[llvm-dev] Help Building LLVM for Android

[Justin Giannone via llvm-dev]

Hey Guys,

I'm working on a project in Android related to System-level Audio DSP Effects for Tuning Android Audio.  I want to leverage Faust (https://faust.grame.fr/) to allow users to program their own filters.  Faust provides a libfaust implementation which includes a JIT Compiler which leverages LLVM and seems to be the best path for me to use.  Unfortunately I'm having problems cross-compiling LLVM for Android on my Windows Dev machine.  Wondering if anyone has any advice for me?

I've been trying to use the android-ndk cmake & toolchains to build LLVM so that I can cross-compile Faust against the Android LLVM build.  I've managed to get Android's cmake to generate an Android Gradle Ninja project, but when I try to build it I get lots of errors that seem to indicate that the Ninja project is invalid, such as the following errors : 

FAILED: cmTC_4a28c.exe

  cmd.exe /C "cd .  &&
  C:\Users\jgiannone\AppData\Local\Android\Sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\clang.exe
  CMakeFiles/cmTC_4a28c.dir/testCCompiler.c.obj -o cmTC_4a28c.exe
  -Wl,--out-implib,libcmTC_4a28c.dll.a
  -Wl,--major-image-version,0,--minor-image-version,0 -lkernel32 -luser32
  -lgdi32 -lwinspool -lshell32 -lole32 -loleaut32 -luuid -lcomdlg32
  -ladvapi32 && cd ."

  clang: error: unable to execute command: program not executable

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

  ninja: build stopped: subcommand failed.

Thanks!

 

[Justin Giannone via llvm-dev]

Hey Guys,

Still struggling with this.  Wondering if anyone has any recommendations?

The command I'm using to generate the Ninja Build Files and execute the build are :

AndroidSdkDir="$LOCALAPPDATA/Android/Sdk"
AndroidCmakeExe="$AndroidSdkDir/cmake/3.10.2.4988404/bin/cmake.exe"
AndroidNinjaExe="$AndroidSdkDir/cmake/3.10.2.4988404/bin/ninja.exe"
NdkBundle="$AndroidSdkDir/ndk-bundle/"
ToolchainFile="$NdkBundle/build/cmake/android.toolchain.cmake"
ArchTargets="armeabi-v7a"

$AndroidCmakeExe \
-DBUILD_SHARED_LIBS=1 \
-DLLVM_BUILD_LLVM_DYLIB=1 \
-DLLVM_BUILD_TOOLS=0 \
-DLLVM_BUILD_UTILS=0 \
-DLLVM_INCLUDE_BENCHMARKS=0 \
-DLLVM_INCLUDE_DOCS=0 \
-DLLVM_INCLUDE_EXAMPLES=0 \
-DLLVM_INCLUDE_GO_TESTS=0 \
-DLLVM_INCLUDE_RUNTIMES=1 \
-DLLVM_INCLUDE_TESTS=0 \
-DLLVM_INCLUDE_TOOLS=0 \
-DLLVM_INCLUDE_UTILS=0 \
\
-DLLVM_DEFAULT_TARGET_TRIPLE=armv7a-linux-androideabi \
-DLLVM_TARGET_ARCH=ARM \
-DLLVM_TARGETS_TO_BUILD=ARM \
\
-DPYTHON_EXECUTABLE="$NdkBundle/prebuilt/windows-x86_64/bin/python2.7.exe" \
-DANDROID_NDK="$NdkBundle" \
-DANDROID_ABI="$archTarget" \
\
-DCMAKE_INSTALL_PREFIX=../../build-android/armeabi-v7a \
-DCMAKE_CROSSCOMPILING=True \
-DCMAKE_SYSTEM_NAME=Android \
-DANDROID_PLATFORM=android-21 \
-DCMAKE_SYSTEM_VERSION=21 \
-DCMAKE_ANDROID_NDK="$NdkBundle" \
-DCMAKE_TOOLCHAIN_FILE="$ToolchainFile" \
-DCMAKE_MAKE_PROGRAM="$AndroidNinjaExe" \
-G "Ninja" \
../../llvm-8.0.0.src

$AndroidCmakeExe --build .

 

And the full error output from the build is :

