Files
mercury/compiler/clause_to_proc.m
Zoltan Somogyi be5b71861b Convert almost all the compiler modules to use . instead of __ as
Estimated hours taken: 6
Branches: main

compiler/*.m:
	Convert almost all the compiler modules to use . instead of __ as
	the module qualifier.

	In some cases, change the names of predicates and types to make them
	meaningful without the module qualifier. In particular, most of the
	types that used to be referred to with an "mlds__" prefix have been
	changed to have a "mlds_" prefix instead of changing the prefix to
	"mlds.".

	There are no algorithmic changes.
2006-03-17 01:40:46 +00:00

591 lines
22 KiB
Mathematica

%-----------------------------------------------------------------------------%
% vim: ft=mercury ts=4 sw=4 et
%-----------------------------------------------------------------------------%
% Copyright (C) 1995-2006 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.
%-----------------------------------------------------------------------------%
:- module check_hlds.clause_to_proc.
:- interface.
:- import_module hlds.hlds_module.
:- import_module hlds.hlds_pred.
:- import_module list.
:- import_module std_util.
% In the hlds, we initially record the clauses for a predicate
% in the clauses_info data structure which is part of the
% pred_info data structure. But once the clauses have been
% type-checked, we want to have a separate copy of each clause
% for each different mode of the predicate, since we may
% end up reordering the clauses differently in different modes.
% Here we copy the clauses from the clause_info data structure
% into the proc_info data structure. Each clause is marked
% with a list of the modes for which it applies, so that
% there can be different code to implement different modes
% of a predicate (e.g. sort). For each mode of the predicate,
% we select the clauses for that mode, disjoin them together,
% and save this in the proc_info.
%
:- pred copy_module_clauses_to_procs(list(pred_id)::in,
module_info::in, module_info::out) is det.
:- pred copy_clauses_to_proc(proc_id::in, clauses_info::in,
proc_info::in, proc_info::out) is det.
% Before copying the clauses to the procs, we need to add
% a default mode of `:- mode foo(in, in, ..., in) = out is det.'
% for functions that don't have an explicit mode declaration.
%
:- pred maybe_add_default_func_modes(list(pred_id)::in,
pred_table::in, pred_table::out) is det.
:- pred maybe_add_default_func_mode(pred_info::in, pred_info::out,
maybe(proc_id)::out) is det.
% After copying the clauses to the procs, we need to transform the
% procedures to introduce any required exists_casts..
%
:- pred introduce_exists_casts(list(pred_id)::in, module_info::in,
module_info::out) is det.
% This version is used by polymorphism.m.
%
:- pred introduce_exists_casts_proc(module_info::in, pred_info::in,
proc_info::in, proc_info::out) is det.
%-----------------------------------------------------------------------------%
%-----------------------------------------------------------------------------%
:- implementation.
:- import_module check_hlds.mode_util.
:- import_module check_hlds.purity.
:- import_module hlds.goal_util.
:- import_module hlds.hlds_data.
:- import_module hlds.hlds_goal.
:- import_module hlds.make_hlds.
:- import_module libs.compiler_util.
:- import_module libs.globals.
:- import_module mdbcomp.prim_data.
:- import_module parse_tree.prog_data.
:- import_module parse_tree.prog_mode.
:- import_module parse_tree.prog_type.
:- import_module parse_tree.prog_type_subst.
:- import_module assoc_list.
:- import_module bool.
:- import_module int.
:- import_module map.
:- import_module set.
:- import_module string.
:- import_module svmap.
:- import_module svvarset.
:- import_module term.
:- import_module varset.
%-----------------------------------------------------------------------------%
maybe_add_default_func_modes([], Preds, Preds).
maybe_add_default_func_modes([PredId | PredIds], Preds0, Preds) :-
map.lookup(Preds0, PredId, PredInfo0),
maybe_add_default_func_mode(PredInfo0, PredInfo, _),
map.det_update(Preds0, PredId, PredInfo, Preds1),
maybe_add_default_func_modes(PredIds, Preds1, Preds).
maybe_add_default_func_mode(PredInfo0, PredInfo, MaybeProcId) :-
pred_info_procedures(PredInfo0, Procs0),
PredOrFunc = pred_info_is_pred_or_func(PredInfo0),
(
%
% Is this a function with no modes?
