
> ++        if (warn_bidi_p)
> ++          {
> ++            bidi::kind kind = get_bidi_ucn (buffer->cur,
> ++                                            buffer->cur[-1] ==
> 'U');
> ++            maybe_warn_bidi_on_char (pfile, buffer->cur, kind,
> ++                                     /*ucn_p=*/true);
> ++          }
> +         if (_cpp_valid_ucn (pfile, &buffer->cur, buffer->rlimit, 1
> + !first,
> +                             state, &s, NULL, NULL))
> +           return true;
> +@@ -1486,6 +1856,7 @@ lex_identifier (cpp_reader *pfile, const
> +   const uchar *cur;
> +   unsigned int len;
> +   unsigned int hash = HT_HASHSTEP (0, *base);
> ++  const bool warn_bidi_p = pfile->warn_bidi_p ();
> +
> +   cur = pfile->buffer->cur;
> +   if (! starts_ucn)
> +@@ -1509,6 +1880,8 @@ lex_identifier (cpp_reader *pfile, const
> +           pfile->buffer->cur++;
> +         }
> +       } while (forms_identifier_p (pfile, false, nst));
> ++      if (warn_bidi_p)
> ++      maybe_warn_bidi_on_close (pfile, pfile->buffer->cur);
> +       result = _cpp_interpret_identifier (pfile, base,
> +                                         pfile->buffer->cur - base);
> +       *spelling = cpp_lookup (pfile, base, pfile->buffer->cur -
> base);
> +@@ -1697,6 +2070,7 @@ lex_raw_string (cpp_reader *pfile, cpp_t
> + {
> +   uchar raw_prefix[17];
> +   uchar temp_buffer[18];
> ++  const bool warn_bidi_p = pfile->warn_bidi_p ();
> +   const uchar *orig_base;
> +   unsigned int raw_prefix_len = 0, raw_suffix_len = 0;
> +   enum raw_str_phase { RAW_STR_PREFIX, RAW_STR, RAW_STR_SUFFIX };
> +@@ -1946,8 +2320,15 @@ lex_raw_string (cpp_reader *pfile, cpp_t
> +         cur = base = pfile->buffer->cur;
> +         note = &pfile->buffer->notes[pfile->buffer->cur_note];
> +       }
> ++      else if (__builtin_expect ((unsigned char) c ==
> bidi::utf8_start, 0)
> ++             && warn_bidi_p)
> ++      maybe_warn_bidi_on_char (pfile, pos - 1, get_bidi_utf8 (pos -
> 1),
> ++                               /*ucn_p=*/false);
> +     }
> +
> ++  if (warn_bidi_p)
> ++    maybe_warn_bidi_on_close (pfile, pos);
> ++
> +   if (CPP_OPTION (pfile, user_literals))
> +     {
> +       /* If a string format macro, say from inttypes.h, is placed
> touching
> +@@ -2042,15 +2423,27 @@ lex_string (cpp_reader *pfile, cpp_token
> +   else
> +     terminator = '>', type = CPP_HEADER_NAME;
> +
> ++  const bool warn_bidi_p = pfile->warn_bidi_p ();
> +   for (;;)
> +     {
> +       cppchar_t c = *cur++;
> +
> +       /* In #include-style directives, terminators are not
> escapable.  */
> +       if (c == '\\' && !pfile->state.angled_headers && *cur !=
> '\n')
> +-      cur++;
> ++      {
> ++        if ((cur[0] == 'u' || cur[0] == 'U') && warn_bidi_p)
> ++          {
> ++            bidi::kind kind = get_bidi_ucn (cur + 1, cur[0] ==
> 'U');
> ++            maybe_warn_bidi_on_char (pfile, cur, kind,
> /*ucn_p=*/true);
> ++          }
> ++        cur++;
> ++      }
> +       else if (c == terminator)
> +-      break;
> ++      {
> ++        if (warn_bidi_p)
> ++          maybe_warn_bidi_on_close (pfile, cur - 1);
> ++        break;
> ++      }
> +       else if (c == '\n')
> +       {
> +         cur--;
> +@@ -2067,6 +2460,11 @@ lex_string (cpp_reader *pfile, cpp_token
> +       }
> +       else if (c == '\0')
> +       saw_NUL = true;
> ++      else if (__builtin_expect (c == bidi::utf8_start, 0) &&
> warn_bidi_p)
> ++      {
> ++        bidi::kind kind = get_bidi_utf8 (cur - 1);
> ++        maybe_warn_bidi_on_char (pfile, cur - 1, kind,
> /*ucn_p=*/false);
> ++      }
> +     }
> +
> +   if (saw_NUL && !pfile->state.skipping)
> diff --git a/meta/recipes-devtools/gcc/gcc/0004-CVE-2021-42574.patch
> b/meta/recipes-devtools/gcc/gcc/0004-CVE-2021-42574.patch
> new file mode 100644
> index 0000000000..877b8a6452
> --- /dev/null
> +++ b/meta/recipes-devtools/gcc/gcc/0004-CVE-2021-42574.patch
> @@ -0,0 +1,138 @@
> +From 1a7f2c0774129750fdf73e9f1b78f0ce983c9ab3 Mon Sep 17 00:00:00
> 2001
> +From: David Malcolm <dmalcolm@redhat.com>
> +Date: Tue, 2 Nov 2021 09:54:32 -0400
> +Subject: [PATCH] libcpp: escape non-ASCII source bytes in -Wbidi-
> chars=
> + [PR103026]
> +MIME-Version: 1.0
> +Content-Type: text/plain; charset=utf8
> +Content-Transfer-Encoding: 8bit
> +
> +This flags rich_locations associated with -Wbidi-chars= so that
> +non-ASCII bytes will be escaped when printing the source lines
> +(using the diagnostics support I added in
> +r12-4825-gbd5e882cf6e0def3dd1bc106075d59a303fe0d1e).
