Esempi in C++ (Cpp) per CCallHelpers::branchSubPtr

Esempio n. 1

File: SetupVarargsFrame.cpp Progetto: LuXiong/webkit

void emitSetupVarargsFrameFastCase(CCallHelpers& jit, GPRReg numUsedSlotsGPR, GPRReg scratchGPR1, GPRReg scratchGPR2, GPRReg scratchGPR3, ValueRecovery argCountRecovery, VirtualRegister firstArgumentReg, unsigned firstVarArgOffset, CCallHelpers::JumpList& slowCase)
{
    CCallHelpers::JumpList end;
    
    if (argCountRecovery.isConstant()) {
        // FIXME: We could constant-fold a lot of the computation below in this case.
        // https://bugs.webkit.org/show_bug.cgi?id=141486
        jit.move(CCallHelpers::TrustedImm32(argCountRecovery.constant().asInt32()), scratchGPR1);
    } else
        jit.load32(CCallHelpers::payloadFor(argCountRecovery.virtualRegister()), scratchGPR1);
    if (firstVarArgOffset) {
        CCallHelpers::Jump sufficientArguments = jit.branch32(CCallHelpers::GreaterThan, scratchGPR1, CCallHelpers::TrustedImm32(firstVarArgOffset + 1));
        jit.move(CCallHelpers::TrustedImm32(1), scratchGPR1);
        CCallHelpers::Jump endVarArgs = jit.jump();
        sufficientArguments.link(&jit);
        jit.sub32(CCallHelpers::TrustedImm32(firstVarArgOffset), scratchGPR1);
        endVarArgs.link(&jit);
    }
    slowCase.append(jit.branch32(CCallHelpers::Above, scratchGPR1, CCallHelpers::TrustedImm32(maxArguments + 1)));
    
    emitSetVarargsFrame(jit, scratchGPR1, true, numUsedSlotsGPR, scratchGPR2);

    slowCase.append(jit.branchPtr(CCallHelpers::Above, CCallHelpers::AbsoluteAddress(jit.vm()->addressOfStackLimit()), scratchGPR2));

    // Initialize ArgumentCount.
    jit.store32(scratchGPR1, CCallHelpers::Address(scratchGPR2, JSStack::ArgumentCount * static_cast<int>(sizeof(Register)) + PayloadOffset));

    // Copy arguments.
    jit.signExtend32ToPtr(scratchGPR1, scratchGPR1);
    CCallHelpers::Jump done = jit.branchSubPtr(CCallHelpers::Zero, CCallHelpers::TrustedImm32(1), scratchGPR1);
    // scratchGPR1: argumentCount

    CCallHelpers::Label copyLoop = jit.label();
    int argOffset = (firstArgumentReg.offset() - 1 + firstVarArgOffset) * static_cast<int>(sizeof(Register));
#if USE(JSVALUE64)
    jit.load64(CCallHelpers::BaseIndex(GPRInfo::callFrameRegister, scratchGPR1, CCallHelpers::TimesEight, argOffset), scratchGPR3);
    jit.store64(scratchGPR3, CCallHelpers::BaseIndex(scratchGPR2, scratchGPR1, CCallHelpers::TimesEight, CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register))));
#else // USE(JSVALUE64), so this begins the 32-bit case
    jit.load32(CCallHelpers::BaseIndex(GPRInfo::callFrameRegister, scratchGPR1, CCallHelpers::TimesEight, argOffset + TagOffset), scratchGPR3);
    jit.store32(scratchGPR3, CCallHelpers::BaseIndex(scratchGPR2, scratchGPR1, CCallHelpers::TimesEight, CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register)) + TagOffset));
    jit.load32(CCallHelpers::BaseIndex(GPRInfo::callFrameRegister, scratchGPR1, CCallHelpers::TimesEight, argOffset + PayloadOffset), scratchGPR3);
    jit.store32(scratchGPR3, CCallHelpers::BaseIndex(scratchGPR2, scratchGPR1, CCallHelpers::TimesEight, CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register)) + PayloadOffset));
#endif // USE(JSVALUE64), end of 32-bit case
    jit.branchSubPtr(CCallHelpers::NonZero, CCallHelpers::TrustedImm32(1), scratchGPR1).linkTo(copyLoop, &jit);
    
    done.link(&jit);
}