[Bug go/66870] split stack issues on ppc64le and ppc64

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66870

--- Comment #33 from boger at gcc dot gnu.org ---
Author: boger
Date: Wed Oct 28 16:00:46 2015
New Revision: 229493

URL: https://gcc.gnu.org/viewcvs?rev=229493&root=gcc&view=rev
Log:
Backport of r229009

PR66870 PowerPC64 Enable gold linker with split stack

A powerpc-linux/powerpc64-linux biarch compiler can default to either
-m32 or -m64, and we need to notice both -m32 and -m64 on the gccgo
command line.  It's also possible to build a -m64 only compiler, so in
that case we can define TARGET_CAN_SPLIT_STACK.

gcc/
        PR go/66870
        * config/rs6000/sysv4.h (TARGET_CAN_SPLIT_STACK_64BIT): Don't define.
        * config/rs6000/linux64.h (TARGET_CAN_SPLIT_STACK): Define.
        (TARGET_CAN_SPLIT_STACK_64BIT): Define.
gcc/go/
        PR go/66870
        * gospec.c (saw_opt_m32): Rename to..
        (is_m64): ..this, initialised by TARGET_CAN_SPLIT_STACK_64BIT.
        Update uses.
        (lang_specific_driver): Set is_m64 if OPT_m64, clear if OPT_m32. 

Modified:
    branches/ibm/gcc-5-branch/gcc/config/rs6000/linux64.h
    branches/ibm/gcc-5-branch/gcc/config/rs6000/sysv4.h
    branches/ibm/gcc-5-branch/gcc/go/gospec.c