gdb: add remove-symbol-file command completion

The 'remove-symbol-file' command doesn't currently offer command
completion.  This commit addresses this.

The 'remove-symbol-file' uses gdb_argv to split its command arguments,
this means that the filename the command expects can be quoted.

However, the 'remove-symbol-file' command is a little weird in that it
also has a '-a' option, if this option is passed then the command
expects not a filename, but an address.

Currently the remove_symbol_file_command function splits the command
args using gdb_argv, checks for a '-a' flag by looking at the first
argument value, and then expects the filename or address to occupy a
single entry in the gdb_argv array.

The first thing I do is handle the '-a' flag using GDB's option
system.  I model this option as a flag_option_def (a boolean option).

I've dropped the use of gdb_argv and instead use the new(ish) function
extract_single_filename_arg, which was added a couple of commits back,
to parse the filename argument (when '-a' is not given).

If '-a' is given the the remove-symbol-file command expects an address
rather than a filename.  As we previously split the arguments using
gdb_argv this meant the address needed to appear as a single
argument.  So a user could write:

  (gdb) remove-symbol-file 0x1234

Or they could write:

  (gdb) remove-symbol-file some_function

Both of these would work fine.  But a user could not write:

  (gdb) remove-symbol-file some_function + 0x1000

As only the 'some_function' part would be processed.  Now the user
could do this:

  (gdb) remove-symbol-file "some_function + 0x1000"

By enclosing the address expression in quotes this would be handled as
a single argument.  However, this is a little weird, that's not how
commands like 'print' or 'x' work.  Also this functionality was
neither documented, or tested.

And so, in this commit, by removing the use of gdb_argv I bring the
'remove-symbol-file' command inline with GDB's other commands that
take an expression, the quotes are no longer needed.

Usually in a completer we call 'complete_options', but don't actually
capture the option values.  But for remove-symbol-file I do.  This
allows me to spot when the '-a' option has been given, I can then
complete the rest of the command line as either a filename or an
expression.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>
5 files changed