Objective-C: Provide fixit hints when warning

about 'isa' ivar being explicitely accessed
when base is a user class object reference.
// rdar://13503456


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178562 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 34 insertions, 6 deletions

diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index c1d86550a5..5459d74016 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -456,7 +456,8 @@ static void CheckForNullPointerDereference(Sema &S, Expr *E) {
 }
 
 static void DiagnoseDirectIsaAccess(Sema &S, const ObjCIvarRefExpr *OIRE,
-                                    bool IsAssign) {
+                                    SourceLocation AssignLoc,
+                                    const Expr* RHS) {
   const ObjCIvarDecl *IV = OIRE->getDecl();
   if (!IV)
     return;
@@ -476,8 +477,35 @@ static void DiagnoseDirectIsaAccess(Sema &S, const ObjCIvarRefExpr *OIRE,
       ObjCIvarDecl *IV = IDecl->lookupInstanceVariable(Member, ClassDeclared);
       if (!ClassDeclared->getSuperClass()
           && (*ClassDeclared->ivar_begin()) == IV) {
-        S.Diag(OIRE->getLocation(), IsAssign ? diag::warn_objc_isa_assign
-                                             : diag::warn_objc_isa_use);
+        if (RHS) {
+          NamedDecl *ObjectSetClass =
+            S.LookupSingleName(S.TUScope,
+                               &S.Context.Idents.get("object_setClass"),
+                               SourceLocation(), S.LookupOrdinaryName);
+          if (ObjectSetClass) {
+            SourceLocation RHSLocEnd = S.PP.getLocForEndOfToken(RHS->getLocEnd());
+            S.Diag(OIRE->getExprLoc(), diag::warn_objc_isa_assign) <<
+            FixItHint::CreateInsertion(OIRE->getLocStart(), "object_setClass(") <<
+            FixItHint::CreateReplacement(SourceRange(OIRE->getOpLoc(),
+                                                     AssignLoc), ",") <<
+            FixItHint::CreateInsertion(RHSLocEnd, ")");
+          }
+          else
+            S.Diag(OIRE->getLocation(), diag::warn_objc_isa_assign);
+        } else {
+          NamedDecl *ObjectGetClass =
+            S.LookupSingleName(S.TUScope,
+                               &S.Context.Idents.get("object_getClass"),
+                               SourceLocation(), S.LookupOrdinaryName);
+          if (ObjectGetClass)
+            S.Diag(OIRE->getExprLoc(), diag::warn_objc_isa_use) <<
+            FixItHint::CreateInsertion(OIRE->getLocStart(), "object_getClass(") <<
+            FixItHint::CreateReplacement(
+                                         SourceRange(OIRE->getOpLoc(),
+                                                     OIRE->getLocEnd()), ")");
+          else
+            S.Diag(OIRE->getLocation(), diag::warn_objc_isa_use);
+        }
         S.Diag(IV->getLocation(), diag::note_ivar_decl);
       }
     }
@@ -538,7 +566,7 @@ ExprResult Sema::DefaultLvalueConversion(Expr *E) {
   }
   else if (const ObjCIvarRefExpr *OIRE =
             dyn_cast<ObjCIvarRefExpr>(E->IgnoreParenCasts()))
-    DiagnoseDirectIsaAccess(*this, OIRE, false);
+    DiagnoseDirectIsaAccess(*this, OIRE, SourceLocation(), /* Expr*/0);
   
   // C++ [conv.lval]p1:
   //   [...] If T is a non-class type, the type of the prvalue is the
@@ -2104,7 +2132,7 @@ Sema::LookupInObjCMethod(LookupResult &Lookup, Scope *S,
         Diag(Loc, diag::warn_direct_ivar_access) << IV->getDeclName();
 
       ObjCIvarRefExpr *Result = new (Context) ObjCIvarRefExpr(IV, IV->getType(),
-                                                              Loc,
+                                                              Loc, IV->getLocation(),
                                                               SelfExpr.take(),
                                                               true, true);
 
@@ -8628,7 +8656,7 @@ ExprResult Sema::CreateBuiltinBinOp(SourceLocation OpLoc,
   }
   else if (const ObjCIvarRefExpr *OIRE =
            dyn_cast<ObjCIvarRefExpr>(LHS.get()->IgnoreParenCasts()))
-    DiagnoseDirectIsaAccess(*this, OIRE, true);
+    DiagnoseDirectIsaAccess(*this, OIRE, OpLoc, RHS.get());
   
   if (CompResultTy.isNull())
     return Owned(new (Context) BinaryOperator(LHS.take(), RHS.take(), Opc,