Isolation fixes for closures and defer bodies #84181
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The first bug is that we weren't computing isolation correctly for nested defers. This is an unlikely pattern of code, but it's good to fix. The second bug is that getActorIsolationOfContext was looking through defers, but getActorIsolation itself was not. This was causing defer bodies to be emitted in SILGen without an isolation parameter, which meant that #isolation could not possibly provide the right value. Fixing this involves teaching SILGen that non-async functions can have nonisolated(nonsending) isolation, but that's relatively straightforward. This commit doesn't fix #isolation or adequately test SILGen, but that'll be handled in a follow-up.
closures. The fixes for initializers are just setting the stage for doing this properly: we should be able to just change the isolation computation in Sema and fix up the tests.
rjmccall
requested review from
hborla,
jckarter,
kavon,
ktoso,
slavapestov and
xedin
as code owners
|
@swift-ci Please test |
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oof, you're too fast @rjmccall – i tested locally and this variant appears to hit an issue in SILGen: func isolated_defer(_ iso: isolated (any Actor)) {
defer {
_ = #isolation
}
do {}
}would you expect this should have been handled by these changes? |
Ah, thanks for the test case. I can see how that would end up being handled differently within the compiler; I'll fix it. |
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I was trying to just fix a bug where
#isolationwasn't evaluated properly in closure expressions, but I realized that my fix had the potential to affect other cases, and my investigations revealed three other bugs:deferscopes, so nesteddeferbodies were being treated as non-isolated.deferbody did not look upwards at all, sodeferbodies were not treated as being isolated the same way as their parent function. I think we might have compensated for this in a lot of ways, but#isolationcould not possibly have evaluated correctly in caller-isolated contexts because thedeferbody simply didn't get the isolation passed to it.nonisolated(nonsending)functions was never returning caller-isolated, so these functions were not receiving implicit isolation parameters or using them correctly.I ended up going around in circles on the default-arguments bug a lot, and eventually I settled on implementing most of the structure necessary for fixing it but not actually fixing it. Changing the computation of the isolation should now just make everything in SILGen work.
The other bugs with closures and
defershould all be fixed.