Imported QtWebKit TP3 (git b57bc6801f1876c3220d5a4bfea33d620d477443)

Change-Id: I3b1d8a2808782c9f34d50240000e20cb38d3680f
Reviewed-by: Konstantin Tokarev <annulen@yandex.ru>

1 files changed, 330 insertions, 132 deletions

diff --git a/Source/JavaScriptCore/bytecode/PutByIdStatus.cpp b/Source/JavaScriptCore/bytecode/PutByIdStatus.cpp
index 24a57eb50..3d066b9ae 100644
--- a/Source/JavaScriptCore/bytecode/PutByIdStatus.cpp
+++ b/Source/JavaScriptCore/bytecode/PutByIdStatus.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2012 Apple Inc. All rights reserved.
+ * Copyright (C) 2012-2015 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -27,193 +27,391 @@
 #include "PutByIdStatus.h"
 
 #include "CodeBlock.h"
+#include "ComplexGetStatus.h"
 #include "LLIntData.h"
 #include "LowLevelInterpreter.h"
-#include "Operations.h"
+#include "JSCInlines.h"
+#include "PolymorphicAccess.h"
 #include "Structure.h"
 #include "StructureChain.h"
+#include <wtf/ListDump.h>
 
 namespace JSC {
 
-PutByIdStatus PutByIdStatus::computeFromLLInt(CodeBlock* profiledBlock, unsigned bytecodeIndex, Identifier& ident)
+bool PutByIdStatus::appendVariant(const PutByIdVariant& variant)
+{
+    for (unsigned i = 0; i < m_variants.size(); ++i) {
+        if (m_variants[i].attemptToMerge(variant))
+            return true;
+    }
+    for (unsigned i = 0; i < m_variants.size(); ++i) {
+        if (m_variants[i].oldStructure().overlaps(variant.oldStructure()))
+            return false;
+    }
+    m_variants.append(variant);
+    return true;
+}
+
+#if ENABLE(DFG_JIT)
+bool PutByIdStatus::hasExitSite(const ConcurrentJITLocker& locker, CodeBlock* profiledBlock, unsigned bytecodeIndex)
+{
+    return profiledBlock->hasExitSite(locker, DFG::FrequentExitSite(bytecodeIndex, BadCache))
+        || profiledBlock->hasExitSite(locker, DFG::FrequentExitSite(bytecodeIndex, BadConstantCache));
+    
+}
+#endif
+
+PutByIdStatus PutByIdStatus::computeFromLLInt(CodeBlock* profiledBlock, unsigned bytecodeIndex, UniquedStringImpl* uid)
 {
     UNUSED_PARAM(profiledBlock);
     UNUSED_PARAM(bytecodeIndex);
-    UNUSED_PARAM(ident);
-#if ENABLE(LLINT)
+    UNUSED_PARAM(uid);
+
+    VM& vm = *profiledBlock->vm();
+    
     Instruction* instruction = profiledBlock->instructions().begin() + bytecodeIndex;
 
-    Structure* structure = instruction[4].u.structure.get();
-    if (!structure)
-        return PutByIdStatus(NoInformation, 0, 0, 0, invalidOffset);
+    StructureID structureID = instruction[4].u.structureID;
+    if (!structureID)
+        return PutByIdStatus(NoInformation);
     
-    if (instruction[0].u.opcode == LLInt::getOpcode(llint_op_put_by_id)
-        || instruction[0].u.opcode == LLInt::getOpcode(llint_op_put_by_id_out_of_line)) {
-        PropertyOffset offset = structure->get(*profiledBlock->vm(), ident);
+    Structure* structure = vm.heap.structureIDTable().get(structureID);
+
+    StructureID newStructureID = instruction[6].u.structureID;
+    if (!newStructureID) {
+        PropertyOffset offset = structure->getConcurrently(uid);
         if (!isValidOffset(offset))
-            return PutByIdStatus(NoInformation, 0, 0, 0, invalidOffset);
+            return PutByIdStatus(NoInformation);
         
