| /* |
| * Copyright (C) 2014-2020 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 "PolymorphicAccess.h" |
| |
| #if ENABLE(JIT) |
| |
| #include "BinarySwitch.h" |
| #include "CCallHelpers.h" |
| #include "CacheableIdentifierInlines.h" |
| #include "CodeBlock.h" |
| #include "FullCodeOrigin.h" |
| #include "Heap.h" |
| #include "JITOperations.h" |
| #include "LinkBuffer.h" |
| #include "StructureInlines.h" |
| #include "StructureStubClearingWatchpoint.h" |
| #include "StructureStubInfo.h" |
| #include "SuperSampler.h" |
| #include <wtf/CommaPrinter.h> |
| #include <wtf/ListDump.h> |
| |
| namespace JSC { |
| |
| namespace PolymorphicAccessInternal { |
| static constexpr bool verbose = false; |
| } |
| |
| DEFINE_ALLOCATOR_WITH_HEAP_IDENTIFIER(PolymorphicAccess); |
| |
| void AccessGenerationResult::dump(PrintStream& out) const |
| { |
| out.print(m_kind); |
| if (m_code) |
| out.print(":", m_code); |
| } |
| |
| void AccessGenerationState::installWatchpoint(const ObjectPropertyCondition& condition) |
| { |
| WatchpointsOnStructureStubInfo::ensureReferenceAndInstallWatchpoint( |
| watchpoints, jit->codeBlock(), stubInfo, condition); |
| } |
| |
| void AccessGenerationState::restoreScratch() |
| { |
| allocator->restoreReusedRegistersByPopping(*jit, preservedReusedRegisterState); |
| } |
| |
| void AccessGenerationState::succeed() |
| { |
| restoreScratch(); |
| success.append(jit->jump()); |
| } |
| |
| const RegisterSet& AccessGenerationState::liveRegistersForCall() |
| { |
| if (!m_calculatedRegistersForCallAndExceptionHandling) |
| calculateLiveRegistersForCallAndExceptionHandling(); |
| return m_liveRegistersForCall; |
| } |
| |
| const RegisterSet& AccessGenerationState::liveRegistersToPreserveAtExceptionHandlingCallSite() |
| { |
| if (!m_calculatedRegistersForCallAndExceptionHandling) |
| calculateLiveRegistersForCallAndExceptionHandling(); |
| return m_liveRegistersToPreserveAtExceptionHandlingCallSite; |
| } |
| |
| static RegisterSet calleeSaveRegisters() |
| { |
| RegisterSet result = RegisterSet::registersToNotSaveForJSCall(); |
| result.filter(RegisterSet::registersToNotSaveForCCall()); |
| return result; |
| } |
| |
| const RegisterSet& AccessGenerationState::calculateLiveRegistersForCallAndExceptionHandling() |
| { |
| if (!m_calculatedRegistersForCallAndExceptionHandling) { |
| m_calculatedRegistersForCallAndExceptionHandling = true; |
| |
| m_liveRegistersToPreserveAtExceptionHandlingCallSite = jit->codeBlock()->jitCode()->liveRegistersToPreserveAtExceptionHandlingCallSite(jit->codeBlock(), stubInfo->callSiteIndex); |
| m_needsToRestoreRegistersIfException = m_liveRegistersToPreserveAtExceptionHandlingCallSite.numberOfSetRegisters() > 0; |
| if (m_needsToRestoreRegistersIfException) |
| RELEASE_ASSERT(JITCode::isOptimizingJIT(jit->codeBlock()->jitType())); |
| |
| m_liveRegistersForCall = RegisterSet(m_liveRegistersToPreserveAtExceptionHandlingCallSite, allocator->usedRegisters()); |
| m_liveRegistersForCall.exclude(calleeSaveRegisters()); |
| } |
| return m_liveRegistersForCall; |
| } |
| |
| auto AccessGenerationState::preserveLiveRegistersToStackForCall(const RegisterSet& extra) -> SpillState |
| { |
| RegisterSet liveRegisters = liveRegistersForCall(); |
| liveRegisters.merge(extra); |
| |
| unsigned extraStackPadding = 0; |
| unsigned numberOfStackBytesUsedForRegisterPreservation = ScratchRegisterAllocator::preserveRegistersToStackForCall(*jit, liveRegisters, extraStackPadding); |
| return SpillState { |
| WTFMove(liveRegisters), |
| numberOfStackBytesUsedForRegisterPreservation |
| }; |
| } |
| |
| void AccessGenerationState::restoreLiveRegistersFromStackForCallWithThrownException(const SpillState& spillState) |
| { |
| // Even if we're a getter, we don't want to ignore the result value like we normally do |
| // because the getter threw, and therefore, didn't return a value that means anything. |
| // Instead, we want to restore that register to what it was upon entering the getter |
| // inline cache. The subtlety here is if the base and the result are the same register, |
| // and the getter threw, we want OSR exit to see the original base value, not the result |
| // of the getter call. |
| RegisterSet dontRestore = spillState.spilledRegisters; |
| // As an optimization here, we only need to restore what is live for exception handling. |
