LLVM  14.0.0git
Statistic.h
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1 //===-- llvm/ADT/Statistic.h - Easy way to expose stats ---------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines the 'Statistic' class, which is designed to be an easy way
10 // to expose various metrics from passes. These statistics are printed at the
11 // end of a run (from llvm_shutdown), when the -stats command line option is
12 // passed on the command line.
13 //
14 // This is useful for reporting information like the number of instructions
15 // simplified, optimized or removed by various transformations, like this:
16 //
17 // static Statistic NumInstsKilled("gcse", "Number of instructions killed");
18 //
19 // Later, in the code: ++NumInstsKilled;
20 //
21 // NOTE: Statistics *must* be declared as global variables.
22 //
23 //===----------------------------------------------------------------------===//
24 
25 #ifndef LLVM_ADT_STATISTIC_H
26 #define LLVM_ADT_STATISTIC_H
27 
28 #include "llvm/Config/llvm-config.h"
29 #include "llvm/Support/Compiler.h"
30 #include <atomic>
31 #include <memory>
32 #include <vector>
33 
34 // Determine whether statistics should be enabled. We must do it here rather
35 // than in CMake because multi-config generators cannot determine this at
36 // configure time.
37 #if !defined(NDEBUG) || LLVM_FORCE_ENABLE_STATS
38 #define LLVM_ENABLE_STATS 1
39 #else
40 #define LLVM_ENABLE_STATS 0
41 #endif
42 
43 namespace llvm {
44 
45 class raw_ostream;
46 class raw_fd_ostream;
47 class StringRef;
48 
50 public:
51  const char *const DebugType;
52  const char *const Name;
53  const char *const Desc;
54 
55  std::atomic<unsigned> Value;
56  std::atomic<bool> Initialized;
57 
58  constexpr TrackingStatistic(const char *DebugType, const char *Name,
59  const char *Desc)
61  Initialized(false) {}
62 
63  const char *getDebugType() const { return DebugType; }
64  const char *getName() const { return Name; }
65  const char *getDesc() const { return Desc; }
66 
67  unsigned getValue() const { return Value.load(std::memory_order_relaxed); }
68 
69  // Allow use of this class as the value itself.
70  operator unsigned() const { return getValue(); }
71 
72  const TrackingStatistic &operator=(unsigned Val) {
73  Value.store(Val, std::memory_order_relaxed);
74  return init();
75  }
76 
78  Value.fetch_add(1, std::memory_order_relaxed);
79  return init();
80  }
81 
82  unsigned operator++(int) {
83  init();
84  return Value.fetch_add(1, std::memory_order_relaxed);
85  }
86 
88  Value.fetch_sub(1, std::memory_order_relaxed);
89  return init();
90  }
91 
92  unsigned operator--(int) {
93  init();
94  return Value.fetch_sub(1, std::memory_order_relaxed);
95  }
96 
97  const TrackingStatistic &operator+=(unsigned V) {
98  if (V == 0)
99  return *this;
100  Value.fetch_add(V, std::memory_order_relaxed);
101  return init();
102  }
103 
104  const TrackingStatistic &operator-=(unsigned V) {
105  if (V == 0)
106  return *this;
107  Value.fetch_sub(V, std::memory_order_relaxed);
108  return init();
109  }
110 
111  void updateMax(unsigned V) {
112  unsigned PrevMax = Value.load(std::memory_order_relaxed);
113  // Keep trying to update max until we succeed or another thread produces
114  // a bigger max than us.
115  while (V > PrevMax && !Value.compare_exchange_weak(
116  PrevMax, V, std::memory_order_relaxed)) {
117  }
118  init();
119  }
120 
121 protected:
123  if (!Initialized.load(std::memory_order_acquire))
125  return *this;
126  }
127 
128  void RegisterStatistic();
129 };
130 
132 public:
133  NoopStatistic(const char * /*DebugType*/, const char * /*Name*/,
134  const char * /*Desc*/) {}
135 
136  unsigned getValue() const { return 0; }
137 
138  // Allow use of this class as the value itself.
