[cfe-dev] Fixing MemberPointerTypeLoc.

[Abramo Bagnara]

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.