> +
> +In particular, this ensures that the printed source lines will
> +be pure ASCII, and thus the visual ordering of the characters
> +will be the same as the logical ordering.
> +
> +Before:
> +
> +  Wbidi-chars-1.c: In function âmainâ:
> +  Wbidi-chars-1.c:6:43: warning: unpaired UTF-8 bidirectional
> control character detected [-Wbidi-chars=]
> +      6 |     /*â® } â¦if (isAdmin)â© â¦ begin admins only */
> +        |                                           ^
> +  Wbidi-chars-1.c:9:28: warning: unpaired UTF-8 bidirectional
> control character detected [-Wbidi-chars=]
> +      9 |     /* end admins only â® { â¦*/
> +        |                            ^
> +
> +  Wbidi-chars-11.c:6:15: warning: UTF-8 vs UCN mismatch when closing
> a context by "U+202C (POP DIRECTIONAL FORMATTING)" [-Wbidi-chars=]
> +      6 | int LRE_âª_PDF_\u202c;
> +        |               ^
> +  Wbidi-chars-11.c:8:19: warning: UTF-8 vs UCN mismatch when closing
> a context by "U+202C (POP DIRECTIONAL FORMATTING)" [-Wbidi-chars=]
> +      8 | int LRE_\u202a_PDF_â¬_;
> +        |                   ^
> +  Wbidi-chars-11.c:10:28: warning: UTF-8 vs UCN mismatch when
> closing a context by "U+202C (POP DIRECTIONAL FORMATTING)" [-Wbidi-
> chars=]
> +     10 | const char *s1 = "LRE_âª_PDF_\u202c";
> +        |                            ^
> +  Wbidi-chars-11.c:12:33: warning: UTF-8 vs UCN mismatch when
> closing a context by "U+202C (POP DIRECTIONAL FORMATTING)" [-Wbidi-
> chars=]
> +     12 | const char *s2 = "LRE_\u202a_PDF_â¬";
> +        |                                 ^
> +
> +After:
> +
> +  Wbidi-chars-1.c: In function âmainâ:
> +  Wbidi-chars-1.c:6:43: warning: unpaired UTF-8 bidirectional
> control character detected [-Wbidi-chars=]
> +      6 |     /*<U+202E> } <U+2066>if (isAdmin)<U+2069> <U+2066>
> begin admins only */
> +
> |
>        ^
> +  Wbidi-chars-1.c:9:28: warning: unpaired UTF-8 bidirectional
> control character detected [-Wbidi-chars=]
> +      9 |     /* end admins only <U+202E> { <U+2066>*/
> +        |                                            ^
> +
> +  Wbidi-chars-11.c:6:15: warning: UTF-8 vs UCN mismatch when closing
> a context by "U+202C (POP DIRECTIONAL FORMATTING)" [-Wbidi-chars=]
> +      6 | int LRE_<U+202A>_PDF_\u202c;
> +        |                       ^
> +  Wbidi-chars-11.c:8:19: warning: UTF-8 vs UCN mismatch when closing
> a context by "U+202C (POP DIRECTIONAL FORMATTING)" [-Wbidi-chars=]
> +      8 | int LRE_\u202a_PDF_<U+202C>_;
> +        |                   ^
> +  Wbidi-chars-11.c:10:28: warning: UTF-8 vs UCN mismatch when
> closing a context by "U+202C (POP DIRECTIONAL FORMATTING)" [-Wbidi-
> chars=]
> +     10 | const char *s1 = "LRE_<U+202A>_PDF_\u202c";
> +        |                                    ^
> +  Wbidi-chars-11.c:12:33: warning: UTF-8 vs UCN mismatch when
> closing a context by "U+202C (POP DIRECTIONAL FORMATTING)" [-Wbidi-
> chars=]
> +     12 | const char *s2 = "LRE_\u202a_PDF_<U+202C>";
> +        |                                 ^
> +
> +libcpp/ChangeLog:
> +       PR preprocessor/103026
> +       * lex.c (maybe_warn_bidi_on_close): Use a rich_location
> +       and call set_escape_on_output (true) on it.
> +       (maybe_warn_bidi_on_char): Likewise.