139  operator unsigned() const { return 0; }
140 
141  const NoopStatistic &operator=(unsigned Val) { return *this; }
142 
143  const NoopStatistic &operator++() { return *this; }
144 
145  unsigned operator++(int) { return 0; }
146 
147  const NoopStatistic &operator--() { return *this; }
148 
149  unsigned operator--(int) { return 0; }
150 
151  const NoopStatistic &operator+=(const unsigned &V) { return *this; }
152 
153  const NoopStatistic &operator-=(const unsigned &V) { return *this; }
154 
155  void updateMax(unsigned V) {}
156 };
157 
158 #if LLVM_ENABLE_STATS
160 #else
161 using Statistic = NoopStatistic;
162 #endif
163 
164 // STATISTIC - A macro to make definition of statistics really simple. This
165 // automatically passes the DEBUG_TYPE of the file into the statistic.
166 #define STATISTIC(VARNAME, DESC) \
167  static llvm::Statistic VARNAME = {DEBUG_TYPE, #VARNAME, DESC}
168 
169 // ALWAYS_ENABLED_STATISTIC - A macro to define a statistic like STATISTIC but
170 // it is enabled even if LLVM_ENABLE_STATS is off.
171 #define ALWAYS_ENABLED_STATISTIC(VARNAME, DESC) \
172  static llvm::TrackingStatistic VARNAME = {DEBUG_TYPE, #VARNAME, DESC}
173 
174 /// Enable the collection and printing of statistics.
175 void EnableStatistics(bool DoPrintOnExit = true);
176 
177 /// Check if statistics are enabled.
178 bool AreStatisticsEnabled();
179 
180 /// Return a file stream to print our output on.
181 std::unique_ptr<raw_fd_ostream> CreateInfoOutputFile();
182 
183 /// Print statistics to the file returned by CreateInfoOutputFile().
184 void PrintStatistics();
185 
186 /// Print statistics to the given output stream.
187 void PrintStatistics(raw_ostream &OS);
188 
189 /// Print statistics in JSON format. This does include all global timers (\see
190 /// Timer, TimerGroup). Note that the timers are cleared after printing and will
191 /// not be printed in human readable form or in a second call of
192 /// PrintStatisticsJSON().
193 void PrintStatisticsJSON(raw_ostream &OS);
194 
195 /// Get the statistics. This can be used to look up the value of
196 /// statistics without needing to parse JSON.
197 ///
198 /// This function does not prevent statistics being updated by other threads
199 /// during it's execution. It will return the value at the point that it is
200 /// read. However, it will prevent new statistics from registering until it
201 /// completes.
202 const std::vector<std::pair<StringRef, unsigned>> GetStatistics();
203 
204 /// Reset the statistics. This can be used to zero and de-register the
205 /// statistics in order to measure a compilation.
206 ///
207 /// When this function begins to call destructors prior to returning, all
208 /// statistics will be zero and unregistered. However, that might not remain the
209 /// case by the time this function finishes returning. Whether update from other
210 /// threads are lost or merely deferred until during the function return is
211 /// timing sensitive.
212 ///
213 /// Callers who intend to use this to measure statistics for a single
214 /// compilation should ensure that no compilations are in progress at the point
215 /// this function is called and that only one compilation executes until calling
216 /// GetStatistics().
217 void ResetStatistics();
218 
219 } // end namespace llvm
220 
221 #endif // LLVM_ADT_STATISTIC_H
llvm
---------------------— PointerInfo ------------------------------------—
Definition: AllocatorList.h:23
llvm::NoopStatistic::updateMax
void updateMax(unsigned V)
Definition: Statistic.h:155
llvm::NoopStatistic::operator-=
const NoopStatistic & operator-=(const unsigned &V)
Definition: Statistic.h:153
llvm::NoopStatistic::getValue
unsigned getValue() const
Definition: Statistic.h:136
llvm::TrackingStatistic::getDebugType
const char * getDebugType() const
Definition: Statistic.h:63
llvm::TrackingStatistic::operator=
const TrackingStatistic & operator=(unsigned Val)
Definition: Statistic.h:72
llvm::NoopStatistic::NoopStatistic
NoopStatistic(const char *, const char *, const char *)
Definition: Statistic.h:133
llvm::TrackingStatistic::operator-=
const TrackingStatistic & operator-=(unsigned V)
Definition: Statistic.h:104
llvm::CreateInfoOutputFile
std::unique_ptr< raw_fd_ostream > CreateInfoOutputFile()
Return a file stream to print our output on.
