xref: /openbmc/qemu/scripts/tracetool/__init__.py (revision bfb27e60) 
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
18import weakref
19
20import tracetool.format
21import tracetool.backend
22import tracetool.transform
23
24
25def error_write(*lines):
26    """Write a set of error lines."""
27    sys.stderr.writelines("\n".join(lines) + "\n")
28
29def error(*lines):
30    """Write a set of error lines and exit."""
31    error_write(*lines)
32    sys.exit(1)
33
34
35def out(*lines, **kwargs):
36    """Write a set of output lines.
37
38    You can use kwargs as a shorthand for mapping variables when formating all
39    the strings in lines.
40    """
41    lines = [ l % kwargs for l in lines ]
42    sys.stdout.writelines("\n".join(lines) + "\n")
43
44
45class Arguments:
46    """Event arguments description."""
47
48    def __init__(self, args):
49        """
50        Parameters
51        ----------
52        args :
53            List of (type, name) tuples.
54        """
55        self._args = args
56
57    def copy(self):
58        """Create a new copy."""
59        return Arguments(list(self._args))
60
61    @staticmethod
62    def build(arg_str):
63        """Build and Arguments instance from an argument string.
64
65        Parameters
66        ----------
67        arg_str : str
68            String describing the event arguments.
69        """
70        res = []
71        for arg in arg_str.split(","):
72            arg = arg.strip()
73            if arg == 'void':
74                continue
75
76            if '*' in arg:
77                arg_type, identifier = arg.rsplit('*', 1)
78                arg_type += '*'
79                identifier = identifier.strip()
80            else:
81                arg_type, identifier = arg.rsplit(None, 1)
82
83            res.append((arg_type, identifier))
84        return Arguments(res)
85
86    def __iter__(self):
87        """Iterate over the (type, name) pairs."""
88        return iter(self._args)
89
90    def __len__(self):
91        """Number of arguments."""
92        return len(self._args)
93
94    def __str__(self):
95        """String suitable for declaring function arguments."""
96        if len(self._args) == 0:
97            return "void"
98        else:
99            return ", ".join([ " ".join([t, n]) for t,n in self._args ])
100
101    def __repr__(self):
102        """Evaluable string representation for this object."""
103        return "Arguments(\"%s\")" % str(self)
104
105    def names(self):
106        """List of argument names."""
107        return [ name for _, name in self._args ]
108
109    def types(self):
110        """List of argument types."""
111        return [ type_ for type_, _ in self._args ]
112
113    def transform(self, *trans):
114        """Return a new Arguments instance with transformed types.
115
116        The types in the resulting Arguments instance are transformed according
117        to tracetool.transform.transform_type.
118        """
119        res = []
120        for type_, name in self._args:
121            res.append((tracetool.transform.transform_type(type_, *trans),
122                        name))
123        return Arguments(res)
124
125
126class Event(object):
127    """Event description.
128
129    Attributes
130    ----------
131    name : str
132        The event name.
133    fmt : str
134        The event format string.
135    properties : set(str)
136        Properties of the event.
137    args : Arguments
138        The event arguments.
139    arg_fmts : str
140        The format strings for each argument.
141    """
142
143    _CRE = re.compile("((?P<props>.*)\s+)?"
144                      "(?P<name>[^(\s]+)"
145                      "\((?P<args>[^)]*)\)"
146                      "\s*"
147                      "(?:(?:(?P<fmt_trans>\".+),)?\s*(?P<fmt>\".+))?"
148                      "\s*")
149    _FMT = re.compile("(%\w+|%.*PRI\S+)")
150
151    _VALID_PROPS = set(["disable", "tcg", "tcg-trans", "tcg-exec"])
152
153    def __init__(self, name, props, fmt, args, arg_fmts, orig=None):
154        """
155        Parameters
156        ----------
157        name : string
158            Event name.
159        props : list of str
160            Property names.
161        fmt : str, list of str
162            Event printing format (or formats).
163        args : Arguments
164            Event arguments.
165        arg_fmts : list of str
166            Format strings for each argument.
167        orig : Event or None
168            Original Event before transformation.
169
170        """
171        self.name = name
172        self.properties = props
173        self.fmt = fmt
174        self.args = args
175        self.arg_fmts = arg_fmts
176
177        if orig is None:
178            self.original = weakref.ref(self)
179        else:
180            self.original = orig
181
182        unknown_props = set(self.properties) - self._VALID_PROPS
183        if len(unknown_props) > 0:
184            raise ValueError("Unknown properties: %s"
185                             % ", ".join(unknown_props))
186        assert isinstance(self.fmt, str) or len(self.fmt) == 2
187
188    def copy(self):
189        """Create a new copy."""
190        return Event(self.name, list(self.properties), self.fmt,
191                     self.args.copy(), self)
192
193    @staticmethod
194    def build(line_str):
195        """Build an Event instance from a string.
