This was an annoying change, but mostly mechanical. The goal here is
to create parallel structure between the two paths so that it isn't
utterly confusing to share common CRTP paths between them. The renaming
of translate->process is just to make sure that all of the call sites
get correctly rewritten.
I'm trying to create more parallel structure between the param
and result reabstraction code so that, hopefully, some of the
basic explosion reasoning can be shared.
Back in 33f4f57cc4 of
https://github.com/apple/swift/pull/28044 fame,
non-`CaptureKind::Constant:` uses of `Entry.val` in
`SILGenFunction::emitCaptures` were replaced with a use of the newly
added lambda `getAddressValue` applied at `Entry.val`.
The replacement of `Entry.value` with `getAddressValue(Entry.value)` in
the case of `CaptureKind::Box` had no effect.
Back then, the reason was that the condition
SGM.Types
.getTypeLowering(
valueType,
TypeExpansionContext::noOpaqueTypeArchetypesSubstitution(
expansion.getResilienceExpansion()))
.isAddressOnly() &&
!entryValue->getType().isAddress()
under which something other than the input was returned would never
hold: CaptureKind::Box is used for LValues and those never satisfy
`!entryValue->getType().isAddress()`.
Since that PR, the getAddressValue lambda has grown. There are two
additional aspects to consider: (1) forceCopy, (2) isPack. (1) is not
relevant because `false` was being passed for the `CaptureKind::Box`
case. (2) can not currently happen because pack lvalues haven't been
implemented. But even if they were implemented, the argument passed to
the lambda would still need to be an address.
The same all holds for the `CaptureKind::ImmutableBox` case which only
differs from the `CaptureKind::Box` by a couple of lines.
Way back in
commit d0bb0274e9
Author: Joe Groff <jgroff@apple.com>
Date: Mon Nov 23 11:47:09 2015 -0800
the convention was changed such that LValues were passed only by box
rather than by box and address. Delete the comment that says that both
are passed.
When storing an instance of some type that conforms to Hashable into an
lvalue of type AnyHashable, the source rvalue needs to be emitted within
a new SGFContext. Otherwise, the LocalVarInitialization for the var of
type AnyHashable would be used and an attempt would be made to store the
instance of the conforming type into the projected box.
In opaque values mode, emit the unowned copy instructions to convert as
follows:
strong_copy_unowned_value: `@owned $sil_unowned T` -> `@owned $T`
unowned_copy_value: `@owned T` -> `@owned $sil_unowned T`
Doing so is necessary in opaque values mode where it is needed to deal
with unowned values directly rather than indirectly via `load_unowned`s
and `store_unowned`s.
In opaque values mode, emit the new weak copy instructions to convert as
follows:
strong_copy_weak_value: `@owned $sil_weak T?` -> `@owned $T?`
weak_copy_value: `@owned $T?` -> `@owned $@sil_weak T?`
Doing so is necessary in opaque values mode where it is needed to deal
with weak values directly rather than indirectly via `load_weak`s and
`store_weak`s.
The new instruction wraps a value in a `@sil_weak` box and produces an
owned value. It is only legal in opaque values mode and is transformed
by `AddressLowering` to `store_weak`.
The new instruction unwraps an `@sil_weak` box and produces an owned
value. It is only legal in opaque values mode and is transformed by
`AddressLowering` to `load_weak`.
Introduce `AvailableDuringLoweringDeclFilter` which can be composed with
`OptionalTransformRange` to implement iterators that filter out unavailable
decls.
