[Bug c/31680] New: Cannot create DLL with exported stdcall functions because compiler exports the functions without the @N decoration

[Bug c/31680] New: Cannot create DLL with exported stdcall functions because compiler exports the functions without the @N decoration

[tobivollebregt at gmail dot com]

Take the following C test code. I want to make a DLL which exports stdcall
HelloWorld function.

test.c:

__attribute__((dllexport)) void __attribute__((__stdcall__)) HelloWorld()
{
}

Compiling & linking it gives the following error during linking with GCC 4.3.0,
while it works fine with GCC 3.4.5.

$ i586-mingw32msvc-gcc -c -o test.o test.c
$ i586-mingw32msvc-gcc -shared -o test.dll test.o
Cannot export HelloWorld: symbol not found
collect2: ld returned 1 exit status

Examining the object file seems to reveal the problem, especially when compared
to the GCC 3.4.5 mingw crosscompiler which is in Debian.

GCC 4.3.0:

$ i586-mingw32msvc-nm test.o | grep HelloWorld
00000000 T _HelloWorld@0

$ strings test.o | grep HelloWorld
 -export:HelloWorld
_HelloWorld@0

GCC 3.4.5:

$ i586-mingw32msvc-nm test.o | grep HelloWorld
00000000 T _HelloWorld@0

$ strings test.o | grep HelloWorld
 -export:HelloWorld@0
_HelloWorld@0

Notice the subtle difference in output of the last command. Between 3.4.5 and
4.3.0 the @0 stdcall decoration in the -export:HelloWorld@0 line got lost,
which makes it impossible to link DLLs with exported stdcall functions.

Here are some details about the compiler versions used for testing:

$ i586-mingw32msvc-gcc-4.3.0 -v
Using built-in specs.
Target: i586-mingw32msvc
Configured with: ../gcc/configure --prefix=/opt/mingw --target=i586-mingw32msvc
--enable-languages=c --disable-multilib --disable-shared --enable-threads=win32
--enable-version-specific-runtime-libs --enable-sjlj-exceptions :
(reconfigured) ../gcc/configure --prefix=/opt/mingw --target=i586-mingw32msvc
--enable-languages=c,c++ --disable-multilib --disable-shared
--enable-threads=win32 --enable-version-specific-runtime-libs
--enable-sjlj-exceptions
Thread model: win32
gcc version 4.3.0 20070424 (experimental)

$ i586-mingw32msvc-gcc-3.4.5 -v
Reading specs from /usr/lib/gcc/i586-mingw32msvc/3.4.5/specs
Configured with:
/build/buildd/mingw32-3.4.5.20060117.1.dfsg/build_dir/src/gcc-3.4.5-20060117-1-dfsg/configure
-v --prefix=/usr --target=i586-mingw32msvc --enable-languages=c,c++
--enable-threads --enable-sjlj-exceptions --disable-multilib
--enable-version-specific-runtime-libs
Thread model: win32
gcc version 3.4.5 (mingw special)


-- 
           Summary: Cannot create DLL with exported stdcall functions
                    because compiler exports the functions without the @N
                    decoration
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: tobivollebregt at gmail dot com
 GCC build triplet: i486-linux-gnu
  GCC host triplet: i486-linux-gnu
GCC target triplet: i586-mingw32msvc


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31680

[Bug c/31680] Cannot create DLL with exported stdcall functions because compiler exports the functions without the @N decoration

[tobivollebregt at gmail dot com]

------- Comment #1 from tobivollebregt at gmail dot com  2007-04-24 11:01 -------
Created an attachment (id=13434)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=13434&action=view)
Shell script which I used to create the 4.3.0 cross compiler

The used binutils are the "official" binutils. The mingw-runtime and w32-api
came from http://sourceforge.net/project/showfiles.php?group_id=2435.

Just FYI, the md5sums of the respective files I used, are:

e26e2e06b6e4bf3acf1dc8688a94c0d1  binutils-2.17.tar.bz2
a9fdbd5162aa1ae0171c47f929adf938  mingw-runtime-3.12-src.tar.gz
be0b0219645a4ee0f3495c2abf90b5ad  w32api-3.9-src.tar.gz


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31680

[Bug c/31680] Cannot create DLL with exported stdcall functions because compiler exports the functions without the @N decoration

[tobivollebregt at gmail dot com]

------- Comment #2 from tobivollebregt at gmail dot com  2007-04-24 11:06 -------
Created an attachment (id=13435)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=13435&action=view)
Log of the compiler build.

Maybe the most useful line in the log:
Checked out revision 124096.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31680

[Bug target/31680] Cannot create DLL with exported stdcall functions because compiler exports the functions without the @N decoration

[dannysmith at users dot sourceforge dot net]

------- Comment #3 from dannysmith at users dot sourceforge dot net  2007-04-25 09:57 -------
Testing a patch.
Danny


-- 

dannysmith at users dot sourceforge dot net changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |dannysmith at users dot
                   |dot org                     |sourceforge dot net
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2007-04-25 09:57:55
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31680

[Bug target/31680] Cannot create DLL with exported stdcall functions because compiler exports the functions without the @N decoration

[dannysmith at users dot sourceforge dot net]

------- Comment #4 from dannysmith at users dot sourceforge dot net  2007-04-25 11:17 -------
Fixed.

Author: dannysmith
Date: Wed Apr 25 11:06:28 2007
New Revision: 124149

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=124149
Log:
        * config/i386/winnt.c (i386_pe_file_end): Strip only
        USER_LABEL_PREFIX when writing export name.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/i386/winnt.c


-- 

dannysmith at users dot sourceforge dot net changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.3.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31680