C++ locmap::iterator类代码示例

void UserValue::coalesceLocation(unsigned LocNo) {
  unsigned KeepLoc = 0;
  for (unsigned e = locations.size(); KeepLoc != e; ++KeepLoc) {
    if (KeepLoc == LocNo)
      continue;
    if (locations[KeepLoc].isIdenticalTo(locations[LocNo]))
      break;
  }
  // No matches.
  if (KeepLoc == locations.size())
    return;

  // Keep the smaller location, erase the larger one.
  unsigned EraseLoc = LocNo;
  if (KeepLoc > EraseLoc)
    std::swap(KeepLoc, EraseLoc);
  locations.erase(locations.begin() + EraseLoc);

  // Rewrite values.
  for (LocMap::iterator I = locInts.begin(); I.valid(); ++I) {
    unsigned v = I.value();
    if (v == EraseLoc)
      I.setValue(KeepLoc);      // Coalesce when possible.
    else if (v > EraseLoc)
      I.setValueUnchecked(v-1); // Avoid coalescing with untransformed values.
  }
}

void
UserValue::computeIntervals(MachineRegisterInfo &MRI,
                            LiveIntervals &LIS,
                            MachineDominatorTree &MDT) {
  SmallVector<std::pair<SlotIndex, unsigned>, 16> Defs;

  // Collect all defs to be extended (Skipping undefs).
  for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I)
    if (I.value() != ~0u)
      Defs.push_back(std::make_pair(I.start(), I.value()));

  // Extend all defs, and possibly add new ones along the way.
  for (unsigned i = 0; i != Defs.size(); ++i) {
    SlotIndex Idx = Defs[i].first;
    unsigned LocNo = Defs[i].second;
    const MachineOperand &Loc = locations[LocNo];

    // Register locations are constrained to where the register value is live.
    if (Loc.isReg() && LIS.hasInterval(Loc.getReg())) {
      LiveInterval *LI = &LIS.getInterval(Loc.getReg());
      const VNInfo *VNI = LI->getVNInfoAt(Idx);
      SmallVector<SlotIndex, 16> Kills;
      extendDef(Idx, LocNo, LI, VNI, &Kills, LIS, MDT);
      addDefsFromCopies(LI, LocNo, Kills, Defs, MRI, LIS);
    } else
      extendDef(Idx, LocNo, 0, 0, 0, LIS, MDT);
  }

  // Finally, erase all the undefs.
  for (LocMap::iterator I = locInts.begin(); I.valid();)
    if (I.value() == ~0u)
      I.erase();
    else
      ++I;
}

void UserValue::extendDef(SlotIndex Idx, unsigned LocNo,
                          LiveRange *LR, const VNInfo *VNI,
                          SmallVectorImpl<SlotIndex> *Kills,
                          LiveIntervals &LIS, MachineDominatorTree &MDT,
                          UserValueScopes &UVS) {
  SmallVector<SlotIndex, 16> Todo;
  Todo.push_back(Idx);
  do {
    SlotIndex Start = Todo.pop_back_val();
    MachineBasicBlock *MBB = LIS.getMBBFromIndex(Start);
    SlotIndex Stop = LIS.getMBBEndIdx(MBB);
    LocMap::iterator I = locInts.find(Start);

    // Limit to VNI's live range.
    bool ToEnd = true;
    if (LR && VNI) {
      LiveInterval::Segment *Segment = LR->getSegmentContaining(Start);
      if (!Segment || Segment->valno != VNI) {
        if (Kills)
          Kills->push_back(Start);
        continue;
      }
      if (Segment->end < Stop)
        Stop = Segment->end, ToEnd = false;
    }

    // There could already be a short def at Start.
    if (I.valid() && I.start() <= Start) {
      // Stop when meeting a different location or an already extended interval.
      Start = Start.getNextSlot();
      if (I.value() != LocNo || I.stop() != Start)
        continue;
      // This is a one-slot placeholder. Just skip it.
      ++I;
    }

    // Limited by the next def.
    if (I.valid() && I.start() < Stop)
      Stop = I.start(), ToEnd = false;
    // Limited by VNI's live range.
    else if (!ToEnd && Kills)
      Kills->push_back(Stop);

    if (Start >= Stop)
      continue;

    I.insert(Start, Stop, LocNo);

    // If we extended to the MBB end, propagate down the dominator tree.
    if (!ToEnd)
      continue;
    const std::vector<MachineDomTreeNode*> &Children =
      MDT.getNode(MBB)->getChildren();
    for (unsigned i = 0, e = Children.size(); i != e; ++i) {
      MachineBasicBlock *MBB = Children[i]->getBlock();
      if (UVS.dominates(MBB))
        Todo.push_back(LIS.getMBBStartIdx(MBB));
    }
  } while (!Todo.empty());
}

