Source/JavaScriptCore/dfg/DFGJITCompiler.h - WebKit - Git at Google

 /*
  * Copyright (C) 2011-2018 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #pragma once

 #if ENABLE(DFG_JIT)

 #include "CCallHelpers.h"
 #include "CodeBlock.h"
 #include "DFGDisassembler.h"
 #include "DFGGraph.h"
 #include "DFGInlineCacheWrapper.h"
 #include "DFGJITCode.h"
 #include "DFGOSRExitCompilationInfo.h"
 #include "GPRInfo.h"
 #include "HandlerInfo.h"
 #include "JITCode.h"
 #include "JITInlineCacheGenerator.h"
 #include "LinkBuffer.h"
 #include "MacroAssembler.h"
 #include "PCToCodeOriginMap.h"

 namespace JSC {

 class AbstractSamplingCounter;
 class CodeBlock;
 class VM;

 namespace DFG {

 class JITCodeGenerator;
 class NodeToRegisterMap;
 class OSRExitJumpPlaceholder;
 class SlowPathGenerator;
 class SpeculativeJIT;
 class SpeculationRecovery;

 struct EntryLocation;
 struct OSRExit;

 // === CallLinkRecord ===
 //
 // A record of a call out from JIT code that needs linking to a helper function.
 // Every CallLinkRecord contains a reference to the call instruction & the function
 // that it needs to be linked to.
 struct CallLinkRecord {
     CallLinkRecord(MacroAssembler::Call call, FunctionPtr<OperationPtrTag> function)
         : m_call(call)
         , m_function(function)
     {
     }

     MacroAssembler::Call m_call;
     FunctionPtr<OperationPtrTag> m_function;
 };

 struct InRecord {
     InRecord(
         MacroAssembler::PatchableJump jump, MacroAssembler::Label done,
         SlowPathGenerator* slowPathGenerator, StructureStubInfo* stubInfo)
         : m_jump(jump)
         , m_done(done)
         , m_slowPathGenerator(slowPathGenerator)
         , m_stubInfo(stubInfo)
     {
     }

     MacroAssembler::PatchableJump m_jump;
     MacroAssembler::Label m_done;
     SlowPathGenerator* m_slowPathGenerator;
     StructureStubInfo* m_stubInfo;
 };

 // === JITCompiler ===
 //
 // DFG::JITCompiler is responsible for generating JIT code from the dataflow graph.
 // It does so by delegating to the speculative & non-speculative JITs, which
 // generate to a MacroAssembler (which the JITCompiler owns through an inheritance
 // relationship). The JITCompiler holds references to information required during
 // compilation, and also records information used in linking (e.g. a list of all
 // call to be linked).
 class JITCompiler : public CCallHelpers {
 public:
     JITCompiler(Graph& dfg);
     ~JITCompiler();

     void compile();
     void compileFunction();

     // Accessors for properties.
     Graph& graph() { return m_graph; }

     // Methods to set labels for the disassembler.
     void setStartOfCode()
     {
         m_pcToCodeOriginMapBuilder.appendItem(labelIgnoringWatchpoints(), CodeOrigin(0, nullptr));
         if (LIKELY(!m_disassembler))
             return;
         m_disassembler->setStartOfCode(labelIgnoringWatchpoints());
     }

     void setForBlockIndex(BlockIndex blockIndex)
     {
         if (LIKELY(!m_disassembler))
             return;
         m_disassembler->setForBlockIndex(blockIndex, labelIgnoringWatchpoints());
     }

     void setForNode(Node* node)
     {
         if (LIKELY(!m_disassembler))
             return;
         m_disassembler->setForNode(node, labelIgnoringWatchpoints());
     }

     void setEndOfMainPath();
     void setEndOfCode();

     CallSiteIndex addCallSite(CodeOrigin codeOrigin)
     {
         return m_jitCode->common.addCodeOrigin(codeOrigin);
     }

     CallSiteIndex emitStoreCodeOrigin(CodeOrigin codeOrigin)
     {
         CallSiteIndex callSite = addCallSite(codeOrigin);
         emitStoreCallSiteIndex(callSite);
         return callSite;
     }

     void emitStoreCallSiteIndex(CallSiteIndex callSite)
     {
         store32(TrustedImm32(callSite.bits()), tagFor(static_cast<VirtualRegister>(CallFrameSlot::argumentCount)));
     }

