webkitgtk-2.12.3webkitgtk-2.12.3

1 files changed, 996 insertions, 212 deletions

diff --git a/Source/JavaScriptCore/dfg/DFGGraph.cpp b/Source/JavaScriptCore/dfg/DFGGraph.cpp
index 8256007e9..541c84ebb 100644
--- a/Source/JavaScriptCore/dfg/DFGGraph.cpp
+++ b/Source/JavaScriptCore/dfg/DFGGraph.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2011, 2013 Apple Inc. All rights reserved.
+ * Copyright (C) 2011, 2013-2015 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -26,23 +26,33 @@
 #include "config.h"
 #include "DFGGraph.h"
 
+#if ENABLE(DFG_JIT)
+
+#include "BytecodeKills.h"
 #include "BytecodeLivenessAnalysisInlines.h"
 #include "CodeBlock.h"
 #include "CodeBlockWithJITType.h"
+#include "DFGBlockWorklist.h"
 #include "DFGClobberSet.h"
+#include "DFGClobbersExitState.h"
+#include "DFGCFG.h"
+#include "DFGDominators.h"
 #include "DFGJITCode.h"
+#include "DFGMayExit.h"
+#include "DFGNaturalLoops.h"
+#include "DFGPrePostNumbering.h"
 #include "DFGVariableAccessDataDump.h"
 #include "FullBytecodeLiveness.h"
 #include "FunctionExecutableDump.h"
 #include "JIT.h"
-#include "JSActivation.h"
+#include "JSLexicalEnvironment.h"
+#include "MaxFrameExtentForSlowPathCall.h"
 #include "OperandsInlines.h"
-#include "Operations.h"
+#include "JSCInlines.h"
+#include "StackAlignment.h"
 #include <wtf/CommaPrinter.h>
 #include <wtf/ListDump.h>
 
-#if ENABLE(DFG_JIT)
-
 namespace JSC { namespace DFG {
 
 // Creates an array of stringized names.
@@ -55,27 +65,35 @@ static const char* dfgOpNames[] = {
 Graph::Graph(VM& vm, Plan& plan, LongLivedState& longLivedState)
     : m_vm(vm)
     , m_plan(plan)
-    , m_codeBlock(m_plan.codeBlock.get())
+    , m_codeBlock(m_plan.codeBlock)
     , m_profiledBlock(m_codeBlock->alternative())
     , m_allocator(longLivedState.m_allocator)
-    , m_mustHandleAbstractValues(OperandsLike, plan.mustHandleValues)
-    , m_inlineCallFrames(adoptPtr(new InlineCallFrameSet()))
-    , m_hasArguments(false)
+    , m_cfg(std::make_unique<CFG>(*this))
     , m_nextMachineLocal(0)
-    , m_machineCaptureStart(std::numeric_limits<int>::max())
     , m_fixpointState(BeforeFixpoint)
+    , m_structureRegistrationState(HaveNotStartedRegistering)
     , m_form(LoadStore)
     , m_unificationState(LocallyUnified)
     , m_refCountState(EverythingIsLive)
 {
     ASSERT(m_profiledBlock);
     
-    for (unsigned i = m_mustHandleAbstractValues.size(); i--;)
-        m_mustHandleAbstractValues[i].setMostSpecific(*this, plan.mustHandleValues[i]);
+    m_hasDebuggerEnabled = m_profiledBlock->globalObject()->hasDebugger()
+        || Options::forceDebuggerBytecodeGeneration();
 }
 
 Graph::~Graph()
 {
+    for (BlockIndex blockIndex = numBlocks(); blockIndex--;) {
+        BasicBlock* block = this->block(blockIndex);
+        if (!block)
+            continue;
+
+        for (unsigned phiIndex = block->phis.size(); phiIndex--;)
+            m_allocator.free(block->phis[phiIndex]);
+        for (unsigned nodeIndex = block->size(); nodeIndex--;)
+            m_allocator.free(block->at(nodeIndex));
+    }
     m_allocator.freeAll();
 }
 
@@ -90,16 +108,22 @@ static void printWhiteSpace(PrintStream& out, unsigned amount)
         out.print(" ");
 }
 
-bool Graph::dumpCodeOrigin(PrintStream& out, const char* prefix, Node* previousNode, Node* currentNode, DumpContext* context)
+bool Graph::dumpCodeOrigin(PrintStream& out, const char* prefix, Node*& previousNodeRef, Node* currentNode, DumpContext* context)
 {
+    if (!currentNode->origin.semantic)
+        return false;
+    
+    Node* previousNode = previousNodeRef;
+    previousNodeRef = currentNode;
+
     if (!previousNode)
         return false;
     
-    if (previousNode->codeOrigin.inlineCallFrame == currentNode->codeOrigin.inlineCallFrame)
+    if (previousNode->origin.semantic.inlineCallFrame == currentNode->origin.semantic.inlineCallFrame)
         return false;
     
-    Vector<CodeOrigin> previousInlineStack = previousNode->codeOrigin.inlineStack();
-    Vector<CodeOrigin> currentInlineStack = currentNode->codeOrigin.inlineStack();
+    Vector<CodeOrigin> previousInlineStack = previousNode->origin.semantic.inlineStack();
+    Vector<CodeOrigin> currentInlineStack = currentNode->origin.semantic.inlineStack();
     unsigned commonSize = std::min(previousInlineStack.size(), currentInlineStack.size());
     unsigned indexOfDivergence = commonSize;
     for (unsigned i = 0; i < commonSize; ++i) {
@@ -132,7 +156,7 @@ bool Graph::dumpCodeOrigin(PrintStream& out, const char* prefix, Node* previousN
 
 int Graph::amountOfNodeWhiteSpace(Node* node)
 {
-    return (node->codeOrigin.inlineDepth() - 1) * 2;
+    return (node->origin.semantic.inlineDepth() - 1) * 2;
 }
 
 void Graph::printNodeWhiteSpace(PrintStream& out, Node* node)
@@ -145,7 +169,6 @@ void Graph::dump(PrintStream& out, const char* prefix, Node* node, DumpContext*
     NodeType op = node->op();
 
