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+%% -*- erlang-indent-level: 2 -*-
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%% http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%@doc
+%% TEMPORARY LIVE RANGE SPLITTING PASS
+%%
+%% Live range splitting is useful to allow a register allocator to allocate a
+%% temporary to register for a part of its lifetime, even if it cannot be for
+%% the entirety. This improves register allocation quality, at the cost of
+%% making the allocation problem more time and memory intensive to solve.
+%%
+%% Optimal allocation can be achieved if all temporaries are split at every
+%% program point (between all instructions), but this makes register allocation
+%% infeasably slow in practice. Instead, this module uses heuristics to choose
+%% which temporaries should have their live ranges split, and at which points.
+%%
+%% The range splitter only considers temps which are live during a call
+%% instruction, since they're known to be spilled. The control-flow graph is
+%% partitioned at call instructions and splitting decisions are made separately
+%% for each partition. The register copy of a temp (if any) gets a separate name
+%% in each partition.
+%%
+%% There are three different ways the range splitter may choose to split a
+%% temporary in a program partition:
+%%
+%% * Mode1: Spill the temp before calls, and restore it after them
+%% * Mode2: Spill the temp after definitions, restore it after calls
+%% * Mode3: Spill the temp after definitions, restore it before uses
+%%
+%% To pick which of these should be used for each tempĂ—partiton pair, the range
+%% splitter uses a cost function. The cost is simply the sum of the cost of all
+%% expected stack accesses, and the cost for an individual stack access is based
+%% on the probability weight of the basic block that it resides in. This biases
+%% the range splitter so that it attempts moving stack accesses from a functions
+%% hot path to the cold path.
+%%
+%% The heuristic has a couple of tuning knobs, adjusting its preference for
+%% different spilling modes, aggressiveness, and how much influence the basic
+%% block probability weights have.
+%%
+%% Edge case not handled: Call instructions directly defining a pseudo. In that
+%% case, if that pseudo has been selected for mode2 spills, no spill is inserted
+%% after the call.
+-module(hipe_range_split).
+
+-export([split/5]).
+
+-compile(inline).
+
+%% -define(DO_ASSERT, 1).
+%% -define(DEBUG, 1).
+-include("../main/hipe.hrl").
+
+%% Heuristic tuning constants
+-define(DEFAULT_MIN_GAIN, 1.1). % option: range_split_min_gain
+-define(DEFAULT_MODE1_FUDGE, 1.1). % option: range_split_mode1_fudge
+-define(DEFAULT_WEIGHT_POWER, 2). % option: range_split_weight_power
+-define(WEIGHT_CONST_FUN(Power), math:log(Power)/math:log(100)).
+-define(WEIGHT_FUN(Wt, Const), math:pow(Wt, Const)).
+-define(HEUR_MAX_TEMPS, 20000).
+
+-type target_cfg() :: any().
+-type target_instr() :: any().
+-type target_temp() :: any().
+-type liveness() :: any().
+-type target_module() :: module().
+-type target_context() :: any().
+-type target() :: {target_module(), target_context()}.
+-type liveset() :: ordsets:ordset(temp()).
+-type temp() :: non_neg_integer().
+-type label() :: non_neg_integer().
+
+-spec split(target_cfg(), liveness(), target_module(), target_context(),
+ comp_options())
+ -> target_cfg().
+split(TCFG0, Liveness, TargetMod, TargetContext, Options) ->
+ Target = {TargetMod, TargetContext},
+ NoTemps = number_of_temporaries(TCFG0, Target),
+ if NoTemps > ?HEUR_MAX_TEMPS ->
+ ?debug_msg("~w: Too many temps (~w), falling back on restore_reuse.~n",
+ [?MODULE, NoTemps]),
+ hipe_restore_reuse:split(TCFG0, Liveness, TargetMod, TargetContext);
+ true ->
+ Wts = compute_weights(TCFG0, TargetMod, TargetContext, Options),
+ {CFG0, Temps} = convert(TCFG0, Target),
+ Avail = avail_analyse(TCFG0, Liveness, Target),
+ Defs = def_analyse(CFG0, TCFG0),
+ RDefs = rdef_analyse(CFG0),
+ PLive = plive_analyse(CFG0),
+ {CFG, DUCounts, Costs, DSets0} =
+ scan(CFG0, Liveness, PLive, Wts, Defs, RDefs, Avail, Target),
+ {DSets, _} = hipe_dsets:to_map(DSets0),
+ Renames = decide(DUCounts, Costs, Target, Options),
+ rewrite(CFG, TCFG0, Target, Liveness, PLive, Defs, Avail, DSets, Renames,
+ Temps)
+ end.
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Internal program representation
+%%
+%% Second pass: Convert cfg to internal representation
+
+-record(cfg, {
+ rpo_labels :: [label()],
+ bbs :: #{label() => bb()}
+ }).
+-type cfg() :: #cfg{}.
+
+cfg_bb(L, #cfg{bbs=BBS}) -> maps:get(L, BBS).
+
+cfg_postorder(#cfg{rpo_labels=RPO}) -> lists:reverse(RPO).
+
+-record(bb, {
+ code :: [code_elem()],
+ %% If the last instruction of code defines all allocatable registers
+ has_call :: boolean(),
+ succ :: [label()]
+ }).
+-type bb() :: #bb{}.
+-type code_elem() :: instr() | mode2_spills() | mode3_restores().
+
+bb_code(#bb{code=Code}) -> Code.
+bb_has_call(#bb{has_call=HasCall}) -> HasCall.
+bb_succ(#bb{succ=Succ}) -> Succ.
+
+bb_butlast(#bb{code=Code}) ->
+ bb_butlast_1(Code).
+
+bb_butlast_1([_Last]) -> [];
+bb_butlast_1([I|Is]) -> [I|bb_butlast_1(Is)].
+
+bb_last(#bb{code=Code}) -> lists:last(Code).
+
+-record(instr, {
+ i :: target_instr(),
+ def :: ordsets:ordset(temp()),
+ use :: ordsets:ordset(temp())
+ }).
+-type instr() :: #instr{}.
+
+-record(mode2_spills, {
+ temps :: ordsets:ordset(temp())
+ }).
+-type mode2_spills() :: #mode2_spills{}.
+
+-record(mode3_restores, {
+ temps :: ordsets:ordset(temp())
+ }).
+-type mode3_restores() :: #mode3_restores{}.
+
+-spec convert(target_cfg(), target()) -> {cfg(), temps()}.
+convert(CFG, Target) ->
+ RPO = reverse_postorder(CFG, Target),
+ {BBsList, Temps} = convert_bbs(RPO, CFG, Target, #{}, []),
+ {#cfg{rpo_labels = RPO,
+ bbs = maps:from_list(BBsList)},
+ Temps}.
+
+convert_bbs([], _CFG, _Target, Temps, Acc) -> {Acc, Temps};
+convert_bbs([L|Ls], CFG, Target, Temps0, Acc) ->
+ Succs = hipe_gen_cfg:succ(CFG, L),
+ TBB = bb(CFG, L, Target),
+ TCode = hipe_bb:code(TBB),
+ {Code, Last, Temps} = convert_code(TCode, Target, Temps0, []),
+ HasCall = defines_all_alloc(Last#instr.i, Target),
+ BB = #bb{code = Code,
+ has_call = HasCall,
+ succ = Succs},
+ convert_bbs(Ls, CFG, Target, Temps, [{L,BB}|Acc]).
