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darling-JavaScriptCore/dfg/DFGJITCompiler.cpp

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/*
* Copyright (C) 2011-2019 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 "DFGJITCompiler.h"
#if ENABLE(DFG_JIT)
#include "CodeBlock.h"
#include "DFGFailedFinalizer.h"
#include "DFGInlineCacheWrapperInlines.h"
#include "DFGJITCode.h"
#include "DFGJITFinalizer.h"
#include "DFGOSRExit.h"
#include "DFGSpeculativeJIT.h"
#include "DFGThunks.h"
#include "JSCJSValueInlines.h"
#include "LinkBuffer.h"
#include "MaxFrameExtentForSlowPathCall.h"
#include "ThunkGenerators.h"
#include "VM.h"
namespace JSC { namespace DFG {
JITCompiler::JITCompiler(Graph& dfg)
: CCallHelpers(dfg.m_codeBlock)
, m_graph(dfg)
, m_jitCode(adoptRef(new JITCode()))
, m_blockHeads(dfg.numBlocks())
, m_pcToCodeOriginMapBuilder(dfg.m_vm)
{
if (UNLIKELY(shouldDumpDisassembly() || m_graph.m_vm.m_perBytecodeProfiler))
m_disassembler = makeUnique<Disassembler>(dfg);
#if ENABLE(FTL_JIT)
m_jitCode->tierUpInLoopHierarchy = WTFMove(m_graph.m_plan.tierUpInLoopHierarchy());
for (BytecodeIndex tierUpBytecode : m_graph.m_plan.tierUpAndOSREnterBytecodes())
m_jitCode->tierUpEntryTriggers.add(tierUpBytecode, JITCode::TriggerReason::DontTrigger);
#endif
}
JITCompiler::~JITCompiler()
{
}
void JITCompiler::linkOSRExits()
{
ASSERT(m_jitCode->osrExit.size() == m_exitCompilationInfo.size());
if (UNLIKELY(m_graph.compilation())) {
for (unsigned i = 0; i < m_jitCode->osrExit.size(); ++i) {
OSRExitCompilationInfo& info = m_exitCompilationInfo[i];
Vector<Label> labels;
if (!info.m_failureJumps.empty()) {
for (unsigned j = 0; j < info.m_failureJumps.jumps().size(); ++j)
labels.append(info.m_failureJumps.jumps()[j].label());
} else
labels.append(info.m_replacementSource);
m_exitSiteLabels.append(labels);
}
}
for (unsigned i = 0; i < m_jitCode->osrExit.size(); ++i) {
OSRExitCompilationInfo& info = m_exitCompilationInfo[i];
JumpList& failureJumps = info.m_failureJumps;
if (!failureJumps.empty())
failureJumps.link(this);
else
info.m_replacementDestination = label();
jitAssertHasValidCallFrame();
store32(TrustedImm32(i), &vm().osrExitIndex);
info.m_patchableJump = patchableJump();
}
}
void JITCompiler::compileEntry()
{
// This code currently matches the old JIT. In the function header we need to
// save return address and call frame via the prologue and perform a fast stack check.
// FIXME: https://bugs.webkit.org/show_bug.cgi?id=56292
// We'll need to convert the remaining cti_ style calls (specifically the stack
// check) which will be dependent on stack layout. (We'd need to account for this in
// both normal return code and when jumping to an exception handler).
emitFunctionPrologue();
emitPutToCallFrameHeader(m_codeBlock, CallFrameSlot::codeBlock);
}
void JITCompiler::compileSetupRegistersForEntry()
{
emitSaveCalleeSaves();
emitMaterializeTagCheckRegisters();
}
void JITCompiler::compileEntryExecutionFlag()
{
#if ENABLE(FTL_JIT)
if (m_graph.m_plan.canTierUpAndOSREnter())
store8(TrustedImm32(0), &m_jitCode->neverExecutedEntry);
#endif // ENABLE(FTL_JIT)
}
void JITCompiler::compileBody()
{
// We generate the speculative code path, followed by OSR exit code to return
// to the old JIT code if speculations fail.
bool compiledSpeculative = m_speculative->compile();
ASSERT_UNUSED(compiledSpeculative, compiledSpeculative);
}
void JITCompiler::compileExceptionHandlers()
{
if (!m_exceptionChecksWithCallFrameRollback.empty()) {
m_exceptionChecksWithCallFrameRollback.link(this);
copyCalleeSavesToEntryFrameCalleeSavesBuffer(vm().topEntryFrame);
// operationLookupExceptionHandlerFromCallerFrame is passed one argument, the VM*.
