Compute, update and handle borrowed-from instruction in various utilities and passes.
Also, used borrowed-from to simplify `gatherBorrowIntroducers` and `gatherEnclosingValues`.
Replace those utilities by `Value.getBorrowIntroducers` and `Value.getEnclosingValues`, which return a lazily computed Sequence of borrowed/enclosing values.
Under OSSA, the instruction may still be structurally responsible for consuming
its operand even if the result is dead, so we can't remove it without breaking
invariants.
More generally, this should probably apply to any instruction which consumes
one or more of its operands, has no side effects, and doesn't produce any
nontrivial results that require further consumption to keep the value alive.
I went with this targeted fix, since it addresses a problem that shows up
in practice (rdar://125381446) and the more general change appears to
disturb the optimizer pipeline while building the standard library.
drop_deinit forwards ownership while effectively stripping the deinitializer. It is similar to a type cast.
Fixes rdar://125590074 ([NonescapableTypes] Nonescapable types
cannot have deinits)
ClosureLifetimeFixup now emits mark_dependence [nonescaping]. Those should be
ignored by diagnostics. In the capture case, the dependence has already been
resolved, and may not match the SIL patterns that we expect for source-level
lifetime dependencies.
Fixes rdar://125375685 ([nonescapable] Fix lifetime-dependence diagnostics in the stdlib)
Don't treat StoreBorrow addresses as unknown bases. While they are never the base of a formal access, they are returned
as the AccessBase when querying the enclosing scope of an address.
Enable KeyPath/AnyKeyPath/PartialKeyPath/WritableKeyPath in Embedded Swift, but
for compile-time use only:
- Add keypath optimizations into the mandatory optimizations pipeline
- Allow keypath optimizations to look through begin_borrow, to make them work
even in OSSA.
- If a use of a KeyPath doesn't optimize away, diagnose in PerformanceDiagnostics
- Make UnsafePointer.pointer(to:) transparent to allow the keypath optimization
to happen in the callers of UnsafePointer.pointer(to:).
Treat mark_dependence [nonescaping] as a dependent value even if the dependence base does not have a recognizable
scope (e.g. a multiply-defined alloc_stack). This happens because ClosureLifetimeFixup creates redundant mark_dependence
instructions for partial_apply captures. We constantly need to work around this broken representation of nonescaping closures.
Add PartialApplyInst.hasNoescapeCapture
Add PartialApplyInst.mayEscape
Refactor DiagnoseInvalidEscapingCaptures. This may change functionality because tuples containing a noescape closure are now correctly recognized. Although I'm not sure such tupes can ever be captured directly.
