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.
It defines (and implements) the `base` and `index` properties, which are used in the conforming classes `IndexRawPointerInst`, `IndexAddrInst` and `TailAddrInst`
* `users`: maps from a sequence of operands to a sequence of instructions
* `users(ofType:)` : as `users`, but filters users of a certain instruction type
* `Value.users`: = `Value.uses.users`
I am adding this instruction to express artificially that two non-Sendable
values should be part of the same region. It is meant to be used in cases where
due to unsafe code using Sendable, we stop propagating a non-Sendable dependency
that needs to be made in the same region of a use of said Sendable value. I
included an example in ./docs/SIL.rst of where this comes up with @out results
of continuations.
For now this will only be used for HopToMainActorIfNeeded thunks. I am creating
this now since in the past there has only been one option for creating
thunks... to create the thunk in SILGen using SILGenThunk. This code is hard to
test and there is a lot of it. By using an instruction here we get a few benefits:
1. We decouple SILGen from needing to generate new kinds of thunks. This means
that SILGenThunk does not need to expand to handle more thunks.
2. All thunks implemented via ThunkInst will be easy to test in a decoupled way
with SIL tests.
3. Even though this stabilizes the patient, we still have many thunks in SILGen
and various parts of the compiler. Over time, we can swap to this model,
allowing us to hopefully eventually delete SILGenThunk.
As the optimizer uses more and more AST stuff, it's now time to create an "AST" module.
Initially it defines following AST datastructures:
* declarations: `Decl` + derived classes
* `Conformance`
* `SubstitutionMap`
* `Type` and `CanonicalType`
Some of those were already defined in the SIL module and are now moved to the AST module.
This change also cleans up a few things:
* proper definition of `NominalTypeDecl`-related APIs in `SIL.Type`
* rename `ProtocolConformance` to `Conformance`
* use `AST.Type`/`AST.CanonicalType` instead of `BridgedASTType` in SIL and the Optimizer
Some requirement machine work
Rename requirement to Value
Rename more things to Value
Fix integer checking for requirement
some docs and parser changes
Minor fixes
It indicates that the value's lifetime continues to at least this point.
The boundary formed by all consuming uses together with these
instructions will encompass all uses of the value.
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.
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.
To make the ScopedInstruction abstraction useful and formalize to use-points of scoped operations.
This is specifically for scoped operations that use their operands up to the end of their scope.
This is not for the many instructions that introduce scoped lifetimes. Allocations are not considered scoped
operations. Every owned value has a scoped lifetime just like an allocation, but the scope-ending instructions are not
considered use points.
These instructions carry lifetime dependence from a single operand to a single result. They are not forwarding
instructions because we use them to indicate the boundaries of a forwarded lifetime.
* add ForwardingInstruction conformances to missing forwarding instruction classes
* move all the forwarding instruction conformance definitions into ForwardingInstructions.swift
* remove the default implementations of the requirements, so that every instruction needs to specify them
In preparation for inserting mark_dependence instructions for lifetime
dependencies early, immediately after SILGen. That will simplify the
implementation of borrowed arguments.
Marking them unresolved is needed to make OSSA verification
conservative until lifetime dependence diagnostics runs.
