Ejemplo n.º 1
0
ObjCAtCatchStmt::ObjCAtCatchStmt(SourceLocation atCatchLoc,
                                 SourceLocation rparenloc,
                                 ParmVarDecl *catchVarDecl, Stmt *atCatchStmt,
                                 Stmt *atCatchList)
: Stmt(ObjCAtCatchStmtClass) {
  ExceptionDecl = catchVarDecl;
  SubExprs[BODY] = atCatchStmt;
  SubExprs[NEXT_CATCH] = NULL;
  // FIXME: O(N^2) in number of catch blocks.
  if (atCatchList) {
    ObjCAtCatchStmt *AtCatchList = static_cast<ObjCAtCatchStmt*>(atCatchList);

    while (ObjCAtCatchStmt* NextCatch = AtCatchList->getNextCatchStmt())
      AtCatchList = NextCatch;

    AtCatchList->SubExprs[NEXT_CATCH] = this;
  }
  AtCatchLoc = atCatchLoc;
  RParenLoc = rparenloc;
}
Ejemplo n.º 2
0
/// BuildScopeInformation - The statements from CI to CE are known to form a
/// coherent VLA scope with a specified parent node.  Walk through the
/// statements, adding any labels or gotos to LabelAndGotoScopes and recursively
/// walking the AST as needed.
void JumpScopeChecker::BuildScopeInformation(Stmt *S, unsigned &origParentScope) {
  // If this is a statement, rather than an expression, scopes within it don't
  // propagate out into the enclosing scope.  Otherwise we have to worry
  // about block literals, which have the lifetime of their enclosing statement.
  unsigned independentParentScope = origParentScope;
  unsigned &ParentScope = ((isa<Expr>(S) && !isa<StmtExpr>(S)) 
                            ? origParentScope : independentParentScope);

  bool SkipFirstSubStmt = false;
  
  // If we found a label, remember that it is in ParentScope scope.
  switch (S->getStmtClass()) {
  case Stmt::AddrLabelExprClass:
    IndirectJumpTargets.push_back(cast<AddrLabelExpr>(S)->getLabel());
    break;

  case Stmt::IndirectGotoStmtClass:
    // "goto *&&lbl;" is a special case which we treat as equivalent
    // to a normal goto.  In addition, we don't calculate scope in the
    // operand (to avoid recording the address-of-label use), which
    // works only because of the restricted set of expressions which
    // we detect as constant targets.
    if (cast<IndirectGotoStmt>(S)->getConstantTarget()) {
      LabelAndGotoScopes[S] = ParentScope;
      Jumps.push_back(S);
      return;
    }

    LabelAndGotoScopes[S] = ParentScope;
    IndirectJumps.push_back(cast<IndirectGotoStmt>(S));
    break;

  case Stmt::SwitchStmtClass:
    // Evaluate the condition variable before entering the scope of the switch
    // statement.
    if (VarDecl *Var = cast<SwitchStmt>(S)->getConditionVariable()) {
      BuildScopeInformation(Var, ParentScope);
      SkipFirstSubStmt = true;
    }
    // Fall through
      
  case Stmt::GotoStmtClass:
    // Remember both what scope a goto is in as well as the fact that we have
    // it.  This makes the second scan not have to walk the AST again.
    LabelAndGotoScopes[S] = ParentScope;
    Jumps.push_back(S);
    break;

  case Stmt::CXXTryStmtClass: {
    CXXTryStmt *TS = cast<CXXTryStmt>(S);
    unsigned newParentScope;
    Scopes.push_back(GotoScope(ParentScope,
                               diag::note_protected_by_cxx_try,
                               diag::note_exits_cxx_try,
                               TS->getSourceRange().getBegin()));
    if (Stmt *TryBlock = TS->getTryBlock())
      BuildScopeInformation(TryBlock, (newParentScope = Scopes.size()-1));

