scripts/tracetool/__init__.py

   1 #!/usr/bin/env python
   2 # -*- coding: utf-8 -*-
   3
   4 """
   5 Machinery for generating tracing-related intermediate files.
   6 """
   7
   8 __author__     = "Lluís Vilanova <vilanova@ac.upc.edu>"
   9 __copyright__  = "Copyright 2012, 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
  16 import re
  17 import sys
  18
  19 import tracetool.format
  20 import tracetool.backend
  21
  22
  23 def error_write(*lines):
  24     """Write a set of error lines."""
  25     sys.stderr.writelines("\n".join(lines) + "\n")
  26
  27 def error(*lines):
  28     """Write a set of error lines and exit."""
  29     error_write(*lines)
  30     sys.exit(1)
  31
  32
  33 def 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
  43 class 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     @staticmethod
  56     def build(arg_str):
  57         """Build and Arguments instance from an argument string.
  58
  59         Parameters
  60         ----------
  61         arg_str : str
  62             String describing the event arguments.
  63         """
  64         res = []
  65         for arg in arg_str.split(","):
  66             arg = arg.strip()
  67             parts = arg.split()
  68             head, sep, tail = parts[-1].rpartition("*")
  69             parts = parts[:-1]
  70             if tail == "void":
  71                 assert len(parts) == 0 and sep == ""
  72                 continue
  73             arg_type = " ".join(parts + [ " ".join([head, sep]).strip() ]).strip()
  74             res.append((arg_type, tail))
  75         return Arguments(res)
  76
  77     def __iter__(self):
  78         """Iterate over the (type, name) pairs."""
  79         return iter(self._args)
  80
  81     def __len__(self):
  82         """Number of arguments."""
  83         return len(self._args)
  84
  85     def __str__(self):
  86         """String suitable for declaring function arguments."""
  87         if len(self._args) == 0:
  88             return "void"
  89         else:
  90             return ", ".join([ " ".join([t, n]) for t,n in self._args ])
  91
  92     def __repr__(self):
  93         """Evaluable string representation for this object."""
  94         return "Arguments(\"%s\")" % str(self)
  95
  96     def names(self):
  97         """List of argument names."""
  98         return [ name for _, name in self._args ]
  99
 100     def types(self):
 101         """List of argument types."""
 102         return [ type_ for type_, _ in self._args ]
 103
 104
 105 class Event(object):
 106     """Event description.
 107
 108     Attributes
 109     ----------
 110     name : str
 111         The event name.
 112     fmt : str
 113         The event format string.
 114     properties : set(str)
 115         Properties of the event.
 116     args : Arguments
 117         The event arguments.
 118     """
 119
 120     _CRE = re.compile("((?P<props>.*)\s+)?(?P<name>[^(\s]+)\((?P<args>[^)]*)\)\s*(?P<fmt>\".*)?")
 121
 122     _VALID_PROPS = set(["disable"])
 123
 124     def __init__(self, name, props, fmt, args):
 125         """
 126         Parameters
 127         ----------
 128         name : string
 129             Event name.
 130         props : list of str
 131             Property names.
 132         fmt : str
 133             Event printing format.
 134         args : Arguments
 135             Event arguments.
 136         """
 137         self.name = name
 138         self.properties = props
 139         self.fmt = fmt
 140         self.args = args
 141
 142         unknown_props = set(self.properties) - self._VALID_PROPS
 143         if len(unknown_props) > 0:
 144             raise ValueError("Unknown properties: %s" % ", ".join(unknown_props))
 145
 146     @staticmethod
 147     def build(line_str):
 148         """Build an Event instance from a string.
 149
 150         Parameters
 151         ----------
 152         line_str : str
 153             Line describing the event.
 154         """
 155         m = Event._CRE.match(line_str)
 156         assert m is not None
 157         groups = m.groupdict('')
 158
 159         name = groups["name"]
 160         props = groups["props"].split()
 161         fmt = groups["fmt"]
 162         args = Arguments.build(groups["args"])
 163
 164         return Event(name, props, fmt, args)
 165
 166     def __repr__(self):
 167         """Evaluable string representation for this object."""
 168         return "Event('%s %s(%s) %s')" % (" ".join(self.properties),
 169                                           self.name,
 170                                           self.args,
 171                                           self.fmt)
 172
 173 def _read_events(fobj):
 174     res = []
 175     for line in fobj:
 176         if not line.strip():
 177             continue
 178         if line.lstrip().startswith('#'):
 179             continue
 180         res.append(Event.build(line))
 181     return res
 182
 183
 184 class TracetoolError (Exception):
 185     """Exception for calls to generate."""
 186     pass
 187
 188
 189 def try_import(mod_name, attr_name = None, attr_default = None):
 190     """Try to import a module and get an attribute from it.
 191
 192     Parameters
 193     ----------
 194     mod_name : str
 195         Module name.
 196     attr_name : str, optional
 197         Name of an attribute in the module.
 198     attr_default : optional
 199         Default value if the attribute does not exist in the module.
 200
 201     Returns
 202     -------
 203     A pair indicating whether the module could be imported and the module or
 204     object or attribute value.
 205     """
 206     try:
 207         module = __import__(mod_name, fromlist=["__package__"])
 208         if attr_name is None:
 209             return True, module
 210         return True, getattr(module, str(attr_name), attr_default)
 211     except ImportError:
 212         return False, None
 213
 214
 215 def generate(fevents, format, backend,
 216              binary = None, probe_prefix = None):
 217     """Generate the output for the given (format, backend) pair.
 218
 219     Parameters
 220     ----------
 221     fevents : file
 222         Event description file.
 223     format : str
 224         Output format name.
 225     backend : str
 226         Output backend name.
 227     binary : str or None
 228         See tracetool.backend.dtrace.BINARY.
 229     probe_prefix : str or None
 230         See tracetool.backend.dtrace.PROBEPREFIX.
 231     """
 232     # fix strange python error (UnboundLocalError tracetool)
 233     import tracetool
 234
 235     format = str(format)
 236     if len(format) is 0:
 237         raise TracetoolError("format not set")
 238     mformat = format.replace("-", "_")
 239     if not tracetool.format.exists(mformat):
 240         raise TracetoolError("unknown format: %s" % format)
 241
 242     backend = str(backend)
 243     if len(backend) is 0:
 244         raise TracetoolError("backend not set")
 245     mbackend = backend.replace("-", "_")
 246     if not tracetool.backend.exists(mbackend):
 247         raise TracetoolError("unknown backend: %s" % backend)
 248
 249     if not tracetool.backend.compatible(mbackend, mformat):
 250         raise TracetoolError("backend '%s' not compatible with format '%s'" %
 251                              (backend, format))
 252
 253     import tracetool.backend.dtrace
 254     tracetool.backend.dtrace.BINARY = binary
 255     tracetool.backend.dtrace.PROBEPREFIX = probe_prefix
 256
 257     events = _read_events(fevents)
 258
 259     if backend == "nop":
 260         ( e.properies.add("disable") for e in events )
 261
 262     tracetool.format.generate_begin(mformat, events)
 263     tracetool.backend.generate("nop", format,
 264                                [ e
 265                                  for e in events
 266                                  if "disable" in e.properties ])
 267     tracetool.backend.generate(backend, format,
 268                                [ e
 269                                  for e in events
 270                                  if "disable" not in e.properties ])
 271     tracetool.format.generate_end(mformat, events)