clang/lib/ARCMigrate/TransARCAssign.cpp

   1 //===--- TransARCAssign.cpp - Transformations to ARC mode -----------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // makeAssignARCSafe:
  10 //
  11 // Add '__strong' where appropriate.
  12 //
  13 //  for (id x in collection) {
  14 //    x = 0;
  15 //  }
  16 // ---->
  17 //  for (__strong id x in collection) {
  18 //    x = 0;
  19 //  }
  20 //
  21 //===----------------------------------------------------------------------===//
  22
  23 #include "Transforms.h"
  24 #include "Internals.h"
  25 #include "clang/AST/ASTContext.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 }