libsdl2_image error with gcc: error: attributes should be specified before the declarator in a function definition

[barracuda156]

The error confirmed on Tiger and Snow Leopard when building with gcc:

libtool: compile:  /opt/local/bin/gcc-mp-7 -DPACKAGE_NAME=\"SDL2_image\" -DPACKAGE_TARNAME=\"SDL2_image\" -DPACKAGE_VERSION=\"2.8.2\" "-DPACKAGE_STRING=\"SDL2_image 2.8.2\"" -DPACKAGE_BUGREPORT=\"https://github.com/libsdl-org/SDL_image/issues\" -DPACKAGE_URL=\"\" -DHAVE_STDIO_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_STRINGS_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_UNISTD_H=1 -DSTDC_HEADERS=1 -DHAVE_DLFCN_H=1 -DLT_OBJDIR=\".libs/\" -DSDL_BUILD_MAJOR_VERSION=2 -DSDL_BUILD_MINOR_VERSION=8 -DSDL_BUILD_MICRO_VERSION=2 -DPACKAGE=\"SDL2_image\" -DVERSION=\"2.8.2\" -DUSE_STBIMAGE=1 -DLOAD_JPG=1 -DLOAD_PNG=1 -DLOAD_TIF=1 -DLOAD_WEBP=1 -DLOAD_BMP=1 -DLOAD_GIF=1 -DLOAD_LBM=1 -DLOAD_PCX=1 -DLOAD_PNM=1 -DLOAD_SVG=1 -DLOAD_TGA=1 -DLOAD_XCF=1 -DLOAD_XPM=1 -DLOAD_XV=1 -DLOAD_QOI=1 -DSDL_IMAGE_SAVE_PNG=1 -DSDL_IMAGE_SAVE_JPG=1 -I. -I./include -I/opt/local/include -I/opt/local/include/webp -pipe -Os -arch ppc -DSDL_IMAGE_USE_COMMON_BACKEND -D_THREAD_SAFE -I/opt/local/include/SDL2 -Wall -fvisibility=hidden -MT src/libSDL2_image_la-IMG_webp.lo -MD -MP -MF src/.deps/libSDL2_image_la-IMG_webp.Tpo -c src/IMG_webp.c  -fno-common -DPIC -o src/.libs/libSDL2_image_la-IMG_webp.o
libtool: compile:  /opt/local/bin/gcc-mp-7 -DPACKAGE_NAME=\"SDL2_image\" -DPACKAGE_TARNAME=\"SDL2_image\" -DPACKAGE_VERSION=\"2.8.2\" "-DPACKAGE_STRING=\"SDL2_image 2.8.2\"" -DPACKAGE_BUGREPORT=\"https://github.com/libsdl-org/SDL_image/issues\" -DPACKAGE_URL=\"\" -DHAVE_STDIO_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_STRINGS_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_UNISTD_H=1 -DSTDC_HEADERS=1 -DHAVE_DLFCN_H=1 -DLT_OBJDIR=\".libs/\" -DSDL_BUILD_MAJOR_VERSION=2 -DSDL_BUILD_MINOR_VERSION=8 -DSDL_BUILD_MICRO_VERSION=2 -DPACKAGE=\"SDL2_image\" -DVERSION=\"2.8.2\" -DUSE_STBIMAGE=1 -DLOAD_JPG=1 -DLOAD_PNG=1 -DLOAD_TIF=1 -DLOAD_WEBP=1 -DLOAD_BMP=1 -DLOAD_GIF=1 -DLOAD_LBM=1 -DLOAD_PCX=1 -DLOAD_PNM=1 -DLOAD_SVG=1 -DLOAD_TGA=1 -DLOAD_XCF=1 -DLOAD_XPM=1 -DLOAD_XV=1 -DLOAD_QOI=1 -DSDL_IMAGE_SAVE_PNG=1 -DSDL_IMAGE_SAVE_JPG=1 -I. -I./include -I/opt/local/include -I/opt/local/include/webp -pipe -Os -arch ppc -DSDL_IMAGE_USE_COMMON_BACKEND -D_THREAD_SAFE -I/opt/local/include/SDL2 -Wall -fvisibility=hidden -MT src/libSDL2_image_la-IMG_stb.lo -MD -MP -MF src/.deps/libSDL2_image_la-IMG_stb.Tpo -c src/IMG_stb.c -o src/libSDL2_image_la-IMG_stb.o >/dev/null 2>&1
libtool: compile:  /opt/local/bin/gcc-mp-7 -DPACKAGE_NAME=\"SDL2_image\" -DPACKAGE_TARNAME=\"SDL2_image\" -DPACKAGE_VERSION=\"2.8.2\" "-DPACKAGE_STRING=\"SDL2_image 2.8.2\"" -DPACKAGE_BUGREPORT=\"https://github.com/libsdl-org/SDL_image/issues\" -DPACKAGE_URL=\"\" -DHAVE_STDIO_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_STRINGS_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_UNISTD_H=1 -DSTDC_HEADERS=1 -DHAVE_DLFCN_H=1 -DLT_OBJDIR=\".libs/\" -DSDL_BUILD_MAJOR_VERSION=2 -DSDL_BUILD_MINOR_VERSION=8 -DSDL_BUILD_MICRO_VERSION=2 -DPACKAGE=\"SDL2_image\" -DVERSION=\"2.8.2\" -DUSE_STBIMAGE=1 -DLOAD_JPG=1 -DLOAD_PNG=1 -DLOAD_TIF=1 -DLOAD_WEBP=1 -DLOAD_BMP=1 -DLOAD_GIF=1 -DLOAD_LBM=1 -DLOAD_PCX=1 -DLOAD_PNM=1 -DLOAD_SVG=1 -DLOAD_TGA=1 -DLOAD_XCF=1 -DLOAD_XPM=1 -DLOAD_XV=1 -DLOAD_QOI=1 -DSDL_IMAGE_SAVE_PNG=1 -DSDL_IMAGE_SAVE_JPG=1 -I. -I./include -I/opt/local/include -I/opt/local/include/webp -pipe -Os -arch ppc -DSDL_IMAGE_USE_COMMON_BACKEND -D_THREAD_SAFE -I/opt/local/include/SDL2 -Wall -fvisibility=hidden -MT src/libSDL2_image_la-IMG_xv.lo -MD -MP -MF src/.deps/libSDL2_image_la-IMG_xv.Tpo -c src/IMG_xv.c -o src/libSDL2_image_la-IMG_xv.o >/dev/null 2>&1
src/IMG_webp.c:74:1: error: attributes should be specified before the declarator in a function definition
 int IMG_InitWEBP()
 ^~~
make[1]: *** [src/libSDL2_image_la-IMG_webp.lo] Error 1
make[1]: *** Waiting for unfinished jobs....
mv -f src/.deps/libSDL2_image_la-IMG_xv.Tpo src/.deps/libSDL2_image_la-IMG_xv.Plo
make[1]: *** Waiting for unfinished jobs....
mv -f src/.deps/libSDL2_image_la-IMG_svg.Tpo src/.deps/libSDL2_image_la-IMG_svg.Plo
mv -f src/.deps/libSDL2_image_la-IMG_stb.Tpo src/.deps/libSDL2_image_la-IMG_stb.Plo
make[1]: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_devel_libsdl2_image/libsdl2_image/work/SDL2_image-2.8.2'
make: *** [all-recursive] Error 1

