[PATCH v4] Implement $_exitsignal

[PATCH v4] Implement $_exitsignal

[Sergio Durigan Junior]

Hi,

This is the fourth attempt to implement $_exitsignal.  You can read the
last 3 at:

- First attempt:

<http://sourceware.org/ml/gdb-patches/2013-06/msg00352.html>

- Second attempt:

<http://sourceware.org/ml/gdb-patches/2013-06/msg00452.html>

- Third attempt:

<https://sourceware.org/ml/gdb-patches/2013-08/msg00727.html>

The patch has suffered some changes since the third attempt.  In the
code, I basically addressed Pedro's requests of clearing both
$_exit{signal,code} when there is no signal recognized at the corefile,
and (most important) to drop the process of filling $_exitsignal if the
target doesn't provide a way of converting between GDB's internal signal
numbers and the target's.

In the documentation field, I wrote a more extensive section explaining
how to use $_exit{code,signal} together in a GDB script, by making use
of the new convenience function $_isvoid.  This was Doug's request.

I have also obviously added some testcases, but they are unchanged since
the last attempt.

OK to apply?  Thanks,

-- 
Sergio

gdb/
2013-09-17  Sergio Durigan Junior  <sergiodj@redhat.com>

	* NEWS: Mention new convenience variable $_exitsignal.
	* corelow.c (core_open): Set $_exitsignal to the uncaught signal
	which generated the corefile; reset $_exitcode to void.
	* infrun.c (handle_inferior_event): Reset $_exitsignal for
	TARGET_WAITKIND_EXITED; set $_exitsignal and reset $_exitcode for
	TARGET_WAITKIND_SIGNALLED.

gdb/testsuite/
2013-09-17  Sergio Durigan Junior  <sergiodj@redhat.com>

	* gdb.base/corefile.exp: Test whether $_exitsignal is set and
	$_exitcode is void when opening a corefile.
	* gdb.base/exitsignal.exp: New file.
	* gdb.base/segv.c: Likewise.
	* gdb.base/normal.c: Likewise.

gdb/doc/
2013-09-17  Sergio Durigan Junior  <sergiodj@redhat.com>

	* gdb.texinfo (Convenience Variables): Document $_exitsignal.
	Update entry for $_exitcode.

diff --git a/gdb/NEWS b/gdb/NEWS
index af06a21..4c38358 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -87,6 +87,10 @@ show range-stepping
 * The exception-related catchpoints, like "catch throw", now accept a
   regular expression which can be used to filter exceptions by type.
 
+* The new convenience variable $_exitsignal is automatically set to
+  the terminating signal number when the program being debugged dies
+  due to an uncaught signal.
+
 * MI changes
 
   ** The -trace-save MI command can optionally save trace buffer in Common
diff --git a/gdb/corelow.c b/gdb/corelow.c
index 8371b58..9088afb 100644
--- a/gdb/corelow.c
+++ b/gdb/corelow.c
@@ -446,7 +446,22 @@ core_open (char *filename, int from_tty)
 
       printf_filtered (_("Program terminated with signal %s, %s.\n"),
 		       gdb_signal_to_name (sig), gdb_signal_to_string (sig));
+
+      /* Set the value of the internal variable $_exitsignal,
+	 which holds the signal uncaught by the inferior.  */
+      set_internalvar_integer (lookup_internalvar ("_exitsignal"),
+			       siggy);
     }
+  else
+    {
+      /* The inferior did not die because of an uncaught signal,
+	 therefore we must clear $_exitsignal.  */
+      clear_internalvar (lookup_internalvar ("_exitsignal"));
+    }
+
+  /* Clear the $_exitcode internal variable, because there is no way
+     the inferior could have exited and generated a corefile.  */
+  clear_internalvar (lookup_internalvar ("_exitcode"));
 
   /* Fetch all registers from core file.  */
   target_fetch_registers (get_current_regcache (), -1);
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 60d2877..104fe2a 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -9751,8 +9751,64 @@ to match the format in which the data was printed.
 
 @item $_exitcode
 @vindex $_exitcode@r{, convenience variable}
-The variable @code{$_exitcode} is automatically set to the exit code when
-the program being debugged terminates.
+When the program being debugged terminates normally, @value{GDBN}
+automatically sets this variable to the exit code of the program, and
+resets @code{$_exitsignal} to @code{void}.
+
+@item $_exitsignal
+@vindex $_exitsignal@r{, convenience variable}
+When the program being debugged dies due to an uncaught signal,
+@value{GDBN} automatically sets this variable to that signal's number,
+and resets @code{$_exitcode} to @code{void}.
+
+To distinguish between whether the program being debugged has exited
+(i.e., @code{$_exitcode} is not @code{void}) or signalled (i.e.,
+@code{$_exitsignal} is not @code{void}), the convenience function
+@code{$_isvoid} can be used (see @ref{Convenience Funs,, Convenience
+Functions}).  For example, considering the following source code:
+
+@smallexample
+#include <signal.h>
+
+int
+main (int argc, char *argv[])
+@{
+  raise (SIGALRM);
+  return 0;
+@}
+@end smallexample
+
+A valid way of telling whether the program being debugged has exited
+or signalled would be:
+
+@smallexample
+(@value{GDBP}) define has_exited_or_signalled
+Type commands for definition of ``has_exited_or_signalled''.
+End with a line saying just ``end''.
+>if $_isvoid ($_exitsignal)
+ >echo The program has exited\n
+ >else
+ >echo The program has signalled\n
+ >end
+>end
+(@value{GDBP}) run
+Starting program:
+
+Program terminated with signal SIGALRM, Alarm clock.
+The program no longer exists.
+(@value{GDBP}) has_exited_or_signalled
+The program has signalled
+@end smallexample
+
+As can be seen, @value{GDBN} correctly informs that the program being
+debugged has signalled, since it calls @code{raise} and raises a
+@code{SIGALRM} signal.  If the program being debugged had not called
+@code{raise}, then @value{GDBN} would report a normal exit:
+
+@smallexample
+(@value{GDBP}) has_exited_or_signalled
+The program has exited
+@end smallexample
 
 @item $_exception
 The variable @code{$_exception} is set to the exception object being
diff --git a/gdb/infrun.c b/gdb/infrun.c
index 57618ae..e356f8d 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -3432,6 +3432,10 @@ handle_inferior_event (struct execution_control_state *ecs)
 	  set_internalvar_integer (lookup_internalvar ("_exitcode"),
 				   (LONGEST) ecs->ws.value.integer);
 
+	  /* Clear the $_exitsignal internal variable, since if we are
+	     here the inferior has not been terminated by a signal.  */
+	  clear_internalvar (lookup_internalvar ("_exitsignal"));
+
 	  /* Also record this in the inferior itself.  */
 	  current_inferior ()->has_exit_code = 1;
 	  current_inferior ()->exit_code = (LONGEST) ecs->ws.value.integer;
@@ -3439,7 +3443,41 @@ handle_inferior_event (struct execution_control_state *ecs)
 	  print_exited_reason (ecs->ws.value.integer);
 	}
       else
-	print_signal_exited_reason (ecs->ws.value.sig);
+	{
+	  struct regcache *regcache = get_thread_regcache (ecs->ptid);
+	  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+
+	  if (gdbarch_gdb_signal_to_target_p (gdbarch))
+	    {
+	      /* Set the value of the internal variable $_exitsignal,
+		 which holds the signal uncaught by the inferior.  */
+	      set_internalvar_integer (lookup_internalvar ("_exitsignal"),
+				       gdbarch_gdb_signal_to_target (gdbarch,
+							  ecs->ws.value.sig));
+	    }
+	  else
+	    {
+	      static int have_warned_signal_to_target = 0;
+
+	      if (!have_warned_signal_to_target)
+		{
+		  have_warned_signal_to_target = 1;
+		  warning (_("\
+Cannot fill $_exitsignal with the correct signal number."));
+		}
+
+	      /* Clearing the $_exitsignal convenience variable, since
+		 it is not possible to fill it correctly.  */
+	      clear_internalvar (lookup_internalvar ("_exitsignal"));
+	    }
+
+	  print_signal_exited_reason (ecs->ws.value.sig);
+
+	  /* Clear the $_exitcode internal variable, because if the
+	     inferior died with a signal then its return code does not
+	     exist.  */
+	  clear_internalvar (lookup_internalvar ("_exitcode"));
+	}
 
       gdb_flush (gdb_stdout);
       target_mourn_inferior ();
diff --git a/gdb/testsuite/gdb.base/corefile.exp b/gdb/testsuite/gdb.base/corefile.exp
index 24a33a3..77ef954 100644
--- a/gdb/testsuite/gdb.base/corefile.exp
+++ b/gdb/testsuite/gdb.base/corefile.exp
@@ -142,6 +142,16 @@ gdb_test "print coremaker_ro" "\\\$$decimal = 201"
 
 gdb_test "print func2::coremaker_local" "\\\$$decimal = \\{0, 1, 2, 3, 4\\}"
 
+# Test the presence and the correct values of $_exitsignal and
+# $_exitcode variables.  The corefile is generated with a SIGABRT,
+# which is "6" in the Linux kernel.
+
+gdb_test "print \$_exitsignal" " = 6" \
+    "\$_exitsignal prints SIGABRT (6)"
+
+gdb_test "print \$_exitcode" " = void" \
+    "\$_exitcode is void"
+
 # Somehow we better test the ability to read the registers out of the core
 # file correctly.  I don't think the other tests do this.
 
