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%-----------------------------------------------------------------------------%
% Copyright (C) 1996-1999 The University of Melbourne.
% This file may only be copied under the terms of the GNU General
% Public License - see the file COPYING in the Mercury distribution.
%-----------------------------------------------------------------------------%
%
% Utility predicates used in two or more of the modules concerned with
% determinism: switch_detection, cse_detection, det_analysis, det_report
% and simplify.
%
% Main authors: fjh and zs.
%
%-----------------------------------------------------------------------------%
:- module det_util.
:- interface.
:- import_module hlds_module, hlds_pred, hlds_goal, hlds_data, globals.
:- import_module instmap, prog_data.
:- import_module bool, set, list.
:- type maybe_changed ---> changed ; unchanged.
:- type det_info.
% Given a goal and an initial instmap, compute the final instmap that
% results from the initial instmap after execution of the goal.
:- pred update_instmap(hlds_goal, instmap, instmap).
:- mode update_instmap(in, in, out) is det.
% Given a list of cases, and a list of the possible cons_ids
% that the switch variable could be bound to, select out only
% those cases whose cons_id occurs in the list of cases
% We assume that the list of cases and the list of cons_ids
% are sorted, so that we can do this using a simple sorted merge.
:- pred delete_unreachable_cases(list(case), list(cons_id),
list(case)).
:- mode delete_unreachable_cases(in, in, out) is det.
% Update the current substitution to account for the effects
% of the given unification.
:- pred interpret_unify(prog_var, unify_rhs, prog_substitution,
prog_substitution).
:- mode interpret_unify(in, in, in, out) is semidet.
% Look up the determinism of a procedure.
:- pred det_lookup_detism(det_info, pred_id, proc_id, determinism).
:- mode det_lookup_detism(in, in, in, out) is det.
:- pred det_get_proc_info(det_info, proc_info).
:- mode det_get_proc_info(in, out) is det.
:- pred det_lookup_var_type(module_info, proc_info, prog_var, hlds_type_defn).
:- mode det_lookup_var_type(in, in, in, out) is semidet.
:- pred det_no_output_vars(set(prog_var), instmap, instmap_delta, det_info).
:- mode det_no_output_vars(in, in, in, in) is semidet.
:- pred det_info_init(module_info, pred_id, proc_id, globals, det_info).
:- mode det_info_init(in, in, in, in, out) is det.
:- pred det_info_get_module_info(det_info, module_info).
:- mode det_info_get_module_info(in, out) is det.
:- pred det_info_get_pred_id(det_info, pred_id).
:- mode det_info_get_pred_id(in, out) is det.
:- pred det_info_get_proc_id(det_info, proc_id).
:- mode det_info_get_proc_id(in, out) is det.
:- pred det_info_get_reorder_conj(det_info, bool).
:- mode det_info_get_reorder_conj(in, out) is det.
:- pred det_info_get_reorder_disj(det_info, bool).
:- mode det_info_get_reorder_disj(in, out) is det.
:- pred det_info_get_fully_strict(det_info, bool).
:- mode det_info_get_fully_strict(in, out) is det.
:- pred det_info_set_module_info(det_info, module_info, det_info).
:- mode det_info_set_module_info(in, in, out) is det.
%-----------------------------------------------------------------------------%
:- implementation.
:- import_module inst_match, mode_util, type_util, options, term.
:- import_module map, require, std_util.
update_instmap(_Goal0 - GoalInfo0, InstMap0, InstMap) :-
goal_info_get_instmap_delta(GoalInfo0, DeltaInstMap),
instmap__apply_instmap_delta(InstMap0, DeltaInstMap, InstMap).
delete_unreachable_cases([], _, []).
delete_unreachable_cases([_ | _], [], []).
delete_unreachable_cases([Case | Cases0], [ConsId | ConsIds], Cases) :-
Case = case(CaseConsId, _DisjList),
( CaseConsId = ConsId ->
Cases = [Case | Cases1],
delete_unreachable_cases(Cases0, ConsIds, Cases1)
; compare(<, CaseConsId, ConsId) ->
delete_unreachable_cases(Cases0, [ConsId | ConsIds], Cases)
;
delete_unreachable_cases([Case | Cases0], ConsIds, Cases)
).