/// We only propagate DBG_VALUES locally here. LiveDebugValues performs a
/// data-flow analysis to propagate them beyond basic block boundaries.
void UserValue::extendDef(SlotIndex Idx, unsigned LocNo, LiveRange *LR,
                          const VNInfo *VNI, SmallVectorImpl<SlotIndex> *Kills,
                          LiveIntervals &LIS, MachineDominatorTree &MDT,
                          UserValueScopes &UVS) {
  SlotIndex Start = Idx;
  MachineBasicBlock *MBB = LIS.getMBBFromIndex(Start);
  SlotIndex Stop = LIS.getMBBEndIdx(MBB);
  LocMap::iterator I = locInts.find(Start);

  // Limit to VNI's live range.
  bool ToEnd = true;
  if (LR && VNI) {
    LiveInterval::Segment *Segment = LR->getSegmentContaining(Start);
    if (!Segment || Segment->valno != VNI) {
      if (Kills)
        Kills->push_back(Start);
      return;
    }
    if (Segment->end < Stop) {
      Stop = Segment->end;
      ToEnd = false;
    }
  }

  // There could already be a short def at Start.
  if (I.valid() && I.start() <= Start) {
    // Stop when meeting a different location or an already extended interval.
    Start = Start.getNextSlot();
    if (I.value() != LocNo || I.stop() != Start)
      return;
    // This is a one-slot placeholder. Just skip it.
    ++I;
  }

  // Limited by the next def.
  if (I.valid() && I.start() < Stop) {
    Stop = I.start();
    ToEnd = false;
  }
  // Limited by VNI's live range.
  else if (!ToEnd && Kills)
    Kills->push_back(Stop);

  if (Start < Stop)
    I.insert(Start, Stop, LocNo);
}

void
UserValue::addDefsFromCopies(LiveInterval *LI, unsigned LocNo,
                      const SmallVectorImpl<SlotIndex> &Kills,
                      SmallVectorImpl<std::pair<SlotIndex, unsigned> > &NewDefs,
                      MachineRegisterInfo &MRI, LiveIntervals &LIS) {
  if (Kills.empty())
    return;
  // Don't track copies from physregs, there are too many uses.
  if (!TargetRegisterInfo::isVirtualRegister(LI->reg))
    return;

  // Collect all the (vreg, valno) pairs that are copies of LI.
  SmallVector<std::pair<LiveInterval*, const VNInfo*>, 8> CopyValues;
  for (MachineRegisterInfo::use_nodbg_iterator
         UI = MRI.use_nodbg_begin(LI->reg),
         UE = MRI.use_nodbg_end(); UI != UE; ++UI) {
    // Copies of the full value.
    if (UI.getOperand().getSubReg() || !UI->isCopy())
      continue;
    MachineInstr *MI = &*UI;
    unsigned DstReg = MI->getOperand(0).getReg();

    // Don't follow copies to physregs. These are usually setting up call
    // arguments, and the argument registers are always call clobbered. We are
    // better off in the source register which could be a callee-saved register,
    // or it could be spilled.
    if (!TargetRegisterInfo::isVirtualRegister(DstReg))
      continue;

    // Is LocNo extended to reach this copy? If not, another def may be blocking
    // it, or we are looking at a wrong value of LI.
    SlotIndex Idx = LIS.getInstructionIndex(MI);
    LocMap::iterator I = locInts.find(Idx.getRegSlot(true));
    if (!I.valid() || I.value() != LocNo)
      continue;

    if (!LIS.hasInterval(DstReg))
      continue;
    LiveInterval *DstLI = &LIS.getInterval(DstReg);
    const VNInfo *DstVNI = DstLI->getVNInfoAt(Idx.getRegSlot());
    assert(DstVNI && DstVNI->def == Idx.getRegSlot() && "Bad copy value");
    CopyValues.push_back(std::make_pair(DstLI, DstVNI));
  }

  if (CopyValues.empty())
    return;

  DEBUG(dbgs() << "Got " << CopyValues.size() << " copies of " << *LI << '\n');

