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authorAlexey Neyman <stilor@att.net>2017-02-08 16:00:57 -0200
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2017-03-12 17:29:32 -0300
commitd40dbe722f004f999b589de776f7e57e564dda01 (patch)
tree51eb85e0bdbb58f11d0275b58e7e46b6303ba065 /sysdeps/sh
parentcb09a3d49742aa4b8e541334e2e49e8cb9b652e2 (diff)
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sh: Fix building with gcc5/6
Build glibc for sh4-unknown-linux-gnu currently fails if one's
using GCC5/6: in dl-conflict.c, the elf_machine_rela() function
is called with NULL as its 3rd argument, sym. The implementation
of that function in sysdeps/sh/dl-machine.h dereferences that pointer:

const Elf32_Sym *const refsym = sym;
...
if (map == &GL(dl_rtld_map))
  value -= map->l_addr + refsym->st_value + reloc->r_addend;

GCC discovers a null pointer dereference, and in accordance with
-fdelete-null-pointer-checks (which is enabled in -O2) replaces this
code with a trap - which, as SH does not implement a trap pattern in
GCC, evaluates to an abort() call. This abort() call pulls many more
objects from libc_nonshared.a, eventually resulting in link failure
due to multiple definitions for a number of symbols.

As far as I see, the conditional before this code is always false in
rtld: _dl_resolve_conflicts() is called with main_map as the first
argument, not GL(_dl_rtld_map), but since that call is in yet another
compilation unit, GCC does not know about it. Patch that wraps this
conditional into !defined RESOLVE_CONFLICT_FIND_MAP attached.

	* sysdeps/sh/dl-machine.h (elf_machine_rela): The condition
	in R_SH_DIR32 case is always false when inlined from
	dl-conflict.c. Ifdef out to prevent GCC from insertin an
	abort() call.
Diffstat (limited to 'sysdeps/sh')
-rw-r--r--sysdeps/sh/dl-machine.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/sysdeps/sh/dl-machine.h b/sysdeps/sh/dl-machine.h
index 449deea6fe..2b468af6fa 100644
--- a/sysdeps/sh/dl-machine.h
+++ b/sysdeps/sh/dl-machine.h
@@ -389,7 +389,7 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc,
 	  break;
 	case R_SH_DIR32:
 	  {
-#ifndef RTLD_BOOTSTRAP
+#if !defined RTLD_BOOTSTRAP && !defined RESOLVE_CONFLICT_FIND_MAP
 	   /* This is defined in rtld.c, but nowhere in the static
 	      libc.a; make the reference weak so static programs can
 	      still link.  This declaration cannot be done when