Remove `impl QueryVTable` by nnethercote · Pull Request #153323 · rust-lang/rust

nnethercote · 2026-03-03T03:30:17Z

Some simplifications to QueryVTable, partly extracted from #153065.

rustbot · 2026-03-03T03:30:22Z

Zalathar is not on the review rotation at the moment.
They may take a while to respond.

nnethercote · 2026-03-03T03:31:16Z

@Zalathar: as mentioned elsewhere, this partly undoes #151736. Not sure if you'll be accept it, but at least I won't die wondering.

Zalathar · 2026-03-03T03:55:58Z

I'm personally a little sad to see the options removed, but it's true that we currently aren't making any particular use of them (unlike hash_value_fn), so if perf is fine then it's hard for me to argue for keeping them as things currently stand.

I guess if I ever find a specific use case for wanting to know whether a query vtable ever caches to disk, I can always reintroduce a way to check that.

Zalathar · 2026-03-03T04:08:25Z

I think we already found no perf effects in #153065 (comment), but it's easy enough to double-check.

@bors try @rust-timer queue

Remove `impl QueryVTable`

nnethercote · 2026-03-03T04:23:19Z

BTW this will conflict with #153326 but I'm happy for that PR to land first.

rust-bors · 2026-03-03T06:18:20Z

☀️ Try build successful (CI)
Build commit: 0528e08 (0528e08a4da0a20fed6155ee91715eed54bee2fd, parent: ec818fda361ca216eb186f5cf45131bd9c776bb4)

rust-timer · 2026-03-03T07:13:39Z

Finished benchmarking commit (0528e08): comparison URL.

Overall result: ✅ improvements - no action needed

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

@bors rollup=never
@rustbot label: -S-waiting-on-perf -perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.3%	[-0.3%, -0.3%]	1
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (secondary -2.8%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.8%	[-2.8%, -2.8%]	1
All ❌✅ (primary)	-	-	0

Cycles

Results (secondary 3.1%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	3.1%	[3.1%, 3.1%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 480.002s -> 481.596s (0.33%)
Artifact size: 394.97 MiB -> 394.98 MiB (0.00%)

nnethercote · 2026-03-03T07:54:44Z

@bors rollup

nnethercote · 2026-03-04T07:16:26Z

BTW this will conflict with #153326 but I'm happy for that PR to land first.

That PR has landed and I have rebased. Ready for review.

rustbot · 2026-03-04T07:16:29Z

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.

Zalathar · 2026-03-04T07:43:30Z

r=me after considering the nit.

There are three query vtable functions related to the `cache_on_disk_if` modifier: - `will_cache_on_disk_for_key_fn` - `try_load_from_disk_fn` - `is_loadable_from_disk_fn` These are all function ptrs within an `Option`. They each have a wrapper that returns `false`/`None` if the function ptr is missing. This commit removes the `Option` wrappers. In the `None` case we now set the function ptr to a trivial closure that returns `false`/`None`. The commit also removes some typedefs that each have a single use. All this is a bit simpler, with less indirection. Note that `QueryVTable::hash_value_fn` is still an `Option`. Unlike the above three functions, which have trivial behaviour in the `None` case, `hash_value_fn` is used in ways where the `Some`/`None` distinction is more meaningful.

It's just a wrapper for `DepNode::construct` and it only has three uses. Better to just have one way of doing things.

nnethercote · 2026-03-04T19:32:34Z

@bors r=Zalathar rollup

rust-bors · 2026-03-04T19:32:38Z

📌 Commit d08f97d has been approved by Zalathar

It is now in the queue for this repository.

…uwer Rollup of 8 pull requests Successful merges: - #153361 (enable `PassMode::Indirect { on_stack: true, .. }` tail call arguments) - #153369 (library/test: always enable unstable features for miri) - #152283 (Properly pass offload sizes to kernel args) - #153323 (Remove `impl QueryVTable`) - #153385 (Fix comment on `is_horizontal_whitespace`) - #153394 (fix(thir): Include `NoneWithError` in Enum Struct Tail Assertion) - #153419 (rustc_llvm: add missing `-` to flag-comparison logic) - #153423 (Update dispatch2 to v0.3.1)

@Zalathar

Rollup merge of #153323 - nnethercote:rm-impl-QueryVTable, r=Zalathar Remove `impl QueryVTable` Some simplifications to `QueryVTable`, partly extracted from #153065. r? @Zalathar

rustbot assigned Zalathar Mar 3, 2026

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rust-borsBot pushed a commit that referenced this pull request Mar 3, 2026
Auto merge of#153323- nnethercote:rm-impl-QueryVTable, r=<try>
0528e08
Remove `impl QueryVTable`

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Mar 3, 2026

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nnethercote force-pushed the rm-impl-QueryVTable branch from a8af604 to 72c092cCompare March 4, 2026 07:16

Zalathar reviewed Mar 4, 2026
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Comment threadcompiler/rustc_middle/src/query/plumbing.rs Outdated

nnethercote added 2 commits March 4, 2026 20:57

Remove QueryVTable::construct_dep_node.
d08f97d
It's just a wrapper for `DepNode::construct` and it only has three uses. Better to just have one way of doing things.

nnethercote force-pushed the rm-impl-QueryVTable branch from 72c092c to d08f97dCompare March 4, 2026 19:31

rust-borsBot added the S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. label Mar 4, 2026

rust-borsBot removed the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Mar 4, 2026

JonathanBrouwer mentioned this pull request Mar 5, 2026
Rollup of 8 pull requests #153430
Merged

rust-borsBot merged commit 62d1a71 into rust-lang:mainMar 5, 2026
11 checks passed

rustbot added this to the 1.96.0 milestone Mar 5, 2026

rust-timer added a commit that referenced this pull request Mar 5, 2026
Unrolled build for#153323
0afe384
Rollup merge of #153323 - nnethercote:rm-impl-QueryVTable, r=Zalathar Remove `impl QueryVTable` Some simplifications to `QueryVTable`, partly extracted from #153065. r? @Zalathar

nnethercote deleted the rm-impl-QueryVTable branch March 5, 2026 19:50

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rust-timer commented Mar 3, 2026

Overall result: ✅ improvements - no action needed

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nnethercote commented Mar 3, 2026•
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