Updated WebKit from /home/shausman/src/webkit/trunk to qtwebkit-4.6-snapshot-15062009 ( 65232bf00dc494ebfd978f998c88f58d18ecce1e )

1 files changed, 999 insertions, 0 deletions

diff --git a/src/3rdparty/webkit/JavaScriptCore/assembler/AbstractMacroAssembler.h b/src/3rdparty/webkit/JavaScriptCore/assembler/AbstractMacroAssembler.h
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+/*
+ * Copyright (C) 2008 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. 
+ */
+
+#ifndef AbstractMacroAssembler_h
+#define AbstractMacroAssembler_h
+
+#include <wtf/Platform.h>
+
+#include <MacroAssemblerCodeRef.h>
+#include <wtf/Noncopyable.h>
+#include <wtf/UnusedParam.h>
+
+#if ENABLE(ASSEMBLER)
+
+// FIXME: keep transitioning this out into MacroAssemblerX86_64.
+#if PLATFORM(X86_64)
+#define REPTACH_OFFSET_CALL_R11 3
+#endif
+
+namespace JSC {
+
+template <class AssemblerType>
+class AbstractMacroAssembler {
+public:
+    typedef MacroAssemblerCodePtr CodePtr;
+    typedef MacroAssemblerCodeRef CodeRef;
+
+    class Jump;
+    class PatchBuffer;
+    class CodeLocationInstruction;
+    class CodeLocationLabel;
+    class CodeLocationJump;
+    class CodeLocationCall;
+    class CodeLocationNearCall;
+    class CodeLocationDataLabel32;
+    class CodeLocationDataLabelPtr;
+    class ProcessorReturnAddress;
+
+    typedef typename AssemblerType::RegisterID RegisterID;
+    typedef typename AssemblerType::FPRegisterID FPRegisterID;
+    typedef typename AssemblerType::JmpSrc JmpSrc;
+    typedef typename AssemblerType::JmpDst JmpDst;
+
+
+    // Section 1: MacroAssembler operand types
+    //
+    // The following types are used as operands to MacroAssembler operations,
+    // describing immediate  and memory operands to the instructions to be planted.
+
+
+    enum Scale {
+        TimesOne,
+        TimesTwo,
+        TimesFour,
+        TimesEight,
+    };
+
+    // Address:
+    //
+    // Describes a simple base-offset address.
+    struct Address {
+        explicit Address(RegisterID base, int32_t offset = 0)
+            : base(base)
+            , offset(offset)
+        {
+        }
+
+        RegisterID base;
+        int32_t offset;
+    };
+
+    // ImplicitAddress:
+    //
+    // This class is used for explicit 'load' and 'store' operations
+    // (as opposed to situations in which a memory operand is provided
+    // to a generic operation, such as an integer arithmetic instruction).
+    //
+    // In the case of a load (or store) operation we want to permit
+    // addresses to be implicitly constructed, e.g. the two calls:
+    //
+    //     load32(Address(addrReg), destReg);
+    //     load32(addrReg, destReg);
+    //
+    // Are equivalent, and the explicit wrapping of the Address in the former
+    // is unnecessary.
+    struct ImplicitAddress {
+        ImplicitAddress(RegisterID base)
+            : base(base)
+            , offset(0)
+        {
+        }
+
+        ImplicitAddress(Address address)
+            : base(address.base)
+            , offset(address.offset)
+        {
+        }
+
+        RegisterID base;
+        int32_t offset;
+    };
+
+    // BaseIndex:
+    //
+    // Describes a complex addressing mode.
+    struct BaseIndex {
+        BaseIndex(RegisterID base, RegisterID index, Scale scale, int32_t offset = 0)
+            : base(base)
+            , index(index)
+            , scale(scale)
+            , offset(offset)
+        {
+        }
+
+        RegisterID base;
+        RegisterID index;
+        Scale scale;
+        int32_t offset;
+    };
+
+    // AbsoluteAddress:
+    //
+    // Describes an memory operand given by a pointer.  For regular load & store
+    // operations an unwrapped void* will be used, rather than using this.
