[GitHub] [tvm] lhez opened a new issue #9173: [Bug] [CMake] libtvm_runtime and cpp rpc won't build with NDK 23

[GitBox <gi...@apache.org>]

lhez opened a new issue #9173:
URL: https://github.com/apache/tvm/issues/9173


   NDK 23 seems to make some major changes from previous releases - it removes all gcc related components and `ld.gold`. This causes two issues when building with NDK 23.
   
   First, `libgcc` is added in the root [`CMakeLists.txt`](https://github.com/apache/tvm/blob/main/CMakeLists.txt#L228),
   
   ```
   if(BUILD_FOR_ANDROID)
     # EmuTLS on Android is in libgcc. Without it linked in, libtvm_runtime.so
     # won't load on Android due to missing __emutls_XXX symbols.
     list(APPEND TVM_RUNTIME_LINKER_LIBS "gcc")
   endif()
   ```
   This will result in following linker error because `libgcc` has been removed from NDK 23 (instead `libclang_rt.builtins-aarch64-android.a` is used)
   
   ```
   ld: error: unable to find library -lgcc
   ```
   
   This can be reproduced with the following commands,
   
   ```
   cmake -DCMAKE_TOOLCHAIN_FILE=/ndk/23.0.7599858/build/cmake/android.toolchain.cmake -DANDROID_ABI=arm64-v8a -DANDROID_PLATFORM=28 -DANDROID_STL=c++_static -DUSE_CPP_RPC=ON -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -G Ninja ..
   ninja tvm_rpc
   ```
   
   Linker will fail with `libtvm_runtime.so`. This can be fixed by disabling `libgcc` for NDK is 23. I am not sure about the TLS functions - but `tvm_rpc` runs fine with NDK 23 for me when `libgcc` is removed.
   
   Second, when OpenCL is enabled, `tvm_rpc` (the cpp rpc) will use `ld.gold` as the linker. This is specified in `tvm_rpc`'s [`CMakeLists.txt`](https://github.com/apache/tvm/blob/main/apps/cpp_rpc/CMakeLists.txt#L35),
   
   ```
   if(USE_OPENCL)
     if (ANDROID_ABI)
       set_property(TARGET tvm_rpc PROPERTY LINK_FLAGS -fuse-ld=gold)
     endif()
   endif()
   ```
   
   Since `ld.gold` is removed from NDK 23, Clang seems to call host `ld.gold`, resulting in failure
   
   ```
   /usr/bin/ld.gold: --no-rosegment: unknown option
   /usr/bin/ld.gold: use the --help option for usage information
   ```
   
   This can be reproduced by adding OpenCL,
   
   ```
   cmake -DCMAKE_TOOLCHAIN_FILE=/ndk/23.0.7599858/build/cmake/android.toolchain.cmake -DANDROID_ABI=arm64-v8a -D
   ANDROID_PLATFORM=28 -DANDROID_STL=c++_static -DUSE_CPP_RPC=ON -DUSE_OPENCL=ON -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -G Ninja ..
   ninja tvm_rpc
   ```
   
   Similarly, this can be fixed by disabling `ld.gold` for NDK 23.


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