Clean up query macros for `cache_on_disk_if` #151943

Zalathar · 2026-02-01T09:50:06Z

This PR aims to make the macros for dealing with cache_on_disk_if a bit easier to read and work with.

There should be no change to compiler behaviour.

rustbot · 2026-02-01T09:50:12Z

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petrochenkov · 2026-02-02T16:01:22Z

compiler/rustc_macros/src/query.rs

+#[derive(Default)]
+struct HelperTokenStreams {
+    descs_stream: proc_macro2::TokenStream,
+    cache_on_disk_if_fns_stream: proc_macro2::TokenStream,


Is there multiple functions/descriptions, or one function/description?
There's some naming inconsistency, query_description_stream below says that it's one, but "descs" says that there are multiple.

Each stream contains multiple descriptions or multiple functions (0-1 of each per query).

The existing name query_description_stream is misleading; I'll update this PR to change it.

Zoxc · 2026-02-03T06:26:35Z

compiler/rustc_macros/src/query.rs

+
+        // FIXME(Zalathar): Instead of declaring these functions directly, can
+        // we put them in a macro and then expand that macro downstream in
+        // `rustc_query_impl`, where the functions are actually used?


We kind of want to keep rustc_query_impl small (for compile-time reasons), so having it point to functions (which won't be inlined) in rustc_middle isn't terrible.

I was thinking that we also want to keep rustc_middle small (since it's a bottleneck for most other compiler crates), though I don't have a strong sense of how shuffling things between the two crates affects overall build times (especially with metadata pipelining).

Yes, but there's other way to reduce rustc_middle (particularly if other crates can also define queries). rustc_query_impl will mostly keep growing as we add queries.

The primary purpose of rustc_query_impl is to allow rustc_middle to be smaller.

If we wanted to improve query-impl build times by enabling more parallelism, we wouldn't do so by moving code into middle; we'd move it into an intermediate crate between the two.

So I don't think keeping query-impl small is a reason to not move code from middle to query-impl.

rustbot · 2026-02-05T05:46:49Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

tiif · 2026-02-08T13:23:41Z

Hi, sorry for taking a while to get to this. I took a while to read this and while I am fairly confident that the logic hasn't changed much, I am not familiar enough with this part of the compiler to approve the change.

@rustbot reroll

TaKO8Ki · 2026-02-10T18:31:39Z

I have confirmed it does not change the current compiler behavior.

@bors r+ rollup=never

rust-bors · 2026-02-10T18:31:43Z

📌 Commit 892665b has been approved by TaKO8Ki

It is now in the queue for this repository.

rust-bors · 2026-02-11T00:57:58Z

☀️ Test successful - CI
Approved by: TaKO8Ki
Duration: 4h 6s
Pushing 7b25457 to main...

github-actions · 2026-02-11T01:00:32Z

What is this?

This is an experimental post-merge analysis report that shows differences in test outcomes between the merged PR and its parent PR.

Comparing 9e79395 (parent) -> 7b25457 (this PR)

Test differences

Show 2 test diffs

2 doctest diffs were found. These are ignored, as they are noisy.

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard 7b25457166468840db16998f507296675f0e07a0 --output-dir test-dashboard

And then open test-dashboard/index.html in your browser to see an overview of all executed tests.

Job duration changes

dist-x86_64-apple: 3h 40m -> 2h 17m (-37.6%)
dist-aarch64-llvm-mingw: 1h 37m -> 1h 55m (+19.3%)
x86_64-gnu-debug: 1h 55m -> 2h 6m (+10.2%)
x86_64-mingw-1: 2h 56m -> 2h 39m (-9.3%)
dist-x86_64-illumos: 1h 48m -> 1h 39m (-8.5%)
x86_64-msvc-1: 2h 38m -> 2h 25m (-8.1%)
i686-msvc-1: 3h 3m -> 2h 48m (-8.1%)
x86_64-msvc-2: 2h 33m -> 2h 21m (-7.9%)
aarch64-gnu-llvm-20-2: 49m 19s -> 52m 49s (+7.1%)
dist-aarch64-msvc: 1h 39m -> 1h 32m (-7.0%)

How to interpret the job duration changes?

Job durations can vary a lot, based on the actual runner instance
that executed the job, system noise, invalidated caches, etc. The table above is provided
mostly for t-infra members, for simpler debugging of potential CI slow-downs.

rust-timer · 2026-02-11T01:39:37Z

Finished benchmarking commit (7b25457): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

This benchmark run did not return any relevant results for this metric.

Cycles

This benchmark run did not return any relevant results for this metric.

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 476.965s -> 476.905s (-0.01%)
Artifact size: 398.02 MiB -> 398.04 MiB (0.01%)

rustbot assigned tiif Feb 1, 2026

petrochenkov reviewed Feb 2, 2026

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Zalathar force-pushed the cache-on-disk branch from b2d5760 to 6b38801 Compare February 3, 2026 01:16

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Zalathar force-pushed the cache-on-disk branch 2 times, most recently from 3820de3 to d24c1a0 Compare February 3, 2026 01:26

Zoxc reviewed Feb 3, 2026

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Zalathar mentioned this pull request Feb 4, 2026

Move the query list into a new rustc_middle::queries module #151893

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Zalathar force-pushed the cache-on-disk branch from d24c1a0 to c59d7f4 Compare February 4, 2026 12:41

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Clean up query macros for cache_on_disk_if

892665b

Zalathar force-pushed the cache-on-disk branch from c59d7f4 to 892665b Compare February 5, 2026 05:46

rustbot assigned TaKO8Ki and unassigned tiif Feb 8, 2026

rust-bors bot 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 Feb 10, 2026

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rust-bors bot added merged-by-bors This PR was explicitly merged by bors. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Feb 11, 2026

rust-bors bot merged commit 7b25457 into rust-lang:main Feb 11, 2026
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rustbot added this to the 1.95.0 milestone Feb 11, 2026

Zalathar deleted the cache-on-disk branch February 11, 2026 00:58

This was referenced Feb 11, 2026

Clarify names of QueryVTable functions for "executing" a query #152434

Open

Rework rustc_query_impl::define_queries. #152459

Open

Change query proc macro to be more rust-analyzer friendly #152422

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Clean up query macros for cache_on_disk_if #151943

Clean up query macros for cache_on_disk_if #151943

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TaKO8Ki commented Feb 10, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Test differences

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rust-timer commented Feb 11, 2026

Overall result: no relevant changes - no action needed

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Clean up query macros for `cache_on_disk_if` #151943

Clean up query macros for `cache_on_disk_if` #151943

TaKO8Ki commented Feb 10, 2026 •

edited

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