On 09/05/15 19:57, Szabolcs Nagy wrote:
> * H.J. Lu <hjl.to...@gmail.com> [2015-05-09 10:41:41 -0700]:
>> There are
>>
>> 4: 0000000000002b70 806 FUNC GLOBAL DEFAULT 12
>> __cpu_indicator_init@GCC_4.8.0
>> 38: 00000000002153d0 16 OBJECT GLOBAL DEFAULT 25
>> __cpu_model@GCC_4.8.0
>>
>> and
>>
>> 000000000215000 0000000400000001 R_X86_64_64
>> 0000000000002b70 __cpu_indicator_init@GCC_4.8.0 + 0
>> 0000000000215220 0000002600000006 R_X86_64_GLOB_DAT
>> 00000000002153d0 __cpu_model@GCC_4.8.0 + 0
>>
>> in libgcc_s.so.1. Musl ld.so must be fixed to handle it.
>>
Rich is looking at how to do this non-intrusively, but
it seems non-trivial (some users of musl prefer not to
resolve such versioned symbols).
>
> i think it might be enough to add __cpu_indicator_init_local
> as an alias to __cpu_indicator_init in libgcc.a and then use
> the *_local symbol from the ifunc resolver, that way no new
> dependency is added to libgcc_s.so handling.
i tried this approach and it seems to work: passes all
multiversioning tests on x86_64.
i think it's no worse than the symver approach.
is it ok to change the current fix to this?
libgcc/Changelog:
2015-05-11 Szabolcs Nagy <szabolcs.n...@arm.com>
* config/i386/cpuinfo.c (__cpu_indicator_init_local): Add.
(__cpu_indicator_init@GCC_4.8.0, __cpu_model@GCC_4.8.0): Remove.
* config/i386/t-linux (HOST_LIBGCC2_CFLAGS): Remove -DUSE_ELF_SYMVER.
gcc/Changelog:
2015-05-11 Szabolcs Nagy <szabolcs.n...@arm.com>
* config/i386/i386.c (ix86_expand_builtin): Make __builtin_cpu_init
call __cpu_indicator_init_local instead of __cpu_indicator_init.
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 7bd9ff3..7327cf3 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -38398,10 +38398,10 @@ ix86_expand_builtin (tree exp, rtx target, rtx subtarget,
{
case IX86_BUILTIN_CPU_INIT:
{
- /* Make it call __cpu_indicator_init in libgcc. */
+ /* Make it call __cpu_indicator_init_local in libgcc.a. */
tree call_expr, fndecl, type;
type = build_function_type_list (integer_type_node, NULL_TREE);
- fndecl = build_fn_decl ("__cpu_indicator_init", type);
+ fndecl = build_fn_decl ("__cpu_indicator_init_local", type);
call_expr = build_call_expr (fndecl, 0);
return expand_expr (call_expr, target, mode, EXPAND_NORMAL);
}
diff --git a/libgcc/config/i386/cpuinfo.c b/libgcc/config/i386/cpuinfo.c
index f6f91dd..86b6d21 100644
--- a/libgcc/config/i386/cpuinfo.c
+++ b/libgcc/config/i386/cpuinfo.c
@@ -425,7 +425,7 @@ __cpu_indicator_init (void)
return 0;
}
-#if defined SHARED && defined USE_ELF_SYMVER
-__asm__ (".symver __cpu_indicator_init, __cpu_indicator_init@GCC_4.8.0");
-__asm__ (".symver __cpu_model, __cpu_model@GCC_4.8.0");
+#ifndef SHARED
+int __cpu_indicator_init_local (void)
+ __attribute__ ((weak, alias ("__cpu_indicator_init")));
#endif
diff --git a/libgcc/config/i386/t-linux b/libgcc/config/i386/t-linux
index 11bb46e..4f47f7b 100644
--- a/libgcc/config/i386/t-linux
+++ b/libgcc/config/i386/t-linux
@@ -3,4 +3,4 @@
# t-slibgcc-elf-ver and t-linux
SHLIB_MAPFILES = libgcc-std.ver $(srcdir)/config/i386/libgcc-glibc.ver
-HOST_LIBGCC2_CFLAGS += -mlong-double-80 -DUSE_ELF_SYMVER
+HOST_LIBGCC2_CFLAGS += -mlong-double-80
