webkitgtk-2.16.5HEADwebkitgtk-2.16.5master

1 files changed, 748 insertions, 1347 deletions

diff --git a/Source/JavaScriptCore/jit/Repatch.cpp b/Source/JavaScriptCore/jit/Repatch.cpp
index 9c31722e8..bab11b696 100644
--- a/Source/JavaScriptCore/jit/Repatch.cpp
+++ b/Source/JavaScriptCore/jit/Repatch.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2011, 2012, 2013 Apple Inc. All rights reserved.
+ * Copyright (C) 2011-2016 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -28,55 +28,60 @@
 
 #if ENABLE(JIT)
 
+#include "BinarySwitch.h"
 #include "CCallHelpers.h"
-#include "CallFrameInlines.h"
+#include "CallFrameShuffler.h"
 #include "DFGOperations.h"
 #include "DFGSpeculativeJIT.h"
+#include "DOMJITGetterSetter.h"
+#include "DirectArguments.h"
 #include "FTLThunks.h"
+#include "FunctionCodeBlock.h"
 #include "GCAwareJITStubRoutine.h"
+#include "GetterSetter.h"
+#include "GetterSetterAccessCase.h"
+#include "ICStats.h"
+#include "InlineAccess.h"
+#include "IntrinsicGetterAccessCase.h"
+#include "JIT.h"
+#include "JITInlines.h"
+#include "JSCInlines.h"
+#include "JSModuleNamespaceObject.h"
+#include "JSWebAssembly.h"
 #include "LinkBuffer.h"
-#include "Operations.h"
-#include "PolymorphicPutByIdList.h"
-#include "RepatchBuffer.h"
+#include "ModuleNamespaceAccessCase.h"
+#include "PolymorphicAccess.h"
+#include "ScopedArguments.h"
 #include "ScratchRegisterAllocator.h"
 #include "StackAlignment.h"
 #include "StructureRareDataInlines.h"
 #include "StructureStubClearingWatchpoint.h"
+#include "StructureStubInfo.h"
 #include "ThunkGenerators.h"
+#include <wtf/CommaPrinter.h>
+#include <wtf/ListDump.h>
 #include <wtf/StringPrintStream.h>
 
 namespace JSC {
 
-// Beware: in this code, it is not safe to assume anything about the following registers
-// that would ordinarily have well-known values:
-// - tagTypeNumberRegister
-// - tagMaskRegister
-// - callFrameRegister **
-//
-// We currently only use the callFrameRegister for closure call patching, and we're not going to
-// give the FTL closure call patching support until we switch to the C stack - but when we do that,
-// callFrameRegister will disappear.
-
-static FunctionPtr readCallTarget(RepatchBuffer& repatchBuffer, CodeLocationCall call)
+static FunctionPtr readCallTarget(CodeBlock* codeBlock, CodeLocationCall call)
 {
     FunctionPtr result = MacroAssembler::readCallTarget(call);
 #if ENABLE(FTL_JIT)
-    CodeBlock* codeBlock = repatchBuffer.codeBlock();
     if (codeBlock->jitType() == JITCode::FTLJIT) {
         return FunctionPtr(codeBlock->vm()->ftlThunks->keyForSlowPathCallThunk(
             MacroAssemblerCodePtr::createFromExecutableAddress(
                 result.executableAddress())).callTarget());
     }
 #else
-    UNUSED_PARAM(repatchBuffer);
+    UNUSED_PARAM(codeBlock);
 #endif // ENABLE(FTL_JIT)
     return result;
 }
 
-static void repatchCall(RepatchBuffer& repatchBuffer, CodeLocationCall call, FunctionPtr newCalleeFunction)
+void ftlThunkAwareRepatchCall(CodeBlock* codeBlock, CodeLocationCall call, FunctionPtr newCalleeFunction)
 {
 #if ENABLE(FTL_JIT)
-    CodeBlock* codeBlock = repatchBuffer.codeBlock();
     if (codeBlock->jitType() == JITCode::FTLJIT) {
         VM& vm = *codeBlock->vm();
         FTL::Thunks& thunks = *vm.ftlThunks;
@@ -87,655 +92,247 @@ static void repatchCall(RepatchBuffer& repatchBuffer, CodeLocationCall call, Fun
         newCalleeFunction = FunctionPtr(
             thunks.getSlowPathCallThunk(vm, key).code().executableAddress());
     }
+#else // ENABLE(FTL_JIT)
+    UNUSED_PARAM(codeBlock);
 #endif // ENABLE(FTL_JIT)
-    repatchBuffer.relink(call, newCalleeFunction);
+    MacroAssembler::repatchCall(call, newCalleeFunction);
 }
 
-static void repatchCall(CodeBlock* codeblock, CodeLocationCall call, FunctionPtr newCalleeFunction)
-{
-    RepatchBuffer repatchBuffer(codeblock);
-    repatchCall(repatchBuffer, call, newCalleeFunction);
-}
+enum InlineCacheAction {
+    GiveUpOnCache,
+    RetryCacheLater,
+    AttemptToCache
+};
 
-static void repatchByIdSelfAccess(VM& vm, CodeBlock* codeBlock, StructureStubInfo& stubInfo, Structure* structure, const Identifier& propertyName, PropertyOffset offset,
-    const FunctionPtr &slowPathFunction, bool compact)
+static InlineCacheAction actionForCell(VM& vm, JSCell* cell)
 {
-    if (structure->typeInfo().newImpurePropertyFiresWatchpoints())
-        vm.registerWatchpointForImpureProperty(propertyName, stubInfo.addWatchpoint(codeBlock));
-
-    RepatchBuffer repatchBuffer(codeBlock);
+    Structure* structure = cell->structure(vm);
 
-    // Only optimize once!
-    repatchCall(repatchBuffer, stubInfo.callReturnLocation, slowPathFunction);
+    TypeInfo typeInfo = structure->typeInfo();
+    if (typeInfo.prohibitsPropertyCaching())
+        return GiveUpOnCache;
 
-    // Patch the structure check & the offset of the load.
-    repatchBuffer.repatch(stubInfo.callReturnLocation.dataLabelPtrAtOffset(-(intptr_t)stubInfo.patch.deltaCheckImmToCall), structure);
-    repatchBuffer.setLoadInstructionIsActive(stubInfo.callReturnLocation.convertibleLoadAtOffset(stubInfo.patch.deltaCallToStorageLoad), isOutOfLineOffset(offset));
-#if USE(JSVALUE64)
-    if (compact)
-        repatchBuffer.repatch(stubInfo.callReturnLocation.dataLabelCompactAtOffset(stubInfo.patch.deltaCallToLoadOrStore), offsetRelativeToPatchedStorage(offset));
-    else
-        repatchBuffer.repatch(stubInfo.callReturnLocation.dataLabel32AtOffset(stubInfo.patch.deltaCallToLoadOrStore), offsetRelativeToPatchedStorage(offset));
-#elif USE(JSVALUE32_64)
-    if (compact) {
-        repatchBuffer.repatch(stubInfo.callReturnLocation.dataLabelCompactAtOffset(stubInfo.patch.deltaCallToTagLoadOrStore), offsetRelativeToPatchedStorage(offset) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.tag));
-        repatchBuffer.repatch(stubInfo.callReturnLocation.dataLabelCompactAtOffset(stubInfo.patch.deltaCallToPayloadLoadOrStore), offsetRelativeToPatchedStorage(offset) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.payload));
-    } else {
-        repatchBuffer.repatch(stubInfo.callReturnLocation.dataLabel32AtOffset(stubInfo.patch.deltaCallToTagLoadOrStore), offsetRelativeToPatchedStorage(offset) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.tag));
-        repatchBuffer.repatch(stubInfo.callReturnLocation.dataLabel32AtOffset(stubInfo.patch.deltaCallToPayloadLoadOrStore), offsetRelativeToPatchedStorage(offset) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.payload));
-    }
-#endif
-}
-
-static void addStructureTransitionCheck(
-    JSCell* object, Structure* structure, CodeBlock* codeBlock, StructureStubInfo& stubInfo,
-    MacroAssembler& jit, MacroAssembler::JumpList& failureCases, GPRReg scratchGPR)
-{
-    if (object->structure() == structure && structure->transitionWatchpointSetIsStillValid()) {
-        structure->addTransitionWatchpoint(stubInfo.addWatchpoint(codeBlock));
-#if !ASSERT_DISABLED
-        // If we execute this code, the object must have the structure we expect. Assert
-        // this in debug modes.
-        jit.move(MacroAssembler::TrustedImmPtr(object), scratchGPR);
-        MacroAssembler::Jump ok = jit.branchPtr(
-            MacroAssembler::Equal,
-            MacroAssembler::Address(scratchGPR, JSCell::structureOffset()),
-            MacroAssembler::TrustedImmPtr(structure));
-        jit.breakpoint();
-        ok.link(&jit);
-#endif
-        return;
+    if (structure->isUncacheableDictionary()) {
+        if (structure->hasBeenFlattenedBefore())
+            return GiveUpOnCache;
+        // Flattening could have changed the offset, so return early for another try.
+        asObject(cell)->flattenDictionaryObject(vm);
+        return RetryCacheLater;
     }
     
-    jit.move(MacroAssembler::TrustedImmPtr(object), scratchGPR);
-    failureCases.append(
-        jit.branchPtr(
-            MacroAssembler::NotEqual,
-            MacroAssembler::Address(scratchGPR, JSCell::structureOffset()),
-            MacroAssembler::TrustedImmPtr(structure)));
-}
-
-static void addStructureTransitionCheck(
-    JSValue prototype, CodeBlock* codeBlock, StructureStubInfo& stubInfo,
-    MacroAssembler& jit, MacroAssembler::JumpList& failureCases, GPRReg scratchGPR)
-{
-    if (prototype.isNull())
-        return;
-    
-    ASSERT(prototype.isCell());
-    
-    addStructureTransitionCheck(
-        prototype.asCell(), prototype.asCell()->structure(), codeBlock, stubInfo, jit,
-        failureCases, scratchGPR);
-}
+    if (!structure->propertyAccessesAreCacheable())
+        return GiveUpOnCache;
 
-static void replaceWithJump(RepatchBuffer& repatchBuffer, StructureStubInfo& stubInfo, const MacroAssemblerCodePtr target)
-{
-    if (MacroAssembler::canJumpReplacePatchableBranchPtrWithPatch()) {
-        repatchBuffer.replaceWithJump(
-            RepatchBuffer::startOfPatchableBranchPtrWithPatchOnAddress(
-                stubInfo.callReturnLocation.dataLabelPtrAtOffset(
-                    -(intptr_t)stubInfo.patch.deltaCheckImmToCall)),
-            CodeLocationLabel(target));
-        return;
-    }
-    
-    repatchBuffer.relink(
-        stubInfo.callReturnLocation.jumpAtOffset(
-            stubInfo.patch.deltaCallToJump),
-        CodeLocationLabel(target));
+    return AttemptToCache;
 }
 
-static void emitRestoreScratch(MacroAssembler& stubJit, bool needToRestoreScratch, GPRReg scratchGPR, MacroAssembler::Jump& success, MacroAssembler::Jump& fail, MacroAssembler::JumpList failureCases)
+static bool forceICFailure(ExecState*)
 {
-    if (needToRestoreScratch) {
-        stubJit.popToRestore(scratchGPR);
-        
-        success = stubJit.jump();
-        
-        // link failure cases here, so we can pop scratchGPR, and then jump back.
-        failureCases.link(&stubJit);
-        
-        stubJit.popToRestore(scratchGPR);
-        
-        fail = stubJit.jump();
-        return;
-    }
-    
-    success = stubJit.jump();
+#if CPU(ARM_TRADITIONAL)
+    // FIXME: Remove this workaround once the proper fixes are landed.
+    // [ARM] Disable Inline Caching on ARMv7 traditional until proper fix
+    // https://bugs.webkit.org/show_bug.cgi?id=159759
+    return true;
+#else
+    return Options::forceICFailure();
+#endif
 }
 
-static void linkRestoreScratch(LinkBuffer& patchBuffer, bool needToRestoreScratch, MacroAssembler::Jump success, MacroAssembler::Jump fail, MacroAssembler::JumpList failureCases, CodeLocationLabel successLabel, CodeLocationLabel slowCaseBegin)
+inline J_JITOperation_ESsiJI appropriateOptimizingGetByIdFunction(GetByIDKind kind)
 {
-    patchBuffer.link(success, successLabel);
-        
-    if (needToRestoreScratch) {
-        patchBuffer.link(fail, slowCaseBegin);
-        return;
-    }
-    
-    // link failure cases directly back to normal path
-    patchBuffer.link(failureCases, slowCaseBegin);
+    if (kind == GetByIDKind::Normal)
+        return operationGetByIdOptimize;
+    return operationTryGetByIdOptimize;
 }
 
-static void linkRestoreScratch(LinkBuffer& patchBuffer, bool needToRestoreScratch, StructureStubInfo& stubInfo, MacroAssembler::Jump success, MacroAssembler::Jump fail, MacroAssembler::JumpList failureCases)
+inline J_JITOperation_ESsiJI appropriateGenericGetByIdFunction(GetByIDKind kind)
 {
-    linkRestoreScratch(patchBuffer, needToRestoreScratch, success, fail, failureCases, stubInfo.callReturnLocation.labelAtOffset(stubInfo.patch.deltaCallToDone), stubInfo.callReturnLocation.labelAtOffset(stubInfo.patch.deltaCallToSlowCase));
+    if (kind == GetByIDKind::Normal)
+        return operationGetById;
+    return operationTryGetById;
 }
 
-enum ProtoChainGenerationResult {
-    ProtoChainGenerationFailed,
-    ProtoChainGenerationSucceeded
-};
-
-static ProtoChainGenerationResult generateProtoChainAccessStub(ExecState*, const PropertySlot&, const Identifier&, StructureStubInfo&, StructureChain*, size_t, PropertyOffset, Structure*, CodeLocationLabel, CodeLocationLabel, RefPtr<JITStubRoutine>&) WARN_UNUSED_RETURN;
-static ProtoChainGenerationResult generateProtoChainAccessStub(ExecState* exec, const PropertySlot& slot, const Identifier& propertyName, StructureStubInfo& stubInfo, StructureChain* chain, size_t count, PropertyOffset offset, Structure* structure, CodeLocationLabel successLabel, CodeLocationLabel slowCaseLabel, RefPtr<JITStubRoutine>& stubRoutine)
+static InlineCacheAction tryCacheGetByID(ExecState* exec, JSValue baseValue, const Identifier& propertyName, const PropertySlot& slot, StructureStubInfo& stubInfo, GetByIDKind kind)
 {
-    VM* vm = &exec->vm();
-    GPRReg baseGPR = static_cast<GPRReg>(stubInfo.patch.baseGPR);
-#if USE(JSVALUE32_64)
-    GPRReg resultTagGPR = static_cast<GPRReg>(stubInfo.patch.valueTagGPR);
-#endif
-    GPRReg resultGPR = static_cast<GPRReg>(stubInfo.patch.valueGPR);
-    GPRReg scratchGPR = TempRegisterSet(stubInfo.patch.usedRegisters).getFreeGPR();
-    bool needToRestoreScratch = scratchGPR == InvalidGPRReg;
-    if (needToRestoreScratch && !slot.isCacheableValue())
-        return ProtoChainGenerationFailed;
+    if (forceICFailure(exec))
+        return GiveUpOnCache;
     
-    CCallHelpers stubJit(&exec->vm(), exec->codeBlock());
-    if (needToRestoreScratch) {
-#if USE(JSVALUE64)
-        scratchGPR = AssemblyHelpers::selectScratchGPR(baseGPR, resultGPR);
-#else
-        scratchGPR = AssemblyHelpers::selectScratchGPR(baseGPR, resultGPR, resultTagGPR);
-#endif
-        stubJit.pushToSave(scratchGPR);
-        needToRestoreScratch = true;
-    }
-    
-    MacroAssembler::JumpList failureCases;
-    
-    failureCases.append(stubJit.branchPtr(MacroAssembler::NotEqual, MacroAssembler::Address(baseGPR, JSCell::structureOffset()), MacroAssembler::TrustedImmPtr(structure)));
+    // FIXME: Cache property access for immediates.
+    if (!baseValue.isCell())
+        return GiveUpOnCache;
 
