Merge remote-tracking branch 'remotes/ericb/tags/pull-qapi-2018-03-01-v4' into staging

qapi patches for 2018-03-01

- Markus Armbruster: Modularize generated QAPI code

# gpg: Signature made Fri 02 Mar 2018 19:50:16 GMT
# gpg:                using RSA key A7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>"
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>"
# gpg:                 aka "[jpeg image of size 6874]"
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-qapi-2018-03-01-v4: (30 commits)
  qapi: Don't create useless directory qapi-generated
  Fix up dangling references to qmp-commands.* in comment and doc
  qapi: Move qapi-schema.json to qapi/, rename generated files
  docs: Correct outdated information on QAPI
  docs/devel/writing-qmp-commands: Update for modular QAPI
  qapi: Empty out qapi-schema.json
  Include less of the generated modular QAPI headers
  qapi: Generate separate .h, .c for each module
  watchdog: Consolidate QAPI into single file
  qapi/common: Fix guardname() for funny filenames
  qapi/types qapi/visit: Generate built-in stuff into separate files
  qapi: Make code-generating visitors use QAPIGen more
  qapi: Rename generated qmp-marshal.c to qmp-commands.c
  qapi: Record 'include' directives in intermediate representation
  qapi: Generate in source order
  qapi: Record 'include' directives in parse tree
  qapi: Concentrate QAPISchemaParser.exprs updates in .__init__()
  qapi: Lift error reporting from QAPISchema.__init__() to callers
  qapi/common: Eliminate QAPISchema.exprs
  qapi: Improve include file name reporting in error messages
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

9 files changed, 591 insertions, 694 deletions

diff --git a/scripts/qapi-gen.py b/scripts/qapi-gen.py
new file mode 100755
index 0000000..3d98ca2
--- /dev/null
+++ b/scripts/qapi-gen.py
@@ -0,0 +1,57 @@
+#!/usr/bin/env python
+# QAPI generator
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or later.
+# See the COPYING file in the top-level directory.
+
+from __future__ import print_function
+import argparse
+import re
+import sys
+from qapi.common import QAPIError, QAPISchema
+from qapi.types import gen_types
+from qapi.visit import gen_visit
+from qapi.commands import gen_commands
+from qapi.events import gen_events
+from qapi.introspect import gen_introspect
+from qapi.doc import gen_doc
+
+
+def main(argv):
+    parser = argparse.ArgumentParser(
+        description='Generate code from a QAPI schema')
+    parser.add_argument('-b', '--builtins', action='store_true',
+                        help="generate code for built-in types")
+    parser.add_argument('-o', '--output-dir', action='store', default='',
+                        help="write output to directory OUTPUT_DIR")
+    parser.add_argument('-p', '--prefix', action='store', default='',
+                        help="prefix for symbols")
+    parser.add_argument('-u', '--unmask-non-abi-names', action='store_true',
+                        dest='unmask',
+                        help="expose non-ABI names in introspection")
+    parser.add_argument('schema', action='store')
+    args = parser.parse_args()
+
+    match = re.match(r'([A-Za-z_.-][A-Za-z0-9_.-]*)?', args.prefix)
+    if match.end() != len(args.prefix):
+        print("%s: 'funny character '%s' in argument of --prefix"
+              % (sys.argv[0], args.prefix[match.end()]),
+              file=sys.stderr)
+        sys.exit(1)
+
+    try:
+        schema = QAPISchema(args.schema)
+    except QAPIError as err:
+        print(err, file=sys.stderr)
+        exit(1)
+
+    gen_types(schema, args.output_dir, args.prefix, args.builtins)
+    gen_visit(schema, args.output_dir, args.prefix, args.builtins)
+    gen_commands(schema, args.output_dir, args.prefix)
+    gen_events(schema, args.output_dir, args.prefix)
+    gen_introspect(schema, args.output_dir, args.prefix, args.unmask)
+    gen_doc(schema, args.output_dir, args.prefix)
+
+
+if __name__ == '__main__':
+    main(sys.argv)
diff --git a/scripts/qapi/__init__.py b/scripts/qapi/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/scripts/qapi/__init__.py
diff --git a/scripts/qapi-commands.py b/scripts/qapi/commands.py
index f89d748..21a7e0d 100644
--- a/scripts/qapi-commands.py
+++ b/scripts/qapi/commands.py
@@ -1,18 +1,19 @@
-#
-# QAPI command marshaller generator
-#
-# Copyright IBM, Corp. 2011
-# Copyright (C) 2014-2016 Red Hat, Inc.
-#
-# Authors:
-#  Anthony Liguori <aliguori@us.ibm.com>
-#  Michael Roth    <mdroth@linux.vnet.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 *
+"""
+QAPI command marshaller generator
+
+Copyright IBM, Corp. 2011
+Copyright (C) 2014-2018 Red Hat, Inc.
+
+Authors:
+ Anthony Liguori <aliguori@us.ibm.com>
+ Michael Roth <mdroth@linux.vnet.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.common import *
 
 
 def gen_command_decl(name, arg_type, boxed, ret_type):
@@ -206,7 +207,7 @@ def gen_register_command(name, success_response):
     return ret
 
 
-def gen_registry(registry):
+def gen_registry(registry, prefix):
     ret = mcgen('''
 
 void %(c_prefix)sqmp_init_marshal(QmpCommandList *cmds)
@@ -222,74 +223,21 @@ void %(c_prefix)sqmp_init_marshal(QmpCommandList *cmds)
     return ret
 
 
-class QAPISchemaGenCommandVisitor(QAPISchemaVisitor):
-    def __init__(self):
-        self.decl = None
-        self.defn = None
-        self._regy = None
-        self._visited_ret_types = None
+class QAPISchemaGenCommandVisitor(QAPISchemaModularCVisitor):
 