    // Jump from the catch into the try is not allowed either.
    for (unsigned I = 0, E = TS->getNumHandlers(); I != E; ++I) {
      CXXCatchStmt *CS = TS->getHandler(I);
      Scopes.push_back(GotoScope(ParentScope,
                                 diag::note_protected_by_cxx_catch,
                                 diag::note_exits_cxx_catch,
                                 CS->getSourceRange().getBegin()));
      BuildScopeInformation(CS->getHandlerBlock(), 
                            (newParentScope = Scopes.size()-1));
    }
    return;
  }

  default:
    break;
  }

  for (Stmt::child_range CI = S->children(); CI; ++CI) {
    if (SkipFirstSubStmt) {
      SkipFirstSubStmt = false;
      continue;
    }
    
    Stmt *SubStmt = *CI;
    if (SubStmt == 0) continue;

    // Cases, labels, and defaults aren't "scope parents".  It's also
    // important to handle these iteratively instead of recursively in
    // order to avoid blowing out the stack.
    while (true) {
      Stmt *Next;
      if (CaseStmt *CS = dyn_cast<CaseStmt>(SubStmt))
        Next = CS->getSubStmt();
      else if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SubStmt))
        Next = DS->getSubStmt();
      else if (LabelStmt *LS = dyn_cast<LabelStmt>(SubStmt))
        Next = LS->getSubStmt();
      else
        break;

      LabelAndGotoScopes[SubStmt] = ParentScope;
      SubStmt = Next;
    }

    // If this is a declstmt with a VLA definition, it defines a scope from here
    // to the end of the containing context.
    if (DeclStmt *DS = dyn_cast<DeclStmt>(SubStmt)) {
      // The decl statement creates a scope if any of the decls in it are VLAs
      // or have the cleanup attribute.
      for (DeclStmt::decl_iterator I = DS->decl_begin(), E = DS->decl_end();
           I != E; ++I)
        BuildScopeInformation(*I, ParentScope);
      continue;
    }
    // Disallow jumps into any part of an @try statement by pushing a scope and
    // walking all sub-stmts in that scope.
    if (ObjCAtTryStmt *AT = dyn_cast<ObjCAtTryStmt>(SubStmt)) {
      unsigned newParentScope;
      // Recursively walk the AST for the @try part.
      Scopes.push_back(GotoScope(ParentScope,
                                 diag::note_protected_by_objc_try,
                                 diag::note_exits_objc_try,
                                 AT->getAtTryLoc()));
      if (Stmt *TryPart = AT->getTryBody())
        BuildScopeInformation(TryPart, (newParentScope = Scopes.size()-1));

      // Jump from the catch to the finally or try is not valid.
      for (unsigned I = 0, N = AT->getNumCatchStmts(); I != N; ++I) {
        ObjCAtCatchStmt *AC = AT->getCatchStmt(I);
        Scopes.push_back(GotoScope(ParentScope,
                                   diag::note_protected_by_objc_catch,
                                   diag::note_exits_objc_catch,
                                   AC->getAtCatchLoc()));
        // @catches are nested and it isn't
        BuildScopeInformation(AC->getCatchBody(), 
                              (newParentScope = Scopes.size()-1));
      }

      // Jump from the finally to the try or catch is not valid.
      if (ObjCAtFinallyStmt *AF = AT->getFinallyStmt()) {
        Scopes.push_back(GotoScope(ParentScope,
                                   diag::note_protected_by_objc_finally,
                                   diag::note_exits_objc_finally,
                                   AF->getAtFinallyLoc()));
        BuildScopeInformation(AF, (newParentScope = Scopes.size()-1));
      }

      continue;
    }
    
    unsigned newParentScope;
    // Disallow jumps into the protected statement of an @synchronized, but
    // allow jumps into the object expression it protects.
    if (ObjCAtSynchronizedStmt *AS = dyn_cast<ObjCAtSynchronizedStmt>(SubStmt)){
      // Recursively walk the AST for the @synchronized object expr, it is
      // evaluated in the normal scope.
      BuildScopeInformation(AS->getSynchExpr(), ParentScope);

