Statistic.h revision 1f6efa3996dd1929fbc129203ce5009b620e6969
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 31namespace llvm { 32class raw_ostream; 33 34class Statistic { 35public: 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 sys::AtomicAdd(&Value, V); 88 return init(); 89 } 90 91 const Statistic &operator-=(const unsigned &V) { 92 sys::AtomicAdd(&Value, -V); 93 return init(); 94 } 95 96 const Statistic &operator*=(const unsigned &V) { 97 sys::AtomicMul(&Value, V); 98 return init(); 99 } 100 101 const Statistic &operator/=(const unsigned &V) { 102 sys::AtomicDiv(&Value, V); 103 return init(); 104 } 105 106protected: 107 Statistic &init() { 108 bool tmp = Initialized; 109 sys::MemoryFence(); 110 if (!tmp) RegisterStatistic(); 111 return *this; 112 } 113 void RegisterStatistic(); 114}; 115 116// STATISTIC - A macro to make definition of statistics really simple. This 117// automatically passes the DEBUG_TYPE of the file into the statistic. 118#define STATISTIC(VARNAME, DESC) \ 119 static llvm::Statistic VARNAME = { DEBUG_TYPE, DESC, 0, 0 } 120 121/// \brief Enable the collection and printing of statistics. 122void EnableStatistics(); 123 124/// \brief Print statistics to the file returned by CreateInfoOutputFile(). 125void PrintStatistics(); 126 127/// \brief Print statistics to the given output stream. 128void PrintStatistics(raw_ostream &OS); 129 130} // End llvm namespace 131 132#endif 133