// code for any caller saved registers that are modified. Also calculate
// the MaxCallFrameSize and HasCalls variables for the function's frame
// information and eliminates call frame pseudo instructions.
+ calculateCallerSavedRegisters(Fn);
+
+ // Add the code to save and restore the caller saved registers
saveCallerSavedRegisters(Fn);
// Allow the target machine to make final modifications to the function
// Calculate actual frame offsets for all of the abstract stack objects...
calculateFrameObjectOffsets(Fn);
- // Add prolog and epilog code to the function.
+ // Add prolog and epilog code to the function. This function is required
+ // to align the stack frame as necessary for any stack variables or
+ // called functions. Because of this, calculateCallerSavedRegisters
+ // must be called before this function in order to set the HasCalls
+ // and MaxCallFrameSize variables.
insertPrologEpilogCode(Fn);
// Replace all MO_FrameIndex operands with physical register references
// and actual offsets.
//
replaceFrameIndices(Fn);
+
+ RegsToSave.clear();
+ StackSlots.clear();
return true;
}
private:
+ std::vector<unsigned> RegsToSave;
+ std::vector<int> StackSlots;
+
+ void calculateCallerSavedRegisters(MachineFunction &Fn);
void saveCallerSavedRegisters(MachineFunction &Fn);
void calculateFrameObjectOffsets(MachineFunction &Fn);
void replaceFrameIndices(MachineFunction &Fn);
FunctionPass *llvm::createPrologEpilogCodeInserter() { return new PEI(); }
-/// saveCallerSavedRegisters - Scan the function for modified caller saved
-/// registers and insert spill code for any caller saved registers that are
-/// modified. Also calculate the MaxCallFrameSize and HasCalls variables for
+/// calculateCallerSavedRegisters - Scan the function for modified caller saved
+/// registers. Also calculate the MaxCallFrameSize and HasCalls variables for
/// the function's frame information and eliminates call frame pseudo
/// instructions.
///
-void PEI::saveCallerSavedRegisters(MachineFunction &Fn) {
+void PEI::calculateCallerSavedRegisters(MachineFunction &Fn) {
const MRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo();
- const TargetFrameInfo &FrameInfo = *Fn.getTarget().getFrameInfo();
+ const TargetFrameInfo *TFI = Fn.getTarget().getFrameInfo();
+ const TargetInstrInfo &TII = *Fn.getTarget().getInstrInfo();
// Get the callee saved register list...
const unsigned *CSRegs = RegInfo->getCalleeSaveRegs();
FrameSetupOpcode == -1 && FrameDestroyOpcode == -1)
return;
- // This bitset contains an entry for each physical register for the target...
- std::vector<bool> ModifiedRegs(RegInfo->getNumRegs());
unsigned MaxCallFrameSize = 0;
bool HasCalls = false;
HasCalls = true;
RegInfo->eliminateCallFramePseudoInstr(Fn, *BB, I++);
} else {
- for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
- MachineOperand &MO = I->getOperand(i);
- if (MO.isRegister() && MO.isDef()) {
- assert(MRegisterInfo::isPhysicalRegister(MO.getReg()) &&
- "Register allocation must be performed!");
- ModifiedRegs[MO.getReg()] = true; // Register is modified
- }
- }
++I;
}
// Now figure out which *callee saved* registers are modified by the current
// function, thus needing to be saved and restored in the prolog/epilog.
//
- std::vector<unsigned> RegsToSave;
+ const bool *PhysRegsUsed = Fn.getUsedPhysregs();
for (unsigned i = 0; CSRegs[i]; ++i) {
unsigned Reg = CSRegs[i];
- if (ModifiedRegs[Reg]) {
- RegsToSave.push_back(Reg); // If modified register...
+ if (PhysRegsUsed[Reg]) {
+ RegsToSave.push_back(Reg); // If the reg is modified, save it!
} else {
for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
- *AliasSet; ++AliasSet) { // Check alias registers too...
- if (ModifiedRegs[*AliasSet]) {
+ *AliasSet; ++AliasSet) { // Check alias registers too.
+ if (PhysRegsUsed[*AliasSet]) {
RegsToSave.push_back(Reg);
break;
}
if (RegsToSave.empty())
return; // Early exit if no caller saved registers are modified!
