1 //===- llvm/Support/Chrono.h - Utilities for Timing Manipulation-*- C++ -*-===//
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 #ifndef LLVM_SUPPORT_CHRONO_H
10 #define LLVM_SUPPORT_CHRONO_H
11
12 #include "llvm/Support/Compiler.h"
13 #include "llvm/Support/FormatProviders.h"
14
15 #include <chrono>
16 #include <ctime>
17
18 namespace llvm {
19
20 class raw_ostream;
21
22 namespace sys {
23
24 /// A time point on the system clock. This is provided for two reasons:
25 /// - to insulate us agains subtle differences in behavoir to differences in
26 /// system clock precision (which is implementation-defined and differs between
27 /// platforms).
28 /// - to shorten the type name
29 /// The default precision is nanoseconds. If need a specific precision specify
30 /// it explicitly. If unsure, use the default. If you need a time point on a
31 /// clock other than the system_clock, use std::chrono directly.
32 template <typename D = std::chrono::nanoseconds>
33 using TimePoint = std::chrono::time_point<std::chrono::system_clock, D>;
34
35 /// Convert a TimePoint to std::time_t
toTimeT(TimePoint<> TP)36 inline std::time_t toTimeT(TimePoint<> TP) {
37 using namespace std::chrono;
38 return system_clock::to_time_t(
39 time_point_cast<system_clock::time_point::duration>(TP));
40 }
41
42 /// Convert a std::time_t to a TimePoint
43 inline TimePoint<std::chrono::seconds>
toTimePoint(std::time_t T)44 toTimePoint(std::time_t T) {
45 using namespace std::chrono;
46 return time_point_cast<seconds>(system_clock::from_time_t(T));
47 }
48
49 /// Convert a std::time_t + nanoseconds to a TimePoint
50 inline TimePoint<>
toTimePoint(std::time_t T,uint32_t nsec)51 toTimePoint(std::time_t T, uint32_t nsec) {
52 using namespace std::chrono;
53 return time_point_cast<nanoseconds>(system_clock::from_time_t(T))
54 + nanoseconds(nsec);
55 }
56
57 } // namespace sys
58
59 raw_ostream &operator<<(raw_ostream &OS, sys::TimePoint<> TP);
60
61 /// Format provider for TimePoint<>
62 ///
63 /// The options string is a strftime format string, with extensions:
64 /// - %L is millis: 000-999
65 /// - %f is micros: 000000-999999
66 /// - %N is nanos: 000000000 - 999999999
67 ///
68 /// If no options are given, the default format is "%Y-%m-%d %H:%M:%S.%N".
69 template <>
70 struct format_provider<sys::TimePoint<>> {
71 static void format(const sys::TimePoint<> &TP, llvm::raw_ostream &OS,
72 StringRef Style);
73 };
74
75 namespace detail {
76 template <typename Period> struct unit { static const char value[]; };
77 template <typename Period> const char unit<Period>::value[] = "";
78
79 template <> struct unit<std::ratio<3600>> { static const char value[]; };
80 template <> struct unit<std::ratio<60>> { static const char value[]; };
81 template <> struct unit<std::ratio<1>> { static const char value[]; };
82 template <> struct unit<std::milli> { static const char value[]; };
83 template <> struct unit<std::micro> { static const char value[]; };
84 template <> struct unit<std::nano> { static const char value[]; };
85 } // namespace detail
86
87 /// Implementation of format_provider<T> for duration types.
88 ///
89 /// The options string of a duration type has the grammar:
90 ///
91 /// duration_options ::= [unit][show_unit [number_options]]
92 /// unit ::= `h`|`m`|`s`|`ms|`us`|`ns`
93 /// show_unit ::= `+` | `-`
94 /// number_options ::= options string for a integral or floating point type
95 ///
96 /// Examples
97 /// =================================
98 /// | options | Input | Output |
99 /// =================================
100 /// | "" | 1s | 1 s |
101 /// | "ms" | 1s | 1000 ms |
102 /// | "ms-" | 1s | 1000 |
103 /// | "ms-n" | 1s | 1,000 |
104 /// | "" | 1.0s | 1.00 s |
105 /// =================================
106 ///
107 /// If the unit of the duration type is not one of the units specified above,
108 /// it is still possible to format it, provided you explicitly request a
109 /// display unit or you request that the unit is not displayed.
110
111 template <typename Rep, typename Period>
112 struct format_provider<std::chrono::duration<Rep, Period>> {
113 private:
114 typedef std::chrono::duration<Rep, Period> Dur;
115 typedef std::conditional_t<std::chrono::treat_as_floating_point<Rep>::value,
116 double, intmax_t>
117 InternalRep;
118
119 template <typename AsPeriod> static InternalRep getAs(const Dur &D) {
120 using namespace std::chrono;
121 return duration_cast<duration<InternalRep, AsPeriod>>(D).count();
122 }
123
124 static std::pair<InternalRep, StringRef> consumeUnit(StringRef &Style,
125 const Dur &D) {
126 using namespace std::chrono;
127 if (Style.consume_front("ns"))
128 return {getAs<std::nano>(D), "ns"};
129 if (Style.consume_front("us"))
130 return {getAs<std::micro>(D), "us"};
131 if (Style.consume_front("ms"))
132 return {getAs<std::milli>(D), "ms"};
133 if (Style.consume_front("s"))
134 return {getAs<std::ratio<1>>(D), "s"};
135 if (Style.consume_front("m"))
136 return {getAs<std::ratio<60>>(D), "m"};
137 if (Style.consume_front("h"))
138 return {getAs<std::ratio<3600>>(D), "h"};
139 return {D.count(), detail::unit<Period>::value};
140 }
141
142 static bool consumeShowUnit(StringRef &Style) {
143 if (Style.empty())
144 return true;
145 if (Style.consume_front("-"))
146 return false;
147 if (Style.consume_front("+"))
148 return true;
149 assert(0 && "Unrecognised duration format");
150 return true;
151 }
152
153 public:
154 static void format(const Dur &D, llvm::raw_ostream &Stream, StringRef Style) {
155 InternalRep count;
156 StringRef unit;
157 std::tie(count, unit) = consumeUnit(Style, D);
158 bool show_unit = consumeShowUnit(Style);
159
160 format_provider<InternalRep>::format(count, Stream, Style);
161
162 if (show_unit) {
163 assert(!unit.empty());
164 Stream << " " << unit;
165 }
166 }
167 };
168
169 } // namespace llvm
170
171 #endif // LLVM_SUPPORT_CHRONO_H
172