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Re: [cxx-conversion] Convert vec.[ch] to C++ [2/3] (issue6236043)
On Thu, May 24, 2012 at 3:24 AM, Richard Guenther
<richard.guenther@gmail.com> wrote:
> On Wed, May 23, 2012 at 9:49 PM, Diego Novillo <dnovillo@google.com> wrote:
>>
>> Part 2 of the VEC C++ conversion. ?This patch implements the gengtype
>> changes.
>>
>> I extended gengtype to understand templated types. ?These changes are
>> not as ugly as I thought they would be. ?Gengtype has some hardwired
>> knowledge of VEC_*, which I renamed to vec_t. ?I'm not even sure why
>> gengtype needs to care about vec_t in this way, but I was looking for
>> minimal changes, so I just did it.
>>
>> The other change is more generic. ?It allows gengtype to deal with
>> templated types. ?There is a new function (filter_type_name) that
>> recognizes C++ special characters '<', '>' and ':'. ?It turns them
>> into '_'. ?This way, gengtype can generate a valid identifier for the
>> pre-processor. ?It only does this in contexts where it needs a
>> pre-processor identifier. ?For everything else, it emits the type
>> directly. ?So, the functions emitted in gt-*.h files have proper
>> template type references.
>
> This is, of course, just a replacement of special-case handling for vec.h
> with another special-case handling. ?It does not show us how templated
> structs should work with gengtype in general. ?And no, I don't think
> gengtype should keep the special-case for vec.h.
>
> The point was to make all the gt_ggc_* functions function template
> specializations so the code gengtype emits for walking a structs fields
> would be just
>
> ? mark (field1);
> ? mark (field2);
> ?...
>
> and we could manually provide specializations for selected types
> (well, the templates). ?Add a GTY((template)) marker to make gengtype
> not emit the specializations itself (or simply make it recognize template
> types and do nothing for them).
True, but as a preliminary step (and a member of a series of patches), it does
make sense and is good to have.
-- Gaby