erts: add erlang:system_info(atom_count)

4 files changed, 30 insertions, 8 deletions

diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index 3dad09365e..40ddcb8545 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -7224,8 +7224,8 @@ ok
     </func>
 
     <func>
-      <name name="system_info" arity="1" clause_i="11"/>
       <name name="system_info" arity="1" clause_i="12"/>
+      <name name="system_info" arity="1" clause_i="13"/>
       <fsummary>Information about the CPU topology of the system.</fsummary>
       <type name="cpu_topology"/>
       <type name="level_entry"/>
@@ -7325,12 +7325,12 @@ ok
     </func>
 
     <func>
-      <name name="system_info" arity="1" clause_i="28"/>
       <name name="system_info" arity="1" clause_i="29"/>
-      <name name="system_info" arity="1" clause_i="37"/>
+      <name name="system_info" arity="1" clause_i="30"/>
       <name name="system_info" arity="1" clause_i="38"/>
       <name name="system_info" arity="1" clause_i="39"/>
       <name name="system_info" arity="1" clause_i="40"/>
+      <name name="system_info" arity="1" clause_i="41"/>
       <fsummary>Information about the default process heap settings.</fsummary>
       <type name="message_queue_data"/>
       <type name="max_heap_size"/>
@@ -7408,7 +7408,7 @@ ok
       <name name="system_info" arity="1" clause_i="8"/>
       <name name="system_info" arity="1" clause_i="9"/>
       <name name="system_info" arity="1" clause_i="10"/>
-      <name name="system_info" arity="1" clause_i="13"/>
+      <name name="system_info" arity="1" clause_i="11"/>
       <name name="system_info" arity="1" clause_i="14"/>
       <name name="system_info" arity="1" clause_i="15"/>
       <name name="system_info" arity="1" clause_i="16"/>
@@ -7423,14 +7423,14 @@ ok
       <name name="system_info" arity="1" clause_i="25"/>
       <name name="system_info" arity="1" clause_i="26"/>
       <name name="system_info" arity="1" clause_i="27"/>
-      <name name="system_info" arity="1" clause_i="30"/>
+      <name name="system_info" arity="1" clause_i="28"/>
       <name name="system_info" arity="1" clause_i="31"/>
       <name name="system_info" arity="1" clause_i="32"/>
       <name name="system_info" arity="1" clause_i="33"/>
       <name name="system_info" arity="1" clause_i="34"/>
       <name name="system_info" arity="1" clause_i="35"/>
       <name name="system_info" arity="1" clause_i="36"/>
-      <name name="system_info" arity="1" clause_i="41"/>
+      <name name="system_info" arity="1" clause_i="37"/>
       <name name="system_info" arity="1" clause_i="42"/>
       <name name="system_info" arity="1" clause_i="43"/>
       <name name="system_info" arity="1" clause_i="44"/>
@@ -7460,11 +7460,18 @@ ok
       <name name="system_info" arity="1" clause_i="68"/>
       <name name="system_info" arity="1" clause_i="69"/>
       <name name="system_info" arity="1" clause_i="70"/>
+      <name name="system_info" arity="1" clause_i="71"/>
       <fsummary>Information about the system.</fsummary>
       <desc>
         <p>Returns various information about the current system
           (emulator) as specified by <c><anno>Item</anno></c>:</p>
         <taglist>
+          <tag><c>atom_count</c></tag>
+          <item>
+            <marker id="system_info_atom_count"></marker>
+            <p>Returns the number of atoms currently existing at the
+              local node. The value is given as an integer.</p>
+          </item>
           <tag><c>atom_limit</c></tag>
           <item>
             <marker id="system_info_atom_limit"></marker>
diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index 0e0842e139..9a3b78ae8d 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -2863,6 +2863,9 @@ BIF_RETTYPE system_info_1(BIF_ALIST_1)
     else if (ERTS_IS_ATOM_STR("atom_limit",BIF_ARG_1)) {
         BIF_RET(make_small(erts_get_atom_limit()));
     }
+    else if (ERTS_IS_ATOM_STR("atom_count",BIF_ARG_1)) {
+        BIF_RET(make_small(atom_table_size()));
+    }
     else if (ERTS_IS_ATOM_STR("tolerant_timeofday",BIF_ARG_1)) {
 	if (erts_has_time_correction()
 	    && erts_time_offset_state() == ERTS_TIME_OFFSET_FINAL) {
diff --git a/erts/emulator/test/system_info_SUITE.erl b/erts/emulator/test/system_info_SUITE.erl
index 3d9e74472b..6a772bf7c9 100644
--- a/erts/emulator/test/system_info_SUITE.erl
+++ b/erts/emulator/test/system_info_SUITE.erl
@@ -36,7 +36,8 @@
 -export([all/0, suite/0]).
 
 -export([process_count/1, system_version/1, misc_smoke_tests/1,
-         heap_size/1, wordsize/1, memory/1, ets_limit/1, atom_limit/1]).
+         heap_size/1, wordsize/1, memory/1, ets_limit/1, atom_limit/1,
+         atom_count/1]).
 
 suite() ->
     [{ct_hooks,[ts_install_cth]},
@@ -44,7 +45,7 @@ suite() ->
 
 all() -> 
     [process_count, system_version, misc_smoke_tests,
-     heap_size, wordsize, memory, ets_limit, atom_limit].
+     heap_size, wordsize, memory, ets_limit, atom_limit, atom_count].
 
 %%%
 %%% The test cases -------------------------------------------------------------
@@ -550,3 +551,13 @@ get_atom_limit(Config, AtomsMax) ->
     end,
     stop_node(Node),
     Res.
+
+%% Verify that system_info(atom_count) works.
+atom_count(Config) when is_list(Config) ->
+    Limit = erlang:system_info(atom_limit),
+    Count1 = erlang:system_info(atom_count),
+    list_to_atom(integer_to_list(erlang:unique_integer())),
+    Count2 = erlang:system_info(atom_count),
+    true = Limit >= Count2,
+    true = Count2 > Count1,
+    ok.
diff --git a/erts/preloaded/src/erlang.erl b/erts/preloaded/src/erlang.erl
index 15c3e01653..6ca0a4c160 100644
--- a/erts/preloaded/src/erlang.erl
+++ b/erts/preloaded/src/erlang.erl
@@ -2532,6 +2532,7 @@ tuple_to_list(_Tuple) ->
       Alloc :: atom();
          ({allocator_sizes, Alloc}) -> [_] when %% More or less anything
       Alloc :: atom();
+         (atom_count) -> pos_integer();
          (atom_limit) -> pos_integer();
          (build_type) -> opt | debug | purify | quantify | purecov |
                          gcov | valgrind | gprof | lcnt | frmptr;