webkitgtk-2.16.5HEADwebkitgtk-2.16.5master

1 files changed, 338 insertions, 93 deletions

diff --git a/Source/JavaScriptCore/dfg/DFGJITCompiler.cpp b/Source/JavaScriptCore/dfg/DFGJITCompiler.cpp
index 2934d2ba9..db5e525ff 100644
--- a/Source/JavaScriptCore/dfg/DFGJITCompiler.cpp
+++ b/Source/JavaScriptCore/dfg/DFGJITCompiler.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2011, 2013 Apple Inc. All rights reserved.
+ * Copyright (C) 2011, 2013-2016 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -39,9 +39,12 @@
 #include "DFGSlowPathGenerator.h"
 #include "DFGSpeculativeJIT.h"
 #include "DFGThunks.h"
+#include "JSCInlines.h"
 #include "JSCJSValueInlines.h"
-#include "VM.h"
 #include "LinkBuffer.h"
+#include "MaxFrameExtentForSlowPathCall.h"
+#include "StructureStubInfo.h"
+#include "VM.h"
 
 namespace JSC { namespace DFG {
 
@@ -50,9 +53,15 @@ JITCompiler::JITCompiler(Graph& dfg)
     , m_graph(dfg)
     , m_jitCode(adoptRef(new JITCode()))
     , m_blockHeads(dfg.numBlocks())
+    , m_pcToCodeOriginMapBuilder(dfg.m_vm)
 {
-    if (shouldShowDisassembly() || m_graph.m_vm.m_perBytecodeProfiler)
-        m_disassembler = adoptPtr(new Disassembler(dfg));
+    if (shouldDumpDisassembly() || m_graph.m_vm.m_perBytecodeProfiler)
+        m_disassembler = std::make_unique<Disassembler>(dfg);
+#if ENABLE(FTL_JIT)
+    m_jitCode->tierUpInLoopHierarchy = WTFMove(m_graph.m_plan.tierUpInLoopHierarchy);
+    for (unsigned tierUpBytecode : m_graph.m_plan.tierUpAndOSREnterBytecodes)
+        m_jitCode->tierUpEntryTriggers.add(tierUpBytecode, JITCode::TriggerReason::DontTrigger);
+#endif
 }
 
 JITCompiler::~JITCompiler()
@@ -83,6 +92,7 @@ void JITCompiler::linkOSRExits()
             failureJumps.link(this);
         else
             info.m_replacementDestination = label();
+
         jitAssertHasValidCallFrame();
         store32(TrustedImm32(i), &vm()->osrExitIndex);
         exit.setPatchableCodeOffset(patchableJump());
@@ -92,15 +102,27 @@ void JITCompiler::linkOSRExits()
 void JITCompiler::compileEntry()
 {
     // This code currently matches the old JIT. In the function header we need to
-    // pop the return address (since we do not allow any recursion on the machine
-    // stack), and perform a fast stack check.
+    // save return address and call frame via the prologue and perform a fast stack check.
     // FIXME: https://bugs.webkit.org/show_bug.cgi?id=56292
     // We'll need to convert the remaining cti_ style calls (specifically the stack
     // check) which will be dependent on stack layout. (We'd need to account for this in
     // both normal return code and when jumping to an exception handler).
-    preserveReturnAddressAfterCall(GPRInfo::regT2);
-    emitPutReturnPCToCallFrameHeader(GPRInfo::regT2);
-    emitPutImmediateToCallFrameHeader(m_codeBlock, JSStack::CodeBlock);
+    emitFunctionPrologue();
+    emitPutToCallFrameHeader(m_codeBlock, CallFrameSlot::codeBlock);
+}
+
+void JITCompiler::compileSetupRegistersForEntry()
+{
+    emitSaveCalleeSaves();
+    emitMaterializeTagCheckRegisters();    
+}
+
+void JITCompiler::compileEntryExecutionFlag()
+{
+#if ENABLE(FTL_JIT)
+    if (m_graph.m_plan.canTierUpAndOSREnter())
+        store8(TrustedImm32(0), &m_jitCode->neverExecutedEntry);
+#endif // ENABLE(FTL_JIT)
 }
 
 void JITCompiler::compileBody()
@@ -114,32 +136,44 @@ void JITCompiler::compileBody()
 
