On Mon, Mar 30, 2015 at 10:38 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Mon, Mar 30, 2015 at 07:08:00PM -0700, H.J. Lu wrote:
>> --- a/gcc/gcc.c
>> +++ b/gcc/gcc.c
>> @@ -1566,11 +1566,13 @@ init_spec (void)
>>       if (in_sep && *p == '-' && strncmp (p, "-lgcc", 5) == 0)
>>         {
>>           init_gcc_specs (&obstack,
>> +                         "-lgcc_nonshared "
>>                           "-lgcc_s"
>>  #ifdef USE_LIBUNWIND_EXCEPTIONS
>>                           " -lunwind"
>>  #endif
>>                           ,
>> +                         "-lgcc_nonshared "
>>                           "-lgcc",
>>                           "-lgcc_eh"
>>  #ifdef USE_LIBUNWIND_EXCEPTIONS
>> @@ -1591,7 +1593,9 @@ init_spec (void)
>>           /* Ug.  We don't know shared library extensions.  Hope that
>>              systems that use this form don't do shared libraries.  */
>>           init_gcc_specs (&obstack,
>> +                         "libgcc_nonshared.a%s "
>>                           "-lgcc_s",
>> +                         "libgcc_nonshared.a%s "
>>                           "libgcc.a%s",
>>                           "libgcc_eh.a%s"
>
> Why do you need to link libgcc_nonshared.a twice here?  -lgcc_s surely won't
> add any new __cpu* undefined references.

The one added for -lgcc_s is for building shared C++ library since -lgcc isn't
used and only -lgcc_s is used.  The one added for -lgcc is for static linking
since -lgcc_s isn't used.  I updated the patch to add some testcases
for -static.
I couldn't find a way to add tests for:

export/build/gnu/gcc/build-x86_64-linux/gcc/xg++
-B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -O2    -c -o main.o
main.cc
/export/build/gnu/gcc/build-x86_64-linux/gcc/xg++
-B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -shared -fPIC -O2  -o
libmv20.so mv20.cc
-L/export/build/gnu/gcc/build-x86_64-linux/x86_64-unknown-linux-gnu/libstdc++-v3/src/.libs
/export/build/gnu/gcc/build-x86_64-linux/gcc/xg++
-B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -O2  -o x main.o
libmv20.so -Wl,-R,.
-L/export/build/gnu/gcc/build-x86_64-linux/x86_64-unknown-linux-gnu/libstdc++-v3/src/.libs
/usr/local/bin/ld: x: hidden symbol `__cpu_model' in
/export/build/gnu/gcc/build-x86_64-linux/gcc/libgcc_nonshared.a(cpuinfo.o)
is referenced by DSO
/usr/local/bin/ld: final link failed: Bad value
collect2: error: ld returned 1 exit status

>> @@ -424,3 +424,8 @@ __cpu_indicator_init (void)
>>
>>    return 0;
>>  }
>> +
>> +#if defined SHARED && !defined _WIN32
>> +__asm__ (".symver __cpu_indicator_init, __cpu_indicator_init@GCC_4.8.0");
>> +__asm__ (".symver __cpu_model, __cpu_model@GCC_4.8.0");
>> +#endif
>
> Will this work on Solaris?
> I'd say you at least want to also guard with some configure check if
> .symver is supported by assembler.
>

I updated my patch with:

@@ -424,3 +424,8 @@ __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");
+#endif

diff --git a/libgcc/config/i386/t-linux b/libgcc/config/i386/t-linux
index 4f47f7b..11bb46e 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
+HOST_LIBGCC2_CFLAGS += -mlong-double-80 -DUSE_ELF_SYMVER

OK for master?

-- 
H.J.