We used to give witness thunks public linkage if the
conforming type and the protocol are public.
This is completely unnecessary. If the conformance is
fragile, the thunk should be [shared] [serialized],
allowing the thunk to be serialized into callers after
devirtualization.
Otherwise for private protocols or resilient modules,
witness thunks can just always be private.
This should reduce the size of compiled binaries.
There are two other mildly interesting consequences:
1) In the bridged cast tests, we now inline the witness
thunks from the bridgeable conformances, which removes
one level of indirection.
2) This uncovered a flaw in our accessibility checking
model. Usually, we reject a witness that is less
visible than the protocol; however, we fail to
reject it in the case that it comes from an
extension.
This is because members of an extension can be
declared 'public' even if the extended type is not
public, and it appears that in this case the 'public'
keyword has no effect.
I would prefer it if a) 'public' generated a warning
here, and b) the conformance also generated a warning.
In Swift 4 mode, we could then make this kind of
sillyness into an error. But for now, live with the
broken behavior, and add a test to exercise it to ensure
we don't crash.
There are other places where this "allow public but
ignore it, kinda, except respect it in some places"
behavior causes problems. I don't know if it was intentional
or just emergent behavior from general messiness in Sema.
3) In the TBD code, there is one less 'failure' because now
that witness thunks are no longer public, TBDGen does not
need to reason about them (except for the case #2 above,
which will probably require a similar workaround in TBDGen
as what I put into SILGen).
Also, add a third [serializable] state for functions whose bodies we
*can* serialize, but only do so if they're referenced from another
serialized function.
This will be used for bodies synthesized for imported definitions,
such as init(rawValue:), etc, and various thunks, but for now this
change is NFC.
This change simplifies some code and incidentally fixes a curious
corner case. We allow dynamic overrides of non-dynamic methods,
but we did not account for the fact that the override could have
a different calling convention.
SubstitutionList is going to be a more compact representation of
a SubstitutionMap, suitable for inline allocation inside another
object.
For now, it's just a typedef for ArrayRef<Substitution>.
The typedef `swift::Module` was a temporary solution that allowed
`swift::Module` to be renamed to `swift::ModuleDecl` without requiring
every single callsite to be modified.
Modify all the callsites, and get rid of the typedef.
For this we need to store the linkage of the “original” method implementation in the vtable.
Otherwise DeadFunctionElimination thinks that the method implementation is not public but private (which is the linkage of the thunk).
The big part of this change is to extend SILVTable to store the linkage (+ serialization, printing, etc.).
fixes rdar://problem/29841635
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.
This patch is rather large, since it was hard to make this change
incrementally, but most of the changes are mechanical.
Now that we have a lighter-weight data structure in the AST for mapping
interface types to archetypes and vice versa, use that in SIL instead of
a GenericParamList.
This means that when serializing a SILFunction body, we no longer need to
serialize references to archetypes from other modules.
Several methods used for forming substitutions can now be moved from
GenericParamList to GenericEnvironment.
Also, GenericParamList::cloneWithOuterParameters() and
GenericParamList::getEmpty() can now go away, since they were only used
when SILGen-ing witness thunks.
Finally, when printing generic parameters with identical names, the
SIL printer used to number them from highest depth to lowest, by
walking generic parameter lists starting with the innermost one.
Now, ambiguous generic parameters are numbered from lowest depth
to highest, by walking the generic signature, which means test
output in one of the SILGen tests has changed.
This is still a pretty bad code-generation pattern, but the layering
stuff makes it challenging to do the right thing.
Also, bridge non-optional NSErrors to Error using init_existential_ref
instead of going through the runtime function.
rdar://27810321
Imported Cocoa error types are represented by structs wrapping an
NSError. The conversion from these structs to Error would end up
boxing the structs in _SwiftNativeNSError, losing identity and leading
to a wrapping loop.
Instead, extract the embedded NSError if there is one. In the Swift
runtime, do this as part of the dynamic cast to NSError, using a (new,
defaulted) requirement in the Error type so we can avoid an extra
runtime lookup of the protocol. In SILGEn, do this by looking for the
_BridgedStoredNSError protocol conformance when erasing to an Error
type. Fixes SR-1562 / rdar://problem/26370984.
