1 //===- llvm/Support/Chrono.h - Utilities for Timing Manipulation-*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef LLVM_SUPPORT_CHRONO_H 11 #define LLVM_SUPPORT_CHRONO_H 12 13 #include "llvm/Support/Compiler.h" 14 #include "llvm/Support/FormatProviders.h" 15 16 #include <chrono> 17 #include <ctime> 18 19 namespace llvm { 20 21 class raw_ostream; 22 23 namespace sys { 24 25 /// A time point on the system clock. This is provided for two reasons: 26 /// - to insulate us agains subtle differences in behavoir to differences in 27 /// system clock precision (which is implementation-defined and differs between 28 /// platforms). 29 /// - to shorten the type name 30 /// The default precision is nanoseconds. If need a specific precision specify 31 /// it explicitly. If unsure, use the default. If you need a time point on a 32 /// clock other than the system_clock, use std::chrono directly. 33 template <typename D = std::chrono::nanoseconds> 34 using TimePoint = std::chrono::time_point<std::chrono::system_clock, D>; 35 36 /// Convert a TimePoint to std::time_t 37 LLVM_ATTRIBUTE_ALWAYS_INLINE inline std::time_t toTimeT(TimePoint<> TP) { 38 using namespace std::chrono; 39 return system_clock::to_time_t( 40 time_point_cast<system_clock::time_point::duration>(TP)); 41 } 42 43 /// Convert a std::time_t to a TimePoint 44 LLVM_ATTRIBUTE_ALWAYS_INLINE inline TimePoint<std::chrono::seconds> 45 toTimePoint(std::time_t T) { 46 using namespace std::chrono; 47 return time_point_cast<seconds>(system_clock::from_time_t(T)); 48 } 49 50 } // namespace sys 51 52 raw_ostream &operator<<(raw_ostream &OS, sys::TimePoint<> TP); 53 54 /// Implementation of format_provider<T> for duration types. 55 /// 56 /// The options string of a duration type has the grammar: 57 /// 58 /// duration_options ::= [unit][show_unit [number_options]] 59 /// unit ::= `h`|`m`|`s`|`ms|`us`|`ns` 60 /// show_unit ::= `+` | `-` 61 /// number_options ::= options string for a integral or floating point type 62 /// 63 /// Examples 64 /// ================================= 65 /// | options | Input | Output | 66 /// ================================= 67 /// | "" | 1s | 1 s | 68 /// | "ms" | 1s | 1000 ms | 69 /// | "ms-" | 1s | 1000 | 70 /// | "ms-n" | 1s | 1,000 | 71 /// | "" | 1.0s | 1.00 s | 72 /// ================================= 73 /// 74 /// If the unit of the duration type is not one of the units specified above, 75 /// it is still possible to format it, provided you explicitly request a 76 /// display unit or you request that the unit is not displayed. 77 78 namespace detail { 79 template <typename Period> struct unit { static const char value[]; }; 80 template <typename Period> const char unit<Period>::value[] = ""; 81 82 template <> struct unit<std::ratio<3600>> { static const char value[]; }; 83 template <> struct unit<std::ratio<60>> { static const char value[]; }; 84 template <> struct unit<std::ratio<1>> { static const char value[]; }; 85 template <> struct unit<std::milli> { static const char value[]; }; 86 template <> struct unit<std::micro> { static const char value[]; }; 87 template <> struct unit<std::nano> { static const char value[]; }; 88 } // namespace detail 89 90 template <typename Rep, typename Period> 91 struct format_provider<std::chrono::duration<Rep, Period>> { 92 private: 93 typedef std::chrono::duration<Rep, Period> Dur; 94 typedef typename std::conditional< 95 std::chrono::treat_as_floating_point<Rep>::value, double, intmax_t>::type 96 InternalRep; 97 98 template <typename AsPeriod> static InternalRep getAs(const Dur &D) { 99 using namespace std::chrono; 100 return duration_cast<duration<InternalRep, AsPeriod>>(D).count(); 101 } 102 103 static std::pair<InternalRep, StringRef> consumeUnit(StringRef &Style, 104 const Dur &D) { 105 using namespace std::chrono; 106 if (Style.consume_front("ns")) 107 return {getAs<std::nano>(D), "ns"}; 108 if (Style.consume_front("us")) 109 return {getAs<std::micro>(D), "us"}; 110 if (Style.consume_front("ms")) 111 return {getAs<std::milli>(D), "ms"}; 112 if (Style.consume_front("s")) 113 return {getAs<std::ratio<1>>(D), "s"}; 114 if (Style.consume_front("m")) 115 return {getAs<std::ratio<60>>(D), "m"}; 116 if (Style.consume_front("h")) 117 return {getAs<std::ratio<3600>>(D), "h"}; 118 return {D.count(), detail::unit<Period>::value}; 119 } 120 121 static bool consumeShowUnit(StringRef &Style) { 122 if (Style.empty()) 123 return true; 124 if (Style.consume_front("-")) 125 return false; 126 if (Style.consume_front("+")) 127 return true; 128 assert(0 && "Unrecognised duration format"); 129 return true; 130 } 131 132 public: 133 static void format(const Dur &D, llvm::raw_ostream &Stream, StringRef Style) { 134 InternalRep count; 135 StringRef unit; 136 std::tie(count, unit) = consumeUnit(Style, D); 137 bool show_unit = consumeShowUnit(Style); 138 139 format_provider<InternalRep>::format(count, Stream, Style); 140 141 if (show_unit) { 142 assert(!unit.empty()); 143 Stream << " " << unit; 144 } 145 } 146 }; 147 148 } // namespace llvm 149 150 #endif // LLVM_SUPPORT_CHRONO_H 151
