-/// disallowClobberPhysRegOnly - Unset the CanClobber bit of the specified
-/// stackslot register. The register is still available but is no longer
-/// allowed to be modifed.
-void AvailableSpills::disallowClobberPhysRegOnly(unsigned PhysReg) {
- std::multimap<unsigned, int>::iterator I =
- PhysRegsAvailable.lower_bound(PhysReg);
- while (I != PhysRegsAvailable.end() && I->first == PhysReg) {
- int SlotOrReMat = I->second;
- I++;
- assert((SpillSlotsOrReMatsAvailable[SlotOrReMat] >> 1) == PhysReg &&
- "Bidirectional map mismatch!");
- SpillSlotsOrReMatsAvailable[SlotOrReMat] &= ~1;
- DOUT << "PhysReg " << TRI->getName(PhysReg)
- << " copied, it is available for use but can no longer be modified\n";
- }
-}
-
-/// disallowClobberPhysReg - Unset the CanClobber bit of the specified
-/// stackslot register and its aliases. The register and its aliases may
-/// still available but is no longer allowed to be modifed.
-void AvailableSpills::disallowClobberPhysReg(unsigned PhysReg) {
- for (const unsigned *AS = TRI->getAliasSet(PhysReg); *AS; ++AS)
- disallowClobberPhysRegOnly(*AS);
- disallowClobberPhysRegOnly(PhysReg);
-}
-
-/// ClobberPhysRegOnly - This is called when the specified physreg changes
-/// value. We use this to invalidate any info about stuff we thing lives in it.
-void AvailableSpills::ClobberPhysRegOnly(unsigned PhysReg) {
- std::multimap<unsigned, int>::iterator I =
- PhysRegsAvailable.lower_bound(PhysReg);
- while (I != PhysRegsAvailable.end() && I->first == PhysReg) {
- int SlotOrReMat = I->second;
- PhysRegsAvailable.erase(I++);
- assert((SpillSlotsOrReMatsAvailable[SlotOrReMat] >> 1) == PhysReg &&
- "Bidirectional map mismatch!");
- SpillSlotsOrReMatsAvailable.erase(SlotOrReMat);
- DOUT << "PhysReg " << TRI->getName(PhysReg)
- << " clobbered, invalidating ";
- if (SlotOrReMat > VirtRegMap::MAX_STACK_SLOT)
- DOUT << "RM#" << SlotOrReMat-VirtRegMap::MAX_STACK_SLOT-1 << "\n";
- else
- DOUT << "SS#" << SlotOrReMat << "\n";
- }
-}
-
-/// ClobberPhysReg - This is called when the specified physreg changes
-/// value. We use this to invalidate any info about stuff we thing lives in
-/// it and any of its aliases.
-void AvailableSpills::ClobberPhysReg(unsigned PhysReg) {
- for (const unsigned *AS = TRI->getAliasSet(PhysReg); *AS; ++AS)
- ClobberPhysRegOnly(*AS);
- ClobberPhysRegOnly(PhysReg);
-}
-
-/// ModifyStackSlotOrReMat - This method is called when the value in a stack
-/// slot changes. This removes information about which register the previous
-/// value for this slot lives in (as the previous value is dead now).
-void AvailableSpills::ModifyStackSlotOrReMat(int SlotOrReMat) {
- std::map<int, unsigned>::iterator It =
- SpillSlotsOrReMatsAvailable.find(SlotOrReMat);
- if (It == SpillSlotsOrReMatsAvailable.end()) return;
- unsigned Reg = It->second >> 1;
- SpillSlotsOrReMatsAvailable.erase(It);
-
- // This register may hold the value of multiple stack slots, only remove this
- // stack slot from the set of values the register contains.
- std::multimap<unsigned, int>::iterator I = PhysRegsAvailable.lower_bound(Reg);
- for (; ; ++I) {
- assert(I != PhysRegsAvailable.end() && I->first == Reg &&
- "Map inverse broken!");
- if (I->second == SlotOrReMat) break;
- }
- PhysRegsAvailable.erase(I);
-}
-
-/// AddAvailableRegsToLiveIn - Availability information is being kept coming
-/// into the specified MBB. Add available physical registers as live-in's
-/// so register scavenger and post-allocation scheduler are happy.