 void JITCompiler::compileExceptionHandlers()
 {
-    if (m_exceptionChecks.empty() && m_exceptionChecksWithCallFrameRollback.empty())
-        return;
-
-    Jump doLookup;
-
     if (!m_exceptionChecksWithCallFrameRollback.empty()) {
         m_exceptionChecksWithCallFrameRollback.link(this);
-        emitGetCallerFrameFromCallFrameHeaderPtr(GPRInfo::argumentGPR0);
-        doLookup = jump();
+
+        copyCalleeSavesToVMEntryFrameCalleeSavesBuffer();
+
+        // lookupExceptionHandlerFromCallerFrame is passed two arguments, the VM and the exec (the CallFrame*).
+        move(TrustedImmPtr(vm()), GPRInfo::argumentGPR0);
+        move(GPRInfo::callFrameRegister, GPRInfo::argumentGPR1);
+        addPtr(TrustedImm32(m_graph.stackPointerOffset() * sizeof(Register)), GPRInfo::callFrameRegister, stackPointerRegister);
+
+#if CPU(X86)
+        // FIXME: should use the call abstraction, but this is currently in the SpeculativeJIT layer!
+        poke(GPRInfo::argumentGPR0);
+        poke(GPRInfo::argumentGPR1, 1);
+#endif
+        m_calls.append(CallLinkRecord(call(), lookupExceptionHandlerFromCallerFrame));
+
+        jumpToExceptionHandler();
     }
 
-    if (!m_exceptionChecks.empty())
+    if (!m_exceptionChecks.empty()) {
         m_exceptionChecks.link(this);
 
-    // lookupExceptionHandler is passed one argument, the exec (the CallFrame*).
-    move(GPRInfo::callFrameRegister, GPRInfo::argumentGPR0);
+        copyCalleeSavesToVMEntryFrameCalleeSavesBuffer();
 
-    if (doLookup.isSet())
-        doLookup.link(this);
+        // lookupExceptionHandler is passed two arguments, the VM and the exec (the CallFrame*).
+        move(TrustedImmPtr(vm()), GPRInfo::argumentGPR0);
+        move(GPRInfo::callFrameRegister, GPRInfo::argumentGPR1);
 
 #if CPU(X86)
-    // FIXME: should use the call abstraction, but this is currently in the SpeculativeJIT layer!
-    poke(GPRInfo::argumentGPR0);
+        // FIXME: should use the call abstraction, but this is currently in the SpeculativeJIT layer!
+        poke(GPRInfo::argumentGPR0);
+        poke(GPRInfo::argumentGPR1, 1);
 #endif
-    m_calls.append(CallLinkRecord(call(), lookupExceptionHandler));
-    jumpToExceptionHandler();
+        m_calls.append(CallLinkRecord(call(), lookupExceptionHandler));
+
+        jumpToExceptionHandler();
+    }
 }
 
 void JITCompiler::link(LinkBuffer& linkBuffer)
@@ -148,15 +182,18 @@ void JITCompiler::link(LinkBuffer& linkBuffer)
     m_jitCode->common.frameRegisterCount = m_graph.frameRegisterCount();
     m_jitCode->common.requiredRegisterCountForExit = m_graph.requiredRegisterCountForExit();
 
-    if (!m_graph.m_inlineCallFrames->isEmpty())
-        m_jitCode->common.inlineCallFrames = m_graph.m_inlineCallFrames.release();
+    if (!m_graph.m_plan.inlineCallFrames->isEmpty())
+        m_jitCode->common.inlineCallFrames = m_graph.m_plan.inlineCallFrames;
+    
+#if USE(JSVALUE32_64)
+    m_jitCode->common.doubleConstants = WTFMove(m_graph.m_doubleConstants);
+#endif
     
-    m_jitCode->common.machineCaptureStart = m_graph.m_machineCaptureStart;
-    m_jitCode->common.slowArguments = std::move(m_graph.m_slowArguments);
+    m_graph.registerFrozenValues();
 
     BitVector usedJumpTables;
-    for (unsigned i = m_graph.m_switchData.size(); i--;) {
-        SwitchData& data = m_graph.m_switchData[i];
+    for (Bag<SwitchData>::iterator iter = m_graph.m_switchData.begin(); !!iter; ++iter) {
+        SwitchData& data = **iter;
         if (!data.didUseJumpTable)
             continue;
         
