qemu-patch-raspberry4/scripts/qapi-types.py
Eric Blake ac4338f8eb qapi: Allow anonymous base for flat union
Rather than requiring all flat unions to explicitly create
a separate base struct, we can allow the qapi schema to specify
the common members via an inline dictionary. This is similar to
how commands can specify an inline anonymous type for its 'data'.
We already have several struct types that only exist to serve as
a single flat union's base; the next commit will clean them up.
In particular, this patch's change to the BlockdevOptions example
in qapi-code-gen.txt will actually be done in the real QAPI schema.

Now that anonymous bases are legal, we need to rework the
flat-union-bad-base negative test (as previously written, it
forms what is now valid QAPI; tweak it to now provide coverage
of a new error message path), and add a positive test in
qapi-schema-test to use an anonymous base (making the integer
argument optional, for even more coverage).

Note that this patch only allows anonymous bases for flat unions;
simple unions are already enough syntactic sugar that we do not
want to burden them further.  Meanwhile, while it would be easy
to also allow an anonymous base for structs, that would be quite
redundant, as the members can be put right into the struct
instead.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1458254921-17042-15-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-03-18 10:29:26 +01:00

309 lines
8.2 KiB
Python

#
# QAPI types generator
#
# Copyright IBM, Corp. 2011
# Copyright (c) 2013-2016 Red Hat Inc.
#
# Authors:
# Anthony Liguori <aliguori@us.ibm.com>
# Markus Armbruster <armbru@redhat.com>
#
# This work is licensed under the terms of the GNU GPL, version 2.
# See the COPYING file in the top-level directory.
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('''
typedef struct %(c_name)s %(c_name)s;
''',
c_name=c_name(name))
def gen_array(name, element_type):
return mcgen('''
struct %(c_name)s {
%(c_name)s *next;
%(c_type)s value;
};
''',
c_name=c_name(name), c_type=element_type.c_type())
def gen_struct_members(members):
ret = ''
for memb in members:
if memb.optional:
ret += mcgen('''
bool has_%(c_name)s;
''',
c_name=c_name(memb.name))
ret += mcgen('''
%(c_type)s %(c_name)s;
''',
c_type=memb.type.c_type(), c_name=c_name(memb.name))
return ret
def gen_object(name, base, members, variants):
if name in objects_seen:
return ''
objects_seen.add(name)
ret = ''
if variants:
for v in variants.variants:
if isinstance(v.type, QAPISchemaObjectType):
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))
if base:
if not base.is_implicit():
ret += mcgen('''
/* Members inherited from %(c_name)s: */
''',
c_name=base.c_name())
ret += gen_struct_members(base.members)
if not base.is_implicit():
ret += mcgen('''
/* Own members: */
''')
ret += gen_struct_members(members)
if variants:
ret += gen_variants(variants)
# Make sure that all structs have at least one member; this avoids
# potential issues with attempting to malloc space for zero-length
# structs in C, and also incompatibility with C++ (where an empty
# struct is size 1).
if not (base and base.members) and not members and not variants:
ret += mcgen('''
char qapi_dummy_for_empty_struct;
''')
ret += mcgen('''
};
''')
return ret
def gen_upcast(name, base):
# C makes const-correctness ugly. We have to cast away const to let
# this function work for both const and non-const obj.
return mcgen('''
static inline %(base)s *qapi_%(c_name)s_base(const %(c_name)s *obj)
{
return (%(base)s *)obj;
}
''',
c_name=c_name(name), base=base.c_name())
def gen_variants(variants):
ret = mcgen('''
union { /* union tag is @%(c_name)s */
''',
c_name=c_name(variants.tag_member.name))
for var in variants.variants:
ret += mcgen('''
%(c_type)s %(c_name)s;
''',
c_type=var.type.c_unboxed_type(),
c_name=c_name(var.name))
ret += mcgen('''
} u;
''')
return ret
def gen_type_cleanup_decl(name):
ret = mcgen('''
void qapi_free_%(c_name)s(%(c_name)s *obj);
''',
c_name=c_name(name))
return ret
def gen_type_cleanup(name):
