aboutsummaryrefslogblamecommitdiffstats
path: root/lib/dialyzer/src/dialyzer_callgraph.erl
blob: 1f79e164492d7f0bb37d20d1754c2a68516b6992 (plain) (tree)
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700




























                                                                         

                     


























                                                                           

                                                        








































                                                                               

                                                                         




















































































































































































































































































































































































































































































































































































































                                                                                       











                                                                                
%% -*- erlang-indent-level: 2 -*-
%%-----------------------------------------------------------------------
%% %CopyrightBegin%
%% 
%% Copyright Ericsson AB 2006-2009. All Rights Reserved.
%% 
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%% 
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%% 
%% %CopyrightEnd%
%%

%%%-------------------------------------------------------------------
%%% File    : dialyzer_callgraph.erl
%%% Author  : Tobias Lindahl <[email protected]>
%%% Description : 
%%%
%%% Created : 30 Mar 2005 by Tobias Lindahl <[email protected]>
%%%-------------------------------------------------------------------
-module(dialyzer_callgraph).

-export([add_edges/2,
	 all_nodes/1,
	 delete/1,
	 finalize/1,
	 is_escaping/2,
	 is_self_rec/2,
	 non_local_calls/1,
	 lookup_rec_var/2,
	 lookup_call_site/2,
	 lookup_label/2,
	 lookup_name/2,
	 modules/1,
	 module_deps/1,
	 %% module_postorder/1,
	 module_postorder_from_funs/2,
	 new/0,
	 in_neighbours/2,
	 renew_race_info/4,
	 reset_from_funs/2,
	 scan_core_tree/2,
	 strip_module_deps/2,
	 take_scc/1,
	 remove_external/1,
	 to_dot/2,
	 to_ps/3]).

-export([cleanup/1, get_digraph/1, get_named_tables/1, get_public_tables/1,
         get_race_code/1, get_race_detection/1, race_code_new/1,
         put_race_code/2, put_race_detection/2, put_named_tables/2,
         put_public_tables/2, put_behaviour_api_calls/2,
	 get_behaviour_api_calls/1]).

-include("dialyzer.hrl").

%%----------------------------------------------------------------------

-type mfa_or_funlbl() :: label() | mfa().
-type scc()	      :: [mfa_or_funlbl()].
-type mfa_calls()     :: [{mfa_or_funlbl(), mfa_or_funlbl()}].

%%-----------------------------------------------------------------------------
%% A callgraph is a directed graph where the nodes are functions and a
%% call between two functions is an edge from the caller to the callee.
%% 
%% calls	-  A mapping from call site (and apply site) labels
%%		   to the possible functions that can be called.
%% digraph	-  A digraph representing the callgraph. 
%%		   Nodes are represented as MFAs or labels.
%% esc		-  A set of all escaping functions as reported by dialyzer_dep.
%% postorder	-  A list of strongly connected components of the callgraph
%%		   sorted in a topological bottom-up order.
%%		   This is produced by calling finalize/1.
%% name_map	-  A mapping from label to MFA.
%% rev_name_map	-  A reverse mapping of the name_map.
%% rec_var_map	-  A dict mapping from letrec bound labels to function names.
%%		   Only for top level functions (from module defs).
%% self_rec	-  A set containing all self recursive functions.
%%		   Note that this contains MFAs for named functions and labels
%%		   whenever applicable.
%%-----------------------------------------------------------------------------

-record(callgraph, {digraph        = digraph:new() :: digraph(),
                    esc	           = sets:new()    :: set(),
                    name_map	   = dict:new()    :: dict(),
                    rev_name_map   = dict:new()    :: dict(),
                    postorder      = []	           :: [scc()],
                    rec_var_map    = dict:new()    :: dict(),
                    self_rec	   = sets:new()    :: set(),
                    calls          = dict:new()    :: dict(),
                    race_code      = dict:new()    :: dict(),
                    public_tables  = []            :: [label()],
                    named_tables   = []            :: [string()],
                    race_detection = false         :: boolean(),
		    beh_api_calls  = []            :: [{mfa(), mfa()}]}).

%% Exported Types

-type callgraph() :: #callgraph{}.

