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/*
* Copyright (C) 2012 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.
*/
#include "config.h"
#include "PutByIdStatus.h"
#include "CodeBlock.h"
#include "LLIntData.h"
#include "LowLevelInterpreter.h"
#include "Operations.h"
#include "Structure.h"
#include "StructureChain.h"
namespace JSC {
PutByIdStatus PutByIdStatus::computeFromLLInt(CodeBlock* profiledBlock, unsigned bytecodeIndex, Identifier& ident)
{
UNUSED_PARAM(profiledBlock);
UNUSED_PARAM(bytecodeIndex);
UNUSED_PARAM(ident);
#if ENABLE(LLINT)
Instruction* instruction = profiledBlock->instructions().begin() + bytecodeIndex;
Structure* structure = instruction[4].u.structure.get();
if (!structure)
return PutByIdStatus(NoInformation, 0, 0, 0, invalidOffset);
if (instruction[0].u.opcode == LLInt::getOpcode(llint_op_put_by_id)
|| instruction[0].u.opcode == LLInt::getOpcode(llint_op_put_by_id_out_of_line)) {
PropertyOffset offset = structure->get(*profiledBlock->vm(), ident);
if (!isValidOffset(offset))
return PutByIdStatus(NoInformation, 0, 0, 0, invalidOffset);
return PutByIdStatus(SimpleReplace, structure, 0, 0, offset);
}
ASSERT(structure->transitionWatchpointSetHasBeenInvalidated());
ASSERT(instruction[0].u.opcode == LLInt::getOpcode(llint_op_put_by_id_transition_direct)
|| instruction[0].u.opcode == LLInt::getOpcode(llint_op_put_by_id_transition_normal)
|| instruction[0].u.opcode == LLInt::getOpcode(llint_op_put_by_id_transition_direct_out_of_line)
|| instruction[0].u.opcode == LLInt::getOpcode(llint_op_put_by_id_transition_normal_out_of_line));
Structure* newStructure = instruction[6].u.structure.get();
StructureChain* chain = instruction[7].u.structureChain.get();
ASSERT(newStructure);
ASSERT(chain);
PropertyOffset offset = newStructure->get(*profiledBlock->vm(), ident);
if (!isValidOffset(offset))
return PutByIdStatus(NoInformation, 0, 0, 0, invalidOffset);
return PutByIdStatus(SimpleTransition, structure, newStructure, chain, offset);
#else
return PutByIdStatus(NoInformation, 0, 0, 0, invalidOffset);
#endif
}
PutByIdStatus PutByIdStatus::computeFor(CodeBlock* profiledBlock, unsigned bytecodeIndex, Identifier& ident)
{
UNUSED_PARAM(profiledBlock);
UNUSED_PARAM(bytecodeIndex);
UNUSED_PARAM(ident);
#if ENABLE(JIT) && ENABLE(VALUE_PROFILER)
if (!profiledBlock->numberOfStructureStubInfos())
return computeFromLLInt(profiledBlock, bytecodeIndex, ident);
if (profiledBlock->likelyToTakeSlowCase(bytecodeIndex))
return PutByIdStatus(TakesSlowPath, 0, 0, 0, invalidOffset);
StructureStubInfo& stubInfo = profiledBlock->getStubInfo(bytecodeIndex);
if (!stubInfo.seen)
return computeFromLLInt(profiledBlock, bytecodeIndex, ident);
if (stubInfo.resetByGC)
return PutByIdStatus(TakesSlowPath, 0, 0, 0, invalidOffset);
switch (stubInfo.accessType) {
case access_unset:
// If the JIT saw it but didn't optimize it, then assume that this takes slow path.