     unsigned refCount = node->refCount();
-    bool skipped = !refCount;
     bool mustGenerate = node->mustGenerate();
     if (mustGenerate)
         --refCount;
@@ -167,11 +190,10 @@ void Graph::dump(PrintStream& out, const char* prefix, Node* node, DumpContext*
     // (5) The arguments to the operation. The may be of the form:
     //         @#   - a NodeIndex referencing a prior node in the graph.
     //         arg# - an argument number.
-    //         $#   - the index in the CodeBlock of a constant { for numeric constants the value is displayed | for integers, in both decimal and hex }.
     //         id#  - the index in the CodeBlock of an identifier { if codeBlock is passed to dump(), the string representation is displayed }.
-    //         var# - the index of a var on the global object, used by GetGlobalVar/PutGlobalVar operations.
-    out.printf("% 4d:%s<%c%u:", (int)node->index(), skipped ? "  skipped  " : "           ", mustGenerate ? '!' : ' ', refCount);
-    if (node->hasResult() && !skipped && node->hasVirtualRegister())
+    //         var# - the index of a var on the global object, used by GetGlobalVar/GetGlobalLexicalVariable/PutGlobalVariable operations.
+    out.printf("% 4d:<%c%u:", (int)node->index(), mustGenerate ? '!' : ' ', refCount);
+    if (node->hasResult() && node->hasVirtualRegister() && node->virtualRegister().isValid())
         out.print(node->virtualRegister());
     else
         out.print("-");
@@ -200,88 +222,97 @@ void Graph::dump(PrintStream& out, const char* prefix, Node* node, DumpContext*
         out.print(comma, node->arrayMode());
     if (node->hasArithMode())
         out.print(comma, node->arithMode());
-    if (node->hasVarNumber())
-        out.print(comma, node->varNumber());
+    if (node->hasArithRoundingMode())
+        out.print(comma, "Rounding:", node->arithRoundingMode());
+    if (node->hasScopeOffset())
+        out.print(comma, node->scopeOffset());
+    if (node->hasDirectArgumentsOffset())
+        out.print(comma, node->capturedArgumentsOffset());
     if (node->hasRegisterPointer())
-        out.print(comma, "global", globalObjectFor(node->codeOrigin)->findRegisterIndex(node->registerPointer()), "(", RawPointer(node->registerPointer()), ")");
+        out.print(comma, "global", "(", RawPointer(node->variablePointer()), ")");
     if (node->hasIdentifier())
         out.print(comma, "id", node->identifierNumber(), "{", identifiers()[node->identifierNumber()], "}");
+    if (node->hasPromotedLocationDescriptor())
+        out.print(comma, node->promotedLocationDescriptor());
     if (node->hasStructureSet())
         out.print(comma, inContext(node->structureSet(), context));
     if (node->hasStructure())
         out.print(comma, inContext(*node->structure(), context));
-    if (node->hasStructureTransitionData())
-        out.print(comma, inContext(*node->structureTransitionData().previousStructure, context), " -> ", inContext(*node->structureTransitionData().newStructure, context));
-    if (node->hasFunction()) {
-        out.print(comma, "function(", RawPointer(node->function()), ", ");
-        if (node->function()->inherits(JSFunction::info())) {
-            JSFunction* function = jsCast<JSFunction*>(node->function());
-            if (function->isHostFunction())
-                out.print("<host function>");
-            else
-                out.print(FunctionExecutableDump(function->jsExecutable()));
-        } else
-            out.print("<not JSFunction>");
-        out.print(")");
-    }
-    if (node->hasExecutable()) {
-        if (node->executable()->inherits(FunctionExecutable::info()))
-            out.print(comma, "executable(", FunctionExecutableDump(jsCast<FunctionExecutable*>(node->executable())), ")");
-        else
-            out.print(comma, "executable(not function: ", RawPointer(node->executable()), ")");
-    }
-    if (node->hasFunctionDeclIndex()) {
-        FunctionExecutable* executable = m_codeBlock->functionDecl(node->functionDeclIndex());
-        out.print(comma, FunctionExecutableDump(executable));
+    if (node->hasTransition()) {
+        out.print(comma, pointerDumpInContext(node->transition(), context));
+#if USE(JSVALUE64)
+        out.print(", ID:", node->transition()->next->id());
+#else
+        out.print(", ID:", RawPointer(node->transition()->next));
+#endif
     }
-    if (node->hasFunctionExprIndex()) {
-        FunctionExecutable* executable = m_codeBlock->functionExpr(node->functionExprIndex());
-        out.print(comma, FunctionExecutableDump(executable));
+    if (node->hasCellOperand()) {
+        if (!node->cellOperand()->value() || !node->cellOperand()->value().isCell())
+            out.print(comma, "invalid cell operand: ", node->cellOperand()->value());
+        else {
+            out.print(comma, pointerDump(node->cellOperand()->value().asCell()));
+            if (node->cellOperand()->value().isCell()) {
+                CallVariant variant(node->cellOperand()->value().asCell());
+                if (ExecutableBase* executable = variant.executable()) {
+                    if (executable->isHostFunction())
+                        out.print(comma, "<host function>");
+                    else if (FunctionExecutable* functionExecutable = jsDynamicCast<FunctionExecutable*>(executable))
+                        out.print(comma, FunctionExecutableDump(functionExecutable));
+                    else
+                        out.print(comma, "<non-function executable>");
+                }
+            }
+        }
     }
     if (node->hasStorageAccessData()) {
-        StorageAccessData& storageAccessData = m_storageAccessData[node->storageAccessDataIndex()];
+        StorageAccessData& storageAccessData = node->storageAccessData();
         out.print(comma, "id", storageAccessData.identifierNumber, "{", identifiers()[storageAccessData.identifierNumber], "}");
         out.print(", ", static_cast<ptrdiff_t>(storageAccessData.offset));
+        out.print(", inferredType = ", inContext(storageAccessData.inferredType, context));
+    }
+    if (node->hasMultiGetByOffsetData()) {
+        MultiGetByOffsetData& data = node->multiGetByOffsetData();
+        out.print(comma, "id", data.identifierNumber, "{", identifiers()[data.identifierNumber], "}");
+        for (unsigned i = 0; i < data.cases.size(); ++i)
+            out.print(comma, inContext(data.cases[i], context));
+    }
+    if (node->hasMultiPutByOffsetData()) {
+        MultiPutByOffsetData& data = node->multiPutByOffsetData();
+        out.print(comma, "id", data.identifierNumber, "{", identifiers()[data.identifierNumber], "}");
+        for (unsigned i = 0; i < data.variants.size(); ++i)
+            out.print(comma, inContext(data.variants[i], context));
     }
     ASSERT(node->hasVariableAccessData(*this) == node->hasLocal(*this));
     if (node->hasVariableAccessData(*this)) {
-        VariableAccessData* variableAccessData = node->variableAccessData();
-        VirtualRegister operand = variableAccessData->local();
-        if (operand.isArgument())
-            out.print(comma, "arg", operand.toArgument(), "(", VariableAccessDataDump(*this, variableAccessData), ")");
-        else
-            out.print(comma, "loc", operand.toLocal(), "(", VariableAccessDataDump(*this, variableAccessData), ")");
-        
-        operand = variableAccessData->machineLocal();
-        if (operand.isValid()) {
-            if (operand.isArgument())
-                out.print(comma, "machine:arg", operand.toArgument());
-            else
-                out.print(comma, "machine:loc", operand.toLocal());
+        VariableAccessData* variableAccessData = node->tryGetVariableAccessData();
+        if (variableAccessData) {
+            VirtualRegister operand = variableAccessData->local();
+            out.print(comma, variableAccessData->local(), "(", VariableAccessDataDump(*this, variableAccessData), ")");
+            operand = variableAccessData->machineLocal();
+            if (operand.isValid())
+                out.print(comma, "machine:", operand);
         }
     }
-    if (node->hasUnlinkedLocal()) {
-        VirtualRegister operand = node->unlinkedLocal();
-        if (operand.isArgument())
-            out.print(comma, "arg", operand.toArgument());
-        else
-            out.print(comma, "loc", operand.toLocal());
+    if (node->hasStackAccessData()) {
+        StackAccessData* data = node->stackAccessData();
+        out.print(comma, data->local);
+        if (data->machineLocal.isValid())
+            out.print(comma, "machine:", data->machineLocal);
+        out.print(comma, data->format);
     }
+    if (node->hasUnlinkedLocal()) 
+        out.print(comma, node->unlinkedLocal());
     if (node->hasUnlinkedMachineLocal()) {
         VirtualRegister operand = node->unlinkedMachineLocal();
-        if (operand.isValid()) {
-            if (operand.isArgument())
-                out.print(comma, "machine:arg", operand.toArgument());
-            else
-                out.print(comma, "machine:loc", operand.toLocal());
-        }
+        if (operand.isValid())
+            out.print(comma, "machine:", operand);
     }
     if (node->hasConstantBuffer()) {
         out.print(comma);
         out.print(node->startConstant(), ":[");
         CommaPrinter anotherComma;
         for (unsigned i = 0; i < node->numConstants(); ++i)
-            out.print(anotherComma, inContext(m_codeBlock->constantBuffer(node->startConstant())[i], context));
+            out.print(anotherComma, pointerDumpInContext(freeze(m_codeBlock->constantBuffer(node->startConstant())[i]), context));
         out.print("]");
     }
     if (node->hasIndexingType())
@@ -292,29 +323,36 @@ void Graph::dump(PrintStream& out, const char* prefix, Node* node, DumpContext*
         out.print(comma, "^", node->phi()->index());
     if (node->hasExecutionCounter())
         out.print(comma, RawPointer(node->executionCounter()));
-    if (node->hasVariableWatchpointSet())
-        out.print(comma, RawPointer(node->variableWatchpointSet()));
-    if (node->hasTypedArray())
-        out.print(comma, inContext(JSValue(node->typedArray()), context));
+    if (node->hasWatchpointSet())
+        out.print(comma, RawPointer(node->watchpointSet()));
     if (node->hasStoragePointer())
         out.print(comma, RawPointer(node->storagePointer()));
-    if (op == JSConstant) {
-        out.print(comma, "$", node->constantNumber());
-        JSValue value = valueOfJSConstant(node);
-        out.print(" = ", inContext(value, context));
-    }
-    if (op == WeakJSConstant)
-        out.print(comma, RawPointer(node->weakConstant()), " (", inContext(*node->weakConstant()->structure(), context), ")");
-    if (node->isBranch() || node->isJump())
-        out.print(comma, "T:", *node->takenBlock());
+    if (node->hasObjectMaterializationData())
+        out.print(comma, node->objectMaterializationData());
+    if (node->hasCallVarargsData())
+        out.print(comma, "firstVarArgOffset = ", node->callVarargsData()->firstVarArgOffset);
+    if (node->hasLoadVarargsData()) {
+        LoadVarargsData* data = node->loadVarargsData();
+        out.print(comma, "start = ", data->start, ", count = ", data->count);
+        if (data->machineStart.isValid())
+            out.print(", machineStart = ", data->machineStart);
+        if (data->machineCount.isValid())
+            out.print(", machineCount = ", data->machineCount);
+        out.print(", offset = ", data->offset, ", mandatoryMinimum = ", data->mandatoryMinimum);
+        out.print(", limit = ", data->limit);
+    }
+    if (node->isConstant())
+        out.print(comma, pointerDumpInContext(node->constant(), context));
+    if (node->isJump())
+        out.print(comma, "T:", *node->targetBlock());
     if (node->isBranch())
-        out.print(comma, "F:", *node->notTakenBlock());
+        out.print(comma, "T:", node->branchData()->taken, ", F:", node->branchData()->notTaken);
     if (node->isSwitch()) {
         SwitchData* data = node->switchData();
         out.print(comma, data->kind);
         for (unsigned i = 0; i < data->cases.size(); ++i)
-            out.print(comma, inContext(data->cases[i].value, context), ":", *data->cases[i].target);
-        out.print(comma, "default:", *data->fallThrough);
+            out.print(comma, inContext(data->cases[i].value, context), ":", data->cases[i].target);
+        out.print(comma, "default:", data->fallThrough);
     }
     ClobberSet reads;
     ClobberSet writes;
@@ -323,45 +361,66 @@ void Graph::dump(PrintStream& out, const char* prefix, Node* node, DumpContext*
         out.print(comma, "R:", sortedListDump(reads.direct(), ","));
     if (!writes.isEmpty())
         out.print(comma, "W:", sortedListDump(writes.direct(), ","));
-    out.print(comma, "bc#", node->codeOrigin.bytecodeIndex);
-    
+    ExitMode exitMode = mayExit(*this, node);
+    if (exitMode != DoesNotExit)
+        out.print(comma, exitMode);
+    if (clobbersExitState(*this, node))
+        out.print(comma, "ClobbersExit");
+    if (node->origin.isSet()) {
+        out.print(comma, "bc#", node->origin.semantic.bytecodeIndex);
+        if (node->origin.semantic != node->origin.forExit && node->origin.forExit.isSet())
+            out.print(comma, "exit: ", node->origin.forExit);
+    }
+    if (!node->origin.exitOK)
+        out.print(comma, "ExitInvalid");
     out.print(")");
 
