1 files changed, 138 insertions, 0 deletions
diff --git a/lib/libcxx/benchmarks/filesystem.bench.cpp b/lib/libcxx/benchmarks/filesystem.bench.cpp
new file mode 100644
index 00000000000..f7949a163a7
--- /dev/null
+++ b/lib/libcxx/benchmarks/filesystem.bench.cpp
@@ -0,0 +1,138 @@
+#include <experimental/filesystem>
+
+#include "benchmark/benchmark_api.h"
+#include "GenerateInput.hpp"
+#include "test_iterators.h"
+
+namespace fs = std::experimental::filesystem;
+
+static const size_t TestNumInputs = 1024;
+
+
+template <class GenInputs>
+void BM_PathConstructString(benchmark::State &st, GenInputs gen) {
+  using namespace fs;
+  const auto in = gen(st.range(0));
+  path PP;
+  for (auto& Part : in)
+    PP /= Part;
+  benchmark::DoNotOptimize(PP.native().data());
+  while (st.KeepRunning()) {
+    const path P(PP.native());
+    benchmark::DoNotOptimize(P.native().data());
+  }
+}
+BENCHMARK_CAPTURE(BM_PathConstructString, large_string,
+  getRandomStringInputs)->Arg(TestNumInputs);
+
+
+template <class GenInputs>
+void BM_PathConstructCStr(benchmark::State &st, GenInputs gen) {
+  using namespace fs;
+  const auto in = gen(st.range(0));
+  path PP;
+  for (auto& Part : in)
+    PP /= Part;
+  benchmark::DoNotOptimize(PP.native().data());
+  while (st.KeepRunning()) {
+    const path P(PP.native().c_str());
+    benchmark::DoNotOptimize(P.native().data());
+  }
+}
+BENCHMARK_CAPTURE(BM_PathConstructCStr, large_string,
+  getRandomStringInputs)->Arg(TestNumInputs);
+
+
+template <template <class...> class ItType, class GenInputs>
+void BM_PathConstructIter(benchmark::State &st, GenInputs gen) {
+  using namespace fs;
+  using Iter = ItType<std::string::const_iterator>;
+  const auto in = gen(st.range(0));
+  path PP;
+  for (auto& Part : in)
+    PP /= Part;
+  auto Start = Iter(PP.native().begin());
+  auto End = Iter(PP.native().end());
+  benchmark::DoNotOptimize(PP.native().data());
+  benchmark::DoNotOptimize(Start);
+  benchmark::DoNotOptimize(End);
+  while (st.KeepRunning()) {
+    const path P(Start, End);
+    benchmark::DoNotOptimize(P.native().data());
+  }
+}
+template <class GenInputs>
+void BM_PathConstructInputIter(benchmark::State &st, GenInputs gen) {
+  BM_PathConstructIter<input_iterator>(st, gen);
+}
+template <class GenInputs>
+void BM_PathConstructForwardIter(benchmark::State &st, GenInputs gen) {
+  BM_PathConstructIter<forward_iterator>(st, gen);
+}
+BENCHMARK_CAPTURE(BM_PathConstructInputIter, large_string,
+  getRandomStringInputs)->Arg(TestNumInputs);
+BENCHMARK_CAPTURE(BM_PathConstructForwardIter, large_string,
+  getRandomStringInputs)->Arg(TestNumInputs);
+
+
+template <class GenInputs>
+void BM_PathIterateMultipleTimes(benchmark::State &st, GenInputs gen) {
+  using namespace fs;
+  const auto in = gen(st.range(0));
+  path PP;
+  for (auto& Part : in)
+    PP /= Part;
+  benchmark::DoNotOptimize(PP.native().data());
+  while (st.KeepRunning()) {
+    for (auto &E : PP) {
+      benchmark::DoNotOptimize(E.native().data());
+    }
+    benchmark::ClobberMemory();
+  }
+}
+BENCHMARK_CAPTURE(BM_PathIterateMultipleTimes, iterate_elements,
+  getRandomStringInputs)->Arg(TestNumInputs);
+
+
+template <class GenInputs>
+void BM_PathIterateOnce(benchmark::State &st, GenInputs gen) {
+  using namespace fs;
+  const auto in = gen(st.range(0));
+  path PP;
+  for (auto& Part : in)
+    PP /= Part;
+  benchmark::DoNotOptimize(PP.native().data());
+  while (st.KeepRunning()) {
+    const path P = PP.native();
+    for (auto &E : P) {
+      benchmark::DoNotOptimize(E.native().data());
+    }
+    benchmark::ClobberMemory();
+  }
+}
+BENCHMARK_CAPTURE(BM_PathIterateOnce, iterate_elements,
+  getRandomStringInputs)->Arg(TestNumInputs);
+
+template <class GenInputs>
+void BM_PathIterateOnceBackwards(benchmark::State &st, GenInputs gen) {
+  using namespace fs;
+  const auto in = gen(st.range(0));
+  path PP;
+  for (auto& Part : in)
+    PP /= Part;
+  benchmark::DoNotOptimize(PP.native().data());
+  while (st.KeepRunning()) {
+    const path P = PP.native();
+    const auto B = P.begin();
+    auto I = P.end();
+    while (I != B) {
+      --I;
+      benchmark::DoNotOptimize(*I);
+    }
+    benchmark::DoNotOptimize(*I);
+  }
+}
+BENCHMARK_CAPTURE(BM_PathIterateOnceBackwards, iterate_elements,
+  getRandomStringInputs)->Arg(TestNumInputs);
+
+BENCHMARK_MAIN()