[RFAv4 1/3] default-args: allow to define default command/alias arguments

Christian Biesinger via gdb-patches gdb-patches@sourceware.org
Mon Feb 10 01:21:00 GMT 2020


Hi Philippe,

I have some style comments below.

On Sat, Feb 8, 2020 at 9:10 AM Philippe Waroquiers
<philippe.waroquiers@skynet.be> wrote:
>
> Currently, a user can define an alias, but cannot have default
> arguments for this alias.
>
> This patch provides the following:
>
> * A new command 'set default-args' that can define default args
>   to prepend to the command or alias arguments before executing it.
>   Note that default args can be used for an alias and can nicely
>   combine nested "with" (see below the changes for the alias command).
>
>         (gdb) help set default-args
>         Set or clear default args automatically prepended to a command or alias.
>         Usage: set default-args COMMAND [DEFAULT-ARGS...]
>         Set or clear the default arguments automatically prepended
>         to the arguments the user provides when COMMAND is run.
>         Note that COMMAND can be an alias.  Commands and their aliases
>         do not share their default arguments, so you can specify different
>         default arguments for a command and for each of its aliases.
>         Without the [= DEFAULT-ARGS...], clears COMMAND default arguments.
>
>   Note that 'set default-args' command has a completer to help typing
>   COMMAND and its default-args.
>
> * A new command 'show default-args'.
>
>         (gdb) help show default-args
>         Show the default args of a command, or of all commands.
>         Usage: show default-args [COMMAND]
>         Show the default args of COMMAND.  Without COMMAND, show the default args
>         of all commands.
>
> * The 'alias' command is modified so as to directly accept default-args.
>
>         (gdb) help alias
>         Define a new command that is an alias of an existing command.
>         Usage: alias [-a] [--] ALIAS = COMMAND [DEFAULT-ARGS...]
>         ALIAS is the name of the alias command to create.
>         COMMAND is the command being aliased to.
>
>         Options:
>           -a
>             Specify that ALIAS is an abbreviation of COMMAND.
>             Abbreviations are not shown in command lists displayed by the 'help' command.
>         You can optionally provide DEFAULT-ARGS to define at the same time
>         ALIAS and its default args.  This is the equivalent of:
>           alias ALIAS = COMMAND
>           set default-args ALIAS DEFAULT-ARGS...
>
>         Examples:
>         Make "spe" an alias of "set print elements":
>           alias spe set print elements
>         Make "elms" an alias of "elements" in the "set print" command:
>           alias -a set print elms set print elements
>         Make "btf" an alias of "backtrace -full -past-entry -past-main" :
>           alias btf = backtrace -full -past-entry -past-main
>         Make "wLapPeu" an alias of 2 nested "with":
>           alias wLapPeu = with language pascal -- with print elements unlimited --
>
> * 'alias' command now has a completer that helps to complete:
>      - ALIAS (if the user defines an alias after a prefix),
>      - the aliased COMMAND
>      - the possible options for the aliased COMMAND.
>
> * A new setting 'set enable-default-args'.  This can be used if the
>   user wants to temporarily disable the usage of default args.
>   'show enable-default-args' shows the value of 'enable-default-args'.
>   The main intended usage of this setting is to use it in the "with"
>   command: as set default-args can add arguments to standard GDB commands,
>   it is useful (e.g. in user defined commands) to be able to go back
>   to the 'standard' behaviour of a command.
>
> gdb/ChangeLog
> YYYY-MM-DD  Philippe Waroquiers  <philippe.waroquiers@skynet.be>
>
>         * cli/cli-cmds.c (default_args_cmd_completer)
>         (lookup_cmd_for_default_args, set_default_args_command)
>         (show_default_args, show_default_args_command_1)
>         (show_default_args_command, alias_command_completer)
>         (make_alias_options_def_group): New functions.
>         (alias_opts, alias_option_defs): New struct and array.
>         (alias_usage_error): Update usage.
>         (alias_command): Handles optional DEFAULT-ARGS... arguments.
>         Use option framework.
>         (_initialize_cli_cmds): Install 'set|show default-args' commands.
>         Update alias command help.
>         (show_user, valid_command_p):
>         Add NULL for new default_args lookup_cmd argument.
>         * cli/cli-decode.c (help_cmd): Show default args if command has
>         some.
>         (lookup_cmd_1, lookup_cmd): New argument default_args.
>         (add_alias_cmd):
>         Add NULL for new default_args lookup_cmd argument.
>         (print_help_for_command): Show default args.
>         * cli/cli-decode.h (struct cmd_list_element): New member default_args.
>         xfree default_args in destructor.
>         * cli/cli-script.c (process_next_line, do_define_command):
>         Add NULL for new default_args lookup_cmd argument.
>         * command.h: Declare new default_args argument in lookup_cmd
>         and lookup_cmd_1.
>         * completer.c (complete_line_internal_1):
>         Add NULL for new default_args lookup_cmd or lookup_cmd_1 argument.
>         * guile/scm-cmd.c (gdbscm_parse_command_name): Likewise.
>         * guile/scm-param.c (add_setshow_generic, pascm_parameter_defined_p):
>         Likewise.
>         * infcmd.c (_initialize_infcmd): Likewise.
>         * python/py-auto-load.c (gdbpy_initialize_auto_load): Likewise.
>         * python/py-cmd.c (gdbpy_parse_command_name): Likewise.
>         * python/py-param.c (add_setshow_generic): Likewise.
>         * remote.c (_initialize_remote): Likewise.
>         * top.c (enable_default_args_var): New flag.
>         (execute_command): Prepend default_args if command has some.
>         (set_verbose):
>         Add NULL for new default_args lookup_cmd or  lookup_cmd_1 argument.
>         (init_main): Install 'set|show enable-default-args.
>         * tracepoint.c (validate_actionline, encode_actions_1):
>         Add NULL for new default_args lookup_cmd or lookup_cmd_1 argument.
