[libcxx] Passthrough the necessary CMake variables to benchmarks

[petrhosek]

This addresses the issue uncovered by #115361. Previously, we weren't building benchmarks in many cases due to the following block:

llvm-project/libcxx/CMakeLists.txt

Lines 162 to 172 in e589496

	if (WIN32 OR MINGW OR ANDROID OR ${CMAKE_SYSTEM_NAME} MATCHES "AIX"
	OR NOT LIBCXX_ENABLE_LOCALIZATION
	OR NOT LIBCXX_ENABLE_THREADS
	OR NOT LIBCXX_ENABLE_FILESYSTEM
	OR NOT LIBCXX_ENABLE_RANDOM_DEVICE
	OR NOT LIBCXX_ENABLE_EXCEPTIONS
	OR NOT LIBCXX_ENABLE_RTTI)
	set(_include_benchmarks OFF)
	else()
	set(_include_benchmarks ON)
	endif()

We need to passthrough the necessary variables into the benchmarks subbuild and use correct syntax.

[llvmbot]

@llvm/pr-subscribers-libcxx

Author: Petr Hosek (petrhosek)

Changes

This addresses the issue uncovered by #115361. Previously, we weren't building benchmarks in many cases due to the following block:

llvm-project/libcxx/CMakeLists.txt

Lines 162 to 172 in e589496

	if (WIN32 OR MINGW OR ANDROID OR ${CMAKE_SYSTEM_NAME} MATCHES "AIX"
	OR NOT LIBCXX_ENABLE_LOCALIZATION
	OR NOT LIBCXX_ENABLE_THREADS
	OR NOT LIBCXX_ENABLE_FILESYSTEM
	OR NOT LIBCXX_ENABLE_RANDOM_DEVICE
	OR NOT LIBCXX_ENABLE_EXCEPTIONS
	OR NOT LIBCXX_ENABLE_RTTI)
	set(_include_benchmarks OFF)
	else()
	set(_include_benchmarks ON)
	endif()

We need to passthrough the necessary variables into the benchmarks subbuild and use correct syntax.

---

Full diff: https://github.com/llvm/llvm-project/pull/116644.diff

1 Files Affected:

• (modified) libcxx/test/benchmarks/CMakeLists.txt (+4-3)

diff --git a/libcxx/test/benchmarks/CMakeLists.txt b/libcxx/test/benchmarks/CMakeLists.txt
index b5a4aae82c06ab..b0fe600623d964 100644
--- a/libcxx/test/benchmarks/CMakeLists.txt
+++ b/libcxx/test/benchmarks/CMakeLists.txt
@@ -35,13 +35,14 @@ ExternalProject_Add(google-benchmark
         SOURCE_DIR ${LLVM_THIRD_PARTY_DIR}/benchmark
         INSTALL_DIR ${CMAKE_CURRENT_BINARY_DIR}/google-benchmark
         CMAKE_CACHE_ARGS
-          -DCMAKE_C_COMPILER:STRING=${CMAKE_C_COMPILER}
-          -DCMAKE_CXX_COMPILER:STRING=${CMAKE_CXX_COMPILER}
+          -DCMAKE_C_COMPILER:FILEPATH=${CMAKE_C_COMPILER}
+          -DCMAKE_CXX_COMPILER:FILEPATH=${CMAKE_CXX_COMPILER}
+          -DCMAKE_MAKE_PROGRAM:FILEPATH=${CMAKE_MAKE_PROGRAM}
           -DCMAKE_BUILD_TYPE:STRING=RELEASE
           -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR>
           -DCMAKE_CXX_FLAGS:STRING=${BENCHMARK_COMPILE_FLAGS}
           -DBENCHMARK_USE_LIBCXX:BOOL=ON
           -DBENCHMARK_ENABLE_TESTING:BOOL=OFF
-          -DBENCHMARK_CXX_LIBRARIES:STRING="${BENCHMARK_CXX_LIBRARIES}")
+          -DBENCHMARK_CXX_LIBRARIES:STRING=${BENCHMARK_CXX_LIBRARIES})
 
 add_dependencies(cxx-test-depends google-benchmark)

[PiJoules]

ping is this ready to land?

[petrhosek]

ping is this ready to land?

I need an approval from one of the libc++ reviewers.

[petrhosek]

I'm going to land this change because our builders have been broken since #115361 landed and I'm not getting any response from @ldionne.

[ldionne]

This LGTM. Sorry for the delay, I am at a C++ Committee Meeting this week and things are much more hectic than usual over here (stuff rushing for the C++26 deadline), so I haven't had time to do any code review.