| // We can construct the dontRestore set to accomplish this goal by having it contain only |
| // what is live for call but not live for exception handling. By ignoring things that are |
| // only live at the call but not the exception handler, we will only restore things live |
| // at the exception handler. |
| dontRestore.exclude(liveRegistersToPreserveAtExceptionHandlingCallSite()); |
| restoreLiveRegistersFromStackForCall(spillState, dontRestore); |
| } |
| |
| void AccessGenerationState::restoreLiveRegistersFromStackForCall(const SpillState& spillState, const RegisterSet& dontRestore) |
| { |
| unsigned extraStackPadding = 0; |
| ScratchRegisterAllocator::restoreRegistersFromStackForCall(*jit, spillState.spilledRegisters, dontRestore, spillState.numberOfStackBytesUsedForRegisterPreservation, extraStackPadding); |
| } |
| |
| CallSiteIndex AccessGenerationState::callSiteIndexForExceptionHandlingOrOriginal() |
| { |
| if (!m_calculatedRegistersForCallAndExceptionHandling) |
| calculateLiveRegistersForCallAndExceptionHandling(); |
| |
| if (!m_calculatedCallSiteIndex) { |
| m_calculatedCallSiteIndex = true; |
| |
| if (m_needsToRestoreRegistersIfException) |
| m_callSiteIndex = jit->codeBlock()->newExceptionHandlingCallSiteIndex(stubInfo->callSiteIndex); |
| else |
| m_callSiteIndex = originalCallSiteIndex(); |
| } |
| |
| return m_callSiteIndex; |
| } |
| |
| DisposableCallSiteIndex AccessGenerationState::callSiteIndexForExceptionHandling() |
| { |
| RELEASE_ASSERT(m_calculatedRegistersForCallAndExceptionHandling); |
| RELEASE_ASSERT(m_needsToRestoreRegistersIfException); |
| RELEASE_ASSERT(m_calculatedCallSiteIndex); |
| return DisposableCallSiteIndex::fromCallSiteIndex(m_callSiteIndex); |
| } |
| |
| const HandlerInfo& AccessGenerationState::originalExceptionHandler() |
| { |
| if (!m_calculatedRegistersForCallAndExceptionHandling) |
| calculateLiveRegistersForCallAndExceptionHandling(); |
| |
| RELEASE_ASSERT(m_needsToRestoreRegistersIfException); |
| HandlerInfo* exceptionHandler = jit->codeBlock()->handlerForIndex(stubInfo->callSiteIndex.bits()); |
| RELEASE_ASSERT(exceptionHandler); |
| return *exceptionHandler; |
| } |
| |
| CallSiteIndex AccessGenerationState::originalCallSiteIndex() const { return stubInfo->callSiteIndex; } |
| |
| void AccessGenerationState::emitExplicitExceptionHandler() |
| { |
| restoreScratch(); |
| jit->pushToSave(GPRInfo::regT0); |
| jit->loadPtr(&m_vm.topEntryFrame, GPRInfo::regT0); |
| jit->copyCalleeSavesToEntryFrameCalleeSavesBuffer(GPRInfo::regT0); |
| jit->popToRestore(GPRInfo::regT0); |
| |
| if (needsToRestoreRegistersIfException()) { |
| // To the JIT that produces the original exception handling |
| // call site, they will expect the OSR exit to be arrived |
| // at from genericUnwind. Therefore we must model what genericUnwind |
| // does here. I.e, set callFrameForCatch and copy callee saves. |
| |
| jit->storePtr(GPRInfo::callFrameRegister, m_vm.addressOfCallFrameForCatch()); |
| CCallHelpers::Jump jumpToOSRExitExceptionHandler = jit->jump(); |
| |
| // We don't need to insert a new exception handler in the table |
| // because we're doing a manual exception check here. i.e, we'll |
| // never arrive here from genericUnwind(). |
| HandlerInfo originalHandler = originalExceptionHandler(); |
| jit->addLinkTask( |
| [=] (LinkBuffer& linkBuffer) { |
| linkBuffer.link(jumpToOSRExitExceptionHandler, originalHandler.nativeCode); |
| }); |
| } else { |
| jit->setupArguments<decltype(operationLookupExceptionHandler)>(CCallHelpers::TrustedImmPtr(&m_vm)); |
| jit->prepareCallOperation(m_vm); |
| CCallHelpers::Call lookupExceptionHandlerCall = jit->call(OperationPtrTag); |
| jit->addLinkTask( |
| [=] (LinkBuffer& linkBuffer) { |
| linkBuffer.link(lookupExceptionHandlerCall, FunctionPtr<OperationPtrTag>(operationLookupExceptionHandler)); |
| }); |
| jit->jumpToExceptionHandler(m_vm); |
| } |
| } |
| |
| PolymorphicAccess::PolymorphicAccess() { } |
| PolymorphicAccess::~PolymorphicAccess() { } |
| |
| AccessGenerationResult PolymorphicAccess::addCases( |
| const GCSafeConcurrentJSLocker& locker, VM& vm, CodeBlock* codeBlock, StructureStubInfo& stubInfo, |
| Vector<std::unique_ptr<AccessCase>, 2> originalCasesToAdd) |
| { |
| SuperSamplerScope superSamplerScope(false); |
| |
| // This method will add the originalCasesToAdd to the list one at a time while preserving the |
