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Compute NLL loan scopes using the polonius model #113218
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@matthewjasper there are still things in there that I'd like to clean up, (e.g. I'm currently seeing whether some of the reachability computation can be done in liveness, and may try to make the look a bit more like the refactored CFG traversal) but I don't think they're absolutely necessary and won't change the core of the PR: you could already take a look whether you approve of the direction. It'd be greatly appreciated 🙏 |
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Overall this approach seems fine as a first step.
It would be nice to have this "rebased" on the changes in #111759 to make determining the differences easier.
Thanks for taking a look.
Sure, I'll try to tackle that soon. It'll still have to be somewhat different, compared to diffing over https://github.com/lqd/rust/blob/eaddc3707520988f8bc2d267cb192d2f0c63ee80/compiler/rustc_borrowck/src/dataflow.rs#L155-L231 prior to the refactor and where it's easier to see that basically only the |
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this allows to opt into using the legacy version or the in-tree prototype
let's see the hit liveness takes to do additional checks on whether polonius is enabled @bors try @rust-timer queue |
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Compute NLL loan scopes using the polonius model Draft PR to guide discussion for this monday's types team meeting, where the plan is to read this and review as a group. For a *location-insensitive* analysis (that is, without expressiveness improvements for users yet), this PR implements loans going out of scope using reachability and liveness, rather than checking if the issuing region's values contain a given CFG point. This is equivalent to NLL scopes and computes the same data. There are a few fixmes left, and I'll still work on them before the meeting. A couple of notes: - I started prototyping this a while ago so it follows the structure of the _previous_ NLL `OutOfScopePrecomputer`, before the couple recent refactors. They probably could/should look the same instead. - there are some assumptions about placeholders, free regions, and member constraints that I think hold, and they're documented in the code - this passes all the UI tests with `-Zpolonius=next` -- though the additional work done can be felt on the huge numeric/float tests, but the perf is [not terrible](rust-lang#112432 (comment)) and there are a bunch of ways to improve it in the future. (cc `@matthewjasper` since you asked to be pinged about it) r? `@ghost`
☀️ Try build successful - checks-actions |
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Finished benchmarking commit (263b07f): comparison URL. Overall result: ❌ regressions - ACTION NEEDEDBenchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf. Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @bors rollup=never Instruction countThis is a highly reliable metric that was used to determine the overall result at the top of this comment.
Max RSS (memory usage)This benchmark run did not return any relevant results for this metric. CyclesThis benchmark run did not return any relevant results for this metric. Binary sizeThis benchmark run did not return any relevant results for this metric. Bootstrap: 621.055s -> 621.438s (0.06%) |
This also should partly be noise: cachegrind only shows a 0.1% diff on helloworld. And the noise bumps shown below from the last few days, are to similar icounts within 0.03% of this run. Similar noise on these benchmarks, with the same magnitude, is also currently present in other PRs, e.g. here. That seems acceptable at least to start an initial review. @rustbot ready |
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I don't think there's anything here that would cause me not to feel comfortable r+ing, but some thoughts nonetheless :)
// FIXME: if the issuing region `i` can reach a live region `r` at point `p`, and `r` is | ||
// live at point `q`, then it's guaranteed that `i` would reach `r` at point `q`. | ||
// Reachability is location-insensitive, and we could take advantage of that, by jumping | ||
// to a further point than just the next statement: we can jump to the furthest point | ||
// within the block where `r` is live. |
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Could certainly do a binary search here - but I'm not sure the complexity would be helpful. What could be interesting is going from end to start (depends how often we expect loans to be live at the end of a block versus dying within (and where)
@bors r+ I think we can get this into tree. It's still behind a flag, so not worried. |
@bors p=6 moving over my rollup |
☀️ Test successful - checks-actions |
Finished benchmarking commit (c1691db): comparison URL. Overall result: ✅ improvements - no action needed@rustbot label: -perf-regression Instruction countThis is a highly reliable metric that was used to determine the overall result at the top of this comment.
Max RSS (memory usage)ResultsThis is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.
