]> git.proxmox.com Git - mirror_qemu.git/blobdiff - scripts/qapi.py
qapi: add qapi2texi script
[mirror_qemu.git] / scripts / qapi.py
index 9d532553209089a170e984d679a0ad0387d17ac1..53a44779d0b513c011916d044ba76fb88fe481ac 100644 (file)
@@ -2,7 +2,7 @@
 # QAPI helper library
 #
 # Copyright IBM, Corp. 2011
-# Copyright (c) 2013-2015 Red Hat Inc.
+# Copyright (c) 2013-2016 Red Hat Inc.
 #
 # Authors:
 #  Anthony Liguori <aliguori@us.ibm.com>
@@ -33,7 +33,8 @@ builtin_types = {
     'uint32':   'QTYPE_QINT',
     'uint64':   'QTYPE_QINT',
     'size':     'QTYPE_QINT',
-    'any':      None,           # any qtype_code possible, actually
+    'any':      None,           # any QType possible, actually
+    'QType':    'QTYPE_QSTRING',
 }
 
 # Whitelist of commands allowed to return a non-dictionary
@@ -58,6 +59,18 @@ returns_whitelist = [
     'guest-sync-delimited',
 ]
 
+# Whitelist of entities allowed to violate case conventions
+case_whitelist = [
+    # From QMP:
+    'ACPISlotType',         # DIMM, visible through query-acpi-ospm-status
+    'CpuInfoMIPS',          # PC, visible through query-cpu
+    'CpuInfoTricore',       # PC, visible through query-cpu
+    'QapiErrorClass',       # all members, visible through errors
+    'UuidInfo',             # UUID, visible through query-uuid
+    'X86CPURegister32',     # all members, visible indirectly through qom-get
+    'q_obj_CpuInfo-base',   # CPU, visible through query-cpu
+]
+
 enum_types = []
 struct_types = []
 union_types = []
@@ -78,35 +91,154 @@ def error_path(parent):
     return res
 
 
-class QAPISchemaError(Exception):
-    def __init__(self, schema, msg):
+class QAPIError(Exception):
+    def __init__(self, fname, line, col, incl_info, msg):
         Exception.__init__(self)
-        self.fname = schema.fname
+        self.fname = fname
+        self.line = line
+        self.col = col
+        self.info = incl_info
         self.msg = msg
-        self.col = 1
-        self.line = schema.line
-        for ch in schema.src[schema.line_pos:schema.pos]:
+
+    def __str__(self):
+        loc = "%s:%d" % (self.fname, self.line)
+        if self.col is not None:
+            loc += ":%s" % self.col
+        return error_path(self.info) + "%s: %s" % (loc, self.msg)
+
+
+class QAPIParseError(QAPIError):
+    def __init__(self, parser, msg):
+        col = 1
+        for ch in parser.src[parser.line_pos:parser.pos]:
             if ch == '\t':
-                self.col = (self.col + 7) % 8 + 1
+                col = (col + 7) % 8 + 1
             else:
-                self.col += 1
-        self.info = schema.incl_info
+                col += 1
+        QAPIError.__init__(self, parser.fname, parser.line, col,
+                           parser.incl_info, msg)
 
-    def __str__(self):
-        return error_path(self.info) + \
-            "%s:%d:%d: %s" % (self.fname, self.line, self.col, self.msg)
 
+class QAPISemError(QAPIError):
+    def __init__(self, info, msg):
+        QAPIError.__init__(self, info['file'], info['line'], None,
+                           info['parent'], msg)
 
-class QAPIExprError(Exception):
-    def __init__(self, expr_info, msg):
-        Exception.__init__(self)
-        assert expr_info
-        self.info = expr_info
-        self.msg = msg
 
-    def __str__(self):
-        return error_path(self.info['parent']) + \
-            "%s:%d: %s" % (self.info['file'], self.info['line'], self.msg)
+class QAPIDoc(object):
+    class Section(object):
+        def __init__(self, name=None):
+            # optional section name (argument/member or section name)
+            self.name = name
+            # the list of lines for this section
+            self.content = []
+
+        def append(self, line):
+            self.content.append(line)
+
+        def __repr__(self):
+            return "\n".join(self.content).strip()
+
+    class ArgSection(Section):
+        pass
+
+    def __init__(self, parser, info):
+        # self.parser is used to report errors with QAPIParseError.  The
+        # resulting error position depends on the state of the parser.
+        # It happens to be the beginning of the comment.  More or less
+        # servicable, but action at a distance.
+        self.parser = parser
+        self.info = info
+        self.symbol = None
+        self.body = QAPIDoc.Section()
+        # dict mapping parameter name to ArgSection
+        self.args = OrderedDict()
+        # a list of Section
+        self.sections = []
+        # the current section
+        self.section = self.body
+        # associated expression (to be set by expression parser)
+        self.expr = None
+
+    def has_section(self, name):
+        """Return True if we have a section with this name."""
+        for i in self.sections:
+            if i.name == name:
+                return True
+        return False
+
+    def append(self, line):
+        """Parse a comment line and add it to the documentation."""
+        line = line[1:]
+        if not line:
+            self._append_freeform(line)
+            return
+
+        if line[0] != ' ':
+            raise QAPIParseError(self.parser, "Missing space after #")
+        line = line[1:]
+
+        # FIXME not nice: things like '#  @foo:' and '# @foo: ' aren't
+        # recognized, and get silently treated as ordinary text
+        if self.symbol:
+            self._append_symbol_line(line)
+        elif not self.body.content and line.startswith("@"):
+            if not line.endswith(":"):
+                raise QAPIParseError(self.parser, "Line should end with :")
+            self.symbol = line[1:-1]
+            # FIXME invalid names other than the empty string aren't flagged
+            if not self.symbol:
+                raise QAPIParseError(self.parser, "Invalid name")
+        else:
+            self._append_freeform(line)
+
+    def _append_symbol_line(self, line):
+        name = line.split(' ', 1)[0]
+
+        if name.startswith("@") and name.endswith(":"):
+            line = line[len(name)+1:]
+            self._start_args_section(name[1:-1])
+        elif name in ("Returns:", "Since:",
+                      # those are often singular or plural
+                      "Note:", "Notes:",
+                      "Example:", "Examples:",
+                      "TODO:"):
+            line = line[len(name)+1:]
+            self._start_section(name[:-1])
+
+        self._append_freeform(line)
+
+    def _start_args_section(self, name):
+        # FIXME invalid names other than the empty string aren't flagged
+        if not name:
+            raise QAPIParseError(self.parser, "Invalid parameter name")
+        if name in self.args:
+            raise QAPIParseError(self.parser,
+                                 "'%s' parameter name duplicated" % name)
+        if self.sections:
+            raise QAPIParseError(self.parser,
+                                 "'@%s:' can't follow '%s' section"
+                                 % (name, self.sections[0].name))
+        self.section = QAPIDoc.ArgSection(name)
+        self.args[name] = self.section
+
+    def _start_section(self, name=""):
+        if name in ("Returns", "Since") and self.has_section(name):
+            raise QAPIParseError(self.parser,
+                                 "Duplicated '%s' section" % name)
+        self.section = QAPIDoc.Section(name)
+        self.sections.append(self.section)
+
+    def _append_freeform(self, line):
+        in_arg = isinstance(self.section, QAPIDoc.ArgSection)
+        if (in_arg and self.section.content
+                and not self.section.content[-1]
+                and line and not line[0].isspace()):
+            self._start_section()
+        if (in_arg or not self.section.name
+                or not self.section.name.startswith("Example")):
+            line = line.strip()
+        self.section.append(line)
 
 
 class QAPISchemaParser(object):
@@ -124,46 +256,58 @@ class QAPISchemaParser(object):
         self.line = 1
         self.line_pos = 0
         self.exprs = []
+        self.docs = []
         self.accept()
 