+
+convert_code([], _Target, Temps, [Last|_]=Acc) ->
+ {lists:reverse(Acc), Last, Temps};
+convert_code([TI|TIs], Target, Temps0, Acc) ->
+ {TDef, TUse} = def_use(TI, Target),
+ I = #instr{i = TI,
+ def = ordsets:from_list(reg_names(TDef, Target)),
+ use = ordsets:from_list(reg_names(TUse, Target))},
+ Temps = add_temps(TUse, Target, add_temps(TDef, Target, Temps0)),
+ convert_code(TIs, Target, Temps, [I|Acc]).
+
+-type temps() :: #{temp() => target_temp()}.
+add_temps([], _Target, Temps) -> Temps;
+add_temps([T|Ts], Target, Temps) ->
+ add_temps(Ts, Target, Temps#{reg_nr(T, Target) => T}).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Fourth pass: P({DEF}) lattice fwd dataflow (for eliding stores at SPILL
+%% splits)
+-type defsi() :: #{label() => defseti() | {call, defseti(), defseti()}}.
+-type defs() :: #{label() => defsetf()}.
+
+-spec def_analyse(cfg(), target_cfg()) -> defs().
+def_analyse(CFG = #cfg{rpo_labels = RPO}, TCFG) ->
+ Defs0 = def_init(CFG),
+ def_dataf(RPO, TCFG, Defs0).
+
+-spec def_init(cfg()) -> defsi().
+def_init(#cfg{bbs = BBs}) ->
+ maps:from_list(
+ [begin
+ {L, case HasCall of
+ false -> def_init_scan(bb_code(BB), defseti_new());
+ true ->
+ {call, def_init_scan(bb_butlast(BB), defseti_new()),
+ defseti_from_ordset((bb_last(BB))#instr.def)}
+ end}
+ end || {L, BB = #bb{has_call=HasCall}} <- maps:to_list(BBs)]).
+
+def_init_scan([], Defset) -> Defset;
+def_init_scan([#instr{def=Def}|Is], Defset0) ->
+ Defset = defseti_add_ordset(Def, Defset0),
+ def_init_scan(Is, Defset).
+
+-spec def_dataf([label()], target_cfg(), defsi()) -> defs().
+def_dataf(Labels, TCFG, Defs0) ->
+ case def_dataf_once(Labels, TCFG, Defs0, 0) of
+ {Defs, 0} ->
+ def_finalise(Defs);
+ {Defs, _Changed} ->
+ def_dataf(Labels, TCFG, Defs)
+ end.
+
+-spec def_finalise(defsi()) -> defs().
+def_finalise(Defs) ->
+ maps:from_list([{K, defseti_finalise(BL)}
+ || {K, {call, BL, _}} <- maps:to_list(Defs)]).
+
+-spec def_dataf_once([label()], target_cfg(), defsi(), non_neg_integer())
+ -> {defsi(), non_neg_integer()}.
+def_dataf_once([], _TCFG, Defs, Changed) -> {Defs, Changed};
+def_dataf_once([L|Ls], TCFG, Defs0, Changed0) ->
+ AddPreds =
+ fun(Defset1) ->
+ lists:foldl(fun(P, Defset2) ->
+ defseti_union(defout(P, Defs0), Defset2)
+ end, Defset1, hipe_gen_cfg:pred(TCFG, L))
+ end,
+ Defset =
+ case Defset0 = maps:get(L, Defs0) of
+ {call, Butlast, Defout} -> {call, AddPreds(Butlast), Defout};
+ _ -> AddPreds(Defset0)
+ end,
+ Changed = case Defset =:= Defset0 of
+ true -> Changed0;
+ false -> Changed0+1
+ end,
+ def_dataf_once(Ls, TCFG, Defs0#{L := Defset}, Changed).
+
+-spec defout(label(), defsi()) -> defseti().
+defout(L, Defs) ->
+ case maps:get(L, Defs) of
+ {call, _DefButLast, Defout} -> Defout;
+ Defout -> Defout
+ end.
+
+-spec defbutlast(label(), defs()) -> defsetf().
+defbutlast(L, Defs) -> maps:get(L, Defs).
+
+-spec defseti_new() -> defseti().
+-spec defseti_union(defseti(), defseti()) -> defseti().
+-spec defseti_add_ordset(ordset:ordset(temp()), defseti()) -> defseti().
+-spec defseti_from_ordset(ordset:ordset(temp())) -> defseti().
+-spec defseti_finalise(defseti()) -> defsetf().
+-spec defsetf_member(temp(), defsetf()) -> boolean().
+-spec defsetf_intersect_ordset(ordsets:ordset(temp()), defsetf())
+ -> ordsets:ordset(temp()).
+
+-type defseti() :: bitord().
+defseti_new() -> bitord_new().
+defseti_union(A, B) -> bitord_union(A, B).
+defseti_add_ordset(OS, D) -> defseti_union(defseti_from_ordset(OS), D).
+defseti_from_ordset(OS) -> bitord_from_ordset(OS).
+defseti_finalise(D) -> bitarr_from_bitord(D).
+
+-type defsetf() :: bitarr().
+defsetf_member(E, D) -> bitarr_get(E, D).
+
+defsetf_intersect_ordset([], _D) -> [];
+defsetf_intersect_ordset([E|Es], D) ->
+ case bitarr_get(E, D) of
+ true -> [E|defsetf_intersect_ordset(Es,D)];
+ false -> defsetf_intersect_ordset(Es,D)
+ end.
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Fifth pass: P({DEF}) lattice reverse dataflow (for eliding stores at defines
+%% in mode2)
+-type rdefsi() :: #{label() =>
+ {call, rdefseti(), [label()]}
+ | {nocall, rdefseti(), rdefseti(), [label()]}}.
+-type rdefs() :: #{label() => {final, rdefsetf(), [label()]}}.
+
+-spec rdef_analyse(cfg()) -> rdefs().
+rdef_analyse(CFG = #cfg{rpo_labels=RPO}) ->
+ Defs0 = rdef_init(CFG),
+ PO = rdef_postorder(RPO, CFG, []),
+ rdef_dataf(PO, Defs0).
+
+%% Filter out 'call' labels, since they don't change
+-spec rdef_postorder([label()], cfg(), [label()]) -> [label()].
+rdef_postorder([], _CFG, Acc) -> Acc;
+rdef_postorder([L|Ls], CFG, Acc) ->
+ case bb_has_call(cfg_bb(L, CFG)) of
+ true -> rdef_postorder(Ls, CFG, Acc);
+ false -> rdef_postorder(Ls, CFG, [L|Acc])
+ end.
+
+-spec rdef_init(cfg()) -> rdefsi().
+rdef_init(#cfg{bbs = BBs}) ->
+ maps:from_list(
+ [{L, case HasCall of
+ true ->
+ Defin = rdef_init_scan(bb_butlast(BB), rdefseti_empty()),
+ {call, Defin, Succs};
+ false ->
+ Gen = rdef_init_scan(bb_code(BB), rdefseti_empty()),
+ {nocall, Gen, rdefseti_top(), Succs}
+ end}
+ || {L, BB = #bb{has_call=HasCall, succ=Succs}} <- maps:to_list(BBs)]).
+
+-spec rdef_init_scan([instr()], rdefseti()) -> rdefseti().
+rdef_init_scan([], Defset) -> Defset;
+rdef_init_scan([#instr{def=Def}|Is], Defset0) ->
+ Defset = rdefseti_add_ordset(Def, Defset0),
+ rdef_init_scan(Is, Defset).
+
+-spec rdef_dataf([label()], rdefsi()) -> rdefs().
+rdef_dataf(Labels, Defs0) ->
+ case rdef_dataf_once(Labels, Defs0, 0) of
+ {Defs, 0} ->
+ rdef_finalise(Defs);
+ {Defs, _Changed} ->
+ rdef_dataf(Labels, Defs)
+ end.