@@ -167,14 +204,14 @@ void JITCompiler::link(LinkBuffer& linkBuffer)
         
         usedJumpTables.set(data.switchTableIndex);
         SimpleJumpTable& table = m_codeBlock->switchJumpTable(data.switchTableIndex);
-        table.ctiDefault = linkBuffer.locationOf(m_blockHeads[data.fallThrough->index]);
+        table.ctiDefault = linkBuffer.locationOf(m_blockHeads[data.fallThrough.block->index]);
         table.ctiOffsets.grow(table.branchOffsets.size());
         for (unsigned j = table.ctiOffsets.size(); j--;)
             table.ctiOffsets[j] = table.ctiDefault;
         for (unsigned j = data.cases.size(); j--;) {
             SwitchCase& myCase = data.cases[j];
-            table.ctiOffsets[myCase.value.switchLookupValue() - table.min] =
-                linkBuffer.locationOf(m_blockHeads[myCase.target->index]);
+            table.ctiOffsets[myCase.value.switchLookupValue(data.kind) - table.min] =
+                linkBuffer.locationOf(m_blockHeads[myCase.target.block->index]);
         }
     }
     
@@ -188,8 +225,8 @@ void JITCompiler::link(LinkBuffer& linkBuffer)
     // NOTE: we cannot clear string switch tables because (1) we're running concurrently
     // and we cannot deref StringImpl's and (2) it would be weird to deref those
     // StringImpl's since we refer to them.
-    for (unsigned i = m_graph.m_switchData.size(); i--;) {
-        SwitchData& data = m_graph.m_switchData[i];
+    for (Bag<SwitchData>::iterator switchDataIter = m_graph.m_switchData.begin(); !!switchDataIter; ++switchDataIter) {
+        SwitchData& data = **switchDataIter;
         if (!data.didUseJumpTable)
             continue;
         
@@ -197,7 +234,7 @@ void JITCompiler::link(LinkBuffer& linkBuffer)
             continue;
         
         StringJumpTable& table = m_codeBlock->stringSwitchJumpTable(data.switchTableIndex);
-        table.ctiDefault = linkBuffer.locationOf(m_blockHeads[data.fallThrough->index]);
+        table.ctiDefault = linkBuffer.locationOf(m_blockHeads[data.fallThrough.block->index]);
         StringJumpTable::StringOffsetTable::iterator iter;
         StringJumpTable::StringOffsetTable::iterator end = table.offsetTable.end();
         for (iter = table.offsetTable.begin(); iter != end; ++iter)
@@ -206,7 +243,7 @@ void JITCompiler::link(LinkBuffer& linkBuffer)
             SwitchCase& myCase = data.cases[j];
             iter = table.offsetTable.find(myCase.value.stringImpl());
             RELEASE_ASSERT(iter != end);
-            iter->value.ctiOffset = linkBuffer.locationOf(m_blockHeads[myCase.target->index]);
+            iter->value.ctiOffset = linkBuffer.locationOf(m_blockHeads[myCase.target.block->index]);
         }
     }
 
@@ -221,24 +258,46 @@ void JITCompiler::link(LinkBuffer& linkBuffer)
 
     for (unsigned i = 0; i < m_ins.size(); ++i) {
         StructureStubInfo& info = *m_ins[i].m_stubInfo;
-        CodeLocationCall callReturnLocation = linkBuffer.locationOf(m_ins[i].m_slowPathGenerator->call());
-        info.patch.deltaCallToDone = differenceBetweenCodePtr(callReturnLocation, linkBuffer.locationOf(m_ins[i].m_done));
-        info.patch.deltaCallToJump = differenceBetweenCodePtr(callReturnLocation, linkBuffer.locationOf(m_ins[i].m_jump));
-        info.callReturnLocation = callReturnLocation;
-        info.patch.deltaCallToSlowCase = differenceBetweenCodePtr(callReturnLocation, linkBuffer.locationOf(m_ins[i].m_slowPathGenerator->label()));
+
+        CodeLocationLabel start = linkBuffer.locationOf(m_ins[i].m_jump);
+        info.patch.start = start;
+
+        ptrdiff_t inlineSize = MacroAssembler::differenceBetweenCodePtr(
+            start, linkBuffer.locationOf(m_ins[i].m_done));
+        RELEASE_ASSERT(inlineSize >= 0);
+        info.patch.inlineSize = inlineSize;
+
+        info.patch.deltaFromStartToSlowPathCallLocation = MacroAssembler::differenceBetweenCodePtr(
+            start, linkBuffer.locationOf(m_ins[i].m_slowPathGenerator->call()));
+
+        info.patch.deltaFromStartToSlowPathStart = MacroAssembler::differenceBetweenCodePtr(
+            start, linkBuffer.locationOf(m_ins[i].m_slowPathGenerator->label()));
+    }
+    
+    for (auto& record : m_jsCalls) {
+        CallLinkInfo& info = *record.info;
+        linkBuffer.link(record.slowCall, FunctionPtr(m_vm->getCTIStub(linkCallThunkGenerator).code().executableAddress()));
+        info.setCallLocations(
+            CodeLocationLabel(linkBuffer.locationOfNearCall(record.slowCall)),
+            CodeLocationLabel(linkBuffer.locationOf(record.targetToCheck)),
+            linkBuffer.locationOfNearCall(record.fastCall));
     }
     