     // Add a call out from JIT code, without an exception check.
     Call appendCall(const FunctionPtr<CFunctionPtrTag> function)
     {
         Call functionCall = call(OperationPtrTag);
         m_calls.append(CallLinkRecord(functionCall, function.retagged<OperationPtrTag>()));
         return functionCall;
     }

     void exceptionCheck();

     void exceptionCheckWithCallFrameRollback()
     {
         m_exceptionChecksWithCallFrameRollback.append(emitExceptionCheck(*vm()));
     }

     // Add a call out from JIT code, with a fast exception check that tests if the return value is zero.
     void fastExceptionCheck()
     {
         callExceptionFuzz(*vm());
         m_exceptionChecks.append(branchTestPtr(Zero, GPRInfo::returnValueGPR));
     }

     OSRExitCompilationInfo& appendExitInfo(MacroAssembler::JumpList jumpsToFail = MacroAssembler::JumpList())
     {
         OSRExitCompilationInfo info;
         info.m_failureJumps = jumpsToFail;
         m_exitCompilationInfo.append(info);
         return m_exitCompilationInfo.last();
     }

 #if USE(JSVALUE32_64)
     void* addressOfDoubleConstant(Node*);
 #endif

     void addGetById(const JITGetByIdGenerator& gen, SlowPathGenerator* slowPath)
     {
         m_getByIds.append(InlineCacheWrapper<JITGetByIdGenerator>(gen, slowPath));
     }

     void addGetByIdWithThis(const JITGetByIdWithThisGenerator& gen, SlowPathGenerator* slowPath)
     {
         m_getByIdsWithThis.append(InlineCacheWrapper<JITGetByIdWithThisGenerator>(gen, slowPath));
     }

     void addPutById(const JITPutByIdGenerator& gen, SlowPathGenerator* slowPath)
     {
         m_putByIds.append(InlineCacheWrapper<JITPutByIdGenerator>(gen, slowPath));
     }

     void addIn(const InRecord& record)
     {
         m_ins.append(record);
     }

     void addJSCall(Call fastCall, Call slowCall, DataLabelPtr targetToCheck, CallLinkInfo* info)
     {
         m_jsCalls.append(JSCallRecord(fastCall, slowCall, targetToCheck, info));
     }

     void addJSDirectCall(Call call, Label slowPath, CallLinkInfo* info)
     {
         m_jsDirectCalls.append(JSDirectCallRecord(call, slowPath, info));
     }

     void addJSDirectTailCall(PatchableJump patchableJump, Call call, Label slowPath, CallLinkInfo* info)
     {
         m_jsDirectTailCalls.append(JSDirectTailCallRecord(patchableJump, call, slowPath, info));
     }

     void addWeakReference(JSCell* target)
     {
         m_graph.m_plan.weakReferences.addLazily(target);
     }

     void addWeakReferences(const StructureSet& structureSet)
     {
         for (unsigned i = structureSet.size(); i--;)
             addWeakReference(structureSet[i]);
     }

     template<typename T>
     Jump branchWeakPtr(RelationalCondition cond, T left, JSCell* weakPtr)
     {
         Jump result = branchPtr(cond, left, TrustedImmPtr(weakPtr));
         addWeakReference(weakPtr);
         return result;
     }

     template<typename T>
     Jump branchWeakStructure(RelationalCondition cond, T left, RegisteredStructure weakStructure)
     {
         Structure* structure = weakStructure.get();
 #if USE(JSVALUE64)
         Jump result = branch32(cond, left, TrustedImm32(structure->id()));
         return result;
 #else
         return branchPtr(cond, left, TrustedImmPtr(structure));
 #endif
     }

     void noticeOSREntry(BasicBlock&, JITCompiler::Label blockHead, LinkBuffer&);
     void noticeCatchEntrypoint(BasicBlock&, JITCompiler::Label blockHead, LinkBuffer&, Vector<FlushFormat>&& argumentFormats);

     RefPtr<JITCode> jitCode() { return m_jitCode; }

     Vector<Label>& blockHeads() { return m_blockHeads; }

     CallSiteIndex recordCallSiteAndGenerateExceptionHandlingOSRExitIfNeeded(const CodeOrigin&, unsigned eventStreamIndex);

