Add ArgName() and ArgNames() methods to name arguments/ranges.

include/benchmark/benchmark_api.h

@@ -510,6 +510,13 @@ class Benchmark {
   // REQUIRES: The function passed to the constructor must accept arg1, arg2 ...
   Benchmark* Ranges(const std::vector<std::pair<int, int> >& ranges);
 
+  // Equivalent to ArgNames({name})
+  Benchmark* ArgName(const std::string& name);
+
+  // Set the argument names to display in the benchmark name. If not called,
+  // only argument values will be shown.
+  Benchmark* ArgNames(const std::vector<std::string>& names);
+
   // Equivalent to Ranges({{lo1, hi1}, {lo2, hi2}}).
   // NOTE: This is a legacy C++03 interface provided for compatibility only.
   //   New code should use 'Ranges'.
@@ -526,8 +533,7 @@ class Benchmark {
   Benchmark* Apply(void (*func)(Benchmark* benchmark));
 
   // Set the range multiplier for non-dense range. If not called, the range
-  // multiplier
-  // kRangeMultiplier will be used.
+  // multiplier kRangeMultiplier will be used.
   Benchmark* RangeMultiplier(int multiplier);
 
   // Set the minimum amount of time to use when running this benchmark. This
@@ -618,6 +624,7 @@ class Benchmark {
 
   std::string name_;
   ReportMode report_mode_;
+  std::vector<std::string> arg_names_;   // Args for all benchmark runs
   std::vector<std::vector<int> > args_;  // Args for all benchmark runs
   TimeUnit time_unit_;
   int range_multiplier_;

src/benchmark_register.cc

@@ -151,8 +151,16 @@ bool BenchmarkFamilies::FindBenchmarks(
         instance.threads = num_threads;
 
         // Add arguments to instance name
+        size_t arg_i = 0;
         for (auto const& arg : args) {
+          if (arg_i < family->arg_names_.size()) {
+            instance.name +=
+                StringPrintF("/%s:", family->arg_names_[arg_i].c_str());
+          } else {
+            instance.name += "/";
+          }
           AppendHumanReadable(arg, &instance.name);
+          ++arg_i;
         }
 
         if (!IsZero(family->min_time_)) {
@@ -293,6 +301,16 @@ Benchmark* Benchmark::Ranges(const std::vector<std::pair<int, int>>& ranges) {
   return this;
 }
 
+Benchmark* Benchmark::ArgName(const std::string& name) {
+  arg_names_ = {name};
+  return this;
+}
+
+Benchmark* Benchmark::ArgNames(const std::vector<std::string>& names) {
+  arg_names_ = names;
+  return this;
+}
+
 Benchmark* Benchmark::DenseRange(int start, int limit, int step) {
   CHECK(ArgsCnt() == -1 || ArgsCnt() == 1);
   CHECK_GE(start, 0);

src/string_util.cc

@@ -107,7 +107,7 @@ std::string ToBinaryStringFullySpecified(double value, double threshold,
 void AppendHumanReadable(int n, std::string* str) {
   std::stringstream ss;
   // Round down to the nearest SI prefix.
-  ss << "/" << ToBinaryStringFullySpecified(n, 1.0, 0);
+  ss << ToBinaryStringFullySpecified(n, 1.0, 0);
   *str += ss.str();
 }
 

test/reporter_output_test.cc

@@ -52,6 +52,46 @@ ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_error\",$"},
 ADD_CASES(TC_CSVOut, {{"^\"BM_error\",,,,,,,,true,\"message\"$"}});
 
 // ========================================================================= //
+// ------------------------ Testing No Arg Name Output -----------------------
+// //
+// ========================================================================= //
+
+void BM_no_arg_name(benchmark::State& state) {
+  while (state.KeepRunning()) {
+  }
+}
+BENCHMARK(BM_no_arg_name)->Arg(3);
+ADD_CASES(TC_ConsoleOut, {{"^BM_no_arg_name/3 %console_report$"}});
+ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_no_arg_name/3\",$"}});
+ADD_CASES(TC_CSVOut, {{"^\"BM_no_arg_name/3\",%csv_report$"}});
+
+// ========================================================================= //
+// ------------------------ Testing Arg Name Output ----------------------- //
+// ========================================================================= //
+
+void BM_arg_name(benchmark::State& state) {
+  while (state.KeepRunning()) {
+  }
+}
+BENCHMARK(BM_arg_name)->Arg(3)->ArgName("first");
+ADD_CASES(TC_ConsoleOut, {{"^BM_arg_name/first:3 %console_report$"}});
+ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_arg_name/first:3\",$"}});
+ADD_CASES(TC_CSVOut, {{"^\"BM_arg_name/first:3\",%csv_report$"}});
+
+// ========================================================================= //
+// ------------------------ Testing Arg Names Output ----------------------- //
+// ========================================================================= //
+
+void BM_arg_names(benchmark::State& state) {
+  while (state.KeepRunning()) {
+  }
+}
+BENCHMARK(BM_arg_names)->Args({2, 4})->ArgNames({"first", "second"});
+ADD_CASES(TC_ConsoleOut, {{"^BM_arg_names/first:2/second:4 %console_report$"}});
+ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_arg_names/first:2/second:4\",$"}});
+ADD_CASES(TC_CSVOut, {{"^\"BM_arg_names/first:2/second:4\",%csv_report$"}});
+
+// ========================================================================= //
 // ----------------------- Testing Complexity Output ----------------------- //
 // ========================================================================= //