-        return PutByIdStatus(SimpleReplace, structure, 0, 0, offset);
+        return PutByIdVariant::replace(structure, offset, structure->inferredTypeDescriptorFor(uid));
     }
+
+    Structure* newStructure = vm.heap.structureIDTable().get(newStructureID);
     
     ASSERT(structure->transitionWatchpointSetHasBeenInvalidated());
     
-    ASSERT(instruction[0].u.opcode == LLInt::getOpcode(llint_op_put_by_id_transition_direct)
-           || instruction[0].u.opcode == LLInt::getOpcode(llint_op_put_by_id_transition_normal)
-           || instruction[0].u.opcode == LLInt::getOpcode(llint_op_put_by_id_transition_direct_out_of_line)
-           || instruction[0].u.opcode == LLInt::getOpcode(llint_op_put_by_id_transition_normal_out_of_line));
-    
-    Structure* newStructure = instruction[6].u.structure.get();
-    StructureChain* chain = instruction[7].u.structureChain.get();
-    ASSERT(newStructure);
-    ASSERT(chain);
-    
-    PropertyOffset offset = newStructure->get(*profiledBlock->vm(), ident);
+    PropertyOffset offset = newStructure->getConcurrently(uid);
     if (!isValidOffset(offset))
-        return PutByIdStatus(NoInformation, 0, 0, 0, invalidOffset);
+        return PutByIdStatus(NoInformation);
     
-    return PutByIdStatus(SimpleTransition, structure, newStructure, chain, offset);
-#else
-    return PutByIdStatus(NoInformation, 0, 0, 0, invalidOffset);
-#endif
+    ObjectPropertyConditionSet conditionSet;
+    if (!(instruction[8].u.putByIdFlags & PutByIdIsDirect)) {
+        conditionSet =
+            generateConditionsForPropertySetterMissConcurrently(
+                *profiledBlock->vm(), profiledBlock->globalObject(), structure, uid);
+        if (!conditionSet.isValid())
+            return PutByIdStatus(NoInformation);
+    }
+    
+    return PutByIdVariant::transition(
+        structure, newStructure, conditionSet, offset, newStructure->inferredTypeDescriptorFor(uid));
 }
 
-PutByIdStatus PutByIdStatus::computeFor(CodeBlock* profiledBlock, unsigned bytecodeIndex, Identifier& ident)
+PutByIdStatus PutByIdStatus::computeFor(CodeBlock* profiledBlock, StubInfoMap& map, unsigned bytecodeIndex, UniquedStringImpl* uid)
 {
+    ConcurrentJITLocker locker(profiledBlock->m_lock);
+    
     UNUSED_PARAM(profiledBlock);
     UNUSED_PARAM(bytecodeIndex);
-    UNUSED_PARAM(ident);
-#if ENABLE(JIT) && ENABLE(VALUE_PROFILER)
-    if (!profiledBlock->numberOfStructureStubInfos())
-        return computeFromLLInt(profiledBlock, bytecodeIndex, ident);
-    
-    if (profiledBlock->likelyToTakeSlowCase(bytecodeIndex))
-        return PutByIdStatus(TakesSlowPath, 0, 0, 0, invalidOffset);
+    UNUSED_PARAM(uid);
+#if ENABLE(DFG_JIT)
+    if (hasExitSite(locker, profiledBlock, bytecodeIndex))
+        return PutByIdStatus(TakesSlowPath);
     
-    StructureStubInfo& stubInfo = profiledBlock->getStubInfo(bytecodeIndex);
-    if (!stubInfo.seen)
-        return computeFromLLInt(profiledBlock, bytecodeIndex, ident);
+    StructureStubInfo* stubInfo = map.get(CodeOrigin(bytecodeIndex));
+    PutByIdStatus result = computeForStubInfo(
+        locker, profiledBlock, stubInfo, uid,
+        CallLinkStatus::computeExitSiteData(locker, profiledBlock, bytecodeIndex));
+    if (!result)
+        return computeFromLLInt(profiledBlock, bytecodeIndex, uid);
     