diff --git a/gdb/testsuite/gdb.base/exitsignal.exp b/gdb/testsuite/gdb.base/exitsignal.exp
new file mode 100644
index 0000000..5ab2fee
--- /dev/null
+++ b/gdb/testsuite/gdb.base/exitsignal.exp
@@ -0,0 +1,97 @@
+# Copyright 2013 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 3 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, see <http://www.gnu.org/licenses/>.
+
+# This test checks both $_exitcode and $_exitsignal variables.  The
+# purpose of this checking is to ensure that the variables are
+# mutually exclusive, i.e., that when $_exitsignal is set, $_exitcode
+# is not, and vice-versa.  This mutual exclusion happens because if an
+# inferior exited (either successfuly or not), it certainly was not
+# killed by a signal.  However, if it was killed by an uncaught
+# signal, then there is no way for it to have exited.
+
+standard_testfile segv.c
+
+if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile}] } {
+    return -1
+}
+
+# Run to main
+if { ![runto_main] } {
+    return -1
+}
+
+# Print $_exitsignal.  It should be void now, because nothing
+# happened.
+gdb_test "print \$_exitsignal" " = void" \
+    "\$_exitsignal is void before running"
+
+# Just to guarantee, making sure that $_exitcode is also void.
+gdb_test "print \$_exitcode" " = void" \
+    "\$_exitcode is void before running"
+
+# Trigger SIGSEGV.
+gdb_test "continue" "Program received signal SIGSEGV.*" "trigger SIGSEGV"
+
+# Continue until the end.
+gdb_test "continue" "Program terminated with signal SIGSEGV.*" \
+    "program terminated with SIGSEGV"
+
+# Now, print $_exitsignal again.  It should be 11 (SIGSEGV).
+gdb_test "print \$_exitsignal" " = 11" \
+    "\$_exitsignal is 11 (SIGSEGV) after SIGSEGV."
+
+# And $_exitcode should still be void, since the inferior died because
+# of a signal, and did not return.
+gdb_test "print \$_exitcode" " = void" \
+    "\$_exitcode is still void after SIGSEGV"
+
+# Re-run to main, i.e., restart the executable.
+rerun_to_main
+
+# Print the $_exitsignal again.  Even in this normal scenario, it
+# should still contain the signal triggered in the other run.
+gdb_test "print \$_exitsignal" " = 11" \
+    "\$_exitsignal is 11 (SIGSEGV) after restarting the inferior"
+
+# And, again, print $_exitcode.
+gdb_test "print \$_exitcode" " = void" \
+    "\$_exitcode is still void after restarting the inferior"
+
+# Now we test the behaviour of $_exit{code,signal} during a normal
+# inferior execution.
+standard_testfile normal.c
+
+if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile}] } {
+    return -1
+}
+
+# Checking $_exitsignal and $_exitcode, both should be void before the
+# inferior is executed.
+gdb_test "print \$_exitsignal" " = void" \
+    "\$_exitsignal is void before normal inferior is executed"
+gdb_test "print \$_exitcode" " = void" \
+    "\$_exitcode is void before normal inferior is executed"
+
+# Running until the end.
+gdb_test "run" "\\\[Inferior .* exited normally\\\]" "Run inferior until the end"
+
+# Checking $_exitcode.  It should be 0.
+gdb_test "print \$_exitcode" " = 0" \
+    "\$_exitcode is zero after normal inferior is executed"
+
+# Checking $_exitsignal.  It should still be void, since the inferior
+# has not received any signal.
+gdb_test "print \$_exitsignal" " = void" \
+    "\$_exitsignal is still void after normal inferior is executed"
diff --git a/gdb/testsuite/gdb.base/normal.c b/gdb/testsuite/gdb.base/normal.c
new file mode 100644
index 0000000..4aa7c45
--- /dev/null
+++ b/gdb/testsuite/gdb.base/normal.c
@@ -0,0 +1,24 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2013 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 3 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, see <http://www.gnu.org/licenses/>.  */
+
+/* This test is just a normal return 0.  */
+
+int
+main (int argc, char *argv[])
+{
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.base/segv.c b/gdb/testsuite/gdb.base/segv.c
new file mode 100644
index 0000000..8991f4d
--- /dev/null
+++ b/gdb/testsuite/gdb.base/segv.c
@@ -0,0 +1,29 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2013 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 3 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, see <http://www.gnu.org/licenses/>.  */
+
+/* This test can be used just to generate a SIGSEGV.  */
+
+#include <signal.h>
+
+int
+main (int argc, char *argv[])
+{
+  /* Generating a SIGSEGV.  */
+  raise (SIGSEGV);
+
+  return 0;
+}

Re: [PATCH v4] Implement $_exitsignal

[Eli Zaretskii]

> From: Sergio Durigan Junior <sergiodj@redhat.com>
> Cc: Doug Evans <dje@google.com>, Pedro Alves <palves@redhat.com>
> Date: Tue, 17 Sep 2013 14:50:21 -0300
> 
> +To distinguish between whether the program being debugged has exited
> +(i.e., @code{$_exitcode} is not @code{void}) or signalled (i.e.,
> +@code{$_exitsignal} is not @code{void}), the convenience function
> +@code{$_isvoid} can be used (see @ref{Convenience Funs,, Convenience
> +Functions}).

@pxref would be better here than "see @ref".

Otherwise, the documentation part is OK.

Thanks.

Re: [PATCH v4] Implement $_exitsignal

[Sergio Durigan Junior]

On Tuesday, September 17 2013, Eli Zaretskii wrote:

>> From: Sergio Durigan Junior <sergiodj@redhat.com>
>> Cc: Doug Evans <dje@google.com>, Pedro Alves <palves@redhat.com>
>> Date: Tue, 17 Sep 2013 14:50:21 -0300
>> 
>> +To distinguish between whether the program being debugged has exited
>> +(i.e., @code{$_exitcode} is not @code{void}) or signalled (i.e.,
>> +@code{$_exitsignal} is not @code{void}), the convenience function
>> +@code{$_isvoid} can be used (see @ref{Convenience Funs,, Convenience
>> +Functions}).
>
> @pxref would be better here than "see @ref".
>
> Otherwise, the documentation part is OK.

Thanks, fixed in my tree.

-- 
Sergio

Re: [PATCH v4] Implement $_exitsignal

[Sergio Durigan Junior]

On Tuesday, September 17 2013, I wrote:

> Hi,
>
> This is the fourth attempt to implement $_exitsignal.  You can read the
> last 3 at:
>
> - First attempt:
>
> <http://sourceware.org/ml/gdb-patches/2013-06/msg00352.html>
>
> - Second attempt:
>
> <http://sourceware.org/ml/gdb-patches/2013-06/msg00452.html>
>
> - Third attempt:
>
> <https://sourceware.org/ml/gdb-patches/2013-08/msg00727.html>

Ping.

The documentation part has been already reviewed and approved.