> ---
>  gdb/cli/cli-cmds.c        | 325 ++++++++++++++++++++++++++++++++++----
>  gdb/cli/cli-decode.c      |  89 +++++++++--
>  gdb/cli/cli-decode.h      |   6 +
>  gdb/cli/cli-script.c      |  12 +-
>  gdb/command.h             |   2 +
>  gdb/completer.c           |   2 +-
>  gdb/guile/scm-cmd.c       |   2 +-
>  gdb/guile/scm-param.c     |   6 +-
>  gdb/infcmd.c              |   6 +-
>  gdb/python/py-auto-load.c |   4 +-
>  gdb/python/py-cmd.c       |   2 +-
>  gdb/python/py-param.c     |   4 +-
>  gdb/remote.c              |   4 +-
>  gdb/top.c                 |  40 ++++-
>  gdb/tracepoint.c          |   6 +-
>  15 files changed, 439 insertions(+), 71 deletions(-)
>
> diff --git a/gdb/cli/cli-cmds.c b/gdb/cli/cli-cmds.c
> index 6f324410e1..d8197aa740 100644
> --- a/gdb/cli/cli-cmds.c
> +++ b/gdb/cli/cli-cmds.c
> @@ -50,6 +50,7 @@
>  #include "cli/cli-cmds.h"
>  #include "cli/cli-style.h"
>  #include "cli/cli-utils.h"
> +#include "cli/cli-style.h"
>
>  #include "extension.h"
>  #include "gdbsupport/pathstuff.h"
> @@ -230,6 +231,7 @@ with_command_1 (const char *set_cmd_prefix,
>      nested_cmd = repeat_previous ();
>
>    cmd_list_element *set_cmd = lookup_cmd (&args, setlist, set_cmd_prefix,
> +                                         nullptr,
>                                           /*allow_unknown=*/ 0,
>                                           /*ignore_help_classes=*/ 1);
>    gdb_assert (set_cmd != nullptr);
> @@ -324,6 +326,146 @@ with_command_completer (struct cmd_list_element *ignore,
>    with_command_completer_1 ("set ", tracker,  text);
>  }
>
> +/* Completer for the "set|show default-args" commands.  */
> +
> +static void
> +default_args_cmd_completer (struct cmd_list_element *ignore,
> +                           completion_tracker &tracker,
> +                           const char *text, const char *word)
> +{
> +  tracker.set_use_custom_word_point (true);
> +
> +  complete_nested_command_line (tracker, text);
> +}
> +
> +/* Look up the contents of TEXT as a command usable with default args.
> +   Throws an error if no such command is found.
> +   Return the found command and advances TEXT past the found command.
> +   If the found command is a postfix command, set *PREFIX_CMD to its prefix command.  */
> +
> +static struct cmd_list_element *
> +lookup_cmd_for_default_args (const char **text,
> +                            struct cmd_list_element **prefix_cmd)
> +{
> +  const char *orig_text = *text;
> +  struct cmd_list_element *lcmd, *alias, *cmd;

I think in new functions it would be better to move declarations to
where they are first used.

> +
> +  if (*text == nullptr || skip_spaces (*text) == nullptr)
> +    error (_("COMMAND missing."));
> +
> +  /* We first use lookup_cmd to verify TEXT unambiguously identifies
> +     a command.  */
> +  lcmd = lookup_cmd (text, cmdlist, "", NULL,
> +                    /*allow_unknown=*/ 0,
> +                    /*ignore_help_classes=*/ 1);
> +
> +  /* Note that we accept default args for prefix commands,
> +     as a prefix command can also be a valid usable
> +     command accepting some arguments.
> +     For example, "thread apply" applies a command to a
> +     list of thread ids, and is also the prefix command for
> +     thread apply all.  */
> +
> +  /* We have an unambiguous command for which default args
> +     can be specified.  What remains after having fond LCMD
> +     is either spaces, or the default args character.  */
> +
> +  /* We then use lookup_cmd_composition to detect if the user
> +     has specified an alias, and find the possible prefix_cmd
> +     of cmd.  */
> +  lookup_cmd_composition
> +    (std::string (orig_text, *text - orig_text).c_str (),
> +     &alias, prefix_cmd, &cmd);
> +  gdb_assert (cmd != nullptr);
> +  gdb_assert (cmd == lcmd);
> +  if (alias != nullptr)
> +    cmd = alias;
> +
> +  return cmd;
> +}
> +
> +/* Implementation of the "set default-args" command.  */
> +
> +static void
> +set_default_args_command (const char *arg, int from_tty)
> +{
> +  struct cmd_list_element *prefix_cmd;
> +  struct cmd_list_element *cmd = lookup_cmd_for_default_args (&arg, &prefix_cmd);
> +
> +  const char *default_args = skip_spaces (arg);
> +
> +  if (*default_args == '\0')
> +    default_args = nullptr;
> +
> +  if (cmd->default_args)
> +    xfree ((char *) cmd->default_args);
> +  if (default_args == nullptr)
> +    cmd->default_args = nullptr;
> +  else
> +    cmd->default_args = xstrdup (default_args);
> +}
> +
> +/* Print a message showing C's name and its default args or <no default args>
> +   if C has no default args.
> +   If SILENT_FOR_NO_DEFAULT_ARGS, does nothing if C has no default args.  */
> +
> +static void
> +show_default_args (struct cmd_list_element *c,
> +                  const char *prefix,
> +                  bool silent_for_no_default_args)
> +{
> +  if (c->default_args != nullptr || !silent_for_no_default_args)
> +    {
> +      fputs_filtered ("default-args ", gdb_stdout);
> +      fprintf_styled (gdb_stdout, title_style.style (),
> +                     "%s%s",
> +                     prefix == nullptr ? "" : prefix, c->name);
> +      fprintf_filtered (gdb_stdout, " = %s\n",
> +                       c->default_args == nullptr
> +                       ? "<no default args>" : c->default_args);
> +    }
> +}
> +
> +/* Recursively traverse COMMANDLIST and prints a message showing
> +   the default-args of the commands that have non-null default args.
> +   PREFIX is the prefix that led to COMMANDLIST.  */
> +
> +static void
> +show_default_args_command_1 (struct cmd_list_element *commandlist,
> +                            const char *prefix)
> +{
> +  /* Walk through the commands.  */
> +  for (cmd_list_element *c = commandlist; c; c = c->next)
> +    {
> +      show_default_args (c, prefix, true);
> +      /* If C has subcommands, recursively search if its subcommands
> +        have default args.