         while self.tok is not None:
-            expr_info = {'file': fname, 'line': self.line,
-                         'parent': self.incl_info}
+            info = {'file': fname, 'line': self.line,
+                    'parent': self.incl_info}
+            if self.tok == '#':
+                doc = self.get_doc(info)
+                self.docs.append(doc)
+                continue
+
             expr = self.get_expr(False)
             if isinstance(expr, dict) and "include" in expr:
                 if len(expr) != 1:
-                    raise QAPIExprError(expr_info,
-                                        "Invalid 'include' directive")
+                    raise QAPISemError(info, "Invalid 'include' directive")
                 include = expr["include"]
                 if not isinstance(include, str):
-                    raise QAPIExprError(expr_info,
-                                        "Value of 'include' must be a string")
+                    raise QAPISemError(info,
+                                       "Value of 'include' must be a string")
                 incl_abs_fname = os.path.join(os.path.dirname(abs_fname),
                                               include)
                 # catch inclusion cycle
-                inf = expr_info
+                inf = info
                 while inf:
                     if incl_abs_fname == os.path.abspath(inf['file']):
-                        raise QAPIExprError(expr_info, "Inclusion loop for %s"
-                                            % include)
+                        raise QAPISemError(info, "Inclusion loop for %s"
+                                           % include)
                     inf = inf['parent']
+
                 # skip multiple include of the same file
                 if incl_abs_fname in previously_included:
                     continue
                 try:
                     fobj = open(incl_abs_fname, 'r')
-                except IOError, e:
-                    raise QAPIExprError(expr_info,
-                                        '%s: %s' % (e.strerror, include))
+                except IOError as e:
+                    raise QAPISemError(info, '%s: %s' % (e.strerror, include))
                 exprs_include = QAPISchemaParser(fobj, previously_included,
-                                                 expr_info)
+                                                 info)
                 self.exprs.extend(exprs_include.exprs)
+                self.docs.extend(exprs_include.docs)
             else:
                 expr_elem = {'expr': expr,
-                             'info': expr_info}
+                             'info': info}
+                if (self.docs
+                        and self.docs[-1].info['file'] == fname
+                        and not self.docs[-1].expr):
+                    self.docs[-1].expr = expr
+                    expr_elem['doc'] = self.docs[-1]
+
                 self.exprs.append(expr_elem)
 
-    def accept(self):
+    def accept(self, skip_comment=True):
         while True:
             self.tok = self.src[self.cursor]
             self.pos = self.cursor
@@ -171,8 +315,14 @@ class QAPISchemaParser(object):
             self.val = None
 
             if self.tok == '#':
+                if self.src[self.cursor] == '#':
+                    # Start of doc comment
+                    skip_comment = False
                 self.cursor = self.src.find('\n', self.cursor)
-            elif self.tok in ['{', '}', ':', ',', '[', ']']:
+                if not skip_comment:
+                    self.val = self.src[self.pos:self.cursor]
+                    return
+            elif self.tok in "{}:,[]":
                 return
             elif self.tok == "'":
                 string = ''
@@ -181,8 +331,7 @@ class QAPISchemaParser(object):
                     ch = self.src[self.cursor]
                     self.cursor += 1
                     if ch == '\n':
-                        raise QAPISchemaError(self,
-                                              'Missing terminating "\'"')
+                        raise QAPIParseError(self, 'Missing terminating "\'"')
                     if esc:
                         if ch == 'b':
                             string += '\b'
@@ -200,25 +349,25 @@ class QAPISchemaParser(object):
                                 ch = self.src[self.cursor]
                                 self.cursor += 1
                                 if ch not in "0123456789abcdefABCDEF":
-                                    raise QAPISchemaError(self,
-                                                          '\\u escape needs 4 '
-                                                          'hex digits')
+                                    raise QAPIParseError(self,
+                                                         '\\u escape needs 4 '
+                                                         'hex digits')
                                 value = (value << 4) + int(ch, 16)
                             # If Python 2 and 3 didn't disagree so much on
                             # how to handle Unicode, then we could allow
                             # Unicode string defaults.  But most of QAPI is
                             # ASCII-only, so we aren't losing much for now.
                             if not value or value > 0x7f:
-                                raise QAPISchemaError(self,
-                                                      'For now, \\u escape '
-                                                      'only supports non-zero '
-                                                      'values up to \\u007f')
+                                raise QAPIParseError(self,
+                                                     'For now, \\u escape '
+                                                     'only supports non-zero '
+                                                     'values up to \\u007f')
                             string += chr(value)
                         elif ch in "\\/'\"":
                             string += ch
                         else:
-                            raise QAPISchemaError(self,
-                                                  "Unknown escape \\%s" % ch)
+                            raise QAPIParseError(self,
+                                                 "Unknown escape \\%s" % ch)
                         esc = False
                     elif ch == "\\":
                         esc = True
@@ -246,7 +395,7 @@ class QAPISchemaParser(object):
                 self.line += 1
                 self.line_pos = self.cursor
             elif not self.tok.isspace():
-                raise QAPISchemaError(self, 'Stray "%s"' % self.tok)
+                raise QAPIParseError(self, 'Stray "%s"' % self.tok)
 
     def get_members(self):
         expr = OrderedDict()
@@ -254,24 +403,24 @@ class QAPISchemaParser(object):
             self.accept()
             return expr
         if self.tok != "'":
-            raise QAPISchemaError(self, 'Expected string or "}"')
+            raise QAPIParseError(self, 'Expected string or "}"')
         while True:
             key = self.val
             self.accept()
             if self.tok != ':':
-                raise QAPISchemaError(self, 'Expected ":"')
+                raise QAPIParseError(self, 'Expected ":"')
             self.accept()
             if key in expr:
-                raise QAPISchemaError(self, 'Duplicate key "%s"' % key)
+                raise QAPIParseError(self, 'Duplicate key "%s"' % key)
             expr[key] = self.get_expr(True)
             if self.tok == '}':
                 self.accept()
                 return expr
             if self.tok != ',':
-                raise QAPISchemaError(self, 'Expected "," or "}"')
+                raise QAPIParseError(self, 'Expected "," or "}"')
             self.accept()
             if self.tok != "'":
-                raise QAPISchemaError(self, 'Expected string')
+                raise QAPIParseError(self, 'Expected string')
 
     def get_values(self):
         expr = []
@@ -279,20 +428,20 @@ class QAPISchemaParser(object):
             self.accept()
             return expr
         if self.tok not in "{['tfn":
-            raise QAPISchemaError(self, 'Expected "{", "[", "]", string, '
-                                  'boolean or "null"')
+            raise QAPIParseError(self, 'Expected "{", "[", "]", string, '
+                                 'boolean or "null"')
         while True:
             expr.append(self.get_expr(True))
             if self.tok == ']':
                 self.accept()
                 return expr
             if self.tok != ',':
-                raise QAPISchemaError(self, 'Expected "," or "]"')
+                raise QAPIParseError(self, 'Expected "," or "]"')
             self.accept()
 
     def get_expr(self, nested):
         if self.tok != '{' and not nested:
-            raise QAPISchemaError(self, 'Expected "{"')
+            raise QAPIParseError(self, 'Expected "{"')
         if self.tok == '{':
             self.accept()
             expr = self.get_members()
@@ -303,9 +452,31 @@ class QAPISchemaParser(object):
             expr = self.val
             self.accept()
         else:
-            raise QAPISchemaError(self, 'Expected "{", "[" or string')
+            raise QAPIParseError(self, 'Expected "{", "[" or string')
         return expr
 
+    def get_doc(self, info):
+        if self.val != '##':
+            raise QAPIParseError(self, "Junk after '##' at start of "
+                                 "documentation comment")
+
+        doc = QAPIDoc(self, info)
+        self.accept(False)
+        while self.tok == '#':
+            if self.val.startswith('##'):
+                # End of doc comment
+                if self.val != '##':
+                    raise QAPIParseError(self, "Junk after '##' at end of "
+                                         "documentation comment")
+                self.accept()
+                return doc
+            else:
+                doc.append(self.val)
+            self.accept(False)
+
+        raise QAPIParseError(self, "Documentation comment must end with '##'")
+
+
 #
 # Semantic analysis of schema expressions
 # TODO fold into QAPISchema
@@ -313,7 +484,9 @@ class QAPISchemaParser(object):
 #
 
 
-def find_base_fields(base):
+def find_base_members(base):
+    if isinstance(base, dict):
+        return base
     base_struct_define = find_struct(base)
     if not base_struct_define:
         return None
@@ -342,43 +515,45 @@ def discriminator_find_enum_define(expr):
     if not (discriminator and base):
         return None
 
-    base_fields = find_base_fields(base)
-    if not base_fields:
+    base_members = find_base_members(base)
+    if not base_members:
         return None
 
-    discriminator_type = base_fields.get(discriminator)
+    discriminator_type = base_members.get(discriminator)
     if not discriminator_type:
         return None
 
     return find_enum(discriminator_type)
 
