bool MIRParserImpl::initializeFrameInfo(
const Function &F, MachineFrameInfo &MFI,
const yaml::MachineFunction &YamlMF,
DenseMap<unsigned, int> &StackObjectSlots,
DenseMap<unsigned, int> &FixedStackObjectSlots) {
const yaml::MachineFrameInfo &YamlMFI = YamlMF.FrameInfo;
MFI.setFrameAddressIsTaken(YamlMFI.IsFrameAddressTaken);
MFI.setReturnAddressIsTaken(YamlMFI.IsReturnAddressTaken);
MFI.setHasStackMap(YamlMFI.HasStackMap);
MFI.setHasPatchPoint(YamlMFI.HasPatchPoint);
MFI.setStackSize(YamlMFI.StackSize);
MFI.setOffsetAdjustment(YamlMFI.OffsetAdjustment);
if (YamlMFI.MaxAlignment)
MFI.ensureMaxAlignment(YamlMFI.MaxAlignment);
MFI.setAdjustsStack(YamlMFI.AdjustsStack);
MFI.setHasCalls(YamlMFI.HasCalls);
MFI.setMaxCallFrameSize(YamlMFI.MaxCallFrameSize);
MFI.setHasOpaqueSPAdjustment(YamlMFI.HasOpaqueSPAdjustment);
MFI.setHasVAStart(YamlMFI.HasVAStart);
MFI.setHasMustTailInVarArgFunc(YamlMFI.HasMustTailInVarArgFunc);
// Initialize the fixed frame objects.
for (const auto &Object : YamlMF.FixedStackObjects) {
int ObjectIdx;
if (Object.Type != yaml::FixedMachineStackObject::SpillSlot)
ObjectIdx = MFI.CreateFixedObject(Object.Size, Object.Offset,
Object.IsImmutable, Object.IsAliased);
else
ObjectIdx = MFI.CreateFixedSpillStackObject(Object.Size, Object.Offset);
MFI.setObjectAlignment(ObjectIdx, Object.Alignment);
// TODO: Report an error when objects are redefined.
FixedStackObjectSlots.insert(std::make_pair(Object.ID, ObjectIdx));
}
// Initialize the ordinary frame objects.
for (const auto &Object : YamlMF.StackObjects) {
int ObjectIdx;
const AllocaInst *Alloca = nullptr;
const yaml::StringValue &Name = Object.Name;
if (!Name.Value.empty()) {
Alloca = dyn_cast_or_null<AllocaInst>(
F.getValueSymbolTable().lookup(Name.Value));
if (!Alloca)
return error(Name.SourceRange.Start,
"alloca instruction named '" + Name.Value +
"' isn't defined in the function '" + F.getName() +
"'");
}
if (Object.Type == yaml::MachineStackObject::VariableSized)
ObjectIdx = MFI.CreateVariableSizedObject(Object.Alignment, Alloca);
else
ObjectIdx = MFI.CreateStackObject(
Object.Size, Object.Alignment,
Object.Type == yaml::MachineStackObject::SpillSlot, Alloca);
MFI.setObjectOffset(ObjectIdx, Object.Offset);
// TODO: Report an error when objects are redefined.
StackObjectSlots.insert(std::make_pair(Object.ID, ObjectIdx));
}
return false;
}
/// calculateCalleeSavedRegisters - Scan the function for modified callee saved
/// registers.
void PEI::calculateCalleeSavedRegisters(MachineFunction &F) {
const TargetRegisterInfo *RegInfo = F.getSubtarget().getRegisterInfo();
const TargetFrameLowering *TFI = F.getSubtarget().getFrameLowering();
MachineFrameInfo *MFI = F.getFrameInfo();
// Get the callee saved register list...
const MCPhysReg *CSRegs = RegInfo->getCalleeSavedRegs(&F);
// These are used to keep track the callee-save area. Initialize them.
MinCSFrameIndex = INT_MAX;
MaxCSFrameIndex = 0;
// Early exit for targets which have no callee saved registers.
if (!CSRegs || CSRegs[0] == 0)
return;
// In Naked functions we aren't going to save any registers.
if (F.getFunction()->hasFnAttribute(Attribute::Naked))
return;
std::vector<CalleeSavedInfo> CSI;
for (unsigned i = 0; CSRegs[i]; ++i) {
unsigned Reg = CSRegs[i];
// Functions which call __builtin_unwind_init get all their registers saved.
if (F.getRegInfo().isPhysRegUsed(Reg) || F.getMMI().callsUnwindInit()) {
// If the reg is modified, save it!