%
PredOrFunc = function,
map.is_empty(Procs0)
->
%
% If so, add a default mode of
%
% :- mode foo(in, in, ..., in) = out is det.
%
% for this function. (N.B. functions which can
% fail must be explicitly declared as semidet.)
%
PredArity = pred_info_orig_arity(PredInfo0),
FuncArity = PredArity - 1,
in_mode(InMode),
out_mode(OutMode),
list.duplicate(FuncArity, InMode, FuncArgModes),
FuncRetMode = OutMode,
list.append(FuncArgModes, [FuncRetMode], PredArgModes),
Determinism = det,
pred_info_context(PredInfo0, Context),
MaybePredArgLives = no,
varset.init(InstVarSet),
% No inst_vars in default func mode.
add_new_proc(InstVarSet, PredArity, PredArgModes,
yes(PredArgModes), MaybePredArgLives, yes(Determinism),
Context, address_is_not_taken, PredInfo0, PredInfo, ProcId),
MaybeProcId = yes(ProcId)
;
PredInfo = PredInfo0,
MaybeProcId = no
).
copy_module_clauses_to_procs(PredIds, !ModuleInfo) :-
module_info_preds(!.ModuleInfo, PredTable0),
list.foldl(copy_pred_clauses_to_procs, PredIds, PredTable0, PredTable),
module_info_set_preds(PredTable, !ModuleInfo).
% For each mode of the given predicate, copy the clauses relevant
% to the mode and the current backend to the proc_info.
%
% This is not the only predicate in the compiler that does this task;
% the other is polymorphism.process_proc.
%
:- pred copy_pred_clauses_to_procs(pred_id::in,
pred_table::in, pred_table::out) is det.
copy_pred_clauses_to_procs(PredId, !PredTable) :-
map.lookup(!.PredTable, PredId, PredInfo0),
(
do_copy_clauses_to_procs(PredInfo0)
->
copy_clauses_to_procs(PredInfo0, PredInfo),
map.det_update(!.PredTable, PredId, PredInfo, !:PredTable)
;
true
).
:- pred do_copy_clauses_to_procs(pred_info::in) is semidet.
do_copy_clauses_to_procs(PredInfo) :-
% Don't process typeclass methods, because their proc_infos
% are generated already mode-correct.
pred_info_get_markers(PredInfo, PredMarkers),
\+ check_marker(PredMarkers, class_method).
:- pred copy_clauses_to_procs(pred_info::in, pred_info::out) is det.
copy_clauses_to_procs(!PredInfo) :-
pred_info_procedures(!.PredInfo, Procs0),
pred_info_clauses_info(!.PredInfo, ClausesInfo),
ProcIds = pred_info_all_non_imported_procids(!.PredInfo),
copy_clauses_to_procs_2(ProcIds, ClausesInfo, Procs0, Procs),
pred_info_set_procedures(Procs, !PredInfo).
:- pred copy_clauses_to_procs_2(list(proc_id)::in, clauses_info::in,
proc_table::in, proc_table::out) is det.
copy_clauses_to_procs_2([], _, !Procs).
copy_clauses_to_procs_2([ProcId | ProcIds], ClausesInfo, !Procs) :-
map.lookup(!.Procs, ProcId, Proc0),
copy_clauses_to_proc(ProcId, ClausesInfo, Proc0, Proc),
map.det_update(!.Procs, ProcId, Proc, !:Procs),
copy_clauses_to_procs_2(ProcIds, ClausesInfo, !Procs).
copy_clauses_to_proc(ProcId, ClausesInfo, !Proc) :-
ClausesInfo = clauses_info(VarSet0, _, _, VarTypes, HeadVars,
ClausesRep, RttiInfo, _),
get_clause_list(ClausesRep, Clauses),
select_matching_clauses(Clauses, ProcId, MatchingClauses),
get_clause_goals(MatchingClauses, GoalList),
( GoalList = [SingleGoal] ->
SingleGoal = SingleExpr - _,
( SingleExpr = foreign_proc(_, _, _, Args, ExtraArgs, _) ->
%
% Use the original variable names for the headvars
% of foreign_proc clauses, not the introduced
% `HeadVar.n' names.
