llvm dev - Feb 2016 - Question about __NSConstantString and __NSConstantString_tag

> On Feb 19, 2016, at 7:16 AM, Brad King <brad.king at kitware.com>
wrote:
> 
> On 02/18/2016 05:51 PM, Michka Popoff wrote:
>> Our problem is that the AST contains some declarations which were not
there before.
> [snip]
>> __NSConstantString and __NSConstantString_tag are now exposed.
> [snip]
>> Maybe someone could enlighten us about this change.
>> If it’s not a bug, we would like to know more about these structures.
This struct/typedef are for __builtin___CFStringMakeConstantString (and the NS
variant) and are predefined to make these builtins behave correctly with
modules.  Adding them was intentional :-)
> 
> To clarify, this is not so much about the appearance of new builtins
> but that the structure has fields with no name.  Other builtin
> structures like __va_list_tag have names on their fields.  FieldDecl
> derives (indirectly) from NamedDecl.
> 
> Our concern is that AST processing tools expect to find a name on
> fields, and the changes in question introduced fields without names.
> Can they be given names, if only for AST consistency?
Yes, sounds like a good idea. I’ll take a look at this later today.
> 
> Thanks,
> -Brad
>

On 02/19/2016 10:35 AM, Ben Langmuir wrote:
>> On Feb 19, 2016, at 7:16 AM, Brad King wrote:
>> [snip]
>>> __NSConstantString and __NSConstantString_tag are now exposed.
>> To clarify, this is not so much about the appearance of new builtins
>> but that the structure has fields with no name.  Other builtin
>> structures like __va_list_tag have names on their fields.  FieldDecl
>> derives (indirectly) from NamedDecl.
>>
>> Our concern is that AST processing tools expect to find a name on
>> fields, and the changes in question introduced fields without names.
>> Can they be given names, if only for AST consistency?
> 
> Yes, sounds like a good idea. I’ll take a look at this later today.
Here is a patch that adds the field names.

Thanks,
-Brad

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> On Feb 25, 2016, at 7:49 AM, Brad King <brad.king at kitware.com>
wrote:
> 
> On 02/19/2016 10:35 AM, Ben Langmuir wrote:
>>> On Feb 19, 2016, at 7:16 AM, Brad King wrote:
>>> [snip]
>>>> __NSConstantString and __NSConstantString_tag are now exposed.
>>> To clarify, this is not so much about the appearance of new
builtins
>>> but that the structure has fields with no name.  Other builtin
>>> structures like __va_list_tag have names on their fields. 
FieldDecl
>>> derives (indirectly) from NamedDecl.
>>> 
>>> Our concern is that AST processing tools expect to find a name on
>>> fields, and the changes in question introduced fields without
names.
>>> Can they be given names, if only for AST consistency?
>> 
>> Yes, sounds like a good idea. I’ll take a look at this later today.
> 
> Here is a patch that adds the field names.
> 
> Thanks,
> -Brad
> 
> <0001-Populate-field-names-on-builtin-struct-underlying-__.patch>
I’m really sorry I totally forgot about this!  Thanks for the patch.  Committed
as r261887