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Bug 4173

Summary: Error when compiling SDL_image for arm64-v8a with android
Product: SDL_image Reporter: tupan <rangelms>
Component: miscAssignee: Sam Lantinga <slouken>
Status: RESOLVED FIXED QA Contact: Sam Lantinga <slouken>
Severity: normal    
Priority: P2 CC: icculus, sylvain.becker
Version: 2.0.3   
Hardware: ARM   
OS: Android (All)   

Description tupan 2018-05-24 01:46:06 UTC 
Hi, I'm trying to compile SDL and all its extensions for some arm architecture. It worked well for arm7 but for arm64 it is throwing the following error:

/tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/libpng.a(pngrutil.o): In function `png_init_filter_functions':
tmp/tmp.cTucoeURHX/jni/SDL_image/external/libpng-1.6.32/pngrutil.c:4113: undefined reference to `png_init_filter_functions_neon'


The command I think is responsible is this one:

/workspace/android/android-ndk-r17/toolchains/llvm/prebuilt/linux-x86_64/bin/clang++ -Wl,-soname,libSDL2_image.so -shared --sysroot=/workspace/android/android-ndk-r17/platforms/android-21/arch-arm64 /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/objs/SDL2_image/IMG.o /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/objs/SDL2_image/IMG_bmp.o /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/objs/SDL2_image/IMG_gif.o /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/objs/SDL2_image/IMG_jpg.o /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/objs/SDL2_image/IMG_lbm.o /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/objs/SDL2_image/IMG_pcx.o /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/objs/SDL2_image/IMG_png.o /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/objs/SDL2_image/IMG_pnm.o /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/objs/SDL2_image/IMG_svg.o /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/objs/SDL2_image/IMG_tga.o /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/objs/SDL2_image/IMG_tif.o /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/objs/SDL2_image/IMG_webp.o /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/objs/SDL2_image/IMG_WIC.o /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/objs/SDL2_image/IMG_xcf.o /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/objs/SDL2_image/IMG_xpm.o /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/objs/SDL2_image/IMG_xv.o /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/objs/SDL2_image/IMG_xxx.o -Wl,--whole-archive /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/libwebpdecoder_static.a -Wl,--no-whole-archive /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/libpng.a /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/libwebp.a /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/libcpufeatures.a -lgcc -Wl,--exclude-libs,libgcc.a -latomic -Wl,--exclude-libs,libatomic.a /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/libSDL2.so  -gcc-toolchain /workspace/android/android-ndk-r17/toolchains/aarch64-linux-android-4.9/prebuilt/linux-x86_64 -target aarch64-none-linux-android -no-canonical-prefixes   -Wl,--build-id -Wl,--no-undefined -Wl,-z,noexecstack -Wl,-z,relro -Wl,-z,now -Wl,--warn-shared-textrel -Wl,--fatal-warnings  -L/workspace/android/android-ndk-r17/platforms/android-21/arch-arm64/usr/lib -lz -ldl -lc -lm -o /tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/libSDL2_image.so
make: *** [/tmp/tmp.cTucoeURHX/obj/local/arm64-v8a/libSDL2_image.so] Error 1



I checked the file and it has this where the error is found:

  4104 #ifdef PNG_FILTER_OPTIMIZATIONS
  4105    /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to
  4106     * call to install hardware optimizations for the above functions; simply
  4107     * replace whatever elements of the pp->read_filter[] array with a hardware
  4108     * specific (or, for that matter, generic) optimization.
  4109     *
  4110     * To see an example of this examine what configure.ac does when
  4111     * --enable-arm-neon is specified on the command line.
  4112     */
  4113    PNG_FILTER_OPTIMIZATIONS(pp, bpp);
  4114 #endif


Anyone here has any idea what I'm doing wrong or how to fix this issue?

Thanks in advance!
Comment 1 Ryan C. Gordon 2018-05-24 02:39:04 UTC 
My guess is that when libpng.a was built, it was built without libpng-1.6.32/arm/arm_init.c, but I can't untangle the build script to see why, or if I'm right.

(Alternately: it built it, but PNG_ARM_NEON_OPT was 0 or undefined?)

--ryan.
Comment 2 Sylvain 2018-05-24 10:18:27 UTC 
Hi,

If you want to disable neon for libpng you can patch the file external/libpng-1.6.32/Android.mk

by adding: 

LOCAL_CFLAGS += -DPNG_ARM_NEON_OPT=0


I run a few benchmarks and saw no improvement by using neon with arm64-v8a.


But, if you really want to compile with NEON, you can add that to the previous file : 


ifneq (,$(filter $(TARGET_ARCH),arm arm64))
    $(warning ** Try to compile with NEON for TARGET_ARCH= $(TARGET_ARCH))
      LOCAL_CFLAGS += -DPNG_ARM_NEON_CHECK_SUPPORTED -DPNG_ARM_NEON_FILE=\"contrib/arm-neon/android-ndk.c\"
      common_SRC_FILES += arm/arm_init.c arm/filter_neon_intrinsics.c arm/filter_neon.S 
      LOCAL_STATIC_LIBRARIES := cpufeatures
endif

LOCAL_STATIC_LIBRARIES := cpufeatures

$(call import-module,android/cpufeatures)
Comment 3 tupan 2018-05-24 12:39:01 UTC 
(In reply to Ryan C. Gordon from comment #1)
> My guess is that when libpng.a was built, it was built without
> libpng-1.6.32/arm/arm_init.c, but I can't untangle the build script to see
> why, or if I'm right.
> 
> (Alternately: it built it, but PNG_ARM_NEON_OPT was 0 or undefined?)
> 
> --ryan.

How can I check this?
Comment 4 tupan 2018-05-24 12:39:55 UTC 
(In reply to Sylvain from comment #2)
> Hi,
> 
> If you want to disable neon for libpng you can patch the file
> external/libpng-1.6.32/Android.mk
> 
> by adding: 
> 
> LOCAL_CFLAGS += -DPNG_ARM_NEON_OPT=0
> 
> 
> I run a few benchmarks and saw no improvement by using neon with arm64-v8a.
> 
> 
> But, if you really want to compile with NEON, you can add that to the
> previous file : 
> 
> 
> ifneq (,$(filter $(TARGET_ARCH),arm arm64))
>     $(warning ** Try to compile with NEON for TARGET_ARCH= $(TARGET_ARCH))
>       LOCAL_CFLAGS += -DPNG_ARM_NEON_CHECK_SUPPORTED
> -DPNG_ARM_NEON_FILE=\"contrib/arm-neon/android-ndk.c\"
>       common_SRC_FILES += arm/arm_init.c arm/filter_neon_intrinsics.c
> arm/filter_neon.S 
>       LOCAL_STATIC_LIBRARIES := cpufeatures
> endif
> 
> LOCAL_STATIC_LIBRARIES := cpufeatures
> 
> $(call import-module,android/cpufeatures)

It worked by adding the LOCAL_CFLAGS to the Android.mk! Thanks!

I wonder how this happened, though...
Comment 5 Sylvain 2018-10-17 06:45:25 UTC 
Was fixed by https://hg.libsdl.org/SDL_image/rev/ed8961044eba