diff options
Diffstat (limited to 'lib/compiler/src/beam_z.erl')
| -rw-r--r-- | lib/compiler/src/beam_z.erl | 30 |
1 files changed, 25 insertions, 5 deletions
diff --git a/lib/compiler/src/beam_z.erl b/lib/compiler/src/beam_z.erl index 1c56b95a9e..6c3a6995d7 100644 --- a/lib/compiler/src/beam_z.erl +++ b/lib/compiler/src/beam_z.erl @@ -24,18 +24,20 @@ -export([module/2]). --import(lists, [dropwhile/2]). +-import(lists, [dropwhile/2,map/2]). -spec module(beam_utils:module_code(), [compile:option()]) -> {'ok',beam_asm:module_code()}. -module({Mod,Exp,Attr,Fs0,Lc}, _Opt) -> - Fs = [function(F) || F <- Fs0], +module({Mod,Exp,Attr,Fs0,Lc}, Opts) -> + NoGetHdTl = proplists:get_bool(no_get_hd_tl, Opts), + Fs = [function(F, NoGetHdTl) || F <- Fs0], {ok,{Mod,Exp,Attr,Fs,Lc}}. -function({function,Name,Arity,CLabel,Is0}) -> +function({function,Name,Arity,CLabel,Is0}, NoGetHdTl) -> try - Is = undo_renames(Is0), + Is1 = undo_renames(Is0), + Is = maybe_eliminate_get_hd_tl(Is1, NoGetHdTl), {function,Name,Arity,CLabel,Is} catch Class:Error:Stack -> @@ -65,6 +67,10 @@ undo_renames([{bif,raise,_,_,_}=I|Is0]) -> (_) -> true end, Is0), [I|undo_renames(Is)]; +undo_renames([{get_hd,Src,Dst1},{get_tl,Src,Dst2}|Is]) -> + [{get_list,Src,Dst1,Dst2}|undo_renames(Is)]; +undo_renames([{get_tl,Src,Dst2},{get_hd,Src,Dst1}|Is]) -> + [{get_list,Src,Dst1,Dst2}|undo_renames(Is)]; undo_renames([I|Is]) -> [undo_rename(I)|undo_renames(Is)]; undo_renames([]) -> []. @@ -107,3 +113,17 @@ undo_rename({get_map_elements,Fail,Src,{list,List}}) -> undo_rename({select,I,Reg,Fail,List}) -> {I,Reg,Fail,{list,List}}; undo_rename(I) -> I. + +%%% +%%% Eliminate get_hd/get_tl instructions if requested by +%%% the no_get_hd_tl option. +%%% + +maybe_eliminate_get_hd_tl(Is, true) -> + map(fun({get_hd,Cons,Hd}) -> + {get_list,Cons,Hd,{x,1022}}; + ({get_tl,Cons,Tl}) -> + {get_list,Cons,{x,1022},Tl}; + (I) -> I + end, Is); +maybe_eliminate_get_hd_tl(Is, false) -> Is. |