Thanks,

> The patch has suffered some changes since the third attempt.  In the
> code, I basically addressed Pedro's requests of clearing both
> $_exit{signal,code} when there is no signal recognized at the corefile,
> and (most important) to drop the process of filling $_exitsignal if the
> target doesn't provide a way of converting between GDB's internal signal
> numbers and the target's.
>
> In the documentation field, I wrote a more extensive section explaining
> how to use $_exit{code,signal} together in a GDB script, by making use
> of the new convenience function $_isvoid.  This was Doug's request.
>
> I have also obviously added some testcases, but they are unchanged since
> the last attempt.
>
> OK to apply?  Thanks,
>
> -- 
> Sergio
>
> gdb/
> 2013-09-17  Sergio Durigan Junior  <sergiodj@redhat.com>
>
> 	* NEWS: Mention new convenience variable $_exitsignal.
> 	* corelow.c (core_open): Set $_exitsignal to the uncaught signal
> 	which generated the corefile; reset $_exitcode to void.
> 	* infrun.c (handle_inferior_event): Reset $_exitsignal for
> 	TARGET_WAITKIND_EXITED; set $_exitsignal and reset $_exitcode for
> 	TARGET_WAITKIND_SIGNALLED.
>
> gdb/testsuite/
> 2013-09-17  Sergio Durigan Junior  <sergiodj@redhat.com>
>
> 	* gdb.base/corefile.exp: Test whether $_exitsignal is set and
> 	$_exitcode is void when opening a corefile.
> 	* gdb.base/exitsignal.exp: New file.
> 	* gdb.base/segv.c: Likewise.
> 	* gdb.base/normal.c: Likewise.
>
> gdb/doc/
> 2013-09-17  Sergio Durigan Junior  <sergiodj@redhat.com>
>
> 	* gdb.texinfo (Convenience Variables): Document $_exitsignal.
> 	Update entry for $_exitcode.
>
> diff --git a/gdb/NEWS b/gdb/NEWS
> index af06a21..4c38358 100644
> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -87,6 +87,10 @@ show range-stepping
>  * The exception-related catchpoints, like "catch throw", now accept a
>    regular expression which can be used to filter exceptions by type.
>  
> +* The new convenience variable $_exitsignal is automatically set to
> +  the terminating signal number when the program being debugged dies
> +  due to an uncaught signal.
> +
>  * MI changes
>  
>    ** The -trace-save MI command can optionally save trace buffer in Common
> diff --git a/gdb/corelow.c b/gdb/corelow.c
> index 8371b58..9088afb 100644
> --- a/gdb/corelow.c
> +++ b/gdb/corelow.c
> @@ -446,7 +446,22 @@ core_open (char *filename, int from_tty)
>  
>        printf_filtered (_("Program terminated with signal %s, %s.\n"),
>  		       gdb_signal_to_name (sig), gdb_signal_to_string (sig));
> +
> +      /* Set the value of the internal variable $_exitsignal,
> +	 which holds the signal uncaught by the inferior.  */
> +      set_internalvar_integer (lookup_internalvar ("_exitsignal"),
> +			       siggy);
>      }
> +  else
> +    {
> +      /* The inferior did not die because of an uncaught signal,
> +	 therefore we must clear $_exitsignal.  */
> +      clear_internalvar (lookup_internalvar ("_exitsignal"));
> +    }
> +
> +  /* Clear the $_exitcode internal variable, because there is no way
> +     the inferior could have exited and generated a corefile.  */
> +  clear_internalvar (lookup_internalvar ("_exitcode"));
>  
>    /* Fetch all registers from core file.  */
>    target_fetch_registers (get_current_regcache (), -1);
> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index 60d2877..104fe2a 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -9751,8 +9751,64 @@ to match the format in which the data was printed.
>  
>  @item $_exitcode
>  @vindex $_exitcode@r{, convenience variable}
> -The variable @code{$_exitcode} is automatically set to the exit code when
> -the program being debugged terminates.
> +When the program being debugged terminates normally, @value{GDBN}
> +automatically sets this variable to the exit code of the program, and
> +resets @code{$_exitsignal} to @code{void}.
> +
> +@item $_exitsignal
> +@vindex $_exitsignal@r{, convenience variable}
> +When the program being debugged dies due to an uncaught signal,
> +@value{GDBN} automatically sets this variable to that signal's number,
> +and resets @code{$_exitcode} to @code{void}.
> +
> +To distinguish between whether the program being debugged has exited
> +(i.e., @code{$_exitcode} is not @code{void}) or signalled (i.e.,
> +@code{$_exitsignal} is not @code{void}), the convenience function
> +@code{$_isvoid} can be used (see @ref{Convenience Funs,, Convenience
> +Functions}).  For example, considering the following source code:
> +
> +@smallexample
> +#include <signal.h>
> +
> +int
> +main (int argc, char *argv[])
> +@{
> +  raise (SIGALRM);
> +  return 0;
> +@}
> +@end smallexample
> +
> +A valid way of telling whether the program being debugged has exited
> +or signalled would be:
> +
> +@smallexample
> +(@value{GDBP}) define has_exited_or_signalled
> +Type commands for definition of ``has_exited_or_signalled''.
> +End with a line saying just ``end''.
> +>if $_isvoid ($_exitsignal)
> + >echo The program has exited\n
> + >else
> + >echo The program has signalled\n
> + >end
> +>end
> +(@value{GDBP}) run
> +Starting program:
> +
> +Program terminated with signal SIGALRM, Alarm clock.
> +The program no longer exists.
> +(@value{GDBP}) has_exited_or_signalled
> +The program has signalled
> +@end smallexample
> +
> +As can be seen, @value{GDBN} correctly informs that the program being
> +debugged has signalled, since it calls @code{raise} and raises a
> +@code{SIGALRM} signal.  If the program being debugged had not called
> +@code{raise}, then @value{GDBN} would report a normal exit:
> +
> +@smallexample
> +(@value{GDBP}) has_exited_or_signalled
> +The program has exited
> +@end smallexample
>  
>  @item $_exception
>  The variable @code{$_exception} is set to the exception object being
> diff --git a/gdb/infrun.c b/gdb/infrun.c
> index 57618ae..e356f8d 100644
> --- a/gdb/infrun.c
> +++ b/gdb/infrun.c
> @@ -3432,6 +3432,10 @@ handle_inferior_event (struct execution_control_state *ecs)
>  	  set_internalvar_integer (lookup_internalvar ("_exitcode"),
>  				   (LONGEST) ecs->ws.value.integer);
>  
> +	  /* Clear the $_exitsignal internal variable, since if we are
> +	     here the inferior has not been terminated by a signal.  */
> +	  clear_internalvar (lookup_internalvar ("_exitsignal"));
> +
>  	  /* Also record this in the inferior itself.  */
>  	  current_inferior ()->has_exit_code = 1;
>  	  current_inferior ()->exit_code = (LONGEST) ecs->ws.value.integer;
> @@ -3439,7 +3443,41 @@ handle_inferior_event (struct execution_control_state *ecs)
>  	  print_exited_reason (ecs->ws.value.integer);
>  	}
>        else
> -	print_signal_exited_reason (ecs->ws.value.sig);
> +	{
> +	  struct regcache *regcache = get_thread_regcache (ecs->ptid);
> +	  struct gdbarch *gdbarch = get_regcache_arch (regcache);
> +
> +	  if (gdbarch_gdb_signal_to_target_p (gdbarch))
> +	    {
> +	      /* Set the value of the internal variable $_exitsignal,
> +		 which holds the signal uncaught by the inferior.  */
> +	      set_internalvar_integer (lookup_internalvar ("_exitsignal"),
> +				       gdbarch_gdb_signal_to_target (gdbarch,
> +							  ecs->ws.value.sig));
> +	    }
> +	  else
> +	    {
> +	      static int have_warned_signal_to_target = 0;
> +
> +	      if (!have_warned_signal_to_target)
> +		{
> +		  have_warned_signal_to_target = 1;
> +		  warning (_("\
> +Cannot fill $_exitsignal with the correct signal number."));
> +		}
> +
> +	      /* Clearing the $_exitsignal convenience variable, since
> +		 it is not possible to fill it correctly.  */
> +	      clear_internalvar (lookup_internalvar ("_exitsignal"));
> +	    }
> +
> +	  print_signal_exited_reason (ecs->ws.value.sig);
> +
> +	  /* Clear the $_exitcode internal variable, because if the
> +	     inferior died with a signal then its return code does not
> +	     exist.  */
> +	  clear_internalvar (lookup_internalvar ("_exitcode"));
> +	}
>  
>        gdb_flush (gdb_stdout);
>        target_mourn_inferior ();
> diff --git a/gdb/testsuite/gdb.base/corefile.exp b/gdb/testsuite/gdb.base/corefile.exp
> index 24a33a3..77ef954 100644
> --- a/gdb/testsuite/gdb.base/corefile.exp
> +++ b/gdb/testsuite/gdb.base/corefile.exp
> @@ -142,6 +142,16 @@ gdb_test "print coremaker_ro" "\\\$$decimal = 201"
>  
>  gdb_test "print func2::coremaker_local" "\\\$$decimal = \\{0, 1, 2, 3, 4\\}"
>  
> +# Test the presence and the correct values of $_exitsignal and
> +# $_exitcode variables.  The corefile is generated with a SIGABRT,
> +# which is "6" in the Linux kernel.
> +
> +gdb_test "print \$_exitsignal" " = 6" \
> +    "\$_exitsignal prints SIGABRT (6)"
> +
> +gdb_test "print \$_exitcode" " = void" \
> +    "\$_exitcode is void"
> +
>  # Somehow we better test the ability to read the registers out of the core
>  # file correctly.  I don't think the other tests do this.
>  
> diff --git a/gdb/testsuite/gdb.base/exitsignal.exp b/gdb/testsuite/gdb.base/exitsignal.exp
> new file mode 100644
> index 0000000..5ab2fee
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/exitsignal.exp
> @@ -0,0 +1,97 @@
> +# Copyright 2013 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 3 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, see <http://www.gnu.org/licenses/>.
> +
> +# This test checks both $_exitcode and $_exitsignal variables.  The
> +# purpose of this checking is to ensure that the variables are
> +# mutually exclusive, i.e., that when $_exitsignal is set, $_exitcode
> +# is not, and vice-versa.  This mutual exclusion happens because if an
> +# inferior exited (either successfuly or not), it certainly was not
> +# killed by a signal.  However, if it was killed by an uncaught
> +# signal, then there is no way for it to have exited.
> +
> +standard_testfile segv.c
> +
> +if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile}] } {
> +    return -1
> +}
> +
> +# Run to main
> +if { ![runto_main] } {
> +    return -1
> +}
> +
> +# Print $_exitsignal.  It should be void now, because nothing
> +# happened.
> +gdb_test "print \$_exitsignal" " = void" \
> +    "\$_exitsignal is void before running"
> +
> +# Just to guarantee, making sure that $_exitcode is also void.
> +gdb_test "print \$_exitcode" " = void" \
> +    "\$_exitcode is void before running"
> +
> +# Trigger SIGSEGV.
> +gdb_test "continue" "Program received signal SIGSEGV.*" "trigger SIGSEGV"
> +
> +# Continue until the end.
> +gdb_test "continue" "Program terminated with signal SIGSEGV.*" \
> +    "program terminated with SIGSEGV"
> +
> +# Now, print $_exitsignal again.  It should be 11 (SIGSEGV).
> +gdb_test "print \$_exitsignal" " = 11" \
> +    "\$_exitsignal is 11 (SIGSEGV) after SIGSEGV."
> +
> +# And $_exitcode should still be void, since the inferior died because
> +# of a signal, and did not return.
> +gdb_test "print \$_exitcode" " = void" \
> +    "\$_exitcode is still void after SIGSEGV"
> +
> +# Re-run to main, i.e., restart the executable.
> +rerun_to_main
> +
> +# Print the $_exitsignal again.  Even in this normal scenario, it
> +# should still contain the signal triggered in the other run.
> +gdb_test "print \$_exitsignal" " = 11" \
> +    "\$_exitsignal is 11 (SIGSEGV) after restarting the inferior"
> +
> +# And, again, print $_exitcode.
> +gdb_test "print \$_exitcode" " = void" \
> +    "\$_exitcode is still void after restarting the inferior"
> +
> +# Now we test the behaviour of $_exit{code,signal} during a normal
> +# inferior execution.
> +standard_testfile normal.c
> +
> +if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile}] } {
> +    return -1
> +}
> +
> +# Checking $_exitsignal and $_exitcode, both should be void before the
> +# inferior is executed.
> +gdb_test "print \$_exitsignal" " = void" \
> +    "\$_exitsignal is void before normal inferior is executed"
> +gdb_test "print \$_exitcode" " = void" \
> +    "\$_exitcode is void before normal inferior is executed"
> +
> +# Running until the end.
> +gdb_test "run" "\\\[Inferior .* exited normally\\\]" "Run inferior until the end"
> +
> +# Checking $_exitcode.  It should be 0.
> +gdb_test "print \$_exitcode" " = 0" \
> +    "\$_exitcode is zero after normal inferior is executed"
> +
> +# Checking $_exitsignal.  It should still be void, since the inferior
> +# has not received any signal.
> +gdb_test "print \$_exitsignal" " = void" \
> +    "\$_exitsignal is still void after normal inferior is executed"
> diff --git a/gdb/testsuite/gdb.base/normal.c b/gdb/testsuite/gdb.base/normal.c
> new file mode 100644
> index 0000000..4aa7c45
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/normal.c
> @@ -0,0 +1,24 @@
> +/* This testcase is part of GDB, the GNU debugger.
> +
> +   Copyright 2013 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 3 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, see <http://www.gnu.org/licenses/>.  */
> +
> +/* This test is just a normal return 0.  */
> +
> +int
> +main (int argc, char *argv[])
> +{
> +  return 0;
> +}
> diff --git a/gdb/testsuite/gdb.base/segv.c b/gdb/testsuite/gdb.base/segv.c
> new file mode 100644
> index 0000000..8991f4d
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/segv.c
> @@ -0,0 +1,29 @@
> +/* This testcase is part of GDB, the GNU debugger.
> +
> +   Copyright 2013 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 3 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, see <http://www.gnu.org/licenses/>.  */
> +
> +/* This test can be used just to generate a SIGSEGV.  */
> +
> +#include <signal.h>
> +
> +int
> +main (int argc, char *argv[])
> +{
> +  /* Generating a SIGSEGV.  */
> +  raise (SIGSEGV);
> +
> +  return 0;
> +}

-- 
Sergio

Re: [PATCH v4] Implement $_exitsignal

[Sergio Durigan Junior]

On Monday, September 23 2013, I wrote:

> On Tuesday, September 17 2013, I wrote:
>
>> Hi,
>>
>> This is the fourth attempt to implement $_exitsignal.  You can read the
>> last 3 at:
>>
>> - First attempt:
>>
>> <http://sourceware.org/ml/gdb-patches/2013-06/msg00352.html>
>>
>> - Second attempt:
>>
>> <http://sourceware.org/ml/gdb-patches/2013-06/msg00452.html>
>>
>> - Third attempt:
>>
>> <https://sourceware.org/ml/gdb-patches/2013-08/msg00727.html>
>
> Ping.

Ping^2.