> +        Do not recurse for abbreviations to avoid duplicates
> +        in the output.  */
> +      if (c->prefixlist != NULL && !c->abbrev_flag)
> +       show_default_args_command_1 (*c->prefixlist, c->prefixname);
> +    }
> +}
> +
> +/* Implementation of the "show default-args" command.  */
> +
> +static void
> +show_default_args_command (const char *arg, int from_tty)
> +{
> +  if (skip_spaces (arg) != nullptr)
> +    {
> +      struct cmd_list_element *prefix_cmd;
> +      struct cmd_list_element *c = lookup_cmd_for_default_args (&arg,
> +                                                               &prefix_cmd);
> +
> +      show_default_args (c,
> +                        prefix_cmd == nullptr ? "" : prefix_cmd->prefixname,
> +                        false);
> +    }
> +  else
> +    show_default_args_command_1 (cmdlist, "");
> +}
> +
>
>  /* Provide documentation on command or list given by COMMAND.  FROM_TTY
>     is ignored.  */
> @@ -1550,7 +1692,7 @@ show_user (const char *args, int from_tty)
>      {
>        const char *comname = args;
>
> -      c = lookup_cmd (&comname, cmdlist, "", 0, 1);
> +      c = lookup_cmd (&comname, cmdlist, "", NULL, 0, 1);
>        if (!cli_user_command_p (c))
>         error (_("Not a user command."));
>        show_user_1 (c, "", args, gdb_stdout);
> @@ -1582,6 +1724,71 @@ apropos_command (const char *arg, int from_tty)
>    apropos_cmd (gdb_stdout, cmdlist, verbose, pattern, "");
>  }
>
> +/* The options for the "alias" command.  */
> +
> +struct alias_opts
> +{
> +  /* For "-a".  */
> +  bool abbrev_flag = 0;
> +};
> +
> +static const gdb::option::option_def alias_option_defs[] = {
> +
> +  gdb::option::flag_option_def<alias_opts> {
> +    "a",
> +    [] (alias_opts *opts) { return &opts->abbrev_flag; },
> +    N_("Specify that ALIAS is an abbreviation of COMMAND.\n\
> +Abbreviations are not shown in command lists displayed by the 'help' command."),
> +  },
> +
> +};
> +
> +/* Create an option_def_group for the "alias" options, with
> +   A_OPTS as context.  */
> +
> +static inline gdb::option::option_def_group
> +make_alias_options_def_group (alias_opts *a_opts)
> +{
> +  return {{alias_option_defs}, a_opts};
> +}
> +
> +/* Completer for the "alias_command".  */
> +
> +static void
> +alias_command_completer (struct cmd_list_element *ignore,
> +                        completion_tracker &tracker,
> +                        const char *text, const char *word)
> +{
> +  const auto grp = make_alias_options_def_group (nullptr);
> +
> +  tracker.set_use_custom_word_point (true);
> +
> +  if (gdb::option::complete_options
> +      (tracker, &text, gdb::option::PROCESS_OPTIONS_UNKNOWN_IS_ERROR, grp))
> +    return;
> +
> +  const char *delim = strstr (text, "=");

strchr?

> +
> +  /* If we're past the "=" delimiter, complete the
> +     "alias ALIAS = COMMAND [DEFAULT-ARGS...]" as if the user is
> +     typing COMMAND DEFAULT-ARGS...  */
> +  if (delim != text
> +      && delim != nullptr
> +      && isspace (delim[-1])
> +      && (isspace (delim[1]) || delim[1] == '\0'))
> +    {
> +      std::string new_text = std::string (delim + 1);
> +
> +      tracker.advance_custom_word_point_by (delim + 1 - text);
> +      complete_nested_command_line (tracker, new_text.c_str ());
> +      return;
> +    }
> +
> +  /* We're not yet past the "=" delimiter.  Complete a command, as
> +     the user might type an alias following a prefix command.  */
> +  complete_nested_command_line (tracker, text);
> +}
> +
>  /* Subroutine of alias_command to simplify it.
>     Return the first N elements of ARGV flattened back to a string
>     with a space separating each element.
> @@ -1616,7 +1823,7 @@ valid_command_p (const char *command)
>  {
>    struct cmd_list_element *c;
>
> -  c = lookup_cmd_1 (& command, cmdlist, NULL, 1);
> +  c = lookup_cmd_1 (& command, cmdlist, NULL, NULL, 1);
>
>    if (c == NULL || c == (struct cmd_list_element *) -1)
>      return false;
> @@ -1634,7 +1841,7 @@ valid_command_p (const char *command)
>  static void
>  alias_usage_error (void)
>  {
> -  error (_("Usage: alias [-a] [--] ALIAS = COMMAND"));
> +  error (_("Usage: alias [-a] [--] ALIAS = COMMAND [DEFAULT-ARGS...]"));
>  }
>
>  /* Make an alias of an existing command.  */
> @@ -1642,8 +1849,13 @@ alias_usage_error (void)
>  static void
>  alias_command (const char *args, int from_tty)
>  {
> +  alias_opts a_opts;
> +
> +  auto grp = make_alias_options_def_group (&a_opts);
> +  gdb::option::process_options
> +    (&args, gdb::option::PROCESS_OPTIONS_UNKNOWN_IS_ERROR, grp);
> +
>    int i, alias_argc, command_argc;
> -  int abbrev_flag = 0;
>    const char *equals;
>    const char *alias, *command;
>
> @@ -1654,24 +1866,18 @@ alias_command (const char *args, int from_tty)
>    std::string args2 (args, equals - args);
>
>    gdb_argv built_alias_argv (args2.c_str ());
> -  gdb_argv command_argv (equals + 1);
> +
> +  const char *default_args = equals + 1;
> +  struct cmd_list_element *c_command_prefix;
> +
> +  lookup_cmd_for_default_args (&default_args, &c_command_prefix);
> +  std::string command_argv_str (equals + 1,
> +                               default_args == nullptr
> +                               ? strlen (equals + 1)
> +                               : default_args - equals - 1);
> +  gdb_argv command_argv (command_argv_str.c_str ());
>
>    char **alias_argv = built_alias_argv.get ();
> -  while (alias_argv[0] != NULL)
> -    {
> -      if (strcmp (alias_argv[0], "-a") == 0)
> -       {
> -         ++alias_argv;
> -         abbrev_flag = 1;
> -       }
> -      else if (strcmp (alias_argv[0], "--") == 0)
> -       {
> -         ++alias_argv;
> -         break;
> -       }
> -      else
> -       break;
> -    }
>
>    if (alias_argv[0] == NULL || command_argv[0] == NULL
>        || *alias_argv[0] == '\0' || *command_argv[0] == '\0')
> @@ -1706,6 +1912,8 @@ alias_command (const char *args, int from_tty)
>    if (valid_command_p (alias))
>      error (_("Alias already exists: %s"), alias);
>
> +  struct cmd_list_element *alias_cmd;
> +
>    /* If ALIAS is one word, it is an alias for the entire COMMAND.