move(TrustedImmPtr(&vm()), GPRInfo::argumentGPR0);
prepareCallOperation(vm());
addPtr(TrustedImm32(m_graph.stackPointerOffset() * sizeof(Register)), GPRInfo::callFrameRegister, stackPointerRegister);
appendCall(operationLookupExceptionHandlerFromCallerFrame);
jumpToExceptionHandler(vm());
}
if (!m_exceptionChecks.empty()) {
m_exceptionChecks.link(this);
copyCalleeSavesToEntryFrameCalleeSavesBuffer(vm().topEntryFrame);
// operationLookupExceptionHandler is passed one argument, the VM*.
move(TrustedImmPtr(&vm()), GPRInfo::argumentGPR0);
prepareCallOperation(vm());
appendCall(operationLookupExceptionHandler);
jumpToExceptionHandler(vm());
}
}
void JITCompiler::link(LinkBuffer& linkBuffer)
{
// Link the code, populate data in CodeBlock data structures.
m_jitCode->common.frameRegisterCount = m_graph.frameRegisterCount();
m_jitCode->common.requiredRegisterCountForExit = m_graph.requiredRegisterCountForExit();
if (!m_graph.m_plan.inlineCallFrames()->isEmpty())
m_jitCode->common.inlineCallFrames = m_graph.m_plan.inlineCallFrames();
#if USE(JSVALUE32_64)
m_jitCode->common.doubleConstants = WTFMove(m_graph.m_doubleConstants);
#endif
m_graph.registerFrozenValues();
BitVector usedJumpTables;
for (Bag<SwitchData>::iterator iter = m_graph.m_switchData.begin(); !!iter; ++iter) {
SwitchData& data = **iter;
if (!data.didUseJumpTable)
continue;
if (data.kind == SwitchString)
continue;
RELEASE_ASSERT(data.kind == SwitchImm || data.kind == SwitchChar);
usedJumpTables.set(data.switchTableIndex);
SimpleJumpTable& table = m_codeBlock->switchJumpTable(data.switchTableIndex);
table.ctiDefault = linkBuffer.locationOf<JSSwitchPtrTag>(m_blockHeads[data.fallThrough.block->index]);
table.ctiOffsets.grow(table.branchOffsets.size());
for (unsigned j = table.ctiOffsets.size(); j--;)
table.ctiOffsets[j] = table.ctiDefault;
for (unsigned j = data.cases.size(); j--;) {
SwitchCase& myCase = data.cases[j];
table.ctiOffsets[myCase.value.switchLookupValue(data.kind) - table.min] =
linkBuffer.locationOf<JSSwitchPtrTag>(m_blockHeads[myCase.target.block->index]);
}
}
for (unsigned i = m_codeBlock->numberOfSwitchJumpTables(); i--;) {
if (usedJumpTables.get(i))
continue;
m_codeBlock->switchJumpTable(i).clear();
}
// NOTE: we cannot clear string switch tables because (1) we're running concurrently
// and we cannot deref StringImpl's and (2) it would be weird to deref those
// StringImpl's since we refer to them.
for (Bag<SwitchData>::iterator switchDataIter = m_graph.m_switchData.begin(); !!switchDataIter; ++switchDataIter) {
SwitchData& data = **switchDataIter;
if (!data.didUseJumpTable)
continue;
if (data.kind != SwitchString)
continue;
StringJumpTable& table = m_codeBlock->stringSwitchJumpTable(data.switchTableIndex);
table.ctiDefault = linkBuffer.locationOf<JSSwitchPtrTag>(m_blockHeads[data.fallThrough.block->index]);
StringJumpTable::StringOffsetTable::iterator iter;
StringJumpTable::StringOffsetTable::iterator end = table.offsetTable.end();
for (iter = table.offsetTable.begin(); iter != end; ++iter)
iter->value.ctiOffset = table.ctiDefault;
for (unsigned j = data.cases.size(); j--;) {
SwitchCase& myCase = data.cases[j];
iter = table.offsetTable.find(myCase.value.stringImpl());
RELEASE_ASSERT(iter != end);
iter->value.ctiOffset = linkBuffer.locationOf<JSSwitchPtrTag>(m_blockHeads[myCase.target.block->index]);
}
}
// Link all calls out from the JIT code to their respective functions.
