This patch removes all of the Set.* methods from Status.

This cleanup is part of a series of patches that make it harder use the
anti-pattern of keeping a long-lives Status object around and updating
it while dropping any errors it contains on the floor.

This patch is largely NFC, the more interesting next steps this enables
is to:
1. remove Status.Clear()
2. assert that Status::operator=() never overwrites an error
3. remove Status::operator=()

Note that step (2) will bring 90% of the benefits for users, and step
(3) will dramatically clean up the error handling code in various
places. In the end my goal is to convert all APIs that are of the form

`    ResultTy DoFoo(Status& error)
`
to

`    llvm::Expected<ResultTy> DoFoo()
`
How to read this patch?

The interesting changes are in Status.h and Status.cpp, all other
changes are mostly

` perl -pi -e 's/\.SetErrorString/ = Status::FromErrorString/g' $(git
grep -l SetErrorString lldb/source)
`
plus the occasional manual cleanup.

Previously lldb was using arrays of size kMaxRegisterByteSize to handle
registers. This was set to 256 because the largest possible register
we support is Arm's scalable vectors (SVE) which can be up to 256 bytes long.

This means for most operations aside from SVE, we're wasting 192 bytes
of it. Which is ok given that we don't have to pay the cost of a heap
alocation and 256 bytes isn't all that much overall.

With the introduction of the Arm Scalable Matrix extension there is a new
array storage register, ZA. This register is essentially a square made up of
SVE vectors. Therefore ZA could be up to 64kb in size.

https://developer.arm.com/documentation/ddi0616/latest/

"The Effective Streaming SVE vector length, SVL, is a power of two in the range 128 to 2048 bits inclusive."

"The ZA storage is architectural register state consisting of a two-dimensional ZA array of [SVLB × SVLB] bytes."

99% of operations will never touch ZA and making every stack frame 64kb+ just
for that slim chance is a bad idea.

Instead I'm switching register handling to use SmallVector with a stack allocation
size of kTypicalRegisterByteSize. kMaxRegisterByteSize will be used in places
where we can't predict the size of register we're reading (in the GDB remote client).

The result is that the 99% of small register operations can use the stack
as before and the actual ZA operations will move to the heap as needed.

I tested this by first working out -wframe-larger-than values for all the
libraries using the arrays previously. With this change I was able to increase
kMaxRegisterByteSize to 256*256 without hitting those limits. With the
exception of the GDB server which needs to use a max size buffer.

Reviewed By: JDevlieghere

Differential Revision: https://reviews.llvm.org/D153626

No one was pasing nullptr here.

Depends on D135670

Reviewed By: clayborg

Differential Revision: https://reviews.llvm.org/D135671

Most of the paths to this never passed nullptr intentionally. Those
that possibly could have were assuming it was not null elsehwere,
so would have crashed.

I've added asserts in those cases.

At least one case was relying on GetAsMemoryData to return an error
when it was given nullptr. So I've hoisted that error setting code
out into the caller.

Depends on D134963

Reviewed By: clayborg

Differential Revision: https://reviews.llvm.org/D134965

Currently, lldb-server was opening the executable file to determine the
process architecture (to differentiate between 32 and 64 bit
architecture flavours). This isn't a particularly trustworthy source of
information (the file could have been changed since the process was
started) and it is not always available (file could be deleted or
otherwise inaccessible).

Unfortunately, ptrace does not give us a direct API to access the
process architecture, but we can still infer it via some of its
responses -- given that the general purpose register set of 64-bit
applications is larger [citation needed] than the GPR set of 32-bit
ones, we can just ask for the application GPR set and check its size.

This is what this patch does.

Differential Revision: https://reviews.llvm.org/D130985

Differential Revision: https://reviews.llvm.org/D90119

Summary:
A *.cpp file header in LLDB (and in LLDB) should like this:
```
//===-- TestUtilities.cpp -------------------------------------------------===//
```
However in LLDB most of our source files have arbitrary changes to this format and
these changes are spreading through LLDB as folks usually just use the existing
source files as templates for their new files (most notably the unnecessary
editor language indicator `-*- C++ -*-` is spreading and in every review
someone is pointing out that this is wrong, resulting in people pointing out that this
is done in the same way in other files).

This patch removes most of these inconsistencies including the editor language indicators,
all the different missing/additional '-' characters, files that center the file name, missing
trailing `===//` (mostly caused by clang-format breaking the line).

Reviewers: aprantl, espindola, jfb, shafik, JDevlieghere

Reviewed By: JDevlieghere

Subscribers: dexonsmith, wuzish, emaste, sdardis, nemanjai, kbarton, MaskRay, atanasyan, arphaman, jfb, abidh, jsji, JDevlieghere, usaxena95, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D73258

Summary:
This change increases the offset of MPX registers (by 128) so they
do not overlap with the offset associated with AVX registers. That was
causing MPX data in GDBRemoteRegisterContext::m_reg_data to get overwritten.

Reviewers: labath

Reviewed By: labath

Subscribers: JDevlieghere, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D68874

Summary:
This patch follows the spirit of D63594, and removes some null checks
for things which should be operating invariants. Specifically
{Read,Write}[GF]PR now no longer check whether the supplied buffers are
null, because they never are. After this, the Do*** versions of these
function no longer serve any purpose and are inlined into their callers.

Other cleanups are possible here too, but I am taking this one step at a
time because this involves a lot of architecture-specific code, which I
don't have the hardware to test on (I did do a build-test though).

Reviewers: mgorny, jankratochvil, omjavaid, alexandreyy, uweigand

Subscribers: nemanjai, javed.absar, kbarton, lldb-commits

Differential Revision: https://reviews.llvm.org/D66744

llvm-svn: 370653