-    if (!skipped) {
-        if (node->hasVariableAccessData(*this))
-            out.print("  predicting ", SpeculationDump(node->variableAccessData()->prediction()));
-        else if (node->hasHeapPrediction())
-            out.print("  predicting ", SpeculationDump(node->getHeapPrediction()));
-    }
+    if (node->hasVariableAccessData(*this) && node->tryGetVariableAccessData())
+        out.print("  predicting ", SpeculationDump(node->tryGetVariableAccessData()->prediction()));
+    else if (node->hasHeapPrediction())
+        out.print("  predicting ", SpeculationDump(node->getHeapPrediction()));
     
     out.print("\n");
 }
 
+bool Graph::terminalsAreValid()
+{
+    for (BasicBlock* block : blocksInNaturalOrder()) {
+        if (!block->terminal())
+            return false;
+    }
+    return true;
+}
+
 void Graph::dumpBlockHeader(PrintStream& out, const char* prefix, BasicBlock* block, PhiNodeDumpMode phiNodeDumpMode, DumpContext* context)
 {
-    out.print(prefix, "Block ", *block, " (", inContext(block->at(0)->codeOrigin, context), "): ", block->isReachable ? "" : "(skipped)", block->isOSRTarget ? " (OSR target)" : "", "\n");
+    out.print(prefix, "Block ", *block, " (", inContext(block->at(0)->origin.semantic, context), "):", block->isReachable ? "" : " (skipped)", block->isOSRTarget ? " (OSR target)" : "", "\n");
+    if (block->executionCount == block->executionCount)
+        out.print(prefix, "  Execution count: ", block->executionCount, "\n");
     out.print(prefix, "  Predecessors:");
     for (size_t i = 0; i < block->predecessors.size(); ++i)
         out.print(" ", *block->predecessors[i]);
     out.print("\n");
-    if (m_dominators.isValid()) {
-        out.print(prefix, "  Dominated by:");
-        for (size_t i = 0; i < m_blocks.size(); ++i) {
-            if (!m_dominators.dominates(i, block->index))
-                continue;
-            out.print(" #", i);
-        }
-        out.print("\n");
-        out.print(prefix, "  Dominates:");
-        for (size_t i = 0; i < m_blocks.size(); ++i) {
-            if (!m_dominators.dominates(block->index, i))
-                continue;
-            out.print(" #", i);
+    out.print(prefix, "  Successors:");
+    if (block->terminal()) {
+        for (BasicBlock* successor : block->successors()) {
+            out.print(" ", *successor);
+            if (m_prePostNumbering)
+                out.print(" (", m_prePostNumbering->edgeKind(block, successor), ")");
         }
-        out.print("\n");
+    } else
+        out.print(" <invalid>");
+    out.print("\n");
+    if (m_dominators && terminalsAreValid()) {
+        out.print(prefix, "  Dominated by: ", m_dominators->dominatorsOf(block), "\n");
+        out.print(prefix, "  Dominates: ", m_dominators->blocksDominatedBy(block), "\n");
+        out.print(prefix, "  Dominance Frontier: ", m_dominators->dominanceFrontierOf(block), "\n");
+        out.print(prefix, "  Iterated Dominance Frontier: ", m_dominators->iteratedDominanceFrontierOf(BlockList(1, block)), "\n");
     }
-    if (m_naturalLoops.isValid()) {
-        if (const NaturalLoop* loop = m_naturalLoops.headerOf(block)) {
+    if (m_prePostNumbering)
+        out.print(prefix, "  Pre/Post Numbering: ", m_prePostNumbering->preNumber(block), "/", m_prePostNumbering->postNumber(block), "\n");
+    if (m_naturalLoops) {
+        if (const NaturalLoop* loop = m_naturalLoops->headerOf(block)) {
             out.print(prefix, "  Loop header, contains:");
             Vector<BlockIndex> sortedBlockList;
             for (unsigned i = 0; i < loop->size(); ++i)
@@ -373,7 +432,7 @@ void Graph::dumpBlockHeader(PrintStream& out, const char* prefix, BasicBlock* bl
         }
         
         Vector<const NaturalLoop*> containingLoops =
-            m_naturalLoops.loopsOf(block);
+            m_naturalLoops->loopsOf(block);
         if (!containingLoops.isEmpty()) {
             out.print(prefix, "  Containing loop headers:");
             for (unsigned i = 0; i < containingLoops.size(); ++i)
@@ -387,7 +446,7 @@ void Graph::dumpBlockHeader(PrintStream& out, const char* prefix, BasicBlock* bl
             Node* phiNode = block->phis[i];
             if (!phiNode->shouldGenerate() && phiNodeDumpMode == DumpLivePhisOnly)
                 continue;
-            out.print(" @", phiNode->index(), "<", phiNode->refCount(), ">->(");
+            out.print(" @", phiNode->index(), "<", phiNode->local(), ",", phiNode->refCount(), ">->(");
             if (phiNode->child1()) {
                 out.print("@", phiNode->child1()->index());
                 if (phiNode->child2()) {
@@ -409,33 +468,48 @@ void Graph::dump(PrintStream& out, DumpContext* context)
     if (!context)
         context = &myContext;
     