for (unsigned i = 0; i < m_calls.size(); ++i)
linkBuffer.link(m_calls[i].m_call, m_calls[i].m_function);
finalizeInlineCaches(m_getByIds, linkBuffer);
finalizeInlineCaches(m_getByIdsWithThis, linkBuffer);
finalizeInlineCaches(m_getByVals, linkBuffer);
finalizeInlineCaches(m_putByIds, linkBuffer);
finalizeInlineCaches(m_delByIds, linkBuffer);
finalizeInlineCaches(m_delByVals, linkBuffer);
finalizeInlineCaches(m_inByIds, linkBuffer);
finalizeInlineCaches(m_instanceOfs, linkBuffer);
auto linkCallThunk = FunctionPtr<NoPtrTag>(vm().getCTIStub(linkCallThunkGenerator).retaggedCode<NoPtrTag>());
for (auto& record : m_jsCalls) {
CallLinkInfo& info = *record.info;
linkBuffer.link(record.slowCall, linkCallThunk);
info.setCallLocations(
CodeLocationLabel<JSInternalPtrTag>(linkBuffer.locationOfNearCall<JSInternalPtrTag>(record.slowCall)),
CodeLocationLabel<JSInternalPtrTag>(linkBuffer.locationOf<JSInternalPtrTag>(record.targetToCheck)),
linkBuffer.locationOfNearCall<JSInternalPtrTag>(record.fastCall));
}
for (JSDirectCallRecord& record : m_jsDirectCalls) {
CallLinkInfo& info = *record.info;
linkBuffer.link(record.call, linkBuffer.locationOf<NoPtrTag>(record.slowPath));
info.setCallLocations(
CodeLocationLabel<JSInternalPtrTag>(),
linkBuffer.locationOf<JSInternalPtrTag>(record.slowPath),
linkBuffer.locationOfNearCall<JSInternalPtrTag>(record.call));
}
for (JSDirectTailCallRecord& record : m_jsDirectTailCalls) {
CallLinkInfo& info = *record.info;
info.setCallLocations(
linkBuffer.locationOf<JSInternalPtrTag>(record.patchableJump),
linkBuffer.locationOf<JSInternalPtrTag>(record.slowPath),
linkBuffer.locationOfNearCall<JSInternalPtrTag>(record.call));
}
MacroAssemblerCodeRef<JITThunkPtrTag> osrExitThunk = vm().getCTIStub(osrExitGenerationThunkGenerator);
auto target = CodeLocationLabel<JITThunkPtrTag>(osrExitThunk.code());
for (unsigned i = 0; i < m_jitCode->osrExit.size(); ++i) {
OSRExitCompilationInfo& info = m_exitCompilationInfo[i];
if (!Options::useProbeOSRExit()) {
linkBuffer.link(info.m_patchableJump.m_jump, target);
OSRExit& exit = m_jitCode->osrExit[i];
exit.m_patchableJumpLocation = linkBuffer.locationOf<JSInternalPtrTag>(info.m_patchableJump);
}
if (info.m_replacementSource.isSet()) {
m_jitCode->common.jumpReplacements.append(JumpReplacement(
linkBuffer.locationOf<JSInternalPtrTag>(info.m_replacementSource),
linkBuffer.locationOf<OSRExitPtrTag>(info.m_replacementDestination)));
}
}
if (UNLIKELY(m_graph.compilation())) {
ASSERT(m_exitSiteLabels.size() == m_jitCode->osrExit.size());
for (unsigned i = 0; i < m_exitSiteLabels.size(); ++i) {
Vector<Label>& labels = m_exitSiteLabels[i];
Vector<MacroAssemblerCodePtr<JSInternalPtrTag>> addresses;
for (unsigned j = 0; j < labels.size(); ++j)
addresses.append(linkBuffer.locationOf<JSInternalPtrTag>(labels[j]));
m_graph.compilation()->addOSRExitSite(addresses);
}
} else
ASSERT(!m_exitSiteLabels.size());
m_jitCode->common.compilation = m_graph.compilation();
// Link new DFG exception handlers and remove baseline JIT handlers.
m_codeBlock->clearExceptionHandlers();
for (unsigned i = 0; i < m_exceptionHandlerOSRExitCallSites.size(); i++) {
OSRExitCompilationInfo& info = m_exceptionHandlerOSRExitCallSites[i].exitInfo;
if (info.m_replacementDestination.isSet()) {
// If this is is *not* set, it means that we already jumped to the OSR exit in pure generated control flow.
