Merge pull request erlang#7285 from bjorng/bjorn/compiler/fix-beam_ss…

…a_codegen-crash/erlangGH-7283 Eliminate crash in beam_ssa_codegen
kevsmith · May 26, 2023 · 38fb8bf · 38fb8bf
2 parents 718a323 + 91e0c5d
commit 38fb8bf
Show file tree

Hide file tree

Showing 2 changed files with 26 additions and 0 deletions.
diff --git a/lib/compiler/src/beam_ssa_codegen.erl b/lib/compiler/src/beam_ssa_codegen.erl
@@ -1814,6 +1814,18 @@ cg_instr(bs_get_position, [Ctx], Dst, Set) ->
 cg_instr(put_map, [{atom,assoc},SrcMap|Ss], Dst, Set) ->
     Live = get_live(Set),
     [{put_map_assoc,{f,0},SrcMap,Dst,Live,{list,Ss}}];
+cg_instr(put_map, [{atom,exact},SrcBadMap|_Ss], _Dst, #cg_set{anno=Anno}=Set) ->
+    %% GH-7283: An exact `put_map` without a failure label was not
+    %% handled. The absence of the failure label can only mean that
+    %% the source is known not to be a valid map. (None of the current
+    %% optimization passes can figure out that the key is always
+    %% present in the map and that the operation therefore can never
+    %% fail.)
+    Live = get_live(Set),
+    [{test_heap,3,Live},
+     {put_tuple2,{x,0},{list,[{atom,badmap},SrcBadMap]}},
+     line(Anno),
+     {call_ext_last,1,{extfunc,erlang,error,1},1}];
 cg_instr(is_nonempty_list, Ss, Dst, Set) ->
     #cg_set{anno=#{was_bif_is_list := true}} = Set, %Assertion.
 

diff --git a/lib/compiler/test/beam_ssa_SUITE.erl b/lib/compiler/test/beam_ssa_SUITE.erl
@@ -454,6 +454,10 @@ maps(_Config) ->
 
     [] = maps_3(),
 
+    {'EXIT',{{badmap,true},_}} = catch maps_4(id(true), id(true)),
+    error = maps_4(id(#{}), id(true)),
+    error = maps_4(id(#{}), id(#{})),
+
     ok.
 
 maps_1(K) ->
@@ -535,6 +539,16 @@ maps_3() ->
                  []
          end -- [].
 
+maps_4(A, B = A) when B; A ->
+    A#{ok := ok},
+    try A of
+        B -> B
+    after
+        ok
+    end#{ok := ok};
+maps_4(_, _) ->
+    error.
+
 -record(wx_ref, {type=any_type,ref=any_ref}).
 
 cover_ssa_dead(_Config) ->