From: Richard Sandiford <rdsandiford@googlemail.com>
To: "Moore\, Catherine" <Catherine_Moore@mentor.com>
Cc: "Schmidt\, Bernd" <Bernd_Schmidt@mentor.com>,
"binutils\@sourceware.org" <binutils@sourceware.org>
Subject: Re: [Patch] Gas support for MIPS Compact EH
Date: Tue, 25 Feb 2014 08:29:00 -0000 [thread overview]
Message-ID: <87zjlfegtq.fsf@talisman.default> (raw)
In-Reply-To: <FD3DCEAC5B03E9408544A1E416F11242012EACF998@NA-MBX-01.mgc.mentorg.com> (Catherine Moore's message of "Mon, 24 Feb 2014 20:48:23 +0000")
"Moore, Catherine" <Catherine_Moore@mentor.com> writes:
>> -----Original Message-----
>> From: Richard Sandiford [mailto:rdsandiford@googlemail.com]
>> Sent: Thursday, February 20, 2014 6:37 AM
>> To: Moore, Catherine
>> Cc: Schmidt, Bernd; binutils@sourceware.org
>> Subject: Re: [Patch] Gas support for MIPS Compact EH
>>
>> >
>> > I'd like to take this approach in the next patch:
>> > 1. Keep the R_MIPS_EH relocation
>> > 2. Let the linker choose the appropriate encoding 3. Clean up the
>> > assembler inconsistencies
>>
>> That's OK with me, but just to clarify: (3) IMO means that R_MIPS_EH is
>> never associated with a specific encoding in the assembler. I.e.
>> R_MIPS_EH is purely for an as-yet unknown encoding that is chosen by the
>> linker rather than the assembler or the assembly author. And AIUI the only
>> place that happens is in .eh_frame_entry.
>>
>> Perhaps one way of doing that would to have a generic
>> BFD_RELOC_EH_FRAME_HDR_32 that R_MIPS_EH maps to. Then when
>> emitting the .eh_frame_entry addresses, the assembler unconditionally uses
>> that BFD_RELOC_ rather than a target hook.
>>
>> What do you plan to do for .ehword? Since the assembler generates the
>> .eh_frame_entry itself, and since R_MIPS_EH should only be used there
>> (since that's the only place where the linker controls the encoding), I don't
>> think there are any valid uses of an R_MIPS_EH-producing .ehword.
>>
>
> The current version of the patch generates a BFD_RELOC_32_PCREL when it
> sees the .ehword directive.
> That should be okay going forward, agreed?
Well, PC-relative can be expressed as:
.word foo-.
I think instead we should make that work and drop .ehword, to avoid confusion
with the old behaviour.
Thanks,
Richard
next prev parent reply other threads:[~2014-02-25 8:29 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-31 18:56 Moore, Catherine
2013-06-01 11:07 ` Richard Sandiford
2014-02-04 21:56 ` Moore, Catherine
2014-02-05 22:38 ` Maciej W. Rozycki
2014-02-08 16:34 ` Richard Sandiford
2014-02-08 18:48 ` Bernd Schmidt
2014-02-09 11:11 ` Richard Sandiford
2014-02-19 23:13 ` Moore, Catherine
2014-02-20 11:36 ` Richard Sandiford
2014-02-20 21:24 ` Moore, Catherine
2014-02-20 22:39 ` Richard Sandiford
2014-02-24 20:54 ` Moore, Catherine
2014-02-24 20:48 ` Moore, Catherine
2014-02-25 8:29 ` Richard Sandiford [this message]
2014-03-17 13:22 ` Moore, Catherine
2014-03-17 13:52 ` Richard Sandiford
2014-03-19 21:12 ` Moore, Catherine
2014-03-19 23:45 ` Richard Sandiford
2014-03-20 14:29 ` Moore, Catherine
2014-03-20 21:19 ` Richard Sandiford
2014-03-06 17:44 ` Moore, Catherine
2014-03-06 22:18 ` Richard Sandiford
2014-03-25 13:50 ` Moore, Catherine
2014-03-25 14:06 ` Richard Sandiford
2014-11-17 16:10 ` Moore, Catherine
2014-11-22 14:42 ` Richard Sandiford
2015-02-08 16:59 ` Moore, Catherine
2015-02-08 17:00 ` Moore, Catherine
2015-04-16 13:28 ` Moore, Catherine
2015-05-01 13:54 ` FW: " Moore, Catherine
2015-05-05 10:04 ` Matthew Fortune
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