+    struct AbsoluteAddress {
+        explicit AbsoluteAddress(void* ptr)
+            : m_ptr(ptr)
+        {
+        }
+
+        void* m_ptr;
+    };
+
+    // ImmPtr:
+    //
+    // A pointer sized immediate operand to an instruction - this is wrapped
+    // in a class requiring explicit construction in order to differentiate
+    // from pointers used as absolute addresses to memory operations
+    struct ImmPtr {
+        explicit ImmPtr(void* value)
+            : m_value(value)
+        {
+        }
+
+        intptr_t asIntptr()
+        {
+            return reinterpret_cast<intptr_t>(m_value);
+        }
+
+        void* m_value;
+    };
+
+    // Imm32:
+    //
+    // A 32bit immediate operand to an instruction - this is wrapped in a
+    // class requiring explicit construction in order to prevent RegisterIDs
+    // (which are implemented as an enum) from accidentally being passed as
+    // immediate values.
+    struct Imm32 {
+        explicit Imm32(int32_t value)
+            : m_value(value)
+        {
+        }
+
+#if !PLATFORM(X86_64)
+        explicit Imm32(ImmPtr ptr)
+            : m_value(ptr.asIntptr())
+        {
+        }
+#endif
+
+        int32_t m_value;
+    };
+
+
+    // Section 2: MacroAssembler code buffer handles
+    //
+    // The following types are used to reference items in the code buffer
+    // during JIT code generation.  For example, the type Jump is used to
+    // track the location of a jump instruction so that it may later be
+    // linked to a label marking its destination.
+
+
+    // Label:
+    //
+    // A Label records a point in the generated instruction stream, typically such that
+    // it may be used as a destination for a jump.
+    class Label {
+        template<class TemplateAssemblerType>
+        friend class AbstractMacroAssembler;
+        friend class Jump;
+        friend class MacroAssemblerCodeRef;
+        friend class PatchBuffer;
+
+    public:
+        Label()
+        {
+        }
+
+        Label(AbstractMacroAssembler<AssemblerType>* masm)
+            : m_label(masm->m_assembler.label())
+        {
+        }
+        
+        bool isUsed() const { return m_label.isUsed(); }
+        void used() { m_label.used(); }
+    private:
+        JmpDst m_label;
+    };
+
+    // DataLabelPtr:
+    //
+    // A DataLabelPtr is used to refer to a location in the code containing a pointer to be
+    // patched after the code has been generated.
+    class DataLabelPtr {
+        template<class TemplateAssemblerType>
+        friend class AbstractMacroAssembler;
+        friend class PatchBuffer;
+    public:
+        DataLabelPtr()
+        {
+        }
+
+        DataLabelPtr(AbstractMacroAssembler<AssemblerType>* masm)
+            : m_label(masm->m_assembler.label())
+        {
+        }
+        
+    private:
+        JmpDst m_label;
+    };
+
+    // DataLabel32:
+    //
+    // A DataLabelPtr is used to refer to a location in the code containing a pointer to be
+    // patched after the code has been generated.
+    class DataLabel32 {
+        template<class TemplateAssemblerType>
+        friend class AbstractMacroAssembler;
+        friend class PatchBuffer;
+    public:
+        DataLabel32()
+        {
+        }
+
+        DataLabel32(AbstractMacroAssembler<AssemblerType>* masm)
+            : m_label(masm->m_assembler.label())
+        {
+        }
+
+    private:
+        JmpDst m_label;
+    };
+
+    // Call:
+    //
+    // A Call object is a reference to a call instruction that has been planted
+    // into the code buffer - it is typically used to link the call, setting the
+    // relative offset such that when executed it will call to the desired
+    // destination.