-    if (stubInfo.resetByGC)
-        return PutByIdStatus(TakesSlowPath, 0, 0, 0, invalidOffset);
+    return result;
+#else // ENABLE(JIT)
+    UNUSED_PARAM(map);
+    return PutByIdStatus(NoInformation);
+#endif // ENABLE(JIT)
+}
 
-    switch (stubInfo.accessType) {
-    case access_unset:
-        // If the JIT saw it but didn't optimize it, then assume that this takes slow path.
-        return PutByIdStatus(TakesSlowPath, 0, 0, 0, invalidOffset);
+#if ENABLE(JIT)
+PutByIdStatus PutByIdStatus::computeForStubInfo(const ConcurrentJITLocker& locker, CodeBlock* baselineBlock, StructureStubInfo* stubInfo, CodeOrigin codeOrigin, UniquedStringImpl* uid)
+{
+    return computeForStubInfo(
+        locker, baselineBlock, stubInfo, uid,
+        CallLinkStatus::computeExitSiteData(locker, baselineBlock, codeOrigin.bytecodeIndex));
+}
+
+PutByIdStatus PutByIdStatus::computeForStubInfo(
+    const ConcurrentJITLocker& locker, CodeBlock* profiledBlock, StructureStubInfo* stubInfo,
+    UniquedStringImpl* uid, CallLinkStatus::ExitSiteData callExitSiteData)
+{
+    if (!stubInfo || !stubInfo->everConsidered)
+        return PutByIdStatus();
+    
+    if (stubInfo->tookSlowPath)
+        return PutByIdStatus(TakesSlowPath);
+    
+    switch (stubInfo->cacheType) {
+    case CacheType::Unset:
+        // This means that we attempted to cache but failed for some reason.
+        return PutByIdStatus(TakesSlowPath);
         
-    case access_put_by_id_replace: {
-        PropertyOffset offset = stubInfo.u.putByIdReplace.baseObjectStructure->get(
-            *profiledBlock->vm(), ident);
+    case CacheType::PutByIdReplace: {
+        PropertyOffset offset =
+            stubInfo->u.byIdSelf.baseObjectStructure->getConcurrently(uid);
         if (isValidOffset(offset)) {
-            return PutByIdStatus(
-                SimpleReplace,
-                stubInfo.u.putByIdReplace.baseObjectStructure.get(),
-                0, 0,
-                offset);
+            return PutByIdVariant::replace(
+                stubInfo->u.byIdSelf.baseObjectStructure.get(), offset, InferredType::Top);
         }
-        return PutByIdStatus(TakesSlowPath, 0, 0, 0, invalidOffset);
+        return PutByIdStatus(TakesSlowPath);
     }
         
