VNInfo *SplitEditor::defValue(unsigned RegIdx,
const VNInfo *ParentVNI,
SlotIndex Idx) {
assert(ParentVNI && "Mapping NULL value");
assert(Idx.isValid() && "Invalid SlotIndex");
assert(Edit->getParent().getVNInfoAt(Idx) == ParentVNI && "Bad Parent VNI");
LiveInterval *LI = Edit->get(RegIdx);
// Create a new value.
VNInfo *VNI = LI->getNextValue(Idx, 0, LIS.getVNInfoAllocator());
// Use insert for lookup, so we can add missing values with a second lookup.
std::pair<ValueMap::iterator, bool> InsP =
Values.insert(std::make_pair(std::make_pair(RegIdx, ParentVNI->id),
ValueForcePair(VNI, false)));
// This was the first time (RegIdx, ParentVNI) was mapped.
// Keep it as a simple def without any liveness.
if (InsP.second)
return VNI;
// If the previous value was a simple mapping, add liveness for it now.
if (VNInfo *OldVNI = InsP.first->second.getPointer()) {
SlotIndex Def = OldVNI->def;
LI->addRange(LiveRange(Def, Def.getNextSlot(), OldVNI));
// No longer a simple mapping. Switch to a complex, non-forced mapping.
InsP.first->second = ValueForcePair();
}
// This is a complex mapping, add liveness for VNI
SlotIndex Def = VNI->def;
LI->addRange(LiveRange(Def, Def.getNextSlot(), VNI));
return VNI;
}
/// When adding a new instruction to liveness, the newly added definition
/// will start a new live segment. This may happen at a position that falls
/// within an existing live segment. In such case that live segment needs to
/// be truncated to make room for the new segment. Ultimately, the truncation
/// will occur at the last use, but for now the segment can be terminated
/// right at the place where the new segment will start. The segments will be
/// shrunk-to-uses later.
void HexagonExpandCondsets::terminateSegment(LiveInterval::iterator LT,
SlotIndex S, LiveInterval &LI) {
// Terminate the live segment pointed to by LT within a live interval LI.
if (LT == LI.end())
return;
VNInfo *OldVN = LT->valno;
SlotIndex EX = LT->end;
LT->end = S;
// If LT does not end at a block boundary, the termination is done.
if (!EX.isBlock())
return;
// If LT ended at a block boundary, it's possible that its value number
// is picked up at the beginning other blocks. Create a new value number
// and change such blocks to use it instead.
VNInfo *NewVN = 0;
for (LiveInterval::iterator I = LI.begin(), E = LI.end(); I != E; ++I) {
if (!I->start.isBlock() || I->valno != OldVN)
continue;
// Generate on-demand a new value number that is defined by the
// block beginning (i.e. -phi).
if (!NewVN)
NewVN = LI.getNextValue(I->start, LIS->getVNInfoAllocator());
I->valno = NewVN;
}
}
/// insertSpill - Insert a spill of NewLI.reg after MI.
void InlineSpiller::insertSpill(LiveInterval &NewLI, const LiveInterval &OldLI,
SlotIndex Idx, MachineBasicBlock::iterator MI) {
MachineBasicBlock &MBB = *MI->getParent();
TII.storeRegToStackSlot(MBB, ++MI, NewLI.reg, true, StackSlot,
MRI.getRegClass(NewLI.reg), &TRI);
--MI; // Point to store instruction.
SlotIndex StoreIdx = LIS.InsertMachineInstrInMaps(MI).getRegSlot();
DEBUG(dbgs() << "\tspilled: " << StoreIdx << '\t' << *MI);
VNInfo *StoreVNI = NewLI.getNextValue(Idx, LIS.getVNInfoAllocator());
NewLI.addRange(LiveRange(Idx, StoreIdx, StoreVNI));
++NumSpills;
}
/// insertSpill - Insert a spill of NewLI.reg after MI.
void InlineSpiller::insertSpill(LiveInterval &NewLI,
MachineBasicBlock::iterator MI) {
MachineBasicBlock &MBB = *MI->getParent();
SlotIndex Idx = lis_.getInstructionIndex(MI).getDefIndex();
tii_.storeRegToStackSlot(MBB, ++MI, NewLI.reg, true, stackSlot_, rc_, &tri_);
--MI; // Point to store instruction.
