| /* |
| * Copyright (C) 2012-2015 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 "GetByIdStatus.h" |
| |
| #include "CodeBlock.h" |
| #include "ComplexGetStatus.h" |
| #include "JSCInlines.h" |
| #include "JSScope.h" |
| #include "LLIntData.h" |
| #include "LowLevelInterpreter.h" |
| #include "PolymorphicAccess.h" |
| #include <wtf/ListDump.h> |
| |
| namespace JSC { |
| |
| bool GetByIdStatus::appendVariant(const GetByIdVariant& variant) |
| { |
| // Attempt to merge this variant with an already existing variant. |
| for (unsigned i = 0; i < m_variants.size(); ++i) { |
| if (m_variants[i].attemptToMerge(variant)) |
| return true; |
| } |
| |
| // Make sure there is no overlap. We should have pruned out opportunities for |
| // overlap but it's possible that an inline cache got into a weird state. We are |
| // defensive and bail if we detect crazy. |
| for (unsigned i = 0; i < m_variants.size(); ++i) { |
| if (m_variants[i].structureSet().overlaps(variant.structureSet())) |
| return false; |
| } |
| |
| m_variants.append(variant); |
| return true; |
| } |
| |
| #if ENABLE(DFG_JIT) |
| bool GetByIdStatus::hasExitSite(const ConcurrentJITLocker& locker, CodeBlock* profiledBlock, unsigned bytecodeIndex) |
| { |
| return profiledBlock->hasExitSite(locker, DFG::FrequentExitSite(bytecodeIndex, BadCache)) |
| || profiledBlock->hasExitSite(locker, DFG::FrequentExitSite(bytecodeIndex, BadConstantCache)); |
| } |
| #endif |
| |
| GetByIdStatus GetByIdStatus::computeFromLLInt(CodeBlock* profiledBlock, unsigned bytecodeIndex, UniquedStringImpl* uid) |
| { |
| UNUSED_PARAM(profiledBlock); |
| UNUSED_PARAM(bytecodeIndex); |
| UNUSED_PARAM(uid); |
| |
| VM& vm = *profiledBlock->vm(); |
| |
| Instruction* instruction = profiledBlock->instructions().begin() + bytecodeIndex; |
| |
| if (instruction[0].u.opcode == LLInt::getOpcode(op_get_array_length)) |
| return GetByIdStatus(NoInformation, false); |
| |
| StructureID structureID = instruction[4].u.structureID; |
| if (!structureID) |
| return GetByIdStatus(NoInformation, false); |
| |
| Structure* structure = vm.heap.structureIDTable().get(structureID); |
| |
| if (structure->takesSlowPathInDFGForImpureProperty()) |
| return GetByIdStatus(NoInformation, false); |
| |
| unsigned attributesIgnored; |
| PropertyOffset offset = structure->getConcurrently(uid, attributesIgnored); |
| if (!isValidOffset(offset)) |
| return GetByIdStatus(NoInformation, false); |
| |
| return GetByIdStatus(Simple, false, GetByIdVariant(StructureSet(structure), offset)); |
| } |
| |
| GetByIdStatus GetByIdStatus::computeFor(CodeBlock* profiledBlock, StubInfoMap& map, unsigned bytecodeIndex, UniquedStringImpl* uid) |
| { |
| ConcurrentJITLocker locker(profiledBlock->m_lock); |
| |
| GetByIdStatus result; |
| |
| #if ENABLE(DFG_JIT) |
| result = computeForStubInfoWithoutExitSiteFeedback( |
| locker, profiledBlock, map.get(CodeOrigin(bytecodeIndex)), uid, |
| CallLinkStatus::computeExitSiteData(locker, profiledBlock, bytecodeIndex)); |
| |
| if (!result.takesSlowPath() |
| && hasExitSite(locker, profiledBlock, bytecodeIndex)) |
| return GetByIdStatus(result.makesCalls() ? MakesCalls : TakesSlowPath, true); |
| #else |
| UNUSED_PARAM(map); |
| #endif |
| |
| if (!result) |
| return computeFromLLInt(profiledBlock, bytecodeIndex, uid); |
| |
| return result; |
| } |
| |
| #if ENABLE(JIT) |
| GetByIdStatus GetByIdStatus::computeForStubInfo(const ConcurrentJITLocker& locker, CodeBlock* profiledBlock, StructureStubInfo* stubInfo, CodeOrigin codeOrigin, UniquedStringImpl* uid) |
| { |
| GetByIdStatus result = GetByIdStatus::computeForStubInfoWithoutExitSiteFeedback( |
| locker, profiledBlock, stubInfo, uid, |
| CallLinkStatus::computeExitSiteData(locker, profiledBlock, codeOrigin.bytecodeIndex)); |
| |
