From: Andre McCurdy <armccurdy@gmail.com>
To: Khem Raj <raj.khem@gmail.com>
Cc: musl@lists.openwall.com
Subject: Re: [PATCH] arm: avoid conditional branch to PLT in sigsetjmp.s
Date: Wed, 18 Sep 2019 10:52:13 -0700 [thread overview]
Message-ID: <CAJ86T=UMe46n1F1fLuu=D4twpr+S3kexmSoo9LLvtWmK0dEJWg@mail.gmail.com> (raw)
In-Reply-To: <CAMKF1srDwhkx++8WOKwtsu8NSwHXkA-29_wf0=yAe8o5Y=dUuw@mail.gmail.com>
On Wed, Sep 18, 2019 at 7:29 AM Khem Raj <raj.khem@gmail.com> wrote:
> On Tue, Sep 17, 2019 at 11:04 PM Andre McCurdy <armccurdy@gmail.com> wrote:
> >
> > The R_ARM_THM_JUMP19 relocation type generated for the original code
> > when targeting Thumb 2 is not supported by the gold linker:
> >
> > | .../arm-oe-linux-musleabi/9.2.0/ld: error: conditional branch to PLT in THUMB-2 not supported yet.
> > | src/signal/arm/sigsetjmp.s:9: error: unexpected opcode while processing relocation R_ARM_THM_JUMP19
>
> if it is thumb2 specific another option could be to use `it eq` before
> beq which should turn branch into an unconditional branch, which then
> uses R_ARM_THM_JUMP24 relocation that has a range of 16MB.
That would work too. Thumb 2 specific code would need to be guarded by
#ifdef __thumb2__ though (which I think implies also renaming the file
from .s to .S ?) and I'm not sure if the extra complexity justifies
saving one instruction in the ARM case.
next prev parent reply other threads:[~2019-09-18 17:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-18 6:04 Andre McCurdy
2019-09-18 14:28 ` Khem Raj
2019-09-18 17:52 ` Andre McCurdy [this message]
2019-09-18 19:54 ` Rich Felker
2019-11-21 20:54 ` Andre McCurdy
2019-12-07 18:03 ` Rich Felker
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