      // Recursively walk the AST for the @synchronized part, protected by a new
      // scope.
      Scopes.push_back(GotoScope(ParentScope,
                                 diag::note_protected_by_objc_synchronized,
                                 diag::note_exits_objc_synchronized,
                                 AS->getAtSynchronizedLoc()));
      BuildScopeInformation(AS->getSynchBody(), 
                            (newParentScope = Scopes.size()-1));
      continue;
    }

    // Disallow jumps into the protected statement of an @autoreleasepool.
    if (ObjCAutoreleasePoolStmt *AS = dyn_cast<ObjCAutoreleasePoolStmt>(SubStmt)){
      // Recursively walk the AST for the @autoreleasepool part, protected by a new
      // scope.
      Scopes.push_back(GotoScope(ParentScope,
                                 diag::note_protected_by_objc_autoreleasepool,
                                 diag::note_exits_objc_autoreleasepool,
                                 AS->getAtLoc()));
      BuildScopeInformation(AS->getSubStmt(), (newParentScope = Scopes.size()-1));
      continue;
    }

    // Disallow jumps past full-expressions that use blocks with
    // non-trivial cleanups of their captures.  This is theoretically
    // implementable but a lot of work which we haven't felt up to doing.
    if (ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(SubStmt)) {
      for (unsigned i = 0, e = EWC->getNumObjects(); i != e; ++i) {
        const BlockDecl *BDecl = EWC->getObject(i);
        for (BlockDecl::capture_const_iterator ci = BDecl->capture_begin(),
             ce = BDecl->capture_end(); ci != ce; ++ci) {
          VarDecl *variable = ci->getVariable();
          BuildScopeInformation(variable, BDecl, ParentScope);
        }
      }
    }
    
    // Recursively walk the AST.
    BuildScopeInformation(SubStmt, ParentScope);
  }
}
Ejemplo n.º 3
0
/// BuildScopeInformation - The statements from CI to CE are known to form a
/// coherent VLA scope with a specified parent node.  Walk through the
/// statements, adding any labels or gotos to LabelAndGotoScopes and recursively
/// walking the AST as needed.
void JumpScopeChecker::BuildScopeInformation(Stmt *S,
                                             unsigned &origParentScope) {
  // If this is a statement, rather than an expression, scopes within it don't
  // propagate out into the enclosing scope.  Otherwise we have to worry
  // about block literals, which have the lifetime of their enclosing statement.
  unsigned independentParentScope = origParentScope;
  unsigned &ParentScope = ((isa<Expr>(S) && !isa<StmtExpr>(S))
                            ? origParentScope : independentParentScope);

  unsigned StmtsToSkip = 0u;

  // If we found a label, remember that it is in ParentScope scope.
  switch (S->getStmtClass()) {
  case Stmt::AddrLabelExprClass:
    IndirectJumpTargets.push_back(cast<AddrLabelExpr>(S)->getLabel());
    break;

  case Stmt::ObjCForCollectionStmtClass: {
    auto *CS = cast<ObjCForCollectionStmt>(S);
    unsigned Diag = diag::note_protected_by_objc_fast_enumeration;
    unsigned NewParentScope = Scopes.size();
    Scopes.push_back(GotoScope(ParentScope, Diag, 0, S->getLocStart()));
    BuildScopeInformation(CS->getBody(), NewParentScope);
    return;
  }

  case Stmt::IndirectGotoStmtClass:
    // "goto *&&lbl;" is a special case which we treat as equivalent
    // to a normal goto.  In addition, we don't calculate scope in the
    // operand (to avoid recording the address-of-label use), which
    // works only because of the restricted set of expressions which
    // we detect as constant targets.
    if (cast<IndirectGotoStmt>(S)->getConstantTarget()) {
      LabelAndGotoScopes[S] = ParentScope;
      Jumps.push_back(S);
      return;
    }

