void JIT::compileLoadVarargs(Instruction* instruction)
{
    int thisValue = instruction[2].u.operand;
    int arguments = instruction[3].u.operand;
    int firstFreeRegister = instruction[4].u.operand;

    JumpList slowCase;
    JumpList end;
    if (m_codeBlock->usesArguments() && arguments == m_codeBlock->argumentsRegister()) {
        emitLoadTag(arguments, regT1);
        slowCase.append(branch32(NotEqual, regT1, TrustedImm32(JSValue::EmptyValueTag)));

        load32(payloadFor(RegisterFile::ArgumentCount), regT2);
        slowCase.append(branch32(Above, regT2, TrustedImm32(Arguments::MaxArguments + 1)));
        // regT2: argumentCountIncludingThis

        move(regT2, regT3);
        add32(TrustedImm32(firstFreeRegister + RegisterFile::CallFrameHeaderSize), regT3);
        lshift32(TrustedImm32(3), regT3);
        addPtr(callFrameRegister, regT3);
        // regT3: newCallFrame

        slowCase.append(branchPtr(Below, AbsoluteAddress(m_globalData->interpreter->registerFile().addressOfEnd()), regT3));

        // Initialize ArgumentCount.
        store32(regT2, payloadFor(RegisterFile::ArgumentCount, regT3));

        // Initialize 'this'.
        emitLoad(thisValue, regT1, regT0);
        store32(regT0, Address(regT3, OBJECT_OFFSETOF(JSValue, u.asBits.payload) + (CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register)))));
        store32(regT1, Address(regT3, OBJECT_OFFSETOF(JSValue, u.asBits.tag) + (CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register)))));

        // Copy arguments.
        neg32(regT2);
        end.append(branchAdd32(Zero, TrustedImm32(1), regT2));
        // regT2: -argumentCount;

        Label copyLoop = label();
        load32(BaseIndex(callFrameRegister, regT2, TimesEight, OBJECT_OFFSETOF(JSValue, u.asBits.payload) +(CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register)))), regT0);
        load32(BaseIndex(callFrameRegister, regT2, TimesEight, OBJECT_OFFSETOF(JSValue, u.asBits.tag) +(CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register)))), regT1);
        store32(regT0, BaseIndex(regT3, regT2, TimesEight, OBJECT_OFFSETOF(JSValue, u.asBits.payload) +(CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register)))));
        store32(regT1, BaseIndex(regT3, regT2, TimesEight, OBJECT_OFFSETOF(JSValue, u.asBits.tag) +(CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register)))));
        branchAdd32(NonZero, TrustedImm32(1), regT2).linkTo(copyLoop, this);

        end.append(jump());
    }

    if (m_codeBlock->usesArguments() && arguments == m_codeBlock->argumentsRegister())
        slowCase.link(this);

    JITStubCall stubCall(this, cti_op_load_varargs);
    stubCall.addArgument(thisValue);
    stubCall.addArgument(arguments);
    stubCall.addArgument(Imm32(firstFreeRegister));
    stubCall.call(regT3);

    if (m_codeBlock->usesArguments() && arguments == m_codeBlock->argumentsRegister())
        end.link(this);
}
Exemple #2
0
void JIT::compileLoadVarargs(Instruction* instruction)
{
    int thisValue = instruction[3].u.operand;
    int arguments = instruction[4].u.operand;
    int firstFreeRegister = instruction[5].u.operand;

    JumpList slowCase;
    JumpList end;
    bool canOptimize = m_codeBlock->usesArguments()
        && VirtualRegister(arguments) == m_codeBlock->argumentsRegister()
        && !m_codeBlock->symbolTable()->slowArguments();

    if (canOptimize) {
        emitLoadTag(arguments, regT1);
        slowCase.append(branch32(NotEqual, regT1, TrustedImm32(JSValue::EmptyValueTag)));

        load32(payloadFor(JSStack::ArgumentCount), regT2);
        slowCase.append(branch32(Above, regT2, TrustedImm32(Arguments::MaxArguments + 1)));
        // regT2: argumentCountIncludingThis

        move(regT2, regT3);
        neg32(regT3);
        add32(TrustedImm32(firstFreeRegister - JSStack::CallFrameHeaderSize), regT3);
        lshift32(TrustedImm32(3), regT3);
        addPtr(callFrameRegister, regT3);
        // regT3: newCallFrame

        slowCase.append(branchPtr(Above, AbsoluteAddress(m_vm->interpreter->stack().addressOfEnd()), regT3));

        // Initialize ArgumentCount.
        store32(regT2, payloadFor(JSStack::ArgumentCount, regT3));

        // Initialize 'this'.
        emitLoad(thisValue, regT1, regT0);
        store32(regT0, Address(regT3, OBJECT_OFFSETOF(JSValue, u.asBits.payload) + (CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register)))));
        store32(regT1, Address(regT3, OBJECT_OFFSETOF(JSValue, u.asBits.tag) + (CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register)))));

        // Copy arguments.
        end.append(branchSub32(Zero, TrustedImm32(1), regT2));
        // regT2: argumentCount;

        Label copyLoop = label();
        load32(BaseIndex(callFrameRegister, regT2, TimesEight, OBJECT_OFFSETOF(JSValue, u.asBits.payload) +(CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register)))), regT0);
        load32(BaseIndex(callFrameRegister, regT2, TimesEight, OBJECT_OFFSETOF(JSValue, u.asBits.tag) +(CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register)))), regT1);
        store32(regT0, BaseIndex(regT3, regT2, TimesEight, OBJECT_OFFSETOF(JSValue, u.asBits.payload) +(CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register)))));
        store32(regT1, BaseIndex(regT3, regT2, TimesEight, OBJECT_OFFSETOF(JSValue, u.asBits.tag) +(CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register)))));
        branchSub32(NonZero, TrustedImm32(1), regT2).linkTo(copyLoop, this);

        end.append(jump());
    }

    if (canOptimize)
        slowCase.link(this);

    emitLoad(thisValue, regT1, regT0);
    emitLoad(arguments, regT3, regT2);
    callOperation(operationLoadVarargs, regT1, regT0, regT3, regT2, firstFreeRegister);
    move(returnValueRegister, regT3);

    if (canOptimize)
        end.link(this);
}