When performing a dynamic cast to an existential type that satisfies
(Metatype)Sendable, it is unsafe to allow isolated conformances of any
kind to satisfy protocol requirements for the existential. Identify
these cases and mark the corresponding cast instructions with a new flag,
`[prohibit_isolated_conformances]` that will be used to indicate to the
runtime that isolated conformances need to be rejected.
With this approach, you cannot tell whether a parameter is addressable only
from the function type. Instead you need the SILValue that will be passed to the
call site.
Preserve conditionallyAddressableParamIndices independent of any
addressableParamIndices. The conditional dependencies are subject to change
based on type substitution.
The Protocol field isn't really necessary, because the conformance
stores the protocol. But we do need the substituted subject type
of the requirement, just temporarily, until an abstract conformance
stores its own subject type too.
* let `SIL.Type` conform to `TypeProperties` to share the implementation of common type properties between the AST types and `SIL.Type`
* call references to an `AST.Type` `rawType` (instead of just `type`)
* remove unneeded stuff
* add comments
InteriorLiveness has a new "visitInnerUses" mode used by DestroyHoisting. That
mode may visit dependent values, which was not valid for noescape
closures. ClosureLifetimeFixup inserts destroys of noescape closures after the
destroys of the captures. So following such dependent value could result in an
apparent use-after-destroy. This causes DestroyHoisting to insert redundant
destroys.
Fix: InteriorUses will conservatively only follow dependent values if they are
escapable. Non-escapable values, like noescape closures are now considered
escapes of the original value that the non-escapable value depends on. This can
be improved in the future, but we may want to rewrite ClosureLifetimeFixup first.
Fixes the root cause of: rdar://146142041
The `unchecked_ref_cast` is designed to be able to cast between
`Optional<ClassType>` and `ClassType`. We need to handle these cases by
checking if the type is optional and adjust the path accordingly.
* factor out common methods of AST Type/CanonicalType into a `TypeProperties` protocol.
* add more APIs to AST Type/CanoncialType.
* move `MetatypeRepresentation` from SIL.Type to AST.Type and implement it with a swift enum.
* let `Builder.createMetatype` get a CanonicalType as instance type, because the instance type must not be a lowered type.
The optional C++ type was bridged to a non-optional Swift type.
The correct way is to bridged the non-optional C++ type to the non-optional Swift type.
* getting the formal source and target types of casts
* `isFromVarDecl` and `usesMoveableValueDebugInfo` for AllocStackInst
* WitnessMethod APIs
* `TryApply.isNonAsync`
Check if an operand's instruction has been deleted in `UseList.next()`.
This allows to delete an instruction, which has two uses of a value, during use-list iteration.
This is necessary to fix a recent OSSA bug that breaks common occurrences on
mark_dependence [nonescaping]. Rather than reverting that change above, we make
forward progress toward implicit borrows scopes, as was the original intention.
In the near future, all InteriorPointer instructions will create an implicit
borrow scope. This means we have the option of not emitting extraneous
begin/end_borrow instructions around intructions like ref_element_addr,
open_existential, and project_box. After that, we can also migrate
GuaranteedForwarding instructions like tuple_extract and struct_extract.
We use the formal source type do decide whether a checked_cast_br is
known to succeed/fail. If we don't update it we loose that optimization
That is:
```
checked_cast_br AnyObject in %2 : X to X, bb1, bb2
```
Will not be simplified even though the operand and the destintation type
matches.
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
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.
This encourages AccessPathWalker clients to handle enclosing mark_deps. In
some cases, it is necessary. The accessBaseWithScopes API now provides both
nested begin_access and mark_dependence.
It defines (and implements) the `base` and `index` properties, which are used in the conforming classes `IndexRawPointerInst`, `IndexAddrInst` and `TailAddrInst`
