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Move estimateStackSize from ARM into MachineFrameInfo

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This is a generic function (derived from PEI); moving it into
MachineFrameInfo eliminates a current redundancy between the ARM and AArch64
backends, and will allow it to be used by the PowerPC target code.

No functionality change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177111 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hal Finkel
2013-03-14 21:15:20 +00:00
parent 3080d23fde
commit 0cc52c67db
4 changed files with 55 additions and 108 deletions
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57
lib/Target/ARM/ARMFrameLowering.cpp
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@@ -1038,58 +1038,6 @@ static unsigned GetFunctionSizeInBytes(const MachineFunction &MF,
return FnSize;
}
/// estimateStackSize - Estimate and return the size of the frame.
/// FIXME: Make generic?
static unsigned estimateStackSize(MachineFunction &MF) {
const MachineFrameInfo *MFI = MF.getFrameInfo();
const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
const TargetRegisterInfo *RegInfo = MF.getTarget().getRegisterInfo();
unsigned MaxAlign = MFI->getMaxAlignment();
int Offset = 0;
// This code is very, very similar to PEI::calculateFrameObjectOffsets().
// It really should be refactored to share code. Until then, changes
// should keep in mind that there's tight coupling between the two.
for (int i = MFI->getObjectIndexBegin(); i != 0; ++i) {
int FixedOff = -MFI->getObjectOffset(i);
if (FixedOff > Offset) Offset = FixedOff;
}
for (unsigned i = 0, e = MFI->getObjectIndexEnd(); i != e; ++i) {
if (MFI->isDeadObjectIndex(i))
continue;
Offset += MFI->getObjectSize(i);
unsigned Align = MFI->getObjectAlignment(i);
// Adjust to alignment boundary
Offset = (Offset+Align-1)/Align*Align;
MaxAlign = std::max(Align, MaxAlign);
}
if (MFI->adjustsStack() && TFI->hasReservedCallFrame(MF))
Offset += MFI->getMaxCallFrameSize();
// Round up the size to a multiple of the alignment. If the function has
// any calls or alloca's, align to the target's StackAlignment value to
// ensure that the callee's frame or the alloca data is suitably aligned;
// otherwise, for leaf functions, align to the TransientStackAlignment
// value.
unsigned StackAlign;
if (MFI->adjustsStack() || MFI->hasVarSizedObjects() ||
(RegInfo->needsStackRealignment(MF) && MFI->getObjectIndexEnd() != 0))
StackAlign = TFI->getStackAlignment();
else
StackAlign = TFI->getTransientStackAlignment();
// If the frame pointer is eliminated, all frame offsets will be relative to
// SP not FP. Align to MaxAlign so this works.
StackAlign = std::max(StackAlign, MaxAlign);
unsigned AlignMask = StackAlign - 1;
Offset = (Offset + AlignMask) & ~uint64_t(AlignMask);
return (unsigned)Offset;
}
/// estimateRSStackSizeLimit - Look at each instruction that references stack
/// frames and return the stack size limit beyond which some of these
/// instructions will require a scratch register during their expansion later.
@@ -1235,7 +1183,7 @@ ARMFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
// we've used all the registers and so R4 is already used, so not marking
// it here will be OK.
// FIXME: It will be better just to find spare register here.
unsigned StackSize = estimateStackSize(MF);
unsigned StackSize = MFI->estimateStackSize(MF);
if (MFI->hasVarSizedObjects() || StackSize > 508)
MRI.setPhysRegUsed(ARM::R4);
}
@@ -1330,7 +1278,8 @@ ARMFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
// worth the effort and added fragility?
bool BigStack =
(RS &&
(estimateStackSize(MF) + ((hasFP(MF) && AFI->hasStackFrame()) ? 4:0) >=
(MFI->estimateStackSize(MF) +
((hasFP(MF) && AFI->hasStackFrame()) ? 4:0) >=
estimateRSStackSizeLimit(MF, this)))
|| MFI->hasVarSizedObjects()
|| (MFI->adjustsStack() && !canSimplifyCallFramePseudos(MF));