Handle the special case of an guaranteed return value with no uses.
Fixes an assertion crash.
Unfortunately I don't have an isolated test case for this.
But this problem showed up in the `Interpreter/moveonly_read_modify_coroutines.swift` test with OSSA modules and will therefore be tested by this test once we enable OSSA modules.
The problem with `is_escaping_closure` was that it didn't consume its operand and therefore reference count checks were unreliable.
For example, copy-propagation could break it.
As this instruction was always used together with an immediately following `destroy_value` of the closure, it makes sense to combine both into a `destroy_not_escaped_closure`.
It
1. checks the reference count and returns true if it is 1
2. consumes and destroys the operand
Improves OSSALifetimeCompletion to handle trivial variables when running from
SILGenCleanup. This only affects lifetime dependence diagnostics.
For the purpose of lifetime diagnostics, trivial local variables are only valid
within their lexical scope. Sadly, SILGen only know how to insert cleanup code
on normal function exits. SILGenCleanup relies on lifetime completion to fix
lifetimes on dead end paths.
%var = move_value [var_decl]
try_apply %f() : $..., normal bb1, error error
error:
extend_lifetime %var <=== insert this
unreachable
This allows Span to depend on local unsafe pointers AND be used within
throwing closures:
_ = a.withUnsafeBufferPointer {
let buffer = $0
let view = Span(_unsafeElements: buffer)
return view.withUnsafeBufferPointer(\.count)
}
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.
Incomplete liveranges in the dead-end exit block can cause a missing adjacent phi-argument for a re-borrow if there is a borrow-scope is in the loop.
But even when we have complete lifetimes, it's probably not worth rotating a loop where the header block branches to a dead-end block.
Fixes a SIL verifier crash
When a keypath instruction was checked for serializability, its referenced function was
sometimes incorrectly deemed serializable when its referenced method had package or
public access level. This resulted in incorrectly serializing a function that dynamically
accesses a property on a generic type using key path. This PR fixes the issue by skipping
the access level check if the referenced function is determined to be un-serializable.
Resolves rdar://142950306
This adjusts the runtime function declaration handling to track the
owning module for the well known functions. This allows us to ensure
that we are able to properly identify if the symbol should be imported
or not when building the shared libraries. This will require a
subsequent tweak to allow for checking for static library linkage to
ensure that we do not mark the symbol as DLLImport when doing static
linking.
To determine where a lifetime ends within dead-end blocks,
OSSACanonicalizeOwned uses OSSACompleteLifetime's
visitAvailabilityBoundary. This API takes a liveness which it uses to
walk forward to the availability boundary. Specifically, the liveness
passed from OSSACanonicalizeOwned to OSSACompleteLifetime is a variation
of OSSACanonicalizeOwned's own liveness (it has destroys added).
There is a mismatch in the characteristics of livenesses created by
OSSACanonicalizeOwned and OSSACompleteLifetime: The former deals with
not only direct uses of a value but also uses of its copies; that
introduces the possibility for consuming uses in the middle of liveness.
The latter on the other hand deals only with uses of a single value
(nestedly, but at each level of nesting only a single value). Passing a
liveness from the former to the latter without handling this mismatch
is incorrect: OSSACompleteLifetime understands consuming uses to always
end a lifetime, even when they are in the middle of a copy-extended
liveness. The result is that OSSACompleteLifetime produces non-sensical
results when provided with such a liveness.
To address this, fixup the liveness passed from OSSACanonicalizeOwned to
OSSACompleteLifetime by demoting consuming uses that appear within
(that's to say _not_ on the boundary) of liveness to non-consuming uses.
rdar://142846936
The pass is structured to drain an instruction worklist and perform a
sequence of operations on each popped instruction. Extract that
sequence of operations into a new processInstruction function. Enables
testing the sequence on a single instruction.
Preserve ownership for empty non-trivial structs. This currently applies to
~Escapable structs. People often use empty structs to investigate language
behavior. They should behave just like a struct that wraps a
pointer.
Previously, this would crash later during OSSA lifetime completion:
Assertion failed: (isa<UnreachableInst>(block->getTerminator())),
function computeRegion, file OSSALifetimeCompletion.cpp.
Only generate code lazily for such functions, i.e. only if such a function is referenced from already generated code.
This is achieved by converting the SILLinkage for `public_external` functions to `internal` instead of `public in IRGenPrepare.
When visiting a consuming use of a move-only value (which can be
produced by a forwarding operation), the inner rewriter must bail out.
Otherwise, it would produce a copy of that move-only value.
rdar://142520491
Allow rewriting of arguments to bail out. This is necessary because not
all forwarding instructions allow rewriting of forward(copy) as
copy(forward) (e.g. when forward produces a move-only value).
So far we only checked the ownership of incoming values.
But even if the incoming instruction has no ownership, the argument may have.
This can happen with enums which are constructed with a non-payload case:
%1 = enum $Optional<C>, #Optional.none!enumelt
br bb3(%1)
bb1(%3 : @owned $Optional<C>):
Fixes an ownership verification error:
rdar://142506300
The operands to the original apply are cast via an ownership forwarding
instruction to the appropriate type for the rewritten apply.
```
%converted = convert_function %original to $(NewTy) -> ()
apply %converted(%operand)
```
->
```
%cast = cast %operand to $OriginalTy
apply %original(%cast)
```
Previously, when an original operand is owned but the new apply does not
consume that operand, the newly added cast would consume the original
operand (an owned value)--something the original code being replaced did
not do.
```
%converted = convert_function %original to $(NewTy) -> ()
apply %converted(%operand : @guaranteed)
// %operand remains available
```
->
```
%cast = cast %operand to $OriginalTy // consumes %operand!
apply %original(%cast : @guaranteed)
// %operand is not available!
```
This is incorrect for the complementary reasons that the result of the
cast is leaked and any uses of the original operand subsequent to the
new apply are uses-after-consume.
Here, this is fixed by borrowing the original operand before casting in
this case.
rdar://142570727