-    m_codeBlock->setNumberOfCallLinkInfos(m_jsCalls.size());
-    for (unsigned i = 0; i < m_jsCalls.size(); ++i) {
-        CallLinkInfo& info = m_codeBlock->callLinkInfo(i);
-        info.callType = m_jsCalls[i].m_callType;
-        info.isDFG = true;
-        info.codeOrigin = m_jsCalls[i].m_codeOrigin;
-        linkBuffer.link(m_jsCalls[i].m_slowCall, FunctionPtr((m_vm->getCTIStub(info.callType == CallLinkInfo::Construct ? linkConstructThunkGenerator : linkCallThunkGenerator)).code().executableAddress()));
-        info.callReturnLocation = linkBuffer.locationOfNearCall(m_jsCalls[i].m_slowCall);
-        info.hotPathBegin = linkBuffer.locationOf(m_jsCalls[i].m_targetToCheck);
-        info.hotPathOther = linkBuffer.locationOfNearCall(m_jsCalls[i].m_fastCall);
-        info.calleeGPR = static_cast<unsigned>(m_jsCalls[i].m_callee);
+    for (JSDirectCallRecord& record : m_jsDirectCalls) {
+        CallLinkInfo& info = *record.info;
+        linkBuffer.link(record.call, linkBuffer.locationOf(record.slowPath));
+        info.setCallLocations(
+            CodeLocationLabel(),
+            linkBuffer.locationOf(record.slowPath),
+            linkBuffer.locationOfNearCall(record.call));
+    }
+    
+    for (JSDirectTailCallRecord& record : m_jsDirectTailCalls) {
+        CallLinkInfo& info = *record.info;
+        info.setCallLocations(
+            linkBuffer.locationOf(record.patchableJump),
+            linkBuffer.locationOf(record.slowPath),
+            linkBuffer.locationOfNearCall(record.call));
     }
     
     MacroAssemblerCodeRef osrExitThunk = vm()->getCTIStub(osrExitGenerationThunkGenerator);
@@ -266,23 +325,65 @@ void JITCompiler::link(LinkBuffer& linkBuffer)
         }
     } else
         ASSERT(!m_exitSiteLabels.size());
-    
+
     m_jitCode->common.compilation = m_graph.compilation();
     
+    // Link new DFG exception handlers and remove baseline JIT handlers.
+    m_codeBlock->clearExceptionHandlers();
+    for (unsigned  i = 0; i < m_exceptionHandlerOSRExitCallSites.size(); i++) {
+        OSRExitCompilationInfo& info = m_exceptionHandlerOSRExitCallSites[i].exitInfo;
+        if (info.m_replacementDestination.isSet()) {
+            // If this is is *not* set, it means that we already jumped to the OSR exit in pure generated control flow.
+            // i.e, we explicitly emitted an exceptionCheck that we know will be caught in this machine frame.
+            // If this *is set*, it means we will be landing at this code location from genericUnwind from an
+            // exception thrown in a child call frame.
+            CodeLocationLabel catchLabel = linkBuffer.locationOf(info.m_replacementDestination);
+            HandlerInfo newExceptionHandler = m_exceptionHandlerOSRExitCallSites[i].baselineExceptionHandler;
+            CallSiteIndex callSite = m_exceptionHandlerOSRExitCallSites[i].callSiteIndex;
+            newExceptionHandler.start = callSite.bits();
+            newExceptionHandler.end = callSite.bits() + 1;
+            newExceptionHandler.nativeCode = catchLabel;
+            m_codeBlock->appendExceptionHandler(newExceptionHandler);
+        }
+    }
+
+    if (m_pcToCodeOriginMapBuilder.didBuildMapping())
+        m_codeBlock->setPCToCodeOriginMap(std::make_unique<PCToCodeOriginMap>(WTFMove(m_pcToCodeOriginMapBuilder), linkBuffer));
 }
 