CSI.push_back(CalleeSavedInfo(Reg));
}
}
if (!TFI->assignCalleeSavedSpillSlots(F, RegInfo, CSI)) {
// If target doesn't implement this, use generic code.
if (CSI.empty())
return; // Early exit if no callee saved registers are modified!
unsigned NumFixedSpillSlots;
const TargetFrameLowering::SpillSlot *FixedSpillSlots =
TFI->getCalleeSavedSpillSlots(NumFixedSpillSlots);
// Now that we know which registers need to be saved and restored, allocate
// stack slots for them.
for (std::vector<CalleeSavedInfo>::iterator I = CSI.begin(), E = CSI.end();
I != E; ++I) {
unsigned Reg = I->getReg();
const TargetRegisterClass *RC = RegInfo->getMinimalPhysRegClass(Reg);
int FrameIdx;
if (RegInfo->hasReservedSpillSlot(F, Reg, FrameIdx)) {
I->setFrameIdx(FrameIdx);
continue;
}
// Check to see if this physreg must be spilled to a particular stack slot
// on this target.
const TargetFrameLowering::SpillSlot *FixedSlot = FixedSpillSlots;
while (FixedSlot != FixedSpillSlots + NumFixedSpillSlots &&
FixedSlot->Reg != Reg)
++FixedSlot;
if (FixedSlot == FixedSpillSlots + NumFixedSpillSlots) {
// Nope, just spill it anywhere convenient.
unsigned Align = RC->getAlignment();
unsigned StackAlign = TFI->getStackAlignment();
// We may not be able to satisfy the desired alignment specification of
// the TargetRegisterClass if the stack alignment is smaller. Use the
// min.
Align = std::min(Align, StackAlign);
FrameIdx = MFI->CreateStackObject(RC->getSize(), Align, true);
if ((unsigned)FrameIdx < MinCSFrameIndex) MinCSFrameIndex = FrameIdx;
if ((unsigned)FrameIdx > MaxCSFrameIndex) MaxCSFrameIndex = FrameIdx;
} else {
// Spill it to the stack where we must.
FrameIdx =
MFI->CreateFixedSpillStackObject(RC->getSize(), FixedSlot->Offset);
}
I->setFrameIdx(FrameIdx);
}
}
MFI->setCalleeSavedInfo(CSI);
}
void PEI::assignCalleeSavedSpillSlots(MachineFunction &F,
const BitVector &SavedRegs) {
// These are used to keep track the callee-save area. Initialize them.
MinCSFrameIndex = INT_MAX;
MaxCSFrameIndex = 0;
if (SavedRegs.empty())
return;
const TargetRegisterInfo *RegInfo = F.getSubtarget().getRegisterInfo();
const MCPhysReg *CSRegs = RegInfo->getCalleeSavedRegs(&F);
std::vector<CalleeSavedInfo> CSI;
for (unsigned i = 0; CSRegs[i]; ++i) {
unsigned Reg = CSRegs[i];
if (SavedRegs.test(Reg))
CSI.push_back(CalleeSavedInfo(Reg));
}
const TargetFrameLowering *TFI = F.getSubtarget().getFrameLowering();
MachineFrameInfo *MFI = F.getFrameInfo();
if (!TFI->assignCalleeSavedSpillSlots(F, RegInfo, CSI)) {
// If target doesn't implement this, use generic code.
if (CSI.empty())
return; // Early exit if no callee saved registers are modified!
unsigned NumFixedSpillSlots;
const TargetFrameLowering::SpillSlot *FixedSpillSlots =
TFI->getCalleeSavedSpillSlots(NumFixedSpillSlots);
// Now that we know which registers need to be saved and restored, allocate
// stack slots for them.
for (auto &CS : CSI) {
unsigned Reg = CS.getReg();
const TargetRegisterClass *RC = RegInfo->getMinimalPhysRegClass(Reg);
int FrameIdx;
if (RegInfo->hasReservedSpillSlot(F, Reg, FrameIdx)) {
CS.setFrameIdx(FrameIdx);
continue;
}
// Check to see if this physreg must be spilled to a particular stack slot
// on this target.
const TargetFrameLowering::SpillSlot *FixedSlot = FixedSpillSlots;
while (FixedSlot != FixedSpillSlots + NumFixedSpillSlots &&
FixedSlot->Reg != Reg)
++FixedSlot;
if (FixedSlot == FixedSpillSlots + NumFixedSpillSlots) {
// Nope, just spill it anywhere convenient.
unsigned Align = RC->getAlignment();
unsigned StackAlign = TFI->getStackAlignment();
// We may not be able to satisfy the desired alignment specification of
// the TargetRegisterClass if the stack alignment is smaller. Use the
// min.
Align = std::min(Align, StackAlign);
FrameIdx = MFI->CreateStackObject(RC->getSize(), Align, true);
if ((unsigned)FrameIdx < MinCSFrameIndex) MinCSFrameIndex = FrameIdx;
if ((unsigned)FrameIdx > MaxCSFrameIndex) MaxCSFrameIndex = FrameIdx;
} else {
// Spill it to the stack where we must.
FrameIdx =
MFI->CreateFixedSpillStackObject(RC->getSize(), FixedSlot->Offset);
}
CS.setFrameIdx(FrameIdx);
}
}
MFI->setCalleeSavedInfo(CSI);
}
