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/ManagedStatic.h"
28 #include "llvm/Support/raw_ostream.h"
29 #include "llvm/Support/Mutex.h"
30 #include "llvm/ADT/StringExtras.h"
31 #include <algorithm>
32 #include <cstring>
33 using namespace llvm;
34
35 // CreateInfoOutputFile - Return a file stream to print our output on.
36 namespace llvm { extern raw_ostream *CreateInfoOutputFile(); }
37
38 /// -stats - Command line option to cause transformations to emit stats about
39 /// what they did.
40 ///
41 static cl::opt<bool>
42 Enabled("stats", cl::desc("Enable statistics output from program"));
43
44
45 namespace {
46 /// StatisticInfo - This class is used in a ManagedStatic so that it is created
47 /// on demand (when the first statistic is bumped) and destroyed only when
48 /// llvm_shutdown is called. We print statistics from the destructor.
49 class StatisticInfo {
50 std::vector<const Statistic*> Stats;
51 friend void llvm::PrintStatistics();
52 friend void llvm::PrintStatistics(raw_ostream &OS);
53 public:
54 ~StatisticInfo();
55
addStatistic(const Statistic * S)56 void addStatistic(const Statistic *S) {
57 Stats.push_back(S);
58 }
59 };
60 }
61
62 static ManagedStatic<StatisticInfo> StatInfo;
63 static ManagedStatic<sys::SmartMutex<true> > StatLock;
64
65 /// RegisterStatistic - The first time a statistic is bumped, this method is
66 /// called.
RegisterStatistic()67 void Statistic::RegisterStatistic() {
68 // If stats are enabled, inform StatInfo that this statistic should be
69 // printed.
70 sys::SmartScopedLock<true> Writer(*StatLock);
71 if (!Initialized) {
72 if (Enabled)
73 StatInfo->addStatistic(this);
74
75 sys::MemoryFence();
76 // Remember we have been registered.
77 Initialized = true;
78 }
79 }
80
81 namespace {
82
83 struct NameCompare {
operator ()__anon320f85390211::NameCompare84 bool operator()(const Statistic *LHS, const Statistic *RHS) const {
85 int Cmp = std::strcmp(LHS->getName(), RHS->getName());
86 if (Cmp != 0) return Cmp < 0;
87
88 // Secondary key is the description.
89 return std::strcmp(LHS->getDesc(), RHS->getDesc()) < 0;
90 }
91 };
92
93 }
94
95 // Print information when destroyed, iff command line option is specified.
~StatisticInfo()96 StatisticInfo::~StatisticInfo() {
97 llvm::PrintStatistics();
98 }
99
EnableStatistics()100 void llvm::EnableStatistics() {
101 Enabled.setValue(true);
102 }
103
AreStatisticsEnabled()104 bool llvm::AreStatisticsEnabled() {
105 return Enabled;
106 }
107
PrintStatistics(raw_ostream & OS)108 void llvm::PrintStatistics(raw_ostream &OS) {
109 StatisticInfo &Stats = *StatInfo;
110
111 // Figure out how long the biggest Value and Name fields are.
112 unsigned MaxNameLen = 0, MaxValLen = 0;
113 for (size_t i = 0, e = Stats.Stats.size(); i != e; ++i) {
114 MaxValLen = std::max(MaxValLen,
115 (unsigned)utostr(Stats.Stats[i]->getValue()).size());
116 MaxNameLen = std::max(MaxNameLen,
117 (unsigned)std::strlen(Stats.Stats[i]->getName()));
118 }
119
120 // Sort the fields by name.
121 std::stable_sort(Stats.Stats.begin(), Stats.Stats.end(), NameCompare());
122
123 // Print out the statistics header...
124 OS << "===" << std::string(73, '-') << "===\n"
125 << " ... Statistics Collected ...\n"
126 << "===" << std::string(73, '-') << "===\n\n";
127
128 // Print all of the statistics.
129 for (size_t i = 0, e = Stats.Stats.size(); i != e; ++i) {
130 std::string CountStr = utostr(Stats.Stats[i]->getValue());
131 OS << std::string(MaxValLen-CountStr.size(), ' ')
132 << CountStr << " " << Stats.Stats[i]->getName()
133 << std::string(MaxNameLen-std::strlen(Stats.Stats[i]->getName()), ' ')
134 << " - " << Stats.Stats[i]->getDesc() << "\n";
135 }
136
137 OS << '\n'; // Flush the output stream.
138 OS.flush();
139
140 }
141
PrintStatistics()142 void llvm::PrintStatistics() {
143 StatisticInfo &Stats = *StatInfo;
144
145 // Statistics not enabled?
146 if (Stats.Stats.empty()) return;
147
148 // Get the stream to write to.
149 raw_ostream &OutStream = *CreateInfoOutputFile();
150 PrintStatistics(OutStream);
151 delete &OutStream; // Close the file.
152 }
153