Remove svn:mergeinfo carried over from stable/9.

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

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: r228919

Add locally implemented atomic intrinsics to libcompiler_rt.

The built-in atomic operations are not implemented in our version of GCC
4.2 for the ARM and MIPS architectures. Instead of emitting locked
instructions, they generate calls to functions that can be implemented
in the C runtime.

Only implement the atomic operations that are used by <stdatomic.h> for
datatype sizes that are supported by atomic(9). This means that on these
architectures, we can only use atomic operations on 32-bits and 64-bits
variables, which is typically sufficient.

This makes <stdatomic.h> work on all architectures except MIPS, since
MIPS still uses libgcc.

MFC: r229135

Upgrade libcompiler_rt to upstream revision 147390.

This version of libcompiler_rt adds support for __mulo[sdt]i4(), which
computes a multiply and its overflow flag. There are also a lot of
cleanup fixes to headers that don't really affect us.

Updating to this revision should make it a bit easier to contribute
changes back to the LLVM developers.

MFC: r235487

Switch sparc64 to using libcompiler_rt; since r230021 (MFC'ed to stable/9 in
r236012) we have a workaround in place allowing it to be used there and since
r235388 (MFC'ed to stable/9 in r236002) we also have usable div/mod
optimizations like libgcc has.

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Upgrade libcompiler_rt from revision 117047 to 132478.

It seems there have only been a small amount to the compiler-rt source
code in the mean time. I'd rather have the code in sync as much as
possible by the time we release 9.0. Changes:

- The libcompiler_rt library is now dual licensed under both the
University of Illinois "BSD-Like" license and the MIT license.

- Our local modifications for using .hidden instead of .private_extern
have been upstreamed, meaning our changes to lib/assembly.h can now be
reverted.

- A possible endless recursion in __modsi3() has been fixed.

- Support for ARM EABI has been added, but it has no effect on FreeBSD
(yet).

- The functions __udivmodsi4 and __divmodsi4 have been added.

Requested by: many, including bf@ and Pedro Giffuni

Mark libcompiler_rt as not needed executable stack on powerpc.

Reviewed and tested by: nwhitehorn

Fix braino in r217101. -Wa is used to supply assembler flag to cc driver.

Noted by: Anonymous <swell.k gmail com>

On amd64 and i386, force assembler to mark objects compiled from the
assembler source for libcompiler_rt as not needed executable stack. This
is done with a hammer instead of properly marking each assembly file
with section .note.GNU-stack to avoid modifying contributed source.

Discussed with: ed

Switch mips architectures back to libgcc.

MIPS64 n64 binaries are broken with libcompiler_rt at this time.
Switch mips back to libgcc until the cause of breakage is analyzed
and fixed.

Revert to libgcc for sparc64.

I've had a report of a sparc64 system where cc1 generates illegal
instructions. We still have to diagnose this properly, but instead of
hosing all sparc64 boxes out there, fall back to libgcc to prevent more
damage.

Reported by: Florian Smeets

Set symbol visibility to hidden.

Not doing so may cause all sorts of random libraries to expose
libcompiler_rt's functions, which should of course not be done.

Discussed with: kan, kib

Import libcompiler_rt into HEAD and add Makefiles.

Obtained from: user/ed/compiler-rt