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3c60c0e485
Estimated hours taken: 4 Branches: main compiler/*.m: Change a bunch of modules to import only one module per line, even from the library. compiler/mlds_to_il.m: compiler/mlds_to_managed.m: Convert these modules to our current coding style. Use state variables where appropriate. Use predmode declarations where possible.
270 lines
9.9 KiB
Mathematica
270 lines
9.9 KiB
Mathematica
%-----------------------------------------------------------------------------%
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% Copyright (C) 2002-2005 The University of Melbourne.
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% This file may only be copied under the terms of the GNU General
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% Public License - see the file COPYING in the Mercury distribution.
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%-----------------------------------------------------------------------------%
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%
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% File stack_alloc.m
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%
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% Authors: zs, conway.
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%
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% This module allocates stack slots to the variables that need to be saved
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% across a call, across a goal that may fail, or in a parallel conjunction.
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%
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% The jobs is done in two steps. First we traverse the predicate definition
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% looking for sets of variables that must be saved on the stack at the same
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% time. If --optimize-stack-slots is set, then this phase is done by
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% stack_opt.m; if --optimize-stack-slots is not set, then it is done by
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% this module. Then we use a graph colouring algorithm to find an allocation
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% of stack slots (colours) to variables such that in each set of variables
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% that must be saved at the same time, each variable has a different colour.
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%-----------------------------------------------------------------------------%
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:- module ll_backend__stack_alloc.
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:- interface.
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:- import_module hlds__hlds_module.
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:- import_module hlds__hlds_pred.
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:- import_module io.
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:- pred allocate_stack_slots_in_proc(pred_id::in, proc_id::in, module_info::in,
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proc_info::in, proc_info::out, io::di, io::uo) is det.
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%-----------------------------------------------------------------------------%
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%-----------------------------------------------------------------------------%
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:- implementation.
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:- import_module check_hlds__goal_path.
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:- import_module check_hlds__type_util.
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:- import_module hlds__code_model.
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:- import_module hlds__hlds_data.
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:- import_module hlds__hlds_goal.
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:- import_module hlds__hlds_llds.
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:- import_module libs__globals.
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:- import_module libs__graph_colour.
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:- import_module libs__options.
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:- import_module libs__trace_params.
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:- import_module ll_backend__live_vars.
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:- import_module ll_backend__liveness.
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:- import_module ll_backend__llds.
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:- import_module ll_backend__stack_opt.
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:- import_module ll_backend__trace.
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:- import_module parse_tree__prog_data.
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:- import_module assoc_list.
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:- import_module bool.
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:- import_module int.
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:- import_module list.
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:- import_module map.
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:- import_module require.
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:- import_module set.
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:- import_module std_util.
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%-----------------------------------------------------------------------------%
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allocate_stack_slots_in_proc(PredId, _ProcId, ModuleInfo, !ProcInfo, !IO) :-
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initial_liveness(!.ProcInfo, PredId, ModuleInfo, Liveness0),
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module_info_pred_info(ModuleInfo, PredId, PredInfo),
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module_info_globals(ModuleInfo, Globals),
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globals__get_trace_level(Globals, TraceLevel),
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(
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eff_trace_level_needs_input_vars(PredInfo, !.ProcInfo,
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TraceLevel) = yes
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->
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trace__fail_vars(ModuleInfo, !.ProcInfo, FailVars)
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;
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set__init(FailVars)
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),
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body_should_use_typeinfo_liveness(PredInfo, Globals, TypeInfoLiveness),
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globals__lookup_bool_option(Globals, opt_no_return_calls,
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OptNoReturnCalls),
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AllocData = alloc_data(ModuleInfo, !.ProcInfo, TypeInfoLiveness,
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OptNoReturnCalls),
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set__init(NondetLiveness0),
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SimpleStackAlloc0 = stack_alloc(set__make_singleton_set(FailVars)),
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proc_info_goal(!.ProcInfo, Goal0),
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build_live_sets_in_goal(Goal0, Goal, FailVars, AllocData,
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SimpleStackAlloc0, SimpleStackAlloc, Liveness0, _Liveness,
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NondetLiveness0, _NondetLiveness),
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proc_info_set_goal(Goal, !ProcInfo),
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SimpleStackAlloc = stack_alloc(LiveSets0),
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trace__do_we_need_maxfr_slot(Globals, PredInfo, !ProcInfo),
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trace__reserved_slots(ModuleInfo, PredInfo, !.ProcInfo, Globals,
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NumReservedSlots, MaybeReservedVarInfo),
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(
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MaybeReservedVarInfo = yes(ResVar - _),
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set__singleton_set(ResVarSet, ResVar),
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set__insert(LiveSets0, ResVarSet, LiveSets1)
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;
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MaybeReservedVarInfo = no,
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LiveSets1 = LiveSets0
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),
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proc_info_vartypes(!.ProcInfo, VarTypes),
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filter_out_dummy_values(VarTypes, LiveSets1, LiveSets, DummyVars),
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graph_colour__group_elements(LiveSets, ColourSets),
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set__to_sorted_list(ColourSets, ColourList),
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proc_info_interface_code_model(!.ProcInfo, CodeModel),
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allocate_stack_slots(ColourList, CodeModel, NumReservedSlots,
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MaybeReservedVarInfo, StackSlots1),
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allocate_dummy_stack_slots(DummyVars, CodeModel, -1,
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StackSlots1, StackSlots),
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proc_info_set_stack_slots(StackSlots, !ProcInfo).