+    class Call {
+        template<class TemplateAssemblerType>
+        friend class AbstractMacroAssembler;
+        friend class PatchBuffer;
+    public:
+        enum Flags {
+            None = 0x0,
+            Linkable = 0x1,
+            Near = 0x2,
+            LinkableNear = 0x3,
+        };
+
+        Call()
+            : m_flags(None)
+        {
+        }
+        
+        Call(JmpSrc jmp, Flags flags)
+            : m_jmp(jmp)
+            , m_flags(flags)
+        {
+        }
+
+        bool isFlagSet(Flags flag)
+        {
+            return m_flags & flag;
+        }
+
+        static Call fromTailJump(Jump jump)
+        {
+            return Call(jump.m_jmp, Linkable);
+        }
+
+    private:
+        JmpSrc m_jmp;
+        Flags m_flags;
+    };
+
+    // Jump:
+    //
+    // A jump object is a reference to a jump instruction that has been planted
+    // into the code buffer - it is typically used to link the jump, setting the
+    // relative offset such that when executed it will jump to the desired
+    // destination.
+    class Jump {
+        template<class TemplateAssemblerType>
+        friend class AbstractMacroAssembler;
+        friend class Call;
+        friend class PatchBuffer;
+    public:
+        Jump()
+        {
+        }
+        
+        Jump(JmpSrc jmp)    
+            : m_jmp(jmp)
+        {
+        }
+        
+        void link(AbstractMacroAssembler<AssemblerType>* masm)
+        {
+            masm->m_assembler.linkJump(m_jmp, masm->m_assembler.label());
+        }
+        
+        void linkTo(Label label, AbstractMacroAssembler<AssemblerType>* masm)
+        {
+            masm->m_assembler.linkJump(m_jmp, label.m_label);
+        }
+
+    private:
+        JmpSrc m_jmp;
+    };
+
+    // JumpList:
+    //
+    // A JumpList is a set of Jump objects.
+    // All jumps in the set will be linked to the same destination.
+    class JumpList {
+        friend class PatchBuffer;
+
+    public:
+        void link(AbstractMacroAssembler<AssemblerType>* masm)
+        {
+            size_t size = m_jumps.size();
+            for (size_t i = 0; i < size; ++i)
+                m_jumps[i].link(masm);
+            m_jumps.clear();
+        }
+        
+        void linkTo(Label label, AbstractMacroAssembler<AssemblerType>* masm)
+        {
+            size_t size = m_jumps.size();
+            for (size_t i = 0; i < size; ++i)
+                m_jumps[i].linkTo(label, masm);
+            m_jumps.clear();
+        }
+        
+        void append(Jump jump)
+        {
+            m_jumps.append(jump);
+        }
+        
+        void append(JumpList& other)
+        {
+            m_jumps.append(other.m_jumps.begin(), other.m_jumps.size());
+        }
+
+        bool empty()
+        {
+            return !m_jumps.size();
+        }
+
+    private:
+        Vector<Jump, 16> m_jumps;
+    };
+
+
+    // Section 3: MacroAssembler JIT instruction stream handles.
+    //
+    // The MacroAssembler supported facilities to modify a JIT generated
+    // instruction stream after it has been generated (relinking calls and
+    // jumps, and repatching data values).  The following types are used
+    // to store handles into the underlying instruction stream, the type
+    // providing semantic information as to what it is that is in the
+    // instruction stream at this point, and thus what operations may be
+    // performed on it.
+
+
+    // CodeLocationCommon:
+    //
+    // Base type for other CodeLocation* types.  A postion in the JIT genertaed
+    // instruction stream, without any semantic information.
+    class CodeLocationCommon {
+    public:
+        CodeLocationCommon()
+        {
+        }
+
+        // In order to avoid the need to store multiple handles into the
+        // instructions stream, where the code generation is deterministic
+        // and the labels will always be a fixed distance apart, these
+        // methods may be used to recover a handle that has nopw been
+        // retained, based on a known fixed relative offset from one that has.
