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295415090e79c32f73f83bd8b60bb32198d87206
mercury/compiler/unique_modes.m
Zoltan Somogyi 295415090e Convert almost all remaining modules in the compiler to use 
Estimated hours taken: 6
Branches: main

compiler/*.m:
	Convert almost all remaining modules in the compiler to use
	"$module, $pred" instead of "this_file" in error messages.

	In a few cases, the old error message was misleading, since it
	contained an incorrect, out-of-date or cut-and-pasted predicate name.

tests/invalid/unresolved_overloading.err_exp:
	Update an expected output containing an updated error message.
2011-05-23 05:08:24 +00:00

1018 lines
42 KiB
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%-----------------------------------------------------------------------------%
% vim: ft=mercury ts=4 sw=4 et
%-----------------------------------------------------------------------------%
% Copyright (C) 1996-2011 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.
%-----------------------------------------------------------------------------%
%
% File: unique_modes.m.
% Main author: fjh
%
% This module checks that variables with a unique mode (as opposed to a
% mostly-unique mode) really are unique, and not nondet live - i.e. that
% they cannot be referenced on backtracking. (Actually the term "nondet live"
% is a bit of a misnomer, because really we are just interested in whether
% something can be referenced on backtracking, and this can occur after
% backtracking in semidet code too, not just in nondet code.)
%
% Basically we just traverse each goal, keeping track of which variables are
% nondet live. At each procedure call, we check that any arguments whose
% initial insts are required to be unique are not nondet live. If they are,
% we first try selecting a different mode of the same predicate, and if that
% fails, then we report an error message.
%
% Variables can become nondet live in several places: in negations, in the
% conditions of if-then-elses, in disjunctions, and at nondet calls. These are
% the only places at which we can resume execution after backtracking.
%
% XXX We currently make the conservative assumption that any non-local variable
% in a disjunction or nondet call is nondet-live - and stays nondet-live.
%
%-----------------------------------------------------------------------------%
:- module check_hlds.unique_modes.
:- interface.
:- import_module check_hlds.mode_info.
:- import_module hlds.
:- import_module hlds.hlds_goal.
:- import_module hlds.hlds_module.
:- import_module hlds.hlds_pred.
:- import_module parse_tree.
:- import_module parse_tree.error_util.
:- import_module parse_tree.prog_data.
:- import_module bool.
:- import_module list.
:- import_module set.
%-----------------------------------------------------------------------------%
% Check every predicate in a module.
%
:- pred unique_modes_check_module(module_info::in, module_info::out,
list(error_spec)::out) is det.
% Just check a single procedure.
%
:- pred unique_modes_check_proc(proc_id::in, pred_id::in,
module_info::in, module_info::out, bool::out, list(error_spec)::out)
is det.
% Just check a single goal.
%
:- pred unique_modes_check_goal(hlds_goal::in, hlds_goal::out,
mode_info::in, mode_info::out) is det.
% Prepare for checking a disjunct in a disjunction.
%
:- pred prepare_for_disjunct(hlds_goal::in, determinism::in, set(prog_var)::in,
mode_info::in, mode_info::out) is det.
% Make all nondet-live variables whose current inst
% is `unique' become `mostly_unique'.
%
:- pred make_all_nondet_live_vars_mostly_uniq(mode_info::in, mode_info::out)
is det.
%-----------------------------------------------------------------------------%
%-----------------------------------------------------------------------------%
:- implementation.
:- import_module check_hlds.inst_match.
:- import_module check_hlds.inst_util.
:- import_module check_hlds.mode_debug.
:- import_module check_hlds.mode_errors.
:- import_module check_hlds.mode_util.
:- import_module check_hlds.modecheck_call.
:- import_module check_hlds.modecheck_unify.
:- import_module check_hlds.modecheck_util.
:- import_module check_hlds.modes.
:- import_module hlds.instmap.
:- import_module mdbcomp.
:- import_module mdbcomp.prim_data.
:- import_module parse_tree.prog_mode.
:- import_module bag.
:- import_module int.
:- import_module map.
:- import_module maybe.
:- import_module pair.
:- import_module require.
:- import_module string.
:- import_module term.
%-----------------------------------------------------------------------------%
unique_modes_check_module(!ModuleInfo, Specs) :-
check_pred_modes(check_unique_modes, may_change_called_proc,
!ModuleInfo, _SafeToContinue, Specs).
unique_modes_check_proc(ProcId, PredId, !ModuleInfo, Changed, Specs) :-
modecheck_proc_general(ProcId, PredId, check_unique_modes,
may_change_called_proc, !ModuleInfo, Specs, Changed).
unique_modes_check_goal(Goal0, Goal, !ModeInfo) :-
Goal0 = hlds_goal(GoalExpr0, GoalInfo0),
Context = goal_info_get_context(GoalInfo0),
term.context_init(EmptyContext),
( Context = EmptyContext ->
true
;
mode_info_set_context(Context, !ModeInfo)
),
( goal_info_has_feature(GoalInfo0, feature_duplicated_for_switch) ->
mode_info_get_in_dupl_for_switch(!.ModeInfo, InDuplForSwitch),
mode_info_set_in_dupl_for_switch(in_dupl_for_switch, !ModeInfo),
unique_modes_check_goal_2(GoalExpr0, GoalInfo0, Goal, !ModeInfo),
mode_info_set_in_dupl_for_switch(InDuplForSwitch, !ModeInfo)
;
unique_modes_check_goal_2(GoalExpr0, GoalInfo0, Goal, !ModeInfo)
).
:- pred unique_modes_check_goal_2(hlds_goal_expr::in, hlds_goal_info::in,
hlds_goal::out, mode_info::in, mode_info::out) is det.