| // invariants: |
| // - If a newly added case canReplace() any existing case, then the existing case is removed before |
| // the new case is added. Removal doesn't change order of the list. Any number of existing cases |
| // can be removed via the canReplace() rule. |
| // - Cases in the list always appear in ascending order of time of addition. Therefore, if you |
| // cascade through the cases in reverse order, you will get the most recent cases first. |
| // - If this method fails (returns null, doesn't add the cases), then both the previous case list |
| // and the previous stub are kept intact and the new cases are destroyed. It's OK to attempt to |
| // add more things after failure. |
| |
| // First ensure that the originalCasesToAdd doesn't contain duplicates. |
| Vector<std::unique_ptr<AccessCase>> casesToAdd; |
| for (unsigned i = 0; i < originalCasesToAdd.size(); ++i) { |
| std::unique_ptr<AccessCase> myCase = WTFMove(originalCasesToAdd[i]); |
| |
| // Add it only if it is not replaced by the subsequent cases in the list. |
| bool found = false; |
| for (unsigned j = i + 1; j < originalCasesToAdd.size(); ++j) { |
| if (originalCasesToAdd[j]->canReplace(*myCase)) { |
| found = true; |
| break; |
| } |
| } |
| |
| if (found) |
| continue; |
| |
| casesToAdd.append(WTFMove(myCase)); |
| } |
| |
| if (PolymorphicAccessInternal::verbose) |
| dataLog("casesToAdd: ", listDump(casesToAdd), "\n"); |
| |
| // If there aren't any cases to add, then fail on the grounds that there's no point to generating a |
| // new stub that will be identical to the old one. Returning null should tell the caller to just |
| // keep doing what they were doing before. |
| if (casesToAdd.isEmpty()) |
| return AccessGenerationResult::MadeNoChanges; |
| |
| if (stubInfo.accessType != AccessType::InstanceOf) { |
| bool shouldReset = false; |
| AccessGenerationResult resetResult(AccessGenerationResult::ResetStubAndFireWatchpoints); |
| auto considerPolyProtoReset = [&] (Structure* a, Structure* b) { |
| if (Structure::shouldConvertToPolyProto(a, b)) { |
| // For now, we only reset if this is our first time invalidating this watchpoint. |
| // The reason we don't immediately fire this watchpoint is that we may be already |
| // watching the poly proto watchpoint, which if fired, would destroy us. We let |
| // the person handling the result to do a delayed fire. |
| ASSERT(a->rareData()->sharedPolyProtoWatchpoint().get() == b->rareData()->sharedPolyProtoWatchpoint().get()); |
| if (a->rareData()->sharedPolyProtoWatchpoint()->isStillValid()) { |
| shouldReset = true; |
| resetResult.addWatchpointToFire(*a->rareData()->sharedPolyProtoWatchpoint(), StringFireDetail("Detected poly proto optimization opportunity.")); |
| } |
| } |
| }; |
| |
| for (auto& caseToAdd : casesToAdd) { |
| for (auto& existingCase : m_list) { |
| Structure* a = caseToAdd->structure(); |
| Structure* b = existingCase->structure(); |
| considerPolyProtoReset(a, b); |
| } |
| } |
| for (unsigned i = 0; i < casesToAdd.size(); ++i) { |
| for (unsigned j = i + 1; j < casesToAdd.size(); ++j) { |
| Structure* a = casesToAdd[i]->structure(); |
| Structure* b = casesToAdd[j]->structure(); |
| considerPolyProtoReset(a, b); |
| } |
| } |
| |
| if (shouldReset) |
| return resetResult; |
| } |
| |
| // Now add things to the new list. Note that at this point, we will still have old cases that |
| // may be replaced by the new ones. That's fine. We will sort that out when we regenerate. |
| for (auto& caseToAdd : casesToAdd) { |
| commit(locker, vm, m_watchpoints, codeBlock, stubInfo, *caseToAdd); |
| m_list.append(WTFMove(caseToAdd)); |
| } |
| |
| if (PolymorphicAccessInternal::verbose) |
| dataLog("After addCases: m_list: ", listDump(m_list), "\n"); |
| |
| return AccessGenerationResult::Buffered; |
| } |
| |
| AccessGenerationResult PolymorphicAccess::addCase( |
| const GCSafeConcurrentJSLocker& locker, VM& vm, CodeBlock* codeBlock, StructureStubInfo& stubInfo, std::unique_ptr<AccessCase> newAccess) |
| { |
| Vector<std::unique_ptr<AccessCase>, 2> newAccesses; |
| newAccesses.append(WTFMove(newAccess)); |
| return addCases(locker, vm, codeBlock, stubInfo, WTFMove(newAccesses)); |
| } |
| |
| bool PolymorphicAccess::visitWeak(VM& vm) const |
| { |
| for (unsigned i = 0; i < size(); ++i) { |