CyclesThis benchmark run did not return any relevant results for this metric. Binary sizeThis benchmark run did not return any relevant results for this metric. Bootstrap: 628.128s -> 628.448s (0.05%) |
48: Pull upstream master 2023 10 12 r=tshepang a=Dajamante * rust-lang/rust#113487 * rust-lang/rust#116506 * rust-lang/rust#116448 * rust-lang/rust#116640 * rust-lang/rust#116627 * rust-lang/rust#116597 * rust-lang/rust#116436 * rust-lang/rust#116315 * rust-lang/rust#116219 * rust-lang/rust#113218 * rust-lang/rust#115937 * rust-lang/rust#116014 * rust-lang/rust#116623 * rust-lang/rust#112818 * rust-lang/rust#115948 * rust-lang/rust#116622 * rust-lang/rust#116621 * rust-lang/rust#116612 * rust-lang/rust#116611 * rust-lang/rust#116530 * rust-lang/rust#95967 * rust-lang/rust#116578 * rust-lang/rust#113915 * rust-lang/rust#116605 * rust-lang/rust#116574 * rust-lang/rust#116560 * rust-lang/rust#116559 * rust-lang/rust#116503 * rust-lang/rust#116444 * rust-lang/rust#116250 * rust-lang/rust#109422 * rust-lang/rust#116598 * rust-lang/rust#116596 * rust-lang/rust#116595 * rust-lang/rust#116589 * rust-lang/rust#116586 * rust-lang/rust#116551 * rust-lang/rust#116409 * rust-lang/rust#116548 * rust-lang/rust#116366 * rust-lang/rust#109882 * rust-lang/rust#116497 * rust-lang/rust#116532 * rust-lang/rust#116569 * rust-lang/rust#116561 * rust-lang/rust#116556 * rust-lang/rust#116549 * rust-lang/rust#116543 * rust-lang/rust#116537 * rust-lang/rust#115882 * rust-lang/rust#116142 * rust-lang/rust#115238 * rust-lang/rust#116533 * rust-lang/rust#116096 * rust-lang/rust#116468 * rust-lang/rust#116515 * rust-lang/rust#116454 * rust-lang/rust#116183 * rust-lang/rust#116514 * rust-lang/rust#116509 * rust-lang/rust#116487 * rust-lang/rust#116486 * rust-lang/rust#116450 * rust-lang/rust#114623 * rust-lang/rust#116416 * rust-lang/rust#116437 * rust-lang/rust#100806 * rust-lang/rust#116330 * rust-lang/rust#116310 * rust-lang/rust#115583 * rust-lang/rust#116457 * rust-lang/rust#116508 * rust-lang/rust#109214 * rust-lang/rust#116318 * rust-lang/rust#116501 * rust-lang/rust#116500 * rust-lang/rust#116458 * rust-lang/rust#116400 * rust-lang/rust#116277 * rust-lang/rust#114709 * rust-lang/rust#116492 * rust-lang/rust#116484 * rust-lang/rust#116481 * rust-lang/rust#116474 * rust-lang/rust#116466 * rust-lang/rust#116423 * rust-lang/rust#116297 * rust-lang/rust#114564 * rust-lang/rust#114811 * rust-lang/rust#116489 * rust-lang/rust#115304 Co-authored-by: Peter Hall <peter.hall@hyperexponential.com> Co-authored-by: Emanuele Vannacci <emanuele.vannacci@gmail.com> Co-authored-by: Neven Villani <vanille@crans.org> Co-authored-by: Alex Macleod <alex@macleod.io> Co-authored-by: Tamir Duberstein <tamird@gmail.com> Co-authored-by: Eduardo Sánchez Muñoz <eduardosm-dev@e64.io> Co-authored-by: koka <koka.code@gmail.com> Co-authored-by: bors <bors@rust-lang.org> Co-authored-by: Philipp Krones <hello@philkrones.com> Co-authored-by: Camille GILLOT <gillot.camille@gmail.com> Co-authored-by: Esteban Küber <esteban@kuber.com.ar> Co-authored-by: Ralf Jung <post@ralfj.de>
