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/*
* Copyright (C) 2012-2017 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include "Options.h"
#include <wtf/Nonmovable.h>
#include <wtf/PrintStream.h>
namespace JSC {
class CodeBlock;
enum CountingVariant {
CountingForBaseline,
CountingForUpperTiers
};
double applyMemoryUsageHeuristics(int32_t value, CodeBlock*);
int32_t applyMemoryUsageHeuristicsAndConvertToInt(int32_t value, CodeBlock*);
inline int32_t formattedTotalExecutionCount(float value)
{
union {
int32_t i;
float f;
} u;
u.f = value;
return u.i;
}
template<CountingVariant countingVariant>
class ExecutionCounter {
WTF_MAKE_FAST_ALLOCATED;
WTF_MAKE_NONMOVABLE(ExecutionCounter);
public:
ExecutionCounter();
void forceSlowPathConcurrently(); // If you use this, checkIfThresholdCrossedAndSet() may still return false.
bool checkIfThresholdCrossedAndSet(CodeBlock*);
bool hasCrossedThreshold() const { return m_counter >= 0; }
void setNewThreshold(int32_t threshold, CodeBlock* = nullptr);
void deferIndefinitely();
double count() const { return static_cast<double>(m_totalCount) + m_counter; }
void dump(PrintStream&) const;
void setNewThresholdForOSRExit(uint32_t activeThreshold, double memoryUsageAdjustedThreshold)
{
m_activeThreshold = activeThreshold;
m_counter = static_cast<int32_t>(-memoryUsageAdjustedThreshold);
m_totalCount = memoryUsageAdjustedThreshold;
}
static int32_t maximumExecutionCountsBetweenCheckpoints()
{
switch (countingVariant) {
case CountingForBaseline:
return Options::maximumExecutionCountsBetweenCheckpointsForBaseline();
case CountingForUpperTiers:
return Options::maximumExecutionCountsBetweenCheckpointsForUpperTiers();
default:
RELEASE_ASSERT_NOT_REACHED();
return 0;
}
}
template<typename T>
static T clippedThreshold(T threshold)
{
int32_t maxThreshold = maximumExecutionCountsBetweenCheckpoints();
if (threshold > maxThreshold)
threshold = maxThreshold;
return threshold;
}
private:
bool hasCrossedThreshold(CodeBlock*) const;
bool setThreshold(CodeBlock*);
void reset();
public:
// NB. These are intentionally public because it will be modified from machine code.
// This counter is incremented by the JIT or LLInt. It starts out negative and is
// counted up until it becomes non-negative. At the start of a counting period,
// the threshold we wish to reach is m_totalCount + m_counter, in the sense that
// we will add X to m_totalCount and subtract X from m_counter.
int32_t m_counter;
// Counts the total number of executions we have seen plus the ones we've set a
// threshold for in m_counter. Because m_counter's threshold is negative, the
// total number of actual executions can always be computed as m_totalCount +
// m_counter.
float m_totalCount;
// This is the threshold we were originally targeting, without any correction for
// the memory usage heuristics.
int32_t m_activeThreshold;
};
typedef ExecutionCounter<CountingForBaseline> BaselineExecutionCounter;
typedef ExecutionCounter<CountingForUpperTiers> UpperTierExecutionCounter;
} // namespace JSC
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