Add erlang:check_old_code/1

Add erlang:check_old_code/1 to quickly check whether a module
has old code. If there is no old code, there is no need to call
erlang:check_process_code/2 for all processes, which will save
some time if there are many processes.

4 files changed, 65 insertions, 2 deletions

diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index 7cfab0785d..ad7a57bd73 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -518,6 +518,18 @@
     </func>
 
     <func>
+      <name>check_old_code(Module) -> boolean()</name>
+      <fsummary>Check if a module has old code</fsummary>
+      <type>
+        <v>Module = atom()</v>
+      </type>
+      <desc>
+        <p>Returns <c>true</c> if the <c>Module</c> has old code,
+	and <c>false</c> otherwise.</p>
+        <p>See also <seealso marker="kernel:code">code(3)</seealso>.</p>
+      </desc>
+    </func>
+    <func>
       <name>check_process_code(Pid, Module) -> boolean()</name>
       <fsummary>Check if a process is executing old code for a module</fsummary>
       <type>
diff --git a/erts/emulator/beam/beam_bif_load.c b/erts/emulator/beam/beam_bif_load.c
index 7b5781beeb..2561d7a630 100644
--- a/erts/emulator/beam/beam_bif_load.c
+++ b/erts/emulator/beam/beam_bif_load.c
@@ -162,6 +162,23 @@ BIF_RETTYPE code_make_stub_module_3(BIF_ALIST_3)
     return res;
 }
 
+BIF_RETTYPE
+check_old_code_1(BIF_ALIST_1)
+{
+    Module* modp;
+
+    if (is_not_atom(BIF_ARG_1)) {
+	BIF_ERROR(BIF_P, BADARG);
+    }
+    modp = erts_get_module(BIF_ARG_1);
+    if (modp == NULL) {		/* Doesn't exist. */
+	BIF_RET(am_false);
+    } else if (modp->old_code == NULL) { /* No old code. */
+	BIF_RET(am_false);
+    }
+    BIF_RET(am_true);
+}
+
 Eterm
 check_process_code_2(BIF_ALIST_2)
 {
diff --git a/erts/emulator/beam/bif.tab b/erts/emulator/beam/bif.tab
index d9dd80fa8b..b171e99e03 100644
--- a/erts/emulator/beam/bif.tab
+++ b/erts/emulator/beam/bif.tab
@@ -802,6 +802,12 @@ bif prim_file:internal_name2native/1
 bif prim_file:internal_native2name/1
 bif prim_file:internal_normalize_utf8/1
 bif file:native_name_encoding/0
+
+#
+# New in R14B04.
+#
+bif erlang:check_old_code/1
+
 #
 # Obsolete
 #
diff --git a/erts/emulator/test/code_SUITE.erl b/erts/emulator/test/code_SUITE.erl
index a062cea117..29cbdedd17 100644
--- a/erts/emulator/test/code_SUITE.erl
+++ b/erts/emulator/test/code_SUITE.erl
@@ -20,7 +20,9 @@
 -module(code_SUITE).
 -export([all/0, suite/0,groups/0,init_per_suite/1, end_per_suite/1, 
 	 init_per_group/2,end_per_group/2,
-	 new_binary_types/1,t_check_process_code/1,t_check_process_code_ets/1,
+	 new_binary_types/1,
+	 t_check_process_code/1,t_check_old_code/1,
+	 t_check_process_code_ets/1,
 	 external_fun/1,get_chunk/1,module_md5/1,make_stub/1,
 	 make_stub_many_funs/1,constant_pools/1,
 	 false_dependency/1,coverage/1]).
@@ -31,7 +33,7 @@ suite() -> [{ct_hooks,[ts_install_cth]}].
 
 all() -> 
     [new_binary_types, t_check_process_code,
-     t_check_process_code_ets, external_fun, get_chunk,
+     t_check_process_code_ets, t_check_old_code, external_fun, get_chunk,
      module_md5, make_stub, make_stub_many_funs,
      constant_pools, false_dependency, coverage].
 
@@ -248,6 +250,32 @@ fun_refc(F) ->
     Count.
 
 
+%% Test the erlang:check_old_code/1 BIF.
+t_check_old_code(Config) when is_list(Config) ->
+    ?line Data = ?config(data_dir, Config),
+    ?line File = filename:join(Data, "my_code_test"),
+
+    ?line erlang:purge_module(my_code_test),
+    ?line erlang:delete_module(my_code_test),
+    ?line catch erlang:purge_module(my_code_test),
+
+    ?line false = erlang:check_old_code(my_code_test),
+
+    ?line {ok,my_code_test,Code} = compile:file(File, [binary]),
+    ?line {module,my_code_test} = code:load_binary(my_code_test, File, Code),
+    
+    ?line false = erlang:check_old_code(my_code_test),
+    ?line {module,my_code_test} = code:load_binary(my_code_test, File, Code),
+    ?line true = erlang:check_old_code(my_code_test),
+
+    ?line true = erlang:purge_module(my_code_test),
+    ?line true = erlang:delete_module(my_code_test),
+    ?line true = erlang:purge_module(my_code_test),
+
+    ?line {'EXIT',_} = (catch erlang:check_old_code([])),
+    
+    ok.
+
 external_fun(Config) when is_list(Config) ->
     ?line false = erlang:function_exported(another_code_test, x, 1),
     ?line ExtFun = erlang:make_fun(id(another_code_test), x, 1),