Implement custom benchmark name (#1107)

* Implement custom benchmark name

The benchmark's name can be changed using the Name() function
which internally uses SetName().

* Update AUTHORS and CONTRIBUTORS

* Describe new feature in README

* Move new name function up

Fixes #1106

AUTHORS

@@ -52,6 +52,7 @@ Sayan Bhattacharjee <aero.sayan@gmail.com>
 Shuo Chen <chenshuo@chenshuo.com>
 Steinar H. Gunderson <sgunderson@bigfoot.com>
 Stripe, Inc.
+Tobias Schmidt <tobias.schmidt@in.tum.de>
 Yixuan Qiu <yixuanq@gmail.com>
 Yusuke Suzuki <utatane.tea@gmail.com>
 Zbigniew Skowron <zbychs@gmail.com>

CONTRIBUTORS

@@ -75,6 +75,7 @@ Roman Lebedev <lebedev.ri@gmail.com>
 Sayan Bhattacharjee <aero.sayan@gmail.com>
 Shuo Chen <chenshuo@chenshuo.com>
 Steven Wan <wan.yu@ibm.com>
+Tobias Schmidt <tobias.schmidt@in.tum.de>
 Tobias Ulvgård <tobias.ulvgard@dirac.se>
 Tom Madams <tom.ej.madams@gmail.com> <tmadams@google.com>
 Yixuan Qiu <yixuanq@gmail.com>

README.md

@@ -278,6 +278,8 @@ too (`-lkstat`).
 
 [Passing Arguments](#passing-arguments)
 
+[Custom Benchmark Name](#custom-benchmark-name)
+
 [Calculating Asymptotic Complexity](#asymptotic-complexity)
 
 [Templated Benchmarks](#templated-benchmarks)
@@ -652,6 +654,19 @@ BENCHMARK(BM_StringCompare)->RangeMultiplier(2)
     ->Range(1<<10, 1<<18)->Complexity([](benchmark::IterationCount n)->double{return n; });
 ```
 
+<a name="custom-benchmark-name" />
+
+### Custom Benchmark Name
+
+You can change the benchmark's name as follows:
+
+```c++
+BENCHMARK(BM_memcpy)->Name("memcpy")->RangeMultiplier(2)->Range(8, 8<<10);
+```
+
+The invocation will execute the benchmark as before using `BM_memcpy` but changes
+the prefix in the report to `memcpy`.
+
 <a name="templated-benchmarks" />
 
 ### Templated Benchmarks

include/benchmark/benchmark.h

@@ -790,6 +790,9 @@ class Benchmark {
   // Note: the following methods all return "this" so that multiple
   // method calls can be chained together in one expression.
 
+  // Specify the name of the benchmark
+  Benchmark* Name(const std::string& name);
+
   // Run this benchmark once with "x" as the extra argument passed
   // to the function.
   // REQUIRES: The function passed to the constructor must accept an arg1.

src/benchmark_register.cc

@@ -278,6 +278,11 @@ Benchmark::Benchmark(const char* name)
 
 Benchmark::~Benchmark() {}
 
+Benchmark* Benchmark::Name(const std::string& name) {
+  SetName(name.c_str());
+  return this;
+}
+
 Benchmark* Benchmark::Arg(int64_t x) {
   CHECK(ArgsCnt() == -1 || ArgsCnt() == 1);
   args_.push_back({x});

test/reporter_output_test.cc

@@ -334,6 +334,30 @@ ADD_CASES(TC_JSONOut,
            {"\"threads\": 1,$", MR_Next}});
 ADD_CASES(TC_CSVOut, {{"^\"BM_arg_names/first:2/5/third:4\",%csv_report$"}});
 
+// ========================================================================= //
+// ------------------------ Testing Name Output ---------------------------- //
+// ========================================================================= //
+
+void BM_name(benchmark::State& state) {
+  for (auto _ : state) {
+  }
+}
+BENCHMARK(BM_name)->Name("BM_custom_name");
+
+ADD_CASES(TC_ConsoleOut, {{"^BM_custom_name %console_report$"}});
+ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_custom_name\",$"},
+                       {"\"run_name\": \"BM_custom_name\",$", MR_Next},
+                       {"\"run_type\": \"iteration\",$", MR_Next},
+                       {"\"repetitions\": 0,$", MR_Next},
+                       {"\"repetition_index\": 0,$", MR_Next},
+                       {"\"threads\": 1,$", MR_Next},
+                       {"\"iterations\": %int,$", MR_Next},
+                       {"\"real_time\": %float,$", MR_Next},
+                       {"\"cpu_time\": %float,$", MR_Next},
+                       {"\"time_unit\": \"ns\"$", MR_Next},
+                       {"}", MR_Next}});
+ADD_CASES(TC_CSVOut, {{"^\"BM_custom_name\",%csv_report$"}});
+
 // ========================================================================= //
 // ------------------------ Testing Big Args Output ------------------------ //
 // ========================================================================= //