xref: /llvm-project/clang/utils/analyzer/exploded-graph-rewriter.py (revision 2ca5355712fc6b7ad95f8ce9b8e2054b621cda9b)
1#!/usr/bin/env python
2#
3#===- exploded-graph-rewriter.py - ExplodedGraph dump tool -----*- python -*--#
4#
5# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
6# See https://llvm.org/LICENSE.txt for license information.
7# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
8#
9#===-----------------------------------------------------------------------===#
10
11
12from __future__ import print_function
13
14import argparse
15import collections
16import json
17import logging
18import re
19
20
21# A helper function for finding the difference between two dictionaries.
22def diff_dicts(curr, prev):
23    removed = [k for k in prev if k not in curr or curr[k] != prev[k]]
24    added = [k for k in curr if k not in prev or curr[k] != prev[k]]
25    return (removed, added)
26
27
28# Represents any program state trait that is a dictionary of key-value pairs.
29class GenericMap(object):
30    def __init__(self, items):
31        self.generic_map = collections.OrderedDict(items)
32
33    def diff(self, prev):
34        return diff_dicts(self.generic_map, prev.generic_map)
35
36    def is_different(self, prev):
37        removed, added = self.diff(prev)
38        return len(removed) != 0 or len(added) != 0
39
40
41# A deserialized source location.
42class SourceLocation(object):
43    def __init__(self, json_loc):
44        super(SourceLocation, self).__init__()
45        self.line = json_loc['line']
46        self.col = json_loc['column']
47        self.filename = json_loc['filename'] \
48            if 'filename' in json_loc else '(main file)'
49
50
51# A deserialized program point.
52class ProgramPoint(object):
53    def __init__(self, json_pp):
54        super(ProgramPoint, self).__init__()
55        self.kind = json_pp['kind']
56        self.tag = json_pp['tag']
57        if self.kind == 'Edge':
58            self.src_id = json_pp['src_id']
59            self.dst_id = json_pp['dst_id']
60        elif self.kind == 'Statement':
61            self.stmt_kind = json_pp['stmt_kind']
62            self.stmt_point_kind = json_pp['stmt_point_kind']
63            self.pointer = json_pp['pointer']
64            self.pretty = json_pp['pretty']
65            self.loc = SourceLocation(json_pp['location']) \
66                if json_pp['location'] is not None else None
67        elif self.kind == 'BlockEntrance':
68            self.block_id = json_pp['block_id']
69
70
71# A single expression acting as a key in a deserialized Environment.
72class EnvironmentBindingKey(object):
73    def __init__(self, json_ek):
74        super(EnvironmentBindingKey, self).__init__()
75        # CXXCtorInitializer is not a Stmt!
76        self.stmt_id = json_ek['stmt_id'] if 'stmt_id' in json_ek \
77            else json_ek['init_id']
78        self.pretty = json_ek['pretty']
79        self.kind = json_ek['kind'] if 'kind' in json_ek else None
80
81    def _key(self):
82        return self.stmt_id
83
84    def __eq__(self, other):
85        return self._key() == other._key()
86
87    def __hash__(self):
88        return hash(self._key())
89
90
91# Deserialized description of a location context.
92class LocationContext(object):
93    def __init__(self, json_frame):
94        super(LocationContext, self).__init__()
95        self.lctx_id = json_frame['lctx_id']
96        self.caption = json_frame['location_context']
97        self.decl = json_frame['calling']
98        self.line = json_frame['call_line']
99
100    def _key(self):
101        return self.lctx_id
102
103    def __eq__(self, other):
104        return self._key() == other._key()
105
106    def __hash__(self):
107        return hash(self._key())
108
109
110# A group of deserialized Environment bindings that correspond to a specific
111# location context.
112class EnvironmentFrame(object):
113    def __init__(self, json_frame):
114        super(EnvironmentFrame, self).__init__()
115        self.location_context = LocationContext(json_frame)
116        self.bindings = collections.OrderedDict(
117            [(EnvironmentBindingKey(b),
118              b['value']) for b in json_frame['items']]
119            if json_frame['items'] is not None else [])
120
121    def diff_bindings(self, prev):
122        return diff_dicts(self.bindings, prev.bindings)
123
124    def is_different(self, prev):
125        removed, added = self.diff_bindings(prev)
126        return len(removed) != 0 or len(added) != 0
127
128
129# A deserialized Environment. This class can also hold other entities that
130# are similar to Environment, such as Objects Under Construction.