+
+-spec rdef_finalise(rdefsi()) -> rdefs().
+rdef_finalise(Defs) ->
+ maps:map(fun(L, V) ->
+ Succs = rsuccs_val(V),
+ Defout0 = rdefout_intersect(L, Defs, rdefseti_top()),
+ {final, rdefset_finalise(Defout0), Succs}
+ end, Defs).
+
+-spec rdef_dataf_once([label()], rdefsi(), non_neg_integer())
+ -> {rdefsi(), non_neg_integer()}.
+rdef_dataf_once([], Defs, Changed) -> {Defs, Changed};
+rdef_dataf_once([L|Ls], Defs0, Changed0) ->
+ #{L := {nocall, Gen, Defin0, Succs}} = Defs0,
+ Defin = rdefseti_union(Gen, rdefout_intersect(L, Defs0, Defin0)),
+ Defset = {nocall, Gen, Defin, Succs},
+ Changed = case Defin =:= Defin0 of
+ true -> Changed0;
+ false -> Changed0+1
+ end,
+ rdef_dataf_once(Ls, Defs0#{L := Defset}, Changed).
+
+-spec rdefin(label(), rdefsi()) -> rdefseti().
+rdefin(L, Defs) -> rdefin_val(maps:get(L, Defs)).
+rdefin_val({nocall, _Gen, Defin, _Succs}) -> Defin;
+rdefin_val({call, Defin, _Succs}) -> Defin.
+
+-spec rsuccs(label(), rdefsi()) -> [label()].
+rsuccs(L, Defs) -> rsuccs_val(maps:get(L, Defs)).
+rsuccs_val({nocall, _Gen, _Defin, Succs}) -> Succs;
+rsuccs_val({call, _Defin, Succs}) -> Succs.
+
+-spec rdefout(label(), rdefs()) -> rdefsetf().
+rdefout(L, Defs) ->
+ #{L := {final, Defout, _Succs}} = Defs,
+ Defout.
+
+-spec rdefout_intersect(label(), rdefsi(), rdefseti()) -> rdefseti().
+rdefout_intersect(L, Defs, Init) ->
+ lists:foldl(fun(S, Acc) ->
+ rdefseti_intersect(rdefin(S, Defs), Acc)
+ end, Init, rsuccs(L, Defs)).
+
+-type rdefseti() :: bitord() | top.
+rdefseti_top() -> top.
+rdefseti_empty() -> bitord_new().
+-spec rdefseti_from_ordset(ordsets:ordset(temp())) -> rdefseti().
+rdefseti_from_ordset(OS) -> bitord_from_ordset(OS).
+
+-spec rdefseti_add_ordset(ordsets:ordset(temp()), rdefseti()) -> rdefseti().
+rdefseti_add_ordset(_, top) -> top; % Should never happen in rdef_dataf
+rdefseti_add_ordset(OS, D) -> rdefseti_union(rdefseti_from_ordset(OS), D).
+
+-spec rdefseti_union(rdefseti(), rdefseti()) -> rdefseti().
+rdefseti_union(top, _) -> top;
+rdefseti_union(_, top) -> top;
+rdefseti_union(A, B) -> bitord_union(A, B).
+
+-spec rdefseti_intersect(rdefseti(), rdefseti()) -> rdefseti().
+rdefseti_intersect(top, D) -> D;
+rdefseti_intersect(D, top) -> D;
+rdefseti_intersect(A, B) -> bitord_intersect(A, B).
+
+-type rdefsetf() :: {arr, bitarr()} | top.
+-spec rdefset_finalise(rdefseti()) -> rdefsetf().
+rdefset_finalise(top) -> top;
+rdefset_finalise(Ord) -> {arr, bitarr_from_bitord(Ord)}.
+
+%% rdefsetf_top() -> top.
+rdefsetf_empty() -> {arr, bitarr_new()}.
+
+-spec rdefsetf_add_ordset(ordset:ordset(temp()), rdefsetf()) -> rdefsetf().
+rdefsetf_add_ordset(_, top) -> top;
+rdefsetf_add_ordset(OS, {arr, Arr}) ->
+ {arr, lists:foldl(fun bitarr_set/2, Arr, OS)}.
+
+-spec rdef_step(instr(), rdefsetf()) -> rdefsetf().
+rdef_step(#instr{def=Def}, Defset) ->
+ %% ?ASSERT(not defines_all_alloc(I, Target)),
+ rdefsetf_add_ordset(Def, Defset).
+
+-spec ordset_subtract_rdefsetf(ordsets:ordset(temp()), rdefsetf())
+ -> ordsets:ordset(temp()).
+ordset_subtract_rdefsetf(_, top) -> [];
+ordset_subtract_rdefsetf(OS, {arr, Arr}) ->
+ %% Lazy implementation; could do better if OS can grow
+ lists:filter(fun(E) -> not bitarr_get(E, Arr) end, OS).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Integer sets represented as bit sets
+%%
+%% Two representations; bitord() and bitarr()
+-define(LIMB_IX_BITS, 11).
+-define(LIMB_BITS, (1 bsl ?LIMB_IX_BITS)).
+-define(LIMB_IX(Index), (Index bsr ?LIMB_IX_BITS)).
+-define(BIT_IX(Index), (Index band (?LIMB_BITS - 1))).
+-define(BIT_MASK(Index), (1 bsl ?BIT_IX(Index))).
+
+%% bitord(): fast at union/2 and can be compared for equality with '=:='
+-type bitord() :: orddict:orddict(non_neg_integer(), 0..((1 bsl ?LIMB_BITS)-1)).
+
+-spec bitord_new() -> bitord().
+bitord_new() -> [].
+
+-spec bitord_union(bitord(), bitord()) -> bitord().
+bitord_union(Lhs, Rhs) ->
+ orddict:merge(fun(_, L, R) -> L bor R end, Lhs, Rhs).
+
+-spec bitord_intersect(bitord(), bitord()) -> bitord().
+bitord_intersect([], _) -> [];
+bitord_intersect(_, []) -> [];
+bitord_intersect([{K, L}|Ls], [{K, R}|Rs]) ->
+ [{K, L band R} | bitord_intersect(Ls, Rs)];
+bitord_intersect([{LK, _}|Ls], [{RK, _}|_]=Rs) when LK < RK ->
+ bitord_intersect(Ls, Rs);
+bitord_intersect([{LK, _}|_]=Ls, [{RK, _}|Rs]) when LK > RK ->
+ bitord_intersect(Ls, Rs).
+
+-spec bitord_from_ordset(ordsets:ordset(non_neg_integer())) -> bitord().
+bitord_from_ordset([]) -> [];
+bitord_from_ordset([B|Bs]) ->
+ bitord_from_ordset_1(Bs, ?LIMB_IX(B), ?BIT_MASK(B)).
+
+bitord_from_ordset_1([B|Bs], Key, Val) when Key =:= ?LIMB_IX(B) ->
+ bitord_from_ordset_1(Bs, Key, Val bor ?BIT_MASK(B));
+bitord_from_ordset_1([B|Bs], Key, Val) ->
+ [{Key,Val} | bitord_from_ordset_1(Bs, ?LIMB_IX(B), ?BIT_MASK(B))];
+bitord_from_ordset_1([], Key, Val) -> [{Key, Val}].
+
+%% bitarr(): fast (enough) at get/2
+-type bitarr() :: array:array(0..((1 bsl ?LIMB_BITS)-1)).
+
+-spec bitarr_new() -> bitarr().
+bitarr_new() -> array:new({default, 0}).
+
+-spec bitarr_get(non_neg_integer(), bitarr()) -> boolean().
