Merge branch 'bjorn/create-less-garbage'

* bjorn/create-less-garbage:
  Optimize filename:basename/1 to produce less garbage
  Optimize filename:extension/1 to produce less garbage
  sys.c for Unix: Undo caching of utsname in os_flavor()
  Pre-build the tuples returned by os:type/0 and os:version/0

3 files changed, 48 insertions, 42 deletions

diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index e17325b64f..de5e4046fa 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -119,6 +119,10 @@ static char erts_system_version[] = ("Erlang " ERLANG_OTP_RELEASE
 # define PERFMON_GETPCR			_IOR('P', 2, unsigned long long)
 #endif
 
+/* Cached, pre-built {OsType,OsFlavor} and {Major,Minor,Build} tuples */
+static Eterm os_type_tuple;
+static Eterm os_version_tuple;
+
 static Eterm
 current_function(Process* p, Process* rp, Eterm** hpp, int full_info);
 static Eterm current_stacktrace(Process* p, Process* rp, Eterm** hpp);
@@ -2227,16 +2231,7 @@ BIF_RETTYPE system_info_1(BIF_ALIST_1)
 	return erts_instr_get_type_info(BIF_P);
     }
     else if (BIF_ARG_1 == am_os_type) {
-       Eterm type = am_atom_put(os_type, strlen(os_type));
-       Eterm flav, tup;
-       char *buf = erts_alloc(ERTS_ALC_T_TMP, 1024); /* More than enough */
-
-       os_flavor(buf, 1024);
-       flav = am_atom_put(buf, strlen(buf));
-       hp = HAlloc(BIF_P, 3);
-       tup = TUPLE2(hp, type, flav);
-       erts_free(ERTS_ALC_T_TMP, (void *) buf);
-       BIF_RET(tup);
+	BIF_RET(os_type_tuple);
     }
     else if (BIF_ARG_1 == am_allocator) {
 	BIF_RET(erts_allocator_options((void *) BIF_P));
@@ -2262,16 +2257,7 @@ BIF_RETTYPE system_info_1(BIF_ALIST_1)
         BIF_RET(am_false);
     }
     else if (BIF_ARG_1 == am_os_version) {
-       int major, minor, build;
-       Eterm tup;
-
-       os_version(&major, &minor, &build);
-       hp = HAlloc(BIF_P, 4);
-       tup = TUPLE3(hp,
-		    make_small(major),
-		    make_small(minor),
-		    make_small(build));
-       BIF_RET(tup);
+	BIF_RET(os_version_tuple);
     }
     else if (BIF_ARG_1 == am_version) {
 	int n = strlen(ERLANG_VERSION);
@@ -4107,6 +4093,27 @@ BIF_RETTYPE erts_debug_lock_counters_1(BIF_ALIST_1)
     BIF_ERROR(BIF_P, BADARG);
 }
 
+static void os_info_init(void)
+{
+    Eterm type = am_atom_put(os_type, strlen(os_type));
+    Eterm flav;
+    int major, minor, build;
+    char* buf = erts_alloc(ERTS_ALC_T_TMP, 1024); /* More than enough */
+    Eterm* hp;
+
+    os_flavor(buf, 1024);
+    flav = am_atom_put(buf, strlen(buf));
+    erts_free(ERTS_ALC_T_TMP, (void *) buf);
+    hp = erts_alloc(ERTS_ALC_T_LL_TEMP_TERM, (3+4)*sizeof(Eterm));
+    os_type_tuple = TUPLE2(hp, type, flav);
+    hp += 3;
+    os_version(&major, &minor, &build);
+    os_version_tuple = TUPLE3(hp,
+			      make_small(major),
+			      make_small(minor),
+			      make_small(build));
+}
+
 void
 erts_bif_info_init(void)
 {
@@ -4114,4 +4121,5 @@ erts_bif_info_init(void)
     erts_smp_atomic_init_nob(&hipe_test_reschedule_flag, 0);
 
     process_info_init();
+    os_info_init();
 }
diff --git a/erts/emulator/sys/unix/sys.c b/erts/emulator/sys/unix/sys.c
index 94ec8dc8a0..20bfaad9aa 100644
--- a/erts/emulator/sys/unix/sys.c
+++ b/erts/emulator/sys/unix/sys.c
@@ -931,18 +931,13 @@ void
 os_flavor(char* namebuf, 	/* Where to return the name. */
 	  unsigned size) 	/* Size of name buffer. */
 {
-    static int called = 0;
-    static struct utsname uts;	/* Information about the system. */
-
-    if (!called) {
-	char* s;
+    struct utsname uts;		/* Information about the system. */
+    char* s;
 