| if (!at(i).visitWeak(vm)) |
| return false; |
| } |
| if (Vector<WriteBarrier<JSCell>>* weakReferences = m_weakReferences.get()) { |
| for (WriteBarrier<JSCell>& weakReference : *weakReferences) { |
| if (!vm.heap.isMarked(weakReference.get())) |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| bool PolymorphicAccess::propagateTransitions(SlotVisitor& visitor) const |
| { |
| bool result = true; |
| for (unsigned i = 0; i < size(); ++i) |
| result &= at(i).propagateTransitions(visitor); |
| return result; |
| } |
| |
| void PolymorphicAccess::visitAggregate(SlotVisitor& visitor) |
| { |
| for (unsigned i = 0; i < size(); ++i) |
| at(i).visitAggregate(visitor); |
| } |
| |
| void PolymorphicAccess::dump(PrintStream& out) const |
| { |
| out.print(RawPointer(this), ":["); |
| CommaPrinter comma; |
| for (auto& entry : m_list) |
| out.print(comma, *entry); |
| out.print("]"); |
| } |
| |
| void PolymorphicAccess::commit( |
| const GCSafeConcurrentJSLocker&, VM& vm, std::unique_ptr<WatchpointsOnStructureStubInfo>& watchpoints, CodeBlock* codeBlock, |
| StructureStubInfo& stubInfo, AccessCase& accessCase) |
| { |
| // NOTE: We currently assume that this is relatively rare. It mainly arises for accesses to |
| // properties on DOM nodes. For sure we cache many DOM node accesses, but even in |
| // Real Pages (TM), we appear to spend most of our time caching accesses to properties on |
| // vanilla objects or exotic objects from within JSC (like Arguments, those are super popular). |
| // Those common kinds of JSC object accesses don't hit this case. |
| |
| for (WatchpointSet* set : accessCase.commit(vm)) { |
| Watchpoint* watchpoint = |
| WatchpointsOnStructureStubInfo::ensureReferenceAndAddWatchpoint( |
| watchpoints, codeBlock, &stubInfo); |
| |
| set->add(watchpoint); |
| } |
| } |
| |
| AccessGenerationResult PolymorphicAccess::regenerate(const GCSafeConcurrentJSLocker& locker, VM& vm, JSGlobalObject* globalObject, CodeBlock* codeBlock, ECMAMode ecmaMode, StructureStubInfo& stubInfo) |
| { |
| SuperSamplerScope superSamplerScope(false); |
| |
| if (PolymorphicAccessInternal::verbose) |
| dataLog("Regenerate with m_list: ", listDump(m_list), "\n"); |
| |
| AccessGenerationState state(vm, globalObject, ecmaMode); |
| |
| state.access = this; |
| state.stubInfo = &stubInfo; |
| |
| state.baseGPR = stubInfo.baseGPR; |
| state.u.thisGPR = stubInfo.regs.thisGPR; |
| state.valueRegs = stubInfo.valueRegs(); |
| |
| // Regenerating is our opportunity to figure out what our list of cases should look like. We |
| // do this here. The newly produced 'cases' list may be smaller than m_list. We don't edit |
| // m_list in-place because we may still fail, in which case we want the PolymorphicAccess object |
| // to be unmutated. For sure, we want it to hang onto any data structures that may be referenced |
| // from the code of the current stub (aka previous). |
| ListType cases; |
| unsigned srcIndex = 0; |
| unsigned dstIndex = 0; |
| while (srcIndex < m_list.size()) { |
| std::unique_ptr<AccessCase> someCase = WTFMove(m_list[srcIndex++]); |
| |
| // If the case had been generated, then we have to keep the original in m_list in case we |
| // fail to regenerate. That case may have data structures that are used by the code that it |
| // had generated. If the case had not been generated, then we want to remove it from m_list. |
| bool isGenerated = someCase->state() == AccessCase::Generated; |
| |
| [&] () { |
| if (!someCase->couldStillSucceed()) |
| return; |
| |
| // Figure out if this is replaced by any later case. Given two cases A and B where A |
| // comes first in the case list, we know that A would have triggered first if we had |
| // generated the cases in a cascade. That's why this loop asks B->canReplace(A) but not |
| // A->canReplace(B). If A->canReplace(B) was true then A would never have requested |
| // repatching in cases where Repatch.cpp would have then gone on to generate B. If that |
| // did happen by some fluke, then we'd just miss the redundancy here, which wouldn't be |
| // incorrect - just slow. However, if A's checks failed and Repatch.cpp concluded that |
| // this new condition could be handled by B and B->canReplace(A), then this says that we |
| // don't need A anymore. |
| // |
| // If we can generate a binary switch, then A->canReplace(B) == B->canReplace(A). So, |
