Add the machinery to support suppression of inference of conformance to
protocols that would otherwise be derived automatically.
This commit does not enable any conformances to be suppressed.
This change introduces a new compilation target platform to the Swift compiler - visionOS.
- Changes to the compiler build infrastrucuture to support building compiler-adjacent artifacts and test suites for the new target.
- Addition of the new platform kind definition.
- Support for the new platform in language constructs such as compile-time availability annotations or runtime OS version queries.
- Utilities to read out Darwin platform SDK info containing platform mapping data.
- Utilities to support re-mapping availability annotations from iOS to visionOS (e.g. 'updateIntroducedPlatformForFallback', 'updateDeprecatedPlatformForFallback', 'updateObsoletedPlatformForFallback').
- Additional tests exercising platform-specific availability handling and availability re-mapping fallback code-path.
- Changes to existing test suite to accomodate the new platform.
The check for actor methods in `isSemanticallyFinal` was accidentally
kicking in for class members, which avoided `Sendable` checking on
classes nested in actors.
This occurs when working with ActorIsolation in SIL.
This lets us avoid needing to depend on the AST for getting ActorIsolation for
self parameters. Now, we can just create the actor isolation we need based off
of the decl that we have.
The code is based off of forActorInstanceSelf(ValueDecl *decl) along the path
where it just creates isolation based off of the decl's nominal type decl (which
is equivalent to what we are trying to do here).
Introduce a predicate that determines when a given extension corresponds
to what one would get by existing the nominal type without spelling out
any constraints. This differs from the notion of a "constrained
extension" when the nominal type suppresses conformances on any of its
generic parameters, e.g.,
struct X<T: ~Copyable> { ... }
// doesn't spell out any constraints, but is constrained because it
// implicitly adds T: ~Copyable.
extension X { ... }
// does spell out constraints, but is not constrained because the
// generic signature matches that of X.
extension X where T: ~Copyable { }
Use this predicate when demangling a name to metadata, because name
mangling for extensions suppresses the generic signature for cases
where one "doesn't spell out any constraints."
Introduce metadata and runtime support for describing conformances to
"suppressible" protocols such as `Copyable`. The metadata changes occur
in several different places:
* Context descriptors gain a flag bit to indicate when the type itself has
suppressed one or more suppressible protocols (e.g., it is `~Copyable`).
When the bit is set, the context will have a trailing
`SuppressibleProtocolSet`, a 16-bit bitfield that records one bit for
each suppressed protocol. Types with no suppressed conformances will
leave the bit unset (so the metadata is unchanged), and older runtimes
don't look at the bit, so they will ignore the extra data.
* Generic context descriptors gain a flag bit to indicate when the type
has conditional conformances to suppressible protocols. When set,
there will be trailing metadata containing another
`SuppressibleProtocolSet` (a subset of the one in the main context
descriptor) indicating which suppressible protocols have conditional
conformances, followed by the actual lists of generic requirements
for each of the conditional conformances. Again, if there are no
conditional conformances to suppressible protocols, the bit won't be
set. Old runtimes ignore the bit and any trailing metadata.
* Generic requirements get a new "kind", which provides an ignored
protocol set (another `SuppressibleProtocolSet`) stating which
suppressible protocols should *not* be checked for the subject type
of the generic requirement. For example, this encodes a requirement
like `T: ~Copyable`. These generic requirements can occur anywhere
that there is a generic requirement list, e.g., conditional
conformances and extended existentials. Older runtimes handle unknown
generic requirement kinds by stating that the requirement isn't
satisfied.
Extend the runtime to perform checking of the suppressible
conformances on generic arguments as part of checking generic
requirements. This checking follows the defaults of the language, which
is that every generic argument must conform to each of the suppressible
protocols unless there is an explicit generic requirement that states
which suppressible protocols to ignore. Thus, a generic parameter list
`<T, Y where T: ~Escapable>` will check that `T` is `Copyable` but
not that it is `Escapable`, and check that `U` is both `Copyable` and
`Escapable`. To implement this, we collect the ignored protocol sets
from these suppressed requirements while processing the generic
requirements, then check all of the generic arguments against any
conformances not suppressed.
Answering the actual question "does `X` conform to `Copyable`?" (for
any suppressible protocol) looks at the context descriptor metadata to
answer the question, e.g.,
1. If there is no "suppressed protocol set", then the type conforms.
This covers types that haven't suppressed any conformances, including
all types that predate noncopyable generics.
2. If the suppressed protocol set doesn't contain `Copyable`, then the
type conforms.
3. If the type is generic and has a conditional conformance to
`Copyable`, evaluate the generic requirements for that conditional
conformance to answer whether it conforms.
The procedure above handles the bits of a `SuppressibleProtocolSet`
opaquely, with no mapping down to specific protocols. Therefore, the
same implementation will work even with future suppressible protocols,
including back deployment.
The end result of this is that we can dynamically evaluate conditional
conformances to protocols that depend on conformances to suppressible
protocols.
Implements rdar://123466649.
LLVM is presumably moving towards `std::string_view` -
`StringRef::startswith` is deprecated on tip. `SmallString::startswith`
was just renamed there (maybe with some small deprecation inbetween, but
if so, we've missed it).
The `SmallString::startswith` references were moved to
`.str().starts_with()`, rather than adding the `starts_with` on
`stable/20230725` as we only had a few of them. Open to switching that
over if anyone feels strongly though.
we only check if the loaded module is built from a package interface. This is
not enough as a binary module could just contain exportable decls if built with
experimental-skip-non-exportable-decls, essentially resulting in content equivalent
to interface content. This might be made a default behavior so this PR requires
a module to opt in to allow non-resilient access by a participating client in the
same package.
Since it affects module format, SWIFTMODULE_VERSION_MINOR is updated.
rdar://123651270
