The reason why I am doing this is that in certain cases the AST captures indices
will never actually line up with partial apply capture indices since we seem to
"smush" together closures and locally defined functions.
NOTE: The reason for the really small amount of test changes is that this change
does not change the actual output by design. The only cases I had to change were
a case where we began to emit a better diagnostic and also where I added code
coverage around _ and let _ since those require ignored_use to be implemented so
that they would be diagnosed (previously we just did not emit anything so we
couldn't emit the diagnostic at the SIL level).
rdar://142661388
This is used for synthetic uses like _ = x that do not act as a true use but
instead only suppress unused variable warnings. This patch just adds the
instruction.
Eventually, we can use it to move the unused variable warning from Sema to SIL
slimmming the type checker down a little bit... but for now I am using it so
that other diagnostic passes can have a SIL instruction (with SIL location) so
that we can emit diagnostics on code like _ = x. Today we just do not emit
anything at all for that case so a diagnostic SIL pass would not see any
instruction that it could emit a diagnostic upon. In the next patch of this
series, I am going to add SILGen support to do that.
I am adding this instruction to express artificially that two non-Sendable
values should be part of the same region. It is meant to be used in cases where
due to unsafe code using Sendable, we stop propagating a non-Sendable dependency
that needs to be made in the same region of a use of said Sendable value. I
included an example in ./docs/SIL.rst of where this comes up with @out results
of continuations.
In Embedded Swift, witness method lookup is done from specialized witness tables.
For this to work, the type of witness_method must be specialized as well.
Otherwise the method call would be done with wrong parameter conventions (indirect instead of direct).
For now this will only be used for HopToMainActorIfNeeded thunks. I am creating
this now since in the past there has only been one option for creating
thunks... to create the thunk in SILGen using SILGenThunk. This code is hard to
test and there is a lot of it. By using an instruction here we get a few benefits:
1. We decouple SILGen from needing to generate new kinds of thunks. This means
that SILGenThunk does not need to expand to handle more thunks.
2. All thunks implemented via ThunkInst will be easy to test in a decoupled way
with SIL tests.
3. Even though this stabilizes the patient, we still have many thunks in SILGen
and various parts of the compiler. Over time, we can swap to this model,
allowing us to hopefully eventually delete SILGenThunk.
Motivated by need for protocol-based dynamic dispatch, which hasn't been possible in Embedded Swift due to a full ban on existentials. This lifts that restriction but only for class-bound existentials: Class-bound existentials are already (even in desktop Swift) much more lightweight than full existentials, as they don't need type metadata, their containers are typically 2 words only (reference + wtable pointer), don't incur copies (only retains+releases).
Included in this PR:
[x] Non-generic class-bound existentials, executable tests for those.
[x] Extension methods on protocols and using those from a class-bound existential.
[x] RuntimeEffects now differentiate between Existential and ExistentialClassBound.
[x] PerformanceDiagnostics don't flag ExistentialClassBound in Embedded Swift.
[x] WTables are generated in IRGen when needed.
Left for follow-up PRs:
[ ] Generic classes support
Some requirement machine work
Rename requirement to Value
Rename more things to Value
Fix integer checking for requirement
some docs and parser changes
Minor fixes
Although I don't plan to bring over new assertions wholesale
into the current qualification branch, it's entirely possible
that various minor changes in main will use the new assertions;
having this basic support in the release branch will simplify that.
(This is why I'm adding the includes as a separate pass from
rewriting the individual assertions)
It indicates that the value's lifetime continues to at least this point.
The boundary formed by all consuming uses together with these
instructions will encompass all uses of the value.
An initializing store is not a copy and therefore doesn't perform ref counting operations
Fixes a false performance error when using non-copyable types.
https://github.com/apple/swift/issues/73582
LLVM is presumably moving towards `std::string_view` -
`StringRef::startswith` is deprecated on tip. `SmallString::startswith`
was just renamed there (maybe with some small deprecation inbetween, but
if so, we've missed it).
The `SmallString::startswith` references were moved to
`.str().starts_with()`, rather than adding the `starts_with` on
`stable/20230725` as we only had a few of them. Open to switching that
over if anyone feels strongly though.
Not de-virtualized value type deinits can require metatype in case the deinit needs to be called via the value witness table.
Usually this does not happen because deinits are mandatory de-virtualized. But it can show up if e.g. wrong build options are used.
rdar://122651706
* `alloc_vector`: allocates an uninitialized vector of elements on the stack or in a statically initialized global
* `vector`: creates an initialized vector in a statically initialized global
I also included changes to the rest of the SIL optimizer pipeline to ensure that
the part of the optimizer pipeline before we lower tuple_addr_constructor (which
is right after we run TransferNonSendable) work as before.
The reason why I am doing this is that this ensures that diagnostic passes can
tell the difference in between:
```
x = (a, b, c)
```
and
```
x.0 = a
x.1 = b
x.2 = c
```
This is important for things like TransferNonSendable where assigning over the
entire tuple element is treated differently from if one were to initialize it in
pieces using projections.
rdar://117880194
This commit just introduces the instruction. In a subsequent commit, I am going
to add support to SILGen to emit this. This ensures that when we assign into a
tuple var we initialize it with one instruction instead of doing it in pieces.
The problem with doing it in pieces is that when one is emitting diagnostics it
looks semantically like SILGen actually is emitting code for initializing in
pieces which could be an error.
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
This instructions marks the point where all let-fields of a class are initialized.
This is important to ensure the correctness of ``ref_element_addr [immutable]`` for let-fields,
because in the initializer of a class, its let-fields are not immutable, yet.
Codegen is the same, but `begin_dealloc_ref` consumes the operand and produces a new SSA value.
This cleanly splits the liferange to the region before and within the destructor of a class.
I was originally hoping to reuse mark_must_check for multiple types of checkers.
In practice, this is not what happened... so giving it a name specifically to do
with non copyable types makes more sense and makes the code clearer.
Just a pure rename.
The new instruction is needed for opaque values mode to allow values to
be extracted from tuples containing packs which will appear for example
as function arguments.
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`.
* Look through `begin_borrow` when analyzing closure values
* Treat non-escaping closures as trivial values when passed to a `partial_apply`
rdar://111046264
