Does LLVM_ENABLE_PROJECTS=compiler-rt need to be adapted on win

[GkvJwa]

I used the main branch and noticed the following warning(#124016)

-DLLVM_ENABLE_PROJECTS="clang;clang-tools-extra;lld;compiler-rt"

CMake Warning at CMakeLists.txt:189 (message):
  Using LLVM_ENABLE_PROJECTS=compiler-rt is deprecated now, and will become a
  fatal error in the LLVM 21 release.  Please use
  -DLLVM_ENABLE_RUNTIMES=compiler-rt or see the instructions at
  https://compiler-rt.llvm.org/ for building the runtimes.

So I maked with -DLLVM_ENABLE_RUNTIMES="compiler-rt"

However, just using LLVM_ENABLE_RUNTIMES will cause the following problems

-DLLVM_ENABLE_PROJECTS="clang;clang-tools-extra;lld" -DLLVM_ENABLE_RUNTIMES="compiler-rt"

-- clang project is enabled
-- clang-tools-extra project is enabled
-- compiler-rt project is disabled
-- cross-project-tests project is disabled

This is due to ${proj}(compiler-rt) is not in LLVM_ENABLE_PROJECTS, The project will not be generated

llvm-project/llvm/CMakeLists.txt

Lines 260 to 270 in 7138397

	set(LLVM_ENABLE_PROJECTS_USED OFF CACHE BOOL "")
	mark_as_advanced(LLVM_ENABLE_PROJECTS_USED)
	if (LLVM_ENABLE_PROJECTS_USED OR NOT LLVM_ENABLE_PROJECTS STREQUAL "")
	set(LLVM_ENABLE_PROJECTS_USED ON CACHE BOOL "" FORCE)
	foreach(proj ${LLVM_KNOWN_PROJECTS} ${LLVM_EXTERNAL_PROJECTS})
	string(TOUPPER "${proj}" upper_proj)
	string(REGEX REPLACE "-" "_" upper_proj ${upper_proj})
	if ("${proj}" IN_LIST LLVM_ENABLE_PROJECTS)
	message(STATUS "${proj} project is enabled")
	set(SHOULD_ENABLE_PROJECT TRUE)

Does LLVM_ENABLE_PROJECTS=compiler-rt need to be adapted or is there any other command?

@petrhosek Can you help me with this problem if you have time?

[efriedma-quic]

I think that's working as expected; "compiler-rt project is disabled" just indicates you didn't pass it to LLVM_ENABLE_PROJECTS. compiler-rt should get built as a runtime.

[petrhosek]

I think that's working as expected; "compiler-rt project is disabled" just indicates you didn't pass it to LLVM_ENABLE_PROJECTS. compiler-rt should get built as a runtime.

That's correct, compiler-rt should be built as a runtime, not as a project. The difference is that projects use the host toolchain whereas runtimes use the just built Clang toolchain.

[GkvJwa]

Got it, thanks