To support detecting MD5 checksum mismatches, deal with SupportFiles
rather than a plain FileSpecs in the SourceManager.

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.

These appear to be unused.

This patch changes the interface of
StructuredData::Array::GetItemAtIndexAsString to return a
`std::optional<llvm::StringRef>` instead of taking an out parameter.
More generally, this commit serves as proposal that we change all of the
sibling APIs (`GetItemAtIndexAs`) to do the same thing. The reason this
isn't one giant patch is because it is rather unwieldy changing just one
of these, so if this is approved, I will do all of the other ones as
individual follow-ups.

BreakpointResolver::CreateFromStructuredData returns a
BreakpointResolverSP, but all of the subclasses return raw pointers.
Instead of creating a raw pointer and shoving it into a shared pointer,
it seems reasonable to just create the shared pointer directly.

This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated.  The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

Identified by bugprone-argument-comment.

This patch refactors a good part of the code base turning the usual
FileSpec, Line, Column, CheckInlines, ExactMatch arguments into a
SourceLocationSpec object.

This change is required for a following patch that will add handling of the
column line information when doing symbol resolution.

Differential Revision: https://reviews.llvm.org/D100965

Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>

This prevents calling Breakpoint::shared_from_this of an object that is not owned by any shared_ptr.

Differential Revision: https://reviews.llvm.org/D74557

This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.

This doesn't actually modify StringRef yet, I'll do that in a follow-up.