Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r262613:

Merge the projects/clang-sparc64 branch back to head. This brings in
several updates from the llvm and clang trunks to make the sparc64
backend fully functional.

Apart from one patch to sys/sparc64/include/pcpu.h which is still under
discussion, this makes it possible to let clang fully build world and
kernel for sparc64.

Any assistance with testing this on actual sparc64 hardware is greatly
appreciated, as there will unavoidably be bugs left.

Many thanks go to Roman Divacky for his upstream work on getting the
sparc64 backend into shape.

MFC r262985:

Repair a few minor mismerges from r262261 in the clang-sparc64 project
branch. This is also to minimize differences with upstream.

Merge the projects/clang-sparc64 branch back to head. This brings in
several updates from the llvm and clang trunks to make the sparc64
backend fully functional.

Apart from one patch to sys/sparc64/include/pcpu.h which is still under
discussion, this makes it possible to let clang fully build world and
kernel for sparc64.

Any assistance with testing this on actual sparc64 hardware is greatly
appreciated, as there will unavoidably be bugs left.

Many thanks go to Roman Divacky for his upstream work on getting the
sparc64 backend into shape.

MFC after: 1 month

Import a whole bunch of llvm trunk commits to enable self-hosting clang
3.4 on Sparc64 (commit descriptions left out for brevity):

r196755 r198028 r198029 r198030 r198145 r198149 r198157 r198565 r199186
r199187 r198280 r198281 r198286 r198480 r198484 r198533 r198567 r198580
r198591 r198592 r198658 r198681 r198738 r198739 r198740 r198893 r198909
r198910 r199014 r199024 r199028 r199031 r199033 r199061 r199775 r199781
r199786 r199940 r199974 r199975 r199977 r200103 r200104 r200112 r200130
r200131 r200141 r200282 r200368 r200373 r200376 r200509 r200617 r200960
r200961 r200962 r200963 r200965

Submitted by: rdivacky