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| author | Björn Gustavsson <[email protected]> | 2015-04-18 07:24:53 +0200 |
|---|---|---|
| committer | Björn Gustavsson <[email protected]> | 2015-04-22 10:14:55 +0200 |
| commit | 93ad33ddcdceb201239f9c5133f2c51769006a2a (patch) | |
| tree | 707442888215b475b61bdb69cb93b53f72679f3e | |
| parent | de9c0ab5295fb0a16b05c4df101074ce9cd6695b (diff) | |
| download | otp-93ad33ddcdceb201239f9c5133f2c51769006a2a.tar.gz otp-93ad33ddcdceb201239f9c5133f2c51769006a2a.tar.bz2 otp-93ad33ddcdceb201239f9c5133f2c51769006a2a.zip | |
beam_bsm: Optimize btb_index()
lists:dropwhile/2 and the fun in btb_index_1/2 shows up in the
top 10 list of eprof. Replace dropwhile with a special-purpose
function for a tiny increase in speed.
| -rw-r--r-- | lib/compiler/src/beam_bsm.erl | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/lib/compiler/src/beam_bsm.erl b/lib/compiler/src/beam_bsm.erl index d54c2a9fde..427b7071ac 100644 --- a/lib/compiler/src/beam_bsm.erl +++ b/lib/compiler/src/beam_bsm.erl @@ -20,7 +20,7 @@ -module(beam_bsm). -export([module/2,format_error/1]). --import(lists, [member/2,foldl/3,reverse/1,sort/1,all/2,dropwhile/2]). +-import(lists, [member/2,foldl/3,reverse/1,sort/1,all/2]). %%% %%% We optimize bit syntax matching where the tail end of a binary is @@ -542,16 +542,13 @@ btb_context_regs_1(Regs, N, Tag, Acc) -> %% a binary. MustSave is true if the function may pass the match %% context to the bs_context_to_binary instruction (in which case %% the current position in the binary must have saved into the -%% start position using "bs_save_2 Ctx start". +%% start position using "bs_save_2 Ctx start"). btb_index(Fs) -> btb_index_1(Fs, []). btb_index_1([{function,_,_,Entry,Is0}|Fs], Acc0) -> - [{label,Entry}|Is] = - dropwhile(fun({label,L}) when L =:= Entry -> false; - (_) -> true - end, Is0), + Is = drop_to_label(Is0, Entry), Acc = btb_index_2(Is, Entry, false, Acc0), btb_index_1(Fs, Acc); btb_index_1([], Acc) -> gb_trees:from_orddict(sort(Acc)). @@ -566,6 +563,9 @@ btb_index_2(Is0, Entry, _, Acc) -> throw:none -> Acc end. +drop_to_label([{label,L}|Is], L) -> Is; +drop_to_label([_|Is], L) -> drop_to_label(Is, L). + btb_index_find_start_match([{test,_,{f,F},_},{bs_context_to_binary,_}|Is]) -> btb_index_find_label(Is, F); btb_index_find_start_match(_) -> |