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:- pred filter_out_dummy_values(vartypes::in,
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set(set(prog_var))::in, set(set(prog_var))::out,
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list(prog_var)::out) is det.
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filter_out_dummy_values(VarTypes, LiveSet0, LiveSet, DummyVars) :-
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set__to_sorted_list(LiveSet0, LiveList0),
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filter_out_dummy_values_2(VarTypes, LiveList0, LiveList,
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set__init, Dummies),
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set__list_to_set(LiveList, LiveSet),
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set__to_sorted_list(Dummies, DummyVars).
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:- pred filter_out_dummy_values_2(vartypes::in,
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list(set(prog_var))::in, list(set(prog_var))::out,
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set(prog_var)::in, set(prog_var)::out) is det.
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filter_out_dummy_values_2(_VarTypes, [], [], !Dummies).
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filter_out_dummy_values_2(VarTypes, [LiveSet0 | LiveSets0], LiveSets,
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!Dummies) :-
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filter_out_dummy_values_2(VarTypes, LiveSets0, LiveSets1, !Dummies),
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set__to_sorted_list(LiveSet0, LiveList0),
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list__filter(var_is_of_dummy_type(VarTypes), LiveList0,
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DummyVars, NonDummyVars),
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set__insert_list(!.Dummies, DummyVars, !:Dummies),
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(
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NonDummyVars = [],
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LiveSets = LiveSets1
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;
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NonDummyVars = [_ | _],
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LiveSets = [list_to_set(NonDummyVars) | LiveSets1]
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).
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%-----------------------------------------------------------------------------%
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%-----------------------------------------------------------------------------%
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:- type stack_alloc
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---> stack_alloc(
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set(set(prog_var)) % The sets of vars that need to
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% be on the stack at the same
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% time.
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).
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:- instance stack_alloc_info(stack_alloc) where [
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pred(at_call_site/4) is alloc_at_call_site,
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pred(at_resume_site/4) is alloc_at_resume_site,
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pred(at_par_conj/4) is alloc_at_par_conj
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].
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:- pred alloc_at_call_site(need_across_call::in, hlds_goal_info::in,
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stack_alloc::in, stack_alloc::out) is det.
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alloc_at_call_site(NeedAtCall, _GoalInfo, StackAlloc0, StackAlloc) :-
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NeedAtCall = need_across_call(ForwardVars, ResumeVars, NondetLiveVars),
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LiveSet = set__union_list([ForwardVars, ResumeVars, NondetLiveVars]),
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StackAlloc0 = stack_alloc(LiveSets0),
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LiveSets = set__insert(LiveSets0, LiveSet),
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StackAlloc = stack_alloc(LiveSets).
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:- pred alloc_at_resume_site(need_in_resume::in, hlds_goal_info::in,
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stack_alloc::in, stack_alloc::out) is det.
