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mercury/compiler/dupproc.m
2022-07-07 06:24:09 +10:00

446 lines
16 KiB
Mathematica

%-----------------------------------------------------------------------------%
% vim: ft=mercury ts=4 sw=4 et
%-----------------------------------------------------------------------------%
% Copyright (C) 2005-2007, 2009-2011 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: dupproc.m.
% Author: zs.
%
% The job of this module is to eliminate duplicate procedure bodies. These
% can arise when a predicate has several modes that differ only in details that
% don't matter for code generation, such as in/out vs di/uo, or (in some cases)
% in/out, vs any/any.
%
%-----------------------------------------------------------------------------%
:- module ll_backend.dupproc.
:- interface.
:- import_module ll_backend.llds.
:- import_module mdbcomp.
:- import_module mdbcomp.prim_data.
:- import_module assoc_list.
:- import_module list.
:- import_module map.
%-----------------------------------------------------------------------------%
:- pred eliminate_duplicate_procs(assoc_list(proc_label, c_procedure)::in,
list(c_procedure)::out,
map(proc_label, proc_label)::in, map(proc_label, proc_label)::out) is det.
%-----------------------------------------------------------------------------%
%-----------------------------------------------------------------------------%
:- implementation.
:- import_module ll_backend.opt_util.
:- import_module int.
:- import_module maybe.
:- import_module pair.
:- import_module require.
%-----------------------------------------------------------------------------%
eliminate_duplicate_procs(IdProcs, Procs, !DupProcMap) :-
(
IdProcs = [],
Procs = []
;
IdProcs = [_Id - Proc],
Procs = [Proc]
;
IdProcs = [Id1 - Proc1 | IdProcsTail],
IdProcsTail = [_ | _],
apply_dup_proc_map_in_proc(Proc1, StdProc1, !.DupProcMap),
eliminate_dup_procs([Id1 - StdProc1], IdProcsTail, FinalIdProcsTail,
!DupProcMap),
assoc_list.values(FinalIdProcsTail, FinalProcsTail),
Procs = [Proc1 | FinalProcsTail]
).
:- pred eliminate_dup_procs(assoc_list(proc_label, c_procedure)::in,
assoc_list(proc_label, c_procedure)::in,
assoc_list(proc_label, c_procedure)::out,
map(proc_label, proc_label)::in, map(proc_label, proc_label)::out) is det.
eliminate_dup_procs(_ModelStdProcs, [], [], !DupProcMap).
eliminate_dup_procs(ModelStdProcs0, [Id - Proc0 | IdProcs0],
[Id - Proc | IdProcs], !DupProcMap) :-
( if
Proc0 ^ cproc_may_alter_rtti = may_alter_rtti,
find_matching_model_proc(ModelStdProcs0, Id, Proc0, !.DupProcMap,
MatchingId),
maybe_redirect_proc(Proc0, MatchingId, MaybeProc),
MaybeProc = yes(ProcPrime)
then
Proc = ProcPrime,
map.det_insert(Id, MatchingId, !DupProcMap),
ModelStdProcs = ModelStdProcs0
else
Proc = Proc0,
apply_dup_proc_map_in_proc(Proc0, StdProc0, !.DupProcMap),
% Since the number of procedures per predicate is tiny,
% the quadratic behavior here is not a problem.
list.append(ModelStdProcs0, [Id - StdProc0], ModelStdProcs)
),
eliminate_dup_procs(ModelStdProcs, IdProcs0, IdProcs, !DupProcMap).
:- pred find_matching_model_proc(assoc_list(proc_label, c_procedure)::in,
proc_label::in, c_procedure::in, map(proc_label, proc_label)::in,
proc_label::out) is semidet.
find_matching_model_proc([ModelId - ModelStdProc | ModelIdProcs], Id, Proc,
DupProcMap, MatchingId) :-
map.det_insert(Id, ModelId, DupProcMap, AugDupProcMap),
apply_dup_proc_map_in_proc(Proc, StdProc, AugDupProcMap),
StdInstrs = StdProc ^ cproc_code,
ModelStdInstrs = ModelStdProc ^ cproc_code,
( if StdInstrs = ModelStdInstrs then
MatchingId = ModelId
else
find_matching_model_proc(ModelIdProcs, Id, Proc, DupProcMap,
MatchingId)
).
% If the body of the matching procedures is significant enough,
% redirect the current procedure body to jump to the start of the
% model procedure's body instead. On the other hand, if the body
% is just a few instructions with no jumps, then this redirection
% jump would be a greater time cost than the space cost of duplicating
% the procedure body, so in that case we avoid the transformation
% by not returning the new body.