%%----------------------------------------------------------------------

-spec new() -> callgraph().

new() ->
  #callgraph{}.

-spec delete(callgraph()) -> 'true'.

delete(#callgraph{digraph = Digraph}) ->
  digraph_delete(Digraph).

-spec all_nodes(callgraph()) -> [mfa()].

all_nodes(#callgraph{digraph = DG}) ->
  digraph_vertices(DG).

-spec lookup_rec_var(label(), callgraph()) -> 'error' | {'ok', mfa()}.

lookup_rec_var(Label, #callgraph{rec_var_map = RecVarMap}) 
  when is_integer(Label) ->
  dict:find(Label, RecVarMap).

-spec lookup_call_site(label(), callgraph()) -> 'error' | {'ok', [_]}. % XXX: refine

lookup_call_site(Label, #callgraph{calls = Calls})
  when is_integer(Label) ->
  dict:find(Label, Calls).

-spec lookup_name(label(), callgraph()) -> 'error' | {'ok', mfa()}.

lookup_name(Label, #callgraph{name_map = NameMap})
  when is_integer(Label) ->
  dict:find(Label, NameMap).

-spec lookup_label(mfa_or_funlbl(), callgraph()) -> 'error' | {'ok', integer()}.

lookup_label({_,_,_} = MFA, #callgraph{rev_name_map = RevNameMap}) ->
  dict:find(MFA, RevNameMap);
lookup_label(Label, #callgraph{}) when is_integer(Label) ->
  {ok, Label}.

-spec in_neighbours(mfa_or_funlbl(), callgraph()) -> 'none' | [mfa_or_funlbl(),...].

in_neighbours(Label, #callgraph{digraph = Digraph, name_map = NameMap})
  when is_integer(Label) ->
  Name = case dict:find(Label, NameMap) of
	   {ok, Val} -> Val;
	   error -> Label
	 end,
  digraph_in_neighbours(Name, Digraph);
in_neighbours({_, _, _} = MFA, #callgraph{digraph = Digraph}) ->
  digraph_in_neighbours(MFA, Digraph).

-spec is_self_rec(mfa_or_funlbl(), callgraph()) -> boolean().

is_self_rec(MfaOrLabel, #callgraph{self_rec = SelfRecs}) ->
  sets:is_element(MfaOrLabel, SelfRecs).

-spec is_escaping(label(), callgraph()) -> boolean().

is_escaping(Label, #callgraph{esc = Esc}) when is_integer(Label) ->
  sets:is_element(Label, Esc).  

-type callgraph_edge() :: {mfa_or_funlbl(),mfa_or_funlbl()}.
-spec add_edges([callgraph_edge()], callgraph()) -> callgraph().

add_edges([], CG) ->
  CG;
add_edges(Edges, #callgraph{digraph = Callgraph} = CG) ->
  CG#callgraph{digraph = digraph_add_edges(Edges, Callgraph)}.

-spec add_edges([callgraph_edge()], [mfa_or_funlbl()], callgraph()) -> callgraph().

add_edges(Edges, MFAs, #callgraph{digraph = DG} = CG) ->
  DG1 = digraph_confirm_vertices(MFAs, DG),
  add_edges(Edges, CG#callgraph{digraph = DG1}).

-spec take_scc(callgraph()) -> 'none' | {'ok', scc(), callgraph()}.

take_scc(#callgraph{postorder = [SCC|SCCs]} = CG) ->
  {ok, SCC, CG#callgraph{postorder = SCCs}};
take_scc(#callgraph{postorder = []}) ->
  none.

-spec remove_external(callgraph()) -> {callgraph(), [tuple()]}.

remove_external(#callgraph{digraph = DG} = CG) ->
  {NewDG, External} = digraph_remove_external(DG),
  {CG#callgraph{digraph = NewDG}, External}.

-spec non_local_calls(callgraph()) -> mfa_calls().

non_local_calls(#callgraph{digraph = DG}) ->
  Edges = digraph_edges(DG),
  find_non_local_calls(Edges, sets:new()).

