BitVector Reserved(getNumRegs());
Reserved.set(ARM::SP);
Reserved.set(ARM::PC);
+ Reserved.set(ARM::FPSCR);
if (STI.isTargetDarwin() || hasFP(MF))
Reserved.set(FramePtr);
// Some targets reserve R9.
bool ARMBaseRegisterInfo::
needsStackRealignment(const MachineFunction &MF) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
+ const Function *F = MF.getFunction();
const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
unsigned StackAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
- return (RealignStack &&
- !AFI->isThumb1OnlyFunction() &&
- (MFI->getMaxAlignment() > StackAlign) &&
- !MFI->hasVarSizedObjects());
+ bool requiresRealignment = ((MFI->getMaxAlignment() > StackAlign) ||
+ F->hasFnAttr(Attribute::StackAlignment));
+
+ // FIXME: Currently we don't support stack realignment for functions with
+ // variable-sized allocas.
+ // FIXME: It's more complicated than this...
+ if (0 && requiresRealignment && MFI->hasVarSizedObjects())
+ report_fatal_error(
+ "Stack realignment in presense of dynamic allocas is not supported");
+
+ // FIXME: This probably isn't the right place for this.
+ if (0 && requiresRealignment && AFI->isThumb1OnlyFunction())
+ report_fatal_error(
+ "Stack realignment in thumb1 functions is not supported");
+
+ return requiresRealignment && canRealignStack(MF);
}
bool ARMBaseRegisterInfo::
return Limit;
}
+static unsigned GetFunctionSizeInBytes(const MachineFunction &MF,
+ const ARMBaseInstrInfo &TII) {
+ unsigned FnSize = 0;
+ for (MachineFunction::const_iterator MBBI = MF.begin(), E = MF.end();
+ MBBI != E; ++MBBI) {
+ const MachineBasicBlock &MBB = *MBBI;
+ for (MachineBasicBlock::const_iterator I = MBB.begin(),E = MBB.end();
+ I != E; ++I)
+ FnSize += TII.GetInstSizeInBytes(I);
+ }
+ return FnSize;
+}
+
void
ARMBaseRegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
RegScavenger *RS) const {
bool ForceLRSpill = false;
if (!LRSpilled && AFI->isThumb1OnlyFunction()) {
- unsigned FnSize = TII.GetFunctionSizeInBytes(MF);
+ unsigned FnSize = GetFunctionSizeInBytes(MF, TII);
// Force LR to be spilled if the Thumb function size is > 2048. This enables
// use of BL to implement far jump. If it turns out that it's not needed
// then the branch fix up path will undo it.
// slot of the previous FP. Also, if we have variable sized objects in the
// function, stack slot references will often be negative, and some of
// our instructions are positive-offset only, so conservatively consider
- // that case to want a spill slot (or register) as well.
+ // that case to want a spill slot (or register) as well. Similarly, if
+ // the function adjusts the stack pointer during execution and the
+ // adjustments aren't already part of our stack size estimate, our offset
+ // calculations may be off, so be conservative.
// FIXME: We could add logic to be more precise about negative offsets
// and which instructions will need a scratch register for them. Is it
// worth the effort and added fragility?
- bool BigStack = RS &&
- (estimateStackSize(MF) + (hasFP(MF) ? 4:0) >= estimateRSStackSizeLimit(MF))
- || MFI->hasVarSizedObjects();
+ bool BigStack =
+ (RS && (estimateStackSize(MF) + (hasFP(MF) ? 4:0) >=
+ estimateRSStackSizeLimit(MF)))
+ || MFI->hasVarSizedObjects()
+ || (MFI->adjustsStack() && !canSimplifyCallFramePseudos(MF));
bool ExtraCSSpill = false;
if (BigStack || !CanEliminateFrame || cannotEliminateFrame(MF)) {
return ARM::SP;
}
+// Provide a base+offset reference to an FI slot for debug info. It's the
+// same as what we use for resolving the code-gen references for now.
