[src/trunk]: src/tests/lib/libexecinfo Use conditional calls to vfork() to pr...

[joerg <joerg%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/28b1d80f4c5e
branches:  trunk
changeset: 787820:28b1d80f4c5e
user:      joerg <joerg%NetBSD.org@localhost>
date:      Thu Jul 04 23:53:13 2013 +0000

description:
Use conditional calls to vfork() to prevent the compiler from inlining
the intermediate stack frames. Mark the __start frame as optional.

diffstat:

 tests/lib/libexecinfo/Makefile      |   3 +--
 tests/lib/libexecinfo/t_backtrace.c |  30 +++++++++++++++++++++++-------
 2 files changed, 24 insertions(+), 9 deletions(-)

diffs (102 lines):

diff -r 21f9f9133b29 -r 28b1d80f4c5e tests/lib/libexecinfo/Makefile
--- a/tests/lib/libexecinfo/Makefile    Thu Jul 04 23:00:23 2013 +0000
+++ b/tests/lib/libexecinfo/Makefile    Thu Jul 04 23:53:13 2013 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: Makefile,v 1.2 2012/05/27 22:57:24 martin Exp $
+# $NetBSD: Makefile,v 1.3 2013/07/04 23:53:13 joerg Exp $
 
 .include <bsd.own.mk>
 
@@ -8,6 +8,5 @@
 
 LDADD+=                -lexecinfo -lelf
 DPADD+=                ${LIBEXECINFO} ${LIBELF}
-DBG=-O0                # prevent inlining, nothing else helps.
 
 .include <bsd.test.mk>
diff -r 21f9f9133b29 -r 28b1d80f4c5e tests/lib/libexecinfo/t_backtrace.c
--- a/tests/lib/libexecinfo/t_backtrace.c       Thu Jul 04 23:00:23 2013 +0000
+++ b/tests/lib/libexecinfo/t_backtrace.c       Thu Jul 04 23:53:13 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: t_backtrace.c,v 1.6 2013/06/06 17:40:09 joerg Exp $    */
+/*     $NetBSD: t_backtrace.c,v 1.7 2013/07/04 23:53:13 joerg Exp $    */
 
 /*-
  * Copyright (c) 2012 The NetBSD Foundation, Inc.
@@ -29,29 +29,36 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 #include <sys/cdefs.h>
-__RCSID("$NetBSD: t_backtrace.c,v 1.6 2013/06/06 17:40:09 joerg Exp $");
+__RCSID("$NetBSD: t_backtrace.c,v 1.7 2013/07/04 23:53:13 joerg Exp $");
 
 #include <atf-c.h>
 #include <atf-c/config.h>
 #include <string.h>
 #include <stdlib.h>
 #include <execinfo.h>
+#include <unistd.h>
 
 #ifndef __arraycount
 #define __arraycount(a) (sizeof(a) / sizeof(a[0]))
 #endif
 
-static void __attribute__((__noinline__))
+volatile int prevent_inline;
+
+static void
 myfunc3(size_t ncalls)
 {
        static const char *top[] = { "myfunc", "atfu_backtrace_fmt_basic_body",
            "atf_tc_run", "atf_tp_run", "atf_tp_main", "main", "___start" };
-       static bool optional_frame[] = { false, false, false, true, false, false, false };
+       static bool optional_frame[] = { false, false, false, true, false,
+           false, true };
        size_t j, nptrs, min_frames, max_frames;
        void *buffer[ncalls + 10];
        char **strings;
        __CTASSERT(__arraycount(top) == __arraycount(optional_frame));
 
+       if (prevent_inline)
+               vfork();
+
        min_frames = 0;
        max_frames = 0;
        for (j = 0; j < __arraycount(optional_frame); ++j) {
@@ -83,24 +90,33 @@
        free(strings);
 }
 
-static void __attribute__((__noinline__))
+static void
 myfunc2(size_t ncalls)
 {
+       if (prevent_inline)
+               vfork();
+
        myfunc3(ncalls);
 }
 
-static void __attribute__((__noinline__))
+static void
 myfunc1(size_t origcalls, size_t ncalls)
 {
+       if (prevent_inline)
+               vfork();
+
        if (ncalls > 1)
                myfunc1(origcalls, ncalls - 1);
        else
                myfunc2(origcalls);
 }
 
-static void __attribute__((__noinline__))
+static void
 myfunc(size_t ncalls)
 {
+       if (prevent_inline)
+               vfork();
+
        myfunc1(ncalls, ncalls);
 }