qemu-e2k/scripts/tracetool/__init__.py

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#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Machinery for generating tracing-related intermediate files.
"""
__author__ = "Lluís Vilanova <vilanova@ac.upc.edu>"
__copyright__ = "Copyright 2012, Lluís Vilanova <vilanova@ac.upc.edu>"
__license__ = "GPL version 2 or (at your option) any later version"
__maintainer__ = "Stefan Hajnoczi"
__email__ = "stefanha@linux.vnet.ibm.com"
import re
import sys
import tracetool.format
import tracetool.backend
def error_write(*lines):
"""Write a set of error lines."""
sys.stderr.writelines("\n".join(lines) + "\n")
def error(*lines):
"""Write a set of error lines and exit."""
error_write(*lines)
sys.exit(1)
def out(*lines, **kwargs):
"""Write a set of output lines.
You can use kwargs as a shorthand for mapping variables when formating all
the strings in lines.
"""
lines = [ l % kwargs for l in lines ]
sys.stdout.writelines("\n".join(lines) + "\n")
class Arguments:
"""Event arguments description."""
def __init__(self, args):
"""
Parameters
----------
args :
List of (type, name) tuples.
"""
self._args = args
@staticmethod
def build(arg_str):
"""Build and Arguments instance from an argument string.
Parameters
----------
arg_str : str
String describing the event arguments.
"""
res = []
for arg in arg_str.split(","):
arg = arg.strip()
if arg == 'void':
continue
if '*' in arg:
arg_type, identifier = arg.rsplit('*', 1)
arg_type += '*'
identifier = identifier.strip()
else:
arg_type, identifier = arg.rsplit(None, 1)
res.append((arg_type, identifier))
return Arguments(res)
def __iter__(self):
"""Iterate over the (type, name) pairs."""
return iter(self._args)
def __len__(self):
"""Number of arguments."""
return len(self._args)
def __str__(self):
"""String suitable for declaring function arguments."""
if len(self._args) == 0:
return "void"
else:
return ", ".join([ " ".join([t, n]) for t,n in self._args ])
def __repr__(self):
"""Evaluable string representation for this object."""
return "Arguments(\"%s\")" % str(self)
def names(self):
"""List of argument names."""
return [ name for _, name in self._args ]
def types(self):
"""List of argument types."""
return [ type_ for type_, _ in self._args ]
class Event(object):
"""Event description.
Attributes
----------
name : str
The event name.
fmt : str
The event format string.
properties : set(str)
Properties of the event.
args : Arguments
The event arguments.
"""
_CRE = re.compile("((?P<props>.*)\s+)?(?P<name>[^(\s]+)\((?P<args>[^)]*)\)\s*(?P<fmt>\".*)?")
_VALID_PROPS = set(["disable"])
def __init__(self, name, props, fmt, args):
"""
Parameters
----------
name : string
Event name.
props : list of str
Property names.
fmt : str
Event printing format.
args : Arguments
Event arguments.
"""
self.name = name
self.properties = props
self.fmt = fmt
self.args = args
unknown_props = set(self.properties) - self._VALID_PROPS
if len(unknown_props) > 0:
raise ValueError("Unknown properties: %s" % ", ".join(unknown_props))
@staticmethod
def build(line_str):
"""Build an Event instance from a string.
Parameters
----------
line_str : str
Line describing the event.
"""
m = Event._CRE.match(line_str)
assert m is not None
groups = m.groupdict('')
name = groups["name"]
props = groups["props"].split()
fmt = groups["fmt"]
args = Arguments.build(groups["args"])
return Event(name, props, fmt, args)
def __repr__(self):
"""Evaluable string representation for this object."""
return "Event('%s %s(%s) %s')" % (" ".join(self.properties),
self.name,
self.args,
self.fmt)
def _read_events(fobj):
res = []
for line in fobj:
if not line.strip():
continue
if line.lstrip().startswith('#'):
continue
res.append(Event.build(line))
return res
class TracetoolError (Exception):
"""Exception for calls to generate."""
pass
def try_import(mod_name, attr_name = None, attr_default = None):
"""Try to import a module and get an attribute from it.
Parameters
----------
mod_name : str
Module name.
attr_name : str, optional
Name of an attribute in the module.
attr_default : optional
Default value if the attribute does not exist in the module.
Returns
-------
A pair indicating whether the module could be imported and the module or
object or attribute value.
"""
try:
module = __import__(mod_name, globals(), locals(), ["__package__"])
if attr_name is None:
return True, module
return True, getattr(module, str(attr_name), attr_default)
except ImportError:
return False, None
def generate(fevents, format, backend,
binary = None, probe_prefix = None):
"""Generate the output for the given (format, backend) pair.
Parameters
----------
fevents : file
Event description file.
format : str
Output format name.
backend : str
Output backend name.
binary : str or None
See tracetool.backend.dtrace.BINARY.
probe_prefix : str or None
See tracetool.backend.dtrace.PROBEPREFIX.
"""
# fix strange python error (UnboundLocalError tracetool)
import tracetool
format = str(format)
if len(format) is 0:
raise TracetoolError("format not set")
mformat = format.replace("-", "_")
if not tracetool.format.exists(mformat):
raise TracetoolError("unknown format: %s" % format)
backend = str(backend)
if len(backend) is 0:
raise TracetoolError("backend not set")
mbackend = backend.replace("-", "_")
if not tracetool.backend.exists(mbackend):
raise TracetoolError("unknown backend: %s" % backend)
if not tracetool.backend.compatible(mbackend, mformat):
raise TracetoolError("backend '%s' not compatible with format '%s'" %
(backend, format))
import tracetool.backend.dtrace
tracetool.backend.dtrace.BINARY = binary
tracetool.backend.dtrace.PROBEPREFIX = probe_prefix
events = _read_events(fevents)
if backend == "nop":
( e.properies.add("disable") for e in events )
tracetool.format.generate_begin(mformat, events)
tracetool.backend.generate("nop", format,
[ e
for e in events
if "disable" in e.properties ])
tracetool.backend.generate(backend, format,
[ e
for e in events
if "disable" not in e.properties ])
tracetool.format.generate_end(mformat, events)