     PCToCodeOriginMapBuilder& pcToCodeOriginMapBuilder() { return m_pcToCodeOriginMapBuilder; }

     VM* vm() { return &m_graph.m_vm; }

 private:
     friend class OSRExitJumpPlaceholder;

     // Internal implementation to compile.
     void compileEntry();
     void compileSetupRegistersForEntry();
     void compileEntryExecutionFlag();
     void compileBody();
     void link(LinkBuffer&);

     void exitSpeculativeWithOSR(const OSRExit&, SpeculationRecovery*);
     void compileExceptionHandlers();
     void linkOSRExits();
     void disassemble(LinkBuffer&);

     void appendExceptionHandlingOSRExit(ExitKind, unsigned eventStreamIndex, CodeOrigin, HandlerInfo* exceptionHandler, CallSiteIndex, MacroAssembler::JumpList jumpsToFail = MacroAssembler::JumpList());

     void makeCatchOSREntryBuffer();

     // The dataflow graph currently being generated.
     Graph& m_graph;

     std::unique_ptr<Disassembler> m_disassembler;

     RefPtr<JITCode> m_jitCode;

     // Vector of calls out from JIT code, including exception handler information.
     // Count of the number of CallRecords with exception handlers.
     Vector<CallLinkRecord> m_calls;
     JumpList m_exceptionChecks;
     JumpList m_exceptionChecksWithCallFrameRollback;

     Vector<Label> m_blockHeads;


     struct JSCallRecord {
         JSCallRecord(Call fastCall, Call slowCall, DataLabelPtr targetToCheck, CallLinkInfo* info)
             : fastCall(fastCall)
             , slowCall(slowCall)
             , targetToCheck(targetToCheck)
             , info(info)
         {
             ASSERT(fastCall.isFlagSet(Call::Near));
             ASSERT(slowCall.isFlagSet(Call::Near));
         }

         Call fastCall;
         Call slowCall;
         DataLabelPtr targetToCheck;
         CallLinkInfo* info;
     };

     struct JSDirectCallRecord {
         JSDirectCallRecord(Call call, Label slowPath, CallLinkInfo* info)
             : call(call)
             , slowPath(slowPath)
             , info(info)
         {
             ASSERT(call.isFlagSet(Call::Near));
         }

         Call call;
         Label slowPath;
         CallLinkInfo* info;
     };

     struct JSDirectTailCallRecord {
         JSDirectTailCallRecord(PatchableJump patchableJump, Call call, Label slowPath, CallLinkInfo* info)
             : patchableJump(patchableJump)
             , call(call)
             , slowPath(slowPath)
             , info(info)
         {
             ASSERT(call.isFlagSet(Call::Near) && call.isFlagSet(Call::Tail));
         }

         PatchableJump patchableJump;
         Call call;
         Label slowPath;
         CallLinkInfo* info;
     };


     Vector<InlineCacheWrapper<JITGetByIdGenerator>, 4> m_getByIds;
     Vector<InlineCacheWrapper<JITGetByIdWithThisGenerator>, 4> m_getByIdsWithThis;
     Vector<InlineCacheWrapper<JITPutByIdGenerator>, 4> m_putByIds;
     Vector<InRecord, 4> m_ins;
     Vector<JSCallRecord, 4> m_jsCalls;
     Vector<JSDirectCallRecord, 4> m_jsDirectCalls;
     Vector<JSDirectTailCallRecord, 4> m_jsDirectTailCalls;
     SegmentedVector<OSRExitCompilationInfo, 4> m_exitCompilationInfo;
     Vector<Vector<Label>> m_exitSiteLabels;

     struct ExceptionHandlingOSRExitInfo {
         OSRExitCompilationInfo& exitInfo;
         HandlerInfo baselineExceptionHandler;
         CallSiteIndex callSiteIndex;
     };
     Vector<ExceptionHandlingOSRExitInfo> m_exceptionHandlerOSRExitCallSites;

     Label m_arityCheck;
     std::unique_ptr<SpeculativeJIT> m_speculative;
     PCToCodeOriginMapBuilder m_pcToCodeOriginMapBuilder;
 };