| // it doesn't matter that we only do the check in one direction. |
| for (unsigned j = srcIndex; j < m_list.size(); ++j) { |
| if (m_list[j]->canReplace(*someCase)) |
| return; |
| } |
| |
| if (isGenerated) |
| cases.append(someCase->clone()); |
| else |
| cases.append(WTFMove(someCase)); |
| }(); |
| |
| if (isGenerated) |
| m_list[dstIndex++] = WTFMove(someCase); |
| } |
| m_list.resize(dstIndex); |
| |
| ScratchRegisterAllocator allocator(stubInfo.usedRegisters); |
| state.allocator = &allocator; |
| allocator.lock(state.baseGPR); |
| if (state.u.thisGPR != InvalidGPRReg) |
| allocator.lock(state.u.thisGPR); |
| allocator.lock(state.valueRegs); |
| #if USE(JSVALUE32_64) |
| allocator.lock(stubInfo.baseTagGPR); |
| if (stubInfo.v.thisTagGPR != InvalidGPRReg) |
| allocator.lock(stubInfo.v.thisTagGPR); |
| #endif |
| |
| state.scratchGPR = allocator.allocateScratchGPR(); |
| |
| for (auto& accessCase : cases) { |
| if (accessCase->needsScratchFPR()) { |
| state.scratchFPR = allocator.allocateScratchFPR(); |
| break; |
| } |
| } |
| |
| CCallHelpers jit(codeBlock); |
| state.jit = &jit; |
| |
| state.preservedReusedRegisterState = |
| allocator.preserveReusedRegistersByPushing(jit, ScratchRegisterAllocator::ExtraStackSpace::NoExtraSpace); |
| |
| bool generatedFinalCode = false; |
| |
| // If the resulting set of cases is so big that we would stop caching and this is InstanceOf, |
| // then we want to generate the generic InstanceOf and then stop. |
| if (cases.size() >= Options::maxAccessVariantListSize() |
| && stubInfo.accessType == AccessType::InstanceOf) { |
| while (!cases.isEmpty()) |
| m_list.append(cases.takeLast()); |
| cases.append(AccessCase::create(vm, codeBlock, AccessCase::InstanceOfGeneric, nullptr)); |
| generatedFinalCode = true; |
| } |
| |
| if (PolymorphicAccessInternal::verbose) |
| dataLog("Optimized cases: ", listDump(cases), "\n"); |
| |
| // At this point we're convinced that 'cases' contains the cases that we want to JIT now and we |
| // won't change that set anymore. |
| |
| bool allGuardedByStructureCheck = true; |
| bool hasJSGetterSetterCall = false; |
| bool needsInt32PropertyCheck = false; |
| bool needsStringPropertyCheck = false; |
| bool needsSymbolPropertyCheck = false; |
| for (auto& newCase : cases) { |
| if (!stubInfo.hasConstantIdentifier) { |
| if (newCase->requiresIdentifierNameMatch()) { |
| if (newCase->uid()->isSymbol()) |
| needsSymbolPropertyCheck = true; |
| else |
| needsStringPropertyCheck = true; |
| } else if (newCase->requiresInt32PropertyCheck()) |
| needsInt32PropertyCheck = true; |
| } |
| commit(locker, vm, state.watchpoints, codeBlock, stubInfo, *newCase); |
| allGuardedByStructureCheck &= newCase->guardedByStructureCheck(stubInfo); |
| if (newCase->type() == AccessCase::Getter || newCase->type() == AccessCase::Setter) |
| hasJSGetterSetterCall = true; |
| } |
| |
| if (cases.isEmpty()) { |
| // This is super unlikely, but we make it legal anyway. |
| state.failAndRepatch.append(jit.jump()); |
| } else if (!allGuardedByStructureCheck || cases.size() == 1) { |
| // If there are any proxies in the list, we cannot just use a binary switch over the structure. |
| // We need to resort to a cascade. A cascade also happens to be optimal if we only have just |
| // one case. |
| CCallHelpers::JumpList fallThrough; |
| if (needsInt32PropertyCheck || needsStringPropertyCheck || needsSymbolPropertyCheck) { |
| if (needsInt32PropertyCheck) { |
| CCallHelpers::Jump notInt32; |
| |
| if (!stubInfo.propertyIsInt32) { |
| #if USE(JSVALUE64) |
| notInt32 = jit.branchIfNotInt32(state.u.propertyGPR); |
| #else |
| notInt32 = jit.branchIfNotInt32(state.stubInfo->v.propertyTagGPR); |
| #endif |
| } |
| for (unsigned i = cases.size(); i--;) { |
| fallThrough.link(&jit); |
| fallThrough.clear(); |
| if (cases[i]->requiresInt32PropertyCheck()) |
| cases[i]->generateWithGuard(state, fallThrough); |
| } |
| |
| if (needsStringPropertyCheck || needsSymbolPropertyCheck) { |
| if (notInt32.isSet()) |
| notInt32.link(&jit); |
| fallThrough.link(&jit); |
| fallThrough.clear(); |
| } else { |
| if (notInt32.isSet()) |
| state.failAndRepatch.append(notInt32); |
| } |
| } |
| |
| if (needsStringPropertyCheck) { |
| CCallHelpers::JumpList notString; |
| GPRReg propertyGPR = state.u.propertyGPR; |
| if (!stubInfo.propertyIsString) { |
