Some notes:
This is not emitted by SILGen. This is just intended to be used so I can write
SIL test cases for transfer non sendable. I did this by adding an
ActorIsolationCrossing field to all FullApplySites rather than adding it into
the type system on a callee. The reason that this makes sense from a modeling
perspective is that an actor isolation crossing is a caller concept since it is
describing a difference in between the caller's and callee's isolation. As a
bonus it makes this a less viral change.
For simplicity, I made it so that the isolation is represented as an optional
modifier on the instructions:
apply [callee_isolation=XXXX] [caller_isolation=XXXX]
where XXXX is a printed representation of the actor isolation.
When neither callee or caller isolation is specified then the
ApplyIsolationCrossing is std::nullopt. If only one is specified, we make the
other one ActorIsolation::Unspecified.
This required me to move ActorIsolationCrossing from AST/Expr.h ->
AST/ActorIsolation.h to work around compilation issues... Arguably that is where
it should exist anyways so it made sense.
rdar://118521597
* `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
SILGen optimizes creation of closure down a thin function when it has
no captures:
%1 = thin_to_thick_function %0
: $@convention(thin) () -> () to $@callee_guaranteed () -> ()
ValueOwnership.cpp has a sketchy optimization that treat the result
like a trivial type, even though it is not:
> CONSTANT_OWNERSHIP_INST(None, ThinToThickFunction)
commit 8c5737d1d5
Date: Fri Oct 23 15:12:18 2020 -0700
[ownership] Change thin_to_thick function to always produce a none value.
This creates a mismatch between the SILType and the SILValue
ownership. This is not a coherent design--we have a similar problem
with enums which is endlessly buggy--but reverting the decision will
be hard. Instead, I'll hack the memory verifier to silence this case.
Fixes rdar://115735132 (Lifetime verifier error with opaque return
type and closure)
To verify if a function may read from an indirect argument, don't use AliasAnalysis.
Instead use the CalleeCache to get the list of callees of an apply instruction.
Then use a simple call-back into the swift Function to check if a callee has any relevant memory effect set.
This avoids a dependency from SIL to the Optimizer.
It fixes a linker error when building some unit tests in debug.
`getRootLocalArchetypeDef()` may return a `PlaceholderValue` which makes the
`cast<SingleValueInstruction>` invalid. Use `dyn_cast` and then update the
callers of `getRootLocalArchetypeDefInst()` to handle `nullptr`.
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
Introduce SILGen support for reabstractions thunks that change the
error, between indirect and direct errors as well as conversions
amongst error types (e.g., from concrete to `any Error`).
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.
Unlike in regular swift, The class_method instruction references the specialized version of a class method.
This must be handled in ReabstractionInfo: it needs to work without a concrete callee SIL function.
Also, the SILVerifier must handle the case that a class_method instruction references a specialized method.
This instruction was given forwarding ownership in the original OSSA
implementation. That will obviously lead to memory leaks. Remove
ownership from this instruction and verify that it is never used for
non-trivial types.
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
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.
- VTableSpecializer, a new pass that synthesizes a new vtable per each observed concrete type used
- Don't use full type metadata refs in embedded Swift
- Lazily emit specialized class metadata (LazySpecializedClassMetadata) in IRGen
- Don't emit regular class metadata for a class decl if it's generic (only emit the specialized metadata)
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.
Trivial enum cases in a memory location don't need to be destroyed.
Don't require that the store to such a memory location is statically known as a trivial enum case.
Instead just require that it's below a switch_enum successor for a trivial case.
Fixes a false alarm.
rdar://114274714
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.