[186/1329] Creating export file for LLVMHello
FAILED: lib/Transforms/Hello/LLVMHello.exports
cmd.exe /C "cd /D C:\JStash\Projects\llvm\llvm_android_project\armeabi-v7a\lib\Transforms\Hello && echo "LLVM_8 {" > LLVMHello.exports && ( grep -q [[:alnum:]] C:/JStash/Projects/llvm/llvm-8.0.0.src/lib/Transforms/Hello/Hello.exports && echo "  global:" >> LLVMHello.exports || : ) && sed -e s/$/;/ -e "s/^/    /" < C:/JStash/Projects/llvm/llvm-8.0.0.src/lib/Transforms/Hello/Hello.exports >> LLVMHello.exports && echo "  local: *;" >> LLVMHello.exports && echo }; >> LLVMHello.exports"
':' is not recognized as an internal or external command,
operable program or batch file.
[195/1329] Configuring NATIVE LLVM...
FAILED: NATIVE/CMakeCache.txt
cmd.exe /C "cd /D C:\JStash\Projects\llvm\llvm_android_project\armeabi-v7a\NATIVE && C:\Users\jgiannone\AppData\Local\Android\Sdk\cmake\3.10.2.4988404\bin\cmake.exe -G Ninja -DCMAKE_MAKE_PROGRAM="C:\Users\jgiannone\AppData\Local/Android/Sdk/cmake/3.10.2.4988404/bin/ninja.exe" -DCMAKE_C_COMPILER=C:/Users/jgiannone/AppData/Local/Android/Sdk/ndk-bundle/toolchains/llvm/prebuilt/windows-x86_64/bin/clang.exe -DCMAKE_CXX_COMPILER=C:/Users/jgiannone/AppData/Local/Android/Sdk/ndk-bundle/toolchains/llvm/prebuilt/windows-x86_64/bin/clang++.exe C:/JStash/Projects/llvm/llvm-8.0.0.src -DLLVM_TARGET_IS_CROSSCOMPILE_HOST=TRUE -DLLVM_TARGETS_TO_BUILD="ARM" -DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD="" -DLLVM_DEFAULT_TARGET_TRIPLE="armv7a-linux-androideabi" -DLLVM_TARGET_ARCH="ARM" -DLLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN="OFF" -DCMAKE_BUILD_TYPE=Release"
-- The C compiler identification is Clang 8.0.7
-- The CXX compiler identification is Clang 8.0.7
-- The ASM compiler identification is Clang
-- Found assembler: C:/Users/jgiannone/AppData/Local/Android/Sdk/ndk-bundle/toolchains/llvm/prebuilt/windows-x86_64/bin/clang.exe
-- Check for working C compiler: C:/Users/jgiannone/AppData/Local/Android/Sdk/ndk-bundle/toolchains/llvm/prebuilt/windows-x86_64/bin/clang.exe
-- Check for working C compiler: C:/Users/jgiannone/AppData/Local/Android/Sdk/ndk-bundle/toolchains/llvm/prebuilt/windows-x86_64/bin/clang.exe -- broken
CMake Error at C:/Users/jgiannone/AppData/Local/Android/Sdk/cmake/3.10.2.4988404/share/cmake-3.10/Modules/CMakeTestCCompiler.cmake:52 (message):
  The C compiler

    "C:/Users/jgiannone/AppData/Local/Android/Sdk/ndk-bundle/toolchains/llvm/prebuilt/windows-x86_64/bin/clang.exe"

  is not able to compile a simple test program.

  It fails with the following output:

    Change Dir: C:/JStash/Projects/llvm/llvm_android_project/armeabi-v7a/NATIVE/CMakeFiles/CMakeTmp

    Run Build Command:"C:\Users\jgiannone\AppData\Local/Android/Sdk/cmake/3.10.2.4988404/bin/ninja.exe" "cmTC_43bcf"
    [1/2] Building C object CMakeFiles/cmTC_43bcf.dir/testCCompiler.c.obj
    [2/2] Linking C executable cmTC_43bcf.exe
    FAILED: cmTC_43bcf.exe
    cmd.exe /C "cd . && C:\Users\jgiannone\AppData\Local\Android\Sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\clang.exe    CMakeFiles/cmTC_43bcf.dir/testCCompiler.c.obj  -o cmTC_43bcf.exe -Wl,--out-implib,libcmTC_43bcf.dll.a -Wl,--major-image-version,0,--minor-image-version,0  -lkernel32 -luser32 -lgdi32 -lwinspool -lshell32 -lole32 -loleaut32 -luuid -lcomdlg32 -ladvapi32 && cd ."

    clang: error: unable to execute command: program not executable
    clang: error: linker command failed with exit code 1 (use -v to see invocation)
    ninja: build stopped: subcommand failed.

  CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
  CMakeLists.txt:39 (project)


-- Configuring incomplete, errors occurred!
See also "C:/JStash/Projects/llvm/llvm_android_project/armeabi-v7a/NATIVE/CMakeFiles/CMakeOutput.log".
See also "C:/JStash/Projects/llvm/llvm_android_project/armeabi-v7a/NATIVE/CMakeFiles/CMakeError.log".

ninja: build stopped: subcommand failed.

I'm kinda stumped as to what's going on...

[Justin Giannone via llvm-dev]

Although there didn't seem to be any interest in my thread, I figured I should still update with my partial success.  I've managed to get LLVM to build with Android NDK and have put together scripts to encapsulate the necessary commands.  See https://github.com/Jman420/llvm_for_android for scripts and instructions.

For some reason the '*.exports' files do not seem to get generated correctly.  They end up with double quoted lines (such as '"LLVM {"') which seem to be invalid format.  Unfortunately, I haven't been able to figure out where/what generates those files.  They seem to be generated by the actual compiler since those files don't exist until I execute 'cmake --build . --target install'.