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authorBjörn Gustavsson <[email protected]>2018-03-07 06:08:43 +0100
committerBjörn Gustavsson <[email protected]>2018-08-17 09:50:58 +0200
commit22f0a7f6356bf798eaff13402426b99ce8457b3c (patch)
tree7c2f8300f0517bb63edc3508a41e30b15433f119 /lib/compiler/src
parentec2f6ef0d5170220d39ad3a8e763fe2e5b9b7bb7 (diff)
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beam_validator: Be more careful when updating try/catch state
The new code generator will more aggressively reuse registers, so we must be more careful about updating the state for try/catch. In particular, an "empty" try/catch that can't throw an exception must not update the try/catch state.
Diffstat (limited to 'lib/compiler/src')
-rw-r--r--lib/compiler/src/beam_validator.erl58
1 files changed, 30 insertions, 28 deletions
diff --git a/lib/compiler/src/beam_validator.erl b/lib/compiler/src/beam_validator.erl
index c09dbadd7f..c85e8f53ac 100644
--- a/lib/compiler/src/beam_validator.erl
+++ b/lib/compiler/src/beam_validator.erl
@@ -27,7 +27,7 @@
%% Interface for compiler.
-export([module/2, format_error/1]).
--import(lists, [any/2,dropwhile/2,foldl/3,foreach/2,reverse/1]).
+-import(lists, [any/2,dropwhile/2,foldl/3,map/2,foreach/2,reverse/1]).
%% To be called by the compiler.
@@ -413,30 +413,22 @@ valfun_1({trim,N,Remaining}, #vst{current=#st{y=Yregs0,numy=NumY}=St}=Vst) ->
error({trim,N,Remaining,allocated,NumY})
end;
%% Catch & try.
-valfun_1({'catch',Dst,{f,Fail}}, Vst0) when Fail /= none ->
- Vst = #vst{current=#st{ct=Fails}=St} =
- set_type_y({catchtag,[Fail]}, Dst, Vst0),
- Vst#vst{current=St#st{ct=[[Fail]|Fails]}};
-valfun_1({'try',Dst,{f,Fail}}, Vst0) ->
- Vst = #vst{current=#st{ct=Fails}=St} =
- set_type_y({trytag,[Fail]}, Dst, Vst0),
- Vst#vst{current=St#st{ct=[[Fail]|Fails]}};
+valfun_1({'catch',Dst,{f,Fail}}, Vst) when Fail =/= none ->
+ init_try_catch_branch(catchtag, Dst, Fail, Vst);
+valfun_1({'try',Dst,{f,Fail}}, Vst) when Fail =/= none ->
+ init_try_catch_branch(trytag, Dst, Fail, Vst);
valfun_1({catch_end,Reg}, #vst{current=#st{ct=[Fail|Fails]}}=Vst0) ->
case get_special_y_type(Reg, Vst0) of
{catchtag,Fail} ->
Vst = #vst{current=St} = set_catch_end(Reg, Vst0),
- Xs = gb_trees_from_list([{0,term}]),
- Vst#vst{current=St#st{x=Xs,ct=Fails,fls=undefined}};
+ Xregs = gb_trees:enter(0, term, St#st.x),
+ Vst#vst{current=St#st{x=Xregs,ct=Fails,fls=undefined}};
Type ->
error({bad_type,Type})
end;
-valfun_1({try_end,Reg}, #vst{current=#st{ct=[Fail|Fails]}=St0}=Vst0) ->
- case get_special_y_type(Reg, Vst0) of
+valfun_1({try_end,Reg}, #vst{current=#st{ct=[Fail|Fails]}=St0}=Vst) ->
+ case get_special_y_type(Reg, Vst) of
{trytag,Fail} ->
- Vst = case Fail of
- [FailLabel] -> branch_state(FailLabel, Vst0);
- _ -> Vst0
- end,
St = St0#st{ct=Fails,fls=undefined},
set_catch_end(Reg, Vst#vst{current=St});
Type ->
@@ -464,14 +456,34 @@ valfun_1({get_tl,Src,Dst}, Vst) ->
valfun_1({get_tuple_element,Src,I,Dst}, Vst) ->
assert_type({tuple_element,I+1}, Src, Vst),
set_type_reg(term, Src, Dst, Vst);
+valfun_1({jump,{f,Lbl}}, Vst) ->
+ kill_state(branch_state(Lbl, Vst));
valfun_1(I, Vst) ->
valfun_2(I, Vst).
+init_try_catch_branch(Tag, Dst, Fail, Vst0) ->
+ Vst1 = set_type_y({Tag,[Fail]}, Dst, Vst0),
+ #vst{current=#st{ct=Fails}=St0} = Vst1,
+ CurrentSt = St0#st{ct=[[Fail]|Fails]},
+
+ %% Set the initial state at the try/catch label.
+ %% Assume that Y registers contain terms or try/catch
+ %% tags.
+ Yregs0 = map(fun({Y,uninitialized}) -> {Y,term};
+ ({Y,initialized}) -> {Y,term};
+ (E) -> E
+ end, gb_trees:to_list(CurrentSt#st.y)),
+ Yregs = gb_trees:from_orddict(Yregs0),
+ BranchSt = CurrentSt#st{y=Yregs},
+
+ Vst = branch_state(Fail, Vst1#vst{current=BranchSt}),
+ Vst#vst{current=CurrentSt}.
+
%% Update branched state if necessary and try next set of instructions.
valfun_2(I, #vst{current=#st{ct=[]}}=Vst) ->
valfun_3(I, Vst);
valfun_2(I, #vst{current=#st{ct=[[Fail]|_]}}=Vst) when is_integer(Fail) ->
- %% Update branched state
+ %% Update branched state.
valfun_3(I, branch_state(Fail, Vst));
valfun_2(_, _) ->
error(ambiguous_catch_try_state).
@@ -587,8 +599,6 @@ valfun_4(return, #vst{current=#st{numy=none}}=Vst) ->
kill_state(Vst);
valfun_4(return, #vst{current=#st{numy=NumY}}) ->
error({stack_frame,NumY});
-valfun_4({jump,{f,Lbl}}, Vst) ->
- kill_state(branch_state(Lbl, Vst));
valfun_4({loop_rec,{f,Fail},Dst}, Vst0) ->
Vst = branch_state(Fail, Vst0),
%% This term may not be part of the root set until
@@ -885,15 +895,7 @@ val_dsetel(_, #vst{current=#st{setelem=true}=St}=Vst) ->
Vst#vst{current=St#st{setelem=false}};
val_dsetel(_, Vst) -> Vst.
-kill_state(#vst{current=#st{ct=[[Fail]|_]}}=Vst) when is_integer(Fail) ->
- %% There is an active catch. Make sure that we merge the state into
- %% the catch label before clearing it, so that that we can be sure
- %% that the label gets a state.
- kill_state_1(branch_state(Fail, Vst));
kill_state(Vst) ->
- kill_state_1(Vst).
-
-kill_state_1(Vst) ->
Vst#vst{current=none}.
%% A "plain" call.