[patch bfd]: Fix PR ld/12742 for windows targets

[Kai Tietz]

Hi,

2012/3/10 xunxun <xunxun1982@gmail.com>:
> On Sat, Mar 10, 2012 at 3:54 AM, Kai Tietz <ktietz70@googlemail.com> wrote:
>> Hi,
>>
>> this patch adds compatible implementation of dlfcn API on Windows
>> targets, if this header/API isn't present.
>>
>> ChangeLog
>>
>> 2012-03-09  Kai Tietz  <ktietz@redhat.com>
>>
>>        PR ld/12742
>>        * configure.in (AC_CHECK_HEADERS): Test for windows.h and dlfcn.h.
>>        * plugin.c: Guard include of dlfcn.h if HAVE_DLFCN_H is defined.
>>        Add windows.h header include if HAVE_WINDOWS_H is defined.
>>        (dlerror): New static function if windows variant is used instead
>>        of dlfcn.h.
>>        (dlclose): Likewise.
>>        (dlopen): Likewise.
>>        (dlsym): Likewise.
>>        * configure: Regenerated.
>>        * config.in: Regenerated.
>>
>> Tested for i686-w64-mingw32 and x86_64-w64-mingw32.  Ok for apply?
>>
>> Regards,
>> Kai
>>
>> Index: config.in
>> ===================================================================
>> RCS file: /cvs/src/src/bfd/config.in,v
>> retrieving revision 1.49
>> diff -u -p -r1.49 config.in
>> --- config.in   12 May 2011 07:41:40 -0000      1.49
>> +++ config.in   9 Mar 2012 19:38:18 -0000
>> @@ -245,6 +245,9 @@
>>  /* Define if <sys/procfs.h> has win32_pstatus_t. */
>>  #undef HAVE_WIN32_PSTATUS_T
>>
>> +/* Define to 1 if you have the <windows.h> header file. */
>> +#undef HAVE_WINDOWS_H
>> +
>>  /* Define to 1 if you have the <zlib.h> header file. */
>>  #undef HAVE_ZLIB_H
>>
>> Index: configure
>> ===================================================================
>> RCS file: /cvs/src/src/bfd/configure,v
>> retrieving revision 1.359
>> diff -u -p -r1.359 configure
>> --- configure   25 Feb 2012 19:51:31 -0000      1.359
>> +++ configure   9 Mar 2012 19:38:21 -0000
>> @@ -13508,6 +13508,22 @@ fi
>>
>>  fi
>>
>> +
>> +for ac_header in windows.h dlfcn.h
>> +do :
>> +  as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
>> +ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header"
>> "$ac_includes_default"
>> +eval as_val=\$$as_ac_Header
>> +   if test "x$as_val" = x""yes; then :
>> +  cat >>confdefs.h <<_ACEOF
>> +#define `$as_echo "HAVE_$ac_header" | $as_tr_cpp` 1
>> +_ACEOF
>> +
>> +fi
>> +
>> +done
>> +
>> +
>>  { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether string.h
>> and strings.h may both be included" >&5
>>  $as_echo_n "checking whether string.h and strings.h may both be
>> included... " >&6; }
>>  if test "${gcc_cv_header_string+set}" = set; then :
>> Index: configure.in
>> ===================================================================
>> RCS file: /cvs/src/src/bfd/configure.in,v
>> retrieving revision 1.307
>> diff -u -p -r1.307 configure.in
>> --- configure.in        25 Feb 2012 19:51:32 -0000      1.307
>> +++ configure.in        9 Mar 2012 19:38:21 -0000
>> @@ -190,6 +190,9 @@ AC_CHECK_HEADERS(fcntl.h sys/file.h sys/
>>  GCC_HEADER_STDINT(bfd_stdint.h)
>>  AC_HEADER_TIME
>>  AC_HEADER_DIRENT
>> +
>> +AC_CHECK_HEADERS(windows.h dlfcn.h)
>> +
>>  ACX_HEADER_STRING
>>  AC_CHECK_FUNCS(fcntl getpagesize setitimer sysconf fdopen getuid getgid fileno)
>>  AC_CHECK_FUNCS(strtoull)
>> Index: plugin.c
>> ===================================================================
>> RCS file: /cvs/src/src/bfd/plugin.c,v
>> retrieving revision 1.14
>> diff -u -p -r1.14 plugin.c
>> --- plugin.c    11 Jul 2011 15:03:07 -0000      1.14
>> +++ plugin.c    9 Mar 2012 19:38:22 -0000
>> @@ -25,7 +25,13 @@
>>  #if BFD_SUPPORTS_PLUGINS
>>
>>  #include <assert.h>
>> +#ifdef HAVE_DLFCN_H
>>  #include <dlfcn.h>
>> +#elif defined (HAVE_WINDOWS_H)
>> +#include <windows.h>
>> +#else
>> +#error Unknown how to handle dynamic-load-libraries.
>> +#endif
>>  #include <stdarg.h>
>>  #include "plugin-api.h"
>>  #include "sysdep.h"
>> @@ -34,6 +40,37 @@
>>  #include "libiberty.h"
>>  #include <dirent.h>
>>
>> +#if !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)
>> +
>> +#define RTLD_NOW 0      /* Dummy value.  */
>> +
>> +static void *
>> +dlopen (const char *file, int mode ATTRIBUTE_UNUSED)
>> +{
>> +  return LoadLibrary (file);
>> +}
>> +
>> +static void *
>> +dlsym (void *handle, const char *name)
>> +{
>> +  return GetProcAddress (handle, name);
>> +}
>> +
>> +static int ATTRIBUTE_UNUSED
>> +dlclose (void *handle)
>> +{
>> +  FreeLibrary (handle);
>> +  return 0;
>> +}
>> +
>> +static const char *
>> +dlerror (void)
>> +{
>> +  return "Unable to load DLL.";
>> +}
>> +
>> +#endif /* !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)  */
>> +
>>  #define bfd_plugin_close_and_cleanup
>> _bfd_generic_close_and_cleanup
>>  #define bfd_plugin_bfd_free_cached_info
>> _bfd_generic_bfd_free_cached_info
>>  #define bfd_plugin_new_section_hook
>> _bfd_generic_new_section_hook
>
> why to add static?

Because we have to have those symbols only within that TU.  Making
them global would lead for users of dlfcn-win32 to issues.

> And I think dlclose is
> int ATTRIBUTE_UNUSED
> dlclose (void *handle)
> {
>  bool ret;
>  ret = FreeLibrary (handle);
>  ret = !ret;
>  return (int) ret;
> }
> The similar is better.
>
> --
> Best Regards,
> xunxun

I used the code from ld's plugin code here.  The dlcose isn't used in
this TU, so I marked it by attribute UNUSED, just to provide complete
API here.  We can even remove it here.

Regards,
Kai