void
TR::AMD64ABILinkage::mapIncomingParms(
TR::ResolvedMethodSymbol *method,
uint32_t &stackIndex)
{
ListIterator<TR::ParameterSymbol> parameterIterator(&method->getParameterList());
TR::ParameterSymbol *parmCursor = parameterIterator.getFirst();
if (!parmCursor) return;
if (parmCursor->getLinkageRegisterIndex() < 0)
{
copyLinkageInfoToParameterSymbols();
}
// 1st: handle parameters which are passed through stack
//
TR::X86SystemLinkage::mapIncomingParms(method);
// 2nd: handle parameters which are passed through linkage registers, but are
// not assigned any register after RA (or say, by their first usage point,
// a MOV is needed to load it from stack to register).
//
// AMD64 SysV ABI says that: a parameter is placed either in registers or
// pushed on the stack, but can't take both. So, for parms passed through
// linkage registers but don't have physical registers assigned after RA,
// we will allocate stack space in local variable region.
//
for (parmCursor = parameterIterator.getFirst(); parmCursor; parmCursor = parameterIterator.getNext())
{
if ((parmCursor->getLinkageRegisterIndex() >= 0) && (parmCursor->getAllocatedIndex() < 0 || hasToBeOnStack(parmCursor)))
{
uint32_t align = getAlignment(parmCursor->getDataType());
uint32_t alignMinus1 = (align <= AMD64_STACK_SLOT_SIZE) ? (AMD64_STACK_SLOT_SIZE - 1) : (align - 1);
uint32_t pos = -stackIndex;
pos += parmCursor->getSize();
pos = (pos + alignMinus1) & (~alignMinus1);
stackIndex = -pos;
parmCursor->setParameterOffset(stackIndex);
if (comp()->getOption(TR_TraceCG))
traceMsg(comp(), "mapIncomingParms setParameterOffset %d for param symbol (reg param without home location) %p, hasToBeOnStack() %d\n", parmCursor->getParameterOffset(), parmCursor, hasToBeOnStack(parmCursor));
}
else if (parmCursor->getLinkageRegisterIndex() >=0 && parmCursor->getAllocatedIndex() >= 0)
{
//parmCursor->setDontHaveStackSlot(0); // this is a hack , so as we could print stack layout table in createPrologue
if (comp()->getOption(TR_TraceCG))
traceMsg(comp(), "mapIncomingParms no need to set parm %p, for it has got register %d assigned\n", parmCursor, parmCursor->getAllocatedIndex());
}
}
}