>       Example: alias spe = set print elements
>
> @@ -1718,8 +1926,8 @@ alias_command (const char *args, int from_tty)
>    if (alias_argc == 1)
>      {
>        /* add_cmd requires *we* allocate space for name, hence the xstrdup.  */
> -      add_com_alias (xstrdup (alias_argv[0]), command, class_alias,
> -                    abbrev_flag);
> +      alias_cmd = add_com_alias (xstrdup (alias_argv[0]), command, class_alias,
> +                                a_opts.abbrev_flag);
>      }
>    else
>      {
> @@ -1739,19 +1947,30 @@ alias_command (const char *args, int from_tty)
>        alias_prefix = alias_prefix_string.c_str ();
>        command_prefix = command_prefix_string.c_str ();
>
> -      c_command = lookup_cmd_1 (& command_prefix, cmdlist, NULL, 1);
> +      c_command = lookup_cmd_1 (& command_prefix, cmdlist, NULL, NULL, 1);
>        /* We've already tried to look up COMMAND.  */
>        gdb_assert (c_command != NULL
>                   && c_command != (struct cmd_list_element *) -1);
>        gdb_assert (c_command->prefixlist != NULL);
> -      c_alias = lookup_cmd_1 (& alias_prefix, cmdlist, NULL, 1);
> +      c_alias = lookup_cmd_1 (& alias_prefix, cmdlist, NULL, NULL, 1);
>        if (c_alias != c_command)
>         error (_("ALIAS and COMMAND prefixes do not match."));
>
>        /* add_cmd requires *we* allocate space for name, hence the xstrdup.  */
> -      add_alias_cmd (xstrdup (alias_argv[alias_argc - 1]),
> -                    command_argv[command_argc - 1],
> -                    class_alias, abbrev_flag, c_command->prefixlist);
> +      alias_cmd = add_alias_cmd (xstrdup (alias_argv[alias_argc - 1]),
> +                                command_argv[command_argc - 1],
> +                                class_alias, a_opts.abbrev_flag,
> +                                c_command->prefixlist);
> +    }
> +
> +  gdb_assert (alias_cmd);
> +  gdb_assert (alias_cmd->default_args == nullptr);
> +  if (default_args != nullptr)
> +    {
> +      default_args = skip_spaces (default_args);
> +
> +      if (*default_args != '\0')
> +       alias_cmd->default_args = xstrdup (default_args);
>      }
>  }
>
> @@ -1940,7 +2159,7 @@ setting_cmd (const char *fnname, struct cmd_list_element *showlist,
>      error (_("First argument of %s must be a string."), fnname);
>
>    const char *a0 = (const char *) value_contents (argv[0]);
> -  cmd_list_element *cmd = lookup_cmd (&a0, showlist, "", -1, 0);
> +  cmd_list_element *cmd = lookup_cmd (&a0, showlist, "", NULL, -1, 0);
>
>    if (cmd == nullptr || cmd_type (cmd) != show_cmd)
>      error (_("First argument of %s must be a "
> @@ -2299,6 +2518,26 @@ You can supply a command number to start with, or a `+' to start after\n\
>  the previous command number shown."),
>            &showlist);
>
> +  c = add_cmd ("default-args", class_support, set_default_args_command, _("\
> +Set or clear default args automatically prepended to a command or alias.\n\
> +Usage: set default-args COMMAND [DEFAULT-ARGS...]\n\
> +Set or clear the default arguments automatically prepended\n\
> +to the arguments the user provides when COMMAND is run.\n\
> +Note that COMMAND can be an alias.  Commands and their aliases\n\
> +do not share their default arguments, so you can specify different\n\
> +default arguments for a command and for each of its aliases.\n\
> +Without the [= DEFAULT-ARGS...], clears COMMAND default arguments."),
> +          &setlist);
> +  set_cmd_completer_handle_brkchars (c, default_args_cmd_completer);
> +
> +  c = add_cmd ("default-args", class_support, show_default_args_command, _("\
> +Show the default args of a command, or of all commands.\n\
> +Usage: show default-args [COMMAND]\n\
> +Show the default args of COMMAND.  Without COMMAND, show the default args\n\
> +of all commands."),
> +          &showlist);
> +  set_cmd_completer_handle_brkchars (c, default_args_cmd_completer);
> +
>    add_cmd ("version", no_set_class, show_version,
>            _("Show what version of GDB this is."), &showlist);
>
> @@ -2450,19 +2689,37 @@ When 'on', each command is displayed as it is executed."),
>                            NULL,
>                            &setlist, &showlist);
>
> -  c = add_com ("alias", class_support, alias_command, _("\
> +  const auto alias_opts = make_alias_options_def_group (nullptr);
> +
> +  static std::string alias_help
> +    = gdb::option::build_help (_("\
>  Define a new command that is an alias of an existing command.\n\
> -Usage: alias [-a] [--] ALIAS = COMMAND\n\
> +Usage: alias [-a] [--] ALIAS = COMMAND [DEFAULT-ARGS...]\n\
>  ALIAS is the name of the alias command to create.\n\
>  COMMAND is the command being aliased to.\n\
> -If \"-a\" is specified, the command is an abbreviation,\n\
> -and will not appear in help command list output.\n\
> +\n\
> +Options:\n\
> +%OPTIONS%\n\
> +You can optionally provide DEFAULT-ARGS to define at the same time\n\
> +ALIAS and its default args.  This is the equivalent of:\n\
> +  alias ALIAS = COMMAND\n\
> +  set default-args ALIAS DEFAULT-ARGS...\n\
>  \n\
>  Examples:\n\
>  Make \"spe\" an alias of \"set print elements\":\n\
> -  alias spe = set print elements\n\
> +  alias spe set print elements\n\
>  Make \"elms\" an alias of \"elements\" in the \"set print\" command:\n\
> -  alias -a set print elms = set print elements"));
> +  alias -a set print elms set print elements\n\
> +Make \"btf\" an alias of \"backtrace -full -past-entry -past-main\" :\n\
> +  alias btf = backtrace -full -past-entry -past-main\n\
> +Make \"wLapPeu\" an alias of 2 nested \"with\":\n\
> +  alias wLapPeu = with language pascal -- with print elements unlimited --"),
> +                              alias_opts);
> +
> +  c = add_com ("alias", class_support, alias_command,
> +              alias_help.c_str ());
> +
> +  set_cmd_completer_handle_brkchars (c, alias_command_completer);
>
>    const char *source_help_text = xstrprintf (_("\
>  Read commands from a file named FILE.\n\
> diff --git a/gdb/cli/cli-decode.c b/gdb/cli/cli-decode.c
> index 7aecd9897e..8cfff843d2 100644
> --- a/gdb/cli/cli-decode.c
> +++ b/gdb/cli/cli-decode.c
> @@ -343,7 +343,7 @@ add_alias_cmd (const char *name, const char *oldname,
>    struct cmd_list_element *old;
>
>    tmp = oldname;
> -  old = lookup_cmd (&tmp, *list, "", 1, 1);
> +  old = lookup_cmd (&tmp, *list, "", NULL, 1, 1);
>
>    return add_alias_cmd (name, old, theclass, abbrev_flag, list);
>  }
> @@ -1045,6 +1045,7 @@ void
>  help_cmd (const char *command, struct ui_file *stream)
>  {
>    struct cmd_list_element *c;
> +  const char *initial_command = command;
>
>    if (!command)
>      {
> @@ -1058,7 +1059,7 @@ help_cmd (const char *command, struct ui_file *stream)
>        return;
>      }
>
> -  c = lookup_cmd (&command, cmdlist, "", 0, 0);
> +  c = lookup_cmd (&command, cmdlist, "", NULL, 0, 0);
>
>    if (c == 0)
>      return;
> @@ -1078,6 +1079,41 @@ help_cmd (const char *command, struct ui_file *stream)
>    fputs_filtered (c->doc, stream);
>    fputs_filtered ("\n", stream);
>
> +  if (c->func != nullptr)
> +    {
> +      /* Print the default args of the command if it has some.
