perf: More efficient computation of used symbols#4568
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WillLillis merged 1 commit intotree-sitter:masterfrom Jul 10, 2025
Merged
perf: More efficient computation of used symbols#4568WillLillis merged 1 commit intotree-sitter:masterfrom
WillLillis merged 1 commit intotree-sitter:masterfrom
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As the call to `symbol_is_used` does not depend on the production, it is more efficient to call it only once outside the loop over productions. I'm not sure if `rustc` is able to do this optimization on its own (it would need to know that the function is pure, which sounds difficult in general).
WillLillis
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Jul 8, 2025
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As the call to
symbol_is_useddoes not depend on the production, it is more efficient to call it only once outside the loop over productions.More broadly, the reachable symbols are currently computed at three stages of parser generation (listed here from upstream to downstream):
parse_grammar.rs, where I added the warning in feat: Warn about unreachable variables #4567)flatten_grammar.rs)build_tables.rs)I'm not clear on whether all those stages are useful - can the reachability of some symbols change because of some intermediate transformations?