Having added these, I'm not entirely sure we couldn't just use
alloc_stack and dealloc_stack. Well, if we find ourselves adding
a lot of redundancy with those instructions (e.g. around DI), we
can always go back and rip these out.
- SILPackType carries whether the elements are stored directly
in the pack, which we're not currently using in the lowering,
but it's probably something we'll want in the final ABI.
Having this also makes it clear that we're doing the right
thing with substitution and element lowering. I also toyed
with making this a scalar type, which made it necessary in
various places, although eventually I pulled back to the
design where we always use packs as addresses.
- Pack boundaries are a core ABI concept, so the lowering has
to wrap parameter pack expansions up as packs. There are huge
unimplemented holes here where the abstraction pattern will
need to tell us how many elements to gather into the pack,
but a naive approach is good enough to get things off the
ground.
- Pack conventions are related to the existing parameter and
result conventions, but they're different on enough grounds
that they deserve to be separated.
For most uses, some access scopes must be "respected"--if an extended
value's original lifetime originally extends beyond an access scope, its
canonicalized lifetime must not end _within_ such scopes (although
ending before them is fine). Currently, to be conservative, the utility
applies this behavior to all access scopes.
For move-only values, however, lifetimes end at final consumes without
regard to access scopes.
Allow this behavior to be controlled by whether or not a
NonLocalAccessBlockAnalysis is provided to the utility in its
constructor.
rdar://104635319
When encountering inside a borrow scope a non-lexical move_value or a
move_value [lexical] where the borrowed value is itself already lexical,
delete the move_value and regard its uses as uses of the moved-from
value.
Previously, `begin_borrow [lexical]` were created during SILGen for
@owned arguments. Such borrows could be deleted if trivially dead,
which was the original reason why @owned arguments were considered
lexical and could not have their destroys hoisted.
Those borrows were however important during inlining because they would
maintain the lifetime of the owned argument. Unless of course the
borrow scope was trivially dead. In which case the owned argument's
lifetime would not be maintained. And if the caller's value was
non-lexical, destroys of the value could be hoisted over deinit
barriers.
Here, during inlining, `move_value [lexical]`s are introduced during
inlining whever the caller's value is non-lexical. This maintains the
lifetime of the owned argument even after inlining.
If a guaranted function argument is lexical, its lifetime must be
mainted during inlining. If the caller's value is already lexical,
no work is required to do the inlining.
If the callee is a non-generic thunk which calls a (not inlinable) generic function in the defining module,
it's more efficient to not devirtualize, but call the non-generic thunk - even though it's done through the witness table.
Example:
```
protocol P {
func f(x: [Int]) // not generic
}
struct S: P {
func f(x: some RandomAccessCollection<Int>) { ... } // generic
}
```
In the defining module, the generic conformance can be fully specialized (which is not possible in the client module, because it's not inlinable).
rdar://102623022
This attribute indicates that the given SILFunction has to be
added to "accessible functions" section and could be looked up
at runtime using a special API.
Load splitting converts an aggregate load into a set of subobject
loads. This is required at -Onone for exclusivity diagnostics.
We cannot preserve the original debug information by redirecting debug
info to the memory address, because that might result in incorrect
debug values if the memory is reused.
Before this fix, we "conservatively" drop debug info in those
cases. This fix preserves full debug info by keeping the original
aggregate load intact alongside the new subobject loads. To avoid
exclusivity violations, it create a new unsafe access scope for the
old load.
Fixes LLDB missing variables in certain case #62241
I am adding this to make it easy to determine if a SILFunction that is not inout
aliasable is captured. This is useful when emitting certain types of
diagnostics like I need to emit with move only.
In this case, we know the checked_cast_br will have a false outcome.
It is sufficient to transform checked_cast_br into a br and delete the success path.
Before this, we were trying to do an OSSA rauw the successarg which is incorrect.
Rather than inserting dealloc_stacks at the end of blocks in the
dominance frontier of the alloc_stack, walk backward in the block to the
last user (if any) and insert after that (or at the beginning of the
block if not). If the transitive uses aren't understood, just insert at
the end of the blocks as before.
Previously, the dealloc_stacks created for the alloc_stacks used to pass
@in_guaranteed arguments to on_stack closures were created after the
users of the closure. When SILGen created these alloc_stacks in the
same block as the users, this happened to work. Now that
AddressLowering creates such alloc_stacks elsewhere, this approach
results in invalid SIL.
Here, the dealloc_stacks are instead at the end of each block in the
dominance frontier of the alloc_stack.
Add TermInst::forwardedOperand.
Add SILArgument::forwardedTerminatorResultOperand. This API will be
moved into a proper TerminatorResult abstraction.
Remove getSingleTerminatorOperand, which could be misused because it's
not necessarilly forwarding ownership.
Remove the isTransformationTerminator API, which is not useful or well
defined.
Rewrite several instances of complex logic to handle block arguments
with the simple terminator result API. This defines away potential
bugs where we don't detect casts that perform implicit conversion.
Replace uses of the SILPhiArgument type and code that explicitly
handle block arguments. Control flow is irrelevant in these
situations. SILPhiArgument needs to be deleted ASAP. Instead, use
simple APIs like SILArgument::isTerminatorResult(). Eventually this
will be replaced by a TerminatorResult type.
When inlining a begin_apply, if one of the values is yielded by
guaranteed convention, if the yielded value is itself owned, borrow it
during inlining.
Doing so is necessary because users of the yielded value are expecting a
value with guaranteed ownership. For example, it's valid to
store_borrow such a value but not an owned value.
`getValue` -> `value`
`getValueOr` -> `value_or`
`hasValue` -> `has_value`
`map` -> `transform`
The old API will be deprecated in the rebranch.
To avoid merge conflicts, use the new API already in the main branch.
rdar://102362022
