In this PR we teach `ClangImporter` to import typedef statements with template instantiation as its underlying type.
```c++
template<class T>
struct MagicWrapper {
T t;
};
struct MagicNumber {};
typedef MagicWrapper<MagicNumber> WrappedMagicNumber;
```
will be made available in Swift as if `WrappedMagicNumber` is a regular struct.
In C++, multiple distinct typedeffed instantiations resolve to the same canonical type. We implement this by creating a hidden intermediate struct that typedef aliasses.
The struct is named as `__CxxTemplateInst` plus Itanium mangled type of the instantiation. For the example above the name of the hidden struct is `__CxxTemplateInst12MagicWrapperI11MagicNumberE`. Double underscore (denoting a reserved C++ identifier) is used to discourage direct usage. We chose Itanium mangling scheme because it produces valid Swift identifiers and covers all C++ edge cases.
Imported module interface of the example above:
```swift
struct __CxxTemplateInst12MagicWrapperI11MagicNumberE {
var t: MagicNumber
}
struct MagicNumber {}
typealias WrappedMagicNumber = __CxxTemplateInst12MagicWrapperI11MagicNumberE
```
We modified the `SwiftLookupTable` logic to show hidden structs in `swift_ide_test` for convenience.
Resolves https://bugs.swift.org/browse/SR-12591.
Co-authored-by: Rosica Dejanovska <rosica@google.com>
Co-authored-by: Dmitri Gribenko <gribozavr@gmail.com>
Co-authored-by: Robert Widmann <devteam.codafi@gmail.com>
* [Mangling] Add a new mangling to represent opaque return type for ObjC runtime name
* [Docs] Add the new 'Qu' mangling to 'Mangling.rst' document
* [Test] Update test invocation arguments
Add `async` to the type system. `async` can be written as part of a
function type or function declaration, following the parameter list, e.g.,
func doSomeWork() async { ... }
`async` functions are distinct from non-`async` functions and there
are no conversions amongst them. At present, `async` functions do not
*do* anything, but this commit fully supports them as a distinct kind
of function throughout:
* Parsing of `async`
* AST representation of `async` in declarations and types
* Syntactic type representation of `async`
* (De-/re-)mangling of function types involving 'async'
* Runtime type representation and reconstruction of function types
involving `async`.
* Dynamic casting restrictions for `async` function types
* (De-)serialization of `async` function types
* Disabling overriding, witness matching, and conversions with
differing `async`
When a generic type from a different module is not resilient within the
current module and at least one of its arguments is from the current
module, emit a non-canonical prespecialized record, and access that
metadata via a call to swift_getCanonicalSpecializedMetadata, passing in
the non-canonical record.
rdar://problem/56996727
rdar://problem/56997022
`DifferentiableFunctionInst` now stores result indices.
`SILAutoDiffIndices` now stores result indices instead of a source index.
`@differentiable` SIL function types may now have multiple differentiability
result indices and `@noDerivative` resutls.
`@differentiable` AST function types do not have `@noDerivative` results (yet),
so this functionality is not exposed to users.
Resolves TF-689 and TF-1256.
Infrastructural support for TF-983: supporting differentiation of `apply`
instructions with multiple active semantic results.
Mangle `@noDerivative` parameters to fix type reconstruction errors.
Resolves SR-12650. The new mangling is non-breaking.
When differentiation supports multiple result indices and `@noDerivative`
results are added, we can reuse some of this mangling support.
Add mangling scheme for `@differentiable` and `@differentiable(linear)` function
types. Mangling support is important for debug information, among other things.
Update docs and add tests.
Resolves TF-948.
In order to allow this, I've had to rework the syntax of substituted function types; what was previously spelled `<T> in () -> T for <X>` is now spelled `@substituted <T> () -> T for <X>`. I think this is a nice improvement for readability, but it did require me to churn a lot of test cases.
Distinguishing the substitutions has two chief advantages over the existing representation. First, the semantics seem quite a bit clearer at use points; the `implicit` bit was very subtle and not always obvious how to use. More importantly, it allows the expression of generic function types that must satisfy a particular generic abstraction pattern, which was otherwise impossible to express.
As an example of the latter, consider the following protocol conformance:
```
protocol P { func foo() }
struct A<T> : P { func foo() {} }
```
The lowered signature of `P.foo` is `<Self: P> (@in_guaranteed Self) -> ()`. Without this change, the lowered signature of `A.foo`'s witness would be `<T> (@in_guaranteed A<T>) -> ()`, which does not preserve information about the conformance substitution in any useful way. With this change, the lowered signature of this witness could be `<T> @substituted <Self: P> (@in_guaranteed Self) -> () for <A<T>>`, which nicely preserves the exact substitutions which relate the witness to the requirement.
When we adopt this, it will both obviate the need for the special witness-table conformance field in SILFunctionType and make it far simpler for the SILOptimizer to devirtualize witness methods. This patch does not actually take that step, however; it merely makes it possible to do so.
As another piece of unfinished business, while `SILFunctionType::substGenericArgs()` conceptually ought to simply set the given substitutions as the invocation substitutions, that would disturb a number of places that expect that method to produce an unsubstituted type. This patch only set invocation arguments when the generic type is a substituted type, which we currently never produce in type-lowering.