%
VarSet = list.foldl(set_arg_names, Args, VarSet0),
expect(unify(ExtraArgs, []), this_file,
"copy_clauses_to_proc: extra_args")
;
VarSet = VarSet0
),
Goal = SingleGoal
;
VarSet = VarSet0,
%
% Convert the list of clauses into a disjunction,
% and construct a goal_info for the disjunction.
%
%
% We use the context of the first clause, unless
% there weren't any clauses at all, in which case
% we use the context of the mode declaration.
%
goal_info_init(GoalInfo0),
( GoalList = [FirstGoal | _] ->
FirstGoal = _ - FirstGoalInfo,
goal_info_get_context(FirstGoalInfo, Context)
;
proc_info_context(!.Proc, Context)
),
goal_info_set_context(Context, GoalInfo0, GoalInfo1),
%
% The non-local vars are just the head variables.
%
set.list_to_set(HeadVars, NonLocalVars),
goal_info_set_nonlocals(NonLocalVars, GoalInfo1, GoalInfo2),
%
% The disjunction is impure/semipure if any of the disjuncts
% is impure/semipure.
%
( contains_nonpure_goal(GoalList) ->
list.map(get_purity, GoalList, PurityList),
Purity = list.foldl(worst_purity, PurityList, purity_pure),
add_goal_info_purity_feature(Purity, GoalInfo2, GoalInfo)
;
GoalInfo2 = GoalInfo
),
Goal = disj(GoalList) - GoalInfo
),
proc_info_set_body(VarSet, VarTypes, HeadVars, Goal, RttiInfo, !Proc).
:- pred contains_nonpure_goal(list(hlds_goal)::in) is semidet.
contains_nonpure_goal([Goal | Goals]) :-
(
Goal = _ - GoalInfo,
\+ goal_info_is_pure(GoalInfo)
;
contains_nonpure_goal(Goals)
).
:- func set_arg_names(foreign_arg, prog_varset) = prog_varset.
set_arg_names(Arg, Vars0) = Vars :-
Var = foreign_arg_var(Arg),
MaybeNameMode = foreign_arg_maybe_name_mode(Arg),
(
MaybeNameMode = yes(Name - _),
varset.name_var(Vars0, Var, Name, Vars)
;
MaybeNameMode = no,
Vars = Vars0
).
:- pred get_purity(hlds_goal::in, purity::out) is det.
get_purity(_Goal - GoalInfo, Purity) :-
infer_goal_info_purity(GoalInfo, Purity).
:- pred select_matching_clauses(list(clause)::in, proc_id::in,
list(clause)::out) is det.
select_matching_clauses([], _, []).
select_matching_clauses([Clause | Clauses], ProcId, MatchingClauses) :-
Clause = clause(ProcIds, _, _, _),
% An empty list here means that the clause applies to all procs.
( ProcIds = [] ->
MatchingClauses = [Clause | MatchingClauses1]
; list.member(ProcId, ProcIds) ->
MatchingClauses = [Clause | MatchingClauses1]
;
MatchingClauses = MatchingClauses1
),
select_matching_clauses(Clauses, ProcId, MatchingClauses1).
:- pred get_clause_goals(list(clause)::in, list(hlds_goal)::out) is det.
get_clause_goals([], []).
get_clause_goals([Clause | Clauses], Goals) :-
get_clause_goals(Clauses, Goals1),
Clause = clause(_, Goal, _, _),
goal_to_disj_list(Goal, GoalList),
list.append(GoalList, Goals1, Goals).
%-----------------------------------------------------------------------------%
introduce_exists_casts(PredIds, !ModuleInfo) :-
module_info_preds(!.ModuleInfo, PredTable0),
list.foldl(introduce_exists_casts_pred(!.ModuleInfo), PredIds,
PredTable0, PredTable),
module_info_set_preds(PredTable, !ModuleInfo).
