switch to having the callee pop stack operands for fastcc. This is currently buggy

do not use


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21984 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2005-05-13 21:44:04 +00:00
parent 2a82ef317c
commit 3648c67eb2
3 changed files with 43 additions and 16 deletions

View File

@ -109,6 +109,11 @@ namespace {
addLegalFPImmediate(-1.0); // FLD1/FCHS
}
// Return the number of bytes that a function should pop when it returns (in
// addition to the space used by the return address).
//
unsigned getBytesToPopOnReturn() const { return BytesToPopOnReturn; }
/// LowerArguments - This hook must be implemented to indicate how we should
/// lower the arguments for the specified function, into the specified DAG.
virtual std::vector<SDOperand>
@ -228,7 +233,8 @@ X86TargetLowering::LowerCCCArguments(Function &F, SelectionDAG &DAG) {
// the start of the first vararg value... for expansion of llvm.va_start.
if (F.isVarArg())
VarArgsFrameIndex = MFI->CreateFixedObject(1, ArgOffset);
ReturnAddrIndex = 0; // No return address slot generated yet.
ReturnAddrIndex = 0; // No return address slot generated yet.
BytesToPopOnReturn = 0; // Callee pops nothing.
// Finally, inform the code generator which regs we return values in.
switch (getValueType(F.getReturnType())) {
@ -527,11 +533,9 @@ X86TargetLowering::LowerFastCCArguments(Function &F, SelectionDAG &DAG) {
ArgOffset += ArgIncrement; // Move on to the next argument.
}
// If the function takes variable number of arguments, make a frame index for
// the start of the first vararg value... for expansion of llvm.va_start.
if (F.isVarArg())
VarArgsFrameIndex = MFI->CreateFixedObject(1, ArgOffset);
ReturnAddrIndex = 0; // No return address slot generated yet.
VarArgsFrameIndex = 0xAAAAAAA; // fastcc functions can't have varargs.
ReturnAddrIndex = 0; // No return address slot generated yet.
BytesToPopOnReturn = ArgOffset; // Callee pops all stack arguments.
// Finally, inform the code generator which regs we return values in.
switch (getValueType(F.getReturnType())) {
@ -3518,7 +3522,10 @@ void ISel::Select(SDOperand N) {
Select(N.getOperand(0));
break;
}
BuildMI(BB, X86::RET, 0); // Just emit a 'ret' instruction
if (X86Lowering.getBytesToPopOnReturn() == 0)
BuildMI(BB, X86::RET, 0); // Just emit a 'ret' instruction
else
BuildMI(BB, X86::RETI, 1).addImm(X86Lowering.getBytesToPopOnReturn());
return;
case ISD::BR: {
Select(N.getOperand(0));
@ -3721,13 +3728,19 @@ void ISel::Select(SDOperand N) {
return;
}
case ISD::CALLSEQ_START:
Select(N.getOperand(0));
// Stack amount
Tmp1 = cast<ConstantSDNode>(N.getOperand(1))->getValue();
BuildMI(BB, X86::ADJCALLSTACKDOWN, 1).addImm(Tmp1);
return;
case ISD::CALLSEQ_END:
Select(N.getOperand(0));
// Stack amount
Tmp1 = cast<ConstantSDNode>(N.getOperand(1))->getValue();
Opc = N.getOpcode() == ISD::CALLSEQ_START ? X86::ADJCALLSTACKDOWN :
X86::ADJCALLSTACKUP;
BuildMI(BB, Opc, 1).addImm(Tmp1);
// Amount the callee added to the stack pointer.
Tmp2 = cast<ConstantSDNode>(N.getOperand(2))->getValue();
BuildMI(BB, X86::ADJCALLSTACKUP, 2).addImm(Tmp1).addImm(Tmp2);
return;
case ISD::MEMSET: {
Select(N.getOperand(0)); // Select the chain.

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@ -1695,7 +1695,7 @@ void X86ISel::doCall(const ValueRecord &Ret, MachineInstr *CallMI,
BB->push_back(CallMI);
BuildMI(BB, X86::ADJCALLSTACKUP, 1).addImm(NumBytes);
BuildMI(BB, X86::ADJCALLSTACKUP, 2).addImm(NumBytes).addImm(0);
// If there is a return value, scavenge the result from the location the call
// leaves it in...

View File

@ -375,17 +375,31 @@ eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
unsigned Align = MF.getTarget().getFrameInfo()->getStackAlignment();
Amount = (Amount+Align-1)/Align*Align;
MachineInstr *New;
MachineInstr *New = 0;
if (Old->getOpcode() == X86::ADJCALLSTACKDOWN) {
New=BuildMI(X86::SUB32ri, 1, X86::ESP, MachineOperand::UseAndDef)
.addZImm(Amount);
} else {
assert(Old->getOpcode() == X86::ADJCALLSTACKUP);
New=BuildMI(X86::ADD32ri, 1, X86::ESP, MachineOperand::UseAndDef)
.addZImm(Amount);
// factor out the amount the callee already popped.
unsigned CalleeAmt = Old->getOperand(1).getImmedValue();
Amount -= CalleeAmt;
if (Amount)
New = BuildMI(X86::ADD32ri, 1, X86::ESP,
MachineOperand::UseAndDef).addZImm(Amount);
}
// Replace the pseudo instruction with a new instruction...
if (New) MBB.insert(I, New);
}
} else if (I->getOpcode() == X86::ADJCALLSTACKUP) {
// If we are performing frame pointer elimination and if the callee pops
// something off the stack pointer, add it back. We do this until we have
// more advanced stack pointer tracking ability.
if (unsigned CalleeAmt = I->getOperand(1).getImmedValue()) {
MachineInstr *New =
BuildMI(X86::SUB32ri, 1, X86::ESP,
MachineOperand::UseAndDef).addZImm(CalleeAmt);
MBB.insert(I, New);
}
}
@ -513,8 +527,8 @@ void X86RegisterInfo::emitEpilogue(MachineFunction &MF,
unsigned NumBytes = MFI->getStackSize();
if (NumBytes) { // adjust stack pointer back: ESP += numbytes
MI =BuildMI(X86::ADD32ri, 1, X86::ESP, MachineOperand::UseAndDef)
.addZImm(NumBytes);
MI = BuildMI(X86::ADD32ri, 1, X86::ESP, MachineOperand::UseAndDef)
.addZImm(NumBytes);
MBB.insert(MBBI, MI);
}
}