-    case access_put_by_id_transition_normal:
-    case access_put_by_id_transition_direct: {
-        ASSERT(stubInfo.u.putByIdTransition.previousStructure->transitionWatchpointSetHasBeenInvalidated());
-        PropertyOffset offset = stubInfo.u.putByIdTransition.structure->get(
-            *profiledBlock->vm(), ident);
-        if (isValidOffset(offset)) {
-            return PutByIdStatus(
-                SimpleTransition,
-                stubInfo.u.putByIdTransition.previousStructure.get(),
-                stubInfo.u.putByIdTransition.structure.get(),
-                stubInfo.u.putByIdTransition.chain.get(),
-                offset);
+    case CacheType::Stub: {
+        PolymorphicAccess* list = stubInfo->u.stub;
+        
+        PutByIdStatus result;
+        result.m_state = Simple;
+        
+        State slowPathState = TakesSlowPath;
+        for (unsigned i = 0; i < list->size(); ++i) {
+            const AccessCase& access = list->at(i);
+            if (access.doesCalls())
+                slowPathState = MakesCalls;
         }
-        return PutByIdStatus(TakesSlowPath, 0, 0, 0, invalidOffset);
+        
+        for (unsigned i = 0; i < list->size(); ++i) {
+            const AccessCase& access = list->at(i);
+            if (access.viaProxy())
+                return PutByIdStatus(slowPathState);
+            
+            PutByIdVariant variant;
+            
+            switch (access.type()) {
+            case AccessCase::Replace: {
+                Structure* structure = access.structure();
+                PropertyOffset offset = structure->getConcurrently(uid);
+                if (!isValidOffset(offset))
+                    return PutByIdStatus(slowPathState);
+                variant = PutByIdVariant::replace(
+                    structure, offset, structure->inferredTypeDescriptorFor(uid));
+                break;
+            }
+                
+            case AccessCase::Transition: {
+                PropertyOffset offset =
+                    access.newStructure()->getConcurrently(uid);
+                if (!isValidOffset(offset))
+                    return PutByIdStatus(slowPathState);
+                ObjectPropertyConditionSet conditionSet = access.conditionSet();
+                if (!conditionSet.structuresEnsureValidity())
+                    return PutByIdStatus(slowPathState);
+                variant = PutByIdVariant::transition(
+                    access.structure(), access.newStructure(), conditionSet, offset,
+                    access.newStructure()->inferredTypeDescriptorFor(uid));
+                break;
+            }
+                
+            case AccessCase::Setter: {
+                Structure* structure = access.structure();
+                
+                ComplexGetStatus complexGetStatus = ComplexGetStatus::computeFor(
+                    structure, access.conditionSet(), uid);
+                
+                switch (complexGetStatus.kind()) {
+                case ComplexGetStatus::ShouldSkip:
+                    continue;
+                    
+                case ComplexGetStatus::TakesSlowPath:
+                    return PutByIdStatus(slowPathState);
+                    
+                case ComplexGetStatus::Inlineable: {
+                    CallLinkInfo* callLinkInfo = access.callLinkInfo();
+                    ASSERT(callLinkInfo);
+                    std::unique_ptr<CallLinkStatus> callLinkStatus =
+                        std::make_unique<CallLinkStatus>(
+                            CallLinkStatus::computeFor(
+                                locker, profiledBlock, *callLinkInfo, callExitSiteData));
+                    
+                    variant = PutByIdVariant::setter(
+                        structure, complexGetStatus.offset(), complexGetStatus.conditionSet(),
+                        WTFMove(callLinkStatus));
+                } }
+                break;
+            }
+                
+            case AccessCase::CustomValueSetter:
+            case AccessCase::CustomAccessorSetter:
+                return PutByIdStatus(MakesCalls);
+
+            default:
+                return PutByIdStatus(slowPathState);
+            }
+            
+            if (!result.appendVariant(variant))
+                return PutByIdStatus(slowPathState);
+        }
+        
+        return result;
     }
         
     default:
-        return PutByIdStatus(TakesSlowPath, 0, 0, 0, invalidOffset);
+        return PutByIdStatus(TakesSlowPath);
     }
-#else // ENABLE(JIT)
-    return PutByIdStatus(NoInformation, 0, 0, 0, invalidOffset);
-#endif // ENABLE(JIT)
 }
+#endif
 
-PutByIdStatus PutByIdStatus::computeFor(VM& vm, JSGlobalObject* globalObject, Structure* structure, Identifier& ident, bool isDirect)
+PutByIdStatus PutByIdStatus::computeFor(CodeBlock* baselineBlock, CodeBlock* dfgBlock, StubInfoMap& baselineMap, StubInfoMap& dfgMap, CodeOrigin codeOrigin, UniquedStringImpl* uid)
 {
-    if (PropertyName(ident).asIndex() != PropertyName::NotAnIndex)
-        return PutByIdStatus(TakesSlowPath);
-    
-    if (structure->typeInfo().overridesGetOwnPropertySlot())
-        return PutByIdStatus(TakesSlowPath);
+#if ENABLE(DFG_JIT)
+    if (dfgBlock) {
+        CallLinkStatus::ExitSiteData exitSiteData;
+        {
+            ConcurrentJITLocker locker(baselineBlock->m_lock);
+            if (hasExitSite(locker, baselineBlock, codeOrigin.bytecodeIndex))
+                return PutByIdStatus(TakesSlowPath);
+            exitSiteData = CallLinkStatus::computeExitSiteData(
+                locker, baselineBlock, codeOrigin.bytecodeIndex);
+        }
+            
+        PutByIdStatus result;
+        {
+            ConcurrentJITLocker locker(dfgBlock->m_lock);
+            result = computeForStubInfo(
+                locker, dfgBlock, dfgMap.get(codeOrigin), uid, exitSiteData);
+        }
+        
+        // We use TakesSlowPath in some cases where the stub was unset. That's weird and
+        // it would be better not to do that. But it means that we have to defend
+        // ourselves here.
+        if (result.isSimple())
+            return result;
+    }
+#else
+    UNUSED_PARAM(dfgBlock);
+    UNUSED_PARAM(dfgMap);
+#endif
 
