The copy operator has been implemented and doesn't use it. Remove
`Builtin.copy` and `_copy` as much as currently possible.
Source compatibility requires that `_copy` remain in the stdlib. It is
deprecated here and just uses the copy operator.
Handling old swiftinterfaces requires that `Builtin.copy` be defined.
Redefine it here as a passthrough--SILGen machinery will produce the
necessary copy_addr.
rdar://127502242
Changes in this CR add part of the, Swift based, Autodiff specific
closure specialization optimization pass. The pass does not modify any
code nor does it even exist in any of the optimization pipelines. The
rationale for pushing this partially complete optimization pass upstream
is to keep up with the breaking changes in the underlying Swift based
compiler infrastructure.
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.
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.
