#! /usr/bin/env python
# To use:
# 1) Update the 'decls' list below with your fuzzing configuration.
# 2) Run with the clang binary as the command-line argument.
import random
import subprocess
import sys
import os
clang = sys.argv[1]
none_opts = 0.3
class Decl:
def __init__(self, text, depends=[], provides=[], conflicts=[]):
self.text = text
self.depends = depends
self.provides = provides
self.conflicts = conflicts
def valid(self, model):
for i in self.depends:
if i not in model.decls:
return False
for i in self.conflicts:
if i in model.decls:
return False
return True
def apply(self, model, name):
for i in self.provides:
model.decls[i] = True
model.source += self.text % {'name': name}
decls = [
Decl('struct X { int n; };\n', provides=['X'], conflicts=['X']),
Decl('static_assert(X{.n=1}.n == 1, "");\n', depends=['X']),
Decl('X %(name)s;\n', depends=['X']),
]
class FS:
def __init__(self):
self.fs = {}
self.prevfs = {}
def write(self, path, contents):
self.fs[path] = contents
def done(self):
for f, s in self.fs.items():
if self.prevfs.get(f) != s:
f = file(f, 'w')
f.write(s)
f.close()
for f in self.prevfs:
if f not in self.fs:
os.remove(f)
self.prevfs, self.fs = self.fs, {}
fs = FS()
class CodeModel:
def __init__(self):
self.source = ''
self.modules = {}
self.decls = {}
self.i = 0
def make_name(self):
self.i += 1
return 'n' + str(self.i)
def fails(self):
fs.write('module.modulemap',
''.join('module %s { header "%s.h" export * }\n' % (m, m)
for m in self.modules.keys()))
for m, (s, _) in self.modules.items():
fs.write('%s.h' % m, s)
fs.write('main.cc', self.source)
fs.done()
return subprocess.call([clang, '-std=c++11', '-c', '-fmodules', 'main.cc', '-o', '/dev/null']) != 0
def generate():
model = CodeModel()
m = []
try:
for d in mutations(model):
d(model)
m.append(d)
if not model.fails():
return
except KeyboardInterrupt:
print
return True
sys.stdout.write('\nReducing:\n')
sys.stdout.flush()
try:
while True:
assert m, 'got a failure with no steps; broken clang binary?'
i = random.choice(range(len(m)))
x = m[0:i] + m[i+1:]
m2 = CodeModel()
for d in x:
d(m2)
if m2.fails():
m = x
model = m2
else:
sys.stdout.write('.')
sys.stdout.flush()
except KeyboardInterrupt:
# FIXME: Clean out output directory first.
model.fails()
return model
def choose(options):
while True:
i = int(random.uniform(0, len(options) + none_opts))
if i >= len(options):
break
yield options[i]
def mutations(model):
options = [create_module, add_top_level_decl]
for opt in choose(options):
yield opt(model, options)
def create_module(model, options):
n = model.make_name()
def go(model):
model.modules[n] = (model.source, model.decls)
(model.source, model.decls) = ('', {})
options += [lambda model, options: add_import(model, options, n)]
return go
def add_top_level_decl(model, options):
n = model.make_name()
d = random.choice([decl for decl in decls if decl.valid(model)])
def go(model):
if not d.valid(model):
return
d.apply(model, n)
return go
def add_import(model, options, module_name):
def go(model):
if module_name in model.modules:
model.source += '#include "%s.h"\n' % module_name
model.decls.update(model.modules[module_name][1])
return go
sys.stdout.write('Finding bug: ')
while True:
if generate():
break
sys.stdout.write('.')
sys.stdout.flush()