-    def visit_begin(self, schema):
-        self.decl = ''
-        self.defn = ''
+    def __init__(self, prefix):
+        QAPISchemaModularCVisitor.__init__(
+            self, prefix, 'qapi-commands',
+            ' * Schema-defined QAPI/QMP commands', __doc__)
         self._regy = ''
-        self._visited_ret_types = set()
-
-    def visit_end(self):
-        self.defn += gen_registry(self._regy)
-        self._regy = None
-        self._visited_ret_types = None
-
-    def visit_command(self, name, info, arg_type, ret_type,
-                      gen, success_response, boxed):
-        if not gen:
-            return
-        self.decl += gen_command_decl(name, arg_type, boxed, ret_type)
-        if ret_type and ret_type not in self._visited_ret_types:
-            self._visited_ret_types.add(ret_type)
-            self.defn += gen_marshal_output(ret_type)
-        self.decl += gen_marshal_decl(name)
-        self.defn += gen_marshal(name, arg_type, boxed, ret_type)
-        self._regy += gen_register_command(name, success_response)
-
-
-(input_file, output_dir, do_c, do_h, prefix, opts) = parse_command_line()
-
-c_comment = '''
-/*
- * schema-defined QMP->QAPI command dispatch
- *
- * 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.
- *
- */
-'''
-h_comment = '''
-/*
- * schema-defined QAPI function prototypes
- *
- * 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,
-                            'qmp-marshal.c', 'qmp-commands.h',
-                            c_comment, h_comment)
-
-fdef.write(mcgen('''
-
+        self._visited_ret_types = {}
+
+    def _begin_module(self, name):
+        self._visited_ret_types[self._genc] = set()
+        commands = self._module_basename('qapi-commands', name)
+        types = self._module_basename('qapi-types', name)
+        visit = self._module_basename('qapi-visit', name)
+        self._genc.add(mcgen('''
 #include "qemu/osdep.h"
 #include "qemu-common.h"
 #include "qemu/module.h"
@@ -299,25 +247,40 @@ fdef.write(mcgen('''
 #include "qapi/qobject-input-visitor.h"
 #include "qapi/dealloc-visitor.h"
 #include "qapi/error.h"
-#include "%(prefix)sqapi-types.h"
-#include "%(prefix)sqapi-visit.h"
-#include "%(prefix)sqmp-commands.h"
+#include "%(visit)s.h"
+#include "%(commands)s.h"
 
 ''',
-                 prefix=prefix))
-
-fdecl.write(mcgen('''
-#include "%(prefix)sqapi-types.h"
+                             commands=commands, visit=visit))
+        self._genh.add(mcgen('''
+#include "%(types)s.h"
 #include "qapi/qmp/dispatch.h"
 
+''',
+                             types=types))
+
+    def visit_end(self):
+        (genc, genh) = self._module[self._main_module]
+        genh.add(mcgen('''
 void %(c_prefix)sqmp_init_marshal(QmpCommandList *cmds);
 ''',
-                  prefix=prefix, c_prefix=c_name(prefix, protect=False)))
+                       c_prefix=c_name(self._prefix, protect=False)))
+        genc.add(gen_registry(self._regy, self._prefix))
+
+    def visit_command(self, name, info, arg_type, ret_type,
+                      gen, success_response, boxed):
+        if not gen:
+            return
+        self._genh.add(gen_command_decl(name, arg_type, boxed, ret_type))
+        if ret_type and ret_type not in self._visited_ret_types[self._genc]:
+            self._visited_ret_types[self._genc].add(ret_type)
+            self._genc.add(gen_marshal_output(ret_type))
+        self._genh.add(gen_marshal_decl(name))
+        self._genc.add(gen_marshal(name, arg_type, boxed, ret_type))
+        self._regy += gen_register_command(name, success_response)
 
-schema = QAPISchema(input_file)
-gen = QAPISchemaGenCommandVisitor()
-schema.visit(gen)
-fdef.write(gen.defn)
-fdecl.write(gen.decl)
 
-close_output(fdef, fdecl)
+def gen_commands(schema, output_dir, prefix):
+    vis = QAPISchemaGenCommandVisitor(prefix)
+    schema.visit(vis)
+    vis.write(output_dir)
diff --git a/scripts/qapi.py b/scripts/qapi/common.py
index 58f995b..97e9060 100644
--- a/scripts/qapi.py
+++ b/scripts/qapi/common.py
@@ -2,7 +2,7 @@
 # QAPI helper library
 #
 # Copyright IBM, Corp. 2011
-# Copyright (c) 2013-2016 Red Hat Inc.
+# Copyright (c) 2013-2018 Red Hat Inc.
 #
 # Authors:
 #  Anthony Liguori <aliguori@us.ibm.com>
@@ -13,19 +13,13 @@
 
 from __future__ import print_function
 import errno
-import getopt
 import os
 import re
 import string
-import sys
 try:
     from collections import OrderedDict
 except:
     from ordereddict import OrderedDict
-try:
-    from StringIO import StringIO
-except ImportError:
-    from io import StringIO
 
 builtin_types = {
     'null':     'QTYPE_QNULL',
@@ -264,9 +258,8 @@ class QAPIDoc(object):
 class QAPISchemaParser(object):
 
     def __init__(self, fp, previously_included=[], incl_info=None):
-        abs_fname = os.path.abspath(fp.name)
         self.fname = fp.name
-        previously_included.append(abs_fname)
+        previously_included.append(os.path.abspath(fp.name))
         self.incl_info = incl_info
         self.src = fp.read()
         if self.src == '' or self.src[-1] != '\n':
@@ -297,8 +290,15 @@ class QAPISchemaParser(object):
                 if not isinstance(include, str):
                     raise QAPISemError(info,
                                        "Value of 'include' must be a string")
-                self._include(include, info, os.path.dirname(abs_fname),
-                              previously_included)
+                incl_fname = os.path.join(os.path.dirname(self.fname),
+                                          include)
+                self.exprs.append({'expr': {'include': incl_fname},
+                                   'info': info})
+                exprs_include = self._include(include, info, incl_fname,
+                                              previously_included)
+                if exprs_include:
+                    self.exprs.extend(exprs_include.exprs)
+                    self.docs.extend(exprs_include.docs)
             elif "pragma" in expr:
                 self.reject_expr_doc(cur_doc)
                 if len(expr) != 1:
@@ -329,8 +329,8 @@ class QAPISchemaParser(object):
                 "Documentation for '%s' is not followed by the definition"
                 % doc.symbol)
 
-    def _include(self, include, info, base_dir, previously_included):
-        incl_abs_fname = os.path.join(base_dir, include)
+    def _include(self, include, info, incl_fname, previously_included):
+        incl_abs_fname = os.path.abspath(incl_fname)
         # catch inclusion cycle
         inf = info
         while inf:
@@ -340,14 +340,13 @@ class QAPISchemaParser(object):
 
