C++ LiveInterval::find方法代码示例

void StackColoring::removeInvalidSlotRanges() {
  MachineFunction::const_iterator BB, BBE;
  MachineBasicBlock::const_iterator I, IE;
  for (BB = MF->begin(), BBE = MF->end(); BB != BBE; ++BB)
    for (I = BB->begin(), IE = BB->end(); I != IE; ++I) {

      if (I->getOpcode() == TargetOpcode::LIFETIME_START ||
          I->getOpcode() == TargetOpcode::LIFETIME_END || I->isDebugValue())
        continue;

      // Some intervals are suspicious! In some cases we find address
      // calculations outside of the lifetime zone, but not actual memory
      // read or write. Memory accesses outside of the lifetime zone are a clear
      // violation, but address calculations are okay. This can happen when
      // GEPs are hoisted outside of the lifetime zone.
      // So, in here we only check instructions which can read or write memory.
      if (!I->mayLoad() && !I->mayStore())
        continue;

      // Check all of the machine operands.
      for (unsigned i = 0 ; i <  I->getNumOperands(); ++i) {
        const MachineOperand &MO = I->getOperand(i);

        if (!MO.isFI())
          continue;

        int Slot = MO.getIndex();

        if (Slot<0)
          continue;

        if (Intervals[Slot]->empty())
          continue;

        // Check that the used slot is inside the calculated lifetime range.
        // If it is not, warn about it and invalidate the range.
        LiveInterval *Interval = Intervals[Slot];
        SlotIndex Index = Indexes->getInstructionIndex(I);
        if (Interval->find(Index) == Interval->end()) {
          Intervals[Slot]->clear();
          DEBUG(dbgs()<<"Invalidating range #"<<Slot<<"\n");
          EscapedAllocas++;
        }
      }
    }
}

void StackColoring::removeInvalidSlotRanges() {
  for (MachineBasicBlock &BB : *MF)
    for (MachineInstr &I : BB) {
      if (I.getOpcode() == TargetOpcode::LIFETIME_START ||
          I.getOpcode() == TargetOpcode::LIFETIME_END || I.isDebugValue())
        continue;

      // Some intervals are suspicious! In some cases we find address
      // calculations outside of the lifetime zone, but not actual memory
      // read or write. Memory accesses outside of the lifetime zone are a clear
      // violation, but address calculations are okay. This can happen when
      // GEPs are hoisted outside of the lifetime zone.
      // So, in here we only check instructions which can read or write memory.
      if (!I.mayLoad() && !I.mayStore())
        continue;

      // Check all of the machine operands.
      for (const MachineOperand &MO : I.operands()) {
        if (!MO.isFI())
          continue;

        int Slot = MO.getIndex();

        if (Slot<0)
          continue;

        if (Intervals[Slot]->empty())
          continue;

        // Check that the used slot is inside the calculated lifetime range.
        // If it is not, warn about it and invalidate the range.
        LiveInterval *Interval = &*Intervals[Slot];
        SlotIndex Index = Indexes->getInstructionIndex(I);
        if (Interval->find(Index) == Interval->end()) {
          Interval->clear();
          DEBUG(dbgs()<<"Invalidating range #"<<Slot<<"\n");
          EscapedAllocas++;
        }
      }
    }
}

bool LiveInterval::overlaps(const LiveInterval &Other,
                            const CoalescerPair &CP,
                            const SlotIndexes &Indexes) const {
  assert(!empty() && "empty interval");
  if (Other.empty())
    return false;

  // Use binary searches to find initial positions.
  const_iterator I = find(Other.beginIndex());
  const_iterator IE = end();
  if (I == IE)
    return false;
  const_iterator J = Other.find(I->start);
  const_iterator JE = Other.end();
  if (J == JE)
    return false;

  for (;;) {
    // J has just been advanced to satisfy:
    assert(J->end >= I->start);
    // Check for an overlap.
    if (J->start < I->end) {
      // I and J are overlapping. Find the later start.
      SlotIndex Def = std::max(I->start, J->start);
      // Allow the overlap if Def is a coalescable copy.
      if (Def.isBlock() ||
          !CP.isCoalescable(Indexes.getInstructionFromIndex(Def)))
        return true;
    }
    // Advance the iterator that ends first to check for more overlaps.
    if (J->end > I->end) {
      std::swap(I, J);
      std::swap(IE, JE);
    }
    // Advance J until J->end >= I->start.
    do
      if (++J == JE)
        return false;
    while (J->end < I->start);
  }
}

//.........这里部分代码省略.........