// i.e, we explicitly emitted an exceptionCheck that we know will be caught in this machine frame.
// If this *is set*, it means we will be landing at this code location from genericUnwind from an
// exception thrown in a child call frame.
CodeLocationLabel<ExceptionHandlerPtrTag> catchLabel = linkBuffer.locationOf<ExceptionHandlerPtrTag>(info.m_replacementDestination);
HandlerInfo newExceptionHandler = m_exceptionHandlerOSRExitCallSites[i].baselineExceptionHandler;
CallSiteIndex callSite = m_exceptionHandlerOSRExitCallSites[i].callSiteIndex;
newExceptionHandler.start = callSite.bits();
newExceptionHandler.end = callSite.bits() + 1;
newExceptionHandler.nativeCode = catchLabel;
m_codeBlock->appendExceptionHandler(newExceptionHandler);
}
}
if (m_pcToCodeOriginMapBuilder.didBuildMapping())
m_codeBlock->setPCToCodeOriginMap(makeUnique<PCToCodeOriginMap>(WTFMove(m_pcToCodeOriginMapBuilder), linkBuffer));
}
static void emitStackOverflowCheck(JITCompiler& jit, MacroAssembler::JumpList& stackOverflow)
{
int frameTopOffset = virtualRegisterForLocal(jit.graph().requiredRegisterCountForExecutionAndExit() - 1).offset() * sizeof(Register);
unsigned maxFrameSize = -frameTopOffset;
jit.addPtr(MacroAssembler::TrustedImm32(frameTopOffset), GPRInfo::callFrameRegister, GPRInfo::regT1);
if (UNLIKELY(maxFrameSize > Options::reservedZoneSize()))
stackOverflow.append(jit.branchPtr(MacroAssembler::Above, GPRInfo::regT1, GPRInfo::callFrameRegister));
stackOverflow.append(jit.branchPtr(MacroAssembler::Above, MacroAssembler::AbsoluteAddress(jit.vm().addressOfSoftStackLimit()), GPRInfo::regT1));
}
void JITCompiler::compile()
{
makeCatchOSREntryBuffer();
setStartOfCode();
compileEntry();
m_speculative = makeUnique<SpeculativeJIT>(*this);
// Plant a check that sufficient space is available in the JSStack.
JumpList stackOverflow;
emitStackOverflowCheck(*this, stackOverflow);
addPtr(TrustedImm32(-(m_graph.frameRegisterCount() * sizeof(Register))), GPRInfo::callFrameRegister, stackPointerRegister);
checkStackPointerAlignment();
compileSetupRegistersForEntry();
compileEntryExecutionFlag();
compileBody();
setEndOfMainPath();
// === Footer code generation ===
//
// Generate the stack overflow handling; if the stack check in the entry head fails,
// we need to call out to a helper function to throw the StackOverflowError.
stackOverflow.link(this);
emitStoreCodeOrigin(CodeOrigin(BytecodeIndex(0)));
if (maxFrameExtentForSlowPathCall)
addPtr(TrustedImm32(-static_cast<int32_t>(maxFrameExtentForSlowPathCall)), stackPointerRegister);
m_speculative->callOperationWithCallFrameRollbackOnException(operationThrowStackOverflowError, m_codeBlock);
// Generate slow path code.
m_speculative->runSlowPathGenerators(m_pcToCodeOriginMapBuilder);
m_pcToCodeOriginMapBuilder.appendItem(labelIgnoringWatchpoints(), PCToCodeOriginMapBuilder::defaultCodeOrigin());
compileExceptionHandlers();
linkOSRExits();
// Create OSR entry trampolines if necessary.
m_speculative->createOSREntries();
setEndOfCode();
auto linkBuffer = makeUnique<LinkBuffer>(*this, m_codeBlock, JITCompilationCanFail);
if (linkBuffer->didFailToAllocate()) {
m_graph.m_plan.setFinalizer(makeUnique<FailedFinalizer>(m_graph.m_plan));
return;
}
link(*linkBuffer);
m_speculative->linkOSREntries(*linkBuffer);
disassemble(*linkBuffer);
m_graph.m_plan.setFinalizer(makeUnique<JITFinalizer>(
m_graph.m_plan, m_jitCode.releaseNonNull(), WTFMove(linkBuffer)));
}
void JITCompiler::compileFunction()
{
makeCatchOSREntryBuffer();
setStartOfCode();
Label entryLabel(this);
compileEntry();
// === Function header code generation ===
// This is the main entry point, without performing an arity check.
