| Message ID | 1455582057-27565-6-git-send-email-eblake@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Eric Blake <eblake@redhat.com> writes: > From: Markus Armbruster <armbru@redhat.com> > > For a simple union SU, gen_visit_union() generates a visit of its > single tag member, like this: > > visit_type_SUKind(v, "type", &(*obj)->type, &err); > > For a flat union FU with base B, it generates a visit of its base > fields: > > visit_type_B_fields(v, (B **)obj, &err); > > Instead, we can simply visit the common members using the same fields > visit function we use for structs, generated with > gen_visit_struct_fields(). This function visits the base if any, then > the local members. > > For a simple union SU, visit_type_SU_fields() contains exactly the old > tag member visit, because there is no base, and the tag member is the > only member. For instance, the code generated for qapi-schema.json's > KeyValue changes like this: > > +static void visit_type_KeyValue_fields(Visitor *v, KeyValue **obj, Error **errp) > +{ > + Error *err = NULL; > + > + visit_type_KeyValueKind(v, "type", &(*obj)->type, &err); > + error_propagate(errp, err); > +} > + > void visit_type_KeyValue(Visitor *v, const char *name, KeyValue **obj, Error **errp) > { > Error *err = NULL; > @@ -4863,7 +4911,7 @@ void visit_type_KeyValue(Visitor *v, con > if (!*obj) { > goto out_obj; > } > - visit_type_KeyValueKind(v, "type", &(*obj)->type, &err); > + visit_type_KeyValue_fields(v, obj, &err); > if (err) { > goto out_obj; > } > > For a flat union FU, visit_type_FU_fields() contains exactly the old > base fields visit, because there is a base, but no members. For > instance, the code generated for qapi-schema.json's CpuInfo changes > like this: > > static void visit_type_CpuInfoBase_fields(Visitor *v, CpuInfoBase **obj, Error **errp); > > +static void visit_type_CpuInfo_fields(Visitor *v, CpuInfo **obj, Error **errp) > +{ > + Error *err = NULL; > + > + visit_type_CpuInfoBase_fields(v, (CpuInfoBase **)obj, &err); > + error_propagate(errp, err); > +} > + > static void visit_type_CpuInfoX86_fields(Visitor *v, CpuInfoX86 **obj, Error **errp) > ... > @@ -3485,7 +3509,7 @@ void visit_type_CpuInfo(Visitor *v, cons > if (!*obj) { > goto out_obj; > } > - visit_type_CpuInfoBase_fields(v, (CpuInfoBase **)obj, &err); > + visit_type_CpuInfo_fields(v, obj, &err); > if (err) { > goto out_obj; > } > > As you see, the generated code grows a bit, but in practice, it's lost > in the noise: qapi-schema.json's qapi-visit.c gains roughly 1%. > > This simplification became possible with commit 441cbac "qapi-visit: > Convert to QAPISchemaVisitor, fixing bugs". It's a step towards > unifying gen_struct() and gen_union(). > > Signed-off-by: Markus Armbruster <armbru@redhat.com> > Message-Id: <1453902888-20457-2-git-send-email-armbru@redhat.com> > [rebase to avoid pointless gotos in new code] Also: examples in commit message replaced by better ones :) > Signed-off-by: Eric Blake <eblake@redhat.com>
On 02/16/2016 09:31 AM, Markus Armbruster wrote: > Eric Blake <eblake@redhat.com> writes: > >> From: Markus Armbruster <armbru@redhat.com> >> >> For a simple union SU, gen_visit_union() generates a visit of its >> single tag member, like this: >> >> visit_type_SUKind(v, "type", &(*obj)->type, &err); >> >> For a flat union FU with base B, it generates a visit of its base >> fields: >> >> visit_type_B_fields(v, (B **)obj, &err); >> >> Instead, we can simply visit the common members using the same fields >> visit function we use for structs, generated with >> gen_visit_struct_fields(). This function visits the base if any, then >> the local members. >> >> For a simple union SU, visit_type_SU_fields() contains exactly the old >> tag member visit, because there is no base, and the tag member is the >> only member. For instance, the code generated for qapi-schema.json's >> KeyValue changes like this: >> >> +static void visit_type_KeyValue_fields(Visitor *v, KeyValue **obj, Error **errp) >> +{ >> + Error *err = NULL; >> + >> + visit_type_KeyValueKind(v, "type", &(*obj)->type, &err); >> + error_propagate(errp, err); >> +} >> + This is one of the places that is several lines longer if we always emit the goto and label. If we drop 3 and 4, then the commit message needs a rebase. >> void visit_type_KeyValue(Visitor *v, const char *name, KeyValue **obj, Error **errp) >> { >> Error *err = NULL; >> @@ -4863,7 +4911,7 @@ void visit_type_KeyValue(Visitor *v, con >> if (!