| /* |
| * Copyright (C) 2008-2019 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 "StructureStubInfo.h" |
| |
| #include "JSObject.h" |
| #include "JSCInlines.h" |
| #include "PolymorphicAccess.h" |
| #include "Repatch.h" |
| |
| namespace JSC { |
| |
| #if ENABLE(JIT) |
| |
| namespace StructureStubInfoInternal { |
| static constexpr bool verbose = false; |
| } |
| |
| StructureStubInfo::StructureStubInfo(AccessType accessType) |
| : accessType(accessType) |
| , cacheType(CacheType::Unset) |
| , countdown(1) // For a totally clear stub, we'll patch it after the first execution. |
| , repatchCount(0) |
| , numberOfCoolDowns(0) |
| , bufferingCountdown(Options::repatchBufferingCountdown()) |
| , resetByGC(false) |
| , tookSlowPath(false) |
| , everConsidered(false) |
| , prototypeIsKnownObject(false) |
| , sawNonCell(false) |
| { |
| } |
| |
| StructureStubInfo::~StructureStubInfo() |
| { |
| } |
| |
| void StructureStubInfo::initGetByIdSelf(CodeBlock* codeBlock, Structure* baseObjectStructure, PropertyOffset offset) |
| { |
| cacheType = CacheType::GetByIdSelf; |
| |
| u.byIdSelf.baseObjectStructure.set( |
| codeBlock->vm(), codeBlock, baseObjectStructure); |
| u.byIdSelf.offset = offset; |
| } |
| |
| void StructureStubInfo::initArrayLength() |
| { |
| cacheType = CacheType::ArrayLength; |
| } |
| |
| void StructureStubInfo::initStringLength() |
| { |
| cacheType = CacheType::StringLength; |
| } |
| |
| void StructureStubInfo::initPutByIdReplace(CodeBlock* codeBlock, Structure* baseObjectStructure, PropertyOffset offset) |
| { |
| cacheType = CacheType::PutByIdReplace; |
| |
| u.byIdSelf.baseObjectStructure.set( |
| codeBlock->vm(), codeBlock, baseObjectStructure); |
| u.byIdSelf.offset = offset; |
| } |
| |
| void StructureStubInfo::initInByIdSelf(CodeBlock* codeBlock, Structure* baseObjectStructure, PropertyOffset offset) |
| { |
| cacheType = CacheType::InByIdSelf; |
| |
| u.byIdSelf.baseObjectStructure.set( |
| codeBlock->vm(), codeBlock, baseObjectStructure); |
| u.byIdSelf.offset = offset; |
| } |
| |
| void StructureStubInfo::deref() |
| { |
| switch (cacheType) { |
| case CacheType::Stub: |
| delete u.stub; |
| return; |
| case CacheType::Unset: |
| case CacheType::GetByIdSelf: |
| case CacheType::PutByIdReplace: |
| case CacheType::InByIdSelf: |
| case CacheType::ArrayLength: |
| case CacheType::StringLength: |
| return; |
| } |
| |
| RELEASE_ASSERT_NOT_REACHED(); |
| } |
| |
| void StructureStubInfo::aboutToDie() |
| { |
| switch (cacheType) { |
| case CacheType::Stub: |
| u.stub->aboutToDie(); |
| return; |
| case CacheType::Unset: |
| case CacheType::GetByIdSelf: |
| case CacheType::PutByIdReplace: |
| case CacheType::InByIdSelf: |
| case CacheType::ArrayLength: |
| case CacheType::StringLength: |
| return; |
| } |
| |
| RELEASE_ASSERT_NOT_REACHED(); |
| } |
| |
| AccessGenerationResult StructureStubInfo::addAccessCase( |
| const GCSafeConcurrentJSLocker& locker, CodeBlock* codeBlock, const Identifier& ident, std::unique_ptr<AccessCase> accessCase) |
| { |
| VM& vm = codeBlock->vm(); |
| ASSERT(vm.heap.isDeferred()); |
| AccessGenerationResult result = ([&] () -> AccessGenerationResult { |
| if (StructureStubInfoInternal::verbose) |
| dataLog("Adding access case: ", accessCase, "\n"); |
| |
| if (!accessCase) |
| return AccessGenerationResult::GaveUp; |
| |
| AccessGenerationResult result; |
| |
| if (cacheType == CacheType::Stub) { |
| result = u.stub->addCase(locker, vm, codeBlock, *this, ident, WTFMove(accessCase)); |
| |
| if (StructureStubInfoInternal::verbose) |
| dataLog("Had stub, result: ", result, "\n"); |
| |
| if (result.shouldResetStubAndFireWatchpoints()) |
| return result; |
| |
| if (!result.buffered()) { |
| bufferedStructures.clear(); |
| return result; |
| } |
| } else { |
| std::unique_ptr<PolymorphicAccess> access = makeUnique<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(locker, vm, codeBlock, *this, ident, WTFMove(accessCases)); |
| |
| if (StructureStubInfoInternal::verbose) |
| dataLog("Created stub, result: ", result, "\n"); |