> +
> +Signed-off-by: David Malcolm <dmalcolm@redhat.com>
> +
> +CVE: CVE-2021-42574
> +Upstream-Status: Backport
> [https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=1a7f2c0774129750fdf73
> e9f1b78f0ce983c9ab3]
> +Signed-off-by: Pgowda <pgowda.cve@gmail.com>
> +
> +---
> + libcpp/lex.c | 29 +++++++++++++++++------------
> + 1 file changed, 17 insertions(+), 12 deletions(-)
> +
> +diff --git a/libcpp/lex.c b/libcpp/lex.c
> +--- a/libcpp/lex.c     2021-12-14 20:44:11.647815287 -0800
> ++++ b/libcpp/lex.c     2021-12-14 20:43:38.008383220 -0800
> +@@ -1427,9 +1427,11 @@ maybe_warn_bidi_on_close (cpp_reader *pf
> +       const location_t loc
> +       = linemap_position_for_column (pfile->line_table,
> +                                      CPP_BUF_COLUMN (pfile->buffer,
> p));
> +-      cpp_warning_with_line (pfile, CPP_W_BIDIRECTIONAL, loc, 0,
> +-                           "unpaired UTF-8 bidirectional control
> character "
> +-                           "detected");
> ++      rich_location rich_loc (pfile->line_table, loc);
> ++      rich_loc.set_escape_on_output (true);
> ++      cpp_warning_at (pfile, CPP_W_BIDIRECTIONAL, &rich_loc,
> ++                    "unpaired UTF-8 bidirectional control character
> "
> ++                    "detected");
> +     }
> +   /* We're done with this context.  */
> +   bidi::on_close ();
> +@@ -1454,6 +1456,9 @@ maybe_warn_bidi_on_char (cpp_reader *pfi
> +       const location_t loc
> +       = linemap_position_for_column (pfile->line_table,
> +                                      CPP_BUF_COLUMN (pfile->buffer,
> p));
> ++      rich_location rich_loc (pfile->line_table, loc);
> ++      rich_loc.set_escape_on_output (true);
> ++
> +       /* It seems excessive to warn about a PDI/PDF that is closing
> +        an opened context because we've already warned about the
> +        opening character.  Except warn when we have a UCN x UTF-8
> +@@ -1462,20 +1467,20 @@ maybe_warn_bidi_on_char (cpp_reader *pfi
> +       {
> +         if (warn_bidi == bidirectional_unpaired
> +             && bidi::current_ctx_ucn_p () != ucn_p)
> +-          cpp_warning_with_line (pfile, CPP_W_BIDIRECTIONAL, loc,
> 0,
> +-                                 "UTF-8 vs UCN mismatch when
> closing "
> +-                                 "a context by \"%s\"",
> bidi::to_str (kind));
> ++          cpp_warning_at (pfile, CPP_W_BIDIRECTIONAL, &rich_loc,
> ++                          "UTF-8 vs UCN mismatch when closing "
> ++                          "a context by \"%s\"", bidi::to_str
> (kind));
> +       }
> +       else if (warn_bidi == bidirectional_any)
> +       {
> +         if (kind == bidi::kind::PDF || kind == bidi::kind::PDI)
> +-          cpp_warning_with_line (pfile, CPP_W_BIDIRECTIONAL, loc,
> 0,
> +-                                 "\"%s\" is closing an unopened
> context",
> +-                                 bidi::to_str (kind));
> ++          cpp_warning_at (pfile, CPP_W_BIDIRECTIONAL, &rich_loc,
> ++                          "\"%s\" is closing an unopened context",
> ++                          bidi::to_str (kind));
> +         else
> +-          cpp_warning_with_line (pfile, CPP_W_BIDIRECTIONAL, loc,
> 0,
> +-                                 "found problematic Unicode
> character \"%s\"",
> +-                                 bidi::to_str (kind));
> ++          cpp_warning_at (pfile, CPP_W_BIDIRECTIONAL, &rich_loc,
> ++                          "found problematic Unicode character
> \"%s\"",
> ++                          bidi::to_str (kind));
> +       }
> +     }
> +   /* We're done with this context.  */
> diff --git a/meta/recipes-devtools/gcc/gcc/0005-CVE-2021-42574.patch
> b/meta/recipes-devtools/gcc/gcc/0005-CVE-2021-42574.patch
> new file mode 100644
> index 0000000000..6e983a67b6
> --- /dev/null
> +++ b/meta/recipes-devtools/gcc/gcc/0005-CVE-2021-42574.patch
> @@ -0,0 +1,575 @@
> +From bef32d4a28595e933f24fef378cf052a30b674a7 Mon Sep 17 00:00:00
> 2001
> +From: David Malcolm <dmalcolm@redhat.com>
> +Date: Tue, 2 Nov 2021 15:45:22 -0400
> +Subject: [PATCH] libcpp: capture and underline ranges in -Wbidi-
> chars=
> + [PR103026]
> +MIME-Version: 1.0
> +Content-Type: text/plain; charset=utf8
> +Content-Transfer-Encoding: 8bit
> +
> +This patch converts the bidi::vec to use a struct so that we can
> +capture location_t values for the bidirectional control characters.
> +
> +Before:
> +
> +  Wbidi-chars-1.c: In function âmainâ:
> +  Wbidi-chars-1.c:6:43: warning: unpaired UTF-8 bidirectional
> control character detected [-Wbidi-chars=]
> +      6 |     /*<U+202E> } <U+2066>if (isAdmin)<U+2069> <U+2066>
> begin admins only */
> +
> |
>        ^
> +  Wbidi-chars-1.c:9:28: warning: unpaired UTF-8 bidirectional
> control character detected [-Wbidi-chars=]
> +      9 |     /* end admins only <U+202E> { <U+2066>*/
> +        |                                            ^
> +
> +After:
> +
> +  Wbidi-chars-1.c: In function âmainâ:
> +  Wbidi-chars-1.c:6:43: warning: unpaired UTF-8 bidirectional
> control characters detected [-Wbidi-chars=]
> +      6 |     /*<U+202E> } <U+2066>if (isAdmin)<U+2069> <U+2066>
> begin admins only */
> +        |       ~~~~~~~~
> ~~~~~~~~                    ^
> +        |       |
> |                           |
> +        |       |
> |                           end of bidirectional context
> +        |       U+202E (RIGHT-TO-LEFT OVERRIDE)         U+2066
> (LEFT-TO-RIGHT ISOLATE)
> +  Wbidi-chars-1.c:9:28: warning: unpaired UTF-8 bidirectional
> control characters detected [-Wbidi-chars=]
> +      9 |     /* end admins only <U+202E> { <U+2066>*/
> +        |                        ~~~~~~~~   ~~~~~~~~ ^
> +        |                        |          |        |
> +        |                        |          |        end of
> bidirectional context
> +        |                        |          U+2066 (LEFT-TO-RIGHT
> ISOLATE)
> +        |                        U+202E (RIGHT-TO-LEFT OVERRIDE)
> +
> +Signed-off-by: David Malcolm <dmalcolm@redhat.com>
> +
> +gcc/testsuite/ChangeLog:
> +       PR preprocessor/103026
> +       * c-c++-common/Wbidi-chars-ranges.c: New test.