  // Try to add defs of the copied values for each kill point.
  for (unsigned i = 0, e = Kills.size(); i != e; ++i) {
    SlotIndex Idx = Kills[i];
    for (unsigned j = 0, e = CopyValues.size(); j != e; ++j) {
      LiveInterval *DstLI = CopyValues[j].first;
      const VNInfo *DstVNI = CopyValues[j].second;
      if (DstLI->getVNInfoAt(Idx) != DstVNI)
        continue;
      // Check that there isn't already a def at Idx
      LocMap::iterator I = locInts.find(Idx);
      if (I.valid() && I.start() <= Idx)
        continue;
      DEBUG(dbgs() << "Kill at " << Idx << " covered by valno #"
                   << DstVNI->id << " in " << *DstLI << '\n');
      MachineInstr *CopyMI = LIS.getInstructionFromIndex(DstVNI->def);
      assert(CopyMI && CopyMI->isCopy() && "Bad copy value");
      unsigned LocNo = getLocationNo(CopyMI->getOperand(0));
      I.insert(Idx, Idx.getNextSlot(), LocNo);
      NewDefs.push_back(std::make_pair(Idx, LocNo));
      break;
    }
  }
}

void UserValue::computeIntervals(MachineRegisterInfo &MRI,
                                 const TargetRegisterInfo &TRI,
                                 LiveIntervals &LIS, LexicalScopes &LS) {
  SmallVector<std::pair<SlotIndex, unsigned>, 16> Defs;

  // Collect all defs to be extended (Skipping undefs).
  for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I)
    if (I.value() != UndefLocNo)
      Defs.push_back(std::make_pair(I.start(), I.value()));

  // Extend all defs, and possibly add new ones along the way.
  for (unsigned i = 0; i != Defs.size(); ++i) {
    SlotIndex Idx = Defs[i].first;
    unsigned LocNo = Defs[i].second;
    const MachineOperand &Loc = locations[LocNo];

    if (!Loc.isReg()) {
      extendDef(Idx, LocNo, nullptr, nullptr, nullptr, LIS);
      continue;
    }

    // Register locations are constrained to where the register value is live.
    if (TargetRegisterInfo::isVirtualRegister(Loc.getReg())) {
      LiveInterval *LI = nullptr;
      const VNInfo *VNI = nullptr;
      if (LIS.hasInterval(Loc.getReg())) {
        LI = &LIS.getInterval(Loc.getReg());
        VNI = LI->getVNInfoAt(Idx);
      }
      SmallVector<SlotIndex, 16> Kills;
      extendDef(Idx, LocNo, LI, VNI, &Kills, LIS);
      if (LI)
        addDefsFromCopies(LI, LocNo, Kills, Defs, MRI, LIS);
      continue;
    }

    // For physregs, use the live range of the first regunit as a guide.
    unsigned Unit = *MCRegUnitIterator(Loc.getReg(), &TRI);
    LiveRange *LR = &LIS.getRegUnit(Unit);
    const VNInfo *VNI = LR->getVNInfoAt(Idx);
    // Don't track copies from physregs, it is too expensive.
    extendDef(Idx, LocNo, LR, VNI, nullptr, LIS);
  }

  // Erase all the undefs.
  for (LocMap::iterator I = locInts.begin(); I.valid();)
    if (I.value() == UndefLocNo)
      I.erase();
    else
      ++I;

  // The computed intervals may extend beyond the range of the debug
  // location's lexical scope. In this case, splitting of an interval
  // can result in an interval outside of the scope being created,
  // causing extra unnecessary DBG_VALUEs to be emitted. To prevent
  // this, trim the intervals to the lexical scope.

  LexicalScope *Scope = LS.findLexicalScope(dl);
  if (!Scope)
    return;

  SlotIndex PrevEnd;
  LocMap::iterator I = locInts.begin();

  // Iterate over the lexical scope ranges. Each time round the loop
  // we check the intervals for overlap with the end of the previous
  // range and the start of the next. The first range is handled as
  // a special case where there is no PrevEnd.
  for (const InsnRange &Range : Scope->getRanges()) {
    SlotIndex RStart = LIS.getInstructionIndex(*Range.first);
    SlotIndex REnd = LIS.getInstructionIndex(*Range.second);

    // At the start of each iteration I has been advanced so that
    // I.stop() >= PrevEnd. Check for overlap.
    if (PrevEnd && I.start() < PrevEnd) {
      SlotIndex IStop = I.stop();
      unsigned LocNo = I.value();

      // Stop overlaps previous end - trim the end of the interval to
      // the scope range.
      I.setStopUnchecked(PrevEnd);
      ++I;

      // If the interval also overlaps the start of the "next" (i.e.
      // current) range create a new interval for the remainder (which
      // may be further trimmed).
      if (RStart < IStop)
        I.insert(RStart, IStop, LocNo);
    }

    // Advance I so that I.stop() >= RStart, and check for overlap.
    I.advanceTo(RStart);
    if (!I.valid())
      return;

    if (I.start() < RStart) {
      // Interval start overlaps range - trim to the scope range.
      I.setStartUnchecked(RStart);
      // Remember that this interval was trimmed.
      trimmedDefs.insert(RStart);
//.........这里部分代码省略.........