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_80 branch r355313 (effectively, 8.0.0 rc3). The
release will follow very soon, but no more functional changes are
expected.

Release notes for llvm, clang and lld 8.0.0 will soon be available here:
<https://releases.llvm.org/8.0.0/docs/ReleaseNotes.html>
<https://releases.llvm.org/8.0.0/tools/clang/docs/ReleaseNotes.html>
<https://releases.llvm.org/8.0.0/tools/lld/docs/ReleaseNotes.html>

PR: 236062
Relnotes: yes
MFC after: 1 month

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, 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

Update libc++ to 3.8.0. Excerpted list of fixes (with upstream revision
numbers):

r242679 Implement the plugin-based version of std::search. There are no
searchers yet; those are coming soon.
r242682 Implement the default searcher for std::experimental::search.
r243728 Add <experimental/any> v2.
r245330 implement more of N4258 - Cleaning up noexcept in the standard
library. Specifically add new noexcept stuff to vector and
string's move-assignment operations
r245334 Fix PR22606 - Leak pthread_key with static storage duration to
ensure all of thread-local destructors are called.
r245335 Fix PR23589: std::function doesn't recognize null pointer to
varargs function.
r247036 Implementation of Boyer-Moore and Boyer-Moore-Horspool
searchers for the LFTS.
r249325 Implement LWG#2063, and update the issues links to point to the
github generated pages
r249738 Split <ctype.h> out of <cctype>.
r249739 Split <errno.h> out of <cerrno>.
r249740 Split <float.h> out of <cfloat>.
r249741 Split <inttypes.h> out of <cinttypes>.
r249742 Split <math.h> out of <cmath>.
r249743 Split <setjmp.h> out of <csetjmp>.
r249761 Split <stddef.h> out of <cstddef>.
r249798 Split <stdio.h> out of <cstdio>.
r249800 Split <stdlib.h> out of <cstdlib>.
r249889 Split <wchar.h> out of <cwchar>.
r249890 Split <wctype.h> out of <cwctype>.
r249929 Split <string.h> out of <cstring>.
r250254 ABI versioning macros for libc++.
r251246 Fix LWG#2244: basic_istream::seekg
r251247 Fix LWG#2127: Move-construction with raw_storage_iterator.
r251253 Fix LWG#2476: scoped_allocator_adaptor is not assignable
r251257 Fix LWG#2489: mem_fn() should be noexcept
r251618 Implement P0004R1 'Remove Deprecated iostreams aliases'
r251766 Implement the first part of P0006R0: Adopt Type Traits Variable
Templates for C++17.
r252195 Implement P0092R1 for C++1z
r252350 Allow deque to handle incomplete types.
r252406 More of P0006R0: type traits variable aliases for C++17.
r252407 Implement LWG#2353: std::next is over-constrained
r252905 Implement P0074: Making owner_less more flexible
r253215 Implement P0013R1: Logical Operator Type Traits.
r253274 Implement P0007: Constant View: A proposal for a std::as_const
helper function template.
r254119 Add static_assert to set/multiset/map/multimap/forward_list/deque
that the allocator's value_type match the container's value_type.
r254283 Implement more of P0006; Type Traits Variable Templates.
r255941 LWG2485: get() should be overloaded for const tuple&&.
r256325 Fix LWG Issue #2367 - Fixing std::tuple and std::pair's default
constructors.
r256652 Fix for ALL undefined behavior in <list>.
r256859 First half of LWG#2354: 'Unnecessary copying when inserting
into maps with braced-init syntax'

Exp-run: antoine
Relnotes: yes

Since contrib/libc++'s ancestry was never correct, subversion 1.8 and
higher cannot merge to it from the vendor area.

Re-bootstrap the ancestry by doing (apologies to your retinas):
* svn rm contrib/libc++
* svn cp ^/vendor/libc++/dist@276792 contrib/libc++
* svn cp ^/head/contrib/libc++/FREEBSD-upgrade@287629 contrib/libc++
* svn cp ^/head/contrib/libc++/include/__bit_reference@287629 contrib/libc++/include
* svn cp ^/head/contrib/libc++/include/__config@287629 contrib/libc++/include
* svn cp ^/head/contrib/libc++/include/__tree@287629 contrib/libc++/include
* svn cp ^/head/contrib/libc++/include/algorithm@287629 contrib/libc++/include
* svn cp ^/head/contrib/libc++/include/stdexcept@287629 contrib/libc++/include
* svn cp ^/head/contrib/libc++/include/type_traits@287629 contrib/libc++/include
* svn pd -R svn:mergeinfo contrib/libc++
* svn ps -F mergeinfo.txt contrib/libc++

Vendor import of libc++ trunk r224926:
https://llvm.org/svn/llvm-project/libcxx/trunk@224926

Vendor import of libc++ tags/RELEASE_34/final r197960:
https://llvm.org/svn/llvm-project/libcxx/tags/RELEASE_34/final@197960

Vendor import of libc++ trunk r180598.

Pull new version of libc++ into vendor branch.

Vendor import of libc++ trunk r165949:
http://llvm.org/svn/llvm-project/libcxx/trunk@165949

Import new version of libc++ into vendor branch.

Approved by: dim (mentor)

Import libcxxrt / libc++ into a vendor branch.

Approved by: dim (mentor)