Cross compiling libvpx on Android for x86_64

[Dan Liang]

Hi,

I'm trying to run the vpxenc on my Android 7.0 device and I downloaded the latest code of libvpx.

What I did are:

$NDK/build/tools/make_standalone_toolchain.py --arch x86_64 --install-dir ~/my_standalone_toolchain

export PATH=$PATH:~/my_standalone_toolchain/bin

CROSS=x86_64-linux-android- CC=clang CXX=clang++ ASFLAGS="-D__ANDROID__" ~/libvpx/configure --target=x86_64-android-gcc --sdk-path=$NDK

The confgiure script runs successfully:

  enabling vp8_encoder

  enabling vp8_decoder

  enabling vp9_encoder

  enabling vp9_decoder

Configuring for target 'x86_64-android-gcc'

  enabling x86_64

  enabling runtime_cpu_detect

  enabling mmx

  enabling sse

  enabling sse2

  enabling sse3

  enabling ssse3

  enabling sse4_1

  enabling avx

  enabling avx2

  using yasm

  enabling postproc

  enabling webm_io

  enabling libyuv

Creating makefiles for x86_64-android-gcc libs

Creating makefiles for x86_64-android-gcc examples

Creating makefiles for x86_64-android-gcc tools

Creating makefiles for x86_64-android-gcc docs

And the compilation is OK. However, when the tool “vpxenc” is pushed to the Android device, there's an error:

"vpxenc": error: only position independent executables (PIE) are supported.

Aborted

So I modified the .mk files manually to add the flags:

CFLAGS += -fPIE

CXXFLAGS += -fPIE

LDFLAGS += -fPIE -pie

However, there're errors during the linking phase for vpxdec:

    [LD] vpxdec

/home/anonymous/my_standalone_toolchain/bin/../lib/gcc/x86_64-linux-android/4.9.x/../../../../x86_64-linux-android/bin/ld: error: ./libvpx.a(fwd_txfm_ssse3_x86_64.asm.o): requires dynamic R_X86_64_32 reloc which may overflow at runtime; recompile with -fPIC

/home/anonymous/my_standalone_toolchain/bin/../lib/gcc/x86_64-linux-android/4.9.x/../../../../x86_64-linux-android/bin/ld: error: ./libvpx.a(quantize_ssse3_x86_64.asm.o): requires dynamic R_X86_64_32 reloc which may overflow at runtime; recompile with -fPIC

/home/anonymous/my_standalone_toolchain/bin/../lib/gcc/x86_64-linux-android/4.9.x/../../../../x86_64-linux-android/bin/ld: error: ./libvpx.a(subpel_variance_sse2.asm.o): requires dynamic R_X86_64_32 reloc which may overflow at runtime; recompile with -fPIC

clang38++: error: linker command failed with exit code 1 (use -v to see invocation)

But even I added -fPIC, the same error is seen.

Could anyone help me on this issue?

Thanks a lot!

[Johann Koenig]

On Wed, Mar 15, 2017 at 1:51 AM, Dan Liang <redapp...@gmail.com> wrote:
> $NDK/build/tools/make_standalone_toolchain.py --arch x86_64

Unfortunately I don't have any x86_64 android devices to check this,
but a patch was upload a while ago to AOSP to try to address a build
issue:
https://android-review.googlesource.com/#/c/139090/

I'm not sure if this is the same issue you are seeing. The patch was
not accepted upstream because there was no explanation of how the fix
worked.

[Johann Koenig]

On Wed, Mar 15, 2017 at 1:51 AM, Dan Liang <redapp...@gmail.com> wrote:

> So I modified the .mk files manually to add the flags:
> CFLAGS += -fPIE
> CXXFLAGS += -fPIE
> LDFLAGS += -fPIE -pie

You can also pass '--enable-pic' to configure

[Dan Liang]

Thank you Johann. With the option '--enable-pic', the PIC issue found in the linking stage has gone. But the PIE issue is still there when the command line vpxenc is run. Since there's no option of '--enable-pie' in configure script, I manually added the '-fPIE' option as I mentioned previously. Now the vpxenc can work well on the x86_64 Android Device(Android 7.0).

It seems x86 and x86_64 target requires this -fPIE option as I tested.

You could try with the x86_64 Android Emulator.

在 2017年3月16日星期四 UTC+8上午12:22:46，Johann写道：

[Dan Liang]

That patch was submitted two years ago by me when I tried to built the vp8 codecs with x86_64 SIMD optimizations in the libvpx contained in AOSP. As mediaserver/media.codec is running in 32b env, there was no real requirement to enable the 64b sw codecs, it was just an experiment. Would you like me to continue this job?

在 2017年3月15日星期三 UTC+8下午11:46:37，Johann写道：

[Johann Koenig]

On Wed, Mar 15, 2017 at 8:40 PM, Dan Liang <redapp...@gmail.com> wrote:
> That patch was submitted two years ago by me when I tried to built the vp8
> codecs with x86_64 SIMD optimizations in the libvpx contained in AOSP. As
> mediaserver/media.codec is running in 32b env, there was no real requirement
> to enable the 64b sw codecs, it was just an experiment. Would you like me to
> continue this job?

Ah sorry! I totally missed that you were the author. If it's still
using 32bit internally, I don't think it's important to fix right now.