[arcmt] At an unbridged cast error, if we're returning a load-of-ivar from a +0 method,

automatically insert a __bridge cast.

radar://11560638

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@158127 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 32 insertions, 7 deletions

diff --git a/lib/ARCMigrate/TransAutoreleasePool.cpp b/lib/ARCMigrate/TransAutoreleasePool.cpp
index 87877242a1..f0db4d024d 100644
--- a/lib/ARCMigrate/TransAutoreleasePool.cpp
+++ b/lib/ARCMigrate/TransAutoreleasePool.cpp
@@ -75,7 +75,7 @@ public:
                                                  &pass.Ctx.Idents.get("drain"));
   }
 
-  void transformBody(Stmt *body) {
+  void transformBody(Stmt *body, Decl *ParentD) {
     Body = body;
     TraverseStmt(body);
   }
diff --git a/lib/ARCMigrate/TransRetainReleaseDealloc.cpp b/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
index df3cd5858e..b8a84ec5b8 100644
--- a/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
+++ b/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
@@ -49,7 +49,7 @@ public:
         Pass.Ctx.Selectors.getNullarySelector(&Pass.Ctx.Idents.get("finalize"));
   }
 
-  void transformBody(Stmt *body) {
+  void transformBody(Stmt *body, Decl *ParentD) {
     Body = body;
     collectRemovables(body, Removables);
     StmtMap.reset(new ParentMap(body));
diff --git a/lib/ARCMigrate/TransUnbridgedCasts.cpp b/lib/ARCMigrate/TransUnbridgedCasts.cpp
index 37cebc9e3a..72c0d8e7de 100644
--- a/lib/ARCMigrate/TransUnbridgedCasts.cpp
+++ b/lib/ARCMigrate/TransUnbridgedCasts.cpp
@@ -50,13 +50,15 @@ class UnbridgedCastRewriter : public RecursiveASTVisitor<UnbridgedCastRewriter>{
   MigrationPass &Pass;
   IdentifierInfo *SelfII;
   OwningPtr<ParentMap> StmtMap;
+  Decl *ParentD;
 
 public:
-  UnbridgedCastRewriter(MigrationPass &pass) : Pass(pass) {
+  UnbridgedCastRewriter(MigrationPass &pass) : Pass(pass), ParentD(0) {
     SelfII = &Pass.Ctx.Idents.get("self");
   }
 
-  void transformBody(Stmt *body) {
+  void transformBody(Stmt *body, Decl *ParentD) {
+    this->ParentD = ParentD;
     StmtMap.reset(new ParentMap(body));
     TraverseStmt(body);
   }
@@ -155,6 +157,21 @@ private:
         }
       }
     }
+
+    // If returning an ivar or a member of an ivar from a +0 method, use
+    // a __bridge cast.
+    Expr *base = inner->IgnoreParenImpCasts();
+    while (isa<MemberExpr>(base))
+      base = cast<MemberExpr>(base)->getBase()->IgnoreParenImpCasts();
+    if (isa<ObjCIvarRefExpr>(base) &&
+        isa<ReturnStmt>(StmtMap->getParentIgnoreParenCasts(E))) {
+      if (ObjCMethodDecl *method = dyn_cast_or_null<ObjCMethodDecl>(ParentD)) {
+        if (!method->hasAttr<NSReturnsRetainedAttr>()) {
+          castToObjCObject(E, /*retained=*/false);
+          return;
+        }
+      }
+    }
   }
 
   void castToObjCObject(CastExpr *E, bool retained) {
diff --git a/lib/ARCMigrate/TransUnusedInitDelegate.cpp b/lib/ARCMigrate/TransUnusedInitDelegate.cpp
index 60ed32aef4..7a825e8165 100644
--- a/lib/ARCMigrate/TransUnusedInitDelegate.cpp
+++ b/lib/ARCMigrate/TransUnusedInitDelegate.cpp
@@ -40,7 +40,7 @@ public:
   UnusedInitRewriter(MigrationPass &pass)
     : Body(0), Pass(pass) { }
 
-  void transformBody(Stmt *body) {
+  void transformBody(Stmt *body, Decl *ParentD) {
     Body = body;
     collectRemovables(body, Removables);
     TraverseStmt(body);
diff --git a/lib/ARCMigrate/Transforms.h b/lib/ARCMigrate/Transforms.h
index 7abc0304b1..5d4ac94460 100644
--- a/lib/ARCMigrate/Transforms.h
+++ b/lib/ARCMigrate/Transforms.h
@@ -13,6 +13,7 @@
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/AST/ParentMap.h"
 #include "llvm/ADT/DenseSet.h"
+#include "llvm/Support/SaveAndRestore.h"
 
 namespace clang {
   class Decl;
@@ -176,15 +177,22 @@ StringRef getNilString(ASTContext &Ctx);
 template <typename BODY_TRANS>
 class BodyTransform : public RecursiveASTVisitor<BodyTransform<BODY_TRANS> > {
   MigrationPass &Pass;
+  Decl *ParentD;
 
+  typedef RecursiveASTVisitor<BodyTransform<BODY_TRANS> > base;
 public:
-  BodyTransform(MigrationPass &pass) : Pass(pass) { }
+  BodyTransform(MigrationPass &pass) : Pass(pass), ParentD(0) { }
 
   bool TraverseStmt(Stmt *rootS) {
     if (rootS)
-      BODY_TRANS(Pass).transformBody(rootS);
+      BODY_TRANS(Pass).transformBody(rootS, ParentD);
     return true;
   }
+
+  bool TraverseObjCMethodDecl(ObjCMethodDecl *D) {
+    SaveAndRestore<Decl *> SetParent(ParentD, D);
+    return base::TraverseObjCMethodDecl(D);
+  }
 };
 
 typedef llvm::DenseSet<Expr *> ExprSet;