 } } // namespace JSC::DFG

 #endif
	/*
	* Copyright (C) 2011-2018 Apple Inc. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
	* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
	* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
	* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
	* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
	* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
	* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#pragma once

	#if ENABLE(DFG_JIT)

	#include "CCallHelpers.h"
	#include "CodeBlock.h"
	#include "DFGDisassembler.h"
	#include "DFGGraph.h"
	#include "DFGInlineCacheWrapper.h"
	#include "DFGJITCode.h"
	#include "DFGOSRExitCompilationInfo.h"
	#include "GPRInfo.h"
	#include "HandlerInfo.h"
	#include "JITCode.h"
	#include "JITInlineCacheGenerator.h"
	#include "LinkBuffer.h"
	#include "MacroAssembler.h"
	#include "PCToCodeOriginMap.h"

	namespace JSC {

	class AbstractSamplingCounter;
	class CodeBlock;
	class VM;

	namespace DFG {

	class JITCodeGenerator;
	class NodeToRegisterMap;
	class OSRExitJumpPlaceholder;
	class SlowPathGenerator;
	class SpeculativeJIT;
	class SpeculationRecovery;

	struct EntryLocation;
	struct OSRExit;

	// === CallLinkRecord ===
	//
	// A record of a call out from JIT code that needs linking to a helper function.
	// Every CallLinkRecord contains a reference to the call instruction & the function
	// that it needs to be linked to.
	struct CallLinkRecord {
	CallLinkRecord(MacroAssembler::Call call, FunctionPtr<OperationPtrTag> function)
	: m_call(call)
	, m_function(function)
	{
	}

	MacroAssembler::Call m_call;
	FunctionPtr<OperationPtrTag> m_function;
	};

	struct InRecord {
	InRecord(
	MacroAssembler::PatchableJump jump, MacroAssembler::Label done,
	SlowPathGenerator* slowPathGenerator, StructureStubInfo* stubInfo)
	: m_jump(jump)
	, m_done(done)
	, m_slowPathGenerator(slowPathGenerator)
	, m_stubInfo(stubInfo)
	{
	}

	MacroAssembler::PatchableJump m_jump;
	MacroAssembler::Label m_done;
	SlowPathGenerator* m_slowPathGenerator;
	StructureStubInfo* m_stubInfo;
	};

	// === JITCompiler ===
	//
	// DFG::JITCompiler is responsible for generating JIT code from the dataflow graph.
	// It does so by delegating to the speculative & non-speculative JITs, which
	// generate to a MacroAssembler (which the JITCompiler owns through an inheritance
	// relationship). The JITCompiler holds references to information required during
	// compilation, and also records information used in linking (e.g. a list of all
	// call to be linked).
	class JITCompiler : public CCallHelpers {
	public:
	JITCompiler(Graph& dfg);
	~JITCompiler();

	void compile();
	void compileFunction();

	// Accessors for properties.
	Graph& graph() { return m_graph; }

	// Methods to set labels for the disassembler.
	void setStartOfCode()
	{
	m_pcToCodeOriginMapBuilder.appendItem(labelIgnoringWatchpoints(), CodeOrigin(0, nullptr));
	if (LIKELY(!m_disassembler))
	return;
	m_disassembler->setStartOfCode(labelIgnoringWatchpoints());
	}

	void setForBlockIndex(BlockIndex blockIndex)
	{
	if (LIKELY(!m_disassembler))
	return;
	m_disassembler->setForBlockIndex(blockIndex, labelIgnoringWatchpoints());
	}

	void setForNode(Node* node)
	{
	if (LIKELY(!m_disassembler))
	return;
	m_disassembler->setForNode(node, labelIgnoringWatchpoints());
	}

	void setEndOfMainPath();
	void setEndOfCode();

	CallSiteIndex addCallSite(CodeOrigin codeOrigin)
	{
	return m_jitCode->common.addCodeOrigin(codeOrigin);
	}

	CallSiteIndex emitStoreCodeOrigin(CodeOrigin codeOrigin)
	{
	CallSiteIndex callSite = addCallSite(codeOrigin);
	emitStoreCallSiteIndex(callSite);
	return callSite;
	}

	void emitStoreCallSiteIndex(CallSiteIndex callSite)
	{
	store32(TrustedImm32(callSite.bits()), tagFor(static_cast<VirtualRegister>(CallFrameSlot::argumentCount)));
	}

