CMake¶

CMake and language servers¶

CMake works well with the clangd language server. It can automatially generate the compile_commands.json file, which is used by clangd to provide code completion, diagnostics, and other features.

The compile_commands.json contains the exact comiler call for all translation units of the project.

To generate the compile_commands.json file, use the following CMake option:

-DCMAKE_EXPORT_COMPILE_COMMANDS=ON

Ccache¶

To use Ccache (compiler cache) with CMake, one can set the following environment or CMake variable:

CMAKE_<LANG>_COMPILER_LAUNCHER=ccache

Supported languages are the following: C, CXX, Fortran, CUDA, HIP.

Project-wide setting¶

For a project-wide setting, one can add the following to the CMakeLists.txt file:

find_program(CCACHE_PROGRAM ccache)
if(CCACHE_PROGRAM)
  set(CMAKE_<LANG>_COMPILER_LAUNCHER "${CCACHE_PROGRAM}")
endif()

Target-specific setting¶

For a specific target, the <LANG>_COMPILER_LAUNCHER property can be set:

find_program(CCACHE_PROGRAM ccache)
if(CCACHE_PROGRAM)
  set_target_properties(<TARGET> PROPERTIES <LANG>_COMPILER_LAUNCHER ${CCACHE_PROGRAM})
endif()