Merge 'sverker/22/ets-matchspec-stack-bug/OTP-17379'

forward to OTP-23.3.1
as 'sverker/23/ets-matchspec-stack-bug/OTP-17379'

Author: sverker

erts/emulator/beam/erl_db_util.c

@@ -3837,6 +3837,7 @@ dmc_array(DMCContext *context, DMCHeap *heap, DMC_STACK_TYPE(UWord) *text,
 {
     int all_constant = 1;
     int textpos = DMC_STACK_NUM(*text);
+    int preventive_bumps = 0;
     Uint i;
 
     /*
@@ -3856,13 +3857,35 @@ dmc_array(DMCContext *context, DMCHeap *heap, DMC_STACK_TYPE(UWord) *text,
         if (!c && all_constant) {
             all_constant = 0;
             if (i < nelems - 1) {
+                /* Revert preventive stack bumps as they will now be done again
+                 * for real by do_emit_constant() */
+                context->stack_used -= preventive_bumps;
+
                 dmc_rearrange_constants(context, text, textpos,
                                         p + i + 1, nelems - i - 1);
             }
-        } else if (c && !all_constant) {
-            do_emit_constant(context, text, p[i]);
+        } else if (c) {
+            if (all_constant) {
+                /*
+                 * OTP-17379:
+                 * All constants so far, but do preventive stack bumps
+                 * as the constants may later be converted to matchPushC
+                 * by dmc_rearrange_constants above.
+                 * Otherwise dmc_expr() may do incorrect stack depth estimation
+                 * when it emits instructions for the first non-constant.
+                 */
+                ++context->stack_used;
+                ++preventive_bumps;
+            }
+            else {
+                do_emit_constant(context, text, p[i]);
+            }
         }
     }
+    if (all_constant) {
+        /* Preventive stack bumps not needed */
+        context->stack_used -= preventive_bumps;
+    }
     *constant = all_constant;
     return retOk;
 }

lib/stdlib/test/ets_SUITE.erl

@@ -41,7 +41,9 @@
 -export([foldl_ordered/1, foldr_ordered/1, foldl/1, foldr/1, fold_empty/1]).
 -export([t_delete_object/1, t_init_table/1, t_whitebox/1,
          select_bound_chunk/1, t_delete_all_objects/1, t_test_ms/1,
-	 t_select_delete/1,t_select_replace/1,t_select_replace_next_bug/1,t_ets_dets/1]).
+	 t_select_delete/1,t_select_replace/1,t_select_replace_next_bug/1,
+         t_select_pam_stack_overflow_bug/1,
+         t_ets_dets/1]).
 -export([t_insert_list/1, t_insert_list_bag/1, t_insert_list_duplicate_bag/1,
          t_insert_list_set/1, t_insert_list_delete_set/1,
          t_insert_list_parallel/1, t_insert_list_delete_parallel/1,
@@ -147,6 +149,7 @@ all() ->
      t_init_table, t_whitebox, t_delete_all_objects,
      t_test_ms, t_select_delete, t_select_replace,
      t_select_replace_next_bug,
+     t_select_pam_stack_overflow_bug,
      t_ets_dets, memory, t_select_reverse, t_bucket_disappears,
      t_named_select, select_fixtab_owner_change,
      select_fail, t_insert_new, t_repair_continuation,
@@ -1897,6 +1900,15 @@ t_select_replace_next_bug(Config) when is_list(Config) ->
     ets:delete(T).
 
 
+%% OTP-17379
+t_select_pam_stack_overflow_bug(Config) ->
+    T = ets:new(k, []),
+    ets:insert(T,[{x,17}]),
+    [{x,18}] = ets:select(T,[{{x,17}, [], [{{{element,1,'$_'},{const,18}}}]}]),
+    ets:delete(T),
+    ok.
+
+
 %% Test that partly bound keys gives faster matches.
 partly_bound(Config) when is_list(Config) ->
     case os:type() of