return PutByIdStatus(TakesSlowPath, 0, 0, 0, invalidOffset);
case access_put_by_id_replace: {
PropertyOffset offset = stubInfo.u.putByIdReplace.baseObjectStructure->get(
*profiledBlock->vm(), ident);
if (isValidOffset(offset)) {
return PutByIdStatus(
SimpleReplace,
stubInfo.u.putByIdReplace.baseObjectStructure.get(),
0, 0,
offset);
}
return PutByIdStatus(TakesSlowPath, 0, 0, 0, invalidOffset);
}
case access_put_by_id_transition_normal:
case access_put_by_id_transition_direct: {
ASSERT(stubInfo.u.putByIdTransition.previousStructure->transitionWatchpointSetHasBeenInvalidated());
PropertyOffset offset = stubInfo.u.putByIdTransition.structure->get(
*profiledBlock->vm(), ident);
if (isValidOffset(offset)) {
return PutByIdStatus(
SimpleTransition,
stubInfo.u.putByIdTransition.previousStructure.get(),
stubInfo.u.putByIdTransition.structure.get(),
stubInfo.u.putByIdTransition.chain.get(),
offset);
}
return PutByIdStatus(TakesSlowPath, 0, 0, 0, invalidOffset);
}
default:
return PutByIdStatus(TakesSlowPath, 0, 0, 0, invalidOffset);
}
#else // ENABLE(JIT)
return PutByIdStatus(NoInformation, 0, 0, 0, invalidOffset);
#endif // ENABLE(JIT)
}
PutByIdStatus PutByIdStatus::computeFor(VM& vm, JSGlobalObject* globalObject, Structure* structure, Identifier& ident, bool isDirect)
{
if (PropertyName(ident).asIndex() != PropertyName::NotAnIndex)
return PutByIdStatus(TakesSlowPath);
if (structure->typeInfo().overridesGetOwnPropertySlot())
return PutByIdStatus(TakesSlowPath);
if (!structure->propertyAccessesAreCacheable())
return PutByIdStatus(TakesSlowPath);
unsigned attributes;
JSCell* specificValue;
PropertyOffset offset = structure->get(vm, ident, attributes, specificValue);
if (isValidOffset(offset)) {
if (attributes & (Accessor | ReadOnly))
return PutByIdStatus(TakesSlowPath);
if (specificValue) {
// We need the PutById slow path to verify that we're storing the right value into
// the specialized slot.
return PutByIdStatus(TakesSlowPath);
}
return PutByIdStatus(SimpleReplace, structure, 0, 0, offset);
}
// Our hypothesis is that we're doing a transition. Before we prove that this is really
// true, we want to do some sanity checks.
// Don't cache put transitions on dictionaries.
if (structure->isDictionary())
return PutByIdStatus(TakesSlowPath);
// If the structure corresponds to something that isn't an object, then give up, since
// we don't want to be adding properties to strings.
if (structure->typeInfo().type() == StringType)
return PutByIdStatus(TakesSlowPath);
if (!isDirect) {
// If the prototype chain has setters or read-only properties, then give up.
if (structure->prototypeChainMayInterceptStoreTo(vm, ident))
return PutByIdStatus(TakesSlowPath);
// If the prototype chain hasn't been normalized (i.e. there are proxies or dictionaries)
// then give up. The dictionary case would only happen if this structure has not been
// used in an optimized put_by_id transition. And really the only reason why we would
// bail here is that I don't really feel like having the optimizing JIT go and flatten
// dictionaries if we have evidence to suggest that those objects were never used as
// prototypes in a cacheable prototype access - i.e. there's a good chance that some of
// the other checks below will fail.
if (!isPrototypeChainNormalized(globalObject, structure))
return PutByIdStatus(TakesSlowPath);
}
// We only optimize if there is already a structure that the transition is cached to.
// Among other things, this allows us to guard against a transition with a specific
// value.
//
// - If we're storing a value that could be specific: this would only be a problem if
// the existing transition did have a specific value already, since if it didn't,
// then we would behave "as if" we were not storing a specific value. If it did
// have a specific value, then we'll know - the fact that we pass 0 for
// specificValue will tell us.
//
// - If we're not storing a value that could be specific: again, this would only be a
// problem if the existing transition did have a specific value, which we check for
// by passing 0 for the specificValue.
Structure* transition = Structure::addPropertyTransitionToExistingStructure(structure, ident, 0, 0, offset);
if (!transition)
return PutByIdStatus(TakesSlowPath); // This occurs in bizarre cases only. See above.
ASSERT(!transition->transitionDidInvolveSpecificValue());
ASSERT(isValidOffset(offset));
return PutByIdStatus(
SimpleTransition, structure, transition,
structure->prototypeChain(vm, globalObject), offset);
}
} // namespace JSC
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