         # skip multiple include of the same file
         if incl_abs_fname in previously_included:
-            return
+            return None
+
         try:
-            fobj = open(incl_abs_fname, 'r')
+            fobj = open(incl_fname, 'r')
         except IOError as e:
-            raise QAPISemError(info, '%s: %s' % (e.strerror, include))
-        exprs_include = QAPISchemaParser(fobj, previously_included, info)
-        self.exprs.extend(exprs_include.exprs)
-        self.docs.extend(exprs_include.docs)
+            raise QAPISemError(info, '%s: %s' % (e.strerror, incl_fname))
+        return QAPISchemaParser(fobj, previously_included, info)
 
     def _pragma(self, name, value, info):
         global doc_required, returns_whitelist, name_case_whitelist
@@ -896,6 +895,9 @@ def check_exprs(exprs):
         info = expr_elem['info']
         doc = expr_elem.get('doc')
 
+        if 'include' in expr:
+            continue
+
         if not doc and doc_required:
             raise QAPISemError(info,
                                "Expression missing documentation comment")
@@ -935,6 +937,9 @@ def check_exprs(exprs):
     # Try again for hidden UnionKind enum
     for expr_elem in exprs:
         expr = expr_elem['expr']
+
+        if 'include' in expr:
+            continue
         if 'union' in expr and not discriminator_find_enum_define(expr):
             name = '%sKind' % expr['union']
         elif 'alternate' in expr:
@@ -950,6 +955,8 @@ def check_exprs(exprs):
         info = expr_elem['info']
         doc = expr_elem.get('doc')
 
+        if 'include' in expr:
+            continue
         if 'enum' in expr:
             check_enum(expr, info)
         elif 'union' in expr:
@@ -977,8 +984,9 @@ def check_exprs(exprs):
 
 class QAPISchemaEntity(object):
     def __init__(self, name, info, doc):
-        assert isinstance(name, str)
+        assert name is None or isinstance(name, str)
         self.name = name
+        self.module = None
         # For explicitly defined entities, info points to the (explicit)
         # definition.  For builtins (and their arrays), info is None.
         # For implicitly defined entities, info points to a place that
@@ -1007,10 +1015,16 @@ class QAPISchemaVisitor(object):
     def visit_end(self):
         pass
 
+    def visit_module(self, fname):
+        pass
+
     def visit_needed(self, entity):
         # Default to visiting everything
         return True
 
+    def visit_include(self, fname, info):
+        pass
+
     def visit_builtin_type(self, name, info, json_type):
         pass
 
@@ -1037,6 +1051,16 @@ class QAPISchemaVisitor(object):
         pass
 
 
+class QAPISchemaInclude(QAPISchemaEntity):
+
+    def __init__(self, fname, info):
+        QAPISchemaEntity.__init__(self, None, info, None)
+        self.fname = fname
+
+    def visit(self, visitor):
+        visitor.visit_include(self.fname, self.info)
+
+
 class QAPISchemaType(QAPISchemaEntity):
     # Return the C type for common use.
     # For the types we commonly box, this is a pointer type.
@@ -1464,25 +1488,28 @@ class QAPISchemaEvent(QAPISchemaEntity):
 
 class QAPISchema(object):
     def __init__(self, fname):
-        try:
-            parser = QAPISchemaParser(open(fname, 'r'))
-            self.exprs = check_exprs(parser.exprs)
-            self.docs = parser.docs
-            self._entity_dict = {}
-            self._predefining = True
-            self._def_predefineds()
-            self._predefining = False
-            self._def_exprs()
-            self.check()
-        except QAPIError as err:
-            print(err, file=sys.stderr)
-            exit(1)
+        self._fname = fname
+        parser = QAPISchemaParser(open(fname, 'r'))
+        exprs = check_exprs(parser.exprs)
+        self.docs = parser.docs
+        self._entity_list = []
+        self._entity_dict = {}
+        self._predefining = True
+        self._def_predefineds()
+        self._predefining = False
+        self._def_exprs(exprs)
+        self.check()
 
     def _def_entity(self, ent):
         # Only the predefined types are allowed to not have info
         assert ent.info or self._predefining
-        assert ent.name not in self._entity_dict
-        self._entity_dict[ent.name] = ent
+        assert ent.name is None or ent.name not in self._entity_dict
+        self._entity_list.append(ent)
+        if ent.name is not None:
+            self._entity_dict[ent.name] = ent
+        if ent.info:
+            ent.module = os.path.relpath(ent.info['file'],
+                                         os.path.dirname(self._fname))
 
     def lookup_entity(self, name, typ=None):
         ent = self._entity_dict.get(name)
@@ -1493,13 +1520,21 @@ class QAPISchema(object):
     def lookup_type(self, name):
         return self.lookup_entity(name, QAPISchemaType)
 
+    def _def_include(self, expr, info, doc):
+        include = expr['include']
+        assert doc is None
+        main_info = info
+        while main_info['parent']:
+            main_info = main_info['parent']
+        fname = os.path.relpath(include, os.path.dirname(main_info['file']))
+        self._def_entity(QAPISchemaInclude(fname, info))
+
     def _def_builtin_type(self, name, json_type, c_type):
         self._def_entity(QAPISchemaBuiltinType(name, json_type, c_type))
-        # TODO As long as we have QAPI_TYPES_BUILTIN to share multiple
-        # qapi-types.h from a single .c, all arrays of builtins must be
-        # declared in the first file whether or not they are used.  Nicer
-        # would be to use lazy instantiation, while figuring out how to
-        # avoid compilation issues with multiple qapi-types.h.
+        # Instantiating only the arrays that are actually used would
+        # be nice, but we can't as long as their generated code
+        # (qapi-builtin-types.[ch]) may be shared by some other
+        # schema.
         self._make_array_type(name, None)
 
     def _def_predefineds(self):
@@ -1657,8 +1692,8 @@ class QAPISchema(object):
                 name, info, doc, 'arg', self._make_members(data, info))
         self._def_entity(QAPISchemaEvent(name, info, doc, data, boxed))
 
-    def _def_exprs(self):
-        for expr_elem in self.exprs:
+    def _def_exprs(self, exprs):
+        for expr_elem in exprs:
             expr = expr_elem['expr']
             info = expr_elem['info']
             doc = expr_elem.get('doc')
@@ -1674,17 +1709,23 @@ class QAPISchema(object):
                 self._def_command(expr, info, doc)
             elif 'event' in expr:
                 self._def_event(expr, info, doc)
+            elif 'include' in expr:
+                self._def_include(expr, info, doc)
             else:
                 assert False
 
     def check(self):
-        for (name, ent) in sorted(self._entity_dict.items()):
+        for ent in self._entity_list:
             ent.check(self)
 
     def visit(self, visitor):
         visitor.visit_begin(self)
-        for (name, entity) in sorted(self._entity_dict.items()):
+        module = None
+        for entity in self._entity_list:
             if visitor.visit_needed(entity):
+                if entity.module != module:
+                    module = entity.module
+                    visitor.visit_module(module)
                 entity.visit(visitor)
         visitor.visit_end()
 
