From: Fangrui Song <i@maskray.me>
To: Andrew Pinski <pinskia@gmail.com>
Cc: binutils <binutils@sourceware.org>
Subject: Re: [MIPS] Can we have R_MIPS_PC64?
Date: Sat, 08 Feb 2020 18:40:00 -0000 [thread overview]
Message-ID: <20200208183958.v4vfdtfstlwtod3p@google.com> (raw)
In-Reply-To: <CA+=Sn1=s_vkt=iJXHCn3oLEMv-0=2o5Q3EWvujLox-NGMAK6=g@mail.gmail.com>
On 2020-02-05, Andrew Pinski wrote:
>On Wed, Feb 5, 2020@1:10 AM Andrew Pinski <pinskia@gmail.com> wrote:
>>
>> On Wed, Feb 5, 2020@1:04 AM Andrew Pinski <pinskia@gmail.com> wrote:
>> >
>> > On Wed, Feb 5, 2020@12:59 AM Andrew Pinski <pinskia@gmail.com> wrote:
>> > >
>> > > On Tue, Feb 4, 2020@11:20 PM Fangrui Song <i@maskray.me> wrote:
>> > > >
>> > > > R_MIPS_PC32 exists as a GNU extension.
>> > > > R_MIPS_PC64 existed, but was removed by https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=4030e8f62467c29b782aa2480e1e452b8e458699
>> > > > (like all the old commits, the description just recorded what the commit *did*. There was no *why*.)
>> > >
>> > > But the why is recorded still in the mail archives:
>> > > https://sourceware.org/ml/binutils/2004-04/msg00657.html
>> >
>> > See the GCC side of the reason:
>> > https://gcc.gnu.org/ml/gcc-patches/2004-04/msg01093.html
>>
>> Note the reason why R_MIPS_PC32 was added back is described here:
>> https://sourceware.org/ml/binutils/2004-06/msg00213.html
>>
>> So it is a GNU extension as GCC accidentally emitted them so it needed
>> to be added back.
>
>
>> * DW_EH_PE_pcrel|DW_EH_PE_sdata8 => ?
>Never used on MIPS, see
>https://gcc.gnu.org/ml/gcc-patches/2004-06/msg00970.html
>Plus:
>https://www.sourceware.org/ml/binutils/2004-05/msg00227.html
>
>>
>>
>> Thanks,
>> Andrew
>>
>> >
>> >
>> > Thanks,
>> > Andrew Pinski
>> >
>> > >
>> > > Thanks,
>> > > Andrew Pinski
>> > >
>> > >
>> > > >
>> > > > This just makes certain things unnecessarily complex.
>> > > >
>> > > > * DW_EH_PE_pcrel|DW_EH_PE_sdata8 => ?
>> > > > * __patchable_function_entries has to have the SHF_WRITE flag on MIPS https://gcc.gnu.org/ml/gcc/2020-01/msg00106.html
>> > > > .quad foo - . => Error: PC-relative reference to a different section
I hope someone can add back R_MIPS_PC64.
I don't have any take on MIPS. I just feel that MIPS64 makes other
64-bit architectures inconvenient due to its own deficiency.
next prev parent reply other threads:[~2020-02-08 18:40 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-05 7:19 Fangrui Song
2020-02-05 9:00 ` Andrew Pinski
2020-02-05 9:04 ` Andrew Pinski
2020-02-05 9:10 ` Andrew Pinski
2020-02-05 9:16 ` Andrew Pinski
2020-02-08 18:40 ` Fangrui Song [this message]
2020-02-17 18:07 ` Maciej W. Rozycki
2020-02-19 4:26 ` Fangrui Song
2020-07-09 5:23 ` Fangrui Song
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