131class GenericEnvironment(object):
132    def __init__(self, json_e):
133        super(GenericEnvironment, self).__init__()
134        self.frames = [EnvironmentFrame(f) for f in json_e]
135
136    def diff_frames(self, prev):
137        # TODO: It's difficult to display a good diff when frame numbers shift.
138        if len(self.frames) != len(prev.frames):
139            return None
140
141        updated = []
142        for i in range(len(self.frames)):
143            f = self.frames[i]
144            prev_f = prev.frames[i]
145            if f.location_context == prev_f.location_context:
146                if f.is_different(prev_f):
147                    updated.append(i)
148            else:
149                # We have the whole frame replaced with another frame.
150                # TODO: Produce a nice diff.
151                return None
152
153        # TODO: Add support for added/removed.
154        return updated
155
156    def is_different(self, prev):
157        updated = self.diff_frames(prev)
158        return updated is None or len(updated) > 0
159
160
161# A single binding key in a deserialized RegionStore cluster.
162class StoreBindingKey(object):
163    def __init__(self, json_sk):
164        super(StoreBindingKey, self).__init__()
165        self.kind = json_sk['kind']
166        self.offset = json_sk['offset']
167
168    def _key(self):
169        return (self.kind, self.offset)
170
171    def __eq__(self, other):
172        return self._key() == other._key()
173
174    def __hash__(self):
175        return hash(self._key())
176
177
178# A single cluster of the deserialized RegionStore.
179class StoreCluster(object):
180    def __init__(self, json_sc):
181        super(StoreCluster, self).__init__()
182        self.base_region = json_sc['cluster']
183        self.bindings = collections.OrderedDict(
184            [(StoreBindingKey(b), b['value']) for b in json_sc['items']])
185
186    def diff_bindings(self, prev):
187        return diff_dicts(self.bindings, prev.bindings)
188
189    def is_different(self, prev):
190        removed, added = self.diff_bindings(prev)
191        return len(removed) != 0 or len(added) != 0
192
193
194# A deserialized RegionStore.
195class Store(object):
196    def __init__(self, json_s):
197        super(Store, self).__init__()
198        self.ptr = json_s['pointer']
199        self.clusters = collections.OrderedDict(
200            [(c['pointer'], StoreCluster(c)) for c in json_s['items']])
201
202    def diff_clusters(self, prev):
203        removed = [k for k in prev.clusters if k not in self.clusters]
204        added = [k for k in self.clusters if k not in prev.clusters]
205        updated = [k for k in prev.clusters if k in self.clusters
206                   and prev.clusters[k].is_different(self.clusters[k])]
207        return (removed, added, updated)
208
209    def is_different(self, prev):
210        removed, added, updated = self.diff_clusters(prev)
211        return len(removed) != 0 or len(added) != 0 or len(updated) != 0
212
213
214# A deserialized program state.
215class ProgramState(object):
216    def __init__(self, state_id, json_ps):
217        super(ProgramState, self).__init__()
218        logging.debug('Adding ProgramState ' + str(state_id))
219
220        self.state_id = state_id
221
222        self.store = Store(json_ps['store']) \
223            if json_ps['store'] is not None else None
224
225        self.environment = \
226            GenericEnvironment(json_ps['environment']['items']) \
227            if json_ps['environment'] is not None else None
228
229        self.constraints = GenericMap([
230            (c['symbol'], c['range']) for c in json_ps['constraints']
231        ]) if json_ps['constraints'] is not None else None
232
233        self.dynamic_types = GenericMap([
234                (t['region'], '%s%s' % (t['dyn_type'],
235                                        ' (or a sub-class)'
236                                        if t['sub_classable'] else ''))
237                for t in json_ps['dynamic_types']]) \
238            if json_ps['dynamic_types'] is not None else None
239
240        self.constructing_objects = \
241            GenericEnvironment(json_ps['constructing_objects']) \
242            if json_ps['constructing_objects'] is not None else None
243
244        # TODO: Checker messages.
245
246
247# A deserialized exploded graph node. Has a default constructor because it
248# may be referenced as part of an edge before its contents are deserialized,
249# and in this moment we already need a room for predecessors and successors.
