Avoid query type in generics#69910

cjgillot · 2020-03-11T07:55:47Z

There are at the moment roughly 170 queries in librustc.
The way ty::query is structured, a lot of code is duplicated for each query.
I suspect this to be responsible for a part of librustc'c compile time.

This PR reduces the amount of code generic on the query,
replacing it by code generic on the key-value types.

This is split out of #69808,
and should not contain the perf regression.

cc #65031

rust-highfive · 2020-03-11T07:55:50Z

r? @eddyb

(rust_highfive has picked a reviewer for you, use r? to override)

Centril · 2020-03-11T08:24:15Z

r? @Zoxc

src/librustc/ty/query/plumbing.rs

Zoxc · 2020-03-11T13:28:03Z

I'm not sure how many unique key / value pairs we have for queries, if that isn't much lower than the total query count, this change isn't too impactful.

cjgillot · 2020-03-11T16:30:26Z

As a crude measurement, the number of instances of alloc_self_profile_query_strings_for_query_cache in the rlib goes from 201 to 148. QueryState::iter_results and <DefaultCache as QueryCache>::iter are called several times with closures, so go from 802 to 590 instances each.

Zoxc · 2020-03-12T07:15:19Z

That suggests that 26% of query key / value pairs are duplicates, so this is probably worthwhile.

src/librustc/ty/query/plumbing.rs

Zoxc · 2020-03-13T07:33:17Z

Why is my Erase trait added here?

cjgillot · 2020-03-13T07:48:54Z

I was experimenting with it yesterday, and somehow it ended up on the wrong branch. Sorry.

Zoxc · 2020-03-13T17:24:24Z

@bors try @rust-timer queue

rust-timer · 2020-03-13T17:24:26Z

Awaiting bors try build completion

bors · 2020-03-13T17:24:36Z

⌛ Trying commit 2bf1353 with merge 4adbc79...

Avoid query type in generics There are at the moment roughly 170 queries in librustc. The way ty::query is structured, a lot of code is duplicated for each query. I suspect this to be responsible for a part of librustc'c compile time. This PR reduces the amount of code generic on the query, replacing it by code generic on the key-value types. This is split out of #69808, and should not contain the perf regression. cc #65031

bors · 2020-03-13T20:41:39Z

☀️ Try build successful - checks-azure
Build commit: 4adbc79 (4adbc79bec9c18982551d4c0a11ed917425171bb)

rust-timer · 2020-03-13T20:41:41Z

Queued 4adbc79 with parent 54b7d21, future comparison URL.

rust-timer · 2020-03-14T00:10:31Z

Finished benchmarking try commit 4adbc79, comparison URL.

Zoxc · 2020-03-15T10:54:54Z

src/librustc/ty/query/plumbing.rs

+    pub(super) fn try_collect_active_jobs(
+        &self,
+        kind: DepKind,
+        make_query: impl Fn(C::Key) -> Query<'tcx> + Copy,


You could use &dyn for make_query here.

Zoxc · 2020-03-15T11:04:00Z

There are at the moment roughly 170 queries in librustc.
The way ty::query is structured, a lot of code is duplicated for each query.
I suspect this to be responsible for a part of librustc'c compile time.

I measured the compilation impact of the query system to be 25% of librustc's compile time 3. February.

src/librustc/ty/query/caches.rs

bors · 2020-03-15T23:50:44Z

☔ The latest upstream changes (presumably #68944) made this pull request unmergeable. Please resolve the merge conflicts.

cjgillot · 2020-03-16T10:33:13Z

Rebased.

Zoxc · 2020-03-17T16:54:42Z

I'd leave out the Bundle key commits since they add additional clone calls, otherwise this looks good.

cjgillot · 2020-03-17T19:09:41Z

Done.

