Toolchains

By default, clang-build provides an llvm-clang toolchain (see the LLVM class in clang_build/toolchain.py). But it also allows you to use custom ones, by passing passing the toolchain command line argument, i.e. clang-build ... --toolchain /path/to/your_toolchain.py. The Python-file which you pass to clang-build must define a function with the following signature:

import clang_build

def get_toolchain(environment) -> clang_build.toolchain.Toolchain:
   toolchain = clang_build.toolchain.Toolchain()
   #...
   return toolchain

For a working example look at tests/toolchains/emscripten-toolchain.py.

The important part is the signature. You should derive from the Toolchain base class and override the given defaults as needed:

• the build platform (on which clang-build is being run), e.g.
  • windows
  • osx
  • linux
• the host platform (on which the build results may be run), e.g.
  • windows
  • osx
  • linux
  • web / browser
• the host architecture (on which to run the built binaries), e.g.
  • x86
  • GPU
  • web / wasm
• a list of supported C-dialect languages, e.g.
  • C
  • C++
  • CUDA-C
  • CUDA-C++
  • OpenCL
  • Objective-C
  • Objective-C++
• default compile and link flags for all target types (executable, ...) for all build types (debug, ...) for the available languages for the given combination of build and host platform