perf(diagnostics): box OxcDiagnosticInner to reduce binary size by 4%#24656
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perf(diagnostics): box OxcDiagnosticInner to reduce binary size by 4%#24656Boshen wants to merge 1 commit into
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`OxcDiagnostic` is an unboxed ~304-byte struct constructed at thousands of callsites. Boxing its inner data behind an 8-byte handle shrinks the stripped `oxlint` release binary by ~549 KiB (-4.0%): oxc_linter -307 KiB, oxc_react_compiler -102 KiB, and others. This reverses #22406, which unboxed the inner to save a heap allocation. That is now safe: the parser no longer constructs diagnostics on its hot path (see the previous commit). Also drops the now-obsolete `large_enum_variant` expectation on `CliConfigLoadError`, whose `OxcDiagnostic` variant is now small.
Merging this PR will improve performance by 5.55%
|
| Mode | Benchmark | BASE |
HEAD |
Efficiency | |
|---|---|---|---|---|---|
| ⚡ | Simulation | react_compiler[RadixUIAdoptionSection.jsx] |
2.7 ms | 2.5 ms | +7.6% |
| ⚡ | Simulation | linter[react.development.js] |
13.6 ms | 12.7 ms | +7.37% |
| ⚡ | Simulation | linter[RadixUIAdoptionSection.jsx] |
3.2 ms | 3 ms | +7.21% |
| ⚡ | Simulation | linter[binder.ts] |
27 ms | 25.8 ms | +4.94% |
| ⚡ | Simulation | parser[RadixUIAdoptionSection.jsx] |
84.8 µs | 80.9 µs | +4.83% |
| ⚡ | Simulation | linter[App.tsx] |
67.7 ms | 65 ms | +4% |
| ⚡ | Simulation | transformer[react.development.js] |
705.5 µs | 684.9 µs | +3.01% |
Tip
Curious why this is faster? Comment @codspeedbot explain why this is faster on this PR, or directly use the CodSpeed MCP with your agent.
Comparing perf/box-oxc-diagnostic-inner (3975763) with perf/defer-parser-diagnostics (8ce3853)
Footnotes
-
9 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩
Boshen
marked this pull request as draft
July 19, 2026 06:21
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Jul 19, 2026
`OxcDiagnostic` is an unboxed ~300-byte struct constructed at thousands of callsites. Boxing its inner data behind an 8-byte handle means every callsite, every `Result<T, OxcDiagnostic>`, and every move copies 8 bytes instead of ~300, so the compiler emits far less inlined construction/copy code. ## Binary size (stripped, real release builds, aarch64-apple-darwin) | Binary | Before | After | Delta | |---|---:|---:|---:| | `oxlint` | 14,177,616 B | 13,665,680 B | **−499.9 KiB (−3.61%)** | | napi transform (`.node`) | 3,482,624 B | 3,433,040 B | **−48.4 KiB (−1.42%)** | Most of the win lands in `oxc_linter`, whose ~1,500 diagnostic-construction sites inline into rule bodies; `oxc_react_compiler` also contributes. The `error`/`warn` constructors delegate to an outlined `#[inline(never)] fn new`, so the `Box` allocation + field initialization exist once in the binary rather than inlined at every construction site. This reverses #22406, which unboxed the inner to save a heap allocation. That is now safe: the parser no longer constructs diagnostics on its hot path (#24663). Supersedes the draft #24656, which additionally carried a now-redundant copy of the parser deferral that has since landed via #24663.
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OxcDiagnosticis an unboxed ~304-byte struct constructed at thousands ofcallsites. Boxing its inner data behind an 8-byte handle shrinks the stripped
oxlintrelease binary by ~549 KiB (-4.0%): oxc_linter -307 KiB,oxc_react_compiler -102 KiB, and others.
This reverses #22406, which unboxed the inner to save a heap allocation. That is
now safe: the parser no longer constructs diagnostics on its hot path (see the
previous commit). Also drops the now-obsolete
large_enum_variantexpectationon
CliConfigLoadError, whoseOxcDiagnosticvariant is now small.Stack created with GitHub Stacks CLI • Give Feedback 💬