These value witness table entries will be conditionally available for types that support specialized union representation through extra inhabitants and/or spare bits and for union value witnesses:
- storeExtraInhabitant, to store an extra inhabitant representation;
- getExtraInhabitantIndex, to recognize an extra inhabitant representation;
- getUnionTag, to get a union's discriminator; and
- inplaceProjectUnionData, to extract the value in place from a union.
This just sets up the enumerators and related IR types and mangling; nothing emits these witnesses yet.
Swift SVN r7234
We need to handle three cases:
- If a protocol conformance has no associated types, or the associated type witnesses all have statically resolvable metadata, we can expose a *direct* witness table symbol.
- If a protocol conformance has associated types with runtime-instantiated metadata, we need to gate the witness table behind a *lazy* initializer function to fill in the metadata fields.
- If a protocol conformance has associated types where the type or one of its conformances are *dependent* on its parent's generic parameters, we need to instantiate multiple witness tables at runtime.
Swift SVN r6805
We haven't fully updated references to union cases, and enums still are not
their own thing yet, but "oneof" is gone. Long live "union"!
Swift SVN r6783
the debug info, to aid the debugger in figuring out the implementation
language of a given type in multi-language environments.
FYI, where applicable, we also emit the
DW_AT_APPLE_runtime_class(DW_AT_lang_Swift) attribute.
The demangler accepts type names with the "_Tt" prefix without the --type
switch.
Swift SVN r6714
