1		% (c) 2009-2024 Lehrstuhl fuer Softwaretechnik und Programmiersprachen,
2		% Heinrich Heine Universitaet Duesseldorf
3		% This software is licenced under EPL 1.0 (http://www.eclipse.org/org/documents/epl-v10.html)
4
5		:- module(model_checker,[is_deadlocked/1, node_satisfies_goal/1,
6		open_search/12,
7		expired_static_analysis_time/1,
8		proof_info_model_checking_incomplete/5, model_checking_is_incomplete/6,
9		perform_static_analyses/3, compute_transitions_opt/3,
10		get_model_check_stats/6,
11		find_invariant_error/4]).
12
13		:- use_module(module_information).
14		:- module_info(group,model_checker).
15		:- module_info(description,'The core model checker (does not treat LTL).').
16
17		:- use_module(b_interpreter,[state_violates_assertions/2]).
18		:- use_module(error_manager,[enter_new_error_scope/1, exit_error_scope/3, error_occurred_in_error_scope/0,
19		add_internal_error/2]).
20
21		:- use_module(specfile,[animation_mode/1,csp_mode/1]).
22		:- use_module(state_space,[visited_expression/2,transition/3, operation_not_yet_covered/1]).
23
24		:- use_module(probporsrc(static_analysis),[compute_dependendency_relation_of_all_events_in_the_model/3]).
25		:- use_module(probpgesrc(pge_algo), [compute_transitions_pge/2,compute_operation_relations_for_pge_if_necessary/2]).
26
27		:- use_module(state_space_exploration_modes,[depth_breadth_first_mode/1]).
28		:- use_module(bmachine,[b_machine_has_constants/0]).
29		:- use_module(state_space,[multiple_concrete_constants_exist/0]).
30
31		:- dynamic mc_found_error/2.
32
33		/* open_search: search for errors/goals among open nodes (i.e., not yet processed nodes)*/
34		/* LimitNr: max number of nodes to check, NodesAnalysed: number of nodes checked */
35		open_search(LimitNr,NodesAnalysed,LimitTime,Res,FindDeadlocks,FindInvViolations,
36		FindGoal,FindAssViolations,FindStateErrors,
37		StopAtFullCoverage,PartialOrderReduction,PartialGuardEvaluation) :-
38		animation_mode(MODE),
39		retractall(mc_found_error(_,_)),
40		initialise_optimisations(MODE,PartialOrderReduction,PartialGuardEvaluation,FindInvViolations,Optimisations),
41		perform_static_analyses(MODE,FindInvViolations,Optimisations),
42		%(error_manager:real_error_occurred -> print(error_after_perform_static_analyses),nl ; true),
43		depth_breadth_first_mode(DFMODE),
44		preferences:temporary_set_preference(do_invariant_checking,true,CHNG),
45		statistics(walltime,[ReferenceTime,_]),
46		get_model_check_stats(States,_Transitions,ProcessedTotal,Percentage,_,_),
47		% MEMO: used to cache expanded concrete_constants values
48		% particularly useful, e.g., for ../prob_examples/public_examples/B/PerformanceTests/LiftLargeWithLargeCst.mch
49		((\+ b_machine_has_constants ; multiple_concrete_constants_exist)
50		-> MEMO = '$disabled' % it could still be useful to cache one constant setup ??
51		; true),
52		enter_new_error_scope(ScopeID),
53		set_context_state(root),
54		open_search10(0,LimitNr,refstatus(ReferenceTime,Percentage,States,ProcessedTotal,ReferenceTime),
55		NodesAnalysed,LimitTime,MCRes,FindDeadlocks,FindInvViolations,
56		FindGoal,FindAssViolations,FindStateErrors,
57		StopAtFullCoverage,Optimisations,MODE,DFMODE,MEMO),
58		%tools_printing:print_term_summary(memo(MEMO)),nl,
59		exit_error_scope(ScopeID,_,open_search),
60		preferences:reset_temporary_preference(do_invariant_checking,CHNG),
61		clear_context_state,
62		(no_error_found_result(MCRes),
63		mc_found_error(Res,ID) % stored error because of mc_continue_after_error
64		-> set_counter_example_last_node(ID)
65		; Res=MCRes).
66
67		no_error_found_result(no).
68		no_error_found_result(all).
69
70		:- use_module(probsrc(tools),[statistics_memory_used/1]).