> +        Use lookup_cmd_composition to find if help was requested for
> +        an alias.  In this case, rather print the alias default_args.  */
> +
> +      struct cmd_list_element *alias, *prefix_cmd, *cmd;
> +      const char *name, *default_args;
> +
> +      lookup_cmd_composition (initial_command,
> +                             &alias, &prefix_cmd, &cmd);
> +      gdb_assert (cmd != nullptr);
> +      gdb_assert (cmd == c);
> +
> +      if (alias == nullptr)
> +       {
> +         name = c->name;
> +         default_args = c->default_args;
> +       }
> +      else
> +       {
> +         name = alias->name;
> +         default_args = alias->default_args;
> +       }
> +      if (default_args != nullptr)
> +       {
> +         fputs_filtered ("default-args ", stream);
> +         fprintf_styled (stream, title_style.style (),
> +                         "%s%s",
> +                         prefix_cmd == nullptr ? "" : prefix_cmd->prefixname,
> +                         name);
> +         fprintf_filtered (stream, " = %s\n", default_args);
> +       }
> +    }
> +
>    if (c->prefixlist == 0 && c->func != NULL)
>      return;
>    fprintf_filtered (stream, "\n");
> @@ -1271,6 +1307,13 @@ print_help_for_command (struct cmd_list_element *c, const char *prefix,
>    fputs_filtered (" -- ", stream);
>    print_doc_line (stream, c->doc, false);
>    fputs_filtered ("\n", stream);
> +  if (c->default_args != nullptr)
> +    {
> +      fputs_filtered ("  default-args ", stream);
> +      fprintf_styled (stream, title_style.style (),
> +                     "%s%s", prefix, c->name);
> +      fprintf_filtered (stream, " = %s\n", c->default_args);
> +    }
>
>    if (recurse
>        && c->prefixlist != 0
> @@ -1422,8 +1465,12 @@ valid_user_defined_cmd_name_p (const char *name)
>     the list in which there are ambiguous choices (and *TEXT will be set to
>     the ambiguous text string).
>
> +   if DEFAULT_ARGS is not null and the found command has default args defined,
> +   then *DEFAULT_ARGS points at these default args.
> +
>     If the located command was an abbreviation, this routine returns the base
> -   command of the abbreviation.
> +   command of the abbreviation.  Note that *DEFAULT_ARGS will point at the
> +   default args defined for the alias.
>
>     It does no error reporting whatsoever; control will always return
>     to the superior routine.
> @@ -1450,11 +1497,13 @@ valid_user_defined_cmd_name_p (const char *name)
>
>  struct cmd_list_element *
>  lookup_cmd_1 (const char **text, struct cmd_list_element *clist,
> -             struct cmd_list_element **result_list, int ignore_help_classes)
> +             struct cmd_list_element **result_list, const char **default_args,
> +             int ignore_help_classes)
>  {
>    char *command;
>    int len, nfound;
>    struct cmd_list_element *found, *c;
> +  bool found_alias = false;
>    const char *line = *text;
>
>    while (**text == ' ' || **text == '\t')
> @@ -1490,6 +1539,8 @@ lookup_cmd_1 (const char **text, struct cmd_list_element *clist,
>         /* Will be modified in calling routine
>            if we know what the prefix command is.  */
>         *result_list = 0;
> +      if (default_args != NULL)
> +       *default_args = nullptr;

NULL -> nullptr, for consistency between these two lines?

>        return CMD_LIST_AMBIGUOUS;       /* Ambiguous.  */
>      }
>
> @@ -1505,22 +1556,30 @@ lookup_cmd_1 (const char **text, struct cmd_list_element *clist,
>         are warning about the alias, we may also warn about the command
>         itself and we will adjust the appropriate DEPRECATED_WARN_USER
>         flags.  */
> -
> +
>        if (found->deprecated_warn_user)
>         deprecated_cmd_warning (line);
> +
> +      /* Return the default_args of the alias, not the default_args
> +        of the command it is pointing to.  */
> +      if (default_args != NULL)
> +       *default_args = found->default_args;
>        found = found->cmd_pointer;
> +      found_alias = true;
>      }
>    /* If we found a prefix command, keep looking.  */
>
>    if (found->prefixlist)
>      {
>        c = lookup_cmd_1 (text, *found->prefixlist, result_list,
> -                       ignore_help_classes);
> +                       default_args, ignore_help_classes);
>        if (!c)
>         {
>           /* Didn't find anything; this is as far as we got.  */
>           if (result_list != NULL)
>             *result_list = clist;
> +         if (!found_alias && default_args != NULL)
> +           *default_args = found->default_args;
>           return found;
>         }
>        else if (c == CMD_LIST_AMBIGUOUS)
> @@ -1535,6 +1594,9 @@ lookup_cmd_1 (const char **text, struct cmd_list_element *clist,
>                  at the top of this function to clarify what is
>                  supposed to be going on.  */
>               *result_list = found;
> +         /* For ambiguous commands, do not return any default_args args.  */
> +         if (default_args != nullptr)
> +           *default_args = nullptr;
>           return c;
>         }
>        else
> @@ -1547,6 +1609,8 @@ lookup_cmd_1 (const char **text, struct cmd_list_element *clist,
>      {
>        if (result_list != NULL)
>         *result_list = clist;
> +      if (!found_alias && default_args != NULL)
> +       *default_args = found->default_args;
>        return found;
>      }
>  }
> @@ -1566,8 +1630,14 @@ undef_cmd_error (const char *cmdtype, const char *q)
>
>  /* Look up the contents of *LINE as a command in the command list LIST.
>     LIST is a chain of struct cmd_list_element's.
> -   If it is found, return the struct cmd_list_element for that command
> -   and update *LINE to point after the command name, at the first argument.
> +   If it is found, return the struct cmd_list_element for that command,
> +   update *LINE to point after the command name, at the first argument
> +   and update *DEFAULT_ARGS (if DEFAULT_ARGS is not null) to point at
> +   the default args to prepend to the user provided args when running
> +   the command.