+bitarr_get(Index, Array) ->
+ Limb = array:get(?LIMB_IX(Index), Array),
+ 0 =/= (Limb band ?BIT_MASK(Index)).
+
+-spec bitarr_set(non_neg_integer(), bitarr()) -> bitarr().
+bitarr_set(Index, Array) ->
+ Limb0 = array:get(?LIMB_IX(Index), Array),
+ Limb = Limb0 bor ?BIT_MASK(Index),
+ array:set(?LIMB_IX(Index), Limb, Array).
+
+-spec bitarr_from_bitord(bitord()) -> bitarr().
+bitarr_from_bitord(Ord) ->
+ array:from_orddict(Ord, 0).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Sixth pass: Partition-local liveness analysis
+%%
+%% As temps are not spilled when exiting a partition in mode2, only
+%% partition-local uses need to be considered when deciding which temps need
+%% restoring at partition entry.
+
+-type plive() :: #{label() =>
+ {call, liveset(), [label()]}
+ | {nocall, {liveset(), liveset()}, liveset(), [label()]}}.
+
+-spec plive_analyse(cfg()) -> plive().
+plive_analyse(CFG) ->
+ Defs0 = plive_init(CFG),
+ PO = cfg_postorder(CFG),
+ plive_dataf(PO, Defs0).
+
+-spec plive_init(cfg()) -> plive().
+plive_init(#cfg{bbs = BBs}) ->
+ maps:from_list(
+ [begin
+ {L, case HasCall of
+ true ->
+ {Gen, _} = plive_init_scan(bb_code(BB)),
+ {call, Gen, Succs};
+ false ->
+ GenKill = plive_init_scan(bb_code(BB)),
+ {nocall, GenKill, liveset_empty(), Succs}
+ end}
+ end || {L, BB = #bb{has_call=HasCall, succ=Succs}} <- maps:to_list(BBs)]).
+
+-spec plive_init_scan([instr()]) -> {liveset(), liveset()}.
+plive_init_scan([]) -> {liveset_empty(), liveset_empty()};
+plive_init_scan([#instr{def=InstrKill, use=InstrGen}|Is]) ->
+ {Gen0, Kill0} = plive_init_scan(Is),
+ Gen1 = liveset_subtract(Gen0, InstrKill),
+ Gen = liveset_union(Gen1, InstrGen),
+ Kill1 = liveset_union(Kill0, InstrKill),
+ Kill = liveset_subtract(Kill1, InstrGen),
+ {Gen, Kill}.
+
+-spec plive_dataf([label()], plive()) -> plive().
+plive_dataf(Labels, PLive0) ->
+ case plive_dataf_once(Labels, PLive0, 0) of
+ {PLive, 0} -> PLive;
+ {PLive, _Changed} ->
+ plive_dataf(Labels, PLive)
+ end.
+
+-spec plive_dataf_once([label()], plive(), non_neg_integer()) ->
+ {plive(), non_neg_integer()}.
+plive_dataf_once([], PLive, Changed) -> {PLive, Changed};
+plive_dataf_once([L|Ls], PLive0, Changed0) ->
+ Liveset =
+ case Liveset0 = maps:get(L, PLive0) of
+ {call, Livein, Succs} ->
+ {call, Livein, Succs};
+ {nocall, {Gen, Kill} = GenKill, _OldLivein, Succs} ->
+ Liveout = pliveout(L, PLive0),
+ Livein = liveset_union(Gen, liveset_subtract(Liveout, Kill)),
+ {nocall, GenKill, Livein, Succs}
+ end,
+ Changed = case Liveset =:= Liveset0 of
+ true -> Changed0;
+ false -> Changed0+1
+ end,
+ plive_dataf_once(Ls, PLive0#{L := Liveset}, Changed).
+
+-spec pliveout(label(), plive()) -> liveset().
+pliveout(L, PLive) ->
+ liveset_union([plivein(S, PLive) || S <- psuccs(L, PLive)]).
+
+-spec psuccs(label(), plive()) -> [label()].
+psuccs(L, PLive) -> psuccs_val(maps:get(L, PLive)).
+psuccs_val({call, _Livein, Succs}) -> Succs;
+psuccs_val({nocall, _GenKill, _Livein, Succs}) -> Succs.
+
+-spec plivein(label(), plive()) -> liveset().
+plivein(L, PLive) -> plivein_val(maps:get(L, PLive)).
+plivein_val({call, Livein, _Succs}) -> Livein;
+plivein_val({nocall, _GenKill, Livein, _Succs}) -> Livein.
+
+liveset_empty() -> ordsets:new().
+liveset_subtract(A, B) -> ordsets:subtract(A, B).
+liveset_union(A, B) -> ordsets:union(A, B).
+liveset_union(LivesetList) -> ordsets:union(LivesetList).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Third pass: Compute dataflow analyses required for placing mode3
+%% spills/restores.
+%% Reuse analysis implementation in hipe_restore_reuse.
+%% XXX: hipe_restore_reuse has it's own "rdef"; we would like to reuse that one
+%% too.
+-type avail() :: hipe_restore_reuse:avail().
+
+-spec avail_analyse(target_cfg(), liveness(), target()) -> avail().
+avail_analyse(CFG, Liveness, Target) ->
+ hipe_restore_reuse:analyse(CFG, Liveness, Target).
+
+-spec mode3_split_in_block(label(), avail()) -> ordsets:ordset(temp()).
+mode3_split_in_block(L, Avail) ->
+ hipe_restore_reuse:split_in_block(L, Avail).
+
+-spec mode3_block_renameset(label(), avail()) -> ordsets:ordset(temp()).
+mode3_block_renameset(L, Avail) ->
+ hipe_restore_reuse:renamed_in_block(L, Avail).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Seventh pass
+%%
+%% Compute program space partitioning, collect information required by the
+%% heuristic.
+-type part_key() :: label().
+-type part_dsets() :: hipe_dsets:dsets(part_key()).
+-type part_dsets_map() :: #{part_key() => part_key()}.
+-type ducounts() :: #{part_key() => ducount()}.
+
+-spec scan(cfg(), liveness(), plive(), weights(), defs(), rdefs(), avail(),
+ target()) -> {cfg(), ducounts(), costs(), part_dsets()}.
+scan(CFG0, Liveness, PLive, Weights, Defs, RDefs, Avail, Target) ->
+ #cfg{rpo_labels = Labels, bbs = BBs0} = CFG0,
+ CFG = CFG0#cfg{bbs=#{}}, % kill reference
+ DSets0 = hipe_dsets:new(Labels),
+ Costs0 = costs_new(),
+ {BBs, DUCounts0, Costs1, DSets1} =
+ scan_bbs(maps:to_list(BBs0), Liveness, PLive, Weights, Defs, RDefs, Avail,
+ Target, #{}, Costs0, DSets0, []),
+ {RLList, DSets2} = hipe_dsets:to_rllist(DSets1),
+ {Costs, DSets} = costs_map_roots(DSets2, Costs1),
+ DUCounts = collect_ducounts(RLList, DUCounts0, #{}),
+ {CFG#cfg{bbs=maps:from_list(BBs)}, DUCounts, Costs, DSets}.
+
+-spec collect_ducounts([{label(), [label()]}], ducounts(), ducounts())
+ -> ducounts().
+collect_ducounts([], _, Acc) -> Acc;
+collect_ducounts([{R,Ls}|RLs], DUCounts, Acc) ->
+ DUCount = lists:foldl(
+ fun(Key, FAcc) ->
+ ducount_merge(maps:get(Key, DUCounts, ducount_new()), FAcc)
+ end, ducount_new(), Ls),
+ collect_ducounts(RLs, DUCounts, Acc#{R => DUCount}).