 void JITCompiler::compile()
 {
-    SamplingRegion samplingRegion("DFG Backend");
-
     setStartOfCode();
     compileEntry();
-    m_speculative = adoptPtr(new SpeculativeJIT(*this));
+    m_speculative = std::make_unique<SpeculativeJIT>(*this);
+
+    // Plant a check that sufficient space is available in the JSStack.
+    addPtr(TrustedImm32(virtualRegisterForLocal(m_graph.requiredRegisterCountForExecutionAndExit() - 1).offset() * sizeof(Register)), GPRInfo::callFrameRegister, GPRInfo::regT1);
+    Jump stackOverflow = branchPtr(Above, AbsoluteAddress(m_vm->addressOfSoftStackLimit()), GPRInfo::regT1);
+
+    addPtr(TrustedImm32(m_graph.stackPointerOffset() * sizeof(Register)), GPRInfo::callFrameRegister, stackPointerRegister);
+    checkStackPointerAlignment();
+    compileSetupRegistersForEntry();
+    compileEntryExecutionFlag();
     compileBody();
     setEndOfMainPath();
 
+    // === Footer code generation ===
+    //
+    // Generate the stack overflow handling; if the stack check in the entry head fails,
+    // we need to call out to a helper function to throw the StackOverflowError.
+    stackOverflow.link(this);
+
+    emitStoreCodeOrigin(CodeOrigin(0));
+
+    if (maxFrameExtentForSlowPathCall)
+        addPtr(TrustedImm32(-maxFrameExtentForSlowPathCall), stackPointerRegister);
+
+    m_speculative->callOperationWithCallFrameRollbackOnException(operationThrowStackOverflowError, m_codeBlock);
+
     // Generate slow path code.
-    m_speculative->runSlowPathGenerators();
+    m_speculative->runSlowPathGenerators(m_pcToCodeOriginMapBuilder);
+    m_pcToCodeOriginMapBuilder.appendItem(labelIgnoringWatchpoints(), PCToCodeOriginMapBuilder::defaultCodeOrigin());
     
     compileExceptionHandlers();
     linkOSRExits();
@@ -290,32 +391,27 @@ void JITCompiler::compile()
     // Create OSR entry trampolines if necessary.
     m_speculative->createOSREntries();
     setEndOfCode();
-}
 
-void JITCompiler::link()
-{
-    OwnPtr<LinkBuffer> linkBuffer = adoptPtr(new LinkBuffer(*m_vm, this, m_codeBlock, JITCompilationCanFail));
+    auto linkBuffer = std::make_unique<LinkBuffer>(*m_vm, *this, m_codeBlock, JITCompilationCanFail);
     if (linkBuffer->didFailToAllocate()) {
-        m_graph.m_plan.finalizer = adoptPtr(new FailedFinalizer(m_graph.m_plan));
+        m_graph.m_plan.finalizer = std::make_unique<FailedFinalizer>(m_graph.m_plan);
         return;
     }
     
     link(*linkBuffer);
     m_speculative->linkOSREntries(*linkBuffer);
-    
+
     m_jitCode->shrinkToFit();
     codeBlock()->shrinkToFit(CodeBlock::LateShrink);
 
     disassemble(*linkBuffer);
     
-    m_graph.m_plan.finalizer = adoptPtr(new JITFinalizer(
-        m_graph.m_plan, m_jitCode.release(), linkBuffer.release()));
+    m_graph.m_plan.finalizer = std::make_unique<JITFinalizer>(
+        m_graph.m_plan, m_jitCode.releaseNonNull(), WTFMove(linkBuffer));
 }
 
 void JITCompiler::compileFunction()
 {
-    SamplingRegion samplingRegion("DFG Backend");
-    
     setStartOfCode();
     compileEntry();
 
@@ -325,30 +421,36 @@ void JITCompiler::compileFunction()
     // so enter after this.
     Label fromArityCheck(this);
     // Plant a check that sufficient space is available in the JSStack.
-    addPtr(TrustedImm32(virtualRegisterForLocal(m_graph.requiredRegisterCountForExecutionAndExit()).offset() * sizeof(Register)), GPRInfo::callFrameRegister, GPRInfo::regT1);
-    Jump stackCheck = branchPtr(Above, AbsoluteAddress(m_vm->addressOfJSStackLimit()), GPRInfo::regT1);
-    // Return here after stack check.
-    Label fromStackCheck = label();
+    addPtr(TrustedImm32(virtualRegisterForLocal(m_graph.requiredRegisterCountForExecutionAndExit() - 1).offset() * sizeof(Register)), GPRInfo::callFrameRegister, GPRInfo::regT1);
+    Jump stackOverflow = branchPtr(Above, AbsoluteAddress(m_vm->addressOfSoftStackLimit()), GPRInfo::regT1);
+
+    // Move the stack pointer down to accommodate locals
+    addPtr(TrustedImm32(m_graph.stackPointerOffset() * sizeof(Register)), GPRInfo::callFrameRegister, stackPointerRegister);
+    checkStackPointerAlignment();
 