> +   Note that if the found cmd_list_element is found via an alias,
> +   the default args of the alias are returned.
> +
>     If not found, call error if ALLOW_UNKNOWN is zero
>     otherwise (or if error returns) return zero.
>     Call error if specified command is ambiguous,
> @@ -1581,6 +1651,7 @@ undef_cmd_error (const char *cmdtype, const char *q)
>  struct cmd_list_element *
>  lookup_cmd (const char **line, struct cmd_list_element *list,
>             const char *cmdtype,
> +           const char **default_args,
>             int allow_unknown, int ignore_help_classes)
>  {
>    struct cmd_list_element *last_list = 0;
> @@ -1592,7 +1663,7 @@ lookup_cmd (const char **line, struct cmd_list_element *list,
>    if (!*line)
>      error (_("Lack of needed %scommand"), cmdtype);
>
> -  c = lookup_cmd_1 (line, list, &last_list, ignore_help_classes);
> +  c = lookup_cmd_1 (line, list, &last_list, default_args, ignore_help_classes);
>
>    if (!c)
>      {
> diff --git a/gdb/cli/cli-decode.h b/gdb/cli/cli-decode.h
> index 4f7c7701e4..92bff3b38c 100644
> --- a/gdb/cli/cli-decode.h
> +++ b/gdb/cli/cli-decode.h
> @@ -72,6 +72,8 @@ struct cmd_list_element
>         xfree ((char *) doc);
>        if (name_allocated)
>         xfree ((char *) name);
> +      if (default_args)
> +       xfree ((char *) default_args);
>      }
>
>      DISABLE_COPY_AND_ASSIGN (cmd_list_element);
> @@ -183,6 +185,10 @@ struct cmd_list_element
>      /* Hook for another command to be executed after this command.  */
>      struct cmd_list_element *hook_post = nullptr;
>
> +    /* Default arguments to automatically prepend to the user
> +       provided arguments when running this command or alias.  */
> +    const char *default_args = nullptr;

Have you considered making this an std::string or unique_xmalloc_ptr
to simplify the memory management/?

> +
>      /* Nonzero identifies a prefix command.  For them, the address
>         of the variable containing the list of subcommands.  */
>      struct cmd_list_element **prefixlist = nullptr;
> diff --git a/gdb/cli/cli-script.c b/gdb/cli/cli-script.c
> index c9d2378906..e912613785 100644
> --- a/gdb/cli/cli-script.c
> +++ b/gdb/cli/cli-script.c
> @@ -974,7 +974,7 @@ process_next_line (const char *p, struct command_line **command,
>        /* Resolve command abbreviations (e.g. 'ws' for 'while-stepping').  */
>        const char *cmd_name = p;
>        struct cmd_list_element *cmd
> -       = lookup_cmd_1 (&cmd_name, cmdlist, NULL, 1);
> +       = lookup_cmd_1 (&cmd_name, cmdlist, NULL, NULL, 1);
>        cmd_name = skip_spaces (cmd_name);
>        bool inline_cmd = *cmd_name != '\0';
>
> @@ -1331,7 +1331,7 @@ validate_comname (const char **comname)
>        std::string prefix (*comname, last_word - 1);
>        const char *tem = prefix.c_str ();
>
> -      c = lookup_cmd (&tem, cmdlist, "", 0, 1);
> +      c = lookup_cmd (&tem, cmdlist, "", NULL, 0, 1);
>        if (c->prefixlist == NULL)
>         error (_("\"%s\" is not a prefix command."), prefix.c_str ());
>
> @@ -1387,7 +1387,7 @@ do_define_command (const char *comname, int from_tty,
>
>    /* Look it up, and verify that we got an exact match.  */
>    tem = comname;
> -  c = lookup_cmd (&tem, *list, "", -1, 1);
> +  c = lookup_cmd (&tem, *list, "", NULL, -1, 1);
>    if (c && strcmp (comname, c->name) != 0)
>      c = 0;
>
> @@ -1432,7 +1432,7 @@ do_define_command (const char *comname, int from_tty,
>      {
>        /* Look up cmd it hooks, and verify that we got an exact match.  */
>        tem = comname + hook_name_size;
> -      hookc = lookup_cmd (&tem, *list, "", -1, 0);
> +      hookc = lookup_cmd (&tem, *list, "", NULL, -1, 0);
>        if (hookc && strcmp (comname + hook_name_size, hookc->name) != 0)
>         hookc = 0;
>        if (!hookc && commands == nullptr)
> @@ -1518,7 +1518,7 @@ document_command (const char *comname, int from_tty)
>    list = validate_comname (&comname);
>
>    tem = comname;
> -  c = lookup_cmd (&tem, *list, "", 0, 1);
> +  c = lookup_cmd (&tem, *list, "", NULL, 0, 1);
>
>    if (c->theclass != class_user)
>      error (_("Command \"%s\" is built-in."), comfull);
> @@ -1567,7 +1567,7 @@ define_prefix_command (const char *comname, int from_tty)
>
>    /* Look it up, and verify that we got an exact match.  */
>    tem = comname;
> -  c = lookup_cmd (&tem, *list, "", -1, 1);
> +  c = lookup_cmd (&tem, *list, "", NULL, -1, 1);
>    if (c != nullptr && strcmp (comname, c->name) != 0)
>      c = nullptr;
>
> diff --git a/gdb/command.h b/gdb/command.h
> index 7f436c72c9..cb28dd94cb 100644
> --- a/gdb/command.h
> +++ b/gdb/command.h
> @@ -252,11 +252,13 @@ extern enum cmd_types cmd_type (struct cmd_list_element *cmd);
>  extern struct cmd_list_element *lookup_cmd (const char **,
>                                             struct cmd_list_element *,
>                                             const char *,
> +                                           const char **,
>                                             int, int);
>
>  extern struct cmd_list_element *lookup_cmd_1 (const char **,
>                                               struct cmd_list_element *,
>                                               struct cmd_list_element **,
> +                                             const char **,
>                                               int);
>
>  extern struct cmd_list_element *deprecate_cmd (struct cmd_list_element *,
> diff --git a/gdb/completer.c b/gdb/completer.c
> index 619fb8a028..5e9b13aa90 100644
> --- a/gdb/completer.c
> +++ b/gdb/completer.c
> @@ -1324,7 +1324,7 @@ complete_line_internal_1 (completion_tracker &tracker,
>      }
>    else
>      {
> -      c = lookup_cmd_1 (&p, cmdlist, &result_list, ignore_help_classes);
> +      c = lookup_cmd_1 (&p, cmdlist, &result_list, NULL, ignore_help_classes);
>      }
>
>    /* Move p up to the next interesting thing.  */
> diff --git a/gdb/guile/scm-cmd.c b/gdb/guile/scm-cmd.c
> index ec1adffa25..8fd2772df4 100644
> --- a/gdb/guile/scm-cmd.c
> +++ b/gdb/guile/scm-cmd.c
> @@ -512,7 +512,7 @@ gdbscm_parse_command_name (const char *name,
>    prefix_text[i + 1] = '\0';
>
>    prefix_text2 = prefix_text;
> -  elt = lookup_cmd_1 (&prefix_text2, *start_list, NULL, 1);
> +  elt = lookup_cmd_1 (&prefix_text2, *start_list, NULL, NULL, 1);