+        CodeLocationInstruction instructionAtOffset(int offset);
+        CodeLocationLabel labelAtOffset(int offset);
+        CodeLocationJump jumpAtOffset(int offset);
+        CodeLocationCall callAtOffset(int offset);
+        CodeLocationNearCall nearCallAtOffset(int offset);
+        CodeLocationDataLabelPtr dataLabelPtrAtOffset(int offset);
+        CodeLocationDataLabel32 dataLabel32AtOffset(int offset);
+
+    protected:
+        explicit CodeLocationCommon(CodePtr location)
+            : m_location(location)
+        {
+        }
+
+        void* dataLocation() { return m_location.dataLocation(); }
+        void* executableAddress() { return m_location.executableAddress(); }
+    
+        void reset()
+        {
+            m_location = CodePtr();
+        }
+
+    private:
+        CodePtr m_location;
+    };
+
+    // CodeLocationInstruction:
+    //
+    // An arbitrary instruction in the JIT code.
+    class CodeLocationInstruction : public CodeLocationCommon {
+        friend class CodeLocationCommon;
+    public:
+        CodeLocationInstruction()
+        {
+        }
+
+        void repatchLoadPtrToLEA()
+        {
+            AssemblerType::repatchLoadPtrToLEA(this->dataLocation());
+        }
+
+    private:
+        explicit CodeLocationInstruction(void* location)
+            : CodeLocationCommon(CodePtr(location))
+        {
+        }
+    };
+
+    // CodeLocationLabel:
+    //
+    // A point in the JIT code maked with a label.
+    class CodeLocationLabel : public CodeLocationCommon {
+        friend class CodeLocationCommon;
+        friend class CodeLocationJump;
+        friend class CodeLocationCall;
+        friend class CodeLocationNearCall;
+        friend class PatchBuffer;
+        friend class ProcessorReturnAddress;
+
+    public:
+        CodeLocationLabel()
+        {
+        }
+
+        void* addressForSwitch() { return this->executableAddress(); }
+        void* addressForExceptionHandler() { return this->executableAddress(); }
+        void* addressForJSR() { return this->executableAddress(); }
+
+        bool operator!()
+        {
+            return !this->executableAddress();
+        }
+
+        void reset()
+        {
+            CodeLocationCommon::reset();
+        }
+
+    private:
+        explicit CodeLocationLabel(CodePtr location)
+            : CodeLocationCommon(location)
+        {
+        }
+
+        explicit CodeLocationLabel(void* location)
+            : CodeLocationCommon(CodePtr(location))
+        {
+        }
+
+        void* getJumpDestination() { return this->executableAddress(); }
+    };
+
+    // CodeLocationJump:
+    //
+    // A point in the JIT code at which there is a jump instruction.
+    class CodeLocationJump : public CodeLocationCommon {
+        friend class CodeLocationCommon;
+        friend class PatchBuffer;
+    public:
+        CodeLocationJump()
+        {
+        }
+
+        void relink(CodeLocationLabel destination)
+        {
+            AssemblerType::relinkJump(this->dataLocation(), destination.executableAddress());
+        }
+
+    private:
+        explicit CodeLocationJump(void* location)
+            : CodeLocationCommon(CodePtr(location))
+        {
+        }
+    };
+
+    // CodeLocationCall:
+    //
+    // A point in the JIT code at which there is a call instruction.
+    class CodeLocationCall : public CodeLocationCommon {
+        friend class CodeLocationCommon;
+        friend class PatchBuffer;
+        friend class ProcessorReturnAddress;
+    public:
+        CodeLocationCall()
+        {
+        }
+
+        void relink(CodeLocationLabel destination)
+        {
+#if PLATFORM(X86_64)
+            CodeLocationCommon::dataLabelPtrAtOffset(-REPTACH_OFFSET_CALL_R11).repatch(destination.executableAddress());
+#else
+            AssemblerType::relinkCall(this->dataLocation(), destination.executableAddress());
+#endif
+        }
+
+        void relink(FunctionPtr destination)
+        {
+#if PLATFORM(X86_64)
+            CodeLocationCommon::dataLabelPtrAtOffset(-REPTACH_OFFSET_CALL_R11).repatch(destination.executableAddress());
+#else
+            AssemblerType::relinkCall(this->dataLocation(), destination.executableAddress());
+#endif
+        }
+
+        // This methods returns the value that will be set as the return address
+        // within a function that has been called from this call instruction.