+
+-spec scan_bbs([{label(), bb()}], liveness(), plive(), weights(), defs(),
+ rdefs(), avail(), target(), ducounts(), costs(), part_dsets(),
+ [{label(), bb()}])
+ -> {[{label(), bb()}], ducounts(), costs(), part_dsets()}.
+scan_bbs([], _Liveness, _PLive, _Weights, _Defs, _RDefs, _Avail, _Target,
+ DUCounts, Costs, DSets, Acc) ->
+ {Acc, DUCounts, Costs, DSets};
+scan_bbs([{L,BB}|BBs], Liveness, PLive, Weights, Defs, RDefs, Avail, Target,
+ DUCounts0, Costs0, DSets0, Acc) ->
+ Wt = weight(L, Weights),
+ {DSets, Costs5, EntryCode, ExitCode, RDefout, Liveout} =
+ case bb_has_call(BB) of
+ false ->
+ DSets1 = lists:foldl(fun(S, DS) -> hipe_dsets:union(L, S, DS) end,
+ DSets0, bb_succ(BB)),
+ {DSets1, Costs0, bb_code(BB), [], rdefout(L, RDefs),
+ liveout(Liveness, L, Target)};
+ true ->
+ LastI = #instr{def=LastDef} = bb_last(BB),
+ LiveBefore = ordsets:subtract(liveout(Liveness, L, Target), LastDef),
+ %% We can omit the spill of a temp that has not been defined since the
+ %% last time it was spilled
+ SpillSet = defsetf_intersect_ordset(LiveBefore, defbutlast(L, Defs)),
+ Costs1 = costs_insert(exit, L, Wt, SpillSet, Costs0),
+ Costs4 = lists:foldl(fun({S, BranchWt}, Costs2) ->
+ SLivein = livein(Liveness, S, Target),
+ SPLivein = plivein(S, PLive),
+ SWt = weight_scaled(L, BranchWt, Weights),
+ Costs3 = costs_insert(entry1, S, SWt, SLivein, Costs2),
+ costs_insert(entry2, S, SWt, SPLivein, Costs3)
+ end, Costs1, branch_preds(LastI#instr.i, Target)),
+ {DSets0, Costs4, bb_butlast(BB), [LastI], rdefsetf_empty(), LiveBefore}
+ end,
+ Mode3Splits = mode3_split_in_block(L, Avail),
+ {RevEntryCode, Restored} = scan_bb_fwd(EntryCode, Mode3Splits, [], []),
+ {Code, DUCount, Mode2Spills} =
+ scan_bb(RevEntryCode, Wt, RDefout, Liveout, ducount_new(), [], ExitCode),
+ DUCounts = DUCounts0#{L => DUCount},
+ M2SpillSet = ordsets:from_list(Mode2Spills),
+ Costs6 = costs_insert(spill, L, Wt, M2SpillSet, Costs5),
+ Mode3Renames = mode3_block_renameset(L, Avail),
+ Costs7 = costs_insert(restore, L, Wt, ordsets:intersection(M2SpillSet, Mode3Renames), Costs6),
+ Costs8 = costs_insert(restore, L, Wt, ordsets:from_list(Restored), Costs7),
+ Costs = add_unsplit_mode3_costs(DUCount, Mode3Renames, L, Costs8),
+ scan_bbs(BBs, Liveness, PLive, Weights, Defs, RDefs, Avail, Target, DUCounts,
+ Costs, DSets, [{L,BB#bb{code=Code}}|Acc]).
+
+-spec add_unsplit_mode3_costs(ducount(), ordsets:ordset(temp()), label(), costs())
+ -> costs().
+add_unsplit_mode3_costs(DUCount, Mode3Renames, L, Costs) ->
+ Unsplit = orddict_without_ordset(Mode3Renames,
+ orddict:from_list(ducount_to_list(DUCount))),
+ add_unsplit_mode3_costs_1(Unsplit, L, Costs).
+
+-spec add_unsplit_mode3_costs_1([{temp(),float()}], label(), costs())
+ -> costs().
+add_unsplit_mode3_costs_1([], _L, Costs) -> Costs;
+add_unsplit_mode3_costs_1([{T,C}|Cs], L, Costs) ->
+ add_unsplit_mode3_costs_1(Cs, L, costs_insert(restore, L, C, [T], Costs)).
+
+%% @doc Returns a new orddict without keys in Set and their associated values.
+-spec orddict_without_ordset(ordsets:ordset(K), orddict:orddict(K, V))
+ -> orddict:orddict(K, V).
+orddict_without_ordset([S|Ss], [{K,_}|_]=Dict) when S < K ->
+ orddict_without_ordset(Ss, Dict);
+orddict_without_ordset([S|_]=Set, [D={K,_}|Ds]) when S > K ->
+ [D|orddict_without_ordset(Set, Ds)];
+orddict_without_ordset([_S|Ss], [{_K,_}|Ds]) -> % _S == _K
+ orddict_without_ordset(Ss, Ds);
+orddict_without_ordset(_, []) -> [];
+orddict_without_ordset([], Dict) -> Dict.
+
+%% Scans the code forward, collecting and inserting mode3 restores
+-spec scan_bb_fwd([instr()], ordsets:ordset(temp()), ordsets:ordset(temp()),
+ [code_elem()])
+ -> {[code_elem()], ordsets:ordset(temp())}.
+scan_bb_fwd([], [], Restored, Acc) -> {Acc, Restored};
+scan_bb_fwd([I|Is], SplitHere0, Restored0, Acc0) ->
+ #instr{def=Def, use=Use} = I,
+ {ToRestore, SplitHere1} =
+ lists:partition(fun(R) -> lists:member(R, Use) end, SplitHere0),
+ SplitHere = lists:filter(fun(R) -> not lists:member(R, Def) end, SplitHere1),
+ Acc =
+ case ToRestore of
+ [] -> [I | Acc0];
+ _ -> [I, #mode3_restores{temps=ToRestore} | Acc0]
+ end,
+ scan_bb_fwd(Is, SplitHere, ToRestore ++ Restored0, Acc).
+
+%% Scans the code backwards, collecting def/use counts and mode2 spills
+-spec scan_bb([code_elem()], float(), rdefsetf(), liveset(), ducount(),
+ [temp()], [code_elem()])
+ -> {[code_elem()], ducount(), [temp()]}.
+scan_bb([], _Wt, _RDefout, _Liveout, DUCount, Spills, Acc) ->
+ {Acc, DUCount, Spills};
+scan_bb([I=#mode3_restores{}|Is], Wt, RDefout, Liveout, DUCount, Spills, Acc) ->
+ scan_bb(Is, Wt, RDefout, Liveout, DUCount, Spills, [I|Acc]);
+scan_bb([I|Is], Wt, RDefout, Liveout, DUCount0, Spills0, Acc0) ->
+ #instr{def=Def,use=Use} = I,
+ DUCount = ducount_add(Use, Wt, ducount_add(Def, Wt, DUCount0)),
+ Livein = liveness_step(I, Liveout),
+ RDefin = rdef_step(I, RDefout),
+ %% The temps that would be spilled after I in mode 2
+ NewSpills = ordset_subtract_rdefsetf(
+ ordsets:intersection(Def, Liveout),
+ RDefout),
+ ?ASSERT(NewSpills =:= (NewSpills -- Spills0)),
+ Spills = NewSpills ++ Spills0,
+ Acc1 = case NewSpills of
+ [] -> Acc0;
+ _ -> [#mode2_spills{temps=NewSpills}|Acc0]
+ end,
+ scan_bb(Is, Wt, RDefin, Livein, DUCount, Spills, [I|Acc1]).