*obj) { >> goto out_obj; >> } >> - visit_type_KeyValueKind(v, "type", &(*obj)->type, &err); >> + visit_type_KeyValue_fields(v, obj, &err); >> if (err) { >> goto out_obj; >> } >> >> For a flat union FU, visit_type_FU_fields() contains exactly the old >> base fields visit, because there is a base, but no members. For >> instance, the code generated for qapi-schema.json's CpuInfo changes >> like this: >> >> static void visit_type_CpuInfoBase_fields(Visitor *v, CpuInfoBase **obj, Error **errp); >> >> +static void visit_type_CpuInfo_fields(Visitor *v, CpuInfo **obj, Error **errp) >> +{ >> + Error *err = NULL; >> + >> + visit_type_CpuInfoBase_fields(v, (CpuInfoBase **)obj, &err); >> + error_propagate(errp, err); >> +} And another beneficiary of the omitted goto that gets longer. >> + >> static void visit_type_CpuInfoX86_fields(Visitor *v, CpuInfoX86 **obj, Error **errp) >> ... >> @@ -3485,7 +3509,7 @@ void visit_type_CpuInfo(Visitor *v, cons >> if (!*obj) { >> goto out_obj; >> } >> - visit_type_CpuInfoBase_fields(v, (CpuInfoBase **)obj, &err); >> + visit_type_CpuInfo_fields(v, obj, &err); >> if (err) { >> goto out_obj; >> } >> >> As you see, the generated code grows a bit, but in practice, it's lost >> in the noise: qapi-schema.json's qapi-visit.c gains roughly 1%. >> >> This simplification became possible with commit 441cbac "qapi-visit: >> Convert to QAPISchemaVisitor, fixing bugs". It's a step towards >> unifying gen_struct() and gen_union(). >> >> Signed-off-by: Markus Armbruster <armbru@redhat.com> >> Message-Id: <1453902888-20457-2-git-send-email-armbru@redhat.com> >> [rebase to avoid pointless gotos in new code] > > Also: examples in commit message replaced by better ones :) I picked the shortest names possible, to minimize the length of the commit message, and favoring qapi-schema.json over the testsuite. You noticed :) > >> Signed-off-by: Eric Blake <eblake@redhat.com> >
diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py index 0be396b..0530f2b 100644 --- a/scripts/qapi-visit.py +++ b/scripts/qapi-visit.py @@ -240,11 +240,8 @@ out: return ret -def gen_visit_union(name, base, variants): - ret = '' - - if base: - ret += gen_visit_fields_decl(base) +def gen_visit_union(name, base, members, variants): + ret = gen_visit_struct_fields(name, base, members) for var in variants.variants: # Ugly special case for simple union TODO get rid of it @@ -264,21 +261,9 @@ void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error if (!*obj) { goto out_obj; } + visit_type_%(c_name)s_fields(v, obj, &err); ''', c_name=c_name(name)) - - if base: - ret += mcgen(''' - visit_type_%(c_name)s_fields(v, (%(c_name)s **)obj, &err); -''', - c_name=base.c_name()) - else: - ret += mcgen(''' - visit_type_%(c_type)s(v, "%(name)s", &(*obj)->%(c_name)s, &err); -''', - c_type=variants.tag_member.type.c_name(), - c_name=c_name(variants.tag_member.name), - name=variants.tag_member.name) ret += gen_err_check(label='out_obj') ret += mcgen(''' if (!visit_start_union(v, !!(*obj)->u.data, &err) || err) { @@ -378,11 +363,7 @@ class QAPISchemaGenVisitVisitor(QAPISchemaVisitor): def visit_object_type(self, name, info, base, members, variants): self.decl += gen_visit_decl(name) if variants: - if members: - # Members other than variants.tag_member not implemented - assert len(members) == 1 - assert members[0] == variants.tag_member - self.defn += gen_visit_union(name, base, variants) + self.defn += gen_visit_union(name, base, members, variants) else: self.defn += gen_visit_struct(name, base, members)