-spec find_non_local_calls([{mfa_or_funlbl(), mfa_or_funlbl()}], set()) -> mfa_calls().

find_non_local_calls([{{M,_,_}, {M,_,_}}|Left], Set) ->
  find_non_local_calls(Left, Set);
find_non_local_calls([{{M1,_,_}, {M2,_,_}} = Edge|Left], Set) when M1 =/= M2 ->
  find_non_local_calls(Left, sets:add_element(Edge, Set));
find_non_local_calls([{{_,_,_}, Label}|Left], Set) when is_integer(Label) ->
  find_non_local_calls(Left, Set);  
find_non_local_calls([{Label, {_,_,_}}|Left], Set) when is_integer(Label) ->
  find_non_local_calls(Left, Set);
find_non_local_calls([{Label1, Label2}|Left], Set) when is_integer(Label1),
							is_integer(Label2) ->
  find_non_local_calls(Left, Set);
find_non_local_calls([], Set) ->
  sets:to_list(Set).

-spec renew_race_info(callgraph(), dict(), [label()], [string()]) ->
        callgraph().

renew_race_info(CG, RaceCode, PublicTables, NamedTables) ->
  CG#callgraph{race_code = RaceCode,
               public_tables = PublicTables,
               named_tables = NamedTables}.

%%----------------------------------------------------------------------
%% Handling of modules & SCCs
%%----------------------------------------------------------------------

-spec modules(callgraph()) -> [module()].

modules(#callgraph{digraph = DG}) ->
  ordsets:from_list([M || {M,_F,_A} <- digraph_vertices(DG)]).

-spec module_postorder(callgraph()) -> [[module()]].

module_postorder(#callgraph{digraph = DG}) ->
  Edges = digraph_edges(DG),
  Nodes = ordsets:from_list([M || {M,_F,_A} <- digraph_vertices(DG)]),
  MDG = digraph:new(),
  MDG1 = digraph_confirm_vertices(Nodes, MDG),
  MDG2 = create_module_digraph(Edges, MDG1),
  MDG3 = digraph_utils:condensation(MDG2),
  PostOrder = digraph_utils:postorder(MDG3),
  PostOrder1 = sort_sccs_internally(PostOrder, MDG2),
  digraph:delete(MDG2),
  digraph_delete(MDG3),
  PostOrder1.

%% The module deps of a module are modules that depend on the module
-spec module_deps(callgraph()) -> dict().

module_deps(#callgraph{digraph = DG}) ->
  Edges = digraph_edges(DG),
  Nodes = ordsets:from_list([M || {M,_F,_A} <- digraph_vertices(DG)]),
  MDG = digraph:new(),
  MDG1 = digraph_confirm_vertices(Nodes, MDG),
  MDG2 = create_module_digraph(Edges, MDG1),
  Deps = [{N, ordsets:from_list(digraph:in_neighbours(MDG2, N))}
	  || N <- Nodes],
  digraph_delete(MDG2),
  dict:from_list(Deps).

-spec strip_module_deps(dict(), set()) -> dict().

strip_module_deps(ModDeps, StripSet) ->
  FilterFun1 = fun(Val) -> not sets:is_element(Val, StripSet) end,
  MapFun = fun(_Key, ValSet) -> ordsets:filter(FilterFun1, ValSet) end,
  ModDeps1 = dict:map(MapFun, ModDeps),
  FilterFun2 = fun(_Key, ValSet) -> ValSet =/= [] end,
  dict:filter(FilterFun2, ModDeps1).

sort_sccs_internally(PO, MDG) ->
  sort_sccs_internally(PO, MDG, []).

sort_sccs_internally([SCC|SCCs], MDG, Acc) ->
  case SCC of
    [_, _, _ | _] ->    % length(SCC) >= 3
      TmpDG = digraph_utils:subgraph(MDG, SCC),
      NewSCC = digraph_utils:postorder(TmpDG),
      digraph_delete(TmpDG),
      sort_sccs_internally(SCCs, MDG, [NewSCC|Acc]);
    _ ->
      sort_sccs_internally(SCCs, MDG, [SCC|Acc])
  end;
sort_sccs_internally([], _MDG, Acc) ->
  lists:reverse(Acc).

create_module_digraph([{{M, _, _}, {M, _, _}}|Left], MDG) ->
  create_module_digraph(Left, MDG);
create_module_digraph([{{M1, _, _}, {M2, _, _}}|Left], MDG) ->
  create_module_digraph(Left, digraph_add_edge(M1, M2, MDG));
create_module_digraph([{_, _}|Left], MDG) ->
  create_module_digraph(Left, MDG);
create_module_digraph([], MDG) ->
  MDG.

