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212 lines (180 loc) · 6.86 KB
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/*
* Copyright (C) 2011, 2012, 2013 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.
* 3. Neither the name of Apple Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "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 OR ITS 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.
*/
#ifndef ValueProfile_h
#define ValueProfile_h
#include "ConcurrentJITLock.h"
#include "Heap.h"
#include "JSArray.h"
#include "SpeculatedType.h"
#include "Structure.h"
#include "WriteBarrier.h"
#include <wtf/PrintStream.h>
#include <wtf/StringPrintStream.h>
namespace JSC {
template<unsigned numberOfBucketsArgument>
struct ValueProfileBase {
static const unsigned numberOfBuckets = numberOfBucketsArgument;
static const unsigned numberOfSpecFailBuckets = 1;
static const unsigned bucketIndexMask = numberOfBuckets - 1;
static const unsigned totalNumberOfBuckets = numberOfBuckets + numberOfSpecFailBuckets;
ValueProfileBase()
: m_bytecodeOffset(-1)
, m_prediction(SpecNone)
, m_numberOfSamplesInPrediction(0)
{
for (unsigned i = 0; i < totalNumberOfBuckets; ++i)
m_buckets[i] = JSValue::encode(JSValue());
}
ValueProfileBase(int bytecodeOffset)
: m_bytecodeOffset(bytecodeOffset)
, m_prediction(SpecNone)
, m_numberOfSamplesInPrediction(0)
{
for (unsigned i = 0; i < totalNumberOfBuckets; ++i)
m_buckets[i] = JSValue::encode(JSValue());
}
EncodedJSValue* specFailBucket(unsigned i)
{
ASSERT(numberOfBuckets + i < totalNumberOfBuckets);
return m_buckets + numberOfBuckets + i;
}
const ClassInfo* classInfo(unsigned bucket) const
{
JSValue value = JSValue::decode(m_buckets[bucket]);
if (!!value) {
if (!value.isCell())
return 0;
return value.asCell()->structure()->classInfo();
}
return 0;
}
unsigned numberOfSamples() const
{
unsigned result = 0;
for (unsigned i = 0; i < totalNumberOfBuckets; ++i) {
if (!!JSValue::decode(m_buckets[i]))
result++;
}
return result;
}
unsigned totalNumberOfSamples() const
{
return numberOfSamples() + m_numberOfSamplesInPrediction;
}
bool isLive() const
{
for (unsigned i = 0; i < totalNumberOfBuckets; ++i) {
if (!!JSValue::decode(m_buckets[i]))
return true;
}
return false;
}
CString briefDescription(const ConcurrentJITLocker& locker)
{
computeUpdatedPrediction(locker);
StringPrintStream out;
out.print("predicting ", SpeculationDump(m_prediction));
return out.toCString();
}
void dump(PrintStream& out)
{
out.print("samples = ", totalNumberOfSamples(), " prediction = ", SpeculationDump(m_prediction));
bool first = true;
for (unsigned i = 0; i < totalNumberOfBuckets; ++i) {
JSValue value = JSValue::decode(m_buckets[i]);
if (!!value) {
if (first) {
out.printf(": ");
first = false;
} else
out.printf(", ");
out.print(value);
}
}
}
// Updates the prediction and returns the new one. Never call this from any thread
// that isn't executing the code.
SpeculatedType computeUpdatedPrediction(const ConcurrentJITLocker&)
{
for (unsigned i = 0; i < totalNumberOfBuckets; ++i) {
JSValue value = JSValue::decode(m_buckets[i]);
if (!value)
continue;
m_numberOfSamplesInPrediction++;
mergeSpeculation(m_prediction, speculationFromValue(value));
m_buckets[i] = JSValue::encode(JSValue());
}
return m_prediction;
}
int m_bytecodeOffset; // -1 for prologue
SpeculatedType m_prediction;
unsigned m_numberOfSamplesInPrediction;
EncodedJSValue m_buckets[totalNumberOfBuckets];
};
struct MinimalValueProfile : public ValueProfileBase<0> {
MinimalValueProfile(): ValueProfileBase<0>() { }
MinimalValueProfile(int bytecodeOffset): ValueProfileBase<0>(bytecodeOffset) { }
};
template<unsigned logNumberOfBucketsArgument>
struct ValueProfileWithLogNumberOfBuckets : public ValueProfileBase<1 << logNumberOfBucketsArgument> {
static const unsigned logNumberOfBuckets = logNumberOfBucketsArgument;
ValueProfileWithLogNumberOfBuckets()
: ValueProfileBase<1 << logNumberOfBucketsArgument>()
{
}
ValueProfileWithLogNumberOfBuckets(int bytecodeOffset)
: ValueProfileBase<1 << logNumberOfBucketsArgument>(bytecodeOffset)
{
}
};
struct ValueProfile : public ValueProfileWithLogNumberOfBuckets<0> {
ValueProfile(): ValueProfileWithLogNumberOfBuckets<0>() { }
ValueProfile(int bytecodeOffset): ValueProfileWithLogNumberOfBuckets<0>(bytecodeOffset) { }
};
template<typename T>
inline int getValueProfileBytecodeOffset(T* valueProfile)
{
return valueProfile->m_bytecodeOffset;
}
// This is a mini value profile to catch pathologies. It is a counter that gets
// incremented when we take the slow path on any instruction.
struct RareCaseProfile {
RareCaseProfile(int bytecodeOffset)
: m_bytecodeOffset(bytecodeOffset)
, m_counter(0)
{
}
int m_bytecodeOffset;
uint32_t m_counter;
};
inline int getRareCaseProfileBytecodeOffset(RareCaseProfile* rareCaseProfile)
{
return rareCaseProfile->m_bytecodeOffset;
}
} // namespace JSC
#endif // ValueProfile_h