@@ -1826,12 +1867,11 @@ def mcgen(code, **kwds):
 
 
 def guardname(filename):
-    return c_name(filename, protect=False).upper()
+    return re.sub(r'[^A-Za-z0-9_]', '_', filename).upper()
 
 
 def guardstart(name):
     return mcgen('''
-
 #ifndef %(name)s
 #define %(name)s
 
@@ -1843,7 +1883,6 @@ def guardend(name):
     return mcgen('''
 
 #endif /* %(name)s */
-
 ''',
                  name=guardname(name))
 
@@ -1930,104 +1969,161 @@ def build_params(arg_type, boxed, extra):
 
 
 #
-# Common command line parsing
+# Accumulate and write output
 #
 
+class QAPIGen(object):
+
+    def __init__(self):
+        self._preamble = ''
+        self._body = ''
+
+    def preamble_add(self, text):
+        self._preamble += text
+
+    def add(self, text):
+        self._body += text
+
+    def _top(self, fname):
+        return ''
+
+    def _bottom(self, fname):
+        return ''
+
+    def write(self, output_dir, fname):
+        pathname = os.path.join(output_dir, fname)
+        dir = os.path.dirname(pathname)
+        if dir:
+            try:
+                os.makedirs(dir)
+            except os.error as e:
+                if e.errno != errno.EEXIST:
+                    raise
+        fd = os.open(pathname, os.O_RDWR | os.O_CREAT, 0o666)
+        f = os.fdopen(fd, 'r+')
+        text = (self._top(fname) + self._preamble + self._body
+                + self._bottom(fname))
+        oldtext = f.read(len(text) + 1)
+        if text != oldtext:
+            f.seek(0)
+            f.truncate(0)
+            f.write(text)
+        f.close()
+
+
+class QAPIGenC(QAPIGen):
+
+    def __init__(self, blurb, pydoc):
+        QAPIGen.__init__(self)
+        self._blurb = blurb
+        self._copyright = '\n * '.join(re.findall(r'^Copyright .*', pydoc,
+                                                  re.MULTILINE))
+
+    def _top(self, fname):
+        return mcgen('''
+/* AUTOMATICALLY GENERATED, DO NOT MODIFY */
 
-def parse_command_line(extra_options='', extra_long_options=[]):
-
-    try:
-        opts, args = getopt.gnu_getopt(sys.argv[1:],
-                                       'chp:o:' + extra_options,
-                                       ['source', 'header', 'prefix=',
-                                        'output-dir='] + extra_long_options)
-    except getopt.GetoptError as err:
-        print("%s: %s" % (sys.argv[0], str(err)), file=sys.stderr)
-        sys.exit(1)
-
-    output_dir = ''
-    prefix = ''
-    do_c = False
-    do_h = False
-    extra_opts = []
-
-    for oa in opts:
-        o, a = oa
-        if o in ('-p', '--prefix'):
-            match = re.match(r'([A-Za-z_.-][A-Za-z0-9_.-]*)?', a)
-            if match.end() != len(a):
-                print("%s: 'funny character '%s' in argument of --prefix" \
-                      % (sys.argv[0], a[match.end()]), file=sys.stderr)
-                sys.exit(1)
-            prefix = a
-        elif o in ('-o', '--output-dir'):
-            output_dir = a + '/'
-        elif o in ('-c', '--source'):
-            do_c = True
-        elif o in ('-h', '--header'):
-            do_h = True
-        else:
-            extra_opts.append(oa)
+/*
+%(blurb)s
+ *
+ * %(copyright)s
+ *
+ * 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.
+ */
 
-    if not do_c and not do_h:
-        do_c = True
-        do_h = True
+''',
+                     blurb=self._blurb, copyright=self._copyright)
 
-    if len(args) != 1:
-        print("%s: need exactly one argument" % sys.argv[0], file=sys.stderr)
-        sys.exit(1)
-    fname = args[0]
+    def _bottom(self, fname):
+        return mcgen('''
+/* Dummy declaration to prevent empty .o file */
+char dummy_%(name)s;
+''',
+                     name=c_name(fname))
 
-    return (fname, output_dir, do_c, do_h, prefix, extra_opts)
 
-#
-# Generate output files with boilerplate
-#
+class QAPIGenH(QAPIGenC):
 
+    def _top(self, fname):
+        return QAPIGenC._top(self, fname) + guardstart(fname)
 
-def open_output(output_dir, do_c, do_h, prefix, c_file, h_file,
-                c_comment, h_comment):
-    guard = guardname(prefix + h_file)
-    c_file = output_dir + prefix + c_file
-    h_file = output_dir + prefix + h_file
+    def _bottom(self, fname):
+        return guardend(fname)
 
-    if output_dir:
-        try:
-            os.makedirs(output_dir)
-        except os.error as e:
-            if e.errno != errno.EEXIST:
-                raise
-
-    def maybe_open(really, name, opt):
-        if really:
-            return open(name, opt)
-        else:
-            return StringIO()
 
-    fdef = maybe_open(do_c, c_file, 'w')
-    fdecl = maybe_open(do_h, h_file, 'w')
+class QAPIGenDoc(QAPIGen):
 
-    fdef.write(mcgen('''
-/* AUTOMATICALLY GENERATED, DO NOT MODIFY */
-%(comment)s
-''',
-                     comment=c_comment))
+    def _top(self, fname):
+        return (QAPIGen._top(self, fname)
+                + '@c AUTOMATICALLY GENERATED, DO NOT MODIFY\n\n')
 
-    fdecl.write(mcgen('''
-/* AUTOMATICALLY GENERATED, DO NOT MODIFY */
-%(comment)s
-#ifndef %(guard)s
-#define %(guard)s
 
-''',
-                      comment=h_comment, guard=guard))
+class QAPISchemaMonolithicCVisitor(QAPISchemaVisitor):
+
+    def __init__(self, prefix, what, blurb, pydoc):
+        self._prefix = prefix
+        self._what = what
+        self._genc = QAPIGenC(blurb, pydoc)
+        self._genh = QAPIGenH(blurb, pydoc)
 
-    return (fdef, fdecl)
+    def write(self, output_dir):
+        self._genc.write(output_dir, self._prefix + self._what + '.c')
+        self._genh.write(output_dir, self._prefix + self._what + '.h')
 