+        void* calleeReturnAddressValue()
+        {
+            return this->executableAddress();
+        }
+
+    private:
+        explicit CodeLocationCall(CodePtr location)
+            : CodeLocationCommon(location)
+        {
+        }
+
+        explicit CodeLocationCall(void* location)
+            : CodeLocationCommon(CodePtr(location))
+        {
+        }
+    };
+
+    // CodeLocationNearCall:
+    //
+    // A point in the JIT code at which there is a call instruction with near linkage.
+    class CodeLocationNearCall : public CodeLocationCommon {
+        friend class CodeLocationCommon;
+        friend class PatchBuffer;
+        friend class ProcessorReturnAddress;
+    public:
+        CodeLocationNearCall()
+        {
+        }
+
+        void relink(CodePtr destination)
+        {
+            AssemblerType::relinkCall(this->dataLocation(), destination.executableAddress());
+        }
+
+        void relink(CodeLocationLabel destination)
+        {
+            AssemblerType::relinkCall(this->dataLocation(), destination.executableAddress());
+        }
+
+        void relink(FunctionPtr destination)
+        {
+            AssemblerType::relinkCall(this->dataLocation(), destination.executableAddress());
+        }
+
+        // This methods returns the value that will be set as the return address
+        // within a function that has been called from this call instruction.
+        void* calleeReturnAddressValue()
+        {
+            return this->executableAddress();
+        }
+
+    private:
+        explicit CodeLocationNearCall(CodePtr location)
+            : CodeLocationCommon(location)
+        {
+        }
+
+        explicit CodeLocationNearCall(void* location)
+            : CodeLocationCommon(CodePtr(location))
+        {
+        }
+    };
+
+    // CodeLocationDataLabel32:
+    //
+    // A point in the JIT code at which there is an int32_t immediate that may be repatched.
+    class CodeLocationDataLabel32 : public CodeLocationCommon {
+        friend class CodeLocationCommon;
+        friend class PatchBuffer;
+    public:
+        CodeLocationDataLabel32()
+        {
+        }
+
+        void repatch(int32_t value)
+        {
+            AssemblerType::repatchInt32(this->dataLocation(), value);
+        }
+
+    private:
+        explicit CodeLocationDataLabel32(void* location)
+            : CodeLocationCommon(CodePtr(location))
+        {
+        }
+    };
+
+    // CodeLocationDataLabelPtr:
+    //
+    // A point in the JIT code at which there is a void* immediate that may be repatched.
+    class CodeLocationDataLabelPtr : public CodeLocationCommon {
+        friend class CodeLocationCommon;
+        friend class PatchBuffer;
+    public:
+        CodeLocationDataLabelPtr()
+        {
+        }
+
+        void repatch(void* value)
+        {
+            AssemblerType::repatchPointer(this->dataLocation(), value);
+        }
+
+    private:
+        explicit CodeLocationDataLabelPtr(void* location)
+            : CodeLocationCommon(CodePtr(location))
+        {
+        }
+    };
+
+    // ProcessorReturnAddress:
+    //
+    // This class can be used to relink a call identified by its return address.
