1//===-- llvm/Support/Timer.h - Interval Timing Support ----------*- 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#ifndef LLVM_SUPPORT_TIMER_H
10#define LLVM_SUPPORT_TIMER_H
11
12#include "llvm/ADT/StringMap.h"
13#include "llvm/ADT/StringRef.h"
14#include "llvm/Support/DataTypes.h"
15#include <cassert>
16#include <memory>
17#include <string>
18#include <vector>
19
20namespace llvm {
21
22class TimerGroup;
23class raw_ostream;
24
25class TimeRecord {
26  double WallTime = 0.0;             ///< Wall clock time elapsed in seconds.
27  double UserTime = 0.0;             ///< User time elapsed.
28  double SystemTime = 0.0;           ///< System time elapsed.
29  ssize_t MemUsed = 0;               ///< Memory allocated (in bytes).
30  uint64_t InstructionsExecuted = 0; ///< Number of instructions executed
31public:
32  TimeRecord() = default;
33
34  /// Get the current time and memory usage.  If Start is true we get the memory
35  /// usage before the time, otherwise we get time before memory usage.  This
36  /// matters if the time to get the memory usage is significant and shouldn't
37  /// be counted as part of a duration.
38  static TimeRecord getCurrentTime(bool Start = true);
39
40  double getProcessTime() const { return UserTime + SystemTime; }
41  double getUserTime() const { return UserTime; }
42  double getSystemTime() const { return SystemTime; }
43  double getWallTime() const { return WallTime; }
44  ssize_t getMemUsed() const { return MemUsed; }
45  uint64_t getInstructionsExecuted() const { return InstructionsExecuted; }
46
47  bool operator<(const TimeRecord &T) const {
48    // Sort by Wall Time elapsed, as it is the only thing really accurate
49    return WallTime < T.WallTime;
50  }
51
52  void operator+=(const TimeRecord &RHS) {
53    WallTime += RHS.WallTime;
54    UserTime += RHS.UserTime;
55    SystemTime += RHS.SystemTime;
56    MemUsed += RHS.MemUsed;
57    InstructionsExecuted += RHS.InstructionsExecuted;
58  }
59  void operator-=(const TimeRecord &RHS) {
60    WallTime -= RHS.WallTime;
61    UserTime -= RHS.UserTime;
62    SystemTime -= RHS.SystemTime;
63    MemUsed -= RHS.MemUsed;
64    InstructionsExecuted -= RHS.InstructionsExecuted;
65  }
66
67  /// Print the current time record to \p OS, with a breakdown showing
68  /// contributions to the \p Total time record.
69  void print(const TimeRecord &Total, raw_ostream &OS) const;
70};
71
72/// This class is used to track the amount of time spent between invocations of
73/// its startTimer()/stopTimer() methods.  Given appropriate OS support it can
74/// also keep track of the RSS of the program at various points.  By default,
75/// the Timer will print the amount of time it has captured to standard error
76/// when the last timer is destroyed, otherwise it is printed when its
77/// TimerGroup is destroyed.  Timers do not print their information if they are
78/// never started.
79class Timer {
80  TimeRecord Time;          ///< The total time captured.
81  TimeRecord StartTime;     ///< The time startTimer() was last called.
82  std::string Name;         ///< The name of this time variable.
83  std::string Description;  ///< Description of this time variable.
84  bool Running = false;     ///< Is the timer currently running?
85  bool Triggered = false;   ///< Has the timer ever been triggered?
86  TimerGroup *TG = nullptr; ///< The TimerGroup this Timer is in.
87
88  Timer **Prev = nullptr;   ///< Pointer to \p Next of previous timer in group.
89  Timer *Next = nullptr;    ///< Next timer in the group.
90public:
91  explicit Timer(StringRef TimerName, StringRef TimerDescription) {
92    init(TimerName, TimerDescription);
93  }
94  Timer(StringRef TimerName, StringRef TimerDescription, TimerGroup &tg) {
95    init(TimerName, TimerDescription, tg);
96  }
97  Timer(const Timer &RHS) {
98    assert(!RHS.TG && "Can only copy uninitialized timers");
99  }
100  const Timer &operator=(const Timer &T) {
101    assert(!TG && !T.TG && "Can only assign uninit timers");
102    return *this;
103  }
104  ~Timer();
105
106  /// Create an uninitialized timer, client must use 'init'.
107  explicit Timer() = default;
108  void init(StringRef TimerName, StringRef TimerDescription);
109  void init(StringRef TimerName, StringRef TimerDescription, TimerGroup &tg);
110
111  const std::string &getName() const { return Name; }
112  const std::string &getDescription() const { return Description; }
113  bool isInitialized() const { return TG != nullptr; }
114
115  /// Check if the timer is currently running.
116  bool isRunning() const { return Running; }
117
118  /// Check if startTimer() has ever been called on this timer.