-spec finalize(callgraph()) -> callgraph().

finalize(#callgraph{digraph = DG} = CG) ->
  CG#callgraph{postorder = digraph_finalize(DG)}.

-spec reset_from_funs([mfa_or_funlbl()], callgraph()) -> callgraph().

reset_from_funs(Funs, #callgraph{digraph = DG} = CG) ->
  SubGraph = digraph_reaching_subgraph(Funs, DG),
  Postorder = digraph_finalize(SubGraph),
  digraph_delete(SubGraph),
  CG#callgraph{postorder = Postorder}.

-spec module_postorder_from_funs([mfa_or_funlbl()], callgraph()) -> [[module()]].

module_postorder_from_funs(Funs, #callgraph{digraph = DG} = CG) ->
  SubGraph = digraph_reaching_subgraph(Funs, DG),
  PO = module_postorder(CG#callgraph{digraph = SubGraph}),
  digraph_delete(SubGraph),
  PO.
  
%%----------------------------------------------------------------------
%% Core code
%%----------------------------------------------------------------------

%% The core tree must be labeled as by cerl_trees:label/1 (or /2).
%% The set of labels in the tree must be disjoint from the set of
%% labels already occuring in the callgraph.

-spec scan_core_tree(cerl:c_module(), callgraph()) -> callgraph().

scan_core_tree(Tree, #callgraph{calls = OldCalls,
				esc = OldEsc,
				name_map = OldNameMap,
				rec_var_map = OldRecVarMap, 
				rev_name_map = OldRevNameMap,
				self_rec = OldSelfRec} = CG) ->
  %% Build name map and recursion variable maps.
  {NewNameMap, NewRevNameMap, NewRecVarMap} = 
    build_maps(Tree, OldRecVarMap, OldNameMap, OldRevNameMap),
  
  %% First find the module-local dependencies.
  {Deps0, EscapingFuns, Calls} = dialyzer_dep:analyze(Tree),
  NewCalls = dict:merge(fun(_Key, Val, Val) -> Val end, OldCalls, Calls),
  NewEsc = sets:union(sets:from_list(EscapingFuns), OldEsc),
  LabelEdges = get_edges_from_deps(Deps0),
  
  %% Find the self recursive functions. Named functions get both the
  %% key and their name for convenience.
  SelfRecs0 = lists:foldl(fun({Key, Key}, Acc) -> 
			      case dict:find(Key, NewNameMap) of
				error      -> [Key|Acc];
				{ok, Name} -> [Key, Name|Acc]
			      end;
			     (_, Acc) -> Acc
			  end, [], LabelEdges),
  SelfRecs = sets:union(sets:from_list(SelfRecs0), OldSelfRec),
  
  NamedEdges1 = name_edges(LabelEdges, NewNameMap),
  
  %% We need to scan for inter-module calls since these are not tracked
  %% by dialyzer_dep. Note that the caller is always recorded as the
  %% top level function. This is OK since the included functions are
  %% stored as scc with the parent.
  NamedEdges2 = scan_core_funs(Tree),

  %% Confirm all nodes in the tree.
  Names1 = lists:append([[X, Y] || {X, Y} <- NamedEdges1]),
  Names2 = ordsets:from_list(Names1),

  %% Get rid of the 'top' function from nodes and edges.
  Names3 = ordsets:del_element(top, Names2),
  NewNamedEdges2 =
    [E || {From, To} = E <- NamedEdges2, From =/= top, To =/= top],
  NewNamedEdges1 =
    [E || {From, To} = E <- NamedEdges1, From =/= top, To =/= top],
  NamedEdges3 = NewNamedEdges1 ++ NewNamedEdges2,
  CG1 = add_edges(NamedEdges3, Names3, CG),
  CG1#callgraph{calls = NewCalls,
                esc = NewEsc,
                name_map = NewNameMap,
                rec_var_map = NewRecVarMap, 
                rev_name_map = NewRevNameMap,
                self_rec = SelfRecs}.

