Re: [PATCH v2] gdb/stack.c: avoid stale pointers when printing frame arguments

[Bruno Larsen <blarsen@redhat.com>]

On 6/20/22 10:12, Bruno Larsen wrote:
> 
> 
> On 6/15/22 12:43, Tom Tromey wrote:
>>>>>>> "Bruno" == Bruno Larsen via Gdb-patches <gdb-patches@sourceware.org> writes:
>>
...
>>
>> Bruno> +  /* print_frame can invalidate frame, so cache the frame_id to rebuild
>> Bruno> +     the whole stack later, if needed.  */
>> Bruno> +  struct frame_id frame_id = get_frame_id (frame);
>>
>> This repeated code makes me wonder if perhaps the print_frame_info API
>> ought to be changed instead.
> 
> print_frame_info could return an updated pointer to the frame being printed, or receive a
> frame_info** and update it in-place.  However, We'll still need to check for a null pointer
> after calling, since we won't want print_frame_info to error out if a frame no longer
> exists.  We might not care when printing.
> 
> Does any of these options sound like a better option? Or would we always want to error out
> if the frame disappears from under us?
> 

I've spent a couple of days checking this, but to avoid repeating the code, there is just so
much to be re-written that trying to fix the issues you had with making frame_info* smart pointers
seems to be a better use of my time.

Is this a blocking issue, or can the patch be merged with some repeated code and we fix this later?


Cheers!
Bruno Larsen
> 
> Cheers!
> Bruno Larsen
>>
>> Tom
>>