    LabelAndGotoScopes[S] = ParentScope;
    IndirectJumps.push_back(cast<IndirectGotoStmt>(S));
    break;

  case Stmt::SwitchStmtClass:
    // Evaluate the C++17 init stmt and condition variable
    // before entering the scope of the switch statement.
    if (Stmt *Init = cast<SwitchStmt>(S)->getInit()) {
      BuildScopeInformation(Init, ParentScope);
      ++StmtsToSkip;
    }
    if (VarDecl *Var = cast<SwitchStmt>(S)->getConditionVariable()) {
      BuildScopeInformation(Var, ParentScope);
      ++StmtsToSkip;
    }
    LLVM_FALLTHROUGH;

  case Stmt::GotoStmtClass:
    // Remember both what scope a goto is in as well as the fact that we have
    // it.  This makes the second scan not have to walk the AST again.
    LabelAndGotoScopes[S] = ParentScope;
    Jumps.push_back(S);
    break;

  case Stmt::IfStmtClass: {
    IfStmt *IS = cast<IfStmt>(S);
    if (!(IS->isConstexpr() || IS->isObjCAvailabilityCheck()))
      break;

    unsigned Diag = IS->isConstexpr() ? diag::note_protected_by_constexpr_if
                                      : diag::note_protected_by_if_available;

    if (VarDecl *Var = IS->getConditionVariable())
      BuildScopeInformation(Var, ParentScope);

    // Cannot jump into the middle of the condition.
    unsigned NewParentScope = Scopes.size();
    Scopes.push_back(GotoScope(ParentScope, Diag, 0, IS->getLocStart()));
    BuildScopeInformation(IS->getCond(), NewParentScope);

    // Jumps into either arm of an 'if constexpr' are not allowed.
    NewParentScope = Scopes.size();
    Scopes.push_back(GotoScope(ParentScope, Diag, 0, IS->getLocStart()));
    BuildScopeInformation(IS->getThen(), NewParentScope);
    if (Stmt *Else = IS->getElse()) {
      NewParentScope = Scopes.size();
      Scopes.push_back(GotoScope(ParentScope, Diag, 0, IS->getLocStart()));
      BuildScopeInformation(Else, NewParentScope);
    }
    return;
  }

  case Stmt::CXXTryStmtClass: {
    CXXTryStmt *TS = cast<CXXTryStmt>(S);
    {
      unsigned NewParentScope = Scopes.size();
      Scopes.push_back(GotoScope(ParentScope,
                                 diag::note_protected_by_cxx_try,
                                 diag::note_exits_cxx_try,
                                 TS->getSourceRange().getBegin()));
      if (Stmt *TryBlock = TS->getTryBlock())
        BuildScopeInformation(TryBlock, NewParentScope);
    }

    // Jump from the catch into the try is not allowed either.
    for (unsigned I = 0, E = TS->getNumHandlers(); I != E; ++I) {
      CXXCatchStmt *CS = TS->getHandler(I);
      unsigned NewParentScope = Scopes.size();
      Scopes.push_back(GotoScope(ParentScope,
                                 diag::note_protected_by_cxx_catch,
                                 diag::note_exits_cxx_catch,
                                 CS->getSourceRange().getBegin()));
      BuildScopeInformation(CS->getHandlerBlock(), NewParentScope);
    }
    return;
  }

  case Stmt::SEHTryStmtClass: {
    SEHTryStmt *TS = cast<SEHTryStmt>(S);
    {
      unsigned NewParentScope = Scopes.size();
      Scopes.push_back(GotoScope(ParentScope,
                                 diag::note_protected_by_seh_try,
                                 diag::note_exits_seh_try,
                                 TS->getSourceRange().getBegin()));
      if (Stmt *TryBlock = TS->getTryBlock())
        BuildScopeInformation(TryBlock, NewParentScope);
    }

    // Jump from __except or __finally into the __try are not allowed either.
    if (SEHExceptStmt *Except = TS->getExceptHandler()) {
      unsigned NewParentScope = Scopes.size();
      Scopes.push_back(GotoScope(ParentScope,
                                 diag::note_protected_by_seh_except,
                                 diag::note_exits_seh_except,
                                 Except->getSourceRange().getBegin()));
      BuildScopeInformation(Except->getBlock(), NewParentScope);
    } else if (SEHFinallyStmt *Finally = TS->getFinallyHandler()) {
      unsigned NewParentScope = Scopes.size();
      Scopes.push_back(GotoScope(ParentScope,
                                 diag::note_protected_by_seh_finally,
                                 diag::note_exits_seh_finally,
                                 Finally->getSourceRange().getBegin()));
      BuildScopeInformation(Finally->getBlock(), NewParentScope);
    }

