erts: Add erts_internal:map_to_tuple_keys/1

* Used for introspection.
* Will return the internal key tuple if applicable
* Not documented - not for public use

2 files changed, 17 insertions, 0 deletions

diff --git a/erts/emulator/beam/bif.tab b/erts/emulator/beam/bif.tab
index 2d888862bf..fbdddf09db 100644
--- a/erts/emulator/beam/bif.tab
+++ b/erts/emulator/beam/bif.tab
@@ -157,6 +157,7 @@ bif erts_internal:binary_to_term/2
 bif erts_internal:request_system_task/3
 bif erts_internal:check_process_code/2
 
+bif erts_internal:map_to_tuple_keys/1
 
 # inet_db support
 bif erlang:port_set_data/2
diff --git a/erts/emulator/beam/erl_map.c b/erts/emulator/beam/erl_map.c
index fdd2d0c0f6..5e740aacdd 100644
--- a/erts/emulator/beam/erl_map.c
+++ b/erts/emulator/beam/erl_map.c
@@ -58,6 +58,8 @@
  * - maps:size/1
  * - maps:without/2
  *
+ * DEBUG: for sharing calculation
+ * - erts_internal:map_to_tuple_keys/1
  */
 
 /* erlang:map_size/1
@@ -819,3 +821,17 @@ int erts_validate_and_sort_map(map_t* mp)
     }
     return 1;
 }
+
+/*
+ * erts_internal:map_to_tuple_keys/1
+ *
+ * Used in erts_debug:size/1
+ */
+
+BIF_RETTYPE erts_internal_map_to_tuple_keys_1(BIF_ALIST_1) {
+    if (is_map(BIF_ARG_1)) {
+	map_t *mp = (map_t*)map_val(BIF_ARG_1);
+	BIF_RET(mp->keys);
+    }
+    BIF_ERROR(BIF_P, BADARG);
+}