SILGenBorrowedBaseVisitor did not take subscripts into account during its
visit. Add this case following the handling of MemberRefExpr for properties.
Fixes rdar://163022690.
Introduce copy_value + mark_unresolved_non_copyable_value + begin_borrow at the return value of
borrow accessor apply to drive move-only diagnostics.
Also strip the copy_value + mark_unresolved_non_copyable_value + begin_borrow trio in a few places, since
they create an artificial scope out of which we cannot return values in a borrow accessor
without resorting to unsafe SIL operations currently.
Borrow accessor diagnostics allow stripping these instructions safely in the following places:
- return value of a borrow accessor
- self argument reference in the borrow accessor return expression and borrow accessor apply
This is a new case that comes up with `InlineArray`, since an `InlineArray`
with unknown count but known trivial element type is trivial but still
address-only due to its unknown size. We are inconsistent about whether
we emit formal copies or not of these values; they should generally
be unnecessary as long as the memory location of a value is sufficiently
long-lived, but the SIL verifier still reasonably considers a `[take]` as
an invalidation of the memory, even though at runtime a take is a no-op.
Since the take is unnecessary, we can just not take when we copy out of
a trivial address location. Fixes#84141 | rdar://160007939.
If a subscript uses a read accessor to yield a noncopyable value,
we'd emit an `end_apply` that's too tightly scoped to allow for
a subsequent borrowing access on the yielded value.
resolves rdar://159079818
functions to compute them directly without a TypeLowering object, and
change a lot of getTypeLowering call sites to just use that.
There is one subtle change here that I think is okay: SILBuilder used to
use different TypeExpansionContexts when inserting into a global:
- getTypeLowering() always used a minimal context when inserting into
a global
- getTypeExpansionContext() always returned a maximal context for the
module scope
The latter seems more correct, as AFAIK global initializers are never
inlinable. If they are, we probably need to configure the builder with
an actual context properly rather than making global assumptions.
This is incremental progress towards computing this for most types
without a TypeLowering, and hopefully eventually removing TL entirely.
If a function is being semantically treated as having different concurrency
annotations because of a `@preconcurrency` import or language mode setting,
then SILGen may try to store an argument or result for a call using a value
that differs only in concurrency annotations, which can be safely bitcast
away.
Fixes rdar://154520999
When accessing stored properties out of an addressable variable or parameter
binding, the stored property's address inside the addressable storage of the
aggregate is itself addressable. Also, if a computed property is implemented
using an addressor, treat that as a sign that the returned address should be
used as addressable storage as well. rdar://152280207
Don't bind references to storage to use (new ABI) coroutine accessors
unless they're guaranteed to be available. For example, when building
against a resilient module that has coroutine accessors, they can only
be used if the deployment target is >= the version of Swift that
includes the feature.
rdar://148783895
Now that coroutine kind (and consequently ABI) for the accessors is
keyed off a SIL option, it's no longer possible to read whether a given
SILFunction arose from a read/modify coroutine just by checking its
coroutine kind. Regardless of ABI, read/modify coroutines may only
unwind (i.e. are only permitted not to "run to completion") if the
relevant experimental (soon to be deleted) feature is enabled.
The move-only checker relies on access markers to understand access scopes, so eliding them
entirely leads to miscompiles. We can emit `begin_access [unsafe]` to semantically delimit
exclusivity scopes while still doing no runtime checking. Fixes rdar://147546262.
PR #79084 adjusted the projection logic for addressor accessors to avoid
a temporary materialization in cases where the base value is already in
memory; however, many LValue physical components were still unconditionally
using `ManagedValue::forLValue` and causing unnecessary materializations
from already-read-accessed memory locations. Fixes rdar://147705667.
To ensure that dependent values have a persistent-enough memory representation
to point into, when an immutable binding is referenced as an addressable
argument to a call, have SILGen retroactively emit a stack allocation and
materialization that covers the binding's scope.
To ensure that dependent values have a persistent-enough memory representation
to point into, when an immutable binding is referenced as an addressable
argument to a call, have SILGen retroactively emit a stack allocation and
materialization that covers the binding's scope.
A read access asserts that the memory location is immutable for the duration
of the access, so it can be treated as a borrow rather than a mutable lvalue.
Doing this allows the borrow formal access scope fixes from #79084 to apply
to situations where a loadable type undergoes an accessor-based access with
indirect arguments (such as for public accessors when library evolution is
enabled for the type). Fixes rdar://143334632.
The return pointer may point into the materialized base value, so if the base needs
materialization, ensure that materialization covers any futher projection of the
value.
Previously, we would emit this as
%1 = load [copy] %address
%2 = moveonly_wrapper_to_copyable [owned] %1
which is difficult for move-only checking to handle, since %2 looks like a
consume of %1, making it difficult to determine %1's true lifetime. Change
this to
%1 = moveonly_wrapper_to_copyable_addr %address
%2 = load [copy] %address
which is handled better by move-only checking, improving the accuracy of
existing move-checking as well as fixing a spurious diagnostic when
indirect parameters get passed as by-value arguments to other functions.
When a protocol which has a read (or modify) requirement is built with
the CoroutineAccessors feature, it gains a read2 (or modify2,
respectively) requirement. For this to be compatible with binaries
built without the feature, a default implementation for these new
requirements must be provided. Cause these new accessor requirements to
have default implementations by returning `true` from
`doesAccessorHaveBody` when the context is a `ProtocolDecl` and the
relevant availability check passes.
