perf: use IndexVec for chunk TLA detection#8341
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Pull request overview
This PR optimizes the TLA (Top-Level Await) detection algorithm by replacing a FxHashMap-based approach with an IndexVec-based approach. This change improves performance by leveraging direct array indexing instead of hash lookups, which is more efficient when dealing with contiguous module indices.
Changes:
- Replaced
FxHashMap<ModuleIdx, Option<bool>>withIndexVec<ModuleIdx, TlaVisitState> - Introduced a
TlaVisitStateenum to represent visit states (NotVisited, Visiting, Visited) instead of usingOption<bool> - Refactored the
is_tlafunction to use pattern matching on the enum states
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hyf0
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Feb 16, 2026
Replaced `FxHashMap<ModuleIdx, Option<bool>>` with `IndexVec<ModuleIdx, TlaVisitState>` for less memory usage and less hash calculation.
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## [1.0.0-rc.5] - 2026-02-18
💡 Smarter `entriesAware` Manual Code Splitting
New `entriesAware` and `entriesAwareMergeThreshold` options for `manualCodeSplitting.groups[]` enable
entry-reachability-based chunk splitting with automatic small chunk merging.
- `entriesAware: true` splits matched modules by entry reachability — modules reached by the same set of entries are grouped together, providing the most precise loading behavior with less over-fetching
- Chunks now get more readable names reflecting their entry associations (e.g. `vendor-entry-a-entry-b.js`) instead of opaque hashes
- `entriesAwareMergeThreshold` sets a byte-size threshold to merge tiny subgroups into the closest sibling with the fewest extra entries, reducing micro-chunk fragmentation while preserving precision
- Recommended to use together with `maxSize`: merge tiny chunks first to reduce request overhead, then cap large chunks to control payload size
```js
manualCodeSplitting: {
groups: [{
name: 'vendor',
test: /node_modules/,
entriesAware: true,
entriesAwareMergeThreshold: 28000, // bytes
}]
}
```
### 🚀 Features
- add `Visitor` to `rolldown/utils` (#8373) by @sapphi-red
- module-info: add `inputFormat` property to `ModuleInfo` (#8329) by @shulaoda
- default `treeshake.invalid_import_side_effects` to `false` (#8357) by @sapphi-red
- rolldown_utils: add `IndexBitSet` (#8343) by @sapphi-red
- rolldown_utils: add more methods and trait impls to BitSet (#8342) by @sapphi-red
- rolldown_plugin_vite_build_import_analysis: add support for `await import().then((m) => m.prop)` (#8328) by @sapphi-red
- rolldown_plugin_vite_reporter: support custom logger for build infos (#7652) by @shulaoda
- rust/mcs: support `entriesAwareMergeThreshold` (#8312) by @hyf0
- mcs: `maxSize` will split the oversized chunk with taking file relevance into account (#8277) by @hyf0
- rolldown_plugin_vite_import_glob: support template literal in glob import patterns (#8298) by @shulaoda
- rolldown_plugin_chunk_import_map: output importmap without spaces (#8297) by @sapphi-red
- add INEFFECTIVE_DYNAMIC_IMPORT warning in core (#8284) by @shulaoda
- mcs: generate more readable name for `entriesAware` chunks (#8275) by @hyf0
- mcs: support `entriesAware` (#8274) by @hyf0
### 🐛 Bug Fixes
- improve circular dependency detection in chunk optimizer (#8371) by @IWANABETHATGUY
- align `minify.compress: true` and `minify.mangle: true` with `minify: true` (#8367) by @sapphi-red
- rolldown_plugin_esm_external_require: apply conversion to UMD and IIFE outputs (#8359) by @sapphi-red
- cjs: bailout treeshaking on cjs modules that have multiple re-exports (#8348) by @hyf0
- handle member expression and this expression in JSX element name rewriting (#8323) by @IWANABETHATGUY
- pad `encode_hash_with_base` output to fixed length to prevent slice panics (#8320) by @shulaoda
- `xxhash_with_base` skips hashing when input is exactly 16 bytes (#8319) by @shulaoda
- complete `ImportKind::try_from` with missing variants and correct `url-import` to `url-token` (#8310) by @shulaoda
