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/Valgrind.h" 31 32 namespace llvm { 33 class raw_ostream; 34 35 class Statistic { 36 public: 37 const char *Name; 38 const char *Desc; 39 volatile llvm::sys::cas_flag Value; 40 bool Initialized; 41 getValue()42 llvm::sys::cas_flag getValue() const { return Value; } getName()43 const char *getName() const { return Name; } getDesc()44 const char *getDesc() const { return Desc; } 45 46 /// construct - This should only be called for non-global statistics. construct(const char * name,const char * desc)47 void construct(const char *name, const char *desc) { 48 Name = name; Desc = desc; 49 Value = 0; Initialized = 0; 50 } 51 52 // Allow use of this class as the value itself. 53 operator unsigned() const { return Value; } 54 const Statistic &operator=(unsigned Val) { 55 Value = Val; 56 return init(); 57 } 58 59 const Statistic &operator++() { 60 // FIXME: This function and all those that follow carefully use an 61 // atomic operation to update the value safely in the presence of 62 // concurrent accesses, but not to read the return value, so the 63 // return value is not thread safe. 64 sys::AtomicIncrement(&Value); 65 return init(); 66 } 67 68 unsigned operator++(int) { 69 init(); 70 unsigned OldValue = Value; 71 sys::AtomicIncrement(&Value); 72 return OldValue; 73 } 74 75 const Statistic &operator--() { 76 sys::AtomicDecrement(&Value); 77 return init(); 78 } 79 80 unsigned operator--(int) { 81 init(); 82 unsigned OldValue = Value; 83 sys::AtomicDecrement(&Value); 84 return OldValue; 85 } 86 87 const Statistic &operator+=(const unsigned &V) { 88 if (!V) return *this; 89 sys::AtomicAdd(&Value, V); 90 return init(); 91 } 92 93 const Statistic &operator-=(const unsigned &V) { 94 if (!V) return *this; 95 sys::AtomicAdd(&Value, -V); 96 return init(); 97 } 98 99 const Statistic &operator*=(const unsigned &V) { 100 sys::AtomicMul(&Value, V); 101 return init(); 102 } 103 104 const Statistic &operator/=(const unsigned &V) { 105 sys::AtomicDiv(&Value, V); 106 return init(); 107 } 108 109 protected: init()110 Statistic &init() { 111 bool tmp = Initialized; 112 sys::MemoryFence(); 113 if (!tmp) RegisterStatistic(); 114 TsanHappensAfter(this); 115 return *this; 116 } 117 void RegisterStatistic(); 118 }; 119 120 // STATISTIC - A macro to make definition of statistics really simple. This 121 // automatically passes the DEBUG_TYPE of the file into the statistic. 122 #define STATISTIC(VARNAME, DESC) \ 123 static llvm::Statistic VARNAME = { DEBUG_TYPE, DESC, 0, 0 } 124 125 /// \brief Enable the collection and printing of statistics. 126 void EnableStatistics(); 127 128 /// \brief Check if statistics are enabled. 129 bool AreStatisticsEnabled(); 130 131 /// \brief Print statistics to the file returned by CreateInfoOutputFile(). 132 void PrintStatistics(); 133 134 /// \brief Print statistics to the given output stream. 135 void PrintStatistics(raw_ostream &OS); 136 137 } // End llvm namespace 138 139 #endif 140