On 02/18/2016 06:58 AM, Markus Armbruster wrote: > Eric Blake <ebl...@redhat.com> writes: > >> We initially created the static visit_type_FOO_fields() helper >> function for reuse of code - we have cases where the initial >> setup for a visit has different allocation (depending on whether >> the fields represent a stand-alone type or are embedded as part >> of a larger type), but where the actual field visits are >> identical once a pointer is available. >> >> Up until the previous patch, visit_type_FOO_fields() was only >> used for structs (no variants), so it was covering every field >> for each type where it was emitted. >> >> Meanwhile, the code for visiting unions looks like:
Maybe reword this to: Meanwhile, the previous patch updated the code for visiting unions to look like: >> The resulting diff to the generated code is a bit hard to read, > > Mostly because a few visit_type_T_fields() get generated in a different > place. If I move them back manually for a diff, the patch's effect > becomes clear enough: the switch to visit the variants and the > visit_start_union() guarding it moves from visit_type_T() to > visit_type_T_fields(). That's what the commit message promises. I debated about splitting out a separate patch so that the motion of visit_type_T_fields() is separate from the variant visiting, but it wasn't worth the effort. I'm glad you managed to see through the churn in the generated code. >> -def gen_visit_struct_fields(name, base, members): >> +def gen_visit_struct_fields(name, base, members, variants=None): > > Two callers: > > * gen_visit_union(): the new code here comes from there, except it's now > completely guarded by if variants. Effect: generated code motion. > > * gen_visit_struct(): passes no variants, guard false, thus no change. > > I think the patch becomes slightly clearer if you make the variants > parameter mandatory. It'll probably become mandatory anyway when we > unify gen_visit_struct() and gen_visit_union(). You beat me to it - yes, I realized that after sending the series. We can either squash in the fix here to make variants mandatory (and gen_visit_struct() pass an explicit None, which disappears in the next patch), or squash in a fix to 7/15 to delete the '=None'. Either way, I'm fine if you tackle that, if no other major findings turn up. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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