+    class ProcessorReturnAddress {
+        friend class CodeLocationCall;
+        friend class CodeLocationNearCall;
+    public:
+        ProcessorReturnAddress(void* location)
+            : m_location(location)
+        {
+        }
+
+        void relinkCallerToTrampoline(CodeLocationLabel label)
+        {
+            CodeLocationCall(CodePtr(m_location)).relink(label);
+        }
+        
+        void relinkCallerToTrampoline(CodePtr newCalleeFunction)
+        {
+            relinkCallerToTrampoline(CodeLocationLabel(newCalleeFunction));
+        }
+
+        void relinkCallerToFunction(FunctionPtr function)
+        {
+            CodeLocationCall(CodePtr(m_location)).relink(function);
+        }
+        
+        void relinkNearCallerToTrampoline(CodeLocationLabel label)
+        {
+            CodeLocationNearCall(CodePtr(m_location)).relink(label);
+        }
+        
+        void relinkNearCallerToTrampoline(CodePtr newCalleeFunction)
+        {
+            relinkNearCallerToTrampoline(CodeLocationLabel(newCalleeFunction));
+        }
+
+        void* addressForLookup()
+        {
+            return m_location.value();
+        }
+
+    private:
+        ReturnAddressPtr m_location;
+    };
+
+
+    // Section 4: PatchBuffer - utility to finalize code generation.
+
+    static CodePtr trampolineAt(CodeRef ref, Label label)
+    {
+        return CodePtr(AssemblerType::getRelocatedAddress(ref.m_code.dataLocation(), label.m_label));
+    }
+
+    // PatchBuffer:
+    //
+    // This class assists in linking code generated by the macro assembler, once code generation
+    // has been completed, and the code has been copied to is final location in memory.  At this
+    // time pointers to labels within the code may be resolved, and relative offsets to external
+    // addresses may be fixed.
+    //
+    // Specifically:
+    //   * Jump objects may be linked to external targets,
+    //   * The address of Jump objects may taken, such that it can later be relinked.
+    //   * The return address of a Jump object representing a call may be acquired.
+    //   * The address of a Label pointing into the code may be resolved.
+    //   * The value referenced by a DataLabel may be fixed.
+    //
+    // FIXME: distinguish between Calls & Jumps (make a specific call to obtain the return
+    // address of calls, as opposed to a point that can be used to later relink a Jump -
+    // possibly wrap the later up in an object that can do just that).
+    class PatchBuffer : public Noncopyable {
+    public:
+        // Note: Initialization sequence is significant, since executablePool is a PassRefPtr.
+        //       First, executablePool is copied into m_executablePool, then the initialization of
+        //       m_code uses m_executablePool, *not* executablePool, since this is no longer valid.
+        PatchBuffer(AbstractMacroAssembler<AssemblerType>* masm, PassRefPtr<ExecutablePool> executablePool)
+            : m_executablePool(executablePool)
+            , m_code(masm->m_assembler.executableCopy(m_executablePool.get()))
+            , m_size(masm->m_assembler.size())
+#ifndef NDEBUG
+            , m_completed(false)
+#endif
+        {
+        }
+
+        ~PatchBuffer()
+        {
+            ASSERT(m_completed);
+        }
+
+        // These methods are used to link or set values at code generation time.
+
+        void link(Call call, FunctionPtr function)
+        {
+            ASSERT(call.isFlagSet(Call::Linkable));
+#if PLATFORM(X86_64)
+            if (!call.isFlagSet(Call::Near)) {
+                char* callLocation = reinterpret_cast<char*>(AssemblerType::getRelocatedAddress(code(), call.m_jmp)) - REPTACH_OFFSET_CALL_R11;
+                AssemblerType::patchPointerForCall(callLocation, function.value());
+            } else
+#endif
+            AssemblerType::linkCall(code(), call.m_jmp, function.value());
+        }
+        
+        void link(Jump jump, CodeLocationLabel label)
+        {
+            AssemblerType::linkJump(code(), jump.m_jmp, label.executableAddress());
+        }
+
+        void link(JumpList list, CodeLocationLabel label)
+        {
+            for (unsigned i = 0; i < list.m_jumps.size(); ++i)
+                AssemblerType::linkJump(code(), list.m_jumps[i].m_jmp, label.executableAddress());
+        }
+
+        void patch(DataLabelPtr label, void* value)
+        {
+            AssemblerType::patchPointer(code(), label.m_label, value);
+        }
+
+        void patch(DataLabelPtr label, CodeLocationLabel value)
+        {
+            AssemblerType::patchPointer(code(), label.m_label, value.getJumpDestination());
+        }
+
+        // These methods are used to obtain handles to allow the code to be relinked / repatched later.