71		:- use_module(probsrc(debug),[silent_mode/1, formatsilent/3]).
72		:- use_module(library(random)).
73		open_search10(Nr,LimitNr,RefStatus,NodesAnalysed,LimitTime,Res,
74		FindDeadlocks,FindInvViolations,FindGoal,FindAssViolations,FindStateErrors,
75		SFC,Optimisations,MODE,DF,MEMO) :-
76		%print(open_search(Nr,LimitNr,RefStatus)),nl,
77		Nr < LimitNr,!,
78		(\+ number(LimitTime)
79		-> open_search_do_one_node(Nr,LimitNr,RefStatus,NodesAnalysed,LimitTime,Res,
80		FindDeadlocks,FindInvViolations,FindGoal,FindAssViolations,FindStateErrors,
81		SFC,Optimisations,MODE,DF,MEMO)
82		; statistics(walltime,[NewTime,_]),
83		(Nr mod 25 =:= 24, silent_mode(off) %, Nr\=0
84		-> RefStatus = refstatus(RefTime,RefPerc,PrevStates,PrevProcessed,StartTime),
85		Delta is NewTime-RefTime,
86		(Delta>20000 % more than 20 seconds since last progress message
87		% ; random(0,20000,X), X=<Delta)
88		-> get_model_check_stats(States,Transitions,ProcessedTotal,Perc,Ignored,ScopePerc),
89		(Ignored>0
90		-> format('~n* ~w states checked (~1f% of total ~w, ~1f% wo ~w ignored), ~w transitions,',
91		[ProcessedTotal,Perc,States,ScopePerc,Ignored,Transitions])
92		; get_current_breadth_first_level(Level)
93		-> format('~n* ~w states checked (~1f% of total ~w), ~w transitions, bf-level ~w, ',
94		[ProcessedTotal,Perc,States,Transitions,Level])
95		; format('~n* ~w states checked (~1f% of total ~w), ~w transitions,',
96		[ProcessedTotal,Perc,States,Transitions])
97		),
98		findall(Op,operation_not_yet_covered(Op),NotCov), length(NotCov,NrNotCov),
99		(NrNotCov = 1 -> format(' 1 operation not covered,',[])
100		; NrNotCov > 0 -> format(' ~w operations not covered,',[NrNotCov]) ; true),
101		statistics_memory_used(M), tools:print_mb(M),
102		DeltaProcessedStates is (ProcessedTotal-PrevProcessed),
103		NodesProcessedPerSec is DeltaProcessedStates*1000 / (NewTime-RefTime),
104		format('~n* currently checking ~2f states/sec',[NodesProcessedPerSec]),
105		DeltaStates is (States-PrevStates),
106		NodesPerSec is DeltaStates*1000 / (NewTime-RefTime),
107		format(', adding ~2f new states/sec~n',[NodesPerSec]),
108		RefStatus1 = refstatus(NewTime,Perc,States,ProcessedTotal,StartTime),
109		FullDeltaTime is NewTime - StartTime,
110		FullDeltaTimeMinutes is FullDeltaTime / 60000.0,
111		(Perc>RefPerc -> format('* walltime ~1f minutes~n',[FullDeltaTimeMinutes])
112		; format('* walltime ~1f minutes, percentage of checked states decreasing from ~1f%~n',[FullDeltaTimeMinutes,RefPerc]))
113		; RefStatus1 = RefStatus
114		)
115		; RefStatus1 = RefStatus
116		),
117		(NewTime>LimitTime, Nr>0
118		-> Res = [timeout,Nr], NodesAnalysed=Nr
119		; open_search_do_one_node(Nr,LimitNr,RefStatus1,NodesAnalysed,LimitTime,Res,
120		FindDeadlocks,FindInvViolations,FindGoal,FindAssViolations,FindStateErrors,
121		SFC,Optimisations,MODE,DF,MEMO))
122		).
123		open_search10(N,_LimitNr,_RefStatus,N,_,no ,_,_,_,_,_,_,_,_,_,_MEMO).
124
125		% States: total number of states encounetered
126		% ProcessedTotal: number of states already processed
127		% Percentage: percentate of total processed
128		% Ignored: number of states ignored because not satisfying SCOPE predicate
129		% ScopePercentage: percentage processed taking into account ignored states
130		get_model_check_stats(States,Transitions,ProcessedTotal,Percentage,Ignored,ScopePercentage) :-
131		get_state_space_stats(States,Transitions,ProcessedTotal,Ignored),
132		Percentage is (100*ProcessedTotal / States),
133		InScope is (States-Ignored),
134		(InScope > 0 -> ScopePercentage is (100*ProcessedTotal / InScope) ; ScopePercentage = 100).
