Merge llvm-project main llvmorg-17-init-19304-gd0b54bb50e51

This updates llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and
openmp to llvm-project main llvmorg-17-init-19304-gd0b54bb50e51, the
last commit before the upstream release/17.x branch was created.

PR: 273753
MFC after: 1 month

Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

Move LIBADD lines from usr.bin/clang/*/Makefile one level up

Some utilities under usr.bin/clang were only linked to libz, while most
others were linked to libz and libzstd. Make this consistent, and remove
repetition, by moving these LIBADD lines to usr.bin/clang/clang.prog.mk
and usr.bin/clang/clang.prog.mk.

MFC after: 3 days

Merge llvm-project main llvmorg-16-init-18548-gb0daacf58f41

This updates llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and
openmp to llvmorg-16-init-18548-gb0daacf58f41.

PR: 271047
MFC after: 1 month

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.

Completely revamp the way llvm, clang and lldb are built.

* Bootstrap llvm-tblgen and clang-tblgen with a minimal llvm static
library, that has no other dependencies.
* Roll up all separate llvm libraries into one big static libllvm.
* Similar for all separate clang and lldb static libraries.
* For all these libraries, generate their .inc files only once.
* Link all llvm tools (including extra) against the big libllvm.
* Link clang and clang-format against the big libllvm and libclang.
* Link lldb against the big libllvm, libclang and liblldb.

N.B.: This is work in progress, some details may still be missing.

It also heavily depends on bsd.*.mk's support for SRCS and DPSRCS with
relative pathnames, which apparently does not always work as expected.
For building llvm, clang and lldb though, it seems to work just fine.

The main idea behind this restructuring is maintainability and build
peformance. The previous large number of very small libraries, each
with their own generated files and dependencies was slow to traverse
and hard to understand.

Possible future improvements:
* Only build certain targets, e.g. for most regular users having just
one target will be fine. This will shave off some build time.
* Building the big llvm, clang and lldb libraries as shared (private)
libraries.
* Adding other components from the LLVM project, such as lld.

Update build glue for clang and the llvm/clang extras.

Some additional llvm tools need libz. While here, consistently use
LIBADD+=.

Next part of updating llvm/clang build glue: getting the
WITH_CLANG_EXTRAS tools built.

Add the llvm-cov and llvm-profdata tools, when WITH_CLANG_EXTRAS is
defined. These help with processing coverage and profile data.

Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

Move LIBADD lines from usr.bin/clang/*/Makefile one level up

Some utilities under usr.bin/clang were only linked to libz, while most
others were linked to libz and libzstd. Make this consistent, and remove
repetition, by moving these LIBADD lines to usr.bin/clang/clang.prog.mk
and usr.bin/clang/clang.prog.mk.

MFC after: 3 days

Merge llvm-project main llvmorg-16-init-18548-gb0daacf58f41

This updates llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and
openmp to llvmorg-16-init-18548-gb0daacf58f41.

PR: 271047
MFC after: 1 month

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.

Completely revamp the way llvm, clang and lldb are built.

* Bootstrap llvm-tblgen and clang-tblgen with a minimal llvm static
library, that has no other dependencies.
* Roll up all separate llvm libraries into one big static libllvm.
* Similar for all separate clang and lldb static libraries.
* For all these libraries, generate their .inc files only once.
* Link all llvm tools (including extra) against the big libllvm.
* Link clang and clang-format against the big libllvm and libclang.
* Link lldb against the big libllvm, libclang and liblldb.

N.B.: This is work in progress, some details may still be missing.

It also heavily depends on bsd.*.mk's support for SRCS and DPSRCS with
relative pathnames, which apparently does not always work as expected.
For building llvm, clang and lldb though, it seems to work just fine.

The main idea behind this restructuring is maintainability and build
peformance. The previous large number of very small libraries, each
with their own generated files and dependencies was slow to traverse
and hard to understand.

Possible future improvements:
* Only build certain targets, e.g. for most regular users having just
one target will be fine. This will shave off some build time.
* Building the big llvm, clang and lldb libraries as shared (private)
libraries.
* Adding other components from the LLVM project, such as lld.

Update build glue for clang and the llvm/clang extras.

Some additional llvm tools need libz. While here, consistently use
LIBADD+=.

Next part of updating llvm/clang build glue: getting the
WITH_CLANG_EXTRAS tools built.

Add the llvm-cov and llvm-profdata tools, when WITH_CLANG_EXTRAS is
defined. These help with processing coverage and profile data.

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.

Completely revamp the way llvm, clang and lldb are built.

* Bootstrap llvm-tblgen and clang-tblgen with a minimal llvm static
library, that has no other dependencies.
* Roll up all separate llvm libraries into one big static libllvm.
* Similar for all separate clang and lldb static libraries.
* For all these libraries, generate their .inc files only once.
* Link all llvm tools (including extra) against the big libllvm.
* Link clang and clang-format against the big libllvm and libclang.
* Link lldb against the big libllvm, libclang and liblldb.

N.B.: This is work in progress, some details may still be missing.

It also heavily depends on bsd.*.mk's support for SRCS and DPSRCS with
relative pathnames, which apparently does not always work as expected.
For building llvm, clang and lldb though, it seems to work just fine.

The main idea behind this restructuring is maintainability and build
peformance. The previous large number of very small libraries, each
with their own generated files and dependencies was slow to traverse
and hard to understand.

Possible future improvements:
* Only build certain targets, e.g. for most regular users having just
one target will be fine. This will shave off some build time.
* Building the big llvm, clang and lldb libraries as shared (private)
libraries.
* Adding other components from the LLVM project, such as lld.

Update build glue for clang and the llvm/clang extras.

Some additional llvm tools need libz. While here, consistently use
LIBADD+=.

Next part of updating llvm/clang build glue: getting the
WITH_CLANG_EXTRAS tools built.