1 //===-- llvm/ADT/Statistic.h - Easy way to expose stats ---------*- 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 // This file defines the 'Statistic' class, which is designed to be an easy way 11 // to expose various metrics from passes. These statistics are printed at the 12 // end of a run (from llvm_shutdown), when the -stats command line option is 13 // passed on the command line. 14 // 15 // This is useful for reporting information like the number of instructions 16 // simplified, optimized or removed by various transformations, like this: 17 // 18 // static Statistic NumInstsKilled("gcse", "Number of instructions killed"); 19 // 20 // Later, in the code: ++NumInstsKilled; 21 // 22 // NOTE: Statistics *must* be declared as global variables. 23 // 24 //===----------------------------------------------------------------------===// 25 26 #ifndef LLVM_ADT_STATISTIC_H 27 #define LLVM_ADT_STATISTIC_H 28 29 #include "llvm/Support/Atomic.h" 30 #include "llvm/Support/Compiler.h" 31 #include <atomic> 32 #include <memory> 33 34 namespace llvm { 35 36 class raw_ostream; 37 class raw_fd_ostream; 38 39 class Statistic { 40 public: 41 const char *DebugType; 42 const char *Name; 43 const char *Desc; 44 std::atomic<unsigned> Value; 45 bool Initialized; 46 47 unsigned getValue() const { return Value.load(std::memory_order_relaxed); } 48 const char *getDebugType() const { return DebugType; } 49 const char *getName() const { return Name; } 50 const char *getDesc() const { return Desc; } 51 52 /// construct - This should only be called for non-global statistics. 53 void construct(const char *debugtype, const char *name, const char *desc) { 54 DebugType = debugtype; 55 Name = name; 56 Desc = desc; 57 Value = 0; 58 Initialized = false; 59 } 60 61 // Allow use of this class as the value itself. 62 operator unsigned() const { return getValue(); } 63 64 #if !defined(NDEBUG) || defined(LLVM_ENABLE_STATS) 65 const Statistic &operator=(unsigned Val) { 66 Value.store(Val, std::memory_order_relaxed); 67 return init(); 68 } 69 70 const Statistic &operator++() { 71 Value.fetch_add(1, std::memory_order_relaxed); 72 return init(); 73 } 74 75 unsigned operator++(int) { 76 init(); 77 return Value.fetch_add(1, std::memory_order_relaxed); 78 } 79 80 const Statistic &operator--() { 81 Value.fetch_sub(1, std::memory_order_relaxed); 82 return init(); 83 } 84 85 unsigned operator--(int) { 86 init(); 87 return Value.fetch_sub(1, std::memory_order_relaxed); 88 } 89 90 const Statistic &operator+=(unsigned V) { 91 if (V == 0) 92 return *this; 93 Value.fetch_add(V, std::memory_order_relaxed); 94 return init(); 95 } 96 97 const Statistic &operator-=(unsigned V) { 98 if (V == 0) 99 return *this; 100 Value.fetch_sub(V, std::memory_order_relaxed); 101 return init(); 102 } 103 104 void updateMax(unsigned V) { 105 unsigned PrevMax = Value.load(std::memory_order_relaxed); 106 // Keep trying to update max until we succeed or another thread produces 107 // a bigger max than us. 108 while (V > PrevMax && !Value.compare_exchange_weak( 109 PrevMax, V, std::memory_order_relaxed)) { 110 } 111 init(); 112 } 113 114 #else // Statistics are disabled in release builds. 115 116 const Statistic &operator=(unsigned Val) { 117 return *this; 118 } 119 120 const Statistic &operator++() { 121 return *this; 122 } 123 124 unsigned operator++(int) { 125 return 0; 126 } 127 128 const Statistic &operator--() { 129 return *this; 130 } 131 132 unsigned operator--(int) { 133 return 0; 134 } 135 136 const Statistic &operator+=(const unsigned &V) { 137 return *this; 138 } 139 140 const Statistic &operator-=(const unsigned &V) { 141 return *this; 142 } 143 144 void updateMax(unsigned V) {} 145 146 #endif // !defined(NDEBUG) || defined(LLVM_ENABLE_STATS) 147 148 protected: 149 Statistic &init() { 150 bool tmp = Initialized; 151 sys::MemoryFence(); 152 if (!tmp) RegisterStatistic(); 153 TsanHappensAfter(this); 154 return *this; 155 } 156 157 void RegisterStatistic(); 158 }; 159 160 // STATISTIC - A macro to make definition of statistics really simple. This 161 // automatically passes the DEBUG_TYPE of the file into the statistic. 162 #define STATISTIC(VARNAME, DESC) \ 163 static llvm::Statistic VARNAME = {DEBUG_TYPE, #VARNAME, DESC, {0}, false} 164 165 /// \brief Enable the collection and printing of statistics. 166 void EnableStatistics(bool PrintOnExit = true); 167 168 /// \brief Check if statistics are enabled. 169 bool AreStatisticsEnabled(); 170 171 /// \brief Return a file stream to print our output on. 172 std::unique_ptr<raw_fd_ostream> CreateInfoOutputFile(); 173 174 /// \brief Print statistics to the file returned by CreateInfoOutputFile(). 175 void PrintStatistics(); 176 177 /// \brief Print statistics to the given output stream. 178 void PrintStatistics(raw_ostream &OS); 179 180 /// Print statistics in JSON format. This does include all global timers (\see 181 /// Timer, TimerGroup). Note that the timers are cleared after printing and will 182 /// not be printed in human readable form or in a second call of 183 /// PrintStatisticsJSON(). 184 void PrintStatisticsJSON(raw_ostream &OS); 185 186 } // end namespace llvm 187 188 #endif // LLVM_ADT_STATISTIC_H 189