48: Pull upstream master 2023 10 12 r=tshepang a=Dajamante * rust-lang/rust#113487 * rust-lang/rust#116506 * rust-lang/rust#116448 * rust-lang/rust#116640 * rust-lang/rust#116627 * rust-lang/rust#116597 * rust-lang/rust#116436 * rust-lang/rust#116315 * rust-lang/rust#116219 * rust-lang/rust#113218 * rust-lang/rust#115937 * rust-lang/rust#116014 * rust-lang/rust#116623 * rust-lang/rust#112818 * rust-lang/rust#115948 * rust-lang/rust#116622 * rust-lang/rust#116621 * rust-lang/rust#116612 * rust-lang/rust#116611 * rust-lang/rust#116530 * rust-lang/rust#95967 * rust-lang/rust#116578 * rust-lang/rust#113915 * rust-lang/rust#116605 * rust-lang/rust#116574 * rust-lang/rust#116560 * rust-lang/rust#116559 * rust-lang/rust#116503 * rust-lang/rust#116444 * rust-lang/rust#116250 * rust-lang/rust#109422 * rust-lang/rust#116598 * rust-lang/rust#116596 * rust-lang/rust#116595 * rust-lang/rust#116589 * rust-lang/rust#116586 * rust-lang/rust#116551 * rust-lang/rust#116409 * rust-lang/rust#116548 * rust-lang/rust#116366 * rust-lang/rust#109882 * rust-lang/rust#116497 * rust-lang/rust#116532 * rust-lang/rust#116569 * rust-lang/rust#116561 * rust-lang/rust#116556 * rust-lang/rust#116549 * rust-lang/rust#116543 * rust-lang/rust#116537 * rust-lang/rust#115882 * rust-lang/rust#116142 * rust-lang/rust#115238 * rust-lang/rust#116533 * rust-lang/rust#116096 * rust-lang/rust#116468 * rust-lang/rust#116515 * rust-lang/rust#116454 * rust-lang/rust#116183 * rust-lang/rust#116514 * rust-lang/rust#116509 * rust-lang/rust#116487 * rust-lang/rust#116486 * rust-lang/rust#116450 * rust-lang/rust#114623 * rust-lang/rust#116416 * rust-lang/rust#116437 * rust-lang/rust#100806 * rust-lang/rust#116330 * rust-lang/rust#116310 * rust-lang/rust#115583 * rust-lang/rust#116457 * rust-lang/rust#116508 * rust-lang/rust#109214 * rust-lang/rust#116318 * rust-lang/rust#116501 * rust-lang/rust#116500 * rust-lang/rust#116458 * rust-lang/rust#116400 * rust-lang/rust#116277 * rust-lang/rust#114709 * rust-lang/rust#116492 * rust-lang/rust#116484 * rust-lang/rust#116481 * rust-lang/rust#116474 * rust-lang/rust#116466 * rust-lang/rust#116423 * rust-lang/rust#116297 * rust-lang/rust#114564 * rust-lang/rust#114811 * rust-lang/rust#116489 * rust-lang/rust#115304 Co-authored-by: Emanuele Vannacci <emanuele.vannacci@gmail.com> Co-authored-by: Neven Villani <vanille@crans.org> Co-authored-by: Alex Macleod <alex@macleod.io> Co-authored-by: Tamir Duberstein <tamird@gmail.com> Co-authored-by: Eduardo Sánchez Muñoz <eduardosm-dev@e64.io> Co-authored-by: koka <koka.code@gmail.com> Co-authored-by: bors <bors@rust-lang.org> Co-authored-by: Philipp Krones <hello@philkrones.com> Co-authored-by: Camille GILLOT <gillot.camille@gmail.com> Co-authored-by: Esteban Küber <esteban@kuber.com.ar> Co-authored-by: Ralf Jung <post@ralfj.de> Co-authored-by: ShE3py <52315535+she3py@users.noreply.github.com>
For a location-insensitive analysis (that is, without expressiveness improvements for users yet), this PR implements loans going out of scope using reachability and liveness, rather than checking if the issuing region's values contain a given CFG point. This is equivalent to NLL scopes and computes the same data.
r? @matthewjasper
A couple of notes:
-Zpolonius=next
-- the perf is not terrible and there are a bunch of ways to improve it in the future.