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//===-- llvm/Support/Timer.h - Interval Timing Support ----------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/DataTypes.h"
#include <cassert>
#include <string>
#include <utility>
#include <vector>
namespace llvm {
class Timer;
class TimerGroup;
class raw_ostream;
class TimeRecord {
double WallTime; ///< Wall clock time elapsed in seconds.
double UserTime; ///< User time elapsed.
double SystemTime; ///< System time elapsed.
ssize_t MemUsed; ///< Memory allocated (in bytes).
TimeRecord() : WallTime(0), UserTime(0), SystemTime(0), MemUsed(0) {}
/// Get the current time and memory usage. If Start is true we get the memory
/// usage before the time, otherwise we get time before memory usage. This
/// matters if the time to get the memory usage is significant and shouldn't
/// be counted as part of a duration.
static TimeRecord getCurrentTime(bool Start = true);
double getProcessTime() const { return UserTime + SystemTime; }
double getUserTime() const { return UserTime; }
double getSystemTime() const { return SystemTime; }
double getWallTime() const { return WallTime; }
ssize_t getMemUsed() const { return MemUsed; }
bool operator<(const TimeRecord &T) const {
// Sort by Wall Time elapsed, as it is the only thing really accurate
return WallTime < T.WallTime;
void operator+=(const TimeRecord &RHS) {
WallTime += RHS.WallTime;
UserTime += RHS.UserTime;
SystemTime += RHS.SystemTime;
MemUsed += RHS.MemUsed;
void operator-=(const TimeRecord &RHS) {
WallTime -= RHS.WallTime;
UserTime -= RHS.UserTime;
SystemTime -= RHS.SystemTime;
MemUsed -= RHS.MemUsed;
/// Print the current time record to \p OS, with a breakdown showing
/// contributions to the \p Total time record.
void print(const TimeRecord &Total, raw_ostream &OS) const;
/// This class is used to track the amount of time spent between invocations of
/// its startTimer()/stopTimer() methods. Given appropriate OS support it can
/// also keep track of the RSS of the program at various points. By default,
/// the Timer will print the amount of time it has captured to standard error
/// when the last timer is destroyed, otherwise it is printed when its
/// TimerGroup is destroyed. Timers do not print their information if they are
/// never started.
class Timer {
TimeRecord Time; ///< The total time captured.
TimeRecord StartTime; ///< The time startTimer() was last called.
std::string Name; ///< The name of this time variable.
std::string Description; ///< Description of this time variable.
bool Running; ///< Is the timer currently running?
bool Triggered; ///< Has the timer ever been triggered?
TimerGroup *TG = nullptr; ///< The TimerGroup this Timer is in.
Timer **Prev; ///< Pointer to \p Next of previous timer in group.
Timer *Next; ///< Next timer in the group.
explicit Timer(StringRef Name, StringRef Description) {
init(Name, Description);
Timer(StringRef Name, StringRef Description, TimerGroup &tg) {
init(Name, Description, tg);
Timer(const Timer &RHS) {
assert(!RHS.TG && "Can only copy uninitialized timers");
const Timer &operator=(const Timer &T) {
assert(!TG && !T.TG && "Can only assign uninit timers");
return *this;
/// Create an uninitialized timer, client must use 'init'.
explicit Timer() {}
void init(StringRef Name, StringRef Description);
void init(StringRef Name, StringRef Description, TimerGroup &tg);
const std::string &getName() const { return Name; }
const std::string &getDescription() const { return Description; }
bool isInitialized() const { return TG != nullptr; }
/// Check if the timer is currently running.
bool isRunning() const { return Running; }
/// Check if startTimer() has ever been called on this timer.
bool hasTriggered() const { return Triggered; }
/// Start the timer running. Time between calls to startTimer/stopTimer is
/// counted by the Timer class. Note that these calls must be correctly
/// paired.
void startTimer();
/// Stop the timer.
void stopTimer();
/// Clear the timer state.
void clear();
/// Return the duration for which this timer has been running.
TimeRecord getTotalTime() const { return Time; }
friend class TimerGroup;
/// The TimeRegion class is used as a helper class to call the startTimer() and
/// stopTimer() methods of the Timer class. When the object is constructed, it
/// starts the timer specified as its argument. When it is destroyed, it stops
/// the relevant timer. This makes it easy to time a region of code.
class TimeRegion {
Timer *T;
TimeRegion(const TimeRegion &) = delete;
explicit TimeRegion(Timer &t) : T(&t) {
explicit TimeRegion(Timer *t) : T(t) {
if (T) T->startTimer();
~TimeRegion() {
if (T) T->stopTimer();
/// This class is basically a combination of TimeRegion and Timer. It allows
/// you to declare a new timer, AND specify the region to time, all in one
/// statement. All timers with the same name are merged. This is primarily
/// used for debugging and for hunting performance problems.
struct NamedRegionTimer : public TimeRegion {
explicit NamedRegionTimer(StringRef Name, StringRef Description,
StringRef GroupName,
StringRef GroupDescription, bool Enabled = true);
/// The TimerGroup class is used to group together related timers into a single
/// report that is printed when the TimerGroup is destroyed. It is illegal to
/// destroy a TimerGroup object before all of the Timers in it are gone. A
/// TimerGroup can be specified for a newly created timer in its constructor.
class TimerGroup {
struct PrintRecord {
TimeRecord Time;
std::string Name;
std::string Description;
PrintRecord(const PrintRecord &Other) = default;
PrintRecord(const TimeRecord &Time, const std::string &Name,
const std::string &Description)
: Time(Time), Name(Name), Description(Description) {}
bool operator <(const PrintRecord &Other) const {
return Time < Other.Time;
std::string Name;
std::string Description;
Timer *FirstTimer = nullptr; ///< First timer in the group.
std::vector<PrintRecord> TimersToPrint;
TimerGroup **Prev; ///< Pointer to Next field of previous timergroup in list.
TimerGroup *Next; ///< Pointer to next timergroup in list.
TimerGroup(const TimerGroup &TG) = delete;
void operator=(const TimerGroup &TG) = delete;
explicit TimerGroup(StringRef Name, StringRef Description);
explicit TimerGroup(StringRef Name, StringRef Description,
const StringMap<TimeRecord> &Records);
void setName(StringRef NewName, StringRef NewDescription) {
Name.assign(NewName.begin(), NewName.end());
Description.assign(NewDescription.begin(), NewDescription.end());
/// Print any started timers in this group, optionally resetting timers after
/// printing them.
void print(raw_ostream &OS, bool ResetAfterPrint = false);
/// Clear all timers in this group.
void clear();
/// This static method prints all timers.
static void printAll(raw_ostream &OS);
/// Clear out all timers. This is mostly used to disable automatic
/// printing on shutdown, when timers have already been printed explicitly
/// using \c printAll or \c printJSONValues.
static void clearAll();
const char *printJSONValues(raw_ostream &OS, const char *delim);
/// Prints all timers as JSON key/value pairs.
static const char *printAllJSONValues(raw_ostream &OS, const char *delim);
/// Ensure global timer group lists are initialized. This function is mostly
/// used by the Statistic code to influence the construction and destruction
/// order of the global timer lists.
static void ConstructTimerLists();
friend class Timer;
friend void PrintStatisticsJSON(raw_ostream &OS);
void addTimer(Timer &T);
void removeTimer(Timer &T);
void prepareToPrintList(bool reset_time = false);
void PrintQueuedTimers(raw_ostream &OS);
void printJSONValue(raw_ostream &OS, const PrintRecord &R,
const char *suffix, double Value);
} // end namespace llvm