This patch replaces (llvm::|)Optional< with std::optional<.  I'll post
a separate patch to clean up the "using" declarations, #include
"llvm/ADT/Optional.h", etc.

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

This patch adds #include <optional> to those files containing
llvm::Optional<...> or Optional<...>.

I'll post a separate patch to actually replace llvm::Optional with
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

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

Fix incorrect null-check logic, likely cause by copy-paste

Differential Revision: https://reviews.llvm.org/D130937

NativeProcessLinux is not able to properly read libraries-svr4 data when
running with ld.so as the "main" executable. Normally, this is not a big
problem, as it returns an error message, and lldb can fallback to manual
library loading.

Unfortunately, lldb-server also does not clear cached svr4 data on exec,
which means that it does *not* return an error when the application
execs from the "regular" to the "ld.so" mode. Instead it returns
incorrect data (it is missing the main executable) and causes
TestDyldExecLinux to fail (but only when building with xml support
enabled).

This patch makes ensures that cached process data is cleared on exec,
fixing the test. Since TestDyldExecLinux has shown to be sensitive to
the way we read library info, I fork it into two (with svr4 enabled and
disabled).

NativeProcessELF::GetELFImageInfoAddress<...>() is declared in NativeProcessELF.h, but only defined in NativeProcessELF.cpp. Via some optimized builds (e.g. thinlto), this instantiation may be removed when it is used in a different TU (NativeProcessELFTest.cpp).

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

Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.

Differential revision: https://reviews.llvm.org/D66259

llvm-svn: 368933