build_maps(Tree, RecVarMap, NameMap, RevNameMap) ->
  %% We only care about the named (top level) functions. The anonymous
  %% functions will be analysed together with their parents. 
  Defs = cerl:module_defs(Tree),
  Mod = cerl:atom_val(cerl:module_name(Tree)),
  lists:foldl(fun({Var, Function}, {AccNameMap, AccRevNameMap, AccRecVarMap}) ->
		  FunName = cerl:fname_id(Var),
		  Arity = cerl:fname_arity(Var),
		  MFA = {Mod, FunName, Arity},
		  {dict:store(get_label(Function), MFA, AccNameMap),
		   dict:store(MFA, get_label(Function), AccRevNameMap),
		   dict:store(get_label(Var), MFA, AccRecVarMap)}
	      end, {NameMap, RevNameMap, RecVarMap}, Defs).

get_edges_from_deps(Deps) ->
  %% Convert the dependencies as produced by dialyzer_dep to a list of
  %% edges. Also, remove 'external' since we are not interested in
  %% this information.
  Edges = dict:fold(fun(external, _Set, Acc) -> Acc;
		       (Caller, Set, Acc)    ->
			[[{Caller, Callee} || Callee <- Set, 
					      Callee =/= external]|Acc]
		    end, [], Deps),
  lists:flatten(Edges).

name_edges(Edges, NameMap) ->
  %% If a label is present in the name map it is renamed. Otherwise
  %% keep the label as the identity.
  MapFun = fun(X) ->
	       case dict:find(X, NameMap) of
		 error -> X;
		 {ok, MFA} -> MFA
	       end
	   end,
  name_edges(Edges, MapFun, NameMap, []).

name_edges([{From, To}|Left], MapFun, NameMap, Acc) ->
  NewFrom = MapFun(From),
  NewTo = MapFun(To),
  name_edges(Left, MapFun, NameMap, [{NewFrom, NewTo}|Acc]);
name_edges([], _MapFun, _NameMap, Acc) ->
  Acc.

scan_core_funs(Tree) ->
  Defs = cerl:module_defs(Tree),
  Mod = cerl:atom_val(cerl:module_name(Tree)),
  DeepEdges = lists:foldl(fun({Var, Function}, Edges) ->
			      FunName = cerl:fname_id(Var),
			      Arity = cerl:fname_arity(Var),
			      MFA = {Mod, FunName, Arity},
			      [scan_one_core_fun(Function, MFA)|Edges]
			  end, [], Defs),
  lists:flatten(DeepEdges).

scan_one_core_fun(TopTree, FunName) ->
  FoldFun = fun(Tree, Acc) ->
		case cerl:type(Tree) of
		  call ->
		    CalleeM = cerl:call_module(Tree),
		    CalleeF = cerl:call_name(Tree),
		    A = length(cerl:call_args(Tree)),
		    case (cerl:is_c_atom(CalleeM) andalso 
			  cerl:is_c_atom(CalleeF)) of
		      true -> 
			M = cerl:atom_val(CalleeM),
			F = cerl:atom_val(CalleeF),
			case erl_bif_types:is_known(M, F, A) of
			  true -> Acc;
			  false -> [{FunName, {M, F, A}}|Acc]
			end;
		      false -> 
			%% We cannot handle run-time bindings
			Acc
		    end;
		  _ ->
		    %% Nothing that can introduce new edges in the callgraph.
		    Acc
		end
	    end,
  cerl_trees:fold(FoldFun, [], TopTree).

get_label(T) ->
  case cerl:get_ann(T) of
    [{label, L} | _] when is_integer(L) -> L;
    _ -> erlang:error({missing_label, T})
  end.

