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ea1ff54f7d
The simpletrace compatibility code for systemtap creates a
function and some global variables for mapping to event ID
numbers. We generate multiple -simpletrace.stp files though,
one per target and systemtap considers functions & variables
to be globally scoped, not per file. So if trying to use the
simpletrace compat probes, systemtap will complain:
# stap -e 'probe qemu.system.arm.simpletrace.visit_type_str { print( "hello")}'
semantic error: conflicting global variables: identifier 'event_name_to_id_map' at /usr/share/systemtap/tapset/qemu-aarch64-simpletrace.stp:3:8
source: global event_name_to_id_map
^
identifier 'event_name_to_id_map' at /usr/share/systemtap/tapset/qemu-system-arm-simpletrace.stp:3:8
source: global event_name_to_id_map
^
WARNING: cross-file global variable reference to identifier 'event_name_to_id_map' at /usr/share/systemtap/tapset/qemu-system-arm-simpletrace.stp:3:8 from: identifier 'event_name_to_id_map' at /usr/share/systemtap/tapset/qemu-aarch64-simpletrace.stp:8:21
source: if (!([name] in event_name_to_id_map)) {
^
WARNING: cross-file global variable reference to identifier 'event_next_id' at /usr/share/systemtap/tapset/qemu-system-arm-simpletrace.stp:4:8 from: identifier 'event_next_id' at :9:38
source: event_name_to_id_map[name] = event_next_id
^
We already have a string used to prefix probe names, so just
replace '.' with '_' to get a function / variable name prefix
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170728133657.5525-1-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
100 lines
3.4 KiB
Python
100 lines
3.4 KiB
Python
#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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"""
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Generate .stp file that outputs simpletrace binary traces (DTrace with SystemTAP only).
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"""
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__author__ = "Stefan Hajnoczi <redhat.com>"
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__copyright__ = "Copyright (C) 2014, Red Hat, Inc."
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__license__ = "GPL version 2 or (at your option) any later version"
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__maintainer__ = "Stefan Hajnoczi"
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__email__ = "stefanha@redhat.com"
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from tracetool import out
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from tracetool.backend.dtrace import binary, probeprefix
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from tracetool.backend.simple import is_string
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from tracetool.format.stap import stap_escape
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def global_var_name(name):
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return probeprefix().replace(".", "_") + "_" + name
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def generate(events, backend, group):
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id_map = global_var_name("event_name_to_id_map")
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next_id = global_var_name("event_next_id")
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map_func = global_var_name("simple_trace_map_event")
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out('/* This file is autogenerated by tracetool, do not edit. */',
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'',
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'global %(id_map)s',
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'global %(next_id)s',
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'function %(map_func)s(name)',
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'',
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'{',
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' if (!([name] in %(id_map)s)) {',
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' %(id_map)s[name] = %(next_id)s',
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' name_len = strlen(name)',
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' printf("%%8b%%8b%%4b%%.*s", 0, ',
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' %(next_id)s, name_len, name_len, name)',
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' %(next_id)s = %(next_id)s + 1',
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' }',
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' return %(id_map)s[name]',
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'}',
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'probe begin',
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'{',
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' printf("%%8b%%8b%%8b", 0xffffffffffffffff, 0xf2b177cb0aa429b4, 4)',
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'}',
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'',
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id_map=id_map,
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next_id=next_id,
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map_func=map_func)
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for event_id, e in enumerate(events):
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if 'disable' in e.properties:
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continue
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out('probe %(probeprefix)s.simpletrace.%(name)s = %(probeprefix)s.%(name)s ?',
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'{',
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' id = %(map_func)s("%(name)s")',
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probeprefix=probeprefix(),
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map_func=map_func,
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name=e.name)
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# Calculate record size
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sizes = ['24'] # sizeof(TraceRecord)
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for type_, name in e.args:
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name = stap_escape(name)
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if is_string(type_):
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out(' try {',
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' arg%(name)s_str = %(name)s ? user_string_n(%(name)s, 512) : "<null>"',
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' } catch {}',
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' arg%(name)s_len = strlen(arg%(name)s_str)',
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name=name)
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sizes.append('4 + arg%s_len' % name)
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else:
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sizes.append('8')
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sizestr = ' + '.join(sizes)
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# Generate format string and value pairs for record header and arguments
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fields = [('8b', 'id'),
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('8b', 'gettimeofday_ns()'),
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('4b', sizestr),
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('4b', 'pid()')]
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for type_, name in e.args:
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name = stap_escape(name)
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if is_string(type_):
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fields.extend([('4b', 'arg%s_len' % name),
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('.*s', 'arg%s_len, arg%s_str' % (name, name))])
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else:
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fields.append(('8b', name))
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# Emit the entire record in a single SystemTap printf()
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fmt_str = '%'.join(fmt for fmt, _ in fields)
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arg_str = ', '.join(arg for _, arg in fields)
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out(' printf("%%8b%%%(fmt_str)s", 1, %(arg_str)s)',
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fmt_str=fmt_str, arg_str=arg_str)
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out('}')
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out()
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