Re: [PATCH v2] [PR symtab/17391] gdb internal error: assertion fails in regcache.c:178

[Doug Evans <dje at google dot com>]

On Tue, Aug 18, 2015 at 4:48 AM, Pedro Alves <palves@redhat.com> wrote:
> On 08/18/2015 01:26 AM, Doug Evans wrote:
>
>>   > More like for those I left it wasn't clear to me how to fix them.
>>   > e.g., rs6000-tdep.c:rs6000_dwarf2_reg_to_regnum.
>>   > I'm certainly not making things worse by leaving them alone.
>>   >
>
> OK.  Neither rs6000 spu look like cases that
> returns num_regs + num_pseudo_regs for bad registers, as suggested
> here, though:
>
> +       /* If there's no corresponding GDB register, ignore it.
> +          Some targets return num_regs (+ num_pseudo_regs) for bad registers.
> +          Handle them until they are fixed.  */
>         if (regnum < 0 || regnum >= num_regs)
>           continue;
>
> IMO, as written, this is the sort of comment that ends up staying
> stale forever even after all such targets stop returning num_regs+num_pseudo_regs
> specifically (they may still return bogus register numbers higher
> than that).  After your supplemental patch, I think we can just drop it
> or say "Protect against a target returning a bad register" or some such?
>
>> I missed a few obvious cases.
>> The main remaining cases that I can think of are rs6000 and spu.
>> Plus this supplemental patch makes stabs and ecoff more robust.
>> Stabs was using num_arch + num_pseudo to denote "bad reg",
>> but some targets use the same reg_to_regnum function for both
>> stabs and dwarf, so that's asking for trouble (since dwarf uses -1).
>> This patch makes stabs handle negative regnos too.
>>
>> If it's too hard to review this apart from the original patch
>> I can resubmit the entire thing.
>
> Looks good to me.

Committed with the suggested change. Thanks.