How to use custom build of clang (and modules)

[githubuser6000]

Hi all. I have a custom build of clang that I'd like to use with emcc. I set EMCC_LLVM_ROOT to the build directory of clang I compiled from source and emcc --check seems to return OK.

Now I am trying to use a testing version of clang compiler with C++ modules support. How do I continue using those features in my code but build a wasm target?

I seemingly am running into a bunch of compiler errors due to missing headers with a simple C++ module project.

[sbc100]

The version of clang that comes with emscripten/emsdk is basically tip-of-tree so you should not need to use a custom version just to get module support (i.e. the version of clang we ship should have all the latest module support).

However, emscripten itself still doesn't have integrated module support. See #21987 for example.

However if you do want to use your down version of clang when EM_LLVM_ROOT should certainly work. (Note that its EM_LLVM_ROOT not EMCC_LLVM_ROOT). Can you share exactly what errors you are seeing?