1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include <string>
10#include <tuple>
11#include <type_traits>
12#include <vector>
13
14#include "benchmark/benchmark.h"
15#include "test_macros.h"
16
17namespace internal {
18
19template <class D, class E, size_t I>
20struct EnumValue : std::integral_constant<E, static_cast<E>(I)> {
21 static std::string name() { return std::string("_") + D::Names[I]; }
22};
23
24template <class D, class E, size_t... Idxs>
25constexpr auto makeEnumValueTuple(std::index_sequence<Idxs...>) {
26 return std::make_tuple(EnumValue<D, E, Idxs>{}...);
27}
28
29template <class B>
30auto skip(const B& Bench, int) -> decltype(Bench.skip()) {
31 return Bench.skip();
32}
33template <class B>
34auto skip(const B&, char) {
35 return false;
36}
37
38template <class B, class Args, size_t... Is>
39void makeBenchmarkFromValuesImpl(const Args& A, std::index_sequence<Is...>) {
40 for (auto& V : A) {
41 B Bench{std::get<Is>(V)...};
42 if (!internal::skip(Bench, 0)) {
43 benchmark::RegisterBenchmark(Bench.name().c_str(), [=](benchmark::State& S) { Bench.run(S); });
44 }
45 }
46}
47
48template <class B, class... Args>
49void makeBenchmarkFromValues(const std::vector<std::tuple<Args...> >& A) {
50 makeBenchmarkFromValuesImpl<B>(A, std::index_sequence_for<Args...>());
51}
52
53template <template <class...> class B, class Args, class... U>
54void makeBenchmarkImpl(const Args& A, std::tuple<U...>) {
55 makeBenchmarkFromValues<B<U...> >(A);
56}
57
58template <template <class...> class B, class Args, class... U, class... T, class... Tuples>
59void makeBenchmarkImpl(const Args& A, std::tuple<U...>, std::tuple<T...>, Tuples... rest) {
60 (internal::makeBenchmarkImpl<B>(A, std::tuple<U..., T>(), rest...), ...);
61}
62
63template <class R, class T>
64void allValueCombinations(R& Result, const T& Final) {
65 return Result.push_back(Final);
66}
67
68template <class R, class T, class V, class... Vs>
69void allValueCombinations(R& Result, const T& Prev, const V& Value, const Vs&... Values) {
70 for (const auto& E : Value) {
71 allValueCombinations(Result, std::tuple_cat(Prev, std::make_tuple(E)), Values...);
72 }
73}
74
75} // namespace internal
76
77// CRTP class that enables using enum types as a dimension for
78// makeCartesianProductBenchmark below.
79// The type passed to `B` will be a std::integral_constant<E, e>, with the
80// additional static function `name()` that returns the stringified name of the
81// label.
82//
83// Eg:
84// enum class MyEnum { A, B };
85// struct AllMyEnum : EnumValuesAsTuple<AllMyEnum, MyEnum, 2> {
86// static constexpr absl::string_view Names[] = {"A", "B"};
87// };
88template <class Derived, class EnumType, size_t NumLabels>
89using EnumValuesAsTuple =
90 decltype(internal::makeEnumValueTuple<Derived, EnumType>(std::make_index_sequence<NumLabels>{}));
91
92// Instantiates B<T0, T1, ..., TN> where <Ti...> are the combinations in the
93// cartesian product of `Tuples...`, and pass (arg0, ..., argN) as constructor
94// arguments where `(argi...)` are the combination in the cartesian product of
95// the runtime values of `A...`.
96// B<T...> requires:
97// - std::string name(args...): The name of the benchmark.
98// - void run(benchmark::State&, args...): The body of the benchmark.
99// It can also optionally provide:
100// - bool skip(args...): When `true`, skips the combination. Default is false.
101//
102// Returns int to facilitate registration. The return value is unspecified.
103template <template <class...> class B, class... Tuples, class... Args>
104int makeCartesianProductBenchmark(const Args&... A) {
105 std::vector<std::tuple<typename Args::value_type...> > V;
106 internal::allValueCombinations(V, std::tuple<>(), A...);
107 internal::makeBenchmarkImpl<B>(V, std::tuple<>(), Tuples()...);
108 return 0;
109}
110
111template <class B, class... Args>
112int makeCartesianProductBenchmark(const Args&... A) {
113 std::vector<std::tuple<typename Args::value_type...> > V;
114 internal::allValueCombinations(V, std::tuple<>(), A...);
115 internal::makeBenchmarkFromValues<B>(V);
116 return 0;
117}
118
119// When `opaque` is true, this function hides the runtime state of `value` from
120// the optimizer.
121// It returns `value`.
122template <class T>
123TEST_ALWAYS_INLINE inline T maybeOpaque(T value, bool opaque) {
124 if (opaque)
125 benchmark::DoNotOptimize(value);
126 return value;
127}
128

source code of libcxx/test/benchmarks/CartesianBenchmarks.h