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authorBjörn Gustavsson <bjorn@erlang.org>2015-02-20 10:17:43 +0100
committerBjörn Gustavsson <bjorn@erlang.org>2015-02-20 10:17:43 +0100
commit67c60f481e6b38419774c227eed3e50a57680b58 (patch)
treebf345246248ff319ec132bac513fed035dacf30f /lib
parent5c0d4346409161838dabeae2366cb7f4ee95fbc0 (diff)
parentf342b0322f0c594f18e9b5dffd0c5c751804b47f (diff)
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Merge branch 'bjorn/compiler/beam_jump'
* bjorn/compiler/beam_jump: beam_jump: Eliminate pathologically slow compilation
Diffstat (limited to 'lib')
-rw-r--r--lib/compiler/src/beam_jump.erl34
1 files changed, 25 insertions, 9 deletions
diff --git a/lib/compiler/src/beam_jump.erl b/lib/compiler/src/beam_jump.erl
index 4e699c4fbf..52fe0e90ce 100644
--- a/lib/compiler/src/beam_jump.erl
+++ b/lib/compiler/src/beam_jump.erl
@@ -295,12 +295,6 @@ 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 +304,20 @@ 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 +354,17 @@ 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.