| |
| if (result.shouldResetStubAndFireWatchpoints()) |
| return result; |
| |
| if (!result.buffered()) { |
| bufferedStructures.clear(); |
| return result; |
| } |
| |
| cacheType = CacheType::Stub; |
| u.stub = access.release(); |
| } |
| |
| 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 (StructureStubInfoInternal::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 (StructureStubInfoInternal::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(locker, vm, codeBlock, *this, ident); |
| |
| if (StructureStubInfoInternal::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; |
| })(); |
| vm.heap.writeBarrier(codeBlock); |
| return result; |
| } |
| |
| void StructureStubInfo::reset(CodeBlock* codeBlock) |
| { |
| bufferedStructures.clear(); |
| |
| if (cacheType == CacheType::Unset) |
| return; |
| |
| if (Options::verboseOSR()) { |
| // This can be called from GC destructor calls, so we don't try to do a full dump |
| // of the CodeBlock. |
| dataLog("Clearing structure cache (kind ", static_cast<int>(accessType), ") in ", RawPointer(codeBlock), ".\n"); |
| } |
| |
| switch (accessType) { |
| case AccessType::TryGet: |
| resetGetByID(codeBlock, *this, GetByIDKind::Try); |
| break; |
| case AccessType::Get: |
| resetGetByID(codeBlock, *this, GetByIDKind::Normal); |
| break; |
| case AccessType::GetWithThis: |
| resetGetByID(codeBlock, *this, GetByIDKind::WithThis); |
| break; |
| case AccessType::GetDirect: |
| resetGetByID(codeBlock, *this, GetByIDKind::Direct); |
| break; |
| case AccessType::Put: |
| resetPutByID(codeBlock, *this); |
| break; |
| case AccessType::In: |
| resetInByID(codeBlock, *this); |
| break; |
| case AccessType::InstanceOf: |
| resetInstanceOf(*this); |
| break; |
| } |
| |
| deref(); |
| cacheType = CacheType::Unset; |
| } |
| |
| void StructureStubInfo::visitWeakReferences(CodeBlock* codeBlock) |
| { |
| VM& vm = codeBlock->vm(); |
| |
| bufferedStructures.genericFilter( |
| [&] (Structure* structure) -> bool { |
| return vm.heap.isMarked(structure); |
| }); |
| |
| switch (cacheType) { |
| case CacheType::GetByIdSelf: |
| case CacheType::PutByIdReplace: |
| case CacheType::InByIdSelf: |
| if (vm.heap.isMarked(u.byIdSelf.baseObjectStructure.get())) |
| return; |
| break; |
| case CacheType::Stub: |
| if (u.stub->visitWeak(vm)) |
| return; |
| break; |
| default: |
| return; |
| } |
| |
| reset(codeBlock); |
| resetByGC = true; |
| } |
| |
| bool StructureStubInfo::propagateTransitions(SlotVisitor& visitor) |
| { |
| switch (cacheType) { |
| case CacheType::Unset: |
| case CacheType::ArrayLength: |
| case CacheType::StringLength: |
| return true; |
| case CacheType::GetByIdSelf: |
| case CacheType::PutByIdReplace: |
| case CacheType::InByIdSelf: |
| return u.byIdSelf.baseObjectStructure->markIfCheap(visitor); |
| case CacheType::Stub: |
| return u.stub->propagateTransitions(visitor); |
| } |
| |
| RELEASE_ASSERT_NOT_REACHED(); |
| return true; |
| } |
| |
| StubInfoSummary StructureStubInfo::summary() const |
| { |
| StubInfoSummary takesSlowPath = StubInfoSummary::TakesSlowPath; |
| StubInfoSummary simple = StubInfoSummary::Simple; |
| if (cacheType == CacheType::Stub) { |
| PolymorphicAccess* list = u.stub; |
| for (unsigned i = 0; i < list->size(); ++i) { |
| const AccessCase& access = list->at(i); |
| if (access.doesCalls()) { |
| takesSlowPath = StubInfoSummary::TakesSlowPathAndMakesCalls; |
| simple = StubInfoSummary::MakesCalls; |
| break; |
| } |
| } |
| } |
| |
| if (tookSlowPath || sawNonCell) |
| return takesSlowPath; |
| |
| if (!everConsidered) |
| return StubInfoSummary::NoInformation; |
| |
| return simple; |
| } |
| |
| StubInfoSummary StructureStubInfo::summary(const StructureStubInfo* stubInfo) |
| { |
| if (!stubInfo) |
| return StubInfoSummary::NoInformation; |
| |
| return stubInfo->summary(); |
| } |
| |
| bool StructureStubInfo::containsPC(void* pc) const |
| { |
| if (cacheType != CacheType::Stub) |
| return false; |
| return u.stub->containsPC(pc); |
| } |
| |
| #endif // ENABLE(JIT) |
| |
| } // namespace JSC |
