perf(estree/tokens): do not JSON-encode keyword, punctuator, etc tokens#19814
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Merging this PR will improve performance by 24.01%
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Pull request overview
Optimizes ESTree token JSON serialization by routing JSON-safe tokens (keywords, punctuators, numbers, booleans, null, and most identifiers) through a fast manual serializer, while keeping escape-checked serialization for token values that may contain JSON-unsafe bytes.
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- Introduces
EstreeSafeToken(manual JSON assembly) and renames the previous general token type toEstreeUnsafeToken. - Refactors token emission to default to the safe fast-path and adds visitors to ensure string/template/JSXText tokens are emitted via the unsafe path.
- Tightens invariants around which token kinds may reach
get_token_type(debug assertion) after splitting safe vs unsafe handling.
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…ns (#19814) After #19744, #19813, #19812, and #19796, all tokens which require special handling or can contain `value`s which are possibly not JSON-safe are handled separately. So everything remaining (keywords, punctuators etc) are JSON-safe and can be serialized via the optimized serializer introduced for identifiers in #19744. To reflect that `EstreeIdentToken` now handles a lot more than identifiers, rename it to `EstreeSafeToken`, and rename `EstreeToken` to `EstreeUnsafeToken`. Large positive perf impact. +24% on ESTree tokens benchmark.
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Remove the `regex` field from `EstreeToken` and serialize regex tokens via their own dedicated type `EstreeRegExpToken`. This removes a branch and logic from `emit_token` which is the path the processes all tokens except identifiers. This PR is actually showing as a small perf degradation (-1% on ESTree tokens benchmark). But it enables a much bigger optimization later on in #19814.
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After #19744, #19813, #19812, and #19796, all tokens which require special handling or can contain
values which are possibly not JSON-safe are handled separately. So everything remaining (keywords, punctuators etc) are JSON-safe and can be serialized via the optimized serializer introduced for identifiers in #19744.To reflect that
EstreeIdentTokennow handles a lot more than identifiers, rename it toEstreeSafeToken, and renameEstreeTokentoEstreeUnsafeToken.Large positive perf impact. +24% on ESTree tokens benchmark.