[Buildroot] [RFC][PATCH] bfin: fix two issues with internal toolchain

[Waldemar Brodkorb <wbx@openadk.org>]

Hi,
Waldemar Brodkorb wrote,

I think the patch is okay and should be used. But I give up on the
remaining problem for this release. 

I tried all version of binutils from 2.27 down to ADI toolchain
binutils 2.21. It seems not a binutils or linker problem.

I tried to convert the LOCAL symbols with objcopy to GLOBAL, but
the problem persist.

I recognized that the missing symbols in libstdc++.so are NOTYPE,
but in the working external toolchain they are FUNC.

Without help from some Blackfin developer from Analog Devices I see
no chance to fix it right now.

@Thomas: Can you disable C++ for internal Blackfin toolchain?
Thanks.

best regards
 Waldemar

> Allows to compile DWARF EH.
> 
> Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>
> ---
> Hi,
> this is my present work on the Blackfin C++ issues with the internal
> toolchain. There is still following problem:
> $ ./output/host/usr/bin/bfin-buildroot-linux-uclibc-g++ -o foo foo.cc                                                                                                              
> /home/wbx/buildroot/output/host/usr/lib/gcc/bfin-buildroot-linux-uclibc/6.1.0/../../../../bfin-buildroot-linux-uclibc/lib/libstdc++.so:
> undefined reference to `_Unwind_GetRegionStart'
> ..
> $ cat foo.cc                                                                                                                                                                       
> #include <iostream>
> int main(void) { std::cout << "hello, world\n"; }
> 
> But libstdc++ should search for __Unwind_GetRegionStart:
> nm
> /home/wbx/buildroot/output/host/usr/lib/gcc/bfin-buildroot-linux-uclibc/6.1.0/../../../../bfin-buildroot-linux-uclibc/lib/libstdc++.so|grep
> _Unwind_GetRegionStart<
>          U __Unwind_GetRegionStart
> 
> And libgcc_s.so.1 provides it:
> ./output/host/usr/bin/bfin-buildroot-linux-uclibc-nm
> ./output/host/usr/bfin-buildroot-linux-uclibc/sysroot/lib/libgcc_s.so.1|grep
> _Unwind_GetRegionStart                         
> 00005d0c t __Unwind_GetRegionStart
> 
> So why is ld trying to find _Unwind_GetRegionStart instead of
> __Unwind_GetRegionStart when linking?
> Does ld ignores __USER_LABEL_PREFIX__?
> 
> Any ideas and help is really appreciated.
> 
> Here are some g++ verbose output logs from internal and external
> buildroot toolchain:
> http://debug.openadk.org/buildroot/
> 
> ---
>  package/gcc/6.1.0/892-disable-dwarf-bfin.patch     |   24 -------------
>  package/gcc/6.1.0/892-fix-dwarf-fdpic.patch        |   37 ++++++++++++++++++++
>  .../6.1.0/893-bfin-add-libgcc-linker-script.patch  |   20 +++++++++++
>  3 files changed, 57 insertions(+), 24 deletions(-)
>  delete mode 100644 package/gcc/6.1.0/892-disable-dwarf-bfin.patch
>  create mode 100644 package/gcc/6.1.0/892-fix-dwarf-fdpic.patch
>  create mode 100644 package/gcc/6.1.0/893-bfin-add-libgcc-linker-script.patch
> 
> diff --git a/package/gcc/6.1.0/892-disable-dwarf-bfin.patch b/package/gcc/6.1.0/892-disable-dwarf-bfin.patch
> deleted file mode 100644
> index ebd31a1..0000000
> --- a/package/gcc/6.1.0/892-disable-dwarf-bfin.patch
> +++ /dev/null
> @@ -1,24 +0,0 @@
> -Dwarf support does not compile on Blackfin
> -
> -Reported upstream:
> -https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68468
> -
> -Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>
> -
> -diff -Nur gcc-6.1.0.orig/libgcc/config.host gcc-6.1.0/libgcc/config.host
> ---- gcc-6.1.0.orig/libgcc/config.host	2016-02-26 21:02:28.000000000 +0100
> -+++ gcc-6.1.0/libgcc/config.host	2016-05-12 19:26:30.973350274 +0200
> -@@ -230,6 +230,13 @@
