1 files changed, 164 insertions, 0 deletions
diff --git a/js/src/builtin/RegExpLocalReplaceOpt.h.js b/js/src/builtin/RegExpLocalReplaceOpt.h.js
new file mode 100644
index 0000000000..35bb8a3bd9
--- /dev/null
+++ b/js/src/builtin/RegExpLocalReplaceOpt.h.js
@@ -0,0 +1,164 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Function template for the following functions:
+//   * RegExpLocalReplaceOpt
+//   * RegExpLocalReplaceOptFunc
+//   * RegExpLocalReplaceOptSubst
+// Define the following macro and include this file to declare function:
+//   * FUNC_NAME     -- function name (required)
+//       e.g.
+//         #define FUNC_NAME RegExpLocalReplaceOpt
+// Define the following macro (without value) to switch the code:
+//   * SUBSTITUTION     -- replaceValue is a string with "$"
+//   * FUNCTIONAL       -- replaceValue is a function
+//   * SHORT_STRING     -- replaceValue is a string without "$" and lengthS < 0x7fff
+//   * neither of above -- replaceValue is a string without "$"
+
+// ES2023 draft rev 2c78e6f6b5bc6bfbf79dd8a12a9593e5b57afcd2
+// 22.2.5.11 RegExp.prototype [ @@replace ] ( string, replaceValue )
+// Steps 12.a-17.
+// Optimized path for @@replace with the following conditions:
+//   * global flag is false
+function FUNC_NAME(
+  rx,
+  S,
+  lengthS,
+  replaceValue,
+#ifdef SUBSTITUTION
+  firstDollarIndex
+#endif
+) {
+  // 21.2.5.2.2 RegExpBuiltinExec, step 4.
+  var lastIndex = ToLength(rx.lastIndex);
+
+  // 21.2.5.2.2 RegExpBuiltinExec, step 5.
+  // Side-effects in step 4 can recompile the RegExp, so we need to read the
+  // flags again and handle the case when global was enabled even though this
+  // function is optimized for non-global RegExps.
+  var flags = UnsafeGetInt32FromReservedSlot(rx, REGEXP_FLAGS_SLOT);
+
+  // 21.2.5.2.2 RegExpBuiltinExec, steps 6-7.
+  var globalOrSticky = !!(flags & (REGEXP_GLOBAL_FLAG | REGEXP_STICKY_FLAG));
+
+  if (globalOrSticky) {
+    // 21.2.5.2.2 RegExpBuiltinExec, step 12.a.
+    if (lastIndex > lengthS) {
+      if (globalOrSticky) {
+        rx.lastIndex = 0;
+      }
+
+      // Steps 12-16.
+      return S;
+    }
+  } else {
+    // 21.2.5.2.2 RegExpBuiltinExec, step 8.
+    lastIndex = 0;
+  }
+
+#if !defined(SHORT_STRING)
+  // Step 12.a.
+  var result = RegExpMatcher(rx, S, lastIndex);
+
+  // Step 12.b.
+  if (result === null) {
+    // 21.2.5.2.2 RegExpBuiltinExec, steps 12.a.i, 12.c.i.
+    if (globalOrSticky) {
+      rx.lastIndex = 0;
+    }
+
+    // Steps 13-17.
+    return S;
+  }
+#else
+  // Step 12.a.
+  var result = RegExpSearcher(rx, S, lastIndex);
+
+  // Step 12.b.
+  if (result === -1) {
+    // 21.2.5.2.2 RegExpBuiltinExec, steps 12.a.i, 12.c.i.
+    if (globalOrSticky) {
+      rx.lastIndex = 0;
+    }
+
+    // Steps 13-17.
+    return S;
+  }
+#endif
+
+  // Steps 12.c, 13-14.
+
+#if !defined(SHORT_STRING)
+  // Steps 15.a-b.
+  assert(result.length >= 1, "RegExpMatcher doesn't return an empty array");
+
+  // Step 15.c.
+  var matched = result[0];
+
+  // Step 15.d.
+  var matchLength = matched.length;
+
+  // Step 15.e-f.
+  var position = result.index;
+
+  // Step 15.m.iii (reordered)
+  // To set rx.lastIndex before RegExpGetFunctionalReplacement.
+  var nextSourcePosition = position + matchLength;
+#else
+  // Steps 15.a-d (skipped).
+
+  // Step 15.e-f.
+  var position = result & 0x7fff;
+
+  // Step 15.m.iii (reordered)
+  var nextSourcePosition = (result >> 15) & 0x7fff;
+#endif
+
+  // 21.2.5.2.2 RegExpBuiltinExec, step 15.
+  if (globalOrSticky) {
+    rx.lastIndex = nextSourcePosition;
+  }
+
+  var replacement;
+  // Steps 15.g-l.
+#if defined(FUNCTIONAL)
+  replacement = RegExpGetFunctionalReplacement(
+    result,
+    S,
+    position,
+    replaceValue
+  );
+#elif defined(SUBSTITUTION)
+  // Step 15.l.i
+  var namedCaptures = result.groups;
+  if (namedCaptures !== undefined) {
+    namedCaptures = ToObject(namedCaptures);
+  }
+  // Step 15.l.ii
+  replacement = RegExpGetSubstitution(
+    result,
+    S,
+    position,
+    replaceValue,
+    firstDollarIndex,
+    namedCaptures
+  );
+#else
+  replacement = replaceValue;
+#endif
+
+  // Step 15.m.ii.
+  var accumulatedResult = Substring(S, 0, position) + replacement;
+
+  // Step 16.
+  if (nextSourcePosition >= lengthS) {
+    return accumulatedResult;
+  }
+
+  // Step 17.
+  return (
+    accumulatedResult +
+    Substring(S, nextSourcePosition, lengthS - nextSourcePosition)
+  );
+}