Definition: Timer.cpp:96
llvm::GetStatistics
const std::vector< std::pair< StringRef, unsigned > > GetStatistics()
Get the statistics.
Definition: Statistic.cpp:259
llvm::AreStatisticsEnabled
bool AreStatisticsEnabled()
Check if statistics are enabled.
Definition: Statistic.cpp:138
llvm::TrackingStatistic::RegisterStatistic
void RegisterStatistic()
RegisterStatistic - The first time a statistic is bumped, this method is called.
Definition: Statistic.cpp:98
llvm::NoopStatistic
Definition: Statistic.h:131
false
Definition: StackSlotColoring.cpp:142
llvm::TrackingStatistic::operator--
const TrackingStatistic & operator--()
Definition: Statistic.h:87
llvm::TrackingStatistic::getName
const char * getName() const
Definition: Statistic.h:64
llvm::TrackingStatistic::DebugType
const char *const DebugType
Definition: Statistic.h:51
llvm::NoopStatistic::operator--
unsigned operator--(int)
Definition: Statistic.h:149
llvm::TrackingStatistic::getValue
unsigned getValue() const
Definition: Statistic.h:67
llvm::TrackingStatistic::getDesc
const char * getDesc() const
Definition: Statistic.h:65
llvm::TrackingStatistic::Value
std::atomic< unsigned > Value
Definition: Statistic.h:55
llvm::PrintStatisticsJSON
void PrintStatisticsJSON(raw_ostream &OS)
Print statistics in JSON format.
Definition: Statistic.cpp:205
llvm::NoopStatistic::operator+=
const NoopStatistic & operator+=(const unsigned &V)
Definition: Statistic.h:151
llvm::TrackingStatistic::init
TrackingStatistic & init()
Definition: Statistic.h:122
llvm::EnableStatistics
void EnableStatistics(bool DoPrintOnExit=true)
Enable the collection and printing of statistics.
Definition: Statistic.cpp:133
llvm::TrackingStatistic::TrackingStatistic
constexpr TrackingStatistic(const char *DebugType, const char *Name, const char *Desc)
Definition: Statistic.h:58
llvm::PrintStatistics
void PrintStatistics()
Print statistics to the file returned by CreateInfoOutputFile().
Definition: Statistic.cpp:231
llvm::TrackingStatistic::Name
const char *const Name
Definition: Statistic.h:52
llvm::NoopStatistic::operator=
const NoopStatistic & operator=(unsigned Val)
Definition: Statistic.h:141
Compiler.h
llvm::TrackingStatistic::operator--
unsigned operator--(int)
Definition: Statistic.h:92
llvm::TrackingStatistic
Definition: Statistic.h:49
llvm::NoopStatistic::operator++
const NoopStatistic & operator++()
Definition: Statistic.h:143
llvm::TrackingStatistic::Desc
const char *const Desc
Definition: Statistic.h:53
llvm::TrackingStatistic::Initialized
std::atomic< bool > Initialized
Definition: Statistic.h:56
llvm::ResetStatistics
void ResetStatistics()
Reset the statistics.
Definition: Statistic.cpp:268
llvm::TrackingStatistic::updateMax
void updateMax(unsigned V)
Definition: Statistic.h:111
llvm::NoopStatistic::operator++
unsigned operator++(int)
Definition: Statistic.h:145
llvm::NoopStatistic::operator--
const NoopStatistic & operator--()
Definition: Statistic.h:147
llvm::TrackingStatistic::operator+=
const TrackingStatistic & operator+=(unsigned V)
Definition: Statistic.h:97
llvm::Value
LLVM Value Representation.
Definition: Value.h:75
llvm::TrackingStatistic::operator++
const TrackingStatistic & operator++()
Definition: Statistic.h:77
llvm::TrackingStatistic::operator++
unsigned operator++(int)
Definition: Statistic.h:82