135
136		:- use_module(preferences,[preference/2]).
137		:- use_module(specfile,[prepare_state_for_specfile_trans/4]).
138		open_search_do_one_node(Nr,LimitNr,RefStatus,NodesAnalysed,LimitTime,Res,
139		FindDeadlocks,FindInvViolations,
140		FindGoal,FindAssViolations,FindStateErrors,
141		StopAtFullCoverage,Optimisations,MODE,DFMODE,MEMO) :-
142	?	get_next_node_to_check(FindInvViolations,ID,MODE,DFMODE),!,
143		update_context_state(ID), %print(treating_node(ID)),nl,
144
145		(preference(ignore_hash_collisions,true),
146		preference(forget_state_space,true)
147		-> retract_visited_expression(ID,CurState) %, retractall(id_to_marker(ID,_)) not necessary
148		; visited_expression(ID,CurState)),
149		(FindInvViolations=1 % compute invariant status
150		-> prepare_state_for_specfile_trans(CurState,ID,MEMO,PCurState),
151		tcltk_interface:compute_invariant_if_necessary(ID,PCurState,MODE)
152		; CurState=PCurState),
153		%print(processed_invariant(ID)), statistics(memory_used,M), tools:print_mb(M),nl,
154		!,
155		compute_transitions_opt(Optimisations,ID,PCurState),
156		%tools:print_message(mc(ID)),
157		%print(computed_all_transitions(ID)), statistics(memory_used,M2), tools:print_mb(M2),nl,
158		% !,
159	?	(open_search_check_for_error(ID,PCurState,Res,
160		FindDeadlocks,FindInvViolations,FindGoal,FindAssViolations,
161		FindStateErrors,StopAtFullCoverage,MODE)
162		-> print_found_error(Res,ID),
163		NodesAnalysed=Nr,
164		set_counter_example_last_node(ID)
165		; N1 is Nr + 1,
166		open_search10(N1,LimitNr,RefStatus,NodesAnalysed,LimitTime,Res,
167		FindDeadlocks,FindInvViolations,FindGoal,FindAssViolations,FindStateErrors,StopAtFullCoverage,
168		Optimisations,MODE,DFMODE,MEMO)
169		).
170		open_search_do_one_node(N,_LimitNr,_RefStatus,N,_,all,_,_,_,_,_,_,_,_,_,_MEMO) :-
171		formatsilent(user_output,'% Model checking finished, all open states visited~n',[]).
172
173		set_counter_example_last_node(ID) :-
174		tcltk_interface:tcltk_execute_trace_to_node(ID). % TO DO: allow to disable this when -nocounter option given
175
176		:- use_module(tools_printing,[format_with_colour_nl/4]).
177		print_found_error(goal_found,ID) :- !,
178		format_with_colour_nl(user_output,[green],'Found GOAL in state id ~w',[ID]).
179		print_found_error(full_coverage,ID) :- !,
180		format_with_colour_nl(user_output,[green],'Full coverage achieved in state id ~w',[ID]).
181		print_found_error(state_error(X),ID) :- nonvar(X),functor(X,F,_),!, % only print functor; term can be big
182		format_with_colour_nl(user_error,[red],'Found "~w" in state id ~w',[F,ID]).
183		print_found_error(X,ID) :-
184		format_with_colour_nl(user_error,[red],'Found "~w" error in state id ~w',[X,ID]).
185
186
187		%% Optimisation options (see first argument 'Optimisations'):
188		compute_transitions_opt(Optimisations,ID,CurState) :-
189		Optimisations = opt(PORPrefs,PGEPref),
190		compute_transitions(PORPrefs,PGEPref,ID,CurState).
191
192		compute_transitions(PORPrefs,_PGEPref,ID,CurState) :-
193		PORPrefs = por(POROption,_UseEnableGraph,_Depth,_UsePGE),
194		(POROption==ample_sets;POROption==ample_sets2),!,
195		tcltk_interface: compute_ample_set(ID,CurState,PORPrefs).
