Re: [RFA] Show locno for 'multi location' breakpoint hit msg+conv var $bkptno $locno.

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sun, 17 Apr 2022 17:53:11 +0200
> From: Philippe Waroquiers via Gdb-patches <gdb-patches@sourceware.org>
> 
> Before this patch, when a breakpoint that has multiple locations is reached,
> GDB printed:
>   Thread 1 "zeoes" hit Breakpoint 1, some_func () at somefunc1.c:5
> 
> This patch changes the message so that bkpt_print_id prints the precise
> encountered breakpoint:
>   Thread 1 "zeoes" hit Breakpoint 1.2, some_func () at somefunc1.c:5
> 
> In mi mode, bkpt_print_id also (optionally) prints a new table field "locno":
>   locno is printed when the breakpoint has more than one location.
> Note that according to the GDB user manual node 'GDB/MI Development and Front
> Ends', it is ok to add new fields without changing the MI version.

Thanks.  I think this should be an optional feature.  Not everyone is
interested in the particular location that breaks.  Having to disable
the breakpoints by locations is definitely an annoyance.

> diff --git a/gdb/NEWS b/gdb/NEWS
> index 760cb2b7abc..673607dfbb3 100644
> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -14,6 +14,20 @@
>    emit to indicate where a breakpoint should be placed to break in a function
>    past its prologue.
>  
> +* When a breakpoint with multiple locations is hit, GDB now also prints the location
> +  using the syntax <breakpoint_number>.<location_number> such as in:
> +     Thread 1 "zeoes" hit Breakpoint 2.3, some_func () at zeoes.c:8
> +
> +* When a breakpoint is hit, GDB now sets the convenience variables $bkpno and
> +  $locno to the hit breakpoint number and location number.
> +  This allows to disable the last hit breakpoint using for example
> +     (gdb) disable $bkptno
> +   or
> +     (gdb) disable $bkptno.$locno
> +  These commands can be used inside the command list of a breakpoint to
> +  automatically disable the just encountered breakpoint (or breakpoint
> +  specific location).
> +
>  * New commands
> [...]
> +* MI changes
> +
> + ** The 'breakpoint-hit' stopped reason async record now contains an optional field
> +    locno giving the location number when the breakpoint has multiple locations.
> +

This part is OK.

> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index c1e9b09e833..8408928648e 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -4338,9 +4338,15 @@ are operated on.
>  @cindex latest breakpoint
>  Breakpoints are set with the @code{break} command (abbreviated
>  @code{b}).  The debugger convenience variable @samp{$bpnum} records the
> -number of the breakpoint you've set most recently; see @ref{Convenience
> -Vars,, Convenience Variables}, for a discussion of what you can do with
> -convenience variables.
> +number of the breakpoint you've set most recently.
> +A breakpoint may be mapped to multiple locations for example with
> +inlined functions, Ada generics, c++ templates or overloaded function names.
                                    ^^^
I believe we use "C@t{++}" markup for C++ language in the manual.

> +When your program stops on a breakpoint, the convenience variables
> +@samp{$bpkpno} and @samp{$locno} are respectively set to the number of
> +the encountered breakpoint and the number of the breakpoint location.

Please add here index entries for these two variables.

> +For a @samp{breakpoint-hit} stopped reason, when the breakpoint
> +encountered has multiple locations, the field @samp{bkptno} is
> +followed by the field @samp{locno}.

How about an example here?

Thanks.