Cherrypick the upstream fix commit a77d5f7 onto llvm/utils/benchmark
and libcxx/utils/google-benchmark.
This fixes LLVM's 32-bit RISC-V compilation, and the issues
mentioned in https://github.com/google/benchmark/pull/955
An additional cherrypick of ecc1685 fixes some minor formatting
issues introduced by the preceding commit.
Differential Revision: https://reviews.llvm.org/D78084
This is a cherrypick of D64237 onto llvm/utils/benchmark and
libcxx/utils/google-benchmark.
Differential Revision: https://reviews.llvm.org/D65142
llvm-svn: 366868
Summary:
This patch does the following:
1. Checks in a copy of the Google Benchmark library into the libc++ repo under `utils/google-benchmark`.
2. Teaches libc++ how to build Google Benchmark against both (A) in-tree libc++ and (B) the platforms native STL.
3. Allows performance benchmarks to be built as part of the libc++ build.
Building the benchmarks (and Google Benchmark) is off by default. It must be enabled using the CMake option `-DLIBCXX_INCLUDE_BENCHMARKS=ON`. When this option is enabled the tests under `libcxx/benchmarks` can be built using the `libcxx-benchmarks` target.
On Linux platforms where libstdc++ is the default STL the CMake option `-DLIBCXX_BUILD_BENCHMARKS_NATIVE_STDLIB=ON` can be used to build each benchmark test against libstdc++ as well. This is useful for comparing performance between standard libraries.
Support for benchmarks is currently very minimal. They must be manually run by the user and there is no mechanism for detecting performance regressions.
Known Issues:
* `-DLIBCXX_INCLUDE_BENCHMARKS=ON` is only supported for Clang, and not GCC, since the `-stdlib=libc++` option is needed to build Google Benchmark.
Reviewers: danalbert, dberlin, chandlerc, mclow.lists, jroelofs
Subscribers: chandlerc, dberlin, tberghammer, danalbert, srhines, hfinkel
Differential Revision: https://reviews.llvm.org/D22240
llvm-svn: 276049
Luís Marques