+
+        CodeLocationCall locationOf(Call call)
+        {
+            ASSERT(call.isFlagSet(Call::Linkable));
+            ASSERT(!call.isFlagSet(Call::Near));
+            return CodeLocationCall(AssemblerType::getRelocatedAddress(code(), call.m_jmp));
+        }
+
+        CodeLocationNearCall locationOfNearCall(Call call)
+        {
+            ASSERT(call.isFlagSet(Call::Linkable));
+            ASSERT(call.isFlagSet(Call::Near));
+            return CodeLocationNearCall(AssemblerType::getRelocatedAddress(code(), call.m_jmp));
+        }
+
+        CodeLocationLabel locationOf(Label label)
+        {
+            return CodeLocationLabel(AssemblerType::getRelocatedAddress(code(), label.m_label));
+        }
+
+        CodeLocationDataLabelPtr locationOf(DataLabelPtr label)
+        {
+            return CodeLocationDataLabelPtr(AssemblerType::getRelocatedAddress(code(), label.m_label));
+        }
+
+        CodeLocationDataLabel32 locationOf(DataLabel32 label)
+        {
+            return CodeLocationDataLabel32(AssemblerType::getRelocatedAddress(code(), label.m_label));
+        }
+
+        // This method obtains the return address of the call, given as an offset from
+        // the start of the code.
+        unsigned returnAddressOffset(Call call)
+        {
+            return AssemblerType::getCallReturnOffset(call.m_jmp);
+        }
+
+        // Upon completion of all patching either 'finalizeCode()' or 'finalizeCodeAddendum()' should be called
+        // once to complete generation of the code.  'finalizeCode()' is suited to situations
+        // where the executable pool must also be retained, the lighter-weight 'finalizeCodeAddendum()' is
+        // suited to adding to an existing allocation.
+        CodeRef finalizeCode()
+        {
+            performFinalization();
+
+            return CodeRef(m_code, m_executablePool, m_size);
+        }
+        CodeLocationLabel finalizeCodeAddendum()
+        {
+            performFinalization();
+
+            return CodeLocationLabel(code());
+        }
+
+    private:
+        // Keep this private! - the underlying code should only be obtained externally via 
+        // finalizeCode() or finalizeCodeAddendum().
+        void* code()
+        {
+            return m_code;
+        }
+
+        void performFinalization()
+        {
+#ifndef NDEBUG
+            ASSERT(!m_completed);
+            m_completed = true;
+#endif
+
+            ExecutableAllocator::makeExecutable(code(), m_size);
+        }
+
+        RefPtr<ExecutablePool> m_executablePool;
+        void* m_code;
+        size_t m_size;
+#ifndef NDEBUG
+        bool m_completed;
+#endif
+    };
+
+
+    // Section 5: Misc admin methods
+
+    size_t size()
+    {
+        return m_assembler.size();
+    }
+
+    Label label()
+    {
+        return Label(this);
+    }
+    
+    Label align()
+    {
+        m_assembler.align(16);
+        return Label(this);
+    }
+
+    ptrdiff_t differenceBetween(Label from, Jump to)
+    {
+        return AssemblerType::getDifferenceBetweenLabels(from.m_label, to.m_jmp);
+    }
+
+    ptrdiff_t differenceBetween(Label from, Call to)
+    {
+        return AssemblerType::getDifferenceBetweenLabels(from.m_label, to.m_jmp);
+    }
+
