C++ SmallPtrSetImpl::clear方法代码示例

/// Merge an autorelease with a retain into a fused call.
bool ObjCARCContract::contractAutorelease(
    Function &F, Instruction *Autorelease, ARCInstKind Class,
    SmallPtrSetImpl<Instruction *> &DependingInstructions,
    SmallPtrSetImpl<const BasicBlock *> &Visited) {
  const Value *Arg = GetArgRCIdentityRoot(Autorelease);

  // Check that there are no instructions between the retain and the autorelease
  // (such as an autorelease_pop) which may change the count.
  CallInst *Retain = nullptr;
  if (Class == ARCInstKind::AutoreleaseRV)
    FindDependencies(RetainAutoreleaseRVDep, Arg,
                     Autorelease->getParent(), Autorelease,
                     DependingInstructions, Visited, PA);
  else
    FindDependencies(RetainAutoreleaseDep, Arg,
                     Autorelease->getParent(), Autorelease,
                     DependingInstructions, Visited, PA);

  Visited.clear();
  if (DependingInstructions.size() != 1) {
    DependingInstructions.clear();
    return false;
  }

  Retain = dyn_cast_or_null<CallInst>(*DependingInstructions.begin());
  DependingInstructions.clear();

  if (!Retain || GetBasicARCInstKind(Retain) != ARCInstKind::Retain ||
      GetArgRCIdentityRoot(Retain) != Arg)
    return false;

  Changed = true;
  ++NumPeeps;

  LLVM_DEBUG(dbgs() << "    Fusing retain/autorelease!\n"
                       "        Autorelease:"
                    << *Autorelease
                    << "\n"
                       "        Retain: "
                    << *Retain << "\n");

  Function *Decl = EP.get(Class == ARCInstKind::AutoreleaseRV
                              ? ARCRuntimeEntryPointKind::RetainAutoreleaseRV
                              : ARCRuntimeEntryPointKind::RetainAutorelease);
  Retain->setCalledFunction(Decl);

  LLVM_DEBUG(dbgs() << "        New RetainAutorelease: " << *Retain << "\n");

  EraseInstruction(Autorelease);
  return true;
}

/// getMachineBasicBlocks - Populate given set using machine basic blocks which
/// have machine instructions that belong to lexical scope identified by
/// DebugLoc.
void LexicalScopes::getMachineBasicBlocks(
    const DILocation *DL, SmallPtrSetImpl<const MachineBasicBlock *> &MBBs) {
  MBBs.clear();
  LexicalScope *Scope = getOrCreateLexicalScope(DL);
  if (!Scope)
    return;

  if (Scope == CurrentFnLexicalScope) {
    for (const auto &MBB : *MF)
      MBBs.insert(&MBB);
    return;
  }

  SmallVectorImpl<InsnRange> &InsnRanges = Scope->getRanges();
  for (auto &R : InsnRanges)
    MBBs.insert(R.first->getParent());
}

/// getMachineBasicBlocks - Populate given set using machine basic blocks which
/// have machine instructions that belong to lexical scope identified by
/// DebugLoc.
void LexicalScopes::getMachineBasicBlocks(
    const MDLocation *DL, SmallPtrSetImpl<const MachineBasicBlock *> &MBBs) {
  MBBs.clear();
  LexicalScope *Scope = getOrCreateLexicalScope(DL);
  if (!Scope)
    return;

  if (Scope == CurrentFnLexicalScope) {
    for (const auto &MBB : *MF)
      MBBs.insert(&MBB);
    return;
  }

  SmallVectorImpl<InsnRange> &InsnRanges = Scope->getRanges();
  for (SmallVectorImpl<InsnRange>::iterator I = InsnRanges.begin(),
                                            E = InsnRanges.end();
       I != E; ++I) {
    InsnRange &R = *I;
    MBBs.insert(R.first->getParent());
  }
}