// If we needed to perform an arity check we will already have moved the return address,
// so enter after this.
Label fromArityCheck(this);
// Plant a check that sufficient space is available in the JSStack.
JumpList stackOverflow;
emitStackOverflowCheck(*this, stackOverflow);
// Move the stack pointer down to accommodate locals
addPtr(TrustedImm32(-(m_graph.frameRegisterCount() * sizeof(Register))), GPRInfo::callFrameRegister, stackPointerRegister);
checkStackPointerAlignment();
compileSetupRegistersForEntry();
compileEntryExecutionFlag();
// === Function body code generation ===
m_speculative = makeUnique<SpeculativeJIT>(*this);
compileBody();
setEndOfMainPath();
// === Function footer code generation ===
//
// Generate code to perform the stack overflow handling (if the stack check in
// the function header fails), and generate the entry point with arity check.
//
// Generate the stack overflow handling; if the stack check in the function head fails,
// we need to call out to a helper function to throw the StackOverflowError.
stackOverflow.link(this);
emitStoreCodeOrigin(CodeOrigin(BytecodeIndex(0)));
if (maxFrameExtentForSlowPathCall)
addPtr(TrustedImm32(-static_cast<int32_t>(maxFrameExtentForSlowPathCall)), stackPointerRegister);
m_speculative->callOperationWithCallFrameRollbackOnException(operationThrowStackOverflowError, m_codeBlock);
// The fast entry point into a function does not check the correct number of arguments
// have been passed to the call (we only use the fast entry point where we can statically
// determine the correct number of arguments have been passed, or have already checked).
// In cases where an arity check is necessary, we enter here.
// FIXME: change this from a cti call to a DFG style operation (normal C calling conventions).
Call callArityFixup;
Label arityCheck;
bool requiresArityFixup = m_codeBlock->numParameters() != 1;
if (requiresArityFixup) {
arityCheck = label();
compileEntry();
load32(AssemblyHelpers::payloadFor((VirtualRegister)CallFrameSlot::argumentCountIncludingThis), GPRInfo::regT1);
branch32(AboveOrEqual, GPRInfo::regT1, TrustedImm32(m_codeBlock->numParameters())).linkTo(fromArityCheck, this);
emitStoreCodeOrigin(CodeOrigin(BytecodeIndex(0)));
if (maxFrameExtentForSlowPathCall)
addPtr(TrustedImm32(-static_cast<int32_t>(maxFrameExtentForSlowPathCall)), stackPointerRegister);
m_speculative->callOperationWithCallFrameRollbackOnException(m_codeBlock->isConstructor() ? operationConstructArityCheck : operationCallArityCheck, GPRInfo::regT0, m_codeBlock->globalObject());
if (maxFrameExtentForSlowPathCall)
addPtr(TrustedImm32(maxFrameExtentForSlowPathCall), stackPointerRegister);
branchTest32(Zero, GPRInfo::returnValueGPR).linkTo(fromArityCheck, this);
emitStoreCodeOrigin(CodeOrigin(BytecodeIndex(0)));
move(GPRInfo::returnValueGPR, GPRInfo::argumentGPR0);
callArityFixup = nearCall();
jump(fromArityCheck);
} else
arityCheck = entryLabel;
// Generate slow path code.
m_speculative->runSlowPathGenerators(m_pcToCodeOriginMapBuilder);
m_pcToCodeOriginMapBuilder.appendItem(labelIgnoringWatchpoints(), PCToCodeOriginMapBuilder::defaultCodeOrigin());
compileExceptionHandlers();
linkOSRExits();
// Create OSR entry trampolines if necessary.
