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trace: ensure unique function / variable names per .stp file

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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>
This commit is contained in:
Daniel P. Berrange 2017-07-28 14:36:57 +01:00 committed by Stefan Hajnoczi
parent ed8650586f
commit ea1ff54f7d
1 changed files with 19 additions and 10 deletions
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29
scripts/tracetool/format/simpletrace_stap.py
View File

@ -18,29 +18,37 @@ from tracetool.backend.dtrace import binary, probeprefix
from tracetool.backend.simple import is_string
from tracetool.format.stap import stap_escape
def global_var_name(name):
return probeprefix().replace(".", "_") + "_" + name
def generate(events, backend, group):
id_map = global_var_name("event_name_to_id_map")
next_id = global_var_name("event_next_id")
map_func = global_var_name("simple_trace_map_event")
out('/* This file is autogenerated by tracetool, do not edit. */',
'',
'global event_name_to_id_map',
'global event_next_id',
'function simple_trace_map_event(name)',
'global %(id_map)s',
'global %(next_id)s',
'function %(map_func)s(name)',
'',
'{',
' if (!([name] in event_name_to_id_map)) {',
' event_name_to_id_map[name] = event_next_id',
' if (!([name] in %(id_map)s)) {',
' %(id_map)s[name] = %(next_id)s',
' name_len = strlen(name)',
' printf("%%8b%%8b%%4b%%.*s", 0, ',
' event_next_id, name_len, name_len, name)',
' event_next_id = event_next_id + 1',
' %(next_id)s, name_len, name_len, name)',
' %(next_id)s = %(next_id)s + 1',
' }',
' return event_name_to_id_map[name]',
' return %(id_map)s[name]',
'}',
'probe begin',
'{',
' printf("%%8b%%8b%%8b", 0xffffffffffffffff, 0xf2b177cb0aa429b4, 4)',
'}',
'')
'',
id_map=id_map,
next_id=next_id,
map_func=map_func)
for event_id, e in enumerate(events):
if 'disable' in e.properties:
@ -48,8 +56,9 @@ def generate(events, backend, group):
out('probe %(probeprefix)s.simpletrace.%(name)s = %(probeprefix)s.%(name)s ?',
'{',
' id = simple_trace_map_event("%(name)s")',
' id = %(map_func)s("%(name)s")',
probeprefix=probeprefix(),
map_func=map_func,
name=e.name)
# Calculate record size