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perf(linter/plugins): pre-populate cache of EnterExit objects at startup#20194

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Mar 10, 2026
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perf(linter/plugins): pre-populate cache of EnterExit objects at startup#20194
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om/03-10-perf_linter_plugins_pre-populate_cache_of_enterexit_objects_at_startup

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@overlookmotel overlookmotel commented Mar 10, 2026

Perf optimization to visitor compilation. Continuation of #20187.

Instead of populating the cache of EnterExit objects in finalizeCompiledVisitor, populate it in full at process startup.

The main gain is that it makes these objects, which are heavily accessed during AST walk, more likely to be grouped together in memory, reducing L1 cache misses, and consuming less L1 cache.

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@github-actions github-actions bot added A-linter Area - Linter A-cli Area - CLI A-linter-plugins Area - Linter JS plugins C-performance Category - Solution not expected to change functional behavior, only performance labels Mar 10, 2026
@overlookmotel overlookmotel marked this pull request as ready for review March 10, 2026 13:14
@overlookmotel overlookmotel requested a review from camc314 as a code owner March 10, 2026 13:14
Copilot AI review requested due to automatic review settings March 10, 2026 13:14
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Pull request overview

This PR is a performance optimization for the visitor compilation phase in the JS plugin system. Instead of lazily growing the EnterExit object cache in finalizeCompiledVisitor on each file, all EnterExit objects (one per non-leaf AST node type) are allocated together at module startup. This improves memory locality by ensuring the objects — which are heavily accessed during AST traversal — are allocated contiguously and are more likely to be grouped together when V8 promotes them from "new space" to "old space", reducing L1 cache misses. This continues the performance work started in PR #20187.

Changes:

  • Pre-populate enterExitObjectCache with all needed EnterExit objects at module startup (matching NON_LEAF_NODE_TYPES_COUNT).
  • Remove the now-redundant while loop from finalizeCompiledVisitor that was previously needed to ensure cache capacity.
  • Remove the now-redundant debugAssert from resetCompiledVisitor that guarded cache size, and remove the corresponding pre-condition requirement from its JSDoc.

@overlookmotel overlookmotel added the 0-merge Merge with Graphite Merge Queue label Mar 10, 2026
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overlookmotel commented Mar 10, 2026

Merge activity

…artup (#20194)

Perf optimization to visitor compilation. Continuation of #20187.

Instead of populating the cache of `EnterExit` objects in `finalizeCompiledVisitor`, populate it in full at process startup.

The main gain is that it makes these objects, which are heavily accessed during AST walk, more likely to be grouped together in memory, reducing L1 cache misses, and consuming less L1 cache.
@graphite-app graphite-app bot force-pushed the om/03-10-perf_linter_plugins_pre-populate_cache_of_enterexit_objects_at_startup branch from b877e63 to 3a86427 Compare March 10, 2026 13:29
@graphite-app graphite-app bot merged commit 3a86427 into main Mar 10, 2026
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@graphite-app graphite-app bot deleted the om/03-10-perf_linter_plugins_pre-populate_cache_of_enterexit_objects_at_startup branch March 10, 2026 13:41
@graphite-app graphite-app bot removed the 0-merge Merge with Graphite Merge Queue label Mar 10, 2026
leaysgur added a commit that referenced this pull request Mar 11, 2026
# Oxlint
### 🚀 Features

- 04a5ce0 oxlint: Support `vite.config.ts` `.lint` field (#20214)
(leaysgur)
- 1735215 linter: Implement `react/no-clone-element` rule. (#20129)
(connorshea)
- 68e6f6f linter: Implement `react/no-react-children` rule. (#20104)
(connorshea)
- fe3b32e linter/plugins: Add `oxlint-plugin-eslint` package (#20009)
(overlookmotel)

### 🐛 Bug Fixes

- 05f6a09 linter/no-inline-comments: Deserialize rule options with serde
(#20207) (camc314)
- c7eb09d linter/default-case: Deserialize rule options with serde
(#20206) (camc314)
- f85e16c linter/plugins: Fix types for visitor compilation (#20203)
(overlookmotel)
- 44e24e0 linter/exhaustive-deps: Ignore type-only typeof deps (#20201)
(camc314)
- 0b04998 linter/no-fallthrough: Deserialize rule options with serde
(#20192) (camc314)
- a1031cb linter/new-cap: Deserialize rule options with serde (#20161)
(camc314)
- ad27fd6 linter: Add help messages to import plugin diagnostics
(#20158) (John Costa)
- 1340307 linter/plugins: Ensure `after` hooks always run (#20167)
(overlookmotel)
- c4812ec linter/plugins: Reset visitor compilation state if error
during compilation (#20166) (overlookmotel)
- 887eecc linter/plugins: Add license notice to `oxlint-plugin-eslint`
package (#20164) (overlookmotel)
- e1713a4 linter/plugins: Include common chunks in
`oxlint-plugin-eslint` package (#20163) (overlookmotel)
- a9acb2b linter: Check `globals` entry for `no-undef`, only check
es2026 globals for `no-extend-native` and
`no-constant-binary-expression` (#20089) (Sysix)
- 5559f0d linter/no-unused-vars: `reportUsedIgnorePattern` should not
report used rest siblings (#20108) (Don Isaac)
- de7c0e2 linter/plugins: Correct error message for `markVariableAsUsed`
(#20152) (overlookmotel)

### ⚡ Performance

- 3a86427 linter/plugins: Pre-populate cache of `EnterExit` objects at
startup (#20194) (overlookmotel)
- d243391 linter/plugins: Replace arrays with `Uint8Array`s (#20190)
(overlookmotel)
- 8742f8b linter/plugins: Pre-populate cache of `VisitProp` objects
(#20189) (overlookmotel)
- 3061acb linter/plugins: Pre-populate cache of `EnterExit` objects
(#20187) (overlookmotel)
- c73912b linter/plugins: Free visit functions earlier (#20186)
(overlookmotel)
- d9f8ff4 linter/plugins: Faster reset of visitor state (#20185)
(overlookmotel)
- 42aff15 oxlint/lsp: Avoid computing diagnostics for non invoked code
actions requests (#20080) (Sysix)

### 📚 Documentation

- a080650 linter/plugins: Fix documentation of visitor compilation
(#20202) (overlookmotel)
- 542a04a linter: Add a link to the cyclomatic complexity Wikipedia
article in `eslint/complexity` (#20174) (connorshea)
# Oxfmt
### 🚀 Features

- 95943aa oxfmt: Support `vite.config.*` `.fmt` field (#20197)
(leaysgur)
- 172fc07 oxfmt: .js/.ts config file support (#20135) (leaysgur)

### 🐛 Bug Fixes

- e483569 oxfmt: Avoid double-escaping in css-in-js (#20211) (leaysgur)

Co-authored-by: leaysgur <6259812+leaysgur@users.noreply.github.com>
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