1//===-- Statistic.cpp - Easy way to expose stats information --------------===// 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 implements the 'Statistic' class, which is designed to be an easy 11// way to expose various success metrics from passes. These statistics are 12// printed at the end of a run, when the -stats command line option is enabled 13// 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 NumInstEliminated("GCSE", "Number of instructions killed"); 19// 20// Later, in the code: ++NumInstEliminated; 21// 22//===----------------------------------------------------------------------===// 23 24#include "llvm/ADT/Statistic.h" 25#include "llvm/Support/CommandLine.h" 26#include "llvm/Support/Debug.h" 27#include "llvm/Support/Format.h" 28#include "llvm/Support/ManagedStatic.h" 29#include "llvm/Support/raw_ostream.h" 30#include "llvm/Support/Mutex.h" 31#include "llvm/ADT/StringExtras.h" 32#include <algorithm> 33#include <cstring> 34using namespace llvm; 35 36// CreateInfoOutputFile - Return a file stream to print our output on. 37namespace llvm { extern raw_ostream *CreateInfoOutputFile(); } 38 39/// -stats - Command line option to cause transformations to emit stats about 40/// what they did. 41/// 42static cl::opt<bool> 43Enabled("stats", cl::desc("Enable statistics output from program")); 44 45 46namespace { 47/// StatisticInfo - This class is used in a ManagedStatic so that it is created 48/// on demand (when the first statistic is bumped) and destroyed only when 49/// llvm_shutdown is called. We print statistics from the destructor. 50class StatisticInfo { 51 std::vector<const Statistic*> Stats; 52 friend void llvm::PrintStatistics(); 53 friend void llvm::PrintStatistics(raw_ostream &OS); 54public: 55 ~StatisticInfo(); 56 57 void addStatistic(const Statistic *S) { 58 Stats.push_back(S); 59 } 60}; 61} 62 63static ManagedStatic<StatisticInfo> StatInfo; 64static ManagedStatic<sys::SmartMutex<true> > StatLock; 65 66/// RegisterStatistic - The first time a statistic is bumped, this method is 67/// called. 68void Statistic::RegisterStatistic() { 69 // If stats are enabled, inform StatInfo that this statistic should be 70 // printed. 71 sys::SmartScopedLock<true> Writer(*StatLock); 72 if (!Initialized) { 73 if (Enabled) 74 StatInfo->addStatistic(this); 75 76 TsanHappensBefore(this); 77 sys::MemoryFence(); 78 // Remember we have been registered. 79 TsanIgnoreWritesBegin(); 80 Initialized = true; 81 TsanIgnoreWritesEnd(); 82 } 83} 84 85namespace { 86 87struct NameCompare { 88 bool operator()(const Statistic *LHS, const Statistic *RHS) const { 89 int Cmp = std::strcmp(LHS->getName(), RHS->getName()); 90 if (Cmp != 0) return Cmp < 0; 91 92 // Secondary key is the description. 93 return std::strcmp(LHS->getDesc(), RHS->getDesc()) < 0; 94 } 95}; 96 97} 98 99// Print information when destroyed, iff command line option is specified. 100StatisticInfo::~StatisticInfo() { 101 llvm::PrintStatistics(); 102} 103 104void llvm::EnableStatistics() { 105 Enabled.setValue(true); 106} 107 108bool llvm::AreStatisticsEnabled() { 109 return Enabled; 110} 111 112void llvm::PrintStatistics(raw_ostream &OS) { 113 StatisticInfo &Stats = *StatInfo; 114 115 // Figure out how long the biggest Value and Name fields are. 116 unsigned MaxNameLen = 0, MaxValLen = 0; 117 for (size_t i = 0, e = Stats.Stats.size(); i != e; ++i) { 118 MaxValLen = std::max(MaxValLen, 119 (unsigned)utostr(Stats.Stats[i]->getValue()).size()); 120 MaxNameLen = std::max(MaxNameLen, 121 (unsigned)std::strlen(Stats.Stats[i]->getName())); 122 } 123 124 // Sort the fields by name. 125 std::stable_sort(Stats.Stats.begin(), Stats.Stats.end(), NameCompare()); 126 127 // Print out the statistics header... 128 OS << "===" << std::string(73, '-') << "===\n" 129 << " ... Statistics Collected ...\n" 130 << "===" << std::string(73, '-') << "===\n\n"; 131 132 // Print all of the statistics. 133 for (size_t i = 0, e = Stats.Stats.size(); i != e; ++i) 134 OS << format("%*u %-*s - %s\n", 135 MaxValLen, Stats.Stats[i]->getValue(), 136 MaxNameLen, Stats.Stats[i]->getName(), 137 Stats.Stats[i]->getDesc()); 138 139 OS << '\n'; // Flush the output stream. 140 OS.flush(); 141 142} 143 144void llvm::PrintStatistics() { 145 StatisticInfo &Stats = *StatInfo; 146 147 // Statistics not enabled? 148 if (Stats.Stats.empty()) return; 149 150 // Get the stream to write to. 151 raw_ostream &OutStream = *CreateInfoOutputFile(); 152 PrintStatistics(OutStream); 153 delete &OutStream; // Close the file. 154} 155