[Bug driver/49371] xgcc: error: unrecognized option '-pie' on *-apple-darwin*

["iains at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49371

--- Comment #16 from Iain Sandoe <iains at gcc dot gnu.org> 2011-06-12 19:01:51 UTC ---
(In reply to comment #15)
> I have bootstrapped gcc on x86_64-apple-darwin10.7.0 with the patch in comment
> #14 and the tests for gcc and tls.exp pass without unexpected failure. I just
> noticed the following oddity:
> 
> [macbook] f90/bug% gfc -m64 -fpie -mdynamic-no-pic pr49331.f90 
> gfc: note: '-mdynamic-no-pic' overides '-pie', '-fpie' or '-fPIE'
> [macbook] f90/bug% gfc -m32 -fpie -mdynamic-no-pic pr49331.f90
> f951: warning: '-mdynamic-no-pic' overrides '-fpic', '-fPIC', '-fpie', '-fPIE'
> or '-pie' [enabled by default]
> gfc: note: '-mdynamic-no-pic' overides '-pie', '-fpie' or '-fPIE'
> [macbook] f90/bug% gcc47 -m64 -fpie -mdynamic-no-pic backtrace.c
> gcc47: note: '-mdynamic-no-pic' overides '-pie', '-fpie' or '-fPIE'
> [macbook] f90/bug% gcc47 -m32 -fpie -mdynamic-no-pic backtrace.c
> cc1: warning: '-mdynamic-no-pic' overrides '-fpic', '-fPIC', '-fpie', '-fPIE'
> or '-pie' [enabled by default]
> gcc47: note: '-mdynamic-no-pic' overides '-pie', '-fpie' or '-fPIE'

Those are correct - the options conflict [i.e. you can't have -pie and
-mdynamic-no-pic at the same time].

> Is it expected that the warning appears with -m32, but not with -m64? I also
> got

Yes, I guess so on x86, mdynamic-no-pic has no effect for m64 (x86) ... 
... I need to check what happens for m64 powerpc (but suspect it still
applies).

>  [macbook] f90/bug% gcc47 -m32 -fno-PIC -pie backtrace.c
> ld: cannot link -pie: -mdynamic-no-pic codegen found in _myfunc3 from
> /var/tmp//cccDWsse.o
> collect2: error: ld returned 1 exit status

Hmm.  That is an uncaught conflict, I think .. IIRC, pie requires position
independent code.. so something's not 100% right...  (perhaps there should be
an error from cc1 in that case).

thanks, as always for the checking - 
- don't know when/if I'll get a chance to look further at this .. so anyone
else is welcome to take my patchlet forward ...