:- pragma inline(unique_modes_check_goal_2/5).
unique_modes_check_goal_2(GoalExpr0, GoalInfo0, Goal, !ModeInfo) :-
mode_info_get_instmap(!.ModeInfo, InstMap0),
% Grab the original bag of nondet-live vars.
mode_info_get_nondet_live_vars(!.ModeInfo, NondetLiveVars0),
% If the goal is not nondet, then nothing is nondet-live, so reset the bag
% of nondet-live vars to be empty.
Detism = goal_info_get_determinism(GoalInfo0),
( determinism_components(Detism, _, at_most_many) ->
true
;
mode_info_set_nondet_live_vars(bag.init, !ModeInfo)
),
unique_modes_check_goal_expr(GoalExpr0, GoalInfo0, GoalExpr, !ModeInfo),
% Restore the original bag of nondet-live vars.
mode_info_set_nondet_live_vars(NondetLiveVars0, !ModeInfo),
% Grab the final instmap, compute the change in insts over this goal,
% and save that instmap_delta in the goal_info.
compute_goal_instmap_delta(InstMap0, GoalExpr, GoalInfo0, GoalInfo,
!ModeInfo),
Goal = hlds_goal(GoalExpr, GoalInfo).
make_all_nondet_live_vars_mostly_uniq(ModeInfo0, ModeInfo) :-
mode_info_get_instmap(ModeInfo0, FullInstMap0),
( instmap_is_reachable(FullInstMap0) ->
instmap_vars_list(FullInstMap0, AllVars),
select_nondet_live_vars(AllVars, ModeInfo0, NondetLiveVars),
make_var_list_mostly_uniq(NondetLiveVars, ModeInfo0, ModeInfo)
;
ModeInfo = ModeInfo0
).
:- pred select_live_vars(list(prog_var)::in, mode_info::in,
list(prog_var)::out) is det.
select_live_vars([], _, []).
select_live_vars([Var|Vars], ModeInfo, LiveVars) :-
( mode_info_var_is_live(ModeInfo, Var, is_live) ->
select_live_vars(Vars, ModeInfo, LiveVars1),
LiveVars = [Var | LiveVars1]
;
select_live_vars(Vars, ModeInfo, LiveVars)
).
:- pred select_nondet_live_vars(list(prog_var)::in, mode_info::in,
list(prog_var)::out) is det.
select_nondet_live_vars([], _, []).
select_nondet_live_vars([Var|Vars], ModeInfo, NondetLiveVars) :-
( mode_info_var_is_nondet_live(ModeInfo, Var, is_live) ->
select_nondet_live_vars(Vars, ModeInfo, NondetLiveVars1),
NondetLiveVars = [Var | NondetLiveVars1]
;
select_nondet_live_vars(Vars, ModeInfo, NondetLiveVars)
).
% Given a list of variables, a delta instmap, and a mode_info, select all
% the variables whose inst changed in the delta instmap (other than
% changes which just add information, e.g. `ground -> bound(42)'.)
%
:- pred select_changed_inst_vars(list(prog_var)::in, instmap_delta::in,
mode_info::in, list(prog_var)::out) is det.
select_changed_inst_vars([], _DeltaInstMap, _ModeInfo, []).
select_changed_inst_vars([Var | Vars], DeltaInstMap, ModeInfo, ChangedVars) :-
mode_info_get_module_info(ModeInfo, ModuleInfo),
mode_info_get_instmap(ModeInfo, InstMap0),
instmap_lookup_var(InstMap0, Var, Inst0),
mode_info_get_var_types(ModeInfo, VarTypes),
map.lookup(VarTypes, Var, Type),
(
instmap_delta_is_reachable(DeltaInstMap),
instmap_delta_search_var(DeltaInstMap, Var, Inst),
\+ inst_matches_final_typed(Inst, Inst0, Type, ModuleInfo)
->
select_changed_inst_vars(Vars, DeltaInstMap, ModeInfo, ChangedVars1),
ChangedVars = [Var | ChangedVars1]
;
select_changed_inst_vars(Vars, DeltaInstMap, ModeInfo, ChangedVars)
).
:- pred make_var_list_mostly_uniq(list(prog_var)::in,
mode_info::in, mode_info::out) is det.
make_var_list_mostly_uniq([], !ModeInfo).
make_var_list_mostly_uniq([Var | Vars], !ModeInfo) :-
make_var_mostly_uniq(Var, !ModeInfo),
make_var_list_mostly_uniq(Vars, !ModeInfo).
:- pred make_var_mostly_uniq(prog_var::in,
mode_info::in, mode_info::out) is det.
make_var_mostly_uniq(Var, !ModeInfo) :-
mode_info_get_instmap(!.ModeInfo, InstMap0),
mode_info_get_module_info(!.ModeInfo, ModuleInfo0),
(
% Only variables which are `unique' need to be changed.
instmap_is_reachable(InstMap0),
instmap_vars_list(InstMap0, Vars),
list.member(Var, Vars),
instmap_lookup_var(InstMap0, Var, Inst0),
inst_expand(ModuleInfo0, Inst0, Inst1),
( Inst1 = ground(unique, _)
; Inst1 = bound(unique, _)
; Inst1 = any(unique, _)
)
->
make_mostly_uniq_inst(Inst0, Inst, ModuleInfo0, ModuleInfo),
mode_info_set_module_info(ModuleInfo, !ModeInfo),
instmap_set_var(Var, Inst, InstMap0, InstMap),
mode_info_set_instmap(InstMap, !ModeInfo)
;
true
).
%-----------------------------------------------------------------------------%
:- pred unique_modes_check_goal_expr(hlds_goal_expr::in, hlds_goal_info::in,
hlds_goal_expr::out, mode_info::in, mode_info::out) is det.
unique_modes_check_goal_expr(GoalExpr0, GoalInfo0, GoalExpr, !ModeInfo) :-
% XXX The predicates we call here should have their definitions
% in the same order as this switch.