     CodeBlock* codeBlock = exec->codeBlock();
-    if (structure->typeInfo().newImpurePropertyFiresWatchpoints())
-        vm->registerWatchpointForImpureProperty(propertyName, stubInfo.addWatchpoint(codeBlock));
-
-    Structure* currStructure = structure;
-    WriteBarrier<Structure>* it = chain->head();
-    JSObject* protoObject = 0;
-    for (unsigned i = 0; i < count; ++i, ++it) {
-        protoObject = asObject(currStructure->prototypeForLookup(exec));
-        Structure* protoStructure = protoObject->structure();
-        if (protoStructure->typeInfo().newImpurePropertyFiresWatchpoints())
-            vm->registerWatchpointForImpureProperty(propertyName, stubInfo.addWatchpoint(codeBlock));
-        addStructureTransitionCheck(
-            protoObject, protoStructure, codeBlock, stubInfo, stubJit,
-            failureCases, scratchGPR);
-        currStructure = it->get();
-    }
-    
-    bool isAccessor = slot.isCacheableGetter() || slot.isCacheableCustom();
-    if (isAccessor)
-        stubJit.move(baseGPR, scratchGPR);
+    VM& vm = exec->vm();
 
-    if (!slot.isCacheableCustom()) {
-        if (isInlineOffset(offset)) {
-#if USE(JSVALUE64)
-            stubJit.load64(protoObject->locationForOffset(offset), resultGPR);
-#elif USE(JSVALUE32_64)
-            stubJit.move(MacroAssembler::TrustedImmPtr(protoObject->locationForOffset(offset)), resultGPR);
-            stubJit.load32(MacroAssembler::Address(resultGPR, OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.tag)), resultTagGPR);
-            stubJit.load32(MacroAssembler::Address(resultGPR, OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.payload)), resultGPR);
-#endif
-        } else {
-            stubJit.loadPtr(protoObject->butterflyAddress(), resultGPR);
-#if USE(JSVALUE64)
-            stubJit.load64(MacroAssembler::Address(resultGPR, offsetInButterfly(offset) * sizeof(WriteBarrier<Unknown>)), resultGPR);
-#elif USE(JSVALUE32_64)
-            stubJit.load32(MacroAssembler::Address(resultGPR, offsetInButterfly(offset) * sizeof(WriteBarrier<Unknown>) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.tag)), resultTagGPR);
-            stubJit.load32(MacroAssembler::Address(resultGPR, offsetInButterfly(offset) * sizeof(WriteBarrier<Unknown>) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.payload)), resultGPR);
-#endif
-        }
-    }
-    MacroAssembler::Call operationCall;
-    MacroAssembler::Call handlerCall;
-    FunctionPtr operationFunction;
-    MacroAssembler::Jump success, fail;
-    if (isAccessor) {
-        GPRReg callFrameRegister = static_cast<GPRReg>(stubInfo.patch.callFrameRegister);
-        if (slot.isCacheableGetter()) {
-            stubJit.setupArguments(callFrameRegister, scratchGPR, resultGPR);
-            operationFunction = operationCallGetter;
-        } else {
-            stubJit.move(MacroAssembler::TrustedImmPtr(protoObject), scratchGPR);
-            stubJit.setupArguments(callFrameRegister, scratchGPR,
-                MacroAssembler::TrustedImmPtr(FunctionPtr(slot.customGetter()).executableAddress()),
-                MacroAssembler::TrustedImmPtr(propertyName.impl()));
-            operationFunction = operationCallCustomGetter;
-        }
+    std::unique_ptr<AccessCase> newCase;
 
-        // Need to make sure that whenever this call is made in the future, we remember the
-        // place that we made it from. It just so happens to be the place that we are at
-        // right now!
-        stubJit.store32(MacroAssembler::TrustedImm32(exec->locationAsRawBits()),
-            CCallHelpers::tagFor(static_cast<VirtualRegister>(JSStack::ArgumentCount)));
+    if (propertyName == vm.propertyNames->length) {
+        if (isJSArray(baseValue)) {
+            if (stubInfo.cacheType == CacheType::Unset
+                && slot.slotBase() == baseValue
+                && InlineAccess::isCacheableArrayLength(stubInfo, jsCast<JSArray*>(baseValue))) {
 
-        operationCall = stubJit.call();
-#if USE(JSVALUE64)
-        stubJit.move(GPRInfo::returnValueGPR, resultGPR);
-#else
-        stubJit.setupResults(resultGPR, resultTagGPR);
-#endif
-        MacroAssembler::Jump noException = stubJit.emitExceptionCheck(CCallHelpers::InvertedExceptionCheck);
-
-        stubJit.setupArgumentsExecState();
-        handlerCall = stubJit.call();
-        stubJit.jumpToExceptionHandler();
-        
-        noException.link(&stubJit);
-    }
-    emitRestoreScratch(stubJit, needToRestoreScratch, scratchGPR, success, fail, failureCases);
-    
-    LinkBuffer patchBuffer(*vm, &stubJit, exec->codeBlock());
-    
-    linkRestoreScratch(patchBuffer, needToRestoreScratch, success, fail, failureCases, successLabel, slowCaseLabel);
-    if (isAccessor) {
-        patchBuffer.link(operationCall, operationFunction);
-        patchBuffer.link(handlerCall, lookupExceptionHandler);
-    }
-    stubRoutine = FINALIZE_CODE_FOR_DFG_STUB(
-        patchBuffer,
-        ("DFG prototype chain access stub for %s, return point %p",
-            toCString(*exec->codeBlock()).data(), successLabel.executableAddress()));
-    return ProtoChainGenerationSucceeded;
-}
-
-static bool tryCacheGetByID(ExecState* exec, JSValue baseValue, const Identifier& propertyName, const PropertySlot& slot, StructureStubInfo& stubInfo)
-{
-    // FIXME: Write a test that proves we need to check for recursion here just
-    // like the interpreter does, then add a check for recursion.
+                bool generatedCodeInline = InlineAccess::generateArrayLength(*codeBlock->vm(), stubInfo, jsCast<JSArray*>(baseValue));
+                if (generatedCodeInline) {
+                    ftlThunkAwareRepatchCall(codeBlock, stubInfo.slowPathCallLocation(), appropriateOptimizingGetByIdFunction(kind));
+                    stubInfo.initArrayLength();
+                    return RetryCacheLater;
+                }
+            }
 
-    CodeBlock* codeBlock = exec->codeBlock();
-    VM* vm = &exec->vm();
-    
-    if (isJSArray(baseValue) && propertyName == exec->propertyNames().length) {
-        GPRReg baseGPR = static_cast<GPRReg>(stubInfo.patch.baseGPR);
-#if USE(JSVALUE32_64)
-        GPRReg resultTagGPR = static_cast<GPRReg>(stubInfo.patch.valueTagGPR);
-#endif
-        GPRReg resultGPR = static_cast<GPRReg>(stubInfo.patch.valueGPR);
-        GPRReg scratchGPR = TempRegisterSet(stubInfo.patch.usedRegisters).getFreeGPR();
-        bool needToRestoreScratch = false;
-        
-        MacroAssembler stubJit;
-        
-        if (scratchGPR == InvalidGPRReg) {
-#if USE(JSVALUE64)
-            scratchGPR = AssemblyHelpers::selectScratchGPR(baseGPR, resultGPR);
-#else
-            scratchGPR = AssemblyHelpers::selectScratchGPR(baseGPR, resultGPR, resultTagGPR);
-#endif
-            stubJit.pushToSave(scratchGPR);
-            needToRestoreScratch = true;
+            newCase = AccessCase::create(vm, codeBlock, AccessCase::ArrayLength);
+        } else if (isJSString(baseValue))
+            newCase = AccessCase::create(vm, codeBlock, AccessCase::StringLength);
+        else if (DirectArguments* arguments = jsDynamicCast<DirectArguments*>(vm, baseValue)) {
+            // If there were overrides, then we can handle this as a normal property load! Guarding
+            // this with such a check enables us to add an IC case for that load if needed.
+            if (!arguments->overrodeThings())
+                newCase = AccessCase::create(vm, codeBlock, AccessCase::DirectArgumentsLength);
+        } else if (ScopedArguments* arguments = jsDynamicCast<ScopedArguments*>(vm, baseValue)) {
+            // Ditto.
+            if (!arguments->overrodeThings())
+                newCase = AccessCase::create(vm, codeBlock, AccessCase::ScopedArgumentsLength);
         }
-        
-        MacroAssembler::JumpList failureCases;
-       
-        stubJit.loadPtr(MacroAssembler::Address(baseGPR, JSCell::structureOffset()), scratchGPR); 
-        stubJit.load8(MacroAssembler::Address(scratchGPR, Structure::indexingTypeOffset()), scratchGPR);
-        failureCases.append(stubJit.branchTest32(MacroAssembler::Zero, scratchGPR, MacroAssembler::TrustedImm32(IsArray)));
-        failureCases.append(stubJit.branchTest32(MacroAssembler::Zero, scratchGPR, MacroAssembler::TrustedImm32(IndexingShapeMask)));
-        
-        stubJit.loadPtr(MacroAssembler::Address(baseGPR, JSObject::butterflyOffset()), scratchGPR);
-        stubJit.load32(MacroAssembler::Address(scratchGPR, ArrayStorage::lengthOffset()), scratchGPR);
-        failureCases.append(stubJit.branch32(MacroAssembler::LessThan, scratchGPR, MacroAssembler::TrustedImm32(0)));
-
-        stubJit.move(scratchGPR, resultGPR);
-#if USE(JSVALUE64)
-        stubJit.or64(AssemblyHelpers::TrustedImm64(TagTypeNumber), resultGPR);
-#elif USE(JSVALUE32_64)
-        stubJit.move(AssemblyHelpers::TrustedImm32(0xffffffff), resultTagGPR); // JSValue::Int32Tag
-#endif
-
-        MacroAssembler::Jump success, fail;
-        
-        emitRestoreScratch(stubJit, needToRestoreScratch, scratchGPR, success, fail, failureCases);
-        
-        LinkBuffer patchBuffer(*vm, &stubJit, codeBlock);
-        
-        linkRestoreScratch(patchBuffer, needToRestoreScratch, stubInfo, success, fail, failureCases);
-        
-        stubInfo.stubRoutine = FINALIZE_CODE_FOR_DFG_STUB(
-            patchBuffer,
-            ("DFG GetById array length stub for %s, return point %p",
-                toCString(*exec->codeBlock()).data(), stubInfo.callReturnLocation.labelAtOffset(
-                    stubInfo.patch.deltaCallToDone).executableAddress()));
-        
-        RepatchBuffer repatchBuffer(codeBlock);
-        replaceWithJump(repatchBuffer, stubInfo, stubInfo.stubRoutine->code().code());
-        repatchCall(repatchBuffer, stubInfo.callReturnLocation, operationGetById);
-        
-        return true;
     }
-    
-    // FIXME: should support length access for String.
-
-    // FIXME: Cache property access for immediates.
-    if (!baseValue.isCell())
-        return false;
-    JSCell* baseCell = baseValue.asCell();
-    Structure* structure = baseCell->structure();
-    if (!slot.isCacheable())
-        return false;
-    if (!structure->propertyAccessesAreCacheable())
-        return false;
-
-    // Optimize self access.
-    if (slot.slotBase() == baseValue) {
-        if (!slot.isCacheableValue()
-            || !MacroAssembler::isCompactPtrAlignedAddressOffset(maxOffsetRelativeToPatchedStorage(slot.cachedOffset()))) {
-            repatchCall(codeBlock, stubInfo.callReturnLocation, operationGetByIdBuildList);
-            return true;
-        }
 
-        repatchByIdSelfAccess(*vm, codeBlock, stubInfo, structure, propertyName, slot.cachedOffset(), operationGetByIdBuildList, true);
-        stubInfo.initGetByIdSelf(*vm, codeBlock->ownerExecutable(), structure);
-        return true;
+    if (!propertyName.isSymbol() && isJSModuleNamespaceObject(baseValue) && !slot.isUnset()) {
+        if (auto moduleNamespaceSlot = slot.moduleNamespaceSlot())
+            newCase = ModuleNamespaceAccessCase::create(vm, codeBlock, jsCast<JSModuleNamespaceObject*>(baseValue), moduleNamespaceSlot->environment, ScopeOffset(moduleNamespaceSlot->scopeOffset));
     }
     
-    if (structure->isDictionary())
-        return false;
-
-    if (!stubInfo.patch.registersFlushed) {
-        // We cannot do as much inline caching if the registers were not flushed prior to this GetById. In particular,
-        // non-Value cached properties require planting calls, which requires registers to have been flushed. Thus,
-        // if registers were not flushed, don't do non-Value caching.
-        if (!slot.isCacheableValue())
-            return false;
-    }
-    
-    PropertyOffset offset = slot.cachedOffset();
-    size_t count = normalizePrototypeChainForChainAccess(exec, baseValue, slot.slotBase(), propertyName, offset);
-    if (count == InvalidPrototypeChain)
-        return false;
-
-    StructureChain* prototypeChain = structure->prototypeChain(exec);
-    if (generateProtoChainAccessStub(exec, slot, propertyName, stubInfo, prototypeChain, count, offset,
-        structure, stubInfo.callReturnLocation.labelAtOffset(stubInfo.patch.deltaCallToDone),
-        stubInfo.callReturnLocation.labelAtOffset(stubInfo.patch.deltaCallToSlowCase), stubInfo.stubRoutine) == ProtoChainGenerationFailed)
-        return false;
-    
-    RepatchBuffer repatchBuffer(codeBlock);
-    replaceWithJump(repatchBuffer, stubInfo, stubInfo.stubRoutine->code().code());
-    repatchCall(repatchBuffer, stubInfo.callReturnLocation, operationGetByIdBuildList);
-    
-    stubInfo.initGetByIdChain(*vm, codeBlock->ownerExecutable(), structure, prototypeChain, count, slot.isCacheableValue());
-    return true;
-}
+    if (!newCase) {
+        if (!slot.isCacheable() && !slot.isUnset())
+            return GiveUpOnCache;
 
-void repatchGetByID(ExecState* exec, JSValue baseValue, const Identifier& propertyName, const PropertySlot& slot, StructureStubInfo& stubInfo)
-{
-    GCSafeConcurrentJITLocker locker(exec->codeBlock()->m_lock, exec->vm().heap);
-    
-    bool cached = tryCacheGetByID(exec, baseValue, propertyName, slot, stubInfo);
-    if (!cached)
-        repatchCall(exec->codeBlock(), stubInfo.callReturnLocation, operationGetById);
-}
+        ObjectPropertyConditionSet conditionSet;
+        JSCell* baseCell = baseValue.asCell();
+        Structure* structure = baseCell->structure(vm);
 
