In terms of the test suite the only difference is that we allow for non-Sendable
types to be returned from nonisolated functions. This is safe due to the rules
of rbi. We do still error when we return non-Sendable functions across isolation
boundaries though.
The reason that I am doing this now is that I am implementing a prototype that
allows for nonisolated functions to inherit isolation from their caller. This
would have required me to implement support both in Sema for results and
arguments in SIL. Rather than implement results in Sema, I just finished the
work of transitioning the result checking out of Sema and into SIL. The actual
prototype will land in a subsequent change.
rdar://127477211
Propagating array element values is done by load-simplification and redundant-load-elimination.
So ArrayElementPropagation is not needed anymore.
ArrayElementPropagation also replaced `Array.append(contentsOf:)` with individual `Array.append` calls.
This optimization is removed, because the benefit is questionably, anyway.
In most cases it resulted in a code size increase.
I am doing this since I discovered that we are not printing certain errors as
early as we used to (due to the refactoring I did here), which makes it harder
to see the errors that we are emitting while processing individual instructions
and before we run the actual dataflow.
A nice side-effect of this is that it will make it easy to dump the error in the
debugger rather than having to wait until the point in the code where the normal
logging takes place.
TLDR: Was looking at some performance traces and saw that we need to cache the
result of this value.
----
Specifically, I noticed that we were spending a lot of time computing this
operation. When I looked at the code I saw that we already had a cache along the
relevant code paths... but the cache was from equivalence class representative
-> state. Before we hit that cache, we were performing the work to map the value
to the equivalence class representative... so the work to perform the relevant
lookup from value -> state (which goes through the equivalence class
representative) was not just a hash table lookup. This operation makes it
cheaper by making it two cache lookups.
It may be possible to make this cheaper by redoing the actual mapping of
information so that we can go straight from value to state. I think it would be
slightly different since we would probably need to represent the state in a
separate array and map with indices... which is really just a more efficient
hash table. We could also use malloc/etc but lets not even talk about that.
rdar://139520959
This makes it so that one does not need to deal with the differences in text in
between the task isolated case and the actor isolated case. This is done by
swallowing the entire part of this message in one method rather than having the
caller do the work.
This is going to let me just pass through the error struct to the diagnostic
rather than having the CRTP and then constructing an info object per CRTP.
Currently, to make it easier to refactor, I changed the code in
TransferNonSendable to just take in the new error and call the current CRTP
routines. In the next commit, I am going to refactor TransferNonSendable.cpp
itself. This just makes it easier to test that I did not break anything.
The optimization replaces a `load [copy]` with a `load_borrow` if possible.
```
%1 = load [copy] %0
// no writes to %0
destroy_value %1
```
->
```
%1 = load_borrow %0
// no writes to %0
end_borrow %1
```
The new implementation uses alias-analysis (instead of a simple def-use walk), which is much more powerful.
rdar://115315849
In Embedded Swift, witness method lookup is done from specialized witness tables.
For this to work, the type of witness_method must be specialized as well.
Otherwise the method call would be done with wrong parameter conventions (indirect instead of direct).
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
MandatoryPerformanceOptimizations already did most of the vtable specialization work.
So it makes sense to remove the VTableSpecializerPass completely and do everything in MandatoryPerformanceOptimizations.
* add missing APIs
* bridge the entries as values and not as pointers
* add lookup functions in `Context`
* make WitnessTable.Entry.Kind enum cases lower case
The reason why is that we want to distinguish inbetween SILFunction's that are
marked as unspecified by SILGen and those that are parsed from textual SIL that
do not have any specified isolation. This will make it easier to write nice
FileCheck tests against SILGen output on what is the inferred isolation for
various items.
NFCI.
`SWIFT_IMPORT_UNSAFE` is an escape hatch that can be used to make the Swift compiler ignore its usual safety heuristics for C++ types.
`BridgedOwnedString` fits into the definition of a self-contained C++ type in Swift: it manages the lifetimes of its own fields.
This removes the usages of `SWIFT_IMPORT_UNSAFE` for C++ functions that return `BridgedOwnedString`, and annotates `BridgedOwnedString` as a self-contained type.
