Re: [RFA 2/3] Allow - in %p for printf

[Alan Hayward <Alan dot Hayward at arm dot com>]

> On 15 Feb 2018, at 20:50, Tom Tromey <tom@tromey.com> wrote:
> 
> PR cli/19918 points out that a printf format like "%-5p" will cause a
> gdb crash.  The bug is problem is that printf_pointer doesn't take the
> "-" flag into account.
> 
> gdb/ChangeLog
> 2018-02-14  Tom Tromey  <tom@tromey.com>
> 
> 	PR cli/19918:
> 	* printcmd.c (printf_pointer): Allow "-" in format.
> 
> gdb/testsuite/ChangeLog
> 2018-02-14  Tom Tromey  <tom@tromey.com>
> 
> 	PR cli/19918:
> 	* gdb.base/printcmds.exp (test_printf): Add printf test using '-'
> 	flag.
> ---
> gdb/ChangeLog                        | 5 +++++
> gdb/printcmd.c                       | 5 +++--
> gdb/testsuite/ChangeLog              | 6 ++++++
> gdb/testsuite/gdb.base/printcmds.exp | 4 ++++
> 4 files changed, 18 insertions(+), 2 deletions(-)
> 
> diff --git a/gdb/printcmd.c b/gdb/printcmd.c
> index 13b967f0a2..d2d13895f6 100644
> --- a/gdb/printcmd.c
> +++ b/gdb/printcmd.c
> @@ -2399,8 +2399,9 @@ printf_pointer (struct ui_file *stream, const char *format,
>   if (val != 0)
>     *fmt_p++ = '#';
> 
> -  /* Copy any width.  */
> -  while (*p >= '0' && *p < '9')
> +  /* Copy any width or flags.  Only the "-" flag is needed -- see the
> +     format_pieces constructor.  */

I found this comment a little confusing. How about something like:
Copy and width or flags. “-“ is the only valid flag for pointers — see the format_pieces constructor.

Otherwise looks good to me.

> +  while (*p == '-' || (*p >= '0' && *p < '9'))
>     *fmt_p++ = *p++;
> 
>   gdb_assert (*p == 'p' && *(p + 1) == '\0');
> diff --git a/gdb/testsuite/gdb.base/printcmds.exp b/gdb/testsuite/gdb.base/printcmds.exp
> index 9402d97ef3..56cedb908f 100644
> --- a/gdb/testsuite/gdb.base/printcmds.exp
> +++ b/gdb/testsuite/gdb.base/printcmds.exp
> @@ -776,6 +776,10 @@ proc test_printf {} {
> 	"" \
> 	"create hibob command"
>     gdb_test "hibob" "hi bob zzz.*y" "run hibob command"
> +
> +    # PR cli/19918.
> +    gdb_test "printf \"%-16dq\\n\", 0" "0               q"
> +    gdb_test "printf \"%-16pq\\n\", 0" "\\(nil\\)           q"
> }
> 
> #Test printing DFP values with printf
> -- 
> 2.13.6
>