diff options
Diffstat (limited to 'lib/compiler/src/beam_bs.erl')
| -rw-r--r-- | lib/compiler/src/beam_bs.erl | 141 |
1 files changed, 22 insertions, 119 deletions
diff --git a/lib/compiler/src/beam_bs.erl b/lib/compiler/src/beam_bs.erl index 5f1b9ed488..15d8d687fc 100644 --- a/lib/compiler/src/beam_bs.erl +++ b/lib/compiler/src/beam_bs.erl @@ -17,26 +17,24 @@ %% %% %CopyrightEnd% %% -%% Purpose : Partitions assembly instructions into basic blocks and -%% optimizes them. +%% Purpose: Peephole optimization of binary syntax instructions. -module(beam_bs). -export([module/2]). --import(lists, [mapfoldl/3,reverse/1]). +-import(lists, [reverse/1]). -spec module(beam_utils:module_code(), [compile:option()]) -> {'ok',beam_utils:module_code()}. -module({Mod,Exp,Attr,Fs0,Lc0}, _Opt) -> - {Fs,Lc} = mapfoldl(fun function/2, Lc0, Fs0), +module({Mod,Exp,Attr,Fs0,Lc}, _Opt) -> + Fs = [function(F) || F <- Fs0], {ok,{Mod,Exp,Attr,Fs,Lc}}. -function({function,Name,Arity,CLabel,Is0}, Lc0) -> +function({function,Name,Arity,CLabel,Is0}) -> try - Is1 = bs_put_opt(Is0), - {Is,Lc} = bsm_opt(Is1, Lc0), - {{function,Name,Arity,CLabel,Is},Lc} + Is = bs_opt(Is0), + {function,Name,Arity,CLabel,Is} catch Class:Error:Stack -> io:fwrite("Function: ~w/~w\n", [Name,Arity]), @@ -44,16 +42,25 @@ function({function,Name,Arity,CLabel,Is0}, Lc0) -> end. %%% -%%% Evaluation of constant bit fields. +%%% Evaluate construction of constant bit fields. +%%% Combine bs_skip_bits2 and bs_test_tail2 instructions. %%% -bs_put_opt([{bs_put,_,_,_}=I|Is0]) -> +bs_opt([{bs_put,_,_,_}=I|Is0]) -> {BsPuts0,Is} = collect_bs_puts(Is0, [I]), BsPuts = opt_bs_puts(BsPuts0), - BsPuts ++ bs_put_opt(Is); -bs_put_opt([I|Is]) -> - [I|bs_put_opt(Is)]; -bs_put_opt([]) -> []. + BsPuts ++ bs_opt(Is); +bs_opt([{test,bs_skip_bits2,F,[Ctx,{integer,I},Unit,_Flags]}, + {test,bs_test_tail2,F,[Ctx,Bits]}|Is]) -> + [{test,bs_test_tail2,F,[Ctx,Bits+I*Unit]}|bs_opt(Is)]; +bs_opt([{test,bs_skip_bits2,F,[Ctx,{integer,I1},Unit1,Flags]}, + {test,bs_skip_bits2,F,[Ctx,{integer,I2},Unit2,_]}|Is]) -> + I = {test,bs_skip_bits2,F, + [Ctx,{integer,I1*Unit1+I2*Unit2},1,Flags]}, + bs_opt([I|Is]); +bs_opt([I|Is]) -> + [I|bs_opt(Is)]; +bs_opt([]) -> []. collect_bs_puts([{bs_put,_,_,_}=I|Is], Acc) -> collect_bs_puts(Is, [I|Acc]); @@ -174,107 +181,3 @@ bs_split_int_1(N, ByteSz, Sz, Fail, Acc) when Sz > 0 -> [{integer,ByteSz},{integer,N band Mask}]}, bs_split_int_1(N bsr ByteSz, 8, Sz-ByteSz, Fail, [I|Acc]); bs_split_int_1(_, _, _, _, Acc) -> Acc. - -%%% -%%% Optimization of bit syntax matching: get rid -%%% of redundant bs_restore2/2 instructions across select_val -%%% instructions, as well as a few other simple peep-hole -%%% optimizations. -%%% - -bsm_opt(Is0, Lc0) -> - {Is1,D0,Lc} = bsm_scan(Is0, [], Lc0, []), - Is2 = case D0 of - [] -> - %% No bit syntax matching in this function. - Is1; - [_|_] -> - %% Optimize the bit syntax matching. - D = gb_trees:from_orddict(orddict:from_list(D0)), - bsm_reroute(Is1, D, none, []) - end, - Is = beam_clean:bs_clean_saves(Is2), - {bsm_opt_2(Is, []),Lc}. - -bsm_scan([{label,L}=Lbl,{bs_restore2,_,Save}=R|Is], D0, Lc, Acc0) -> - D = [{{L,Save},Lc}|D0], - Acc = [{label,Lc},R,Lbl|Acc0], - bsm_scan(Is, D, Lc+1, Acc); -bsm_scan([I|Is], D, Lc, Acc) -> - bsm_scan(Is, D, Lc, [I|Acc]); -bsm_scan([], D, Lc, Acc) -> - {reverse(Acc),D,Lc}. - -bsm_reroute([{bs_save2,Reg,Save}=I|Is], D, _, Acc) -> - bsm_reroute(Is, D, {Reg,Save}, [I|Acc]); -bsm_reroute([{bs_restore2,Reg,Save}=I|Is], D, _, Acc) -> - bsm_reroute(Is, D, {Reg,Save}, [I|Acc]); -bsm_reroute([{label,_}=I|Is], D, S, Acc) -> - bsm_reroute(Is, D, S, [I|Acc]); -bsm_reroute([{select,select_val,Reg,F0,Lbls0}|Is], D, {_,Save}=S, Acc0) -> - [F|Lbls] = bsm_subst_labels([F0|Lbls0], Save, D), - Acc = [{select,select_val,Reg,F,Lbls}|Acc0], - bsm_reroute(Is, D, S, Acc); -bsm_reroute([{test,TestOp,F0,TestArgs}=I|Is], D, {_,Save}=S, Acc0) -> - F = bsm_subst_label(F0, Save, D), - Acc = [{test,TestOp,F,TestArgs}|Acc0], - case bsm_not_bs_test(I) of - true -> - %% The test instruction will not update the bit offset for - %% the binary being matched. Therefore the save position - %% can be kept. - bsm_reroute(Is, D, S, Acc); - false -> - %% The test instruction might update the bit offset. Kill - %% our remembered Save position. - bsm_reroute(Is, D, none, Acc) - end; -bsm_reroute([{test,TestOp,F0,Live,TestArgs,Dst}|Is], D, {_,Save}, Acc0) -> - F = bsm_subst_label(F0, Save, D), - Acc = [{test,TestOp,F,Live,TestArgs,Dst}|Acc0], - %% The test instruction will update the bit offset. Kill our - %% remembered Save position. - bsm_reroute(Is, D, none, Acc); -bsm_reroute([{block,[{set,[],[],{alloc,_,_}}]}=Bl, - {bs_context_to_binary,_}=I|Is], D, S, Acc) -> - %% To help further bit syntax optimizations. - bsm_reroute([I,Bl|Is], D, S, Acc); -bsm_reroute([I|Is], D, _, Acc) -> - bsm_reroute(Is, D, none, [I|Acc]); -bsm_reroute([], _, _, Acc) -> reverse(Acc). - -bsm_opt_2([{test,bs_test_tail2,F,[Ctx,Bits]}|Is], - [{test,bs_skip_bits2,F,[Ctx,{integer,I},Unit,_Flags]}|Acc]) -> - bsm_opt_2(Is, [{test,bs_test_tail2,F,[Ctx,Bits+I*Unit]}|Acc]); -bsm_opt_2([{test,bs_skip_bits2,F,[Ctx,{integer,I1},Unit1,_]}|Is], - [{test,bs_skip_bits2,F,[Ctx,{integer,I2},Unit2,Flags]}|Acc]) -> - bsm_opt_2(Is, [{test,bs_skip_bits2,F, - [Ctx,{integer,I1*Unit1+I2*Unit2},1,Flags]}|Acc]); -bsm_opt_2([I|Is], Acc) -> - bsm_opt_2(Is, [I|Acc]); -bsm_opt_2([], Acc) -> reverse(Acc). - -%% bsm_not_bs_test({test,Name,_,Operands}) -> true|false. -%% Test whether is the test is a "safe", i.e. does not move the -%% bit offset for a binary. -%% -%% 'true' means that the test is safe, 'false' that we don't know or -%% that the test moves the offset (e.g. bs_get_integer2). - -bsm_not_bs_test({test,bs_test_tail2,_,[_,_]}) -> true; -bsm_not_bs_test(Test) -> beam_utils:is_pure_test(Test). - -bsm_subst_labels(Fs, Save, D) -> - bsm_subst_labels_1(Fs, Save, D, []). - -bsm_subst_labels_1([F|Fs], Save, D, Acc) -> - bsm_subst_labels_1(Fs, Save, D, [bsm_subst_label(F, Save, D)|Acc]); -bsm_subst_labels_1([], _, _, Acc) -> - reverse(Acc). - -bsm_subst_label({f,Lbl0}=F, Save, D) -> - case gb_trees:lookup({Lbl0,Save}, D) of - {value,Lbl} -> {f,Lbl}; - none -> F - end; -bsm_subst_label(Other, _, _) -> Other. |