This ensures that in cases like the following:
+func testNoncopyableNonsendableStructWithNonescapingMainActorAsync() {
+ let x = NoncopyableStructNonsendable() <=========
+ let _ = {
+ nonescapingAsyncClosure { @MainActor in
+ useValueNoncopyable(x) // expected-warning {{sending 'x' risks causing data races}}
+ // expected-note @-1 {{task-isolated 'x' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later nonisolated uses}}
+ }
+ }
+}
We emit the diagnostic on the use instead of the <=====.
rdar://166347485
I have noticed over time when working on the command line, we often times
highlight too large of an expression due to the locations provided to us by
earlier parts of the compiler. This isn't technically necessary and the
following doesn't look nice... so remove it.
```
test5.swift:171:16: error: sending 'x' risks causing data races [#SendingRisksDataRace]
169 | let _ = {
170 | nonescapingAsyncUse { @MainActor in
171 | _ _ _ _ _u_s_e_V_a_l_u_e_(_x_)
| |- error: sending 'x' risks causing data races [#SendingRisksDataRace]
| `- note: task-isolated 'x' is captured by a main actor-isolated closure. main actor-isolated uses in closure may race against later nonisolated uses
172 | }
173 | }
```
We may see undef closure captures in ClosureLifetimeFixup since
it is a mandatory pass that runs on invalid code as well.
This could sometimes hang the compiler while running `insertDeallocOfCapturedArguments`
in release builds.
This change adds a bailout when we see an undef closure capture to avoid running into this issue.
When an owned value has no lifetime ending uses it means that it is in a dead-end region.
We must not remove and inserting compensating destroys for it because that would potentially destroy the value too early.
Initialization of an object might be cut off and removed after a dead-end loop or an `unreachable`.
In this case a class destructor would see uninitialized fields.
Fixes a mis-compile
https://github.com/swiftlang/swift/issues/85851
rdar://165876726
If followed by a dead infinite loop, the array initialization might have beed removed.
Therefore when inserting a compensating destroy of the array buffer can lead to a crash.
https://github.com/swiftlang/swift/issues/85851
rdar://165876726
DeadCodeElimination can remove instructions including their destroys and then insert compensating destroys at a new place.
This is effectively destroy-hoisting which doesn't respect deinit-barriers.
Disable removing and re-creating `destroy_value` instructions. This is done by other optimizations.
The InstructionDeleter can remove instructions including their destroys and then insert compensating destroys at a new place.
This is effectively destroy-hoisting which doesn't respect deinit-barriers. Therefore it's not done for lexical lifetimes.
However, since https://github.com/swiftlang/swift/pull/85334, the optimizer should treat _all_ lifetimes as fixed and not only lexical lifetimes.
This change adds a `assumeFixedLifetimes` flag to InstructionDeleter which is on by default.
Only mandatory passes (like OSLogOptimization) should turn this off.
Specifically, improved debug info retention in:
* tryReplaceRedundantInstructionPair,
* splitAggregateLoad,
* TempLValueElimination,
* Mem2Reg,
* ConstantFolding.
The changes to Mem2Reg allow debug info to be retained in the case tested by
self-nostorage.swift in -O builds, so we have just enabled -O in that file
instead of writing a new test for it.
We attempted to add a case to salvageDebugInfo for unchecked_enum_data, but it
caused crashes in Linux CI that we were not able to reproduce.
Refactor certain functions to make them simpler. and avoid calling
AST.Type.loweredType, which can fail. Instead, access the types of the
function's (SIL) arguments directly.
Correctly handle exploding packs that contain generic or opaque types by using
AST.Type.mapOutOfEnvironment().
@substituted types cause the shouldExplode predicate to be unreliable for AST
types, so restrict it to just SIL.Type. Add test cases for functions that have
@substituted types.
Re-enable PackSpecialization in FunctionPass pipeline.
Add a check to avoid emitting a destructure_tuple of the original function's
return tuple when it is void/().
We cannot compute the liverange of a value if it bit-wise escapes.
This fixes a mis-compile in copy-propagation which hoists a destroy_value over a use of the escaped value when lexical liveranges are disabled.
The test case is a simplified SIL sequence from the stdlib core where this problem shows up, because we build the stdlib core with disabled lexical liveranges.
This is needed in Embedded Swift because the `witness_method` convention requires passing the witness table to the callee.
However, the witness table is not necessarily available.