%%----------------------------------------------------------------------
%% Digraph
%%----------------------------------------------------------------------

digraph_add_edges([{From, To}|Left], DG) ->
  digraph_add_edges(Left, digraph_add_edge(From, To, DG));
digraph_add_edges([], DG) ->
  DG.

digraph_add_edge(From, To, DG) ->
  case digraph:vertex(DG, From) of
    false -> digraph:add_vertex(DG, From);
    {From, _} -> ok
  end,
  case digraph:vertex(DG, To) of
    false -> digraph:add_vertex(DG, To);
    {To, _} -> ok
  end,
  digraph:add_edge(DG, {From, To}, From, To, []),
  DG.

digraph_confirm_vertices([MFA|Left], DG) ->
  digraph:add_vertex(DG, MFA, confirmed),
  digraph_confirm_vertices(Left, DG);
digraph_confirm_vertices([], DG) ->
  DG.
  
digraph_remove_external(DG) ->
  Vertices = digraph:vertices(DG),
  Unconfirmed = remove_unconfirmed(Vertices, DG),
  {DG, Unconfirmed}.

remove_unconfirmed(Vertexes, DG) ->
  remove_unconfirmed(Vertexes, DG, []).

remove_unconfirmed([V|Left], DG, Unconfirmed) ->
  case digraph:vertex(DG, V) of
    {V, confirmed} -> remove_unconfirmed(Left, DG, Unconfirmed);
    {V, []} -> remove_unconfirmed(Left, DG, [V|Unconfirmed])
  end;
remove_unconfirmed([], DG, Unconfirmed) ->
  BadCalls = lists:append([digraph:in_edges(DG, V) || V <- Unconfirmed]),
  BadCallsSorted = lists:keysort(1, BadCalls),
  digraph:del_vertices(DG, Unconfirmed),
  BadCallsSorted.

digraph_delete(DG) ->
  digraph:delete(DG).

digraph_edges(DG) ->
  digraph:edges(DG).

digraph_vertices(DG) ->
  digraph:vertices(DG).

digraph_in_neighbours(V, DG) ->
  case digraph:in_neighbours(DG, V) of
    [] -> none;
    List -> List
  end.

%% Pick all the independent nodes (leaves) from one module. Then try
%% to stay within the module until no more independent nodes can be
%% chosen. Then pick a new module and so on.
%%
%% Note that an SCC that ranges over more than one module is
%% considered to belong to all modules to make sure that we do not
%% lose any nodes.

digraph_postorder(Digraph) ->
  %% Remove all self-edges for SCCs.
  Edges = [digraph:edge(Digraph, E) || E <- digraph:edges(Digraph)],
  SelfEdges = [E || {E, V, V, _} <- Edges],
  true = digraph:del_edges(Digraph, SelfEdges),
  %% Determine the first module outside of the loop.
  Leaves = digraph_leaves(Digraph),
  case Leaves =:= [] of
    true -> [];
    false ->
      {Module, Taken} = take_sccs_from_fresh_module(Leaves),
      true = digraph:del_vertices(Digraph, Taken),
      digraph_postorder(Digraph, Module, [Taken])
  end.

digraph_postorder(Digraph, LastModule, Acc) ->
  Leaves = digraph_leaves(Digraph),
  case Leaves =:= [] of
    true -> lists:append(lists:reverse(Acc));
    false ->
      case [SCC || SCC <- Leaves, scc_belongs_to_module(SCC, LastModule)] of
	[] ->
	  {NewModule, NewTaken} = take_sccs_from_fresh_module(Leaves),
	  true = digraph:del_vertices(Digraph, NewTaken),
	  digraph_postorder(Digraph, NewModule, [NewTaken|Acc]);
	NewTaken ->
	  true = digraph:del_vertices(Digraph, NewTaken),
	  digraph_postorder(Digraph, LastModule, [NewTaken|Acc])
      end
  end.

digraph_leaves(Digraph) ->
  [V || V <- digraph:vertices(Digraph), digraph:out_degree(Digraph, V) =:= 0].

take_sccs_from_fresh_module(Leaves) ->
  NewModule = find_module(hd(Leaves)),
  {NewModule, 
   [SCC || SCC <- Leaves, scc_belongs_to_module(SCC, NewModule)]}.

-spec scc_belongs_to_module(scc(), module()) -> boolean().

scc_belongs_to_module([Label|Left], Module) when is_integer(Label) ->
  scc_belongs_to_module(Left, Module);
scc_belongs_to_module([{M, _, _}|Left], Module) ->
  if M =:= Module -> true;
     true -> scc_belongs_to_module(Left, Module)
  end;
scc_belongs_to_module([], _Module) ->
  false.
      