-void AvailableSpills::AddAvailableRegsToLiveIn(MachineBasicBlock &MBB) {
- for (std::multimap<unsigned, int>::iterator
- I = PhysRegsAvailable.begin(), E = PhysRegsAvailable.end();
- I != E; ++I) {
- unsigned Reg = (*I).first;
- const TargetRegisterClass* RC = TRI->getPhysicalRegisterRegClass(Reg);
- // FIXME: A temporary workaround. We can't reuse available value if it's
- // not safe to move the def of the virtual register's class. e.g.
- // X86::RFP* register classes. Do not add it as a live-in.
- if (!TII->isSafeToMoveRegClassDefs(RC))
- continue;
- if (!MBB.isLiveIn(Reg))
- MBB.addLiveIn(Reg);
- }
-}
-
-/// findSinglePredSuccessor - Return via reference a vector of machine basic
-/// blocks each of which is a successor of the specified BB and has no other
-/// predecessor.
-static void findSinglePredSuccessor(MachineBasicBlock *MBB,
- SmallVectorImpl<MachineBasicBlock *> &Succs) {
- for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
- SE = MBB->succ_end(); SI != SE; ++SI) {
- MachineBasicBlock *SuccMBB = *SI;
- if (SuccMBB->pred_size() == 1)
- Succs.push_back(SuccMBB);
- }
-}
-
-namespace {
- /// LocalSpiller - This spiller does a simple pass over the machine basic
- /// block to attempt to keep spills in registers as much as possible for
- /// blocks that have low register pressure (the vreg may be spilled due to
- /// register pressure in other blocks).
- class VISIBILITY_HIDDEN LocalSpiller : public Spiller {
- MachineRegisterInfo *RegInfo;
- const TargetRegisterInfo *TRI;
- const TargetInstrInfo *TII;
- DenseMap<MachineInstr*, unsigned> DistanceMap;
- public:
- bool runOnMachineFunction(MachineFunction &MF, VirtRegMap &VRM) {
- RegInfo = &MF.getRegInfo();
- TRI = MF.getTarget().getRegisterInfo();
- TII = MF.getTarget().getInstrInfo();
- DOUT << "\n**** Local spiller rewriting function '"
- << MF.getFunction()->getName() << "':\n";
- DOUT << "**** Machine Instrs (NOTE! Does not include spills and reloads!)"
- " ****\n";
- DEBUG(MF.dump());
-
- // Spills - Keep track of which spilled values are available in physregs
- // so that we can choose to reuse the physregs instead of emitting
- // reloads. This is usually refreshed per basic block.
- AvailableSpills Spills(TRI, TII);
-
- // SingleEntrySuccs - Successor blocks which have a single predecessor.
- SmallVector<MachineBasicBlock*, 4> SinglePredSuccs;
- SmallPtrSet<MachineBasicBlock*,16> EarlyVisited;
-
- // Traverse the basic blocks depth first.
- MachineBasicBlock *Entry = MF.begin();
- SmallPtrSet<MachineBasicBlock*,16> Visited;
- for (df_ext_iterator<MachineBasicBlock*,
- SmallPtrSet<MachineBasicBlock*,16> >
- DFI = df_ext_begin(Entry, Visited), E = df_ext_end(Entry, Visited);
- DFI != E; ++DFI) {
- MachineBasicBlock *MBB = *DFI;
- if (!EarlyVisited.count(MBB))
- RewriteMBB(*MBB, VRM, Spills);
-
- // If this MBB is the only predecessor of a successor. Keep the
- // availability information and visit it next.
- do {
- // Keep visiting single predecessor successor as long as possible.
- SinglePredSuccs.clear();
- findSinglePredSuccessor(MBB, SinglePredSuccs);
- if (SinglePredSuccs.empty())
- MBB = 0;
- else {
- // FIXME: More than one successors, each of which has MBB has
- // the only predecessor.