| if (!result.takesSlowPath() && GetByIdStatus::hasExitSite(locker, profiledBlock, codeOrigin.bytecodeIndex)) |
| return GetByIdStatus(result.makesCalls() ? GetByIdStatus::MakesCalls : GetByIdStatus::TakesSlowPath, true); |
| return result; |
| } |
| #endif // ENABLE(JIT) |
| |
| #if ENABLE(JIT) |
| GetByIdStatus GetByIdStatus::computeForStubInfoWithoutExitSiteFeedback( |
| const ConcurrentJITLocker& locker, CodeBlock* profiledBlock, StructureStubInfo* stubInfo, UniquedStringImpl* uid, |
| CallLinkStatus::ExitSiteData callExitSiteData) |
| { |
| if (!stubInfo) |
| return GetByIdStatus(NoInformation); |
| |
| if (!stubInfo->seen) |
| return GetByIdStatus(NoInformation); |
| |
| PolymorphicAccess* list = 0; |
| State slowPathState = TakesSlowPath; |
| if (stubInfo->cacheType == CacheType::Stub) { |
| list = stubInfo->u.stub; |
| for (unsigned i = 0; i < list->size(); ++i) { |
| const AccessCase& access = list->at(i); |
| if (access.doesCalls()) |
| slowPathState = MakesCalls; |
| } |
| } |
| |
| if (stubInfo->tookSlowPath) |
| return GetByIdStatus(slowPathState); |
| |
| // Finally figure out if we can derive an access strategy. |
| GetByIdStatus result; |
| result.m_state = Simple; |
| result.m_wasSeenInJIT = true; // This is interesting for bytecode dumping only. |
| switch (stubInfo->cacheType) { |
| case CacheType::Unset: |
| return GetByIdStatus(NoInformation); |
| |
| case CacheType::GetByIdSelf: { |
| Structure* structure = stubInfo->u.byIdSelf.baseObjectStructure.get(); |
| if (structure->takesSlowPathInDFGForImpureProperty()) |
| return GetByIdStatus(slowPathState, true); |
| unsigned attributesIgnored; |
| GetByIdVariant variant; |
| variant.m_offset = structure->getConcurrently(uid, attributesIgnored); |
| if (!isValidOffset(variant.m_offset)) |
| return GetByIdStatus(slowPathState, true); |
| |
| variant.m_structureSet.add(structure); |
| bool didAppend = result.appendVariant(variant); |
| ASSERT_UNUSED(didAppend, didAppend); |
| return result; |
| } |
| |
| case CacheType::Stub: { |
| for (unsigned listIndex = 0; listIndex < list->size(); ++listIndex) { |
| const AccessCase& access = list->at(listIndex); |
| if (access.viaProxy()) |
| return GetByIdStatus(slowPathState, true); |
| |
| Structure* structure = access.structure(); |
| if (!structure) { |
| // The null structure cases arise due to array.length and string.length. We have no way |
| // of creating a GetByIdVariant for those, and we don't really have to since the DFG |
| // handles those cases in FixupPhase using value profiling. That's a bit awkward - we |
| // shouldn't have to use value profiling to discover something that the AccessCase |
| // could have told us. But, it works well enough. So, our only concern here is to not |
| // crash on null structure. |
| return GetByIdStatus(slowPathState, true); |
| } |
| |
| ComplexGetStatus complexGetStatus = ComplexGetStatus::computeFor( |
| structure, access.conditionSet(), uid); |
| |
| switch (complexGetStatus.kind()) { |
| case ComplexGetStatus::ShouldSkip: |
| continue; |
| |
| case ComplexGetStatus::TakesSlowPath: |
| return GetByIdStatus(slowPathState, true); |
| |
| case ComplexGetStatus::Inlineable: { |
| std::unique_ptr<CallLinkStatus> callLinkStatus; |
| switch (access.type()) { |
| case AccessCase::Load: { |
| break; |
| } |
| case AccessCase::Getter: { |
| CallLinkInfo* callLinkInfo = access.callLinkInfo(); |
| ASSERT(callLinkInfo); |
| callLinkStatus = std::make_unique<CallLinkStatus>( |
| CallLinkStatus::computeFor( |
| locker, profiledBlock, *callLinkInfo, callExitSiteData)); |
| break; |
| } |
| default: { |
| // FIXME: It would be totally sweet to support more of these at some point in the |
| // future. https://bugs.webkit.org/show_bug.cgi?id=133052 |
| return GetByIdStatus(slowPathState, true); |
| } } |
| |
| GetByIdVariant variant( |
