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Re: [Qemu-devel] [PATCH v4 04/10] qapi: Emit implicit structs in generat
Re: [Qemu-devel] [PATCH v4 04/10] qapi: Emit implicit structs in generated C
Tue, 8 Mar 2016 22:42:43 -0700
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On 03/08/2016 12:09 PM, Markus Armbruster wrote:
>> I think what would sway me over the fence is looking at some of our
>> constructs: for example, qapi-types.py has gen_object() which it now
>> calls recursively. When called directly from visit_object_type(), we
>> have all the pieces; when called from visit_alternate_type(), we have to
>> create a 1-element members array; and when called recursively, we have
>> to manually explode base into the four pieces.
> What could be improved if we changed visit_object_type() to take a
> QAPISchemaObjectType instead of name, info, base, members, variants?
> I believe we'd leave gen_object() unchanged to keep
> visit_alternate_type() simple.
> Here's a different one: we could drop visit_object_type_flat().
Indeed. But I'd rather get v5 of this series out sooner rather than
later, so I'll save the change for a later day.
>>> Uh, these are "always reserved for use as identifiers with file scope"
>>> (C99 7.1.3). I'm afraid we need to use the q_ prefix.
Seems doable. We already reserved q_ for ourselves (commit 9fb081e0), so
far using it mainly by c_name. There's still the risk that c_name adds
q_ onto something ticklish which then clashes with our use of q_ on an
implicit type for something else; except that we haven't declared 'obj'
> I feel awful generating >100KiB of code that gets included pretty much
> every time we compile anything. Perhaps the proper fix for that is to
> find out *why* we include qapi-types.h so much, then figure out how to
> include it much, much less.
> Here's a guilty one: error.h. I believe it includes qapi-types.h just
> for QapiErrorClass. I guess it's only in the QAPI schema to have
> QapiErrorClass_lookup generated. I'd gladly maintain those nine(!)
> lines of code manually if it helps me drop >100KiB of useless code from
> many (most?) compiles.
Commit 13f59ae predates my work on qapi, but I think you're right that
error.h including qapi-types.h is a big offender and appears to do so
solely for ErrorClass. But how about as a followup series, so that v5
gets out the door sooner.
> Another one are builtin QAPI types. A few headers want them. We could
> put them into a separate header instead of generating them into
> qapi-types.h. Could also enable getting rid of the ugly "spew builtins
> into every header, but guard them with #ifdeffery" trick.
In that same series.
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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[Qemu-devel] [PATCH v4 04/10] qapi: Emit implicit structs in generated C, Eric Blake, 2016/03/05
[Qemu-devel] [PATCH v4 01/10] qapi: Assert in places where variants are not handled, Eric Blake, 2016/03/05
[Qemu-devel] [PATCH v4 03/10] qapi: Make c_type() more OO-like, Eric Blake, 2016/03/05
[Qemu-devel] [PATCH v4 02/10] qapi: Fix command with named empty argument type, Eric Blake, 2016/03/05
[Qemu-devel] [PATCH v4 08/10] qapi: Allow anonymous base for flat union, Eric Blake, 2016/03/05
- [Qemu-devel] [PATCH v4 05/10] qapi: Utilize implicit struct visits, (continued)