without relying on spare bit information in the reflection metadata
(which was added in #40906). As a result, we can remove the
code from #40906.
This is the first step in such removal. It removes the RemoteMirror
code for looking up such metadata. It leaves behind:
* Sufficient stubs for LLDB to continue to build. Once LLDB is updated, these stubs can be removed as well.
* The compiler code to emit such metadata. This allows new binaries to still reflect MPEs on older runtimes. This will need to be kept for a transitional period.
This patch fixes the location of the llvm remote inspection headers for
MSVC header lookup. MSVC appears to search in the directory of the
current header before returning to the specified header search
directories. When building SwiftRemoteMirror, the file contains a
reference to `swift/RemoteInspection/ReflectionContext.h`. Under
RelfectionContext.h, there is an include of "llvm/BinaryFormat/COFF.h".
Because there is an `llvm` and `llvm-c` directory inside of
`swift/RemoteInspection/`, and `ReflectionContext.h` is in that
directory, MSVC is expanding the `COFF.h` inside of the
RemoteInspection headers instead of the copy in LLVM itself, resulting
in eventually finding usages of `countPopulation` instead of using the
new `llvm::popcount` API, ultimately resulting in a build failure.
The fix is to ensure that the `llvm` header directory does not live
immediately next to the headers in RemoteInspection, but instead offset
them by one. The LLVM headers copied into RemoteInspection are supposed
to be used when compiling the runtime libraries, so I chose the name
"RuntimeHeaders".
