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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/Sema/SemaDiagnostic.h"
     27 
     28 using namespace clang;
     29 using namespace arcmt;
     30 using namespace trans;
     31 
     32 namespace {
     33 
     34 class ARCAssignChecker : public RecursiveASTVisitor<ARCAssignChecker> {
     35   MigrationPass &Pass;
     36   llvm::DenseSet<VarDecl *> ModifiedVars;
     37 
     38 public:
     39   ARCAssignChecker(MigrationPass &pass) : Pass(pass) { }
     40 
     41   bool VisitBinaryOperator(BinaryOperator *Exp) {
     42     if (Exp->getType()->isDependentType())
     43       return true;
     44 
     45     Expr *E = Exp->getLHS();
     46     SourceLocation OrigLoc = E->getExprLoc();
     47     SourceLocation Loc = OrigLoc;
     48     DeclRefExpr *declRef = dyn_cast<DeclRefExpr>(E->IgnoreParenCasts());
     49     if (declRef && isa<VarDecl>(declRef->getDecl())) {
     50       ASTContext &Ctx = Pass.Ctx;
     51       Expr::isModifiableLvalueResult IsLV = E->isModifiableLvalue(Ctx, &Loc);
     52       if (IsLV != Expr::MLV_ConstQualified)
     53         return true;
     54       VarDecl *var = cast<VarDecl>(declRef->getDecl());
     55       if (var->isARCPseudoStrong()) {
     56         Transaction Trans(Pass.TA);
     57         if (Pass.TA.clearDiagnostic(diag::err_typecheck_arr_assign_enumeration,
     58                                     Exp->getOperatorLoc())) {
     59           if (!ModifiedVars.count(var)) {
     60             TypeLoc TLoc = var->getTypeSourceInfo()->getTypeLoc();
     61             Pass.TA.insert(TLoc.getBeginLoc(), "__strong ");
     62             ModifiedVars.insert(var);
     63           }
     64         }
     65       }
     66     }
     67 
     68     return true;
     69   }
     70 };
     71 
     72 } // anonymous namespace
     73 
     74 void trans::makeAssignARCSafe(MigrationPass &pass) {
     75   ARCAssignChecker assignCheck(pass);
     76   assignCheck.TraverseDecl(pass.Ctx.getTranslationUnitDecl());
     77 }
     78