| #if USE(JSVALUE32_64) |
| GPRReg propertyTagGPR = state.stubInfo->v.propertyTagGPR; |
| notString.append(jit.branchIfNotCell(propertyTagGPR)); |
| #else |
| notString.append(jit.branchIfNotCell(propertyGPR)); |
| #endif |
| notString.append(jit.branchIfNotString(propertyGPR)); |
| } |
| |
| jit.loadPtr(MacroAssembler::Address(propertyGPR, JSString::offsetOfValue()), state.scratchGPR); |
| |
| state.failAndRepatch.append(jit.branchIfRopeStringImpl(state.scratchGPR)); |
| |
| for (unsigned i = cases.size(); i--;) { |
| fallThrough.link(&jit); |
| fallThrough.clear(); |
| if (cases[i]->requiresIdentifierNameMatch() && !cases[i]->uid()->isSymbol()) |
| cases[i]->generateWithGuard(state, fallThrough); |
| } |
| |
| if (needsSymbolPropertyCheck) { |
| notString.link(&jit); |
| fallThrough.link(&jit); |
| fallThrough.clear(); |
| } else |
| state.failAndRepatch.append(notString); |
| } |
| |
| if (needsSymbolPropertyCheck) { |
| CCallHelpers::JumpList notSymbol; |
| if (!stubInfo.propertyIsSymbol) { |
| GPRReg propertyGPR = state.u.propertyGPR; |
| #if USE(JSVALUE32_64) |
| GPRReg propertyTagGPR = state.stubInfo->v.propertyTagGPR; |
| notSymbol.append(jit.branchIfNotCell(propertyTagGPR)); |
| #else |
| notSymbol.append(jit.branchIfNotCell(propertyGPR)); |
| #endif |
| notSymbol.append(jit.branchIfNotSymbol(propertyGPR)); |
| } |
| |
| for (unsigned i = cases.size(); i--;) { |
| fallThrough.link(&jit); |
| fallThrough.clear(); |
| if (cases[i]->requiresIdentifierNameMatch() && cases[i]->uid()->isSymbol()) |
| cases[i]->generateWithGuard(state, fallThrough); |
| } |
| |
| state.failAndRepatch.append(notSymbol); |
| } |
| } else { |
| // Cascade through the list, preferring newer entries. |
| for (unsigned i = cases.size(); i--;) { |
| fallThrough.link(&jit); |
| fallThrough.clear(); |
| cases[i]->generateWithGuard(state, fallThrough); |
| } |
| } |
| |
| state.failAndRepatch.append(fallThrough); |
| |
| } else { |
| jit.load32( |
| CCallHelpers::Address(state.baseGPR, JSCell::structureIDOffset()), |
| state.scratchGPR); |
| |
| Vector<int64_t> caseValues(cases.size()); |
| for (unsigned i = 0; i < cases.size(); ++i) |
| caseValues[i] = bitwise_cast<int32_t>(cases[i]->structure()->id()); |
| |
| BinarySwitch binarySwitch(state.scratchGPR, caseValues, BinarySwitch::Int32); |
| while (binarySwitch.advance(jit)) |
| cases[binarySwitch.caseIndex()]->generate(state); |
| state.failAndRepatch.append(binarySwitch.fallThrough()); |
| } |
| |
| if (!state.failAndIgnore.empty()) { |
| state.failAndIgnore.link(&jit); |
| |
| // Make sure that the inline cache optimization code knows that we are taking slow path because |
| // of something that isn't patchable. The slow path will decrement "countdown" and will only |
| // patch things if the countdown reaches zero. We increment the slow path count here to ensure |
| // that the slow path does not try to patch. |
| #if CPU(X86) || CPU(X86_64) |
| jit.move(CCallHelpers::TrustedImmPtr(&stubInfo.countdown), state.scratchGPR); |
| jit.add8(CCallHelpers::TrustedImm32(1), CCallHelpers::Address(state.scratchGPR)); |
| #else |
| jit.load8(&stubInfo.countdown, state.scratchGPR); |
| jit.add32(CCallHelpers::TrustedImm32(1), state.scratchGPR); |
| jit.store8(state.scratchGPR, &stubInfo.countdown); |
| #endif |
| } |
| |
| CCallHelpers::JumpList failure; |
| if (allocator.didReuseRegisters()) { |
| state.failAndRepatch.link(&jit); |
| state.restoreScratch(); |
| } else |
| failure = state.failAndRepatch; |
| failure.append(jit.jump()); |
| |
| CodeBlock* codeBlockThatOwnsExceptionHandlers = nullptr; |
| DisposableCallSiteIndex callSiteIndexForExceptionHandling; |
| if (state.needsToRestoreRegistersIfException() && hasJSGetterSetterCall) { |
| // Emit the exception handler. |
| // Note that this code is only reachable when doing genericUnwind from a pure JS getter/setter . |
| // Note also that this is not reachable from custom getter/setter. Custom getter/setters will have |
| // their own exception handling logic that doesn't go through genericUnwind. |
| MacroAssembler::Label makeshiftCatchHandler = jit.label(); |
| |
| int stackPointerOffset = codeBlock->stackPointerOffset() * sizeof(EncodedJSValue); |
| AccessGenerationState::SpillState spillStateForJSGetterSetter = state.spillStateForJSGetterSetter(); |
| ASSERT(!spillStateForJSGetterSetter.isEmpty()); |