  // Keep a list of *allocas* which need to be remapped.
  DenseMap<const AllocaInst*, const AllocaInst*> Allocas;
  for (DenseMap<int, int>::const_iterator it = SlotRemap.begin(),
       e = SlotRemap.end(); it != e; ++it) {
    const AllocaInst *From = MFI->getObjectAllocation(it->first);
    const AllocaInst *To = MFI->getObjectAllocation(it->second);
    assert(To && From && "Invalid allocation object");
    Allocas[From] = To;
  }

  // Remap all instructions to the new stack slots.
  MachineFunction::iterator BB, BBE;
  MachineBasicBlock::iterator I, IE;
  for (BB = MF->begin(), BBE = MF->end(); BB != BBE; ++BB)
    for (I = BB->begin(), IE = BB->end(); I != IE; ++I) {

      // Skip lifetime markers. We'll remove them soon.
      if (I->getOpcode() == TargetOpcode::LIFETIME_START ||
          I->getOpcode() == TargetOpcode::LIFETIME_END)
        continue;

      // Update the MachineMemOperand to use the new alloca.
      for (MachineInstr::mmo_iterator MM = I->memoperands_begin(),
           E = I->memoperands_end(); MM != E; ++MM) {
        MachineMemOperand *MMO = *MM;

        const Value *V = MMO->getValue();

        if (!V)
          continue;

        const PseudoSourceValue *PSV = dyn_cast<const PseudoSourceValue>(V);
        if (PSV && PSV->isConstant(MFI))
          continue;

        // Climb up and find the original alloca.
        V = GetUnderlyingObject(V);
        // If we did not find one, or if the one that we found is not in our
        // map, then move on.
        if (!V || !isa<AllocaInst>(V)) {
          // Clear mem operand since we don't know for sure that it doesn't
          // alias a merged alloca.
          MMO->setValue(0);
          continue;
        }
        const AllocaInst *AI= cast<AllocaInst>(V);
        if (!Allocas.count(AI))
          continue;

        MMO->setValue(Allocas[AI]);
        FixedMemOp++;
      }

      // Update all of the machine instruction operands.
      for (unsigned i = 0 ; i <  I->getNumOperands(); ++i) {
        MachineOperand &MO = I->getOperand(i);

        if (!MO.isFI())
          continue;
        int FromSlot = MO.getIndex();

        // Don't touch arguments.
        if (FromSlot<0)
          continue;

        // Only look at mapped slots.
        if (!SlotRemap.count(FromSlot))
          continue;

        // In a debug build, check that the instruction that we are modifying is
        // inside the expected live range. If the instruction is not inside
        // the calculated range then it means that the alloca usage moved
        // outside of the lifetime markers, or that the user has a bug.
        // NOTE: Alloca address calculations which happen outside the lifetime
        // zone are are okay, despite the fact that we don't have a good way
        // for validating all of the usages of the calculation.
#ifndef NDEBUG
        bool TouchesMemory = I->mayLoad() || I->mayStore();
        // If we *don't* protect the user from escaped allocas, don't bother
        // validating the instructions.
        if (!I->isDebugValue() && TouchesMemory && ProtectFromEscapedAllocas) {
          SlotIndex Index = Indexes->getInstructionIndex(I);
          LiveInterval *Interval = Intervals[FromSlot];
          assert(Interval->find(Index) != Interval->end() &&
                 "Found instruction usage outside of live range.");
        }
#endif

        // Fix the machine instructions.
        int ToSlot = SlotRemap[FromSlot];
        MO.setIndex(ToSlot);
        FixedInstr++;
      }
    }

  DEBUG(dbgs()<<"Fixed "<<FixedMemOp<<" machine memory operands.\n");
  DEBUG(dbgs()<<"Fixed "<<FixedDbg<<" debug locations.\n");
  DEBUG(dbgs()<<"Fixed "<<FixedInstr<<" machine instructions.\n");
}

void LiveIntervals::addKillFlags(const VirtRegMap *VRM) {
  // Keep track of regunit ranges.
  SmallVector<std::pair<LiveInterval*, LiveInterval::iterator>, 8> RU;

  for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) {
    unsigned Reg = TargetRegisterInfo::index2VirtReg(i);
    if (MRI->reg_nodbg_empty(Reg))
      continue;
    LiveInterval *LI = &getInterval(Reg);
    if (LI->empty())
      continue;

    // Find the regunit intervals for the assigned register. They may overlap
    // the virtual register live range, cancelling any kills.
    RU.clear();
    for (MCRegUnitIterator Units(VRM->getPhys(Reg), TRI); Units.isValid();
         ++Units) {
      LiveInterval *RUInt = &getRegUnit(*Units);
      if (RUInt->empty())
        continue;
      RU.push_back(std::make_pair(RUInt, RUInt->find(LI->begin()->end)));
    }

    // Every instruction that kills Reg corresponds to a live range end point.
    for (LiveInterval::iterator RI = LI->begin(), RE = LI->end(); RI != RE;
         ++RI) {
      // A block index indicates an MBB edge.
      if (RI->end.isBlock())
        continue;
      MachineInstr *MI = getInstructionFromIndex(RI->end);
      if (!MI)
        continue;