250class ExplodedNode(object):
251    def __init__(self):
252        super(ExplodedNode, self).__init__()
253        self.predecessors = []
254        self.successors = []
255
256    def construct(self, node_id, json_node):
257        logging.debug('Adding ' + node_id)
258        self.node_id = json_node['node_id']
259        self.ptr = json_node['pointer']
260        self.points = [ProgramPoint(p) for p in json_node['program_points']]
261        self.state = ProgramState(json_node['state_id'],
262                                  json_node['program_state']) \
263            if json_node['program_state'] is not None else None
264
265        assert self.node_name() == node_id
266
267    def node_name(self):
268        return 'Node' + self.ptr
269
270
271# A deserialized ExplodedGraph. Constructed by consuming a .dot file
272# line-by-line.
273class ExplodedGraph(object):
274    # Parse .dot files with regular expressions.
275    node_re = re.compile(
276        '^(Node0x[0-9a-f]*) \\[shape=record,.*label="{(.*)\\\\l}"\\];$')
277    edge_re = re.compile(
278        '^(Node0x[0-9a-f]*) -> (Node0x[0-9a-f]*);$')
279
280    def __init__(self):
281        super(ExplodedGraph, self).__init__()
282        self.nodes = collections.defaultdict(ExplodedNode)
283        self.root_id = None
284        self.incomplete_line = ''
285
286    def add_raw_line(self, raw_line):
287        if raw_line.startswith('//'):
288            return
289
290        # Allow line breaks by waiting for ';'. This is not valid in
291        # a .dot file, but it is useful for writing tests.
292        if len(raw_line) > 0 and raw_line[-1] != ';':
293            self.incomplete_line += raw_line
294            return
295        raw_line = self.incomplete_line + raw_line
296        self.incomplete_line = ''
297
298        # Apply regexps one by one to see if it's a node or an edge
299        # and extract contents if necessary.
300        logging.debug('Line: ' + raw_line)
301        result = self.edge_re.match(raw_line)
302        if result is not None:
303            logging.debug('Classified as edge line.')
304            pred = result.group(1)
305            succ = result.group(2)
306            self.nodes[pred].successors.append(succ)
307            self.nodes[succ].predecessors.append(pred)
308            return
309        result = self.node_re.match(raw_line)
310        if result is not None:
311            logging.debug('Classified as node line.')
312            node_id = result.group(1)
313            if len(self.nodes) == 0:
314                self.root_id = node_id
315            # Note: when writing tests you don't need to escape everything,
316            # even though in a valid dot file everything is escaped.
317            node_label = result.group(2).replace('\\l', '') \
318                                        .replace(' ', '') \
319                                        .replace('\\"', '"') \
320                                        .replace('\\{', '{') \
321                                        .replace('\\}', '}') \
322                                        .replace('\\\\', '\\') \
323                                        .replace('\\|', '|') \
324                                        .replace('\\<', '\\\\<') \
325                                        .replace('\\>', '\\\\>') \
326                                        .rstrip(',')
327            logging.debug(node_label)
328            json_node = json.loads(node_label)
329            self.nodes[node_id].construct(node_id, json_node)
330            return
331        logging.debug('Skipping.')
332
333
334# A visitor that dumps the ExplodedGraph into a DOT file with fancy HTML-based
335# syntax highlighing.
336class DotDumpVisitor(object):
337    def __init__(self, do_diffs):
338        super(DotDumpVisitor, self).__init__()
339        self._do_diffs = do_diffs
340
341    @staticmethod
342    def _dump_raw(s):
343        print(s, end='')
344
345    @staticmethod
346    def _dump(s):
347        print(s.replace('&', '&amp;')
348               .replace('{', '\\{')
349               .replace('}', '\\}')
350               .replace('\\<', '&lt;')
351               .replace('\\>', '&gt;')
352               .replace('\\l', '<br />')
353               .replace('|', '\\|'), end='')
354
355    @staticmethod
356    def _diff_plus_minus(is_added):
357        if is_added is None:
358            return ''
359        if is_added:
360            return '<font color="forestgreen">+</font>'
361        return '<font color="red">-</font>'
362
363    def visit_begin_graph(self, graph):
364        self._graph = graph
365        self._dump_raw('digraph "ExplodedGraph" {\n')
366        self._dump_raw('label="";\n')
367
368    def visit_program_point(self, p):
369        if p.kind in ['Edge', 'BlockEntrance', 'BlockExit']:
370            color = 'gold3'
371        elif p.kind in ['PreStmtPurgeDeadSymbols',
372                        'PostStmtPurgeDeadSymbols']:
373            color = 'red'
374        elif p.kind in ['CallEnter', 'CallExitBegin', 'CallExitEnd']:
375            color = 'blue'
376        elif p.kind in ['Statement']:
377            color = 'cyan4'
378        else:
379            color = 'forestgreen'
380
381        if p.kind == 'Statement':
382            # This avoids pretty-printing huge statements such as CompoundStmt.