-spec find_module(scc()) -> module().

find_module([{M, _, _}|_]) -> M;
find_module([Label|Left]) when is_integer(Label) -> find_module(Left).

digraph_finalize(DG) ->
  DG1 = digraph_utils:condensation(DG),
  Postorder = digraph_postorder(DG1),
  digraph:delete(DG1),
  Postorder.

digraph_reaching_subgraph(Funs, DG) ->  
  Vertices = digraph_utils:reaching(Funs, DG),
  digraph_utils:subgraph(DG, Vertices).

%%----------------------------------------------------------------------
%% Races
%%----------------------------------------------------------------------

-spec cleanup(callgraph()) -> callgraph().

cleanup(#callgraph{name_map = NameMap,
                   rev_name_map = RevNameMap,
                   public_tables = PublicTables,
                   named_tables = NamedTables,
                   race_code = RaceCode}) ->
  #callgraph{name_map = NameMap,
             rev_name_map = RevNameMap,
             public_tables = PublicTables,
             named_tables = NamedTables,
             race_code = RaceCode}.

-spec get_digraph(callgraph()) -> digraph().

get_digraph(#callgraph{digraph = Digraph}) ->
  Digraph.

-spec get_named_tables(callgraph()) -> [string()].

get_named_tables(#callgraph{named_tables = NamedTables}) ->
  NamedTables.

-spec get_public_tables(callgraph()) -> [label()].

get_public_tables(#callgraph{public_tables = PT}) ->
  PT.

-spec get_race_code(callgraph()) -> dict().

get_race_code(#callgraph{race_code = RaceCode}) ->
  RaceCode.

-spec get_race_detection(callgraph()) -> boolean().

get_race_detection(#callgraph{race_detection = RD}) ->
  RD.

-spec race_code_new(callgraph()) -> callgraph().

race_code_new(Callgraph) ->
  Callgraph#callgraph{race_code = dict:new()}.

-spec put_race_code(dict(), callgraph()) -> callgraph().

put_race_code(RaceCode, Callgraph) ->
  Callgraph#callgraph{race_code = RaceCode}.

-spec put_race_detection(boolean(), callgraph()) -> callgraph().

put_race_detection(RaceDetection, Callgraph) ->
  Callgraph#callgraph{race_detection = RaceDetection}.

-spec put_named_tables([string()], callgraph()) -> callgraph().

put_named_tables(NamedTables, Callgraph) ->
  Callgraph#callgraph{named_tables = NamedTables}.

-spec put_public_tables([label()], callgraph()) -> callgraph().

put_public_tables(PublicTables, Callgraph) ->
  Callgraph#callgraph{public_tables = PublicTables}.

%%=============================================================================
%% Utilities for 'dot'
%%=============================================================================

-spec to_dot(callgraph(), file:filename()) -> 'ok'.

to_dot(#callgraph{digraph = DG, esc = Esc} = CG, File) ->
  Fun = fun(L) ->
	    case lookup_name(L, CG) of
	      error -> L;
	      {ok, Name} -> Name
	    end
	end,
  Escaping = [{Fun(L), {color, red}} 
	      || L <- sets:to_list(Esc), L =/= external],
  Vertices = digraph_edges(DG),
  hipe_dot:translate_list(Vertices, File, "CG", Escaping).

-spec to_ps(callgraph(), file:filename(), string()) -> 'ok'.

to_ps(#callgraph{} = CG, File, Args) ->
  Dot_File = filename:rootname(File) ++ ".dot",
  to_dot(CG, Dot_File),
  Command = io_lib:format("dot -Tps ~s -o ~s ~s", [Args, File, Dot_File]),
  _ = os:cmd(Command),
  ok.

%-------------------------------------------------------------------------------

-spec put_behaviour_api_calls([{mfa(), mfa()}], callgraph()) -> callgraph().

put_behaviour_api_calls(Calls, Callgraph) ->
  Callgraph#callgraph{beh_api_calls = Calls}.

-spec get_behaviour_api_calls(callgraph()) -> [{mfa(), mfa()}].

get_behaviour_api_calls(Callgraph) ->
  Callgraph#callgraph.beh_api_calls.