Re: Status 2009-02-02

[Petr Machata <pmachata at redhat dot com>]

Roland McGrath wrote:
>>       * Check that each rangelistptr is aligned to CU's address_size
> 
> This is canonical but not actually mandatory.

It's a message with impact 4.  If it's not a big deal, I'll make it 2 
(i.e. harmless, but suspicious).

>>         - DW_OP_bra and DW_OP_skip: that they don't overrun or underrun 
>> opcode buffer, and that their destination address is aligned with the 
>> beginning of some DIE.
> 
> Of some op in that expression block, you mean?

Yes, that.

> I've also added the location list C++ interface.  You can use that to apply
> similar checks for addresses used in location lists.  For now, the only
> check I'd recommend is that a location list's addresses all fall into the
> ranges of a scope containing the one whose loclistptr attr is that list.

Ok.

> Parts of text not covered by any CU are not suspicious even if they are not
> just alignment padding and so on--there are sometimes files linked in that
> were compiled without -g, or assembly, which is commonly done with without
> -g, or static libraries, crt1.o, etc.

I see, I didn't think about that.

> The address validity checks that make sense to do by default are just that
> they match some section.  In relocatable cases, it makes sense to check
> that both the start and end of one pair point to the same section.  In
> final-linked cases, that might still make sense but maybe not.  It probably
> also makes sense to check that addresses are inside the st_value+st_size of
> some symbol in the section.  Worrying about it being the right symbol is
> much hair for much later.

Ok.

Thanks,
PM

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