contrib/llvm/tools/clang/lib/ARCMigrate/TransUnusedInitDelegate.cpp

   1 //===--- TransUnusedInitDelegate.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 // Transformations:
  10 //===----------------------------------------------------------------------===//
  11 //
  12 // rewriteUnusedInitDelegate:
  13 //
  14 // Rewrites an unused result of calling a delegate initialization, to assigning
  15 // the result to self.
  16 // e.g
  17 //  [self init];
  18 // ---->
  19 //  self = [self init];
  20 //
  21 //===----------------------------------------------------------------------===//
  22
  23 #include "Transforms.h"
  24 #include "Internals.h"
  25 #include "clang/Sema/SemaDiagnostic.h"
  26
  27 using namespace clang;
  28 using namespace arcmt;
  29 using namespace trans;
  30
  31 namespace {
  32
  33 class UnusedInitRewriter : public RecursiveASTVisitor<UnusedInitRewriter> {
  34   Stmt *Body;
  35   MigrationPass &Pass;
  36
  37   ExprSet Removables;
  38
  39 public:
  40   UnusedInitRewriter(MigrationPass &pass)
  41     : Body(0), Pass(pass) { }
  42
  43   void transformBody(Stmt *body) {
  44     Body = body;
  45     collectRemovables(body, Removables);
  46     TraverseStmt(body);
  47   }
  48
  49   bool VisitObjCMessageExpr(ObjCMessageExpr *ME) {
  50     if (ME->isDelegateInitCall() &&
  51         isRemovable(ME) &&
  52         Pass.TA.hasDiagnostic(diag::err_arc_unused_init_message,
  53                               ME->getExprLoc())) {
  54       Transaction Trans(Pass.TA);
  55       Pass.TA.clearDiagnostic(diag::err_arc_unused_init_message,
  56                               ME->getExprLoc());
  57       Pass.TA.insert(ME->getExprLoc(), "self = ");
  58     }
  59     return true;
  60   }
  61
  62 private:
  63   bool isRemovable(Expr *E) const {
  64     return Removables.count(E);
  65   }
  66 };
  67
  68 } // anonymous namespace
  69
  70 void trans::rewriteUnusedInitDelegate(MigrationPass &pass) {
  71   BodyTransform<UnusedInitRewriter> trans(pass);
  72   trans.TraverseDecl(pass.Ctx.getTranslationUnitDecl());
  73 }