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 sys::MemoryFence(); 77 // Remember we have been registered. 78 Initialized = true; 79 } 80 } 81 82 namespace { 83 84 struct NameCompare { 85 bool operator()(const Statistic *LHS, const Statistic *RHS) const { 86 int Cmp = std::strcmp(LHS->getName(), RHS->getName()); 87 if (Cmp != 0) return Cmp < 0; 88 89 // Secondary key is the description. 90 return std::strcmp(LHS->getDesc(), RHS->getDesc()) < 0; 91 } 92 }; 93 94 } 95 96 // Print information when destroyed, iff command line option is specified. 97 StatisticInfo::~StatisticInfo() { 98 llvm::PrintStatistics(); 99 } 100 101 void llvm::EnableStatistics() { 102 Enabled.setValue(true); 103 } 104 105 bool llvm::AreStatisticsEnabled() { 106 return Enabled; 107 } 108 109 void llvm::PrintStatistics(raw_ostream &OS) { 110 StatisticInfo &Stats = *StatInfo; 111 112 // Figure out how long the biggest Value and Name fields are. 113 unsigned MaxNameLen = 0, MaxValLen = 0; 114 for (size_t i = 0, e = Stats.Stats.size(); i != e; ++i) { 115 MaxValLen = std::max(MaxValLen, 116 (unsigned)utostr(Stats.Stats[i]->getValue()).size()); 117 MaxNameLen = std::max(MaxNameLen, 118 (unsigned)std::strlen(Stats.Stats[i]->getName())); 119 } 120 121 // Sort the fields by name. 122 std::stable_sort(Stats.Stats.begin(), Stats.Stats.end(), NameCompare()); 123 124 // Print out the statistics header... 125 OS << "===" << std::string(73, '-') << "===\n" 126 << " ... Statistics Collected ...\n" 127 << "===" << std::string(73, '-') << "===\n\n"; 128 129 // Print all of the statistics. 130 for (size_t i = 0, e = Stats.Stats.size(); i != e; ++i) 131 OS << format("%*u %-*s - %s\n", 132 MaxValLen, Stats.Stats[i]->getValue(), 133 MaxNameLen, Stats.Stats[i]->getName(), 134 Stats.Stats[i]->getDesc()); 135 136 OS << '\n'; // Flush the output stream. 137 OS.flush(); 138 139 } 140 141 void llvm::PrintStatistics() { 142 StatisticInfo &Stats = *StatInfo; 143 144 // Statistics not enabled? 145 if (Stats.Stats.empty()) return; 146 147 // Get the stream to write to. 148 raw_ostream &OutStream = *CreateInfoOutputFile(); 149 PrintStatistics(OutStream); 150 delete &OutStream; // Close the file. 151 } 152