    return;
  }

  case Stmt::DeclStmtClass: {
    // If this is a declstmt with a VLA definition, it defines a scope from here
    // to the end of the containing context.
    DeclStmt *DS = cast<DeclStmt>(S);
    // The decl statement creates a scope if any of the decls in it are VLAs
    // or have the cleanup attribute.
    for (auto *I : DS->decls())
      BuildScopeInformation(I, origParentScope);
    return;
  }

  case Stmt::ObjCAtTryStmtClass: {
    // Disallow jumps into any part of an @try statement by pushing a scope and
    // walking all sub-stmts in that scope.
    ObjCAtTryStmt *AT = cast<ObjCAtTryStmt>(S);
    // Recursively walk the AST for the @try part.
    {
      unsigned NewParentScope = Scopes.size();
      Scopes.push_back(GotoScope(ParentScope,
                                 diag::note_protected_by_objc_try,
                                 diag::note_exits_objc_try,
                                 AT->getAtTryLoc()));
      if (Stmt *TryPart = AT->getTryBody())
        BuildScopeInformation(TryPart, NewParentScope);
    }

    // Jump from the catch to the finally or try is not valid.
    for (unsigned I = 0, N = AT->getNumCatchStmts(); I != N; ++I) {
      ObjCAtCatchStmt *AC = AT->getCatchStmt(I);
      unsigned NewParentScope = Scopes.size();
      Scopes.push_back(GotoScope(ParentScope,
                                 diag::note_protected_by_objc_catch,
                                 diag::note_exits_objc_catch,
                                 AC->getAtCatchLoc()));
      // @catches are nested and it isn't
      BuildScopeInformation(AC->getCatchBody(), NewParentScope);
    }

    // Jump from the finally to the try or catch is not valid.
    if (ObjCAtFinallyStmt *AF = AT->getFinallyStmt()) {
      unsigned NewParentScope = Scopes.size();
      Scopes.push_back(GotoScope(ParentScope,
                                 diag::note_protected_by_objc_finally,
                                 diag::note_exits_objc_finally,
                                 AF->getAtFinallyLoc()));
      BuildScopeInformation(AF, NewParentScope);
    }

    return;
  }

  case Stmt::ObjCAtSynchronizedStmtClass: {
    // Disallow jumps into the protected statement of an @synchronized, but
    // allow jumps into the object expression it protects.
    ObjCAtSynchronizedStmt *AS = cast<ObjCAtSynchronizedStmt>(S);
    // Recursively walk the AST for the @synchronized object expr, it is
    // evaluated in the normal scope.
    BuildScopeInformation(AS->getSynchExpr(), ParentScope);

    // Recursively walk the AST for the @synchronized part, protected by a new
    // scope.
    unsigned NewParentScope = Scopes.size();
    Scopes.push_back(GotoScope(ParentScope,
                               diag::note_protected_by_objc_synchronized,
                               diag::note_exits_objc_synchronized,
                               AS->getAtSynchronizedLoc()));
    BuildScopeInformation(AS->getSynchBody(), NewParentScope);
    return;
  }

  case Stmt::ObjCAutoreleasePoolStmtClass: {
    // Disallow jumps into the protected statement of an @autoreleasepool.
    ObjCAutoreleasePoolStmt *AS = cast<ObjCAutoreleasePoolStmt>(S);
    // Recursively walk the AST for the @autoreleasepool part, protected by a
    // new scope.
    unsigned NewParentScope = Scopes.size();
    Scopes.push_back(GotoScope(ParentScope,
                               diag::note_protected_by_objc_autoreleasepool,
                               diag::note_exits_objc_autoreleasepool,
                               AS->getAtLoc()));
    BuildScopeInformation(AS->getSubStmt(), NewParentScope);
    return;
  }

