r194915 - ObjetiveC ARC. Start diagnosing invalid toll free bridging.

[Douglas Gregor]

On Nov 15, 2013, at 5:45 PM, Fariborz Jahanian <fjahanian at apple.com> wrote:

> Author: fjahanian
> Date: Fri Nov 15 19:45:25 2013
> New Revision: 194915
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=194915&view=rev
> Log:
> ObjetiveC ARC. Start diagnosing invalid toll free bridging.
> // rdar://15454846.
> 
> Modified:
>    cfe/trunk/include/clang/Basic/DiagnosticGroups.td
>    cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>    cfe/trunk/lib/Sema/SemaExprObjC.cpp
>    cfe/trunk/test/SemaObjC/objcbridge-attribute.m
> 
> Modified: cfe/trunk/include/clang/Basic/DiagnosticGroups.td
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticGroups.td?rev=194915&r1=194914&r2=194915&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/Basic/DiagnosticGroups.td (original)
> +++ cfe/trunk/include/clang/Basic/DiagnosticGroups.td Fri Nov 15 19:45:25 2013
> @@ -381,6 +381,8 @@ def AutomaticReferenceCounting : DiagGro
> def ARCRepeatedUseOfWeakMaybe : DiagGroup<"arc-maybe-repeated-use-of-weak">;
> def ARCRepeatedUseOfWeak : DiagGroup<"arc-repeated-use-of-weak",
>                                      [ARCRepeatedUseOfWeakMaybe]>;
> +def ObjCBridge : DiagGroup<"arc-bridge-cast">;
> +

These toll-free bridging annotations don’t actually have anything to do with ARC. The annotations and warnings are just as valid in non-ARC. The only ARC-specific consider I have is to make sure we’re providing the warnings for both normal C-style casts and the ARC bridging casts (e.g., (__bridge NSString *)cfstr). It’s an unfortunate accident of history that both are called “bridging” that caused the confusion :(

> def SelectorTypeMismatch : DiagGroup<"selector-type-mismatch">;
> def Selector : DiagGroup<"selector", [SelectorTypeMismatch]>;
> def Protocol : DiagGroup<"protocol">;
> 
> Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=194915&r1=194914&r2=194915&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
> +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Fri Nov 15 19:45:25 2013
> @@ -2449,6 +2449,8 @@ def err_objc_bridge_not_pointert_to_stru
>   "'objc_bridge' attribute must be applied to a pointer to struct type">;
> def err_objc_bridged_not_interface : Error<
>   "CF object of type %0 is bridged to '%1', which is not an Objective-C class">;
> +def warn_objc_invalid_bridge : Warning<
> +  "%0 bridges to %1, not %2">, InGroup<ObjCBridge>;
> 
> // Function Parameter Semantic Analysis.
> def err_param_with_void_type : Error<"argument may not have 'void' type">;
> 
> Modified: cfe/trunk/lib/Sema/SemaExprObjC.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExprObjC.cpp?rev=194915&r1=194914&r2=194915&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaExprObjC.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaExprObjC.cpp Fri Nov 15 19:45:25 2013
> @@ -3172,23 +3172,32 @@ static bool CheckObjCBridgeCast(Sema &S,
>     if (TDNDecl->hasAttr<ObjCBridgeAttr>()) {
>       ObjCBridgeAttr *ObjCBAttr = TDNDecl->getAttr<ObjCBridgeAttr>();
>       IdentifierInfo *Parm = ObjCBAttr->getBridgedType();
> +      NamedDecl *Target = 0;
>       if (Parm && S.getLangOpts().ObjC1) {
>         // Check for an existing type with this name.
>         LookupResult R(S, DeclarationName(Parm), SourceLocation(),
>                        Sema::LookupOrdinaryName);
>         if (S.LookupName(R, S.TUScope)) {
> -          NamedDecl *Target = R.getFoundDecl();
> -          if (Target && !isa<ObjCInterfaceDecl>(Target)) {
> -            S.Diag(castExpr->getLocStart(), diag::err_objc_bridged_not_interface)
> -                    << castExpr->getType() << Parm->getName();
> -            S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
> -            S.Diag(Target->getLocStart(), diag::note_declared_at);
> +          Target = R.getFoundDecl();
> +          if (Target && isa<ObjCInterfaceDecl>(Target)) {
> +            ObjCInterfaceDecl *ExprClass = cast<ObjCInterfaceDecl>(Target);
> +            if (const ObjCObjectPointerType *InterfacePointerType =
> +                  castType->getAsObjCInterfacePointerType()) {
> +              ObjCInterfaceDecl *CastClass
> +                = InterfacePointerType->getObjectType()->getInterface();
> +              if ((CastClass == ExprClass) || (CastClass && ExprClass->isSuperClassOf(CastClass)))
> +                return true;
> +              S.Diag(castExpr->getLocStart(), diag::warn_objc_invalid_bridge)
> +                << TDNDecl->getName() << Target->getName() << CastClass->getName();

Please pass the actual QualTypes to the diagnostic rather than the StringRefs from getName(). This will make sure the types are properly quoted and desugared in the diagnostic.

	- Doug


> +              return true;
> +            }
>           }
> -        } else {
> -          S.Diag(castExpr->getLocStart(), diag::err_objc_bridged_not_interface)
> -                  << castExpr->getType() << Parm->getName();
> -          S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
>         }
> +        S.Diag(castExpr->getLocStart(), diag::err_objc_bridged_not_interface)
> +        << castExpr->getType() << Parm->getName();
> +        S.Diag(TDNDecl->getLocStart(), diag::note_declared_at);
> +        if (Target)
> +          S.Diag(Target->getLocStart(), diag::note_declared_at);
>       }
>       return true;
>     }
> 
> Modified: cfe/trunk/test/SemaObjC/objcbridge-attribute.m
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjC/objcbridge-attribute.m?rev=194915&r1=194914&r2=194915&view=diff
> ==============================================================================
> --- cfe/trunk/test/SemaObjC/objcbridge-attribute.m (original)
> +++ cfe/trunk/test/SemaObjC/objcbridge-attribute.m Fri Nov 15 19:45:25 2013
> @@ -48,6 +48,8 @@ typedef CFErrorRef1 CFErrorRef2;
> 
> @class NSString;
> 
> -id Test2(CFErrorRef2 cf) {
> -  return (NSString *)cf;
> +void Test2(CFErrorRef2 cf) {
> +  (void)(NSString *)cf; // expected-warning {{CFErrorRef bridges to NSError, not NSString}}
> +  (void)(NSError *)cf; // okay
> +  (void)(MyError*)cf; // okay,
> }
> 
> 
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