:- pred introduce_exists_casts_pred(module_info::in, pred_id::in,
pred_table::in, pred_table::out) is det.
introduce_exists_casts_pred(ModuleInfo, PredId, !PredTable) :-
map.lookup(!.PredTable, PredId, PredInfo0),
(
% Optimise the common case.
pred_info_get_existq_tvar_binding(PredInfo0, Subn),
\+ map.is_empty(Subn),
% Only process preds for which we copied clauses to procs.
do_copy_clauses_to_procs(PredInfo0)
->
pred_info_procedures(PredInfo0, Procs0),
ProcIds = pred_info_all_non_imported_procids(PredInfo0),
introduce_exists_casts_procs(ModuleInfo, PredInfo0, ProcIds,
Procs0, Procs),
pred_info_set_procedures(Procs, PredInfo0, PredInfo),
svmap.det_update(PredId, PredInfo, !PredTable)
;
true
).
:- pred introduce_exists_casts_procs(module_info::in, pred_info::in,
list(proc_id)::in, proc_table::in, proc_table::out) is det.
introduce_exists_casts_procs(_, _, [], !Procs).
introduce_exists_casts_procs(ModuleInfo, PredInfo, [ProcId | ProcIds],
!Procs) :-
map.lookup(!.Procs, ProcId, ProcInfo0),
introduce_exists_casts_proc(ModuleInfo, PredInfo, ProcInfo0, ProcInfo),
svmap.det_update(ProcId, ProcInfo, !Procs),
introduce_exists_casts_procs(ModuleInfo, PredInfo, ProcIds, !Procs).
introduce_exists_casts_proc(ModuleInfo, PredInfo, !ProcInfo) :-
pred_info_arg_types(PredInfo, ArgTypes),
pred_info_get_existq_tvar_binding(PredInfo, Subn),
pred_info_get_class_context(PredInfo, PredConstraints),
OrigArity = pred_info_orig_arity(PredInfo),
NumExtraHeadVars = list.length(ArgTypes) - OrigArity,
proc_info_varset(!.ProcInfo, VarSet0),
proc_info_vartypes(!.ProcInfo, VarTypes0),
proc_info_headvars(!.ProcInfo, HeadVars0),
proc_info_goal(!.ProcInfo, Body0),
proc_info_rtti_varmaps(!.ProcInfo, RttiVarMaps0),
proc_info_argmodes(!.ProcInfo, ArgModes),
(
list.split_list(NumExtraHeadVars, ArgTypes, ExtraArgTypes0,
OrigArgTypes0),
list.split_list(NumExtraHeadVars, HeadVars0, ExtraHeadVars0,
OrigHeadVars0),
list.split_list(NumExtraHeadVars, ArgModes, ExtraArgModes0,
OrigArgModes0)
->
ExtraArgTypes = ExtraArgTypes0,
OrigArgTypes = OrigArgTypes0,
ExtraHeadVars1 = ExtraHeadVars0,
OrigHeadVars1 = OrigHeadVars0,
ExtraArgModes = ExtraArgModes0,
OrigArgModes = OrigArgModes0
;
unexpected(this_file, "introduce_exists_casts_proc: split_list failed")
),
% Add exists_casts for any head vars which are existentially typed,
% and for which the type is statically bound inside the procedure. Subn
% represents which existential types are bound.
introduce_exists_casts_for_head(ModuleInfo, Subn, OrigArgTypes,
OrigArgModes, OrigHeadVars1, OrigHeadVars, VarSet0, VarSet1,
VarTypes0, VarTypes1, [], ExistsCastHeadGoals),
% Add exists_casts for any existential type_infos or typeclass_infos.
% We determine which of these are existential by looking at the mode.
%
% Currently we pass in ExternalTypes so that the external type of
% type_infos and typeclass_infos can be looked up. When the arguments
% of these two types are removed, we will no longer need to do this.
%
map.from_corresponding_lists(ExtraHeadVars1, ExtraArgTypes,
ExternalTypes),
ExistConstraints = PredConstraints ^ exist_constraints,
assoc_list.from_corresponding_lists(ExtraArgModes, ExtraHeadVars1,
ExtraModesAndVars),
introduce_exists_casts_extra(ModuleInfo, ExternalTypes, Subn,
ExistConstraints, ExtraModesAndVars, ExtraHeadVars, VarSet1, VarSet,
VarTypes1, VarTypes, RttiVarMaps0, RttiVarMaps,
[], ExistsCastExtraGoals),
Body0 = _ - GoalInfo0,
goal_to_conj_list(Body0, Goals0),
Goals = Goals0 ++ ExistsCastHeadGoals ++ ExistsCastExtraGoals,
HeadVars = ExtraHeadVars ++ OrigHeadVars,
set.list_to_set(HeadVars, NonLocals),
goal_info_set_nonlocals(NonLocals, GoalInfo0, GoalInfo),
Body = conj(plain_conj, Goals) - GoalInfo,
proc_info_set_body(VarSet, VarTypes, HeadVars, Body, RttiVarMaps,
!ProcInfo).
