https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=216711

FIXME: This workaround should be dropped and

glibc/sysdeps/unix/sysv/linux/x86_64/clone.S should get CFI for the child

instead.

2006-12-17  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb/amd64-linux-tdep.c (linux_clone_code): New variable.

	(LINUX_CLONE_LEN): New definition.

	(amd64_linux_clone_running, amd64_linux_outermost_frame): New function.

	(amd64_linux_init_abi): Initialize `outermost_frame_p'.

	* gdb/i386-tdep.c (i386_gdbarch_init): Likewise.

	* gdb/i386-tdep.h (gdbarch_tdep): Add `outermost_frame_p' member.

	* gdb/amd64-tdep.c (amd64_frame_this_id): Call `outermost_frame_p'.

2006-12-17  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb.threads/bt-clone-stop.exp, gdb.threads/bt-clone-stop.c:

	New file.

2007-10-16  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Port to GDB-6.7.

Index: gdb-7.10.90.20160211/gdb/amd64-linux-tdep.c

===================================================================

--- gdb-7.10.90.20160211.orig/gdb/amd64-linux-tdep.c	2016-02-15 23:37:06.936501443 +0100

+++ gdb-7.10.90.20160211/gdb/amd64-linux-tdep.c	2016-02-15 23:37:39.928735691 +0100

@@ -292,6 +292,80 @@

 /* Set the program counter for process PTID to PC.  */

+/* Detect the outermost frame; during unwind of

+   	#5  0x000000305cec68c3 in clone () from /lib64/tls/libc.so.6

+   avoid the additional bogus frame

+   	#6  0x0000000000000000 in ??

+   We compare if the `linux_clone_code' block is _before_ unwound PC.  */

+

+static const unsigned char linux_clone_code[] =

+{

+/* libc/sysdeps/unix/sysv/linux/x86_64/clone.S */

+/* #ifdef RESET_PID */

+/* ... */

+/* 	mov	$SYS_ify(getpid), %eax */

+/* 0xb8, 0x27, 0x00, 0x00, 0x00 */

+/* OR */

+/* 	mov	$SYS_ify(getpid), %rax */

+/* 0x48, 0xc7, 0xc0, 0x27, 0x00, 0x00, 0x00 */

+/* so just: */

+  0x27, 0x00, 0x00, 0x00,

+/* 	syscall */

+  0x0f, 0x05,

+/* 	movl	%eax, %fs:PID */

+  0x64, 0x89, 0x04, 0x25, 0x94, 0x00, 0x00, 0x00,

+/* 	movl	%eax, %fs:TID */

+  0x64, 0x89, 0x04, 0x25, 0x90, 0x00, 0x00, 0x00,

+/* #endif */

+/* 	|* Set up arguments for the function call.  *| */

+/* 	popq	%rax		|* Function to call.  *| */

+  0x58,

+/* 	popq	%rdi		|* Argument.  *| */

+  0x5f,

+/* 	call	*%rax$   */

+  0xff, 0xd0

+};

+

+#define LINUX_CLONE_LEN (sizeof linux_clone_code)

+

+static int

+amd64_linux_clone_running (struct frame_info *this_frame)

+{

+  CORE_ADDR pc = get_frame_pc (this_frame);

+  unsigned char buf[LINUX_CLONE_LEN];

+

+  if (!safe_frame_unwind_memory (this_frame, pc - LINUX_CLONE_LEN, buf,

+				 LINUX_CLONE_LEN))

+    return 0;

+

+  if (memcmp (buf, linux_clone_code, LINUX_CLONE_LEN) != 0)

+    return 0;

+

+  return 1;

+}

+

+static int

+amd64_linux_outermost_frame (struct frame_info *this_frame)

+{

+  CORE_ADDR pc = get_frame_pc (this_frame);

+  const char *name;

+

+  find_pc_partial_function (pc, &name, NULL, NULL);

+

+  /* If we have NAME, we can optimize the search.

+     `clone' NAME still needs to have the code checked as its name may be

+     present in the user code.