> The documentation part has been already reviewed and approved.
>
> Thanks,
>
>> The patch has suffered some changes since the third attempt.  In the
>> code, I basically addressed Pedro's requests of clearing both
>> $_exit{signal,code} when there is no signal recognized at the corefile,
>> and (most important) to drop the process of filling $_exitsignal if the
>> target doesn't provide a way of converting between GDB's internal signal
>> numbers and the target's.
>>
>> In the documentation field, I wrote a more extensive section explaining
>> how to use $_exit{code,signal} together in a GDB script, by making use
>> of the new convenience function $_isvoid.  This was Doug's request.
>>
>> I have also obviously added some testcases, but they are unchanged since
>> the last attempt.
>>
>> OK to apply?  Thanks,
>>
>> -- 
>> Sergio
>>
>> gdb/
>> 2013-09-17  Sergio Durigan Junior  <sergiodj@redhat.com>
>>
>> 	* NEWS: Mention new convenience variable $_exitsignal.
>> 	* corelow.c (core_open): Set $_exitsignal to the uncaught signal
>> 	which generated the corefile; reset $_exitcode to void.
>> 	* infrun.c (handle_inferior_event): Reset $_exitsignal for
>> 	TARGET_WAITKIND_EXITED; set $_exitsignal and reset $_exitcode for
>> 	TARGET_WAITKIND_SIGNALLED.
>>
>> gdb/testsuite/
>> 2013-09-17  Sergio Durigan Junior  <sergiodj@redhat.com>
>>
>> 	* gdb.base/corefile.exp: Test whether $_exitsignal is set and
>> 	$_exitcode is void when opening a corefile.
>> 	* gdb.base/exitsignal.exp: New file.
>> 	* gdb.base/segv.c: Likewise.
>> 	* gdb.base/normal.c: Likewise.
>>
>> gdb/doc/
>> 2013-09-17  Sergio Durigan Junior  <sergiodj@redhat.com>
>>
>> 	* gdb.texinfo (Convenience Variables): Document $_exitsignal.
>> 	Update entry for $_exitcode.
>>
>> diff --git a/gdb/NEWS b/gdb/NEWS
>> index af06a21..4c38358 100644
>> --- a/gdb/NEWS
>> +++ b/gdb/NEWS
>> @@ -87,6 +87,10 @@ show range-stepping
>>  * The exception-related catchpoints, like "catch throw", now accept a
>>    regular expression which can be used to filter exceptions by type.
>>  
>> +* The new convenience variable $_exitsignal is automatically set to
>> +  the terminating signal number when the program being debugged dies
>> +  due to an uncaught signal.
>> +
>>  * MI changes
>>  
>>    ** The -trace-save MI command can optionally save trace buffer in Common
>> diff --git a/gdb/corelow.c b/gdb/corelow.c
>> index 8371b58..9088afb 100644
>> --- a/gdb/corelow.c
>> +++ b/gdb/corelow.c
>> @@ -446,7 +446,22 @@ core_open (char *filename, int from_tty)
>>  
>>        printf_filtered (_("Program terminated with signal %s, %s.\n"),
>>  		       gdb_signal_to_name (sig), gdb_signal_to_string (sig));
>> +
>> +      /* Set the value of the internal variable $_exitsignal,
>> +	 which holds the signal uncaught by the inferior.  */
>> +      set_internalvar_integer (lookup_internalvar ("_exitsignal"),
>> +			       siggy);
>>      }
>> +  else
>> +    {
>> +      /* The inferior did not die because of an uncaught signal,
>> +	 therefore we must clear $_exitsignal.  */
>> +      clear_internalvar (lookup_internalvar ("_exitsignal"));
>> +    }
>> +
>> +  /* Clear the $_exitcode internal variable, because there is no way
>> +     the inferior could have exited and generated a corefile.  */
>> +  clear_internalvar (lookup_internalvar ("_exitcode"));
>>  
>>    /* Fetch all registers from core file.  */
>>    target_fetch_registers (get_current_regcache (), -1);
>> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
>> index 60d2877..104fe2a 100644
>> --- a/gdb/doc/gdb.texinfo
>> +++ b/gdb/doc/gdb.texinfo
>> @@ -9751,8 +9751,64 @@ to match the format in which the data was printed.
>>  
>>  @item $_exitcode
>>  @vindex $_exitcode@r{, convenience variable}
>> -The variable @code{$_exitcode} is automatically set to the exit code when
>> -the program being debugged terminates.
>> +When the program being debugged terminates normally, @value{GDBN}
>> +automatically sets this variable to the exit code of the program, and
>> +resets @code{$_exitsignal} to @code{void}.
>> +
>> +@item $_exitsignal
>> +@vindex $_exitsignal@r{, convenience variable}
>> +When the program being debugged dies due to an uncaught signal,
>> +@value{GDBN} automatically sets this variable to that signal's number,
>> +and resets @code{$_exitcode} to @code{void}.
>> +
>> +To distinguish between whether the program being debugged has exited
>> +(i.e., @code{$_exitcode} is not @code{void}) or signalled (i.e.,
>> +@code{$_exitsignal} is not @code{void}), the convenience function
>> +@code{$_isvoid} can be used (see @ref{Convenience Funs,, Convenience
>> +Functions}).  For example, considering the following source code:
>> +
>> +@smallexample
>> +#include <signal.h>
>> +
>> +int
>> +main (int argc, char *argv[])
>> +@{
>> +  raise (SIGALRM);
>> +  return 0;
>> +@}
>> +@end smallexample
>> +
>> +A valid way of telling whether the program being debugged has exited
>> +or signalled would be:
>> +
>> +@smallexample
>> +(@value{GDBP}) define has_exited_or_signalled
>> +Type commands for definition of ``has_exited_or_signalled''.
>> +End with a line saying just ``end''.
>> +>if $_isvoid ($_exitsignal)
>> + >echo The program has exited\n
>> + >else
>> + >echo The program has signalled\n
>> + >end
>> +>end
>> +(@value{GDBP}) run
>> +Starting program:
>> +
>> +Program terminated with signal SIGALRM, Alarm clock.
>> +The program no longer exists.
>> +(@value{GDBP}) has_exited_or_signalled
>> +The program has signalled
>> +@end smallexample
>> +
>> +As can be seen, @value{GDBN} correctly informs that the program being
>> +debugged has signalled, since it calls @code{raise} and raises a
>> +@code{SIGALRM} signal.  If the program being debugged had not called
>> +@code{raise}, then @value{GDBN} would report a normal exit:
>> +
>> +@smallexample
>> +(@value{GDBP}) has_exited_or_signalled
>> +The program has exited
>> +@end smallexample
>>  
>>  @item $_exception
>>  The variable @code{$_exception} is set to the exception object being
>> diff --git a/gdb/infrun.c b/gdb/infrun.c
>> index 57618ae..e356f8d 100644
>> --- a/gdb/infrun.c
>> +++ b/gdb/infrun.c
>> @@ -3432,6 +3432,10 @@ handle_inferior_event (struct execution_control_state *ecs)
>>  	  set_internalvar_integer (lookup_internalvar ("_exitcode"),
>>  				   (LONGEST) ecs->ws.value.integer);
>>  
>> +	  /* Clear the $_exitsignal internal variable, since if we are
>> +	     here the inferior has not been terminated by a signal.  */
>> +	  clear_internalvar (lookup_internalvar ("_exitsignal"));
>> +
>>  	  /* Also record this in the inferior itself.  */
>>  	  current_inferior ()->has_exit_code = 1;
>>  	  current_inferior ()->exit_code = (LONGEST) ecs->ws.value.integer;
>> @@ -3439,7 +3443,41 @@ handle_inferior_event (struct execution_control_state *ecs)
>>  	  print_exited_reason (ecs->ws.value.integer);
>>  	}
>>        else
>> -	print_signal_exited_reason (ecs->ws.value.sig);
>> +	{
>> +	  struct regcache *regcache = get_thread_regcache (ecs->ptid);
>> +	  struct gdbarch *gdbarch = get_regcache_arch (regcache);
>> +
>> +	  if (gdbarch_gdb_signal_to_target_p (gdbarch))
>> +	    {
>> +	      /* Set the value of the internal variable $_exitsignal,
>> +		 which holds the signal uncaught by the inferior.  */
>> +	      set_internalvar_integer (lookup_internalvar ("_exitsignal"),
>> +				       gdbarch_gdb_signal_to_target (gdbarch,
>> +							  ecs->ws.value.sig));
>> +	    }
>> +	  else
>> +	    {
>> +	      static int have_warned_signal_to_target = 0;
>> +
>> +	      if (!have_warned_signal_to_target)
>> +		{
>> +		  have_warned_signal_to_target = 1;
>> +		  warning (_("\
>> +Cannot fill $_exitsignal with the correct signal number."));
>> +		}
>> +
>> +	      /* Clearing the $_exitsignal convenience variable, since
>> +		 it is not possible to fill it correctly.  */
>> +	      clear_internalvar (lookup_internalvar ("_exitsignal"));
>> +	    }
>> +
>> +	  print_signal_exited_reason (ecs->ws.value.sig);
>> +
>> +	  /* Clear the $_exitcode internal variable, because if the
>> +	     inferior died with a signal then its return code does not
>> +	     exist.  */
>> +	  clear_internalvar (lookup_internalvar ("_exitcode"));
>> +	}
>>  
>>        gdb_flush (gdb_stdout);
>>        target_mourn_inferior ();
>> diff --git a/gdb/testsuite/gdb.base/corefile.exp b/gdb/testsuite/gdb.base/corefile.exp
>> index 24a33a3..77ef954 100644
>> --- a/gdb/testsuite/gdb.base/corefile.exp
>> +++ b/gdb/testsuite/gdb.base/corefile.exp
>> @@ -142,6 +142,16 @@ gdb_test "print coremaker_ro" "\\\$$decimal = 201"
>>  
>>  gdb_test "print func2::coremaker_local" "\\\$$decimal = \\{0, 1, 2, 3, 4\\}"
>>  
>> +# Test the presence and the correct values of $_exitsignal and
>> +# $_exitcode variables.  The corefile is generated with a SIGABRT,
>> +# which is "6" in the Linux kernel.
>> +
>> +gdb_test "print \$_exitsignal" " = 6" \
>> +    "\$_exitsignal prints SIGABRT (6)"
>> +
>> +gdb_test "print \$_exitcode" " = void" \
>> +    "\$_exitcode is void"
>> +
>>  # Somehow we better test the ability to read the registers out of the core
>>  # file correctly.  I don't think the other tests do this.
>>  
>> diff --git a/gdb/testsuite/gdb.base/exitsignal.exp b/gdb/testsuite/gdb.base/exitsignal.exp
>> new file mode 100644
>> index 0000000..5ab2fee
>> --- /dev/null
>> +++ b/gdb/testsuite/gdb.base/exitsignal.exp
>> @@ -0,0 +1,97 @@
>> +# Copyright 2013 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 3 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, see <http://www.gnu.org/licenses/>.
>> +
>> +# This test checks both $_exitcode and $_exitsignal variables.  The
>> +# purpose of this checking is to ensure that the variables are
>> +# mutually exclusive, i.e., that when $_exitsignal is set, $_exitcode
>> +# is not, and vice-versa.  This mutual exclusion happens because if an
>> +# inferior exited (either successfuly or not), it certainly was not
>> +# killed by a signal.  However, if it was killed by an uncaught
>> +# signal, then there is no way for it to have exited.
>> +
>> +standard_testfile segv.c
>> +
>> +if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile}] } {
>> +    return -1
>> +}
>> +
>> +# Run to main
>> +if { ![runto_main] } {
>> +    return -1
>> +}
>> +
>> +# Print $_exitsignal.  It should be void now, because nothing
>> +# happened.
>> +gdb_test "print \$_exitsignal" " = void" \
>> +    "\$_exitsignal is void before running"
>> +
>> +# Just to guarantee, making sure that $_exitcode is also void.
>> +gdb_test "print \$_exitcode" " = void" \
>> +    "\$_exitcode is void before running"
>> +
>> +# Trigger SIGSEGV.
>> +gdb_test "continue" "Program received signal SIGSEGV.*" "trigger SIGSEGV"
>> +
>> +# Continue until the end.
>> +gdb_test "continue" "Program terminated with signal SIGSEGV.*" \
>> +    "program terminated with SIGSEGV"
>> +
>> +# Now, print $_exitsignal again.  It should be 11 (SIGSEGV).
>> +gdb_test "print \$_exitsignal" " = 11" \
>> +    "\$_exitsignal is 11 (SIGSEGV) after SIGSEGV."
>> +
>> +# And $_exitcode should still be void, since the inferior died because
>> +# of a signal, and did not return.
>> +gdb_test "print \$_exitcode" " = void" \
>> +    "\$_exitcode is still void after SIGSEGV"
>> +
>> +# Re-run to main, i.e., restart the executable.
>> +rerun_to_main
>> +
>> +# Print the $_exitsignal again.  Even in this normal scenario, it
>> +# should still contain the signal triggered in the other run.
>> +gdb_test "print \$_exitsignal" " = 11" \
>> +    "\$_exitsignal is 11 (SIGSEGV) after restarting the inferior"
>> +
>> +# And, again, print $_exitcode.
>> +gdb_test "print \$_exitcode" " = void" \
>> +    "\$_exitcode is still void after restarting the inferior"
>> +
>> +# Now we test the behaviour of $_exit{code,signal} during a normal
>> +# inferior execution.
>> +standard_testfile normal.c
>> +
>> +if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile}] } {
>> +    return -1
>> +}
>> +
>> +# Checking $_exitsignal and $_exitcode, both should be void before the
>> +# inferior is executed.
>> +gdb_test "print \$_exitsignal" " = void" \
>> +    "\$_exitsignal is void before normal inferior is executed"
>> +gdb_test "print \$_exitcode" " = void" \
>> +    "\$_exitcode is void before normal inferior is executed"
>> +
>> +# Running until the end.
>> +gdb_test "run" "\\\[Inferior .* exited normally\\\]" "Run inferior until the end"
>> +
>> +# Checking $_exitcode.  It should be 0.
>> +gdb_test "print \$_exitcode" " = 0" \
>> +    "\$_exitcode is zero after normal inferior is executed"
>> +
>> +# Checking $_exitsignal.  It should still be void, since the inferior
>> +# has not received any signal.
>> +gdb_test "print \$_exitsignal" " = void" \
>> +    "\$_exitsignal is still void after normal inferior is executed"
>> diff --git a/gdb/testsuite/gdb.base/normal.c b/gdb/testsuite/gdb.base/normal.c
>> new file mode 100644
>> index 0000000..4aa7c45
>> --- /dev/null
>> +++ b/gdb/testsuite/gdb.base/normal.c
>> @@ -0,0 +1,24 @@
>> +/* This testcase is part of GDB, the GNU debugger.
>> +
>> +   Copyright 2013 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 3 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, see <http://www.gnu.org/licenses/>.  */
>> +
>> +/* This test is just a normal return 0.  */
>> +
>> +int
>> +main (int argc, char *argv[])
>> +{
>> +  return 0;
>> +}
>> diff --git a/gdb/testsuite/gdb.base/segv.c b/gdb/testsuite/gdb.base/segv.c
>> new file mode 100644
>> index 0000000..8991f4d
>> --- /dev/null
>> +++ b/gdb/testsuite/gdb.base/segv.c
>> @@ -0,0 +1,29 @@
>> +/* This testcase is part of GDB, the GNU debugger.
>> +
>> +   Copyright 2013 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 3 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, see <http://www.gnu.org/licenses/>.  */
>> +
>> +/* This test can be used just to generate a SIGSEGV.  */
>> +
>> +#include <signal.h>
>> +
>> +int
>> +main (int argc, char *argv[])
>> +{
>> +  /* Generating a SIGSEGV.  */
>> +  raise (SIGSEGV);
>> +
>> +  return 0;
>> +}
>
> -- 
> Sergio

