This patch pulls google/benchmark v1.4.1 into the LLVM tree so that any project could use it for benchmark generation. A dummy benchmark is added to llvm/benchmarks/DummyYAML.cpp to validate the correctness of the build process.
The current version does not utilize LLVM LNT and LLVM CMake infrastructure, but that might be sufficient for most users. Two introduced CMake variables:
- LLVM_INCLUDE_BENCHMARKS (ON by default) generates benchmark targets
- LLVM_BUILD_BENCHMARKS (OFF by default) adds generated benchmark targets to the list of default LLVM targets (i.e. if ON benchmarks will be built upon standard build invocation, e.g. ninja or make with no specific targets)
List of modifications:
- BENCHMARK_ENABLE_TESTING is disabled
- BENCHMARK_ENABLE_EXCEPTIONS is disabled
- BENCHMARK_ENABLE_INSTALL is disabled
- BENCHMARK_ENABLE_GTEST_TESTS is disabled
- BENCHMARK_DOWNLOAD_DEPENDENCIES is disabled
Original discussion can be found here: http://lists.llvm.org/pipermail/llvm-dev/2018-August/125023.html
That seems to require CMake 3.6 (https://stackoverflow.com/questions/42167432/cmake-list-does-not-recognize-sub-command-filter).
But our requirement is only 3.4.3 (https://llvm.org/docs/GettingStarted.html).