Richard Biener <[email protected]> writes:
>> Am 17.08.2023 um 13:25 schrieb Richard Sandiford via Gcc-patches
>> <[email protected]>:
>>
>> Joseph Myers <[email protected]> writes:
>>>> On Wed, 16 Aug 2023, Richard Sandiford via Gcc-patches wrote:
>>>>
>>>> Would it be OK to add support for:
>>>>
>>>> [[__extension__ ...]]
>>>>
>>>> to suppress the pedwarn about using [[]] prior to C2X? Then we can
>>>
>>> That seems like a plausible feature to add.
>>
>> Thanks. Of course, once I actually tried it, I hit a snag:
>> :: isn't a single lexing token prior to C2X, and so something like:
>>
>> [[__extension__ arm::streaming]]
>>
>> would not be interpreted as a scoped attribute in C11. The patch
>> gets around that by allowing two colons in place of :: when
>> __extension__ is used. I realise that's pushing the bounds of
>> acceptability though...
>>
>> I wondered about trying to require the two colons to be immediately
>> adjacent. But:
>>
>> (a) There didn't appear to be an existing API to check that, which seemed
>> like a red flag. The closest I could find was get_source_text_between.
>
> IStR a cop Toben has ->prev_white or so
Ah, thanks.
if (c_parser_next_token_is (parser, CPP_SCOPE)
|| (loose_scope_p
&& c_parser_next_token_is (parser, CPP_COLON)
&& c_parser_peek_2nd_token (parser)->type == CPP_COLON
&& !(c_parser_peek_2nd_token (parser)->flags & PREV_WHITE)))
seems to work for (i.e. reject):
typedef int [[__extension__ gnu : : vector_size (4)]] g3;
typedef int [[__extension__ gnu :/**/: vector_size (4)]] g13;
but not:
#define BAR :
typedef int [[__extension__ gnu BAR BAR vector_size (4)]] g5;
#define JOIN(A, B) A/**/B
typedef int [[__extension__ gnu JOIN(:,:) vector_size (4)]] g14;
I now realise the patch was peeking at the wrong token. Will fix,
and add more tests.
Richard