+// FIXME: This can go wrong when references are SP-relative and simple call
+// frames aren't used.
int
ARMBaseRegisterInfo::getFrameIndexReference(const MachineFunction &MF, int FI,
unsigned &FrameReg) const {
+ return ResolveFrameIndexReference(MF, FI, FrameReg, 0);
+}
+
+int
+ARMBaseRegisterInfo::ResolveFrameIndexReference(const MachineFunction &MF,
+ int FI,
+ unsigned &FrameReg,
+ int SPAdj) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
int Offset = MFI->getObjectOffset(FI) + MFI->getStackSize();
+ int FPOffset = Offset - AFI->getFramePtrSpillOffset();
bool isFixed = MFI->isFixedObjectIndex(FI);
FrameReg = ARM::SP;
+ Offset += SPAdj;
if (AFI->isGPRCalleeSavedArea1Frame(FI))
- Offset -= AFI->getGPRCalleeSavedArea1Offset();
+ return Offset - AFI->getGPRCalleeSavedArea1Offset();
else if (AFI->isGPRCalleeSavedArea2Frame(FI))
- Offset -= AFI->getGPRCalleeSavedArea2Offset();
+ return Offset - AFI->getGPRCalleeSavedArea2Offset();
else if (AFI->isDPRCalleeSavedAreaFrame(FI))
- Offset -= AFI->getDPRCalleeSavedAreaOffset();
- else if (needsStackRealignment(MF)) {
- // When dynamically realigning the stack, use the frame pointer for
- // parameters, and the stack pointer for locals.
+ return Offset - AFI->getDPRCalleeSavedAreaOffset();
+
+ // When dynamically realigning the stack, use the frame pointer for
+ // parameters, and the stack pointer for locals.
+ if (needsStackRealignment(MF)) {
assert (hasFP(MF) && "dynamic stack realignment without a FP!");
if (isFixed) {
FrameReg = getFrameRegister(MF);
- Offset -= AFI->getFramePtrSpillOffset();
+ Offset = FPOffset;
}
- } else if (hasFP(MF) && AFI->hasStackFrame()) {
+ return Offset;
+ }
+
+ // If there is a frame pointer, use it when we can.
+ if (hasFP(MF) && AFI->hasStackFrame()) {
+ // Use frame pointer to reference fixed objects. Use it for locals if
+ // there are VLAs (and thus the SP isn't reliable as a base).
if (isFixed || MFI->hasVarSizedObjects()) {
- // Use frame pointer to reference fixed objects unless this is a
- // frameless function.
FrameReg = getFrameRegister(MF);
- Offset -= AFI->getFramePtrSpillOffset();
+ Offset = FPOffset;
} else if (AFI->isThumb2Function()) {
- // In Thumb2 mode, the negative offset is very limited.
- int FPOffset = Offset - AFI->getFramePtrSpillOffset();
+ // In Thumb2 mode, the negative offset is very limited. Try to avoid
+ // out of range references.
if (FPOffset >= -255 && FPOffset < 0) {
FrameReg = getFrameRegister(MF);
Offset = FPOffset;
}
+ } else if (Offset > (FPOffset < 0 ? -FPOffset : FPOffset)) {
+ // Otherwise, use SP or FP, whichever is closer to the stack slot.
+ FrameReg = getFrameRegister(MF);
+ Offset = FPOffset;
}
}
return Offset;
}
-
int
ARMBaseRegisterInfo::getFrameIndexOffset(const MachineFunction &MF,
int FI) const {
// add/sub sp brackets around call sites. Returns true if the call frame is
// included as part of the stack frame.
bool ARMBaseRegisterInfo::
-hasReservedCallFrame(MachineFunction &MF) const {
+hasReservedCallFrame(const MachineFunction &MF) const {
const MachineFrameInfo *FFI = MF.getFrameInfo();
unsigned CFSize = FFI->getMaxCallFrameSize();
// It's not always a good idea to include the call frame as part of the
// is not sufficient here since we still may reference some objects via SP
// even when FP is available in Thumb2 mode.
bool ARMBaseRegisterInfo::
-canSimplifyCallFramePseudos(MachineFunction &MF) const {
+canSimplifyCallFramePseudos(const MachineFunction &MF) const {
return hasReservedCallFrame(MF) || MF.getFrameInfo()->hasVarSizedObjects();
}
int FrameIndex = MI.getOperand(i).getIndex();
unsigned FrameReg;
- int Offset = getFrameIndexReference(MF, FrameIndex, FrameReg);
- if (FrameReg != ARM::SP)
- SPAdj = 0;
- Offset += SPAdj;
+ int Offset = ResolveFrameIndexReference(MF, FrameIndex, FrameReg, SPAdj);
// Special handling of dbg_value instructions.
if (MI.isDebugValue()) {
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