-static bool getPolymorphicStructureList(
-    VM* vm, CodeBlock* codeBlock, StructureStubInfo& stubInfo,
-    PolymorphicAccessStructureList*& polymorphicStructureList, int& listIndex,
-    CodeLocationLabel& slowCase)
-{
-    slowCase = stubInfo.callReturnLocation.labelAtOffset(stubInfo.patch.deltaCallToSlowCase);
-    
-    if (stubInfo.accessType == access_unset) {
-        RELEASE_ASSERT(!stubInfo.stubRoutine);
-        polymorphicStructureList = new PolymorphicAccessStructureList();
-        stubInfo.initGetByIdSelfList(polymorphicStructureList, 0, false);
-        listIndex = 0;
-    } else if (stubInfo.accessType == access_get_by_id_self) {
-        RELEASE_ASSERT(!stubInfo.stubRoutine);
-        polymorphicStructureList = new PolymorphicAccessStructureList(*vm, codeBlock->ownerExecutable(), JITStubRoutine::createSelfManagedRoutine(slowCase), stubInfo.u.getByIdSelf.baseObjectStructure.get(), true);
-        stubInfo.initGetByIdSelfList(polymorphicStructureList, 1, true);
-        listIndex = 1;
-    } else if (stubInfo.accessType == access_get_by_id_chain) {
-        RELEASE_ASSERT(!!stubInfo.stubRoutine);
-        slowCase = CodeLocationLabel(stubInfo.stubRoutine->code().code());
-        polymorphicStructureList = new PolymorphicAccessStructureList(*vm, codeBlock->ownerExecutable(), stubInfo.stubRoutine, stubInfo.u.getByIdChain.baseObjectStructure.get(), stubInfo.u.getByIdChain.chain.get(), true);
-        stubInfo.stubRoutine.clear();
-        stubInfo.initGetByIdSelfList(polymorphicStructureList, 1, false);
-        listIndex = 1;
-    } else {
-        RELEASE_ASSERT(stubInfo.accessType == access_get_by_id_self_list);
-        polymorphicStructureList = stubInfo.u.getByIdSelfList.structureList;
-        listIndex = stubInfo.u.getByIdSelfList.listSize;
-        slowCase = CodeLocationLabel(polymorphicStructureList->list[listIndex - 1].stubRoutine->code().code());
-    }
-    
-    if (listIndex == POLYMORPHIC_LIST_CACHE_SIZE)
-        return false;
-    
-    RELEASE_ASSERT(listIndex < POLYMORPHIC_LIST_CACHE_SIZE);
-    return true;
-}
+        bool loadTargetFromProxy = false;
+        if (baseCell->type() == PureForwardingProxyType) {
+            baseValue = jsCast<JSProxy*>(baseCell)->target();
+            baseCell = baseValue.asCell();
+            structure = baseCell->structure(vm);
+            loadTargetFromProxy = true;
+        }
 
-static void patchJumpToGetByIdStub(CodeBlock* codeBlock, StructureStubInfo& stubInfo, JITStubRoutine* stubRoutine)
-{
-    RELEASE_ASSERT(stubInfo.accessType == access_get_by_id_self_list);
-    RepatchBuffer repatchBuffer(codeBlock);
-    if (stubInfo.u.getByIdSelfList.didSelfPatching) {
-        repatchBuffer.relink(
-            stubInfo.callReturnLocation.jumpAtOffset(
-                stubInfo.patch.deltaCallToJump),
-            CodeLocationLabel(stubRoutine->code().code()));
-        return;
-    }
-    
-    replaceWithJump(repatchBuffer, stubInfo, stubRoutine->code().code());
-}
+        InlineCacheAction action = actionForCell(vm, baseCell);
+        if (action != AttemptToCache)
+            return action;
+
+        // Optimize self access.
+        if (stubInfo.cacheType == CacheType::Unset
+            && slot.isCacheableValue()
+            && slot.slotBase() == baseValue
+            && !slot.watchpointSet()
+            && !structure->needImpurePropertyWatchpoint()
+            && !loadTargetFromProxy) {
+
+            bool generatedCodeInline = InlineAccess::generateSelfPropertyAccess(*codeBlock->vm(), stubInfo, structure, slot.cachedOffset());
+            if (generatedCodeInline) {
+                LOG_IC((ICEvent::GetByIdSelfPatch, structure->classInfo(), propertyName));
+                structure->startWatchingPropertyForReplacements(vm, slot.cachedOffset());
+                ftlThunkAwareRepatchCall(codeBlock, stubInfo.slowPathCallLocation(), appropriateOptimizingGetByIdFunction(kind));
+                stubInfo.initGetByIdSelf(codeBlock, structure, slot.cachedOffset());
+                return RetryCacheLater;
+            }
+        }
 
-static bool tryBuildGetByIDList(ExecState* exec, JSValue baseValue, const Identifier& ident, const PropertySlot& slot, StructureStubInfo& stubInfo)
-{
-    if (!baseValue.isCell()
-        || !slot.isCacheable()
-        || !baseValue.asCell()->structure()->propertyAccessesAreCacheable())
-        return false;
+        PropertyOffset offset = slot.isUnset() ? invalidOffset : slot.cachedOffset();
 
-    CodeBlock* codeBlock = exec->codeBlock();
-    VM* vm = &exec->vm();
-    JSCell* baseCell = baseValue.asCell();
-    Structure* structure = baseCell->structure();
-    
-    if (slot.slotBase() == baseValue) {
-        if (!stubInfo.patch.registersFlushed) {
-            // We cannot do as much inline caching if the registers were not flushed prior to this GetById. In particular,
-            // non-Value cached properties require planting calls, which requires registers to have been flushed. Thus,
-            // if registers were not flushed, don't do non-Value caching.
-            if (!slot.isCacheableValue())
-                return false;
-        }
-    
-        PolymorphicAccessStructureList* polymorphicStructureList;
-        int listIndex;
-        CodeLocationLabel slowCase;
+        if (slot.isUnset() || slot.slotBase() != baseValue) {
+            if (structure->typeInfo().prohibitsPropertyCaching())
+                return GiveUpOnCache;
 
-        if (!getPolymorphicStructureList(vm, codeBlock, stubInfo, polymorphicStructureList, listIndex, slowCase))
-            return false;
-        
-        stubInfo.u.getByIdSelfList.listSize++;
-        
-        GPRReg callFrameRegister = static_cast<GPRReg>(stubInfo.patch.callFrameRegister);
-        GPRReg baseGPR = static_cast<GPRReg>(stubInfo.patch.baseGPR);
-#if USE(JSVALUE32_64)
-        GPRReg resultTagGPR = static_cast<GPRReg>(stubInfo.patch.valueTagGPR);
-#endif
-        GPRReg resultGPR = static_cast<GPRReg>(stubInfo.patch.valueGPR);
-        GPRReg scratchGPR = TempRegisterSet(stubInfo.patch.usedRegisters).getFreeGPR();
-        
-        CCallHelpers stubJit(vm, codeBlock);
-        
-        MacroAssembler::Jump wrongStruct = stubJit.branchPtr(MacroAssembler::NotEqual, MacroAssembler::Address(baseGPR, JSCell::structureOffset()), MacroAssembler::TrustedImmPtr(structure));
-        
-        // The strategy we use for stubs is as follows:
-        // 1) Call DFG helper that calls the getter.
-        // 2) Check if there was an exception, and if there was, call yet another
-        //    helper.
-        
-        bool isDirect = false;
-        MacroAssembler::Call operationCall;
-        MacroAssembler::Call handlerCall;
-        FunctionPtr operationFunction;
-        MacroAssembler::Jump success;
-        
-        if (slot.isCacheableGetter() || slot.isCacheableCustom()) {
-            if (slot.isCacheableGetter()) {
-                ASSERT(scratchGPR != InvalidGPRReg);
-                ASSERT(baseGPR != scratchGPR);
-                if (isInlineOffset(slot.cachedOffset())) {
-#if USE(JSVALUE64)
-                    stubJit.load64(MacroAssembler::Address(baseGPR, offsetRelativeToBase(slot.cachedOffset())), scratchGPR);
-#else
-                    stubJit.load32(MacroAssembler::Address(baseGPR, offsetRelativeToBase(slot.cachedOffset())), scratchGPR);
-#endif
-                } else {
-                    stubJit.loadPtr(MacroAssembler::Address(baseGPR, JSObject::butterflyOffset()), scratchGPR);
-#if USE(JSVALUE64)
-                    stubJit.load64(MacroAssembler::Address(scratchGPR, offsetRelativeToBase(slot.cachedOffset())), scratchGPR);
-#else
-                    stubJit.load32(MacroAssembler::Address(scratchGPR, offsetRelativeToBase(slot.cachedOffset())), scratchGPR);
-#endif
-                }
-                stubJit.setupArguments(callFrameRegister, baseGPR, scratchGPR);
-                operationFunction = operationCallGetter;
-            } else {
-                stubJit.setupArguments(
-                    callFrameRegister, baseGPR,
-                    MacroAssembler::TrustedImmPtr(FunctionPtr(slot.customGetter()).executableAddress()),
-                    MacroAssembler::TrustedImmPtr(ident.impl()));
-                operationFunction = operationCallCustomGetter;
+            if (structure->isDictionary()) {
+                if (structure->hasBeenFlattenedBefore())
+                    return GiveUpOnCache;
+                structure->flattenDictionaryStructure(vm, jsCast<JSObject*>(baseCell));
             }
             
-            // Need to make sure that whenever this call is made in the future, we remember the
-            // place that we made it from. It just so happens to be the place that we are at
-            // right now!
-            stubJit.store32(
-                MacroAssembler::TrustedImm32(exec->locationAsRawBits()),
-                CCallHelpers::tagFor(static_cast<VirtualRegister>(JSStack::ArgumentCount)));
-            
-            operationCall = stubJit.call();
-#if USE(JSVALUE64)
-            stubJit.move(GPRInfo::returnValueGPR, resultGPR);
-#else
-            stubJit.setupResults(resultGPR, resultTagGPR);
-#endif
-            success = stubJit.emitExceptionCheck(CCallHelpers::InvertedExceptionCheck);
-            
-            stubJit.setupArgumentsExecState();
-            handlerCall = stubJit.call();
-            stubJit.jumpToExceptionHandler();
-        } else {
-            if (isInlineOffset(slot.cachedOffset())) {
-#if USE(JSVALUE64)
-                stubJit.load64(MacroAssembler::Address(baseGPR, offsetRelativeToBase(slot.cachedOffset())), resultGPR);
-#else
-                if (baseGPR == resultTagGPR) {
-                    stubJit.load32(MacroAssembler::Address(baseGPR, offsetRelativeToBase(slot.cachedOffset()) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.payload)), resultGPR);
-                    stubJit.load32(MacroAssembler::Address(baseGPR, offsetRelativeToBase(slot.cachedOffset()) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.tag)), resultTagGPR);
-                } else {
-                    stubJit.load32(MacroAssembler::Address(baseGPR, offsetRelativeToBase(slot.cachedOffset()) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.tag)), resultTagGPR);
-                    stubJit.load32(MacroAssembler::Address(baseGPR, offsetRelativeToBase(slot.cachedOffset()) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.payload)), resultGPR);
-                }
-#endif
+            if (slot.isUnset() && structure->typeInfo().getOwnPropertySlotIsImpureForPropertyAbsence())
+                return GiveUpOnCache;
+
+            if (slot.isUnset()) {
+                conditionSet = generateConditionsForPropertyMiss(
+                    vm, codeBlock, exec, structure, propertyName.impl());
             } else {
-                stubJit.loadPtr(MacroAssembler::Address(baseGPR, JSObject::butterflyOffset()), resultGPR);
-#if USE(JSVALUE64)
-                stubJit.load64(MacroAssembler::Address(resultGPR, offsetRelativeToBase(slot.cachedOffset())), resultGPR);
-#else
-                stubJit.load32(MacroAssembler::Address(resultGPR, offsetRelativeToBase(slot.cachedOffset()) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.tag)), resultTagGPR);
-                stubJit.load32(MacroAssembler::Address(resultGPR, offsetRelativeToBase(slot.cachedOffset()) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.payload)), resultGPR);
-#endif
+                conditionSet = generateConditionsForPrototypePropertyHit(
+                    vm, codeBlock, exec, structure, slot.slotBase(),
+                    propertyName.impl());
             }
-            success = stubJit.jump();
-            isDirect = true;
+            
+            if (!conditionSet.isValid())
+                return GiveUpOnCache;
+
+            offset = slot.isUnset() ? invalidOffset : conditionSet.slotBaseCondition().offset();
         }
 
-        LinkBuffer patchBuffer(*vm, &stubJit, codeBlock);
-        
-        patchBuffer.link(wrongStruct, slowCase);
-        patchBuffer.link(success, stubInfo.callReturnLocation.labelAtOffset(stubInfo.patch.deltaCallToDone));
-        if (!isDirect) {
-            patchBuffer.link(operationCall, operationFunction);
-            patchBuffer.link(handlerCall, lookupExceptionHandler);
+        JSFunction* getter = nullptr;
+        if (slot.isCacheableGetter())
+            getter = jsDynamicCast<JSFunction*>(vm, slot.getterSetter()->getter());
+
+        DOMJIT::GetterSetter* domJIT = nullptr;
+        if (slot.isCacheableCustom() && slot.domJIT())
+            domJIT = slot.domJIT();
+
+        if (kind == GetByIDKind::Try) {
+            AccessCase::AccessType type;
+            if (slot.isCacheableValue())
+                type = AccessCase::Load;
+            else if (slot.isUnset())
+                type = AccessCase::Miss;
+            else if (slot.isCacheableGetter())
+                type = AccessCase::GetGetter;
+            else
+                RELEASE_ASSERT_NOT_REACHED();
+
+            newCase = ProxyableAccessCase::create(vm, codeBlock, type, offset, structure, conditionSet, loadTargetFromProxy, slot.watchpointSet());
+        } else if (!loadTargetFromProxy && getter && IntrinsicGetterAccessCase::canEmitIntrinsicGetter(getter, structure))
+            newCase = IntrinsicGetterAccessCase::create(vm, codeBlock, slot.cachedOffset(), structure, conditionSet, getter);
+        else {
+            if (slot.isCacheableValue() || slot.isUnset()) {
+                newCase = ProxyableAccessCase::create(vm, codeBlock, slot.isUnset() ? AccessCase::Miss : AccessCase::Load,
+                    offset, structure, conditionSet, loadTargetFromProxy, slot.watchpointSet());
+            } else {
+                AccessCase::AccessType type;
+                if (slot.isCacheableGetter())
+                    type = AccessCase::Getter;
+                else if (slot.attributes() & CustomAccessor)
+                    type = AccessCase::CustomAccessorGetter;
+                else
+                    type = AccessCase::CustomValueGetter;
+
+                newCase = GetterSetterAccessCase::create(
+                    vm, codeBlock, type, offset, structure, conditionSet, loadTargetFromProxy,
+                    slot.watchpointSet(), slot.isCacheableCustom() ? slot.customGetter() : nullptr,
+                    slot.isCacheableCustom() ? slot.slotBase() : nullptr,
+                    domJIT);
+            }
         }
-        
-        RefPtr<JITStubRoutine> stubRoutine =
-            createJITStubRoutine(
-                FINALIZE_DFG_CODE(
-                    patchBuffer,
-                    ("DFG GetById polymorphic list access for %s, return point %p",
-                        toCString(*exec->codeBlock()).data(), stubInfo.callReturnLocation.labelAtOffset(
-                            stubInfo.patch.deltaCallToDone).executableAddress())),
-                *vm,
-                codeBlock->ownerExecutable(),
-                slot.isCacheableGetter() || slot.isCacheableCustom());
-        
-        polymorphicStructureList->list[listIndex].set(*vm, codeBlock->ownerExecutable(), stubRoutine, structure, isDirect);
-        
-        patchJumpToGetByIdStub(codeBlock, stubInfo, stubRoutine.get());
-        return listIndex < (POLYMORPHIC_LIST_CACHE_SIZE - 1);
     }
-    
-    if (baseValue.asCell()->structure()->typeInfo().prohibitsPropertyCaching()
-        || baseValue.asCell()->structure()->isDictionary())
-        return false;
-    
-    if (!stubInfo.patch.registersFlushed) {
-        // We cannot do as much inline caching if the registers were not flushed prior to this GetById. In particular,
-        // non-Value cached properties require planting calls, which requires registers to have been flushed. Thus,
-        // if registers were not flushed, don't do non-Value caching.
-        if (!slot.isCacheableValue())
-            return false;
-    }
-    
 
-    PropertyOffset offset = slot.cachedOffset();
-    size_t count = normalizePrototypeChainForChainAccess(exec, baseValue, slot.slotBase(), ident, offset);
-    if (count == InvalidPrototypeChain)
-        return false;
+    LOG_IC((ICEvent::GetByIdAddAccessCase, baseValue.classInfoOrNull(vm), propertyName));
 