 
-# FIXME should enforce "other than downstream extensions [...], all
-# names should begin with a letter".
-valid_name = re.compile('^[a-zA-Z_][a-zA-Z0-9_.-]*$')
+# Names must be letters, numbers, -, and _.  They must start with letter,
+# except for downstream extensions which must start with __RFQDN_.
+# Dots are only valid in the downstream extension prefix.
+valid_name = re.compile('^(__[a-zA-Z0-9.-]+_)?'
+                        '[a-zA-Z][a-zA-Z0-9_-]*$')
 
 
-def check_name(expr_info, source, name, allow_optional=False,
+def check_name(info, source, name, allow_optional=False,
                enum_member=False):
     global valid_name
     membername = name
 
     if not isinstance(name, str):
-        raise QAPIExprError(expr_info,
-                            "%s requires a string name" % source)
+        raise QAPISemError(info, "%s requires a string name" % source)
     if name.startswith('*'):
         membername = name[1:]
         if not allow_optional:
-            raise QAPIExprError(expr_info,
-                                "%s does not allow optional name '%s'"
-                                % (source, name))
+            raise QAPISemError(info, "%s does not allow optional name '%s'"
+                               % (source, name))
     # Enum members can start with a digit, because the generated C
     # code always prefixes it with the enum name
-    if enum_member:
-        membername = '_' + membername
-    if not valid_name.match(membername):
-        raise QAPIExprError(expr_info,
-                            "%s uses invalid name '%s'" % (source, name))
+    if enum_member and membername[0].isdigit():
+        membername = 'D' + membername
+    # Reserve the entire 'q_' namespace for c_name(), and for 'q_empty'
+    # and 'q_obj_*' implicit type names.
+    if not valid_name.match(membername) or \
+       c_name(membername, False).startswith('q_'):
+        raise QAPISemError(info, "%s uses invalid name '%s'" % (source, name))
 
 
 def add_name(name, info, meta, implicit=False):
@@ -387,13 +562,11 @@ def add_name(name, info, meta, implicit=False):
     # FIXME should reject names that differ only in '_' vs. '.'
     # vs. '-', because they're liable to clash in generated C.
     if name in all_names:
-        raise QAPIExprError(info,
-                            "%s '%s' is already defined"
-                            % (all_names[name], name))
-    if not implicit and name[-4:] == 'Kind':
-        raise QAPIExprError(info,
-                            "%s '%s' should not end in 'Kind'"
-                            % (meta, name))
+        raise QAPISemError(info, "%s '%s' is already defined"
+                           % (all_names[name], name))
+    if not implicit and (name.endswith('Kind') or name.endswith('List')):
+        raise QAPISemError(info, "%s '%s' should not end in '%s'"
+                           % (meta, name, name[-4:]))
     all_names[name] = meta
 
 
@@ -445,7 +618,7 @@ def is_enum(name):
     return find_enum(name) is not None
 
 
-def check_type(expr_info, source, value, allow_array=False,
+def check_type(info, source, value, allow_array=False,
                allow_dict=False, allow_optional=False,
                allow_metas=[]):
     global all_names
@@ -456,93 +629,82 @@ def check_type(expr_info, source, value, allow_array=False,
     # Check if array type for value is okay
     if isinstance(value, list):
         if not allow_array:
-            raise QAPIExprError(expr_info,
-                                "%s cannot be an array" % source)
+            raise QAPISemError(info, "%s cannot be an array" % source)
         if len(value) != 1 or not isinstance(value[0], str):
-            raise QAPIExprError(expr_info,
-                                "%s: array type must contain single type name"
-                                % source)
+            raise QAPISemError(info,
+                               "%s: array type must contain single type name" %
+                               source)
         value = value[0]
 
     # Check if type name for value is okay
     if isinstance(value, str):
         if value not in all_names:
-            raise QAPIExprError(expr_info,
-                                "%s uses unknown type '%s'"
-                                % (source, value))
+            raise QAPISemError(info, "%s uses unknown type '%s'"
+                               % (source, value))
         if not all_names[value] in allow_metas:
-            raise QAPIExprError(expr_info,
-                                "%s cannot use %s type '%s'"
-                                % (source, all_names[value], value))
+            raise QAPISemError(info, "%s cannot use %s type '%s'" %
+                               (source, all_names[value], value))
         return
 
     if not allow_dict:
-        raise QAPIExprError(expr_info,
-                            "%s should be a type name" % source)
+        raise QAPISemError(info, "%s should be a type name" % source)
 
     if not isinstance(value, OrderedDict):
-        raise QAPIExprError(expr_info,
-                            "%s should be a dictionary or type name" % source)
+        raise QAPISemError(info,
+                           "%s should be a dictionary or type name" % source)
 
     # value is a dictionary, check that each member is okay
     for (key, arg) in value.items():
-        check_name(expr_info, "Member of %s" % source, key,
+        check_name(info, "Member of %s" % source, key,
                    allow_optional=allow_optional)
+        if c_name(key, False) == 'u' or c_name(key, False).startswith('has_'):
+            raise QAPISemError(info, "Member of %s uses reserved name '%s'"
+                               % (source, key))
         # Todo: allow dictionaries to represent default values of
         # an optional argument.
-        check_type(expr_info, "Member '%s' of %s" % (key, source), arg,
+        check_type(info, "Member '%s' of %s" % (key, source), arg,
                    allow_array=True,
                    allow_metas=['built-in', 'union', 'alternate', 'struct',
                                 'enum'])
 
 
-def check_member_clash(expr_info, base_name, data, source=""):
-    base = find_struct(base_name)
-    assert base
-    base_members = base['data']
-    for key in data.keys():
-        if key.startswith('*'):
-            key = key[1:]
-        if key in base_members or "*" + key in base_members:
-            raise QAPIExprError(expr_info,
-                                "Member name '%s'%s clashes with base '%s'"
-                                % (key, source, base_name))
-    if base.get('base'):
-        check_member_clash(expr_info, base['base'], data, source)
-
-
-def check_command(expr, expr_info):
+def check_command(expr, info):
     name = expr['command']
-
-    check_type(expr_info, "'data' for command '%s'" % name,
-               expr.get('data'), allow_dict=True, allow_optional=True,
-               allow_metas=['struct'])
+    boxed = expr.get('boxed', False)
+
+    args_meta = ['struct']
+    if boxed:
+        args_meta += ['union', 'alternate']
+    check_type(info, "'data' for command '%s'" % name,
+               expr.get('data'), allow_dict=not boxed, allow_optional=True,
+               allow_metas=args_meta)
     returns_meta = ['union', 'struct']
     if name in returns_whitelist:
         returns_meta += ['built-in', 'alternate', 'enum']
-    check_type(expr_info, "'returns' for command '%s'" % name,
+    check_type(info, "'returns' for command '%s'" % name,
                expr.get('returns'), allow_array=True,
                allow_optional=True, allow_metas=returns_meta)
 
 
-def check_event(expr, expr_info):
+def check_event(expr, info):
     global events
     name = expr['event']
+    boxed = expr.get('boxed', False)
 
-    if name.upper() == 'MAX':
-        raise QAPIExprError(expr_info, "Event name 'MAX' cannot be created")
+    meta = ['struct']
+    if boxed:
+        meta += ['union', 'alternate']
     events.append(name)
-    check_type(expr_info, "'data' for event '%s'" % name,
-               expr.get('data'), allow_dict=True, allow_optional=True,
-               allow_metas=['struct'])
+    check_type(info, "'data' for event '%s'" % name,
+               expr.get('data'), allow_dict=not boxed, allow_optional=True,
+               allow_metas=meta)
 
 
-def check_union(expr, expr_info):
+def check_union(expr, info):
     name = expr['union']
     base = expr.get('base')
     discriminator = expr.get('discriminator')
     members = expr['data']
-    values = {'MAX': '(automatic)', 'KIND': '(automatic)'}
 
     # Two types of unions, determined by discriminator.
 
@@ -551,144 +713,118 @@ def check_union(expr, expr_info):
         enum_define = None
         allow_metas = ['built-in', 'union', 'alternate', 'struct', 'enum']
         if base is not None:
-            raise QAPIExprError(expr_info,
-                                "Simple union '%s' must not have a base"
-                                % name)
+            raise QAPISemError(info, "Simple union '%s' must not have a base" %
+                               name)
 
     # Else, it's a flat union.
     else:
-        # The object must have a string member 'base'.
-        check_type(expr_info, "'base' for union '%s'" % name,
-                   base, allow_metas=['struct'])
+        # The object must have a string or dictionary 'base'.
+        check_type(info, "'base' for union '%s'" % name,
+                   base, allow_dict=True, allow_optional=True,
+                   allow_metas=['struct'])
         if not base:
-            raise QAPIExprError(expr_info,
-                                "Flat union '%s' must have a base"
-                                % name)
-        base_fields = find_base_fields(base)
-        assert base_fields
+            raise QAPISemError(info, "Flat union '%s' must have a base"
+                               % name)
+        base_members = find_base_members(base)
+        assert base_members
 