-- 
Sergio

Re: [PATCH v4] Implement $_exitsignal

[Pedro Alves]

On 09/17/2013 06:50 PM, Sergio Durigan Junior wrote:
> +# Running until the end.
> +gdb_test "run" "\\\[Inferior .* exited normally\\\]" "Run inferior until the end"
> +

I was about to OK the whole patch, but I noticed this: :-/

"run" won't work with "target remote".  Please try the native-gdbserver.exp
board.

As long as there's going to be another round, I think the code
could be simplified.  All that logic that clears the variables:

+      /* The inferior did not die because of an uncaught signal,
+	 therefore we must clear $_exitsignal.  */
+      clear_internalvar (lookup_internalvar ("_exitsignal"));
+    }
+
+  /* Clear the $_exitcode internal variable, because there is no way
+     the inferior could have exited and generated a corefile.  */
+  clear_internalvar (lookup_internalvar ("_exitcode"));

could be replaced by this pattern:

/* Clear these first.  */
clear $_exitsignal;
clear $_exitcode;

if (blah)
   set $_exitsignal;
if (bleh)
   set $_exitcode;

IOW, unconditionally clear both variables first, then set
the one that makes sense.

The same pattern can be done in both corelow.c and infrun.c.

(those clears could be put in a small helper, as they'll
be done in two places).

-- 
Pedro Alves

Re: [PATCH v4] Implement $_exitsignal

[Sergio Durigan Junior]

On Tuesday, October 01 2013, Pedro Alves wrote:

> On 09/17/2013 06:50 PM, Sergio Durigan Junior wrote:
>> +# Running until the end.
>> +gdb_test "run" "\\\[Inferior .* exited normally\\\]" "Run inferior until the end"
>> +
>
> I was about to OK the whole patch, but I noticed this: :-/
>
> "run" won't work with "target remote".  Please try the native-gdbserver.exp
> board.

Ops, thanks for the catch.  I fixed it by checking for is_remote target
and the presence of $use_gdb_stub.  I guess it's enough.  Tested on
native-{,extended-,stdio-}gdbserver.

> As long as there's going to be another round, I think the code
> could be simplified.  All that logic that clears the variables:
>
> +      /* The inferior did not die because of an uncaught signal,
> +	 therefore we must clear $_exitsignal.  */
> +      clear_internalvar (lookup_internalvar ("_exitsignal"));
> +    }
> +
> +  /* Clear the $_exitcode internal variable, because there is no way
> +     the inferior could have exited and generated a corefile.  */
> +  clear_internalvar (lookup_internalvar ("_exitcode"));
>
> could be replaced by this pattern:
>
> /* Clear these first.  */
> clear $_exitsignal;
> clear $_exitcode;
>
> if (blah)
>    set $_exitsignal;
> if (bleh)
>    set $_exitcode;
>
> IOW, unconditionally clear both variables first, then set
> the one that makes sense.
>
> The same pattern can be done in both corelow.c and infrun.c.
>
> (those clears could be put in a small helper, as they'll
> be done in two places).

Done.  I was not sure where to put the declaration of this new helper
function, so I decided for gdb/utils.h.  Not sure it's a good place,
though.  Let me know what you think and I can change it if needed.

Thanks,

-- 
Sergio

gdb/
2013-10-02  Sergio Durigan Junior  <sergiodj@redhat.com>

	* NEWS: Mention new convenience variable $_exitsignal.
	* corelow.c (core_open): Reset exit convenience variables. Set
	$_exitsignal to the uncaught signal which generated the corefile.
	* infrun.c (handle_inferior_event): Reset exit convenience
	variables.  Set $_exitsignal for TARGET_WAITKIND_SIGNALLED.
	(clear_exit_convenience_vars): New function.
	* utils.h (clear_exit_convenience_vars): New prototype.

gdb/testsuite/
2013-10-02  Sergio Durigan Junior  <sergiodj@redhat.com>

	* gdb.base/corefile.exp: Test whether $_exitsignal is set and
	$_exitcode is void when opening a corefile.
	* gdb.base/exitsignal.exp: New file.
	* gdb.base/segv.c: Likewise.
	* gdb.base/normal.c: Likewise.

gdb/doc/
2013-10-02  Sergio Durigan Junior  <sergiodj@redhat.com>

	* gdb.texinfo (Convenience Variables): Document $_exitsignal.
	Update entry for $_exitcode.

diff --git a/gdb/NEWS b/gdb/NEWS
index 5a9f8db..90311c2 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -119,6 +119,10 @@ show range-stepping
 * The exception-related catchpoints, like "catch throw", now accept a
   regular expression which can be used to filter exceptions by type.
 
+* The new convenience variable $_exitsignal is automatically set to
+  the terminating signal number when the program being debugged dies
+  due to an uncaught signal.
+
 * MI changes
 
   ** The -trace-save MI command can optionally save trace buffer in Common
diff --git a/gdb/corelow.c b/gdb/corelow.c
index 7a5aaab..d1e7f6a 100644
--- a/gdb/corelow.c
+++ b/gdb/corelow.c
@@ -429,6 +429,9 @@ core_open (char *filename, int from_tty)
   if (p)
     printf_filtered (_("Core was generated by `%s'.\n"), p);
 
+  /* Clearing any previous state of convenience variables.  */
+  clear_exit_convenience_vars ();
+
   siggy = bfd_core_file_failing_signal (core_bfd);
   if (siggy > 0)
     {
@@ -446,6 +449,11 @@ core_open (char *filename, int from_tty)
 
       printf_filtered (_("Program terminated with signal %s, %s.\n"),
 		       gdb_signal_to_name (sig), gdb_signal_to_string (sig));
+
+      /* Set the value of the internal variable $_exitsignal,
+	 which holds the signal uncaught by the inferior.  */
+      set_internalvar_integer (lookup_internalvar ("_exitsignal"),
+			       siggy);
     }
 
   /* Fetch all registers from core file.  */
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index cf6f7d3..63092eb 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -9751,8 +9751,64 @@ to match the format in which the data was printed.
 
 @item $_exitcode
 @vindex $_exitcode@r{, convenience variable}
-The variable @code{$_exitcode} is automatically set to the exit code when
-the program being debugged terminates.
+When the program being debugged terminates normally, @value{GDBN}
+automatically sets this variable to the exit code of the program, and
+resets @code{$_exitsignal} to @code{void}.
+
+@item $_exitsignal
+@vindex $_exitsignal@r{, convenience variable}
+When the program being debugged dies due to an uncaught signal,
+@value{GDBN} automatically sets this variable to that signal's number,
+and resets @code{$_exitcode} to @code{void}.
+
+To distinguish between whether the program being debugged has exited
+(i.e., @code{$_exitcode} is not @code{void}) or signalled (i.e.,
+@code{$_exitsignal} is not @code{void}), the convenience function
+@code{$_isvoid} can be used (@pxref{Convenience Funs,, Convenience
+Functions}).  For example, considering the following source code:
+
+@smallexample
+#include <signal.h>
+
+int
+main (int argc, char *argv[])
+@{
+  raise (SIGALRM);
+  return 0;
+@}
+@end smallexample
+
+A valid way of telling whether the program being debugged has exited
+or signalled would be:
+
+@smallexample
+(@value{GDBP}) define has_exited_or_signalled
+Type commands for definition of ``has_exited_or_signalled''.
+End with a line saying just ``end''.
+>if $_isvoid ($_exitsignal)
+ >echo The program has exited\n
+ >else
+ >echo The program has signalled\n
+ >end
+>end
+(@value{GDBP}) run
+Starting program:
+
+Program terminated with signal SIGALRM, Alarm clock.
+The program no longer exists.
+(@value{GDBP}) has_exited_or_signalled
+The program has signalled
+@end smallexample
+
+As can be seen, @value{GDBN} correctly informs that the program being
+debugged has signalled, since it calls @code{raise} and raises a
+@code{SIGALRM} signal.  If the program being debugged had not called
+@code{raise}, then @value{GDBN} would report a normal exit:
+
+@smallexample
+(@value{GDBP}) has_exited_or_signalled
+The program has exited
+@end smallexample
 
