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authorBjörn Gustavsson <[email protected]>2016-05-24 16:56:10 +0200
committerBjörn Gustavsson <[email protected]>2016-05-25 16:41:26 +0200
commitc0a93fe2b9e36e00e9e3ebdec7840889ac571f6a (patch)
treebeeb6e295390ad326fc0dff89f9905c0c6722b36 /lib/compiler/src
parent27ec25fee753da60d36ce560ce34b9cef7dc8df7 (diff)
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beam_jump: Clean up handling of labels before func_info
In complicated code with many indirect jumps to the func_info label, a label could get lost.
Diffstat (limited to 'lib/compiler/src')
-rw-r--r--lib/compiler/src/beam_jump.erl50
1 files changed, 24 insertions, 26 deletions
diff --git a/lib/compiler/src/beam_jump.erl b/lib/compiler/src/beam_jump.erl
index 359248c6af..09cd3aa2d4 100644
--- a/lib/compiler/src/beam_jump.erl
+++ b/lib/compiler/src/beam_jump.erl
@@ -266,17 +266,17 @@ extract_seq_1(_, _) -> no.
%%% (3) (4) (5) (6) Jump and unreachable code optimizations.
%%%
--record(st, {fc, %Label for function class errors.
- entry, %Entry label (must not be moved).
- mlbl, %Moved labels.
- labels :: cerl_sets:set() %Set of referenced labels.
- }).
-
-opt([{label,Fc}|_]=Is0, CLabel) ->
- Lbls = initial_labels(Is0),
+-record(st,
+ {
+ entry, %Entry label (must not be moved).
+ mlbl, %Moved labels.
+ labels :: cerl_sets:set() %Set of referenced labels.
+ }).
+
+opt(Is0, CLabel) ->
find_fixpoint(fun(Is) ->
- St = #st{fc=Fc,entry=CLabel,mlbl=#{},
- labels=Lbls},
+ Lbls = initial_labels(Is),
+ St = #st{entry=CLabel,mlbl=#{},labels=Lbls},
opt(Is, [], St)
end, Is0).
@@ -327,7 +327,8 @@ opt([{label,Lbl}=I|Is], Acc, #st{mlbl=Mlbl}=St0) ->
%% since we will rescan the inserted labels. We MUST rescan.
St = St0#st{mlbl=maps:remove(Lbl, Mlbl)},
insert_labels([Lbl|Lbls], Is, Acc, St);
- error -> opt(Is, [I|Acc], St0)
+ error ->
+ opt(Is, [I|Acc], St0)
end;
opt([{jump,{f,_}=X}|[{label,_},{jump,X}|_]=Is], Acc, St) ->
opt(Is, Acc, St);
@@ -362,12 +363,19 @@ opt([I|Is], Acc, #st{labels=Used0}=St0) ->
true -> skip_unreachable(Is, [I|Acc], St);
false -> opt(Is, [I|Acc], St)
end;
-opt([], Acc, #st{fc=Fc,mlbl=Mlbl}) ->
+opt([], Acc, #st{mlbl=Mlbl}) ->
Code = reverse(Acc),
- case maps:find(Fc, Mlbl) of
- {ok,Lbls} -> insert_fc_labels(Lbls, Mlbl, Code);
- error -> Code
- end.
+ insert_fc_labels(Code, Mlbl).
+
+insert_fc_labels([{label,L}=I|Is0], Mlbl) ->
+ case maps:find(L, Mlbl) of
+ error ->
+ [I|insert_fc_labels(Is0, Mlbl)];
+ {ok,Lbls} ->
+ Is = [{label,Lb} || Lb <- Lbls] ++ Is0,
+ [I|insert_fc_labels(Is, maps:remove(L, Mlbl))]
+ end;
+insert_fc_labels([_|_]=Is, _) -> Is.
maps_append_list(K,Vs,M) ->
case M of
@@ -375,16 +383,6 @@ maps_append_list(K,Vs,M) ->
_ -> M#{K => Vs}
end.
-insert_fc_labels([L|Ls], Mlbl, Acc0) ->
- Acc = [{label,L}|Acc0],
- case maps:find(L, Mlbl) of
- error ->
- insert_fc_labels(Ls, Mlbl, Acc);
- {ok,Lbls} ->
- insert_fc_labels(Lbls++Ls, Mlbl, Acc)
- end;
-insert_fc_labels([], _, Acc) -> Acc.
-
collect_labels(Is, #st{entry=Entry}) ->
collect_labels_1(Is, Entry, []).