-    StructureChain* prototypeChain = structure->prototypeChain(exec);
-    
-    PolymorphicAccessStructureList* polymorphicStructureList;
-    int listIndex;
-    CodeLocationLabel slowCase;
-    if (!getPolymorphicStructureList(vm, codeBlock, stubInfo, polymorphicStructureList, listIndex, slowCase))
-        return false;
-    
-    stubInfo.u.getByIdProtoList.listSize++;
-    
-    RefPtr<JITStubRoutine> stubRoutine;
-    
-    if (generateProtoChainAccessStub(exec, slot, ident, stubInfo, prototypeChain, count, offset, structure,
-        stubInfo.callReturnLocation.labelAtOffset(stubInfo.patch.deltaCallToDone),
-        slowCase, stubRoutine) == ProtoChainGenerationFailed)
-        return false;
-    
-    polymorphicStructureList->list[listIndex].set(*vm, codeBlock->ownerExecutable(), stubRoutine, structure, slot.isCacheableValue());
-    
-    patchJumpToGetByIdStub(codeBlock, stubInfo, stubRoutine.get());
+    AccessGenerationResult result = stubInfo.addAccessCase(codeBlock, propertyName, WTFMove(newCase));
+
+    if (result.generatedSomeCode()) {
+        LOG_IC((ICEvent::GetByIdReplaceWithJump, baseValue.classInfoOrNull(vm), propertyName));
+        
+        RELEASE_ASSERT(result.code());
+        InlineAccess::rewireStubAsJump(exec->vm(), stubInfo, CodeLocationLabel(result.code()));
+    }
     
-    return listIndex < (POLYMORPHIC_LIST_CACHE_SIZE - 1);
+    return result.shouldGiveUpNow() ? GiveUpOnCache : RetryCacheLater;
 }
 
-void buildGetByIDList(ExecState* exec, JSValue baseValue, const Identifier& propertyName, const PropertySlot& slot, StructureStubInfo& stubInfo)
+void repatchGetByID(ExecState* exec, JSValue baseValue, const Identifier& propertyName, const PropertySlot& slot, StructureStubInfo& stubInfo, GetByIDKind kind)
 {
-    GCSafeConcurrentJITLocker locker(exec->codeBlock()->m_lock, exec->vm().heap);
+    SuperSamplerScope superSamplerScope(false);
+    GCSafeConcurrentJSLocker locker(exec->codeBlock()->m_lock, exec->vm().heap);
     
-    bool dontChangeCall = tryBuildGetByIDList(exec, baseValue, propertyName, slot, stubInfo);
-    if (!dontChangeCall)
-        repatchCall(exec->codeBlock(), stubInfo.callReturnLocation, operationGetById);
+    if (tryCacheGetByID(exec, baseValue, propertyName, slot, stubInfo, kind) == GiveUpOnCache)
+        ftlThunkAwareRepatchCall(exec->codeBlock(), stubInfo.slowPathCallLocation(), appropriateGenericGetByIdFunction(kind));
 }
 
 static V_JITOperation_ESsiJJI appropriateGenericPutByIdFunction(const PutPropertySlot &slot, PutKind putKind)
@@ -750,862 +347,666 @@ static V_JITOperation_ESsiJJI appropriateGenericPutByIdFunction(const PutPropert
     return operationPutByIdNonStrict;
 }
 
-static V_JITOperation_ESsiJJI appropriateListBuildingPutByIdFunction(const PutPropertySlot &slot, PutKind putKind)
+static V_JITOperation_ESsiJJI appropriateOptimizingPutByIdFunction(const PutPropertySlot &slot, PutKind putKind)
 {
     if (slot.isStrictMode()) {
         if (putKind == Direct)
-            return operationPutByIdDirectStrictBuildList;
-        return operationPutByIdStrictBuildList;
+            return operationPutByIdDirectStrictOptimize;
+        return operationPutByIdStrictOptimize;
     }
     if (putKind == Direct)
-        return operationPutByIdDirectNonStrictBuildList;
-    return operationPutByIdNonStrictBuildList;
+        return operationPutByIdDirectNonStrictOptimize;
+    return operationPutByIdNonStrictOptimize;
 }
 
-#if ENABLE(GGC)
-static MacroAssembler::Call storeToWriteBarrierBuffer(CCallHelpers& jit, GPRReg cell, GPRReg scratch1, GPRReg scratch2, GPRReg callFrameRegister, ScratchRegisterAllocator& allocator)
+static InlineCacheAction tryCachePutByID(ExecState* exec, JSValue baseValue, Structure* structure, const Identifier& ident, const PutPropertySlot& slot, StructureStubInfo& stubInfo, PutKind putKind)
 {
-    ASSERT(scratch1 != scratch2);
-    WriteBarrierBuffer* writeBarrierBuffer = &jit.vm()->heap.writeBarrierBuffer();
-    jit.move(MacroAssembler::TrustedImmPtr(writeBarrierBuffer), scratch1);
-    jit.load32(MacroAssembler::Address(scratch1, WriteBarrierBuffer::currentIndexOffset()), scratch2);
-    MacroAssembler::Jump needToFlush = jit.branch32(MacroAssembler::AboveOrEqual, scratch2, MacroAssembler::Address(scratch1, WriteBarrierBuffer::capacityOffset()));
-
-    jit.add32(MacroAssembler::TrustedImm32(1), scratch2);
-    jit.store32(scratch2, MacroAssembler::Address(scratch1, WriteBarrierBuffer::currentIndexOffset()));
-
-    jit.loadPtr(MacroAssembler::Address(scratch1, WriteBarrierBuffer::bufferOffset()), scratch1);
-    // We use an offset of -sizeof(void*) because we already added 1 to scratch2.
-    jit.storePtr(cell, MacroAssembler::BaseIndex(scratch1, scratch2, MacroAssembler::ScalePtr, static_cast<int32_t>(-sizeof(void*))));
-
-    MacroAssembler::Jump done = jit.jump();
-    needToFlush.link(&jit);
-
-    ScratchBuffer* scratchBuffer = jit.vm()->scratchBufferForSize(allocator.desiredScratchBufferSize());
-    allocator.preserveUsedRegistersToScratchBuffer(jit, scratchBuffer, scratch1);
-
-    unsigned bytesFromBase = allocator.numberOfReusedRegisters() * sizeof(void*);
-    unsigned bytesToSubtract = 0;
-#if CPU(X86)
-    bytesToSubtract += 2 * sizeof(void*);
-    bytesFromBase += bytesToSubtract;
-#endif
-    unsigned currentAlignment = bytesFromBase % stackAlignmentBytes();
-    bytesToSubtract += currentAlignment;
-
-    if (bytesToSubtract)
-        jit.subPtr(MacroAssembler::TrustedImm32(bytesToSubtract), MacroAssembler::stackPointerRegister); 
-
-    jit.setupArguments(callFrameRegister, cell);
-    MacroAssembler::Call call = jit.call();
+    if (forceICFailure(exec))
+        return GiveUpOnCache;
+    
+    CodeBlock* codeBlock = exec->codeBlock();
+    VM& vm = exec->vm();
 
-    if (bytesToSubtract)
-        jit.addPtr(MacroAssembler::TrustedImm32(bytesToSubtract), MacroAssembler::stackPointerRegister);
-    allocator.restoreUsedRegistersFromScratchBuffer(jit, scratchBuffer, scratch1);
+    if (!baseValue.isCell())
+        return GiveUpOnCache;
+    
+    if (!slot.isCacheablePut() && !slot.isCacheableCustom() && !slot.isCacheableSetter())
+        return GiveUpOnCache;
 
-    done.link(&jit);
+    if (!structure->propertyAccessesAreCacheable())
+        return GiveUpOnCache;
+
+    std::unique_ptr<AccessCase> newCase;
+
+    if (slot.base() == baseValue && slot.isCacheablePut()) {
+        if (slot.type() == PutPropertySlot::ExistingProperty) {
+            structure->didCachePropertyReplacement(vm, slot.cachedOffset());
+        
+            if (stubInfo.cacheType == CacheType::Unset
+                && InlineAccess::canGenerateSelfPropertyReplace(stubInfo, slot.cachedOffset())
+                && !structure->needImpurePropertyWatchpoint()
+                && !structure->inferredTypeFor(ident.impl())) {
+                
+                bool generatedCodeInline = InlineAccess::generateSelfPropertyReplace(vm, stubInfo, structure, slot.cachedOffset());
+                if (generatedCodeInline) {
+                    LOG_IC((ICEvent::PutByIdSelfPatch, structure->classInfo(), ident));
+                    ftlThunkAwareRepatchCall(codeBlock, stubInfo.slowPathCallLocation(), appropriateOptimizingPutByIdFunction(slot, putKind));
+                    stubInfo.initPutByIdReplace(codeBlock, structure, slot.cachedOffset());
+                    return RetryCacheLater;
+                }
+            }
 
-    return call;
-}
+            newCase = AccessCase::create(vm, codeBlock, AccessCase::Replace, slot.cachedOffset(), structure);
+        } else {
+            ASSERT(slot.type() == PutPropertySlot::NewProperty);
 
-static MacroAssembler::Call writeBarrier(CCallHelpers& jit, GPRReg owner, GPRReg scratch1, GPRReg scratch2, GPRReg callFrameRegister, ScratchRegisterAllocator& allocator)
-{
-    ASSERT(owner != scratch1);
-    ASSERT(owner != scratch2);
+            if (!structure->isObject())
+                return GiveUpOnCache;
 
-    MacroAssembler::Jump definitelyNotMarked = DFG::SpeculativeJIT::genericWriteBarrier(jit, owner, scratch1, scratch2);
-    MacroAssembler::Call call = storeToWriteBarrierBuffer(jit, owner, scratch1, scratch2, callFrameRegister, allocator);
-    definitelyNotMarked.link(&jit);
-    return call;
-}
-#endif // ENABLE(GGC)
-
-static void emitPutReplaceStub(
-    ExecState* exec,
-    JSValue,
-    const Identifier&,
-    const PutPropertySlot& slot,
-    StructureStubInfo& stubInfo,
-    PutKind,
-    Structure* structure,
-    CodeLocationLabel failureLabel,
-    RefPtr<JITStubRoutine>& stubRoutine)
-{
-    VM* vm = &exec->vm();
-#if ENABLE(GGC)
-    GPRReg callFrameRegister = static_cast<GPRReg>(stubInfo.patch.callFrameRegister);
-#endif
-    GPRReg baseGPR = static_cast<GPRReg>(stubInfo.patch.baseGPR);
-#if USE(JSVALUE32_64)
-    GPRReg valueTagGPR = static_cast<GPRReg>(stubInfo.patch.valueTagGPR);
-#endif
-    GPRReg valueGPR = static_cast<GPRReg>(stubInfo.patch.valueGPR);
-
-    ScratchRegisterAllocator allocator(stubInfo.patch.usedRegisters);
-    allocator.lock(baseGPR);
-#if USE(JSVALUE32_64)
-    allocator.lock(valueTagGPR);
-#endif
-    allocator.lock(valueGPR);
-    
-    GPRReg scratchGPR1 = allocator.allocateScratchGPR();
-#if ENABLE(GGC)
-    GPRReg scratchGPR2 = allocator.allocateScratchGPR();
-#endif
+            if (structure->isDictionary()) {
+                if (structure->hasBeenFlattenedBefore())
+                    return GiveUpOnCache;
+                structure->flattenDictionaryStructure(vm, jsCast<JSObject*>(baseValue));
+            }
 
-    CCallHelpers stubJit(vm, exec->codeBlock());
+            PropertyOffset offset;
+            Structure* newStructure =
+                Structure::addPropertyTransitionToExistingStructureConcurrently(
+                    structure, ident.impl(), 0, offset);
+            if (!newStructure || !newStructure->propertyAccessesAreCacheable())
+                return GiveUpOnCache;
 
-    allocator.preserveReusedRegistersByPushing(stubJit);
+            ASSERT(newStructure->previousID() == structure);
+            ASSERT(!newStructure->isDictionary());
+            ASSERT(newStructure->isObject());
+            
+            ObjectPropertyConditionSet conditionSet;
+            if (putKind == NotDirect) {
+                conditionSet =
+                    generateConditionsForPropertySetterMiss(
+                        vm, codeBlock, exec, newStructure, ident.impl());
+                if (!conditionSet.isValid())
+                    return GiveUpOnCache;
+            }
 
-    MacroAssembler::Jump badStructure = stubJit.branchPtr(
-        MacroAssembler::NotEqual,
-        MacroAssembler::Address(baseGPR, JSCell::structureOffset()),
-        MacroAssembler::TrustedImmPtr(structure));
+            newCase = AccessCase::create(vm, codeBlock, offset, structure, newStructure, conditionSet);
+        }
+    } else if (slot.isCacheableCustom() || slot.isCacheableSetter()) {
+        if (slot.isCacheableCustom()) {
+            ObjectPropertyConditionSet conditionSet;
+
+            if (slot.base() != baseValue) {
+                conditionSet =
+                    generateConditionsForPrototypePropertyHitCustom(
+                        vm, codeBlock, exec, structure, slot.base(), ident.impl());
+                if (!conditionSet.isValid())
+                    return GiveUpOnCache;
+            }
 
-#if USE(JSVALUE64)
-    if (isInlineOffset(slot.cachedOffset()))
-        stubJit.store64(valueGPR, MacroAssembler::Address(baseGPR, JSObject::offsetOfInlineStorage() + offsetInInlineStorage(slot.cachedOffset()) * sizeof(JSValue)));
-    else {
-        stubJit.loadPtr(MacroAssembler::Address(baseGPR, JSObject::butterflyOffset()), scratchGPR1);
-        stubJit.store64(valueGPR, MacroAssembler::Address(scratchGPR1, offsetInButterfly(slot.cachedOffset()) * sizeof(JSValue)));
-    }
-#elif USE(JSVALUE32_64)
-    if (isInlineOffset(slot.cachedOffset())) {
-        stubJit.store32(valueGPR, MacroAssembler::Address(baseGPR, JSObject::offsetOfInlineStorage() + offsetInInlineStorage(slot.cachedOffset()) * sizeof(JSValue) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.payload)));
-        stubJit.store32(valueTagGPR, MacroAssembler::Address(baseGPR, JSObject::offsetOfInlineStorage() + offsetInInlineStorage(slot.cachedOffset()) * sizeof(JSValue) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.tag)));
-    } else {
-        stubJit.loadPtr(MacroAssembler::Address(baseGPR, JSObject::butterflyOffset()), scratchGPR1);
-        stubJit.store32(valueGPR, MacroAssembler::Address(scratchGPR1, offsetInButterfly(slot.cachedOffset()) * sizeof(JSValue) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.payload)));
-        stubJit.store32(valueTagGPR, MacroAssembler::Address(scratchGPR1, offsetInButterfly(slot.cachedOffset()) * sizeof(JSValue) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.tag)));
+            newCase = GetterSetterAccessCase::create(
+                vm, codeBlock, slot.isCustomAccessor() ? AccessCase::CustomAccessorSetter : AccessCase::CustomValueSetter, structure, invalidOffset, conditionSet,
+                slot.customSetter(), slot.base());
+        } else {
+            ObjectPropertyConditionSet conditionSet;
+            PropertyOffset offset;
+
+            if (slot.base() != baseValue) {
+                conditionSet =
+                    generateConditionsForPrototypePropertyHit(
+                        vm, codeBlock, exec, structure, slot.base(), ident.impl());
+                if (!conditionSet.isValid())
+                    return GiveUpOnCache;
+                offset = conditionSet.slotBaseCondition().offset();
+            } else
+                offset = slot.cachedOffset();
+
+            newCase = GetterSetterAccessCase::create(
+                vm, codeBlock, AccessCase::Setter, structure, offset, conditionSet);
+        }
     }
-#endif
-    
-#if ENABLE(GGC)
-    MacroAssembler::Call writeBarrierOperation = writeBarrier(stubJit, baseGPR, scratchGPR1, scratchGPR2, callFrameRegister, allocator);
-#endif
+
+    LOG_IC((ICEvent::PutByIdAddAccessCase, structure->classInfo(), ident));
     
-    MacroAssembler::Jump success;
-    MacroAssembler::Jump failure;
+    AccessGenerationResult result = stubInfo.addAccessCase(codeBlock, ident, WTFMove(newCase));
     
