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-rw-r--r--lib/compiler/src/beam_validator.erl37
1 files changed, 36 insertions, 1 deletions
diff --git a/lib/compiler/src/beam_validator.erl b/lib/compiler/src/beam_validator.erl
index f8bf935132..c30ab34ac7 100644
--- a/lib/compiler/src/beam_validator.erl
+++ b/lib/compiler/src/beam_validator.erl
@@ -591,6 +591,12 @@ valfun_4({get_list,Src,D1,D2}, Vst0) ->
assert_type(cons, Src, Vst0),
Vst = set_type_reg(term, D1, Vst0),
set_type_reg(term, D2, Vst);
+valfun_4({get_hd,Src,Dst}, Vst) ->
+ assert_type(cons, Src, Vst),
+ set_type_reg(term, Dst, Vst);
+valfun_4({get_tl,Src,Dst}, Vst) ->
+ assert_type(cons, Src, Vst),
+ set_type_reg(term, Dst, Vst);
valfun_4({get_tuple_element,Src,I,Dst}, Vst) ->
assert_type({tuple_element,I+1}, Src, Vst),
set_type_reg(term, Dst, Vst);
@@ -1147,6 +1153,7 @@ set_type_y(Type, {y,Y}=Reg, #vst{current=#st{y=Ys0}=St}=Vst)
{value,_} ->
gb_trees:update(Y, Type, Ys0)
end,
+ check_try_catch_tags(Type, Y, Ys0),
Vst#vst{current=St#st{y=Ys}};
set_type_y(Type, Reg, #vst{}) -> error({invalid_store,Reg,Type}).
@@ -1154,6 +1161,29 @@ set_catch_end({y,Y}, #vst{current=#st{y=Ys0}=St}=Vst) ->
Ys = gb_trees:update(Y, initialized, Ys0),
Vst#vst{current=St#st{y=Ys}}.
+check_try_catch_tags(Type, LastY, Ys) ->
+ case is_try_catch_tag(Type) of
+ false ->
+ ok;
+ true ->
+ %% Every catch or try/catch must use a lower Y register
+ %% number than any enclosing catch or try/catch. That will
+ %% ensure that when the stack is scanned when an
+ %% exception occurs, the innermost try/catch tag is found
+ %% first.
+ Bad = [{{y,Y},Tag} || {Y,Tag} <- gb_trees:to_list(Ys),
+ Y < LastY, is_try_catch_tag(Tag)],
+ case Bad of
+ [] ->
+ ok;
+ [_|_] ->
+ error({bad_try_catch_nesting,{y,LastY},Bad})
+ end
+ end.
+
+is_try_catch_tag({catchtag,_}) -> true;
+is_try_catch_tag({trytag,_}) -> true;
+is_try_catch_tag(_) -> false.
is_reg_defined({x,_}=Reg, Vst) -> is_type_defined_x(Reg, Vst);
is_reg_defined({y,_}=Reg, Vst) -> is_type_defined_y(Reg, Vst);
@@ -1343,7 +1373,12 @@ branch_arities([Sz,{f,L}|T], Tuple, #vst{current=St}=Vst0)
Vst = branch_state(L, Vst1),
branch_arities(T, Tuple, Vst#vst{current=St}).
-branch_state(0, #vst{}=Vst) -> Vst;
+branch_state(0, #vst{}=Vst) ->
+ %% If the instruction fails, the stack may be scanned
+ %% looking for a catch tag. Therefore the Y registers
+ %% must be initialized at this point.
+ verify_y_init(Vst),
+ Vst;
branch_state(L, #vst{current=St,branched=B}=Vst) ->
Vst#vst{
branched=case gb_trees:is_defined(L, B) of