+
+-spec liveness_step(instr(), liveset()) -> liveset().
+liveness_step(#instr{def=Def, use=Use}, Liveout) ->
+ ordsets:union(Use, ordsets:subtract(Liveout, Def)).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% First pass: compute basic-block weighting
+
+-type weights() :: no_bb_weights
+ | {hipe_bb_weights:bb_weights(), float()}.
+
+-spec weight(label(), weights()) -> float().
+weight(L, Weights) -> weight_scaled(L, 1.0, Weights).
+
+-spec compute_weights(target_cfg(), target_module(), target_context(),
+ comp_options()) -> weights().
+compute_weights(CFG, TargetMod, TargetContext, Options) ->
+ case proplists:get_bool(range_split_weights, Options) of
+ false -> no_bb_weights;
+ true ->
+ {hipe_bb_weights:compute(CFG, TargetMod, TargetContext),
+ ?WEIGHT_CONST_FUN(proplists:get_value(range_split_weight_power,
+ Options, ?DEFAULT_WEIGHT_POWER))}
+ end.
+
+-spec weight_scaled(label(), float(), weights()) -> float().
+weight_scaled(_L, _Scale, no_bb_weights) -> 1.0;
+weight_scaled(L, Scale, {Weights, Const}) ->
+ Wt0 = hipe_bb_weights:weight(L, Weights) * Scale,
+ Wt = erlang:min(erlang:max(Wt0, 0.0000000000000000001), 10000.0),
+ ?WEIGHT_FUN(Wt, Const).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Heuristic splitting decision.
+%%
+%% Decide which temps to split, in which parts, and pick new names for them.
+-type spill_mode() :: mode1 % Spill temps at partition exits
+ | mode2 % Spill temps at definitions
+ | mode3.% Spill temps at definitions, restore temps at uses
+-type ren() :: #{temp() => {spill_mode(), temp()}}.
+-type renames() :: #{label() => ren()}.
+
+-record(heur_par, {
+ mode1_fudge :: float(),
+ min_gain :: float()
+ }).
+-type heur_par() :: #heur_par{}.
+
+-spec decide(ducounts(), costs(), target(), comp_options()) -> renames().
+decide(DUCounts, Costs, Target, Options) ->
+ Par = #heur_par{
+ mode1_fudge = proplists:get_value(range_split_mode1_fudge, Options,
+ ?DEFAULT_MODE1_FUDGE),
+ min_gain = proplists:get_value(range_split_min_gain, Options,
+ ?DEFAULT_MIN_GAIN)},
+ decide_parts(maps:to_list(DUCounts), Costs, Target, Par, #{}).
+
+-spec decide_parts([{part_key(), ducount()}], costs(), target(),
+ heur_par(), renames())
+ -> renames().
+decide_parts([], _Costs, _Target, _Par, Acc) -> Acc;
+decide_parts([{Part,DUCount}|Ps], Costs, Target, Par, Acc) ->
+ Spills = decide_temps(ducount_to_list(DUCount), Part, Costs, Target, Par,
+ #{}),
+ decide_parts(Ps, Costs, Target, Par, Acc#{Part => Spills}).
+
+-spec decide_temps([{temp(), float()}], part_key(), costs(), target(),
+ heur_par(), ren())
+ -> ren().
+decide_temps([], _Part, _Costs, _Target, _Par, Acc) -> Acc;
+decide_temps([{Temp, SpillGain}|Ts], Part, Costs, Target, Par, Acc0) ->
+ SpillCost1 = costs_query(Temp, entry1, Part, Costs)
+ + costs_query(Temp, exit, Part, Costs),
+ SpillCost2 = costs_query(Temp, entry2, Part, Costs)
+ + costs_query(Temp, spill, Part, Costs),
+ SpillCost3 = costs_query(Temp, restore, Part, Costs),
+ Acc =
+ %% SpillCost1 =:= 0.0 usually means the temp is local to the partition;
+ %% hence no need to split it
+ case (SpillCost1 =/= 0.0) %% maps:is_key(Temp, S)
+ andalso (not is_precoloured(Temp, Target))
+ andalso ((Par#heur_par.min_gain*SpillCost1 < SpillGain)
+ orelse (Par#heur_par.min_gain*SpillCost2 < SpillGain)
+ orelse (Par#heur_par.min_gain*SpillCost3 < SpillGain))
+ of
+ false -> Acc0;
+ true ->
+ Mode =
+ if Par#heur_par.mode1_fudge*SpillCost1 < SpillCost2,
+ Par#heur_par.mode1_fudge*SpillCost1 < SpillCost3 ->
+ mode1;
+ SpillCost2 < SpillCost3 ->
+ mode2;
+ true ->
+ mode3
+ end,
+ Acc0#{Temp => {Mode, new_reg_nr(Target)}}
+ end,
+ decide_temps(Ts, Part, Costs, Target, Par, Acc).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Eighth pass: Rewrite program performing range splitting.
+
+-spec rewrite(cfg(), target_cfg(), target(), liveness(), plive(), defs(),
+ avail(), part_dsets_map(), renames(), temps())
+ -> target_cfg().
+rewrite(#cfg{bbs=BBs}, TCFG, Target, Liveness, PLive, Defs, Avail, DSets,
+ Renames, Temps) ->
+ rewrite_bbs(maps:to_list(BBs), Target, Liveness, PLive, Defs, Avail, DSets,
+ Renames, Temps, TCFG).
+
+-spec rewrite_bbs([{label(), bb()}], target(), liveness(), plive(), defs(),
+ avail(), part_dsets_map(), renames(), temps(), target_cfg())
+ -> target_cfg().
+rewrite_bbs([], _Target, _Liveness, _PLive, _Defs, _Avail, _DSets, _Renames,
+ _Temps, TCFG) ->
+ TCFG;
+rewrite_bbs([{L,BB}|BBs], Target, Liveness, PLive, Defs, Avail, DSets, Renames,
+ Temps, TCFG0) ->
+ Code0Rev = lists:reverse(bb_code(BB)),
+ EntryRen = maps:get(maps:get(L,DSets), Renames),
+ M3Ren = mode3_block_renameset(L, Avail),
+ SubstFun = rewrite_subst_fun(Target, EntryRen, M3Ren),
+ Fun = fun(I) -> subst_temps(SubstFun, I, Target) end,
+ {Code, TCFG} =
+ case bb_has_call(BB) of
+ false ->
+ Code1 = rewrite_instrs(Code0Rev, Fun, EntryRen, M3Ren, Temps, Target,
+ []),
+ {Code1, TCFG0};
+ true ->
+ CallI0 = hd(Code0Rev),
+ Succ = bb_succ(BB),
+ {CallTI, TCFG1} = inject_restores(Succ, Target, Liveness, PLive, DSets,
+ Renames, Temps, CallI0#instr.i, TCFG0),
+ Liveout1 = liveness_step(CallI0, liveout(Liveness, L, Target)),
+ Defout = defbutlast(L, Defs),
+ SpillMap = mk_spillmap(EntryRen, Liveout1, Defout, Temps, Target),
+ Code1 = rewrite_instrs(tl(Code0Rev), Fun, EntryRen, M3Ren, Temps,
+ Target, []),
+ Code2 = lift_spills(lists:reverse(Code1), Target, SpillMap, [CallTI]),
+ {Code2, TCFG1}
+ end,
+ TBB = hipe_bb:code_update(bb(TCFG, L, Target), Code),
+ rewrite_bbs(BBs, Target, Liveness, PLive, Defs, Avail, DSets, Renames, Temps,
+ update_bb(TCFG, L, TBB, Target)).