This happens due to a wrong code in IMG_webp.c:

#ifdef __APPLE__
    /* Need to turn off optimizations so weak framework load check works */
    __attribute__ ((optnone))
#endif

Once this is removed, the port builds fine. So perhaps it is clang-only and should be conditional, or otherwise some alternative fix is needed.

[barracuda156]

UPD. Hmm, apparently the same block is used in two other places, but only here it fails.

Commit introducing it: ​https://github.com/libsdl-org/SDL_image/commit/25a57e23071b0d5a70c1a417966fb37bb6e78033

[kencu (Ken)]

moving the attribute setting before the function declaration like this also works, and I think this is the proper way to do it anyway:

#ifdef __APPLE__
    /* Need to turn off optimizations so weak framework load check works */
    __attribute__ ((optnone))
#endif
int IMG_InitWEBP()

[kencu (Ken)]

same issue in libsdl2_mixer (although the build there later fails with other errors on 10.5 once this is fixed).

[barracuda156]

Replying to kencu:

moving the attribute setting before the function declaration like this also works, and I think this is the proper way to do it anyway:

#ifdef __APPLE__
    /* Need to turn off optimizations so weak framework load check works */
    __attribute__ ((optnone))
#endif
int IMG_InitWEBP()

Thank you, Ken!

I will try that, and we should make a PR to allow building with GCC.

[barracuda156]

Replying to kencu:

moving the attribute setting before the function declaration like this also works, and I think this is the proper way to do it anyway:

#ifdef __APPLE__
    /* Need to turn off optimizations so weak framework load check works */
    __attribute__ ((optnone))
#endif
int IMG_InitWEBP()

Yes, it works. GCC says it ignores it :)

src/IMG_webp.c:79:1: warning: 'optnone' attribute directive ignored [-Wattributes]
   79 | {
      | ^

[kencu (Ken)]

it looks like optnone is not an attribute accepted by gcc.

there is a different specifier used

__attribute__((optimize("O0"))

the exact location where this can be placed in the function definition is also a bit of reading, eg

​https://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html

[barracuda156]

Replying to kencu:

it looks like optnone is not an attribute accepted by gcc.

there is a different specifier used

__attribute__((optimize("O0"))

the exact location where this can be placed in the function definition is also a bit of reading, eg

​https://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html

Could you suggest how to better do it in this case?

Everything builds with just moving those as you suggested earlier, but of course it is better to use a supported attribute.

16. S. I will convert the PR into a draft for now, so it is not accidentally merged: ​https://github.com/macports/macports-ports/pull/23293

[barracuda156]

Wonder if SDL upstream may be interested to have it fixed, it is a genuine bug in their code then.