Switch one entry point in the runtime (swift_getExistentialTypeMetadata)
to use ProtocolDescriptorRef rather than a protocol descriptor. Update
IRGen to produce ProtocolDescriptorRef instances for its calls, setting
the discriminator bit appropriately.
Within the runtime, verify that all instances of ProtocolDescriptorRef have
the right layout, i.e., the discriminator bit is set for @objc protocols
but not Swift protocols.
Use ProtocolDescriptorRefs within the runtime representation of
existential type metadata (TargetExistentialTypeMetadata) instead of
bare protocol descriptor pointers. Start rolling out the use of
ProtocolDescriptorRef in a few places in the runtime that touch this
code. Note that we’re not yet establishing any strong invariants on
the TargetProtocolDescriptorRef instances.
While here, replace TargetExistentialTypeMetadata’s hand-rolled pointer
arithmetic with swift::ABI::TrailingObjects and centralize knowledge of
its layout better.
Since the mangling scheme and set of standard library types is effectively
fixed now, introduce known mangling substitutions for a number of new
standard library types, filling out the S[A-Za-z] space.
Reduces standard library binary size by ~195k.
And update the existential container's initializeWithTake implementation
in the runtime. After only allowing bitwise takable values in the
inline buffer we can use memcpy to move existential container values.
rdar://31414907
SR-343
Previously, swiftImageInspectionShared generated one specific library at
`lib/libswiftImageInspectionShared.a` for only the main arch and sdk.
Generic cross compilation and various changes to the build system to get
cross compilation to work will require swiftImageInspectionShared to
generate libraries at the proper subdirectory. Change the outputs to
agree with paths such as `lib/swift/linux/x86_64`
This is simpler, because the native form of that last argument is: a
pointer to a buffer (*) of pointers (*) to witness tables, which is
modelled as a buffer of void *s. Thus, void ***.
The count of the number of witness tables was designed to be an
assertion/check that we've hooked up all the infrastructure
correctly. Everything is now implemented, and the assertion has never
triggered, so it can be removed, saving some work.
Fixes rdar://problem/38038928.
Minimize the generic class metadata template by removing the
class header and base-class members. Add back the set of
information that's really required for instantiation.
Teach swift_allocateGenericClass how to allocate classes without
superclass metadata. Reorder generic initialization to establish
a stronger phase-ordering between allocation (the part that doesn't
really care about the generic arguments) and initialization (the
part that really does care about the generic arguments and therefore
might need to be delayed to handle metadata cycles).
A similar thing needs to happen for resilient class relocation.
The standard library stubs need to be built with swiftCore_EXPORTS
defined to ensure that the interfaces are exported as if the swiftCore
library was being built. This allows building the LongTests on Windows.
This is yet another waypoint on the path towards the final
generic-metadata design. The immediate goal is to make the
pattern a private implementation detail and to give the runtime
more visibility into the allocation and caching of generic types.