-	(void) uname(&uts);
-	called = 1;
-	for (s = uts.sysname; *s; s++) {
-	    if (isupper((int) *s)) {
-		*s = tolower((int) *s);
-	    }
+    (void) uname(&uts);
+    for (s = uts.sysname; *s; s++) {
+	if (isupper((int) *s)) {
+	    *s = tolower((int) *s);
 	}
     }
     strcpy(namebuf, uts.sysname);
diff --git a/lib/stdlib/src/filename.erl b/lib/stdlib/src/filename.erl
index 1cb9e4a25e..2fc9128e4e 100644
--- a/lib/stdlib/src/filename.erl
+++ b/lib/stdlib/src/filename.erl
@@ -147,9 +147,10 @@ basename(Name) when is_binary(Name) ->
     end;
     
 basename(Name0) ->
-    Name = flatten(Name0),
+    Name1 = flatten(Name0),
     {DirSep2, DrvSep} = separators(),
-    basename1(skip_prefix(Name, DrvSep), [], DirSep2).
+    Name = skip_prefix(Name1, DrvSep),
+    basename1(Name, Name, DirSep2).
 
 win_basenameb(<<Letter,$:,Rest/binary>>) when ?IS_DRIVELETTER(Letter) ->
     basenameb(Rest,[<<"/">>,<<"\\">>]);
@@ -167,16 +168,18 @@ basenameb(Bin,Sep) ->
     
 
 
-basename1([$/|[]], Tail, DirSep2) ->
-    basename1([], Tail, DirSep2);
+basename1([$/], Tail0, _DirSep2) ->
+    %% End of filename -- must get rid of trailing directory separator.
+    [_|Tail] = lists:reverse(Tail0),
+    lists:reverse(Tail);
 basename1([$/|Rest], _Tail, DirSep2) ->
-    basename1(Rest, [], DirSep2);
+    basename1(Rest, Rest, DirSep2);
 basename1([DirSep2|Rest], Tail, DirSep2) when is_integer(DirSep2) ->
     basename1([$/|Rest], Tail, DirSep2);
 basename1([Char|Rest], Tail, DirSep2) when is_integer(Char) ->
-    basename1(Rest, [Char|Tail], DirSep2);
+    basename1(Rest, Tail, DirSep2);
 basename1([], Tail, _DirSep2) ->
-    lists:reverse(Tail).
+    Tail.
 
 skip_prefix(Name, false) ->
     Name;
@@ -369,8 +372,8 @@ extension(Name0) ->
     Name = flatten(Name0),
     extension(Name, [], major_os_type()).
 
-extension([$.|Rest], _Result, OsType) ->
-    extension(Rest, [$.], OsType);
+extension([$.|Rest]=Result, _Result, OsType) ->
+    extension(Rest, Result, OsType);
 extension([Char|Rest], [], OsType) when is_integer(Char) ->
     extension(Rest, [], OsType);
 extension([$/|Rest], _Result, OsType) ->
@@ -378,9 +381,9 @@ extension([$/|Rest], _Result, OsType) ->
 extension([$\\|Rest], _Result, win32) ->
     extension(Rest, [], win32);
 extension([Char|Rest], Result, OsType) when is_integer(Char) ->
-    extension(Rest, [Char|Result], OsType);
+    extension(Rest, Result, OsType);
 extension([], Result, _OsType) ->
-    lists:reverse(Result).
+    Result.
 
 %% Joins a list of filenames with directory separators.