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authorJohn Högberg <[email protected]>2019-06-28 08:25:00 +0200
committerJohn Högberg <[email protected]>2019-07-03 10:44:29 +0200
commit3dd5ab9473f888ceb8f2ae6d71f51cd92de83f5b (patch)
tree862dd7bf9c091da6a7013052aac2d13405314b5d
parent4319a7f8bc93388ec540e954eb9bb73ea1eec4ef (diff)
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beam_ssa_opt: Do not apply tuple_size optimization outside guards
Rewriting `tuple_size` to `is_tuple` + `tuple_size` will cause it not to throw an exception, either crashing the compiler or the emulator when the code runs.
-rw-r--r--lib/compiler/src/beam_ssa_opt.erl66
-rw-r--r--lib/compiler/test/match_SUITE.erl21
2 files changed, 58 insertions, 29 deletions
diff --git a/lib/compiler/src/beam_ssa_opt.erl b/lib/compiler/src/beam_ssa_opt.erl
index 90c0d3cf16..229edc6a1d 100644
--- a/lib/compiler/src/beam_ssa_opt.erl
+++ b/lib/compiler/src/beam_ssa_opt.erl
@@ -904,8 +904,7 @@ cse_suitable(#b_set{}) -> false.
}).
ssa_opt_float({#st{ssa=Linear0,cnt=Count0}=St, FuncDb}) ->
- NonGuards0 = float_non_guards(Linear0),
- NonGuards = gb_sets:from_list(NonGuards0),
+ NonGuards = non_guards(Linear0),
Blocks = maps:from_list(Linear0),
Fs = #fs{non_guards=NonGuards,bs=Blocks},
{Linear,Count} = float_opt(Linear0, Count0, Fs),
@@ -916,15 +915,6 @@ float_blk_is_in_guard(#b_blk{last=#b_br{fail=F}}, #fs{non_guards=NonGuards}) ->
float_blk_is_in_guard(#b_blk{}, #fs{}) ->
false.
-float_non_guards([{L,#b_blk{is=Is}}|Bs]) ->
- case Is of
- [#b_set{op=landingpad}|_] ->
- [L|float_non_guards(Bs)];
- _ ->
- float_non_guards(Bs)
- end;
-float_non_guards([]) -> [?BADARG_BLOCK].
-
float_opt([{L,Blk}|Bs0], Count0, Fs) ->
case float_blk_is_in_guard(Blk, Fs) of
true ->
@@ -1774,35 +1764,44 @@ opt_bs_put_split_int_1(Int, L, R) ->
%%%
ssa_opt_tuple_size({#st{ssa=Linear0,cnt=Count0}=St, FuncDb}) ->
- {Linear,Count} = opt_tup_size(Linear0, Count0, []),
+ %% This optimization is only safe in guards, as prefixing tuple_size with
+ %% an is_tuple check prevents it from throwing an exception.
+ NonGuards = non_guards(Linear0),
+ {Linear,Count} = opt_tup_size(Linear0, NonGuards, Count0, []),
{St#st{ssa=Linear,cnt=Count}, FuncDb}.
-opt_tup_size([{L,#b_blk{is=Is,last=Last}=Blk}|Bs], Count0, Acc0) ->
+opt_tup_size([{L,#b_blk{is=Is,last=Last}=Blk}|Bs], NonGuards, Count0, Acc0) ->
case {Is,Last} of
{[#b_set{op={bif,'=:='},dst=Bool,args=[#b_var{}=Tup,#b_literal{val=Arity}]}],
#b_br{bool=Bool}} when is_integer(Arity), Arity >= 0 ->
- {Acc,Count} = opt_tup_size_1(Tup, L, Count0, Acc0),
- opt_tup_size(Bs, Count, [{L,Blk}|Acc]);
+ {Acc,Count} = opt_tup_size_1(Tup, L, NonGuards, Count0, Acc0),
+ opt_tup_size(Bs, NonGuards, Count, [{L,Blk}|Acc]);
{_,_} ->
- opt_tup_size(Bs, Count0, [{L,Blk}|Acc0])
+ opt_tup_size(Bs, NonGuards, Count0, [{L,Blk}|Acc0])
end;
-opt_tup_size([], Count, Acc) ->
+opt_tup_size([], _NonGuards, Count, Acc) ->
{reverse(Acc),Count}.