ret = mcgen('''
void qapi_free_%(c_name)s(%(c_name)s *obj)
{
QapiDeallocVisitor *qdv;
Visitor *v;
if (!obj) {
return;
}
qdv = qapi_dealloc_visitor_new();
v = qapi_dealloc_get_visitor(qdv);
visit_type_%(c_name)s(v, NULL, &obj, NULL);
qapi_dealloc_visitor_cleanup(qdv);
}
''',
c_name=c_name(name))
return ret
class QAPISchemaGenTypeVisitor(QAPISchemaVisitor):
def __init__(self):
self.decl = None
self.defn = None
self._fwdecl = None
self._btin = None
def visit_begin(self, schema):
# gen_object() is recursive, ensure it doesn't visit the empty type
objects_seen.add(schema.the_empty_object_type.name)
self.decl = ''
self.defn = ''
self._fwdecl = ''
self._btin = guardstart('QAPI_TYPES_BUILTIN')
def visit_end(self):
self.decl = self._fwdecl + self.decl
self._fwdecl = None
# To avoid header dependency hell, we always generate
# declarations for built-in types in our header files and
# simply guard them. See also do_builtins (command line
# option -b).
self._btin += guardend('QAPI_TYPES_BUILTIN')
self.decl = self._btin + self.decl
self._btin = None
def _gen_type_cleanup(self, name):
self.decl += gen_type_cleanup_decl(name)
self.defn += gen_type_cleanup(name)
def visit_enum_type(self, name, info, values, prefix):
# Special case for our lone builtin enum type
# TODO use something cleaner than existence of info
if not info:
self._btin += gen_enum(name, values, prefix)
if do_builtins:
self.defn += gen_enum_lookup(name, values, prefix)
else:
self._fwdecl += gen_enum(name, values, prefix)
self.defn += gen_enum_lookup(name, values, prefix)
def visit_array_type(self, name, info, element_type):
if isinstance(element_type, QAPISchemaBuiltinType):
self._btin += gen_fwd_object_or_array(name)
self._btin += gen_array(name, element_type)
self._btin += gen_type_cleanup_decl(name)
if do_builtins:
self.defn += gen_type_cleanup(name)
else:
self._fwdecl += gen_fwd_object_or_array(name)
self.decl += gen_array(name, element_type)
self._gen_type_cleanup(name)
def visit_object_type(self, name, info, base, members, variants):
# Nothing to do for the special empty builtin
if name == 'q_empty':
return
self._fwdecl += gen_fwd_object_or_array(name)
self.decl += gen_object(name, base, members, variants)
if base and not base.is_implicit():
self.decl += gen_upcast(name, base)
# TODO Worth changing the visitor signature, so we could
# directly use rather than repeat type.is_implicit()?
if not name.startswith('q_'):
# implicit types won't be directly allocated/freed
self._gen_type_cleanup(name)
def visit_alternate_type(self, name, info, variants):
self._fwdecl += gen_fwd_object_or_array(name)
self.decl += gen_object(name, None, [variants.tag_member], variants)
self._gen_type_cleanup(name)
# If you link code generated from multiple schemata, you want only one
# instance of the code for built-in types. Generate it only when
# do_builtins, enabled by command line option -b. See also
# QAPISchemaGenTypeVisitor.visit_end().
do_builtins = False
(input_file, output_dir, do_c, do_h, prefix, opts) = \
parse_command_line("b", ["builtins"])
for o, a in opts:
if o in ("-b", "--builtins"):
do_builtins = True
c_comment = '''
/*
* deallocation functions for schema-defined QAPI types
*
* Copyright IBM, Corp. 2011
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
* Michael Roth <mdroth@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
'''
h_comment = '''
/*
* schema-defined QAPI types
*
* Copyright IBM, Corp. 2011
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
'''
(fdef, fdecl) = open_output(output_dir, do_c, do_h, prefix,
'qapi-types.c', 'qapi-types.h',
c_comment, h_comment)
fdef.write(mcgen('''
#include "qemu/osdep.h"
#include "qapi/dealloc-visitor.h"
#include "%(prefix)sqapi-types.h"
#include "%(prefix)sqapi-visit.h"
''',
prefix=prefix))
# To avoid circular headers, use only typedefs.h here, not qobject.h
fdecl.write(mcgen('''
#include "qemu/typedefs.h"
'''))
schema = QAPISchema(input_file)
gen = QAPISchemaGenTypeVisitor()
schema.visit(gen)
fdef.write(gen.defn)
fdecl.write(gen.decl)
close_output(fdef, fdecl)