[cfe-commits] r93271 - in /cfe/trunk: lib/Sema/Sema.h lib/Sema/SemaExpr.cpp test/SemaObjC/ivar-lookup-resolution-builtin.m

[Douglas Gregor]

On Jan 12, 2010, at 3:58 PM, Fariborz Jahanian wrote:

> Author: fjahanian
> Date: Tue Jan 12 17:58:59 2010
> New Revision: 93271
>
> URL: http://llvm.org/viewvc/llvm-project?rev=93271&view=rev
> Log:
> When in objective-c methods, do the built-in name lookup after
> ivar name lookup. Fixes pr5986.
>
> Added:
>    cfe/trunk/test/SemaObjC/ivar-lookup-resolution-builtin.m
> Modified:
>    cfe/trunk/lib/Sema/Sema.h
>    cfe/trunk/lib/Sema/SemaExpr.cpp
>
> Modified: cfe/trunk/lib/Sema/Sema.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/Sema.h?rev=93271&r1=93270&r2=93271&view=diff
>
> =
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> ======================================================================
> --- cfe/trunk/lib/Sema/Sema.h (original)
> +++ cfe/trunk/lib/Sema/Sema.h Tue Jan 12 17:58:59 2010
> @@ -1481,7 +1481,8 @@
>
>   OwningExprResult LookupInObjCMethod(LookupResult &R,
>                                       Scope *S,
> -                                      IdentifierInfo *II);
> +                                      IdentifierInfo *II,
> +                                      bool  
> AllowBuiltinCreation=false);
>
>   OwningExprResult ActOnDependentIdExpression(const CXXScopeSpec &SS,
>                                               DeclarationName Name,
>
> Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=93271&r1=93270&r2=93271&view=diff
>
> = 
> = 
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> ======================================================================
> --- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaExpr.cpp Tue Jan 12 17:58:59 2010
> @@ -1033,12 +1033,13 @@
>     // Just re-use the lookup done by isTemplateName.
>     DecomposeTemplateName(R, Id);
>   } else {
> -    LookupParsedName(R, S, &SS, true);
> +    bool IvarLookupFollowUp = (!SS.isSet() && II && getCurMethodDecl 
> ());
> +    LookupParsedName(R, S, &SS, !IvarLookupFollowUp);
>
>     // If this reference is in an Objective-C method, then we need  
> to do
>     // some special Objective-C lookup, too.
> -    if (!SS.isSet() && II && getCurMethodDecl()) {
> -      OwningExprResult E(LookupInObjCMethod(R, S, II));
> +    if (IvarLookupFollowUp) {
> +      OwningExprResult E(LookupInObjCMethod(R, S, II, true));
>       if (E.isInvalid())
>         return ExprError();
>
> @@ -1218,7 +1219,8 @@
> /// Returns a null sentinel to indicate trivial success.
> Sema::OwningExprResult
> Sema::LookupInObjCMethod(LookupResult &Lookup, Scope *S,
> -                         IdentifierInfo *II) {
> +                         IdentifierInfo *II,
> +                         bool AllowBuiltinCreation) {
>   SourceLocation Loc = Lookup.getNameLoc();
>
>   // There are two cases to handle here.  1) scoped lookup could  
> have failed,
> @@ -1299,7 +1301,18 @@
>       T = Context.getObjCClassType();
>     return Owned(new (Context) ObjCSuperExpr(Loc, T));
>   }
> -
> +  if (Lookup.empty() && II && AllowBuiltinCreation) {
> +    // FIXME. Consolidate this with similar code in LookupName.
> +    if (unsigned BuiltinID = II->getBuiltinID()) {
> +      if (!(getLangOptions().CPlusPlus &&
> +            Context.BuiltinInfo.isPredefinedLibFunction 
> (BuiltinID))) {
> +        NamedDecl *D = LazilyCreateBuiltin((IdentifierInfo *)II,  
> BuiltinID,
> +                                           S,  
> Lookup.isForRedeclaration(),
> +                                           Lookup.getNameLoc());
> +        if (D) Lookup.addDecl(D);
> +      }
> +    }
> +  }
>   // Sentinel value saying that we didn't do anything special.
>   return Owned((Expr*) 0);
> }

C++ has a cleaner way of handling lookup for its data members, e.g.,

   struct X {
     int member;
     int getMember() { return member; }
   };

C++ actually walks the Scope chain upward, and checks for each Scope  
whether it has an Entity (which is a DeclContext). For entities that  
are C++ member functions (like X::getMember()), it then performs  
lookup into the class type (X), its base classes, and so on.

Now, the C++ implementation is slower than just checking the  
identifier chain, but it would make sense to take this slower path  
when we know we're in an Objective-C method (getCurMethodDecl() != 0).  
That would unify the name-lookup logic for Objective-C and C++  
somewhat, which is good for Objective-C++ and also would probably  
address

	http://llvm.org/bugs/show_bug.cgi?id=5984

   - Doug