From 82a7db401ccd1a33de82c388ecf72be905621f05 Mon Sep 17 00:00:00 2001
From: overlookmotel <557937+overlookmotel@users.noreply.github.com>
Date: Sun, 1 Nov 2026 21:38:51 +0000
Subject: [PATCH] refactor(lexer): compile `find_line_terminator` separately
 for each CPU feature set (#28618)

Part of effort to move to runtime CPU feature detection.

Apply `cpu_versions!` to `find_line_terminator`, keeping its `#[inline]` attribute. It doesn't use `cpu` yet. `carve_js`, `carve_jsx` and `jsx_skip_trivia` pass it `cpu`. The cold `lex_html_open_comment` and `lex_html_close_comment` are compiled only once, so they pass `BASELINE`.

No change to codegen.
---
 crates/oxc_lexer/src/pipeline/carve/comments.rs  |  4 ++--
 crates/oxc_lexer/src/pipeline/carve/common.rs    | 10 ++++++++--
 crates/oxc_lexer/src/pipeline/carve/js.rs        |  2 +-
 crates/oxc_lexer/src/pipeline/carve/jsx/mod.rs   |  2 +-
 crates/oxc_lexer/src/pipeline/carve/jsx/names.rs |  4 ++--
 5 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/crates/oxc_lexer/src/pipeline/carve/comments.rs b/crates/oxc_lexer/src/pipeline/carve/comments.rs
index 775c11667d..69b4f5d06d 100644
--- a/crates/oxc_lexer/src/pipeline/carve/comments.rs
+++ b/crates/oxc_lexer/src/pipeline/carve/comments.rs
@@ -142,7 +142,7 @@ pub(super) unsafe fn lex_html_open_comment(
     if lanes.module {
         lanes.push_diag(s as u32, 4, DiagCode::HtmlCommentInModule);
     }
-    let end = find_line_terminator(src, n, s + 4);
+    let end = find_line_terminator(src, n, s + 4, cpu);
     *kind.add(s) = tk!(LineComment);
     if end > s + 1 {
         bm_clear_range(st, s + 1, end - 1);
@@ -193,7 +193,7 @@ pub(super) unsafe fn lex_html_close_comment(
     let cpu = BASELINE;
 
     let start = s - 2;
-    let end = find_line_terminator(src, n, s + 1);
+    let end = find_line_terminator(src, n, s + 1, cpu);
     *kind.add(start) = tk!(LineComment);
     bm_set(st, start);
     if end > start + 1 {
diff --git a/crates/oxc_lexer/src/pipeline/carve/common.rs b/crates/oxc_lexer/src/pipeline/carve/common.rs
index 4f75c2b05f..974f9a7963 100644
--- a/crates/oxc_lexer/src/pipeline/carve/common.rs
+++ b/crates/oxc_lexer/src/pipeline/carve/common.rs
@@ -3,7 +3,7 @@ use crate::{error::DiagCode, token::tk};
 use crate::pipeline::{
     bitmap::{bm_clear, bm_clear_range, bm_get, bm_next0},
     bytes::hex_val,
-    cpu::Cpu,
+    cpu::{Cpu, apply, cpu_versions},
     disambiguate::not_operator_position,
     find::find,
     lanes::Lanes,
@@ -192,8 +192,14 @@ pub(super) unsafe fn skip_unicode_brace_escape(src: *const u8, n: usize, s: usiz
 /// (U+2028/U+2029). Stops at LS/PS too, so the hashbang scan cannot run
 /// through one. A 0xE2 that isn't LS/PS keeps scanning; the 2-byte confirm
 /// past a trailing 0xE2 reads the pad, which can never match 0x80.
+#[apply(cpu_versions)]
 #[inline]
-pub(super) unsafe fn find_line_terminator(src: *const u8, n: usize, mut i: usize) -> usize {
+pub(super) unsafe fn find_line_terminator(
+    src: *const u8,
+    n: usize,
+    mut i: usize,
+    _cpu: impl Cpu,
+) -> usize {
     loop {
         let p = find(src, n, i, [b'\n', b'\r', 0xE2]);
         if p >= n {
diff --git a/crates/oxc_lexer/src/pipeline/carve/js.rs b/crates/oxc_lexer/src/pipeline/carve/js.rs
index abd2bb5e3f..9f23a40e61 100644
--- a/crates/oxc_lexer/src/pipeline/carve/js.rs
+++ b/crates/oxc_lexer/src/pipeline/carve/js.rs
@@ -33,7 +33,7 @@ pub(super) unsafe fn carve_js(
     let mut depth: Vec<u32> = Vec::with_capacity(64);
     let mut i = 0usize;
     if n >= 2 && *src == b'#' && *src.add(1) == b'!' {
-        let end = find_line_terminator(src, n, 2);
+        let end = find_line_terminator(src, n, 2, cpu);
         *kind = tk!(Hashbang);
         bm_clear_range(st, 1, end - 1);
         if end < n {
diff --git a/crates/oxc_lexer/src/pipeline/carve/jsx/mod.rs b/crates/oxc_lexer/src/pipeline/carve/jsx/mod.rs
index b1900513c4..7a278f1e72 100644
--- a/crates/oxc_lexer/src/pipeline/carve/jsx/mod.rs
+++ b/crates/oxc_lexer/src/pipeline/carve/jsx/mod.rs
@@ -104,7 +104,7 @@ pub(super) unsafe fn carve_jsx(
     let mut text_start = 0usize;
     let mut i = 0usize;
     if n >= 2 && *src == b'#' && *src.add(1) == b'!' {
-        let end = find_line_terminator(src, n, 2);
+        let end = find_line_terminator(src, n, 2, cpu);
         *kind = tk!(Hashbang);
         bm_clear_range(st, 1, end - 1);
         if end < n {
diff --git a/crates/oxc_lexer/src/pipeline/carve/jsx/names.rs b/crates/oxc_lexer/src/pipeline/carve/jsx/names.rs
index 05d36e7df6..a96eaf0604 100644
--- a/crates/oxc_lexer/src/pipeline/carve/jsx/names.rs
+++ b/crates/oxc_lexer/src/pipeline/carve/jsx/names.rs
@@ -78,7 +78,7 @@ pub(super) unsafe fn jsx_skip_trivia(
     src: *const u8,
     n: usize,
     mut i: usize,
-    _cpu: impl Cpu,
+    cpu: impl Cpu,
 ) -> usize {
     loop {
         if i >= n {
@@ -100,7 +100,7 @@ pub(super) unsafe fn jsx_skip_trivia(
                     continue;
                 }
                 b'/' => {
-                    i = find_line_terminator(src, n, i + 2);
+                    i = find_line_terminator(src, n, i + 2, cpu);
                     continue;
                 }
                 _ => {}