+    compileSetupRegistersForEntry();
+    compileEntryExecutionFlag();
 
     // === Function body code generation ===
-    m_speculative = adoptPtr(new SpeculativeJIT(*this));
+    m_speculative = std::make_unique<SpeculativeJIT>(*this);
     compileBody();
     setEndOfMainPath();
 
     // === Function footer code generation ===
     //
-    // Generate code to perform the slow stack check (if the fast one in
+    // Generate code to perform the stack overflow handling (if the stack check in
     // the function header fails), and generate the entry point with arity check.
     //
-    // Generate the stack check; if the fast check in the function head fails,
-    // we need to call out to a helper function to check whether more space is available.
-    // FIXME: change this from a cti call to a DFG style operation (normal C calling conventions).
-    stackCheck.link(this);
+    // Generate the stack overflow handling; if the stack check in the function head fails,
+    // we need to call out to a helper function to throw the StackOverflowError.
+    stackOverflow.link(this);
 
     emitStoreCodeOrigin(CodeOrigin(0));
-    m_speculative->callOperationWithCallFrameRollbackOnException(operationStackCheck, m_codeBlock);
-    jump(fromStackCheck);
+
+    if (maxFrameExtentForSlowPathCall)
+        addPtr(TrustedImm32(-maxFrameExtentForSlowPathCall), stackPointerRegister);
+
+    m_speculative->callOperationWithCallFrameRollbackOnException(operationThrowStackOverflowError, m_codeBlock);
     
     // The fast entry point into a function does not check the correct number of arguments
     // have been passed to the call (we only use the fast entry point where we can statically
@@ -358,17 +460,23 @@ void JITCompiler::compileFunction()
     m_arityCheck = label();
     compileEntry();
 
-    load32(AssemblyHelpers::payloadFor((VirtualRegister)JSStack::ArgumentCount), GPRInfo::regT1);
+    load32(AssemblyHelpers::payloadFor((VirtualRegister)CallFrameSlot::argumentCount), GPRInfo::regT1);
     branch32(AboveOrEqual, GPRInfo::regT1, TrustedImm32(m_codeBlock->numParameters())).linkTo(fromArityCheck, this);
     emitStoreCodeOrigin(CodeOrigin(0));
+    if (maxFrameExtentForSlowPathCall)
+        addPtr(TrustedImm32(-maxFrameExtentForSlowPathCall), stackPointerRegister);
     m_speculative->callOperationWithCallFrameRollbackOnException(m_codeBlock->m_isConstructor ? operationConstructArityCheck : operationCallArityCheck, GPRInfo::regT0);
-    branchTest32(Zero, GPRInfo::regT0).linkTo(fromArityCheck, this);
+    if (maxFrameExtentForSlowPathCall)
+        addPtr(TrustedImm32(maxFrameExtentForSlowPathCall), stackPointerRegister);
+    branchTest32(Zero, GPRInfo::returnValueGPR).linkTo(fromArityCheck, this);
     emitStoreCodeOrigin(CodeOrigin(0));
+    move(GPRInfo::returnValueGPR, GPRInfo::argumentGPR0);
     m_callArityFixup = call();
     jump(fromArityCheck);
     
     // Generate slow path code.
-    m_speculative->runSlowPathGenerators();
+    m_speculative->runSlowPathGenerators(m_pcToCodeOriginMapBuilder);
+    m_pcToCodeOriginMapBuilder.appendItem(labelIgnoringWatchpoints(), PCToCodeOriginMapBuilder::defaultCodeOrigin());
     
     compileExceptionHandlers();
     linkOSRExits();
@@ -376,14 +484,11 @@ void JITCompiler::compileFunction()
     // Create OSR entry trampolines if necessary.
     m_speculative->createOSREntries();
     setEndOfCode();
-}
 