 
-def close_output(fdef, fdecl):
-    fdecl.write('''
-#endif
-''')
-    fdecl.close()
-    fdef.close()
+class QAPISchemaModularCVisitor(QAPISchemaVisitor):
+
+    def __init__(self, prefix, what, blurb, pydoc):
+        self._prefix = prefix
+        self._what = what
+        self._blurb = blurb
+        self._pydoc = pydoc
+        self._module = {}
+        self._main_module = None
+
+    def _module_basename(self, what, name):
+        if name is None:
+            return re.sub(r'-', '-builtin-', what)
+        basename = os.path.join(os.path.dirname(name),
+                                self._prefix + what)
+        if name == self._main_module:
+            return basename
+        return basename + '-' + os.path.splitext(os.path.basename(name))[0]
+
+    def _add_module(self, name, blurb):
+        if self._main_module is None and name is not None:
+            self._main_module = name
+        genc = QAPIGenC(blurb, self._pydoc)
+        genh = QAPIGenH(blurb, self._pydoc)
+        self._module[name] = (genc, genh)
+        self._set_module(name)
+
+    def _set_module(self, name):
+        self._genc, self._genh = self._module[name]
+
+    def write(self, output_dir, opt_builtins=False):
+        for name in self._module:
+            if name is None and not opt_builtins:
+                continue
+            basename = self._module_basename(self._what, name)
+            (genc, genh) = self._module[name]
+            genc.write(output_dir, basename + '.c')
+            genh.write(output_dir, basename + '.h')
+
+    def _begin_module(self, name):
+        pass
+
+    def visit_module(self, name):
+        if name in self._module:
+            self._set_module(name)
+            return
+        self._add_module(name, self._blurb)
+        self._begin_module(name)
+
+    def visit_include(self, name, info):
+        basename = self._module_basename(self._what, name)
+        self._genh.preamble_add(mcgen('''
+#include "%(basename)s.h"
+''',
+                                      basename=basename))
diff --git a/scripts/qapi2texi.py b/scripts/qapi/doc.py
index bf1c57b..0ea68bf 100755..100644
--- a/scripts/qapi2texi.py
+++ b/scripts/qapi/doc.py
@@ -4,11 +4,10 @@
 # This work is licensed under the terms of the GNU LGPL, version 2+.
 # See the COPYING file in the top-level directory.
 """This script produces the documentation of a qapi schema in texinfo format"""
+
 from __future__ import print_function
 import re
-import sys
-
-import qapi
+import qapi.common
 
 MSG_FMT = """
 @deftypefn {type} {{}} {name}
@@ -197,34 +196,36 @@ def texi_entity(doc, what, base=None, variants=None,
             + texi_sections(doc))
 
 
-class QAPISchemaGenDocVisitor(qapi.QAPISchemaVisitor):
-    def __init__(self):
-        self.out = None
+class QAPISchemaGenDocVisitor(qapi.common.QAPISchemaVisitor):
+    def __init__(self, prefix):
+        self._prefix = prefix
+        self._gen = qapi.common.QAPIGenDoc()
         self.cur_doc = None
 
-    def visit_begin(self, schema):
-        self.out = ''
+    def write(self, output_dir):
+        self._gen.write(output_dir, self._prefix + 'qapi-doc.texi')
 
     def visit_enum_type(self, name, info, values, prefix):
         doc = self.cur_doc
-        self.out += TYPE_FMT(type='Enum',
-                             name=doc.symbol,
-                             body=texi_entity(doc, 'Values',
-                                              member_func=texi_enum_value))
+        self._gen.add(TYPE_FMT(type='Enum',
+                               name=doc.symbol,
+                               body=texi_entity(doc, 'Values',
+                                                member_func=texi_enum_value)))
 
     def visit_object_type(self, name, info, base, members, variants):
         doc = self.cur_doc
         if base and base.is_implicit():
             base = None
-        self.out += TYPE_FMT(type='Object',
-                             name=doc.symbol,
-                             body=texi_entity(doc, 'Members', base, variants))
+        self._gen.add(TYPE_FMT(type='Object',
+                               name=doc.symbol,
+                               body=texi_entity(doc, 'Members',
+                                                base, variants)))
 
     def visit_alternate_type(self, name, info, variants):
         doc = self.cur_doc
-        self.out += TYPE_FMT(type='Alternate',
-                             name=doc.symbol,
-                             body=texi_entity(doc, 'Members'))
+        self._gen.add(TYPE_FMT(type='Alternate',
+                               name=doc.symbol,
+                               body=texi_entity(doc, 'Members')))
 
     def visit_command(self, name, info, arg_type, ret_type,
                       gen, success_response, boxed):
@@ -236,55 +237,38 @@ class QAPISchemaGenDocVisitor(qapi.QAPISchemaVisitor):
             body += texi_sections(doc)
         else:
             body = texi_entity(doc, 'Arguments')
-        self.out += MSG_FMT(type='Command',
-                            name=doc.symbol,
-                            body=body)
+        self._gen.add(MSG_FMT(type='Command',
+                              name=doc.symbol,
+                              body=body))
 
     def visit_event(self, name, info, arg_type, boxed):
         doc = self.cur_doc
-        self.out += MSG_FMT(type='Event',
-                            name=doc.symbol,
-                            body=texi_entity(doc, 'Arguments'))
+        self._gen.add(MSG_FMT(type='Event',
+                              name=doc.symbol,
+                              body=texi_entity(doc, 'Arguments')))
 
     def symbol(self, doc, entity):
-        if self.out:
-            self.out += '\n'
+        if self._gen._body:
+            self._gen.add('\n')
         self.cur_doc = doc
         entity.visit(self)
         self.cur_doc = None
 
     def freeform(self, doc):
         assert not doc.args
-        if self.out:
-            self.out += '\n'
-        self.out += texi_body(doc) + texi_sections(doc)
+        if self._gen._body:
+            self._gen.add('\n')
+        self._gen.add(texi_body(doc) + texi_sections(doc))
 