         # The value of member 'discriminator' must name a non-optional
         # member of the base struct.
-        check_name(expr_info, "Discriminator of flat union '%s'" % name,
+        check_name(info, "Discriminator of flat union '%s'" % name,
                    discriminator)
-        discriminator_type = base_fields.get(discriminator)
+        discriminator_type = base_members.get(discriminator)
         if not discriminator_type:
-            raise QAPIExprError(expr_info,
-                                "Discriminator '%s' is not a member of base "
-                                "struct '%s'"
-                                % (discriminator, base))
+            raise QAPISemError(info,
+                               "Discriminator '%s' is not a member of base "
+                               "struct '%s'"
+                               % (discriminator, base))
         enum_define = find_enum(discriminator_type)
         allow_metas = ['struct']
         # Do not allow string discriminator
         if not enum_define:
-            raise QAPIExprError(expr_info,
-                                "Discriminator '%s' must be of enumeration "
-                                "type" % discriminator)
+            raise QAPISemError(info,
+                               "Discriminator '%s' must be of enumeration "
+                               "type" % discriminator)
 
-    # Check every branch
+    # Check every branch; don't allow an empty union
+    if len(members) == 0:
+        raise QAPISemError(info, "Union '%s' cannot have empty 'data'" % name)
     for (key, value) in members.items():
-        check_name(expr_info, "Member of union '%s'" % name, key)
+        check_name(info, "Member of union '%s'" % name, key)
 
-        # Each value must name a known type; furthermore, in flat unions,
-        # branches must be a struct with no overlapping member names
-        check_type(expr_info, "Member '%s' of union '%s'" % (key, name),
+        # Each value must name a known type
+        check_type(info, "Member '%s' of union '%s'" % (key, name),
                    value, allow_array=not base, allow_metas=allow_metas)
-        if base:
-            branch_struct = find_struct(value)
-            assert branch_struct
-            check_member_clash(expr_info, base, branch_struct['data'],
-                               " of branch '%s'" % key)
 
         # If the discriminator names an enum type, then all members
-        # of 'data' must also be members of the enum type, which in turn
-        # must not collide with the discriminator name.
+        # of 'data' must also be members of the enum type.
         if enum_define:
             if key not in enum_define['enum_values']:
-                raise QAPIExprError(expr_info,
-                                    "Discriminator value '%s' is not found in "
-                                    "enum '%s'" %
-                                    (key, enum_define["enum_name"]))
-            if discriminator in enum_define['enum_values']:
-                raise QAPIExprError(expr_info,
-                                    "Discriminator name '%s' collides with "
-                                    "enum value in '%s'" %
-                                    (discriminator, enum_define["enum_name"]))
-
-        # Otherwise, check for conflicts in the generated enum
-        else:
-            c_key = camel_to_upper(key)
-            if c_key in values:
-                raise QAPIExprError(expr_info,
-                                    "Union '%s' member '%s' clashes with '%s'"
-                                    % (name, key, values[c_key]))
-            values[c_key] = key
+                raise QAPISemError(info,
+                                   "Discriminator value '%s' is not found in "
+                                   "enum '%s'"
+                                   % (key, enum_define["enum_name"]))
 
+    # If discriminator is user-defined, ensure all values are covered
+    if enum_define:
+        for value in enum_define['enum_values']:
+            if value not in members.keys():
+                raise QAPISemError(info, "Union '%s' data missing '%s' branch"
+                                   % (name, value))
 
-def check_alternate(expr, expr_info):
+
+def check_alternate(expr, info):
     name = expr['alternate']
     members = expr['data']
-    values = {'MAX': '(automatic)'}
     types_seen = {}
 
-    # Check every branch
+    # Check every branch; require at least two branches
+    if len(members) < 2:
+        raise QAPISemError(info,
+                           "Alternate '%s' should have at least two branches "
+                           "in 'data'" % name)
     for (key, value) in members.items():
-        check_name(expr_info, "Member of alternate '%s'" % name, key)
-
-        # Check for conflicts in the generated enum
-        c_key = camel_to_upper(key)
-        if c_key in values:
-            raise QAPIExprError(expr_info,
-                                "Alternate '%s' member '%s' clashes with '%s'"
-                                % (name, key, values[c_key]))
-        values[c_key] = key
+        check_name(info, "Member of alternate '%s'" % name, key)
 
         # Ensure alternates have no type conflicts.
-        check_type(expr_info, "Member '%s' of alternate '%s'" % (key, name),
+        check_type(info, "Member '%s' of alternate '%s'" % (key, name),
                    value,
                    allow_metas=['built-in', 'union', 'struct', 'enum'])
         qtype = find_alternate_member_qtype(value)
-        assert qtype
+        if not qtype:
+            raise QAPISemError(info, "Alternate '%s' member '%s' cannot use "
+                               "type '%s'" % (name, key, value))
         if qtype in types_seen:
-            raise QAPIExprError(expr_info,
-                                "Alternate '%s' member '%s' can't "
-                                "be distinguished from member '%s'"
-                                % (name, key, types_seen[qtype]))
+            raise QAPISemError(info, "Alternate '%s' member '%s' can't "
+                               "be distinguished from member '%s'"
+                               % (name, key, types_seen[qtype]))
         types_seen[qtype] = key
 
 
-def check_enum(expr, expr_info):
+def check_enum(expr, info):
     name = expr['enum']
     members = expr.get('data')
     prefix = expr.get('prefix')
-    values = {'MAX': '(automatic)'}
 
     if not isinstance(members, list):
-        raise QAPIExprError(expr_info,
-                            "Enum '%s' requires an array for 'data'" % name)
+        raise QAPISemError(info,
+                           "Enum '%s' requires an array for 'data'" % name)
     if prefix is not None and not isinstance(prefix, str):
-        raise QAPIExprError(expr_info,
-                            "Enum '%s' requires a string for 'prefix'" % name)
+        raise QAPISemError(info,
+                           "Enum '%s' requires a string for 'prefix'" % name)
     for member in members:
-        check_name(expr_info, "Member of enum '%s'" % name, member,
+        check_name(info, "Member of enum '%s'" % name, member,
                    enum_member=True)
-        key = camel_to_upper(member)
-        if key in values:
-            raise QAPIExprError(expr_info,
-                                "Enum '%s' member '%s' clashes with '%s'"
-                                % (name, member, values[key]))
-        values[key] = member
 
 
-def check_struct(expr, expr_info):
+def check_struct(expr, info):
     name = expr['struct']
     members = expr['data']
 
-    check_type(expr_info, "'data' for struct '%s'" % name, members,
+    check_type(info, "'data' for struct '%s'" % name, members,
                allow_dict=True, allow_optional=True)
-    check_type(expr_info, "'base' for struct '%s'" % name, expr.get('base'),
+    check_type(info, "'base' for struct '%s'" % name, expr.get('base'),
                allow_metas=['struct'])
-    if expr.get('base'):
-        check_member_clash(expr_info, expr['base'], expr['data'])
 
 
 def check_keys(expr_elem, meta, required, optional=[]):
@@ -696,23 +832,24 @@ def check_keys(expr_elem, meta, required, optional=[]):
     info = expr_elem['info']
     name = expr[meta]
     if not isinstance(name, str):
-        raise QAPIExprError(info,
-                            "'%s' key must have a string value" % meta)
+        raise QAPISemError(info, "'%s' key must have a string value" % meta)
     required = required + [meta]
     for (key, value) in expr.items():
         if key not in required and key not in optional:
-            raise QAPIExprError(info,
-                                "Unknown key '%s' in %s '%s'"
-                                % (key, meta, name))
+            raise QAPISemError(info, "Unknown key '%s' in %s '%s'"
+                               % (key, meta, name))
         if (key == 'gen' or key == 'success-response') and value is not False:
-            raise QAPIExprError(info,
-                                "'%s' of %s '%s' should only use false value"
-                                % (key, meta, name))
+            raise QAPISemError(info,
+                               "'%s' of %s '%s' should only use false value"
+                               % (key, meta, name))
+        if key == 'boxed' and value is not True:
+            raise QAPISemError(info,
+                               "'%s' of %s '%s' should only use true value"
+                               % (key, meta, name))
     for key in required:
         if key not in expr:
-            raise QAPIExprError(info,
-                                "Key '%s' is missing from %s '%s'"
-                                % (key, meta, name))
+            raise QAPISemError(info, "Key '%s' is missing from %s '%s'"
+                               % (key, meta, name))
 