-    dataLog("\n");
-    dataLog("DFG for ", CodeBlockWithJITType(m_codeBlock, JITCode::DFGJIT), ":\n");
-    dataLog("  Fixpoint state: ", m_fixpointState, "; Form: ", m_form, "; Unification state: ", m_unificationState, "; Ref count state: ", m_refCountState, "\n");
-    dataLog("\n");
+    out.print("\n");
+    out.print("DFG for ", CodeBlockWithJITType(m_codeBlock, JITCode::DFGJIT), ":\n");
+    out.print("  Fixpoint state: ", m_fixpointState, "; Form: ", m_form, "; Unification state: ", m_unificationState, "; Ref count state: ", m_refCountState, "\n");
+    if (m_form == SSA)
+        out.print("  Argument formats: ", listDump(m_argumentFormats), "\n");
+    else
+        out.print("  Arguments: ", listDump(m_arguments), "\n");
+    out.print("\n");
     
-    Node* lastNode = 0;
+    Node* lastNode = nullptr;
     for (size_t b = 0; b < m_blocks.size(); ++b) {
         BasicBlock* block = m_blocks[b].get();
         if (!block)
             continue;
         dumpBlockHeader(out, "", block, DumpAllPhis, context);
+        out.print("  States: ", block->cfaStructureClobberStateAtHead);
+        if (!block->cfaHasVisited)
+            out.print(", CurrentlyCFAUnreachable");
+        if (!block->intersectionOfCFAHasVisited)
+            out.print(", CFAUnreachable");
+        out.print("\n");
         switch (m_form) {
         case LoadStore:
         case ThreadedCPS: {
-            out.print("  vars before: ");
+            out.print("  Vars Before: ");
             if (block->cfaHasVisited)
                 out.print(inContext(block->valuesAtHead, context));
             else
                 out.print("<empty>");
             out.print("\n");
-            out.print("  var links: ", block->variablesAtHead, "\n");
+            out.print("  Intersected Vars Before: ");
+            if (block->intersectionOfCFAHasVisited)
+                out.print(inContext(block->intersectionOfPastValuesAtHead, context));
+            else
+                out.print("<empty>");
+            out.print("\n");
+            out.print("  Var Links: ", block->variablesAtHead, "\n");
             break;
         }
             
         case SSA: {
             RELEASE_ASSERT(block->ssa);
-            out.print("  Flush format: ", block->ssa->flushAtHead, "\n");
             out.print("  Availability: ", block->ssa->availabilityAtHead, "\n");
             out.print("  Live: ", nodeListDump(block->ssa->liveAtHead), "\n");
             out.print("  Values: ", nodeMapDump(block->ssa->valuesAtHead, context), "\n");
@@ -444,35 +518,45 @@ void Graph::dump(PrintStream& out, DumpContext* context)
         for (size_t i = 0; i < block->size(); ++i) {
             dumpCodeOrigin(out, "", lastNode, block->at(i), context);
             dump(out, "", block->at(i), context);
-            lastNode = block->at(i);
         }
+        out.print("  States: ", block->cfaBranchDirection, ", ", block->cfaStructureClobberStateAtTail);
+        if (!block->cfaDidFinish)
+            out.print(", CFAInvalidated");
+        out.print("\n");
         switch (m_form) {
         case LoadStore:
         case ThreadedCPS: {
-            out.print("  vars after: ");
+            out.print("  Vars After: ");
             if (block->cfaHasVisited)
                 out.print(inContext(block->valuesAtTail, context));
             else
                 out.print("<empty>");
             out.print("\n");
-            out.print("  var links: ", block->variablesAtTail, "\n");
+            out.print("  Var Links: ", block->variablesAtTail, "\n");
             break;
         }
             
         case SSA: {
             RELEASE_ASSERT(block->ssa);
-            out.print("  Flush format: ", block->ssa->flushAtTail, "\n");
             out.print("  Availability: ", block->ssa->availabilityAtTail, "\n");
             out.print("  Live: ", nodeListDump(block->ssa->liveAtTail), "\n");
             out.print("  Values: ", nodeMapDump(block->ssa->valuesAtTail, context), "\n");
             break;
         } }
-        dataLog("\n");
+        out.print("\n");
+    }
+    
+    out.print("GC Values:\n");
+    for (FrozenValue* value : m_frozenValues) {
+        if (value->pointsToHeap())
+            out.print("    ", inContext(*value, &myContext), "\n");
     }
+
+    out.print(inContext(watchpoints(), &myContext));
     
     if (!myContext.isEmpty()) {
-        myContext.dump(WTF::dataFile());
-        dataLog("\n");
+        myContext.dump(out);
+        out.print("\n");
     }
 }
 
@@ -534,6 +618,113 @@ void Graph::resetReachability()
     determineReachability();
 }
 
+namespace {
+
+class RefCountCalculator {
+public:
+    RefCountCalculator(Graph& graph)
+        : m_graph(graph)
+    {
+    }
+    
+    void calculate()
+    {
+        // First reset the counts to 0 for all nodes.
+        for (BlockIndex blockIndex = 0; blockIndex < m_graph.numBlocks(); ++blockIndex) {
+            BasicBlock* block = m_graph.block(blockIndex);
+            if (!block)
+                continue;
+            for (unsigned indexInBlock = block->size(); indexInBlock--;)
+                block->at(indexInBlock)->setRefCount(0);
+            for (unsigned phiIndex = block->phis.size(); phiIndex--;)
+                block->phis[phiIndex]->setRefCount(0);
+        }
+    
+        // Now find the roots:
+        // - Nodes that are must-generate.
+        // - Nodes that are reachable from type checks.
+        // Set their ref counts to 1 and put them on the worklist.
+        for (BlockIndex blockIndex = 0; blockIndex < m_graph.numBlocks(); ++blockIndex) {
+            BasicBlock* block = m_graph.block(blockIndex);
+            if (!block)
+                continue;
+            for (unsigned indexInBlock = block->size(); indexInBlock--;) {
+                Node* node = block->at(indexInBlock);
+                DFG_NODE_DO_TO_CHILDREN(m_graph, node, findTypeCheckRoot);
+                if (!(node->flags() & NodeMustGenerate))
+                    continue;
+                if (!node->postfixRef())
+                    m_worklist.append(node);
+            }
+        }
+        
+        while (!m_worklist.isEmpty()) {
+            while (!m_worklist.isEmpty()) {
+                Node* node = m_worklist.last();
+                m_worklist.removeLast();
+                ASSERT(node->shouldGenerate()); // It should not be on the worklist unless it's ref'ed.
+                DFG_NODE_DO_TO_CHILDREN(m_graph, node, countEdge);
+            }
+            
+            if (m_graph.m_form == SSA) {
+                // Find Phi->Upsilon edges, which are represented as meta-data in the
+                // Upsilon.
+                for (BlockIndex blockIndex = m_graph.numBlocks(); blockIndex--;) {
+                    BasicBlock* block = m_graph.block(blockIndex);
+                    if (!block)
+                        continue;
+                    for (unsigned nodeIndex = block->size(); nodeIndex--;) {
+                        Node* node = block->at(nodeIndex);
+                        if (node->op() != Upsilon)
+                            continue;
+                        if (node->shouldGenerate())
+                            continue;
+                        if (node->phi()->shouldGenerate())
+                            countNode(node);
+                    }
+                }
+            }
+        }
+    }
+    
+private:
+    void findTypeCheckRoot(Node*, Edge edge)
+    {
+        // We may have an "unproved" untyped use for code that is unreachable. The CFA
+        // will just not have gotten around to it.
+        if (edge.isProved() || edge.willNotHaveCheck())
+            return;
+        if (!edge->postfixRef())
+            m_worklist.append(edge.node());
+    }
+    
+    void countNode(Node* node)
+    {
+        if (node->postfixRef())
+            return;
+        m_worklist.append(node);
+    }
+    
+    void countEdge(Node*, Edge edge)
+    {
+        // Don't count edges that are already counted for their type checks.
+        if (!(edge.isProved() || edge.willNotHaveCheck()))
+            return;
+        countNode(edge.node());
+    }
+    
+    Graph& m_graph;
+    Vector<Node*, 128> m_worklist;
+};
+
+} // anonymous namespace
+
+void Graph::computeRefCounts()
+{
+    RefCountCalculator calculator(*this);
+    calculator.calculate();
+}
+
 void Graph::killBlockAndItsContents(BasicBlock* block)
 {
     for (unsigned phiIndex = block->phis.size(); phiIndex--;)
@@ -557,29 +748,15 @@ void Graph::killUnreachableBlocks()
     }
 }
 
