We must avoid emitting applies of `_diagnoseUnavailableCodeReached()` in
function bodies that are already marked unreachable since there isn't a valid
insertion point once an `unreachable` instruction has been emitted. A function
body may be marked unreachable if, for example, the parameters of the function
are uninhabited.
Resolves rdar://116246677
The closure with applied base is not escaping and gets applied
only once (when self is fully initialized). Let's make sure that
the partial application results in on-stack closure that borrows
"self" instead of copying it.
Lower the thrown error type into the SIL function type. This requires
very little code because the thrown error type was already modeled as
a SILResultInfo, which carries type information. Note that this
lowering does not yet account for error types that need to passed
indirectly, but we will need to do so for (e.g.) using resilient error
types.
Teach a few places in SIL generation not to assume that thrown types
are always the existential error type, which primarily comes down to
ensuring that rethrow epilogues have the thrown type of the
corresponding function or closure.
Teach throw emission to implicitly box concrete thrown errors in the
error existential when needed to satisfy the throw destination. This
is a temporary solution that helps translate typed throws into untyped
throws, but it should be replaced by a better modeling within the AST
of the points at which thrown errors are converted.
Add the thrown type into the AST representation of function types,
mapping from function type representations and declarations into the
appropriate thrown type. Add tests for serialization, printing, and
basic equivalence of function types that have thrown errors.
Parse typed throw specifiers as `throws(X)` in every place where there
are effects specified, and record the resulting thrown error type in
the AST except the type system. This includes:
* `FunctionTypeRepr`, for the parsed representation of types
* `AbstractFunctionDecl`, for various function-like declarations
* `ClosureExpr`, for closures
* `ArrowExpr`, for parsing of types within expression context
This also introduces some serialization logic for the thrown error
type of function-like declarations, along with an API to extract the
thrown interface type from one of those declarations, although right
now it will either be `Error` or empty.
Function bodies are skipped during typechecking when one of the
-experimental-skip-*-function-bodies flags is passed to the frontend. This was
implemented by setting the "body kind" of an `AbstractFunctionDecl` during decl
checking in `TypeCheckDeclPrimary`. This approach had a couple of issues:
- It is incompatible with skipping function bodies during lazy typechecking,
since the skipping is only evaluated during a phase of eager typechecking.
- It prevents skipped function bodies from being parsed on-demand ("skipped" is
a state that is distinct from "parsed", when they ought to be orthogonal).
This needlessly prevented complete module interfaces from being emitted with
-experimental-skip-all-function-bodies.
Storing the skipped status of a function separately from body kind and
requestifying the determination of whether to skip a function solves these
problems.
Resolves rdar://116020403
If we have an uninhabited branch, emit it as an
ignored expr followed by an unreachable.
Previously we would omit the unreachable and rely
on the SILOptimizer to infer it, but we ought to
just emit it here. Also check `isUninhabited()`
instead of `isStructurallyUninhabited` since this
better matches what we allow in Sema. For tuples
of uninhabited values, we can do a regular
initialization without issue.
I think from SIL's perspective, it should only worry about whether the
type is move-only. That includes MoveOnlyWrapped SILTypes and regular
types that cannot be copied.
Most of the code querying `SILType::isPureMoveOnly` is in SILGen, where
it's very likely that the original AST type is sitting around already.
In such cases, I think it's fine to ask the AST type if it is
noncopyable. The clarity of only asking the ASTType if it's noncopyable
is beneficial, I think.
KeyPath's getter/setter/hash/equals functions have their own calling
convention, which receives generic arguments and embedded indices from a
given KeyPath argument buffer.
The convention was previously implemented by:
1. Accepting an argument buffer as an UnsafeRawPointer and casting it to
indices tuple pointer in SIL.
2. Bind generic arguments info from the given argument buffer while emitting
prologue in IRGen by creating a new forwarding thunk.
This 2-phase lowering approach was not ideal, as it blocked KeyPath
projection optimization [^1], and also required having a target arch
specific signature lowering logic in SIL-level [^2].
This patch centralizes the KeyPath accessor calling convention logic to
IRGen, by introducing `@convention(keypath_accessor_XXX)` convention in
SIL and lowering it in IRGen. This change unblocks the KeyPath projection
optimization while capturing subscript indices, and also makes it easier
to support WebAssembly target.
[^1]: https://github.com/apple/swift/pull/28799
[^2]: https://forums.swift.org/t/wasm-support/16087/21
The problem was that in the by-address emission, we were calling
`getAddressForInPlaceInitialization` twice, triggering the assert.
The first time in `emitExprInto` for the normal result case.
The second time to obtain the address again when generating the
catch block to inject a `.none` into that same address.
This patch does a light refactoring to more closely mirror
`visitOptionalEvaluationExpr`, which avoids calling the asserting method.
fixes rdar://80277465
getClosureActorIsolation.
This is preparation for changing AbstractClosureExpr to store
ActorIsolation instead of ClosureActorIsolation, and convert to
ClosureActorIsolation when needed to allow incrementally updating
callers. This change is NFC.
The payload is stored maximally-abstracted, so make sure we respect
that to avoid a crash when the 'async let' binding has a function type.
Fixes rdar://114823719.
Because `CheckedContinuation` is not a @frozen struct we have
to use `Any` to store it in @block_storage indirectly. If the
flag is enabled, we'd emit a block storage with `Any` and
initialize the existential with stack allocated `CheckedContinuation`
formed from `UnsafeContinuation`. Inside of the completion handler
`Any` is going to be projected and cast back to `CheckedContinuation`.
These allow multi-statement `if`/`switch` expression
branches that can produce a value at the end by
saying `then <expr>`. This is gated behind
`-enable-experimental-feature ThenStatements`
pending evolution discussion.