interpret_unify(X, var(Y), Subst0, Subst) :-
term__unify(term__variable(X), term__variable(Y),
Subst0, Subst).
interpret_unify(X, functor(ConsId, ArgVars), Subst0, Subst) :-
term__var_list_to_term_list(ArgVars, ArgTerms),
cons_id_and_args_to_term(ConsId, ArgTerms, RhsTerm),
term__unify(term__variable(X), RhsTerm, Subst0, Subst).
interpret_unify(_X, lambda_goal(_POrF, _Method, _Fix, _NonLocals,
_Vars, _Modes, _Det, _Goal), Subst0, Subst) :-
% For ease of implementation we just ignore unifications with
% lambda terms. This is a safe approximation, it just
% prevents us from optimizing them as well as we would like.
Subst = Subst0.
det_lookup_detism(DetInfo, PredId, ModeId, Detism) :-
det_info_get_module_info(DetInfo, ModuleInfo),
module_info_preds(ModuleInfo, PredTable),
map__lookup(PredTable, PredId, PredInfo),
pred_info_procedures(PredInfo, ProcTable),
map__lookup(ProcTable, ModeId, ProcInfo),
proc_info_interface_determinism(ProcInfo, Detism).
det_get_proc_info(DetInfo, ProcInfo) :-
det_info_get_module_info(DetInfo, ModuleInfo),
det_info_get_pred_id(DetInfo, PredId),
det_info_get_proc_id(DetInfo, ProcId),
module_info_preds(ModuleInfo, PredTable),
map__lookup(PredTable, PredId, PredInfo),
pred_info_procedures(PredInfo, ProcTable),
map__lookup(ProcTable, ProcId, ProcInfo).
det_lookup_var_type(ModuleInfo, ProcInfo, Var, TypeDefn) :-
proc_info_vartypes(ProcInfo, VarTypes),
map__lookup(VarTypes, Var, Type),
( type_to_type_id(Type, TypeId, _) ->
module_info_types(ModuleInfo, TypeTable),
map__search(TypeTable, TypeId, TypeDefn)
;
error("cannot lookup the type of a variable")
).
det_no_output_vars(Vars, InstMap, InstMapDelta, DetInfo) :-
det_info_get_module_info(DetInfo, ModuleInfo),
instmap__no_output_vars(InstMap, InstMapDelta, Vars, ModuleInfo).
%-----------------------------------------------------------------------------%
:- type det_info ---> det_info(
module_info,
pred_id, % the id of the proc
proc_id, % currently processed
bool, % --reorder-conj
bool, % --reorder-disj
bool % --fully-strict
).
det_info_init(ModuleInfo, PredId, ProcId, Globals, DetInfo) :-
globals__lookup_bool_option(Globals, reorder_conj, ReorderConj),
globals__lookup_bool_option(Globals, reorder_disj, ReorderDisj),
globals__lookup_bool_option(Globals, fully_strict, FullyStrict),
DetInfo = det_info(ModuleInfo, PredId, ProcId,
ReorderConj, ReorderDisj, FullyStrict).
det_info_get_module_info(det_info(ModuleInfo, _, _, _, _, _), ModuleInfo).
det_info_get_pred_id(det_info(_, PredId, _, _, _, _), PredId).
det_info_get_proc_id(det_info(_, _, ProcId, _, _, _), ProcId).
det_info_get_reorder_conj(det_info(_, _, _, ReorderConj, _, _), ReorderConj).
det_info_get_reorder_disj(det_info(_, _, _, _, ReorderDisj, _), ReorderDisj).
det_info_get_fully_strict(det_info(_, _, _, _, _, FullyStrict), FullyStrict).
det_info_set_module_info(det_info(_, B, C, D, E, F), ModuleInfo,
det_info(ModuleInfo, B, C, D, E, F)).
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