Re: [PATCH 0/4] Non-contiguous address range bug fixes / improvements

[Kevin Buettner <kevinb at redhat dot com>]

On Wed, 26 Jun 2019 11:24:46 -0600
Tom Tromey <tom@tromey.com> wrote:

> >>>>> "Kevin" == Kevin Buettner <kevinb@redhat.com> writes:  
> 
> Kevin> This four part series fixes some bugs associated with GDB's non-contiguous
> Kevin> address range support.  
> 
> This is not really related to your patches, but since you have been
> working in this area, I thought I'd ask.
> 
> I ran into a case where gdb will mis-report a breakpoint location in a
> certain situation (that is, "info b" will show something odd for the
> source location).  After debugging for a while, my theory is that the
> problem occurs because the executable has non-contiguous address ranges.
> 
> In particular, find_pc_sect_line is written to first find the symtab
> with the smallest overall range that encloses the PC, and then to find a
> matching symbol in the symtab.  But, with non-contiguous ranges, this
> can yield a sub-optimal result -- because the overall range of a symtab
> not longer really says anything about whether it holds the best symbol.
> 
> Have you seen anything like this?  (I guess not since I'd imagine you'd
> have written a patch ;-)
> 
> I was thinking perhaps the best fix would be to search the blockvectors
> for a definitively enclosing block.  I wonder what you think.

Hi Tom,

I hadn't encountered this (yet), but I have no doubt that there are still
some things to be fixed.

I'll play around with my test case to see if I can reproduce the behavior
that you've described.

Kevin