x86-64 and large code model questions/bugs

[H.J. Lu]

On Wed, Jan 28, 2009 at 1:40 AM, Andi Kleen <andi@firstfloor.org> wrote:
> On Wed, Jan 28, 2009 at 10:21:16AM +0100, Paolo Bonzini wrote:
>> Andi Kleen wrote:
>> > On Wed, Jan 28, 2009 at 09:39:39AM +0100, Paolo Bonzini wrote:
>> >>> He'll get much better code by putting the program into a -fPIC .so,
>> >>> loading it from a small stub and then unmap the stub.
>> >>> large model generates really very bad code because all jumps
>> >>> will be indirect.
>> >> Is it also true with -fpie?
>> >
>> > Not sure what you mean?
>>
>> Right, sorry.  I meant "can you also use -fpie and use a linker script
>> to relocate the text section", if you want to place it high but the code
>> is not gigantic?
>
> That would require -fpie crt*
>
> Probably doable, but needs some more effort than just
> using a classical main() stub.
>

It works fine with the latest binutils from CVS:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38988#c4


-- 
H.J.