 
 def check_exprs(exprs):
@@ -724,6 +861,11 @@ def check_exprs(exprs):
     for expr_elem in exprs:
         expr = expr_elem['expr']
         info = expr_elem['info']
+
+        if 'doc' not in expr_elem:
+            raise QAPISemError(info,
+                               "Expression missing documentation comment")
+
         if 'enum' in expr:
             check_keys(expr_elem, 'enum', ['data'], ['prefix'])
             add_enum(expr['enum'], info, expr['data'])
@@ -739,14 +881,14 @@ def check_exprs(exprs):
             add_struct(expr, info)
         elif 'command' in expr:
             check_keys(expr_elem, 'command', [],
-                       ['data', 'returns', 'gen', 'success-response'])
+                       ['data', 'returns', 'gen', 'success-response', 'boxed'])
             add_name(expr['command'], info, 'command')
         elif 'event' in expr:
-            check_keys(expr_elem, 'event', [], ['data'])
+            check_keys(expr_elem, 'event', [], ['data', 'boxed'])
             add_name(expr['event'], info, 'event')
         else:
-            raise QAPIExprError(expr_elem['info'],
-                                "Expression is missing metatype")
+            raise QAPISemError(expr_elem['info'],
+                               "Expression is missing metatype")
 
     # Try again for hidden UnionKind enum
     for expr_elem in exprs:
@@ -782,6 +924,88 @@ def check_exprs(exprs):
     return exprs
 
 
+def check_freeform_doc(doc):
+    if doc.symbol:
+        raise QAPISemError(doc.info,
+                           "Documention for '%s' is not followed"
+                           " by the definition" % doc.symbol)
+
+    body = str(doc.body)
+    if re.search(r'@\S+:', body, re.MULTILINE):
+        raise QAPISemError(doc.info,
+                           "Free-form documentation block must not contain"
+                           " @NAME: sections")
+
+
+def check_definition_doc(doc, expr, info):
+    for i in ('enum', 'union', 'alternate', 'struct', 'command', 'event'):
+        if i in expr:
+            meta = i
+            break
+
+    name = expr[meta]
+    if doc.symbol != name:
+        raise QAPISemError(info, "Definition of '%s' follows documentation"
+                           " for '%s'" % (name, doc.symbol))
+    if doc.has_section('Returns') and 'command' not in expr:
+        raise QAPISemError(info, "'Returns:' is only valid for commands")
+
+    if meta == 'union':
+        args = expr.get('base', [])
+    else:
+        args = expr.get('data', [])
+    if isinstance(args, str):
+        return
+    if isinstance(args, dict):
+        args = args.keys()
+    assert isinstance(args, list)
+
+    if (meta == 'alternate'
+            or (meta == 'union' and not expr.get('discriminator'))):
+        args.append('type')
+
+    for arg in args:
+        if arg[0] == '*':
+            opt = True
+            desc = doc.args.get(arg[1:])
+        else:
+            opt = False
+            desc = doc.args.get(arg)
+        if not desc:
+            continue
+        desc_opt = "#optional" in str(desc)
+        if desc_opt and not opt:
+            raise QAPISemError(info, "Description has #optional, "
+                               "but the declaration doesn't")
+        if not desc_opt and opt:
+            # silently fix the doc
+            # TODO either fix the schema and make this an error,
+            # or drop #optional entirely
+            desc.append("#optional")
+
+    doc_args = set(doc.args.keys())
+    args = set([name.strip('*') for name in args])
+    if not doc_args.issubset(args):
+        raise QAPISemError(info, "The following documented members are not in "
+                           "the declaration: %s" % ", ".join(doc_args - args))
+
+
+def check_docs(docs):
+    for doc in docs:
+        for section in doc.args.values() + doc.sections:
+            content = str(section)
+            if not content or content.isspace():
+                raise QAPISemError(doc.info,
+                                   "Empty doc section '%s'" % section.name)
+
+        if not doc.expr:
+            check_freeform_doc(doc)
+        else:
+            check_definition_doc(doc, doc.expr, doc.info)
+
+    return docs
+
+
 #
 # Schema compiler frontend
 #
@@ -840,19 +1064,26 @@ class QAPISchemaVisitor(object):
         pass
 
     def visit_command(self, name, info, arg_type, ret_type,
-                      gen, success_response):
+                      gen, success_response, boxed):
         pass
 
-    def visit_event(self, name, info, arg_type):
+    def visit_event(self, name, info, arg_type, boxed):
         pass
 
 
 class QAPISchemaType(QAPISchemaEntity):
-    def c_type(self, is_param=False):
-        return c_name(self.name) + pointer_suffix
+    # Return the C type for common use.
+    # For the types we commonly box, this is a pointer type.
+    def c_type(self):
+        pass
 
-    def c_null(self):
-        return 'NULL'
+    # Return the C type to be used in a parameter list.
+    def c_param_type(self):
+        return self.c_type()
+
+    # Return the C type to be used where we suppress boxing.
+    def c_unboxed_type(self):
+        return self.c_type()
 
     def json_type(self):
         pass
@@ -869,25 +1100,24 @@ class QAPISchemaType(QAPISchemaEntity):
 
 
 class QAPISchemaBuiltinType(QAPISchemaType):
-    def __init__(self, name, json_type, c_type, c_null):
+    def __init__(self, name, json_type, c_type):
         QAPISchemaType.__init__(self, name, None)
         assert not c_type or isinstance(c_type, str)
         assert json_type in ('string', 'number', 'int', 'boolean', 'null',
                              'value')
         self._json_type_name = json_type
         self._c_type_name = c_type
-        self._c_null_val = c_null
 
     def c_name(self):
         return self.name
 
-    def c_type(self, is_param=False):
-        if is_param and self.name == 'str':
-            return 'const ' + self._c_type_name
+    def c_type(self):
         return self._c_type_name
 
-    def c_null(self):
-        return self._c_null_val
+    def c_param_type(self):
+        if self.name == 'str':
+            return 'const ' + self._c_type_name
+        return self._c_type_name
 
     def json_type(self):
         return self._json_type_name
@@ -900,31 +1130,33 @@ class QAPISchemaEnumType(QAPISchemaType):
     def __init__(self, name, info, values, prefix):
         QAPISchemaType.__init__(self, name, info)
         for v in values:
-            assert isinstance(v, str)
+            assert isinstance(v, QAPISchemaMember)
+            v.set_owner(name)
         assert prefix is None or isinstance(prefix, str)
         self.values = values
         self.prefix = prefix
 
     def check(self, schema):
-        assert len(set(self.values)) == len(self.values)
+        seen = {}
+        for v in self.values:
+            v.check_clash(self.info, seen)
 
     def is_implicit(self):
         # See QAPISchema._make_implicit_enum_type()
-        return self.name[-4:] == 'Kind'
+        return self.name.endswith('Kind')
 
-    def c_type(self, is_param=False):
+    def c_type(self):
         return c_name(self.name)
 
-    def c_null(self):
-        return c_enum_const(self.name, (self.values + ['MAX'])[0],
-                            self.prefix)
+    def member_names(self):
+        return [v.name for v in self.values]
 
     def json_type(self):
         return 'string'
 
     def visit(self, visitor):
         visitor.visit_enum_type(self.name, self.info,
-                                self.values, self.prefix)
+                                self.member_names(), self.prefix)
 
 
 class QAPISchemaArrayType(QAPISchemaType):
@@ -941,6 +1173,9 @@ class QAPISchemaArrayType(QAPISchemaType):
     def is_implicit(self):
         return True
 
+    def c_type(self):
+        return c_name(self.name) + pointer_suffix
+
     def json_type(self):
         return 'array'
 
