llvm/llvm/include/llvm/Support/Timer.h

//===-- llvm/Support/Timer.h - Interval Timing Support ----------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_SUPPORT_TIMER_H
#define LLVM_SUPPORT_TIMER_H

#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/DataTypes.h"
#include <cassert>
#include <memory>
#include <string>
#include <vector>

namespace llvm {

class TimerGroup;
class raw_ostream;

class TimeRecord { … };

/// 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 { … };

/// 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 { … };

/// 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 { … };

/// 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 { … };

} // end namespace llvm

#endif