+    ptrdiff_t differenceBetween(Label from, Label to)
+    {
+        return AssemblerType::getDifferenceBetweenLabels(from.m_label, to.m_label);
+    }
+
+    ptrdiff_t differenceBetween(Label from, DataLabelPtr to)
+    {
+        return AssemblerType::getDifferenceBetweenLabels(from.m_label, to.m_label);
+    }
+
+    ptrdiff_t differenceBetween(Label from, DataLabel32 to)
+    {
+        return AssemblerType::getDifferenceBetweenLabels(from.m_label, to.m_label);
+    }
+
+    ptrdiff_t differenceBetween(DataLabelPtr from, Jump to)
+    {
+        return AssemblerType::getDifferenceBetweenLabels(from.m_label, to.m_jmp);
+    }
+
+    ptrdiff_t differenceBetween(DataLabelPtr from, DataLabelPtr to)
+    {
+        return AssemblerType::getDifferenceBetweenLabels(from.m_label, to.m_label);
+    }
+
+    ptrdiff_t differenceBetween(DataLabelPtr from, Call to)
+    {
+        return AssemblerType::getDifferenceBetweenLabels(from.m_label, to.m_jmp);
+    }
+
+protected:
+    AssemblerType m_assembler;
+};
+
+
+template <class AssemblerType>
+typename AbstractMacroAssembler<AssemblerType>::CodeLocationInstruction AbstractMacroAssembler<AssemblerType>::CodeLocationCommon::instructionAtOffset(int offset)
+{
+    return typename AbstractMacroAssembler::CodeLocationInstruction(reinterpret_cast<char*>(dataLocation()) + offset);
+}
+
+template <class AssemblerType>
+typename AbstractMacroAssembler<AssemblerType>::CodeLocationLabel AbstractMacroAssembler<AssemblerType>::CodeLocationCommon::labelAtOffset(int offset)
+{
+    return typename AbstractMacroAssembler::CodeLocationLabel(reinterpret_cast<char*>(dataLocation()) + offset);
+}
+
+template <class AssemblerType>
+typename AbstractMacroAssembler<AssemblerType>::CodeLocationJump AbstractMacroAssembler<AssemblerType>::CodeLocationCommon::jumpAtOffset(int offset)
+{
+    return typename AbstractMacroAssembler::CodeLocationJump(reinterpret_cast<char*>(dataLocation()) + offset);
+}
+
+template <class AssemblerType>
+typename AbstractMacroAssembler<AssemblerType>::CodeLocationCall AbstractMacroAssembler<AssemblerType>::CodeLocationCommon::callAtOffset(int offset)
+{
+    return typename AbstractMacroAssembler::CodeLocationCall(reinterpret_cast<char*>(dataLocation()) + offset);
+}
+
+template <class AssemblerType>
+typename AbstractMacroAssembler<AssemblerType>::CodeLocationNearCall AbstractMacroAssembler<AssemblerType>::CodeLocationCommon::nearCallAtOffset(int offset)
+{
+    return typename AbstractMacroAssembler::CodeLocationNearCall(reinterpret_cast<char*>(dataLocation()) + offset);
+}
+
+template <class AssemblerType>
+typename AbstractMacroAssembler<AssemblerType>::CodeLocationDataLabelPtr AbstractMacroAssembler<AssemblerType>::CodeLocationCommon::dataLabelPtrAtOffset(int offset)
+{
+    return typename AbstractMacroAssembler::CodeLocationDataLabelPtr(reinterpret_cast<char*>(dataLocation()) + offset);
+}
+
+template <class AssemblerType>
+typename AbstractMacroAssembler<AssemblerType>::CodeLocationDataLabel32 AbstractMacroAssembler<AssemblerType>::CodeLocationCommon::dataLabel32AtOffset(int offset)
+{
+    return typename AbstractMacroAssembler::CodeLocationDataLabel32(reinterpret_cast<char*>(dataLocation()) + offset);
+}
+
+} // namespace JSC
+
+#endif // ENABLE(ASSEMBLER)
+
+#endif // AbstractMacroAssembler_h