Re: [RFA] (Ada) Add gdb-mi support for stopping at start of exception handler.

[Simon Marchi <simon dot marchi at ericsson dot com>]

On 2018-01-03 06:09 AM, Xavier Roirand wrote:
> Following my previous commit which add support for stopping at start of
> exception handler, this commit adds required gdb-mi support for this
> feature.

Hi Xavier,

This patch would need to update the documentation, and probably add a NEWS
entry (I always forget those too).

I would like to try running the test, but I am not able to catch handlers with
my setup, I get the "Your Ada runtime appears to be missing some debugging information"
message.  I am on Ubuntu 16.04, do you know how to set up the environment on that
distro to get it working, is it just a matter of installing the right package?  Right
now I have the gnat-5 package installed, from the xenial-updates official repository.

I have a few comments below, nothing big.

> gdb/ChangeLog:
> 
>         * mi-cmd-catch.c (mi_cmd_catch_handlers): New function.
>         * mi-cmds.c (struct mi_cmds): Add catch-handlers command.
>         * mi-cmds.h (mi_cmd_catch_handlers): Add external declaration.
> 
> gdb/testsuite/ChangeLog:
>         * gdb.ada/mi_catch_ex_hand.exp: New testcase.

There's a new .adb file too, you should mention it.

> 
> Tested on x86_64-linux.
> ---
>  gdb/mi/mi-cmd-catch.c                          |  73 +++++++++++++
>  gdb/mi/mi-cmds.c                               |   2 +
>  gdb/mi/mi-cmds.h                               |   1 +
>  gdb/testsuite/gdb.ada/mi_catch_ex_hand.exp     | 141 +++++++++++++++++++++++++
>  gdb/testsuite/gdb.ada/mi_catch_ex_hand/foo.adb |  33 ++++++
>  5 files changed, 250 insertions(+)
>  create mode 100644 gdb/testsuite/gdb.ada/mi_catch_ex_hand.exp
>  create mode 100644 gdb/testsuite/gdb.ada/mi_catch_ex_hand/foo.adb
> 
> diff --git a/gdb/mi/mi-cmd-catch.c b/gdb/mi/mi-cmd-catch.c
> index 9c103d2..964b1a8 100644
> --- a/gdb/mi/mi-cmd-catch.c
> +++ b/gdb/mi/mi-cmd-catch.c
> @@ -167,6 +167,79 @@ mi_cmd_catch_exception (const char *cmd, char *argv[], int argc)
>  				   temp, enabled, 0);
>  }
>  
> +/* Handler for the -catch-handlers command.  */
> +
> +void
> +mi_cmd_catch_handlers (const char *cmd, char *argv[], int argc)
> +{
> +  struct gdbarch *gdbarch = get_current_arch();

Space before ().

> +  char *condition = NULL;
> +  int enabled = 1;
> +  char *exception_name = NULL;
> +  int temp = 0;
> +  enum ada_exception_catchpoint_kind ex_kind = ada_catch_handlers;
> +
> +  int oind = 0;
> +  char *oarg;
> +
> +  enum opt
> +    {
> +      OPT_CONDITION, OPT_DISABLED, OPT_EXCEPTION_NAME, OPT_TEMP,
> +      OPT_UNHANDLED,

I think unhandled is unused in the context of this function.