196		compute_transitions(_,PGEPref,ID,CurState) :-
197		PGEPref \= off,!,
198		compute_transitions_pge(ID,CurState). % from pge_algo
199		compute_transitions(_,_,ID,CurState) :-
200		tcltk_interface: compute_all_transitions(ID,CurState).
201
202		:- use_module(preferences,[get_preference/2]).
203		:- use_module(specfile,[b_or_z_mode/1]).
204		:- use_module(state_space_exploration_modes,[get_open_node_to_check/2, get_current_breadth_first_level/1]).
205		%%get_next_node_to_check(1,ID,_) :- state_space:not_invariant_checked(ID). % if there is an existing node whose invariant we have not yet checked: check it now
206		get_next_node_to_check(_,ID,AnimMODE,DFMODE) :-
207		%(nonvar(ID) -> print(nonvar(ID)),nl ; true),
208	?	get_open_node_to_check(DFMODE,ID),
209		(b_or_z_mode(AnimMODE) -> assertz(not_invariant_checked(ID)) ; true).
210
211
212		:- use_module(state_space).
213		open_search_check_for_error(ID,PCurState,Res,
214		FindDeadlocks,FindInvViolations,FindGoal,FindAssViolations,
215		FindStateErrors,StopAtFullCoverage,MODE) :-
216	?	open_search_found_error(ID,PCurState,Res,
217		FindDeadlocks,FindInvViolations,FindGoal,FindAssViolations,
218		FindStateErrors,StopAtFullCoverage,MODE),
219		(get_preference(mc_continue_after_error,false)
220		-> true
221		; print_found_error(Res,ID), % just print the error and try find more
222		%ajoin(['Found at state ',ID,':'],Msg), add_error(model_checker,'Found error:'Res),
223		% we could call analyse_invariant_for_state(ID)
224		\+ mc_found_error(_,_),
225		assertz(mc_found_error(Res,ID)), % store error to replay at end
226		fail
227		).
228
229		open_search_found_error(ID,CurState,Error,
230		_FindDeadlocks,1,_FindGoal,_FindAssViolations,_FindStateErrors,_StopAtFullCoverage,MODE) :-
231	?	find_invariant_error(MODE,ID,CurState,Error).
232		open_search_found_error(ID,_CurState,deadlock,1,_,_,_,_,_,_) :-
233		is_deadlocked(ID). %, print(deadlock(ID)),nl.
234		open_search_found_error(ID,CurState,assertion_violation,_,_,_,1,_,_,_MODE) :-
235		state_violates_assertions(ID,CurState).
236		open_search_found_error(ID,_CurState,ERR,_,_,_,_,1,_,_MODE) :-
237	?	state_space:state_error(ID,_,Error),
238		Error \== invariant_violated,
239		ERR = state_error(Error).
240		open_search_found_error(_ID,_CurState,general_error_occurred,_,_,_,_,1,_,_MODE) :-
241		error_occurred_in_error_scope. % enter_new_error_scope set up in open_search
242		%% we no longer use: error_manager:real_error_occurred ; errors can happen e.g. in POR static analysis
243		open_search_found_error(ID,_CurState,goal_found,_,_,1,_,_,_,MODE) :-
244		node_satisfies_goal(ID,MODE).
245		open_search_found_error(_ID,_CurState,full_coverage,_,_,_,_,_,1,_MODE) :- % StopAtFullCoverage = 1
246		\+ operation_not_yet_covered(_).
247
248		find_invariant_error(b,ID,_CurState,invariant_violation) :- !, % here we know that invariant information has been computed
249		(invariant_violated(ID) -> true).
250		%find_invariant_error(b,_ID,CurState,invariant_false) :- !,
251		% preference(double_evaluation_when_analysing,true), % DOUBLE_EVALUATION
252		% CurState \= root, CurState \= concrete_constants(_),
253		% specfile:expand_const_and_vars_to_full_store(CurState,FullState), %print(eval_neg_inv(_ID)),nl,
254		% (b_interpreter:state_satisfies_negation_of_invariant(FullState)->true).
255		find_invariant_error(cspm,ID,_CurState,csp_error) :- !, % we know that only csp_can be possible
256		is_csp_error_state(ID).
257		find_invariant_error(MODE,ID,CurState,invariant_violation) :-
258		tcltk_interface:check_invariantKO(MODE,ID,CurState).