Zoxc · 2020-03-17T19:23:51Z

@bors r+

bors · 2020-03-17T19:23:53Z

📌 Commit 8aa1328 has been approved by Zoxc

Avoid query type in generics There are at the moment roughly 170 queries in librustc. The way ty::query is structured, a lot of code is duplicated for each query. I suspect this to be responsible for a part of librustc'c compile time. This PR reduces the amount of code generic on the query, replacing it by code generic on the key-value types. This is split out of rust-lang#69808, and should not contain the perf regression. cc rust-lang#65031

@ghost

Rollup of 6 pull requests Successful merges: - rust-lang#69497 (Don't unwind when hitting the macro expansion recursion limit) - rust-lang#69901 (add #[rustc_layout(debug)]) - rust-lang#69910 (Avoid query type in generics) - rust-lang#69955 (Fix abort-on-eprintln during process shutdown) - rust-lang#70032 (put type params in front of const params in generics_of) - rust-lang#70119 (rustc: use LocalDefId instead of DefId in TypeckTables.) Failed merges: r? @ghost

Zoxc · 2020-03-24T04:34:38Z

src/librustc/ty/query/caches.rs

        &self,
-        state: &'tcx QueryState<'tcx, Q>,
+        state: &'tcx QueryState<'tcx, Self>,
        get_cache: GetCache,


Now that you connected up the types, you should be able to just get rid of get_cache: GetCache.

Zoxc · 2020-03-24T04:35:43Z

src/librustc/ty/query/plumbing.rs

+impl<'tcx, C: QueryCache> QueryState<'tcx, C> {
+    pub(super) fn get_lookup<K2: Hash>(
+        &'tcx self,
+        key: &K2,


K2 can now be C::Key.

@Zoxc

Move the query system to a dedicated crate The query system `rustc::ty::query` is split out into the `rustc_query_system` crate. Some commits are unformatted, to ease rebasing. Based on rust-lang#67761 and rust-lang#69910. r? @Zoxc

rust-highfive assigned eddyb Mar 11, 2020

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Mar 11, 2020

rust-highfive assigned Zoxc and unassigned eddyb Mar 11, 2020

cjgillot force-pushed the polym branch from 93146b9 to 858d8fa Compare March 11, 2020 10:46

Zoxc reviewed Mar 11, 2020

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cjgillot force-pushed the polym branch from ca8fcc3 to c3c5e93 Compare March 12, 2020 22:22

Zoxc reviewed Mar 13, 2020

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cjgillot force-pushed the polym branch from 11f03fa to 2bf1353 Compare March 13, 2020 07:48

Zoxc reviewed Mar 15, 2020

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cjgillot force-pushed the polym branch from 3effbd6 to 474e8ba Compare March 15, 2020 13:18

Remove __query_compute module.

0bf5cae

cjgillot added 5 commits March 16, 2020 09:48

Remove Q parameter from try_get_cached.

5dc7c2e

Offload try_collect_active_jobs.

7d84f4f

Simplify type aliases.

7309b3c

Make QueryCache parameters associated types.

3abd475

Remove QueryState type alias.

5557407

cjgillot force-pushed the polym branch from 526236d to 2485ebf Compare March 16, 2020 10:22

Make stuff private.

8aa1328

cjgillot force-pushed the polym branch from 2485ebf to 8aa1328 Compare March 17, 2020 19:08

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Mar 17, 2020

Centril mentioned this pull request Mar 19, 2020

Rollup of 5 pull requests #70141

Closed

cjgillot mentioned this pull request Mar 19, 2020

Move the query system to a dedicated crate #70162

Merged

Dylan-DPC-zz mentioned this pull request Mar 20, 2020

Rollup of 7 pull requests #70198

Closed

Dylan-DPC-zz mentioned this pull request Mar 21, 2020

Rollup of 6 pull requests #70222

Merged

bors merged commit 8deeac1 into rust-lang:master Mar 21, 2020

cjgillot deleted the polym branch March 21, 2020 17:52

Zoxc reviewed Mar 24, 2020

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