MachineModuleInfo.cpp

  for (unsigned I = 0; I != TyInfoSize; ++I)
    IdsInFilter[I] = getTypeIDFor(TyInfo[I]);

  LP.TypeIds.push_back(getFilterIDFor(IdsInFilter));
}

/// addCleanup - Add a cleanup action for a landing pad.
///
void MachineModuleInfo::addCleanup(MachineBasicBlock *LandingPad) {
  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
  LP.TypeIds.push_back(0);
}

/// TidyLandingPads - Remap landing pad labels and remove any deleted landing
/// pads.
void MachineModuleInfo::TidyLandingPads() {
  for (unsigned i = 0; i != LandingPads.size(); ) {
    LandingPadInfo &LandingPad = LandingPads[i];
    LandingPad.LandingPadLabel = MappedLabel(LandingPad.LandingPadLabel);

    // Special case: we *should* emit LPs with null LP MBB. This indicates
    // "nounwind" case.
    if (!LandingPad.LandingPadLabel && LandingPad.LandingPadBlock) {
      LandingPads.erase(LandingPads.begin() + i);
      continue;
    }

    for (unsigned j = 0; j != LandingPads[i].BeginLabels.size(); ) {
      unsigned BeginLabel = MappedLabel(LandingPad.BeginLabels[j]);
      unsigned EndLabel = MappedLabel(LandingPad.EndLabels[j]);

      if (!BeginLabel || !EndLabel) {
        LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
        LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
        continue;
      }

      LandingPad.BeginLabels[j] = BeginLabel;
      LandingPad.EndLabels[j] = EndLabel;
      ++j;
    }

    // Remove landing pads with no try-ranges.
    if (LandingPads[i].BeginLabels.empty()) {
      LandingPads.erase(LandingPads.begin() + i);
      continue;
    }

    // If there is no landing pad, ensure that the list of typeids is empty.
    // If the only typeid is a cleanup, this is the same as having no typeids.
    if (!LandingPad.LandingPadBlock ||
        (LandingPad.TypeIds.size() == 1 && !LandingPad.TypeIds[0]))
      LandingPad.TypeIds.clear();

    ++i;
  }
}

/// getTypeIDFor - Return the type id for the specified typeinfo.  This is 
/// function wide.
unsigned MachineModuleInfo::getTypeIDFor(GlobalVariable *TI) {
  for (unsigned i = 0, e = TypeInfos.size(); i != e; ++i)
    if (TypeInfos[i] == TI)
      return i + 1;

  TypeInfos.push_back(TI);
  return TypeInfos.size();
}

/// getFilterIDFor - Return the filter id for the specified typeinfos.  This is
/// function wide.
int MachineModuleInfo::getFilterIDFor(std::vector<unsigned> &TyIds) {
  // If the new filter coincides with the tail of an existing filter, then
  // re-use the existing filter.  Folding filters more than this requires
  // re-ordering filters and/or their elements - probably not worth it.
  for (std::vector<unsigned>::iterator I = FilterEnds.begin(),
       E = FilterEnds.end(); I != E; ++I) {
    unsigned i = *I, j = TyIds.size();

    while (i && j)
      if (FilterIds[--i] != TyIds[--j])
        goto try_next;

    if (!j)
      // The new filter coincides with range [i, end) of the existing filter.
      return -(1 + i);

try_next:;
  }

  // Add the new filter.
  int FilterID = -(1 + FilterIds.size());
  FilterIds.reserve(FilterIds.size() + TyIds.size() + 1);

  for (unsigned I = 0, N = TyIds.size(); I != N; ++I)
    FilterIds.push_back(TyIds[I]);

  FilterEnds.push_back(FilterIds.size());
  FilterIds.push_back(0); // terminator
  return FilterID;
}

/// getPersonality - Return the personality function for the current function.
Function *MachineModuleInfo::getPersonality() const {
  // FIXME: Until PR1414 will be fixed, we're using 1 personality function per
  // function
  return !LandingPads.empty() ? LandingPads[0].Personality : NULL;
}

/// getPersonalityIndex - Return unique index for current personality
/// function. NULL personality function should always get zero index.
unsigned MachineModuleInfo::getPersonalityIndex() const {
  const Function* Personality = NULL;
  
  // Scan landing pads. If there is at least one non-NULL personality - use it.
  for (unsigned i = 0, e = LandingPads.size(); i != e; ++i)
    if (LandingPads[i].Personality) {
      Personality = LandingPads[i].Personality;
      break;
    }
  
  for (unsigned i = 0, e = Personalities.size(); i < e; ++i)
    if (Personalities[i] == Personality)
      return i;

  // This should never happen
  assert(0 && "Personality function should be set!");
  return 0;
}

//===----------------------------------------------------------------------===//
/// DebugLabelFolding pass - This pass prunes out redundant labels.  This allows
/// a info consumer to determine if the range of two labels is empty, by seeing
/// if the labels map to the same reduced label.

namespace llvm {

struct DebugLabelFolder : public MachineFunctionPass {
  static char ID;
  DebugLabelFolder() : MachineFunctionPass((intptr_t)&ID) {}

  virtual bool runOnMachineFunction(MachineFunction &MF);
  virtual const char *getPassName() const { return "Label Folder"; }
};

char DebugLabelFolder::ID = 0;

bool DebugLabelFolder::runOnMachineFunction(MachineFunction &MF) {
  // Get machine module info.
  MachineModuleInfo *MMI = getAnalysisToUpdate<MachineModuleInfo>();
  if (!MMI) return false;
  
  // Track if change is made.
  bool MadeChange = false;
  // No prior label to begin.
  unsigned PriorLabel = 0;
  
  // Iterate through basic blocks.
  for (MachineFunction::iterator BB = MF.begin(), E = MF.end();
       BB != E; ++BB) {
    // Iterate through instructions.
    for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) {
      // Is it a label.
      if (I->isDebugLabel()) {
        // The label ID # is always operand #0, an immediate.
        unsigned NextLabel = I->getOperand(0).getImm();
        
        // If there was an immediate prior label.
        if (PriorLabel) {
          // Remap the current label to prior label.
          MMI->RemapLabel(NextLabel, PriorLabel);
          // Delete the current label.
          I = BB->erase(I);
          // Indicate a change has been made.
          MadeChange = true;
          continue;
        } else {
          // Start a new round.
          PriorLabel = NextLabel;
        }
       } else {
        // No consecutive labels.
        PriorLabel = 0;
      }
      
      ++I;
    }
  }
  
  return MadeChange;
}

FunctionPass *createDebugLabelFoldingPass() { return new DebugLabelFolder(); }

}