-void Graph::resetExitStates()
-{
-    for (BlockIndex blockIndex = 0; blockIndex < m_blocks.size(); ++blockIndex) {
-        BasicBlock* block = m_blocks[blockIndex].get();
-        if (!block)
-            continue;
-        for (unsigned indexInBlock = block->size(); indexInBlock--;)
-            block->at(indexInBlock)->setCanExit(true);
-    }
-}
-
 void Graph::invalidateCFG()
 {
-    m_dominators.invalidate();
-    m_naturalLoops.invalidate();
+    m_dominators = nullptr;
+    m_naturalLoops = nullptr;
+    m_prePostNumbering = nullptr;
 }
 
 void Graph::substituteGetLocal(BasicBlock& block, unsigned startIndexInBlock, VariableAccessData* variableAccessData, Node* newGetLocal)
 {
-    if (variableAccessData->isCaptured()) {
-        // Let CSE worry about this one.
-        return;
-    }
     for (unsigned indexInBlock = startIndexInBlock; indexInBlock < block.size(); ++indexInBlock) {
         Node* node = block[indexInBlock];
         bool shouldContinue = true;
@@ -609,26 +786,37 @@ void Graph::substituteGetLocal(BasicBlock& block, unsigned startIndexInBlock, Va
     }
 }
 
-void Graph::addForDepthFirstSort(Vector<BasicBlock*>& result, Vector<BasicBlock*, 16>& worklist, HashSet<BasicBlock*>& seen, BasicBlock* block)
+BlockList Graph::blocksInPreOrder()
 {
-    if (seen.contains(block))
-        return;
-    
-    result.append(block);
-    worklist.append(block);
-    seen.add(block);
+    BlockList result;
+    BlockWorklist worklist;
+    worklist.push(block(0));
+    while (BasicBlock* block = worklist.pop()) {
+        result.append(block);
+        for (unsigned i = block->numSuccessors(); i--;)
+            worklist.push(block->successor(i));
+    }
+    return result;
 }
 
-void Graph::getBlocksInDepthFirstOrder(Vector<BasicBlock*>& result)
+BlockList Graph::blocksInPostOrder()
 {
-    Vector<BasicBlock*, 16> worklist;
-    HashSet<BasicBlock*> seen;
-    addForDepthFirstSort(result, worklist, seen, block(0));
-    while (!worklist.isEmpty()) {
-        BasicBlock* block = worklist.takeLast();
-        for (unsigned i = block->numSuccessors(); i--;)
-            addForDepthFirstSort(result, worklist, seen, block->successor(i));
+    BlockList result;
+    PostOrderBlockWorklist worklist;
+    worklist.push(block(0));
+    while (BlockWithOrder item = worklist.pop()) {
+        switch (item.order) {
+        case VisitOrder::Pre:
+            worklist.pushPost(item.node);
+            for (unsigned i = item.node->numSuccessors(); i--;)
+                worklist.push(item.node->successor(i));
+            break;
+        case VisitOrder::Post:
+            result.append(item.node);
+            break;
+        }
     }
+    return result;
 }
 
 void Graph::clearReplacements()
@@ -638,9 +826,22 @@ void Graph::clearReplacements()
         if (!block)
             continue;
         for (unsigned phiIndex = block->phis.size(); phiIndex--;)
-            block->phis[phiIndex]->misc.replacement = 0;
+            block->phis[phiIndex]->setReplacement(nullptr);
         for (unsigned nodeIndex = block->size(); nodeIndex--;)
-            block->at(nodeIndex)->misc.replacement = 0;
+            block->at(nodeIndex)->setReplacement(nullptr);
+    }
+}
+
+void Graph::clearEpochs()
+{
+    for (BlockIndex blockIndex = numBlocks(); blockIndex--;) {
+        BasicBlock* block = m_blocks[blockIndex].get();
+        if (!block)
+            continue;
+        for (unsigned phiIndex = block->phis.size(); phiIndex--;)
+            block->phis[phiIndex]->setEpoch(Epoch());
+        for (unsigned nodeIndex = block->size(); nodeIndex--;)
+            block->at(nodeIndex)->setEpoch(Epoch());
     }
 }
 
@@ -651,10 +852,79 @@ void Graph::initializeNodeOwners()
         if (!block)
             continue;
         for (unsigned phiIndex = block->phis.size(); phiIndex--;)
-            block->phis[phiIndex]->misc.owner = block;
+            block->phis[phiIndex]->owner = block;
+        for (unsigned nodeIndex = block->size(); nodeIndex--;)
+            block->at(nodeIndex)->owner = block;
+    }
+}
+
+void Graph::clearFlagsOnAllNodes(NodeFlags flags)
+{
+    for (BlockIndex blockIndex = numBlocks(); blockIndex--;) {
+        BasicBlock* block = m_blocks[blockIndex].get();
+        if (!block)
+            continue;
+        for (unsigned phiIndex = block->phis.size(); phiIndex--;)
+            block->phis[phiIndex]->clearFlags(flags);
         for (unsigned nodeIndex = block->size(); nodeIndex--;)
-            block->at(nodeIndex)->misc.owner = block;
+            block->at(nodeIndex)->clearFlags(flags);
+    }
+}
+
+bool Graph::watchCondition(const ObjectPropertyCondition& key)
+{
+    if (!key.isWatchable())
+        return false;
+    
+    m_plan.weakReferences.addLazily(key.object());
+    if (key.hasPrototype())
+        m_plan.weakReferences.addLazily(key.prototype());
+    if (key.hasRequiredValue())
+        m_plan.weakReferences.addLazily(key.requiredValue());
+    
+    m_plan.watchpoints.addLazily(key);
+
+    if (key.kind() == PropertyCondition::Presence)
+        m_safeToLoad.add(std::make_pair(key.object(), key.offset()));
+    
+    return true;
+}
+
+bool Graph::isSafeToLoad(JSObject* base, PropertyOffset offset)
+{
+    return m_safeToLoad.contains(std::make_pair(base, offset));
+}
+
+InferredType::Descriptor Graph::inferredTypeFor(const PropertyTypeKey& key)
+{
+    assertIsRegistered(key.structure());
+    
+    auto iter = m_inferredTypes.find(key);
+    if (iter != m_inferredTypes.end())
+        return iter->value;
+
+    InferredType* typeObject = key.structure()->inferredTypeFor(key.uid());
+    if (!typeObject) {
+        m_inferredTypes.add(key, InferredType::Top);
+        return InferredType::Top;
     }
+
+    InferredType::Descriptor typeDescriptor = typeObject->descriptor();
+    if (typeDescriptor.kind() == InferredType::Top) {
+        m_inferredTypes.add(key, InferredType::Top);
+        return InferredType::Top;
+    }
+    
+    m_inferredTypes.add(key, typeDescriptor);
+
+    m_plan.weakReferences.addLazily(typeObject);
+    registerInferredType(typeDescriptor);
+
+    // Note that we may already be watching this desired inferred type, because multiple structures may
+    // point to the same InferredType instance.
+    m_plan.watchpoints.addLazily(DesiredInferredType(typeObject, typeDescriptor));
+
+    return typeDescriptor;
 }
 
 FullBytecodeLiveness& Graph::livenessFor(CodeBlock* codeBlock)
@@ -666,7 +936,7 @@ FullBytecodeLiveness& Graph::livenessFor(CodeBlock* codeBlock)
     std::unique_ptr<FullBytecodeLiveness> liveness = std::make_unique<FullBytecodeLiveness>();
     codeBlock->livenessAnalysis().computeFullLiveness(*liveness);
     FullBytecodeLiveness& result = *liveness;
-    m_bytecodeLiveness.add(codeBlock, std::move(liveness));
+    m_bytecodeLiveness.add(codeBlock, WTFMove(liveness));
     return result;
 }
 
@@ -675,49 +945,98 @@ FullBytecodeLiveness& Graph::livenessFor(InlineCallFrame* inlineCallFrame)
     return livenessFor(baselineCodeBlockFor(inlineCallFrame));
 }
 