> +
> +libcpp/ChangeLog:
> +       PR preprocessor/103026
> +       * lex.c (struct bidi::context): New.
> +       (bidi::vec): Convert to a vec of context rather than unsigned
> +       char.
> +       (bidi::ctx_at): Rename to...
> +       (bidi::pop_kind_at): ...this and reimplement for above
> change.
> +       (bidi::current_ctx): Update for change to vec.
> +       (bidi::current_ctx_ucn_p): Likewise.
> +       (bidi::current_ctx_loc): New.
> +       (bidi::on_char): Update for usage of context struct.  Add
> "loc"
> +       param and pass it when pushing contexts.
> +       (get_location_for_byte_range_in_cur_line): New.
> +       (get_bidi_utf8): Rename to...
> +       (get_bidi_utf8_1): ...this, reintroducing...
> +       (get_bidi_utf8): ...as a wrapper, setting *OUT when the
> result is
> +       not NONE.
> +       (get_bidi_ucn): Rename to...
> +       (get_bidi_ucn_1): ...this, reintroducing...
> +       (get_bidi_ucn): ...as a wrapper, setting *OUT when the result
> is
> +       not NONE.
> +       (class unpaired_bidi_rich_location): New.
> +       (maybe_warn_bidi_on_close): Use unpaired_bidi_rich_location
> when
> +       reporting on unpaired bidi chars.  Split into singular vs
> plural
> +       spellings.
> +       (maybe_warn_bidi_on_char): Pass in a location_t rather than a
> +       const uchar * and use it when emitting warnings, and when
> calling
> +       bidi::on_char.
> +       (_cpp_skip_block_comment): Capture location when kind is not
> NONE
> +       and pass it to maybe_warn_bidi_on_char.
> +       (skip_line_comment): Likewise.
> +       (forms_identifier_p): Likewise.
> +       (lex_raw_string): Likewise.
> +       (lex_string): Likewise.
> +
> +Signed-off-by: David Malcolm <dmalcolm@redhat.com>
> +
> +CVE: CVE-2021-42574
> +Upstream-Status: Backport
> [https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=bef32d4a28595e933f24f
> ef378cf052a30b674a7]
> +Signed-off-by: Pgowda <pgowda.cve@gmail.com>
> +
> +---
> + .../c-c++-common/Wbidi-chars-ranges.c         |  54 ++++
> + libcpp/lex.c                                  | 251 ++++++++++++++-
> ---
> + 2 files changed, 257 insertions(+), 48 deletions(-)
> + create mode 100644 gcc/testsuite/c-c++-common/Wbidi-chars-ranges.c
> +
> +diff --git a/gcc/testsuite/c-c++-common/Wbidi-chars-ranges.c
> b/gcc/testsuite/c-c++-common/Wbidi-chars-ranges.c
> +--- a/gcc/testsuite/c-c++-common/Wbidi-chars-ranges.c  1969-12-31
> 16:00:00.000000000 -0800
> ++++ b/gcc/testsuite/c-c++-common/Wbidi-chars-ranges.c  2021-12-25
> 01:39:55.116281847 -0800
> +@@ -0,0 +1,54 @@
> ++/* PR preprocessor/103026 */
> ++/* { dg-do compile } */
> ++/* { dg-options "-Wbidi-chars=unpaired -fdiagnostics-show-caret" }
> */
> ++/* Verify that we escape and underline pertinent bidirectional
> ++   control characters when quoting the source.  */
> ++
> ++int test_unpaired_bidi () {
> ++    int isAdmin = 0;
> ++    /*‮ } ⁦if (isAdmin)⁩ ⁦ begin admins only */
> ++/* { dg-warning "bidirectional" "" { target *-*-* } .-1 } */
> ++#if 0
> ++   { dg-begin-multiline-output "" }
> ++     /*<U+202E> } <U+2066>if (isAdmin)<U+2069> <U+2066> begin
> admins only */
> ++       ~~~~~~~~
> ~~~~~~~~                    ^
> ++       |
> |                           |
> ++       |
> |                           end of bidirectional context
> ++       U+202E (RIGHT-TO-LEFT OVERRIDE)         U+2066 (LEFT-TO-
> RIGHT ISOLATE)
> ++   { dg-end-multiline-output "" }
> ++#endif
> ++
> ++        __builtin_printf("You are an admin.\n");
> ++    /* end admins only ‮ { ⁦*/
> ++/* { dg-warning "bidirectional" "" { target *-*-* } .-1 } */
> ++#if 0
> ++   { dg-begin-multiline-output "" }
> ++     /* end admins only <U+202E> { <U+2066>*/
