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> 34 using namespace llvm; 35 36 // CreateInfoOutputFile - Return a file stream to print our output on. 37 namespace llvm { extern raw_ostream *CreateInfoOutputFile(); } 38 39 /// -stats - Command line option to cause transformations to emit stats about 40 /// what they did. 41 /// 42 static cl::opt<bool> 43 Enabled("stats", cl::desc("Enable statistics output from program")); 44 45 46 namespace { 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. 50 class StatisticInfo { 51 std::vector<const Statistic*> Stats; 52 friend void llvm::PrintStatistics(); 53 friend void llvm::PrintStatistics(raw_ostream &OS); 54 public: 55 ~StatisticInfo(); 56 57 void addStatistic(const Statistic *S) { 58 Stats.push_back(S); 59 } 60 }; 61 } 62 63 static ManagedStatic<StatisticInfo> StatInfo; 64 static ManagedStatic<sys::SmartMutex<true> > StatLock; 65 66 /// RegisterStatistic - The first time a statistic is bumped, this method is 67 /// called. 68 void 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 85 namespace { 86 87 struct 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. 100 StatisticInfo::~StatisticInfo() { 101 llvm::PrintStatistics(); 102 } 103 104 void llvm::EnableStatistics() { 105 Enabled.setValue(true); 106 } 107 108 bool llvm::AreStatisticsEnabled() { 109 return Enabled; 110 } 111 112 void 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 } 143 144 void 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