-void JITCompiler::linkFunction()
-{
     // === Link ===
-    OwnPtr<LinkBuffer> linkBuffer = adoptPtr(new LinkBuffer(*m_vm, this, m_codeBlock, JITCompilationCanFail));
+    auto linkBuffer = std::make_unique<LinkBuffer>(*m_vm, *this, m_codeBlock, JITCompilationCanFail);
     if (linkBuffer->didFailToAllocate()) {
-        m_graph.m_plan.finalizer = adoptPtr(new FailedFinalizer(m_graph.m_plan));
+        m_graph.m_plan.finalizer = std::make_unique<FailedFinalizer>(m_graph.m_plan);
         return;
     }
     link(*linkBuffer);
@@ -392,25 +497,165 @@ void JITCompiler::linkFunction()
     m_jitCode->shrinkToFit();
     codeBlock()->shrinkToFit(CodeBlock::LateShrink);
     
-    linkBuffer->link(m_callArityFixup, FunctionPtr((m_vm->getCTIStub(arityFixup)).code().executableAddress()));
+    linkBuffer->link(m_callArityFixup, FunctionPtr((m_vm->getCTIStub(arityFixupGenerator)).code().executableAddress()));
     
     disassemble(*linkBuffer);
 
     MacroAssemblerCodePtr withArityCheck = linkBuffer->locationOf(m_arityCheck);
 
-    m_graph.m_plan.finalizer = adoptPtr(new JITFinalizer(
-        m_graph.m_plan, m_jitCode.release(), linkBuffer.release(), withArityCheck));
+    m_graph.m_plan.finalizer = std::make_unique<JITFinalizer>(
+        m_graph.m_plan, m_jitCode.releaseNonNull(), WTFMove(linkBuffer), withArityCheck);
 }
 
 void JITCompiler::disassemble(LinkBuffer& linkBuffer)
 {
-    if (shouldShowDisassembly())
+    if (shouldDumpDisassembly()) {
         m_disassembler->dump(linkBuffer);
+        linkBuffer.didAlreadyDisassemble();
+    }
     
     if (m_graph.m_plan.compilation)
         m_disassembler->reportToProfiler(m_graph.m_plan.compilation.get(), linkBuffer);
 }
 