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alloc_at_resume_site(NeedAtResume, _GoalInfo, StackAlloc0, StackAlloc) :-
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NeedAtResume = need_in_resume(ResumeOnStack, ResumeVars,
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NondetLiveVars),
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(
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ResumeOnStack = no,
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StackAlloc = StackAlloc0
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;
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ResumeOnStack = yes,
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LiveSet = set__union(ResumeVars, NondetLiveVars),
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StackAlloc0 = stack_alloc(LiveSets0),
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LiveSets = set__insert(LiveSets0, LiveSet),
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StackAlloc = stack_alloc(LiveSets)
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).
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:- pred alloc_at_par_conj(need_in_par_conj::in, hlds_goal_info::in,
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stack_alloc::in, stack_alloc::out) is det.
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alloc_at_par_conj(NeedParConj, _GoalInfo, StackAlloc0, StackAlloc) :-
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NeedParConj = need_in_par_conj(StackVars),
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StackAlloc0 = stack_alloc(LiveSets0),
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LiveSets = set__insert(LiveSets0, StackVars),
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StackAlloc = stack_alloc(LiveSets).
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%-----------------------------------------------------------------------------%
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%-----------------------------------------------------------------------------%
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:- pred allocate_stack_slots(list(set(prog_var))::in, code_model::in, int::in,
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maybe(pair(prog_var, int))::in, stack_slots::out) is det.
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allocate_stack_slots(ColourList, CodeModel, NumReservedSlots,
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MaybeReservedVarInfo, StackSlots) :-
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% The reserved slots are referred to by fixed number
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% (e.g. framevar(1)) in trace__setup.
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FirstVarSlot = NumReservedSlots + 1,
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allocate_stack_slots_2(ColourList, CodeModel, FirstVarSlot,
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MaybeReservedVarInfo, map__init, StackSlots).
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:- pred allocate_stack_slots_2(list(set(prog_var))::in, code_model::in,
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int::in, maybe(pair(prog_var, int))::in,
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stack_slots::in, stack_slots::out) is det.
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allocate_stack_slots_2([], _, _, _, !StackSlots).
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allocate_stack_slots_2([Vars | VarSets], CodeModel, N0, MaybeReservedVarInfo,
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!StackSlots) :-
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(
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MaybeReservedVarInfo = yes(ResVar - ResSlotNum),
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set__member(ResVar, Vars)
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->
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SlotNum = ResSlotNum,
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N1 = N0
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;
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SlotNum = N0,
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N1 = N0 + 1
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),
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set__to_sorted_list(Vars, VarList),
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allocate_same_stack_slot(VarList, CodeModel, SlotNum, !StackSlots),
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allocate_stack_slots_2(VarSets, CodeModel, N1, MaybeReservedVarInfo,
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!StackSlots).
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:- pred allocate_same_stack_slot(list(prog_var)::in, code_model::in, int::in,
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stack_slots::in, stack_slots::out) is det.
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allocate_same_stack_slot([], _CodeModel, _Slot, !StackSlots).
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allocate_same_stack_slot([Var | Vars], CodeModel, Slot, !StackSlots) :-
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( CodeModel = model_non ->
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Locn = nondet_slot(Slot)
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;
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Locn = det_slot(Slot)
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),
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map__det_insert(!.StackSlots, Var, Locn, !:StackSlots),
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allocate_same_stack_slot(Vars, CodeModel, Slot, !StackSlots).
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% We must not allocate the same stack slot to dummy variables. If we do,
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% then the code that saves variables on the stack at calls will get confused.
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% After saving one dummy variable on the stack, it will try to save the next
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% in the same stack slot; believing the first variable to still be live, it
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% will move it away.
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%
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% In ordinary grades, it is possible to have one value of type io__state
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% and another of type store__store live at the same time; in debugging grades,
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% due to our policy of extending variable lifetimes, more than one io__state
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% may be live at the same time.
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:- pred allocate_dummy_stack_slots(list(prog_var)::in, code_model::in,
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int::in, stack_slots::in, stack_slots::out) is det.
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allocate_dummy_stack_slots([], _, _, !StackSlots).
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allocate_dummy_stack_slots([Var | Vars], CodeModel, N0, !StackSlots) :-
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allocate_same_stack_slot([Var], CodeModel, N0, !StackSlots),
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allocate_dummy_stack_slots(Vars, CodeModel, N0 - 1, !StackSlots).
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%-----------------------------------------------------------------------------%
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