%
:- pred maybe_redirect_proc(c_procedure::in, proc_label::in,
maybe(c_procedure)::out) is det.
maybe_redirect_proc(Proc0, TargetProcLabel, MaybeProc) :-
Instrs0 = Proc0 ^ cproc_code,
get_prologue(Instrs0, LabelInstr, _Comments, LaterInstrs),
TargetLabel = entry_label(entry_label_local, TargetProcLabel),
Redirect = llds_instr(goto(code_label(TargetLabel)),
"Redirect to procedure with identical body"),
list.filter(disallowed_instr, LaterInstrs, DisallowedInstrs),
list.length(LaterInstrs, NumLaterInstrs),
( if
DisallowedInstrs = [],
% The threshold here is a guess. I don't think the precise value
% has much effect, so I don't think it is worth making it configurable.
NumLaterInstrs < 6
then
MaybeProc = no
else
Instrs = [LabelInstr, Redirect],
Proc = Proc0 ^ cproc_code := Instrs,
MaybeProc = yes(Proc)
).
:- pred disallowed_instr(instruction::in) is semidet.
disallowed_instr(llds_instr(Instr, _)) :-
(
Instr = if_val(_, _)
;
Instr = llcall(_, _, _, _, _, _)
).
%-----------------------------------------------------------------------------%
:- pred apply_dup_proc_map_in_proc(c_procedure::in, c_procedure::out,
map(proc_label, proc_label)::in) is det.
apply_dup_proc_map_in_proc(CProc, StdCProc, DupProcMap) :-
Instrs = CProc ^ cproc_code,
apply_dup_proc_map_in_instrs(Instrs, StdInstrs, DupProcMap),
StdCProc = CProc ^ cproc_code := StdInstrs.
:- pred apply_dup_proc_map_in_instrs(
list(instruction)::in, list(instruction)::out,
map(proc_label, proc_label)::in) is det.
apply_dup_proc_map_in_instrs([], [], _).
apply_dup_proc_map_in_instrs([llds_instr(Instr, _) | Instrs],
[llds_instr(StdInstr, "") | StdInstrs], DupProcMap) :-
apply_dup_proc_map_in_instr(Instr, StdInstr, DupProcMap),
apply_dup_proc_map_in_instrs(Instrs, StdInstrs, DupProcMap).
:- pred apply_dup_proc_map_in_instr(instr::in, instr::out,
map(proc_label, proc_label)::in) is det.
apply_dup_proc_map_in_instr(Instr, StdInstr, DupProcMap) :-
(
Instr = block(NumIntTemps, NumFloatTemps, Instrs),
apply_dup_proc_map_in_instrs(Instrs, StdInstrs, DupProcMap),
StdInstr = block(NumIntTemps, NumFloatTemps, StdInstrs)
;
Instr = assign(Lval, Rval),
apply_dup_proc_map_in_rval(Rval, StdRval, DupProcMap),
StdInstr = assign(Lval, StdRval)
;
Instr = keep_assign(Lval, Rval),
apply_dup_proc_map_in_rval(Rval, StdRval, DupProcMap),
StdInstr = keep_assign(Lval, StdRval)
;
Instr = llcall(Target, Cont, LiveInfo, Context, GoalPath, Model),
apply_dup_proc_map_in_code_addr(Target, StdTarget, DupProcMap),
apply_dup_proc_map_in_code_addr(Cont, StdCont, DupProcMap),
StdInstr = llcall(StdTarget, StdCont, LiveInfo, Context, GoalPath,
Model)
;
Instr = mkframe(FrameInfo, MaybeCodeAddr),
(
FrameInfo = temp_frame(_),
StdFrameInfo = FrameInfo
;
FrameInfo = ordinary_frame(_, NumSlots),
StdFrameInfo = ordinary_frame("", NumSlots)
),
apply_dup_proc_map_in_maybe_code_addr(MaybeCodeAddr, MaybeStdCodeAddr,
DupProcMap),
StdInstr = mkframe(StdFrameInfo, MaybeStdCodeAddr)
;
Instr = label(Label),
apply_dup_proc_map_in_label(Label, StdLabel, DupProcMap),
StdInstr = label(StdLabel)
;
Instr = goto(Target),
apply_dup_proc_map_in_code_addr(Target, StdTarget, DupProcMap),
StdInstr = goto(StdTarget)
;
Instr = computed_goto(Rval, Targets),
apply_dup_proc_map_in_maybe_labels(Targets, StdTargets, DupProcMap),
StdInstr = computed_goto(Rval, StdTargets)
;
Instr = if_val(Rval, Target),
apply_dup_proc_map_in_rval(Rval, StdRval, DupProcMap),
apply_dup_proc_map_in_code_addr(Target, StdTarget, DupProcMap),
StdInstr = if_val(StdRval, StdTarget)
;
Instr = incr_sp(NumSlots, _, Kind),
StdInstr = incr_sp(NumSlots, "", Kind)
;
Instr = fork_new_child(Lval, Child),
apply_dup_proc_map_in_label(Child, StdChild, DupProcMap),
StdInstr = fork_new_child(Lval, StdChild)
;
Instr = join_and_continue(Lval, Label),
apply_dup_proc_map_in_label(Label, StdLabel, DupProcMap),
StdInstr = join_and_continue(Lval, StdLabel)
;
% The labels occurring in foreign_proc_code instructions
% cannot be substituted.
