LLVM  3.7.0
Statistic.cpp
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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/ADT/StringExtras.h"
27 #include "llvm/Support/Debug.h"
28 #include "llvm/Support/Format.h"
30 #include "llvm/Support/Mutex.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(
44  "stats",
45  cl::desc("Enable statistics output from program (available with Asserts)"));
46 
47 
48 namespace {
49 /// StatisticInfo - This class is used in a ManagedStatic so that it is created
50 /// on demand (when the first statistic is bumped) and destroyed only when
51 /// llvm_shutdown is called. We print statistics from the destructor.
52 class StatisticInfo {
53  std::vector<const Statistic*> Stats;
54  friend void llvm::PrintStatistics();
55  friend void llvm::PrintStatistics(raw_ostream &OS);
56 public:
57  ~StatisticInfo();
58 
59  void addStatistic(const Statistic *S) {
60  Stats.push_back(S);
61  }
62 };
63 }
64 
67 
68 /// RegisterStatistic - The first time a statistic is bumped, this method is
69 /// called.
71  // If stats are enabled, inform StatInfo that this statistic should be
72  // printed.
74  if (!Initialized) {
75  if (Enabled)
76  StatInfo->addStatistic(this);
77 
78  TsanHappensBefore(this);
80  // Remember we have been registered.
82  Initialized = true;
84  }
85 }
86 
87 // Print information when destroyed, iff command line option is specified.
88 StatisticInfo::~StatisticInfo() {
90 }
91 
93  Enabled.setValue(true);
94 }
95 
97  return Enabled;
98 }
99 
101  StatisticInfo &Stats = *StatInfo;
102 
103  // Figure out how long the biggest Value and Name fields are.
104  unsigned MaxNameLen = 0, MaxValLen = 0;
105  for (size_t i = 0, e = Stats.Stats.size(); i != e; ++i) {
106  MaxValLen = std::max(MaxValLen,
107  (unsigned)utostr(Stats.Stats[i]->getValue()).size());
108  MaxNameLen = std::max(MaxNameLen,
109  (unsigned)std::strlen(Stats.Stats[i]->getName()));
110  }
111 
112  // Sort the fields by name.
113  std::stable_sort(Stats.Stats.begin(), Stats.Stats.end(),
114  [](const Statistic *LHS, const Statistic *RHS) {
115  if (int Cmp = std::strcmp(LHS->getName(), RHS->getName()))
116  return Cmp < 0;
117 
118  // Secondary key is the description.
119  return std::strcmp(LHS->getDesc(), RHS->getDesc()) < 0;
120  });
121 
122  // Print out the statistics header...
123  OS << "===" << std::string(73, '-') << "===\n"
124  << " ... Statistics Collected ...\n"
125  << "===" << std::string(73, '-') << "===\n\n";
126 
127  // Print all of the statistics.
128  for (size_t i = 0, e = Stats.Stats.size(); i != e; ++i)
129  OS << format("%*u %-*s - %s\n",
130  MaxValLen, Stats.Stats[i]->getValue(),
131  MaxNameLen, Stats.Stats[i]->getName(),
132  Stats.Stats[i]->getDesc());
133 
134  OS << '\n'; // Flush the output stream.
135  OS.flush();
136 
137 }
138 
140 #if !defined(NDEBUG) || defined(LLVM_ENABLE_STATS)
141  StatisticInfo &Stats = *StatInfo;
142 
143  // Statistics not enabled?
144  if (Stats.Stats.empty()) return;
145 
146  // Get the stream to write to.
147  raw_ostream &OutStream = *CreateInfoOutputFile();
148  PrintStatistics(OutStream);
149  delete &OutStream; // Close the file.
150 #else
151  // Check if the -stats option is set instead of checking
152  // !Stats.Stats.empty(). In release builds, Statistics operators
153  // do nothing, so stats are never Registered.
154  if (Enabled) {
155  // Get the stream to write to.
156  raw_ostream &OutStream = *CreateInfoOutputFile();
157  OutStream << "Statistics are disabled. "
158  << "Build with asserts or with -DLLVM_ENABLE_STATS\n";
159  OutStream.flush();
160  delete &OutStream; // Close the file.
161  }
162 #endif
163 }
bool Initialized
Definition: Statistic.h:40
void RegisterStatistic()
RegisterStatistic - The first time a statistic is bumped, this method is called.
Definition: Statistic.cpp:70
#define TsanHappensBefore(cv)
Definition: Valgrind.h:50
block placement Basic Block Placement Stats
static cl::opt< bool > Enabled("stats", cl::desc("Enable statistics output from program (available with Asserts)"))
-stats - Command line option to cause transformations to emit stats about what they did...
void EnableStatistics()
Enable the collection and printing of statistics.
Definition: Statistic.cpp:92
static ManagedStatic< StatisticInfo > StatInfo
Definition: Statistic.cpp:65
static std::string utostr(uint64_t X, bool isNeg=false)
Definition: StringExtras.h:93
format_object< Ts...> format(const char *Fmt, const Ts &...Vals)
These are helper functions used to produce formatted output.
Definition: Format.h:111
void MemoryFence()
Definition: Atomic.cpp:29
const char * getDesc() const
Definition: Statistic.h:44
#define TsanIgnoreWritesEnd()
Definition: Valgrind.h:62
const char * getName() const
Definition: Statistic.h:43
raw_ostream * CreateInfoOutputFile()
Definition: Timer.cpp:56
void size_t size
#define TsanIgnoreWritesBegin()
Definition: Valgrind.h:58
void PrintStatistics()
Print statistics to the file returned by CreateInfoOutputFile().
Definition: Statistic.cpp:139
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:38
ManagedStatic - This transparently changes the behavior of global statics to be lazily constructed on...
Definition: ManagedStatic.h:61
static ManagedStatic< sys::SmartMutex< true > > StatLock
Definition: Statistic.cpp:66
bool AreStatisticsEnabled()
Check if statistics are enabled.
Definition: Statistic.cpp:96