      // Check if any of the regunits are live beyond the end of RI. That could
      // happen when a physreg is defined as a copy of a virtreg:
      //
      //   %EAX = COPY %vreg5
      //   FOO %vreg5         <--- MI, cancel kill because %EAX is live.
      //   BAR %EAX<kill>
      //
      // There should be no kill flag on FOO when %vreg5 is rewritten as %EAX.
      bool CancelKill = false;
      for (unsigned u = 0, e = RU.size(); u != e; ++u) {
        LiveInterval *RInt = RU[u].first;
        LiveInterval::iterator &I = RU[u].second;
        if (I == RInt->end())
          continue;
        I = RInt->advanceTo(I, RI->end);
        if (I == RInt->end() || I->start >= RI->end)
          continue;
        // I is overlapping RI.
        CancelKill = true;
        break;
      }
      if (CancelKill)
        MI->clearRegisterKills(Reg, NULL);
      else
        MI->addRegisterKilled(Reg, NULL);
    }
  }
}

void StackColoring::remapInstructions(DenseMap<int, int> &SlotRemap) {
  unsigned FixedInstr = 0;
  unsigned FixedMemOp = 0;
  unsigned FixedDbg = 0;
  MachineModuleInfo *MMI = &MF->getMMI();

  // Remap debug information that refers to stack slots.
  MachineModuleInfo::VariableDbgInfoMapTy &VMap = MMI->getVariableDbgInfo();
  for (MachineModuleInfo::VariableDbgInfoMapTy::iterator VI = VMap.begin(),
       VE = VMap.end(); VI != VE; ++VI) {
    const MDNode *Var = VI->first;
    if (!Var) continue;
    std::pair<unsigned, DebugLoc> &VP = VI->second;
    if (SlotRemap.count(VP.first)) {
      DEBUG(dbgs()<<"Remapping debug info for ["<<Var->getName()<<"].\n");
      VP.first = SlotRemap[VP.first];
      FixedDbg++;
    }
  }

  // Keep a list of *allocas* which need to be remapped.
  DenseMap<const Value*, const Value*> Allocas;
  for (DenseMap<int, int>::iterator it = SlotRemap.begin(),
       e = SlotRemap.end(); it != e; ++it) {
    const Value *From = MFI->getObjectAllocation(it->first);
    const Value *To = MFI->getObjectAllocation(it->second);
    assert(To && From && "Invalid allocation object");
    Allocas[From] = To;
  }

  // Remap all instructions to the new stack slots.
  MachineFunction::iterator BB, BBE;
  MachineBasicBlock::iterator I, IE;
  for (BB = MF->begin(), BBE = MF->end(); BB != BBE; ++BB)
    for (I = BB->begin(), IE = BB->end(); I != IE; ++I) {

      // Skip lifetime markers. We'll remove them soon.
      if (I->getOpcode() == TargetOpcode::LIFETIME_START ||
          I->getOpcode() == TargetOpcode::LIFETIME_END)
        continue;

      // Update the MachineMemOperand to use the new alloca.
      for (MachineInstr::mmo_iterator MM = I->memoperands_begin(),
           E = I->memoperands_end(); MM != E; ++MM) {
        MachineMemOperand *MMO = *MM;

        const Value *V = MMO->getValue();

        if (!V)
          continue;

        // Climb up and find the original alloca.
        V = GetUnderlyingObject(V);
        // If we did not find one, or if the one that we found is not in our
        // map, then move on.
        if (!V || !Allocas.count(V))
          continue;

        MMO->setValue(Allocas[V]);
        FixedMemOp++;
      }

      // Update all of the machine instruction operands.
      for (unsigned i = 0 ; i <  I->getNumOperands(); ++i) {
        MachineOperand &MO = I->getOperand(i);

        if (!MO.isFI())
          continue;
        int FromSlot = MO.getIndex();

        // Don't touch arguments.
        if (FromSlot<0)
          continue;

        // Only look at mapped slots.
        if (!SlotRemap.count(FromSlot))
          continue;

        // In a debug build, check that the instruction that we are modifying is
        // inside the expected live range. If the instruction is not inside
        // the calculated range then it means that the alloca usage moved
        // outside of the lifetime markers.
#ifndef NDEBUG
        SlotIndex Index = Indexes->getInstructionIndex(I);
        LiveInterval* Interval = Intervals[FromSlot];
        assert(Interval->find(Index) != Interval->end() &&
               "Found instruction usage outside of live range.");
#endif

        // Fix the machine instructions.
        int ToSlot = SlotRemap[FromSlot];
        MO.setIndex(ToSlot);
        FixedInstr++;
      }
    }

  DEBUG(dbgs()<<"Fixed "<<FixedMemOp<<" machine memory operands.\n");
  DEBUG(dbgs()<<"Fixed "<<FixedDbg<<" debug locations.\n");
  DEBUG(dbgs()<<"Fixed "<<FixedInstr<<" machine instructions.\n");
}