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      1 //===-- llvm/Support/Timer.h - Interval Timing Support ----------*- C++ -*-===//
      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 #ifndef LLVM_SUPPORT_TIMER_H
     11 #define LLVM_SUPPORT_TIMER_H
     12 
     13 #include "llvm/ADT/StringRef.h"
     14 #include "llvm/Support/DataTypes.h"
     15 #include <cassert>
     16 #include <string>
     17 #include <utility>
     18 #include <vector>
     19 
     20 namespace llvm {
     21 
     22 class Timer;
     23 class TimerGroup;
     24 class raw_ostream;
     25 
     26 class TimeRecord {
     27   double WallTime;       // Wall clock time elapsed in seconds
     28   double UserTime;       // User time elapsed
     29   double SystemTime;     // System time elapsed
     30   ssize_t MemUsed;       // Memory allocated (in bytes)
     31 public:
     32   TimeRecord() : WallTime(0), UserTime(0), SystemTime(0), MemUsed(0) {}
     33 
     34   /// getCurrentTime - Get the current time and memory usage.  If Start is true
     35   /// we get the memory usage before the time, otherwise we get time before
     36   /// memory usage.  This matters if the time to get the memory usage is
     37   /// significant and shouldn't 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 
     46 
     47   // operator< - Allow sorting.
     48   bool operator<(const TimeRecord &T) const {
     49     // Sort by Wall Time elapsed, as it is the only thing really accurate
     50     return WallTime < T.WallTime;
     51   }
     52 
     53   void operator+=(const TimeRecord &RHS) {
     54     WallTime   += RHS.WallTime;
     55     UserTime   += RHS.UserTime;
     56     SystemTime += RHS.SystemTime;
     57     MemUsed    += RHS.MemUsed;
     58   }
     59   void operator-=(const TimeRecord &RHS) {
     60     WallTime   -= RHS.WallTime;
     61     UserTime   -= RHS.UserTime;
     62     SystemTime -= RHS.SystemTime;
     63     MemUsed    -= RHS.MemUsed;
     64   }
     65 
     66   /// print - Print the current timer to standard error, and reset the "Started"
     67   /// flag.
     68   void print(const TimeRecord &Total, raw_ostream &OS) const;
     69 };
     70 
     71 /// Timer - This class is used to track the amount of time spent between
     72 /// invocations of its startTimer()/stopTimer() methods.  Given appropriate OS
     73 /// support it can also keep track of the RSS of the program at various points.
     74 /// By default, the Timer will print the amount of time it has captured to
     75 /// standard error when the last timer is destroyed, otherwise it is printed
     76 /// when its TimerGroup is destroyed.  Timers do not print their information
     77 /// if they are never started.
     78 ///
     79 class Timer {
     80   TimeRecord Time;
     81   std::string Name;      // The name of this time variable.
     82   bool Started;          // Has this time variable ever been started?
     83   TimerGroup *TG;        // The TimerGroup this Timer is in.
     84 
     85   Timer **Prev, *Next;   // Doubly linked list of timers in the group.
     86 public:
     87   explicit Timer(StringRef N) : TG(nullptr) { init(N); }
     88   Timer(StringRef N, TimerGroup &tg) : TG(nullptr) { init(N, tg); }
     89   Timer(const Timer &RHS) : TG(nullptr) {
     90     assert(!RHS.TG && "Can only copy uninitialized timers");
     91   }
     92   const Timer &operator=(const Timer &T) {
     93     assert(!TG && !T.TG && "Can only assign uninit timers");
     94     return *this;
     95   }
     96   ~Timer();
     97 
     98   // Create an uninitialized timer, client must use 'init'.
     99   explicit Timer() : TG(nullptr) {}
    100   void init(StringRef N);
    101   void init(StringRef N, TimerGroup &tg);
    102 
    103   const std::string &getName() const { return Name; }
    104   bool isInitialized() const { return TG != nullptr; }
    105 
    106   /// startTimer - Start the timer running.  Time between calls to
    107   /// startTimer/stopTimer is counted by the Timer class.  Note that these calls
    108   /// must be correctly paired.
    109   ///
    110   void startTimer();
    111 
    112   /// stopTimer - Stop the timer.
    113   ///
    114   void stopTimer();
    115 
    116 private:
    117   friend class TimerGroup;
    118 };
    119 
    120 
    121 /// The TimeRegion class is used as a helper class to call the startTimer() and
    122 /// stopTimer() methods of the Timer class.  When the object is constructed, it
    123 /// starts the timer specified as its argument.  When it is destroyed, it stops
    124 /// the relevant timer.  This makes it easy to time a region of code.
    125 ///
    126 class TimeRegion {
    127   Timer *T;
    128   TimeRegion(const TimeRegion &) = delete;
    129 public:
    130   explicit TimeRegion(Timer &t) : T(&t) {
    131     T->startTimer();
    132   }
    133   explicit TimeRegion(Timer *t) : T(t) {
    134     if (T) T->startTimer();
    135   }
    136   ~TimeRegion() {
    137     if (T) T->stopTimer();
    138   }
    139 };
    140 
    141 
    142 /// NamedRegionTimer - This class is basically a combination of TimeRegion and
    143 /// Timer.  It allows you to declare a new timer, AND specify the region to
    144 /// time, all in one statement.  All timers with the same name are merged.  This
    145 /// is primarily used for debugging and for hunting performance problems.
    146 ///
    147 struct NamedRegionTimer : public TimeRegion {
    148   explicit NamedRegionTimer(StringRef Name,
    149                             bool Enabled = true);
    150   explicit NamedRegionTimer(StringRef Name, StringRef GroupName,
    151                             bool Enabled = true);
    152 };
    153 
    154 
    155 /// The TimerGroup class is used to group together related timers into a single
    156 /// report that is printed when the TimerGroup is destroyed.  It is illegal to
    157 /// destroy a TimerGroup object before all of the Timers in it are gone.  A
    158 /// TimerGroup can be specified for a newly created timer in its constructor.
    159 ///
    160 class TimerGroup {
    161   std::string Name;
    162   Timer *FirstTimer;   // First timer in the group.
    163   std::vector<std::pair<TimeRecord, std::string> > TimersToPrint;
    164 
    165   TimerGroup **Prev, *Next; // Doubly linked list of TimerGroup's.
    166   TimerGroup(const TimerGroup &TG) = delete;
    167   void operator=(const TimerGroup &TG) = delete;
    168 public:
    169   explicit TimerGroup(StringRef name);
    170   ~TimerGroup();
    171 
    172   void setName(StringRef name) { Name.assign(name.begin(), name.end()); }
    173 
    174   /// print - Print any started timers in this group and zero them.
    175   void print(raw_ostream &OS);
    176 
    177   /// printAll - This static method prints all timers and clears them all out.
    178   static void printAll(raw_ostream &OS);
    179 
    180 private:
    181   friend class Timer;
    182   void addTimer(Timer &T);
    183   void removeTimer(Timer &T);
    184   void PrintQueuedTimers(raw_ostream &OS);
    185 };
    186 
    187 } // End llvm namespace
    188 
    189 #endif
    190