[Bug go/79037] gccgo: Binaries crash with parforsetup: pos is not aligned on m68k

[ian at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79037

--- Comment #14 from ian at gcc dot gnu.org <ian at gcc dot gnu.org> ---
Author: ian
Date: Wed Feb  1 23:35:59 2017
New Revision: 245110

URL: https://gcc.gnu.org/viewcvs?rev=245110&root=gcc&view=rev
Log:
        PR go/79037
    Backport from mainline:

    compiler, runtime: align gc data for m68k

    The current GC requires that the gc data be aligned to at least a 4
    byte boundary, because it uses the lower two bits of the address for
    flags (see LOOP and PRECISE in runtime/mgc0.c).  As the gc data is
    stored as a [...]uintptr, that is normally always true.  However, on
    m68k, that only guarantees 2 byte alignment.  Fix it by forcing the
    alignment.

    The parfor code used by the current GC requires that the parfor data
    be aligned to at least an 8 byte boundary.  The code in parfor.c
    verifies this.  This is normally true, as the data uses uint64_t
    values, but, again, this must be enforced explicitly on m68k.

    Fixes GCC PR 79037.

    Change-Id: Ifdf422db7b37e88f490e54c2f6d249117d359dd6

Modified:
    branches/gcc-6-branch/gcc/go/gofrontend/types.cc
    branches/gcc-6-branch/libgo/runtime/go-unsafe-pointer.c
    branches/gcc-6-branch/libgo/runtime/parfor.c
    branches/gcc-6-branch/libgo/runtime/runtime.h