> ++                        ~~~~~~~~   ~~~~~~~~ ^
> ++                        |          |        |
> ++                        |          |        end of bidirectional
> context
> ++                        |          U+2066 (LEFT-TO-RIGHT ISOLATE)
> ++                        U+202E (RIGHT-TO-LEFT OVERRIDE)
> ++   { dg-end-multiline-output "" }
> ++#endif
> ++
> ++    return 0;
> ++}
> ++
> ++int LRE_‪_PDF_\u202c;
> ++/* { dg-warning "mismatch" "" { target *-*-* } .-1 } */
> ++#if 0
> ++   { dg-begin-multiline-output "" }
> ++ int LRE_<U+202A>_PDF_\u202c;
> ++         ~~~~~~~~     ^~~~~~
> ++   { dg-end-multiline-output "" }
> ++#endif
> ++
> ++const char *s1 = "LRE_‪_PDF_\u202c";
> ++/* { dg-warning "mismatch" "" { target *-*-* } .-1 } */
> ++#if 0
> ++   { dg-begin-multiline-output "" }
> ++ const char *s1 = "LRE_<U+202A>_PDF_\u202c";
> ++                       ~~~~~~~~     ^~~~~~
> ++   { dg-end-multiline-output "" }
> ++#endif
> +diff --git a/libcpp/lex.c b/libcpp/lex.c
> +--- a/libcpp/lex.c     2021-12-25 01:41:16.522868808 -0800
> ++++ b/libcpp/lex.c     2021-12-25 06:28:58.530680302 -0800
> +@@ -1172,11 +1172,34 @@ namespace bidi {
> +   /* All the UTF-8 encodings of bidi characters start with E2.  */
> +   constexpr uchar utf8_start = 0xe2;
> +
> ++  struct context
> ++  {
> ++    context () {}
> ++    context (location_t loc, kind k, bool pdf, bool ucn)
> ++    : m_loc (loc), m_kind (k), m_pdf (pdf), m_ucn (ucn)
> ++    {
> ++    }
> ++
> ++    kind get_pop_kind () const
> ++    {
> ++      return m_pdf ? kind::PDF : kind::PDI;
> ++    }
> ++    bool ucn_p () const
> ++    {
> ++      return m_ucn;
> ++    }
> ++
> ++    location_t m_loc;
> ++    kind m_kind;
> ++    unsigned m_pdf : 1;
> ++    unsigned m_ucn : 1;
> ++  };
> ++
> +   /* A vector holding currently open bidi contexts.  We use a char
> for
> +      each context, its LSB is 1 if it represents a PDF context, 0
> if it
> +      represents a PDI context.  The next bit is 1 if this context
> was open
> +      by a bidi character written as a UCN, and 0 when it was UTF-
> 8.  */
> +-  semi_embedded_vec <unsigned char, 16> vec;
> ++  semi_embedded_vec <context, 16> vec;
> +
> +   /* Close the whole comment/identifier/string literal/character
> constant
> +      context.  */
> +@@ -1193,19 +1216,19 @@ namespace bidi {
> +     vec.truncate (len - 1);
> +   }
> +
> +-  /* Return the context of the Ith element.  */
> +-  kind ctx_at (unsigned int i)
> ++  /* Return the pop kind of the context of the Ith element.  */
> ++  kind pop_kind_at (unsigned int i)
> +   {
> +-    return (vec[i] & 1) ? kind::PDF : kind::PDI;
> ++    return vec[i].get_pop_kind ();
> +   }
> +
> +-  /* Return which context is currently opened.  */
> ++  /* Return the pop kind of the context that is currently opened.
> */
> +   kind current_ctx ()
> +   {
> +     unsigned int len = vec.count ();
> +     if (len == 0)
> +       return kind::NONE;
> +-    return ctx_at (len - 1);
> ++    return vec[len - 1].get_pop_kind ();
> +   }
> +
> +   /* Return true if the current context comes from a UCN origin,
> that is,
> +@@ -1214,11 +1237,19 @@ namespace bidi {
> +   {
> +     unsigned int len = vec.count ();
> +     gcc_checking_assert (len > 0);
> +-    return (vec[len - 1] >> 1) & 1;
> ++    return vec[len - 1].m_ucn;
> +   }
> +
> +-  /* We've read a bidi char, update the current vector as
> necessary.  */
> +-  void on_char (kind k, bool ucn_p)
> ++  location_t current_ctx_loc ()
> ++  {
> ++    unsigned int len = vec.count ();
> ++    gcc_checking_assert (len > 0);
> ++    return vec[len - 1].m_loc;
> ++  }
> ++
> ++  /* We've read a bidi char, update the current vector as
> necessary.