SlotIndex StoreIdx = lis_.InsertMachineInstrInMaps(MI).getDefIndex();
vrm_.addSpillSlotUse(stackSlot_, MI);
DEBUG(dbgs() << "\tspilled: " << StoreIdx << '\t' << *MI);
VNInfo *StoreVNI = NewLI.getNextValue(Idx, 0, true,
lis_.getVNInfoAllocator());
NewLI.addRange(LiveRange(Idx, StoreIdx, StoreVNI));
}
/// insertReload - Insert a reload of NewLI.reg before MI.
void InlineSpiller::insertReload(LiveInterval &NewLI,
MachineBasicBlock::iterator MI) {
MachineBasicBlock &MBB = *MI->getParent();
SlotIndex Idx = lis_.getInstructionIndex(MI).getDefIndex();
tii_.loadRegFromStackSlot(MBB, MI, NewLI.reg, stackSlot_, rc_, &tri_);
--MI; // Point to load instruction.
SlotIndex LoadIdx = lis_.InsertMachineInstrInMaps(MI).getDefIndex();
vrm_.addSpillSlotUse(stackSlot_, MI);
DEBUG(dbgs() << "\treload: " << LoadIdx << '\t' << *MI);
VNInfo *LoadVNI = NewLI.getNextValue(LoadIdx, 0, true,
lis_.getVNInfoAllocator());
NewLI.addRange(LiveRange(LoadIdx, Idx, LoadVNI));
}
/// insertReload - Insert a reload of NewLI.reg before MI.
void InlineSpiller::insertReload(LiveInterval &NewLI,
SlotIndex Idx,
MachineBasicBlock::iterator MI) {
MachineBasicBlock &MBB = *MI->getParent();
TII.loadRegFromStackSlot(MBB, MI, NewLI.reg, StackSlot,
MRI.getRegClass(NewLI.reg), &TRI);
--MI; // Point to load instruction.
SlotIndex LoadIdx = LIS.InsertMachineInstrInMaps(MI).getRegSlot();
// Some (out-of-tree) targets have EC reload instructions.
if (MachineOperand *MO = MI->findRegisterDefOperand(NewLI.reg))
if (MO->isEarlyClobber())
LoadIdx = LoadIdx.getRegSlot(true);
DEBUG(dbgs() << "\treload: " << LoadIdx << '\t' << *MI);
VNInfo *LoadVNI = NewLI.getNextValue(LoadIdx, LIS.getVNInfoAllocator());
NewLI.addRange(LiveRange(LoadIdx, Idx, LoadVNI));
++NumReloads;
}
bool StackColoring::runOnMachineFunction(MachineFunction &Func) {
DEBUG(dbgs() << "********** Stack Coloring **********\n"
<< "********** Function: "
<< ((const Value*)Func.getFunction())->getName() << '\n');
MF = &Func;
MFI = MF->getFrameInfo();
Indexes = &getAnalysis<SlotIndexes>();
BlockLiveness.clear();
BasicBlocks.clear();
BasicBlockNumbering.clear();
Markers.clear();
Intervals.clear();
VNInfoAllocator.Reset();
unsigned NumSlots = MFI->getObjectIndexEnd();
// If there are no stack slots then there are no markers to remove.
