[cfe-commits] [PATCH] ObjC: interface decls pointing to implementation decls

[steve naroff]

Hey Argyrios,

I really like the idea of moving this association from Sema->ASTContext.

 From my perspective, adding getImplementation to the  
ObjCContainerDecl AST has the following drawbacks:

- The ObjCImplDecl is rarely used. For example Cocoa.h contains ~700  
"containers" that don't have implementations (which include classes,  
categories, and protocols). Even for non-system classes/categories/ 
protocols, the slot would be rarely used as well (since most ObjC  
files/modules contain a very small number of implementations...1 is  
very common).
- The ObjCImplDecl doesn't make sense for protocols (since they don't  
have an implementation).

Did you consider adding the following API to ASTContext?

For example...

ObjCImplementationDecl  
*ASTContext::getImplementation(ObjCInterfaceDecl *);
ObjCCategoryImplDecl *ASTContext::getImplementation(ObjCCategoryDecl *);

ASTContext would use a "Map" to associate the ObjCContainerDecl with  
it's ObjCImplDecl.

snaroff

On Jul 19, 2009, at 9:19 PM, Argyrios Kyrtzidis wrote:

> Hi all,
>
> Currently you can't find the implementation of an interface using only
> the ASTContext. This results in Sema doing name lookups when looking
> for methods or keeping data structures like ObjCCategoryImpls.
> IMO the ASTContext should provide the information that "this
> ObjCIntefaceDecl is implemented by this ObjCImplementationDecl". This
> way Sema gets simplified, it can get at the implementation without
> doing name lookups
> and a client can easily access such information without the need to
> build data structures like Sema's.
>
> I attached 3 patches for your reviewal pleasure:
>
> objc_impl1.patch:  Modifies ObjCContainerDecl so that it can point to
> its implementation. As a bonus, Sema is modified to emit an error when
> a category is reimplemented (previously it didn't emit any  
> diagnostic).
> objc_impl2.patch:  Sema::LookupObjCImplementation() is removed, and
> ObjCInterfaceDecl::getImplementation() is used in its place. No name
> lookups, w00t!
> objc_impl3.patch: The ObjCCategoryImpls vector is removed from Sema,
> and ObjCInterfaceDecl::getCategoryClassMethod() and
> ObjCInterfaceDecl::getCategoryInstanceMethod() are used for the same
> functionality.
>
> Let me know what you think.
>
> -Argiris
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