> -       ;;
> -   esac
> -   ;;
> -+bfin-*-*linux*)
> -+  tmake_file="$tmake_file t-crtstuff-pic t-libgcc-pic t-slibgcc t-slibgcc-gld t-slibgcc-elf-ver t-linux"
> -+  extra_parts="crtbegin.o crtbeginS.o crtbeginT.o crtend.o crtendS.o"
> -+  if test x$enable_vtable_verify = xyes; then
> -+    extra_parts="$extra_parts vtv_start.o vtv_end.o vtv_start_preinit.o vtv_end_preinit.o"
> -+  fi
> -+  ;;
> - *-*-linux* | frv-*-*linux* | *-*-kfreebsd*-gnu | *-*-knetbsd*-gnu | *-*-gnu* | *-*-kopensolaris*-gnu)
> -   tmake_file="$tmake_file t-crtstuff-pic t-libgcc-pic t-eh-dw2-dip t-slibgcc t-slibgcc-gld t-slibgcc-elf-ver t-linux"
> -   extra_parts="crtbegin.o crtbeginS.o crtbeginT.o crtend.o crtendS.o"
> diff --git a/package/gcc/6.1.0/892-fix-dwarf-fdpic.patch b/package/gcc/6.1.0/892-fix-dwarf-fdpic.patch
> new file mode 100644
> index 0000000..315b406
> --- /dev/null
> +++ b/package/gcc/6.1.0/892-fix-dwarf-fdpic.patch
> @@ -0,0 +1,37 @@
> +Fix DWARF compilation for FDPIC targets
> +
> +Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>
> +
> +diff -Nur gcc-6.1.0.orig/libgcc/unwind-dw2-fde-dip.c gcc-6.1.0/libgcc/unwind-dw2-fde-dip.c
> +--- gcc-6.1.0.orig/libgcc/unwind-dw2-fde-dip.c	2016-01-04 15:30:50.000000000 +0100
> ++++ gcc-6.1.0/libgcc/unwind-dw2-fde-dip.c	2016-08-05 02:17:40.424195128 +0200
> +@@ -124,7 +124,11 @@
> + {
> +   _Unwind_Ptr pc_low;
> +   _Unwind_Ptr pc_high;
> ++#if defined __FRV_FDPIC__ || defined __BFIN_FDPIC__
> ++  struct elf32_fdpic_loadaddr load_base;
> ++#else
> +   _Unwind_Ptr load_base;
> ++#endif
> +   const ElfW(Phdr) *p_eh_frame_hdr;
> +   const ElfW(Phdr) *p_dynamic;
> +   struct frame_hdr_cache_element *link;
> +@@ -163,7 +167,7 @@
> +   struct unw_eh_callback_data *data = (struct unw_eh_callback_data *) ptr;
> +   const ElfW(Phdr) *phdr, *p_eh_frame_hdr, *p_dynamic;
> +   long n, match;
> +-#ifdef __FRV_FDPIC__
> ++#if defined __FRV_FDPIC__ || defined __BFIN_FDPIC__
> +   struct elf32_fdpic_loadaddr load_base;
> + #else
> +   _Unwind_Ptr load_base;
> +@@ -347,7 +351,7 @@
> + 	    break;
> + 	  }
> +     }
> +-# elif defined __FRV_FDPIC__ && defined __linux__
> ++# elif (defined __FRV_FDPIC__ || defined __BFIN_FDPIC__) && defined __linux__
> +   data->dbase = load_base.got_value;
> + # else
> + #  error What is DW_EH_PE_datarel base on this platform?
> diff --git a/package/gcc/6.1.0/893-bfin-add-libgcc-linker-script.patch b/package/gcc/6.1.0/893-bfin-add-libgcc-linker-script.patch
> new file mode 100644
> index 0000000..88548fc
> --- /dev/null
> +++ b/package/gcc/6.1.0/893-bfin-add-libgcc-linker-script.patch
> @@ -0,0 +1,20 @@
> +Add libgcc linker script for Blackfin FDPIC.
> +
> +Solves following linking error:
> +# bfin-openadk-linux-uclibc-g++ -o foo t.c
> +bfin-openadk-linux-uclibc/bin/ld: foo: hidden symbol `___udivsi3' in libgcc.a(_udivsi3.o) is referenced by DSO
> +
> +Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>
> +
> +diff -Nur gcc-6.1.0.orig/libgcc/config.host gcc-6.1.0/libgcc/config.host
> +--- gcc-6.1.0.orig/libgcc/config.host	2016-02-26 21:02:28.000000000 +0100
> ++++ gcc-6.1.0/libgcc/config.host	2016-07-25 02:47:05.818797217 +0200
> +@@ -444,7 +444,7 @@
> + 	md_unwind_header=bfin/linux-unwind.h
> +         ;;
> + bfin*-linux-uclibc*)
> +-	tmake_file="$tmake_file bfin/t-bfin bfin/t-crtstuff t-libgcc-pic t-fdpbit bfin/t-linux"
> ++	tmake_file="$tmake_file bfin/t-bfin bfin/t-crtstuff t-libgcc-pic t-slibgcc-libgcc t-fdpbit bfin/t-linux"
> + 	# No need to build crtbeginT.o on uClibc systems.  Should probably
> + 	# be moved to the OS specific section above.
> + 	extra_parts="crtbegin.o crtbeginS.o crtend.o crtendS.o"
> -- 
> 1.7.10.4
> 
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