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-6.8.50.20090802/gdb/amd64-linux-tdep.c

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

--- gdb-6.8.50.20090802.orig/gdb/amd64-linux-tdep.c	2009-07-02 19:25:52.000000000 +0200

+++ gdb-6.8.50.20090802/gdb/amd64-linux-tdep.c	2009-08-03 15:50:08.000000000 +0200

@@ -238,6 +238,80 @@ amd64_linux_register_reggroup_p (struct 

 /* 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);

+  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)

 {

@@ -276,6 +350,8 @@ amd64_linux_init_abi (struct gdbarch_inf

   tdep->sc_reg_offset = amd64_linux_sc_reg_offset;

   tdep->sc_num_regs = ARRAY_SIZE (amd64_linux_sc_reg_offset);

+  tdep->outermost_frame_p = amd64_linux_outermost_frame;

+

   /* GNU/Linux uses SVR4-style shared libraries.  */

   set_solib_svr4_fetch_link_map_offsets

     (gdbarch, svr4_lp64_fetch_link_map_offsets);

Index: gdb-6.8.50.20090802/gdb/amd64-tdep.c

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

--- gdb-6.8.50.20090802.orig/gdb/amd64-tdep.c	2009-07-02 19:25:52.000000000 +0200

+++ gdb-6.8.50.20090802/gdb/amd64-tdep.c	2009-08-03 15:50:08.000000000 +0200

@@ -1736,11 +1736,16 @@ amd64_frame_this_id (struct frame_info *

 {

   struct amd64_frame_cache *cache =

     amd64_frame_cache (this_frame, this_cache);

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

   /* This marks the outermost frame.  */

   if (cache->base == 0)

     return;

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

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

+    return;

+

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

 }

--- gdb-6.8.50.20090811/gdb/i386-tdep.c.orig	2009-08-10 05:02:39.000000000 +0200

+++ gdb-6.8.50.20090811/gdb/i386-tdep.c	2009-08-11 16:33:51.000000000 +0200

@@ -5432,6 +5432,9 @@ i386_gdbarch_init (struct gdbarch_info i

   tdep->sc_pc_offset = -1;

   tdep->sc_sp_offset = -1;

+  /* Unwinding stops on i386 automatically.  */

+  tdep->outermost_frame_p = NULL;

+

   tdep->record_regmap = i386_record_regmap;

   /* The format used for `long double' on almost all i386 targets is

--- gdb-6.8.50.20090811/gdb/i386-tdep.h.orig	2009-08-10 05:02:39.000000000 +0200

+++ gdb-6.8.50.20090811/gdb/i386-tdep.h	2009-08-11 16:34:08.000000000 +0200

@@ -120,6 +120,9 @@ struct gdbarch_tdep

   int (*i386_sysenter_record) (struct regcache *regcache);

   /* Parse syscall args.  */

   int (*i386_syscall_record) (struct regcache *regcache);

+

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

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

 };

 /* Floating-point registers.  */

--- a/gdb/ia64-tdep.c

+++ b/gdb/ia64-tdep.c

@@ -2122,6 +2122,137 @@ static const struct frame_unwind ia64_frame_unwind =

   default_frame_sniffer

 };

+/* Detect the outermost frame; during unwind of

+   	#6  0x2000000000347100 in __clone2 () from /lib/libc.so.6.1

+   avoid the additional bogus frame

+   	#7  0x0000000000000000 in ?? ()  */

+

+static char linux_clone2_code[] =

+{

+/* libc/sysdeps/unix/sysv/linux/ia64/clone2.S */

+  0x09, 0x00, 0x20, 0x12, 0x90, 0x11, 0x00, 0x40,

+  0x28, 0x20, 0x23, 0x00, 0x00, 0x00, 0x04, 0x00,

+/*         st4 [r9]=r8 */

+/*         st4 [r10]=r8 */

+/*         ;; */

+/* #endif */

+  0x02, 0x50, 0x21, 0x40, 0x18, 0x14, 0x90, 0x02,

+  0x90, 0x00, 0x42, 0x00, 0x00, 0x00, 0x04, 0x00,

+/* 1:      ld8 out1=[in0],8        |* Retrieve code pointer.       *| */

+/*         mov out0=in4            |* Pass proper argument to fn *| */

+/*         ;; */

+  0x11, 0x08, 0x00, 0x40, 0x18, 0x10, 0x60, 0x50,

+  0x05, 0x80, 0x03, 0x00, 0x68, 0x00, 0x80, 0x12,

+/*         ld8 gp=[in0]            |* Load function gp.            *| */

+/*         mov b6=out1 */

+/*         br.call.dptk.many rp=b6 |* Call fn(arg) in the child    *| */

+/*         ;; */

+  0x10, 0x48, 0x01, 0x10, 0x00, 0x21, 0x10, 0x00,

+  0xa0, 0x00, 0x42, 0x00, 0x98, 0xdf, 0xf7, 0x5b,

+/*         mov out0=r8             |* Argument to _exit            *| */

+/*         mov gp=loc0 */

+/*         .globl HIDDEN_JUMPTARGET(_exit) */

+/*         br.call.dpnt.many rp=HIDDEN_JUMPTARGET(_exit) */

+/*                                 |* call _exit with result from fn.      *| */