- MBB = SinglePredSuccs[0];
- if (!Visited.count(MBB) && EarlyVisited.insert(MBB)) {
- Spills.AddAvailableRegsToLiveIn(*MBB);
- RewriteMBB(*MBB, VRM, Spills);
- }
- }
- } while (MBB);
-
- // Clear the availability info.
- Spills.clear();
- }
-
- DOUT << "**** Post Machine Instrs ****\n";
- DEBUG(MF.dump());
-
- // Mark unused spill slots.
- MachineFrameInfo *MFI = MF.getFrameInfo();
- int SS = VRM.getLowSpillSlot();
- if (SS != VirtRegMap::NO_STACK_SLOT)
- for (int e = VRM.getHighSpillSlot(); SS <= e; ++SS)
- if (!VRM.isSpillSlotUsed(SS)) {
- MFI->RemoveStackObject(SS);
- ++NumDSS;
- }
-
- return true;
- }
- private:
- void TransferDeadness(MachineBasicBlock *MBB, unsigned CurDist,
- unsigned Reg, BitVector &RegKills,
- std::vector<MachineOperand*> &KillOps);
- bool PrepForUnfoldOpti(MachineBasicBlock &MBB,
- MachineBasicBlock::iterator &MII,
- std::vector<MachineInstr*> &MaybeDeadStores,
- AvailableSpills &Spills, BitVector &RegKills,
- std::vector<MachineOperand*> &KillOps,
- VirtRegMap &VRM);
- bool CommuteToFoldReload(MachineBasicBlock &MBB,
- MachineBasicBlock::iterator &MII,
- unsigned VirtReg, unsigned SrcReg, int SS,
- BitVector &RegKills,
- std::vector<MachineOperand*> &KillOps,
- const TargetRegisterInfo *TRI,
- VirtRegMap &VRM);
- void SpillRegToStackSlot(MachineBasicBlock &MBB,
- MachineBasicBlock::iterator &MII,
- int Idx, unsigned PhysReg, int StackSlot,
- const TargetRegisterClass *RC,
- bool isAvailable, MachineInstr *&LastStore,
- AvailableSpills &Spills,
- SmallSet<MachineInstr*, 4> &ReMatDefs,
- BitVector &RegKills,
- std::vector<MachineOperand*> &KillOps,
- VirtRegMap &VRM);
- void RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM,
- AvailableSpills &Spills);
- };
-}
-
-/// InvalidateKills - MI is going to be deleted. If any of its operands are
-/// marked kill, then invalidate the information.
-static void InvalidateKills(MachineInstr &MI, BitVector &RegKills,
- std::vector<MachineOperand*> &KillOps,
- SmallVector<unsigned, 2> *KillRegs = NULL) {
- for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
- MachineOperand &MO = MI.getOperand(i);
- if (!MO.isReg() || !MO.isUse() || !MO.isKill())
- continue;
- unsigned Reg = MO.getReg();
- if (TargetRegisterInfo::isVirtualRegister(Reg))
- continue;
- if (KillRegs)
- KillRegs->push_back(Reg);
- assert(Reg < KillOps.size());
- if (KillOps[Reg] == &MO) {
- RegKills.reset(Reg);
- KillOps[Reg] = NULL;
- }
- }
-}
-
-/// InvalidateKill - A MI that defines the specified register is being deleted,
-/// invalidate the register kill information.
-static void InvalidateKill(unsigned Reg, BitVector &RegKills,
- std::vector<MachineOperand*> &KillOps) {
- if (RegKills[Reg]) {
- KillOps[Reg]->setIsKill(false);
- KillOps[Reg] = NULL;
- RegKills.reset(Reg);
- }
-}
-
-/// InvalidateRegDef - If the def operand of the specified def MI is now dead
-/// (since it's spill instruction is removed), mark it isDead. Also checks if
-/// the def MI has other definition operands that are not dead. Returns it by
-/// reference.