Instr = foreign_proc_code(_, _, _, _, _, _, _, _, _, _),
StdInstr = Instr
;
Instr = lc_wait_free_slot(Rval, Lval, Label),
apply_dup_proc_map_in_rval(Rval, StdRval, DupProcMap),
apply_dup_proc_map_in_label(Label, StdLabel, DupProcMap),
StdInstr = lc_wait_free_slot(StdRval, Lval, StdLabel)
;
Instr = lc_spawn_off(LCRval, LCSRval, Label),
apply_dup_proc_map_in_rval(LCRval, StdLCRval, DupProcMap),
apply_dup_proc_map_in_rval(LCSRval, StdLCSRval, DupProcMap),
apply_dup_proc_map_in_label(Label, StdLabel, DupProcMap),
StdInstr = lc_spawn_off(StdLCRval, StdLCSRval, StdLabel)
;
Instr = lc_join_and_terminate(LCRval, LCSRval),
apply_dup_proc_map_in_rval(LCRval, StdLCRval, DupProcMap),
apply_dup_proc_map_in_rval(LCSRval, StdLCSRval, DupProcMap),
StdInstr = lc_join_and_terminate(StdLCRval, StdLCSRval)
;
% These instructions have no labels inside them, or anything else
% that can be standardized.
( Instr = comment(_)
; Instr = livevals(_)
; Instr = arbitrary_c_code(_, _, _)
; Instr = save_maxfr(_)
; Instr = restore_maxfr(_)
; Instr = incr_hp(_, _, _, _, _, _, _, _)
; Instr = mark_hp(_)
; Instr = restore_hp(_)
; Instr = free_heap(_)
; Instr = push_region_frame(_, _)
; Instr = region_fill_frame(_, _, _, _, _)
; Instr = region_set_fixed_slot(_, _, _)
; Instr = use_and_maybe_pop_region_frame(_, _)
; Instr = store_ticket(_)
; Instr = reset_ticket(_, _)
; Instr = discard_ticket
; Instr = prune_ticket
; Instr = mark_ticket_stack(_)
; Instr = prune_tickets_to(_)
; Instr = decr_sp(_)
; Instr = decr_sp_and_return(_)
; Instr = init_sync_term(_, _, _)
; Instr = lc_create_loop_control(_, _)
),
StdInstr = Instr
).
% Compute the standard form of a proc_label.
%
:- pred apply_dup_proc_map_in_proc_label(proc_label::in, proc_label::out,
map(proc_label, proc_label)::in) is det.
apply_dup_proc_map_in_proc_label(ProcLabel, StdProcLabel, DupProcMap) :-
( if map.search(DupProcMap, ProcLabel, FoundProcLabel) then
StdProcLabel = FoundProcLabel
else
StdProcLabel = ProcLabel
).
% Compute the standard form of a label.
%
:- pred apply_dup_proc_map_in_label(label::in, label::out,
map(proc_label, proc_label)::in) is det.
apply_dup_proc_map_in_label(Label, StdLabel, DupProcMap) :-
(
Label = internal_label(Num, ProcLabel),
apply_dup_proc_map_in_proc_label(ProcLabel, StdProcLabel, DupProcMap),
StdLabel = internal_label(Num, StdProcLabel)
;
Label = entry_label(Type, ProcLabel),
apply_dup_proc_map_in_proc_label(ProcLabel, StdProcLabel, DupProcMap),
StdLabel = entry_label(Type, StdProcLabel)
).
% Compute the standard form of a list(label).
%
:- pred apply_dup_proc_map_in_maybe_labels(list(maybe(label))::in,
list(maybe(label))::out, map(proc_label, proc_label)::in) is det.
apply_dup_proc_map_in_maybe_labels([], [], _DupProcMap).
apply_dup_proc_map_in_maybe_labels([MaybeLabel | MaybeLabels],
[StdMaybeLabel | StdMaybeLabels], DupProcMap) :-
(
MaybeLabel = yes(Label),
apply_dup_proc_map_in_label(Label, StdLabel, DupProcMap),
StdMaybeLabel = yes(StdLabel)
;
MaybeLabel = no,
StdMaybeLabel = no
),
apply_dup_proc_map_in_maybe_labels(MaybeLabels, StdMaybeLabels,
DupProcMap).