-    if (allocator.didReuseRegisters()) {
-        allocator.restoreReusedRegistersByPopping(stubJit);
-        success = stubJit.jump();
+    if (result.generatedSomeCode()) {
+        LOG_IC((ICEvent::PutByIdReplaceWithJump, structure->classInfo(), ident));
         
-        badStructure.link(&stubJit);
-        allocator.restoreReusedRegistersByPopping(stubJit);
-        failure = stubJit.jump();
-    } else {
-        success = stubJit.jump();
-        failure = badStructure;
+        RELEASE_ASSERT(result.code());
+
+        InlineAccess::rewireStubAsJump(vm, stubInfo, CodeLocationLabel(result.code()));
     }
     
-    LinkBuffer patchBuffer(*vm, &stubJit, exec->codeBlock());
-#if ENABLE(GGC)
-    patchBuffer.link(writeBarrierOperation, operationFlushWriteBarrierBuffer);
-#endif
-    patchBuffer.link(success, stubInfo.callReturnLocation.labelAtOffset(stubInfo.patch.deltaCallToDone));
-    patchBuffer.link(failure, failureLabel);
-            
-    stubRoutine = FINALIZE_CODE_FOR_DFG_STUB(
-        patchBuffer,
-        ("DFG PutById replace stub for %s, return point %p",
-            toCString(*exec->codeBlock()).data(), stubInfo.callReturnLocation.labelAtOffset(
-                stubInfo.patch.deltaCallToDone).executableAddress()));
+    return result.shouldGiveUpNow() ? GiveUpOnCache : RetryCacheLater;
 }
 
-static void emitPutTransitionStub(
-    ExecState* exec,
-    JSValue,
-    const Identifier&,
-    const PutPropertySlot& slot,
-    StructureStubInfo& stubInfo,
-    PutKind putKind,
-    Structure* structure,
-    Structure* oldStructure,
-    StructureChain* prototypeChain,
-    CodeLocationLabel failureLabel,
-    RefPtr<JITStubRoutine>& stubRoutine)
+void repatchPutByID(ExecState* exec, JSValue baseValue, Structure* structure, const Identifier& propertyName, const PutPropertySlot& slot, StructureStubInfo& stubInfo, PutKind putKind)
 {
-    VM* vm = &exec->vm();
-
-    GPRReg callFrameRegister = static_cast<GPRReg>(stubInfo.patch.callFrameRegister);
-    GPRReg baseGPR = static_cast<GPRReg>(stubInfo.patch.baseGPR);
-#if USE(JSVALUE32_64)
-    GPRReg valueTagGPR = static_cast<GPRReg>(stubInfo.patch.valueTagGPR);
-#endif
-    GPRReg valueGPR = static_cast<GPRReg>(stubInfo.patch.valueGPR);
-    
-    ScratchRegisterAllocator allocator(stubInfo.patch.usedRegisters);
-    allocator.lock(baseGPR);
-#if USE(JSVALUE32_64)
-    allocator.lock(valueTagGPR);
-#endif
-    allocator.lock(valueGPR);
-    
-    CCallHelpers stubJit(vm);
-    
-    bool needThirdScratch = false;
-    if (structure->outOfLineCapacity() != oldStructure->outOfLineCapacity()
-        && oldStructure->outOfLineCapacity()) {
-        needThirdScratch = true;
-    }
-
-    GPRReg scratchGPR1 = allocator.allocateScratchGPR();
-    ASSERT(scratchGPR1 != baseGPR);
-    ASSERT(scratchGPR1 != valueGPR);
+    SuperSamplerScope superSamplerScope(false);
+    GCSafeConcurrentJSLocker locker(exec->codeBlock()->m_lock, exec->vm().heap);
     
-    GPRReg scratchGPR2 = allocator.allocateScratchGPR();
-    ASSERT(scratchGPR2 != baseGPR);
-    ASSERT(scratchGPR2 != valueGPR);
-    ASSERT(scratchGPR2 != scratchGPR1);
-
-    GPRReg scratchGPR3;
-    if (needThirdScratch) {
-        scratchGPR3 = allocator.allocateScratchGPR();
-        ASSERT(scratchGPR3 != baseGPR);
-        ASSERT(scratchGPR3 != valueGPR);
-        ASSERT(scratchGPR3 != scratchGPR1);
-        ASSERT(scratchGPR3 != scratchGPR2);
-    } else
-        scratchGPR3 = InvalidGPRReg;
-    
-    allocator.preserveReusedRegistersByPushing(stubJit);
+    if (tryCachePutByID(exec, baseValue, structure, propertyName, slot, stubInfo, putKind) == GiveUpOnCache)
+        ftlThunkAwareRepatchCall(exec->codeBlock(), stubInfo.slowPathCallLocation(), appropriateGenericPutByIdFunction(slot, putKind));
+}
 
-    MacroAssembler::JumpList failureCases;
-            
-    ASSERT(oldStructure->transitionWatchpointSetHasBeenInvalidated());
+static InlineCacheAction tryRepatchIn(
+    ExecState* exec, JSCell* base, const Identifier& ident, bool wasFound,
+    const PropertySlot& slot, StructureStubInfo& stubInfo)
+{
+    if (forceICFailure(exec))
+        return GiveUpOnCache;
     
-    failureCases.append(stubJit.branchPtr(MacroAssembler::NotEqual, MacroAssembler::Address(baseGPR, JSCell::structureOffset()), MacroAssembler::TrustedImmPtr(oldStructure)));
+    if (!base->structure()->propertyAccessesAreCacheable() || (!wasFound && !base->structure()->propertyAccessesAreCacheableForAbsence()))
+        return GiveUpOnCache;
     
-    addStructureTransitionCheck(
-        oldStructure->storedPrototype(), exec->codeBlock(), stubInfo, stubJit, failureCases,
-        scratchGPR1);
-            
-    if (putKind == NotDirect) {
-        for (WriteBarrier<Structure>* it = prototypeChain->head(); *it; ++it) {
-            addStructureTransitionCheck(
-                (*it)->storedPrototype(), exec->codeBlock(), stubInfo, stubJit, failureCases,
-                scratchGPR1);
-        }
+    if (wasFound) {
+        if (!slot.isCacheable())
+            return GiveUpOnCache;
     }
-
-    MacroAssembler::JumpList slowPath;
     
-    bool scratchGPR1HasStorage = false;
+    CodeBlock* codeBlock = exec->codeBlock();
+    VM& vm = exec->vm();
+    Structure* structure = base->structure(vm);
     
-    if (structure->outOfLineCapacity() != oldStructure->outOfLineCapacity()) {
-        size_t newSize = structure->outOfLineCapacity() * sizeof(JSValue);
-        CopiedAllocator* copiedAllocator = &vm->heap.storageAllocator();
-        
-        if (!oldStructure->outOfLineCapacity()) {
-            stubJit.loadPtr(&copiedAllocator->m_currentRemaining, scratchGPR1);
-            slowPath.append(stubJit.branchSubPtr(MacroAssembler::Signed, MacroAssembler::TrustedImm32(newSize), scratchGPR1));
-            stubJit.storePtr(scratchGPR1, &copiedAllocator->m_currentRemaining);
-            stubJit.negPtr(scratchGPR1);
-            stubJit.addPtr(MacroAssembler::AbsoluteAddress(&copiedAllocator->m_currentPayloadEnd), scratchGPR1);
-            stubJit.addPtr(MacroAssembler::TrustedImm32(sizeof(JSValue)), scratchGPR1);
-        } else {
-            size_t oldSize = oldStructure->outOfLineCapacity() * sizeof(JSValue);
-            ASSERT(newSize > oldSize);
-            
-            stubJit.loadPtr(MacroAssembler::Address(baseGPR, JSObject::butterflyOffset()), scratchGPR3);
-            stubJit.loadPtr(&copiedAllocator->m_currentRemaining, scratchGPR1);
-            slowPath.append(stubJit.branchSubPtr(MacroAssembler::Signed, MacroAssembler::TrustedImm32(newSize), scratchGPR1));
-            stubJit.storePtr(scratchGPR1, &copiedAllocator->m_currentRemaining);
-            stubJit.negPtr(scratchGPR1);
-            stubJit.addPtr(MacroAssembler::AbsoluteAddress(&copiedAllocator->m_currentPayloadEnd), scratchGPR1);
-            stubJit.addPtr(MacroAssembler::TrustedImm32(sizeof(JSValue)), scratchGPR1);
-            // We have scratchGPR1 = new storage, scratchGPR3 = old storage, scratchGPR2 = available
-            for (size_t offset = 0; offset < oldSize; offset += sizeof(void*)) {
-                stubJit.loadPtr(MacroAssembler::Address(scratchGPR3, -static_cast<ptrdiff_t>(offset + sizeof(JSValue) + sizeof(void*))), scratchGPR2);
-                stubJit.storePtr(scratchGPR2, MacroAssembler::Address(scratchGPR1, -static_cast<ptrdiff_t>(offset + sizeof(JSValue) + sizeof(void*))));
-            }
+    ObjectPropertyConditionSet conditionSet;
+    if (wasFound) {
+        if (slot.slotBase() != base) {
+            conditionSet = generateConditionsForPrototypePropertyHit(
+                vm, codeBlock, exec, structure, slot.slotBase(), ident.impl());
         }
-        
-        stubJit.storePtr(scratchGPR1, MacroAssembler::Address(baseGPR, JSObject::butterflyOffset()));
-        scratchGPR1HasStorage = true;
-    }
-
-    stubJit.storePtr(MacroAssembler::TrustedImmPtr(structure), MacroAssembler::Address(baseGPR, JSCell::structureOffset()));
-#if USE(JSVALUE64)
-    if (isInlineOffset(slot.cachedOffset()))
-        stubJit.store64(valueGPR, MacroAssembler::Address(baseGPR, JSObject::offsetOfInlineStorage() + offsetInInlineStorage(slot.cachedOffset()) * sizeof(JSValue)));
-    else {
-        if (!scratchGPR1HasStorage)
-            stubJit.loadPtr(MacroAssembler::Address(baseGPR, JSObject::butterflyOffset()), scratchGPR1);
-        stubJit.store64(valueGPR, MacroAssembler::Address(scratchGPR1, offsetInButterfly(slot.cachedOffset()) * sizeof(JSValue)));
-    }
-#elif USE(JSVALUE32_64)
-    if (isInlineOffset(slot.cachedOffset())) {
-        stubJit.store32(valueGPR, MacroAssembler::Address(baseGPR, JSObject::offsetOfInlineStorage() + offsetInInlineStorage(slot.cachedOffset()) * sizeof(JSValue) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.payload)));
-        stubJit.store32(valueTagGPR, MacroAssembler::Address(baseGPR, JSObject::offsetOfInlineStorage() + offsetInInlineStorage(slot.cachedOffset()) * sizeof(JSValue) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.tag)));
     } else {
-        if (!scratchGPR1HasStorage)
-            stubJit.loadPtr(MacroAssembler::Address(baseGPR, JSObject::butterflyOffset()), scratchGPR1);
-        stubJit.store32(valueGPR, MacroAssembler::Address(scratchGPR1, offsetInButterfly(slot.cachedOffset()) * sizeof(JSValue) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.payload)));
-        stubJit.store32(valueTagGPR, MacroAssembler::Address(scratchGPR1, offsetInButterfly(slot.cachedOffset()) * sizeof(JSValue) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.tag)));
+        conditionSet = generateConditionsForPropertyMiss(
+            vm, codeBlock, exec, structure, ident.impl());
     }
-#endif
-    
-#if ENABLE(GGC)
-    MacroAssembler::Call writeBarrierOperation = writeBarrier(stubJit, baseGPR, scratchGPR1, scratchGPR2, callFrameRegister, allocator);
-#endif
-    
-    MacroAssembler::Jump success;
-    MacroAssembler::Jump failure;
-            
-    if (allocator.didReuseRegisters()) {
-        allocator.restoreReusedRegistersByPopping(stubJit);
-        success = stubJit.jump();
+    if (!conditionSet.isValid())
+        return GiveUpOnCache;
 
-        failureCases.link(&stubJit);
-        allocator.restoreReusedRegistersByPopping(stubJit);
-        failure = stubJit.jump();
-    } else
-        success = stubJit.jump();
-    
-    MacroAssembler::Call operationCall;
-    MacroAssembler::Jump successInSlowPath;
+    LOG_IC((ICEvent::InAddAccessCase, structure->classInfo(), ident));
+
+    std::unique_ptr<AccessCase> newCase = AccessCase::create(
+        vm, codeBlock, wasFound ? AccessCase::InHit : AccessCase::InMiss, invalidOffset, structure, conditionSet);
+
+    AccessGenerationResult result = stubInfo.addAccessCase(codeBlock, ident, WTFMove(newCase));
     
-    if (structure->outOfLineCapacity() != oldStructure->outOfLineCapacity()) {
-        slowPath.link(&stubJit);
+    if (result.generatedSomeCode()) {
+        LOG_IC((ICEvent::InReplaceWithJump, structure->classInfo(), ident));
         
-        allocator.restoreReusedRegistersByPopping(stubJit);
-        ScratchBuffer* scratchBuffer = vm->scratchBufferForSize(allocator.desiredScratchBufferSize());
-        allocator.preserveUsedRegistersToScratchBuffer(stubJit, scratchBuffer, scratchGPR1);
-#if USE(JSVALUE64)
-        stubJit.setupArguments(callFrameRegister, baseGPR, MacroAssembler::TrustedImmPtr(structure), MacroAssembler::TrustedImm32(slot.cachedOffset()), valueGPR);
-#else
-        stubJit.setupArguments(callFrameRegister, baseGPR, MacroAssembler::TrustedImmPtr(structure), MacroAssembler::TrustedImm32(slot.cachedOffset()), valueGPR, valueTagGPR);
-#endif
-        operationCall = stubJit.call();
-        allocator.restoreUsedRegistersFromScratchBuffer(stubJit, scratchBuffer, scratchGPR1);
-        successInSlowPath = stubJit.jump();
-    }
-    
-    LinkBuffer patchBuffer(*vm, &stubJit, exec->codeBlock());
-#if ENABLE(GGC)
-    patchBuffer.link(writeBarrierOperation, operationFlushWriteBarrierBuffer);
-#endif
-    patchBuffer.link(success, stubInfo.callReturnLocation.labelAtOffset(stubInfo.patch.deltaCallToDone));
-    if (allocator.didReuseRegisters())
-        patchBuffer.link(failure, failureLabel);
-    else
-        patchBuffer.link(failureCases, failureLabel);
-    if (structure->outOfLineCapacity() != oldStructure->outOfLineCapacity()) {
-        patchBuffer.link(operationCall, operationReallocateStorageAndFinishPut);
-        patchBuffer.link(successInSlowPath, stubInfo.callReturnLocation.labelAtOffset(stubInfo.patch.deltaCallToDone));
+        RELEASE_ASSERT(result.code());
+
+        MacroAssembler::repatchJump(
+            stubInfo.patchableJumpForIn(),
+            CodeLocationLabel(result.code()));
     }
     
-    stubRoutine =
-        createJITStubRoutine(
-            FINALIZE_DFG_CODE(
-                patchBuffer,
-                ("DFG PutById %stransition stub (%p -> %p) for %s, return point %p",
-                    structure->outOfLineCapacity() != oldStructure->outOfLineCapacity() ? "reallocating " : "",
-                    oldStructure, structure,
-                    toCString(*exec->codeBlock()).data(), stubInfo.callReturnLocation.labelAtOffset(
-                        stubInfo.patch.deltaCallToDone).executableAddress())),
-            *vm,
-            exec->codeBlock()->ownerExecutable(),
-            structure->outOfLineCapacity() != oldStructure->outOfLineCapacity(),
-            structure);
+    return result.shouldGiveUpNow() ? GiveUpOnCache : RetryCacheLater;
 }
 