-    if (!structure->propertyAccessesAreCacheable())
+    return computeFor(baselineBlock, baselineMap, codeOrigin.bytecodeIndex, uid);
+}
+
+PutByIdStatus PutByIdStatus::computeFor(JSGlobalObject* globalObject, const StructureSet& set, UniquedStringImpl* uid, bool isDirect)
+{
+    if (parseIndex(*uid))
         return PutByIdStatus(TakesSlowPath);
+
+    if (set.isEmpty())
+        return PutByIdStatus();
     
-    unsigned attributes;
-    JSCell* specificValue;
-    PropertyOffset offset = structure->get(vm, ident, attributes, specificValue);
-    if (isValidOffset(offset)) {
-        if (attributes & (Accessor | ReadOnly))
+    PutByIdStatus result;
+    result.m_state = Simple;
+    for (unsigned i = 0; i < set.size(); ++i) {
+        Structure* structure = set[i];
+        
+        if (structure->typeInfo().overridesGetOwnPropertySlot() && structure->typeInfo().type() != GlobalObjectType)
             return PutByIdStatus(TakesSlowPath);
-        if (specificValue) {
-            // We need the PutById slow path to verify that we're storing the right value into
-            // the specialized slot.
+
+        if (!structure->propertyAccessesAreCacheable())
             return PutByIdStatus(TakesSlowPath);
+    
+        unsigned attributes;
+        PropertyOffset offset = structure->getConcurrently(uid, attributes);
+        if (isValidOffset(offset)) {
+            if (attributes & CustomAccessor)
+                return PutByIdStatus(MakesCalls);
+
+            if (attributes & (Accessor | ReadOnly))
+                return PutByIdStatus(TakesSlowPath);
+            
+            WatchpointSet* replaceSet = structure->propertyReplacementWatchpointSet(offset);
+            if (!replaceSet || replaceSet->isStillValid()) {
+                // When this executes, it'll create, and fire, this replacement watchpoint set.
+                // That means that  this has probably never executed or that something fishy is
+                // going on. Also, we cannot create or fire the watchpoint set from the concurrent
+                // JIT thread, so even if we wanted to do this, we'd need to have a lazy thingy.
+                // So, better leave this alone and take slow path.
+                return PutByIdStatus(TakesSlowPath);
+            }
+
+            PutByIdVariant variant =
+                PutByIdVariant::replace(structure, offset, structure->inferredTypeDescriptorFor(uid));
+            if (!result.appendVariant(variant))
+                return PutByIdStatus(TakesSlowPath);
+            continue;
         }
-        return PutByIdStatus(SimpleReplace, structure, 0, 0, offset);
-    }
     
-    // Our hypothesis is that we're doing a transition. Before we prove that this is really
-    // true, we want to do some sanity checks.
+        // Our hypothesis is that we're doing a transition. Before we prove that this is really
+        // true, we want to do some sanity checks.
     
