[Bug] Cannot find -lxml2 when linking libtvm.so on Ubuntu 22.04 (WSL2)

[930727fre]

Expected behavior

TVM should successfully compile and link libtvm.so without missing -lxml2.

Actual behavior

The build fails with a linker error stating that -lxml2 cannot be found:

[100%] Building CXX object CMakeFiles/tvm_objs.dir/src/target/llvm/llvm_instance.cc.o
[100%] Building CXX object CMakeFiles/tvm_objs.dir/src/target/llvm/llvm_module.cc.o
/home/fre930727/tvm/src/target/tag.cc: In function ‘void __static_initialization_and_destruction_0(int, int)’:
/home/fre930727/tvm/src/target/tag.cc:462:1: note: variable tracking size limit exceeded with ‘-fvar-tracking-assignments’, retrying without
  462 | }  // namespace tvm
      | ^
[100%] Built target tvm_objs
[100%] Linking CXX shared library libtvm.so
[100%] Linking CXX shared library libtvm_allvisible.so
/usr/bin/ld: cannot find -lxml2: /usr/bin/ld: cannot find -lxml2: No such file or directory
No such file or directory
collect2: error: ld returned 1 exit status
collect2: error: ld returned 1 exit status
gmake[2]: *** [CMakeFiles/tvm.dir/build.make:1408: libtvm.so] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:208: CMakeFiles/tvm.dir/all] Error 2
gmake[1]: *** Waiting for unfinished jobs....
gmake[2]: *** [CMakeFiles/tvm_allvisible.dir/build.make:1408: libtvm_allvisible.so] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:309: CMakeFiles/tvm_allvisible.dir/all] Error 2
gmake: *** [Makefile:136: all] Error 2

Environment

• OS: Ubuntu 22.04 (WSL2)
• CPU: Intel i5-12400
• TVM Version: 12e72c2

Steps to reproduce

1. Follow the instructions in the [TVM installation guide](https://tvm.apache.org/docs/install/from_source.html).

2. Execute the following shell script:

   # make sure to start with a fresh environment
   conda env remove -n tvm-build-venv
   # create the conda environment with build dependency
   conda create -n tvm-build-venv -c conda-forge \
       "llvmdev>=15" \
       "cmake>=3.24" \
       git \
       python=3.11
   # enter the build environment
   conda activate tvm-build-venv

   git clone --recursive https://github.com/apache/tvm tvm
   

   cd tvm
   rm -rf build && mkdir build && cd build
   # Specify the build configuration via CMake options
   cp ../cmake/config.cmake .

   # controls default compilation flags (Candidates: Release, Debug, RelWithDebInfo)
   echo "set(CMAKE_BUILD_TYPE RelWithDebInfo)" >> config.cmake
   
   # LLVM is a must dependency for compiler end
   echo "set(USE_LLVM \"llvm-config --ignore-libllvm --link-static\")" >> config.cmake
   echo "set(HIDE_PRIVATE_SYMBOLS ON)" >> config.cmake
   
   # GPU SDKs, turn on if needed
   echo "set(USE_CUDA   OFF)" >> config.cmake
   echo "set(USE_METAL  OFF)" >> config.cmake
   echo "set(USE_VULKAN OFF)" >> config.cmake
   echo "set(USE_OPENCL OFF)" >> config.cmake
   
   # cuBLAS, cuDNN, cutlass support, turn on if needed
   echo "set(USE_CUBLAS OFF)" >> config.cmake
   echo "set(USE_CUDNN  OFF)" >> config.cmake
   echo "set(USE_CUTLASS OFF)" >> config.cmake

   cmake .. && cmake --build . --parallel $(nproc)

3. The build fails with the above linker error.

Troubleshooting Attempts

• Added debugging options:

  echo "set(CMAKE_BUILD_TYPE Debug)" >> config.cmake
  echo "set(USE_ALTERNATIVE_LINKER OFF)" >> config.cmake
  echo "set(USE_LIBBACKTRACE On)" >> config.cmake
  

• Installed libxml2 via Conda:

  conda install -c conda-forge libxml2
  

Questions

• Is libxml2 required to be installed via apt rather than Conda for TVM to find it?
• Are there specific CMake flags I should set to properly link against libxml2?
• Any recommendations for debugging linker issues in this context?

Triage

• needs-triage

Any help would be greatly appreciated. Thanks!

[ShihengCao]

hello, i encoutered the same problem and i resolved it. My solution is use the path of xml2 to replace the -lxml2 in link.txt.
use bash:~$ find $CONDA_PREFIX/lib -name "libxml2*" to get the path of lxml2.
I get a path like /$HOME/miniconda3/envs/tvm-build-venv/lib/libxml2.so, then use "/$HOME/miniconda3/envs/tvm-build-venv/lib/libxml2.so" to replace "-lxml2" in tvm/build/CMakeFiles/tvm_allvisible.dir/link.txt and tvm/build/CMakeFiles/tvm.dir/link.txt.
Hope this can work for you.