 
-def texi_schema(schema):
-    """Convert QAPI schema documentation to Texinfo"""
-    gen = QAPISchemaGenDocVisitor()
-    gen.visit_begin(schema)
+def gen_doc(schema, output_dir, prefix):
+    if not qapi.common.doc_required:
+        return
+    vis = QAPISchemaGenDocVisitor(prefix)
+    vis.visit_begin(schema)
     for doc in schema.docs:
         if doc.symbol:
-            gen.symbol(doc, schema.lookup_entity(doc.symbol))
+            vis.symbol(doc, schema.lookup_entity(doc.symbol))
         else:
-            gen.freeform(doc)
-    return gen.out
-
-
-def main(argv):
-    """Takes schema argument, prints result to stdout"""
-    if len(argv) != 2:
-        print("%s: need exactly 1 argument: SCHEMA" % argv[0], file=sys.stderr)
-        sys.exit(1)
-
-    schema = qapi.QAPISchema(argv[1])
-    if not qapi.doc_required:
-        print("%s: need pragma 'doc-required' "
-               "to generate documentation" % argv[0], file=sys.stderr)
-        sys.exit(1)
-    print(texi_schema(schema))
-
-
-if __name__ == '__main__':
-    main(sys.argv)
+            vis.freeform(doc)
+    vis.write(output_dir)
diff --git a/scripts/qapi-event.py b/scripts/qapi/events.py
index c710968..3dc523c 100644
--- a/scripts/qapi-event.py
+++ b/scripts/qapi/events.py
@@ -1,17 +1,18 @@
-#
-# QAPI event generator
-#
-# Copyright (c) 2014 Wenchao Xia
-# Copyright (c) 2015-2016 Red Hat Inc.
-#
-# Authors:
-#  Wenchao Xia <wenchaoqemu@gmail.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 *
+"""
+QAPI event generator
+
+Copyright (c) 2014 Wenchao Xia
+Copyright (c) 2015-2018 Red Hat Inc.
+
+Authors:
+ Wenchao Xia <wenchaoqemu@gmail.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.common import *
 
 
 def build_event_send_proto(name, arg_type, boxed):
@@ -57,7 +58,7 @@ def gen_param_var(typ):
     return ret
 
 
-def gen_event_send(name, arg_type, boxed):
+def gen_event_send(name, arg_type, boxed, event_enum_name):
     # FIXME: Our declaration of local variables (and of 'errp' in the
     # parameter list) can collide with exploded members of the event's
     # data type passed in as parameters.  If this collision ever hits in
@@ -147,89 +148,48 @@ out:
     return ret
 
 
-class QAPISchemaGenEventVisitor(QAPISchemaVisitor):
-    def __init__(self):
-        self.decl = None
-        self.defn = None
-        self._event_names = None
+class QAPISchemaGenEventVisitor(QAPISchemaModularCVisitor):
 
-    def visit_begin(self, schema):
-        self.decl = ''
-        self.defn = ''
+    def __init__(self, prefix):
+        QAPISchemaModularCVisitor.__init__(
+            self, prefix, 'qapi-events',
+            ' * Schema-defined QAPI/QMP events', __doc__)
+        self._enum_name = c_name(prefix + 'QAPIEvent', protect=False)
         self._event_names = []
 
-    def visit_end(self):
-        self.decl += gen_enum(event_enum_name, self._event_names)
-        self.defn += gen_enum_lookup(event_enum_name, self._event_names)
-        self._event_names = None
-
-    def visit_event(self, name, info, arg_type, boxed):
-        self.decl += gen_event_send_decl(name, arg_type, boxed)
-        self.defn += gen_event_send(name, arg_type, boxed)
-        self._event_names.append(name)
-
-
-(input_file, output_dir, do_c, do_h, prefix, dummy) = parse_command_line()
-
-c_comment = '''
-/*
- * schema-defined QAPI event functions
- *
- * Copyright (c) 2014 Wenchao Xia
- *
- * Authors:
- *  Wenchao Xia   <wenchaoqemu@gmail.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 event functions
- *
- * Copyright (c) 2014 Wenchao Xia
- *
- * Authors:
- *  Wenchao Xia  <wenchaoqemu@gmail.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-event.c', 'qapi-event.h',
-                            c_comment, h_comment)
-
-fdef.write(mcgen('''
+    def _begin_module(self, name):
+        types = self._module_basename('qapi-types', name)
+        visit = self._module_basename('qapi-visit', name)
+        self._genc.add(mcgen('''
 #include "qemu/osdep.h"
 #include "qemu-common.h"
-#include "%(prefix)sqapi-event.h"
-#include "%(prefix)sqapi-visit.h"
+#include "%(prefix)sqapi-events.h"
+#include "%(visit)s.h"
 #include "qapi/error.h"
 #include "qapi/qmp/qdict.h"
 #include "qapi/qobject-output-visitor.h"
 #include "qapi/qmp-event.h"
 
 ''',
-                 prefix=prefix))
-
-fdecl.write(mcgen('''
+                             visit=visit, prefix=self._prefix))
+        self._genh.add(mcgen('''
 #include "qapi/util.h"
-#include "%(prefix)sqapi-types.h"
+#include "%(types)s.h"
 
 ''',
-                  prefix=prefix))
+                             types=types))
 
-event_enum_name = c_name(prefix + 'QAPIEvent', protect=False)
+    def visit_end(self):
+        self._genh.add(gen_enum(self._enum_name, self._event_names))
+        self._genc.add(gen_enum_lookup(self._enum_name, self._event_names))
+
+    def visit_event(self, name, info, arg_type, boxed):
+        self._genh.add(gen_event_send_decl(name, arg_type, boxed))
+        self._genc.add(gen_event_send(name, arg_type, boxed, self._enum_name))
+        self._event_names.append(name)
 
-schema = QAPISchema(input_file)
-gen = QAPISchemaGenEventVisitor()
-schema.visit(gen)
-fdef.write(gen.defn)
-fdecl.write(gen.decl)
 
-close_output(fdef, fdecl)
+def gen_events(schema, output_dir, prefix):
+    vis = QAPISchemaGenEventVisitor(prefix)
+    schema.visit(vis)
+    vis.write(output_dir)
diff --git a/scripts/qapi-introspect.py b/scripts/qapi/introspect.py
index 032bcea..f66c397 100644
--- a/scripts/qapi-introspect.py
+++ b/scripts/qapi/introspect.py
@@ -1,15 +1,16 @@
-#
-# QAPI introspection generator
-#
-# Copyright (C) 2015-2016 Red Hat, Inc.
-#
-# Authors:
-#  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.
+"""
+QAPI introspection generator
 
-from qapi import *
+Copyright (C) 2015-2018 Red Hat, Inc.
+
+Authors:
+ 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.common import *
 
 
 # Caveman's json.dumps() replacement (we're stuck at Python 2.4)
@@ -39,21 +40,26 @@ def to_c_string(string):
     return '"' + string.replace('\\', r'\\').replace('"', r'\"') + '"'
 
