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1 //===--- TransARCAssign.cpp - Transformations 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:
ARCAssignChecker(MigrationPass & pass)40   ARCAssignChecker(MigrationPass &pass) : Pass(pass) { }
41 
VisitBinaryOperator(BinaryOperator * Exp)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 
makeAssignARCSafe(MigrationPass & pass)75 void trans::makeAssignARCSafe(MigrationPass &pass) {
76   ARCAssignChecker assignCheck(pass);
77   assignCheck.TraverseDecl(pass.Ctx.getTranslationUnitDecl());
78 }
79