[Buildroot] [PATCH v2 01/15] package/glibc/arc: fix build issue with gcc-9.1

[Romain Naour <romain.naour@gmail.com>]

Backport from upstream [1] to fix build issue with glibc arc-2018.09-release
(based on glibc 2.28) and gcc 9.1 [2]]

Using glibc arc-2.29-2019.02.08 or the upcoming arc-2019.03 release include
this patch.

The upstream patch [1] modify mostly x86_64 files, but also two generic headers
where the new __attribute_copy__() macro is defined *and* used to complement
existing attribute-related macros.

So, it is not much the x86_64 part we're interested in, but the generic
two headers, which changes percolate to the various functions via the
various attribute macros...

[1] https://sourceware.org/git/?p=glibc.git;a=commit;h=1626a1cfcd6ba1cc64721be1036c2873211d499b
[2] https://gitlab.com/kubu93/toolchains-builder/-/jobs/205435682

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Cc: Alexey Brodkin <alexey.brodkin@synopsys.com>
Cc: Evgeniy Didin <Evgeniy.Didin@synopsys.com>
Cc: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
---
v2: remove x86_64 part of the backported patch (Yann).
    commit log (Yann)
---
 ...0001-Add-support-for-GCC-9-attribute-copy.patch | 160 +++++++++++++++++++++
 1 file changed, 160 insertions(+)
 create mode 100644 package/glibc/arc-2018.09-release/0001-Add-support-for-GCC-9-attribute-copy.patch