+
+-spec rewrite_instrs([code_elem()], rewrite_fun(), ren(),
+ ordsets:ordset(temp()), temps(), target(),
+ [target_instr()])
+ -> [target_instr()].
+rewrite_instrs([], _Fun, _Ren, _M3Ren, _Temps, _Target, Acc) -> Acc;
+rewrite_instrs([I|Is], Fun, Ren, M3Ren, Temps, Target, Acc0) ->
+ Acc =
+ case I of
+ #instr{i=TI} -> [Fun(TI)|Acc0];
+ #mode2_spills{temps=Mode2Spills} ->
+ add_mode2_spills(Mode2Spills, Target, Ren, M3Ren, Temps, Acc0);
+ #mode3_restores{temps=Mode3Restores} ->
+ add_mode3_restores(Mode3Restores, Target, Ren, Temps, Acc0)
+ end,
+ rewrite_instrs(Is, Fun, Ren, M3Ren, Temps, Target, Acc).
+
+-spec add_mode2_spills(ordsets:ordset(temp()), target(), ren(),
+ ordsets:ordset(temp()), temps(), [target_instr()])
+ -> [target_instr()].
+add_mode2_spills([], _Target, _Ren, _M3Ren, _Temps, Acc) -> Acc;
+add_mode2_spills([R|Rs], Target, Ren, M3Ren, Temps, Acc0) ->
+ Acc =
+ case Ren of
+ #{R := {Mode, NewName}} when Mode =:= mode2; Mode =:= mode3 ->
+ case Mode =/= mode3 orelse lists:member(R, M3Ren) of
+ false -> Acc0;
+ true ->
+ #{R := T} = Temps,
+ SpillInstr = mk_move(update_reg_nr(NewName, T, Target), T, Target),
+ [SpillInstr|Acc0]
+ end;
+ #{} ->
+ Acc0
+ end,
+ add_mode2_spills(Rs, Target, Ren, M3Ren, Temps, Acc).
+
+-spec add_mode3_restores(ordsets:ordset(temp()), target(), ren(), temps(),
+ [target_instr()])
+ -> [target_instr()].
+add_mode3_restores([], _Target, _Ren, _Temps, Acc) -> Acc;
+add_mode3_restores([R|Rs], Target, Ren, Temps, Acc) ->
+ case Ren of
+ #{R := {mode3, NewName}} ->
+ #{R := T} = Temps,
+ RestoreInstr = mk_move(T, update_reg_nr(NewName, T, Target), Target),
+ add_mode3_restores(Rs, Target, Ren, Temps, [RestoreInstr|Acc]);
+ #{} ->
+ add_mode3_restores(Rs, Target, Ren, Temps, Acc)
+ end.
+
+-type rewrite_fun() :: fun((target_instr()) -> target_instr()).
+-type subst_fun() :: fun((target_temp()) -> target_temp()).
+-spec rewrite_subst_fun(target(), ren(), ordsets:ordset(temp())) -> subst_fun().
+rewrite_subst_fun(Target, Ren, M3Ren) ->
+ fun(Temp) ->
+ Reg = reg_nr(Temp, Target),
+ case Ren of
+ #{Reg := {Mode, NewName}} ->
+ case Mode =/= mode3 orelse lists:member(Reg, M3Ren) of
+ false -> Temp;
+ true -> update_reg_nr(NewName, Temp, Target)
+ end;
+ #{} -> Temp
+ end
+ end.
+
+-type spillmap() :: [{temp(), target_instr()}].
+-spec mk_spillmap(ren(), liveset(), defsetf(), temps(), target())
+ -> spillmap().
+mk_spillmap(Ren, Livein, Defout, Temps, Target) ->
+ [begin
+ Temp = maps:get(Reg, Temps),
+ {NewName, mk_move(update_reg_nr(NewName, Temp, Target), Temp, Target)}
+ end || {Reg, {mode1, NewName}} <- maps:to_list(Ren),
+ lists:member(Reg, Livein), defsetf_member(Reg, Defout)].
+
+-spec mk_restores(ren(), liveset(), liveset(), temps(), target())
+ -> [target_instr()].
+mk_restores(Ren, Livein, PLivein, Temps, Target) ->
+ [begin
+ Temp = maps:get(Reg, Temps),
+ mk_move(Temp, update_reg_nr(NewName, Temp, Target), Target)
+ end || {Reg, {Mode, NewName}} <- maps:to_list(Ren),
+ ( (Mode =:= mode1 andalso lists:member(Reg, Livein ))
+ orelse (Mode =:= mode2 andalso lists:member(Reg, PLivein)))].
+
+-spec inject_restores([label()], target(), liveness(), plive(),
+ part_dsets_map(), renames(), temps(), target_instr(),
+ target_cfg())
+ -> {target_instr(), target_cfg()}.
+inject_restores([], _Target, _Liveness, _PLive, _DSets, _Renames, _Temps, CFTI,
+ TCFG) ->
+ {CFTI, TCFG};
+inject_restores([L|Ls], Target, Liveness, PLive, DSets, Renames, Temps, CFTI0,
+ TCFG0) ->
+ Ren = maps:get(maps:get(L,DSets), Renames),
+ Livein = livein(Liveness, L, Target),
+ PLivein = plivein(L, PLive),
+ {CFTI, TCFG} =
+ case mk_restores(Ren, Livein, PLivein, Temps, Target) of
+ [] -> {CFTI0, TCFG0}; % optimisation
+ Restores ->
+ RestBBLbl = new_label(Target),
+ Code = Restores ++ [mk_goto(L, Target)],
+ CFTI1 = redirect_jmp(CFTI0, L, RestBBLbl, Target),
+ TCFG1 = update_bb(TCFG0, RestBBLbl, hipe_bb:mk_bb(Code), Target),
+ {CFTI1, TCFG1}
+ end,
+ inject_restores(Ls, Target, Liveness, PLive, DSets, Renames, Temps, CFTI,
+ TCFG).
+
+%% Heuristic. Move spills up until we meet the edge of the BB or a definition of
+%% that temp.
+-spec lift_spills([target_instr()], target(), spillmap(), [target_instr()])
+ -> [target_instr()].
+lift_spills([], _Target, SpillMap, Acc) ->
+ [SpillI || {_, SpillI} <- SpillMap] ++ Acc;
+lift_spills([I|Is], Target, SpillMap0, Acc) ->
+ Def = reg_defines(I, Target),
+ {Spills0, SpillMap} =
+ lists:partition(fun({Reg,_}) -> lists:member(Reg, Def) end, SpillMap0),
+ Spills = [SpillI || {_, SpillI} <- Spills0],
+ lift_spills(Is, Target, SpillMap, [I|Spills ++ Acc]).
+
+reg_defines(I, Target) ->
+ reg_names(defines(I,Target), Target).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Costs ADT
+%%
+%% Keeps track of cumulative cost of spilling temps in particular partitions
+%% using particular spill modes.
+-type cost_map() :: #{[part_key()|temp()] => float()}.
+-type cost_key() :: entry1 | entry2 | exit | spill | restore.
+-record(costs, {entry1 = #{} :: cost_map()
+ ,entry2 = #{} :: cost_map()
+ ,exit = #{} :: cost_map()
+ ,spill = #{} :: cost_map()
+ ,restore = #{} :: cost_map()
+ }).
+-type costs() :: #costs{}.
+
+-spec costs_new() -> costs().
+costs_new() -> #costs{}.
+
+-spec costs_insert(cost_key(), part_key(), float(), liveset(), costs())
+ -> costs().