(
GoalExpr0 = unify(LHS0, RHS0, _UniModes0, Unification0, UnifyContext0),
unique_modes_check_goal_unify(LHS0, RHS0, Unification0, UnifyContext0,
GoalInfo0, GoalExpr, !ModeInfo)
;
GoalExpr0 = plain_call(PredId0, ProcId0, ArgVars0, Builtin0,
MaybeUnifyContext0, SymName0),
unique_modes_check_goal_plain_call(PredId0, ProcId0, ArgVars0,
Builtin0, MaybeUnifyContext0, SymName0, GoalInfo0, GoalExpr,
!ModeInfo)
;
GoalExpr0 = generic_call(GenericCall0, ArgVars0, ArgModes0, Detism0),
unique_modes_check_goal_generic_call(GenericCall0, ArgVars0, ArgModes0,
Detism0, GoalExpr, !ModeInfo)
;
GoalExpr0 = call_foreign_proc(Attributes0, PredId0, ProcId0,
Args0, ExtraArgs0, MaybeTraceRuntimeCond0, PragmaCode0),
unique_modes_check_goal_call_foreign_proc(Attributes0,
PredId0, ProcId0, Args0, ExtraArgs0, MaybeTraceRuntimeCond0,
PragmaCode0, GoalInfo0, GoalExpr, !ModeInfo)
;
GoalExpr0 = conj(GoalType0, Goals0),
unique_modes_check_goal_conj(GoalType0, Goals0, GoalExpr,
!ModeInfo)
;
GoalExpr0 = disj(Goals0),
unique_modes_check_goal_disj(Goals0, GoalInfo0, GoalExpr,
!ModeInfo)
;
GoalExpr0 = switch(Var0, CanFail0, Cases0),
unique_modes_check_goal_switch(Var0, CanFail0, Cases0, GoalInfo0,
GoalExpr, !ModeInfo)
;
GoalExpr0 = if_then_else(Vars0, Cond0, Then0, Else0),
unique_modes_check_goal_if_then_else(Vars0, Cond0, Then0, Else0,
GoalInfo0, GoalExpr, !ModeInfo)
;
GoalExpr0 = negation(SubGoal0),
unique_modes_check_goal_negation(SubGoal0, GoalInfo0, GoalExpr,
!ModeInfo)
;
GoalExpr0 = scope(Reason0, SubGoal0),
unique_modes_check_goal_scope(Reason0, SubGoal0, GoalExpr, !ModeInfo)
;
GoalExpr0 = shorthand(ShortHand0),
(
ShortHand0 = atomic_goal(GoalType, Outer, Inner, MaybeOutputVars,
MainGoal0, OrElseGoals0, OrElseInners0),
unique_modes_check_goal_atomic_goal(GoalType, Outer, Inner,
MaybeOutputVars, MainGoal0, OrElseGoals0, OrElseInners0,
GoalInfo0, GoalExpr, !ModeInfo)
;
ShortHand0 = try_goal(MaybeIO, ResultVar, SubGoal0),
mode_checkpoint(enter, "try", !ModeInfo),
unique_modes_check_goal(SubGoal0, SubGoal, !ModeInfo),
ShortHand = try_goal(MaybeIO, ResultVar, SubGoal),
GoalExpr = shorthand(ShortHand),
mode_checkpoint(exit, "try", !ModeInfo)
;
ShortHand0 = bi_implication(_, _),
% These should have been expanded out by now.
unexpected($module, $pred, "bi_implication")
)
).
:- pred unique_modes_check_goal_conj(conj_type::in, list(hlds_goal)::in,
hlds_goal_expr::out, mode_info::in, mode_info::out) is det.
unique_modes_check_goal_conj(ConjType, Goals0, GoalExpr, !ModeInfo) :-
mode_checkpoint(enter, "*conj", !ModeInfo),
(
Goals0 = [],
% For efficiency, optimize common case.
Goals = []
;
Goals0 = [_ | _],
mode_info_add_goals_live_vars(ConjType, Goals0, !ModeInfo),
unique_modes_check_conj(ConjType, Goals0, Goals, !ModeInfo)
),
GoalExpr = conj(ConjType, Goals),
mode_checkpoint(exit, "*conj", !ModeInfo).
:- pred unique_modes_check_goal_disj(list(hlds_goal)::in,
hlds_goal_info::in, hlds_goal_expr::out,
mode_info::in, mode_info::out) is det.
unique_modes_check_goal_disj(Goals0, GoalInfo0, GoalExpr, !ModeInfo) :-
mode_checkpoint(enter, "disj", !ModeInfo),
(
Goals0 = [],
Goals = [],
instmap.init_unreachable(InstMap),
mode_info_set_instmap(InstMap, !ModeInfo)
;
Goals0 = [_ | _],
% If the disjunction creates a choice point (i.e. is model_non), then
% mark all the variables which are live at the start of the disjunction
% and whose inst is `unique' as instead being only `mostly_unique',
% since those variables may be needed again after we backtrack to that
% choice point and resume forward execution again.
%
% Note: for model_det or model_semi disjunctions, we may do some
% "shallow" backtracking from semidet disjuncts. But we handle that
% separately for each disjunct, in unique_modes_check_disj.
NonLocals = goal_info_get_nonlocals(GoalInfo0),
Determinism = goal_info_get_determinism(GoalInfo0),
% Does this disjunction create a choice point?
( determinism_components(Determinism, _, at_most_many) ->
mode_info_add_live_vars(NonLocals, !ModeInfo),
make_all_nondet_live_vars_mostly_uniq(!ModeInfo),
mode_info_remove_live_vars(NonLocals, !ModeInfo)
;
true
),
% Now just modecheck each disjunct in turn, and then
% merge the resulting instmaps.
unique_modes_check_disj(Goals0, Determinism, NonLocals, Goals,
InstMaps, !ModeInfo),
instmap_merge(NonLocals, InstMaps, merge_disj, !ModeInfo)
),
GoalExpr = disj(Goals),
mode_checkpoint(exit, "disj", !ModeInfo).