  case Stmt::ExprWithCleanupsClass: {
    // Disallow jumps past full-expressions that use blocks with
    // non-trivial cleanups of their captures.  This is theoretically
    // implementable but a lot of work which we haven't felt up to doing.
    ExprWithCleanups *EWC = cast<ExprWithCleanups>(S);
    for (unsigned i = 0, e = EWC->getNumObjects(); i != e; ++i) {
      const BlockDecl *BDecl = EWC->getObject(i);
      for (const auto &CI : BDecl->captures()) {
        VarDecl *variable = CI.getVariable();
        BuildScopeInformation(variable, BDecl, origParentScope);
      }
    }
    break;
  }

  case Stmt::MaterializeTemporaryExprClass: {
    // Disallow jumps out of scopes containing temporaries lifetime-extended to
    // automatic storage duration.
    MaterializeTemporaryExpr *MTE = cast<MaterializeTemporaryExpr>(S);
    if (MTE->getStorageDuration() == SD_Automatic) {
      SmallVector<const Expr *, 4> CommaLHS;
      SmallVector<SubobjectAdjustment, 4> Adjustments;
      const Expr *ExtendedObject =
          MTE->GetTemporaryExpr()->skipRValueSubobjectAdjustments(
              CommaLHS, Adjustments);
      if (ExtendedObject->getType().isDestructedType()) {
        Scopes.push_back(GotoScope(ParentScope, 0,
                                   diag::note_exits_temporary_dtor,
                                   ExtendedObject->getExprLoc()));
        origParentScope = Scopes.size()-1;
      }
    }
    break;
  }

  case Stmt::CaseStmtClass:
  case Stmt::DefaultStmtClass:
  case Stmt::LabelStmtClass:
    LabelAndGotoScopes[S] = ParentScope;
    break;

  default:
    break;
  }

  for (Stmt *SubStmt : S->children()) {
    if (!SubStmt)
        continue;
    if (StmtsToSkip) {
      --StmtsToSkip;
      continue;
    }

    // Cases, labels, and defaults aren't "scope parents".  It's also
    // important to handle these iteratively instead of recursively in
    // order to avoid blowing out the stack.
    while (true) {
      Stmt *Next;
      if (SwitchCase *SC = dyn_cast<SwitchCase>(SubStmt))
        Next = SC->getSubStmt();
      else if (LabelStmt *LS = dyn_cast<LabelStmt>(SubStmt))
        Next = LS->getSubStmt();
      else
        break;

      LabelAndGotoScopes[SubStmt] = ParentScope;
      SubStmt = Next;
    }

    // Recursively walk the AST.
    BuildScopeInformation(SubStmt, ParentScope);
  }
}
/// BuildScopeInformation - The statements from CI to CE are known to form a
/// coherent VLA scope with a specified parent node.  Walk through the
/// statements, adding any labels or gotos to LabelAndGotoScopes and recursively
/// walking the AST as needed.
void JumpScopeChecker::BuildScopeInformation(Stmt *S, unsigned ParentScope) {

  // If we found a label, remember that it is in ParentScope scope.
  if (isa<LabelStmt>(S) || isa<DefaultStmt>(S) || isa<CaseStmt>(S)) {
    LabelAndGotoScopes[S] = ParentScope;
  } else if (isa<GotoStmt>(S) || isa<SwitchStmt>(S) ||
             isa<IndirectGotoStmt>(S) || isa<AddrLabelExpr>(S)) {
    // Remember both what scope a goto is in as well as the fact that we have
    // it.  This makes the second scan not have to walk the AST again.
    LabelAndGotoScopes[S] = ParentScope;
    Jumps.push_back(S);
  }

  for (Stmt::child_iterator CI = S->child_begin(), E = S->child_end(); CI != E;
       ++CI) {
    Stmt *SubStmt = *CI;
    if (SubStmt == 0) continue;

    bool isCPlusPlus = this->S.getLangOptions().CPlusPlus;

