aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorBjörn Gustavsson <[email protected]>2019-05-20 11:54:22 +0200
committerBjörn Gustavsson <[email protected]>2019-05-20 13:22:55 +0200
commitcabdef3b97c077119fe6f43538dbdd5cffe9dd91 (patch)
tree87a6fe405f4d1d6f7f4e0f0db3ea4dd34688e9bb
parent6618ce7b6a621e92db72ea4f01f7d38553c8818c (diff)
downloadotp-cabdef3b97c077119fe6f43538dbdd5cffe9dd91.tar.gz
otp-cabdef3b97c077119fe6f43538dbdd5cffe9dd91.tar.bz2
otp-cabdef3b97c077119fe6f43538dbdd5cffe9dd91.zip
Fix non-terminating compilation
The compiler would not terminate while compiling the following code: foo(<<N:32>>, Tuple, NewValue) -> _ = element(N, Tuple), setelement(N, Tuple, NewValue). The type analysis pass would attempt to construct a huge list when attempting analyse the type of `Tuple` after the call to `setelement/3`. https://bugs.erlang.org/browse/ERL-948
-rw-r--r--lib/compiler/src/beam_ssa_type.erl16
-rw-r--r--lib/compiler/test/beam_type_SUITE.erl14
2 files changed, 25 insertions, 5 deletions
diff --git a/lib/compiler/src/beam_ssa_type.erl b/lib/compiler/src/beam_ssa_type.erl
index 06b42f1928..2ea7e89dfa 100644
--- a/lib/compiler/src/beam_ssa_type.erl
+++ b/lib/compiler/src/beam_ssa_type.erl
@@ -24,7 +24,7 @@
-include("beam_ssa_opt.hrl").
-import(lists, [all/2,any/2,droplast/1,foldl/3,last/1,member/2,
keyfind/3,partition/2,reverse/1,reverse/2,
- seq/2,sort/1,split/2]).
+ sort/1,split/2]).
-define(UNICODE_INT, #t_integer{elements={0,16#10FFFF}}).
@@ -874,11 +874,11 @@ type(call, [#b_remote{mod=#b_literal{val=Mod},
true ->
none
end;
- {#t_integer{elements={Min,Max}},
+ {#t_integer{elements={Min,_}}=IntType,
#t_tuple{elements=Es0,size=Size}=T} ->
- %% We know this will land between Min and Max, so kill the
- %% types for those indexes.
- Es = maps:without(seq(Min, Max), Es0),
+ %% Remove type information for all indices that
+ %% falls into the range of the integer.
+ Es = remove_element_info(IntType, Es0),
case T#t_tuple.exact of
false ->
T#t_tuple{elements=Es,size=max(Min, Size)};
@@ -1649,6 +1649,12 @@ get_literal_from_type(nil) ->
#b_literal{val=[]};
get_literal_from_type(_) -> none.
+remove_element_info(#t_integer{elements={Min,Max}}, Es) ->
+ foldl(fun(El, Acc) when Min =< El, El =< Max ->
+ maps:remove(El, Acc);
+ (_El, Acc) -> Acc
+ end, Es, maps:keys(Es)).
+
t_atom() ->
#t_atom{elements=any}.
diff --git a/lib/compiler/test/beam_type_SUITE.erl b/lib/compiler/test/beam_type_SUITE.erl
index 882e281a44..0d1680fb15 100644
--- a/lib/compiler/test/beam_type_SUITE.erl
+++ b/lib/compiler/test/beam_type_SUITE.erl
@@ -271,8 +271,22 @@ setelement(_Config) ->
T0 = id({a,42}),
{a,_} = T0,
{b,_} = setelement(1, T0, b),
+ {z,b} = do_setelement_1(<<(id(1)):32>>, {a,b}, z),
+ {new,two} = do_setelement_2(<<(id(1)):1>>, {one,two}, new),
ok.
+do_setelement_1(<<N:32>>, Tuple, NewValue) ->
+ _ = element(N, Tuple),
+ %% While updating the type for Tuple, beam_ssa_type would do:
+ %% maps:without(lists:seq(0, 4294967295), Elements)
+ setelement(N, Tuple, NewValue).
+
+do_setelement_2(<<N:1>>, Tuple, NewValue) ->
+ %% Cover the second clause in remove_element_info/2. The
+ %% type for the second element will be kept.
+ two = element(2, Tuple),
+ setelement(N, Tuple, NewValue).
+
cons(_Config) ->
[did] = cons(assigned, did),