>    if (elt == NULL || elt == CMD_LIST_AMBIGUOUS)
>      {
>        msg = xstrprintf (_("could not find command prefix '%s'"), prefix_text);
> diff --git a/gdb/guile/scm-param.c b/gdb/guile/scm-param.c
> index b72766523a..62e2108740 100644
> --- a/gdb/guile/scm-param.c
> +++ b/gdb/guile/scm-param.c
> @@ -466,13 +466,13 @@ add_setshow_generic (enum var_types param_type, enum command_class cmd_class,
>    /* Lookup created parameter, and register Scheme object against the
>       parameter context.  Perform this task against both lists.  */
>    tmp_name = cmd_name;
> -  param = lookup_cmd (&tmp_name, *show_list, "", 0, 1);
> +  param = lookup_cmd (&tmp_name, *show_list, "", NULL, 0, 1);
>    gdb_assert (param != NULL);
>    set_cmd_context (param, self);
>    *set_cmd = param;
>
>    tmp_name = cmd_name;
> -  param = lookup_cmd (&tmp_name, *set_list, "", 0, 1);
> +  param = lookup_cmd (&tmp_name, *set_list, "", NULL, 0, 1);
>    gdb_assert (param != NULL);
>    set_cmd_context (param, self);
>    *show_cmd = param;
> @@ -969,7 +969,7 @@ pascm_parameter_defined_p (const char *name, struct cmd_list_element *list)
>  {
>    struct cmd_list_element *c;
>
> -  c = lookup_cmd_1 (&name, list, NULL, 1);
> +  c = lookup_cmd_1 (&name, list, NULL, NULL, 1);
>
>    /* If the name is ambiguous that's ok, it's a new parameter still.  */
>    return c != NULL && c != CMD_LIST_AMBIGUOUS;
> diff --git a/gdb/infcmd.c b/gdb/infcmd.c
> index 62890bde2a..fd754ea7f9 100644
> --- a/gdb/infcmd.c
> +++ b/gdb/infcmd.c
> @@ -3191,7 +3191,7 @@ is restored."),
>                                      show_inferior_tty_command,
>                                      &setlist, &showlist);
>    cmd_name = "inferior-tty";
> -  c = lookup_cmd (&cmd_name, setlist, "", -1, 1);
> +  c = lookup_cmd (&cmd_name, setlist, "", NULL, -1, 1);
>    gdb_assert (c != NULL);
>    add_alias_cmd ("tty", c, class_alias, 0, &cmdlist);
>
> @@ -3204,7 +3204,7 @@ Follow this command with any number of args, to be passed to the program."),
>                                    set_args_command,
>                                    show_args_command,
>                                    &setlist, &showlist);
> -  c = lookup_cmd (&cmd_name, setlist, "", -1, 1);
> +  c = lookup_cmd (&cmd_name, setlist, "", NULL, -1, 1);
>    gdb_assert (c != NULL);
>    set_cmd_completer (c, filename_completer);
>
> @@ -3223,7 +3223,7 @@ working directory."),
>                                    set_cwd_command,
>                                    show_cwd_command,
>                                    &setlist, &showlist);
> -  c = lookup_cmd (&cmd_name, setlist, "", -1, 1);
> +  c = lookup_cmd (&cmd_name, setlist, "", NULL, -1, 1);
>    gdb_assert (c != NULL);
>    set_cmd_completer (c, filename_completer);
>
> diff --git a/gdb/python/py-auto-load.c b/gdb/python/py-auto-load.c
> index 2084fc43ff..56db946463 100644
> --- a/gdb/python/py-auto-load.c
> +++ b/gdb/python/py-auto-load.c
> @@ -84,12 +84,12 @@ Show the debugger's behaviour regarding auto-loaded Python scripts, "
>                            NULL, NULL, show_auto_load_python_scripts,
>                            &setlist, &showlist);
>    cmd_name = "auto-load-scripts";
> -  cmd = lookup_cmd (&cmd_name, setlist, "", -1, 1);
> +  cmd = lookup_cmd (&cmd_name, setlist, "", NULL, -1, 1);
>    deprecate_cmd (cmd, "set auto-load python-scripts");
>
>    /* It is needed because lookup_cmd updates the CMD_NAME pointer.  */
>    cmd_name = "auto-load-scripts";
> -  cmd = lookup_cmd (&cmd_name, showlist, "", -1, 1);
> +  cmd = lookup_cmd (&cmd_name, showlist, "", NULL, -1, 1);
>    deprecate_cmd (cmd, "show auto-load python-scripts");
>
>    add_cmd ("python-scripts", class_info, info_auto_load_python_scripts,
> diff --git a/gdb/python/py-cmd.c b/gdb/python/py-cmd.c
> index b822c14004..b8e2c365ee 100644
> --- a/gdb/python/py-cmd.c
> +++ b/gdb/python/py-cmd.c
> @@ -390,7 +390,7 @@ gdbpy_parse_command_name (const char *name,
>    std::string prefix_text (name, i + 1);
>
>    prefix_text2 = prefix_text.c_str ();
> -  elt = lookup_cmd_1 (&prefix_text2, *start_list, NULL, 1);
> +  elt = lookup_cmd_1 (&prefix_text2, *start_list, NULL, NULL, 1);
>    if (elt == NULL || elt == CMD_LIST_AMBIGUOUS)
>      {
>        PyErr_Format (PyExc_RuntimeError, _("Could not find command prefix %s."),
> diff --git a/gdb/python/py-param.c b/gdb/python/py-param.c
> index 7b183cfa55..fb39187b18 100644
> --- a/gdb/python/py-param.c
> +++ b/gdb/python/py-param.c
> @@ -569,12 +569,12 @@ add_setshow_generic (int parmclass, enum command_class cmdclass,
>    /* Lookup created parameter, and register Python object against the
>       parameter context.  Perform this task against both lists.  */
>    tmp_name = cmd_name;
> -  param = lookup_cmd (&tmp_name, *show_list, "", 0, 1);
> +  param = lookup_cmd (&tmp_name, *show_list, "", NULL, 0, 1);
>    if (param)
>      set_cmd_context (param, self);
>
>    tmp_name = cmd_name;
> -  param = lookup_cmd (&tmp_name, *set_list, "", 0, 1);
> +  param = lookup_cmd (&tmp_name, *set_list, "", NULL, 0, 1);
>    if (param)
>      set_cmd_context (param, self);
>  }
> diff --git a/gdb/remote.c b/gdb/remote.c
> index 34a8a08f56..3396a80b87 100644
> --- a/gdb/remote.c
> +++ b/gdb/remote.c
> @@ -14373,10 +14373,10 @@ If set, a break, instead of a cntrl-c, is sent to the remote target."),
>                            set_remotebreak, show_remotebreak,
>                            &setlist, &showlist);
>    cmd_name = "remotebreak";
> -  cmd = lookup_cmd (&cmd_name, setlist, "", -1, 1);
> +  cmd = lookup_cmd (&cmd_name, setlist, "", NULL, -1, 1);
>    deprecate_cmd (cmd, "set remote interrupt-sequence");
>    cmd_name = "remotebreak"; /* needed because lookup_cmd updates the pointer */
> -  cmd = lookup_cmd (&cmd_name, showlist, "", -1, 1);
> +  cmd = lookup_cmd (&cmd_name, showlist, "", NULL, -1, 1);
>    deprecate_cmd (cmd, "show remote interrupt-sequence");
>
>    add_setshow_enum_cmd ("interrupt-sequence", class_support,
> diff --git a/gdb/top.c b/gdb/top.c
> index f702af9acd..2042f3d473 100644
> --- a/gdb/top.c
> +++ b/gdb/top.c
> @@ -549,6 +549,11 @@ set_repeat_arguments (const char *args)
>    repeat_arguments = args;
>  }
>
> +/* Flag for whether we want to use the configured default args.
