Re: [PATCH 3/4] Allow display of negative offsets in print_address_symbolic()

[Pedro Alves <palves at redhat dot com>]

On 6/8/19 8:54 PM, Kevin Buettner wrote:
> When examining addresses associated with blocks with non-contiguous
> address ranges, it's not uncommon to see large positive offsets which,
> for some address width, actually represent a smaller negative offset.
> Here's an example taken from the test case:
> 
>     (gdb) x/i foo_cold
>        0x40110d <foo+4294967277>:	push   %rbp
> 
> This commit causes cases like the above to be displayed like this (below)
> instead:
> 
>     (gdb) x/i foo_cold
>        0x40110d <foo-19>:	push   %rbp
> 
> gdb/ChangeLog:
> 
> 	* printcmd.c (print_address_symbolic): Print negative offsets.
> 	(build_address_symbolic): Force signed arithmetic when computing
> 	offset.

Seems reasonable to me, if we assume that the symbol name to put
within <> is "foo".

This change makes makes me doubt that, though.  We're looking at
the lower level, disassembly code.  I think I'd want to see

  0x40110d <foo_cold+0>:

there?

E.g., I might want to follow up with
disassemble foo_cold.

But the present state of things, I wouldn't be able to see the
foo_cold symbol, where it starts?

Maybe a larger disassemble output including several cold sections
in view would help determine the best output.

Thanks,
Pedro Alves