ImportDecl has an alternate decl quasi-escape-hatch where it can
create alternative declarations for the same original Clang node. But,
it was limited at one, which worked accidentally in the case of
VisitObjCMethodDecl's attempts at importing a factory-init-suppressed
root-class method that points to the imported-as-init Swift
declaration.
This commit changes that to a TinyPtrVector, to support the upcoming
occasional case where we have more.
A pointless use of polymorphism -- the result values are not
interchangeable in any practical sense:
- For GenericTypeParamDecls, this returned getDeclaredInterfaceType(),
which is an interface type.
- For AssociatedTypeDecls, this returned the sugared AssociatedTypeType,
which desugars to an archetype.
- For TypeAliasDecls, this returned TypeAliasDecl::getAliasType(),
which desugars to a type containing archetypes.
- For NominalTypeDecls, this returned NominalTypeDecl::getDeclaredType(),
which is the unbound generic type, a special case used for inferring
generic arguments when they're not written in source.
Previously, getInterfaceType() would return getType() if no
interface type was set. Instead, always set an interface type
explicitly.
Eventually we want to remove getType() altogether, and this
brings us one step closer to this goal.
Note that ParamDecls are excempt from this treatment, because
they don't have a proper interface type yet. Cleaning this up
requires more effort.
Previously, getInterfaceType() would return getType() if no
interface type was set. Instead, always set an interface type
explicitly.
Eventually we want to remove getType() altogether, and this
brings us one step closer to this goal.
Note that ParamDecls are excempt from this treatment, because
they don't have a proper interface type yet. Cleaning this up
requires more effort.
Swift side of this new flag. This allows Objective-C framework authors
to replace a pair of methods by properties without breaking source
compatibility. This is especially important for class properties,
which were only introduced last year.
Still to come: importing the accessors even when this flag isn't set,
in order to provide better QoI when migrating from a method interface
to a property interface.
Part of rdar://problem/28455962
An environment is always associated with a location with a signature, so
having them separate is pointless duplication. This patch also updates
the serialization to round-trip the signature data.
Reimplement the witness matching logic used for generic requirements
so that it properly models the expectations required of the witness,
then captures the results in the AST. The new approach has a number of
advantages over the existing hacks:
* The constraint solver no longer requires hacks to try to tangle
together the innermost archetypes from the requirement with the
outer archetypes of the context of the protocol
conformance. Instead, we create a synthetic set of archetypes that
describes the requirement as it should be matched against
witnesses. This eliminates the infamous 'SelfTypeVar' hack.
* The type checker no longer records substitutions involving a weird
mix of archetypes from different contexts (see above), so it's
actually plausible to reason about the substitutions of a witness. A
new `Witness` class contains the declaration, substitutions, and all
other information required to interpret the witness.
* SILGen now uses the substitution information for witnesses when
building witness thunks, rather than computing all of it from
scratch. ``substSelfTypeIntoProtocolRequirementType()` is now gone
(absorbed into the type checker, and improved from there), and the
witness-thunk emission code is simpler. A few other bits of SILGen
got simpler because the substitutions can now be trusted.
* Witness matching and thunk generation involving generic requirements
and nested generics now works, based on some work @slavapestov was
already doing in this area.
* The AST verifier can now verify the archetypes that occur in witness substitutions.
* Although it's not in this commit, the `Witness` structure is
suitable for complete (de-)serialization, unlike the weird mix of
archetypes previously present.
Fixes rdar://problem/24079818 and cleans up an area that's been messy
and poorly understood for a very, very long time.
Sugared GenericTypeParamTypes point to GenericTypeParamDecls,
allowing the name of the parameter as written by the user to be
recovered. Canonical GenericTypeParamTypes on the other hand
only store a depth and index, without referencing the original
declaration.
When printing SIL, we wish to output the original generic parameter
names, even though SIL only uses canonical types. Previously,
we used to accomplish this by mapping the generic parameter to an
archetype and printing the name of the archetype. This was not
adequate if multiple generic parameters mapped to the same
archetype, or if a generic parameter was mapped to a concrete type.
The new approach preserves the original sugared types in the
GenericEnvironment, adding a new GenericEnvironment::getSugaredType()
method.
