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 using llvm::StringRef;
  31
  32 namespace {
  33
  34 class UnusedInitRewriter : public RecursiveASTVisitor<UnusedInitRewriter> {
  35   Stmt *Body;
  36   MigrationPass &Pass;
  37
  38   ExprSet Removables;
  39
  40 public:
  41   UnusedInitRewriter(MigrationPass &pass)
  42     : Body(0), Pass(pass) { }
  43
  44   void transformBody(Stmt *body) {
  45     Body = body;
  46     collectRemovables(body, Removables);
  47     TraverseStmt(body);
  48   }
  49
  50   bool VisitObjCMessageExpr(ObjCMessageExpr *ME) {
  51     if (ME->isDelegateInitCall() &&
  52         isRemovable(ME) &&
  53         Pass.TA.hasDiagnostic(diag::err_arc_unused_init_message,
  54                               ME->getExprLoc())) {
  55       Transaction Trans(Pass.TA);
  56       Pass.TA.clearDiagnostic(diag::err_arc_unused_init_message,
  57                               ME->getExprLoc());
  58       Pass.TA.insert(ME->getExprLoc(), "self = ");
  59     }
  60     return true;
  61   }
  62
  63 private:
  64   bool isRemovable(Expr *E) const {
  65     return Removables.count(E);
  66   }
  67 };
  68
  69 } // anonymous namespace
  70
  71 void trans::rewriteUnusedInitDelegate(MigrationPass &pass) {
  72   BodyTransform<UnusedInitRewriter> trans(pass);
  73   trans.TraverseDecl(pass.Ctx.getTranslationUnitDecl());
  74 }