+BytecodeKills& Graph::killsFor(CodeBlock* codeBlock)
+{
+    HashMap<CodeBlock*, std::unique_ptr<BytecodeKills>>::iterator iter = m_bytecodeKills.find(codeBlock);
+    if (iter != m_bytecodeKills.end())
+        return *iter->value;
+    
+    std::unique_ptr<BytecodeKills> kills = std::make_unique<BytecodeKills>();
+    codeBlock->livenessAnalysis().computeKills(*kills);
+    BytecodeKills& result = *kills;
+    m_bytecodeKills.add(codeBlock, WTFMove(kills));
+    return result;
+}
+
+BytecodeKills& Graph::killsFor(InlineCallFrame* inlineCallFrame)
+{
+    return killsFor(baselineCodeBlockFor(inlineCallFrame));
+}
+
 bool Graph::isLiveInBytecode(VirtualRegister operand, CodeOrigin codeOrigin)
 {
+    CodeOrigin* codeOriginPtr = &codeOrigin;
     for (;;) {
-        if (operand.offset() < codeOrigin.stackOffset() + JSStack::CallFrameHeaderSize) {
-            VirtualRegister reg = VirtualRegister(
-                operand.offset() - codeOrigin.stackOffset());
-            
+        VirtualRegister reg = VirtualRegister(
+            operand.offset() - codeOriginPtr->stackOffset());
+        
+        if (operand.offset() < codeOriginPtr->stackOffset() + JSStack::CallFrameHeaderSize) {
             if (reg.isArgument()) {
                 RELEASE_ASSERT(reg.offset() < JSStack::CallFrameHeaderSize);
                 
-                if (!codeOrigin.inlineCallFrame->isClosureCall)
-                    return false;
-                
-                if (reg.offset() == JSStack::Callee)
+                if (codeOriginPtr->inlineCallFrame->isClosureCall
+                    && reg.offset() == JSStack::Callee)
                     return true;
-                if (reg.offset() == JSStack::ScopeChain)
+                
+                if (codeOriginPtr->inlineCallFrame->isVarargs()
+                    && reg.offset() == JSStack::ArgumentCount)
                     return true;
                 
                 return false;
             }
             
-            return livenessFor(codeOrigin.inlineCallFrame).operandIsLive(
-                reg.offset(), codeOrigin.bytecodeIndex);
+            return livenessFor(codeOriginPtr->inlineCallFrame).operandIsLive(
+                reg.offset(), codeOriginPtr->bytecodeIndex);
         }
         
-        if (!codeOrigin.inlineCallFrame)
+        InlineCallFrame* inlineCallFrame = codeOriginPtr->inlineCallFrame;
+        if (!inlineCallFrame)
             break;
+
+        // Arguments are always live. This would be redundant if it wasn't for our
+        // op_call_varargs inlining.
+        if (reg.isArgument()
+            && static_cast<size_t>(reg.toArgument()) < inlineCallFrame->arguments.size())
+            return true;
         
-        codeOrigin = codeOrigin.inlineCallFrame->caller;
+        codeOriginPtr = inlineCallFrame->getCallerSkippingTailCalls();
+
+        // The first inline call frame could be an inline tail call
+        if (!codeOriginPtr)
+            break;
     }
     
     return true;
 }
 
+BitVector Graph::localsLiveInBytecode(CodeOrigin codeOrigin)
+{
+    BitVector result;
+    result.ensureSize(block(0)->variablesAtHead.numberOfLocals());
+    forAllLocalsLiveInBytecode(
+        codeOrigin,
+        [&] (VirtualRegister reg) {
+            ASSERT(reg.isLocal());
+            result.quickSet(reg.toLocal());
+        });
+    return result;
+}
+
 unsigned Graph::frameRegisterCount()
 {
-    return m_nextMachineLocal + m_parameterSlots;
+    unsigned result = m_nextMachineLocal + std::max(m_parameterSlots, static_cast<unsigned>(maxFrameExtentForSlowPathCallInRegisters));
+    return roundLocalRegisterCountForFramePointerOffset(result);
+}
+
+unsigned Graph::stackPointerOffset()
+{
+    return virtualRegisterForLocal(frameRegisterCount() - 1).offset();
 }
 
 unsigned Graph::requiredRegisterCountForExit()
 {
     unsigned count = JIT::frameRegisterCountFor(m_profiledBlock);
-    for (InlineCallFrameSet::iterator iter = m_inlineCallFrames->begin(); !!iter; ++iter) {
+    for (InlineCallFrameSet::iterator iter = m_plan.inlineCallFrames->begin(); !!iter; ++iter) {
         InlineCallFrame* inlineCallFrame = *iter;
         CodeBlock* codeBlock = baselineCodeBlockForInlineCallFrame(inlineCallFrame);
         unsigned requiredCount = VirtualRegister(inlineCallFrame->stackOffset).toLocal() + 1 + JIT::frameRegisterCountFor(codeBlock);
@@ -731,47 +1050,512 @@ unsigned Graph::requiredRegisterCountForExecutionAndExit()
     return std::max(frameRegisterCount(), requiredRegisterCountForExit());
 }
 
-JSActivation* Graph::tryGetActivation(Node* node)
+JSValue Graph::tryGetConstantProperty(
+    JSValue base, const StructureSet& structureSet, PropertyOffset offset)
 {
-    if (!node->hasConstant())
-        return 0;
-    return jsDynamicCast<JSActivation*>(valueOfJSConstant(node));
+    if (!base || !base.isObject())
+        return JSValue();
+    
+    JSObject* object = asObject(base);
+    
+    for (unsigned i = structureSet.size(); i--;) {
+        Structure* structure = structureSet[i];
+        assertIsRegistered(structure);
+        
+        WatchpointSet* set = structure->propertyReplacementWatchpointSet(offset);
+        if (!set || !set->isStillValid())
+            return JSValue();
+        
+        ASSERT(structure->isValidOffset(offset));
+        ASSERT(!structure->isUncacheableDictionary());
+        
+        watchpoints().addLazily(set);
+    }
+    
+    // What follows may require some extra thought. We need this load to load a valid JSValue. If
+    // our profiling makes sense and we're still on track to generate code that won't be
+    // invalidated, then we have nothing to worry about. We do, however, have to worry about
+    // loading - and then using - an invalid JSValue in the case that unbeknownst to us our code
+    // is doomed.
+    //
+    // One argument in favor of this code is that it should definitely work because the butterfly
+    // is always set before the structure. However, we don't currently have a fence between those
+    // stores. It's not clear if this matters, however. We don't ever shrink the property storage.
+    // So, for this to fail, you'd need an access on a constant object pointer such that the inline
+    // caches told us that the object had a structure that it did not *yet* have, and then later,
+    // the object transitioned to that structure that the inline caches had alraedy seen. And then
+    // the processor reordered the stores. Seems unlikely and difficult to test. I believe that
+    // this is worth revisiting but it isn't worth losing sleep over. Filed:
+    // https://bugs.webkit.org/show_bug.cgi?id=134641
+    //
+    // For now, we just do the minimal thing: defend against the structure right now being
+    // incompatible with the getDirect we're trying to do. The easiest way to do that is to
+    // determine if the structure belongs to the proven set.
+    
+    if (!structureSet.contains(object->structure()))
+        return JSValue();
+    
+    return object->getDirect(offset);
+}
+
+JSValue Graph::tryGetConstantProperty(JSValue base, Structure* structure, PropertyOffset offset)
+{
+    return tryGetConstantProperty(base, StructureSet(structure), offset);
 }
 