196
197        Parameters
198        ----------
199        line_str : str
200            Line describing the event.
201        """
202        m = Event._CRE.match(line_str)
203        assert m is not None
204        groups = m.groupdict('')
205
206        name = groups["name"]
207        props = groups["props"].split()
208        fmt = groups["fmt"]
209        fmt_trans = groups["fmt_trans"]
210        if len(fmt_trans) > 0:
211            fmt = [fmt_trans, fmt]
212        args = Arguments.build(groups["args"])
213        arg_fmts = Event._FMT.findall(fmt)
214
215        if "tcg-trans" in props:
216            raise ValueError("Invalid property 'tcg-trans'")
217        if "tcg-exec" in props:
218            raise ValueError("Invalid property 'tcg-exec'")
219        if "tcg" not in props and not isinstance(fmt, str):
220            raise ValueError("Only events with 'tcg' property can have two formats")
221        if "tcg" in props and isinstance(fmt, str):
222            raise ValueError("Events with 'tcg' property must have two formats")
223
224        return Event(name, props, fmt, args, arg_fmts)
225
226    def __repr__(self):
227        """Evaluable string representation for this object."""
228        if isinstance(self.fmt, str):
229            fmt = self.fmt
230        else:
231            fmt = "%s, %s" % (self.fmt[0], self.fmt[1])
232        return "Event('%s %s(%s) %s')" % (" ".join(self.properties),
233                                          self.name,
234                                          self.args,
235                                          fmt)
236
237    QEMU_TRACE               = "trace_%(name)s"
238    QEMU_TRACE_TCG           = QEMU_TRACE + "_tcg"
239
240    def api(self, fmt=None):
241        if fmt is None:
242            fmt = Event.QEMU_TRACE
243        return fmt % {"name": self.name}
244
245    def transform(self, *trans):
246        """Return a new Event with transformed Arguments."""
247        return Event(self.name,
248                     list(self.properties),
249                     self.fmt,
250                     self.args.transform(*trans),
251                     self)
252
253
254def _read_events(fobj):
255    res = []
256    for line in fobj:
257        if not line.strip():
258            continue
259        if line.lstrip().startswith('#'):
260            continue
261        res.append(Event.build(line))
262    return res
263
264
265class TracetoolError (Exception):
266    """Exception for calls to generate."""
267    pass
268
269
270def try_import(mod_name, attr_name=None, attr_default=None):
271    """Try to import a module and get an attribute from it.
272
273    Parameters
274    ----------
275    mod_name : str
276        Module name.
277    attr_name : str, optional
278        Name of an attribute in the module.
279    attr_default : optional
280        Default value if the attribute does not exist in the module.
281
282    Returns
283    -------
284    A pair indicating whether the module could be imported and the module or
285    object or attribute value.
286    """
287    try:
288        module = __import__(mod_name, globals(), locals(), ["__package__"])
289        if attr_name is None:
290            return True, module
291        return True, getattr(module, str(attr_name), attr_default)
292    except ImportError:
293        return False, None
294
295
296def generate(fevents, format, backends,
297             binary=None, probe_prefix=None):
298    """Generate the output for the given (format, backends) pair.
299
300    Parameters
301    ----------
302    fevents : file
303        Event description file.
304    format : str
305        Output format name.
306    backends : list
307        Output backend names.
308    binary : str or None
309        See tracetool.backend.dtrace.BINARY.
310    probe_prefix : str or None
311        See tracetool.backend.dtrace.PROBEPREFIX.
312    """
313    # fix strange python error (UnboundLocalError tracetool)
314    import tracetool
315
316    format = str(format)
317    if len(format) is 0:
318        raise TracetoolError("format not set")
319    if not tracetool.format.exists(format):
320        raise TracetoolError("unknown format: %s" % format)
321
322    if len(backends) is 0:
323        raise TracetoolError("no backends specified")
324    for backend in backends:
325        if not tracetool.backend.exists(backend):
326            raise TracetoolError("unknown backend: %s" % backend)
327    backend = tracetool.backend.Wrapper(backends, format)
328
329    import tracetool.backend.dtrace
330    tracetool.backend.dtrace.BINARY = binary
331    tracetool.backend.dtrace.PROBEPREFIX = probe_prefix
332
333    events = _read_events(fevents)
334
335    # transform TCG-enabled events
336    new_events = []
337    for event in events:
338        if "tcg" not in event.properties:
339            new_events.append(event)
340        else:
341            event_trans = event.copy()
342            event_trans.name += "_trans"
343            event_trans.properties += ["tcg-trans"]
344            event_trans.fmt = event.fmt[0]
345            args_trans = []
346            for atrans, aorig in zip(
347                    event_trans.transform(tracetool.transform.TCG_2_HOST).args,
348                    event.args):
349                if atrans == aorig:
350                    args_trans.append(atrans)
351            event_trans.args = Arguments(args_trans)
352            event_trans = event_trans.copy()
353
354            event_exec = event.copy()
355            event_exec.name += "_exec"
356            event_exec.properties += ["tcg-exec"]
357            event_exec.fmt = event.fmt[1]
358            event_exec = event_exec.transform(tracetool.transform.TCG_2_HOST)
359
360            new_event = [event_trans, event_exec]
361            event.event_trans, event.event_exec = new_event
362
363            new_events.extend(new_event)
364    events = new_events
365
366    tracetool.format.generate(events, format, backend)
367