+ unsigned NumFixedSpillSlots;
+ const std::pair<unsigned,int> *FixedSpillSlots =
+ TFI->getCalleeSaveSpillSlots(NumFixedSpillSlots);
+
// Now that we know which registers need to be saved and restored, allocate
// stack slots for them.
- std::vector<int> StackSlots;
for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) {
- int FrameIdx = FFI->CreateStackObject(RegInfo->getRegClass(RegsToSave[i]));
+ unsigned Reg = RegsToSave[i];
+
+ // Check to see if this physreg must be spilled to a particular stack slot
+ // on this target.
+ const std::pair<unsigned,int> *FixedSlot = FixedSpillSlots;
+ while (FixedSlot != FixedSpillSlots+NumFixedSpillSlots &&
+ FixedSlot->first != Reg)
+ ++FixedSlot;
+
+ int FrameIdx;
+ if (FixedSlot == FixedSpillSlots+NumFixedSpillSlots) {
+ // Nope, just spill it anywhere convenient.
+ FrameIdx = FFI->CreateStackObject(RegInfo->getSpillSize(Reg)/8,
+ RegInfo->getSpillAlignment(Reg)/8);
+ } else {
+ // Spill it to the stack where we must.
+ FrameIdx = FFI->CreateFixedObject(RegInfo->getSpillSize(Reg)/8,
+ FixedSlot->second);
+ }
StackSlots.push_back(FrameIdx);
}
+}
+
+/// saveCallerSavedRegisters - Insert spill code for any caller saved registers
+/// that are modified in the function.
+///
+void PEI::saveCallerSavedRegisters(MachineFunction &Fn) {
+ // Early exit if no caller saved registers are modified!
+ if (RegsToSave.empty())
+ return;
+
+ const MRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo();
// Now that we have a stack slot for each register to be saved, insert spill
- // code into the entry block...
+ // code into the entry block.
MachineBasicBlock *MBB = Fn.begin();
MachineBasicBlock::iterator I = MBB->begin();
for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) {
- const TargetRegisterClass *RC = RegInfo->getRegClass(RegsToSave[i]);
-
- // Insert the spill to the stack frame...
- RegInfo->storeRegToStackSlot(*MBB, I, RegsToSave[i], StackSlots[i], RC);
+ // Insert the spill to the stack frame.
+ RegInfo->storeRegToStackSlot(*MBB, I, RegsToSave[i], StackSlots[i]);
}
// Add code to restore the callee-save registers in each exiting block.
const TargetInstrInfo &TII = *Fn.getTarget().getInstrInfo();
- for (MachineFunction::iterator FI = Fn.begin(), E = Fn.end(); FI != E; ++FI) {
- // If last instruction is a return instruction, add an epilogue
+ for (MachineFunction::iterator FI = Fn.begin(), E = Fn.end(); FI != E; ++FI)
+ // If last instruction is a return instruction, add an epilogue.
if (!FI->empty() && TII.isReturn(FI->back().getOpcode())) {
MBB = FI;
I = MBB->end(); --I;
for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) {
- const TargetRegisterClass *RC = RegInfo->getRegClass(RegsToSave[i]);
- RegInfo->loadRegFromStackSlot(*MBB, I, RegsToSave[i],StackSlots[i], RC);
+ RegInfo->loadRegFromStackSlot(*MBB, I, RegsToSave[i], StackSlots[i]);
+ assert(I != MBB->begin() &&
+ "loadRegFromStackSlot didn't insert any code!");
--I; // Insert in reverse order
}
}
- }
}
/// calculateFrameObjectOffsets - Calculate actual frame offsets for all of the
-/// abstract stack objects...
+/// abstract stack objects.
///
void PEI::calculateFrameObjectOffsets(MachineFunction &Fn) {
const TargetFrameInfo &TFI = *Fn.getTarget().getFrameInfo();
if (I->getOperand(i).isFrameIndex()) {
// If this instruction has a FrameIndex operand, we need to use that
// target machine register info object to eliminate it.
- MRI.eliminateFrameIndex(Fn, I);
+ MRI.eliminateFrameIndex(I);
break;
}
}
projects / oota-llvm.git / blobdiff