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[PATCH] tile: fix DWARF bug in clone() for created thread
- From: Chris Metcalf <cmetcalf at tilera dot com>
- To: <libc-ports at sourceware dot org>
- Date: Fri, 14 Dec 2012 10:46:54 -0500
- Subject: [PATCH] tile: fix DWARF bug in clone() for created thread
[David - this is pretty low risk (just adds one DWARF CFI directive),
but also fixes a pretty minor bug. So your call as to whether I should
wait for 2.18 to commit.]
Previously, we would see a bad frame in the gdb backtrace output, e.g.:
(gdb) bt
#0 foo () at foo.c:5
#1 0x000000aaaab68ee8 in start_thread () from /lib/libpthread.so.0
#2 0x000000aaaad01c88 in clone () from /lib/libc.so.6
#3 0x0000000000000000 in ?? ()
With this change the bogus frame #3 is gone and we have the
same output as x86 does for the same program.
2012-12-14 Chris Metcalf <cmetcalf@tilera.com>
* sysdeps/unix/sysv/linux/tile/nptl/clone.S: Fix DWARF info.
diff --git a/ports/sysdeps/unix/sysv/linux/tile/nptl/clone.S b/ports/sysdeps/unix/sysv/linux/tile/nptl/clone.S
index de4fa13..27592cc 100644
--- a/ports/sysdeps/unix/sysv/linux/tile/nptl/clone.S
+++ b/ports/sysdeps/unix/sysv/linux/tile/nptl/clone.S
@@ -160,6 +160,8 @@ ENTRY (__clone)
r32: the user function pointer */
.Lthread_start:
+ cfi_def_cfa_offset (FRAME_SIZE)
+ cfi_undefined (lr)
/* Check and see if we need to reset the PID, which we do if
CLONE_THREAD isn't set, i.e. we're not staying in the thread group.
If CLONE_VM is set, we're doing some kind of thread-like clone,
@@ -167,7 +169,6 @@ ENTRY (__clone)
in getpid(). Otherwise (if CLONE_VM isn't set), it's a
fork-like clone, and we go ahead and write the cached values
from the true system pid (retrieved via __NR_getpid syscall). */
- cfi_def_cfa_offset (FRAME_SIZE)
#ifdef __tilegx__
{
moveli r0, hw1_last(CLONE_VM)
--
1.7.10.3