+     `__clone' NAME should not be present in the user code but in the initial

+     parts of the `__clone' implementation the unwind still makes sense.

+     More detailed unwinding decision would be too much sensitive to possible

+     subtle changes in specific glibc revisions.  */

+  if (name == NULL || strcmp (name, "clone") == 0

+      || strcmp ("__clone", name) == 0)

+    return (amd64_linux_clone_running (this_frame) != 0);

+

+  return 0;

+}

+

 static void

 amd64_linux_write_pc (struct regcache *regcache, CORE_ADDR pc)

 {

@@ -1800,6 +1874,8 @@

   tdep->xsave_xcr0_offset = I386_LINUX_XSAVE_XCR0_OFFSET;

+  tdep->outermost_frame_p = amd64_linux_outermost_frame;

+

   /* Add the %orig_rax register used for syscall restarting.  */

   set_gdbarch_write_pc (gdbarch, amd64_linux_write_pc);

Index: gdb-7.10.90.20160211/gdb/amd64-tdep.c

===================================================================

--- gdb-7.10.90.20160211.orig/gdb/amd64-tdep.c	2016-02-15 23:37:06.936501443 +0100

+++ gdb-7.10.90.20160211/gdb/amd64-tdep.c	2016-02-15 23:37:39.929735698 +0100

@@ -2494,6 +2494,7 @@

 {

   struct amd64_frame_cache *cache =

     amd64_frame_cache (this_frame, this_cache);

+  struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame));

   if (!cache->base_p)

     return UNWIND_UNAVAILABLE;

@@ -2502,6 +2503,10 @@

   if (cache->base == 0)

     return UNWIND_OUTERMOST;

+  /* Detect OS dependent outermost frames; such as `clone'.  */

+  if (tdep->outermost_frame_p && tdep->outermost_frame_p (this_frame))

+    return UNWIND_OUTERMOST;

+

   return UNWIND_NO_REASON;

 }

@@ -2636,6 +2641,7 @@

 {

   struct amd64_frame_cache *cache =

     amd64_sigtramp_frame_cache (this_frame, this_cache);

+  struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame));

   if (!cache->base_p)

     (*this_id) = frame_id_build_unavailable_stack (get_frame_pc (this_frame));

@@ -2644,6 +2650,11 @@

       /* This marks the outermost frame.  */

       return;

     }

+  else if (tdep->outermost_frame_p && tdep->outermost_frame_p (this_frame))

+    {

+      /* Detect OS dependent outermost frames; such as `clone'.  */

+      return;

+    }

   else

     (*this_id) = frame_id_build (cache->base + 16, get_frame_pc (this_frame));

 }

Index: gdb-7.10.90.20160211/gdb/i386-tdep.c

===================================================================

--- gdb-7.10.90.20160211.orig/gdb/i386-tdep.c	2016-02-15 23:37:06.936501443 +0100

+++ gdb-7.10.90.20160211/gdb/i386-tdep.c	2016-02-15 23:37:39.931735713 +0100

@@ -8305,6 +8305,9 @@

   tdep->xsave_xcr0_offset = -1;

+  /* Unwinding stops on i386 automatically.  */

+  tdep->outermost_frame_p = NULL;

+

   tdep->record_regmap = i386_record_regmap;

   set_gdbarch_long_long_align_bit (gdbarch, 32);

Index: gdb-7.10.90.20160211/gdb/i386-tdep.h

===================================================================

--- gdb-7.10.90.20160211.orig/gdb/i386-tdep.h	2016-02-15 23:37:06.936501443 +0100

+++ gdb-7.10.90.20160211/gdb/i386-tdep.h	2016-02-15 23:37:39.932735720 +0100

@@ -240,6 +240,9 @@

   /* Regsets. */

   const struct regset *fpregset;

+

+  /* Detect OS dependent outermost frames; such as `clone'.  */

+  int (*outermost_frame_p) (struct frame_info *this_frame);

 };

 /* Floating-point registers.  */

Index: gdb-7.10.90.20160211/gdb/testsuite/gdb.threads/bt-clone-stop.c

===================================================================

--- /dev/null	1970-01-01 00:00:00.000000000 +0000

+++ gdb-7.10.90.20160211/gdb/testsuite/gdb.threads/bt-clone-stop.c	2016-02-15 23:37:39.932735720 +0100

@@ -0,0 +1,39 @@

+/* This testcase is part of GDB, the GNU debugger.