-WriteBarrierBase<Unknown>* Graph::tryGetRegisters(Node* node)
+JSValue Graph::tryGetConstantProperty(
+    JSValue base, const StructureAbstractValue& structure, PropertyOffset offset)
 {
-    JSActivation* activation = tryGetActivation(node);
+    if (structure.isInfinite()) {
+        // FIXME: If we just converted the offset to a uid, we could do ObjectPropertyCondition
+        // watching to constant-fold the property.
+        // https://bugs.webkit.org/show_bug.cgi?id=147271
+        return JSValue();
+    }
+    
+    return tryGetConstantProperty(base, structure.set(), offset);
+}
+
+JSValue Graph::tryGetConstantProperty(const AbstractValue& base, PropertyOffset offset)
+{
+    return tryGetConstantProperty(base.m_value, base.m_structure, offset);
+}
+
+AbstractValue Graph::inferredValueForProperty(
+    const StructureSet& base, UniquedStringImpl* uid, StructureClobberState clobberState)
+{
+    AbstractValue result;
+    base.forEach(
+        [&] (Structure* structure) {
+            AbstractValue value;
+            value.set(*this, inferredTypeForProperty(structure, uid));
+            result.merge(value);
+        });
+    if (clobberState == StructuresAreClobbered)
+        result.clobberStructures();
+    return result;
+}
+
+AbstractValue Graph::inferredValueForProperty(
+    const AbstractValue& base, UniquedStringImpl* uid, PropertyOffset offset,
+    StructureClobberState clobberState)
+{
+    if (JSValue value = tryGetConstantProperty(base, offset)) {
+        AbstractValue result;
+        result.set(*this, *freeze(value), clobberState);
+        return result;
+    }
+
+    if (base.m_structure.isFinite())
+        return inferredValueForProperty(base.m_structure.set(), uid, clobberState);
+
+    return AbstractValue::heapTop();
+}
+
+JSValue Graph::tryGetConstantClosureVar(JSValue base, ScopeOffset offset)
+{
+    // This has an awesome concurrency story. See comment for GetGlobalVar in ByteCodeParser.
+    
+    if (!base)
+        return JSValue();
+    
+    JSLexicalEnvironment* activation = jsDynamicCast<JSLexicalEnvironment*>(base);
     if (!activation)
-        return 0;
-    if (!activation->isTornOff())
-        return 0;
-    return activation->registers();
+        return JSValue();
+    
+    SymbolTable* symbolTable = activation->symbolTable();
+    JSValue value;
+    WatchpointSet* set;
+    {
+        ConcurrentJITLocker locker(symbolTable->m_lock);
+        
+        SymbolTableEntry* entry = symbolTable->entryFor(locker, offset);
+        if (!entry)
+            return JSValue();
+        
+        set = entry->watchpointSet();
+        if (!set)
+            return JSValue();
+        
+        if (set->state() != IsWatched)
+            return JSValue();
+        
+        ASSERT(entry->scopeOffset() == offset);
+        value = activation->variableAt(offset).get();
+        if (!value)
+            return JSValue();
+    }
+    
+    watchpoints().addLazily(set);
+    
+    return value;
 }
 
-JSArrayBufferView* Graph::tryGetFoldableView(Node* node)
+JSValue Graph::tryGetConstantClosureVar(const AbstractValue& value, ScopeOffset offset)
+{
+    return tryGetConstantClosureVar(value.m_value, offset);
+}
+
+JSValue Graph::tryGetConstantClosureVar(Node* node, ScopeOffset offset)
 {
     if (!node->hasConstant())
-        return 0;
-    JSArrayBufferView* view = jsDynamicCast<JSArrayBufferView*>(valueOfJSConstant(node));
-    if (!view)
-        return 0;
-    if (!watchpoints().isStillValid(view))
-        return 0;
+        return JSValue();
+    return tryGetConstantClosureVar(node->asJSValue(), offset);
+}
+
+JSArrayBufferView* Graph::tryGetFoldableView(JSValue value)
+{
+    if (!value)
+        return nullptr;
+    JSArrayBufferView* view = jsDynamicCast<JSArrayBufferView*>(value);
+    if (!value)
+        return nullptr;
+    if (!view->length())
+        return nullptr;
+    WTF::loadLoadFence();
+    watchpoints().addLazily(view);
     return view;
 }
 
-JSArrayBufferView* Graph::tryGetFoldableView(Node* node, ArrayMode arrayMode)
+JSArrayBufferView* Graph::tryGetFoldableView(JSValue value, ArrayMode arrayMode)
+{
+    if (arrayMode.type() != Array::AnyTypedArray && arrayMode.typedArrayType() == NotTypedArray)
+        return nullptr;
+    return tryGetFoldableView(value);
+}
+
+void Graph::registerFrozenValues()
+{
+    m_codeBlock->constants().resize(0);
+    m_codeBlock->constantsSourceCodeRepresentation().resize(0);
+    for (FrozenValue* value : m_frozenValues) {
+        if (!value->pointsToHeap())
+            continue;
+        
+        ASSERT(value->structure());
+        ASSERT(m_plan.weakReferences.contains(value->structure()));
+        
+        switch (value->strength()) {
+        case WeakValue: {
+            m_plan.weakReferences.addLazily(value->value().asCell());
+            break;
+        }
+        case StrongValue: {
+            unsigned constantIndex = m_codeBlock->addConstantLazily();
+            // We already have a barrier on the code block.
+            m_codeBlock->constants()[constantIndex].setWithoutWriteBarrier(value->value());
+            break;
+        } }
+    }
+    m_codeBlock->constants().shrinkToFit();
+    m_codeBlock->constantsSourceCodeRepresentation().shrinkToFit();
+}
+
+void Graph::visitChildren(SlotVisitor& visitor)
+{
+    for (FrozenValue* value : m_frozenValues) {
+        visitor.appendUnbarrieredReadOnlyValue(value->value());
+        visitor.appendUnbarrieredReadOnlyPointer(value->structure());
+    }
+    
+    for (BlockIndex blockIndex = numBlocks(); blockIndex--;) {
+        BasicBlock* block = this->block(blockIndex);
+        if (!block)
+            continue;
+        
+        for (unsigned nodeIndex = 0; nodeIndex < block->size(); ++nodeIndex) {
+            Node* node = block->at(nodeIndex);
+            
+            switch (node->op()) {
+            case CheckStructure:
+                for (unsigned i = node->structureSet().size(); i--;)
+                    visitor.appendUnbarrieredReadOnlyPointer(node->structureSet()[i]);
+                break;
+                
+            case NewObject:
+            case ArrayifyToStructure:
+            case NewStringObject:
+                visitor.appendUnbarrieredReadOnlyPointer(node->structure());
+                break;
+                
+            case PutStructure:
+            case AllocatePropertyStorage:
+            case ReallocatePropertyStorage:
+                visitor.appendUnbarrieredReadOnlyPointer(
+                    node->transition()->previous);
+                visitor.appendUnbarrieredReadOnlyPointer(
+                    node->transition()->next);
+                break;
+                
+            case MultiGetByOffset:
+                for (const MultiGetByOffsetCase& getCase : node->multiGetByOffsetData().cases) {
+                    for (Structure* structure : getCase.set())
+                        visitor.appendUnbarrieredReadOnlyPointer(structure);
+                }
+                break;
+                    
+            case MultiPutByOffset:
+                for (unsigned i = node->multiPutByOffsetData().variants.size(); i--;) {
+                    PutByIdVariant& variant = node->multiPutByOffsetData().variants[i];
+                    const StructureSet& set = variant.oldStructure();
+                    for (unsigned j = set.size(); j--;)
+                        visitor.appendUnbarrieredReadOnlyPointer(set[j]);
+                    if (variant.kind() == PutByIdVariant::Transition)
+                        visitor.appendUnbarrieredReadOnlyPointer(variant.newStructure());
+                }
+                break;
+                
+            default:
+                break;
+            }
+        }
+    }
+}
+
+FrozenValue* Graph::freeze(JSValue value)
+{
+    if (UNLIKELY(!value))
+        return FrozenValue::emptySingleton();
+    
+    auto result = m_frozenValueMap.add(JSValue::encode(value), nullptr);
+    if (LIKELY(!result.isNewEntry))
+        return result.iterator->value;
+
+    if (value.isUInt32())
+        m_uint32ValuesInUse.append(value.asUInt32());
+    
+    FrozenValue frozenValue = FrozenValue::freeze(value);
+    if (Structure* structure = frozenValue.structure())
+        registerStructure(structure);
+    
+    return result.iterator->value = m_frozenValues.add(frozenValue);
+}
+
+FrozenValue* Graph::freezeStrong(JSValue value)
+{
+    FrozenValue* result = freeze(value);
+    result->strengthenTo(StrongValue);
+    return result;
+}
+
+void Graph::convertToConstant(Node* node, FrozenValue* value)
+{
+    if (value->structure())
+        assertIsRegistered(value->structure());
+    node->convertToConstant(value);
+}
+
+void Graph::convertToConstant(Node* node, JSValue value)
+{
+    convertToConstant(node, freeze(value));
+}
+
+void Graph::convertToStrongConstant(Node* node, JSValue value)
+{
+    convertToConstant(node, freezeStrong(value));
+}
+
+StructureRegistrationResult Graph::registerStructure(Structure* structure)
+{
+    m_plan.weakReferences.addLazily(structure);
+    if (m_plan.watchpoints.consider(structure))
+        return StructureRegisteredAndWatched;
+    return StructureRegisteredNormally;
+}
+
+void Graph::assertIsRegistered(Structure* structure)
+{
+    // It's convenient to be able to call this with a maybe-null structure.
+    if (!structure)
+        return;
+    
+    DFG_ASSERT(*this, nullptr, m_plan.weakReferences.contains(structure));
+    
+    if (!structure->dfgShouldWatch())
+        return;
+    if (watchpoints().isWatched(structure->transitionWatchpointSet()))
+        return;
+    
+    DFG_CRASH(*this, nullptr, toCString("Structure ", pointerDump(structure), " is watchable but isn't being watched.").data());
+}
+
+NO_RETURN_DUE_TO_CRASH static void crash(
+    Graph& graph, const CString& whileText, const char* file, int line, const char* function,
+    const char* assertion)
+{
+    startCrashing();
+    dataLog("DFG ASSERTION FAILED: ", assertion, "\n");
+    dataLog(file, "(", line, ") : ", function, "\n");
+    dataLog("\n");
+    dataLog(whileText);
+    dataLog("Graph at time of failure:\n");
+    graph.dump();
+    dataLog("\n");
+    dataLog("DFG ASSERTION FAILED: ", assertion, "\n");
+    dataLog(file, "(", line, ") : ", function, "\n");
+    CRASH_WITH_SECURITY_IMPLICATION();
+}
+
+void Graph::handleAssertionFailure(
+    std::nullptr_t, const char* file, int line, const char* function, const char* assertion)
+{
+    crash(*this, "", file, line, function, assertion);
+}
+
+void Graph::handleAssertionFailure(
+    Node* node, const char* file, int line, const char* function, const char* assertion)
+{
+    crash(*this, toCString("While handling node ", node, "\n\n"), file, line, function, assertion);
+}
+
+void Graph::handleAssertionFailure(
+    BasicBlock* block, const char* file, int line, const char* function, const char* assertion)
+{
+    crash(*this, toCString("While handling block ", pointerDump(block), "\n\n"), file, line, function, assertion);
+}
+
+void Graph::ensureDominators()
+{
+    if (!m_dominators)
+        m_dominators = std::make_unique<Dominators>(*this);
+}
+
+void Graph::ensurePrePostNumbering()
+{
+    if (!m_prePostNumbering)
+        m_prePostNumbering = std::make_unique<PrePostNumbering>(*this);
+}
+
+void Graph::ensureNaturalLoops()
+{
+    ensureDominators();
+    if (!m_naturalLoops)
+        m_naturalLoops = std::make_unique<NaturalLoops>(*this);
+}
+
+ValueProfile* Graph::valueProfileFor(Node* node)
+{
+    if (!node)
+        return nullptr;
+        
+    CodeBlock* profiledBlock = baselineCodeBlockFor(node->origin.semantic);
+        
+    if (node->hasLocal(*this)) {
+        if (!node->local().isArgument())
+            return nullptr;
+        int argument = node->local().toArgument();
+        Node* argumentNode = m_arguments[argument];
+        if (!argumentNode)
+            return nullptr;
+        if (node->variableAccessData() != argumentNode->variableAccessData())
+            return nullptr;
+        return profiledBlock->valueProfileForArgument(argument);
+    }
+        
+    if (node->hasHeapPrediction())
+        return profiledBlock->valueProfileForBytecodeOffset(node->origin.semantic.bytecodeIndex);
+        
+    return nullptr;
+}
+
+MethodOfGettingAValueProfile Graph::methodOfGettingAValueProfileFor(Node* node)
 {
-    if (arrayMode.typedArrayType() == NotTypedArray)
-        return 0;
-    return tryGetFoldableView(node);
+    if (!node)
+        return MethodOfGettingAValueProfile();
+    
+    if (ValueProfile* valueProfile = valueProfileFor(node))
+        return MethodOfGettingAValueProfile(valueProfile);
+    
+    if (node->op() == GetLocal) {
+        CodeBlock* profiledBlock = baselineCodeBlockFor(node->origin.semantic);
+        
+        return MethodOfGettingAValueProfile::fromLazyOperand(
+            profiledBlock,
+            LazyOperandValueProfileKey(
+                node->origin.semantic.bytecodeIndex, node->local()));
+    }
+    
+    return MethodOfGettingAValueProfile();
 }
 