m_speculative->createOSREntries();
setEndOfCode();
// === Link ===
auto linkBuffer = makeUnique<LinkBuffer>(*this, m_codeBlock, JITCompilationCanFail);
if (linkBuffer->didFailToAllocate()) {
m_graph.m_plan.setFinalizer(makeUnique<FailedFinalizer>(m_graph.m_plan));
return;
}
link(*linkBuffer);
m_speculative->linkOSREntries(*linkBuffer);
if (requiresArityFixup)
linkBuffer->link(callArityFixup, FunctionPtr<JITThunkPtrTag>(vm().getCTIStub(arityFixupGenerator).code()));
disassemble(*linkBuffer);
MacroAssemblerCodePtr<JSEntryPtrTag> withArityCheck = linkBuffer->locationOf<JSEntryPtrTag>(arityCheck);
m_graph.m_plan.setFinalizer(makeUnique<JITFinalizer>(
m_graph.m_plan, m_jitCode.releaseNonNull(), WTFMove(linkBuffer), withArityCheck));
}
void JITCompiler::disassemble(LinkBuffer& linkBuffer)
{
if (shouldDumpDisassembly()) {
m_disassembler->dump(linkBuffer);
linkBuffer.didAlreadyDisassemble();
}
if (UNLIKELY(m_graph.m_plan.compilation()))
m_disassembler->reportToProfiler(m_graph.m_plan.compilation(), linkBuffer);
}
#if USE(JSVALUE32_64)
void* JITCompiler::addressOfDoubleConstant(Node* node)
{
double value = node->asNumber();
int64_t valueBits = bitwise_cast<int64_t>(value);
auto it = m_graph.m_doubleConstantsMap.find(valueBits);
if (it != m_graph.m_doubleConstantsMap.end())
return it->second;
if (!m_graph.m_doubleConstants)
m_graph.m_doubleConstants = makeUnique<Bag<double>>();
double* addressInConstantPool = m_graph.m_doubleConstants->add();
*addressInConstantPool = value;
m_graph.m_doubleConstantsMap[valueBits] = addressInConstantPool;
return addressInConstantPool;
}
#endif
void JITCompiler::noticeCatchEntrypoint(BasicBlock& basicBlock, JITCompiler::Label blockHead, LinkBuffer& linkBuffer, Vector<FlushFormat>&& argumentFormats)
{
RELEASE_ASSERT(basicBlock.isCatchEntrypoint);
RELEASE_ASSERT(basicBlock.intersectionOfCFAHasVisited); // An entrypoint is reachable by definition.
m_jitCode->common.appendCatchEntrypoint(basicBlock.bytecodeBegin, linkBuffer.locationOf<ExceptionHandlerPtrTag>(blockHead), WTFMove(argumentFormats));
}
void JITCompiler::noticeOSREntry(BasicBlock& basicBlock, JITCompiler::Label blockHead, LinkBuffer& linkBuffer)
{
RELEASE_ASSERT(!basicBlock.isCatchEntrypoint);
// OSR entry is not allowed into blocks deemed unreachable by control flow analysis.
if (!basicBlock.intersectionOfCFAHasVisited)
return;
OSREntryData* entry = m_jitCode->appendOSREntryData(basicBlock.bytecodeBegin, linkBuffer.locationOf<OSREntryPtrTag>(blockHead));
entry->m_expectedValues = basicBlock.intersectionOfPastValuesAtHead;
// Fix the expected values: in our protocol, a dead variable will have an expected
// value of (None, []). But the old JIT may stash some values there. So we really
// need (Top, TOP).
for (size_t argument = 0; argument < basicBlock.variablesAtHead.numberOfArguments(); ++argument) {
Node* node = basicBlock.variablesAtHead.argument(argument);
if (!node || !node->shouldGenerate())
entry->m_expectedValues.argument(argument).makeBytecodeTop();
}
for (size_t local = 0; local < basicBlock.variablesAtHead.numberOfLocals(); ++local) {
Node* node = basicBlock.variablesAtHead.local(local);
if (!node || !node->shouldGenerate())
entry->m_expectedValues.local(local).makeBytecodeTop();
else {
VariableAccessData* variable = node->variableAccessData();
entry->m_machineStackUsed.set(variable->machineLocal().toLocal());
switch (variable->flushFormat()) {
case FlushedDouble:
entry->m_localsForcedDouble.set(local);
break;
case FlushedInt52:
entry->m_localsForcedAnyInt.set(local);
break;
default:
break;
}
ASSERT(!variable->operand().isTmp());
if (variable->operand().virtualRegister() != variable->machineLocal()) {
entry->m_reshufflings.append(
OSREntryReshuffling(
variable->operand().virtualRegister().offset(), variable->machineLocal().offset()));
}
}
}
entry->m_reshufflings.shrinkToFit();
}
void JITCompiler::appendExceptionHandlingOSRExit(ExitKind kind, unsigned eventStreamIndex, CodeOrigin opCatchOrigin, HandlerInfo* exceptionHandler, CallSiteIndex callSite, MacroAssembler::JumpList jumpsToFail)
{
OSRExit exit(kind, JSValueRegs(), MethodOfGettingAValueProfile(), m_speculative.get(), eventStreamIndex);
exit.m_codeOrigin = opCatchOrigin;
exit.m_exceptionHandlerCallSiteIndex = callSite;
OSRExitCompilationInfo& exitInfo = appendExitInfo(jumpsToFail);
jitCode()->appendOSRExit(exit);
m_exceptionHandlerOSRExitCallSites.append(ExceptionHandlingOSRExitInfo { exitInfo, *exceptionHandler, callSite });
}
void JITCompiler::exceptionCheck()
{
// It's important that we use origin.forExit here. Consider if we hoist string
// addition outside a loop, and that we exit at the point of that concatenation
// from an out of memory exception.
