C++ SmallPtrSetImpl::insert方法代码示例

Optional<T> SubstitutionMap::forEachParent(
              CanType type,
              llvm::SmallPtrSetImpl<CanType> &visitedParents,
              llvm::function_ref<Optional<T>(CanType,
                                             AssociatedTypeDecl *)> fn) const {
  // If we've already visited the parents of this type, stop.
  if (!visitedParents.insert(type).second)
    return None;

  auto foundParents = parentMap.find(type.getPointer());
  if (foundParents != parentMap.end()) {
    for (auto parent : foundParents->second) {
      if (auto result = fn(parent.first, parent.second))
        return result;
    }
  }

  if (auto archetypeType = dyn_cast<ArchetypeType>(type))
    if (auto *parent = archetypeType->getParent())
      return fn(CanType(parent), archetypeType->getAssocType());

  if (auto memberType = dyn_cast<DependentMemberType>(type))
    return fn(CanType(memberType->getBase()), memberType->getAssocType());

  return None;
}

static void getModuleFileAncestors(
    ModuleFile *F,
    llvm::SmallPtrSetImpl<ModuleFile *> &Ancestors) {
  Ancestors.insert(F);
  for (ModuleFile *Importer : F->ImportedBy)
    getModuleFileAncestors(Importer, Ancestors);
}

void findExtensionsFromConformingProtocols(Decl *D,
                                           llvm::SmallPtrSetImpl<ExtensionDecl*> &Results) {
  NominalTypeDecl* NTD = dyn_cast<NominalTypeDecl>(D);
  if (!NTD || NTD->getKind() == DeclKind::Protocol)
    return;
  std::vector<NominalTypeDecl*> Unhandled;
  auto addTypeLocNominal = [&](TypeLoc TL){
    if (TL.getType()) {
      if (auto D = TL.getType()->getAnyNominal()) {
        Unhandled.push_back(D);
      }
    }
  };
  for (auto TL : NTD->getInherited()) {
    addTypeLocNominal(TL);
  }
  while(!Unhandled.empty()) {
    NominalTypeDecl* Back = Unhandled.back();
    Unhandled.pop_back();
    for (ExtensionDecl *E : Back->getExtensions()) {
      if(E->isConstrainedExtension())
        Results.insert(E);
      for (auto TL : Back->getInherited()) {
        addTypeLocNominal(TL);
      }
    }
  }
}

// Propagate liveness backwards from an initial set of blocks in our
// LiveIn set.
static void propagateLiveness(llvm::SmallPtrSetImpl<SILBasicBlock *> &LiveIn,
                              SILBasicBlock *DefBB) {
  // First populate a worklist of predecessors.
  llvm::SmallVector<SILBasicBlock *, 64> Worklist;
  for (auto *BB : LiveIn)
    for (auto Pred : BB->getPreds())
      Worklist.push_back(Pred);

  // Now propagate liveness backwards until we hit the alloc_box.
  while (!Worklist.empty()) {
    auto *BB = Worklist.pop_back_val();

    // If it's already in the set, then we've already queued and/or
    // processed the predecessors.
    if (BB == DefBB || !LiveIn.insert(BB).second)
      continue;

    for (auto Pred : BB->getPreds())
      Worklist.push_back(Pred);
  }
}

/// \brief Issue an "unreachable code" diagnostic if the blocks contains or
/// leads to another block that contains user code.
///
/// Note, we rely on SILLocation information to determine if SILInstructions
/// correspond to user code.
static bool diagnoseUnreachableBlock(const SILBasicBlock &B,
                                     SILModule &M,
                                     const SILBasicBlockSet &Reachable,
                                     UnreachableUserCodeReportingState *State,
                                     const SILBasicBlock *TopLevelB,
                         llvm::SmallPtrSetImpl<const SILBasicBlock*> &Visited){
  if (Visited.count(&B))
    return false;
  Visited.insert(&B);
  
  assert(State);
  for (auto I = B.begin(), E = B.end(); I != E; ++I) {
    SILLocation Loc = I->getLoc();
    // If we've reached an implicit return, we have not found any user code and
    // can stop searching for it.
    if (Loc.is<ImplicitReturnLocation>() || Loc.isAutoGenerated())
      return false;

    // Check if the instruction corresponds to user-written code, also make
    // sure we don't report an error twice for the same instruction.
    if (isUserCode(&*I) && !State->BlocksWithErrors.count(&B)) {

      // Emit the diagnostic.
      auto BrInfoIter = State->MetaMap.find(TopLevelB);
      assert(BrInfoIter != State->MetaMap.end());
      auto BrInfo = BrInfoIter->second;

      switch (BrInfo.Kind) {
      case (UnreachableKind::FoldedBranch):
        // Emit the diagnostic on the unreachable block and emit the
        // note on the branch responsible for the unreachable code.
        diagnose(M.getASTContext(), Loc.getSourceLoc(), diag::unreachable_code);
        diagnose(M.getASTContext(), BrInfo.Loc.getSourceLoc(),
                 diag::unreachable_code_branch, BrInfo.CondIsAlwaysTrue);
        break;

      case (UnreachableKind::FoldedSwitchEnum): {
        // If we are warning about a switch condition being a constant, the main
        // emphasis should be on the condition (to ensure we have a single
        // message per switch).
        const SwitchStmt *SS = BrInfo.Loc.getAsASTNode<SwitchStmt>();
        if (!SS)
          break;
        assert(SS);
        const Expr *SE = SS->getSubjectExpr();
        diagnose(M.getASTContext(), SE->getLoc(), diag::switch_on_a_constant);
        diagnose(M.getASTContext(), Loc.getSourceLoc(),
                 diag::unreachable_code_note);
        break;
      }

      case (UnreachableKind::NoreturnCall): {
        // Specialcase when we are warning about unreachable code after a call
        // to a noreturn function.
        if (!BrInfo.Loc.isASTNode<ExplicitCastExpr>()) {
          assert(BrInfo.Loc.isASTNode<ApplyExpr>());
          diagnose(M.getASTContext(), Loc.getSourceLoc(),
                   diag::unreachable_code);
          diagnose(M.getASTContext(), BrInfo.Loc.getSourceLoc(),
                   diag::call_to_noreturn_note);
        }
        break;
      }
      }

      // Record that we've reported this unreachable block to avoid duplicates
      // in the future.
      State->BlocksWithErrors.insert(&B);
      return true;
    }
  }

  // This block could be empty if it's terminator has been folded.
  if (B.empty())
    return false;

  // If we have not found user code in this block, inspect it's successors.
  // Check if at least one of the successors contains user code.
  for (auto I = B.succ_begin(), E = B.succ_end(); I != E; ++I) {
    SILBasicBlock *SB = *I;
    bool HasReachablePred = false;
    for (auto PI = SB->pred_begin(), PE = SB->pred_end(); PI != PE; ++PI) {
      if (Reachable.count(*PI))
        HasReachablePred = true;
    }

    // If all of the predecessors of this successor are unreachable, check if
    // it contains user code.
    if (!HasReachablePred && diagnoseUnreachableBlock(*SB, M, Reachable,
                                                    State, TopLevelB, Visited))
      return true;
  }
  
  return false;
}