:- pred unique_modes_check_goal_if_then_else(list(prog_var)::in,
hlds_goal::in, hlds_goal::in, hlds_goal::in,
hlds_goal_info::in, hlds_goal_expr::out,
mode_info::in, mode_info::out) is det.
unique_modes_check_goal_if_then_else(Vars, Cond0, Then0, Else0, GoalInfo0,
GoalExpr, !ModeInfo) :-
mode_checkpoint(enter, "if-then-else", !ModeInfo),
NonLocals = goal_info_get_nonlocals(GoalInfo0),
CondVars = goal_get_nonlocals(Cond0),
ThenVars = goal_get_nonlocals(Then0),
ElseVars = goal_get_nonlocals(Else0),
mode_info_get_instmap(!.ModeInfo, InstMap0),
mode_info_lock_vars(var_lock_if_then_else, NonLocals, !ModeInfo),
% At this point, we should set the inst of any `unique' variables which
% occur in the condition and which are live to `mostly_unique'. However,
% if a variable's inst was unchanged over the condition (i.e. it remains
% `unique' on exit from the condition), then it is safe to leave it as
% `unique' on entry to the condition. The only case we need to set it
% to `mostly_unique' is if the condition would clobber it.
%
% XXX Actually that is not true; the code below does the wrong thing
% for examples such as this one:
%
% :- mode p(di).
% p(Var) :-
% (if
% (if semidet_succeed then
% clobber(Var), fail
% else
% true
% )
% then
% blah
% else
% use(Var)
% ).
mode_info_add_live_vars(ElseVars, !ModeInfo),
set.to_sorted_list(CondVars, CondVarList),
select_live_vars(CondVarList, !.ModeInfo, CondLiveVars),
Cond0 = hlds_goal(_, CondInfo0),
CondDeltaInstMap0 = goal_info_get_instmap_delta(CondInfo0),
select_changed_inst_vars(CondLiveVars, CondDeltaInstMap0, !.ModeInfo,
ChangedVars),
make_var_list_mostly_uniq(ChangedVars, !ModeInfo),
mode_info_remove_live_vars(ElseVars, !ModeInfo),
mode_info_add_live_vars(ThenVars, !ModeInfo),
unique_modes_check_goal(Cond0, Cond, !ModeInfo),
mode_info_remove_live_vars(ThenVars, !ModeInfo),
mode_info_unlock_vars(var_lock_if_then_else, NonLocals, !ModeInfo),
mode_info_get_instmap(!.ModeInfo, InstMapCond),
( instmap_is_reachable(InstMapCond) ->
unique_modes_check_goal(Then0, Then, !ModeInfo),
mode_info_get_instmap(!.ModeInfo, InstMapThen)
;
% We should not mode-analyse the goal, since it is unreachable.
% Instead we optimize the goal away, so that later passes
% won't complain about it not having unique mode information.
Then = true_goal,
InstMapThen = InstMapCond
),
mode_info_set_instmap(InstMap0, !ModeInfo),
unique_modes_check_goal(Else0, Else, !ModeInfo),
mode_info_get_instmap(!.ModeInfo, InstMapElse),
mode_info_set_instmap(InstMap0, !ModeInfo),
instmap_merge(NonLocals, [InstMapThen, InstMapElse], merge_if_then_else,
!ModeInfo),
GoalExpr = if_then_else(Vars, Cond, Then, Else),
mode_checkpoint(exit, "if-then-else", !ModeInfo).
:- pred unique_modes_check_goal_negation(hlds_goal::in,
hlds_goal_info::in, hlds_goal_expr::out,
mode_info::in, mode_info::out) is det.
unique_modes_check_goal_negation(SubGoal0, GoalInfo0, GoalExpr, !ModeInfo) :-
mode_checkpoint(enter, "not", !ModeInfo),
mode_info_get_instmap(!.ModeInfo, InstMap0),
% We need to mark all the variables which are live after the negation
% as nondet-live for the negated goal, since if the negated goal fails,
% then the negation will succeed, and so these variables can be accessed
% again after backtracking.
NonLocals = goal_info_get_nonlocals(GoalInfo0),
set.to_sorted_list(NonLocals, NonLocalsList),
select_live_vars(NonLocalsList, !.ModeInfo, LiveNonLocals),
make_var_list_mostly_uniq(LiveNonLocals, !ModeInfo),
% But nothing is forward-live for the negated goal, since if the goal
% succeeds then execution will immediately backtrack. So we need to set
% the live variables set to empty here.
mode_info_get_live_vars(!.ModeInfo, LiveVars0),
mode_info_set_live_vars(bag.init, !ModeInfo),
% We need to lock the non-local variables, to ensure that the negation
% does not bind them.
mode_info_lock_vars(var_lock_negation, NonLocals, !ModeInfo),
unique_modes_check_goal(SubGoal0, SubGoal, !ModeInfo),
mode_info_unlock_vars(var_lock_negation, NonLocals, !ModeInfo),
mode_info_set_live_vars(LiveVars0, !ModeInfo),
mode_info_set_instmap(InstMap0, !ModeInfo),
GoalExpr = negation(SubGoal),
mode_checkpoint(exit, "not", !ModeInfo).
:- pred unique_modes_check_goal_scope(scope_reason::in, hlds_goal::in,
hlds_goal_expr::out, mode_info::in, mode_info::out) is det.
unique_modes_check_goal_scope(Reason, SubGoal0, GoalExpr, !ModeInfo) :-
mode_checkpoint(enter, "scope", !ModeInfo),
( Reason = from_ground_term(TermVar, from_ground_term_construct) ->
mode_info_var_is_live(!.ModeInfo, TermVar, LiveTermVar),
(
LiveTermVar = is_live,
% The subgoal was left in its final state during (non-unique) mode
% checking. All we need to do here is to add the relevant
% information in the goal to ModeInfo.
