xref: /openbmc/qemu/scripts/tracetool/__init__.py (revision acb0ef58)
1#!/usr/bin/env python
2# -*- coding: utf-8 -*-
3
4"""
5Machinery for generating tracing-related intermediate files.
6"""
7
8__author__     = "Lluís Vilanova <vilanova@ac.upc.edu>"
9__copyright__  = "Copyright 2012-2014, Lluís Vilanova <vilanova@ac.upc.edu>"
10__license__    = "GPL version 2 or (at your option) any later version"
11
12__maintainer__ = "Stefan Hajnoczi"
13__email__      = "stefanha@linux.vnet.ibm.com"
14
15
16import re
17import sys
18
19import tracetool.format
20import tracetool.backend
21
22
23def error_write(*lines):
24    """Write a set of error lines."""
25    sys.stderr.writelines("\n".join(lines) + "\n")
26
27def error(*lines):
28    """Write a set of error lines and exit."""
29    error_write(*lines)
30    sys.exit(1)
31
32
33def out(*lines, **kwargs):
34    """Write a set of output lines.
35
36    You can use kwargs as a shorthand for mapping variables when formating all
37    the strings in lines.
38    """
39    lines = [ l % kwargs for l in lines ]
40    sys.stdout.writelines("\n".join(lines) + "\n")
41
42
43class Arguments:
44    """Event arguments description."""
45
46    def __init__(self, args):
47        """
48        Parameters
49        ----------
50        args :
51            List of (type, name) tuples.
52        """
53        self._args = args
54
55    def copy(self):
56        """Create a new copy."""
57        return Arguments(list(self._args))
58
59    @staticmethod
60    def build(arg_str):
61        """Build and Arguments instance from an argument string.
62
63        Parameters
64        ----------
65        arg_str : str
66            String describing the event arguments.
67        """
68        res = []
69        for arg in arg_str.split(","):
70            arg = arg.strip()
71            if arg == 'void':
72                continue
73
74            if '*' in arg:
75                arg_type, identifier = arg.rsplit('*', 1)
76                arg_type += '*'
77                identifier = identifier.strip()
78            else:
79                arg_type, identifier = arg.rsplit(None, 1)
80
81            res.append((arg_type, identifier))
82        return Arguments(res)
83
84    def __iter__(self):
85        """Iterate over the (type, name) pairs."""
86        return iter(self._args)
87
88    def __len__(self):
89        """Number of arguments."""
90        return len(self._args)
91
92    def __str__(self):
93        """String suitable for declaring function arguments."""
94        if len(self._args) == 0:
95            return "void"
96        else:
97            return ", ".join([ " ".join([t, n]) for t,n in self._args ])
98
99    def __repr__(self):
100        """Evaluable string representation for this object."""
101        return "Arguments(\"%s\")" % str(self)
102
103    def names(self):
104        """List of argument names."""
105        return [ name for _, name in self._args ]
106
107    def types(self):
108        """List of argument types."""
109        return [ type_ for type_, _ in self._args ]
110
111
112class Event(object):
113    """Event description.
114
115    Attributes
116    ----------
117    name : str
118        The event name.
119    fmt : str
120        The event format string.
121    properties : set(str)
122        Properties of the event.
123    args : Arguments
124        The event arguments.
125    """
126
127    _CRE = re.compile("((?P<props>.*)\s+)?(?P<name>[^(\s]+)\((?P<args>[^)]*)\)\s*(?P<fmt>\".*)?")
128
129    _VALID_PROPS = set(["disable"])
130
131    def __init__(self, name, props, fmt, args):
132        """
133        Parameters
134        ----------
135        name : string
136            Event name.
137        props : list of str
138            Property names.
139        fmt : str
140            Event printing format.
141        args : Arguments
142            Event arguments.
143        """
144        self.name = name
145        self.properties = props
146        self.fmt = fmt
147        self.args = args
148
149        unknown_props = set(self.properties) - self._VALID_PROPS
150        if len(unknown_props) > 0:
151            raise ValueError("Unknown properties: %s"
152                             % ", ".join(unknown_props))
153
154    def copy(self):
155        """Create a new copy."""
156        return Event(self.name, list(self.properties), self.fmt,
157                     self.args.copy(), self)
158
159    @staticmethod
160    def build(line_str):
161        """Build an Event instance from a string.
162
163        Parameters
164        ----------
165        line_str : str
166            Line describing the event.
167        """
168        m = Event._CRE.match(line_str)
169        assert m is not None
170        groups = m.groupdict('')
171
172        name = groups["name"]
173        props = groups["props"].split()
174        fmt = groups["fmt"]
175        args = Arguments.build(groups["args"])
176
177        return Event(name, props, fmt, args)
178
179    def __repr__(self):
180        """Evaluable string representation for this object."""
181        return "Event('%s %s(%s) %s')" % (" ".join(self.properties),
182                                          self.name,
183                                          self.args,
184                                          self.fmt)
185
186    QEMU_TRACE               = "trace_%(name)s"
187
188    def api(self, fmt=None):
189        if fmt is None:
190            fmt = Event.QEMU_TRACE
191        return fmt % {"name": self.name}
192
193
194def _read_events(fobj):
195    res = []
196    for line in fobj:
197        if not line.strip():
198            continue
199        if line.lstrip().startswith('#'):
200            continue
201        res.append(Event.build(line))
202    return res
203
204
205class TracetoolError (Exception):
206    """Exception for calls to generate."""
207    pass
208
209
210def try_import(mod_name, attr_name=None, attr_default=None):
211    """Try to import a module and get an attribute from it.
212
213    Parameters
214    ----------
215    mod_name : str
216        Module name.
217    attr_name : str, optional
218        Name of an attribute in the module.
219    attr_default : optional
220        Default value if the attribute does not exist in the module.
221
222    Returns
223    -------
224    A pair indicating whether the module could be imported and the module or
225    object or attribute value.
226    """
227    try:
228        module = __import__(mod_name, globals(), locals(), ["__package__"])
229        if attr_name is None:
230            return True, module
231        return True, getattr(module, str(attr_name), attr_default)
232    except ImportError:
233        return False, None
234
235
236def generate(fevents, format, backends,
237             binary=None, probe_prefix=None):
238    """Generate the output for the given (format, backends) pair.
239
240    Parameters
241    ----------
242    fevents : file
243        Event description file.
244    format : str
245        Output format name.
246    backends : list
247        Output backend names.
248    binary : str or None
249        See tracetool.backend.dtrace.BINARY.
250    probe_prefix : str or None
251        See tracetool.backend.dtrace.PROBEPREFIX.
252    """
253    # fix strange python error (UnboundLocalError tracetool)
254    import tracetool
255
256    format = str(format)
257    if len(format) is 0:
258        raise TracetoolError("format not set")
259    if not tracetool.format.exists(format):
260        raise TracetoolError("unknown format: %s" % format)
261
262    if len(backends) is 0:
263        raise TracetoolError("no backends specified")
264    for backend in backends:
265        if not tracetool.backend.exists(backend):
266            raise TracetoolError("unknown backend: %s" % backend)
267    backend = tracetool.backend.Wrapper(backends, format)
268
269    import tracetool.backend.dtrace
270    tracetool.backend.dtrace.BINARY = binary
271    tracetool.backend.dtrace.PROBEPREFIX = probe_prefix
272
273    events = _read_events(fevents)
274
275    tracetool.format.generate(events, format, backend)
276