eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
const TargetFrameInfo *TFI = MF.getTarget().getFrameInfo();
-
- if (!TFI->hasReservedCallFrame(MF)) {
+ bool reseveCallFrame = TFI->hasReservedCallFrame(MF);
+ int Opcode = I->getOpcode();
+ bool isDestroy = Opcode == getCallFrameDestroyOpcode();
+ DebugLoc DL = I->getDebugLoc();
+ uint64_t Amount = !reseveCallFrame ? I->getOperand(0).getImm() : 0;
+ uint64_t CalleeAmt = isDestroy ? I->getOperand(1).getImm() : 0;
+ I = MBB.erase(I);
+
+ if (!reseveCallFrame) {
// If the stack pointer can be changed after prologue, turn the
// adjcallstackup instruction into a 'sub ESP, <amt>' and the
// adjcallstackdown instruction into 'add ESP, <amt>'
// TODO: consider using push / pop instead of sub + store / add
- MachineInstr *Old = I;
- uint64_t Amount = Old->getOperand(0).getImm();
- if (Amount != 0) {
- // We need to keep the stack aligned properly. To do this, we round the
- // amount of space needed for the outgoing arguments up to the next
- // alignment boundary.
- Amount = (Amount + StackAlign - 1) / StackAlign * StackAlign;
-
- MachineInstr *New = 0;
- if (Old->getOpcode() == getCallFrameSetupOpcode()) {
- New = BuildMI(MF, Old->getDebugLoc(),
- TII.get(getSUBriOpcode(Is64Bit, Amount)),
- StackPtr)
- .addReg(StackPtr)
- .addImm(Amount);
- } else {
- assert(Old->getOpcode() == getCallFrameDestroyOpcode());
-
- // Factor out the amount the callee already popped.
- uint64_t CalleeAmt = Old->getOperand(1).getImm();
- Amount -= CalleeAmt;
+ if (Amount == 0)
+ return;
+
+ // We need to keep the stack aligned properly. To do this, we round the
+ // amount of space needed for the outgoing arguments up to the next
+ // alignment boundary.
+ Amount = (Amount + StackAlign - 1) / StackAlign * StackAlign;
+
+ MachineInstr *New = 0;
+ if (Opcode == getCallFrameSetupOpcode()) {
+ New = BuildMI(MF, DL, TII.get(getSUBriOpcode(Is64Bit, Amount)),
+ StackPtr)
+ .addReg(StackPtr)
+ .addImm(Amount);
+ } else {
+ assert(Opcode == getCallFrameDestroyOpcode());
+
+ // Factor out the amount the callee already popped.
+ Amount -= CalleeAmt;
if (Amount) {
- unsigned Opc = getADDriOpcode(Is64Bit, Amount);
- New = BuildMI(MF, Old->getDebugLoc(), TII.get(Opc), StackPtr)
- .addReg(StackPtr)
- .addImm(Amount);
- }
- }
-
- if (New) {
- // The EFLAGS implicit def is dead.
- New->getOperand(3).setIsDead();
-
- // Replace the pseudo instruction with a new instruction.
- MBB.insert(I, New);
+ unsigned Opc = getADDriOpcode(Is64Bit, Amount);
+ New = BuildMI(MF, DL, TII.get(Opc), StackPtr)
+ .addReg(StackPtr).addImm(Amount);
}
}
- } else if (I->getOpcode() == getCallFrameDestroyOpcode()) {
- // 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 (uint64_t CalleeAmt = I->getOperand(1).getImm()) {
- unsigned Opc = getSUBriOpcode(Is64Bit, CalleeAmt);
- MachineInstr *Old = I;
- MachineInstr *New =
- BuildMI(MF, Old->getDebugLoc(), TII.get(Opc),
- StackPtr)
- .addReg(StackPtr)
- .addImm(CalleeAmt);
+ if (New) {
// The EFLAGS implicit def is dead.
New->getOperand(3).setIsDead();
+
+ // Replace the pseudo instruction with a new instruction.
MBB.insert(I, New);
}
+
+ return;
}
- MBB.erase(I);
+ if (Opcode == getCallFrameDestroyOpcode() && CalleeAmt) {
+ // 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.
+ unsigned Opc = getSUBriOpcode(Is64Bit, CalleeAmt);
+ MachineInstr *New = BuildMI(MF, DL, TII.get(Opc), StackPtr)
+ .addReg(StackPtr).addImm(CalleeAmt);
+
+ // The EFLAGS implicit def is dead.
+ New->getOperand(3).setIsDead();
+ MBB.insert(I, New);
+ }
}
void