> +   Default is yes.  */
> +
> +static bool enable_default_args_var = true;
> +
>  /* Execute the line P as a command, in the current user context.
>     Pass FROM_TTY as second argument to the defining function.  */
>
> @@ -577,6 +582,8 @@ execute_command (const char *p, int from_tty)
>      {
>        const char *cmd = p;
>        const char *arg;
> +      const char *default_args;
> +      std::string default_args_and_arg;
>        int was_sync = current_ui->prompt_state == PROMPT_BLOCKED;
>
>        line = p;
> @@ -584,15 +591,27 @@ execute_command (const char *p, int from_tty)
>        /* If trace-commands is set then this will print this command.  */
>        print_command_trace ("%s", p);
>
> -      c = lookup_cmd (&cmd, cmdlist, "", 0, 1);
> +      c = lookup_cmd (&cmd, cmdlist, "", &default_args, 0, 1);
>        p = cmd;
>
>        scoped_restore save_repeat_args
>         = make_scoped_restore (&repeat_arguments, nullptr);
>        const char *args_pointer = p;
>
> -      /* Pass null arg rather than an empty one.  */
> -      arg = *p ? p : 0;
> +      if (default_args != nullptr && enable_default_args_var)
> +       {
> +         if (*p)
> +           default_args_and_arg = std::string (default_args)
> +             + ' ' + std::string (p);
> +         else
> +           default_args_and_arg = std::string (default_args);
> +         arg = default_args_and_arg.c_str ();
> +       }
> +      else
> +       {
> +         /* Pass null arg rather than an empty one.  */
> +         arg = *p ? p : 0;
> +       }
>
>        /* FIXME: cagney/2002-02-02: The c->type test is pretty dodgy
>           while the is_complete_command(cfunc) test is just plain
> @@ -1935,7 +1954,7 @@ set_verbose (const char *args, int from_tty, struct cmd_list_element *c)
>    const char *cmdname = "verbose";
>    struct cmd_list_element *showcmd;
>
> -  showcmd = lookup_cmd_1 (&cmdname, showlist, NULL, 1);
> +  showcmd = lookup_cmd_1 (&cmdname, showlist, NULL, NULL, 1);
>    gdb_assert (showcmd != NULL && showcmd != CMD_LIST_AMBIGUOUS);
>
>    if (c->doc && c->doc_allocated)
> @@ -2171,6 +2190,19 @@ EMACS-like or VI-like commands like control-P or ESC."),
>                            show_editing,
>                            &setlist, &showlist);
>
> +  add_setshow_boolean_cmd ("enable-default-args", class_support,
> +                          &enable_default_args_var, _("\
> +Set whether GDB prepends default args when running a command.\n\
> +The default args for a command are configured using\n\
> +\"set default-args COMMAND = DEFAULT-ARGS..."), _("\
> +Show whether GDB prepends default args when running a command."), _("\
> +Use \"on\" to enable the usage of the configured default args,\n\
> +and \"off\" to disable it.\n\
> +Without an argument, default args usage is enabled."),
> +                          NULL,
> +                          NULL,
> +                          &setlist, &showlist);
> +
>    add_setshow_boolean_cmd ("save", no_class, &write_history_p, _("\
>  Set saving of the history record on exit."), _("\
>  Show saving of the history record on exit."), _("\
> diff --git a/gdb/tracepoint.c b/gdb/tracepoint.c
> index aa6bea4a8f..26df3e0f61 100644
> --- a/gdb/tracepoint.c
> +++ b/gdb/tracepoint.c
> @@ -651,7 +651,7 @@ validate_actionline (const char *line, struct breakpoint *b)
>    if (*p == '#')               /* comment line */
>      return;
>
> -  c = lookup_cmd (&p, cmdlist, "", -1, 1);
> +  c = lookup_cmd (&p, cmdlist, "", NULL, -1, 1);
>    if (c == 0)
>      error (_("`%s' is not a tracepoint action, or is ambiguous."), p);
>
> @@ -1303,7 +1303,7 @@ encode_actions_1 (struct command_line *action,
>        action_exp = action->line;
>        action_exp = skip_spaces (action_exp);
>
> -      cmd = lookup_cmd (&action_exp, cmdlist, "", -1, 1);
> +      cmd = lookup_cmd (&action_exp, cmdlist, "", NULL, -1, 1);
>        if (cmd == 0)
>         error (_("Bad action list item: %s"), action_exp);
>
> @@ -2673,7 +2673,7 @@ trace_dump_actions (struct command_line *action,
>        if (*action_exp == '#')  /* comment line */
>         continue;
>
> -      cmd = lookup_cmd (&action_exp, cmdlist, "", -1, 1);
> +      cmd = lookup_cmd (&action_exp, cmdlist, "", NULL, -1, 1);
>        if (cmd == 0)
>         error (_("Bad action list item: %s"), action_exp);
>
> --
> 2.20.1
>



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