perf: cut two heap allocations from wrapped ESM init finalize#9901
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Been thinking a to have infra to track every stage's mem/cpu opts
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## What `wrapped_esm_init_stmt_for_import_record` (scope-hoisting finalize path) performed two heap allocations per wrapped-ESM import record. This removes both, with no behavior change. ### 1. Per-record `FxIndexSet` → `Vec` `collect_wrapped_esm_init_modules_for_import_record` returned an owned `FxIndexSet<ModuleIdx>` only to dedup owners within a single record. Its sole caller already filters every owner through the persistent `generated_init_esm_importee_ids` (`FxHashSet`) **before** building the init call, so the local set's dedup is fully subsumed by the global one — a duplicate is dropped at the global check and never re-emits. Switching to `Vec<ModuleIdx>` replaces the IndexMap insert/rehash with a plain push and drops one hashmap allocation per record. ### 2. Drop the `.collect::<Vec<_>>()` of init expressions The expressions were collected into a `std::Vec` only to end the `&mut self` iterator borrow before reaching for `self.ast_factory`. `AstFactory` is `Copy`, so copying it out lets the iterator stay borrowed while nodes are still built through the copy. Driving the iterator by hand means the common 0- and 1-statement cases allocate nothing, and only the rare `(a(), b())` sequence case allocates — straight into the arena. Every branch consumes the iterator to exhaustion, preserving the global-dedup side effects exactly. ## Evidence `cargo asm -p rolldown --lib wrapped_esm_init_stmt` (aarch64, release `lto = "fat"`): | | before | after | |---|---|---| | instructions | 808 | **731** | | calls (`bl`) | 40 | **27** | Removed calls include `indexmap::IndexMap::insert_full`, `drop_in_place<IndexSet<ModuleIdx>>`, and the std `Vec`'s `__rust_alloc` / `RawVecInner::reserve` / `__rust_dealloc`. The remaining `hashbrown` calls are the global `generated_init_esm_importee_ids` dedup, which is intentionally kept. ## Verification `cargo test -p rolldown` — 1756 passed, 0 failed; all snapshots unchanged (byte-identical output).
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## [1.1.3] - 2026-06-24 ### 🐛 Bug Fixes - `defer_drop` crashes the browser main thread (#9942) by @shulaoda - camel-case: correct camel case for nested values (#9933) by @kb019 - cli: display --help options in camelCase (#9941) by @IWANABETHATGUY - preserve used re-exports under preserveModules (#9122) (#9934) by @IWANABETHATGUY - watch: make close reentrant in event callbacks (#9904) by @hyf0 - git for windows treats symlink files as regular files (#9915) by @AliceLanniste - dev: cancel pending full reload on build error (#9903) by @h-a-n-a - chunking: pass plugin meta to codeSplitting groups name function (#9267) by @Kyujenius - dev: serve assets emitted during HMR/lazy compile (vite#22596) (#9815) by @h-a-n-a - release: dry-run step no longer publishes binding packages (#9866) by @Boshen ### 🚜 Refactor - rolldown_common: model ModuleId as a classified Path/Virtual/Bare enum (#9927) by @Boshen - remove unused LegacyModuleIdx (#9872) by @shulaoda - remove unused StmtInfos::get_namespace_stmt_info (#9870) by @shulaoda - remove unused Module::as_external_mut (#9871) by @shulaoda - remove unused EcmaAst::is_body_empty (#9869) by @shulaoda - drop dead is_css_module handling in resolve_dependencies (#9867) by @shulaoda - drop redundant with_commonjs on cjs source type (#9868) by @shulaoda ### 📚 Documentation - clarify on drafting PRs (#9952) by @h-a-n-a - update contribution guidelines (#9944) by @fubhy - note Rust crates don't follow semver in AGENTS.md (#9905) by @IWANABETHATGUY - add feedback form (#9159) by @TheAlexLichter ### ⚡ Performance - utils: avoid allocation in default_sanitize_file_name for clean names (#9928) by @Boshen - binding: box once-per-build futures before spawn_future (#9864) by @Boshen - utils: avoid wasted allocation in legitimize_identifier_name (#9926) by @Boshen - rolldown: fuse the canonical-name dedup and insert in the renamer (#9900) by @Boshen - rolldown: probe the name map once in ConflictResolver::resolve (#9899) by @Boshen - cut two heap allocations from wrapped ESM init finalize (#9901) by @Boshen - rolldown_plugin_vite_reporter: hoist invariant out_dir prefix out of reporter loop (#9873) by @shulaoda - drop throwaway Vec in wrapped esm init stmt (#9878) by @shulaoda - borrow owner_filename in build-import-analysis AddDeps (#9874) by @shulaoda ### 🧪 Testing - cover preserveModules named export via namespace re-export (#6010) (#9937) by @IWANABETHATGUY ### ⚙️ Miscellaneous Tasks - deps: update napi to v3.9.4 (#9954) by @shulaoda - reduce noise from CODEOWNERS for trival changes (#9953) by @h-a-n-a - deps: update mimalloc-safe to 0.1.64 (#9950) by @shulaoda - deps: update rollup submodule for tests to v4.62.2 (#9931) by @rolldown-guard[bot] - deps: test mimalloc-safe upstream-mimalloc switch in CI (#9930) by @shulaoda - rolldown_plugin_vite_build_import_analysis: remove unused v2 code path (#9917) by @shulaoda - rolldown_plugin_vite_manifest: remove unused is_enable_v2 code path (#9916) by @shulaoda - rolldown_plugin_vite_asset_import_meta_url: remove unexposed native vite plugin (#9896) by @shulaoda - rolldown_plugin_vite_asset: remove unexposed native vite plugin (#9895) by @shulaoda - rolldown_plugin_vite_css_post: remove unexposed native vite plugin (#9894) by @shulaoda - rolldown_plugin_vite_css: remove unexposed native vite plugin (#9893) by @shulaoda - rolldown_plugin_vite_html_inline_proxy: remove unexposed native vite plugin (#9892) by @shulaoda - rolldown_plugin_vite_html: remove unexposed native vite plugin (#9891) by @shulaoda - deps: update github actions (#9909) by @renovate[bot] - deps: update rust crate oxc_sourcemap to v8.0.2 (#9910) by @renovate[bot] - deps: update npm packages (#9912) by @renovate[bot] - deps: update github actions to v7 (#9913) by @renovate[bot] - deps: update rolldown-plugin-dts to ^0.26.0 (#9897) by @renovate[bot] - remove rolldown_filter_analyzer crate (#9865) by @Boshen ### ❤️ New Contributors * @fubhy made their first contribution in [#9944](#9944) Co-authored-by: shulaoda <165626830+shulaoda@users.noreply.github.com>
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What
wrapped_esm_init_stmt_for_import_record(scope-hoisting finalize path) performed two heap allocations per wrapped-ESM import record. This removes both, with no behavior change.1. Per-record
FxIndexSet→Veccollect_wrapped_esm_init_modules_for_import_recordreturned an ownedFxIndexSet<ModuleIdx>only to dedup owners within a single record. Its sole caller already filters every owner through the persistentgenerated_init_esm_importee_ids(FxHashSet) before building the init call, so the local set's dedup is fully subsumed by the global one — a duplicate is dropped at the global check and never re-emits. Switching toVec<ModuleIdx>replaces the IndexMap insert/rehash with a plain push and drops one hashmap allocation per record.2. Drop the
.collect::<Vec<_>>()of init expressionsThe expressions were collected into a
std::Veconly to end the&mut selfiterator borrow before reaching forself.ast_factory.AstFactoryisCopy, so copying it out lets the iterator stay borrowed while nodes are still built through the copy. Driving the iterator by hand means the common 0- and 1-statement cases allocate nothing, and only the rare(a(), b())sequence case allocates — straight into the arena. Every branch consumes the iterator to exhaustion, preserving the global-dedup side effects exactly.Evidence
cargo asm -p rolldown --lib wrapped_esm_init_stmt(aarch64, releaselto = "fat"):bl)Removed calls include
indexmap::IndexMap::insert_full,drop_in_place<IndexSet<ModuleIdx>>, and the stdVec's__rust_alloc/RawVecInner::reserve/__rust_dealloc. The remaininghashbrowncalls are the globalgenerated_init_esm_importee_idsdedup, which is intentionally kept.Verification
cargo test -p rolldown— 1756 passed, 0 failed; all snapshots unchanged (byte-identical output).