383            # Such statements show up only at [Pre|Post]StmtPurgeDeadSymbols
384            skip_pretty = 'PurgeDeadSymbols' in p.stmt_point_kind
385            stmt_color = 'cyan3'
386            if p.loc is not None:
387                self._dump('<tr><td align="left" width="0">'
388                           '%s:<b>%s</b>:<b>%s</b>:</td>'
389                           '<td align="left" width="0"><font color="%s">'
390                           '%s</font></td>'
391                           '<td align="left"><font color="%s">%s</font></td>'
392                           '<td>%s</td></tr>'
393                           % (p.loc.filename, p.loc.line,
394                              p.loc.col, color, p.stmt_kind,
395                              stmt_color, p.stmt_point_kind,
396                              p.pretty if not skip_pretty else ''))
397            else:
398                self._dump('<tr><td align="left" width="0">'
399                           '<i>Invalid Source Location</i>:</td>'
400                           '<td align="left" width="0">'
401                           '<font color="%s">%s</font></td>'
402                           '<td align="left"><font color="%s">%s</font></td>'
403                           '<td>%s</td></tr>'
404                           % (color, p.stmt_kind,
405                              stmt_color, p.stmt_point_kind,
406                              p.pretty if not skip_pretty else ''))
407        elif p.kind == 'Edge':
408            self._dump('<tr><td width="0"></td>'
409                       '<td align="left" width="0">'
410                       '<font color="%s">%s</font></td><td align="left">'
411                       '[B%d] -\\> [B%d]</td></tr>'
412                       % (color, 'BlockEdge', p.src_id, p.dst_id))
413        elif p.kind == 'BlockEntrance':
414            self._dump('<tr><td width="0"></td>'
415                       '<td align="left" width="0">'
416                       '<font color="%s">%s</font></td>'
417                       '<td align="left">[B%d]</td></tr>'
418                       % (color, p.kind, p.block_id))
419        else:
420            # TODO: Print more stuff for other kinds of points.
421            self._dump('<tr><td width="0"></td>'
422                       '<td align="left" width="0" colspan="2">'
423                       '<font color="%s">%s</font></td></tr>'
424                       % (color, p.kind))
425
426        if p.tag is not None:
427            self._dump('<tr><td width="0"></td>'
428                       '<td colspan="3" align="left">'
429                       '<b>Tag: </b> <font color="crimson">'
430                       '%s</font></td></tr>' % p.tag)
431
432    def visit_environment(self, e, prev_e=None):
433        self._dump('<table border="0">')
434
435        def dump_location_context(lc, is_added=None):
436            self._dump('<tr><td>%s</td>'
437                       '<td align="left"><b>%s</b></td>'
438                       '<td align="left" colspan="2">'
439                       '<font color="grey60">%s </font>'
440                       '%s</td></tr>'
441                       % (self._diff_plus_minus(is_added),
442                          lc.caption, lc.decl,
443                          ('(line %s)' % lc.line) if lc.line is not None
444                          else ''))
445
446        def dump_binding(f, b, is_added=None):
447            self._dump('<tr><td>%s</td>'
448                       '<td align="left"><i>S%s</i></td>'
449                       '%s'
450                       '<td align="left">%s</td>'
451                       '<td align="left">%s</td></tr>'
452                       % (self._diff_plus_minus(is_added),
453                          b.stmt_id,
454                          '<td align="left"><font color="darkgreen"><i>'
455                          '(%s)</i></font></td>' % b.kind
456                          if b.kind is not None else '',
457                          b.pretty, f.bindings[b]))
458
459        frames_updated = e.diff_frames(prev_e) if prev_e is not None else None
460        if frames_updated:
461            for i in frames_updated:
462                f = e.frames[i]
463                prev_f = prev_e.frames[i]
464                dump_location_context(f.location_context)
465                bindings_removed, bindings_added = f.diff_bindings(prev_f)
466                for b in bindings_removed:
467                    dump_binding(prev_f, b, False)
468                for b in bindings_added:
469                    dump_binding(f, b, True)
470        else:
471            for f in e.frames:
472                dump_location_context(f.location_context)