259		find_invariant_error(csp_and_b,ID,_CurState,csp_error) :- !, % xtl mode cannot apply
260		is_csp_error_state(ID).
261		find_invariant_error(MODE,ID,CurState,xtl_error) :-
262	?	is_xtl_error_state(ID,CurState,MODE).
263
264		:- use_module(error_manager,[add_warning/3]).
265		is_deadlocked(ID) :-
266		preferences:preference(forget_state_space,true),!, /* transitions not added */
267		(retract(state_space:transition(ID,_,_,_)) -> fail ; true).
268		is_deadlocked(ID) :- % ID must be ground upon call
269		%% visited_expression_id(ID),
270		deadlocked_state(ID),
271		\+ max_reached_or_timeout_for_node(ID),
272		(get_preference(store_only_one_incoming_transition,true)
273		-> add_warning(model_checker,'Deadlock may not exist and be caused by preference SAFETY_MODEL_CHECK being TRUE: ',ID)
274		; true).
275		/* \+((transition(ID,_,NID),NID \= ID)). <-- to detect more liberal form of DEADLOCK */
276
277		is_csp_error_state(ID) :-
278		transition(ID,io(_,error,_),_). /* <--- THE CSP has raised the error channel */
279
280		:- use_module(xtl_interface,[xtl_property/2]).
281		is_xtl_error_state(_ID,CurState,xtl) :-
282	?	xtl_property(CurState,unsafe). /* <--- XTL has found unsafe configuration */
283		% ; AM=promela -> promela_property(CurState,unsafe)
284		% ; AM=smv -> smv_property(CurState,unsafe) ).
285
286
287		:- use_module(specfile,[ animation_mode/1, b_or_z_mode/1, csp_mode/1]).
288
289		node_satisfies_goal(NodeID) :-
290		animation_mode(MODE),
291		node_satisfies_goal(NodeID,MODE).
292
293		:- use_module(bmachine,[b_get_machine_goal/1]).
294		node_satisfies_goal(NodeID,MODE) :- b_or_z_mode(MODE), !,
295		b_get_machine_goal(Goal),
296		eclipse_interface:test_boolean_expression_in_node(NodeID,Goal,'model checking GOAL').
297		node_satisfies_goal(NodeID,MODE) :- csp_mode(MODE),
298		transition(NodeID,io(_,goal,_),_).
299		% TO DO: allow XTL goal_found xtl_property ?
300		% TO DO: allow LTL atomic properties like e(Op1), ...
301		% TO DO: seperate machine GOAL from MC goal; provide intermediate PROB fact and set_mc_goal/1
302
303		% ---------------------------------------
304
305		:- use_module(tools, [ajoin/2]).
306		:- use_module(symsrc(symmetry_marker),[hash_model_checking_imprecise/2]).
307		% Note: we do not need mcFindStateErrors flag
308		%model_checking_is_unsound(FindInvViolations,FindDeadlocks,FindGoal,FindAssViolations,Msg,Term)
309		model_checking_is_incomplete(FindInvViolations,FindDeadlocks,FindGoal,FindAssViolations,Msg,'') :-
310		proof_info_model_checking_incomplete(FindInvViolations,FindDeadlocks,FindGoal,FindAssViolations,Msg).
311		model_checking_is_incomplete(_FindInv,_FindDeadlocks,_FindGoal,_FindAss,Msg,Term) :-
312	?	(get_preference(symmetry_mode,hash),hash_model_checking_imprecise(ID,BasicType)
313		-> Msg = '*** Possibly not all states computed, symmetry hashing may be imprecise, e.g., for variable ',
314		translate:pretty_type(BasicType,S),
315		ajoin([ID,' : ',S],Term)).
316		model_checking_is_incomplete(1,_FindDeadlocks,_FindGoal,_FindAss,Msg,Term) :-
317		(time_out_for_invariant(ID)
318		-> Msg = '*** Timeout(s) occured during invariant computation, e.g., state with id = ', Term=ID).
319		model_checking_is_incomplete(_FindInv,_FindDeadlocks,_FindGoal,1,Msg,Term) :-
320		(time_out_for_assertions(ID)
321		-> Msg = '*** Timeout(s) occured during evaluation of ASSERTIONS, e.g., state with id = ', Term=ID).
