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