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
17 namespace internal {
18
19 template <class D, class E, size_t I>
20 struct EnumValue : std::integral_constant<E, static_cast<E>(I)> {
nameEnumValue21 static std::string name() { return std::string("_") + D::Names[I]; }
22 };
23
24 template <class D, class E, size_t... Idxs>
makeEnumValueTuple(std::index_sequence<Idxs...>)25 constexpr auto makeEnumValueTuple(std::index_sequence<Idxs...>) {
26 return std::make_tuple(EnumValue<D, E, Idxs>{}...);
27 }
28
29 template <class B>
30 static auto skip(const B& Bench, int) -> decltype(Bench.skip()) {
31 return Bench.skip();
32 }
33 template <class B>
skip(const B & Bench,char)34 static auto skip(const B& Bench, char) {
35 return false;
36 }
37
38 template <class B, class Args, size_t... Is>
makeBenchmarkFromValuesImpl(const Args & A,std::index_sequence<Is...>)39 void 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
48 template <class B, class... Args>
makeBenchmarkFromValues(const std::vector<std::tuple<Args...>> & A)49 void makeBenchmarkFromValues(const std::vector<std::tuple<Args...> >& A) {
50 makeBenchmarkFromValuesImpl<B>(A, std::index_sequence_for<Args...>());
51 }
52
53 template <template <class...> class B, class Args, class... U>
makeBenchmarkImpl(const Args & A,std::tuple<U...> t)54 void makeBenchmarkImpl(const Args& A, std::tuple<U...> t) {
55 makeBenchmarkFromValues<B<U...> >(A);
56 }
57
58 template <template <class...> class B, class Args, class... U, class... T, class... Tuples>
makeBenchmarkImpl(const Args & A,std::tuple<U...>,std::tuple<T...>,Tuples...rest)59 void makeBenchmarkImpl(const Args& A, std::tuple<U...>, std::tuple<T...>, Tuples... rest) {
60 (internal::makeBenchmarkImpl<B>(A, std::tuple<U..., T>(), rest...), ...);
61 }
62
63 template <class R, class T>
allValueCombinations(R & Result,const T & Final)64 void allValueCombinations(R& Result, const T& Final) {
65 return Result.push_back(Final);
66 }
67
68 template <class R, class T, class V, class... Vs>
allValueCombinations(R & Result,const T & Prev,const V & Value,const Vs &...Values)69 void 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 // };
88 template <class Derived, class EnumType, size_t NumLabels>
89 using 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.
103 template <template <class...> class B, class... Tuples, class... Args>
makeCartesianProductBenchmark(const Args &...A)104 int 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
111 template <class B, class... Args>
makeCartesianProductBenchmark(const Args &...A)112 int 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`.
122 template <class T>
maybeOpaque(T value,bool opaque)123 TEST_ALWAYS_INLINE inline T maybeOpaque(T value, bool opaque) {
124 if (opaque)
125 benchmark::DoNotOptimize(value);
126 return value;
127 }
128