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