fix: nullish coalescing operator precedence#240
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Boshen merged 1 commit intooxc-project:mainfrom Apr 1, 2023
ashsearle:fix/nullish-coalescing-precedence
Merged
fix: nullish coalescing operator precedence#240Boshen merged 1 commit intooxc-project:mainfrom ashsearle:fix/nullish-coalescing-precedence
Boshen merged 1 commit intooxc-project:mainfrom
ashsearle:fix/nullish-coalescing-precedence
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Neat! Did you find this from a real codebase? |
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Thank you for your first PR and trying out oxc! |
Boshen
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Replace multi-function calls and multiple enum variant checks with simple range checks, reducing assembly instructions in hot paths. ## Changes **`is_any_keyword()`**: - Before: Called 4 separate functions (`is_reserved_keyword()`, `is_contextual_keyword()`, `is_strict_mode_contextual_keyword()`, `is_future_reserved_keyword()`) checking 70+ enum variants with early returns - After: Single range check `Await..=Yield` since all keywords are contiguous in the enum **`is_number()`**: - Before: Matched 11 separate enum variants - After: Single range check `Decimal..=HexBigInt` since all numeric literals are contiguous ## Assembly Impact Multi-function approach generated **5 instructions** with complex bitmask setup: ```asm mov x8, #992 movk x8, #992, lsl #16 movk x8, #240, lsl #32 lsr x8, x8, x0 and w0, w8, #0x1 ``` Range check generates **4 instructions** with simple arithmetic: ```asm and w8, w0, #0xff sub w8, w8, #5 cmp w8, #39 cset w0, lo ``` ## Performance - `is_any_keyword()` is called from `advance()` on **every single token** - 20% fewer instructions (5 → 4) - Simpler logic enables better branch prediction - Eliminates complex constant loading Added tests to verify enum layout assumptions remain valid. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
Boshen
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Oct 7, 2025
Replace multi-function calls and multiple enum variant checks with simple range checks, reducing assembly instructions in hot paths. ## Changes **`is_any_keyword()`**: - Before: Called 4 separate functions (`is_reserved_keyword()`, `is_contextual_keyword()`, `is_strict_mode_contextual_keyword()`, `is_future_reserved_keyword()`) checking 70+ enum variants with early returns - After: Single range check `Await..=Yield` since all keywords are contiguous in the enum **`is_number()`**: - Before: Matched 11 separate enum variants - After: Single range check `Decimal..=HexBigInt` since all numeric literals are contiguous ## Assembly Impact Multi-function approach generated **5 instructions** with complex bitmask setup: ```asm mov x8, #992 movk x8, #992, lsl #16 movk x8, #240, lsl #32 lsr x8, x8, x0 and w0, w8, #0x1 ``` Range check generates **4 instructions** with simple arithmetic: ```asm and w8, w0, #0xff sub w8, w8, #5 cmp w8, #39 cset w0, lo ``` ## Performance - `is_any_keyword()` is called from `advance()` on **every single token** - 20% fewer instructions (5 → 4) - Simpler logic enables better branch prediction - Eliminates complex constant loading Added tests to verify enum layout assumptions remain valid. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
Boshen
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Oct 7, 2025
Replace multi-function calls and multiple enum variant checks with simple range checks, reducing assembly instructions in hot paths. ## Changes **`is_any_keyword()`**: - Before: Called 4 separate functions (`is_reserved_keyword()`, `is_contextual_keyword()`, `is_strict_mode_contextual_keyword()`, `is_future_reserved_keyword()`) checking 70+ enum variants with early returns - After: Single range check `Await..=Yield` since all keywords are contiguous in the enum **`is_number()`**: - Before: Matched 11 separate enum variants - After: Single range check `Decimal..=HexBigInt` since all numeric literals are contiguous ## Assembly Impact Multi-function approach generated **5 instructions** with complex bitmask setup: ```asm mov x8, #992 movk x8, #992, lsl #16 movk x8, #240, lsl #32 lsr x8, x8, x0 and w0, w8, #0x1 ``` Range check generates **4 instructions** with simple arithmetic: ```asm and w8, w0, #0xff sub w8, w8, #5 cmp w8, #39 cset w0, lo ``` ## Performance - `is_any_keyword()` is called from `advance()` on **every single token** - 20% fewer instructions (5 → 4) - Simpler logic enables better branch prediction - Eliminates complex constant loading Added tests to verify enum layout assumptions remain valid. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
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Oct 7, 2025
…14410) ## Summary Replace multi-function calls and multiple enum variant checks with simple range checks, reducing assembly instructions in hot paths. ## Changes ### `is_any_keyword()` **Before**: Called 4 separate functions checking 70+ enum variants: - `is_reserved_keyword()` - 38 variants - `is_contextual_keyword()` - 39 variants - `is_strict_mode_contextual_keyword()` - 8 variants - `is_future_reserved_keyword()` - 7 variants **After**: Single range check `Await..=Yield` since all keywords are contiguous in the enum ### `is_number()` **Before**: Matched 11 separate enum variants **After**: Single range check `Decimal..=HexBigInt` since numeric literals are contiguous ## Assembly Analysis ### Before (with scattered checks) ```asm mov x8, #992 ; Load bitmask constant movk x8, #992, lsl #16 ; More bitmask setup movk x8, #240, lsl #32 ; Even more bitmask setup lsr x8, x8, x0 ; Shift by kind value and w0, w8, #0x1 ; Extract result bit ``` **5 instructions** with complex constant loading ### After (with range check) ```asm and w8, w0, #0xff ; Extract byte sub w8, w8, #5 ; Subtract range start cmp w8, #39 ; Compare to range size cset w0, lo ; Set result ``` **4 instructions** with simple arithmetic ## Performance Impact - **20% fewer instructions** (5 → 4) - **Simpler logic** = better CPU pipeline utilization - **No complex constants** = smaller code size - **Better branch prediction** with single comparison This is particularly important because: - `is_any_keyword()` is called from `advance()` on **every single token** - This is one of the hottest code paths in the entire parser ## Testing Added unit tests to verify that: - All keywords remain contiguous in the enum (`Await..=Yield`) - All numeric literals remain contiguous (`Decimal..=HexBigInt`) These tests will catch any future enum reordering that would break the optimization. 🤖 Generated with [Claude Code](https://claude.com/claude-code)
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Fix one error copying operator precedence values from MDN's table
The mistake gave
inand??the same precedence. Add a test that should have failed (and with this PR it now does.)