% Compute the standard form of a code_addr.
%
:- pred apply_dup_proc_map_in_code_addr(code_addr::in, code_addr::out,
map(proc_label, proc_label)::in) is det.
apply_dup_proc_map_in_code_addr(CodeAddr, StdCodeAddr, DupProcMap) :-
(
CodeAddr = code_label(Label),
apply_dup_proc_map_in_label(Label, StdLabel, DupProcMap),
StdCodeAddr = code_label(StdLabel)
;
CodeAddr = code_imported_proc(ProcLabel),
apply_dup_proc_map_in_proc_label(ProcLabel, StdProcLabel, DupProcMap),
StdCodeAddr = code_imported_proc(StdProcLabel)
;
( CodeAddr = code_succip
; CodeAddr = do_succeed(_)
; CodeAddr = do_redo
; CodeAddr = do_fail
; CodeAddr = do_trace_redo_fail_shallow
; CodeAddr = do_trace_redo_fail_deep
; CodeAddr = do_call_closure(_)
; CodeAddr = do_call_class_method(_)
; CodeAddr = do_not_reached
),
StdCodeAddr = CodeAddr
).
% Compute the standard form of a maybe(code_addr).
%
:- pred apply_dup_proc_map_in_maybe_code_addr(maybe(code_addr)::in,
maybe(code_addr)::out, map(proc_label, proc_label)::in) is det.
apply_dup_proc_map_in_maybe_code_addr(MaybeCodeAddr, MaybeStdCodeAddr,
DupProcMap) :-
(
MaybeCodeAddr = no,
MaybeStdCodeAddr = no
;
MaybeCodeAddr = yes(CodeAddr),
apply_dup_proc_map_in_code_addr(CodeAddr, StdCodeAddr, DupProcMap),
MaybeStdCodeAddr = yes(StdCodeAddr)
).
% Compute the standard form of an rval.
%
:- pred apply_dup_proc_map_in_rval(rval::in, rval::out,
map(proc_label, proc_label)::in) is det.
apply_dup_proc_map_in_rval(Rval, StdRval, DupProcMap) :-
(
( Rval = lval(_)
; Rval = mkword(_, _)
; Rval = mkword_hole(_)
; Rval = mem_addr(_)
),
StdRval = Rval
;
Rval = var(_),
unexpected($pred, "var")
;
Rval = const(Const),
apply_dup_proc_map_in_rval_const(Const, StdConst, DupProcMap),
StdRval = const(StdConst)
;
Rval = cast(Type, RvalL),
apply_dup_proc_map_in_rval(RvalL, StdRvalL, DupProcMap),
StdRval = cast(Type, StdRvalL)
;
Rval = unop(Unop, RvalL),
apply_dup_proc_map_in_rval(RvalL, StdRvalL, DupProcMap),
StdRval = unop(Unop, StdRvalL)
;
Rval = binop(Binop, RvalL, RvalR),
apply_dup_proc_map_in_rval(RvalL, StdRvalL, DupProcMap),
apply_dup_proc_map_in_rval(RvalR, StdRvalR, DupProcMap),
StdRval = binop(Binop, StdRvalL, StdRvalR)
).
% Compute the standard form of an rval constant.
%
:- pred apply_dup_proc_map_in_rval_const(rval_const::in, rval_const::out,
map(proc_label, proc_label)::in) is det.
apply_dup_proc_map_in_rval_const(Const, StdConst, DupProcMap) :-
(
( Const = llconst_true
; Const = llconst_false
; Const = llconst_int(_)
; Const = llconst_uint(_)
; Const = llconst_int8(_)
; Const = llconst_uint8(_)
; Const = llconst_int16(_)
; Const = llconst_uint16(_)
; Const = llconst_int32(_)
; Const = llconst_uint32(_)
; Const = llconst_int64(_)
; Const = llconst_uint64(_)
; Const = llconst_foreign(_, _)
; Const = llconst_float(_)
; Const = llconst_string(_)
; Const = llconst_multi_string(_)
; Const = llconst_data_addr(_, _)
),
StdConst = Const
;
Const = llconst_code_addr(CodeAddr),
apply_dup_proc_map_in_code_addr(CodeAddr, StdCodeAddr, DupProcMap),
StdConst = llconst_code_addr(StdCodeAddr)
).
%-----------------------------------------------------------------------------%
:- end_module ll_backend.dupproc.
%-----------------------------------------------------------------------------%