-static bool tryCachePutByID(ExecState* exec, JSValue baseValue, const Identifier& ident, const PutPropertySlot& slot, StructureStubInfo& stubInfo, PutKind putKind)
+void repatchIn(
+    ExecState* exec, JSCell* base, const Identifier& ident, bool wasFound,
+    const PropertySlot& slot, StructureStubInfo& stubInfo)
 {
-    CodeBlock* codeBlock = exec->codeBlock();
-    VM* vm = &exec->vm();
-
-    if (!baseValue.isCell())
-        return false;
-    JSCell* baseCell = baseValue.asCell();
-    Structure* structure = baseCell->structure();
-    Structure* oldStructure = structure->previousID();
-    
-    if (!slot.isCacheable())
-        return false;
-    if (!structure->propertyAccessesAreCacheable())
-        return false;
-
-    // Optimize self access.
-    if (slot.base() == baseValue) {
-        if (slot.type() == PutPropertySlot::NewProperty) {
-            if (structure->isDictionary())
-                return false;
-            
-            // Skip optimizing the case where we need a realloc, if we don't have
-            // enough registers to make it happen.
-            if (GPRInfo::numberOfRegisters < 6
-                && oldStructure->outOfLineCapacity() != structure->outOfLineCapacity()
-                && oldStructure->outOfLineCapacity())
-                return false;
-            
-            // Skip optimizing the case where we need realloc, and the structure has
-            // indexing storage.
-            if (oldStructure->couldHaveIndexingHeader())
-                return false;
-            
-            if (normalizePrototypeChain(exec, baseCell) == InvalidPrototypeChain)
-                return false;
-            
-            StructureChain* prototypeChain = structure->prototypeChain(exec);
-            
-            emitPutTransitionStub(
-                exec, baseValue, ident, slot, stubInfo, putKind,
-                structure, oldStructure, prototypeChain,
-                stubInfo.callReturnLocation.labelAtOffset(stubInfo.patch.deltaCallToSlowCase),
-                stubInfo.stubRoutine);
-            
-            RepatchBuffer repatchBuffer(codeBlock);
-            repatchBuffer.relink(
-                stubInfo.callReturnLocation.jumpAtOffset(
-                    stubInfo.patch.deltaCallToJump),
-                CodeLocationLabel(stubInfo.stubRoutine->code().code()));
-            repatchCall(repatchBuffer, stubInfo.callReturnLocation, appropriateListBuildingPutByIdFunction(slot, putKind));
-            
-            stubInfo.initPutByIdTransition(*vm, codeBlock->ownerExecutable(), oldStructure, structure, prototypeChain, putKind == Direct);
-            
-            return true;
-        }
-
-        if (!MacroAssembler::isPtrAlignedAddressOffset(offsetRelativeToPatchedStorage(slot.cachedOffset())))
-            return false;
-
-        repatchByIdSelfAccess(*vm, codeBlock, stubInfo, structure, ident, slot.cachedOffset(), appropriateListBuildingPutByIdFunction(slot, putKind), false);
-        stubInfo.initPutByIdReplace(*vm, codeBlock->ownerExecutable(), structure);
-        return true;
-    }
-
-    return false;
+    SuperSamplerScope superSamplerScope(false);
+    if (tryRepatchIn(exec, base, ident, wasFound, slot, stubInfo) == GiveUpOnCache)
+        ftlThunkAwareRepatchCall(exec->codeBlock(), stubInfo.slowPathCallLocation(), operationIn);
 }
 
-void repatchPutByID(ExecState* exec, JSValue baseValue, const Identifier& propertyName, const PutPropertySlot& slot, StructureStubInfo& stubInfo, PutKind putKind)
+static void linkSlowFor(VM*, CallLinkInfo& callLinkInfo, MacroAssemblerCodeRef codeRef)
 {
-    GCSafeConcurrentJITLocker locker(exec->codeBlock()->m_lock, exec->vm().heap);
-    
-    bool cached = tryCachePutByID(exec, baseValue, propertyName, slot, stubInfo, putKind);
-    if (!cached)
-        repatchCall(exec->codeBlock(), stubInfo.callReturnLocation, appropriateGenericPutByIdFunction(slot, putKind));
+    MacroAssembler::repatchNearCall(callLinkInfo.callReturnLocation(), CodeLocationLabel(codeRef.code()));
 }
 
-static bool tryBuildPutByIdList(ExecState* exec, JSValue baseValue, const Identifier& propertyName, const PutPropertySlot& slot, StructureStubInfo& stubInfo, PutKind putKind)
+static void linkSlowFor(VM* vm, CallLinkInfo& callLinkInfo, ThunkGenerator generator)
 {
-    CodeBlock* codeBlock = exec->codeBlock();
-    VM* vm = &exec->vm();
-
-    if (!baseValue.isCell())
-        return false;
-    JSCell* baseCell = baseValue.asCell();
-    Structure* structure = baseCell->structure();
-    Structure* oldStructure = structure->previousID();
-    
-    if (!slot.isCacheable())
-        return false;
-    if (!structure->propertyAccessesAreCacheable())
-        return false;
-
-    // Optimize self access.
-    if (slot.base() == baseValue) {
-        PolymorphicPutByIdList* list;
-        RefPtr<JITStubRoutine> stubRoutine;
-        
-        if (slot.type() == PutPropertySlot::NewProperty) {
-            if (structure->isDictionary())
-                return false;
-            
-            // Skip optimizing the case where we need a realloc, if we don't have
-            // enough registers to make it happen.
-            if (GPRInfo::numberOfRegisters < 6
-                && oldStructure->outOfLineCapacity() != structure->outOfLineCapacity()
-                && oldStructure->outOfLineCapacity())
-                return false;
-            
-            // Skip optimizing the case where we need realloc, and the structure has
-            // indexing storage.
-            if (oldStructure->couldHaveIndexingHeader())
-                return false;
-            
-            if (normalizePrototypeChain(exec, baseCell) == InvalidPrototypeChain)
-                return false;
-            
-            StructureChain* prototypeChain = structure->prototypeChain(exec);
-            
-            // We're now committed to creating the stub. Mogrify the meta-data accordingly.
-            list = PolymorphicPutByIdList::from(
-                putKind, stubInfo,
-                stubInfo.callReturnLocation.labelAtOffset(stubInfo.patch.deltaCallToSlowCase));
-            
-            emitPutTransitionStub(
-                exec, baseValue, propertyName, slot, stubInfo, putKind,
-                structure, oldStructure, prototypeChain,
-                CodeLocationLabel(list->currentSlowPathTarget()),
-                stubRoutine);
-            
-            list->addAccess(
-                PutByIdAccess::transition(
-                    *vm, codeBlock->ownerExecutable(),
-                    oldStructure, structure, prototypeChain,
-                    stubRoutine));
-        } else {
-            // We're now committed to creating the stub. Mogrify the meta-data accordingly.
-            list = PolymorphicPutByIdList::from(
-                putKind, stubInfo,
-                stubInfo.callReturnLocation.labelAtOffset(stubInfo.patch.deltaCallToSlowCase));
-            
-            emitPutReplaceStub(
-                exec, baseValue, propertyName, slot, stubInfo, putKind,
-                structure, CodeLocationLabel(list->currentSlowPathTarget()), stubRoutine);
-            
-            list->addAccess(
-                PutByIdAccess::replace(
-                    *vm, codeBlock->ownerExecutable(),
-                    structure, stubRoutine));
-        }
-        
-        RepatchBuffer repatchBuffer(codeBlock);
-        repatchBuffer.relink(stubInfo.callReturnLocation.jumpAtOffset(stubInfo.patch.deltaCallToJump), CodeLocationLabel(stubRoutine->code().code()));
-        
-        if (list->isFull())
-            repatchCall(repatchBuffer, stubInfo.callReturnLocation, appropriateGenericPutByIdFunction(slot, putKind));
-        
-        return true;
-    }
-    
-    return false;
+    linkSlowFor(vm, callLinkInfo, vm->getCTIStub(generator));
 }
 
-void buildPutByIdList(ExecState* exec, JSValue baseValue, const Identifier& propertyName, const PutPropertySlot& slot, StructureStubInfo& stubInfo, PutKind putKind)
+static void linkSlowFor(VM* vm, CallLinkInfo& callLinkInfo)
 {
-    GCSafeConcurrentJITLocker locker(exec->codeBlock()->m_lock, exec->vm().heap);
-    
-    bool cached = tryBuildPutByIdList(exec, baseValue, propertyName, slot, stubInfo, putKind);
-    if (!cached)
-        repatchCall(exec->codeBlock(), stubInfo.callReturnLocation, appropriateGenericPutByIdFunction(slot, putKind));
+    MacroAssemblerCodeRef virtualThunk = virtualThunkFor(vm, callLinkInfo);
+    linkSlowFor(vm, callLinkInfo, virtualThunk);
+    callLinkInfo.setSlowStub(createJITStubRoutine(virtualThunk, *vm, nullptr, true));
 }
 
-static bool tryRepatchIn(
-    ExecState* exec, JSCell* base, const Identifier& ident, bool wasFound,
-    const PropertySlot& slot, StructureStubInfo& stubInfo)
+static bool isWebAssemblyToJSCallee(VM& vm, JSCell* callee)
 {
-    if (!base->structure()->propertyAccessesAreCacheable())
-        return false;
-    
-    if (wasFound) {
-        if (!slot.isCacheable())
-            return false;
-    }
-    
-    CodeBlock* codeBlock = exec->codeBlock();
-    VM* vm = &exec->vm();
-    Structure* structure = base->structure();
-    
-    PropertyOffset offsetIgnored;
-    size_t count = normalizePrototypeChainForChainAccess(exec, base, wasFound ? slot.slotBase() : JSValue(), ident, offsetIgnored);
-    if (count == InvalidPrototypeChain)
-        return false;
-    
-    PolymorphicAccessStructureList* polymorphicStructureList;
-    int listIndex;
-    
-    CodeLocationLabel successLabel = stubInfo.callReturnLocation.labelAtOffset(stubInfo.patch.deltaCallToDone);
-    CodeLocationLabel slowCaseLabel;
-    
-    if (stubInfo.accessType == access_unset) {
-        polymorphicStructureList = new PolymorphicAccessStructureList();
-        stubInfo.initInList(polymorphicStructureList, 0);
-        slowCaseLabel = stubInfo.callReturnLocation.labelAtOffset(
-            stubInfo.patch.deltaCallToSlowCase);
-        listIndex = 0;
-    } else {
-        RELEASE_ASSERT(stubInfo.accessType == access_in_list);
-        polymorphicStructureList = stubInfo.u.inList.structureList;
-        listIndex = stubInfo.u.inList.listSize;
-        slowCaseLabel = CodeLocationLabel(polymorphicStructureList->list[listIndex - 1].stubRoutine->code().code());
-        
-        if (listIndex == POLYMORPHIC_LIST_CACHE_SIZE)
-            return false;
-    }
-    
-    StructureChain* chain = structure->prototypeChain(exec);
-    RefPtr<JITStubRoutine> stubRoutine;
-    
-    {
-        GPRReg baseGPR = static_cast<GPRReg>(stubInfo.patch.baseGPR);
-        GPRReg resultGPR = static_cast<GPRReg>(stubInfo.patch.valueGPR);
-        GPRReg scratchGPR = TempRegisterSet(stubInfo.patch.usedRegisters).getFreeGPR();
-        
-        CCallHelpers stubJit(vm);
-        
-        bool needToRestoreScratch;
-        if (scratchGPR == InvalidGPRReg) {
-            scratchGPR = AssemblyHelpers::selectScratchGPR(baseGPR, resultGPR);
-            stubJit.pushToSave(scratchGPR);
-            needToRestoreScratch = true;
-        } else
-            needToRestoreScratch = false;
-        
-        MacroAssembler::JumpList failureCases;
-        failureCases.append(stubJit.branchPtr(
-            MacroAssembler::NotEqual,
-            MacroAssembler::Address(baseGPR, JSCell::structureOffset()),
-            MacroAssembler::TrustedImmPtr(structure)));
-
-        CodeBlock* codeBlock = exec->codeBlock();
-        if (structure->typeInfo().newImpurePropertyFiresWatchpoints())
-            vm->registerWatchpointForImpureProperty(ident, stubInfo.addWatchpoint(codeBlock));
-
-        Structure* currStructure = structure;
-        WriteBarrier<Structure>* it = chain->head();
-        for (unsigned i = 0; i < count; ++i, ++it) {
-            JSObject* prototype = asObject(currStructure->prototypeForLookup(exec));
-            Structure* protoStructure = prototype->structure();
-            addStructureTransitionCheck(
-                prototype, protoStructure, exec->codeBlock(), stubInfo, stubJit,
-                failureCases, scratchGPR);
-            if (protoStructure->typeInfo().newImpurePropertyFiresWatchpoints())
-                vm->registerWatchpointForImpureProperty(ident, stubInfo.addWatchpoint(codeBlock));
-            currStructure = it->get();
-        }
-        
-#if USE(JSVALUE64)
-        stubJit.move(MacroAssembler::TrustedImm64(JSValue::encode(jsBoolean(wasFound))), resultGPR);
+#if ENABLE(WEBASSEMBLY)
+    // The WebAssembly -> JS stub sets it caller frame's callee to a singleton which lives on the VM.
+    return callee == vm.webAssemblyToJSCallee.get();
 #else
-        stubJit.move(MacroAssembler::TrustedImm32(wasFound), resultGPR);
-#endif
-        
-        MacroAssembler::Jump success, fail;
-        
-        emitRestoreScratch(stubJit, needToRestoreScratch, scratchGPR, success, fail, failureCases);
-        
-        LinkBuffer patchBuffer(*vm, &stubJit, exec->codeBlock());
-
-        linkRestoreScratch(patchBuffer, needToRestoreScratch, success, fail, failureCases, successLabel, slowCaseLabel);
-        
-        stubRoutine = FINALIZE_CODE_FOR_DFG_STUB(
-            patchBuffer,
-            ("DFG In (found = %s) stub for %s, return point %p",
-                wasFound ? "yes" : "no", toCString(*exec->codeBlock()).data(),
-                successLabel.executableAddress()));
-    }
-    
-    polymorphicStructureList->list[listIndex].set(*vm, codeBlock->ownerExecutable(), stubRoutine, structure, true);
-    stubInfo.u.inList.listSize++;
-    
-    RepatchBuffer repatchBuffer(codeBlock);
-    repatchBuffer.relink(stubInfo.callReturnLocation.jumpAtOffset(stubInfo.patch.deltaCallToJump), CodeLocationLabel(stubRoutine->code().code()));
-    
-    return listIndex < (POLYMORPHIC_LIST_CACHE_SIZE - 1);
+    UNUSED_PARAM(vm);
+    UNUSED_PARAM(callee);
+    return false;
+#endif // ENABLE(WEBASSEMBLY)
 }
 
-void repatchIn(
-    ExecState* exec, JSCell* base, const Identifier& ident, bool wasFound,
-    const PropertySlot& slot, StructureStubInfo& stubInfo)
+static JSCell* webAssemblyOwner(VM& vm)
 {
-    if (tryRepatchIn(exec, base, ident, wasFound, slot, stubInfo))
-        return;
-    repatchCall(exec->codeBlock(), stubInfo.callReturnLocation, operationIn);
+#if ENABLE(WEBASSEMBLY)
+    // Each WebAssembly.Instance shares the stubs from their WebAssembly.Module, which are therefore the appropriate owner.
+    return vm.topJSWebAssemblyInstance->module();
+#else
+    UNUSED_PARAM(vm);
+    RELEASE_ASSERT_NOT_REACHED();
+    return nullptr;
+#endif // ENABLE(WEBASSEMBLY)
 }
 
