Pavel added an extension to lldb's gdb remote serial protocol that
allows the debug stub to append an error message (ascii hex encoded)
after an error response packet Exx. This was added in 2017 in
https://reviews.llvm.org/D34945 . lldb sends the
QErrorStringInPacketSupported packet and then the remote stub may add
these error strings.

debugserver has two bugs in its use of extended error messages: the
vAttach family would send the extended error string without checking if
the mode had been enabled. And qLaunchSuccess would not properly format
its error response packet (missing the hex digits, did not asciihex
encode the string).

There is also a bug in the HandlePacket_D (detach) packet where the
error packets did not include hex digits, but this one does not append
an error string.

I'm adding a new RNBRemote::SendErrorPacket() and routing all error
packet returns though this one method. It takes an optional second
string which is the longer error message; it now handles appending it to
the Exx response or not, depending on the QErrorStringInPacketSupported
state. I updated all packets to send their errors via this method.

According to

https://riscv-optimization-guide-riseproject-c94355ae3e6872252baa952524.gitlab.io/riscv-optimization-guide.html:

> The v0 register defined by the RISC-V vector extension is special in
> that it can be used both as a general purpose vector register and also
> as a mask register. As a preference, use registers other than v0 for
> non-mask values. Otherwise data will have to be moved out of v0 when a
> mask is required in an operation. v0 may be used when all other
> registers are in use, and using v0 would avoid spilling register state
> to memory.

And using V0 register may stall masking pipeline and stop chaining
for some microarchitectures.

So we should try to not use V0 and register groups contained it as
much as possible. We achieve this via moving V0 to the end of RA
order.

Currently, `libc` fails when building on redhat because the triple
format uses `redhat` instead of `linux` (The same problem as openSUSE).
This PR changes `libc` to accept `redhat` as a valid Linux triple.

---------

Co-authored-by: Joseph Huber <huberjn@outlook.com>

This reverts commit 3434472e.

Closes #43097.

SetThreadDescription symbol needs to be dynamically loaded before usage.
Then using a wide string buffer, since we re using a null terminated
string, we can use MultiByteToWideChar -1 as 4th argument to finally set
the thread name.

Previously `SetThreadDescription` was called directly causing crash.
It was reverted in dd3aa26f

This reverts commit 9a12b0a6.

TestAddressMasks fails its first test on lldb-x86_64-debian,
lldb-arm-ubuntu, lldb-aarch64-ubuntu bots.  Reverting while
investigating.

I'm reviving a patch from phabracator, https://reviews.llvm.org/D155905
which was approved but I wasn't thrilled with all the API I was adding
to SBProcess for all of the address mask types / memory regions. In this
update, I added enums to control type address mask type (code, data,
any) and address space specifiers (low, high, all) with defaulted
arguments for the most common case.

This patch is also fixing a bug in the "addressable bits to address
mask" calculation I added in AddressableBits::SetProcessMasks. If lldb
were told that 64 bits are valid for addressing, this method would
overflow the calculation and set an invalid mask. Added tests to check
this specific bug while I was adding these APIs.

rdar://123530562

Continuous efforts #83357. Previously reverted #83377.

Supports TLS local-dynamic on AIX, generates below sequence of code:

```
.tc foo[TC],foo[TL]@ld # Variable offset, ld relocation specifier
.tc mh[TC],mh[TC]@ml # Module handle for the caller
lwz 3,mh[TC]\(2\) $$ For 64-bit: ld 3,mh[TC]\(2\)
bla .__tls_get_mod # Modifies r0,r3,r4,r5,r11,lr,cr0
#r3 = &TLS for module
lwz 4,foo[TC]\(2\) $$ For 64-bit: ld 4,foo[TC]\(2\)
add 5,3,4 # Compute &foo
.rename mh[TC], "\_$TLSML" # Symbol for the module handle must have the name "_$TLSML"
```

---------

Co-authored-by: tingwang <tingwang@tingwangs-MBP.lan>
Co-authored-by: tingwang <tingwang@tingwangs-MacBook-Pro.local>

[libc++] Set feature test macros __cpp_lib_ranges_contains and__cpp_lib_ranges_starts_ends_with (#81816)

ranges::contains: fdd089b5
ranges::starts_with: 20517557
ranges::ends_with: 0218ea4a



Co-authored-by: Louis Dionne <ldionne.2@gmail.com>

When expand `select_cc` in finalize-isel, we should not generate `isel`
for targets not feature it.