119  bool hasTriggered() const { return Triggered; }
120
121  /// Start the timer running.  Time between calls to startTimer/stopTimer is
122  /// counted by the Timer class.  Note that these calls must be correctly
123  /// paired.
124  void startTimer();
125
126  /// Stop the timer.
127  void stopTimer();
128
129  /// Clear the timer state.
130  void clear();
131
132  /// Return the duration for which this timer has been running.
133  TimeRecord getTotalTime() const { return Time; }
134
135private:
136  friend class TimerGroup;
137};
138
139/// The TimeRegion class is used as a helper class to call the startTimer() and
140/// stopTimer() methods of the Timer class.  When the object is constructed, it
141/// starts the timer specified as its argument.  When it is destroyed, it stops
142/// the relevant timer.  This makes it easy to time a region of code.
143class TimeRegion {
144  Timer *T;
145  TimeRegion(const TimeRegion &) = delete;
146
147public:
148  explicit TimeRegion(Timer &t) : T(&t) {
149    T->startTimer();
150  }
151  explicit TimeRegion(Timer *t) : T(t) {
152    if (T) T->startTimer();
153  }
154  ~TimeRegion() {
155    if (T) T->stopTimer();
156  }
157};
158
159/// This class is basically a combination of TimeRegion and Timer.  It allows
160/// you to declare a new timer, AND specify the region to time, all in one
161/// statement.  All timers with the same name are merged.  This is primarily
162/// used for debugging and for hunting performance problems.
163struct NamedRegionTimer : public TimeRegion {
164  explicit NamedRegionTimer(StringRef Name, StringRef Description,
165                            StringRef GroupName,
166                            StringRef GroupDescription, bool Enabled = true);
167};
168
169/// The TimerGroup class is used to group together related timers into a single
170/// report that is printed when the TimerGroup is destroyed.  It is illegal to
171/// destroy a TimerGroup object before all of the Timers in it are gone.  A
172/// TimerGroup can be specified for a newly created timer in its constructor.
173class TimerGroup {
174  struct PrintRecord {
175    TimeRecord Time;
176    std::string Name;
177    std::string Description;
178
179    PrintRecord(const PrintRecord &Other) = default;
180    PrintRecord &operator=(const PrintRecord &Other) = default;
181    PrintRecord(const TimeRecord &Time, const std::string &Name,
182                const std::string &Description)
183      : Time(Time), Name(Name), Description(Description) {}
184
185    bool operator <(const PrintRecord &Other) const {
186      return Time < Other.Time;
187    }
188  };
189  std::string Name;
190  std::string Description;
191  Timer *FirstTimer = nullptr; ///< First timer in the group.
192  std::vector<PrintRecord> TimersToPrint;
193
194  TimerGroup **Prev; ///< Pointer to Next field of previous timergroup in list.
195  TimerGroup *Next;  ///< Pointer to next timergroup in list.
196  TimerGroup(const TimerGroup &TG) = delete;
197  void operator=(const TimerGroup &TG) = delete;
198
199public:
200  explicit TimerGroup(StringRef Name, StringRef Description);
201
202  explicit TimerGroup(StringRef Name, StringRef Description,
203                      const StringMap<TimeRecord> &Records);
204
205  ~TimerGroup();
206
207  void setName(StringRef NewName, StringRef NewDescription) {
208    Name.assign(NewName.begin(), NewName.end());
209    Description.assign(NewDescription.begin(), NewDescription.end());
210  }
211
212  /// Print any started timers in this group, optionally resetting timers after
213  /// printing them.
214  void print(raw_ostream &OS, bool ResetAfterPrint = false);
215
216  /// Clear all timers in this group.
217  void clear();
218
219  /// This static method prints all timers.
220  static void printAll(raw_ostream &OS);
221
222  /// Clear out all timers. This is mostly used to disable automatic
223  /// printing on shutdown, when timers have already been printed explicitly
224  /// using \c printAll or \c printJSONValues.
225  static void clearAll();
226
227  const char *printJSONValues(raw_ostream &OS, const char *delim);
228
229  /// Prints all timers as JSON key/value pairs.
230  static const char *printAllJSONValues(raw_ostream &OS, const char *delim);
231
232  /// Ensure global objects required for statistics printing are initialized.
233  /// This function is used by the Statistic code to ensure correct order of
234  /// global constructors and destructors.
235  static void constructForStatistics();
236
237  /// This makes the default group unmanaged, and lets the user manage the
238  /// group's lifetime.
239  static std::unique_ptr<TimerGroup> aquireDefaultGroup();
240
241private:
242  friend class Timer;
243  friend void PrintStatisticsJSON(raw_ostream &OS);
244  void addTimer(Timer &T);
245  void removeTimer(Timer &T);
246  void prepareToPrintList(bool reset_time = false);
247  void PrintQueuedTimers(raw_ostream &OS);
248  void printJSONValue(raw_ostream &OS, const PrintRecord &R,
249                      const char *suffix, double Value);
250};
251
252} // end namespace llvm
253
254#endif
255