+costs_insert(entry1, A, Weight, Liveset, Costs=#costs{entry1=Entry1}) ->
+ Costs#costs{entry1=costs_insert_1(A, Weight, Liveset, Entry1)};
+costs_insert(entry2, A, Weight, Liveset, Costs=#costs{entry2=Entry2}) ->
+ Costs#costs{entry2=costs_insert_1(A, Weight, Liveset, Entry2)};
+costs_insert(exit, A, Weight, Liveset, Costs=#costs{exit=Exit}) ->
+ Costs#costs{exit=costs_insert_1(A, Weight, Liveset, Exit)};
+costs_insert(spill, A, Weight, Liveset, Costs=#costs{spill=Spill}) ->
+ Costs#costs{spill=costs_insert_1(A, Weight, Liveset, Spill)};
+costs_insert(restore, A, Weight, Liveset, Costs=#costs{restore=Restore}) ->
+ Costs#costs{restore=costs_insert_1(A, Weight, Liveset, Restore)}.
+
+costs_insert_1(A, Weight, Liveset, CostMap0) when is_float(Weight) ->
+ lists:foldl(fun(Live, CostMap1) ->
+ map_update_counter([A|Live], Weight, CostMap1)
+ end, CostMap0, Liveset).
+
+-spec costs_map_roots(part_dsets(), costs()) -> {costs(), part_dsets()}.
+costs_map_roots(DSets0, Costs) ->
+ {Entry1, DSets1} = costs_map_roots_1(DSets0, Costs#costs.entry1),
+ {Entry2, DSets2} = costs_map_roots_1(DSets1, Costs#costs.entry2),
+ {Exit, DSets3} = costs_map_roots_1(DSets2, Costs#costs.exit),
+ {Spill, DSets4} = costs_map_roots_1(DSets3, Costs#costs.spill),
+ {Restore, DSets} = costs_map_roots_1(DSets4, Costs#costs.restore),
+ {#costs{entry1=Entry1,entry2=Entry2,exit=Exit,spill=Spill,restore=Restore},
+ DSets}.
+
+costs_map_roots_1(DSets0, CostMap) ->
+ {NewEs, DSets} = lists:mapfoldl(fun({[A|T], Wt}, DSets1) ->
+ {AR, DSets2} = hipe_dsets:find(A, DSets1),
+ {{[AR|T], Wt}, DSets2}
+ end, DSets0, maps:to_list(CostMap)),
+ {maps_from_list_merge(NewEs, fun erlang:'+'/2, #{}), DSets}.
+
+maps_from_list_merge([], _MF, Acc) -> Acc;
+maps_from_list_merge([{K,V}|Ps], MF, Acc) ->
+ maps_from_list_merge(Ps, MF, case Acc of
+ #{K := OV} -> Acc#{K := MF(V, OV)};
+ #{} -> Acc#{K => V}
+ end).
+
+-spec costs_query(temp(), cost_key(), part_key(), costs()) -> float().
+costs_query(Temp, entry1, Part, #costs{entry1=Entry1}) ->
+ costs_query_1(Temp, Part, Entry1);
+costs_query(Temp, entry2, Part, #costs{entry2=Entry2}) ->
+ costs_query_1(Temp, Part, Entry2);
+costs_query(Temp, exit, Part, #costs{exit=Exit}) ->
+ costs_query_1(Temp, Part, Exit);
+costs_query(Temp, spill, Part, #costs{spill=Spill}) ->
+ costs_query_1(Temp, Part, Spill);
+costs_query(Temp, restore, Part, #costs{restore=Restore}) ->
+ costs_query_1(Temp, Part, Restore).
+
+costs_query_1(Temp, Part, CostMap) ->
+ Key = [Part|Temp],
+ case CostMap of
+ #{Key := Wt} -> Wt;
+ #{} -> 0.0
+ end.
+
+-spec map_update_counter(Key, number(), #{Key => number(), OK => OV})
+ -> #{Key := number(), OK => OV}.
+map_update_counter(Key, Incr, Map) ->
+ case Map of
+ #{Key := Orig} -> Map#{Key := Orig + Incr};
+ #{} -> Map#{Key => Incr}
+ end.
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Def and use counting ADT
+-type ducount() :: #{temp() => float()}.
+
+-spec ducount_new() -> ducount().
+ducount_new() -> #{}.
+
+-spec ducount_add([temp()], float(), ducount()) -> ducount().
+ducount_add([], _Weight, DUCount) -> DUCount;
+ducount_add([T|Ts], Weight, DUCount0) ->
+ DUCount =
+ case DUCount0 of
+ #{T := Count} -> DUCount0#{T := Count + Weight};
+ #{} -> DUCount0#{T => Weight}
+ end,
+ ducount_add(Ts, Weight, DUCount).
+
+ducount_to_list(DUCount) -> maps:to_list(DUCount).
+
+-spec ducount_merge(ducount(), ducount()) -> ducount().
+ducount_merge(DCA, DCB) when map_size(DCA) < map_size(DCB) ->
+ ducount_merge_1(ducount_to_list(DCA), DCB);
+ducount_merge(DCA, DCB) when map_size(DCA) >= map_size(DCB) ->
+ ducount_merge_1(ducount_to_list(DCB), DCA).
+
+ducount_merge_1([], DUCount) -> DUCount;
+ducount_merge_1([{T,AC}|Ts], DUCount0) ->
+ DUCount =
+ case DUCount0 of
+ #{T := BC} -> DUCount0#{T := AC + BC};
+ #{} -> DUCount0#{T => AC}
+ end,
+ ducount_merge_1(Ts, DUCount).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Target module interface functions
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+-define(TGT_IFACE_0(N), N( {M,C}) -> M:N( C)).
+-define(TGT_IFACE_1(N), N(A1, {M,C}) -> M:N(A1, C)).
+-define(TGT_IFACE_2(N), N(A1,A2, {M,C}) -> M:N(A1,A2, C)).
+-define(TGT_IFACE_3(N), N(A1,A2,A3,{M,C}) -> M:N(A1,A2,A3,C)).
+
+?TGT_IFACE_2(bb).
+?TGT_IFACE_1(def_use).
+?TGT_IFACE_1(defines).
+?TGT_IFACE_1(defines_all_alloc).
+?TGT_IFACE_1(is_precoloured).
+?TGT_IFACE_1(mk_goto).
+?TGT_IFACE_2(mk_move).
+?TGT_IFACE_0(new_label).
+?TGT_IFACE_0(new_reg_nr).
+?TGT_IFACE_1(number_of_temporaries).
+?TGT_IFACE_3(redirect_jmp).
+?TGT_IFACE_1(reg_nr).
+?TGT_IFACE_1(reverse_postorder).
+?TGT_IFACE_2(subst_temps).
+?TGT_IFACE_3(update_bb).
+?TGT_IFACE_2(update_reg_nr).
+
+branch_preds(Instr, {TgtMod,TgtCtx}) ->
+ merge_sorted_preds(lists:keysort(1, TgtMod:branch_preds(Instr, TgtCtx))).
+
+livein(Liveness, L, Target={TgtMod,TgtCtx}) ->
+ ordsets:from_list(reg_names(TgtMod:livein(Liveness, L, TgtCtx), Target)).
+
+liveout(Liveness, L, Target={TgtMod,TgtCtx}) ->
+ ordsets:from_list(reg_names(TgtMod:liveout(Liveness, L, TgtCtx), Target)).
+
+merge_sorted_preds([]) -> [];
+merge_sorted_preds([{L, P1}, {L, P2}|LPs]) ->
+ merge_sorted_preds([{L, P1+P2}|LPs]);
+merge_sorted_preds([LP|LPs]) -> [LP|merge_sorted_preds(LPs)].
+
+reg_names(Regs, {TgtMod,TgtCtx}) ->
+ [TgtMod:reg_nr(X,TgtCtx) || X <- Regs].