MacroAssemblerCodePtr StructureStubInfo::addAccessCase(
CodeBlock* codeBlock, const Identifier& ident, std::unique_ptr<AccessCase> accessCase)
{
VM& vm = *codeBlock->vm();
if (!accessCase)
return MacroAssemblerCodePtr();
if (cacheType == CacheType::Stub)
return u.stub->regenerateWithCase(vm, codeBlock, *this, ident, WTFMove(accessCase));
std::unique_ptr<PolymorphicAccess> access = std::make_unique<PolymorphicAccess>();
Vector<std::unique_ptr<AccessCase>> accessCases;
std::unique_ptr<AccessCase> previousCase =
AccessCase::fromStructureStubInfo(vm, codeBlock, *this);
if (previousCase)
accessCases.append(WTFMove(previousCase));
accessCases.append(WTFMove(accessCase));
MacroAssemblerCodePtr result =
access->regenerateWithCases(vm, codeBlock, *this, ident, WTFMove(accessCases));
if (!result)
return MacroAssemblerCodePtr();
initStub(codeBlock, WTFMove(access));
return result;
}
AccessGenerationResult StructureStubInfo::addAccessCase(
CodeBlock* codeBlock, const Identifier& ident, std::unique_ptr<AccessCase> accessCase)
{
VM& vm = *codeBlock->vm();
if (verbose)
dataLog("Adding access case: ", accessCase, "\n");
if (!accessCase)
return AccessGenerationResult::GaveUp;
AccessGenerationResult result;
if (cacheType == CacheType::Stub) {
result = u.stub->addCase(vm, codeBlock, *this, ident, WTFMove(accessCase));
if (verbose)
dataLog("Had stub, result: ", result, "\n");
if (!result.buffered()) {
bufferedStructures.clear();
return result;
}
} else {
std::unique_ptr<PolymorphicAccess> access = std::make_unique<PolymorphicAccess>();
Vector<std::unique_ptr<AccessCase>, 2> accessCases;
std::unique_ptr<AccessCase> previousCase =
AccessCase::fromStructureStubInfo(vm, codeBlock, *this);
if (previousCase)
accessCases.append(WTFMove(previousCase));
accessCases.append(WTFMove(accessCase));
result = access->addCases(vm, codeBlock, *this, ident, WTFMove(accessCases));
if (verbose)
dataLog("Created stub, result: ", result, "\n");
if (!result.buffered()) {
bufferedStructures.clear();
return result;
}
initStub(codeBlock, WTFMove(access));
}
RELEASE_ASSERT(!result.generatedSomeCode());
// If we didn't buffer any cases then bail. If this made no changes then we'll just try again
// subject to cool-down.
if (!result.buffered()) {
if (verbose)
dataLog("Didn't buffer anything, bailing.\n");
bufferedStructures.clear();
return result;
}
// The buffering countdown tells us if we should be repatching now.
if (bufferingCountdown) {
if (verbose)
dataLog("Countdown is too high: ", bufferingCountdown, ".\n");
return result;
}
// Forget the buffered structures so that all future attempts to cache get fully handled by the
// PolymorphicAccess.
bufferedStructures.clear();
result = u.stub->regenerate(vm, codeBlock, *this, ident);
if (verbose)
dataLog("Regeneration result: ", result, "\n");
RELEASE_ASSERT(!result.buffered());
if (!result.generatedSomeCode())
return result;
// If we generated some code then we don't want to attempt to repatch in the future until we
// gather enough cases.
bufferingCountdown = Options::repatchBufferingCountdown();
return result;
}