// If the original loop had a try/catch around string concatenation, if we "catch"
// that exception inside the loop, then the loops induction variable will be undefined
// in the OSR exit value recovery. It's more defensible for the string concatenation,
// then, to not be caught by the for loops' try/catch.
// Here is the program I'm speaking about:
//
// >>>> lets presume "c = a + b" gets hoisted here.
// for (var i = 0; i < length; i++) {
// try {
// c = a + b
// } catch(e) {
// If we threw an out of memory error, and we cought the exception
// right here, then "i" would almost certainly be undefined, which
// would make no sense.
// ...
// }
// }
CodeOrigin opCatchOrigin;
HandlerInfo* exceptionHandler;
bool willCatchException = m_graph.willCatchExceptionInMachineFrame(m_speculative->m_currentNode->origin.forExit, opCatchOrigin, exceptionHandler);
if (willCatchException) {
unsigned streamIndex = m_speculative->m_outOfLineStreamIndex ? *m_speculative->m_outOfLineStreamIndex : m_speculative->m_stream->size();
MacroAssembler::Jump hadException = emitNonPatchableExceptionCheck(vm());
// We assume here that this is called after callOpeartion()/appendCall() is called.
appendExceptionHandlingOSRExit(ExceptionCheck, streamIndex, opCatchOrigin, exceptionHandler, m_jitCode->common.codeOrigins->lastCallSite(), hadException);
} else
m_exceptionChecks.append(emitExceptionCheck(vm()));
}
CallSiteIndex JITCompiler::recordCallSiteAndGenerateExceptionHandlingOSRExitIfNeeded(const CodeOrigin& callSiteCodeOrigin, unsigned eventStreamIndex)
{
CodeOrigin opCatchOrigin;
HandlerInfo* exceptionHandler;
bool willCatchException = m_graph.willCatchExceptionInMachineFrame(callSiteCodeOrigin, opCatchOrigin, exceptionHandler);
CallSiteIndex callSite = addCallSite(callSiteCodeOrigin);
if (willCatchException)
appendExceptionHandlingOSRExit(GenericUnwind, eventStreamIndex, opCatchOrigin, exceptionHandler, callSite);
return callSite;
}
void JITCompiler::setEndOfMainPath()
{
m_pcToCodeOriginMapBuilder.appendItem(labelIgnoringWatchpoints(), m_speculative->m_origin.semantic);
if (LIKELY(!m_disassembler))
return;
m_disassembler->setEndOfMainPath(labelIgnoringWatchpoints());
}
void JITCompiler::setEndOfCode()
{
m_pcToCodeOriginMapBuilder.appendItem(labelIgnoringWatchpoints(), PCToCodeOriginMapBuilder::defaultCodeOrigin());
if (LIKELY(!m_disassembler))
return;
m_disassembler->setEndOfCode(labelIgnoringWatchpoints());
}
void JITCompiler::makeCatchOSREntryBuffer()
{
if (m_graph.m_maxLocalsForCatchOSREntry) {
uint32_t numberOfLiveLocals = std::max(*m_graph.m_maxLocalsForCatchOSREntry, 1u); // Make sure we always allocate a non-null catchOSREntryBuffer.
m_jitCode->common.catchOSREntryBuffer = vm().scratchBufferForSize(sizeof(JSValue) * numberOfLiveLocals);
}
}
} } // namespace JSC::DFG
#endif // ENABLE(DFG_JIT)
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