diff --git a/package/glibc/arc-2018.09-release/0001-Add-support-for-GCC-9-attribute-copy.patch b/package/glibc/arc-2018.09-release/0001-Add-support-for-GCC-9-attribute-copy.patch
new file mode 100644
index 0000000000..0c0a8a9337
--- /dev/null
+++ b/package/glibc/arc-2018.09-release/0001-Add-support-for-GCC-9-attribute-copy.patch
@@ -0,0 +1,160 @@
+From 3e0c7985c9535304d87af3ad728f5f6d34557f0d Mon Sep 17 00:00:00 2001
+From: Martin Sebor <msebor@redhat.com>
+Date: Fri, 9 Nov 2018 17:24:12 -0700
+Subject: [PATCH] Add support for GCC 9 attribute copy.
+
+GCC 9 has gained an enhancement to help detect attribute mismatches
+between alias declarations and their targets.  It consists of a new
+warning, -Wattribute-alias, an enhancement to an existing warning,
+-Wmissing-attributes, and a new attribute called copy.
+
+The purpose of the warnings is to help identify either possible bugs
+(an alias declared with more restrictive attributes than its target
+promises) or optimization or diagnostic opportunities (an alias target
+missing some attributes that it could be declared with that might
+benefit analysis and code generation).  The purpose of the new
+attribute is to easily apply (almost) the same set of attributes
+to one declaration as those already present on another.
+
+As expected (and intended) the enhancement triggers warnings for
+many alias declarations in Glibc code.  This change, tested on
+x86_64-linux, avoids all instances of the new warnings by making
+use of the attribute where appropriate.  To fully benefit from
+the enhancement Glibc will need to be compiled with
+ -Wattribute-alias=2 and remaining warnings reviewed and dealt with
+(there are a couple of thousand but most should be straightforward
+to deal with).
+
+ChangeLog:
+
+	* include/libc-symbols.h (__attribute_copy__): Define macro unless
+	it's already defined.
+	(_strong_alias): Use __attribute_copy__.
+	(_weak_alias,  __hidden_ver1,  __hidden_nolink2): Same.
+	* misc/sys/cdefs.h (__attribute_copy__): New macro.
+	* sysdeps/x86_64/multiarch/memchr.c (memchr): Use __attribute_copy__.
+	* sysdeps/x86_64/multiarch/memcmp.c (memcmp): Same.
+	* sysdeps/x86_64/multiarch/mempcpy.c (mempcpy): Same.
+	* sysdeps/x86_64/multiarch/memset.c (memset): Same.
+	* sysdeps/x86_64/multiarch/stpcpy.c (stpcpy): Same.
+	* sysdeps/x86_64/multiarch/strcat.c (strcat): Same.
+	* sysdeps/x86_64/multiarch/strchr.c (strchr): Same.
+	* sysdeps/x86_64/multiarch/strcmp.c (strcmp): Same.
+	* sysdeps/x86_64/multiarch/strcpy.c (strcpy): Same.
+	* sysdeps/x86_64/multiarch/strcspn.c (strcspn): Same.
+	* sysdeps/x86_64/multiarch/strlen.c (strlen): Same.
+	* sysdeps/x86_64/multiarch/strncmp.c (strncmp): Same.
+	* sysdeps/x86_64/multiarch/strncpy.c (strncpy): Same.
+	* sysdeps/x86_64/multiarch/strnlen.c (strnlen): Same.
+	* sysdeps/x86_64/multiarch/strpbrk.c (strpbrk): Same.
+	* sysdeps/x86_64/multiarch/strrchr.c (strrchr): Same.
+	* sysdeps/x86_64/multiarch/strspn.c (strspn): Same.
+
+Using glibc arc-2.29-2019.02.08 or the upcoming arc-2019.03 release include this patch.
+
+[1] https://sourceware.org/git/?p=glibc.git;a=commit;h=1626a1cfcd6ba1cc64721be1036c2873211d499b
+[2] https://gitlab.com/kubu93/toolchains-builder/-/jobs/205435682
+
+Signed-off-by: Romain Naour <romain.naour@gmail.com>
+[Romain:
+    - Backport from upstream [1] to fix build issue with glibc arc-2018.09-release
+      (based on glibc 2.28) and gcc 9.1 [2]
+    - Also drop the x86-64 related hunks to avoid confusion.
+]
+Cc: Alexey Brodkin <alexey.brodkin@synopsys.com>
+Cc: Evgeniy Didin <Evgeniy.Didin@synopsys.com>
+Cc: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
+---
+ include/libc-symbols.h | 20 +++++++++++++++-----
+ misc/sys/cdefs.h       | 10 ++++++++++
+ 2 files changed, 25 insertions(+), 5 deletions(-)
+
+diff --git a/include/libc-symbols.h b/include/libc-symbols.h
+index 8b9273c13a..e71a479e84 100644
+--- a/include/libc-symbols.h
++++ b/include/libc-symbols.h
+@@ -125,6 +125,11 @@
+ # define ASM_LINE_SEP ;
+ #endif
+ 
++#ifndef __attribute_copy__
++/* Provide an empty definition when cdefs.h is not included.  */
++# define __attribute_copy__(arg)
++#endif
++
+ #ifndef __ASSEMBLER__
+ /* GCC understands weak symbols and aliases; use its interface where
+    possible, instead of embedded assembly language.  */
+@@ -132,7 +137,8 @@
+ /* Define ALIASNAME as a strong alias for NAME.  */
+ # define strong_alias(name, aliasname) _strong_alias(name, aliasname)
+ # define _strong_alias(name, aliasname) \
+-  extern __typeof (name) aliasname __attribute__ ((alias (#name)));
++  extern __typeof (name) aliasname __attribute__ ((alias (#name))) \
++    __attribute_copy__ (name);
+ 
+ /* This comes between the return type and function name in
+    a function definition to make that definition weak.  */
+@@ -143,14 +149,16 @@
+    If weak aliases are not available, this defines a strong alias.  */
+ # define weak_alias(name, aliasname) _weak_alias (name, aliasname)
+ # define _weak_alias(name, aliasname) \
+-  extern __typeof (name) aliasname __attribute__ ((weak, alias (#name)));
++  extern __typeof (name) aliasname __attribute__ ((weak, alias (#name))) \
++    __attribute_copy__ (name);
+ 
+ /* Same as WEAK_ALIAS, but mark symbol as hidden.  */
+ # define weak_hidden_alias(name, aliasname) \
+   _weak_hidden_alias (name, aliasname)
+ # define _weak_hidden_alias(name, aliasname) \
+   extern __typeof (name) aliasname \
+-    __attribute__ ((weak, alias (#name), __visibility__ ("hidden")));
++    __attribute__ ((weak, alias (#name), __visibility__ ("hidden"))) \
++    __attribute_copy__ (name);
+ 
+ /* Declare SYMBOL as weak undefined symbol (resolved to 0 if not defined).  */
+ # define weak_extern(symbol) _weak_extern (weak symbol)
+@@ -532,7 +540,8 @@ for linking")
+ #  define __hidden_ver1(local, internal, name) \
+   extern __typeof (name) __EI_##name __asm__(__hidden_asmname (#internal)); \
+   extern __typeof (name) __EI_##name \
+-	__attribute__((alias (__hidden_asmname (#local))))
++    __attribute__((alias (__hidden_asmname (#local))))	\
++    __attribute_copy__ (name)
+ #  define hidden_ver(local, name)	__hidden_ver1(local, __GI_##name, name);
+ #  define hidden_data_ver(local, name)	hidden_ver(local, name)
+ #  define hidden_def(name)		__hidden_ver1(__GI_##name, name, name);
+@@ -545,7 +554,8 @@ for linking")
+ #  define __hidden_nolink1(local, internal, name, version) \
+   __hidden_nolink2 (local, internal, name, version)
+ #  define __hidden_nolink2(local, internal, name, version) \
+-  extern __typeof (name) internal __attribute__ ((alias (#local))); \
++  extern __typeof (name) internal __attribute__ ((alias (#local)))	\
++    __attribute_copy__ (name);						\
+   __hidden_nolink3 (local, internal, #name "@" #version)
+ #  define __hidden_nolink3(local, internal, vername) \
+   __asm__ (".symver " #internal ", " vername);
+diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
+index 3f6fe3cc85..8d585680a6 100644
+--- a/misc/sys/cdefs.h
++++ b/misc/sys/cdefs.h
+@@ -431,6 +431,16 @@
+ # define __attribute_nonstring__
+ #endif
+ 
++/* Undefine (also defined in libc-symbols.h).  */
++#undef __attribute_copy__
++#if __GNUC_PREREQ (9, 0)
++/* Copies attributes from the declaration or type referenced by
++   the argument.  */
++# define __attribute_copy__(arg) __attribute__ ((__copy__ (arg)))
++#else
++# define __attribute_copy__(arg)
++#endif
++
+ #if (!defined _Static_assert && !defined __cplusplus \
+      && (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) < 201112 \
+      && (!__GNUC_PREREQ (4, 6) || defined __STRICT_ANSI__))
+-- 
+2.14.5
+
-- 
2.14.5