> +    };
> +  static const struct mi_opt opts[] =
> +    {
> +      { "c", OPT_CONDITION, 1},
> +      { "d", OPT_DISABLED, 0 },
> +      { "e", OPT_EXCEPTION_NAME, 1 },
> +      { "t", OPT_TEMP, 0 },
> +      { "u", OPT_UNHANDLED, 0},> +      { 0, 0, 0 }
> +    };
> +
> +  for (;;)
> +    {
> +      int opt = mi_getopt ("-catch-handlers", argc, argv, opts,
> +			   &oind, &oarg);
> +
> +      if (opt < 0)
> +        break;
> +
> +      switch ((enum opt) opt)
> +        {
> +	case OPT_CONDITION:
> +	  condition = oarg;
> +	  break;
> +	case OPT_DISABLED:
> +	  enabled = 0;
> +	  break;
> +	case OPT_EXCEPTION_NAME:
> +	  exception_name = oarg;
> +	  break;
> +	case OPT_TEMP:
> +	  temp = 1;
> +	  break;
> +        }
> +    }
> +
> +  /* This command does not accept any argument.  Make sure the user
> +     did not provide any.  */
> +  if (oind != argc)
> +    error (_("Invalid argument: %s"), argv[oind]);
> +
> +  scoped_restore restore_breakpoint_reporting
> +    = setup_breakpoint_reporting ();
> +  /* create_ada_exception_catchpoint needs EXCEPTION_NAME and CONDITION
> +     to be xstrdup'ed, and will assume control of their lifetime.  */
> +  if (exception_name != NULL)
> +    exception_name = xstrdup (exception_name);
> +  if (condition != NULL)
> +    condition = xstrdup (condition);
> +  create_ada_exception_catchpoint (gdbarch, ex_kind,
> +				   exception_name, condition,
> +				   temp, enabled, 0);
> +}
> +
>  /* Common path for the -catch-load and -catch-unload.  */
>  
>  static void
> diff --git a/gdb/mi/mi-cmds.c b/gdb/mi/mi-cmds.c
> index 18f6653..310be51 100644
> --- a/gdb/mi/mi-cmds.c
> +++ b/gdb/mi/mi-cmds.c
> @@ -69,6 +69,8 @@ static struct mi_cmd mi_cmds[] =
>                     &mi_suppress_notification.breakpoint),
>    DEF_MI_CMD_MI_1 ("catch-exception", mi_cmd_catch_exception,
>                     &mi_suppress_notification.breakpoint),
> +  DEF_MI_CMD_MI_1 ("catch-handlers", mi_cmd_catch_handlers,
> +                   &mi_suppress_notification.breakpoint),
>    DEF_MI_CMD_MI_1 ("catch-load", mi_cmd_catch_load,
>                     &mi_suppress_notification.breakpoint),
>    DEF_MI_CMD_MI_1 ("catch-unload", mi_cmd_catch_unload,
> diff --git a/gdb/mi/mi-cmds.h b/gdb/mi/mi-cmds.h
> index 03a11c0..52785e9 100644
> --- a/gdb/mi/mi-cmds.h
> +++ b/gdb/mi/mi-cmds.h
> @@ -41,6 +41,7 @@ extern mi_cmd_argv_ftype mi_cmd_break_passcount;
>  extern mi_cmd_argv_ftype mi_cmd_break_watch;
>  extern mi_cmd_argv_ftype mi_cmd_catch_assert;
>  extern mi_cmd_argv_ftype mi_cmd_catch_exception;
> +extern mi_cmd_argv_ftype mi_cmd_catch_handlers;
>  extern mi_cmd_argv_ftype mi_cmd_catch_load;
>  extern mi_cmd_argv_ftype mi_cmd_catch_unload;
>  extern mi_cmd_argv_ftype mi_cmd_disassemble;
> diff --git a/gdb/testsuite/gdb.ada/mi_catch_ex_hand.exp b/gdb/testsuite/gdb.ada/mi_catch_ex_hand.exp
> new file mode 100644
> index 0000000..544e0d8
> --- /dev/null
> +++ b/gdb/testsuite/gdb.ada/mi_catch_ex_hand.exp
> @@ -0,0 +1,141 @@
> +# Copyright 2011-2018 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/>.
> +
> +load_lib "ada.exp"
> +
> +standard_ada_testfile foo
> +
> +if {[gdb_compile_ada "${srcfile}" "${binfile}" executable [list debug additional_flags=-gnata ]] != "" } {
> +  return -1
> +}
> +
> +# Some global variables used to simplify the maintenance of some of
> +# the regular expressions below.
> +set any_nb "\[0-9\]+"

There is $decimal that is defined to the same thing as any_nb by Dejagnu.  I would suggest
using that instead (especially since you already use it in this test).

> +set eol "\[\r\n\]+"
> +
> +# Before going any further, verify that we can insert exception
> +# handlers catchpoints...  That way, we won't have to do this while
> +# doing the actual GDB/MI testing.
> +
> +clean_restart ${testfile}
> +
> +if ![runto_main] then {
> +   fail "cannot run to main, testcase aborted"
> +   return 0
> +}
> +
> +set msg "insert catchpoint on all Ada exceptions handlers"
> +gdb_test_multiple "catch handlers" $msg {
> +    -re "Catchpoint $any_nb: all Ada exceptions handlers$eol$gdb_prompt $" {
> +	pass $msg
> +    }
> +    -re "Your Ada runtime appears to be missing some debugging information.*\[\r\n\]+$gdb_prompt $" {
> +	# If the runtime was not built with enough debug information,
> +	# or if it was stripped, we can not test exception
> +	# catchpoints.
> +	unsupported $msg
> +	return -1
> +    }
> +}
> +
> +# Now, we can start the GDB/MI testing itself...
> +
> +load_lib mi-support.exp
> +set MIFLAGS "-i=mi"
> +
> +gdb_exit
> +if [mi_gdb_start] {
> +    continue
> +}
> +
> +mi_delete_breakpoints
> +mi_gdb_reinitialize_dir $srcdir/$subdir
> +mi_gdb_load ${binfile}

These last three actions are done in mi_run_to_main, so you can remove them.

