WASM currently is treated identically to the ELF paths. Collocate the
types to make it easier to ensure that all the paths are correctly
handling the emission. This adds the missed case for the module hash.
The `_Differentiation` module is the experimental support library for
differentiable programming. It is built when the build-script flag
`--enable-experimental-differentiable-programming` is enabled.
The `Differentiable` protocol generalizes all types that work with
differentiation. It is a core piece of the differentiable programming
project. Other parts depending on the `Differentiable` protocol will
be upstreamed piece by piece.
The `Differentiable` protocol is compiler-known and will be used during
type-checking, SILGen, and the SIL differentiation transform.
Structurally prevent a number of common anti-patterns involving generic
signatures by separating the interface into GenericSignature and the
implementation into GenericSignatureBase. In particular, this allows
the comparison operators to be deleted which forces callers to
canonicalize the signature or ask to compare pointers explicitly.
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!)
We were unnecessarily conservative here; generic metadata patterns support indirectable references
to value witness tables exported by the standard library, so if we have a fixed-layout generic
type that matches a known value witness table layout, use that instead of generating a new
value witness table.
When we generate code that asks for complete metadata for a fully concrete specific type that
doesn't have trivial metadata access, like `(Int, String)` or `[String: [Any]]`,
generate a cache variable that points to a mangled name, and use a common accessor function
that turns that cache variable into a pointer to the instantiated metadata. This saves a bunch
of code size, and should have minimal runtime impact, since the demangling of any string only
has to happen once.
This mostly just works, though it exposed a couple of issues:
- Mangling a type ref including objc protocols didn't cause the objc protocol record to get
instantiated. Fixed as part of this patch.
- The runtime type demangler doesn't correctly handle retroactive conformances. If there are
multiple retroactive conformances in a process at runtime, then even though the mangled string
refers to a specific conformance, the runtime still just picks one without listening to the
mangler. This is left to fix later, rdar://problem/53828345.
There is some more follow-up work that we can do to further improve the gains:
- We could improve the runtime-provided entry points, adding versions that don't require size
to be cached, and which can handle arbitrary metadata requests. This would allow for mangled
names to also be used for incomplete metadata accesses and improve code size of some generic
type accessors. However, we'd only be able to take advantage of the new entry points in
OSes that ship a new runtime.
- We could choose to always symbolic reference all type references, which would generally reduce
the size of mangled strings, as well as make runtime demangling more efficient, since it wouldn't
need to hit the runtime caches. This would however require that we be able to handle symbolic
references across files in the MetadataReader in order to avoid regressing remote mirror
functionality.
The code here was not correct in a situation where an opaque type had constraints that were
refinements of the protocol requirements of an associated type, as in:
```
protocol ParentProtocol {}
protocol SubProtocol: ParentProtocol {}
protocol P {
associatedtype A: ParentProtocol
func foo() -> A
}
struct S: P {
func foo() -> some SubProtocol
}
```
because it assumed that the conformance could be found directly on the opaque type instead of
potentially via an arbitrary MetadataPath. Falling through to the code that already correctly
handles archetype conformances right below the removed code does the right thing. Fixes
rdar://problem/53081207.
This improves on the previous situation:
- The request ensures that the backing storage for lazy properties
and property wrappers gets synthesized first; previously it was
only somewhat guaranteed by callers.
- Instead of returning a range this just returns an ArrayRef,
which simplifies clients.
- Indexing into the ArrayRef is O(1), which addresses some FIXMEs
in the SIL optimizer.
When referencing a superclass type from a subclass, for example, the
type uses the subclass's generic parameters, not the superclass's.
This can be important if a nested type constrains away some of its
parent type's generic parameters.
This doesn't solve all the problems around mis-referenced generic
parameters when some are constrained away, though. That might
require a runtime change. See the FIXME comments in the test cases.
rdar://problem/51627403
Add `llvm_unreachable` to mark covered switches which MSVC does not
analyze correctly and believes that there exists a path through the
function without a return value.
They aren't normally decl contexts, but if one has an opaque type, we want to be able to record
the property as a context so that we can reconstruct it in RemoteAST.
This is to support dynamic function replacement of functions with opaque
result type.
This approach requires that all state is thrown away (that could contain the
old returned type for an opaque type) between replacements.
rdar://48887938
Previously even if a type's metadata was optimized away, we would still
emit a field descriptor, which in turn could reference nominal type
descriptors for other types via symbolic references, etc.
Instead of a wholly separate lazyness mechanism for foreign metadata where
the first call to getAddrOfForeignTypeMetadataCandidate() would emit the
metadata, emit it using the lazy metadata mechanism.
This eliminates some code duplication. It also ensures that foreign
metadata is only emitted once per SIL module, and not once per LLVM
module, avoiding duplicate copies that must be ODR'd away in multi-threaded
mode.
This fixes the test case from <rdar://problem/49710077>.
Non-generic classes with resilient ancestry do not have statically-emitted
metadata, so we can now emit an Objective-C resilient class stub instead.
Also, when emitting an Objective-C category, reference the class stub if
the class has resilient ancestry; previously this case would hit an assert.
Note that class stubs always start with a zero word, with the address point
pointing immediately after. This works around a linker issue, where the
linker tries to coalesce categories and gets confused upon encountering a
class stub.
* Teach the importer to import any vector type as SIMDN<Scalar>.
Instead of having a known set of vector types, check to see if the
element type conforms to SIMDScalar; if it does, see if we have a
SIMDN defined with the right number of elements. If both are satisfied,
import the vector type as that Swift type.
By making this change, we gain the ability to import vector types
that aren't defined in terms of the Darwin simd module, which lets
us use C API with vector types on other platforms. It also lets us
import *every* vector type that Swift can represent, rather than the
small subset that are currently hardcoded.
* Increased test coverage for increased SIMD types that we can import.
Includes some minor cleanup from review. Also eliminates the old
simd_sans_simd test, since we can now import all of these types even when the simd module isn't imported.