if (!NumSlots)
return false;
SmallVector<int, 8> SortedSlots;
SortedSlots.reserve(NumSlots);
Intervals.reserve(NumSlots);
unsigned NumMarkers = collectMarkers(NumSlots);
unsigned TotalSize = 0;
DEBUG(dbgs()<<"Found "<<NumMarkers<<" markers and "<<NumSlots<<" slots\n");
DEBUG(dbgs()<<"Slot structure:\n");
for (int i=0; i < MFI->getObjectIndexEnd(); ++i) {
DEBUG(dbgs()<<"Slot #"<<i<<" - "<<MFI->getObjectSize(i)<<" bytes.\n");
TotalSize += MFI->getObjectSize(i);
}
DEBUG(dbgs()<<"Total Stack size: "<<TotalSize<<" bytes\n\n");
// Don't continue because there are not enough lifetime markers, or the
// stack is too small, or we are told not to optimize the slots.
if (NumMarkers < 2 || TotalSize < 16 || DisableColoring) {
DEBUG(dbgs()<<"Will not try to merge slots.\n");
return removeAllMarkers();
}
for (unsigned i=0; i < NumSlots; ++i) {
LiveInterval *LI = new LiveInterval(i, 0);
Intervals.push_back(LI);
LI->getNextValue(Indexes->getZeroIndex(), VNInfoAllocator);
SortedSlots.push_back(i);
}
// Calculate the liveness of each block.
calculateLocalLiveness();
// Propagate the liveness information.
calculateLiveIntervals(NumSlots);
// Search for allocas which are used outside of the declared lifetime
// markers.
if (ProtectFromEscapedAllocas)
removeInvalidSlotRanges();
// Maps old slots to new slots.
DenseMap<int, int> SlotRemap;
unsigned RemovedSlots = 0;
unsigned ReducedSize = 0;
// Do not bother looking at empty intervals.
for (unsigned I = 0; I < NumSlots; ++I) {
if (Intervals[SortedSlots[I]]->empty())
SortedSlots[I] = -1;
}
// This is a simple greedy algorithm for merging allocas. First, sort the
// slots, placing the largest slots first. Next, perform an n^2 scan and look
// for disjoint slots. When you find disjoint slots, merge the samller one
// into the bigger one and update the live interval. Remove the small alloca
// and continue.
// Sort the slots according to their size. Place unused slots at the end.
// Use stable sort to guarantee deterministic code generation.
std::stable_sort(SortedSlots.begin(), SortedSlots.end(),
SlotSizeSorter(MFI));
bool Changed = true;
while (Changed) {
Changed = false;
for (unsigned I = 0; I < NumSlots; ++I) {
if (SortedSlots[I] == -1)
continue;
for (unsigned J=I+1; J < NumSlots; ++J) {
if (SortedSlots[J] == -1)
continue;
int FirstSlot = SortedSlots[I];
int SecondSlot = SortedSlots[J];
LiveInterval *First = Intervals[FirstSlot];
LiveInterval *Second = Intervals[SecondSlot];
assert (!First->empty() && !Second->empty() && "Found an empty range");
// Merge disjoint slots.
if (!First->overlaps(*Second)) {
Changed = true;
First->MergeSegmentsInAsValue(*Second, First->getValNumInfo(0));
SlotRemap[SecondSlot] = FirstSlot;
SortedSlots[J] = -1;
DEBUG(dbgs()<<"Merging #"<<FirstSlot<<" and slots #"<<
SecondSlot<<" together.\n");
unsigned MaxAlignment = std::max(MFI->getObjectAlignment(FirstSlot),
MFI->getObjectAlignment(SecondSlot));
assert(MFI->getObjectSize(FirstSlot) >=
MFI->getObjectSize(SecondSlot) &&
"Merging a small object into a larger one");
RemovedSlots+=1;
ReducedSize += MFI->getObjectSize(SecondSlot);
MFI->setObjectAlignment(FirstSlot, MaxAlignment);
MFI->RemoveStackObject(SecondSlot);
}
}
}
}// While changed.
// Record statistics.