SubGoal = SubGoal0,
SubGoal = hlds_goal(_, SubGoalInfo),
InstMapDelta = goal_info_get_instmap_delta(SubGoalInfo),
( instmap_delta_search_var(InstMapDelta, TermVar, TermVarInst) ->
mode_info_get_instmap(!.ModeInfo, InstMap0),
instmap_set_var(TermVar, TermVarInst, InstMap0, InstMap),
mode_info_set_instmap(InstMap, !ModeInfo)
;
unexpected($module, $pred, "bad InstMapDelta")
),
GoalExpr = scope(Reason, SubGoal)
;
LiveTermVar = is_dead,
% The term constructed by the scope is not used anywhere.
GoalExpr = conj(plain_conj, [])
)
;
unique_modes_check_goal(SubGoal0, SubGoal, !ModeInfo),
GoalExpr = scope(Reason, SubGoal)
),
mode_checkpoint(exit, "scope", !ModeInfo).
:- pred unique_modes_check_goal_generic_call(generic_call::in,
list(prog_var)::in, list(mer_mode)::in, determinism::in,
hlds_goal_expr::out, mode_info::in, mode_info::out) is det.
unique_modes_check_goal_generic_call(GenericCall, ArgVars, Modes, Detism,
GoalExpr, !ModeInfo) :-
mode_checkpoint(enter, "generic_call", !ModeInfo),
hlds_goal.generic_call_id(GenericCall, CallId),
mode_info_set_call_context(call_context_call(CallId), !ModeInfo),
( determinism_components(Detism, _, at_most_zero) ->
NeverSucceeds = yes
;
NeverSucceeds = no
),
(
GenericCall = higher_order(_, _, _, _),
ArgOffset = 1
;
% Class method calls are introduced by the compiler
% and should be mode correct.
GenericCall = class_method(_, _, _, _),
ArgOffset = 0
;
GenericCall = event_call(_),
ArgOffset = 0
;
% Casts are introduced by the compiler and should be mode correct.
GenericCall = cast(_),
ArgOffset = 0
),
unique_modes_check_call_modes(ArgVars, Modes, ArgOffset, Detism,
NeverSucceeds, !ModeInfo),
GoalExpr = generic_call(GenericCall, ArgVars, Modes, Detism),
mode_info_unset_call_context(!ModeInfo),
mode_checkpoint(exit, "generic_call", !ModeInfo).
:- pred unique_modes_check_goal_plain_call(pred_id::in, proc_id::in,
list(prog_var)::in, builtin_state::in, maybe(call_unify_context)::in,
sym_name::in, hlds_goal_info::in, hlds_goal_expr::out,
mode_info::in, mode_info::out) is det.
unique_modes_check_goal_plain_call(PredId, ProcId0, ArgVars, Builtin,
MaybeUnifyContext, PredName, GoalInfo0, GoalExpr, !ModeInfo) :-
PredNameString = sym_name_to_string(PredName),
string.append("call ", PredNameString, CallString),
mode_checkpoint(enter, CallString, !ModeInfo),
mode_info_get_call_id(!.ModeInfo, PredId, CallId),
mode_info_set_call_context(call_context_call(plain_call_id(CallId)),
!ModeInfo),
unique_modes_check_call(PredId, ProcId0, ArgVars, GoalInfo0, ProcId,
!ModeInfo),
GoalExpr = plain_call(PredId, ProcId, ArgVars, Builtin, MaybeUnifyContext,
PredName),
mode_info_unset_call_context(!ModeInfo),
mode_checkpoint(exit, "call", !ModeInfo).
:- pred unique_modes_check_goal_unify(prog_var::in, unify_rhs::in,
unification::in, unify_context::in,
hlds_goal_info::in, hlds_goal_expr::out,
mode_info::in, mode_info::out) is det.
unique_modes_check_goal_unify(LHS0, RHS0, Unification0, UnifyContext,
GoalInfo0, GoalExpr, !ModeInfo) :-
mode_checkpoint(enter, "unify", !ModeInfo),
mode_info_set_call_context(call_context_unify(UnifyContext), !ModeInfo),
modecheck_unification(LHS0, RHS0, Unification0, UnifyContext, GoalInfo0,
GoalExpr, !ModeInfo),
mode_info_unset_call_context(!ModeInfo),
mode_checkpoint(exit, "unify", !ModeInfo).
:- pred unique_modes_check_goal_switch(prog_var::in, can_fail::in,
list(case)::in, hlds_goal_info::in, hlds_goal_expr::out,
mode_info::in, mode_info::out) is det.
unique_modes_check_goal_switch(Var, CanFail, Cases0, GoalInfo0, GoalExpr,
!ModeInfo) :-
mode_checkpoint(enter, "switch", !ModeInfo),
(
Cases0 = [],
Cases = [],
instmap.init_unreachable(InstMap),
mode_info_set_instmap(InstMap, !ModeInfo)
;
Cases0 = [_ | _],
NonLocals = goal_info_get_nonlocals(GoalInfo0),
unique_modes_check_case_list(Cases0, Var, Cases, InstMaps, !ModeInfo),
instmap_merge(NonLocals, InstMaps, merge_disj, !ModeInfo)
),
GoalExpr = switch(Var, CanFail, Cases),
mode_checkpoint(exit, "switch", !ModeInfo).
:- pred unique_modes_check_goal_call_foreign_proc(
pragma_foreign_proc_attributes::in, pred_id::in, proc_id::in,
list(foreign_arg)::in, list(foreign_arg)::in,
maybe(trace_expr(trace_runtime))::in, pragma_foreign_code_impl::in,
hlds_goal_info::in, hlds_goal_expr::out,
mode_info::in, mode_info::out) is det.
unique_modes_check_goal_call_foreign_proc(Attributes, PredId, ProcId0,
Args, ExtraArgs, MaybeTraceRuntimeCond, PragmaCode,
GoalInfo0, GoalExpr, !ModeInfo) :-
% To modecheck a pragma_c_code, we just modecheck the proc for
% which it is the goal.
mode_checkpoint(enter, "foreign_proc", !ModeInfo),
mode_info_get_call_id(!.ModeInfo, PredId, CallId),
mode_info_set_call_context(call_context_call(plain_call_id(CallId)),
!ModeInfo),
ArgVars = list.map(foreign_arg_var, Args),
unique_modes_check_call(PredId, ProcId0, ArgVars, GoalInfo0, ProcId,
!ModeInfo),
GoalExpr = call_foreign_proc(Attributes, PredId, ProcId, Args, ExtraArgs,
MaybeTraceRuntimeCond, PragmaCode),
mode_info_unset_call_context(!ModeInfo),
mode_checkpoint(exit, "foreign_proc", !ModeInfo).