- mark Node.js builtin modules as side-effect-free when resolved via `external` config (#8304) by @IWANABETHATGUY
- mcs: `maxSize` should split chunks correctly based on sizes (#8289) by @hyf0
### 🚜 Refactor
- introduce `RawMangleOptions` and `RawCompressOptions` (#8366) by @sapphi-red
- mcs: refactor `apply_manual_code_splitting` into `ManualSplitter` (#8346) by @hyf0
- rolldown_plugin_vite_reporter: simplify hook registration and remove redundant state (#8322) by @shulaoda
- use set to store user defined entry modules (#8315) by @IWANABETHATGUY
- rust/mcs: collect groups into map at first for having clean and performant operations (#8313) by @hyf0
- mcs: introduce newtype `ModuleGroupOrigin` and `ModuleGroupId` (#8311) by @hyf0
- remove unnecessary `FinalizerMutableState` struct (#8303) by @shulaoda
- move module finalization into `finalize_modules` (#8302) by @shulaoda
- extract `apply_transfer_parts_mutation` into its own module (#8301) by @shulaoda
- move ESM format check into `determine_export_mode` (#8294) by @shulaoda
- remove `warnings` field from `GenerateContext` (#8293) by @shulaoda
- extract util function remove clippy supression (#8290) by @IWANABETHATGUY
- move `is_in_node_modules` to `PathExt` trait in `rolldown_std_utils` (#8286) by @shulaoda
- rolldown_plugin_vite_reporter: remove unnecessary ineffective dynamic import detection logic (#8285) by @shulaoda
- dev: inject hmr runtime to `\0rolldown/runtime.js` (#8234) by @hyf0
- improve naming in chunk_optimizer (#8287) by @IWANABETHATGUY
- simplify PostChunkOptimizationOperation from bitflags to enum (#8283) by @IWANABETHATGUY
- optimize BitSet.index_of_one to return iterator instead of Vec (#8282) by @IWANABETHATGUY
### 📚 Documentation
- change default value in `format` JSDoc from `'esm'` to `'es'` (#8372) by @shulaoda
- in-depth: remove `invalidImportSideEffects` option mention from lazy barrel optimization doc (#8355) by @sapphi-red
- mcs: clarify `minSize` constraints (#8279) by @ShroXd
### ⚡ Performance
- use IndexVec for chunk TLA detection (#8341) by @sapphi-red
- only invoke single resolve call for the same specifier and import kind (#8332) by @sapphi-red
- rolldown_plugin_vite_reporter: skip gzip computation when `report_compressed_size` is disabled (#8321) by @shulaoda
### 🧪 Testing
- use `vi.waitFor` and `expect.poll` instead of custom `waitUtil` function (#8369) by @sapphi-red
- rolldown_plugin_esm_external_require_plugin: add tests (#8358) by @sapphi-red
- add watch file tests (#8330) by @sapphi-red
- rolldown_plugin_vite_build_import_analysis: add test for dynamic import treeshaking (#8327) by @sapphi-red
### ⚙️ Miscellaneous Tasks
- prepare-release: skip workflow on forked repositories (#8368) by @shulaoda
- format more files (#8360) by @sapphi-red
- deps: update oxc to v0.114.0 (#8347) by @camc314
- deps: update test262 submodule for tests (#8354) by @sapphi-red
- deps: update crate-ci/typos action to v1.43.5 (#8350) by @renovate[bot]
- deps: update oxc apps (#8351) by @renovate[bot]
- rolldown_plugin_vite_reporter: remove unnecessary README.md (#8334) by @shulaoda
- deps: update npm packages (#8338) by @renovate[bot]
- deps: update rust crates (#8339) by @renovate[bot]
- deps: update dependency oxlint-tsgolint to v0.13.0 (#8337) by @renovate[bot]
- deps: update github-actions (#8336) by @renovate[bot]
- deps: update napi to v3.8.3 (#8331) by @renovate[bot]
- deps: update dependency oxlint-tsgolint to v0.12.2 (#8325) by @renovate[bot]
- remove unnecessary transform.decorator (#8314) by @IWANABETHATGUY
- deps: update dependency rust to v1.93.1 (#8305) by @renovate[bot]
- deps: update dependency oxlint-tsgolint to v0.12.1 (#8300) by @renovate[bot]
- deps: update oxc apps (#8296) by @renovate[bot]
- docs: don't skip for build runs without cache (#8281) by @sapphi-red
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Replaced
FxHashMap<ModuleIdx, Option<bool>>withIndexVec<ModuleIdx, TlaVisitState>for less memory usage and less hash calculation.