 
-class QAPISchemaGenIntrospectVisitor(QAPISchemaVisitor):
-    def __init__(self, unmask):
+class QAPISchemaGenIntrospectVisitor(QAPISchemaMonolithicCVisitor):
+
+    def __init__(self, prefix, unmask):
+        QAPISchemaMonolithicCVisitor.__init__(
+            self, prefix, 'qapi-introspect',
+            ' * QAPI/QMP schema introspection', __doc__)
         self._unmask = unmask
-        self.defn = None
-        self.decl = None
         self._schema = None
-        self._jsons = None
-        self._used_types = None
-        self._name_map = None
-
-    def visit_begin(self, schema):
-        self._schema = schema
         self._jsons = []
         self._used_types = []
         self._name_map = {}
+        self._genc.add(mcgen('''
+#include "qemu/osdep.h"
+#include "%(prefix)sqapi-introspect.h"
+
+''',
+                             prefix=prefix))
+
+    def visit_begin(self, schema):
+        self._schema = schema
 
     def visit_end(self):
         # visit the types that are actually used
@@ -64,22 +70,22 @@ class QAPISchemaGenIntrospectVisitor(QAPISchemaVisitor):
         # generate C
         # TODO can generate awfully long lines
         jsons.extend(self._jsons)
-        name = c_name(prefix, protect=False) + 'qmp_schema_json'
-        self.decl = mcgen('''
+        name = c_name(self._prefix, protect=False) + 'qmp_schema_json'
+        self._genh.add(mcgen('''
 extern const char %(c_name)s[];
 ''',
-                          c_name=c_name(name))
+                             c_name=c_name(name)))
         lines = to_json(jsons).split('\n')
         c_string = '\n    '.join([to_c_string(line) for line in lines])
-        self.defn = mcgen('''
+        self._genc.add(mcgen('''
 const char %(c_name)s[] = %(c_string)s;
 ''',
-                          c_name=c_name(name),
-                          c_string=c_string)
+                             c_name=c_name(name),
+                             c_string=c_string))
         self._schema = None
-        self._jsons = None
-        self._used_types = None
-        self._name_map = None
+        self._jsons = []
+        self._used_types = []
+        self._name_map = {}
 
     def visit_needed(self, entity):
         # Ignore types on first pass; visit_end() will pick up used types
@@ -165,55 +171,8 @@ const char %(c_name)s[] = %(c_string)s;
         arg_type = arg_type or self._schema.the_empty_object_type
         self._gen_json(name, 'event', {'arg-type': self._use_type(arg_type)})
 
-# Debugging aid: unmask QAPI schema's type names
-# We normally mask them, because they're not QMP wire ABI
-opt_unmask = False
-
-(input_file, output_dir, do_c, do_h, prefix, opts) = \
-    parse_command_line('u', ['unmask-non-abi-names'])
-
-for o, a in opts:
-    if o in ('-u', '--unmask-non-abi-names'):
-        opt_unmask = True
-
-c_comment = '''
-/*
- * QAPI/QMP schema introspection
- *
- * Copyright (C) 2015 Red Hat, Inc.
- *
- * 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 = '''
-/*
- * QAPI/QMP schema introspection
- *
- * Copyright (C) 2015 Red Hat, Inc.
- *
- * 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,
-                            'qmp-introspect.c', 'qmp-introspect.h',
-                            c_comment, h_comment)
-
-fdef.write(mcgen('''
-#include "qemu/osdep.h"
-#include "%(prefix)sqmp-introspect.h"
-
-''',
-                 prefix=prefix))
-
-schema = QAPISchema(input_file)
-gen = QAPISchemaGenIntrospectVisitor(opt_unmask)
-schema.visit(gen)
-fdef.write(gen.defn)
-fdecl.write(gen.decl)
 
-close_output(fdef, fdecl)
+def gen_introspect(schema, output_dir, prefix, opt_unmask):
+    vis = QAPISchemaGenIntrospectVisitor(prefix, opt_unmask)
+    schema.visit(vis)
+    vis.write(output_dir)
diff --git a/scripts/qapi-types.py b/scripts/qapi/types.py
index 7e3051d..64d9c0f 100644
--- a/scripts/qapi-types.py
+++ b/scripts/qapi/types.py
@@ -1,17 +1,19 @@
-#
-# 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.
+"""
+QAPI types generator
+
+Copyright IBM, Corp. 2011
+Copyright (c) 2013-2018 Red Hat Inc.
+
+Authors:
+ Anthony Liguori <aliguori@us.ibm.com>
+ Michael Roth <mdroth@linux.vnet.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 *
+from qapi.common import *
 
 
 # variants must be emitted before their container; track what has already
@@ -165,67 +167,62 @@ void qapi_free_%(c_name)s(%(c_name)s *obj)
     return ret
 
 
-class QAPISchemaGenTypeVisitor(QAPISchemaVisitor):
-    def __init__(self):
-        self.decl = None
-        self.defn = None
-        self._fwdecl = None
-        self._btin = None
+class QAPISchemaGenTypeVisitor(QAPISchemaModularCVisitor):
+
+    def __init__(self, prefix):
+        QAPISchemaModularCVisitor.__init__(
+            self, prefix, 'qapi-types', ' * Schema-defined QAPI types',
+            __doc__)
+        self._add_module(None, ' * Built-in QAPI types')
+        self._genc.preamble_add(mcgen('''
+#include "qemu/osdep.h"
+#include "qapi/dealloc-visitor.h"
+#include "qapi/qapi-builtin-types.h"
+#include "qapi/qapi-builtin-visit.h"
+'''))
+        self._genh.preamble_add(mcgen('''
+#include "qapi/util.h"
+'''))
+
+    def _begin_module(self, name):
+        types = self._module_basename('qapi-types', name)
+        visit = self._module_basename('qapi-visit', name)
+        self._genc.preamble_add(mcgen('''
+#include "qemu/osdep.h"
+#include "qapi/dealloc-visitor.h"
+#include "%(types)s.h"
+#include "%(visit)s.h"
+''',
+                                      types=types, visit=visit))
+        self._genh.preamble_add(mcgen('''
+#include "qapi/qapi-builtin-types.h"
+'''))
 
     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)
+        self._genh.add(gen_type_cleanup_decl(name))
+        self._genc.add(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)
+        self._genh.preamble_add(gen_enum(name, values, prefix))
+        self._genc.add(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)
+        self._genh.preamble_add(gen_fwd_object_or_array(name))
+        self._genh.add(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)
+        self._genh.preamble_add(gen_fwd_object_or_array(name))
+        self._genh.add(gen_object(name, base, members, variants))
         if base and not base.is_implicit():
-            self.decl += gen_upcast(name, base)
+            self._genh.add(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_'):
@@ -233,73 +230,13 @@ class QAPISchemaGenTypeVisitor(QAPISchemaVisitor):
             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._genh.preamble_add(gen_fwd_object_or_array(name))
+        self._genh.add(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))
-
-fdecl.write(mcgen('''
-#include "qapi/util.h"
-'''))
-
-schema = QAPISchema(input_file)
-gen = QAPISchemaGenTypeVisitor()
-schema.visit(gen)
-fdef.write(gen.defn)
-fdecl.write(gen.decl)
 