 @item $_exception
 The variable @code{$_exception} is set to the exception object being
diff --git a/gdb/infrun.c b/gdb/infrun.c
index db0ad8d..e5056c5 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -3426,6 +3426,9 @@ handle_inferior_event (struct execution_control_state *ecs)
       handle_vfork_child_exec_or_exit (0);
       target_terminal_ours ();	/* Must do this before mourn anyway.  */
 
+      /* Clearing any previous state of convenience variables.  */
+      clear_exit_convenience_vars ();
+
       if (ecs->ws.kind == TARGET_WAITKIND_EXITED)
 	{
 	  /* Record the exit code in the convenience variable $_exitcode, so
@@ -3440,7 +3443,38 @@ handle_inferior_event (struct execution_control_state *ecs)
 	  print_exited_reason (ecs->ws.value.integer);
 	}
       else
-	print_signal_exited_reason (ecs->ws.value.sig);
+	{
+	  struct regcache *regcache = get_thread_regcache (ecs->ptid);
+	  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+
+	  if (gdbarch_gdb_signal_to_target_p (gdbarch))
+	    {
+	      /* Set the value of the internal variable $_exitsignal,
+		 which holds the signal uncaught by the inferior.  */
+	      set_internalvar_integer (lookup_internalvar ("_exitsignal"),
+				       gdbarch_gdb_signal_to_target (gdbarch,
+							  ecs->ws.value.sig));
+	    }
+	  else
+	    {
+	      static int have_warned_signal_to_target = 0;
+
+	      /* We don't have access to the target's method used for
+		 converting between signal numbers (GDB's internal
+		 representation <-> target's representation).
+		 Therefore, we cannot do a good job at displaying this
+		 information to the user.  It's better to just warn
+		 her about it, and give up.  */
+	      if (!have_warned_signal_to_target)
+		{
+		  have_warned_signal_to_target = 1;
+		  warning (_("\
+Cannot fill $_exitsignal with the correct signal number."));
+		}
+	    }
+
+	  print_signal_exited_reason (ecs->ws.value.sig);
+	}
 
       gdb_flush (gdb_stdout);
       target_mourn_inferior ();
@@ -7061,6 +7095,15 @@ save_inferior_ptid (void)
   *saved_ptid_ptr = inferior_ptid;
   return make_cleanup (restore_inferior_ptid, saved_ptid_ptr);
 }
+
+/* See comment at utils.h.  */
+
+void
+clear_exit_convenience_vars (void)
+{
+  clear_internalvar (lookup_internalvar ("_exitsignal"));
+  clear_internalvar (lookup_internalvar ("_exitcode"));
+}
 \f
 
 /* User interface for reverse debugging:
diff --git a/gdb/testsuite/gdb.base/corefile.exp b/gdb/testsuite/gdb.base/corefile.exp
index 04ae969..72c7a4a 100644
--- a/gdb/testsuite/gdb.base/corefile.exp
+++ b/gdb/testsuite/gdb.base/corefile.exp
@@ -142,6 +142,16 @@ gdb_test "print coremaker_ro" "\\\$$decimal = 201"
 
 gdb_test "print func2::coremaker_local" "\\\$$decimal = \\{0, 1, 2, 3, 4\\}"
 
+# Test the presence and the correct values of $_exitsignal and
+# $_exitcode variables.  The corefile is generated with a SIGABRT,
+# which is "6" in the Linux kernel.
+
+gdb_test "print \$_exitsignal" " = 6" \
+    "\$_exitsignal prints SIGABRT (6)"
+
+gdb_test "print \$_exitcode" " = void" \
+    "\$_exitcode is void"
+
 # Somehow we better test the ability to read the registers out of the core
 # file correctly.  I don't think the other tests do this.
 
diff --git a/gdb/testsuite/gdb.base/exitsignal.exp b/gdb/testsuite/gdb.base/exitsignal.exp
new file mode 100644
index 0000000..3678fd8
--- /dev/null
+++ b/gdb/testsuite/gdb.base/exitsignal.exp
@@ -0,0 +1,102 @@
+# Copyright 2013 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 3 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, see <http://www.gnu.org/licenses/>.
+
+# This test checks both $_exitcode and $_exitsignal variables.  The
+# purpose of this checking is to ensure that the variables are
+# mutually exclusive, i.e., that when $_exitsignal is set, $_exitcode
+# is not, and vice-versa.  This mutual exclusion happens because if an
+# inferior exited (either successfuly or not), it certainly was not
+# killed by a signal.  However, if it was killed by an uncaught
+# signal, then there is no way for it to have exited.
+
+standard_testfile segv.c
+
+if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile}] } {
+    return -1
+}
+
+# Run to main
+if { ![runto_main] } {
+    return -1
+}
+
+# Print $_exitsignal.  It should be void now, because nothing
+# happened.
+gdb_test "print \$_exitsignal" " = void" \
+    "\$_exitsignal is void before running"
+
+# Just to guarantee, making sure that $_exitcode is also void.
+gdb_test "print \$_exitcode" " = void" \
+    "\$_exitcode is void before running"
+
+# Trigger SIGSEGV.
+gdb_test "continue" "Program received signal SIGSEGV.*" "trigger SIGSEGV"
+
+# Continue until the end.
+gdb_test "continue" "Program terminated with signal SIGSEGV.*" \
+    "program terminated with SIGSEGV"
+
+# Now, print $_exitsignal again.  It should be 11 (SIGSEGV).
+gdb_test "print \$_exitsignal" " = 11" \
+    "\$_exitsignal is 11 (SIGSEGV) after SIGSEGV."
+
+# And $_exitcode should still be void, since the inferior died because
+# of a signal, and did not return.
+gdb_test "print \$_exitcode" " = void" \
+    "\$_exitcode is still void after SIGSEGV"
+
+# Re-run to main, i.e., restart the executable.
+rerun_to_main
+
+# Print the $_exitsignal again.  Even in this normal scenario, it
+# should still contain the signal triggered in the other run.
+gdb_test "print \$_exitsignal" " = 11" \
+    "\$_exitsignal is 11 (SIGSEGV) after restarting the inferior"
+
+# And, again, print $_exitcode.
+gdb_test "print \$_exitcode" " = void" \
+    "\$_exitcode is still void after restarting the inferior"
+
+# 
+if { [is_remote target] && [target_info exists use_gdb_stub] } then {
+    continue
+}
+
+# Now we test the behaviour of $_exit{code,signal} during a normal
+# inferior execution.
+standard_testfile normal.c
+
+if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile}] } {
+    return -1
+}
+
+# Checking $_exitsignal and $_exitcode, both should be void before the
+# inferior is executed.
+gdb_test "print \$_exitsignal" " = void" \
+    "\$_exitsignal is void before normal inferior is executed"
+gdb_test "print \$_exitcode" " = void" \
+    "\$_exitcode is void before normal inferior is executed"
+
+# Running until the end.
+gdb_test "run" "\\\[Inferior .* exited normally\\\]" "Run inferior until the end"
+
+# Checking $_exitcode.  It should be 0.
+gdb_test "print \$_exitcode" " = 0" \
+    "\$_exitcode is zero after normal inferior is executed"
+
+# Checking $_exitsignal.  It should still be void, since the inferior
+# has not received any signal.
+gdb_test "print \$_exitsignal" " = void" \
+    "\$_exitsignal is still void after normal inferior is executed"
diff --git a/gdb/testsuite/gdb.base/normal.c b/gdb/testsuite/gdb.base/normal.c
new file mode 100644
index 0000000..4aa7c45
--- /dev/null
+++ b/gdb/testsuite/gdb.base/normal.c
@@ -0,0 +1,24 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2013 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 3 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, see <http://www.gnu.org/licenses/>.  */
+
+/* This test is just a normal return 0.  */
+
+int
+main (int argc, char *argv[])
+{
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.base/segv.c b/gdb/testsuite/gdb.base/segv.c
new file mode 100644
index 0000000..8991f4d
--- /dev/null
+++ b/gdb/testsuite/gdb.base/segv.c
@@ -0,0 +1,29 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2013 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 3 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, see <http://www.gnu.org/licenses/>.  */
+
+/* This test can be used just to generate a SIGSEGV.  */
+
+#include <signal.h>
+
+int
+main (int argc, char *argv[])
+{
+  /* Generating a SIGSEGV.  */
+  raise (SIGSEGV);
+
+  return 0;
+}
diff --git a/gdb/utils.h b/gdb/utils.h
index 3492f09..74d886f 100644
--- a/gdb/utils.h
+++ b/gdb/utils.h
@@ -331,6 +331,12 @@ extern void vwarning (const char *, va_list args) ATTRIBUTE_PRINTF (1, 0);
 void *hashtab_obstack_allocate (void *data, size_t size, size_t count);
 void dummy_obstack_deallocate (void *object, void *data);
 
+/* This function clears the convenience variables associated with the
+   exit of the inferior.  Currently, those variables are $_exitcode
+   and $_exitsignal.  */
+
+extern void clear_exit_convenience_vars (void);
+
 #ifdef HAVE_WAITPID
 extern pid_t wait_to_die_with_timeout (pid_t pid, int *status, int timeout);
 #endif

Re: [PATCH v4] Implement $_exitsignal

[Pedro Alves]

On 10/03/2013 06:48 AM, Sergio Durigan Junior wrote:
> On Tuesday, October 01 2013, Pedro Alves wrote:
>> "run" won't work with "target remote".  Please try the native-gdbserver.exp
>> board.
> 
> Ops, thanks for the catch.  I fixed it by checking for is_remote target
> and the presence of $use_gdb_stub.  I guess it's enough.  Tested on
> native-{,extended-,stdio-}gdbserver.

Sorry for not being clearer, but what I had in mind was the complete
opposite -- what would it take to make those tests _also_ run against
"target remote".  Is "run" special at all here?  The test just seems
to want to run the program to exit.  runto_main + gdb_continue_to_end
should work just as well for that.


>> (those clears could be put in a small helper, as they'll
>> be done in two places).
> 
> Done.  I was not sure where to put the declaration of this new helper
> function, so I decided for gdb/utils.h.  Not sure it's a good place,
> though.  Let me know what you think and I can change it if needed.

Not a good place.  utils.h == kitchen sink.  ;-)

infrun.c things are declared in inferior.h currently.



> +/* This function clears the convenience variables associated with the
> +   exit of the inferior.  Currently, those variables are $_exitcode
> +   and $_exitsignal.  */
> +
> +extern void clear_exit_convenience_vars (void);

It's more common to avoid the redundant "This function".  E.g.,:

/* Clear the convenience variables associated with the exit of the
   inferior.  Currently, those variables are $_exitcode and
   $_exitsignal.  */



> +	  else
> +	    {
> +	      static int have_warned_signal_to_target = 0;
> +
> +	      /* We don't have access to the target's method used for
> +		 converting between signal numbers (GDB's internal
> +		 representation <-> target's representation).
> +		 Therefore, we cannot do a good job at displaying this
> +		 information to the user.  It's better to just warn
> +		 her about it, and give up.  */
> +	      if (!have_warned_signal_to_target)
> +		{
> +		  have_warned_signal_to_target = 1;
> +		  warning (_("\
> +Cannot fill $_exitsignal with the correct signal number."));
> +		}

I thing this warning will be a nuisance for most targets.
_Everyone_ not debugging Linux will see this.  But, there's really
nothing a regular user or integrator can do to fix this, and I don't
believe this is such an important feature that warrants printing
this on most runs.  I'd rather see this downgraded to a
complaint() or debug output.


