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From: Florian Weimer <fweimer@redhat.com>
To: Indu Bhagat <indu.bhagat@oracle.com>
Cc: binutils@sourceware.org
Subject: Re: Missing alignment in SFrame spec
References: <87ildgbf9g.fsf@oldenburg.str.redhat.com>
	<2485551a-9608-e4ff-8d4c-bd7974c6c695@oracle.com>
Date: Tue, 02 May 2023 08:03:25 +0200
In-Reply-To: <2485551a-9608-e4ff-8d4c-bd7974c6c695@oracle.com> (Indu Bhagat's
	message of "Mon, 1 May 2023 17:24:49 -0700")
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* Indu Bhagat:

> On 4/28/23 01:08, Florian Weimer wrote:
>> The SFrame specification does not say anything explict about alignment.
>> It uses ATTRIBUTE_PACKED, which strongly suggests alignment 1, but
>> looking at the structures themselves, I think what you actually want is
>> 4-byte alignment.
>> Thanks,
>> Florian
>> 
>
> Hi Florian,
>
> SFrame stack trace format is an unaligned on-disk format. IIUC, you
> suggest 4 byte alignment for all structs in SFrame format?
>
> Yes, current SFrame FDE and SFrame FRE are 1-byte aligned.
>
> I had reasoned about unaligned accesses previously when a bug showed up.

Well, GAS seems to generate 8-byte-aligned .sframe sections (at least in
the 2.40-7.fc39 Fedora package).  So all this is a bit inconsistent.

Thanks,
Florian