Previously, if a generic type had a stored property with
a generic type and an initializer expression, we would
emit the expression directly in the body of each designated
initializer.
This is a problem if the designated initializer is defined
within an extension (even in the same source file), because
extensions have a different set of generic parameters and
archetypes.
Also, we've had bugs in the past where emitting an
expression multiple times didn't work properly. While these
might currently all be fixed, this is a tricky case to test
and it would be best to avoid it.
Fix both problems by emitting the initializer expression
inside its own function at the SIL level, and call the
initializer function from each designated initializer.
I'm using the existing 'variable initializer' mangling for this;
it doesn't seem to be used for anything else right now.
Currently, the default memberwise initializer does not use
this, because the machinery for emitting it is somewhat
duplicated and separate from the initializer expressions in
user-defined constructors. I'll clean this up in an upcoming
patch.
Fixes <https://bugs.swift.org/browse/SR-488>.
What I've implemented here deviates from the current proposal text
in the following ways:
- I had to introduce a FunctionArrowPrecedence to capture the parsing
of -> in expression contexts.
- I found it convenient to continue to model the assignment property
explicitly.
- The comparison and casting operators have historically been
non-associative; I have chosen to preserve that, since I don't
think this proposal intended to change it.
- This uses the precedence group names and higherThan/lowerThan
as agreed in discussion.
We did this for func decls in script, so that DI can flag func decls that access script globals before they've been initialized, but we failed to do so for closures, causing us to miss DI violations when closures referenced script globals before their initialization. Fixes rdar://problem/24357063.
This reverts commit 052d2d0a69.
The only actual issue with the original change was a missing change to
the UIApplicationMain SILGen test, which needs to build SILGen
overlays to execute properly; -enable-source-import doesn't suffice.
Introduce a new entrypoint to _ObjectiveCBridgeable,
_unconditionallyBridgeFromObjectiveC, which handles unconditional
bridging from an optional Objective-C object (e.g., an NSString) to
its bridged Swift type. Use it in SILGen to perform NSString -> String
bridging rather than the custom entry point.
Another small step toward generalized bridging.
Provide a general mechanism for bridging from a Swift value type to
its corresponding Objective-C class type through the
_bridgeToObjectiveC witness of the appropriate _ObjectiveCBridgeable
protocol conformance. Only enable this new code for bridging String ->
NSString and work through the issues that crop up.
We cannot actually *delete* the _convertStringtoNSString entrypoint
yet, because there is some code that is depending on it indirectly;
I'll address that separately as part of the continued generalization
of the _ObjectiveCBridgeable mechanism.
Fix some interface type/context type confusion in the AST synthesis from the previous patch, add a unique private mangling for behavior protocol conformances, and set up SILGen to emit the conformances when property declarations with behaviors are visited. Disable synthesis of the struct memberwise initializer if any instance properties use behaviors; codegen will need to be redesigned here.
This will be used to help IRGen record protocol requirements
with resilient default implementations in protocol metadata.
To enable testing before all the Sema support is in place, this
patch adds SIL parser, printer and verifier support for default
witness tables.
For now, SILGen emits empty default witness tables for protocol
declarations in resilient modules, and IRGen ignores them when
emitting protocol metadata.
The main idea here is that we really, really want to be
able to recover the protocol requirement of a conformance
reference even if it's abstract due to the conforming type
being abstract (e.g. an archetype). I've made the conversion
from ProtocolConformance* explicit to discourage casual
contamination of the Ref with a null value.
As part of this change, always make conformance arrays in
Substitutions fully parallel to the requirements, as opposed
to occasionally being empty when the conformances are abstract.
As another part of this, I've tried to proactively fix
prospective bugs with partially-concrete conformances, which I
believe can happen with concretely-bound archetypes.
In addition to just giving us stronger invariants, this is
progress towards the removal of the archetype from Substitution.
Parameters (to methods, initializers, accessors, subscripts, etc) have always been represented
as Pattern's (of a particular sort), stemming from an early design direction that was abandoned.
