diff options
Diffstat (limited to 'lib/compiler/src/beam_jump.erl')
| -rw-r--r-- | lib/compiler/src/beam_jump.erl | 69 |
1 files changed, 55 insertions, 14 deletions
diff --git a/lib/compiler/src/beam_jump.erl b/lib/compiler/src/beam_jump.erl index 4e699c4fbf..52b6464c7f 100644 --- a/lib/compiler/src/beam_jump.erl +++ b/lib/compiler/src/beam_jump.erl @@ -127,7 +127,7 @@ %%% on the program state. %%% --import(lists, [reverse/1,reverse/2,foldl/3,dropwhile/2]). +-import(lists, [reverse/1,reverse/2,foldl/3]). module({Mod,Exp,Attr,Fs0,Lc}, _Opt) -> Fs = [function(F) || F <- Fs0], @@ -166,6 +166,12 @@ share_1([{label,L}=Lbl|Is], Dict0, Seq, Acc) -> end; share_1([{func_info,_,_,_}=I|Is], _, [], Acc) -> reverse(Is, [I|Acc]); +share_1([{'try',_,_}=I|Is], Dict0, Seq, Acc) -> + Dict = clean_non_sharable(Dict0), + share_1(Is, Dict, [I|Seq], Acc); +share_1([{try_case,_}=I|Is], Dict0, Seq, Acc) -> + Dict = clean_non_sharable(Dict0), + share_1(Is, Dict, [I|Seq], Acc); share_1([I|Is], Dict, Seq, Acc) -> case is_unreachable_after(I) of false -> @@ -174,6 +180,24 @@ share_1([I|Is], Dict, Seq, Acc) -> share_1(Is, Dict, [I], Acc) end. +clean_non_sharable(Dict) -> + %% We are passing in or out of a 'try' block. Remove + %% sequences that should not shared over the boundaries + %% of a 'try' block. Since the end of the sequence must match, + %% the only possible match between a sequence outside and + %% a sequence inside the 'try' block is a sequence that ends + %% with an instruction that causes an exception. Any sequence + %% that causes an exception must contain a line/1 instruction. + dict:filter(fun(K, _V) -> sharable_with_try(K) end, Dict). + +sharable_with_try([{line,_}|_]) -> + %% This sequence may cause an exception and may potentially + %% match a sequence on the other side of the 'try' block + %% boundary. + false; +sharable_with_try([_|Is]) -> + sharable_with_try(Is); +sharable_with_try([]) -> true. %% Eliminate all fallthroughs. Return the result reversed. @@ -295,12 +319,6 @@ opt([{test,_,{f,_}=Lbl,_,_,_}=I|Is], Acc, St) -> opt(Is, [I|Acc], label_used(Lbl, St)); opt([{select,_,_R,Fail,Vls}=I|Is], Acc, St) -> skip_unreachable(Is, [I|Acc], label_used([Fail|Vls], St)); -opt([{label,L}=I|Is], Acc, #st{entry=L}=St) -> - %% NEVER move the entry label. - opt(Is, [I|Acc], St); -opt([{label,L1},{jump,{f,L2}}=I|Is], [Prev|Acc], St0) -> - St = St0#st{mlbl=dict:append(L2, L1, St0#st.mlbl)}, - opt([Prev,I|Is], Acc, label_used({f,L2}, St)); opt([{label,Lbl}=I|Is], Acc, #st{mlbl=Mlbl}=St0) -> case dict:find(Lbl, Mlbl) of {ok,Lbls} -> @@ -310,9 +328,20 @@ opt([{label,Lbl}=I|Is], Acc, #st{mlbl=Mlbl}=St0) -> insert_labels([Lbl|Lbls], Is, Acc, St); error -> opt(Is, [I|Acc], St0) end; -opt([{jump,{f,Lbl}},{label,Lbl}=I|Is], Acc, St) -> - opt([I|Is], Acc, St); -opt([{jump,Lbl}=I|Is], Acc, St) -> +opt([{jump,{f,_}=X}|[{label,_},{jump,X}|_]=Is], Acc, St) -> + opt(Is, Acc, St); +opt([{jump,{f,Lbl}}|[{label,Lbl}|_]=Is], Acc, St) -> + opt(Is, Acc, St); +opt([{jump,{f,L}=Lbl}=I|Is], Acc0, #st{mlbl=Mlbl0}=St0) -> + %% All labels before this jump instruction should now be + %% moved to the location of the jump's target. + {Lbls,Acc} = collect_labels(Acc0, St0), + St = case Lbls of + [] -> St0; + [_|_] -> + Mlbl = dict:append_list(L, Lbls, Mlbl0), + St0#st{mlbl=Mlbl} + end, skip_unreachable(Is, [I|Acc], label_used(Lbl, St)); %% Optimization: quickly handle some common instructions that don't %% have any failure labels and where is_unreachable_after(I) =:= false. @@ -349,6 +378,17 @@ insert_fc_labels([L|Ls], Mlbl, Acc0) -> end; insert_fc_labels([], _, Acc) -> Acc. +collect_labels(Is, #st{entry=Entry}) -> + collect_labels_1(Is, Entry, []). + +collect_labels_1([{label,Entry}|_]=Is, Entry, Acc) -> + %% Never move the entry label. + {Acc,Is}; +collect_labels_1([{label,L}|Is], Entry, Acc) -> + collect_labels_1(Is, Entry, [L|Acc]); +collect_labels_1(Is, _Entry, Acc) -> + {Acc,Is}. + %% label_defined(Is, Label) -> true | false. %% Test whether the label Label is defined at the start of the instruction %% sequence, possibly preceeded by other label definitions. @@ -469,10 +509,7 @@ rem_unused([{label,Lbl}=I|Is0], Used, [Prev|_]=Acc) -> case gb_sets:is_member(Lbl, Used) of false -> Is = case is_unreachable_after(Prev) of - true -> - dropwhile(fun({label,_}) -> false; - (_) -> true - end, Is0); + true -> drop_upto_label(Is0); false -> Is0 end, rem_unused(Is, Used, Acc); @@ -493,6 +530,10 @@ initial_labels([{label,Lbl}|Is], Acc) -> initial_labels([{func_info,_,_,_},{label,Lbl}|_], Acc) -> gb_sets:from_list([Lbl|Acc]). +drop_upto_label([{label,_}|_]=Is) -> Is; +drop_upto_label([_|Is]) -> drop_upto_label(Is); +drop_upto_label([]) -> []. + %% ulbl(Instruction, UsedGbSet) -> UsedGbSet' %% Update the gb_set UsedGbSet with any function-local labels %% (i.e. not with labels in call instructions) referenced by |