322		model_checking_is_incomplete(_FindInv,_FindDeadlocks,_FindGoal,_FindAss,Msg,Term) :-
323	?	(max_reached_for_node(ID)
324		-> ((ID=root ; is_concrete_constants_state_id(ID))
325		-> get_preference(maxNrOfInitialisations,MI),
326		ajoin(['*** Not all transitions were computed as MAX_INITIALISATIONS=',MI,' was too small, e.g., for state with id = '],Msg)
327		; get_preference(maxNrOfEnablingsPerOperation,MO),
328		ajoin(['*** Not all transitions were computed as MAX_OPERATIONS=',MO,' was too small, e.g., for state with id = '],Msg)
329		),
330		Term=ID).
331		model_checking_is_incomplete(_FindInv,_FindDeadlocks,_FindGoal,_FindAss,Msg,Term) :-
332	?	(time_out_for_node(ID,Op,Reason) ->
333		functor(Reason,Func,_), % time_out or virtual_time_out
334		ajoin(['*** Not all transitions were computed due to a ', Func,', e.g., for ',Op, ' and state with id = '],Msg),
335		Term=ID).
336		model_checking_is_incomplete(_FindInv,_FindDeadlocks,_FindGoal,_FindAss,Msg,'') :-
337		get_preference(ignore_hash_collisions,true),
338		Msg = '*** Possibly not all states computed due to IGNORE_HASH_COLLISIONS preference'.
339
340		:- use_module(bmachine, [b_machine_has_proven_invariants/0, b_machine_has_unproven_assertions/0]).
341		proof_info_model_checking_incomplete(1,_FindDeadlocks,_FindGoal,0,Msg) :-
342		b_machine_has_proven_invariants,
343		preferences:get_preference(use_po,true),
344		b_machine_has_unproven_assertions,
345		Msg = '*** Using proof information (-p PROOF_INFO TRUE) is potentially incomplete when not checking theorems (-noass) !'.
346
347
348		% disable POR if not applicable + merge POR/PGE info into one atom for easier lookup in compute_transitions
349		initialise_optimisations(MODE,PartialOrderReduction,PartialGuardEvaluation,FindInvViolations,Optimisations) :-
350		MODE == b,
351		!,
352		((PartialOrderReduction == ample_sets; PartialOrderReduction == ample_sets2) ->
353		get_preference(enable_graph,UseEnableGraph),
354		get_preference(enable_graph_depth,Depth),
355		PORPrefs = por(PartialOrderReduction,UseEnableGraph,Depth,PartialGuardEvaluation),
356		Optimisations = opt(PORPrefs,PartialGuardEvaluation),
357		(FindInvViolations == 1 -> assertz(ample_sets:check_cycle_proviso);true)
358		; PartialGuardEvaluation \= off ->
359		Optimisations = opt(off,PartialGuardEvaluation)
360		;
361		Optimisations = opt(off,off)).
362		initialise_optimisations(_,_,_,_,opt(off,off)).
363
364
365		:- dynamic expired_static_analysis_time/1.
366		perform_static_analyses(MODE,FindInvViolations,opt(PORPrefs,PGEPref)) :-
367		MODE == b,
368		!,
369		retractall(expired_static_analysis_time(_)),
370		statistics(runtime,[T1,_]),
371	?	(perform_static_analyses_aux(PORPrefs,PGEPref,FindInvViolations) -> true
372		; add_internal_error('POR static analysis failed:',perform_static_analyses_aux(PORPrefs,PGEPref,FindInvViolations))
373		),
374		statistics(runtime,[T2,_]),
375		D is T2-T1,
376		assertz(expired_static_analysis_time(D)).
377		perform_static_analyses(_,_,_) :- retractall(expired_static_analysis_time(_)).
378
379		perform_static_analyses_aux(off,off,_FindInvViolations) :- !.
380		perform_static_analyses_aux(PORPrefs,PGEPref,FindInvViolations) :-
381		PORPrefs = por(POROption,_UseEnableGraph,_Depth,_),
382		(POROption==ample_sets;POROption==ample_sets2),!,
383		compute_dependendency_relation_of_all_events_in_the_model(FindInvViolations,PORPrefs,_EnableGraph),
384	?	compute_operation_relations_for_pge_if_necessary(PGEPref,FindInvViolations).
385		perform_static_analyses_aux(_,PGEPref,FindInvViolations) :-
386		compute_operation_relations_for_pge_if_necessary(PGEPref,FindInvViolations).
387		perform_static_analyses_aux(_,_,_).