The presence of Copyable/Escapable conformances doesn't affect ABI. Only
their absence in terms of suppressed requirements like `~Copyable` need
to be output for diffing by the APIDigester.
The error messages emitted from the ABI checker are mostly explanations of breakages. We should
explicitly mention why they are emitted to differentiate them from other compiler diagnostics.
rdar://68864860
The API digester tests were being run only for macOS, mainly
because they were not using %target-swift consistently. Lift
the unnecessary restriction so we run these tests more widely.
Using a directory instead of an exact file name for the generated
baseline allows the tool to use target triple as file name, which is
expected by the diagnostic phase.
We used to use a Json format to capture the ABI/API detail of Swift modules to
walk-around module compatibility issues across different compiler versions. Since
Swift module now is in stable format, we can compare two swiftinterface files
directly without dumping the content into Json format.
Protocol requirements may not necessarily add new entries to the witness table if
it's inherited from super protocol. This patch teaches the json dump to
include a flag indicating whether a protocol requirement requires new
witness table entry and diagnoses the change of such flag as ABI
breakages.
rdar://47657204