-JSArrayBufferView* Graph::tryGetFoldableViewForChild1(Node* node)
+bool Graph::isStringPrototypeMethodSane(JSObject* stringPrototype, Structure* stringPrototypeStructure, UniquedStringImpl* uid)
 {
-    return tryGetFoldableView(child(node, 0).node(), node->arrayMode());
+    unsigned attributesUnused;
+    PropertyOffset offset = stringPrototypeStructure->getConcurrently(uid, attributesUnused);
+    if (!isValidOffset(offset))
+        return false;
+
+    JSValue value = tryGetConstantProperty(stringPrototype, stringPrototypeStructure, offset);
+    if (!value)
+        return false;
+
+    JSFunction* function = jsDynamicCast<JSFunction*>(value);
+    if (!function)
+        return false;
+
+    if (function->executable()->intrinsicFor(CodeForCall) != StringPrototypeValueOfIntrinsic)
+        return false;
+    
+    return true;
+}
+
+bool Graph::canOptimizeStringObjectAccess(const CodeOrigin& codeOrigin)
+{
+    if (hasExitSite(codeOrigin, NotStringObject))
+        return false;
+
+    Structure* stringObjectStructure = globalObjectFor(codeOrigin)->stringObjectStructure();
+    registerStructure(stringObjectStructure);
+    ASSERT(stringObjectStructure->storedPrototype().isObject());
+    ASSERT(stringObjectStructure->storedPrototype().asCell()->classInfo() == StringPrototype::info());
+
+    FrozenValue* stringPrototypeObjectValue = freeze(stringObjectStructure->storedPrototype());
+    StringPrototype* stringPrototypeObject = stringPrototypeObjectValue->dynamicCast<StringPrototype*>();
+    Structure* stringPrototypeStructure = stringPrototypeObjectValue->structure();
+    if (registerStructure(stringPrototypeStructure) != StructureRegisteredAndWatched)
+        return false;
+
+    if (stringPrototypeStructure->isDictionary())
+        return false;
+
+    // We're being conservative here. We want DFG's ToString on StringObject to be
+    // used in both numeric contexts (that would call valueOf()) and string contexts
+    // (that would call toString()). We don't want the DFG to have to distinguish
+    // between the two, just because that seems like it would get confusing. So we
+    // just require both methods to be sane.
+    if (!isStringPrototypeMethodSane(stringPrototypeObject, stringPrototypeStructure, m_vm.propertyNames->valueOf.impl()))
+        return false;
+    if (!isStringPrototypeMethodSane(stringPrototypeObject, stringPrototypeStructure, m_vm.propertyNames->toString.impl()))
+        return false;
+
+    return true;
+}
+
+bool Graph::willCatchExceptionInMachineFrame(CodeOrigin codeOrigin, CodeOrigin& opCatchOriginOut, HandlerInfo*& catchHandlerOut)
+{
+    if (!m_hasExceptionHandlers)
+        return false;
+
+    unsigned bytecodeIndexToCheck = codeOrigin.bytecodeIndex;
+    while (1) {
+        InlineCallFrame* inlineCallFrame = codeOrigin.inlineCallFrame;
+        CodeBlock* codeBlock = baselineCodeBlockFor(inlineCallFrame);
+        if (HandlerInfo* handler = codeBlock->handlerForBytecodeOffset(bytecodeIndexToCheck)) {
+            opCatchOriginOut = CodeOrigin(handler->target, inlineCallFrame);
+            catchHandlerOut = handler;
+            return true;
+        }
+
+        if (!inlineCallFrame)
+            return false;
+
+        bytecodeIndexToCheck = inlineCallFrame->directCaller.bytecodeIndex;
+        codeOrigin = codeOrigin.inlineCallFrame->directCaller;
+    }
+
+    RELEASE_ASSERT_NOT_REACHED();
 }
 
 } } // namespace JSC::DFG
 
-#endif
+#endif // ENABLE(DFG_JIT)