-static void linkSlowFor(RepatchBuffer& repatchBuffer, VM* vm, CallLinkInfo& callLinkInfo, CodeSpecializationKind kind)
+void linkFor(
+    ExecState* exec, CallLinkInfo& callLinkInfo, CodeBlock* calleeCodeBlock,
+    JSFunction* callee, MacroAssemblerCodePtr codePtr)
 {
-    if (kind == CodeForCall) {
-        repatchBuffer.relink(callLinkInfo.callReturnLocation, vm->getCTIStub(virtualCallThunkGenerator).code());
+    ASSERT(!callLinkInfo.stub());
+
+    CallFrame* callerFrame = exec->callerFrame();
+    VM& vm = callerFrame->vm();
+    CodeBlock* callerCodeBlock = callerFrame->codeBlock();
+
+    // WebAssembly -> JS stubs don't have a valid CodeBlock.
+    JSCell* owner = isWebAssemblyToJSCallee(vm, callerFrame->callee()) ? webAssemblyOwner(vm) : callerCodeBlock;
+    ASSERT(owner);
+
+    ASSERT(!callLinkInfo.isLinked());
+    callLinkInfo.setCallee(vm, owner, callee);
+    callLinkInfo.setLastSeenCallee(vm, owner, callee);
+    if (shouldDumpDisassemblyFor(callerCodeBlock))
+        dataLog("Linking call in ", *callerCodeBlock, " at ", callLinkInfo.codeOrigin(), " to ", pointerDump(calleeCodeBlock), ", entrypoint at ", codePtr, "\n");
+    MacroAssembler::repatchNearCall(callLinkInfo.hotPathOther(), CodeLocationLabel(codePtr));
+
+    if (calleeCodeBlock)
+        calleeCodeBlock->linkIncomingCall(callerFrame, &callLinkInfo);
+
+    if (callLinkInfo.specializationKind() == CodeForCall && callLinkInfo.allowStubs()) {
+        linkSlowFor(&vm, callLinkInfo, linkPolymorphicCallThunkGenerator);
         return;
     }
-    ASSERT(kind == CodeForConstruct);
-    repatchBuffer.relink(callLinkInfo.callReturnLocation, vm->getCTIStub(virtualConstructThunkGenerator).code());
+    
+    linkSlowFor(&vm, callLinkInfo);
 }
 
-void linkFor(ExecState* exec, CallLinkInfo& callLinkInfo, CodeBlock* calleeCodeBlock, JSFunction* callee, MacroAssemblerCodePtr codePtr, CodeSpecializationKind kind)
+void linkDirectFor(
+    ExecState* exec, CallLinkInfo& callLinkInfo, CodeBlock* calleeCodeBlock,
+    MacroAssemblerCodePtr codePtr)
 {
-    ASSERT(!callLinkInfo.stub);
-    
-    // If you're being call-linked from a DFG caller then you obviously didn't get inlined.
-    if (calleeCodeBlock)
-        calleeCodeBlock->m_shouldAlwaysBeInlined = false;
+    ASSERT(!callLinkInfo.stub());
     
-    CodeBlock* callerCodeBlock = exec->callerFrame()->codeBlock();
+    CodeBlock* callerCodeBlock = exec->codeBlock();
+
     VM* vm = callerCodeBlock->vm();
     
-    RepatchBuffer repatchBuffer(callerCodeBlock);
-    
     ASSERT(!callLinkInfo.isLinked());
-    callLinkInfo.callee.set(exec->callerFrame()->vm(), callLinkInfo.hotPathBegin, callerCodeBlock->ownerExecutable(), callee);
-    callLinkInfo.lastSeenCallee.set(exec->callerFrame()->vm(), callerCodeBlock->ownerExecutable(), callee);
-    repatchBuffer.relink(callLinkInfo.hotPathOther, codePtr);
+    callLinkInfo.setCodeBlock(*vm, callerCodeBlock, jsCast<FunctionCodeBlock*>(calleeCodeBlock));
+    if (shouldDumpDisassemblyFor(callerCodeBlock))
+        dataLog("Linking call in ", *callerCodeBlock, " at ", callLinkInfo.codeOrigin(), " to ", pointerDump(calleeCodeBlock), ", entrypoint at ", codePtr, "\n");
+    if (callLinkInfo.callType() == CallLinkInfo::DirectTailCall)
+        MacroAssembler::repatchJumpToNop(callLinkInfo.patchableJump());
+    MacroAssembler::repatchNearCall(callLinkInfo.hotPathOther(), CodeLocationLabel(codePtr));
     
     if (calleeCodeBlock)
-        calleeCodeBlock->linkIncomingCall(exec->callerFrame(), &callLinkInfo);
-    
-    if (kind == CodeForCall) {
-        repatchBuffer.relink(callLinkInfo.callReturnLocation, vm->getCTIStub(linkClosureCallThunkGenerator).code());
-        return;
-    }
-    
-    ASSERT(kind == CodeForConstruct);
-    linkSlowFor(repatchBuffer, vm, callLinkInfo, CodeForConstruct);
+        calleeCodeBlock->linkIncomingCall(exec, &callLinkInfo);
 }
 
-void linkSlowFor(ExecState* exec, CallLinkInfo& callLinkInfo, CodeSpecializationKind kind)
+void linkSlowFor(
+    ExecState* exec, CallLinkInfo& callLinkInfo)
 {
     CodeBlock* callerCodeBlock = exec->callerFrame()->codeBlock();
     VM* vm = callerCodeBlock->vm();
     
-    RepatchBuffer repatchBuffer(callerCodeBlock);
+    linkSlowFor(vm, callLinkInfo);
+}
+
+static void revertCall(VM* vm, CallLinkInfo& callLinkInfo, MacroAssemblerCodeRef codeRef)
+{
+    if (callLinkInfo.isDirect()) {
+        callLinkInfo.clearCodeBlock();
+        if (callLinkInfo.callType() == CallLinkInfo::DirectTailCall)
+            MacroAssembler::repatchJump(callLinkInfo.patchableJump(), callLinkInfo.slowPathStart());
+        else
+            MacroAssembler::repatchNearCall(callLinkInfo.hotPathOther(), callLinkInfo.slowPathStart());
+    } else {
+        MacroAssembler::revertJumpReplacementToBranchPtrWithPatch(
+            MacroAssembler::startOfBranchPtrWithPatchOnRegister(callLinkInfo.hotPathBegin()),
+            static_cast<MacroAssembler::RegisterID>(callLinkInfo.calleeGPR()), 0);
+        linkSlowFor(vm, callLinkInfo, codeRef);
+        callLinkInfo.clearCallee();
+    }
+    callLinkInfo.clearSeen();
+    callLinkInfo.clearStub();
+    callLinkInfo.clearSlowStub();
+    if (callLinkInfo.isOnList())
+        callLinkInfo.remove();
+}
+
+void unlinkFor(VM& vm, CallLinkInfo& callLinkInfo)
+{
+    if (Options::dumpDisassembly())
+        dataLog("Unlinking call at ", callLinkInfo.hotPathOther(), "\n");
     
-    linkSlowFor(repatchBuffer, vm, callLinkInfo, kind);
+    revertCall(&vm, callLinkInfo, vm.getCTIStub(linkCallThunkGenerator));
+}
+
+void linkVirtualFor(ExecState* exec, CallLinkInfo& callLinkInfo)
+{
+    CallFrame* callerFrame = exec->callerFrame();
+    VM& vm = callerFrame->vm();
+    CodeBlock* callerCodeBlock = callerFrame->codeBlock();
+
+    if (shouldDumpDisassemblyFor(callerCodeBlock))
+        dataLog("Linking virtual call at ", *callerCodeBlock, " ", callerFrame->codeOrigin(), "\n");
+
+    MacroAssemblerCodeRef virtualThunk = virtualThunkFor(&vm, callLinkInfo);
+    revertCall(&vm, callLinkInfo, virtualThunk);
+    callLinkInfo.setSlowStub(createJITStubRoutine(virtualThunk, vm, nullptr, true));
 }
 
-void linkClosureCall(ExecState* exec, CallLinkInfo& callLinkInfo, CodeBlock* calleeCodeBlock, Structure* structure, ExecutableBase* executable, MacroAssemblerCodePtr codePtr)
+namespace {
+struct CallToCodePtr {
+    CCallHelpers::Call call;
+    MacroAssemblerCodePtr codePtr;
+};
+} // annonymous namespace
+
+void linkPolymorphicCall(
+    ExecState* exec, CallLinkInfo& callLinkInfo, CallVariant newVariant)
 {
-    ASSERT(!callLinkInfo.stub);
+    RELEASE_ASSERT(callLinkInfo.allowStubs());
     
-    CodeBlock* callerCodeBlock = exec->callerFrame()->codeBlock();
-    VM* vm = callerCodeBlock->vm();
+    // Currently we can't do anything for non-function callees.
+    // https://bugs.webkit.org/show_bug.cgi?id=140685
+    if (!newVariant || !newVariant.executable()) {
+        linkVirtualFor(exec, callLinkInfo);
+        return;
+    }
+
+    CallFrame* callerFrame = exec->callerFrame();
+    VM& vm = callerFrame->vm();
+    CodeBlock* callerCodeBlock = callerFrame->codeBlock();
+    bool isWebAssembly = isWebAssemblyToJSCallee(vm, callerFrame->callee());
+
+    // WebAssembly -> JS stubs don't have a valid CodeBlock.
+    JSCell* owner = isWebAssembly ? webAssemblyOwner(vm) : callerCodeBlock;
+    ASSERT(owner);
+
+    CallVariantList list;
+    if (PolymorphicCallStubRoutine* stub = callLinkInfo.stub())
+        list = stub->variants();
+    else if (JSFunction* oldCallee = callLinkInfo.callee())
+        list = CallVariantList{ CallVariant(oldCallee) };
+    
+    list = variantListWithVariant(list, newVariant);
+
+    // If there are any closure calls then it makes sense to treat all of them as closure calls.
+    // This makes switching on callee cheaper. It also produces profiling that's easier on the DFG;
+    // the DFG doesn't really want to deal with a combination of closure and non-closure callees.
+    bool isClosureCall = false;
+    for (CallVariant variant : list)  {
+        if (variant.isClosureCall()) {
+            list = despecifiedVariantList(list);
+            isClosureCall = true;
+            break;
+        }
+    }
     
-    GPRReg calleeGPR = static_cast<GPRReg>(callLinkInfo.calleeGPR);
+    if (isClosureCall)
+        callLinkInfo.setHasSeenClosure();
+    
+    Vector<PolymorphicCallCase> callCases;
+    
+    // Figure out what our cases are.
+    for (CallVariant variant : list) {
+        CodeBlock* codeBlock;
+        if (isWebAssembly || variant.executable()->isHostFunction())
+            codeBlock = nullptr;
+        else {
+            ExecutableBase* executable = variant.executable();
+            codeBlock = jsCast<FunctionExecutable*>(executable)->codeBlockForCall();
+            // If we cannot handle a callee, either because we don't have a CodeBlock or because arity mismatch,
+            // assume that it's better for this whole thing to be a virtual call.
+            if (!codeBlock || exec->argumentCountIncludingThis() < static_cast<size_t>(codeBlock->numParameters()) || callLinkInfo.isVarargs()) {
+                linkVirtualFor(exec, callLinkInfo);
+                return;
+            }
+        }
+        
+        callCases.append(PolymorphicCallCase(variant, codeBlock));
+    }
     
-    CCallHelpers stubJit(vm, callerCodeBlock);
+    // If we are over the limit, just use a normal virtual call.
+    unsigned maxPolymorphicCallVariantListSize;
+    if (isWebAssembly)
+        maxPolymorphicCallVariantListSize = Options::maxPolymorphicCallVariantListSizeForWebAssemblyToJS();
+    else if (callerCodeBlock->jitType() == JITCode::topTierJIT())
+        maxPolymorphicCallVariantListSize = Options::maxPolymorphicCallVariantListSizeForTopTier();
+    else
+        maxPolymorphicCallVariantListSize = Options::maxPolymorphicCallVariantListSize();
+
+    if (list.size() > maxPolymorphicCallVariantListSize) {
+        linkVirtualFor(exec, callLinkInfo);
+        return;
+    }
+    
+    GPRReg calleeGPR = static_cast<GPRReg>(callLinkInfo.calleeGPR());
+    
+    CCallHelpers stubJit(&vm, callerCodeBlock);
     
     CCallHelpers::JumpList slowPath;
     
+    std::unique_ptr<CallFrameShuffler> frameShuffler;
+    if (callLinkInfo.frameShuffleData()) {
+        ASSERT(callLinkInfo.isTailCall());
+        frameShuffler = std::make_unique<CallFrameShuffler>(stubJit, *callLinkInfo.frameShuffleData());
+#if USE(JSVALUE32_64)
+        // We would have already checked that the callee is a cell, and we can
+        // use the additional register this buys us.
+        frameShuffler->assumeCalleeIsCell();
+#endif
+        frameShuffler->lockGPR(calleeGPR);
+    }
+    GPRReg comparisonValueGPR;
+    
+    if (isClosureCall) {
+        GPRReg scratchGPR;
+        if (frameShuffler)
+            scratchGPR = frameShuffler->acquireGPR();
+        else
+            scratchGPR = AssemblyHelpers::selectScratchGPR(calleeGPR);
+        // Verify that we have a function and stash the executable in scratchGPR.
+
 #if USE(JSVALUE64)
-    // We can safely clobber everything except the calleeGPR. We can't rely on tagMaskRegister
-    // being set. So we do this the hard way.
-    GPRReg scratch = AssemblyHelpers::selectScratchGPR(calleeGPR);
-    stubJit.move(MacroAssembler::TrustedImm64(TagMask), scratch);
-    slowPath.append(stubJit.branchTest64(CCallHelpers::NonZero, calleeGPR, scratch));
+        slowPath.append(stubJit.branchTest64(CCallHelpers::NonZero, calleeGPR, GPRInfo::tagMaskRegister));
 #else
-    // We would have already checked that the callee is a cell.
+        // We would have already checked that the callee is a cell.
 #endif
     
-    slowPath.append(
-        stubJit.branchPtr(
-            CCallHelpers::NotEqual,
-            CCallHelpers::Address(calleeGPR, JSCell::structureOffset()),
-            CCallHelpers::TrustedImmPtr(structure)));
+        slowPath.append(
+            stubJit.branch8(
+                CCallHelpers::NotEqual,
+                CCallHelpers::Address(calleeGPR, JSCell::typeInfoTypeOffset()),
+                CCallHelpers::TrustedImm32(JSFunctionType)));
     
-    slowPath.append(
-        stubJit.branchPtr(
-            CCallHelpers::NotEqual,
+        stubJit.loadPtr(
             CCallHelpers::Address(calleeGPR, JSFunction::offsetOfExecutable()),
-            CCallHelpers::TrustedImmPtr(executable)));
+            scratchGPR);
+        
+        comparisonValueGPR = scratchGPR;
+    } else
+        comparisonValueGPR = calleeGPR;
+    
+    Vector<int64_t> caseValues(callCases.size());
+    Vector<CallToCodePtr> calls(callCases.size());
+    std::unique_ptr<uint32_t[]> fastCounts;
+    
+    if (!isWebAssembly && callerCodeBlock->jitType() != JITCode::topTierJIT())
+        fastCounts = std::make_unique<uint32_t[]>(callCases.size());
+    
+    for (size_t i = 0; i < callCases.size(); ++i) {
+        if (fastCounts)
+            fastCounts[i] = 0;
+        
+        CallVariant variant = callCases[i].variant();
+        int64_t newCaseValue;
+        if (isClosureCall)
+            newCaseValue = bitwise_cast<intptr_t>(variant.executable());
+        else
+            newCaseValue = bitwise_cast<intptr_t>(variant.function());
+        
+        if (!ASSERT_DISABLED) {
+            for (size_t j = 0; j < i; ++j) {
+                if (caseValues[j] != newCaseValue)
+                    continue;
+
+                dataLog("ERROR: Attempt to add duplicate case value.\n");
+                dataLog("Existing case values: ");
+                CommaPrinter comma;
+                for (size_t k = 0; k < i; ++k)
+                    dataLog(comma, caseValues[k]);
+                dataLog("\n");
+                dataLog("Attempting to add: ", newCaseValue, "\n");
+                dataLog("Variant list: ", listDump(callCases), "\n");
+                RELEASE_ASSERT_NOT_REACHED();
+            }
+        }
+        
+        caseValues[i] = newCaseValue;
+    }
     
