Pull google/benchmark library to the LLVM tree
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
Reviewed by: dberris, lebedev.ri
Subscribers: ilya-biryukov, ioeric, EricWF, lebedev.ri, srhines,
dschuff, mgorny, krytarowski, fedor.sergeev, mgrang, jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D50894
llvm-svn: 340809
diff --git a/llvm/utils/benchmark/src/arraysize.h b/llvm/utils/benchmark/src/arraysize.h
new file mode 100644
index 0000000..51a50f2
--- /dev/null
+++ b/llvm/utils/benchmark/src/arraysize.h
@@ -0,0 +1,33 @@
+#ifndef BENCHMARK_ARRAYSIZE_H_
+#define BENCHMARK_ARRAYSIZE_H_
+
+#include "internal_macros.h"
+
+namespace benchmark {
+namespace internal {
+// The arraysize(arr) macro returns the # of elements in an array arr.
+// The expression is a compile-time constant, and therefore can be
+// used in defining new arrays, for example. If you use arraysize on
+// a pointer by mistake, you will get a compile-time error.
+//
+
+// This template function declaration is used in defining arraysize.
+// Note that the function doesn't need an implementation, as we only
+// use its type.
+template <typename T, size_t N>
+char (&ArraySizeHelper(T (&array)[N]))[N];
+
+// That gcc wants both of these prototypes seems mysterious. VC, for
+// its part, can't decide which to use (another mystery). Matching of
+// template overloads: the final frontier.
+#ifndef COMPILER_MSVC
+template <typename T, size_t N>
+char (&ArraySizeHelper(const T (&array)[N]))[N];
+#endif
+
+#define arraysize(array) (sizeof(::benchmark::internal::ArraySizeHelper(array)))
+
+} // end namespace internal
+} // end namespace benchmark
+
+#endif // BENCHMARK_ARRAYSIZE_H_