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()
&& arguments == m_codeBlock->argumentsRegister().offset()
&& !m_codeBlock->symbolTable()->slowArguments();
if (canOptimize) {
emitGetVirtualRegister(arguments, regT0);
slowCase.append(branch64(NotEqual, regT0, TrustedImm64(JSValue::encode(JSValue()))));
emitGetFromCallFrameHeader32(JSStack::ArgumentCount, regT0);
slowCase.append(branch32(Above, regT0, TrustedImm32(Arguments::MaxArguments + 1)));
// regT0: argumentCountIncludingThis
move(regT0, regT1);
neg64(regT1);
add64(TrustedImm32(firstFreeRegister - JSStack::CallFrameHeaderSize), regT1);
lshift64(TrustedImm32(3), regT1);
addPtr(callFrameRegister, regT1);
// regT1: newCallFrame
slowCase.append(branchPtr(Above, AbsoluteAddress(m_vm->addressOfJSStackLimit()), regT1));
// Initialize ArgumentCount.
store32(regT0, Address(regT1, JSStack::ArgumentCount * static_cast<int>(sizeof(Register)) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.payload)));
// Initialize 'this'.
emitGetVirtualRegister(thisValue, regT2);
store64(regT2, Address(regT1, CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register))));
// Copy arguments.
signExtend32ToPtr(regT0, regT0);
end.append(branchSub64(Zero, TrustedImm32(1), regT0));
// regT0: argumentCount
Label copyLoop = label();
load64(BaseIndex(callFrameRegister, regT0, TimesEight, CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register))), regT2);
store64(regT2, BaseIndex(regT1, regT0, TimesEight, CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register))));
branchSub64(NonZero, TrustedImm32(1), regT0).linkTo(copyLoop, this);
end.append(jump());
}
if (canOptimize)
slowCase.link(this);
emitGetVirtualRegister(thisValue, regT0);
emitGetVirtualRegister(arguments, regT1);
callOperation(operationLoadVarargs, regT0, regT1, firstFreeRegister);
move(returnValueGPR, regT1);
if (canOptimize)
end.link(this);
}
void JIT::compileLoadVarargs(Instruction* instruction)
{
int thisValue = instruction[3].u.operand;
int arguments = instruction[4].u.operand;
int firstFreeRegister = instruction[5].u.operand;
int firstVarArgOffset = instruction[6].u.operand;
JumpList slowCase;
JumpList end;
bool canOptimize = m_codeBlock->usesArguments()
&& arguments == m_codeBlock->argumentsRegister().offset()
&& !m_codeBlock->symbolTable()->slowArguments();
if (canOptimize) {
emitGetVirtualRegister(arguments, regT0);
slowCase.append(branch64(NotEqual, regT0, TrustedImm64(JSValue::encode(JSValue()))));
emitGetFromCallFrameHeader32(JSStack::ArgumentCount, regT0);
if (firstVarArgOffset) {
Jump sufficientArguments = branch32(GreaterThan, regT0, TrustedImm32(firstVarArgOffset + 1));
move(TrustedImm32(1), regT0);
Jump endVarArgs = jump();
sufficientArguments.link(this);
sub32(TrustedImm32(firstVarArgOffset), regT0);
endVarArgs.link(this);
}
slowCase.append(branch32(Above, regT0, TrustedImm32(Arguments::MaxArguments + 1)));
// regT0: argumentCountIncludingThis
move(regT0, regT1);
add64(TrustedImm32(-firstFreeRegister + JSStack::CallFrameHeaderSize), regT1);
// regT1 now has the required frame size in Register units
// Round regT1 to next multiple of stackAlignmentRegisters()
add64(TrustedImm32(stackAlignmentRegisters() - 1), regT1);
and64(TrustedImm32(~(stackAlignmentRegisters() - 1)), regT1);
neg64(regT1);
lshift64(TrustedImm32(3), regT1);
addPtr(callFrameRegister, regT1);
// regT1: newCallFrame
slowCase.append(branchPtr(Above, AbsoluteAddress(m_vm->addressOfStackLimit()), regT1));
// Initialize ArgumentCount.
store32(regT0, Address(regT1, JSStack::ArgumentCount * static_cast<int>(sizeof(Register)) + OBJECT_OFFSETOF(EncodedValueDescriptor, asBits.payload)));
// Initialize 'this'.
emitGetVirtualRegister(thisValue, regT2);
store64(regT2, Address(regT1, CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register))));
// Copy arguments.
signExtend32ToPtr(regT0, regT0);
end.append(branchSub64(Zero, TrustedImm32(1), regT0));
// regT0: argumentCount
Label copyLoop = label();
load64(BaseIndex(callFrameRegister, regT0, TimesEight, (CallFrame::thisArgumentOffset() + firstVarArgOffset) * static_cast<int>(sizeof(Register))), regT2);
store64(regT2, BaseIndex(regT1, regT0, TimesEight, CallFrame::thisArgumentOffset() * static_cast<int>(sizeof(Register))));
branchSub64(NonZero, TrustedImm32(1), regT0).linkTo(copyLoop, this);
end.append(jump());
}
if (canOptimize)
slowCase.link(this);
emitGetVirtualRegister(arguments, regT1);
callOperation(operationSizeFrameForVarargs, regT1, firstFreeRegister, firstVarArgOffset);
move(returnValueGPR, stackPointerRegister);
emitGetVirtualRegister(thisValue, regT1);
emitGetVirtualRegister(arguments, regT2);
callOperation(operationLoadVarargs, returnValueGPR, regT1, regT2, firstVarArgOffset);
move(returnValueGPR, regT1);
if (canOptimize)
end.link(this);
addPtr(TrustedImm32(sizeof(CallerFrameAndPC)), regT1, stackPointerRegister);
}