perf(codegen): remove bounds check from SourcemapBuilder#19578
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Pull request overview
This PR applies a small performance-oriented tweak to SourcemapBuilder::update_generated_line_and_column by reducing bounds checks when detecting Unicode line separators (U+2028/U+2029) in the generated output, and adds clarifying comments about intentionally not adding additional work to the hot loop for uncommon Unicode cases.
Changes:
- Replace two direct index reads (
output[idx + 1],output[idx + 2]) with a single slice-rangegetto fetch/compare the next two bytes. - Add comments explaining why the loop increments
idxby 1 for non-ASCII bytes instead of attempting to skip full UTF-8 sequences.
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Follow-on after #19548. Remove a bounds check from hot loop in `SourcemapBuilder::update_generated_line_and_column` by doing only 1 bounds check to get next 2 bytes, instead of 2 bounds checks for each byte. This optimization was taken from @cam314's original version of PR #19548. While reviewing that PR I also thought I'd spied 2 other optimizations, but on reflection, I realized they were better left as is. Add comments to explain why.
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### 🚀 Features - e814049 oxc_data_structure/rope: Add `get_offset_from_line_and_column` (#18133) (Sysix) ### 🐛 Bug Fixes - 7958b56 linter: Fix syntax error reporting in some output formatters. (#19590) (connorshea) - e316694 codegen: Avoid sourcemap panic on `U+2028`/`U+2029` (#19548) (camc314) - 933ff72 semantic: Emit correct error code for reserved type name (#19545) (camc314) ### ⚡ Performance - b5fa195 codegen: Remove bounds check from `SourcemapBuilder` (#19578) (overlookmotel) Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com>
Follow-on after #19548.
Remove a bounds check from hot loop in
SourcemapBuilder::update_generated_line_and_columnby doing only 1 bounds check to get next 2 bytes, instead of 2 bounds checks for each byte.This optimization was taken from @cam314's original version of PR #19548.
While reviewing that PR I also thought I'd spied 2 other optimizations, but on reflection, I realized they were better left as is. Add comments to explain why.