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

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
6.0.0 (branches/release_60 r321788). Upstream has branched for the
6.0.0 release, which should be in about 6 weeks. 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: 3 months

Upgrade our copies of clang, llvm, lldb and compiler-rt to r311606 from
the upstream release_50 branch.

As of this version, lib/msun's trig test should also work correctly
again (see bug 220989 for more information).

PR: 220989
MFC after: 2 months
X-MFC-with: r321369

Upgrade our copies of clang, llvm, lld and lldb to r309439 from the
upstream release_50 branch. This is just after upstream's 5.0.0-rc1.

MFC after: 2 months
X-MFC-with: r321369

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 3.6.0 release.

Please note that from 3.5.0 onwards, clang/llvm/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/3.6.0/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.6.0/tools/clang/docs/ReleaseNotes.html>

Thanks to Ed Maste for the lldb part of this upgrade.

Exp-run: antoine

Upgrade our copy of llvm/clang to 3.4 release. This version supports
all of the features in the current working draft of the upcoming C++
standard, provisionally named C++1y.

The code generator's performance is greatly increased, and the loop
auto-vectorizer is now enabled at -Os and -O2 in addition to -O3. The
PowerPC backend has made several major improvements to code generation
quality and compile time, and the X86, SPARC, ARM32, Aarch64 and SystemZ
backends have all seen major feature work.

Release notes for llvm and clang can be found here:
<http://llvm.org/releases/3.4/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.4/tools/clang/docs/ReleaseNotes.html>

MFC after: 1 month

Upgrade our copy of llvm/clang to trunk r178860, in preparation of the
upcoming 3.3 release (branching and freezing expected in a few weeks).

Preliminary release notes can be found at the usual location:
<http://llvm.org/docs/ReleaseNotes.html>

An MFC is planned once the actual 3.3 release is finished.

Upgrade our copy of llvm/clang to r168974, from upstream's release_32
branch. This is effectively llvm/clang 3.2 RC2; the 3.2 release is
coming soon.

Upgrade our copy of llvm/clang to trunk r154661, in preparation of the
upcoming 3.1 release (expected in a few weeks). Preliminary release
notes can be found at: <http://llvm.org/docs/ReleaseNotes.html>

MFC after: 2 weeks

Vendor import of clang trunk r154661:
http://llvm.org/svn/llvm-project/cfe/trunk@r154661