A witness table is only generated if an existential value of a protocol is created.
This is a rare situation because only witness thunks have `witness_method` convention and those thunks are created as "transparent" functions, which means they are always inlined (after de-virtualization of a witness method call).
However, inlining - even of transparent functions - can fail for some reasons.
This change adds a new EmbeddedWitnessCallSpecialization pass:
If a function with `witness_method` convention is directly called, the function is specialized by changing the convention to `method` and the call is replaced by a call to the specialized function:
```
%1 = function_ref @callee : $@convention(witness_method: P) (@guaranteed C) -> ()
%2 = apply %1(%0) : $@convention(witness_method: P) (@guaranteed C) -> ()
...
sil [ossa] @callee : $@convention(witness_method: P) (@guaranteed C) -> () {
...
}
```
->
```
%1 = function_ref @$e6calleeTfr9 : $@convention(method) (@guaranteed C) -> ()
%2 = apply %1(%0) : $@convention(method) (@guaranteed C) -> ()
...
// specialized callee
sil shared [ossa] @$e6calleeTfr9 : $@convention(method) (@guaranteed C) -> () {
...
}
```
Fixes a compiler crash
rdar://165184147
This peephole optimization didn't consider that an alloc_stack of an enum can be overridden by another value.
The fix is to remove this peephole optimization at all because it is already covered by `optimizeEnum` in alloc_stack simplification.
Fixes a miscompile
https://github.com/swiftlang/swift/issues/85687
rdar://165374568
It eliminates dead access scopes if they are not conflicting with other scopes.
Removes:
```
%2 = begin_access [modify] [dynamic] %1
... // no uses of %2
end_access %2
```
However, dead _conflicting_ access scopes are not removed.
If a conflicting scope becomes dead because an optimization e.g. removed a load, it is still important to get an access violation at runtime.
Even a propagated value of a redundant load from a conflicting scope is undefined.
```
%2 = begin_access [modify] [dynamic] %1
store %x to %2
%3 = begin_access [read] [dynamic] %1 // conflicting with %2!
%y = load %3
end_access %3
end_access %2
use(%y)
```
After redundant-load-elimination:
```
%2 = begin_access [modify] [dynamic] %1
store %x to %2
%3 = begin_access [read] [dynamic] %1 // now dead, but still conflicting with %2
end_access %3
end_access %2
use(%x) // propagated from the store, but undefined here!
```
In this case the scope `%3` is not removed because it's important to get an access violation error at runtime before the undefined value `%x` is used.
This pass considers potential conflicting access scopes in called functions.
But it does not consider potential conflicting access in callers (because it can't!).
However, optimizations, like redundant-load-elimination, can only do such transformations if the outer access scope is within the function, e.g.
```
bb0(%0 : $*T): // an inout from a conflicting scope in the caller
store %x to %0
%3 = begin_access [read] [dynamic] %1
%y = load %3 // cannot be propagated because it cannot be proved that %1 is the same address as %0
end_access %3
```
All those checks are only done for dynamic access scopes, because they matter for runtime exclusivity checking.
Dead static scopes are removed unconditionally.
Empty access scopes can be a result of e.g. redundant-load-elimination.
It's still important to keep those access scopes to detect access violations.
Even if the load is physically not done anymore, in case of a conflicting access a propagated load is still wrong and must be detected.
rdar://164571252
Empty access scopes can be a result of e.g. redundant-load-elimination.
It's still important to keep those access scopes to detect access violations.
Even if the load is physically not done anymore, in case of a conflicting access a propagated load is still wrong and must be detected.
rdar://164571252
Although this error can only happen when tinkering with the stdlib's runtime functions, it's nice to get a readable error message. So far, the compiler just crashed later without a hint to the original problem.
This code was not consulting SILFunctionConventions, so it was
passing things indirect when they are not in sil-opaque-values.
This fixes callers as well to ensure they pass arguments and
results correctly in both modes.
Teach SIL type lowering to recursively track custom vs. default deinit status.
Determine whether each type recursively only has default deinitialization. This
includes any recursive deinitializers that may be invoked by releasing a
reference held by this type.
If a type only has default deinitialization, then the deinitializer cannot
have any semantically-visible side effects. It cannot write to any memory
The method originally special-cased logic that would provide a
meaningful speedup and simplification, but IIUC the history, this has no
longer been the case for many years, so we might as well remove it to
make the code more straightforward.