:- pred introduce_exists_casts_for_head(module_info::in, tsubst::in,
list(mer_type)::in, list(mer_mode)::in, list(prog_var)::in,
list(prog_var)::out, prog_varset::in, prog_varset::out,
vartypes::in, vartypes::out, list(hlds_goal)::in, list(hlds_goal)::out)
is det.
introduce_exists_casts_for_head(ModuleInfo, Subn, ArgTypes, ArgModes,
!HeadVars, !VarSet, !VarTypes, !ExtraGoals) :-
(
ArgTypes = [],
ArgModes = [],
!.HeadVars = []
->
true
;
ArgTypes = [ArgType | ArgTypesRest],
ArgModes = [ArgMode | ArgModesRest],
!.HeadVars = [HeadVar0 | HeadVarsRest0]
->
introduce_exists_casts_for_head(ModuleInfo, Subn, ArgTypesRest,
ArgModesRest, HeadVarsRest0, HeadVarsRest, !VarSet, !VarTypes,
!ExtraGoals),
introduce_exists_casts_for_arg(ModuleInfo, Subn, ArgType, ArgMode,
HeadVar0, HeadVar, !VarSet, !VarTypes, !ExtraGoals),
!:HeadVars = [HeadVar | HeadVarsRest]
;
unexpected(this_file, "introduce_exists_casts_for_head: " ++
"length mismatch")
).
:- pred introduce_exists_casts_for_arg(module_info::in, tsubst::in,
mer_type::in, mer_mode::in, prog_var::in, prog_var::out,
prog_varset::in, prog_varset::out, vartypes::in, vartypes::out,
list(hlds_goal)::in, list(hlds_goal)::out) is det.
introduce_exists_casts_for_arg(ModuleInfo, Subn, ExternalType, ArgMode,
HeadVar0, HeadVar, !VarSet, !VarTypes, !ExtraGoals) :-
apply_rec_subst_to_type(Subn, ExternalType, InternalType),
(
% Add an exists_cast for the head variable if its type
% inside the procedure is different from its type at the
% interface.
InternalType \= ExternalType
->
term.context_init(Context),
svmap.det_update(HeadVar0, InternalType, !VarTypes),
make_new_exist_cast_var(HeadVar0, HeadVar, !VarSet),
svmap.det_insert(HeadVar, ExternalType, !VarTypes),
mode_get_insts(ModuleInfo, ArgMode, _, Inst),
generate_cast(exists_cast, HeadVar0, HeadVar, Inst, Inst, Context,
ExtraGoal),
!:ExtraGoals = [ExtraGoal | !.ExtraGoals]
;
HeadVar = HeadVar0
).
:- pred introduce_exists_casts_extra(module_info::in, vartypes::in, tsubst::in,
list(prog_constraint)::in, assoc_list(mer_mode, prog_var)::in,
list(prog_var)::out, prog_varset::in, prog_varset::out,
vartypes::in, vartypes::out, rtti_varmaps::in, rtti_varmaps::out,
list(hlds_goal)::in, list(hlds_goal)::out) is det.
introduce_exists_casts_extra(_, _, _, ExistConstraints, [], [], !VarSet,
!VarTypes, !RttiVarMaps, !ExtraGoals) :-
(
ExistConstraints = []
;
ExistConstraints = [_ | _],
unexpected(this_file, "introduce_exists_casts_extra: length mismatch")
).
introduce_exists_casts_extra(ModuleInfo, ExternalTypes, Subn,
ExistConstraints0, [ModeAndVar | ModesAndVars], [Var | Vars],
!VarSet, !VarTypes, !RttiVarMaps, !ExtraGoals) :-
ModeAndVar = ArgMode - Var0,
(
mode_is_output(ModuleInfo, ArgMode)
->
% Update the type of this variable. This only needs to be done
% because type_info/1 and typeclass_info/1 have types in their
% respective arguments.