I recalled that signal tests should be skipped if
[target_info exists gdb,nosignals].


Also:

$ git am /tmp/mbox
Applying: Implement $_exitsignal
/home/pedro/gdb/mygit/src/.git/rebase-apply/patch:281: trailing whitespace.
#
warning: 1 line adds whitespace errors.

-- 
Pedro Alves

Re: [PATCH v4] Implement $_exitsignal

[Sergio Durigan Junior]

On Thursday, October 03 2013, Pedro Alves wrote:

> On 10/03/2013 06:48 AM, Sergio Durigan Junior wrote:
>> On Tuesday, October 01 2013, Pedro Alves wrote:
>>> "run" won't work with "target remote".  Please try the native-gdbserver.exp
>>> board.
>> 
>> Ops, thanks for the catch.  I fixed it by checking for is_remote target
>> and the presence of $use_gdb_stub.  I guess it's enough.  Tested on
>> native-{,extended-,stdio-}gdbserver.
>
> Sorry for not being clearer, but what I had in mind was the complete
> opposite -- what would it take to make those tests _also_ run against
> "target remote".  Is "run" special at all here?  The test just seems
> to want to run the program to exit.  runto_main + gdb_continue_to_end
> should work just as well for that.

Ops, got it.  And yes, runto_main + gdb_continue_to_end works OK.
Thanks for the tip.

>>> (those clears could be put in a small helper, as they'll
>>> be done in two places).
>> 
>> Done.  I was not sure where to put the declaration of this new helper
>> function, so I decided for gdb/utils.h.  Not sure it's a good place,
>> though.  Let me know what you think and I can change it if needed.
>
> Not a good place.  utils.h == kitchen sink.  ;-)
>
> infrun.c things are declared in inferior.h currently.

I was not sure about utils.h or inferior.h...  Anyway, fixed.

>> +/* This function clears the convenience variables associated with the
>> +   exit of the inferior.  Currently, those variables are $_exitcode
>> +   and $_exitsignal.  */
>> +
>> +extern void clear_exit_convenience_vars (void);
>
> It's more common to avoid the redundant "This function".  E.g.,:
>
> /* Clear the convenience variables associated with the exit of the
>    inferior.  Currently, those variables are $_exitcode and
>    $_exitsignal.  */

Fixed.

>> +	  else
>> +	    {
>> +	      static int have_warned_signal_to_target = 0;
>> +
>> +	      /* We don't have access to the target's method used for
>> +		 converting between signal numbers (GDB's internal
>> +		 representation <-> target's representation).
>> +		 Therefore, we cannot do a good job at displaying this
>> +		 information to the user.  It's better to just warn
>> +		 her about it, and give up.  */
>> +	      if (!have_warned_signal_to_target)
>> +		{
>> +		  have_warned_signal_to_target = 1;
>> +		  warning (_("\
>> +Cannot fill $_exitsignal with the correct signal number."));
>> +		}
>
> I thing this warning will be a nuisance for most targets.
> _Everyone_ not debugging Linux will see this.  But, there's really
> nothing a regular user or integrator can do to fix this, and I don't
> believe this is such an important feature that warrants printing
> this on most runs.  I'd rather see this downgraded to a
> complaint() or debug output.

I've chosen to print when debug_infrun is set.

> I recalled that signal tests should be skipped if
> [target_info exists gdb,nosignals].

Fixed.

> Also:
>
> $ git am /tmp/mbox
> Applying: Implement $_exitsignal
> /home/pedro/gdb/mygit/src/.git/rebase-apply/patch:281: trailing whitespace.
> #
> warning: 1 line adds whitespace errors.

Strange.  Anyway, please look at this new version.  Thanks.

-- 
Sergio

gdb/
2013-10-02  Sergio Durigan Junior  <sergiodj@redhat.com>

	* NEWS: Mention new convenience variable $_exitsignal.
	* corelow.c (core_open): Reset exit convenience variables. Set
	$_exitsignal to the uncaught signal which generated the corefile.
	* infrun.c (handle_inferior_event): Reset exit convenience
	variables.  Set $_exitsignal for TARGET_WAITKIND_SIGNALLED.
	(clear_exit_convenience_vars): New function.
	* utils.h (clear_exit_convenience_vars): New prototype.

gdb/testsuite/
2013-10-02  Sergio Durigan Junior  <sergiodj@redhat.com>

	* gdb.base/corefile.exp: Test whether $_exitsignal is set and
	$_exitcode is void when opening a corefile.
	* gdb.base/exitsignal.exp: New file.
	* gdb.base/segv.c: Likewise.
	* gdb.base/normal.c: Likewise.

gdb/doc/
2013-10-02  Sergio Durigan Junior  <sergiodj@redhat.com>

	* gdb.texinfo (Convenience Variables): Document $_exitsignal.
	Update entry for $_exitcode.

diff --git a/gdb/NEWS b/gdb/NEWS
index 5a9f8db..90311c2 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -119,6 +119,10 @@ show range-stepping
 * The exception-related catchpoints, like "catch throw", now accept a
   regular expression which can be used to filter exceptions by type.
 
+* The new convenience variable $_exitsignal is automatically set to
+  the terminating signal number when the program being debugged dies
+  due to an uncaught signal.
+
 * MI changes
 
   ** The -trace-save MI command can optionally save trace buffer in Common
diff --git a/gdb/corelow.c b/gdb/corelow.c
index 7a5aaab..d1e7f6a 100644
--- a/gdb/corelow.c
+++ b/gdb/corelow.c
@@ -429,6 +429,9 @@ core_open (char *filename, int from_tty)
   if (p)
     printf_filtered (_("Core was generated by `%s'.\n"), p);
 
+  /* Clearing any previous state of convenience variables.  */
+  clear_exit_convenience_vars ();
+
   siggy = bfd_core_file_failing_signal (core_bfd);
   if (siggy > 0)
     {
@@ -446,6 +449,11 @@ core_open (char *filename, int from_tty)
 
       printf_filtered (_("Program terminated with signal %s, %s.\n"),
 		       gdb_signal_to_name (sig), gdb_signal_to_string (sig));
+
+      /* Set the value of the internal variable $_exitsignal,
+	 which holds the signal uncaught by the inferior.  */
+      set_internalvar_integer (lookup_internalvar ("_exitsignal"),
+			       siggy);
     }
 
   /* Fetch all registers from core file.  */
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index cf6f7d3..63092eb 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -9751,8 +9751,64 @@ to match the format in which the data was printed.
 
 @item $_exitcode
 @vindex $_exitcode@r{, convenience variable}
-The variable @code{$_exitcode} is automatically set to the exit code when
-the program being debugged terminates.
+When the program being debugged terminates normally, @value{GDBN}
+automatically sets this variable to the exit code of the program, and
+resets @code{$_exitsignal} to @code{void}.
+
+@item $_exitsignal
+@vindex $_exitsignal@r{, convenience variable}
+When the program being debugged dies due to an uncaught signal,
+@value{GDBN} automatically sets this variable to that signal's number,
+and resets @code{$_exitcode} to @code{void}.
+
+To distinguish between whether the program being debugged has exited
+(i.e., @code{$_exitcode} is not @code{void}) or signalled (i.e.,
+@code{$_exitsignal} is not @code{void}), the convenience function
+@code{$_isvoid} can be used (@pxref{Convenience Funs,, Convenience
+Functions}).  For example, considering the following source code:
+
+@smallexample
+#include <signal.h>
+
+int
+main (int argc, char *argv[])
+@{
+  raise (SIGALRM);
+  return 0;
+@}
+@end smallexample
+
+A valid way of telling whether the program being debugged has exited
+or signalled would be:
+
+@smallexample
+(@value{GDBP}) define has_exited_or_signalled
+Type commands for definition of ``has_exited_or_signalled''.
+End with a line saying just ``end''.
+>if $_isvoid ($_exitsignal)
+ >echo The program has exited\n
+ >else
+ >echo The program has signalled\n
+ >end
+>end
+(@value{GDBP}) run
+Starting program:
+
+Program terminated with signal SIGALRM, Alarm clock.
+The program no longer exists.
+(@value{GDBP}) has_exited_or_signalled
+The program has signalled
+@end smallexample
+
+As can be seen, @value{GDBN} correctly informs that the program being
+debugged has signalled, since it calls @code{raise} and raises a
+@code{SIGALRM} signal.  If the program being debugged had not called
+@code{raise}, then @value{GDBN} would report a normal exit:
+
+@smallexample
+(@value{GDBP}) has_exited_or_signalled
+The program has exited
+@end smallexample
 
 @item $_exception
 The variable @code{$_exception} is set to the exception object being
diff --git a/gdb/inferior.h b/gdb/inferior.h
index 922a0f2..fa8a5d3 100644
--- a/gdb/inferior.h
+++ b/gdb/inferior.h
@@ -639,4 +639,10 @@ extern void signal_catch_update (const unsigned int *);
 
 enum gdb_signal gdb_signal_from_command (int num);
 
+/* Clear the convenience variables associated with the exit of the
+   inferior.  Currently, those variables are $_exitcode and
+   $_exitsignal.  */
+
+extern void clear_exit_convenience_vars (void);
+
 #endif /* !defined (INFERIOR_H) */
diff --git a/gdb/infrun.c b/gdb/infrun.c
index db0ad8d..3c1294d 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -3426,6 +3426,9 @@ handle_inferior_event (struct execution_control_state *ecs)
       handle_vfork_child_exec_or_exit (0);
       target_terminal_ours ();	/* Must do this before mourn anyway.  */
 
+      /* Clearing any previous state of convenience variables.  */
+      clear_exit_convenience_vars ();
+
       if (ecs->ws.kind == TARGET_WAITKIND_EXITED)
 	{
 	  /* Record the exit code in the convenience variable $_exitcode, so
@@ -3440,7 +3443,34 @@ handle_inferior_event (struct execution_control_state *ecs)
 	  print_exited_reason (ecs->ws.value.integer);
 	}
       else
-	print_signal_exited_reason (ecs->ws.value.sig);
+	{
+	  struct regcache *regcache = get_thread_regcache (ecs->ptid);
+	  struct gdbarch *gdbarch = get_regcache_arch (regcache);
+
+	  if (gdbarch_gdb_signal_to_target_p (gdbarch))
+	    {
+	      /* Set the value of the internal variable $_exitsignal,
+		 which holds the signal uncaught by the inferior.  */
+	      set_internalvar_integer (lookup_internalvar ("_exitsignal"),
+				       gdbarch_gdb_signal_to_target (gdbarch,
+							  ecs->ws.value.sig));
+	    }
+	  else
+	    {
+	      /* We don't have access to the target's method used for
+		 converting between signal numbers (GDB's internal
+		 representation <-> target's representation).
+		 Therefore, we cannot do a good job at displaying this
+		 information to the user.  It's better to just warn
+		 her about it (if infrun debugging is enabled), and
+		 give up.  */
+	      if (debug_infrun)
+		fprintf_filtered (gdb_stdlog, _("\
+Cannot fill $_exitsignal with the correct signal number.\n"));
+	    }
+
+	  print_signal_exited_reason (ecs->ws.value.sig);
+	}
 
       gdb_flush (gdb_stdout);
       target_mourn_inferior ();
@@ -7061,6 +7091,15 @@ save_inferior_ptid (void)
   *saved_ptid_ptr = inferior_ptid;
   return make_cleanup (restore_inferior_ptid, saved_ptid_ptr);
 }
+
+/* See comment at utils.h.  */
+
+void
+clear_exit_convenience_vars (void)
+{
+  clear_internalvar (lookup_internalvar ("_exitsignal"));
+  clear_internalvar (lookup_internalvar ("_exitcode"));
+}
 \f
 