Simpler code, compared to tracking state of 2 variables and the ambiguity of "0" CountValue (is it 0 or is it invalid?)

Windows folds to 1.01563 and linux to 1.01562, let's just check the prefix here.

Don't use multiple tagged pages at the beginning of an allocation, since
it prevents using such allocations for memrefs, and mappings aren't
reused anyway since Trusty uses MapAllocatorNoCache.
Upstreamed from https://r.android.com/2537251

.

Co-authored-by: Marco Nelissen <marcone@google.com>

Reverts llvm/llvm-project#83377

The test does not pass on the bot.

Inspect a basic block and if its single basic block loop with a small
number of instructions, set the Loop Alignment to 32 bytes. This will
avoid the cache line break in the first packet of loop which will cause
a stall per each execution of loop.

Fix race condition when multiple instances of `llvm-progen` read from
the same inputs.

For `LDBL_MANT_DIG == 113` targets the REAL(16) versions of F18
runtime APIs can stay and should better stay in FortranRuntime.
This way, no additional linking actions are required, because
glibc provides all that is needed.
I thought I would isolate all REAL(16) implementations (both
via `__float128` and `long double`) into Float128Math library,
but that was a bad idea.

This should fix aarch64 buildbots failing gfortran tests.

Remove LSH transform and restore previous lowering.

Fixes conformance issue in
[77615](https://github.com/llvm/llvm-project/pull/77615

) where OpenCL
integer_ops tests fail for integer_clz.

Co-authored-by: Leon Clark <leoclark@amd.com>

Many profitable optimizations cannot be performed at -Oz, due to
unrotated loops. While this is worse for size (minimally), many of the
optimizations significantly reduce code size, such as memcpy
optimizations and other patterns found by loop idiom recognition.
Related discussion can be found in issue #50308.

This patch adds an experimental, backend-only flag to allow loop header
duplication, regardless of the optimization level. Downstream consumers
can experiment with this flag, and if it is profitable, we can adjust
the compiler's defaults accordingly, and expose any useful frontend
flags to opt into the new behavior.

Layout information for a record gets stored in the `ClangASTImporter`
associated with the `DWARFASTParserClang` that originally parsed the
record. LLDB sometimes moves clang types from one AST to another (in the
reproducer the origin AST was a precompiled-header and the destination
was the AST backing the executable). When clang then asks LLDB to
`layoutRecordType`, it will do so with the help of the
`ClangASTImporter` the type is associated with. If the type's origin is
actually in a different LLDB module (and thus a different
`DWARFASTParserClang` was used to set its layout info), we won't find
the layout info in our local `ClangASTImporter`.

In the reproducer this meant we would drop the alignment info of the
origin type and misread a variable's contents with `frame var` and
`expr`.

There is logic in `ClangASTSource::layoutRecordType` to import an
origin's layout info. This patch re-uses that infrastructure to import
an origin's layout from one `ClangASTImporter` instance to another.

rdar://123274144

This seemed like relevant information to include in the code of conduct.

This patch moves the logic for copying the layout info of a
`RecordDecl`s origin into a target AST.

A follow-up patch re-uses the logic from within the `ClangASTImporter`,
so the natural choice was to move it there.

The test added by PR81322 didn't actually check the coldness of the
attributes being matched on the IR. Add that checking.

This reverts commit cff36bb1.

This patch was causing build failures in certain configurations.

This reverts commit c66f2d0c.

The bot is broken.

The timeout for this test was set to 1.0s which is very low, it should
be a default of 10s and be increased by a factor of 10 if ASAN is
enabled. This will help reduce the falkiness of the test, especially in
ASAN builds.

_LIBCPP_ASSERT_SHIM used by the -fno-exceptions and 
LIBCXX_ENABLE_NEW_DELETE_DEFINITIONS=on configuration
needs _LIBCPP_ASSERT from <__assert>.

Add the [[maybe_unused]] attribute to a variable in
lib/Lower/OpenMP/OpenMP.cpp to avoid a (possibly bogus) unused variable
warning when building with GCC 9.3.0.

Umbrella bug #83182

Instance of DenseMap were copied into local variable,
and as a result reference to string stored in that local
variable were returned from function. At the end fix-it
were applied with already destroyed string causing some
non utf-8 characters to be printed.

Related to #80541

This patch adds a std::string_view conversion to SmallString which we've
recently found a use for downstream in a project that is using c++
standard library IO.

Umbrella bug #83182