My plan is to start by producing substituted function types for accessors. Accessors are an important case because the coroutine continuation function is essentially an implicit component of the function type which the current substitution rules simply erase the intended abstraction of. They're also used in narrower ways that should exercise less of the optimizer.
This removes it from the AST and largely replaces it with AnyObject
at the SIL and IRGen layers. Some notes:
- Reflection still uses the notion of "unknown object" to mean an
object with unknown refcounting. There's no real reason to make
this different from AnyObject (an existential containing a
single object with unknown refcounting), but this way nothing
changes for clients of Reflection, and it's consistent with how
native objects are represented.
- The value witness table and reflection descriptor for AnyObject
use the mangling "BO" instead of "yXl".
- The demangler and remangler continue to support "BO" because it's
still in use as a type encoding, even if it's not an AST-level
Type anymore.
- Type-based alias analysis for Builtin.UnknownObject was incorrect,
so it's a good thing we weren't using it.
- Same with enum layout. (This one assumed UnknownObject never
referred to an Objective-C tagged pointer. That certainly wasn't how
we were using it!)
Teach SILGen to emit a separate SIL function to capture the
initialization of the backing storage type for a wrapped property
based on the wrapped value. This eliminates manual code expansion at
every use site.
The archetype mangling does not have enough information to accurately recover the associated type
at runtime. This fixes rdar://problem/54084733.
Although this changes the mangling in both runtime and symbols, this should not affect ABI, because
there is no way for associated types of opaque types to be surfaced in the types of public
declarations today.
When mangling a dependent protocol conformance ref, the mangler currently uses `0_` to mean an unknown index and `N_` to mean the index `N - 1`. Unfortunately, this is somewhat confused: `0_` is actually the mangling for index 1, and index 0 is supposed to be mangled as just `_`, so true indexes are actually offset by 2. So the first thing to do here is to clarify what's going on throughout the mangler, demangler, and ABI documentation.
Also, the demangler attempts to produce a `DependentProtocolConformance*` node with the appropriate child nodes and an optional index payload. Unfortunately, demangle nodes cannot have both children and a value payload, so whenever it creates a node with an index payload, the demangler will assert. It does this whenever the mangled index is not 0; since (per above) the mangler always produces a non-zero mangled index in this production, the demangler will always assert when processing these. So clearly this is well-tested code, since +asserts builds will always trigger the demangler when mangling a name in the first place. To fix this, we need to make the index a child of the mangling node instead of its payload; at the same time, we can make it store the semantically correct index value and just introduce a new `UnknownIndex` node to handle the `0_` case. This is easy because all current clients ignore this information.
Finally, due to an apparent copy-and-paste error, the demangler attempts to produce a `DependentProtocolConformanceRoot` node for associated protocol conformances; this is easily resolved.
This fixes the crash in SR-10926 (rdar://51710424). The obscurity of this crash --- which originally made us think it might be related to Error self-conformance --- is because it is only triggered when a function signature takes advantage of a concrete-but-dependent retroactive conformance, which (to be both concrete and dependent) must furthermore be conditional. Testing the other cases besides a root conformance requires an even more obscure testcase.
Our mangling did not encode if an Objective-C block was escaping or
not. This is not a huge problem in practice, but for debug info we
want type reconstruction to round-trip exactly. There was a previous
workaround to paper over this specific problem.
Remove the workaround, and add a new 'XL' mangling for escaping
blocks. Since we don't actually want to break ABI compatibility,
only use the new mangling in DWARF debug info.
Fixes a crash in IRGen
TODO: also fix the demangler/remangler part of this mangling change.
Currently it's not a problem because we never demangle such a symbol (it's even not round-trip checked in Mangler::verify).
rdar://problem/50405691
New(er) grammar:
// same module as conforming type, or non-unique
protocol-conformance-ref ::= protocol 'HP'
// same module as protocol
protocol-conformance-ref ::= protocol 'Hp'
// retroactive
protocol-conformance-ref ::= protocol module
We don't make use of this distinction anywhere yet, but we could in
the future.
Fix to 510b64fcd5. The mangling operator "HP" has to distinguish
between "protocol" and "protocol module", not between the presence
or absence of protocol-conformance-ref. New grammar:
protocol-conformance-ref ::= protocol
protocol-conformance-ref ::= protocol module 'HP'
rdar://problem/46735592, again
Due to some unfortunate refactoring, protocol-conformance-ref is a
nonterminal in the mangling grammar that doesn't have its own
operator:
```
protocol-conformance-ref ::= protocol module?
```
Both "module" and "protocol" can be an "identifier", which introduces
a mangling collision. Address the mangling collision by using the
operator "HP".
Fixes rdar://problem/46735592.
Start emitting associated conformance requirement descriptors for
inherited protocols, so we have a symbol to reference from resilient
witness tables and mangled names in the future.
Use a general ‘type’ production for the conforming type of an associated
witness table accessor mangling, so that we can mangle base protocol
witness table accessors. These entities are always internal symbols, so the
mangling itself doesn’t affect the ABI.
Always use mangled type names to represent type metadata in keypath patterns.
For generic types, use the generic environment to pull substituted types
from the instantiation arguments.
Finishes the type metadata part of rdar://problem/38038799.
