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

[jahanian]

In r195066.
- Fariborz

On Nov 18, 2013, at 4:20 PM, Douglas Gregor <dgregor at apple.com> wrote:

> 
> 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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