	// Add a call out from JIT code, without an exception check.
	Call appendCall(const FunctionPtr<CFunctionPtrTag> function)
	{
	Call functionCall = call(OperationPtrTag);
	m_calls.append(CallLinkRecord(functionCall, function.retagged<OperationPtrTag>()));
	return functionCall;
	}

	void exceptionCheck();

	void exceptionCheckWithCallFrameRollback()
	{
	m_exceptionChecksWithCallFrameRollback.append(emitExceptionCheck(*vm()));
	}

	// Add a call out from JIT code, with a fast exception check that tests if the return value is zero.
	void fastExceptionCheck()
	{
	callExceptionFuzz(*vm());
	m_exceptionChecks.append(branchTestPtr(Zero, GPRInfo::returnValueGPR));
	}

	OSRExitCompilationInfo& appendExitInfo(MacroAssembler::JumpList jumpsToFail = MacroAssembler::JumpList())
	{
	OSRExitCompilationInfo info;
	info.m_failureJumps = jumpsToFail;
	m_exitCompilationInfo.append(info);
	return m_exitCompilationInfo.last();
	}

	#if USE(JSVALUE32_64)
	void* addressOfDoubleConstant(Node*);
	#endif

	void addGetById(const JITGetByIdGenerator& gen, SlowPathGenerator* slowPath)
	{
	m_getByIds.append(InlineCacheWrapper<JITGetByIdGenerator>(gen, slowPath));
	}

	void addGetByIdWithThis(const JITGetByIdWithThisGenerator& gen, SlowPathGenerator* slowPath)
	{
	m_getByIdsWithThis.append(InlineCacheWrapper<JITGetByIdWithThisGenerator>(gen, slowPath));
	}

	void addPutById(const JITPutByIdGenerator& gen, SlowPathGenerator* slowPath)
	{
	m_putByIds.append(InlineCacheWrapper<JITPutByIdGenerator>(gen, slowPath));
	}

	void addIn(const InRecord& record)
	{
	m_ins.append(record);
	}

	void addJSCall(Call fastCall, Call slowCall, DataLabelPtr targetToCheck, CallLinkInfo* info)
	{
	m_jsCalls.append(JSCallRecord(fastCall, slowCall, targetToCheck, info));
	}

	void addJSDirectCall(Call call, Label slowPath, CallLinkInfo* info)
	{
	m_jsDirectCalls.append(JSDirectCallRecord(call, slowPath, info));
	}

	void addJSDirectTailCall(PatchableJump patchableJump, Call call, Label slowPath, CallLinkInfo* info)
	{
	m_jsDirectTailCalls.append(JSDirectTailCallRecord(patchableJump, call, slowPath, info));
	}

	void addWeakReference(JSCell* target)
	{
	m_graph.m_plan.weakReferences.addLazily(target);
	}

	void addWeakReferences(const StructureSet& structureSet)
	{
	for (unsigned i = structureSet.size(); i--;)
	addWeakReference(structureSet[i]);
	}

	template<typename T>
	Jump branchWeakPtr(RelationalCondition cond, T left, JSCell* weakPtr)
	{
	Jump result = branchPtr(cond, left, TrustedImmPtr(weakPtr));
	addWeakReference(weakPtr);
	return result;
	}

	template<typename T>
	Jump branchWeakStructure(RelationalCondition cond, T left, RegisteredStructure weakStructure)
	{
	Structure* structure = weakStructure.get();
	#if USE(JSVALUE64)
	Jump result = branch32(cond, left, TrustedImm32(structure->id()));
	return result;
	#else
	return branchPtr(cond, left, TrustedImmPtr(structure));
	#endif
	}

	void noticeOSREntry(BasicBlock&, JITCompiler::Label blockHead, LinkBuffer&);
	void noticeCatchEntrypoint(BasicBlock&, JITCompiler::Label blockHead, LinkBuffer&, Vector<FlushFormat>&& argumentFormats);

	RefPtr<JITCode> jitCode() { return m_jitCode; }

	Vector<Label>& blockHeads() { return m_blockHeads; }

	CallSiteIndex recordCallSiteAndGenerateExceptionHandlingOSRExitIfNeeded(const CodeOrigin&, unsigned eventStreamIndex);