-    // Don't cache put transitions on dictionaries.
-    if (structure->isDictionary())
-        return PutByIdStatus(TakesSlowPath);
+        // Don't cache put transitions on dictionaries.
+        if (structure->isDictionary())
+            return PutByIdStatus(TakesSlowPath);
 
-    // If the structure corresponds to something that isn't an object, then give up, since
-    // we don't want to be adding properties to strings.
-    if (structure->typeInfo().type() == StringType)
-        return PutByIdStatus(TakesSlowPath);
+        // If the structure corresponds to something that isn't an object, then give up, since
+        // we don't want to be adding properties to strings.
+        if (!structure->typeInfo().isObject())
+            return PutByIdStatus(TakesSlowPath);
+    
+        ObjectPropertyConditionSet conditionSet;
+        if (!isDirect) {
+            conditionSet = generateConditionsForPropertySetterMissConcurrently(
+                globalObject->vm(), globalObject, structure, uid);
+            if (!conditionSet.isValid())
+                return PutByIdStatus(TakesSlowPath);
+        }
     
-    if (!isDirect) {
-        // If the prototype chain has setters or read-only properties, then give up.
-        if (structure->prototypeChainMayInterceptStoreTo(vm, ident))
+        // We only optimize if there is already a structure that the transition is cached to.
+        Structure* transition =
+            Structure::addPropertyTransitionToExistingStructureConcurrently(structure, uid, 0, offset);
+        if (!transition)
             return PutByIdStatus(TakesSlowPath);
-        
-        // If the prototype chain hasn't been normalized (i.e. there are proxies or dictionaries)
-        // then give up. The dictionary case would only happen if this structure has not been
-        // used in an optimized put_by_id transition. And really the only reason why we would
-        // bail here is that I don't really feel like having the optimizing JIT go and flatten
-        // dictionaries if we have evidence to suggest that those objects were never used as
-        // prototypes in a cacheable prototype access - i.e. there's a good chance that some of
-        // the other checks below will fail.
-        if (!isPrototypeChainNormalized(globalObject, structure))
+        ASSERT(isValidOffset(offset));
+    
+        bool didAppend = result.appendVariant(
+            PutByIdVariant::transition(
+                structure, transition, conditionSet, offset,
+                transition->inferredTypeDescriptorFor(uid)));
+        if (!didAppend)
             return PutByIdStatus(TakesSlowPath);
     }
     
-    // We only optimize if there is already a structure that the transition is cached to.
-    // Among other things, this allows us to guard against a transition with a specific
-    // value.
-    //
-    // - If we're storing a value that could be specific: this would only be a problem if
-    //   the existing transition did have a specific value already, since if it didn't,
-    //   then we would behave "as if" we were not storing a specific value. If it did
-    //   have a specific value, then we'll know - the fact that we pass 0 for
-    //   specificValue will tell us.
-    //
-    // - If we're not storing a value that could be specific: again, this would only be a
-    //   problem if the existing transition did have a specific value, which we check for
-    //   by passing 0 for the specificValue.
-    Structure* transition = Structure::addPropertyTransitionToExistingStructure(structure, ident, 0, 0, offset);
-    if (!transition)
-        return PutByIdStatus(TakesSlowPath); // This occurs in bizarre cases only. See above.
-    ASSERT(!transition->transitionDidInvolveSpecificValue());
-    ASSERT(isValidOffset(offset));
-    
-    return PutByIdStatus(
-        SimpleTransition, structure, transition,
-        structure->prototypeChain(vm, globalObject), offset);
+    return result;
+}
+
+bool PutByIdStatus::makesCalls() const
+{
+    if (m_state == MakesCalls)
+        return true;
+    
+    if (m_state != Simple)
+        return false;
+    
+    for (unsigned i = m_variants.size(); i--;) {
+        if (m_variants[i].makesCalls())
+            return true;
+    }
+    
+    return false;
+}
+
+void PutByIdStatus::dump(PrintStream& out) const
+{
+    switch (m_state) {
+    case NoInformation:
+        out.print("(NoInformation)");
+        return;
+        
+    case Simple:
+        out.print("(", listDump(m_variants), ")");
+        return;
+        
+    case TakesSlowPath:
+        out.print("(TakesSlowPath)");
+        return;
+    case MakesCalls:
+        out.print("(MakesCalls)");
+        return;
+    }
+    
+    RELEASE_ASSERT_NOT_REACHED();
 }
 
 } // namespace JSC