[cfe-dev] Patch for IdentifierResolver

[Chris Lattner]

On Apr 14, 2008, at 11:40 AM, Steve Naroff wrote:
>> the parser produces one top-level ScopedDecl (or one DeclStmt) with  
>> the
>> first decl and you can get the others through decl- 
>> >getNextDeclarator().
>> Seems to make sense to me. However, this is only useful for  
>> TypedefDecl
>> and File/BlockVarDecl, is this correct ?
>
> That's true. The NextDeclarator field isn't used for ParmVarDecl.  
> Note that we don't instantiate a ParmVarDecl for function prototypes  
> (as a result, we do loose the name if provided). If we did, removing  
> this field would save some space.

Actually, we do now instantiate ParmVarDecl for function prototypes.   
This is required to handle prototypes like this correctly:
   int foo(int x, int A[x]);

>> How about having MultiTypedefDecl, MultiFileVarDecl and
>> MultiBlockVarDecl, like this:
>>
>> class MultiTypedefDecl : public TypedefDecl, public MultiDeclarator {
>>
>> only used for multi declarations ? MultiDeclarator will contain
>> getNextDeclarator().
>>
>
> I don't think this relationship is interesting enough to call out in  
> the hierarchy. In fact, after speaking briefly with Chris, it might  
> be nice to consider removing the NextDeclarator field entirely. We  
> could make the list a responsibility of the client. For example, we  
> could change FunctionDecl to maintain the decl list explicitly. If  
> we did this, we could unify iteration with parameters (which would  
> simplify the API).

To reiterate, I really don't think we need to preserve  
'NextDeclarator'.  There is no current client of it (AFAIK), and there  
are more efficient ways to represent it if we ever need it in the  
future.

>> And BTW, now that there is a DeclContext, how about merging
>> File/BlockVarDecl into a single VarDecl ?
>
> When you added DeclContext, this was my thought as well.  
> Unfortunately, I was unable to come up with a benefit (other than  
> removing a class). I don't believe it simplifies the code or saves  
> any space (especially since we still need ParmVarDecl).

I think a simplified Decl class hierarchy is a win!

-Chris