473                for b in f.bindings:
474                    dump_binding(f, b)
475
476        self._dump('</table>')
477
478    def visit_environment_in_state(self, selector, title, s, prev_s=None):
479        e = getattr(s, selector)
480        prev_e = getattr(prev_s, selector) if prev_s is not None else None
481        if e is None and prev_e is None:
482            return
483
484        self._dump('<hr /><tr><td align="left"><b>%s: </b>' % title)
485        if e is None:
486            self._dump('<i> Nothing!</i>')
487        else:
488            if prev_e is not None:
489                if e.is_different(prev_e):
490                    self._dump('</td></tr><tr><td align="left">')
491                    self.visit_environment(e, prev_e)
492                else:
493                    self._dump('<i> No changes!</i>')
494            else:
495                self._dump('</td></tr><tr><td align="left">')
496                self.visit_environment(e)
497
498        self._dump('</td></tr>')
499
500    def visit_store(self, s, prev_s=None):
501        self._dump('<table border="0">')
502
503        def dump_binding(s, c, b, is_added=None):
504            self._dump('<tr><td>%s</td>'
505                       '<td align="left">%s</td>'
506                       '<td align="left">%s</td>'
507                       '<td align="left">%s</td>'
508                       '<td align="left">%s</td></tr>'
509                       % (self._diff_plus_minus(is_added),
510                          s.clusters[c].base_region, b.offset,
511                          '(<i>Default</i>)' if b.kind == 'Default'
512                          else '',
513                          s.clusters[c].bindings[b]))
514
515        if prev_s is not None:
516            clusters_removed, clusters_added, clusters_updated = \
517                s.diff_clusters(prev_s)
518            for c in clusters_removed:
519                for b in prev_s.clusters[c].bindings:
520                    dump_binding(prev_s, c, b, False)
521            for c in clusters_updated:
522                bindings_removed, bindings_added = \
523                    s.clusters[c].diff_bindings(prev_s.clusters[c])
524                for b in bindings_removed:
525                    dump_binding(prev_s, c, b, False)
526                for b in bindings_added:
527                    dump_binding(s, c, b, True)
528            for c in clusters_added:
529                for b in s.clusters[c].bindings:
530                    dump_binding(s, c, b, True)
531        else:
532            for c in s.clusters:
533                for b in s.clusters[c].bindings:
534                    dump_binding(s, c, b)
535
536        self._dump('</table>')
537
538    def visit_store_in_state(self, s, prev_s=None):
539        st = s.store
540        prev_st = prev_s.store if prev_s is not None else None
541        if st is None and prev_st is None:
542            return
543
544        self._dump('<hr /><tr><td align="left"><b>Store: </b>')
545        if st is None:
546            self._dump('<i> Nothing!</i>')
547        else:
548            if prev_st is not None:
549                if s.store.is_different(prev_st):
550                    self._dump('</td></tr><tr><td align="left">')
551                    self.visit_store(st, prev_st)
552                else:
553                    self._dump('<i> No changes!</i>')
554            else:
555                self._dump('</td></tr><tr><td align="left">')
556                self.visit_store(st)
557        self._dump('</td></tr>')
558
559    def visit_generic_map(self, m, prev_m=None):
560        self._dump('<table border="0">')
561
562        def dump_pair(m, k, is_added=None):
563            self._dump('<tr><td>%s</td>'
564                       '<td align="left">%s</td>'
565                       '<td align="left">%s</td></tr>'
566                       % (self._diff_plus_minus(is_added),
567                          k, m.generic_map[k]))
568
569        if prev_m is not None:
570            removed, added = m.diff(prev_m)
571            for k in removed:
572                dump_pair(prev_m, k, False)
573            for k in added:
574                dump_pair(m, k, True)
575        else:
576            for k in m.generic_map:
577                dump_pair(m, k, None)
578
579        self._dump('</table>')
580
581    def visit_generic_map_in_state(self, selector, title, s, prev_s=None):
582        m = getattr(s, selector)
583        prev_m = getattr(prev_s, selector) if prev_s is not None else None
584        if m is None and prev_m is None:
585            return
586
587        self._dump('<hr />')
588        self._dump('<tr><td align="left">'