    // If this is a declstmt with a VLA definition, it defines a scope from here
    // to the end of the containing context.
    if (DeclStmt *DS = dyn_cast<DeclStmt>(SubStmt)) {
      // The decl statement creates a scope if any of the decls in it are VLAs
      // or have the cleanup attribute.
      for (DeclStmt::decl_iterator I = DS->decl_begin(), E = DS->decl_end();
           I != E; ++I) {
        // If this decl causes a new scope, push and switch to it.
        if (unsigned Diag = GetDiagForGotoScopeDecl(*I, isCPlusPlus)) {
          Scopes.push_back(GotoScope(ParentScope, Diag, (*I)->getLocation()));
          ParentScope = Scopes.size()-1;
        }

        // If the decl has an initializer, walk it with the potentially new
        // scope we just installed.
        if (VarDecl *VD = dyn_cast<VarDecl>(*I))
          if (Expr *Init = VD->getInit())
            BuildScopeInformation(Init, ParentScope);
      }
      continue;
    }

    // Disallow jumps into any part of an @try statement by pushing a scope and
    // walking all sub-stmts in that scope.
    if (ObjCAtTryStmt *AT = dyn_cast<ObjCAtTryStmt>(SubStmt)) {
      // Recursively walk the AST for the @try part.
      Scopes.push_back(GotoScope(ParentScope,diag::note_protected_by_objc_try,
                                 AT->getAtTryLoc()));
      if (Stmt *TryPart = AT->getTryBody())
        BuildScopeInformation(TryPart, Scopes.size()-1);

      // Jump from the catch to the finally or try is not valid.
      for (ObjCAtCatchStmt *AC = AT->getCatchStmts(); AC;
           AC = AC->getNextCatchStmt()) {
        Scopes.push_back(GotoScope(ParentScope,
                                   diag::note_protected_by_objc_catch,
                                   AC->getAtCatchLoc()));
        // @catches are nested and it isn't
        BuildScopeInformation(AC->getCatchBody(), Scopes.size()-1);
      }

      // Jump from the finally to the try or catch is not valid.
      if (ObjCAtFinallyStmt *AF = AT->getFinallyStmt()) {
        Scopes.push_back(GotoScope(ParentScope,
                                   diag::note_protected_by_objc_finally,
                                   AF->getAtFinallyLoc()));
        BuildScopeInformation(AF, Scopes.size()-1);
      }

      continue;
    }

    // Disallow jumps into the protected statement of an @synchronized, but
    // allow jumps into the object expression it protects.
    if (ObjCAtSynchronizedStmt *AS = dyn_cast<ObjCAtSynchronizedStmt>(SubStmt)){
      // Recursively walk the AST for the @synchronized object expr, it is
      // evaluated in the normal scope.
      BuildScopeInformation(AS->getSynchExpr(), ParentScope);

      // Recursively walk the AST for the @synchronized part, protected by a new
      // scope.
      Scopes.push_back(GotoScope(ParentScope,
                                 diag::note_protected_by_objc_synchronized,
                                 AS->getAtSynchronizedLoc()));
      BuildScopeInformation(AS->getSynchBody(), Scopes.size()-1);
      continue;
    }

    // Disallow jumps into any part of a C++ try statement. This is pretty
    // much the same as for Obj-C.
    if (CXXTryStmt *TS = dyn_cast<CXXTryStmt>(SubStmt)) {
      Scopes.push_back(GotoScope(ParentScope, diag::note_protected_by_cxx_try,
                                 TS->getSourceRange().getBegin()));
      if (Stmt *TryBlock = TS->getTryBlock())
        BuildScopeInformation(TryBlock, Scopes.size()-1);

      // Jump from the catch into the try is not allowed either.
      for (unsigned I = 0, E = TS->getNumHandlers(); I != E; ++I) {
        CXXCatchStmt *CS = TS->getHandler(I);
        Scopes.push_back(GotoScope(ParentScope,
                                   diag::note_protected_by_cxx_catch,
                                   CS->getSourceRange().getBegin()));
        BuildScopeInformation(CS->getHandlerBlock(), Scopes.size()-1);
      }

      continue;
    }

    // Recursively walk the AST.
    BuildScopeInformation(SubStmt, ParentScope);
  }
}