-static bool InvalidateRegDef(MachineBasicBlock::iterator I,
- MachineInstr &NewDef, unsigned Reg,
- bool &HasLiveDef) {
- // Due to remat, it's possible this reg isn't being reused. That is,
- // the def of this reg (by prev MI) is now dead.
- MachineInstr *DefMI = I;
- MachineOperand *DefOp = NULL;
- for (unsigned i = 0, e = DefMI->getNumOperands(); i != e; ++i) {
- MachineOperand &MO = DefMI->getOperand(i);
- if (MO.isReg() && MO.isDef()) {
- if (MO.getReg() == Reg)
- DefOp = &MO;
- else if (!MO.isDead())
- HasLiveDef = true;
- }
- }
- if (!DefOp)
- return false;
-
- bool FoundUse = false, Done = false;
- MachineBasicBlock::iterator E = &NewDef;
- ++I; ++E;
- for (; !Done && I != E; ++I) {
- MachineInstr *NMI = I;
- for (unsigned j = 0, ee = NMI->getNumOperands(); j != ee; ++j) {
- MachineOperand &MO = NMI->getOperand(j);
- if (!MO.isReg() || MO.getReg() != Reg)
- continue;
- if (MO.isUse())
- FoundUse = true;
- Done = true; // Stop after scanning all the operands of this MI.
- }
- }
- if (!FoundUse) {
- // Def is dead!
- DefOp->setIsDead();
- return true;
- }
- return false;
-}
-
-/// UpdateKills - Track and update kill info. If a MI reads a register that is
-/// marked kill, then it must be due to register reuse. Transfer the kill info
-/// over.
-static void UpdateKills(MachineInstr &MI, BitVector &RegKills,
- std::vector<MachineOperand*> &KillOps,
- const TargetRegisterInfo* TRI) {
- const TargetInstrDesc &TID = MI.getDesc();
- for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
- MachineOperand &MO = MI.getOperand(i);
- if (!MO.isReg() || !MO.isUse())
- continue;
- unsigned Reg = MO.getReg();
- if (Reg == 0)
- continue;
-
- if (RegKills[Reg] && KillOps[Reg]->getParent() != &MI) {
- // That can't be right. Register is killed but not re-defined and it's
- // being reused. Let's fix that.
- KillOps[Reg]->setIsKill(false);
- KillOps[Reg] = NULL;
- RegKills.reset(Reg);
- if (i < TID.getNumOperands() &&
- TID.getOperandConstraint(i, TOI::TIED_TO) == -1)
- // Unless it's a two-address operand, this is the new kill.
- MO.setIsKill();
- }
- if (MO.isKill()) {
- RegKills.set(Reg);
- KillOps[Reg] = &MO;
- }
- }
-
- for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
- const MachineOperand &MO = MI.getOperand(i);
- if (!MO.isReg() || !MO.isDef())
- continue;
- unsigned Reg = MO.getReg();
- RegKills.reset(Reg);
- KillOps[Reg] = NULL;
- // It also defines (or partially define) aliases.
- for (const unsigned *AS = TRI->getAliasSet(Reg); *AS; ++AS) {
- RegKills.reset(*AS);
- KillOps[*AS] = NULL;
- }
- }
-}
-
-/// ReMaterialize - Re-materialize definition for Reg targetting DestReg.
-///
-static void ReMaterialize(MachineBasicBlock &MBB,
- MachineBasicBlock::iterator &MII,
- unsigned DestReg, unsigned Reg,
- const TargetInstrInfo *TII,
- const TargetRegisterInfo *TRI,
- VirtRegMap &VRM) {
- TII->reMaterialize(MBB, MII, DestReg, VRM.getReMaterializedMI(Reg));
- MachineInstr *NewMI = prior(MII);
- for (unsigned i = 0, e = NewMI->getNumOperands(); i != e; ++i) {
- MachineOperand &MO = NewMI->getOperand(i);
- if (!MO.isReg() || MO.getReg() == 0)