[fuzzer] Script to detect unbalanced allocation in -trace_malloc output

#!/usr/bin/env python

#===- lib/fuzzer/scripts/unbalanced_allocs.py ------------------------------===#

#

#                     The LLVM Compiler Infrastructure

#

# This file is distributed under the University of Illinois Open Source

# License. See LICENSE.TXT for details.

#

#===------------------------------------------------------------------------===#

#

# Post-process -trace_malloc=2 output and printout only allocations and frees

# unbalanced inside of fuzzer runs.

# Usage:

#   my_fuzzer -trace_malloc=2 -runs=10 2>&1 | unbalanced_allocs.py -skip=5

#

#===------------------------------------------------------------------------===#

import argparse

import sys

_skip = 0

def PrintStack(line, stack):

  global _skip

  if _skip > 0:

    return

  print 'Unbalanced ' + line.rstrip();

  for l in stack:

    print l.rstrip()

def ProcessStack(line, f):

  stack = []

  while line and line.startswith('    #'):

    stack += [line]

    line = f.readline()

  return line, stack

def ProcessFree(line, f, allocs):

  if not line.startswith('FREE['):

    return f.readline()

  addr = int(line.split()[1], 16)

  next_line, stack = ProcessStack(f.readline(), f)

  if addr in allocs:

    del allocs[addr]

  else:

    PrintStack(line, stack)

  return next_line

def ProcessMalloc(line, f, allocs):

  if not line.startswith('MALLOC['):

    return ProcessFree(line, f, allocs)

  addr = int(line.split()[1], 16)

  assert not addr in allocs

  next_line, stack = ProcessStack(f.readline(), f)

  allocs[addr] = (line, stack)

  return next_line

def ProcessRun(line, f):

  if not line.startswith('MallocFreeTracer: START'):

    return ProcessMalloc(line, f, {})

  allocs = {}

  print line.rstrip()

  line = f.readline()

  while line:

    if line.startswith('MallocFreeTracer: STOP'):

      global _skip

      _skip = _skip - 1

      for _, (l, s) in allocs.iteritems():

        PrintStack(l, s)

      print line.rstrip()

      return f.readline()

    line = ProcessMalloc(line, f, allocs)

  return line

def ProcessFile(f):

  line = f.readline()

  while line:

    line = ProcessRun(line, f);

def main(argv):

  parser = argparse.ArgumentParser()

  parser.add_argument('--skip', default=0, help='number of runs to ignore')

  args = parser.parse_args()

  global _skip

  _skip = int(args.skip) + 1

  ProcessFile(sys.stdin)

if __name__ == '__main__':

  main(sys.argv)

// FIXME: This test infinite loops on darwin because it crashes

// printing a stack trace repeatedly

UNSUPPORTED: darwin

// Verifies lib/fuzzer/scripts/unbalanced_allocs.py script

RUN: %cpp_compiler %S/TraceMallocTest.cpp -o %t-TraceMallocTest

RUN: %t-TraceMallocTest -seed=1 -trace_malloc=1 -runs=100 2>&1 | \

RUN:    %libfuzzer_src/scripts/unbalanced_allocs.py --skip=5 | FileCheck %s

RUN: %t-TraceMallocTest -seed=1 -trace_malloc=2 -runs=100 2>&1 | \

RUN:    %libfuzzer_src/scripts/unbalanced_allocs.py --skip=5 | FileCheck %s --check-prefixes=CHECK,CHECK2

CHECK: MallocFreeTracer: START

CHECK: Unbalanced MALLOC[{{[0-9]+}}] [[PTR:0x[0-9a-f]+]] 4

CHECK2-NEXT: {{ #0 0x[0-9a-f]+ in }}

CHECK2-NEXT: {{ #1 0x[0-9a-f]+ in }}

CHECK2-NEXT: {{ #2 0x[0-9a-f]+ in }}

CHECK: MallocFreeTracer: STOP

CHECK: MallocFreeTracer: START

CHECK: Unbalanced FREE[{{[0-9]+}}] [[PTR]]

CHECK2-NEXT: {{ #0 0x[0-9a-f]+ in }}

CHECK2-NEXT: {{ #1 0x[0-9a-f]+ in }}

CHECK2-NEXT: {{ #2 0x[0-9a-f]+ in }}

CHECK: MallocFreeTracer: STOP