Re: patch for exception handlers in PIC code on ARM

[Richard Earnshaw <rearnsha at arm dot com>]

> [ You seem to only have send the mail to me.  But since you are
>   also talking to Phil it is clear you didn't mean to.  So I've
>   quoted the text in its entirety in cc'ing it back to gcc-patches.  ]
> 

No, I sent the mail to everyone.  I suspect your machine isn't properly 
displaying multiple cc lines.  This issue has come up before, and think it 
was concluded that it can also be due to a buggy sendmail somewhere.

> > I haven't had chance to look at the code yet, but I'd be surprised if they 
> > got it right for the ARM's hardware floating point registers. Special 
> > non-trapping instructions have to be used for this (sfm/lfm or stfe/ldfe 
> > in some compilation variants), and currently only the prologue and 
> > epilogue code know what to do.  Also longjmp will have to know how to 
> > switch to/from Thumb mode in some variants.
> 
> But that's exactly why things are done the way they are.
> 
> __builtin_longjmp doesn't touch anything it doesn't have to; all saving
> and restoring of registers is done by the prologue and epilogue code of
> the routine containing the __builtin_setjmp.

As I said, I haven't had chance to investigate yet; if it does DTRT, then 
great.

R.