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      1 //===--- TransARCAssign.cpp - Tranformations to ARC mode ------------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // makeAssignARCSafe:
     11 //
     12 // Add '__strong' where appropriate.
     13 //
     14 //  for (id x in collection) {
     15 //    x = 0;
     16 //  }
     17 // ---->
     18 //  for (__strong id x in collection) {
     19 //    x = 0;
     20 //  }
     21 //
     22 //===----------------------------------------------------------------------===//
     23 
     24 #include "Transforms.h"
     25 #include "Internals.h"
     26 #include "clang/AST/ASTContext.h"
     27 #include "clang/Sema/SemaDiagnostic.h"
     28 
     29 using namespace clang;
     30 using namespace arcmt;
     31 using namespace trans;
     32 
     33 namespace {
     34 
     35 class ARCAssignChecker : public RecursiveASTVisitor<ARCAssignChecker> {
     36   MigrationPass &Pass;
     37   llvm::DenseSet<VarDecl *> ModifiedVars;
     38 
     39 public:
     40   ARCAssignChecker(MigrationPass &pass) : Pass(pass) { }
     41 
     42   bool VisitBinaryOperator(BinaryOperator *Exp) {
     43     if (Exp->getType()->isDependentType())
     44       return true;
     45 
     46     Expr *E = Exp->getLHS();
     47     SourceLocation OrigLoc = E->getExprLoc();
     48     SourceLocation Loc = OrigLoc;
     49     DeclRefExpr *declRef = dyn_cast<DeclRefExpr>(E->IgnoreParenCasts());
     50     if (declRef && isa<VarDecl>(declRef->getDecl())) {
     51       ASTContext &Ctx = Pass.Ctx;
     52       Expr::isModifiableLvalueResult IsLV = E->isModifiableLvalue(Ctx, &Loc);
     53       if (IsLV != Expr::MLV_ConstQualified)
     54         return true;
     55       VarDecl *var = cast<VarDecl>(declRef->getDecl());
     56       if (var->isARCPseudoStrong()) {
     57         Transaction Trans(Pass.TA);
     58         if (Pass.TA.clearDiagnostic(diag::err_typecheck_arr_assign_enumeration,
     59                                     Exp->getOperatorLoc())) {
     60           if (!ModifiedVars.count(var)) {
     61             TypeLoc TLoc = var->getTypeSourceInfo()->getTypeLoc();
     62             Pass.TA.insert(TLoc.getBeginLoc(), "__strong ");
     63             ModifiedVars.insert(var);
     64           }
     65         }
     66       }
     67     }
     68 
     69     return true;
     70   }
     71 };
     72 
     73 } // anonymous namespace
     74 
     75 void trans::makeAssignARCSafe(MigrationPass &pass) {
     76   ARCAssignChecker assignCheck(pass);
     77   assignCheck.TraverseDecl(pass.Ctx.getTranslationUnitDecl());
     78 }
     79