 /* User interface for reverse debugging:
diff --git a/gdb/testsuite/gdb.base/corefile.exp b/gdb/testsuite/gdb.base/corefile.exp
index 04ae969..72c7a4a 100644
--- a/gdb/testsuite/gdb.base/corefile.exp
+++ b/gdb/testsuite/gdb.base/corefile.exp
@@ -142,6 +142,16 @@ gdb_test "print coremaker_ro" "\\\$$decimal = 201"
 
 gdb_test "print func2::coremaker_local" "\\\$$decimal = \\{0, 1, 2, 3, 4\\}"
 
+# Test the presence and the correct values of $_exitsignal and
+# $_exitcode variables.  The corefile is generated with a SIGABRT,
+# which is "6" in the Linux kernel.
+
+gdb_test "print \$_exitsignal" " = 6" \
+    "\$_exitsignal prints SIGABRT (6)"
+
+gdb_test "print \$_exitcode" " = void" \
+    "\$_exitcode is void"
+
 # Somehow we better test the ability to read the registers out of the core
 # file correctly.  I don't think the other tests do this.
 
diff --git a/gdb/testsuite/gdb.base/exitsignal.exp b/gdb/testsuite/gdb.base/exitsignal.exp
new file mode 100644
index 0000000..8687812
--- /dev/null
+++ b/gdb/testsuite/gdb.base/exitsignal.exp
@@ -0,0 +1,106 @@
+# Copyright 2013 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 3 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, see <http://www.gnu.org/licenses/>.
+
+# This test checks both $_exitcode and $_exitsignal variables.  The
+# purpose of this checking is to ensure that the variables are
+# mutually exclusive, i.e., that when $_exitsignal is set, $_exitcode
+# is not, and vice-versa.  This mutual exclusion happens because if an
+# inferior exited (either successfuly or not), it certainly was not
+# killed by a signal.  However, if it was killed by an uncaught
+# signal, then there is no way for it to have exited.
+
+if { [target_info exists gdb,nosignals] } {
+    verbose "Skipping exitsignal.exp because of nosignals."
+    continue
+}
+
+standard_testfile segv.c
+
+if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile}] } {
+    return -1
+}
+
+# Run to main
+if { ![runto_main] } {
+    return -1
+}
+
+# Print $_exitsignal.  It should be void now, because nothing
+# happened.
+gdb_test "print \$_exitsignal" " = void" \
+    "\$_exitsignal is void before running"
+
+# Just to guarantee, making sure that $_exitcode is also void.
+gdb_test "print \$_exitcode" " = void" \
+    "\$_exitcode is void before running"
+
+# Trigger SIGSEGV.
+gdb_test "continue" "Program received signal SIGSEGV.*" "trigger SIGSEGV"
+
+# Continue until the end.
+gdb_test "continue" "Program terminated with signal SIGSEGV.*" \
+    "program terminated with SIGSEGV"
+
+# Now, print $_exitsignal again.  It should be 11 (SIGSEGV).
+gdb_test "print \$_exitsignal" " = 11" \
+    "\$_exitsignal is 11 (SIGSEGV) after SIGSEGV."
+
+# And $_exitcode should still be void, since the inferior died because
+# of a signal, and did not return.
+gdb_test "print \$_exitcode" " = void" \
+    "\$_exitcode is still void after SIGSEGV"
+
+# Re-run to main, i.e., restart the executable.
+rerun_to_main
+
+# Print the $_exitsignal again.  Even in this normal scenario, it
+# should still contain the signal triggered in the other run.
+gdb_test "print \$_exitsignal" " = 11" \
+    "\$_exitsignal is 11 (SIGSEGV) after restarting the inferior"
+
+# And, again, print $_exitcode.
+gdb_test "print \$_exitcode" " = void" \
+    "\$_exitcode is still void after restarting the inferior"
+
+# Now we test the behaviour of $_exit{code,signal} during a normal
+# inferior execution.
+standard_testfile normal.c
+
+if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile}] } {
+    return -1
+}
+
+# Checking $_exitsignal and $_exitcode, both should be void before the
+# inferior is executed.
+gdb_test "print \$_exitsignal" " = void" \
+    "\$_exitsignal is void before normal inferior is executed"
+gdb_test "print \$_exitcode" " = void" \
+    "\$_exitcode is void before normal inferior is executed"
+
+# Run the inferior until the end.
+if { ![runto_main] } {
+    return -1
+}
+
+gdb_continue_to_end
+
+# Checking $_exitcode.  It should be 0.
+gdb_test "print \$_exitcode" " = 0" \
+    "\$_exitcode is zero after normal inferior is executed"
+
+# Checking $_exitsignal.  It should still be void, since the inferior
+# has not received any signal.
+gdb_test "print \$_exitsignal" " = void" \
+    "\$_exitsignal is still void after normal inferior is executed"
diff --git a/gdb/testsuite/gdb.base/normal.c b/gdb/testsuite/gdb.base/normal.c
new file mode 100644
index 0000000..4aa7c45
--- /dev/null
+++ b/gdb/testsuite/gdb.base/normal.c
@@ -0,0 +1,24 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2013 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 3 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, see <http://www.gnu.org/licenses/>.  */
+
+/* This test is just a normal return 0.  */
+
+int
+main (int argc, char *argv[])
+{
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.base/segv.c b/gdb/testsuite/gdb.base/segv.c
new file mode 100644
index 0000000..8991f4d
--- /dev/null
+++ b/gdb/testsuite/gdb.base/segv.c
@@ -0,0 +1,29 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2013 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 3 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, see <http://www.gnu.org/licenses/>.  */
+
+/* This test can be used just to generate a SIGSEGV.  */
+
+#include <signal.h>
+
+int
+main (int argc, char *argv[])
+{
+  /* Generating a SIGSEGV.  */
+  raise (SIGSEGV);
+
+  return 0;
+}

Re: [PATCH v4] Implement $_exitsignal

[Pedro Alves]

On 10/03/2013 09:24 PM, Sergio Durigan Junior wrote:
> gdb/
> 2013-10-02  Sergio Durigan Junior  <sergiodj@redhat.com>
> 
> 	* NEWS: Mention new convenience variable $_exitsignal.
> 	* corelow.c (core_open): Reset exit convenience variables. Set

Double space after period.

> 	$_exitsignal to the uncaught signal which generated the corefile.
> 	* infrun.c (handle_inferior_event): Reset exit convenience
> 	variables.  Set $_exitsignal for TARGET_WAITKIND_SIGNALLED.
> 	(clear_exit_convenience_vars): New function.
> 	* utils.h (clear_exit_convenience_vars): New prototype.

s/utils.h/inferior.h/.

> index 922a0f2..fa8a5d3 100644
> --- a/gdb/inferior.h
> +++ b/gdb/inferior.h
> @@ -639,4 +639,10 @@ extern void signal_catch_update (const unsigned int *);
>  
>  enum gdb_signal gdb_signal_from_command (int num);
>  
> +/* Clear the convenience variables associated with the exit of the
> +   inferior.  Currently, those variables are $_exitcode and
> +   $_exitsignal.  */
> +
> +extern void clear_exit_convenience_vars (void);
> +

Close, but not here.  Look up in the file, you'll find:

>  /* From infrun.c */

Declare the function in that section of the file.

(I'd approve patches that create infrun.h, etc.)

>  #endif /* !defined (INFERIOR_H) */

> @@ -7061,6 +7091,15 @@ save_inferior_ptid (void)
>    *saved_ptid_ptr = inferior_ptid;
>    return make_cleanup (restore_inferior_ptid, saved_ptid_ptr);
>  }
> +
> +/* See comment at utils.h.  */

s/at/in/, I believe.  Or just "See utils.h".

> +/* See comment at utils.h.  */

But most importantly, s/utils.h/inferior.h/.

Okay with these changes.

Thanks,
-- 
Pedro Alves

Re: [PATCH v4] Implement $_exitsignal

[Sergio Durigan Junior]

On Friday, October 04 2013, Pedro Alves wrote:

> On 10/03/2013 09:24 PM, Sergio Durigan Junior wrote:
>> gdb/
>> 2013-10-02  Sergio Durigan Junior  <sergiodj@redhat.com>
>> 
>> 	* NEWS: Mention new convenience variable $_exitsignal.
>> 	* corelow.c (core_open): Reset exit convenience variables. Set
>
> Double space after period.
>
>> 	$_exitsignal to the uncaught signal which generated the corefile.
>> 	* infrun.c (handle_inferior_event): Reset exit convenience
>> 	variables.  Set $_exitsignal for TARGET_WAITKIND_SIGNALLED.
>> 	(clear_exit_convenience_vars): New function.
>> 	* utils.h (clear_exit_convenience_vars): New prototype.
>
> s/utils.h/inferior.h/.
>
>> index 922a0f2..fa8a5d3 100644
>> --- a/gdb/inferior.h
>> +++ b/gdb/inferior.h
>> @@ -639,4 +639,10 @@ extern void signal_catch_update (const unsigned int *);
>>  
>>  enum gdb_signal gdb_signal_from_command (int num);
>>  
>> +/* Clear the convenience variables associated with the exit of the
>> +   inferior.  Currently, those variables are $_exitcode and
>> +   $_exitsignal.  */
>> +
>> +extern void clear_exit_convenience_vars (void);
>> +
>
> Close, but not here.  Look up in the file, you'll find:
>
>>  /* From infrun.c */
>
> Declare the function in that section of the file.
>
> (I'd approve patches that create infrun.h, etc.)
>
>>  #endif /* !defined (INFERIOR_H) */
>
>> @@ -7061,6 +7091,15 @@ save_inferior_ptid (void)
>>    *saved_ptid_ptr = inferior_ptid;
>>    return make_cleanup (restore_inferior_ptid, saved_ptid_ptr);
>>  }
>> +
>> +/* See comment at utils.h.  */
>
> s/at/in/, I believe.  Or just "See utils.h".
>
>> +/* See comment at utils.h.  */
>
> But most importantly, s/utils.h/inferior.h/.
>
> Okay with these changes.

Sorry about those simple mistakes.  Anyway, thanks everybody for the
reviews, the patch is now committed.

         https://sourceware.org/ml/gdb-cvs/2013-10/msg00041.html

-- 
Sergio