@@ -950,12 +1185,17 @@ class QAPISchemaArrayType(QAPISchemaType):
 
 class QAPISchemaObjectType(QAPISchemaType):
     def __init__(self, name, info, base, local_members, variants):
+        # struct has local_members, optional base, and no variants
+        # flat union has base, variants, and no local_members
+        # simple union has local_members, variants, and no base
         QAPISchemaType.__init__(self, name, info)
         assert base is None or isinstance(base, str)
         for m in local_members:
             assert isinstance(m, QAPISchemaObjectTypeMember)
-        assert (variants is None or
-                isinstance(variants, QAPISchemaObjectTypeVariants))
+            m.set_owner(name)
+        if variants is not None:
+            assert isinstance(variants, QAPISchemaObjectTypeVariants)
+            variants.set_owner(name)
         self._base_name = base
         self.base = None
         self.local_members = local_members
@@ -963,39 +1203,54 @@ class QAPISchemaObjectType(QAPISchemaType):
         self.members = None
 
     def check(self, schema):
-        assert self.members is not False        # not running in cycles
+        if self.members is False:               # check for cycles
+            raise QAPISemError(self.info,
+                               "Object %s contains itself" % self.name)
         if self.members:
             return
         self.members = False                    # mark as being checked
+        seen = OrderedDict()
         if self._base_name:
             self.base = schema.lookup_type(self._base_name)
             assert isinstance(self.base, QAPISchemaObjectType)
-            assert not self.base.variants       # not implemented
             self.base.check(schema)
-            members = list(self.base.members)
-        else:
-            members = []
-        seen = {}
-        for m in members:
-            assert c_name(m.name) not in seen
-            seen[m.name] = m
+            self.base.check_clash(schema, self.info, seen)
         for m in self.local_members:
-            m.check(schema, members, seen)
+            m.check(schema)
+            m.check_clash(self.info, seen)
+        self.members = seen.values()
         if self.variants:
-            self.variants.check(schema, members, seen)
-        self.members = members
+            self.variants.check(schema, seen)
+            assert self.variants.tag_member in self.members
+            self.variants.check_clash(schema, self.info, seen)
+
+    # Check that the members of this type do not cause duplicate JSON members,
+    # and update seen to track the members seen so far. Report any errors
+    # on behalf of info, which is not necessarily self.info
+    def check_clash(self, schema, info, seen):
+        assert not self.variants       # not implemented
+        for m in self.members:
+            m.check_clash(info, seen)
 
     def is_implicit(self):
-        # See QAPISchema._make_implicit_object_type()
-        return self.name[0] == ':'
+        # See QAPISchema._make_implicit_object_type(), as well as
+        # _def_predefineds()
+        return self.name.startswith('q_')
+
+    def is_empty(self):
+        assert self.members is not None
+        return not self.members and not self.variants
 
     def c_name(self):
-        assert not self.is_implicit()
+        assert self.name != 'q_empty'
         return QAPISchemaType.c_name(self)
 
-    def c_type(self, is_param=False):
+    def c_type(self):
         assert not self.is_implicit()
-        return QAPISchemaType.c_type(self)
+        return c_name(self.name) + pointer_suffix
+
+    def c_unboxed_type(self):
+        return c_name(self.name)
 
     def json_type(self):
         return 'object'
@@ -1007,22 +1262,64 @@ class QAPISchemaObjectType(QAPISchemaType):
                                        self.members, self.variants)
 
 
-class QAPISchemaObjectTypeMember(object):
-    def __init__(self, name, typ, optional):
+class QAPISchemaMember(object):
+    role = 'member'
+
+    def __init__(self, name):
         assert isinstance(name, str)
+        self.name = name
+        self.owner = None
+
+    def set_owner(self, name):
+        assert not self.owner
+        self.owner = name
+
+    def check_clash(self, info, seen):
+        cname = c_name(self.name)
+        if cname.lower() != cname and self.owner not in case_whitelist:
+            raise QAPISemError(info,
+                               "%s should not use uppercase" % self.describe())
+        if cname in seen:
+            raise QAPISemError(info, "%s collides with %s" %
+                               (self.describe(), seen[cname].describe()))
+        seen[cname] = self
+
+    def _pretty_owner(self):
+        owner = self.owner
+        if owner.startswith('q_obj_'):
+            # See QAPISchema._make_implicit_object_type() - reverse the
+            # mapping there to create a nice human-readable description
+            owner = owner[6:]
+            if owner.endswith('-arg'):
+                return '(parameter of %s)' % owner[:-4]
+            elif owner.endswith('-base'):
+                return '(base of %s)' % owner[:-5]
+            else:
+                assert owner.endswith('-wrapper')
+                # Unreachable and not implemented
+                assert False
+        if owner.endswith('Kind'):
+            # See QAPISchema._make_implicit_enum_type()
+            return '(branch of %s)' % owner[:-4]
+        return '(%s of %s)' % (self.role, owner)
+
+    def describe(self):
+        return "'%s' %s" % (self.name, self._pretty_owner())
+
+
+class QAPISchemaObjectTypeMember(QAPISchemaMember):
+    def __init__(self, name, typ, optional):
+        QAPISchemaMember.__init__(self, name)
         assert isinstance(typ, str)
         assert isinstance(optional, bool)
-        self.name = name
         self._type_name = typ
         self.type = None
         self.optional = optional
 
-    def check(self, schema, all_members, seen):
-        assert self.name not in seen
+    def check(self, schema):
+        assert self.owner
         self.type = schema.lookup_type(self._type_name)
         assert self.type
-        all_members.append(self)
-        seen[self.name] = self
 
 
 class QAPISchemaObjectTypeVariants(object):
@@ -1034,51 +1331,68 @@ class QAPISchemaObjectTypeVariants(object):
         assert bool(tag_member) != bool(tag_name)
         assert (isinstance(tag_name, str) or
                 isinstance(tag_member, QAPISchemaObjectTypeMember))
+        assert len(variants) > 0
         for v in variants:
             assert isinstance(v, QAPISchemaObjectTypeVariant)
-        self.tag_name = tag_name
+        self._tag_name = tag_name
         self.tag_member = tag_member
         self.variants = variants
 
-    def check(self, schema, members, seen):
-        if self.tag_name:
-            self.tag_member = seen[self.tag_name]
-        else:
-            self.tag_member.check(schema, members, seen)
+    def set_owner(self, name):
+        for v in self.variants:
+            v.set_owner(name)
+
+    def check(self, schema, seen):
+        if not self.tag_member:    # flat union
+            self.tag_member = seen[c_name(self._tag_name)]
+            assert self._tag_name == self.tag_member.name
         assert isinstance(self.tag_member.type, QAPISchemaEnumType)
         for v in self.variants:
-            vseen = dict(seen)
-            v.check(schema, self.tag_member.type, vseen)
+            v.check(schema)
+            # Union names must match enum values; alternate names are
+            # checked separately. Use 'seen' to tell the two apart.
+            if seen:
+                assert v.name in self.tag_member.type.member_names()
+                assert isinstance(v.type, QAPISchemaObjectType)
+                v.type.check(schema)
+
+    def check_clash(self, schema, info, seen):
+        for v in self.variants:
+            # Reset seen map for each variant, since qapi names from one
+            # branch do not affect another branch
+            assert isinstance(v.type, QAPISchemaObjectType)
+            v.type.check_clash(schema, info, dict(seen))
 
 
 class QAPISchemaObjectTypeVariant(QAPISchemaObjectTypeMember):
+    role = 'branch'
+
     def __init__(self, name, typ):
         QAPISchemaObjectTypeMember.__init__(self, name, typ, False)
 
-    def check(self, schema, tag_type, seen):
-        QAPISchemaObjectTypeMember.check(self, schema, [], seen)
-        assert self.name in tag_type.values
-
-    # This function exists to support ugly simple union special cases
-    # TODO get rid of them, and drop the function
-    def simple_union_type(self):
-        if (self.type.is_implicit() and
-                isinstance(self.type, QAPISchemaObjectType)):
-            assert len(self.type.members) == 1
-            assert not self.type.variants
-            return self.type.members[0].type
-        return None
-
 
 class QAPISchemaAlternateType(QAPISchemaType):
     def __init__(self, name, info, variants):
         QAPISchemaType.__init__(self, name, info)
         assert isinstance(variants, QAPISchemaObjectTypeVariants)
-        assert not variants.tag_name
+        assert variants.tag_member
+        variants.set_owner(name)
+        variants.tag_member.set_owner(self.name)
         self.variants = variants
 
     def check(self, schema):
-        self.variants.check(schema, [], {})
+        self.variants.tag_member.check(schema)
+        # Not calling self.variants.check_clash(), because there's nothing
+        # to clash with
+        self.variants.check(schema, {})
+        # Alternate branch names have no relation to the tag enum values;
+        # so we have to check for potential name collisions ourselves.
+        seen = {}
+        for v in self.variants.variants:
+            v.check_clash(self.info, seen)
+
+    def c_type(self):
+        return c_name(self.name) + pointer_suffix
 
     def json_type(self):
         return 'value'
@@ -1086,9 +1400,13 @@ class QAPISchemaAlternateType(QAPISchemaType):
     def visit(self, visitor):
         visitor.visit_alternate_type(self.name, self.info, self.variants)
 
