Reviving SH FDPIC target

Segher Boessenkool segher@kernel.crashing.org
Fri Sep 4 23:08:00 GMT 2015


On Fri, Sep 04, 2015 at 04:16:40PM -0400, Rich Felker wrote:
> One thing I've noticed that's odd is that gcc -mfdpic -fPIC produces
> different (less efficient) code from just gcc -mfdpic, which seems
> wrong, but agrees with sh.c which has a number of checks for flag_pic
> not matched with a TARGET_FDPIC check.

Generic code tests flag_pic in important places as well.

> I'm thinking all of these
> should either be flag_pic||TARGET_PIC or flag_pic&&!TARGET_FDPIC,
> depending on whether the code applies to all PIC or is specific to the
> non-FDPIC PIC model where r12 is call-saved. Does this sound correct?
> I think we need spurious -fPIC to work (although it could be handled
> with spec magic) and not pessimize code, since most library builds
> will use -fPIC.

If you never want -fPIC (or -fpic) if fdpic is enabled, you can disable
it (in sh_option_override)?


Segher



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