| StructureSet(structure), complexGetStatus.offset(), |
| complexGetStatus.conditionSet(), WTF::move(callLinkStatus)); |
| |
| if (!result.appendVariant(variant)) |
| return GetByIdStatus(slowPathState, true); |
| break; |
| } } |
| } |
| |
| return result; |
| } |
| |
| default: |
| return GetByIdStatus(slowPathState, true); |
| } |
| |
| RELEASE_ASSERT_NOT_REACHED(); |
| return GetByIdStatus(); |
| } |
| #endif // ENABLE(JIT) |
| |
| GetByIdStatus GetByIdStatus::computeFor( |
| CodeBlock* profiledBlock, CodeBlock* dfgBlock, StubInfoMap& baselineMap, |
| StubInfoMap& dfgMap, CodeOrigin codeOrigin, UniquedStringImpl* uid) |
| { |
| #if ENABLE(DFG_JIT) |
| if (dfgBlock) { |
| CallLinkStatus::ExitSiteData exitSiteData; |
| { |
| ConcurrentJITLocker locker(profiledBlock->m_lock); |
| exitSiteData = CallLinkStatus::computeExitSiteData( |
| locker, profiledBlock, codeOrigin.bytecodeIndex); |
| } |
| |
| GetByIdStatus result; |
| { |
| ConcurrentJITLocker locker(dfgBlock->m_lock); |
| result = computeForStubInfoWithoutExitSiteFeedback( |
| locker, dfgBlock, dfgMap.get(codeOrigin), uid, exitSiteData); |
| } |
| |
| if (result.takesSlowPath()) |
| return result; |
| |
| { |
| ConcurrentJITLocker locker(profiledBlock->m_lock); |
| if (hasExitSite(locker, profiledBlock, codeOrigin.bytecodeIndex)) |
| return GetByIdStatus(TakesSlowPath, true); |
| } |
| |
| if (result.isSet()) |
| return result; |
| } |
| #else |
| UNUSED_PARAM(dfgBlock); |
| UNUSED_PARAM(dfgMap); |
| #endif |
| |
| return computeFor(profiledBlock, baselineMap, codeOrigin.bytecodeIndex, uid); |
| } |
| |
| GetByIdStatus GetByIdStatus::computeFor(const StructureSet& set, UniquedStringImpl* uid) |
| { |
| // For now we only handle the super simple self access case. We could handle the |
| // prototype case in the future. |
| |
| if (set.isEmpty()) |
| return GetByIdStatus(); |
| |
| if (parseIndex(*uid)) |
| return GetByIdStatus(TakesSlowPath); |
| |
| GetByIdStatus result; |
| result.m_state = Simple; |
| result.m_wasSeenInJIT = false; |
| for (unsigned i = 0; i < set.size(); ++i) { |
| Structure* structure = set[i]; |
| if (structure->typeInfo().overridesGetOwnPropertySlot() && structure->typeInfo().type() != GlobalObjectType) |
| return GetByIdStatus(TakesSlowPath); |
| |
| if (!structure->propertyAccessesAreCacheable()) |
| return GetByIdStatus(TakesSlowPath); |
| |
| unsigned attributes; |
| PropertyOffset offset = structure->getConcurrently(uid, attributes); |
| if (!isValidOffset(offset)) |
| return GetByIdStatus(TakesSlowPath); // It's probably a prototype lookup. Give up on life for now, even though we could totally be way smarter about it. |
| if (attributes & Accessor) |
| return GetByIdStatus(MakesCalls); // We could be smarter here, like strenght-reducing this to a Call. |
| |
| if (!result.appendVariant(GetByIdVariant(structure, offset))) |
| return GetByIdStatus(TakesSlowPath); |
| } |
| |
| return result; |
| } |
| |
| bool GetByIdStatus::makesCalls() const |
| { |
| switch (m_state) { |
| case NoInformation: |
| case TakesSlowPath: |
| return false; |
| case Simple: |
| for (unsigned i = m_variants.size(); i--;) { |
| if (m_variants[i].callLinkStatus()) |
| return true; |
| } |
| return false; |
| case MakesCalls: |
| return true; |
| } |
| RELEASE_ASSERT_NOT_REACHED(); |
| |
| return false; |
| } |
| |
| void GetByIdStatus::dump(PrintStream& out) const |
| { |
| out.print("("); |
| switch (m_state) { |
| case NoInformation: |
| out.print("NoInformation"); |
| break; |
| case Simple: |
| out.print("Simple"); |
| break; |
| case TakesSlowPath: |
| out.print("TakesSlowPath"); |
| break; |
| case MakesCalls: |
| out.print("MakesCalls"); |
| break; |
| } |
| out.print(", ", listDump(m_variants), ", seenInJIT = ", m_wasSeenInJIT, ")"); |
| } |
| |
| } // namespace JSC |
| |