%
map.lookup(ExternalTypes, Var0, ExternalType),
apply_rec_subst_to_type(Subn, ExternalType, InternalType),
svmap.det_update(Var0, InternalType, !VarTypes),
% Create the exists_cast goal.
%
term.context_init(Context),
make_new_exist_cast_var(Var0, Var, !VarSet),
svmap.det_insert(Var, ExternalType, !VarTypes),
generate_cast(exists_cast, Var0, Var, Context, ExtraGoal),
!:ExtraGoals = [ExtraGoal | !.ExtraGoals],
% Update the rtti_varmaps. The old variable needs to have the
% substitution applied to its type/constraint. The new variable
% needs to be associated with the unsubstituted type/constraint.
%
rtti_varmaps_var_info(!.RttiVarMaps, Var0, VarInfo),
(
VarInfo = type_info_var(TypeInfoType0),
% For type_infos, the old variable needs to have the substitution
% applied to its type, and the new variable needs to be associated
% with the unsubstituted type.
apply_rec_subst_to_type(Subn, TypeInfoType0, TypeInfoType),
rtti_set_type_info_type(Var0, TypeInfoType, !RttiVarMaps),
rtti_det_insert_type_info_type(Var, TypeInfoType0, !RttiVarMaps),
ExistConstraints = ExistConstraints0
;
VarInfo = typeclass_info_var(_),
% For typeclass_infos, the constraint associated with the old
% variable was derived from the constraint map, so all binding
% and improvement has been applied. The new variable needs to
% be associated with the corresponding existential head constraint,
% so we pop one off the front of the list.
(
ExistConstraints0 = [ExistConstraint | ExistConstraints]
;
ExistConstraints0 = [],
unexpected(this_file, "introduce_exists_casts_extra: " ++
"missing constraint")
),
rtti_det_insert_typeclass_info_var(ExistConstraint, Var,
!RttiVarMaps),
% We also need to ensure that all type variables in the constraint
% have a location recorded, so we insert a location now if there
% is not already one.
ExistConstraint = constraint(_, ConstraintArgs),
maybe_add_type_info_locns(ConstraintArgs, Var, 1, !RttiVarMaps)
;
VarInfo = non_rtti_var,
unexpected(this_file, "introduce_exists_casts_extra: " ++
"rtti_varmaps info not found")
)
;
Var = Var0,
ExistConstraints = ExistConstraints0
),
introduce_exists_casts_extra(ModuleInfo, ExternalTypes, Subn,
ExistConstraints, ModesAndVars, Vars, !VarSet, !VarTypes,
!RttiVarMaps, !ExtraGoals).
:- pred maybe_add_type_info_locns(list(mer_type)::in, prog_var::in, int::in,
rtti_varmaps::in, rtti_varmaps::out) is det.
maybe_add_type_info_locns([], _, _, !RttiVarMaps).
maybe_add_type_info_locns([Arg | Args], Var, Num, !RttiVarMaps) :-
(
Arg = variable(TVar, _),
\+ rtti_search_type_info_locn(!.RttiVarMaps, TVar, _)
->
Locn = typeclass_info(Var, Num),
rtti_det_insert_type_info_locn(TVar, Locn, !RttiVarMaps)
;
true
),
maybe_add_type_info_locns(Args, Var, Num + 1, !RttiVarMaps).
:- pred make_new_exist_cast_var(prog_var::in, prog_var::out,
prog_varset::in, prog_varset::out) is det.
make_new_exist_cast_var(InternalVar, ExternalVar, !VarSet) :-
svvarset.new_var(ExternalVar, !VarSet),
varset.lookup_name(!.VarSet, InternalVar, InternalName),
string.append("ExistQ", InternalName, ExternalName),
svvarset.name_var(ExternalVar, ExternalName, !VarSet).
%-----------------------------------------------------------------------------%
:- func this_file = string.
this_file = "clause_to_proc.m".
%-----------------------------------------------------------------------------%
:- end_module check_hlds.clause_to_proc.
%-----------------------------------------------------------------------------%