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-rw-r--r--lib/compiler/src/beam_bool.erl23
-rw-r--r--lib/compiler/test/guard_SUITE.erl18
2 files changed, 37 insertions, 4 deletions
diff --git a/lib/compiler/src/beam_bool.erl b/lib/compiler/src/beam_bool.erl
index dc4d7927e9..a452d30b61 100644
--- a/lib/compiler/src/beam_bool.erl
+++ b/lib/compiler/src/beam_bool.erl
@@ -163,7 +163,16 @@ bopt_block(Reg, Fail, OldIs, [{block,Bl0}|Acc0], St0) ->
%% in guards, so it must have been another
%% Core Erlang translator.)
throw:protected_violation ->
+ failed;
+
+ %% Failed to work out the live registers for a GC
+ %% BIF. For example, if the number of live registers
+ %% needed to be 4 because {x,3} was a source register,
+ %% but {x,2} was not known to be initialized, this
+ %% exception would be thrown.
+ throw:gc_bif_alloc_failure ->
failed
+
end
end.
@@ -665,10 +674,16 @@ put_reg_1(V, [], I) -> [{I,V}].
fetch_reg(V, [{I,V}|_]) -> {x,I};
fetch_reg(V, [_|SRs]) -> fetch_reg(V, SRs).
-live_regs(Regs) ->
- foldl(fun ({I,_}, _) ->
- I
- end, -1, Regs)+1.
+live_regs([{_,reserved}|_]) ->
+ %% We are not sure that this register is initialized, so we must
+ %% abort the optimization.
+ throw(gc_bif_alloc_failure);
+live_regs([{I,_}]) ->
+ I+1;
+live_regs([{_,_}|Regs]) ->
+ live_regs(Regs);
+live_regs([]) ->
+ 0.
%%%
diff --git a/lib/compiler/test/guard_SUITE.erl b/lib/compiler/test/guard_SUITE.erl
index eb205d09a7..34bfdeb1e5 100644
--- a/lib/compiler/test/guard_SUITE.erl
+++ b/lib/compiler/test/guard_SUITE.erl
@@ -1556,6 +1556,24 @@ bad_constants(Config) when is_list(Config) ->
bad_guards(Config) when is_list(Config) ->
if erlang:float(self()); true -> ok end,
+
+ fc(catch bad_guards_1(1, [])),
+ fc(catch bad_guards_1(1, [2])),
+ fc(catch bad_guards_1(atom, [2])),
+
+ fc(catch bad_guards_2(#{a=>0,b=>0}, [])),
+ fc(catch bad_guards_2(#{a=>0,b=>0}, [x])),
+ fc(catch bad_guards_2(not_a_map, [x])),
+ fc(catch bad_guards_2(42, [x])),
+ ok.
+
+%% beam_bool used to produce GC BIF instructions whose
+%% Live operands included uninitialized registers.
+
+bad_guards_1(X, [_]) when {{X}}, -X ->
+ ok.
+
+bad_guards_2(M, [_]) when M#{a := 0, b => 0}, map_size(M) ->
ok.
%% Call this function to turn off constant propagation.