-opt_tup_size_1(Size, EqL, Count0, [{L,Blk0}|Acc]) ->
- case Blk0 of
- #b_blk{is=Is0,last=#b_br{bool=Bool,succ=EqL,fail=Fail}} ->
- case opt_tup_size_is(Is0, Bool, Size, []) of
- none ->
+opt_tup_size_1(Size, EqL, NonGuards, Count0, [{L,Blk0}|Acc]) ->
+ #b_blk{is=Is0,last=Last} = Blk0,
+ case Last of
+ #b_br{bool=Bool,succ=EqL,fail=Fail} ->
+ case gb_sets:is_member(Fail, NonGuards) of
+ true ->
{[{L,Blk0}|Acc],Count0};
- {PreIs,TupleSizeIs,Tuple} ->
- opt_tup_size_2(PreIs, TupleSizeIs, L, EqL,
- Tuple, Fail, Count0, Acc)
+ false ->
+ case opt_tup_size_is(Is0, Bool, Size, []) of
+ none ->
+ {[{L,Blk0}|Acc],Count0};
+ {PreIs,TupleSizeIs,Tuple} ->
+ opt_tup_size_2(PreIs, TupleSizeIs, L, EqL,
+ Tuple, Fail, Count0, Acc)
+ end
end;
- #b_blk{} ->
+ _ ->
{[{L,Blk0}|Acc],Count0}
end;
-opt_tup_size_1(_, _, Count, Acc) ->
+opt_tup_size_1(_, _, _, Count, Acc) ->
{Acc,Count}.
opt_tup_size_2(PreIs, TupleSizeIs, PreL, EqL, Tuple, Fail, Count0, Acc) ->
@@ -2241,6 +2240,19 @@ gcd(A, B) ->
X -> gcd(B, X)
end.
+non_guards(Linear) ->
+ gb_sets:from_list(non_guards_1(Linear)).
+
+non_guards_1([{L,#b_blk{is=Is}}|Bs]) ->
+ case Is of
+ [#b_set{op=landingpad}|_] ->
+ [L | non_guards_1(Bs)];
+ _ ->
+ non_guards_1(Bs)
+ end;
+non_guards_1([]) ->
+ [?BADARG_BLOCK].
+
rel2fam(S0) ->
S1 = sofs:relation(S0),
S = sofs:rel2fam(S1),
diff --git a/lib/compiler/test/match_SUITE.erl b/lib/compiler/test/match_SUITE.erl
index aac9de278d..bc74ec4984 100644
--- a/lib/compiler/test/match_SUITE.erl
+++ b/lib/compiler/test/match_SUITE.erl
@@ -25,7 +25,8 @@
match_in_call/1,untuplify/1,shortcut_boolean/1,letify_guard/1,
selectify/1,deselectify/1,underscore/1,match_map/1,map_vars_used/1,
coverage/1,grab_bag/1,literal_binary/1,
- unary_op/1,eq_types/1,match_after_return/1,match_right_tuple/1]).
+ unary_op/1,eq_types/1,match_after_return/1,match_right_tuple/1,
+ tuple_size_in_try/1]).
-include_lib("common_test/include/ct.hrl").
@@ -41,7 +42,8 @@ groups() ->
shortcut_boolean,letify_guard,selectify,deselectify,
underscore,match_map,map_vars_used,coverage,
grab_bag,literal_binary,unary_op,eq_types,
- match_after_return,match_right_tuple]}].
+ match_after_return,match_right_tuple,
+ tuple_size_in_try]}].
init_per_suite(Config) ->
@@ -922,4 +924,19 @@ match_right_tuple_1(T) ->
force_succ_regs(_A, B) -> B.
+tuple_size_in_try(Config) when is_list(Config) ->
+ %% The tuple_size optimization was applied outside of guards, causing
+ %% either the emulator or compiler to crash.
+ ok = tsit(gurka),
+ ok = tsit(gaffel).
+
+tsit(A) ->
+ try
+ id(ignored),
+ 1 = tuple_size(A),
+ error
+ catch
+ _:_ -> ok
+ end.
+
id(I) -> I.