| stackPointerOffset -= state.preservedReusedRegisterState.numberOfBytesPreserved; |
| stackPointerOffset -= spillStateForJSGetterSetter.numberOfStackBytesUsedForRegisterPreservation; |
| |
| jit.loadPtr(vm.addressOfCallFrameForCatch(), GPRInfo::callFrameRegister); |
| jit.addPtr(CCallHelpers::TrustedImm32(stackPointerOffset), GPRInfo::callFrameRegister, CCallHelpers::stackPointerRegister); |
| |
| state.restoreLiveRegistersFromStackForCallWithThrownException(spillStateForJSGetterSetter); |
| state.restoreScratch(); |
| CCallHelpers::Jump jumpToOSRExitExceptionHandler = jit.jump(); |
| |
| HandlerInfo oldHandler = state.originalExceptionHandler(); |
| DisposableCallSiteIndex newExceptionHandlingCallSite = state.callSiteIndexForExceptionHandling(); |
| jit.addLinkTask( |
| [=] (LinkBuffer& linkBuffer) { |
| linkBuffer.link(jumpToOSRExitExceptionHandler, oldHandler.nativeCode); |
| |
| HandlerInfo handlerToRegister = oldHandler; |
| handlerToRegister.nativeCode = linkBuffer.locationOf<ExceptionHandlerPtrTag>(makeshiftCatchHandler); |
| handlerToRegister.start = newExceptionHandlingCallSite.bits(); |
| handlerToRegister.end = newExceptionHandlingCallSite.bits() + 1; |
| codeBlock->appendExceptionHandler(handlerToRegister); |
| }); |
| |
| // We set these to indicate to the stub to remove itself from the CodeBlock's |
| // exception handler table when it is deallocated. |
| codeBlockThatOwnsExceptionHandlers = codeBlock; |
| ASSERT(JITCode::isOptimizingJIT(codeBlockThatOwnsExceptionHandlers->jitType())); |
| callSiteIndexForExceptionHandling = state.callSiteIndexForExceptionHandling(); |
| } |
| |
| LinkBuffer linkBuffer(jit, codeBlock, JITCompilationCanFail); |
| if (linkBuffer.didFailToAllocate()) { |
| if (PolymorphicAccessInternal::verbose) |
| dataLog("Did fail to allocate.\n"); |
| return AccessGenerationResult::GaveUp; |
| } |
| |
| CodeLocationLabel<JSInternalPtrTag> successLabel = stubInfo.doneLocation; |
| |
| linkBuffer.link(state.success, successLabel); |
| |
| linkBuffer.link(failure, stubInfo.slowPathStartLocation); |
| |
| if (PolymorphicAccessInternal::verbose) |
| dataLog(FullCodeOrigin(codeBlock, stubInfo.codeOrigin), ": Generating polymorphic access stub for ", listDump(cases), "\n"); |
| |
| MacroAssemblerCodeRef<JITStubRoutinePtrTag> code = FINALIZE_CODE_FOR( |
| codeBlock, linkBuffer, JITStubRoutinePtrTag, |
| "%s", toCString("Access stub for ", *codeBlock, " ", stubInfo.codeOrigin, " with return point ", successLabel, ": ", listDump(cases)).data()); |
| |
| bool doesCalls = false; |
| Vector<JSCell*> cellsToMark; |
| for (auto& entry : cases) |
| doesCalls |= entry->doesCalls(vm, &cellsToMark); |
| |
| m_stubRoutine = createJITStubRoutine(code, vm, codeBlock, doesCalls, cellsToMark, WTFMove(state.m_callLinkInfos), codeBlockThatOwnsExceptionHandlers, callSiteIndexForExceptionHandling); |
| m_watchpoints = WTFMove(state.watchpoints); |
| if (!state.weakReferences.isEmpty()) { |
| state.weakReferences.shrinkToFit(); |
| m_weakReferences = makeUnique<Vector<WriteBarrier<JSCell>>>(WTFMove(state.weakReferences)); |
| } |
| if (PolymorphicAccessInternal::verbose) |
| dataLog("Returning: ", code.code(), "\n"); |
| |
| m_list = WTFMove(cases); |
| m_list.shrinkToFit(); |
| |
| AccessGenerationResult::Kind resultKind; |
| if (m_list.size() >= Options::maxAccessVariantListSize() || generatedFinalCode) |
| resultKind = AccessGenerationResult::GeneratedFinalCode; |
| else |
| resultKind = AccessGenerationResult::GeneratedNewCode; |
| |
| return AccessGenerationResult(resultKind, code.code()); |
| } |
| |
| void PolymorphicAccess::aboutToDie() |
| { |
| if (m_stubRoutine) |
| m_stubRoutine->aboutToDie(); |
| } |
| |
| } // namespace JSC |
| |
| namespace WTF { |
| |
| using namespace JSC; |
| |
| void printInternal(PrintStream& out, AccessGenerationResult::Kind kind) |
| { |
| switch (kind) { |
| case AccessGenerationResult::MadeNoChanges: |
| out.print("MadeNoChanges"); |
| return; |
| case AccessGenerationResult::GaveUp: |
| out.print("GaveUp"); |
| return; |
| case AccessGenerationResult::Buffered: |
| out.print("Buffered"); |
| return; |
| case AccessGenerationResult::GeneratedNewCode: |
| out.print("GeneratedNewCode"); |
| return; |
| case AccessGenerationResult::GeneratedFinalCode: |
| out.print("GeneratedFinalCode"); |
| return; |
