In order to perform layout, the remote mirrors library needs to know
about the size, alignment and extra inhabitants of builtin types.
Ideally we would emit a reflection info section in libswiftRuntime.o,
but in the meantime just duplicate builtin type metadata for all
builtin types referenced from the current module instead.
In practice only the stdlib and a handful of overlays like the SIMD
overlay use builtin types, and only a few at a time.
Tested manually by running swift-reflection-tool on the standard
library -- I'll add automated tests by using -parse-stdlib to
reference Builtin types in a subsequent patch that adds more layout
logic.
NFC if -enable-reflection-metadata is off.
We will be handing pointers to typerefs over the SwiftRemoteMirrors C
API boundary, at which point it is unclear who will hold onto a shared
pointer. The useful lifetime of a typeref is tied to the
ReflectionContext for which they were created anyway so, when it goes
away, all of those typerefs can go away anyway.
We can't use LLVM's bump-pointer allocator here because we only build
the Support library for the host. As a compromise, stuff new typeref
pointers into a vector pool, where they will be taken down during
ReflectionContext's destructor.
Although the SwiftRemoteMirror library targets a specific architecture,
it's still an external runtime, so treat it as such. The InProcess template
argument is reserved for truly in-process reflection in the Runtime.