Being built on top of patterns leads to patterns being overly complicated (e.g. tuple patterns
have to have varargs and default parameters) and make working on parameter lists complicated
and error prone. This might have been ok in 2015, but there is no way we can live like this in
2016.
Instead of using Patterns, carve out a new ParameterList and Parameter type to represent all the
parameter specific stuff. This simplifies many things and allows a lot of simplifications.
Unfortunately, I wasn't able to do this very incrementally, so this is a huge patch. The good
news is that it erases a ton of code, and the technical debt that went with it. Ignoring test
suite changes, we have:
77 files changed, 2359 insertions(+), 3221 deletions(-)
This patch also makes a bunch of wierd things dead, but I'll sweep those out in follow-on
patches.
Fixes <rdar://problem/22846558> No code completions in Foo( when Foo has error type
Fixes <rdar://problem/24026538> Slight regression in generated header, which I filed to go with 3a23d75.
Fixes an overloading bug involving default arguments and curried functions (see the diff to
Constraints/diagnostics.swift, which we now correctly accept).
Fixes cases where problems with parameters would get emitted multiple times, e.g. in the
test/Parse/subscripting.swift testcase.
The source range for ParamDecl now includes its type, which permutes some of the IDE / SourceModel tests
(for the better, I think).
Eliminates the bogus "type annotation missing in pattern" error message when a type isn't
specified for a parameter (see test/decl/func/functions.swift).
This now consistently parenthesizes argument lists in function types, which leads to many diffs in the
SILGen tests among others.
This does break the "sibling indentation" test in SourceKit/CodeFormat/indent-sibling.swift, and
I haven't been able to figure it out. Given that this is experimental functionality anyway,
I'm just XFAILing the test for now. i'll look at it separately from this mongo diff.
Move these to SILDeclRef, maybe not the best place but a good home for now.
Factor out a new requiresForeignToNativeThunk() function, which cleans up
some code duplication introduced by the following patch:
478e1c7513
This is a small step towards consolidating duplicated logic for figuring out
method dispatch semantics and emitting curry thunks.
These are contexts where we have enough information to bridge /back/
properly; that is, where we can distinguish CBool, ObjCBool, and
DarwinBoolean. In cases where we can't, we keep the three separate;
only CBool is really the same type as Bool.
This also affects current import behavior for ObjCBool, which was previously
incorrectly conflated with CBool in certain cases.
More rdar://problem/19013551
Swift SVN r30051
The other part of rdar://problem/21444126. This is a little trickier since SIL doesn't track uses of witness tables in a principled way. Track uses in SILGen by putting a "SILGenBuilder" wrapper in front of SILBuilder, which marks conformances from apply, existential erasure, and metatype lookup instructions as used, so we can avoid emitting shared Clang importer witnesses when they aren't needed.
Swift SVN r29544
If a SILDeclRef references a decl that isn't explicit in the source code and can't be referenced externally, then we only need to emit it if it's referenced in the current TU. Partially addresses rdar://problem/21444126, though we still eagerly generate witness tables for generated conformances, which still pull in a bunch of noise.
Swift SVN r29536
This isn't as straightforward as it should be, since EnumElementDecls aren't AbstractFunctionDecls, but luckily there's only one trivial curry level with a thin metatype parameter.
Swift SVN r28991
Modules occupy a weird space in the AST now: they can be treated like
types (Swift.Int), which is captured by ModuleType. They can be
treated like values for disambiguation (Swift.print), which is
captured by ModuleExpr. And we jump through hoops in various places to
store "either a module or a decl".
Start cleaning this up by transforming Module into ModuleDecl, a
TypeDecl that's implicitly created to describe a module. Subsequent
changes will start folding away the special cases (ModuleExpr ->
DeclRefExpr, name lookup results stop having a separate Module case,
etc.).
Note that the Module -> ModuleDecl typedef is there to limit the
changes needed. Much of this patch is actually dealing with the fact
that Module used to have Ctx and Name public members that now need to
be accessed via getASTContext() and getName(), respectively.
Swift SVN r28284