:- pred unique_modes_check_goal_atomic_goal(atomic_goal_type::in,
atomic_interface_vars::in, atomic_interface_vars::in,
maybe(list(prog_var))::in, hlds_goal::in, list(hlds_goal)::in,
list(atomic_interface_vars)::in,
hlds_goal_info::in, hlds_goal_expr::out,
mode_info::in, mode_info::out) is det.
unique_modes_check_goal_atomic_goal(GoalType, Outer, Inner, MaybeOutputVars,
MainGoal0, OrElseGoals0, OrElseInners, GoalInfo0, GoalExpr,
!ModeInfo) :-
mode_checkpoint(enter, "atomic_goal", !ModeInfo),
(
OrElseGoals0 = [],
unique_modes_check_goal(MainGoal0, MainGoal, !ModeInfo),
OrElseGoals = []
;
OrElseGoals0 = [_ | _],
% The unique mode check on the or_else goals is very similar
% to the unique mode check for disjunctions. Please see
% "unique_modes_check_goal_disj" for disjunctions for discussion
% of this code.
NonLocals = goal_info_get_nonlocals(GoalInfo0),
Determinism = goal_info_get_determinism(GoalInfo0),
( determinism_components(Determinism, _, at_most_many) ->
mode_info_add_live_vars(NonLocals, !ModeInfo),
make_all_nondet_live_vars_mostly_uniq(!ModeInfo),
mode_info_remove_live_vars(NonLocals, !ModeInfo)
;
true
),
Goals0 = [MainGoal0 | OrElseGoals0],
unique_modes_check_disj(Goals0, Determinism, NonLocals, Goals,
InstMapList, !ModeInfo),
(
Goals = [MainGoal | OrElseGoals]
;
Goals = [],
unexpected($module, $pred, "Goals = []")
),
instmap_merge(NonLocals, InstMapList, merge_disj, !ModeInfo)
),
ShortHand = atomic_goal(GoalType, Outer, Inner, MaybeOutputVars,
MainGoal, OrElseGoals, OrElseInners),
GoalExpr = shorthand(ShortHand),
mode_checkpoint(exit, "atomic_goal", !ModeInfo).
%-----------------------------------------------------------------------------%
:- pred unique_modes_check_call(pred_id::in, proc_id::in, list(prog_var)::in,
hlds_goal_info::in, proc_id::out, mode_info::in, mode_info::out) is det.
unique_modes_check_call(PredId, ProcId0, ArgVars, GoalInfo, ProcId,
!ModeInfo) :-
% Set the error list to empty for use below
% (saving the old error list and instmap in variables).
mode_info_get_errors(!.ModeInfo, OldErrors),
mode_info_get_instmap(!.ModeInfo, InstMap0),
mode_info_set_errors([], !ModeInfo),
% First off, try using the existing mode.
mode_info_get_module_info(!.ModeInfo, ModuleInfo),
module_info_pred_proc_info(ModuleInfo, PredId, ProcId0,
PredInfo, ProcInfo),
compute_arg_offset(PredInfo, ArgOffset),
proc_info_get_argmodes(ProcInfo, ProcArgModes0),
proc_info_interface_determinism(ProcInfo, InterfaceDeterminism),
proc_info_never_succeeds(ProcInfo, NeverSucceeds),
unique_modes_check_call_modes(ArgVars, ProcArgModes0, ArgOffset,
InterfaceDeterminism, NeverSucceeds, !ModeInfo),
ModeErrors = ProcInfo ^ mode_errors,
(
ModeErrors = [_ | _],
% mode error in callee for this mode
WaitingVars = set.list_to_set(ArgVars),
mode_info_get_instmap(!.ModeInfo, InstMap),
instmap_lookup_vars(InstMap, ArgVars, ArgInsts),
mode_info_error(WaitingVars,
mode_error_in_callee(ArgVars, ArgInsts, PredId, ProcId0,
ProcInfo ^ mode_errors),
!ModeInfo)
;
ModeErrors = []
),
% See whether or not that worked (and restore the old error list).
mode_info_get_errors(!.ModeInfo, Errors),
mode_info_set_errors(OldErrors, !ModeInfo),
mode_info_get_may_change_called_proc(!.ModeInfo, MayChangeCalledProc),
(
Errors = [],
ProcId = ProcId0
;
Errors = [_ | _],
(
MayChangeCalledProc = may_not_change_called_proc,
% We're not allowed to try a different procedure here, so just
% return all the errors.
ProcId = ProcId0,
list.append(OldErrors, Errors, AllErrors),
mode_info_set_errors(AllErrors, !ModeInfo)
;
MayChangeCalledProc = may_change_called_proc,
% If it didn't work, restore the original instmap, and then call
% modecheck_call_pred. That will try all the modes, and will infer
% new ones if necessary.
%
% We set the declared determinism for newly inferred modes to be
% the same as the determinism inferred for the existing mode
% selected by ordinary (non-unique) mode analysis. This means that
% determinism analysis will report an error if the determinism
% changes as a result of unique mode analysis. That is OK, because
% uniqueness should not affect determinism.
mode_info_set_instmap(InstMap0, !ModeInfo),
proc_info_get_inferred_determinism(ProcInfo, Determinism),
modecheck_call_pred(PredId, yes(Determinism), ProcId0, ProcId,
ArgVars, NewArgVars, GoalInfo, ExtraGoals, !ModeInfo),
(
NewArgVars = ArgVars,
ExtraGoals = no_extra_goals
->
true
;
% This shouldn't happen, since modes.m should do all the
% handling of implied modes.
