Problem compiling for Android

[lemberh]

I have followed this tutorial from wiki.
I used sources from the latest release https://github.com/xianyi/OpenBLAS/releases/tag/v0.3.10

This is my build script after the path adjustment

# Set path to ndk-bundle
export NDK_BUNDLE_DIR=/Users/rnaz/Library/Android/sdk/ndk/21.3.6528147
# Export PATH to contain directories of clang and aarch64-linux-android-* utilities
export PATH=${NDK_BUNDLE_DIR}/toolchains/aarch64-linux-android-4.9/prebuilt/darwin-x86_64/bin/:${NDK_BUNDLE_DIR}/toolchains/llvm/prebuilt/darwin-x86_64/bin:$PATH
# Setup LDFLAGS so that loader can find libgcc and pass -lm for sqrt
export LDFLAGS="-L${NDK_BUNDLE_DIR}/toolchains/aarch64-linux-android-4.9/prebuilt/darwin-x86_64/lib/gcc/aarch64-linux-android/4.9.x -lm"
# Setup the clang cross compile options
export CLANG_FLAGS="-target aarch64-linux-android --sysroot ${NDK_BUNDLE_DIR}/platforms/android-23/arch-arm64 -gcc-toolchain ${NDK_BUNDLE_DIR}/toolchains/aarch64-linux-android-4.9/prebuilt/darwin-x86_64/"
# Compile
make TARGET=ARMV8 ONLY_CBLAS=1 AR=ar CC="clang ${CLANG_FLAGS}" HOSTCC=gcc -j4

Compilation ended with an error:

clang: warning: argument unused during compilation: '-install_name /Users/rnaz/StudioProjects/OpenBLAS/exports/../libopenblas.0.dylib' [-Wunused-command-line-argument]
clang: warning: argument unused during compilation: '-dynamiclib' [-Wunused-command-line-argument]
/Users/rnaz/Library/Android/sdk/ndk/21.0.6113669/toolchains/llvm/prebuilt/darwin-x86_64/bin/aarch64-linux-android-ld:osx.def: file format not recognized; treating as linker script
/Users/rnaz/Library/Android/sdk/ndk/21.0.6113669/toolchains/llvm/prebuilt/darwin-x86_64/bin/aarch64-linux-android-ld:osx.def:2: syntax error
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[1]: *** [libopenblas_haswellp-r0.3.10.dylib] Error 1
make: *** [shared] Error 2

Also if I just compile with make compilation succeed
Can anybody suggest what might be wrong

[martin-frbg]

Can you post the contents (or first few lines) of the osx.def the linker does not like ?

[lemberh]

This is actually executable file
here is the result of head -5 /Users/rnaz/Library/Android/sdk/ndk/21.3.6528147/toolchains/llvm/prebuilt/darwin-x86_64/bin/aarch64-linux-android-ld

�����@� H__PAGEZEROx__TEXT��__text__TEXT���__stubs__TEXT
��
�__stub_helper__TEXT��>���__cstring__TEXT���
��__const__TEXT�����__unwind_info__TEXT�(%�__eh_frame__TEXT����__DATA���__program_vars__DATA�(�__got__DATA(�X(�k__nl_symbol_ptr__DATA����v__la_symbol_ptr__DATA��X��x__const__DATA�(��__data__DATA@�PJ@�__common__DATA��__bss__DATA��k~H__LINKEDITp D��D�"�0�� ���h��0p u�z
PsXw �
/usr/lib/dyld�s�Y:���ۂb&$

I have 3 versions of ndk and on all of them is the same problem, also it is reproducible for ARMV7 build
Versions of NDK:
21.0.6113669
21.2.6472646
21.3.6528147

And also I'm using Mac-OS

[martin-frbg]

Hm, that file is supposed to be the list of symbols (functions) exported by the shared library. I need to check how it is supposed to look for osx, maybe what you are seeing is native osx or ios format and nobody tried to cross-compile for Android on OSX recently

[martin-frbg]

BTW, as you wrote that just compiling with make succeeded (that is, without passing the CLANG_CFLAGS to clang, I assume ?),
did it result in a usable library for Android ?

[brada4]

Add parameter FC=none because native fortran compiler makes native OSX fortran objects that android/linux clang will not link anywhere.

[lemberh]

Thanks for the help guys!
My first problem was because I didn't do make clean after compiling with just make it would be the version for OSX
But after that, I was still getting errors like this:

clang -target arm-linux-androideabi -marm -mfpu=vfp -mfloat-abi=softfp --sysroot /Users/rnaz/Library/Android/sdk/ndk/21.3.6528147/platforms/android-23/arch-arm -gcc-toolchain /Users/rnaz/Library/Android/sdk/ndk/21.3.6528147toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/arm-linux-androideabi/bin -O2 -DMAX_STACK_ALLOC=2048 -marm -mfloat-abi=softfp -Wall -DF_INTERFACE_GFORT -fPIC -DNO_LAPACK -DNO_LAPACKE -DSMP_SERVER -DNO_WARMUP -DMAX_CPU_NUMBER=8 -DMAX_PARALLEL_NUMBER=1 -DVERSION="0.3.10" -mfpu=neon -march=armv7-a -UASMNAME -UASMFNAME -UNAME -UCNAME -UCHAR_NAME -UCHAR_CNAME -DASMNAME=cblas_dsdot -DASMFNAME=cblas_dsdot_ -DNAME=cblas_dsdot_ -DCNAME=cblas_dsdot -DCHAR_NAME="cblas_dsdot_" -DCHAR_CNAME="cblas_dsdot" -DNO_AFFINITY -I.. -I. -UDOUBLE -UCOMPLEX -DCBLAS -c dsdot.c -o cblas_dsdot.o
imax.c:39:10: fatal error: 'stdio.h' file not found
#include <stdio.h>
^~~~~~~~~

Finally, I have managed to compile the project with help from this comment #2005 (comment)
I think documentation from the Wiki doesn't work because of those changes in NDK19 https://developer.android.com/ndk/guides/other_build_systems#overview

This is my working script

export NDK=/Users/rnaz/Library/Android/sdk/ndk/21.3.6528147
export TOOLCHAIN=$NDK/toolchains/llvm/prebuilt/darwin-x86_64
make \
    TARGET=ARMV7 \
    ONLY_CBLAS=1 \
    CC="$TOOLCHAIN"/bin/armv7a-linux-androideabi21-clang \
    AR="$TOOLCHAIN"/bin/arm-linux-androideabi-ar \
    HOSTCC=gcc \
    ARM_SOFTFP_ABI=1 \
    -j4

[brada4]

Add a paragraph with your NDK version and the command line to wiki, it is open to all github

[martin-frbg]

Thank you very much for updating the wiki - in particular the added script for X86 should solve #2768

[lemberh]

No problem. And thank you guys for maintaining this library it helped me a lot in my project