From d39cac954fc76a838763ac1ac03cb71bf8e5d68d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Thu, 11 Aug 2016 15:35:29 +0200
Subject: [ERL-209] Fix ambiguous_catch_try_state inconsistency error
It is not safe to share code between 'catch' blocks.
---
lib/compiler/src/beam_jump.erl | 22 ++++++++++++++--------
lib/compiler/test/beam_jump_SUITE.erl | 19 +++++++++++++++++--
2 files changed, 31 insertions(+), 10 deletions(-)
(limited to 'lib')
diff --git a/lib/compiler/src/beam_jump.erl b/lib/compiler/src/beam_jump.erl
index 09cd3aa2d4..48b5a32814 100644
--- a/lib/compiler/src/beam_jump.erl
+++ b/lib/compiler/src/beam_jump.erl
@@ -167,12 +167,18 @@ share_1([{label,L}=Lbl|Is], Dict0, Seq, Acc) ->
end;
share_1([{func_info,_,_,_}=I|Is], _, [], Acc) ->
reverse(Is, [I|Acc]);
+share_1([{'catch',_,_}=I|Is], Dict0, Seq, Acc) ->
+ Dict = clean_non_sharable(Dict0),
+ share_1(Is, Dict, [I|Seq], 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([{catch_end,_}=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 ->
@@ -182,18 +188,18 @@ share_1([I|Is], Dict, Seq, 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.
+ %% We are passing in or out of a 'catch' or 'try' block. Remove
+ %% sequences that should not be shared over the boundaries of the
+ %% block. Since the end of the sequence must match, the only
+ %% possible match between a sequence outside and a sequence inside
+ %% the 'catch'/'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.
maps: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
+ %% match a sequence on the other side of the 'catch'/'try' block
%% boundary.
false;
sharable_with_try([_|Is]) ->
diff --git a/lib/compiler/test/beam_jump_SUITE.erl b/lib/compiler/test/beam_jump_SUITE.erl
index 0b13adaff2..088f63606c 100644
--- a/lib/compiler/test/beam_jump_SUITE.erl
+++ b/lib/compiler/test/beam_jump_SUITE.erl
@@ -21,7 +21,7 @@
-export([all/0,suite/0,groups/0,init_per_suite/1,end_per_suite/1,
init_per_group/2,end_per_group/2,
- undefined_label/1]).
+ undefined_label/1,ambiguous_catch_try_state/1]).
suite() ->
[{ct_hooks,[ts_install_cth]}].
@@ -32,7 +32,8 @@ all() ->
groups() ->
[{p,[parallel],
- [undefined_label
+ [undefined_label,
+ ambiguous_catch_try_state
]}].
init_per_suite(Config) ->
@@ -57,3 +58,17 @@ flights(0, [], []) when [], 0; 0.0, [], false ->
clark;
flights(_, Reproduction, introduction) when false, Reproduction ->
responsible.
+
+%% [ERL-209] beam_jump would share 'catch' blocks, causing an
+%% ambiguous_catch_try_state error in beam_validator.
+
+ambiguous_catch_try_state(_Config) ->
+ {{'EXIT',{{case_clause,song},_}},{'EXIT',{{case_clause,song},_}}} =
+ checks(42),
+ ok.
+
+river() -> song.
+
+checks(Wanted) ->
+ %% Must be one line to cause the unsafe optimization.
+ {catch case river() of sheet -> begin +Wanted, if "da" -> Wanted end end end, catch case river() of sheet -> begin + Wanted, if "da" -> Wanted end end end}.
--
cgit v1.2.3