% XXX It might happen, though, if the user writes strange code;
% we should report a proper error here.
unexpected($module, $pred, "call to implied mode?")
)
)
).
% To check a call, we just look up the required initial insts for the
% arguments of the call, and then check for each argument if the variable
% is nondet-live and the required initial inst was unique.
%
:- pred unique_modes_check_call_modes(list(prog_var)::in, list(mer_mode)::in,
int::in, determinism::in, bool::in, mode_info::in, mode_info::out) is det.
unique_modes_check_call_modes(ArgVars, ProcArgModes, ArgOffset, Determinism,
NeverSucceeds, !ModeInfo) :-
mode_info_get_module_info(!.ModeInfo, ModuleInfo),
mode_list_get_initial_insts(ModuleInfo, ProcArgModes, InitialInsts),
modecheck_var_has_inst_list_no_exact_match(ArgVars, InitialInsts,
ArgOffset, InstVarSub, !ModeInfo),
mode_list_get_final_insts(ModuleInfo, ProcArgModes, FinalInsts0),
inst_list_apply_substitution(InstVarSub, FinalInsts0, FinalInsts),
modecheck_set_var_inst_list(ArgVars, InitialInsts, FinalInsts,
ArgOffset, NewArgVars, ExtraGoals, !ModeInfo),
(
NewArgVars = ArgVars,
ExtraGoals = no_extra_goals
->
true
;
% This shouldn't happen, since modes.m should do all the handling
% of implied modes.
unexpected($module, $pred, "call to implied mode?")
),
(
NeverSucceeds = yes,
instmap.init_unreachable(InstMap),
mode_info_set_instmap(InstMap, !ModeInfo)
;
NeverSucceeds = no,
% Check whether we are at a call to a nondet predicate.
% If so, mark all the currently nondet-live variables
% whose inst is `unique' as instead being only `mostly_unique'.
( determinism_components(Determinism, _, at_most_many) ->
make_all_nondet_live_vars_mostly_uniq(!ModeInfo)
;
true
)
).
%-----------------------------------------------------------------------------%
:- pred unique_modes_check_conj(conj_type::in,
list(hlds_goal)::in, list(hlds_goal)::out, mode_info::in, mode_info::out)
is det.
% Just process each conjunct in turn. Note that we don't do any
% reordering of conjuncts here, although we do flatten conjunctions.
%
unique_modes_check_conj(_ConjType, [], [], !ModeInfo).
unique_modes_check_conj(ConjType, [Goal0 | Goals0], Goals, !ModeInfo) :-
( Goal0 = hlds_goal(conj(ConjType, ConjGoals), _) ->
list.append(ConjGoals, Goals0, Goals1),
unique_modes_check_conj(ConjType, Goals1, Goals, !ModeInfo)
;
unique_modes_check_conj_2(ConjType, Goal0, Goals0, Goals, !ModeInfo)
).
:- pred unique_modes_check_conj_2(conj_type::in,
hlds_goal::in, list(hlds_goal)::in, list(hlds_goal)::out,
mode_info::in, mode_info::out) is det.
unique_modes_check_conj_2(ConjType, Goal0, Goals0, [Goal | Goals],
!ModeInfo) :-
NonLocals = goal_get_nonlocals(Goal0),
mode_info_remove_live_vars(NonLocals, !ModeInfo),
unique_modes_check_goal(Goal0, Goal, !ModeInfo),
mode_info_get_instmap(!.ModeInfo, InstMap),
( instmap_is_unreachable(InstMap) ->
% We should not mode-analyse the remaining goals, since they are
% unreachable. Instead we optimize them away, so that later passes
% won't complain about them not having unique mode information.
mode_info_remove_goals_live_vars(Goals0, !ModeInfo),
Goals = []
;
unique_modes_check_conj(ConjType, Goals0, Goals, !ModeInfo)
).
%-----------------------------------------------------------------------------%
% Make_par_conj_nonlocal_multiset builds a multiset (bag) of all
% the nonlocals of the conjuncts.
%
:- pred make_par_conj_nonlocal_multiset(list(hlds_goal)::in,
bag(prog_var)::out) is det.
make_par_conj_nonlocal_multiset([], Empty) :-
bag.init(Empty).
make_par_conj_nonlocal_multiset([Goal | Goals], NonLocalsMultiSet) :-
make_par_conj_nonlocal_multiset(Goals, NonLocalsMultiSet0),
NonLocals = goal_get_nonlocals(Goal),
set.to_sorted_list(NonLocals, NonLocalsList),
bag.from_list(NonLocalsList, NonLocalsMultiSet1),
bag.union(NonLocalsMultiSet0, NonLocalsMultiSet1, NonLocalsMultiSet).
% To unique-modecheck a parallel conjunction, we find the variables
% that are nonlocal to more than one conjunct and make them shared,
% then we unique-modecheck the conjuncts.
%
% The variables that occur in more than one conjunct must be shared
% because otherwise it would be possible to make them become clobbered
% which would introduce an implicit dependency between the conjuncts
% which we do not allow.
%
:- pred unique_modes_check_par_conj(list(hlds_goal)::in, bag(prog_var)::in,
list(hlds_goal)::out, list(pair(instmap, set(prog_var)))::out,
mode_info::in, mode_info::out) is det.
unique_modes_check_par_conj(Goals0, NonLocalVarsBag, Goals, Instmaps,
!ModeInfo) :-
unique_modes_check_par_conj_0(NonLocalVarsBag, !ModeInfo),
unique_modes_check_par_conj_1(Goals0, Goals, Instmaps, !ModeInfo).
% Figure out which variables occur in more than one conjunct and make them
% shared.
