With '-sdk-module-cache-path', Swift textual interfaces found in the SDK will be built into a separate SDK-specific module cache.
Clang modules are not yet affected by this change, pending addition of the required API.
Teach scanner to pick and choose binary modules correctly based on if it
is testable import or not. Some situations that scanner need to be
careful when testable is involved:
* When it is a regular import, it should not import binary modules that
are built with -enable-testing, it should prefer interfaces if that is
available.
* When testable import, it should only load binary module and it should
make sure the internal imports from binary modules are actually
required for testable import to work.
If a testable import only find a regular binary module, dependency
scanner currently will just preceed with such module and leave the
diagnostics to swift-frontend, because the alternative (failed to find
module) can be confusing to users.
rdar://125914165
Add support for cross import modules by ingesting swiftoverlay files for
the cross import into CAS file system.
The long-term better fix will be just passing the cross import
information from scanner to swift-frontend so frontend doesn't need to
read overlay files again to figure out the cross import module.
rdar://123839248
Always prefer binary module when using @testable imports because the
swiftmodule rebuilt from interface cannot be imported as testable.
rdar://123120159
'ModuleDependencyScanner' maintains a Thread Pool along with a pool of workers
which are capable of executing a filesystem lookup of a named module dependency.
When resolving imports of a given Swift module, each import's resolution
operation can be issued asunchronously.