+#if USE(JSVALUE32_64)
+void* JITCompiler::addressOfDoubleConstant(Node* node)
+{
+    double value = node->asNumber();
+    int64_t valueBits = bitwise_cast<int64_t>(value);
+    auto it = m_graph.m_doubleConstantsMap.find(valueBits);
+    if (it != m_graph.m_doubleConstantsMap.end())
+        return it->second;
+
+    if (!m_graph.m_doubleConstants)
+        m_graph.m_doubleConstants = std::make_unique<Bag<double>>();
+
+    double* addressInConstantPool = m_graph.m_doubleConstants->add();
+    *addressInConstantPool = value;
+    m_graph.m_doubleConstantsMap[valueBits] = addressInConstantPool;
+    return addressInConstantPool;
+}
+#endif
+
+void JITCompiler::noticeOSREntry(BasicBlock& basicBlock, JITCompiler::Label blockHead, LinkBuffer& linkBuffer)
+{
+    // OSR entry is not allowed into blocks deemed unreachable by control flow analysis.
+    if (!basicBlock.intersectionOfCFAHasVisited)
+        return;
+        
+    OSREntryData* entry = m_jitCode->appendOSREntryData(basicBlock.bytecodeBegin, linkBuffer.offsetOf(blockHead));
+    
+    entry->m_expectedValues = basicBlock.intersectionOfPastValuesAtHead;
+        
+    // Fix the expected values: in our protocol, a dead variable will have an expected
+    // value of (None, []). But the old JIT may stash some values there. So we really
+    // need (Top, TOP).
+    for (size_t argument = 0; argument < basicBlock.variablesAtHead.numberOfArguments(); ++argument) {
+        Node* node = basicBlock.variablesAtHead.argument(argument);
+        if (!node || !node->shouldGenerate())
+            entry->m_expectedValues.argument(argument).makeHeapTop();
+    }
+    for (size_t local = 0; local < basicBlock.variablesAtHead.numberOfLocals(); ++local) {
+        Node* node = basicBlock.variablesAtHead.local(local);
+        if (!node || !node->shouldGenerate())
+            entry->m_expectedValues.local(local).makeHeapTop();
+        else {
+            VariableAccessData* variable = node->variableAccessData();
+            entry->m_machineStackUsed.set(variable->machineLocal().toLocal());
+                
+            switch (variable->flushFormat()) {
+            case FlushedDouble:
+                entry->m_localsForcedDouble.set(local);
+                break;
+            case FlushedInt52:
+                entry->m_localsForcedAnyInt.set(local);
+                break;
+            default:
+                break;
+            }
+            
+            if (variable->local() != variable->machineLocal()) {
+                entry->m_reshufflings.append(
+                    OSREntryReshuffling(
+                        variable->local().offset(), variable->machineLocal().offset()));
+            }
+        }
+    }
+        
+    entry->m_reshufflings.shrinkToFit();
+}
+
+void JITCompiler::appendExceptionHandlingOSRExit(ExitKind kind, unsigned eventStreamIndex, CodeOrigin opCatchOrigin, HandlerInfo* exceptionHandler, CallSiteIndex callSite, MacroAssembler::JumpList jumpsToFail)
+{
+    OSRExit exit(kind, JSValueRegs(), MethodOfGettingAValueProfile(), m_speculative.get(), eventStreamIndex);
+    exit.m_codeOrigin = opCatchOrigin;
+    exit.m_exceptionHandlerCallSiteIndex = callSite;
+    OSRExitCompilationInfo& exitInfo = appendExitInfo(jumpsToFail);
+    jitCode()->appendOSRExit(exit);
+    m_exceptionHandlerOSRExitCallSites.append(ExceptionHandlingOSRExitInfo { exitInfo, *exceptionHandler, callSite });
+}
+
+void JITCompiler::exceptionCheck()
+{
+    // It's important that we use origin.forExit here. Consider if we hoist string
+    // addition outside a loop, and that we exit at the point of that concatenation
+    // from an out of memory exception.
+    // If the original loop had a try/catch around string concatenation, if we "catch"
+    // that exception inside the loop, then the loops induction variable will be undefined 
+    // in the OSR exit value recovery. It's more defensible for the string concatenation, 
+    // then, to not be caught by the for loops' try/catch.
+    // Here is the program I'm speaking about:
+    //
+    // >>>> lets presume "c = a + b" gets hoisted here.
+    // for (var i = 0; i < length; i++) {
+    //     try {
+    //         c = a + b
+    //     } catch(e) { 
+    //         If we threw an out of memory error, and we cought the exception
+    //         right here, then "i" would almost certainly be undefined, which
+    //         would make no sense.
+    //         ... 
+    //     }
+    // }
+    CodeOrigin opCatchOrigin;
+    HandlerInfo* exceptionHandler;
+    bool willCatchException = m_graph.willCatchExceptionInMachineFrame(m_speculative->m_currentNode->origin.forExit, opCatchOrigin, exceptionHandler); 
+    if (willCatchException) {
+        unsigned streamIndex = m_speculative->m_outOfLineStreamIndex ? *m_speculative->m_outOfLineStreamIndex : m_speculative->m_stream->size();
+        MacroAssembler::Jump hadException = emitNonPatchableExceptionCheck();
+        // We assume here that this is called after callOpeartion()/appendCall() is called.
+        appendExceptionHandlingOSRExit(ExceptionCheck, streamIndex, opCatchOrigin, exceptionHandler, m_jitCode->common.lastCallSite(), hadException);
+    } else
+        m_exceptionChecks.append(emitExceptionCheck());
+}
+
+CallSiteIndex JITCompiler::recordCallSiteAndGenerateExceptionHandlingOSRExitIfNeeded(const CodeOrigin& callSiteCodeOrigin, unsigned eventStreamIndex)
+{
+    CodeOrigin opCatchOrigin;
+    HandlerInfo* exceptionHandler;
+    bool willCatchException = m_graph.willCatchExceptionInMachineFrame(callSiteCodeOrigin, opCatchOrigin, exceptionHandler);
+    CallSiteIndex callSite = addCallSite(callSiteCodeOrigin);
+    if (willCatchException)
+        appendExceptionHandlingOSRExit(GenericUnwind, eventStreamIndex, opCatchOrigin, exceptionHandler, callSite);
+    return callSite;
+}
+
+void JITCompiler::setEndOfMainPath()
+{
+    m_pcToCodeOriginMapBuilder.appendItem(labelIgnoringWatchpoints(), m_speculative->m_origin.semantic);
+    if (LIKELY(!m_disassembler))
+        return;
+    m_disassembler->setEndOfMainPath(labelIgnoringWatchpoints());
+}
+
+void JITCompiler::setEndOfCode()
+{
+    m_pcToCodeOriginMapBuilder.appendItem(labelIgnoringWatchpoints(), PCToCodeOriginMapBuilder::defaultCodeOrigin());
+    if (LIKELY(!m_disassembler))
+        return;
+    m_disassembler->setEndOfCode(labelIgnoringWatchpoints());
+}
+
 } } // namespace JSC::DFG
 
 #endif // ENABLE(DFG_JIT)