+  0x11, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,

+  0x00, 0x02, 0x00, 0x80, 0x00, 0x00, 0x84, 0x00

+/*         ret                     |* Not reached.         *| */

+};

+

+#define LINUX_CLONE_PRE_SLOTS 3	/* Number of slots before PC.  */

+#define LINUX_CLONE_LEN (sizeof linux_clone2_code)

+

+static int

+ia64_linux_clone2_running (struct frame_info *this_frame)

+{

+  CORE_ADDR pc = get_frame_pc (this_frame);

+  char buf[LINUX_CLONE_LEN];

+  struct minimal_symbol *minsym;

+  long long instr;

+

+  if (!safe_frame_unwind_memory (this_frame, pc - LINUX_CLONE_PRE_SLOTS * 16,

+				 buf, LINUX_CLONE_LEN))

+    return 0;

+

+  if (memcmp (buf, linux_clone2_code, LINUX_CLONE_PRE_SLOTS * 16) != 0)

+    return 0;

+

+  /* Adjust the expected "_exit" address.  */

+  minsym = lookup_minimal_symbol_text ("_exit", NULL);

+  if (minsym == NULL)

+    return 0;

+

+  instr = slotN_contents (&buf[LINUX_CLONE_PRE_SLOTS * 16], 2);

+  instr &= ~(((1L << 20) - 1) << 13);

+  /* Address is relative to the jump instruction slot, not the next one.  */

+  instr |= (((SYMBOL_VALUE_ADDRESS (minsym) - (pc & ~0xfL)) >> 4)

+	    & ((1L << 20) - 1)) << 13;

+  replace_slotN_contents (&buf[LINUX_CLONE_PRE_SLOTS * 16], instr, 2);

+

+  if (memcmp (&buf[LINUX_CLONE_PRE_SLOTS * 16],

+              &linux_clone2_code[LINUX_CLONE_PRE_SLOTS * 16],

+	      LINUX_CLONE_LEN - (LINUX_CLONE_PRE_SLOTS * 16)) != 0)

+    return 0;

+

+  return 1;

+}

+

+static int

+ia64_outermost_frame (struct frame_info *this_frame)

+{

+  CORE_ADDR pc = get_frame_pc (this_frame);

+  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, "clone2") == 0

+      || strcmp ("__clone2", name) == 0)

+    return (ia64_linux_clone2_running (this_frame) != 0);

+

+  return 0;

+}

+

+static void

+ia64_clone2_frame_this_id (struct frame_info *this_frame, void **this_cache,

+			   struct frame_id *this_id)

+{

+  /* Leave the default outermost frame at *THIS_ID.  */

+}

+

+static struct value *

+ia64_clone2_frame_prev_register (struct frame_info *this_frame,

+				 void **this_cache, int regnum)

+{

+  return frame_unwind_got_register (this_frame, regnum, regnum);

+}

+

+static int

+ia64_clone2_frame_sniffer (const struct frame_unwind *self,

+			   struct frame_info *this_frame,

+			   void **this_prologue_cache)

+{

+  if (ia64_outermost_frame (this_frame))

+    return 1;

+

+  return 0;

+}

+

+static const struct frame_unwind ia64_clone2_frame_unwind =

+{

+  NORMAL_FRAME,

+  &ia64_clone2_frame_this_id,

+  &ia64_clone2_frame_prev_register,

+  NULL,

+  &ia64_clone2_frame_sniffer

+};

+

 /* Signal trampolines.  */

 static void

@@ -3824,6 +3955,7 @@ ia64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)

   set_gdbarch_dummy_id (gdbarch, ia64_dummy_id);

   set_gdbarch_unwind_pc (gdbarch, ia64_unwind_pc);

+  frame_unwind_append_unwinder (gdbarch, &ia64_clone2_frame_unwind);

 #ifdef HAVE_LIBUNWIND_IA64_H

   frame_unwind_append_unwinder (gdbarch,

                                 &ia64_libunwind_sigtramp_frame_unwind);

Index: gdb-6.8.50.20090802/gdb/testsuite/gdb.threads/bt-clone-stop.c

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

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

+++ gdb-6.8.50.20090802/gdb/testsuite/gdb.threads/bt-clone-stop.c	2009-08-03 15:50:08.000000000 +0200

@@ -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-6.8.50.20090802/gdb/testsuite/gdb.threads/bt-clone-stop.exp

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

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

+++ gdb-6.8.50.20090802/gdb/testsuite/gdb.threads/bt-clone-stop.exp	2009-08-03 15:50:08.000000000 +0200

@@ -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 ${objdir}/${subdir}/${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" \

+     "Program 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"

+    }

+}