gecko-dev/memory/replace/dmd/block_analyzer.py

262 строки
7.9 KiB
Python

#!/usr/bin/python
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
# From a scan mode DMD log, extract some information about a
# particular block, such as its allocation stack or which other blocks
# contain pointers to it. This can be useful when investigating leaks
# caused by unknown references to refcounted objects.
import json
import gzip
import sys
import argparse
import re
# The DMD output version this script handles.
outputVersion = 5
# If --ignore-alloc-fns is specified, stack frames containing functions that
# match these strings will be removed from the *start* of stack traces. (Once
# we hit a non-matching frame, any subsequent frames won't be removed even if
# they do match.)
allocatorFns = [
'malloc (',
'replace_malloc',
'replace_calloc',
'replace_realloc',
'replace_memalign',
'replace_posix_memalign',
'malloc_zone_malloc',
'moz_xmalloc',
'moz_xcalloc',
'moz_xrealloc',
'operator new(',
'operator new[](',
'g_malloc',
'g_slice_alloc',
'callocCanGC',
'reallocCanGC',
'vpx_malloc',
'vpx_calloc',
'vpx_realloc',
'vpx_memalign',
'js_malloc',
'js_calloc',
'js_realloc',
'pod_malloc',
'pod_calloc',
'pod_realloc',
'nsTArrayInfallibleAllocator::Malloc',
# This one necessary to fully filter some sequences of allocation functions
# that happen in practice. Note that ??? entries that follow non-allocation
# functions won't be stripped, as explained above.
'???',
]
####
# Command line arguments
def range_1_24(string):
value = int(string)
if value < 1 or value > 24:
msg = '{:s} is not in the range 1..24'.format(string)
raise argparse.ArgumentTypeError(msg)
return value
parser = argparse.ArgumentParser(description='Analyze the heap graph to find out things about an object. \
By default this prints out information about blocks that point to the given block.')
parser.add_argument('dmd_log_file_name',
help='clamped DMD log file name')
parser.add_argument('block',
help='address of the block of interest')
parser.add_argument('--info', dest='info', action='store_true',
default=False,
help='Print out information about the block.')
parser.add_argument('-sfl', '--max-stack-frame-length', type=int,
default=150,
help='Maximum number of characters to print from each stack frame')
parser.add_argument('-a', '--ignore-alloc-fns', action='store_true',
help='ignore allocation functions at the start of traces')
parser.add_argument('-f', '--max-frames', type=range_1_24,
help='maximum number of frames to consider in each trace')
parser.add_argument('-c', '--chain-reports', action='store_true',
help='if only one block is found to hold onto the object, report the next one, too')
####
class BlockData:
def __init__(self, json_block):
self.addr = json_block['addr']
if 'contents' in json_block:
contents = json_block['contents']
else:
contents = []
self.contents = []
for c in contents:
self.contents.append(int(c, 16))
self.req_size = json_block['req']
self.alloc_stack = json_block['alloc']
def print_trace_segment(args, stacks, block):
(traceTable, frameTable) = stacks
for l in traceTable[block.alloc_stack]:
# The 5: is to remove the bogus leading "#00: " from the stack frame.
print ' ', frameTable[l][5:args.max_stack_frame_length]
def show_referrers(args, blocks, stacks, block):
visited = set([])
anyFound = False
while True:
referrers = {}
for b, data in blocks.iteritems():
which_edge = 0
for e in data.contents:
if e == block:
# 8 is the number of bytes per word on a 64-bit system.
# XXX This means that this output will be wrong for logs from 32-bit systems!
referrers.setdefault(b, []).append(8 * which_edge)
anyFound = True
which_edge += 1
for r in referrers:
sys.stdout.write('0x{} size = {} bytes'.format(blocks[r].addr, blocks[r].req_size))
plural = 's' if len(referrers[r]) > 1 else ''
sys.stdout.write(' at byte offset' + plural + ' ' + (', '.join(str(x) for x in referrers[r])))
print
print_trace_segment(args, stacks, blocks[r])
print
if args.chain_reports:
if len(referrers) == 0:
sys.stdout.write('Found no more referrers.\n')
break
if len(referrers) > 1:
sys.stdout.write('Found too many referrers.\n')
break
sys.stdout.write('Chaining to next referrer.\n\n')
for r in referrers:
block = r
if block in visited:
sys.stdout.write('Found a loop.\n')
break
visited.add(block)
else:
break
if not anyFound:
print 'No referrers found.'
def show_block_info(args, blocks, stacks, block):
b = blocks[block]
sys.stdout.write('block: 0x{}\n'.format(b.addr))
sys.stdout.write('requested size: {} bytes\n'.format(b.req_size))
sys.stdout.write('\n')
sys.stdout.write('block contents: ')
for c in b.contents:
v = '0' if c == 0 else blocks[c].addr
sys.stdout.write('0x{} '.format(v))
sys.stdout.write('\n\n')
sys.stdout.write('allocation stack:\n')
print_trace_segment(args, stacks, b)
return
def cleanupTraceTable(args, frameTable, traceTable):
# Remove allocation functions at the start of traces.
if args.ignore_alloc_fns:
# Build a regexp that matches every function in allocatorFns.
escapedAllocatorFns = map(re.escape, allocatorFns)
fn_re = re.compile('|'.join(escapedAllocatorFns))
# Remove allocator fns from each stack trace.
for traceKey, frameKeys in traceTable.items():
numSkippedFrames = 0
for frameKey in frameKeys:
frameDesc = frameTable[frameKey]
if re.search(fn_re, frameDesc):
numSkippedFrames += 1
else:
break
if numSkippedFrames > 0:
traceTable[traceKey] = frameKeys[numSkippedFrames:]
# Trim the number of frames.
for traceKey, frameKeys in traceTable.items():
if len(frameKeys) > args.max_frames:
traceTable[traceKey] = frameKeys[:args.max_frames]
def loadGraph(options):
# Handle gzipped input if necessary.
isZipped = options.dmd_log_file_name.endswith('.gz')
opener = gzip.open if isZipped else open
with opener(options.dmd_log_file_name, 'rb') as f:
j = json.load(f)
if j['version'] != outputVersion:
raise Exception("'version' property isn't '{:d}'".format(outputVersion))
invocation = j['invocation']
block_list = j['blockList']
blocks = {}
for json_block in block_list:
blocks[int(json_block['addr'], 16)] = BlockData(json_block)
traceTable = j['traceTable']
frameTable = j['frameTable']
cleanupTraceTable(options, frameTable, traceTable)
return (blocks, (traceTable, frameTable))
def analyzeLogs():
options = parser.parse_args()
(blocks, stacks) = loadGraph(options)
block = int(options.block, 16)
if not block in blocks:
print 'Object', block, 'not found in traces.'
print 'It could still be the target of some nodes.'
return
if options.info:
show_block_info(options, blocks, stacks, block)
return
show_referrers(options, blocks, stacks, block)
if __name__ == "__main__":
analyzeLogs()