mirror of https://github.com/python/cpython
129 lines
4.3 KiB
Python
Executable File
129 lines
4.3 KiB
Python
Executable File
#! /usr/bin/env python3
|
|
|
|
"""
|
|
combinerefs path
|
|
|
|
A helper for analyzing PYTHONDUMPREFS output.
|
|
|
|
When the PYTHONDUMPREFS envar is set in a debug build, at Python shutdown
|
|
time Py_FinalizeEx() prints the list of all live objects twice: first it
|
|
prints the repr() of each object while the interpreter is still fully intact.
|
|
After cleaning up everything it can, it prints all remaining live objects
|
|
again, but the second time just prints their addresses, refcounts, and type
|
|
names (because the interpreter has been torn down, calling repr methods at
|
|
this point can get into infinite loops or blow up).
|
|
|
|
Save all this output into a file, then run this script passing the path to
|
|
that file. The script finds both output chunks, combines them, then prints
|
|
a line of output for each object still alive at the end:
|
|
|
|
address refcnt typename repr
|
|
|
|
address is the address of the object, in whatever format the platform C
|
|
produces for a %p format code.
|
|
|
|
refcnt is of the form
|
|
|
|
"[" ref "]"
|
|
|
|
when the object's refcount is the same in both PYTHONDUMPREFS output blocks,
|
|
or
|
|
|
|
"[" ref_before "->" ref_after "]"
|
|
|
|
if the refcount changed.
|
|
|
|
typename is object->ob_type->tp_name, extracted from the second PYTHONDUMPREFS
|
|
output block.
|
|
|
|
repr is repr(object), extracted from the first PYTHONDUMPREFS output block.
|
|
CAUTION: If object is a container type, it may not actually contain all the
|
|
objects shown in the repr: the repr was captured from the first output block,
|
|
and some of the containees may have been released since then. For example,
|
|
it's common for the line showing the dict of interned strings to display
|
|
strings that no longer exist at the end of Py_FinalizeEx; this can be recognized
|
|
(albeit painfully) because such containees don't have a line of their own.
|
|
|
|
The objects are listed in allocation order, with most-recently allocated
|
|
printed first, and the first object allocated printed last.
|
|
|
|
|
|
Simple examples:
|
|
|
|
00857060 [14] str '__len__'
|
|
|
|
The str object '__len__' is alive at shutdown time, and both PYTHONDUMPREFS
|
|
output blocks said there were 14 references to it. This is probably due to
|
|
C modules that intern the string "__len__" and keep a reference to it in a
|
|
file static.
|
|
|
|
00857038 [46->5] tuple ()
|
|
|
|
46-5 = 41 references to the empty tuple were removed by the cleanup actions
|
|
between the times PYTHONDUMPREFS produced output.
|
|
|
|
00858028 [1025->1456] str '<dummy key>'
|
|
|
|
The string '<dummy key>', which is used in dictobject.c to overwrite a real
|
|
key that gets deleted, grew several hundred references during cleanup. It
|
|
suggests that stuff did get removed from dicts by cleanup, but that the dicts
|
|
themselves are staying alive for some reason. """
|
|
|
|
import re
|
|
import sys
|
|
|
|
# Generate lines from fileiter. If whilematch is true, continue reading
|
|
# while the regexp object pat matches line. If whilematch is false, lines
|
|
# are read so long as pat doesn't match them. In any case, the first line
|
|
# that doesn't match pat (when whilematch is true), or that does match pat
|
|
# (when whilematch is false), is lost, and fileiter will resume at the line
|
|
# following it.
|
|
def read(fileiter, pat, whilematch):
|
|
for line in fileiter:
|
|
if bool(pat.match(line)) == whilematch:
|
|
yield line
|
|
else:
|
|
break
|
|
|
|
def combine(fname):
|
|
f = open(fname)
|
|
|
|
fi = iter(f)
|
|
|
|
for line in read(fi, re.compile(r'^Remaining objects:$'), False):
|
|
pass
|
|
|
|
crack = re.compile(r'([a-zA-Z\d]+) \[(\d+)\] (.*)')
|
|
addr2rc = {}
|
|
addr2guts = {}
|
|
before = 0
|
|
for line in read(fi, re.compile(r'^Remaining object addresses:$'), False):
|
|
m = crack.match(line)
|
|
if m:
|
|
addr, addr2rc[addr], addr2guts[addr] = m.groups()
|
|
before += 1
|
|
else:
|
|
print('??? skipped:', line)
|
|
|
|
after = 0
|
|
for line in read(fi, crack, True):
|
|
after += 1
|
|
m = crack.match(line)
|
|
assert m
|
|
addr, rc, guts = m.groups() # guts is type name here
|
|
if addr not in addr2rc:
|
|
print('??? new object created while tearing down:', line.rstrip())
|
|
continue
|
|
print(addr, end=' ')
|
|
if rc == addr2rc[addr]:
|
|
print('[%s]' % rc, end=' ')
|
|
else:
|
|
print('[%s->%s]' % (addr2rc[addr], rc), end=' ')
|
|
print(guts, addr2guts[addr])
|
|
|
|
f.close()
|
|
print("%d objects before, %d after" % (before, after))
|
|
|
|
if __name__ == '__main__':
|
|
combine(sys.argv[1])
|