Subject: Re: The ELF ABI issue
To: None <Richard.Earnshaw@arm.com>
From: Jason R Thorpe <firstname.lastname@example.org>
Date: 03/26/2002 10:33:13
On Tue, Mar 26, 2002 at 10:01:45AM +0000, Richard Earnshaw wrote:
> No, disastrous.
We can skip the TLS register if we're going to call this ABI temporary...
> The ABI doesn't mandate any particular register for the PIC register -- it
> can be any register you like; it can even be different in each function
> you have. GCC only uses a fixed register because there are "bugs" in the
> compiler which mean that it can allocate a different register in each
> function properly for this purpose (it would be better if this could be
> fixed, but I'm not sure precisely where the problems are).
Ah, I see.
> The TLS register, on the other hand must be fixed (since the value is
> persistent across the whole thread). If you pick r8 then you will
> fragment the register ranges, particularly when not inside a shared
> library. There are different reasons why r9 or r10 might be the best
> choice, but r8 certainly would be a bad choice.
Ah, okay. Chris Gilbert suggested r11 to me after I posted my message.
-- Jason R. Thorpe <email@example.com>