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[Qemu-devel] [PATCH v10 09/13] qapi: Emit structs used as variants in to
From: |
Eric Blake |
Subject: |
[Qemu-devel] [PATCH v10 09/13] qapi: Emit structs used as variants in topological order |
Date: |
Mon, 15 Feb 2016 17:20:53 -0700 |
Right now, we emit the branches of union types as a boxed pointer,
and it suffices to have a forward declaration of the type. However,
a future patch will swap things to directly use the branch type,
instead of hiding it behind a pointer. For this to work, the
compiler needs the full definition of the type, not just a forward
declaration, prior to the union that is including the branch type.
This patch just adds topological sorting to hoist all types
mentioned in a branch of a union to be fully declared before the
union itself. The sort is always possible, because we do not
allow circular union types that include themselves as a direct
branch (it is, however, still possible to include a branch type
that itself has a pointer to the union, for a type that can
indirectly recursively nest itself - that remains safe, because
that the member of the branch type will remain a pointer, and the
QMP representation of such a type adds another {} for each recurring
layer of the union type).
Signed-off-by: Eric Blake <address@hidden>
---
v10: new patch
---
scripts/qapi-types.py | 23 ++++++++++++++++++++---
1 file changed, 20 insertions(+), 3 deletions(-)
diff --git a/scripts/qapi-types.py b/scripts/qapi-types.py
index 83f230a..2f23432 100644
--- a/scripts/qapi-types.py
+++ b/scripts/qapi-types.py
@@ -2,7 +2,7 @@
# QAPI types generator
#
# Copyright IBM, Corp. 2011
-# Copyright (c) 2013-2015 Red Hat Inc.
+# Copyright (c) 2013-2016 Red Hat Inc.
#
# Authors:
# Anthony Liguori <address@hidden>
@@ -14,6 +14,11 @@
from qapi import *
+# variants must be emitted before their container; track what has already
+# been output
+objects_seen = set()
+
+
def gen_fwd_object_or_array(name):
return mcgen('''
@@ -49,11 +54,23 @@ def gen_struct_fields(members):
def gen_object(name, base, members, variants):
- ret = mcgen('''
+ if name in objects_seen:
+ return ''
+ objects_seen.add(name)
+
+ ret = ''
+ if variants:
+ for v in variants.variants:
+ if isinstance(v.type, QAPISchemaObjectType) and \
+ not v.type.is_implicit():
+ ret += gen_object(v.type.name, v.type.base,
+ v.type.local_members, v.type.variants)
+
+ ret += mcgen('''
struct %(c_name)s {
''',
- c_name=c_name(name))
+ c_name=c_name(name))
if base:
ret += mcgen('''
--
2.5.0
- Re: [Qemu-devel] [PATCH v10 10/13] qapi: Don't box struct branch of alternate, (continued)
[Qemu-devel] [PATCH v10 11/13] qapi: Don't box branches of flat unions, Eric Blake, 2016/02/15
[Qemu-devel] [PATCH v10 13/13] qapi: Change visit_start_implicit_struct to visit_start_alternate, Eric Blake, 2016/02/15
[Qemu-devel] [PATCH v10 09/13] qapi: Emit structs used as variants in topological order,
Eric Blake <=
[Qemu-devel] [PATCH v10 12/13] qapi: Delete unused visit_start_union(), Eric Blake, 2016/02/15