> ++     LOC is only valid when K is not kind::NONE.  */
> ++  void on_char (kind k, bool ucn_p, location_t loc)
> +   {
> +     switch (k)
> +       {
> +@@ -1226,12 +1257,12 @@ namespace bidi {
> +       case kind::RLE:
> +       case kind::LRO:
> +       case kind::RLO:
> +-      vec.push (ucn_p ? 3u : 1u);
> ++      vec.push (context (loc, k, true, ucn_p));
> +       break;
> +       case kind::LRI:
> +       case kind::RLI:
> +       case kind::FSI:
> +-      vec.push (ucn_p ? 2u : 0u);
> ++      vec.push (context (loc, k, false, ucn_p));
> +       break;
> +       /* PDF terminates the scope of the last LRE, RLE, LRO, or RLO
> +        whose scope has not yet been terminated.  */
> +@@ -1245,7 +1276,7 @@ namespace bidi {
> +        yet been terminated.  */
> +       case kind::PDI:
> +       for (int i = vec.count () - 1; i >= 0; --i)
> +-        if (ctx_at (i) == kind::PDI)
> ++        if (pop_kind_at (i) == kind::PDI)
> +           {
> +             vec.truncate (i);
> +             break;
> +@@ -1295,10 +1326,47 @@ namespace bidi {
> +   }
> + }
> +
> ++/* Get location_t for the range of bytes [START, START + NUM_BYTES)
> ++   within the current line in FILE, with the caret at START.  */
> ++
> ++static location_t
> ++get_location_for_byte_range_in_cur_line (cpp_reader *pfile,
> ++                                       const unsigned char *const
> start,
> ++                                       size_t num_bytes)
> ++{
> ++  gcc_checking_assert (num_bytes > 0);
> ++
> ++  /* CPP_BUF_COLUMN and linemap_position_for_column both refer
> ++     to offsets in bytes, but CPP_BUF_COLUMN is 0-based,
> ++     whereas linemap_position_for_column is 1-based.  */
> ++
> ++  /* Get 0-based offsets within the line.  */
> ++  size_t start_offset = CPP_BUF_COLUMN (pfile->buffer, start);
> ++  size_t end_offset = start_offset + num_bytes - 1;
> ++
> ++  /* Now convert to location_t, where "columns" are 1-based byte
> offsets.  */
> ++  location_t start_loc = linemap_position_for_column (pfile-
> >line_table,
> ++                                                    start_offset +
> 1);
> ++  location_t end_loc = linemap_position_for_column (pfile-
> >line_table,
> ++                                                   end_offset + 1);
> ++
> ++  if (start_loc == end_loc)
> ++    return start_loc;
> ++
> ++  source_range src_range;
> ++  src_range.m_start = start_loc;
> ++  src_range.m_finish = end_loc;
> ++  location_t combined_loc = COMBINE_LOCATION_DATA (pfile-
> >line_table,
> ++                                                 start_loc,
> ++                                                 src_range,
> ++                                                 NULL);
> ++  return combined_loc;
> ++}
> ++
> + /* Parse a sequence of 3 bytes starting with P and return its bidi
> code.  */
> +
> + static bidi::kind
> +-get_bidi_utf8 (const unsigned char *const p)
> ++get_bidi_utf8_1 (const unsigned char *const p)
> + {
> +   gcc_checking_assert (p[0] == bidi::utf8_start);
> +
> +@@ -1340,10 +1408,25 @@ get_bidi_utf8 (const unsigned char *cons
> +   return bidi::kind::NONE;
> + }
> +
> ++/* Parse a sequence of 3 bytes starting with P and return its bidi
> code.
> ++   If the kind is not NONE, write the location to *OUT.*/
> ++
> ++static bidi::kind
> ++get_bidi_utf8 (cpp_reader *pfile, const unsigned char *const p,
> location_t *out)
> ++{
> ++  bidi::kind result = get_bidi_utf8_1 (p);
> ++  if (result != bidi::kind::NONE)
> ++    {
> ++      /* We have a sequence of 3 bytes starting at P.  */
> ++      *out = get_location_for_byte_range_in_cur_line (pfile, p, 3);
> ++    }
> ++  return result;
> ++}
> ++
> + /* Parse a UCN where P points just past \u or \U and return its
> bidi code.  */
> +
> + static bidi::kind
> +-get_bidi_ucn (const unsigned char *p, bool is_U)
> ++get_bidi_ucn_1 (const unsigned char *p, bool is_U)
> + {
> +   /* 6.4.3 Universal Character Names
> +       \u hex-quad
> +@@ -1412,6 +1495,62 @@ get_bidi_ucn (const unsigned char *p, bo
> +   return bidi::kind::NONE;
> + }
> +
> ++/* Parse a UCN where P points just past \u or \U and return its
> bidi code.
> ++   If the kind is not NONE, write the location to *OUT.*/
> ++
> ++static bidi::kind
> ++get_bidi_ucn (cpp_reader *pfile,  const unsigned char *p, bool
> is_U,
> ++            location_t *out)
> ++{
> ++  bidi::kind result = get_bidi_ucn_1 (p, is_U);
> ++  if (result != bidi::kind::NONE)
> ++    {
> ++      const unsigned char *start = p - 2;
> ++      size_t num_bytes = 2 + (is_U ? 8 : 4);
> ++      *out = get_location_for_byte_range_in_cur_line (pfile, start,
> num_bytes);
> ++    }
> ++  return result;
> ++}
> ++
> ++/* Subclass of rich_location for reporting on unpaired UTF-8
> ++   bidirectional control character(s).