StackSpaceSaved += ReducedSize;
StackSlotMerged += RemovedSlots;
DEBUG(dbgs()<<"Merge "<<RemovedSlots<<" slots. Saved "<<
ReducedSize<<" bytes\n");
// Scan the entire function and update all machine operands that use frame
// indices to use the remapped frame index.
expungeSlotMap(SlotRemap, NumSlots);
remapInstructions(SlotRemap);
// Release the intervals.
for (unsigned I = 0; I < NumSlots; ++I) {
delete Intervals[I];
}
return removeAllMarkers();
}
void LiveIntervals::handleVirtualRegisterDef(MachineBasicBlock *mbb,
MachineBasicBlock::iterator mi,
SlotIndex MIIdx,
MachineOperand& MO,
unsigned MOIdx,
LiveInterval &interval) {
DEBUG(dbgs() << "\t\tregister: " << PrintReg(interval.reg, tri_));
// Virtual registers may be defined multiple times (due to phi
// elimination and 2-addr elimination). Much of what we do only has to be
// done once for the vreg. We use an empty interval to detect the first
// time we see a vreg.
LiveVariables::VarInfo& vi = lv_->getVarInfo(interval.reg);
if (interval.empty()) {
// Get the Idx of the defining instructions.
SlotIndex defIndex = MIIdx.getRegSlot(MO.isEarlyClobber());
// Make sure the first definition is not a partial redefinition. Add an
// <imp-def> of the full register.
// FIXME: LiveIntervals shouldn't modify the code like this. Whoever
// created the machine instruction should annotate it with <undef> flags
// as needed. Then we can simply assert here. The REG_SEQUENCE lowering
// is the main suspect.
if (MO.getSubReg()) {
mi->addRegisterDefined(interval.reg);
// Mark all defs of interval.reg on this instruction as reading <undef>.
for (unsigned i = MOIdx, e = mi->getNumOperands(); i != e; ++i) {
MachineOperand &MO2 = mi->getOperand(i);
if (MO2.isReg() && MO2.getReg() == interval.reg && MO2.getSubReg())
MO2.setIsUndef();
}
}
MachineInstr *CopyMI = NULL;
if (mi->isCopyLike()) {
CopyMI = mi;
}
VNInfo *ValNo = interval.getNextValue(defIndex, CopyMI, VNInfoAllocator);
assert(ValNo->id == 0 && "First value in interval is not 0?");
// Loop over all of the blocks that the vreg is defined in. There are
// two cases we have to handle here. The most common case is a vreg
// whose lifetime is contained within a basic block. In this case there
// will be a single kill, in MBB, which comes after the definition.
if (vi.Kills.size() == 1 && vi.Kills[0]->getParent() == mbb) {
// FIXME: what about dead vars?
SlotIndex killIdx;
if (vi.Kills[0] != mi)
killIdx = getInstructionIndex(vi.Kills[0]).getRegSlot();
else
killIdx = defIndex.getDeadSlot();
// If the kill happens after the definition, we have an intra-block
// live range.
if (killIdx > defIndex) {
assert(vi.AliveBlocks.empty() &&
"Shouldn't be alive across any blocks!");
LiveRange LR(defIndex, killIdx, ValNo);
interval.addRange(LR);
DEBUG(dbgs() << " +" << LR << "\n");
return;
}
}
// The other case we handle is when a virtual register lives to the end
// of the defining block, potentially live across some blocks, then is
// live into some number of blocks, but gets killed. Start by adding a
// range that goes from this definition to the end of the defining block.
LiveRange NewLR(defIndex, getMBBEndIdx(mbb), ValNo);
DEBUG(dbgs() << " +" << NewLR);
interval.addRange(NewLR);
bool PHIJoin = lv_->isPHIJoin(interval.reg);
if (PHIJoin) {
// A phi join register is killed at the end of the MBB and revived as a new
// valno in the killing blocks.
assert(vi.AliveBlocks.empty() && "Phi join can't pass through blocks");
DEBUG(dbgs() << " phi-join");
ValNo->setHasPHIKill(true);
} else {
// Iterate over all of the blocks that the variable is completely
// live in, adding [insrtIndex(begin), instrIndex(end)+4) to the
// live interval.
