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/*
* Copyright (C) 2013-2022 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 "FTLOSREntry.h"
#include "CallFrame.h"
#include "CodeBlock.h"
#include "DFGJITCode.h"
#include "FTLForOSREntryJITCode.h"
#include "JSCJSValueInlines.h"
#include "OperandsInlines.h"
#include "VMInlines.h"
#if ENABLE(FTL_JIT)
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
namespace JSC { namespace FTL {
SUPPRESS_ASAN
void* prepareOSREntry(
VM& vm, CallFrame* callFrame, CodeBlock* dfgCodeBlock, CodeBlock* entryCodeBlock,
BytecodeIndex bytecodeIndex, unsigned streamIndex)
{
CodeBlock* baseline = dfgCodeBlock->baselineVersion();
ExecutableBase* executable = dfgCodeBlock->ownerExecutable();
DFG::JITCode* dfgCode = dfgCodeBlock->jitCode()->dfg();
ForOSREntryJITCode* entryCode = entryCodeBlock->jitCode()->ftlForOSREntry();
if (!entryCode->dfgCommon()->isStillValid()) {
dfgCode->clearOSREntryBlockAndResetThresholds(dfgCodeBlock);
return nullptr;
}
dataLogLnIf(Options::verboseOSR(),
"FTL OSR from ", *dfgCodeBlock, " to ", *entryCodeBlock, " at ",
bytecodeIndex);
if (bytecodeIndex)
jsCast<ScriptExecutable*>(executable)->setDidTryToEnterInLoop(true);
if (bytecodeIndex != entryCode->bytecodeIndex()) {
dataLogLnIf(Options::verboseOSR(), " OSR failed because we don't have an entrypoint for ", bytecodeIndex, "; ours is for ", entryCode->bytecodeIndex());
return nullptr;
}
Operands<std::optional<JSValue>> values;
dfgCode->reconstruct(callFrame, dfgCodeBlock, CodeOrigin(bytecodeIndex), streamIndex, values);
dataLogLnIf(Options::verboseOSR(), " Values at entry: ", values);
std::optional<JSValue> reconstructedThis;
for (int argument = values.numberOfArguments(); argument--;) {
JSValue valueOnStack = callFrame->r(virtualRegisterForArgumentIncludingThis(argument)).asanUnsafeJSValue();
std::optional<JSValue> reconstructedValue = values.argument(argument);
{
JSValue valueToValidate = reconstructedValue ? *reconstructedValue : valueOnStack;
auto flushFormat = entryCode->argumentFlushFormats()[argument];
switch (flushFormat) {
case DFG::FlushedInt32:
if (!valueToValidate.isInt32())
return nullptr;
break;
case DFG::FlushedBoolean:
if (!valueToValidate.isBoolean())
return nullptr;
break;
case DFG::FlushedCell:
if (!valueToValidate.isCell())
return nullptr;
break;
case DFG::FlushedJSValue:
break;
default:
dataLogLn("Unknown flush format for argument during FTL osr entry: ", flushFormat);
RELEASE_ASSERT_NOT_REACHED();
break;
}
}
if (!argument) {
// |this| argument can be unboxed. We should store boxed value instead for loop OSR entry since FTL assumes that all arguments are flushed JSValue.
// To make this valid, we will modify the stack on the fly: replacing the value with boxed value.
reconstructedThis = reconstructedValue;
continue;
}
if (reconstructedValue && valueOnStack == reconstructedValue.value())
continue;
dataLogLn(
"Mismatch between reconstructed values and the value on the stack for argument arg", argument, " for ", *entryCodeBlock, " at ", bytecodeIndex, ":\n",
" Value on stack: ", valueOnStack, "\n",
" Reconstructed value: ", reconstructedValue);
RELEASE_ASSERT_NOT_REACHED();
}
RELEASE_ASSERT(values.numberOfLocals() == baseline->numCalleeLocals());
EncodedJSValue* scratch = static_cast<EncodedJSValue*>(
entryCode->entryBuffer()->dataBuffer());
for (int local = values.numberOfLocals(); local--;) {
std::optional<JSValue> value = values.local(local);
if (value)
scratch[local] = JSValue::encode(value.value());
else
scratch[local] = JSValue::encode(JSValue());
}
int stackFrameSize = entryCode->common.requiredRegisterCountForExecutionAndExit();
if (UNLIKELY(!vm.ensureStackCapacityFor(&callFrame->registers()[virtualRegisterForLocal(stackFrameSize - 1).offset()]))) {
dataLogLnIf(Options::verboseOSR(), " OSR failed because stack growth failed.");
return nullptr;
}
callFrame->setCodeBlock(entryCodeBlock);
void* result = entryCode->addressForCall(ArityCheckNotRequired).taggedPtr();
dataLogLnIf(Options::verboseOSR(), " Entry will succeed, going to address ", RawPointer(result));
// At this point, we're committed to triggering an OSR entry immediately after we return. Hence, it is safe to modify stack here.
if (result) {
if (reconstructedThis)
callFrame->r(virtualRegisterForArgumentIncludingThis(0)) = JSValue::encode(reconstructedThis.value());
}
return result;
}
} } // namespace JSC::FTL
WTF_ALLOW_UNSAFE_BUFFER_USAGE_END
#endif // ENABLE(FTL_JIT)
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