589                   '<b>%s: </b>' % title)
590        if m is None:
591            self._dump('<i> Nothing!</i>')
592        else:
593            if prev_s is not None:
594                if prev_m is not None:
595                    if m.is_different(prev_m):
596                        self._dump('</td></tr><tr><td align="left">')
597                        self.visit_generic_map(m, prev_m)
598                    else:
599                        self._dump('<i> No changes!</i>')
600            if prev_m is None:
601                self._dump('</td></tr><tr><td align="left">')
602                self.visit_generic_map(m)
603        self._dump('</td></tr>')
604
605    def visit_state(self, s, prev_s):
606        self.visit_store_in_state(s, prev_s)
607        self.visit_environment_in_state('environment', 'Environment',
608                                        s, prev_s)
609        self.visit_generic_map_in_state('constraints', 'Ranges',
610                                        s, prev_s)
611        self.visit_generic_map_in_state('dynamic_types', 'Dynamic Types',
612                                        s, prev_s)
613        self.visit_environment_in_state('constructing_objects',
614                                        'Objects Under Construction',
615                                        s, prev_s)
616
617    def visit_node(self, node):
618        self._dump('%s [shape=record,label=<<table border="0">'
619                   % (node.node_name()))
620
621        self._dump('<tr><td bgcolor="grey"><b>Node %d (%s) - '
622                   'State %s</b></td></tr>'
623                   % (node.node_id, node.ptr, node.state.state_id
624                      if node.state is not None else 'Unspecified'))
625        self._dump('<tr><td align="left" width="0">')
626        if len(node.points) > 1:
627            self._dump('<b>Program points:</b></td></tr>')
628        else:
629            self._dump('<b>Program point:</b></td></tr>')
630        self._dump('<tr><td align="left" width="0">'
631                   '<table border="0" align="left" width="0">')
632        for p in node.points:
633            self.visit_program_point(p)
634        self._dump('</table></td></tr>')
635
636        if node.state is not None:
637            prev_s = None
638            # Do diffs only when we have a unique predecessor.
639            # Don't do diffs on the leaf nodes because they're
640            # the important ones.
641            if self._do_diffs and len(node.predecessors) == 1 \
642               and len(node.successors) > 0:
643                prev_s = self._graph.nodes[node.predecessors[0]].state
644            self.visit_state(node.state, prev_s)
645        self._dump_raw('</table>>];\n')
646
647    def visit_edge(self, pred, succ):
648        self._dump_raw('%s -> %s;\n' % (pred.node_name(), succ.node_name()))
649
650    def visit_end_of_graph(self):
651        self._dump_raw('}\n')
652
653
654# A class that encapsulates traversal of the ExplodedGraph. Different explorer
655# kinds could potentially traverse specific sub-graphs.
656class Explorer(object):
657    def __init__(self):
658        super(Explorer, self).__init__()
659
660    def explore(self, graph, visitor):
661        visitor.visit_begin_graph(graph)
662        for node in sorted(graph.nodes):
663            logging.debug('Visiting ' + node)
664            visitor.visit_node(graph.nodes[node])
665            for succ in sorted(graph.nodes[node].successors):
666                logging.debug('Visiting edge: %s -> %s ' % (node, succ))
667                visitor.visit_edge(graph.nodes[node], graph.nodes[succ])
668        visitor.visit_end_of_graph()
669
670
671def main():
672    parser = argparse.ArgumentParser()
673    parser.add_argument('filename', type=str)
674    parser.add_argument('-v', '--verbose', action='store_const',
675                        dest='loglevel', const=logging.DEBUG,
676                        default=logging.WARNING,
677                        help='enable info prints')
678    parser.add_argument('-d', '--diff', action='store_const', dest='diff',
679                        const=True, default=False,
680                        help='display differences between states')
681    args = parser.parse_args()
682    logging.basicConfig(level=args.loglevel)
683
684    graph = ExplodedGraph()
685    with open(args.filename) as fd:
686        for raw_line in fd:
687            raw_line = raw_line.strip()
688            graph.add_raw_line(raw_line)
689
690    explorer = Explorer()
691    visitor = DotDumpVisitor(args.diff)
692    explorer.explore(graph, visitor)
693
694
695if __name__ == '__main__':
696    main()
697