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 31 namespace llvm { 32 class raw_ostream; 33 34 class Statistic { 35 public: 36 const char *Name; 37 const char *Desc; 38 volatile llvm::sys::cas_flag Value; 39 bool Initialized; 40 41 llvm::sys::cas_flag getValue() const { return Value; } 42 const char *getName() const { return Name; } 43 const char *getDesc() const { return Desc; } 44 45 /// construct - This should only be called for non-global statistics. 46 void construct(const char *name, const char *desc) { 47 Name = name; Desc = desc; 48 Value = 0; Initialized = 0; 49 } 50 51 // Allow use of this class as the value itself. 52 operator unsigned() const { return Value; } 53 const Statistic &operator=(unsigned Val) { 54 Value = Val; 55 return init(); 56 } 57 58 const Statistic &operator++() { 59 // FIXME: This function and all those that follow carefully use an 60 // atomic operation to update the value safely in the presence of 61 // concurrent accesses, but not to read the return value, so the 62 // return value is not thread safe. 63 sys::AtomicIncrement(&Value); 64 return init(); 65 } 66 67 unsigned operator++(int) { 68 init(); 69 unsigned OldValue = Value; 70 sys::AtomicIncrement(&Value); 71 return OldValue; 72 } 73 74 const Statistic &operator--() { 75 sys::AtomicDecrement(&Value); 76 return init(); 77 } 78 79 unsigned operator--(int) { 80 init(); 81 unsigned OldValue = Value; 82 sys::AtomicDecrement(&Value); 83 return OldValue; 84 } 85 86 const Statistic &operator+=(const unsigned &V) { 87 if (!V) return *this; 88 sys::AtomicAdd(&Value, V); 89 return init(); 90 } 91 92 const Statistic &operator-=(const unsigned &V) { 93 if (!V) return *this; 94 sys::AtomicAdd(&Value, -V); 95 return init(); 96 } 97 98 const Statistic &operator*=(const unsigned &V) { 99 sys::AtomicMul(&Value, V); 100 return init(); 101 } 102 103 const Statistic &operator/=(const unsigned &V) { 104 sys::AtomicDiv(&Value, V); 105 return init(); 106 } 107 108 protected: 109 Statistic &init() { 110 bool tmp = Initialized; 111 sys::MemoryFence(); 112 if (!tmp) RegisterStatistic(); 113 return *this; 114 } 115 void RegisterStatistic(); 116 }; 117 118 // STATISTIC - A macro to make definition of statistics really simple. This 119 // automatically passes the DEBUG_TYPE of the file into the statistic. 120 #define STATISTIC(VARNAME, DESC) \ 121 static llvm::Statistic VARNAME = { DEBUG_TYPE, DESC, 0, 0 } 122 123 /// \brief Enable the collection and printing of statistics. 124 void EnableStatistics(); 125 126 /// \brief Check if statistics are enabled. 127 bool AreStatisticsEnabled(); 128 129 /// \brief Print statistics to the file returned by CreateInfoOutputFile(). 130 void PrintStatistics(); 131 132 /// \brief Print statistics to the given output stream. 133 void PrintStatistics(raw_ostream &OS); 134 135 } // End llvm namespace 136 137 #endif 138
