[cfe-dev] Fixing MemberPointerTypeLoc.

[Douglas Gregor]

On Mar 4, 2011, at 11:22 AM, Abramo Bagnara wrote:

> Il 04/03/2011 20:03, Douglas Gregor ha scritto:
>> 
>> On Mar 4, 2011, at 10:42 AM, Enea Zaffanella wrote:
>> 
>>> Il 04/03/2011 19:31, Douglas Gregor ha scritto:
>>>> 
>>>> On Mar 4, 2011, at 10:23 AM, Abramo Bagnara wrote:
>>>> 
>>>>> Il 04/03/2011 16:20, Douglas Gregor ha scritto:
>>>>>> 
>>>>>> On Mar 4, 2011, at 2:24 AM, Enea Zaffanella wrote:
>>>>>> 
>>>>>>> Hello.
>>>>>>> 
>>>>>>> We would like to get rid of the FIXME in MemberPointerTypeLoc so as to
>>>>>>> provide appropriate NNSLoc info. As an example of the current problem,
>>>>>>> code such as the following:
>>>>>>> 
>>>>>>> int S<int[2+3]>::* ptr = 0;
>>>>>>> 
>>>>>>> gets printed as follows (note that the array size is computed):
>>>>>>> 
>>>>>>> int S<int [5]>::*ptr = 0;
>>>>>>> 
>>>>>>> The situation seems to be much like that of ElaboratedTypeLoc, except
>>>>>>> for the fact that in ElaboratedType we do have an NestedNameSpecifier,
>>>>>>> while in MemberPointerType we have instead
>>>>>>> 
>>>>>>> /// The class of which the pointee is a member. Must ultimately be a
>>>>>>> /// RecordType, but could be a typedef or a template parameter too.
>>>>>>> const Type *Class;
>>>>>>> 
>>>>>>> 
>>>>>>> So, what would be the best way to proceed?
>>>>>>> 
>>>>>>> Can we _add_ a NNS* to MemberPointerType?
>>>>>>> 
>>>>>>> Should we _replace_ the Type* with the NNS* and have the method
>>>>>>> getClass() recompute the class type on the fly?
>>>>>> 
>>>>>> I think this is the best option, since it allows us to represent the source accurately without making MemberPointerType larger. Thanks for working on this!
>>>>> 
>>>>> In theory it was the best options, but to recompute the class type
>>>>> inside getClass() we definitely need to have the ASTContext, right?
>>>> 
>>>> 
>>>> Do we?
>>>> 
>>>> The nested-name-specifier will have to have, as its last component, a Type*. Isn't that what we want from getClass()?
>>>> 
>>>> 	- Doug
>>> 
>>> Basically, we would need to move this code chunk from SemaType.cpp into
>>> the getClass() method of MemberPointerType:
>>> 
>>> QualType ClsType = QualType(NNS->getAsType(), 0);
>>> 
>>> // Note: if NNS is dependent, then its prefix (if any) is already
>>> // included in ClsType; this does not hold if ClsNNS is
>>> // nondependent: in this case (if there is indeed a prefix)
>>> // ClsType needs to be wrapped into an elaborated type.
>>> NestedNameSpecifier *NNSPrefix = NNS->getPrefix();
>>> if (NNSPrefix && !NNS->isDependent())
>>>   ClsType = Context.getElaboratedType(ETK_None, NNSPrefix, ClsType);
>> 
>> 
>> So, it seems like this code is trying to make sure that the
>> nested-name-specifier is already encoded within the class type of the
>> MemberPointerType. If that's the case, why can't we just have TypeLoc
>> information for the class type within MemberPointerTypeLoc?
> 
> Sorry, I'm not sure to understand: in what is different this solution from
> 
>> 2) add a TypeSourceInfo* for the class type to the MemberPointerTypeLoc
> 
> ?
> 
> This is what currently is done for TypeOfTypeLoc.


It's.... not different at all. Sorry, I'm distracted by the deluge of bugs :)

	- Doug