-close_output(fdef, fdecl)
+def gen_types(schema, output_dir, prefix, opt_builtins):
+    vis = QAPISchemaGenTypeVisitor(prefix)
+    schema.visit(vis)
+    vis.write(output_dir, opt_builtins)
diff --git a/scripts/qapi-visit.py b/scripts/qapi/visit.py
index 7e1cfc1..5d72d89 100644
--- a/scripts/qapi-visit.py
+++ b/scripts/qapi/visit.py
@@ -1,18 +1,19 @@
-#
-# QAPI visitor generator
-#
-# Copyright IBM, Corp. 2011
-# Copyright (C) 2014-2016 Red Hat, Inc.
-#
-# Authors:
-#  Anthony Liguori <aliguori@us.ibm.com>
-#  Michael Roth    <mdroth@linux.vnet.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 *
+"""
+QAPI visitor generator
+
+Copyright IBM, Corp. 2011
+Copyright (C) 2014-2018 Red Hat, Inc.
+
+Authors:
+ Anthony Liguori <aliguori@us.ibm.com>
+ Michael Roth    <mdroth@linux.vnet.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.common import *
 
 
 def gen_visit_decl(name, scalar=False):
@@ -262,131 +263,71 @@ out:
                  c_name=c_name(name))
 
 
-class QAPISchemaGenVisitVisitor(QAPISchemaVisitor):
-    def __init__(self):
-        self.decl = None
-        self.defn = None
-        self._btin = None
+class QAPISchemaGenVisitVisitor(QAPISchemaModularCVisitor):
+
+    def __init__(self, prefix):
+        QAPISchemaModularCVisitor.__init__(
+            self, prefix, 'qapi-visit', ' * Schema-defined QAPI visitors',
+            __doc__)
+        self._add_module(None, ' * Built-in QAPI visitors')
+        self._genc.preamble_add(mcgen('''
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "qapi/error.h"
+#include "qapi/qapi-builtin-visit.h"
+'''))
+        self._genh.preamble_add(mcgen('''
+#include "qapi/visitor.h"
+#include "qapi/qapi-builtin-types.h"
+
+''',
+                                      prefix=prefix))
 
-    def visit_begin(self, schema):
-        self.decl = ''
-        self.defn = ''
-        self._btin = guardstart('QAPI_VISIT_BUILTIN')
+    def _begin_module(self, name):
+        types = self._module_basename('qapi-types', name)
+        visit = self._module_basename('qapi-visit', name)
+        self._genc.preamble_add(mcgen('''
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "qapi/error.h"
+#include "qapi/qmp/qerror.h"
+#include "%(visit)s.h"
+''',
+                                      visit=visit, prefix=self._prefix))
+        self._genh.preamble_add(mcgen('''
+#include "qapi/qapi-builtin-visit.h"
+#include "%(types)s.h"
 
-    def visit_end(self):
-        # 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_VISIT_BUILTIN')
-        self.decl = self._btin + self.decl
-        self._btin = None
+''',
+                                      types=types))
 
     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_visit_decl(name, scalar=True)
-            if do_builtins:
-                self.defn += gen_visit_enum(name)
-        else:
-            self.decl += gen_visit_decl(name, scalar=True)
-            self.defn += gen_visit_enum(name)
+        self._genh.add(gen_visit_decl(name, scalar=True))
+        self._genc.add(gen_visit_enum(name))
 
     def visit_array_type(self, name, info, element_type):
-        decl = gen_visit_decl(name)
-        defn = gen_visit_list(name, element_type)
-        if isinstance(element_type, QAPISchemaBuiltinType):
-            self._btin += decl
-            if do_builtins:
-                self.defn += defn
-        else:
-            self.decl += decl
-            self.defn += defn
+        self._genh.add(gen_visit_decl(name))
+        self._genc.add(gen_visit_list(name, element_type))
 
     def visit_object_type(self, name, info, base, members, variants):
         # Nothing to do for the special empty builtin
         if name == 'q_empty':
             return
-        self.decl += gen_visit_members_decl(name)
-        self.defn += gen_visit_object_members(name, base, members, variants)
+        self._genh.add(gen_visit_members_decl(name))
+        self._genc.add(gen_visit_object_members(name, base, members, variants))
         # TODO Worth changing the visitor signature, so we could
         # directly use rather than repeat type.is_implicit()?
         if not name.startswith('q_'):
             # only explicit types need an allocating visit
-            self.decl += gen_visit_decl(name)
-            self.defn += gen_visit_object(name, base, members, variants)
+            self._genh.add(gen_visit_decl(name))
+            self._genc.add(gen_visit_object(name, base, members, variants))
 
     def visit_alternate_type(self, name, info, variants):
-        self.decl += gen_visit_decl(name)
-        self.defn += gen_visit_alternate(name, variants)
-
-# 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
-# QAPISchemaGenVisitVisitor.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 = '''
-/*
- * schema-defined QAPI visitor functions
- *
- * 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.
- *
- */
-'''
-h_comment = '''
-/*
- * schema-defined QAPI visitor functions
- *
- * 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-visit.c', 'qapi-visit.h',
-                            c_comment, h_comment)
-
-fdef.write(mcgen('''
-#include "qemu/osdep.h"
-#include "qemu-common.h"
-#include "qapi/error.h"
-#include "%(prefix)sqapi-visit.h"
-''',
-                 prefix=prefix))
-
-fdecl.write(mcgen('''
-#include "qapi/visitor.h"
-#include "qapi/qmp/qerror.h"
-#include "%(prefix)sqapi-types.h"
-
-''',
-                  prefix=prefix))
+        self._genh.add(gen_visit_decl(name))
+        self._genc.add(gen_visit_alternate(name, variants))
 
-schema = QAPISchema(input_file)
-gen = QAPISchemaGenVisitVisitor()
-schema.visit(gen)
-fdef.write(gen.defn)
-fdecl.write(gen.decl)
 
-close_output(fdef, fdecl)
+def gen_visit(schema, output_dir, prefix, opt_builtins):
+    vis = QAPISchemaGenVisitVisitor(prefix)
+    schema.visit(vis)
+    vis.write(output_dir, opt_builtins)