Add `RegisterBenchmark(name, func, args...)` for creating/registering benchmarks. (#259)

* Add RegisterBenchmark

* fix test inputs

* fix UB caused by unitialized value

* Add RegisterBenchmark

* fix test inputs

* fix UB caused by unitialized value

* Work around GCC 4.6/4.7/4.8 bug

2 files changed, 150 insertions, 0 deletions

diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index aeb720a..3b8f7c9 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -45,6 +45,9 @@ add_test(donotoptimize_test donotoptimize_test --benchmark_min_time=0.01)
 compile_benchmark_test(fixture_test)
 add_test(fixture_test fixture_test --benchmark_min_time=0.01)
 
+compile_benchmark_test(register_benchmark_test)
+add_test(register_benchmark_test register_benchmark_test --benchmark_min_time=0.01)
+
 compile_benchmark_test(map_test)
 add_test(map_test map_test --benchmark_min_time=0.01)
 
diff --git a/test/register_benchmark_test.cc b/test/register_benchmark_test.cc
new file mode 100644
index 0000000..f11c5ea
--- /dev/null
+++ b/test/register_benchmark_test.cc
@@ -0,0 +1,147 @@
+
+#undef NDEBUG
+#include "benchmark/benchmark.h"
+#include "../src/check.h" // NOTE: check.h is for internal use only!
+#include <cassert>
+#include <vector>
+
+namespace {
+
+class TestReporter : public benchmark::ConsoleReporter {
+public:
+  virtual void ReportRuns(const std::vector<Run>& report) {
+    all_runs_.insert(all_runs_.end(), begin(report), end(report));
+    ConsoleReporter::ReportRuns(report);
+  }
+
+  std::vector<Run> all_runs_;
+};
+
+struct TestCase {
+  std::string name;
+  const char* label;
+  TestCase(const char* xname) : name(xname), label(nullptr) {}
+  TestCase(const char* xname, const char* xlabel)
+    : name(xname), label(xlabel) {}
+
+  typedef benchmark::BenchmarkReporter::Run Run;
+
+  void CheckRun(Run const& run) const {
+    CHECK(name == run.benchmark_name) << "expected " << name
+                                      << " got " << run.benchmark_name;
+    if (label) {
+      CHECK(run.report_label == label) << "expected " << label
+                                       << " got " << run.report_label;
+    } else {
+      CHECK(run.report_label == "");
+    }
+  }
+};
+
+std::vector<TestCase> ExpectedResults;
+
+int AddCases(std::initializer_list<TestCase> const& v) {
+  for (auto N : v) {
+    ExpectedResults.push_back(N);
+  }
+  return 0;
+}
+
+#define CONCAT(x, y) CONCAT2(x, y)
+#define CONCAT2(x, y) x##y
+#define ADD_CASES(...) \
+int CONCAT(dummy, __LINE__) = AddCases({__VA_ARGS__})
+
+}  // end namespace
+
+typedef benchmark::internal::Benchmark* ReturnVal;
+
+//----------------------------------------------------------------------------//
+// Test RegisterBenchmark with no additional arguments
+//----------------------------------------------------------------------------//
+void BM_function(benchmark::State& state) { while (state.KeepRunning()) {} }
+BENCHMARK(BM_function);
+ReturnVal dummy = benchmark::RegisterBenchmark(
+    "BM_function_manual_registration",
+     BM_function);
+ADD_CASES({"BM_function"}, {"BM_function_manual_registration"});
+
+//----------------------------------------------------------------------------//
+// Test RegisterBenchmark with additional arguments
+// Note: GCC <= 4.8 do not support this form of RegisterBenchmark because they
+//       reject the variadic pack expansion of lambda captures.
+//----------------------------------------------------------------------------//
+#ifndef BENCHMARK_HAS_NO_VARIADIC_REGISTER_BENCHMARK
+
+void BM_extra_args(benchmark::State& st, const char* label) {
+  while (st.KeepRunning()) {}
+  st.SetLabel(label);
+}
+int RegisterFromFunction() {
+  std::pair<const char*, const char*> cases[] = {
+      {"test1", "One"},
+      {"test2", "Two"},
+      {"test3", "Three"}
+  };
+  for (auto& c : cases)
+    benchmark::RegisterBenchmark(c.first, &BM_extra_args, c.second);
+  return 0;
+}
+int dummy2 = RegisterFromFunction();
+ADD_CASES(
+  {"test1", "One"},
+  {"test2", "Two"},
+  {"test3", "Three"}
+);
+
+#endif // BENCHMARK_HAS_NO_VARIADIC_REGISTER_BENCHMARK
+
+//----------------------------------------------------------------------------//
+// Test RegisterBenchmark with different callable types
+//----------------------------------------------------------------------------//
+
+struct CustomFixture {
+  void operator()(benchmark::State& st) {
+    while (st.KeepRunning()) {}
+  }
+};
+
+void TestRegistrationAtRuntime() {
+  {
+    CustomFixture fx;
+    benchmark::RegisterBenchmark("custom_fixture", fx);
+    AddCases({"custom_fixture"});
+  }
+#ifndef BENCHMARK_HAS_NO_VARIADIC_REGISTER_BENCHMARK
+  {
+    int x = 42;
+    auto capturing_lam = [=](benchmark::State& st) {
+      while (st.KeepRunning()) {}
+      st.SetLabel(std::to_string(x));
+    };
+    benchmark::RegisterBenchmark("lambda_benchmark", capturing_lam);
+    AddCases({{"lambda_benchmark", "42"}});
+  }
+#endif
+}
+
+int main(int argc, char* argv[]) {
+  TestRegistrationAtRuntime();
+
+  benchmark::Initialize(&argc, argv);
+
+  TestReporter test_reporter;
+  benchmark::RunSpecifiedBenchmarks(&test_reporter);
+
+  typedef benchmark::BenchmarkReporter::Run Run;
+  auto EB = ExpectedResults.begin();
+
+  for (Run const& run : test_reporter.all_runs_) {
+    assert(EB != ExpectedResults.end());
+    EB->CheckRun(run);
+    ++EB;
+  }
+  assert(EB == ExpectedResults.end());
+
+  return 0;
+}