MFC r355940:

Move all sources from the llvm project into contrib/llvm-project.

This uses the new layout of the upstream repository, which was recently
migrated to GitHub, and converted into a "monorepo". That is, most of
the earlier separate sub-projects with their own branches and tags were
consolidated into one top-level directory, and are now branched and
tagged together.

Updating the vendor area to match this layout is next.

Move all sources from the llvm project into contrib/llvm-project.

This uses the new layout of the upstream repository, which was recently
migrated to GitHub, and converted into a "monorepo". That is, most of
the earlier separate sub-projects with their own branches and tags were
consolidated into one top-level directory, and are now branched and
tagged together.

Updating the vendor area to match this layout is next.

Merge llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and openmp
9.0.0 final release r372316.

Release notes for llvm, clang, lld and libc++ 9.0.0 are available here:

https://releases.llvm.org/9.0.0/docs/ReleaseNotes.html
https://releases.llvm.org/9.0.0/tools/clang/docs/ReleaseNotes.html
https://releases.llvm.org/9.0.0/tools/lld/docs/ReleaseNotes.html
https://releases.llvm.org/9.0.0/projects/libcxx/docs/ReleaseNotes.html

PR: 240629
MFC after: 1 month

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
the upstream release_70 branch r348686 (effectively, 7.0.1 rc3). The
release will follow very soon, but no more functional changes are
expected.

Release notes for llvm, clang and lld 7.0.0 are available here:
<http://releases.llvm.org/7.0.0/docs/ReleaseNotes.html>
<http://releases.llvm.org/7.0.0/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/7.0.0/tools/lld/docs/ReleaseNotes.html>

PR: 230240, 230355
Relnotes: yes
MFC after: 2 months

Pull in r327101 from upstream llvm trunk (by Rafael Espindola):

Don't treat .symver as a regular alias definition.

This patch starts simplifying the handling of .symver.

For now it just moves the responsibility for creating an alias down to
the streamer. With that the asm streamer can pass a .symver unchanged,
which is nice since gas cannot parse "foo@bar = zed".

In a followup I hope to move the handling down to the writer so that
we don't need special hacks for avoiding breaking names with @@@ on
windows.

Pull in r327160 from upstream llvm trunk (by Rafael Espindola):

Delay creating an alias for @@@.

With this we only create an alias for @@@ once we know if it should
use @ or @@. This avoids last minutes renames and hacks to handle MS
names.

This only handles the ELF writer. LTO still has issues with @@@
aliases.

Pull in r327928 from upstream llvm trunk (by Vitaly Buka):

Object: Move attribute calculation into RecordStreamer. NFC

Summary: Preparation for D44274

Reviewers: pcc, espindola

Subscribers: hiraditya

Differential Revision: https://reviews.llvm.org/D44276

Pull in r327930 from upstream llvm trunk (by Vitaly Buka):

Object: Fix handling of @@@ in .symver directive

Summary:
name@@@nodename is going to be replaced with name@@nodename if symbols is
defined in the assembled file, or name@nodename if undefined.
https://sourceware.org/binutils/docs/as/Symver.html

Fixes PR36623

Reviewers: pcc, espindola

Subscribers: mehdi_amini, hiraditya

Differential Revision: https://reviews.llvm.org/D44274

Together, these changes fix handling of @@@ in .symver directives when
doing Link Time Optimization.

Reported by: Shawn Webb <shawn.webb@hardenedbsd.org>
MFC after: 3 months
X-MFC-With: r327952

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
5.0.0 (trunk r308421). Upstream has branched for the 5.0.0 release,
which should be in about a month. Please report bugs and regressions,
so we can get them into the release.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

MFC after: 2 months

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
4.0.0 (branches/release_40 296509). The release will follow soon.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

Also note that as of 4.0.0, lld should be able to link the base system
on amd64 and aarch64. See the WITH_LLD_IS_LLD setting in src.conf(5).
Though please be aware that this is work in progress.

Release notes for llvm, clang and lld will be available here:
<http://releases.llvm.org/4.0.0/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/lld/docs/ReleaseNotes.html>

Thanks to Ed Maste, Jan Beich, Antoine Brodin and Eric Fiselier for
their help.

Relnotes: yes
Exp-run: antoine
PR: 215969, 216008
MFC after: 1 month

Upgrade our copies of clang, llvm, lldb, compiler-rt and libc++ to 3.9.0
release, and add lld 3.9.0. Also completely revamp the build system for
clang, llvm, lldb and their related tools.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

Release notes for llvm, clang and lld are available here:
<http://llvm.org/releases/3.9.0/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.9.0/tools/clang/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.9.0/tools/lld/docs/ReleaseNotes.html>

Thanks to Ed Maste, Bryan Drewery, Andrew Turner, Antoine Brodin and Jan
Beich for their help.

Relnotes: yes
MFC after: 1 month

Upgrade our copies of clang, llvm, lldb, compiler-rt and libc++ to 3.7.0
release.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

Release notes for llvm and clang can be found here:
<http://llvm.org/releases/3.7.0/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.7.0/tools/clang/docs/ReleaseNotes.html>

Thanks to Ed Maste, Andrew Turner and Antoine Brodin for their help.

Exp-run: antoine
Relnotes: yes

Upgrade our copy of clang, llvm and lldb to 3.5.0 release.

Please note that this version now requires C++11 support to build; see
UPDATING for more information.

Release notes for llvm and clang can be found here:
<http://llvm.org/releases/3.5.0/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.5.0/tools/clang/docs/ReleaseNotes.html>

Thanks to Ed Maste, Roman Divacky, Andrew Turner, Justin Hibbits and
Antoine Brodin for their invaluable help with this import.

Approved by: portmgr (antoine)
MFC after: 1 month

Merge llvm 3.5.0 release from ^/vendor/llvm/dist, resolve conflicts, and
preserve our customizations, where necessary.

Vendor import of llvm RELEASE_350/final tag r216957 (effectively, 3.5.0 release):
https://llvm.org/svn/llvm-project/llvm/tags/RELEASE_350/final@216957