> ++   Escape the source lines on output, and show all unclosed
> ++   bidi context, labelling everything.  */
> ++
> ++class unpaired_bidi_rich_location : public rich_location
> ++{
> ++ public:
> ++  class custom_range_label : public range_label
> ++  {
> ++   public:
> ++     label_text get_text (unsigned range_idx) const FINAL OVERRIDE
> ++     {
> ++       /* range 0 is the primary location; each subsequent range i
> + 1
> ++        is for bidi::vec[i].  */
> ++       if (range_idx > 0)
> ++       {
> ++         const bidi::context &ctxt (bidi::vec[range_idx - 1]);
> ++         return label_text::borrow (bidi::to_str (ctxt.m_kind));
> ++       }
> ++       else
> ++       return label_text::borrow (_("end of bidirectional
> context"));
> ++     }
> ++  };
> ++
> ++  unpaired_bidi_rich_location (cpp_reader *pfile, location_t loc)
> ++  : rich_location (pfile->line_table, loc, &m_custom_label)
> ++  {
> ++    set_escape_on_output (true);
> ++    for (unsigned i = 0; i < bidi::vec.count (); i++)
> ++      add_range (bidi::vec[i].m_loc,
> ++               SHOW_RANGE_WITHOUT_CARET,
> ++               &m_custom_label);
> ++  }
> ++
> ++ private:
> ++   custom_range_label m_custom_label;
> ++};
> ++
> + /* We're closing a bidi context, that is, we've encountered a
> newline,
> +    are closing a C-style comment, or are at the end of a string
> literal,
> +    character constant, or identifier.  Warn if this context was not
> +@@ -1427,11 +1566,17 @@ maybe_warn_bidi_on_close (cpp_reader *pf
> +       const location_t loc
> +       = linemap_position_for_column (pfile->line_table,
> +                                      CPP_BUF_COLUMN (pfile->buffer,
> p));
> +-      rich_location rich_loc (pfile->line_table, loc);
> +-      rich_loc.set_escape_on_output (true);
> +-      cpp_warning_at (pfile, CPP_W_BIDIRECTIONAL, &rich_loc,
> +-                    "unpaired UTF-8 bidirectional control character
> "
> +-                    "detected");
> ++      unpaired_bidi_rich_location rich_loc (pfile, loc);
> ++      /* cpp_callbacks doesn't yet have a way to handle singular vs
> plural
> ++       forms of a diagnostic, so fake it for now.  */
> ++      if (bidi::vec.count () > 1)
> ++      cpp_warning_at (pfile, CPP_W_BIDIRECTIONAL, &rich_loc,
> ++                      "unpaired UTF-8 bidirectional control
> characters "
> ++                      "detected");
> ++      else
> ++      cpp_warning_at (pfile, CPP_W_BIDIRECTIONAL, &rich_loc,
> ++                      "unpaired UTF-8 bidirectional control
> character "
> ++                      "detected");
> +     }
> +   /* We're done with this context.  */
> +   bidi::on_close ();
> +@@ -1439,12 +1584,13 @@ maybe_warn_bidi_on_close (cpp_reader *pf
> +
> + /* We're at the beginning or in the middle of an
> identifier/comment/string
> +    literal/character constant.  Warn if we've encountered a bidi
> character.
> +-   KIND says which bidi character it was; P points to it in the
> character
> +-   stream.  UCN_P is true iff this bidi character was written as a
> UCN.  */
> ++   KIND says which bidi control character it was; UCN_P is true iff
> this bidi
> ++   control character was written as a UCN.  LOC is the location of
> the
> ++   character, but is only valid if KIND != bidi::kind::NONE.  */
> +
> + static void
> +-maybe_warn_bidi_on_char (cpp_reader *pfile, const uchar *p,
> bidi::kind kind,
> +-                       bool ucn_p)
> ++maybe_warn_bidi_on_char (cpp_reader *pfile, bidi::kind kind,
> ++                       bool ucn_p, location_t loc)
> + {
> +   if (__builtin_expect (kind == bidi::kind::NONE, 1))
> +     return;
> +@@ -1453,9 +1599,6 @@ maybe_warn_bidi_on_char (cpp_reader *pfi
> +
> +   if (warn_bidi != bidirectional_none)
> +     {
> +-      const location_t loc
> +-      = linemap_position_for_column (pfile->line_table,
> +-                                     CPP_BUF_COLUMN (pfile->buffer,
> p));
> +       rich_location rich_loc (pfile->line_table, loc);
> +       rich_loc.set_escape_on_output (true);
> +
> +@@ -1467,9 +1610,12 @@ maybe_warn_bidi_on_char (cpp_reader *pfi
> +       {
> +         if (warn_bidi == bidirectional_unpaired
> +             && bidi::current_ctx_ucn_p () != ucn_p)
> +-          cpp_warning_at (pfile, CPP_W_BIDIRECTIONAL, &rich_loc,
> +-                          "UTF-8 vs UCN mismatch when closing "
> +-                          "a context by \"%s\"", bidi::to_str
> (kind));
> ++          {
> ++            rich_loc.add_range (bidi::current_ctx_loc ());
> ++            cpp_warning_at (pfile, CPP_W_BIDIRECTIONAL, &rich_loc,
> ++                            "UTF-8 vs UCN mismatch when closing "
> ++                            "a context by \"%s\"", bidi::to_str
> (kind));
> ++          }
> +       }
> +       else if (warn_bidi == bidirectional_any)
> +       {
> +@@ -1484,7 +1630,7 @@ maybe_warn_bidi_on_char (cpp_reader *pfi
