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/Support/CommandLine.h"
26 #include "llvm/Support/ManagedStatic.h"
27 #include "llvm/Support/Streams.h"
28 #include "llvm/ADT/StringExtras.h"
34 // GetLibSupportInfoOutputFile - Return a file stream to print our output on.
35 namespace llvm { extern std::ostream *GetLibSupportInfoOutputFile(); }
37 /// -stats - Command line option to cause transformations to emit stats about
41 Enabled("stats", cl::desc("Enable statistics output from program"));
45 /// StatisticInfo - This class is used in a ManagedStatic so that it is created
46 /// on demand (when the first statistic is bumped) and destroyed only when
47 /// llvm_shutdown is called. We print statistics from the destructor.
49 std::vector<const Statistic*> Stats;
53 void addStatistic(const Statistic *S) {
59 static ManagedStatic<StatisticInfo> StatInfo;
62 /// RegisterStatistic - The first time a statistic is bumped, this method is
64 void Statistic::RegisterStatistic() {
65 // If stats are enabled, inform StatInfo that this statistic should be
68 StatInfo->addStatistic(this);
69 // Remember we have been registered.
74 bool operator()(const Statistic *LHS, const Statistic *RHS) const {
75 int Cmp = std::strcmp(LHS->getName(), RHS->getName());
76 if (Cmp != 0) return Cmp < 0;
78 // Secondary key is the description.
79 return std::strcmp(LHS->getDesc(), RHS->getDesc()) < 0;
83 // Print information when destroyed, iff command line option is specified.
84 StatisticInfo::~StatisticInfo() {
85 // Statistics not enabled?
86 if (Stats.empty()) return;
88 // Get the stream to write to.
89 std::ostream &OutStream = *GetLibSupportInfoOutputFile();
91 // Figure out how long the biggest Value and Name fields are.
92 unsigned MaxNameLen = 0, MaxValLen = 0;
93 for (unsigned i = 0, e = Stats.size(); i != e; ++i) {
94 MaxValLen = std::max(MaxValLen,
95 (unsigned)utostr(Stats[i]->getValue()).size());
96 MaxNameLen = std::max(MaxNameLen,
97 (unsigned)std::strlen(Stats[i]->getName()));
100 // Sort the fields by name.
101 std::stable_sort(Stats.begin(), Stats.end(), NameCompare());
103 // Print out the statistics header...
104 OutStream << "===" << std::string(73, '-') << "===\n"
105 << " ... Statistics Collected ...\n"
106 << "===" << std::string(73, '-') << "===\n\n";
108 // Print all of the statistics.
109 for (unsigned i = 0, e = Stats.size(); i != e; ++i) {
110 std::string CountStr = utostr(Stats[i]->getValue());
111 OutStream << std::string(MaxValLen-CountStr.size(), ' ')
112 << CountStr << " " << Stats[i]->getName()
113 << std::string(MaxNameLen-std::strlen(Stats[i]->getName()), ' ')
114 << " - " << Stats[i]->getDesc() << "\n";
118 OutStream << std::endl; // Flush the output stream...
120 if (&OutStream != cerr.stream() && &OutStream != cout.stream())
121 delete &OutStream; // Close the file.