+    def is_empty(self):
+        return False
+
 
 class QAPISchemaCommand(QAPISchemaEntity):
-    def __init__(self, name, info, arg_type, ret_type, gen, success_response):
+    def __init__(self, name, info, arg_type, ret_type, gen, success_response,
+                 boxed):
         QAPISchemaEntity.__init__(self, name, info)
         assert not arg_type or isinstance(arg_type, str)
         assert not ret_type or isinstance(ret_type, str)
@@ -1098,12 +1416,23 @@ class QAPISchemaCommand(QAPISchemaEntity):
         self.ret_type = None
         self.gen = gen
         self.success_response = success_response
+        self.boxed = boxed
 
     def check(self, schema):
         if self._arg_type_name:
             self.arg_type = schema.lookup_type(self._arg_type_name)
-            assert isinstance(self.arg_type, QAPISchemaObjectType)
-            assert not self.arg_type.variants   # not implemented
+            assert (isinstance(self.arg_type, QAPISchemaObjectType) or
+                    isinstance(self.arg_type, QAPISchemaAlternateType))
+            self.arg_type.check(schema)
+            if self.boxed:
+                if self.arg_type.is_empty():
+                    raise QAPISemError(self.info,
+                                       "Cannot use 'boxed' with empty type")
+            else:
+                assert not isinstance(self.arg_type, QAPISchemaAlternateType)
+                assert not self.arg_type.variants
+        elif self.boxed:
+            raise QAPISemError(self.info, "Use of 'boxed' requires 'data'")
         if self._ret_type_name:
             self.ret_type = schema.lookup_type(self._ret_type_name)
             assert isinstance(self.ret_type, QAPISchemaType)
@@ -1111,37 +1440,50 @@ class QAPISchemaCommand(QAPISchemaEntity):
     def visit(self, visitor):
         visitor.visit_command(self.name, self.info,
                               self.arg_type, self.ret_type,
-                              self.gen, self.success_response)
+                              self.gen, self.success_response, self.boxed)
 
 
 class QAPISchemaEvent(QAPISchemaEntity):
-    def __init__(self, name, info, arg_type):
+    def __init__(self, name, info, arg_type, boxed):
         QAPISchemaEntity.__init__(self, name, info)
         assert not arg_type or isinstance(arg_type, str)
         self._arg_type_name = arg_type
         self.arg_type = None
+        self.boxed = boxed
 
     def check(self, schema):
         if self._arg_type_name:
             self.arg_type = schema.lookup_type(self._arg_type_name)
-            assert isinstance(self.arg_type, QAPISchemaObjectType)
-            assert not self.arg_type.variants   # not implemented
+            assert (isinstance(self.arg_type, QAPISchemaObjectType) or
+                    isinstance(self.arg_type, QAPISchemaAlternateType))
+            self.arg_type.check(schema)
+            if self.boxed:
+                if self.arg_type.is_empty():
+                    raise QAPISemError(self.info,
+                                       "Cannot use 'boxed' with empty type")
+            else:
+                assert not isinstance(self.arg_type, QAPISchemaAlternateType)
+                assert not self.arg_type.variants
+        elif self.boxed:
+            raise QAPISemError(self.info, "Use of 'boxed' requires 'data'")
 
     def visit(self, visitor):
-        visitor.visit_event(self.name, self.info, self.arg_type)
+        visitor.visit_event(self.name, self.info, self.arg_type, self.boxed)
 
 
 class QAPISchema(object):
     def __init__(self, fname):
         try:
-            self.exprs = check_exprs(QAPISchemaParser(open(fname, "r")).exprs)
+            parser = QAPISchemaParser(open(fname, "r"))
+            self.exprs = check_exprs(parser.exprs)
+            self.docs = check_docs(parser.docs)
             self._entity_dict = {}
             self._predefining = True
             self._def_predefineds()
             self._predefining = False
             self._def_exprs()
             self.check()
-        except (QAPISchemaError, QAPIExprError), err:
+        except QAPIError as err:
             print >>sys.stderr, err
             exit(1)
 
@@ -1160,9 +1502,8 @@ class QAPISchema(object):
     def lookup_type(self, name):
         return self.lookup_entity(name, QAPISchemaType)
 
-    def _def_builtin_type(self, name, json_type, c_type, c_null):
-        self._def_entity(QAPISchemaBuiltinType(name, json_type,
-                                               c_type, c_null))
+    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
@@ -1171,34 +1512,42 @@ class QAPISchema(object):
         self._make_array_type(name, None)
 
     def _def_predefineds(self):
-        for t in [('str',    'string',  'char' + pointer_suffix, 'NULL'),
-                  ('number', 'number',  'double',   '0'),
-                  ('int',    'int',     'int64_t',  '0'),
-                  ('int8',   'int',     'int8_t',   '0'),
-                  ('int16',  'int',     'int16_t',  '0'),
-                  ('int32',  'int',     'int32_t',  '0'),
-                  ('int64',  'int',     'int64_t',  '0'),
-                  ('uint8',  'int',     'uint8_t',  '0'),
-                  ('uint16', 'int',     'uint16_t', '0'),
-                  ('uint32', 'int',     'uint32_t', '0'),
-                  ('uint64', 'int',     'uint64_t', '0'),
-                  ('size',   'int',     'uint64_t', '0'),
-                  ('bool',   'boolean', 'bool',     'false'),
-                  ('any',    'value',   'QObject' + pointer_suffix, 'NULL')]:
+        for t in [('str',    'string',  'char' + pointer_suffix),
+                  ('number', 'number',  'double'),
+                  ('int',    'int',     'int64_t'),
+                  ('int8',   'int',     'int8_t'),
+                  ('int16',  'int',     'int16_t'),
+                  ('int32',  'int',     'int32_t'),
+                  ('int64',  'int',     'int64_t'),
+                  ('uint8',  'int',     'uint8_t'),
+                  ('uint16', 'int',     'uint16_t'),
+                  ('uint32', 'int',     'uint32_t'),
+                  ('uint64', 'int',     'uint64_t'),
+                  ('size',   'int',     'uint64_t'),
+                  ('bool',   'boolean', 'bool'),
+                  ('any',    'value',   'QObject' + pointer_suffix)]:
             self._def_builtin_type(*t)
-        self.the_empty_object_type = QAPISchemaObjectType(':empty', None, None,
-                                                          [], None)
+        self.the_empty_object_type = QAPISchemaObjectType('q_empty', None,
+                                                          None, [], None)
         self._def_entity(self.the_empty_object_type)
+        qtype_values = self._make_enum_members(['none', 'qnull', 'qint',
+                                                'qstring', 'qdict', 'qlist',
+                                                'qfloat', 'qbool'])
+        self._def_entity(QAPISchemaEnumType('QType', None, qtype_values,
+                                            'QTYPE'))
+
+    def _make_enum_members(self, values):
+        return [QAPISchemaMember(v) for v in values]
 
     def _make_implicit_enum_type(self, name, info, values):
+        # See also QAPISchemaObjectTypeMember._pretty_owner()
         name = name + 'Kind'   # Use namespace reserved by add_name()
-        self._def_entity(QAPISchemaEnumType(name, info, values, None))
+        self._def_entity(QAPISchemaEnumType(
+            name, info, self._make_enum_members(values), None))
         return name
 
     def _make_array_type(self, element_type, info):
-        # TODO fooList namespace is not reserved; user can create collisions,
-        # or abuse our type system with ['fooList'] for 2D array
-        name = element_type + 'List'
+        name = element_type + 'List'   # Use namespace reserved by add_name()
         if not self.lookup_type(name):
             self._def_entity(QAPISchemaArrayType(name, info, element_type))
         return name
@@ -1206,7 +1555,8 @@ class QAPISchema(object):
     def _make_implicit_object_type(self, name, info, role, members):
         if not members:
             return None
-        name = ':obj-%s-%s' % (name, role)
+        # See also QAPISchemaObjectTypeMember._pretty_owner()
+        name = 'q_obj_%s-%s' % (name, role)
         if not self.lookup_entity(name, QAPISchemaObjectType):
             self._def_entity(QAPISchemaObjectType(name, info, None,
                                                   members, None))
@@ -1216,7 +1566,8 @@ class QAPISchema(object):
         name = expr['enum']
         data = expr['data']
         prefix = expr.get('prefix')
-        self._def_entity(QAPISchemaEnumType(name, info, data, prefix))
+        self._def_entity(QAPISchemaEnumType(
+            name, info, self._make_enum_members(data), prefix))
 
     def _make_member(self, name, typ, info):
         optional = False
@@ -1251,27 +1602,28 @@ class QAPISchema(object):
             typ, info, 'wrapper', [self._make_member('data', typ, info)])
         return QAPISchemaObjectTypeVariant(case, typ)
 