> +       }
> +     }
> +   /* We're done with this context.  */
> +-  bidi::on_char (kind, ucn_p);
> ++  bidi::on_char (kind, ucn_p, loc);
> + }
> +
> + /* Skip a C-style block comment.  We find the end of the comment by
> +@@ -1552,8 +1698,9 @@ _cpp_skip_block_comment (cpp_reader *pfi
> +        a bidirectional control character.  */
> +       else if (__builtin_expect (c == bidi::utf8_start, 0) &&
> warn_bidi_p)
> +       {
> +-        bidi::kind kind = get_bidi_utf8 (cur - 1);
> +-        maybe_warn_bidi_on_char (pfile, cur, kind,
> /*ucn_p=*/false);
> ++        location_t loc;
> ++        bidi::kind kind = get_bidi_utf8 (pfile, cur - 1, &loc);
> ++        maybe_warn_bidi_on_char (pfile, kind, /*ucn_p=*/false,
> loc);
> +       }
> +     }
> +
> +@@ -1586,9 +1733,9 @@ skip_line_comment (cpp_reader *pfile)
> +           {
> +             if (__builtin_expect (*buffer->cur == bidi::utf8_start,
> 0))
> +               {
> +-                bidi::kind kind = get_bidi_utf8 (buffer->cur);
> +-                maybe_warn_bidi_on_char (pfile, buffer->cur, kind,
> +-                                         /*ucn_p=*/false);
> ++                location_t loc;
> ++                bidi::kind kind = get_bidi_utf8 (pfile, buffer-
> >cur, &loc);
> ++                maybe_warn_bidi_on_char (pfile, kind,
> /*ucn_p=*/false, loc);
> +               }
> +             buffer->cur++;
> +           }
> +@@ -1734,9 +1881,9 @@ forms_identifier_p (cpp_reader *pfile, i
> +         if (__builtin_expect (*buffer->cur == bidi::utf8_start, 0)
> +             && warn_bidi_p)
> +           {
> +-            bidi::kind kind = get_bidi_utf8 (buffer->cur);
> +-            maybe_warn_bidi_on_char (pfile, buffer->cur, kind,
> +-                                     /*ucn_p=*/false);
> ++            location_t loc;
> ++            bidi::kind kind = get_bidi_utf8 (pfile, buffer->cur,
> &loc);
> ++            maybe_warn_bidi_on_char (pfile, kind, /*ucn_p=*/false,
> loc);
> +           }
> +         if (_cpp_valid_utf8 (pfile, &buffer->cur, buffer->rlimit, 1
> + !first,
> +                              state, &s))
> +@@ -1748,10 +1895,12 @@ forms_identifier_p (cpp_reader *pfile, i
> +         buffer->cur += 2;
> +         if (warn_bidi_p)
> +           {
> +-            bidi::kind kind = get_bidi_ucn (buffer->cur,
> +-                                            buffer->cur[-1] ==
> 'U');
> +-            maybe_warn_bidi_on_char (pfile, buffer->cur, kind,
> +-                                     /*ucn_p=*/true);
> ++            location_t loc;
> ++            bidi::kind kind = get_bidi_ucn (pfile,
> ++                                            buffer->cur,
> ++                                            buffer->cur[-1] == 'U',
> ++                                            &loc);
> ++            maybe_warn_bidi_on_char (pfile, kind, /*ucn_p=*/true,
> loc);
> +           }
> +         if (_cpp_valid_ucn (pfile, &buffer->cur, buffer->rlimit, 1
> + !first,
> +                             state, &s, NULL, NULL))
> +@@ -2327,12 +2476,15 @@ lex_raw_string (cpp_reader *pfile, cpp_t
> +       }
> +       else if (__builtin_expect ((unsigned char) c ==
> bidi::utf8_start, 0)
> +              && warn_bidi_p)
> +-      maybe_warn_bidi_on_char (pfile, pos - 1, get_bidi_utf8 (pos -
> 1),
> +-                               /*ucn_p=*/false);
> ++      {
> ++        location_t loc;
> ++        bidi::kind kind = get_bidi_utf8 (pfile, cur - 1, &loc);
> ++        maybe_warn_bidi_on_char (pfile, kind, /*ucn_p=*/false,
> loc);
> ++      }
> +     }
> +
> +   if (warn_bidi_p)
> +-    maybe_warn_bidi_on_close (pfile, pos);
> ++    maybe_warn_bidi_on_close (pfile, cur);
> +
> +   if (CPP_OPTION (pfile, user_literals))
> +     {
> +@@ -2438,8 +2590,10 @@ lex_string (cpp_reader *pfile, cpp_token
> +       {
> +         if ((cur[0] == 'u' || cur[0] == 'U') && warn_bidi_p)
> +           {
> +-            bidi::kind kind = get_bidi_ucn (cur + 1, cur[0] ==
> 'U');
> +-            maybe_warn_bidi_on_char (pfile, cur, kind,
> /*ucn_p=*/true);
> ++            location_t loc;
> ++            bidi::kind kind = get_bidi_ucn (pfile, cur + 1, cur[0]
> == 'U',
> ++                                            &loc);
> ++            maybe_warn_bidi_on_char (pfile, kind, /*ucn_p=*/true,
> loc);
> +           }
> +         cur++;
> +       }
> +@@ -2467,8 +2621,9 @@ lex_string (cpp_reader *pfile, cpp_token
> +       saw_NUL = true;
> +       else if (__builtin_expect (c == bidi::utf8_start, 0) &&
> warn_bidi_p)
> +       {
> +-        bidi::kind kind = get_bidi_utf8 (cur - 1);
> +-        maybe_warn_bidi_on_char (pfile, cur - 1, kind,
> /*ucn_p=*/false);
> ++        location_t loc;
> ++        bidi::kind kind = get_bidi_utf8 (pfile, cur - 1, &loc);
> ++        maybe_warn_bidi_on_char (pfile, kind, /*ucn_p=*/false,
> loc);
> +       }
> +     }
> +