+

+   Copyright 2006 Free Software Foundation, Inc.

+

+   This program is free software; you can redistribute it and/or modify

+   it under the terms of the GNU General Public License as published by

+   the Free Software Foundation; either version 2 of the License, or

+   (at your option) any later version.

+

+   This program is distributed in the hope that it will be useful,

+   but WITHOUT ANY WARRANTY; without even the implied warranty of

+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

+   GNU General Public License for more details.

+ 

+   You should have received a copy of the GNU General Public License

+   along with this program; if not, write to the Free Software

+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,

+   MA 02110-1301, USA.  */

+

+

+#include <pthread.h>

+#include <unistd.h>

+#include <assert.h>

+

+

+void *threader (void *arg)

+{

+	assert (0);

+	return NULL;

+}

+

+int main (void)

+{

+	pthread_t t1;

+

+	pthread_create (&t1, NULL, threader, (void *) NULL);

+	for (;;)

+		pause();

+}

Index: gdb-7.10.90.20160211/gdb/testsuite/gdb.threads/bt-clone-stop.exp

===================================================================

--- /dev/null	1970-01-01 00:00:00.000000000 +0000

+++ gdb-7.10.90.20160211/gdb/testsuite/gdb.threads/bt-clone-stop.exp	2016-02-15 23:37:56.197851204 +0100

@@ -0,0 +1,61 @@

+# Copyright 2006 Free Software Foundation, Inc.

+

+# This program is free software; you can redistribute it and/or modify

+# it under the terms of the GNU General Public License as published by

+# the Free Software Foundation; either version 2 of the License, or

+# (at your option) any later version.

+# 

+# This program is distributed in the hope that it will be useful,

+# but WITHOUT ANY WARRANTY; without even the implied warranty of

+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

+# GNU General Public License for more details.

+# 

+# You should have received a copy of the GNU General Public License

+# along with this program; if not, write to the Free Software

+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  

+

+# Backtraced `clone' must not have `PC == 0' as its previous frame.

+

+if $tracelevel then {

+    strace $tracelevel

+}

+

+set testfile bt-clone-stop

+set srcfile ${testfile}.c

+set binfile [standard_output_file ${testfile}]

+if  { [gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {

+    untested "Couldn't compile test program"

+    return -1

+}

+

+# Get things started.

+

+gdb_exit

+gdb_start

+gdb_reinitialize_dir $srcdir/$subdir

+gdb_load ${binfile}

+

+# threader: threader.c:8: threader: Assertion `0' failed.

+# Program received signal SIGABRT, Aborted.

+

+gdb_test "run" \

+     {Thread 2 "bt-clone-stop" received signal SIGABRT.*} \

+     "run"

+

+# Former gdb unwind (the first function is `clone'):

+# #5  0x0000003421ecd62d in ?? () from /lib64/libc.so.6

+# #6  0x0000000000000000 in ?? ()

+# (gdb)

+# Tested `amd64_linux_outermost_frame' functionality should omit the line `#6'.

+# 

+# Two `-re' cases below must be in this order (1st is a subset of the 2nd one).

+# Unhandled case below should not happen and it is fortunately handled by

+# `amd64_linux_outermost_frame' as FAIL (and result `0x0 entry output invalid').

+gdb_test_multiple "bt" "0x0 entry output invalid" {

+    -re "in threader \\(.*\n#\[0-9\]* *0x0* in .*$gdb_prompt $" {

+    	fail "0x0 entry found"

+    }

+    -re "in threader \\(.*$gdb_prompt $" {

+    	pass "0x0 entry not found"

+    }

+}