-    stubJit.loadPtr(
-        CCallHelpers::Address(calleeGPR, JSFunction::offsetOfScopeChain()),
-        GPRInfo::returnValueGPR);
+    GPRReg fastCountsBaseGPR;
+    if (frameShuffler)
+        fastCountsBaseGPR = frameShuffler->acquireGPR();
+    else {
+        fastCountsBaseGPR =
+            AssemblyHelpers::selectScratchGPR(calleeGPR, comparisonValueGPR, GPRInfo::regT3);
+    }
+    stubJit.move(CCallHelpers::TrustedImmPtr(fastCounts.get()), fastCountsBaseGPR);
+    if (!frameShuffler && callLinkInfo.isTailCall())
+        stubJit.emitRestoreCalleeSaves();
+    BinarySwitch binarySwitch(comparisonValueGPR, caseValues, BinarySwitch::IntPtr);
+    CCallHelpers::JumpList done;
+    while (binarySwitch.advance(stubJit)) {
+        size_t caseIndex = binarySwitch.caseIndex();
+        
+        CallVariant variant = callCases[caseIndex].variant();
+        
+        ASSERT(variant.executable()->hasJITCodeForCall());
+        MacroAssemblerCodePtr codePtr =
+            variant.executable()->generatedJITCodeForCall()->addressForCall(ArityCheckNotRequired);
+        
+        if (fastCounts) {
+            stubJit.add32(
+                CCallHelpers::TrustedImm32(1),
+                CCallHelpers::Address(fastCountsBaseGPR, caseIndex * sizeof(uint32_t)));
+        }
+        if (frameShuffler) {
+            CallFrameShuffler(stubJit, frameShuffler->snapshot()).prepareForTailCall();
+            calls[caseIndex].call = stubJit.nearTailCall();
+        } else if (callLinkInfo.isTailCall()) {
+            stubJit.prepareForTailCallSlow();
+            calls[caseIndex].call = stubJit.nearTailCall();
+        } else
+            calls[caseIndex].call = stubJit.nearCall();
+        calls[caseIndex].codePtr = codePtr;
+        done.append(stubJit.jump());
+    }
+    
+    slowPath.link(&stubJit);
+    binarySwitch.fallThrough().link(&stubJit);
 
-#if USE(JSVALUE64)
-    stubJit.store64(
-        GPRInfo::returnValueGPR,
-        CCallHelpers::Address(GPRInfo::callFrameRegister, static_cast<ptrdiff_t>(sizeof(Register) * JSStack::ScopeChain)));
+    if (frameShuffler) {
+        frameShuffler->releaseGPR(calleeGPR);
+        frameShuffler->releaseGPR(comparisonValueGPR);
+        frameShuffler->releaseGPR(fastCountsBaseGPR);
+#if USE(JSVALUE32_64)
+        frameShuffler->setCalleeJSValueRegs(JSValueRegs(GPRInfo::regT1, GPRInfo::regT0));
 #else
-    stubJit.storePtr(
-        GPRInfo::returnValueGPR,
-        CCallHelpers::Address(GPRInfo::callFrameRegister, static_cast<ptrdiff_t>(sizeof(Register) * JSStack::ScopeChain) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.payload)));
-    stubJit.store32(
-        CCallHelpers::TrustedImm32(JSValue::CellTag),
-        CCallHelpers::Address(GPRInfo::callFrameRegister, static_cast<ptrdiff_t>(sizeof(Register) * JSStack::ScopeChain) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.tag)));
+        frameShuffler->setCalleeJSValueRegs(JSValueRegs(GPRInfo::regT0));
 #endif
-    
-    AssemblyHelpers::Call call = stubJit.nearCall();
-    AssemblyHelpers::Jump done = stubJit.jump();
-    
-    slowPath.link(&stubJit);
-    stubJit.move(calleeGPR, GPRInfo::regT0);
+        frameShuffler->prepareForSlowPath();
+    } else {
+        stubJit.move(calleeGPR, GPRInfo::regT0);
 #if USE(JSVALUE32_64)
-    stubJit.move(CCallHelpers::TrustedImm32(JSValue::CellTag), GPRInfo::regT1);
+        stubJit.move(CCallHelpers::TrustedImm32(JSValue::CellTag), GPRInfo::regT1);
 #endif
-    stubJit.move(CCallHelpers::TrustedImmPtr(callLinkInfo.callReturnLocation.executableAddress()), GPRInfo::nonArgGPR2);
-    stubJit.restoreReturnAddressBeforeReturn(GPRInfo::nonArgGPR2);
-    AssemblyHelpers::Jump slow = stubJit.jump();
-    
-    LinkBuffer patchBuffer(*vm, &stubJit, callerCodeBlock);
-    
-    patchBuffer.link(call, FunctionPtr(codePtr.executableAddress()));
-    patchBuffer.link(done, callLinkInfo.callReturnLocation.labelAtOffset(0));
-    patchBuffer.link(slow, CodeLocationLabel(vm->getCTIStub(virtualCallThunkGenerator).code()));
-    
-    RefPtr<ClosureCallStubRoutine> stubRoutine = adoptRef(new ClosureCallStubRoutine(
-        FINALIZE_DFG_CODE(
-            patchBuffer,
-            ("DFG closure call stub for %s, return point %p, target %p (%s)",
-                toCString(*callerCodeBlock).data(), callLinkInfo.callReturnLocation.labelAtOffset(0).executableAddress(),
-                codePtr.executableAddress(), toCString(pointerDump(calleeCodeBlock)).data())),
-        *vm, callerCodeBlock->ownerExecutable(), structure, executable, callLinkInfo.codeOrigin));
+    }
+    stubJit.move(CCallHelpers::TrustedImmPtr(&callLinkInfo), GPRInfo::regT2);
+    stubJit.move(CCallHelpers::TrustedImmPtr(callLinkInfo.callReturnLocation().executableAddress()), GPRInfo::regT4);
     
-    RepatchBuffer repatchBuffer(callerCodeBlock);
+    stubJit.restoreReturnAddressBeforeReturn(GPRInfo::regT4);
+    AssemblyHelpers::Jump slow = stubJit.jump();
+        
+    LinkBuffer patchBuffer(vm, stubJit, owner, JITCompilationCanFail);
+    if (patchBuffer.didFailToAllocate()) {
+        linkVirtualFor(exec, callLinkInfo);
+        return;
+    }
     
-    repatchBuffer.replaceWithJump(
-        RepatchBuffer::startOfBranchPtrWithPatchOnRegister(callLinkInfo.hotPathBegin),
+    RELEASE_ASSERT(callCases.size() == calls.size());
+    for (CallToCodePtr callToCodePtr : calls) {
+        // Tail call special-casing ensures proper linking on ARM Thumb2, where a tail call jumps to an address
+        // with a non-decorated bottom bit but a normal call calls an address with a decorated bottom bit.
+        bool isTailCall = callToCodePtr.call.isFlagSet(CCallHelpers::Call::Tail);
+        patchBuffer.link(
+            callToCodePtr.call, FunctionPtr(isTailCall ? callToCodePtr.codePtr.dataLocation() : callToCodePtr.codePtr.executableAddress()));
+    }
+    if (isWebAssembly || JITCode::isOptimizingJIT(callerCodeBlock->jitType()))
+        patchBuffer.link(done, callLinkInfo.callReturnLocation().labelAtOffset(0));
+    else
+        patchBuffer.link(done, callLinkInfo.hotPathOther().labelAtOffset(0));
+    patchBuffer.link(slow, CodeLocationLabel(vm.getCTIStub(linkPolymorphicCallThunkGenerator).code()));
+    
+    auto stubRoutine = adoptRef(*new PolymorphicCallStubRoutine(
+        FINALIZE_CODE_FOR(
+            callerCodeBlock, patchBuffer,
+            ("Polymorphic call stub for %s, return point %p, targets %s",
+                isWebAssembly ? "WebAssembly" : toCString(*callerCodeBlock).data(), callLinkInfo.callReturnLocation().labelAtOffset(0).executableAddress(),
+                toCString(listDump(callCases)).data())),
+        vm, owner, exec->callerFrame(), callLinkInfo, callCases,
+        WTFMove(fastCounts)));
+    
+    MacroAssembler::replaceWithJump(
+        MacroAssembler::startOfBranchPtrWithPatchOnRegister(callLinkInfo.hotPathBegin()),
         CodeLocationLabel(stubRoutine->code().code()));
-    linkSlowFor(repatchBuffer, vm, callLinkInfo, CodeForCall);
+    // The original slow path is unreachable on 64-bits, but still
+    // reachable on 32-bits since a non-cell callee will always
+    // trigger the slow path
+    linkSlowFor(&vm, callLinkInfo);
     
-    callLinkInfo.stub = stubRoutine.release();
+    // If there had been a previous stub routine, that one will die as soon as the GC runs and sees
+    // that it's no longer on stack.
+    callLinkInfo.setStub(WTFMove(stubRoutine));
     
-    ASSERT(!calleeCodeBlock || calleeCodeBlock->isIncomingCallAlreadyLinked(&callLinkInfo));
+    // The call link info no longer has a call cache apart from the jump to the polymorphic call
+    // stub.
+    if (callLinkInfo.isOnList())
+        callLinkInfo.remove();
 }
 
-void resetGetByID(RepatchBuffer& repatchBuffer, StructureStubInfo& stubInfo)
+void resetGetByID(CodeBlock* codeBlock, StructureStubInfo& stubInfo, GetByIDKind kind)
 {
-    repatchCall(repatchBuffer, stubInfo.callReturnLocation, operationGetByIdOptimize);
-    CodeLocationDataLabelPtr structureLabel = stubInfo.callReturnLocation.dataLabelPtrAtOffset(-(intptr_t)stubInfo.patch.deltaCheckImmToCall);
-    if (MacroAssembler::canJumpReplacePatchableBranchPtrWithPatch()) {
-        repatchBuffer.revertJumpReplacementToPatchableBranchPtrWithPatch(
-            RepatchBuffer::startOfPatchableBranchPtrWithPatchOnAddress(structureLabel),
-            MacroAssembler::Address(
-                static_cast<MacroAssembler::RegisterID>(stubInfo.patch.baseGPR),
-                JSCell::structureOffset()),
-            reinterpret_cast<void*>(unusedPointer));
-    }
-    repatchBuffer.repatch(structureLabel, reinterpret_cast<void*>(unusedPointer));
-#if USE(JSVALUE64)
-    repatchBuffer.repatch(stubInfo.callReturnLocation.dataLabelCompactAtOffset(stubInfo.patch.deltaCallToLoadOrStore), 0);
-#else
-    repatchBuffer.repatch(stubInfo.callReturnLocation.dataLabelCompactAtOffset(stubInfo.patch.deltaCallToTagLoadOrStore), 0);
-    repatchBuffer.repatch(stubInfo.callReturnLocation.dataLabelCompactAtOffset(stubInfo.patch.deltaCallToPayloadLoadOrStore), 0);
-#endif
-    repatchBuffer.relink(stubInfo.callReturnLocation.jumpAtOffset(stubInfo.patch.deltaCallToJump), stubInfo.callReturnLocation.labelAtOffset(stubInfo.patch.deltaCallToSlowCase));
+    ftlThunkAwareRepatchCall(codeBlock, stubInfo.slowPathCallLocation(), appropriateOptimizingGetByIdFunction(kind));
+    InlineAccess::rewireStubAsJump(*codeBlock->vm(), stubInfo, stubInfo.slowPathStartLocation());
 }
 
-void resetPutByID(RepatchBuffer& repatchBuffer, StructureStubInfo& stubInfo)
+void resetPutByID(CodeBlock* codeBlock, StructureStubInfo& stubInfo)
 {
-    V_JITOperation_ESsiJJI unoptimizedFunction = bitwise_cast<V_JITOperation_ESsiJJI>(readCallTarget(repatchBuffer, stubInfo.callReturnLocation).executableAddress());
+    V_JITOperation_ESsiJJI unoptimizedFunction = bitwise_cast<V_JITOperation_ESsiJJI>(readCallTarget(codeBlock, stubInfo.slowPathCallLocation()).executableAddress());
     V_JITOperation_ESsiJJI optimizedFunction;
-    if (unoptimizedFunction == operationPutByIdStrict || unoptimizedFunction == operationPutByIdStrictBuildList)
+    if (unoptimizedFunction == operationPutByIdStrict || unoptimizedFunction == operationPutByIdStrictOptimize)
         optimizedFunction = operationPutByIdStrictOptimize;
-    else if (unoptimizedFunction == operationPutByIdNonStrict || unoptimizedFunction == operationPutByIdNonStrictBuildList)
+    else if (unoptimizedFunction == operationPutByIdNonStrict || unoptimizedFunction == operationPutByIdNonStrictOptimize)
         optimizedFunction = operationPutByIdNonStrictOptimize;
-    else if (unoptimizedFunction == operationPutByIdDirectStrict || unoptimizedFunction == operationPutByIdDirectStrictBuildList)
+    else if (unoptimizedFunction == operationPutByIdDirectStrict || unoptimizedFunction == operationPutByIdDirectStrictOptimize)
         optimizedFunction = operationPutByIdDirectStrictOptimize;
     else {
-        ASSERT(unoptimizedFunction == operationPutByIdDirectNonStrict || unoptimizedFunction == operationPutByIdDirectNonStrictBuildList);
+        ASSERT(unoptimizedFunction == operationPutByIdDirectNonStrict || unoptimizedFunction == operationPutByIdDirectNonStrictOptimize);
         optimizedFunction = operationPutByIdDirectNonStrictOptimize;
     }
-    repatchCall(repatchBuffer, stubInfo.callReturnLocation, optimizedFunction);
-    CodeLocationDataLabelPtr structureLabel = stubInfo.callReturnLocation.dataLabelPtrAtOffset(-(intptr_t)stubInfo.patch.deltaCheckImmToCall);
-    if (MacroAssembler::canJumpReplacePatchableBranchPtrWithPatch()) {
-        repatchBuffer.revertJumpReplacementToPatchableBranchPtrWithPatch(
-            RepatchBuffer::startOfPatchableBranchPtrWithPatchOnAddress(structureLabel),
-            MacroAssembler::Address(
-                static_cast<MacroAssembler::RegisterID>(stubInfo.patch.baseGPR),
-                JSCell::structureOffset()),
-            reinterpret_cast<void*>(unusedPointer));
-    }
-    repatchBuffer.repatch(structureLabel, reinterpret_cast<void*>(unusedPointer));
-#if USE(JSVALUE64)
-    repatchBuffer.repatch(stubInfo.callReturnLocation.dataLabel32AtOffset(stubInfo.patch.deltaCallToLoadOrStore), 0);
-#else
-    repatchBuffer.repatch(stubInfo.callReturnLocation.dataLabel32AtOffset(stubInfo.patch.deltaCallToTagLoadOrStore), 0);
-    repatchBuffer.repatch(stubInfo.callReturnLocation.dataLabel32AtOffset(stubInfo.patch.deltaCallToPayloadLoadOrStore), 0);
-#endif
-    repatchBuffer.relink(stubInfo.callReturnLocation.jumpAtOffset(stubInfo.patch.deltaCallToJump), stubInfo.callReturnLocation.labelAtOffset(stubInfo.patch.deltaCallToSlowCase));
+
+    ftlThunkAwareRepatchCall(codeBlock, stubInfo.slowPathCallLocation(), optimizedFunction);
+    InlineAccess::rewireStubAsJump(*codeBlock->vm(), stubInfo, stubInfo.slowPathStartLocation());
 }
 
-void resetIn(RepatchBuffer& repatchBuffer, StructureStubInfo& stubInfo)
+void resetIn(CodeBlock*, StructureStubInfo& stubInfo)
 {
-    repatchBuffer.relink(stubInfo.callReturnLocation.jumpAtOffset(stubInfo.patch.deltaCallToJump), stubInfo.callReturnLocation.labelAtOffset(stubInfo.patch.deltaCallToSlowCase));
+    MacroAssembler::repatchJump(stubInfo.patchableJumpForIn(), stubInfo.slowPathStartLocation());
 }
 
 } // namespace JSC