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Re: [RFC 00/13] MIPS64 support
- From: Josh Stone <jistone at redhat dot com>
- To: Mark Wielaard <mark at klomp dot org>, Crestez Dan Leonard <cdleonard at gmail dot com>
- Cc: systemtap at sourceware dot org
- Date: Thu, 14 Aug 2014 13:58:47 -0700
- Subject: Re: [RFC 00/13] MIPS64 support
- Authentication-results: sourceware.org; auth=none
- References: <cover dot 1406837921 dot git dot cdleonard at gmail dot com> <20140801111556 dot GC28053 at toonder dot wildebeest dot org>
FYI for @redhat.com folks, if you got a bounce message from sourceware
today, I believe it's complaining about this message:
https://sourceware.org/ml/systemtap/2014-q3/msg00114.html
Apparently sourceware was happy to accept that .o attachment, but
redhat.com rejects it as "virus Heuristics.Broken.Executable".
On 08/01/2014 04:15 AM, Mark Wielaard wrote:
> Hi,
>
> I didn't review any of the patches yet, but noticed this:
>
> On Thu, Jul 31, 2014 at 11:21:05PM +0300, Crestez Dan Leonard wrote:
>> Inside loc2c the CU address_size is used to determine the max_fetch_size,
>> this becomes incorrect with -msym32. Handling this (patch 8) requires
>> access to the elf header which requires a lot of code churn (patch 7).
>> This could be avoided if elfutils exported a dwarf_die_getdwarf but this
>> would be a new elfutils API.
>
> I believe Josh Stone also wanted a function like that (although I don't
> remember for what, so maybe I am wrong). I think it would be reasonable
> to have such a new function to get at the Dwarf from either a Dwarf_Die
> or Dwarf_CU (which might be helpful if all you have is an Dwarf_Attribute).
>
>> Apparently -msym32 also affects the FDE data for unwind support. It's not
>> clear how to detect it cleanly in there. Apparently an "address_size" field
>> can be included in the CIE, but I don't have it. Both eu-readelf and
>> binutils readelf show corrupt FDEs. Patches 12 and 13 are evil hacks.
>> Presumably I could try to interpret initial_address both ways and attempt
>> to lookup the CU?
>
> Do you have an example ELF/DWARF file that shows this issue?
>
> Thanks,
>
> Mark
>