| case AccessGenerationResult::ResetStubAndFireWatchpoints: |
| out.print("ResetStubAndFireWatchpoints"); |
| return; |
| } |
| |
| RELEASE_ASSERT_NOT_REACHED(); |
| } |
| |
| void printInternal(PrintStream& out, AccessCase::AccessType type) |
| { |
| switch (type) { |
| case AccessCase::Load: |
| out.print("Load"); |
| return; |
| case AccessCase::Transition: |
| out.print("Transition"); |
| return; |
| case AccessCase::Delete: |
| out.print("Delete"); |
| return; |
| case AccessCase::DeleteNonConfigurable: |
| out.print("DeleteNonConfigurable"); |
| return; |
| case AccessCase::DeleteMiss: |
| out.print("DeleteMiss"); |
| return; |
| case AccessCase::Replace: |
| out.print("Replace"); |
| return; |
| case AccessCase::Miss: |
| out.print("Miss"); |
| return; |
| case AccessCase::GetGetter: |
| out.print("GetGetter"); |
| return; |
| case AccessCase::Getter: |
| out.print("Getter"); |
| return; |
| case AccessCase::Setter: |
| out.print("Setter"); |
| return; |
| case AccessCase::CustomValueGetter: |
| out.print("CustomValueGetter"); |
| return; |
| case AccessCase::CustomAccessorGetter: |
| out.print("CustomAccessorGetter"); |
| return; |
| case AccessCase::CustomValueSetter: |
| out.print("CustomValueSetter"); |
| return; |
| case AccessCase::CustomAccessorSetter: |
| out.print("CustomAccessorSetter"); |
| return; |
| case AccessCase::IntrinsicGetter: |
| out.print("IntrinsicGetter"); |
| return; |
| case AccessCase::InHit: |
| out.print("InHit"); |
| return; |
| case AccessCase::InMiss: |
| out.print("InMiss"); |
| return; |
| case AccessCase::ArrayLength: |
| out.print("ArrayLength"); |
| return; |
| case AccessCase::StringLength: |
| out.print("StringLength"); |
| return; |
| case AccessCase::DirectArgumentsLength: |
| out.print("DirectArgumentsLength"); |
| return; |
| case AccessCase::ScopedArgumentsLength: |
| out.print("ScopedArgumentsLength"); |
| return; |
| case AccessCase::ModuleNamespaceLoad: |
| out.print("ModuleNamespaceLoad"); |
| return; |
| case AccessCase::InstanceOfHit: |
| out.print("InstanceOfHit"); |
| return; |
| case AccessCase::InstanceOfMiss: |
| out.print("InstanceOfMiss"); |
| return; |
| case AccessCase::InstanceOfGeneric: |
| out.print("InstanceOfGeneric"); |
| return; |
| case AccessCase::IndexedInt32Load: |
| out.print("IndexedInt32Load"); |
| return; |
| case AccessCase::IndexedDoubleLoad: |
| out.print("IndexedDoubleLoad"); |
| return; |
| case AccessCase::IndexedContiguousLoad: |
| out.print("IndexedContiguousLoad"); |
| return; |
| case AccessCase::IndexedArrayStorageLoad: |
| out.print("IndexedArrayStorageLoad"); |
| return; |
| case AccessCase::IndexedScopedArgumentsLoad: |
| out.print("IndexedScopedArgumentsLoad"); |
| return; |
| case AccessCase::IndexedDirectArgumentsLoad: |
| out.print("IndexedDirectArgumentsLoad"); |
| return; |
| case AccessCase::IndexedTypedArrayInt8Load: |
| out.print("IndexedTypedArrayInt8Load"); |
| return; |
| case AccessCase::IndexedTypedArrayUint8Load: |
| out.print("IndexedTypedArrayUint8Load"); |
| return; |
| case AccessCase::IndexedTypedArrayUint8ClampedLoad: |
| out.print("IndexedTypedArrayUint8ClampedLoad"); |
| return; |
| case AccessCase::IndexedTypedArrayInt16Load: |
| out.print("IndexedTypedArrayInt16Load"); |
| return; |
| case AccessCase::IndexedTypedArrayUint16Load: |
| out.print("IndexedTypedArrayUint16Load"); |
| return; |
| case AccessCase::IndexedTypedArrayInt32Load: |
| out.print("IndexedTypedArrayInt32Load"); |
| return; |
| case AccessCase::IndexedTypedArrayUint32Load: |
| out.print("IndexedTypedArrayUint32Load"); |
| return; |
| case AccessCase::IndexedTypedArrayFloat32Load: |
| out.print("IndexedTypedArrayFloat32Load"); |
| return; |
| case AccessCase::IndexedTypedArrayFloat64Load: |
| out.print("IndexedTypedArrayFloat64Load"); |
| return; |
| case AccessCase::IndexedStringLoad: |
| out.print("IndexedStringLoad"); |
| return; |
| } |
| |
| RELEASE_ASSERT_NOT_REACHED(); |
| } |
| |
| void printInternal(PrintStream& out, AccessCase::State state) |
| { |
| switch (state) { |
| case AccessCase::Primordial: |
| out.print("Primordial"); |
| return; |
| case AccessCase::Committed: |
| out.print("Committed"); |
| return; |
| case AccessCase::Generated: |
| out.print("Generated"); |
| return; |
| } |
| |
| RELEASE_ASSERT_NOT_REACHED(); |
| } |
| |
| } // namespace WTF |
| |
| #endif // ENABLE(JIT) |
| |
| |
