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The lexer previously used its own internal `LexerCtx` abstraction that allowed it to consume the characters that made up a token without changing the lexer state, then update the state at once when committing to consuming the characters. However, manually resetting the lexer to the original position when giving up on parsing a token is simple enough that this abstraction was not holding its weight. Simplify the lexer by removing internal contexts, and move the simplified method bodies to lexer.h. Generally we try to avoid putting lots of code in headers, but in this case making the code available to the inliner, along with removing the extra layer of abstraction, makes the parser about 20% faster.
tlively
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Apr 14, 2026
The first parser pass is responsible for two things: finding the locations of definitions of top-level module items like globals and functions and finding the locations of implicit function type definitions. It previously accomplished the latter by fully parsing every instruction in each function. But the IR is not constructed in this phase of parsing, so fully parsing every instruction was largely wasted work. Optimize the parser by parsing only the instructions that might have implicit type definitions and otherwise just blindly match parentheses to skip the function body. Combined with #8597, this speeds up parsing by 30-40%.
kripken
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Do I want to know how this affects our compile times? 😄
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No difference! (at least on a very unscientific experiment with N=1) |
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The lexer previously used its own internal
LexerCtxabstraction that allowed it to consume the characters that made up a token without changing the lexer state, then update the state at once when committing to consuming the characters. However, manually resetting the lexer to the original position when giving up on parsing a token is simple enough that this abstraction was not holding its weight. Simplify the lexer by removing internal contexts, and move the simplified method bodies to lexer.h. Generally we try to avoid putting lots of code in headers, but in this case making the code available to the inliner, along with removing the extra layer of abstraction, makes the parser about 20% faster.