//===-- PrologEpilogInserter.cpp - Insert Prolog/Epilog code in function --===//
-//
+//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
-//
+//
//===----------------------------------------------------------------------===//
//
// This pass is responsible for finalizing the functions frame layout, saving
}
private:
- std::vector<unsigned> RegsToSave;
+ std::vector<std::pair<unsigned, const TargetRegisterClass*> > RegsToSave;
std::vector<int> StackSlots;
void calculateCallerSavedRegisters(MachineFunction &Fn);
void PEI::calculateCallerSavedRegisters(MachineFunction &Fn) {
const MRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo();
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;
for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); )
if (I->getOpcode() == FrameSetupOpcode ||
I->getOpcode() == FrameDestroyOpcode) {
- assert(I->getNumOperands() == 1 && "Call Frame Setup/Destroy Pseudo"
+ assert(I->getNumOperands() >= 1 && "Call Frame Setup/Destroy Pseudo"
" instructions should have a single immediate argument!");
unsigned Size = I->getOperand(0).getImmedValue();
if (Size > MaxCallFrameSize) MaxCallFrameSize = Size;
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.
//
+ const bool *PhysRegsUsed = Fn.getUsedPhysregs();
+ const TargetRegisterClass* const *CSRegClasses =
+ RegInfo->getCalleeSaveRegClasses();
for (unsigned i = 0; CSRegs[i]; ++i) {
unsigned Reg = CSRegs[i];
- if (ModifiedRegs[Reg]) {
- RegsToSave.push_back(Reg); // If modified register...
+ if (PhysRegsUsed[Reg]) {
+ // If the reg is modified, save it!
+ RegsToSave.push_back(std::make_pair(Reg, CSRegClasses[i]));
} else {
for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
- *AliasSet; ++AliasSet) { // Check alias registers too...
- if (ModifiedRegs[*AliasSet]) {
- RegsToSave.push_back(Reg);
+ *AliasSet; ++AliasSet) { // Check alias registers too.
+ if (PhysRegsUsed[*AliasSet]) {
+ RegsToSave.push_back(std::make_pair(Reg, CSRegClasses[i]));
break;
}
}
// Now that we know which registers need to be saved and restored, allocate
// stack slots for them.
for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) {
- unsigned Reg = RegsToSave[i];
- int FrameIdx;
- const TargetRegisterClass *RC = RegInfo->getRegClass(Reg);
+ unsigned Reg = RegsToSave[i].first;
+ const TargetRegisterClass *RC = RegsToSave[i].second;
// Check to see if this physreg must be spilled to a particular stack slot
// on this target.
FixedSlot->first != Reg)
++FixedSlot;
+ int FrameIdx;
if (FixedSlot == FixedSpillSlots+NumFixedSpillSlots) {
// Nope, just spill it anywhere convenient.
FrameIdx = FFI->CreateStackObject(RC->getSize(), RC->getAlignment());
void PEI::saveCallerSavedRegisters(MachineFunction &Fn) {
// Early exit if no caller saved registers are modified!
if (RegsToSave.empty())
- return;
+ 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) {
// Insert the spill to the stack frame.
- RegInfo->storeRegToStackSlot(*MBB, I, RegsToSave[i], StackSlots[i]);
+ RegInfo->storeRegToStackSlot(*MBB, I, RegsToSave[i].first, StackSlots[i],
+ RegsToSave[i].second);
}
// 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;
+ // Skip over all terminator instructions, which are part of the return
+ // sequence.
+ MachineBasicBlock::iterator I2 = I;
+ while (I2 != MBB->begin() && TII.isTerminatorInstr((--I2)->getOpcode()))
+ I = I2;
+
+ bool AtStart = I == MBB->begin();
+ MachineBasicBlock::iterator BeforeI = I;
+ if (!AtStart)
+ --BeforeI;
+
+ // Restore all registers immediately before the return and any terminators
+ // that preceed it.
for (unsigned i = 0, e = RegsToSave.size(); i != e; ++i) {
- RegInfo->loadRegFromStackSlot(*MBB, I, RegsToSave[i],StackSlots[i]);
- --I; // Insert in reverse order
+ RegInfo->loadRegFromStackSlot(*MBB, I, RegsToSave[i].first,
+ StackSlots[i], RegsToSave[i].second);
+ assert(I != MBB->begin() &&
+ "loadRegFromStackSlot didn't insert any code!");
+ // Insert in reverse order. loadRegFromStackSlot can insert multiple
+ // instructions.
+ if (AtStart)
+ I = MBB->begin();
+ else {
+ I = BeforeI;
+ ++I;
+ }
}
}
- }
}
/// 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();
-
+
bool StackGrowsDown =
TFI.getStackGrowthDirection() == TargetFrameInfo::StackGrowsDown;
-
+
// Loop over all of the stack objects, assigning sequential addresses...
MachineFrameInfo *FFI = Fn.getFrameInfo();
int Offset = TFI.getOffsetOfLocalArea();
if (StackGrowsDown)
Offset = -Offset;
- assert(Offset >= 0
+ assert(Offset >= 0
&& "Local area offset should be in direction of stack growth");
// If there are fixed sized objects that are preallocated in the local area,
// non-fixed objects can't be allocated right at the start of local area.
- // We currently don't support filling in holes in between fixed sized objects,
+ // We currently don't support filling in holes in between fixed sized objects,
// so we adjust 'Offset' to point to the end of last fixed sized
// preallocated object.
for (int i = FFI->getObjectIndexBegin(); i != 0; ++i) {
// the offset is negative, so we negate the offset to get the distance.
FixedOff = -FFI->getObjectOffset(i);
} else {
- // The maximum distance from the start pointer is at the upper
+ // The maximum distance from the start pointer is at the upper
// address of the object.
FixedOff = FFI->getObjectOffset(i) + FFI->getObjectSize(i);
- }
- if (FixedOff > Offset) Offset = FixedOff;
+ }
+ if (FixedOff > Offset) Offset = FixedOff;
}
for (unsigned i = 0, e = FFI->getObjectIndexEnd(); i != e; ++i) {
assert(Align <= StackAlignment && "Cannot align stack object to higher "
"alignment boundary than the stack itself!");
Offset = (Offset+Align-1)/Align*Align; // Adjust to Alignment boundary...
-
+
if (StackGrowsDown) {
FFI->setObjectOffset(i, -Offset); // Set the computed offset
} else {
- FFI->setObjectOffset(i, Offset);
+ FFI->setObjectOffset(i, Offset);
Offset += FFI->getObjectSize(i);
}
}
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