	PCToCodeOriginMapBuilder& pcToCodeOriginMapBuilder() { return m_pcToCodeOriginMapBuilder; }

	VM* vm() { return &m_graph.m_vm; }

	private:
	friend class OSRExitJumpPlaceholder;

	// Internal implementation to compile.
	void compileEntry();
	void compileSetupRegistersForEntry();
	void compileEntryExecutionFlag();
	void compileBody();
	void link(LinkBuffer&);

	void exitSpeculativeWithOSR(const OSRExit&, SpeculationRecovery*);
	void compileExceptionHandlers();
	void linkOSRExits();
	void disassemble(LinkBuffer&);

	void appendExceptionHandlingOSRExit(ExitKind, unsigned eventStreamIndex, CodeOrigin, HandlerInfo* exceptionHandler, CallSiteIndex, MacroAssembler::JumpList jumpsToFail = MacroAssembler::JumpList());

	void makeCatchOSREntryBuffer();

	// The dataflow graph currently being generated.
	Graph& m_graph;

	std::unique_ptr<Disassembler> m_disassembler;

	RefPtr<JITCode> m_jitCode;

	// Vector of calls out from JIT code, including exception handler information.
	// Count of the number of CallRecords with exception handlers.
	Vector<CallLinkRecord> m_calls;
	JumpList m_exceptionChecks;
	JumpList m_exceptionChecksWithCallFrameRollback;

	Vector<Label> m_blockHeads;


	struct JSCallRecord {
	JSCallRecord(Call fastCall, Call slowCall, DataLabelPtr targetToCheck, CallLinkInfo* info)
	: fastCall(fastCall)
	, slowCall(slowCall)
	, targetToCheck(targetToCheck)
	, info(info)
	{
	ASSERT(fastCall.isFlagSet(Call::Near));
	ASSERT(slowCall.isFlagSet(Call::Near));
	}

	Call fastCall;
	Call slowCall;
	DataLabelPtr targetToCheck;
	CallLinkInfo* info;
	};

	struct JSDirectCallRecord {
	JSDirectCallRecord(Call call, Label slowPath, CallLinkInfo* info)
	: call(call)
	, slowPath(slowPath)
	, info(info)
	{
	ASSERT(call.isFlagSet(Call::Near));
	}

	Call call;
	Label slowPath;
	CallLinkInfo* info;
	};

	struct JSDirectTailCallRecord {
	JSDirectTailCallRecord(PatchableJump patchableJump, Call call, Label slowPath, CallLinkInfo* info)
	: patchableJump(patchableJump)
	, call(call)
	, slowPath(slowPath)
	, info(info)
	{
	ASSERT(call.isFlagSet(Call::Near) && call.isFlagSet(Call::Tail));
	}

	PatchableJump patchableJump;
	Call call;
	Label slowPath;
	CallLinkInfo* info;
	};


	Vector<InlineCacheWrapper<JITGetByIdGenerator>, 4> m_getByIds;
	Vector<InlineCacheWrapper<JITGetByIdWithThisGenerator>, 4> m_getByIdsWithThis;
	Vector<InlineCacheWrapper<JITPutByIdGenerator>, 4> m_putByIds;
	Vector<InRecord, 4> m_ins;
	Vector<JSCallRecord, 4> m_jsCalls;
	Vector<JSDirectCallRecord, 4> m_jsDirectCalls;
	Vector<JSDirectTailCallRecord, 4> m_jsDirectTailCalls;
	SegmentedVector<OSRExitCompilationInfo, 4> m_exitCompilationInfo;
	Vector<Vector<Label>> m_exitSiteLabels;

	struct ExceptionHandlingOSRExitInfo {
	OSRExitCompilationInfo& exitInfo;
	HandlerInfo baselineExceptionHandler;
	CallSiteIndex callSiteIndex;
	};
	Vector<ExceptionHandlingOSRExitInfo> m_exceptionHandlerOSRExitCallSites;

	Label m_arityCheck;
	std::unique_ptr<SpeculativeJIT> m_speculative;
	PCToCodeOriginMapBuilder m_pcToCodeOriginMapBuilder;
	};

	} } // namespace JSC::DFG

	#endif