Check for invalid projects passed in LLVM_ENABLE_PROJECTS

[mehdi_amini]

Summary

This is catching misconfiguration. For example one of my automation
had a typo running -DLLVM_ENABLE_PROJECTS=nlir and it was just
silently ignored. Instead, an error will now be displayed.

[beanz]

LGTM

[lebedev.ri]

CMake Error at CMakeLists.txt:76 (MESSAGE):
  all isn't a know project:
  clang;clang-tools-extra;compiler-rt;cross-project-tests;libc;libclc;libcxx;libcxxabi;libunwind;lld;lldb;mlir;openmp;parallel-libs;polly;pstl;flang;llvm

[mehdi_amini]

In D110016#3007854, @lebedev.ri wrote:

CMake Error at CMakeLists.txt:76 (MESSAGE):
  all isn't a know project:

Of course it isn't!

Thanks for the revert

[bondhugula]

llvm/CMakeLists.txt

76

know -> known

76

There shouldn't be a dangling colon at the end.

[MaskRay]

llvm/CMakeLists.txt

67

I added debuginfo-tests in 4b80f0125adc876c8ef325f1c0ace4af023f2264

[mehdi_amini]

llvm/CMakeLists.txt

67

Wasn't this renamed to cross-project-tests?

[mehdi_amini]

llvm/CMakeLists.txt

67

See 1364750dadbb56032ef73b4d0d8cbc88a51392da

Move debuginfo-test into a subdirectory of a new top-level directory,
called cross-project-tests. The new name replaces "debuginfo-test" as an
LLVM project enabled via LLVM_ENABLE_PROJECTS.

[MaskRay]

llvm/CMakeLists.txt

67

Ah, my LLVM_ENABLE_PROJECTS had debuginfo-tests so my build was broken.

My debuginfo-tests/ was not empty because there were many __pycache__ .pyc files...

I'll revert the commit. Sorry

[thakis]

This is a problem for us (chromium). We inject an extra target at the cmake level and then pass that to LLVM_ENABLE_PROJECTS. That used to work fine, but now it's rejected.

How should we proceed?

• Put this check behind a (default-on) option and turn it off for us
• Add a setting of valid extra project names that's default-empty
• Your idea here

[mehdi_amini]

In D110016#3010053, @thakis wrote:

This is a problem for us (chromium). We inject an extra target at the cmake level and then pass that to LLVM_ENABLE_PROJECTS. That used to work fine, but now it's rejected.

I didn't quite get the "inject" part?

How should we proceed?

• Put this check behind a (default-on) option and turn it off for us
• Add a setting of valid extra project names that's default-empty

Any of these could work.

• Your idea here

Actually we already have a flag for that: -DLLVM_EXTERNAL_PROJECTS which is intended to be used to declare projects that aren't "known" (see https://llvm.org/docs/CMake.html )
Aren't you able to use this?

[thakis]

In D110016#3010136, @mehdi_amini wrote:

In D110016#3010053, @thakis wrote:

This is a problem for us (chromium). We inject an extra target at the cmake level and then pass that to LLVM_ENABLE_PROJECTS. That used to work fine, but now it's rejected.

I didn't quite get the "inject" part?

Like so: https://source.chromium.org/chromium/chromium/src/+/main:tools/clang/scripts/build.py;l=192?q=chrometools&ss=chromium

Any of these could work.

Cool, did the first version in 55f0b337087136554122f942fea951a357bc4a49.

Actually we already have a flag for that: -DLLVM_EXTERNAL_PROJECTS which is intended to be used to declare projects that aren't "known" (see https://llvm.org/docs/CMake.html )
Aren't you able to use this?

We tried it a while ago and ran into a bunch of issues, see https://bugs.chromium.org/p/chromium/issues/detail?id=962988&q=LLVM_EXTERNAL_PROJECTS&can=2

[mehdi_amini]

In D110016#3010192, @thakis wrote:

Actually we already have a flag for that: -DLLVM_EXTERNAL_PROJECTS which is intended to be used to declare projects that aren't "known" (see https://llvm.org/docs/CMake.html )
Aren't you able to use this?

We tried it a while ago and ran into a bunch of issues, see https://bugs.chromium.org/p/chromium/issues/detail?id=962988&q=LLVM_EXTERNAL_PROJECTS&can=2

Seems like this was fixed a couple of weeks after the last comment in this bug? https://reviews.llvm.org/D62289

[thakis]

Seems like this was fixed a couple of weeks after the last comment in this bug? https://reviews.llvm.org/D62289

We're trying again: https://chromium-review.googlesource.com/c/chromium/src/+/3172772 If it works out, we can remove LLVM_CHECK_ENABLED_PROJECTS again.

[jaopaulolc]

llvm/CMakeLists.txt

71

Shouldn't LLVM_EXTERNAL_PROJECTS be appended to LLVM_KNOWN_PROJECTS ?

Otherwise it would fail when a external project is configure with -DLLVM_EXTERNAL_PROJECTS=foo-project -DLLVM_ENABLE_PROJECTS=foo.

If so, the loop enabling the projects should just loop on LLVM_KNOWN_PROJECTS.

[mehdi_amini]

llvm/CMakeLists.txt

71

From what I read line 129, you don't use LLVM_ENABLE_PROJECTS for external projects.

[jaopaulolc]

llvm/CMakeLists.txt

71

You are right, external projects should not be passed in LLVM_ENABLE_PROJECTS. Thanks for pointing that out.

llvm/CMakeLists.txt

if (NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
   message(STATUS "No build type selected, default to Debug")
   set(CMAKE_BUILD_TYPE "Debug" CACHE STRING "Build type (default Debug)" FORCE)
 endif()
 
 # Side-by-side subprojects layout: automatically set the
 # LLVM_EXTERNAL_${project}_SOURCE_DIR using LLVM_ALL_PROJECTS
 # This allows an easy way of setting up a build directory for llvm and another
 # one for llvm+clang+... using the same sources.
 set(LLVM_ALL_PROJECTS "clang;clang-tools-extra;compiler-rt;cross-project-tests;libc;libclc;libcxx;libcxxabi;libunwind;lld;lldb;mlir;openmp;parallel-libs;polly;pstl")
 # The flang project is not yet part of "all" projects (see C++ requirements)
 set(LLVM_EXTRA_PROJECTS "flang")
 # List of all known projects in the mono repo
 set(LLVM_KNOWN_PROJECTS "${LLVM_ALL_PROJECTS};${LLVM_EXTRA_PROJECTS}")
 set(LLVM_ENABLE_PROJECTS "" CACHE STRING
   "Semicolon-separated list of projects to build (${LLVM_KNOWN_PROJECTS}), or \"all\".")
+foreach(proj ${LLVM_ENABLE_PROJECTS})
+  if (NOT proj STREQUAL "all" AND NOT proj STREQUAL "llvm" AND NOT "${proj}" IN_LIST LLVM_KNOWN_PROJECTS)
+     MESSAGE(FATAL_ERROR "${proj} isn't a know project: ${LLVM_KNOWN_PROJECTS}")
+  endif()
+endforeach()
+
 if( LLVM_ENABLE_PROJECTS STREQUAL "all" )
   set( LLVM_ENABLE_PROJECTS ${LLVM_ALL_PROJECTS})
 endif()
 
 if ("flang" IN_LIST LLVM_ENABLE_PROJECTS)
   if (NOT "mlir" IN_LIST LLVM_ENABLE_PROJECTS)
     message(STATUS "Enabling MLIR as a dependency to flang")
     list(APPEND LLVM_ENABLE_PROJECTS "mlir")