-    def _make_implicit_tag(self, type_name, info, variants):
-        typ = self._make_implicit_enum_type(type_name, info,
-                                            [v.name for v in variants])
-        return QAPISchemaObjectTypeMember('type', typ, False)
-
     def _def_union_type(self, expr, info):
         name = expr['union']
         data = expr['data']
         base = expr.get('base')
         tag_name = expr.get('discriminator')
         tag_member = None
+        if isinstance(base, dict):
+            base = (self._make_implicit_object_type(
+                    name, info, 'base', self._make_members(base, info)))
         if tag_name:
             variants = [self._make_variant(key, value)
                         for (key, value) in data.iteritems()]
+            members = []
         else:
             variants = [self._make_simple_variant(key, value, info)
                         for (key, value) in data.iteritems()]
-            tag_member = self._make_implicit_tag(name, info, variants)
+            typ = self._make_implicit_enum_type(name, info,
+                                                [v.name for v in variants])
+            tag_member = QAPISchemaObjectTypeMember('type', typ, False)
+            members = [tag_member]
         self._def_entity(
-            QAPISchemaObjectType(name, info, base,
-                                 self._make_members(OrderedDict(), info),
+            QAPISchemaObjectType(name, info, base, members,
                                  QAPISchemaObjectTypeVariants(tag_name,
                                                               tag_member,
                                                               variants)))
@@ -1281,7 +1633,7 @@ class QAPISchema(object):
         data = expr['data']
         variants = [self._make_variant(key, value)
                     for (key, value) in data.iteritems()]
-        tag_member = self._make_implicit_tag(name, info, variants)
+        tag_member = QAPISchemaObjectTypeMember('type', 'QType', False)
         self._def_entity(
             QAPISchemaAlternateType(name, info,
                                     QAPISchemaObjectTypeVariants(None,
@@ -1294,6 +1646,7 @@ class QAPISchema(object):
         rets = expr.get('returns')
         gen = expr.get('gen', True)
         success_response = expr.get('success-response', True)
+        boxed = expr.get('boxed', False)
         if isinstance(data, OrderedDict):
             data = self._make_implicit_object_type(
                 name, info, 'arg', self._make_members(data, info))
@@ -1301,15 +1654,16 @@ class QAPISchema(object):
             assert len(rets) == 1
             rets = self._make_array_type(rets[0], info)
         self._def_entity(QAPISchemaCommand(name, info, data, rets, gen,
-                                           success_response))
+                                           success_response, boxed))
 
     def _def_event(self, expr, info):
         name = expr['event']
         data = expr.get('data')
+        boxed = expr.get('boxed', False)
         if isinstance(data, OrderedDict):
             data = self._make_implicit_object_type(
                 name, info, 'arg', self._make_members(data, info))
-        self._def_entity(QAPISchemaEvent(name, info, data))
+        self._def_entity(QAPISchemaEvent(name, info, data, boxed))
 
     def _def_exprs(self):
         for expr_elem in self.exprs:
@@ -1385,7 +1739,7 @@ def camel_to_upper(value):
 def c_enum_const(type_name, const_name, prefix=None):
     if prefix is not None:
         type_name = prefix
-    return camel_to_upper(type_name + '_' + const_name)
+    return camel_to_upper(type_name) + '_' + c_name(const_name, False).upper()
 
 c_name_trans = string.maketrans('.-', '__')
 
@@ -1426,11 +1780,12 @@ def c_name(name, protect=True):
                      'and', 'and_eq', 'bitand', 'bitor', 'compl', 'not',
                      'not_eq', 'or', 'or_eq', 'xor', 'xor_eq'])
     # namespace pollution:
-    polluted_words = set(['unix', 'errno'])
+    polluted_words = set(['unix', 'errno', 'mips', 'sparc'])
+    name = name.translate(c_name_trans)
     if protect and (name in c89_words | c99_words | c11_words | gcc_words
                     | cpp_words | polluted_words):
         return "q_" + name
-    return name.translate(c_name_trans)
+    return name
 
 eatspace = '\033EATSPACE.'
 pointer_suffix = ' *' + eatspace
@@ -1510,7 +1865,7 @@ const char *const %(c_name)s_lookup[] = {
 ''',
                      index=index, value=value)
 
-    max_index = c_enum_const(name, 'MAX', prefix)
+    max_index = c_enum_const(name, '_MAX', prefix)
     ret += mcgen('''
     [%(max_index)s] = NULL,
 };
@@ -1521,7 +1876,7 @@ const char *const %(c_name)s_lookup[] = {
 
 def gen_enum(name, values, prefix=None):
     # append automatically generated _MAX value
-    enum_values = values + ['MAX']
+    enum_values = values + ['_MAX']
 
     ret = mcgen('''
 
@@ -1551,77 +1906,29 @@ extern const char *const %(c_name)s_lookup[];
     return ret
 
 
-def gen_params(arg_type, extra):
+def gen_params(arg_type, boxed, extra):
     if not arg_type:
+        assert not boxed
         return extra
-    assert not arg_type.variants
     ret = ''
     sep = ''
-    for memb in arg_type.members:
-        ret += sep
+    if boxed:
+        ret += '%s arg' % arg_type.c_param_type()
         sep = ', '
-        if memb.optional:
-            ret += 'bool has_%s, ' % c_name(memb.name)
-        ret += '%s %s' % (memb.type.c_type(is_param=True), c_name(memb.name))
+    else:
+        assert not arg_type.variants
+        for memb in arg_type.members:
+            ret += sep
+            sep = ', '
+            if memb.optional:
+                ret += 'bool has_%s, ' % c_name(memb.name)
+            ret += '%s %s' % (memb.type.c_param_type(),
+                              c_name(memb.name))
     if extra:
         ret += sep + extra
     return ret
 
 
-def gen_err_check(label='out', skiperr=False):
-    if skiperr:
-        return ''
-    return mcgen('''
-    if (err) {
-        goto %(label)s;
-    }
-''',
-                 label=label)
-
-
-def gen_visit_fields(members, prefix='', need_cast=False, skiperr=False):
-    ret = ''
-    if skiperr:
-        errparg = 'NULL'
-    else:
-        errparg = '&err'
-
-    for memb in members:
-        if memb.optional:
-            ret += mcgen('''
-    visit_optional(v, &%(prefix)shas_%(c_name)s, "%(name)s", %(errp)s);
-''',
-                         prefix=prefix, c_name=c_name(memb.name),
-                         name=memb.name, errp=errparg)
-            ret += gen_err_check(skiperr=skiperr)
-            ret += mcgen('''
-    if (%(prefix)shas_%(c_name)s) {
-''',
-                         prefix=prefix, c_name=c_name(memb.name))
-            push_indent()
-
-        # Ugly: sometimes we need to cast away const
-        if need_cast and memb.type.name == 'str':
-            cast = '(char **)'
-        else:
-            cast = ''
-
-        ret += mcgen('''
-    visit_type_%(c_type)s(v, %(cast)s&%(prefix)s%(c_name)s, "%(name)s", %(errp)s);
-''',
-                     c_type=memb.type.c_name(), prefix=prefix, cast=cast,
-                     c_name=c_name(memb.name), name=memb.name,
-                     errp=errparg)
-        ret += gen_err_check(skiperr=skiperr)
-
-        if memb.optional:
-            pop_indent()
-            ret += mcgen('''
-    }
-''')
-    return ret
-
-
 #
 # Common command line parsing
 #
@@ -1634,7 +1941,7 @@ def parse_command_line(extra_options="", extra_long_options=[]):
                                        "chp:o:" + extra_options,
                                        ["source", "header", "prefix=",
                                         "output-dir="] + extra_long_options)
-    except getopt.GetoptError, err:
+    except getopt.GetoptError as err:
         print >>sys.stderr, "%s: %s" % (sys.argv[0], str(err))
         sys.exit(1)
 
@@ -1688,7 +1995,7 @@ def open_output(output_dir, do_c, do_h, prefix, c_file, h_file,
     if output_dir:
         try:
             os.makedirs(output_dir)
-        except os.error, e:
+        except os.error as e:
             if e.errno != errno.EEXIST:
                 raise