[Bug c/57120] New: Plain C link with libgcc_s_sjlj-1.dll which not needed

["dongsheng.song at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57120

             Bug #: 57120
           Summary: Plain C link with libgcc_s_sjlj-1.dll which not needed
    Classification: Unclassified
           Product: gcc
           Version: 4.8.1
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: dongsheng.song@gmail.com


Here is example:

$ cat t-w32.c
long long do_div(long long a, long long b)
{
  return a/b;
}

i686-w64-mingw32-gcc -shared -o t-w32.dll t-w32.c
i686-w64-mingw32-objdump -x t-w32.dll  | grep "DLL Name"

gcc 4.8:
        DLL Name: libgcc_s_sjlj-1.dll
        DLL Name: KERNEL32.dll
        DLL Name: msvcrt.dll

gcc 4.7:
        DLL Name: KERNEL32.dll
        DLL Name: msvcrt.dll

Then I investigate why the gcc 4.8 output dll use libgcc_s_sjlj-1.dll,
I found t-w32.dll use the following symbols in libgcc_s_sjlj-1.dll:

i686-w64-mingw32-objdump -x t-w32.dll  | less

        DLL Name: libgcc_s_sjlj-1.dll
        vma:  Hint/Ord Member-Name Bound-To
        c200       41  __divdi3
        c20c      119  __udivdi3
        c218      121  __umoddi3

I think this is a regress, isn't it ?


I found in gcc/config/i386/mingw32.h:

/* Include in the mingw32 libraries with libgcc */
#ifdef ENABLE_SHARED_LIBGCC
#define SHARED_LIBGCC_SPEC " \
 %{static|static-libgcc:-lgcc -lgcc_eh} \
 %{!static: \
   %{!static-libgcc: \
     %{!shared: \
       %{!shared-libgcc:-lgcc -lgcc_eh} \
       %{shared-libgcc:-lgcc_s -lgcc} \
      } \
     %{shared:-lgcc_s -lgcc} \
    } \
  } "
#else
#define SHARED_LIBGCC_SPEC " -lgcc "
#endif

If I change '-lgcc_s -lgcc' to '-lgcc -lgcc_s', then gcc 4.8 will not use such
symbols like __divdi3 in libgcc_s_sjlj-1.dll, it back to gcc 4.7 behavior.

Because both lib/libgcc_s.a (libgcc_s_sjlj-1.dll）and
lib/gcc/i686-w64-mingw32/4.8.1/libgcc.a
export these symbols:

___divdi3
___moddi3
___moddi3
...

I think this change is hastily, should be rollback, or make
libgcc_s${LIBGCC_EH_EXTN}-1.dll
DO NOT export extra symbols which not owned their self.
>From gcc-bugs-return-421237-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Tue Apr 30 05:34:46 2013
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Subject: [Bug target/57098] ICE: in extract_insn, at recog.c:2154 (unrecognizable insn) with -mcmodel=large -msse4 and __builtin_shuffle()
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http://gcc.gnu.org/bugzilla/show_bug.cgi?idW098

Uros Bizjak <ubizjak at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                URL|                            |http://gcc.gnu.org/ml/gcc-p
                   |                            |atches/2013-04/msg01749.htm
                   |                            |l

--- Comment #3 from Uros Bizjak <ubizjak at gmail dot com> 2013-04-30 05:34:39 UTC ---
Author: uros
Date: Mon Apr 29 18:20:58 2013
New Revision: 198430

URL: http://gcc.gnu.org/viewcvs?rev\x198430&root=gcc&view=rev
Log:
    PR target/57098
    * config/i386/i386.c (ix86_expand_vec_perm): Validize constant memory.

testsuite/ChangeLog:

    PR target/57098
    * gcc.target/i386/pr57098.c: New test.


Added:
    trunk/gcc/testsuite/gcc.target/i386/pr57098.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/i386/i386.c
    trunk/gcc/testsuite/ChangeLog

Author: uros
Date: Mon Apr 29 22:16:04 2013
New Revision: 198434

URL: http://gcc.gnu.org/viewcvs?rev\x198434&root=gcc&view=rev
Log:
    Backport from mainline
    2013-04-29  Uros Bizjak  <ubizjak@gmail.com>

    PR target/44578
    * config/i386/i386.md (*zero_extendsidi2_rex64): Add "!" to m->?*y
    alternative.
    (*zero_extendsidi2): Ditto.

    Backport from mainline
    2013-04-29  Uros Bizjak  <ubizjak@gmail.com>

    PR target/57098
    * config/i386/i386.c (ix86_expand_vec_perm): Validize constant memory.

testsuite/ChangeLog:

    Backport from mainline
    2013-04-29  Uros Bizjak  <ubizjak@gmail.com>

    PR target/44578
    * gcc.target/i386/pr44578.c: New test.

    Backport from mainline
    2013-04-29  Uros Bizjak  <ubizjak@gmail.com>

    PR target/57098
    * gcc.target/i386/pr57098.c: New test.

Added:
    branches/gcc-4_8-branch/gcc/testsuite/gcc.target/i386/pr44578.c
    branches/gcc-4_8-branch/gcc/testsuite/gcc.target/i386/pr57098.c
Modified:
    branches/gcc-4_8-branch/gcc/ChangeLog
    branches/gcc-4_8-branch/gcc/config/i386/i386.c
    branches/gcc-4_8-branch/gcc/config/i386/i386.md
    branches/gcc-4_8-branch/gcc/config/i386/sse.md
    branches/gcc-4_8-branch/gcc/testsuite/ChangeLog

Author: uros
Date: Tue Apr 30 05:30:20 2013
New Revision: 198439

URL: http://gcc.gnu.org/viewcvs?rev\x198439&root=gcc&view=rev
Log:
    Backport from mainline
    2013-04-29  Uros Bizjak  <ubizjak@gmail.com>

    PR target/44578
    * config/i386/i386.md (*zero_extendsidi2_rex64): Add "!" to m->?*y
    alternative.
    (*zero_extendsidi2): Ditto.

    Backport from mainline
    2013-04-29  Uros Bizjak  <ubizjak@gmail.com>

    PR target/57098
    * config/i386/i386.c (ix86_expand_vec_perm): Validize constant memory.

testsuite/ChangeLog:

    Backport from mainline
    2013-04-29  Uros Bizjak  <ubizjak@gmail.com>

    PR target/44578
    * gcc.target/i386/pr44578.c: New test.

    Backport from mainline
    2013-04-29  Uros Bizjak  <ubizjak@gmail.com>

    PR target/57098
    * gcc.target/i386/pr57098.c: New test.


Added:
    branches/gcc-4_7-branch/gcc/testsuite/gcc.target/i386/pr44578.c
    branches/gcc-4_7-branch/gcc/testsuite/gcc.target/i386/pr57098.c
Modified:
    branches/gcc-4_7-branch/gcc/ChangeLog
    branches/gcc-4_7-branch/gcc/config/i386/i386.c
    branches/gcc-4_7-branch/gcc/config/i386/i386.md
    branches/gcc-4_7-branch/gcc/testsuite/ChangeLog