There are also some other assorted simplifications made possible
by this.
Unfortunately this makes GenericEnvironments use a bit more memory,
however I have more improvements coming that will offset the gains,
in addition to making substitution lists smaller also.
UnconditionalAvailabilityKind => PlatformAgnosticAvailabilityKind
::UnavailableInCurrentSwift => ::SwiftVersionSpecific
Plus a couple related method renamings. Prep work for SR-2709.
Banish the abomination that is clangSemaOverride, a previously
necessary evil. When building the module caches, different Clang
instances will be spawned than the one used by the normal
importer. Since we want to reuse code and get the same name both ways,
this meant threading through alternative clang Semas and preprocessors
throughtout, some of the time. This broke the abstraction and
encapsulation of the Impl, complicated the programming model, and
otherwise made effective caching hard.
Now that we’ve done enough ImportName refactoring, we can create a
NameImporter per Clang instance, and encapsulate naming therein. We
can now remove the sema overrides, as we have already done to the
preprocessor overrides.
This shifts the 2-phase initialization problem to the Impl and the
Clang module writers.
NFC
SwiftNameLookupExtension and ClangImporter::Implementation were
friends, but as time goes on they have drifted apart. As part of the
ImportName refactoring, these are being decoupled to facilitate
multiple-name importing, and fight the existing false encapsulation
present in the Impl.
SwiftNameLookupExtension is now spun off into its own entity, and can
evolve to have and use its own de-coupled NameImporter.
There's a bit of a hack to deal with generic typealiases, but
overall this makes things more logical.
This is the last big refactoring before we can allow constrained
extensions to make generic parameters concrete. All that remains
is a small set of changes to SIL type lowering, and retooling
some diagnostics in Sema.
By refactoring out PlatformAvailability from the ClangImporter, we can
more easily refactor out isUnavailableInSwift from the impl, which
will free us up to do more flexible import naming.
Introduces new files ClangAdapter.h/cpp, which will serve as a
convenient place to put code reasoning about Clang details. Refactors
out most Clang-related is*, has*, and get* methods from the
ImporterImpl. In the future, an adapter class could help serve to
seperate the concerns of the importer from the details of how to
correctly use Clang APIs.
Refactor some 3k lines of code from the class definition (nested 3
indentation levels) to static functions or out-of-line
definitions. Reduces some of code browsing burden of the class, though
I hope to do more cleanup to the file as a whole.
NFC
Refactors out some definitions and types from the
ClangImporter::Implementation into a new component ImportName. Future
work will include more separation and finally some redesigning of name
determination components.
Now that SILFunctions no longer reference a GenericParamList, we
don't need to de-serialize cross-module references to archetypes
anymore.
This was the last remaining usage of AllArchetypes, so we can
finally rip it out.
A GenericEnvironment stores the mapping between GenericTypeParamTypes
and context archetypes (or eventually, concrete types, once we allow
extensions to constrain a generic parameter to a concrete type).
The goals here are two-fold:
- Eliminate the GenericTypeParamDecl::getArchetype() method, and
always use mapTypeIntoContext() instead
- Replace SILFunction::ContextGenericParams with a GenericEnvironment
This patch adds the new data type as well as serializer and AST
verifier support. but nothing else uses it yet.
Note that GenericSignature::get() now asserts if there are no
generic parameters, instead of returning null. This requires a
few tweaks here and there.
Simplify e.g., ASTContext::getBridgedToObjC(), which no longer needs
the optional return.
Eliminate the now-unused constraint kind for checking bridging to
Objective-C.
Like NSObject, CFType has primitive operations CFEqual and CFHash,
so Swift should allow those types to show up in Hashable positions
(like dictionaries). The most general way to do this was to
introduce a new protocol, _CFObject, and then have the importer
automatically make all CF types conform to it.
This did require one additional change: the == implementation that
calls through to CFEqual is in a new CoreFoundation overlay, but the
conformance is in the underlying Clang module. Therefore, operator
lookup for conformances has been changed to look in the overlay for
an imported declaration (if there is one).
https://bugs.swift.org/browse/SR-2388