%
:- pred unique_modes_check_par_conj_0(bag(prog_var)::in,
mode_info::in, mode_info::out) is det.
unique_modes_check_par_conj_0(NonLocalVarsBag, !ModeInfo) :-
bag.to_assoc_list(NonLocalVarsBag, NonLocalVarsList),
list.filter_map((pred(Pair::in, Var::out) is semidet :-
Pair = Var - Multiplicity,
Multiplicity > 1
), NonLocalVarsList, SharedList),
mode_info_get_instmap(!.ModeInfo, InstMap0),
instmap_lookup_vars(InstMap0, SharedList, VarInsts),
mode_info_get_module_info(!.ModeInfo, ModuleInfo0),
make_shared_inst_list(VarInsts, SharedVarInsts,
ModuleInfo0, ModuleInfo1),
mode_info_set_module_info(ModuleInfo1, !ModeInfo),
instmap_set_vars_corresponding(SharedList, SharedVarInsts,
InstMap0, InstMap1),
mode_info_set_instmap(InstMap1, !ModeInfo).
% Just process each conjunct in turn. Because we have already done
% modechecking, we know that there are no attempts to bind a variable in
% multiple parallel conjuncts, so we don't need to lock/unlock variables.
%
:- pred unique_modes_check_par_conj_1(list(hlds_goal)::in,
list(hlds_goal)::out, list(pair(instmap, set(prog_var)))::out,
mode_info::in, mode_info::out) is det.
unique_modes_check_par_conj_1([], [], [], !ModeInfo).
unique_modes_check_par_conj_1([Goal0 | Goals0], [Goal | Goals],
[InstMap - NonLocals | InstMaps], !ModeInfo) :-
NonLocals = goal_get_nonlocals(Goal0),
mode_info_get_instmap(!.ModeInfo, InstMap0),
unique_modes_check_goal(Goal0, Goal, !ModeInfo),
mode_info_get_instmap(!.ModeInfo, InstMap),
mode_info_set_instmap(InstMap0, !ModeInfo),
unique_modes_check_par_conj_1(Goals0, Goals, InstMaps, !ModeInfo).
%-----------------------------------------------------------------------------%
% Process each of the disjunctions in turn, making sure to restore the
% original instmap before processing the next one. Collect up a list
% of the resulting instmaps.
%
:- pred unique_modes_check_disj(list(hlds_goal)::in, determinism::in,
set(prog_var)::in, list(hlds_goal)::out, list(instmap)::out,
mode_info::in, mode_info::out) is det.
unique_modes_check_disj([], _, _, [], [], !ModeInfo).
unique_modes_check_disj([Goal0 | Goals0], DisjDetism, DisjNonLocals,
[Goal | Goals], [InstMap | InstMaps], !ModeInfo) :-
mode_info_get_instmap(!.ModeInfo, InstMap0),
% If you modify this code, you may also need to modify
% unique_modecheck_clause_disj or the code that calls it.
prepare_for_disjunct(Goal0, DisjDetism, DisjNonLocals, !ModeInfo),
unique_modes_check_goal(Goal0, Goal, !ModeInfo),
mode_info_get_instmap(!.ModeInfo, InstMap),
mode_info_set_instmap(InstMap0, !ModeInfo),
unique_modes_check_disj(Goals0, DisjDetism, DisjNonLocals, Goals, InstMaps,
!ModeInfo).
prepare_for_disjunct(Goal0, DisjDetism, DisjNonLocals, !ModeInfo) :-
(
% If the disjunction was model_nondet, then we already marked all the
% non-locals as only being mostly-unique, so we don't need to do
% anything special here...
\+ determinism_components(DisjDetism, _, at_most_many),
% ... but for model_semi or model_det disjunctions, if the _disjunct_
% can fail, then we still might backtrack to another disjunct, so again
% in that case we need to mark all the non-locals as being only
% mostly-unique rather than unique.
Goal0 = hlds_goal(_, GoalInfo0),
Determinism = goal_info_get_determinism(GoalInfo0),
determinism_components(Determinism, CanFail, _),
CanFail = can_fail
->
mode_info_add_live_vars(DisjNonLocals, !ModeInfo),
make_all_nondet_live_vars_mostly_uniq(!ModeInfo),
mode_info_remove_live_vars(DisjNonLocals, !ModeInfo)
;
true
).
%-----------------------------------------------------------------------------%
:- pred unique_modes_check_case_list(list(case)::in, prog_var::in,
list(case)::out, list(instmap)::out, mode_info::in, mode_info::out) is det.
unique_modes_check_case_list([], _Var, [], [], !ModeInfo).
unique_modes_check_case_list([Case0 | Cases0], Var, [Case | Cases],
[InstMap | InstMaps], !ModeInfo) :-
Case0 = case(MainConsId, OtherConsIds, Goal0),
mode_info_get_instmap(!.ModeInfo, InstMap0),
% If you modify this code, you may also need to modify
% unique_modecheck_clause_switch or the code that calls it.
% Update the instmap to reflect the binding of Var to MainConsId or
% one of the OtherConsIds before processing this case.
modecheck_functors_test(Var, MainConsId, OtherConsIds, !ModeInfo),
mode_info_get_instmap(!.ModeInfo, InstMap1),
( instmap_is_reachable(InstMap1) ->
unique_modes_check_goal(Goal0, Goal1, !ModeInfo)
;
% We should not mode-analyse the goal, since it is unreachable.
% Instead we optimize the goal away, so that later passes
% won't complain about it not having unique mode information.
Goal1 = true_goal
),
mode_info_get_instmap(!.ModeInfo, InstMap),
fixup_instmap_switch_var(Var, InstMap0, InstMap, Goal1, Goal),
Case = case(MainConsId, OtherConsIds, Goal),
mode_info_set_instmap(InstMap0, !ModeInfo),
unique_modes_check_case_list(Cases0, Var, Cases, InstMaps, !ModeInfo).
%-----------------------------------------------------------------------------%
:- end_module check_hlds.unique_modes.
%-----------------------------------------------------------------------------%
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