> +
> +#############################################
> +# 1. Try catching all exceptions handlers.  #
> +#############################################
> +
> +if ![mi_run_to_main] then {
> +   fail "cannot run to main, testcase aborted"
> +   return 0
> +}
> +
> +mi_gdb_test "-catch-handlers" \
> +            "\\^done,bkptno=\"$decimal\",bkpt={.*disp=\"keep\",enabled=\"y\",addr=\"$hex\",what=\"all Ada exceptions handlers\",.*}" \
> +            "catch all exceptions handlers"
> +
> +# Continue to exception handler.
> +
> +proc continue_to_exception_handler { test line } {
> +    global hex any_nb
> +
> +    mi_send_resuming_command "exec-continue" "$test"
> +
> +    # Now MI stream output.
> +    mi_expect_stop \
> +	"breakpoint-hit\",disp=\"keep\",bkptno=\"$any_nb\",exception-name=\"exception\"?" \
> +	"foo" "" ".*" "$line" \
> +	".*" \
> +        $test
> +}
> +
> +# We don't have the exception name info when stopping at the exception handlers
> +# breakpoint so we use source line to check if the inferior stops at the
> +# right location.
> +
> +set bp_ce_location [gdb_get_line_number "BREAK1" ${testdir}/foo.adb]
> +continue_to_exception_handler \
> +    "continue until CE handling caught by all-exceptions handlers catchpoint" \
> +    "$bp_ce_location"
> +
> +set bp_pe_location [gdb_get_line_number "BREAK2" ${testdir}/foo.adb]
> +continue_to_exception_handler \
> +    "continue until PE handling caught by all-exceptions handlers catchpoint" \
> +    "$bp_pe_location"
> +
> +##########################################################
> +# 2. Try catching only some of the exceptions handlers.  #
> +##########################################################
> +
> +# Here is the scenario:
> +#  - Restart the debugger from scratch, runto_main
> +#  - We'll catch only "Constraint_Error handlers"
> +#  - continue, we should stop at the Constraint_Error exception handler
> +#  - continue, we should not stop at the Program_Error exception handler
> +#    but exits instead.

exits -> exit

> +
> +if ![mi_run_to_main] then {
> +   fail "cannot run to main, testcase aborted"
> +   return 0
> +}
> +
> +mi_gdb_test "-catch-handlers -e Constraint_Error" \
> +            "\\^done,bkptno=\"$decimal\",bkpt={.*disp=\"keep\",enabled=\"y\",addr=\"$hex\",what=\"`Constraint_Error' Ada exception handlers\",.*}" \
> +            "catch Constraint_Error"
> +
> +mi_execute_to "exec-continue" \
> +              "breakpoint-hit\",disp=\"keep\",bkptno=\"$any_nb\",exception-name=\"exception\"?" \
> +              "foo" "" ".*" "$bp_ce_location" \
> +              ".*" \
> +              "continue to exception catchpoint hit"
> +
> +# Exit the inferior.
> +mi_send_resuming_command "exec-continue" "continuing to inferior exit"
> +mi_expect_stop "exited-normally" "" "" "" "" "" "exit normally"
> +
> +mi_gdb_exit
> +return 0
> diff --git a/gdb/testsuite/gdb.ada/mi_catch_ex_hand/foo.adb b/gdb/testsuite/gdb.ada/mi_catch_ex_hand/foo.adb
> new file mode 100644
> index 0000000..da701a3
> --- /dev/null
> +++ b/gdb/testsuite/gdb.ada/mi_catch_ex_hand/foo.adb
> @@ -0,0 +1,33 @@
> +--  Copyright 2007-2018 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/>.
> +
> +procedure Foo is
> +begin
> +
> +   begin
> +      raise Constraint_Error;
> +   exception
> +      when Constraint_Error => -- BREAK1
> +         null;
> +   end;
> +
> +   begin
> +      raise Program_Error;
> +   exception
> +      when Program_Error => -- BREAK2
> +         null;
> +   end;
> +
> +end Foo;
> 

Thanks,

Simon