On 06/16/2014 07:26 PM, Mike Stump wrote:
On Jun 16, 2014, at 3:56 AM, Bernd Schmidt <ber...@codesourcery.com>
wrote:
For the ptx port, I've needed to write a new pass which ensures all
objects go into address spaces as required by the machine.
I have such a machine and I’ve always approached the problem from the
front end side. I ensure the right space up front, and if someone
doesn’t get the right space, I add code to let the port choose the
space for that object (literal constants I wanna play around with
some for example). On my port there is no changing spaces once one
is selected.
There are two reasons why I can't do this in the frontends - one, Joseph
has already rejected a C frontend patch, and two, this needs to work
with OpenACC offloading - i.e. code is initially compiled by an x86 host
compiler, then a ptx lto1 reads it in and needs to make it valid for
that target.
I’m curious if your port needs to change a space (and why, I’m
wondering if I can improve my port by changing spaces)?
No, address spaces are fixed for globals, locals, and rodata. But in the
early stages of the compiler, for the above reasons we need to pretend
that there aren't any address spaces involved, and only the
lower-addr-spaces pass moves everything to the right place.
Bernd