for (SparseBitVector<>::iterator I = vi.AliveBlocks.begin(),
E = vi.AliveBlocks.end(); I != E; ++I) {
MachineBasicBlock *aliveBlock = mf_->getBlockNumbered(*I);
LiveRange LR(getMBBStartIdx(aliveBlock), getMBBEndIdx(aliveBlock), ValNo);
interval.addRange(LR);
DEBUG(dbgs() << " +" << LR);
}
}
// Finally, this virtual register is live from the start of any killing
// block to the 'use' slot of the killing instruction.
for (unsigned i = 0, e = vi.Kills.size(); i != e; ++i) {
MachineInstr *Kill = vi.Kills[i];
SlotIndex Start = getMBBStartIdx(Kill->getParent());
SlotIndex killIdx = getInstructionIndex(Kill).getRegSlot();
// Create interval with one of a NEW value number. Note that this value
// number isn't actually defined by an instruction, weird huh? :)
if (PHIJoin) {
assert(getInstructionFromIndex(Start) == 0 &&
"PHI def index points at actual instruction.");
ValNo = interval.getNextValue(Start, 0, VNInfoAllocator);
ValNo->setIsPHIDef(true);
}
LiveRange LR(Start, killIdx, ValNo);
interval.addRange(LR);
DEBUG(dbgs() << " +" << LR);
}
} else {
if (MultipleDefsBySameMI(*mi, MOIdx))
// Multiple defs of the same virtual register by the same instruction.
// e.g. %reg1031:5<def>, %reg1031:6<def> = VLD1q16 %reg1024<kill>, ...
// This is likely due to elimination of REG_SEQUENCE instructions. Return
// here since there is nothing to do.
return;
// If this is the second time we see a virtual register definition, it
// must be due to phi elimination or two addr elimination. If this is
// the result of two address elimination, then the vreg is one of the
// def-and-use register operand.
// It may also be partial redef like this:
// 80 %reg1041:6<def> = VSHRNv4i16 %reg1034<kill>, 12, pred:14, pred:%reg0
// 120 %reg1041:5<def> = VSHRNv4i16 %reg1039<kill>, 12, pred:14, pred:%reg0
bool PartReDef = isPartialRedef(MIIdx, MO, interval);
if (PartReDef || mi->isRegTiedToUseOperand(MOIdx)) {
// If this is a two-address definition, then we have already processed
// the live range. The only problem is that we didn't realize there
// are actually two values in the live interval. Because of this we
// need to take the LiveRegion that defines this register and split it
// into two values.
SlotIndex RedefIndex = MIIdx.getRegSlot(MO.isEarlyClobber());
const LiveRange *OldLR =
interval.getLiveRangeContaining(RedefIndex.getRegSlot(true));
VNInfo *OldValNo = OldLR->valno;
SlotIndex DefIndex = OldValNo->def.getRegSlot();
// Delete the previous value, which should be short and continuous,
// because the 2-addr copy must be in the same MBB as the redef.
interval.removeRange(DefIndex, RedefIndex);
// The new value number (#1) is defined by the instruction we claimed
// defined value #0.
VNInfo *ValNo = interval.createValueCopy(OldValNo, VNInfoAllocator);
// Value#0 is now defined by the 2-addr instruction.
OldValNo->def = RedefIndex;
OldValNo->setCopy(0);
// A re-def may be a copy. e.g. %reg1030:6<def> = VMOVD %reg1026, ...
if (PartReDef && mi->isCopyLike())
OldValNo->setCopy(&*mi);
// Add the new live interval which replaces the range for the input copy.
LiveRange LR(DefIndex, RedefIndex, ValNo);
DEBUG(dbgs() << " replace range with " << LR);
interval.addRange(LR);
// If this redefinition is dead, we need to add a dummy unit live
// range covering the def slot.
if (MO.isDead())
interval.addRange(LiveRange(RedefIndex, RedefIndex.getDeadSlot(),
OldValNo));
DEBUG({
dbgs() << " RESULT: ";
interval.print(dbgs(), tri_);
});
} else if (lv_->isPHIJoin(interval.reg)) {