gistfile1.txt

class ReadSlotStubImpl
{
  protected:
    virtual void branchExit(MacroAssembler &masm, Assembler::Condition cond, Address addr,
                            ImmGCPtr ptr) = 0;
    virtual void jumpRejoin(MacroAssembler &masm) = 0;
    virtual void jumpExit(MacroAssembler &masm) = 0;
    virtual void bindFailures(MacroAssembler &masm) = 0;

  public:
    void generateReadSlot(JSContext *cx, MacroAssembler &masm, JSObject *obj, PropertyName *propName,
                          JSObject *holder, HandleShape shape, Register object, TypedOrValueRegister output,
                          Label *nonRepatchFailures = NULL)
    {
        // If there's a single jump to |failures|, we can patch the shape guard
        // jump directly. Otherwise, jump to the end of the stub, so there's a
        // common point to patch.
        bool multipleFailureJumps = (nonRepatchFailures != NULL) && nonRepatchFailures->used();
        branchExit(masm, Assembler::NotEqual,
                   Address(object, JSObject::offsetOfShape()),
                   ImmGCPtr(obj->lastProperty()));
        ...
    }
};

class GetNativePropertyStub : public ReadSlotStubImpl
{
    RepatchLabel *failures_;

  protected:
    void branchExit(MacroAssembler &masm, Assembler::Condition cond, Address addr, ImmGCPtr ptr) {
        exitOffset = masm.branchPtrWithPatch(cond, addr, ptr, failures_);
    }

    void jumpRejoin(MacroAssembler &masm) {
        RepatchLabel rejoin_;
        rejoinOffset = masm.jumpWithPatch(&rejoin_);
        masm.bind(&rejoin_);
    }

    void jumpExit(MacroAssembler &masm) {
        RepatchLabel exit_;
        exitOffset = masm.jumpWithPatch(&exit_);
        masm.bind(&exit_);
    }

    void bindFailures(MacroAssembler &masm) {
        masm.bind(failures_);
    }

  public:
    CodeOffsetJump exitOffset;
    CodeOffsetJump rejoinOffset;
    CodeOffsetLabel stubCodePatchOffset;

    void generateReadSlot(JSContext *cx, MacroAssembler &masm, JSObject *obj, PropertyName *propName,
                          JSObject *holder, HandleShape shape, Register object, TypedOrValueRegister output,
                          RepatchLabel *failures, Label *nonRepatchFailures = NULL)
    {
        this->failures_ = failures;
        ReadSlotStubImpl::generateReadSlot(cx, masm, obj, propName, holder, shape, object,
                                           output, nonRepatchFailures);
    }
};
class ParallelReadSlotStub : public ReadSlotStubImpl
{
    Label failures_;
    Label *rejoin_;
    Label *exit_;

  protected:
    void branchExit(MacroAssembler &masm, Assembler::Condition cond, Address addr, ImmGCPtr ptr) {
        masm.branchPtr(cond, addr, ptr, &failures_);
    }

    void jumpRejoin(MacroAssembler &masm) {
        masm.jump(rejoin_);
    }

    void jumpExit(MacroAssembler &masm) {
        masm.jump(exit_);
    }

    void bindFailures(MacroAssembler &masm) {
        masm.bind(&failures_);
    }

  public:
    void generateReadSlot(JSContext *cx, MacroAssembler &masm, JSObject *obj, PropertyName *propName,
                          JSObject *holder, HandleShape shape, Register object, TypedOrValueRegister output,
                          Label *rejoin, Label *exit, Label *nonRepatchFailures = NULL)
    {
        this->rejoin_ = rejoin;
        this->exit_ = exit;
        ReadSlotStubImpl::generateReadSlot(cx, masm, obj, propName, holder, shape, object,
                                           output, nonRepatchFailures);
    }
};