1 //===-- Statistic.cpp - Easy way to expose stats information --------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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.
15 // This is useful for reporting information like the number of instructions
16 // simplified, optimized or removed by various transformations, like this:
18 // static Statistic NumInstEliminated("GCSE", "Number of instructions killed");
20 // Later, in the code: ++NumInstEliminated;
22 //===----------------------------------------------------------------------===//
24 #include "llvm/ADT/Statistic.h"
25 #include "llvm/ADT/StringExtras.h"
26 #include "llvm/Support/CommandLine.h"
27 #include "llvm/Support/Compiler.h"
28 #include "llvm/Support/Debug.h"
29 #include "llvm/Support/Format.h"
30 #include "llvm/Support/ManagedStatic.h"
31 #include "llvm/Support/Mutex.h"
32 #include "llvm/Support/raw_ostream.h"
37 // CreateInfoOutputFile - Return a file stream to print our output on.
38 namespace llvm { extern raw_ostream *CreateInfoOutputFile(); }
40 /// -stats - Command line option to cause transformations to emit stats about
46 cl::desc("Enable statistics output from program (available with Asserts)"));
50 /// StatisticInfo - This class is used in a ManagedStatic so that it is created
51 /// on demand (when the first statistic is bumped) and destroyed only when
52 /// llvm_shutdown is called. We print statistics from the destructor.
54 std::vector<const Statistic*> Stats;
55 friend void llvm::PrintStatistics();
56 friend void llvm::PrintStatistics(raw_ostream &OS);
60 void addStatistic(const Statistic *S) {
66 static ManagedStatic<StatisticInfo> StatInfo;
67 static ManagedStatic<sys::SmartMutex<true> > StatLock;
69 /// RegisterStatistic - The first time a statistic is bumped, this method is
71 void Statistic::RegisterStatistic() {
72 // If stats are enabled, inform StatInfo that this statistic should be
74 sys::SmartScopedLock<true> Writer(*StatLock);
77 StatInfo->addStatistic(this);
79 TsanHappensBefore(this);
81 // Remember we have been registered.
82 TsanIgnoreWritesBegin();
84 TsanIgnoreWritesEnd();
88 // Print information when destroyed, iff command line option is specified.
89 StatisticInfo::~StatisticInfo() {
90 llvm::PrintStatistics();
93 void llvm::EnableStatistics() {
94 Enabled.setValue(true);
97 bool llvm::AreStatisticsEnabled() {
101 void llvm::PrintStatistics(raw_ostream &OS) {
102 StatisticInfo &Stats = *StatInfo;
104 // Figure out how long the biggest Value and Name fields are.
105 unsigned MaxNameLen = 0, MaxValLen = 0;
106 for (size_t i = 0, e = Stats.Stats.size(); i != e; ++i) {
107 MaxValLen = std::max(MaxValLen,
108 (unsigned)utostr(Stats.Stats[i]->getValue()).size());
109 MaxNameLen = std::max(MaxNameLen,
110 (unsigned)std::strlen(Stats.Stats[i]->getName()));
113 // Sort the fields by name.
114 std::stable_sort(Stats.Stats.begin(), Stats.Stats.end(),
115 [](const Statistic *LHS, const Statistic *RHS) {
116 if (int Cmp = std::strcmp(LHS->getName(), RHS->getName()))
119 // Secondary key is the description.
120 return std::strcmp(LHS->getDesc(), RHS->getDesc()) < 0;
123 // Print out the statistics header...
124 OS << "===" << std::string(73, '-') << "===\n"
125 << " ... Statistics Collected ...\n"
126 << "===" << std::string(73, '-') << "===\n\n";
128 // Print all of the statistics.
129 for (size_t i = 0, e = Stats.Stats.size(); i != e; ++i)
130 OS << format("%*u %-*s - %s\n",
131 MaxValLen, Stats.Stats[i]->getValue(),
132 MaxNameLen, Stats.Stats[i]->getName(),
133 Stats.Stats[i]->getDesc());
135 OS << '\n'; // Flush the output stream.
140 void llvm::PrintStatistics() {
141 #if !defined(NDEBUG) || defined(LLVM_ENABLE_STATS)
142 StatisticInfo &Stats = *StatInfo;
144 // Statistics not enabled?
145 if (Stats.Stats.empty()) return;
147 // Get the stream to write to.
148 raw_ostream &OutStream = *CreateInfoOutputFile();
149 PrintStatistics(OutStream);
150 delete &OutStream; // Close the file.
152 // Check if the -stats option is set instead of checking
153 // !Stats.Stats.empty(). In release builds, Statistics operators
154 // do nothing, so stats are never Registered.
156 // Get the stream to write to.
157 raw_ostream &OutStream = *CreateInfoOutputFile();
158 OutStream << "Statistics are disabled. "
159 << "Build with asserts or with -DLLVM_ENABLE_STATS\n";
161 delete &OutStream; // Close the file.