Bug 1874373 - Part 2: Call String.p.codePointAt in StringIteratorNext…

…. r=jandem Directly call `String.p.codePointAt` instead of manually computing the code point in `StringIteratorNext`. Depends on D198360 Differential Revision: https://phabricator.services.mozilla.com/D199350
dothq · Jan 24, 2024 · 1d625e0 · 1d625e0
1 parent 4936e43
commit 1d625e0
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Showing 4 changed files with 8 additions and 12 deletions.
diff --git a/js/src/builtin/String.cpp b/js/src/builtin/String.cpp
@@ -1893,7 +1893,7 @@ bool js::str_charCodeAt(JSContext* cx, unsigned argc, Value* vp) {
  *
  * ES2024 draft rev 7d2644968bd56d54d2886c012d18698ff3f72c35
  */
-static bool str_codePointAt(JSContext* cx, unsigned argc, Value* vp) {
+bool js::str_codePointAt(JSContext* cx, unsigned argc, Value* vp) {
   AutoJSMethodProfilerEntry pseudoFrame(cx, "String.prototype", "codePointAt");
   CallArgs args = CallArgsFromVp(argc, vp);
 

diff --git a/js/src/builtin/String.h b/js/src/builtin/String.h
@@ -36,6 +36,8 @@ extern bool str_toString(JSContext* cx, unsigned argc, Value* vp);
 
 extern bool str_charCodeAt(JSContext* cx, unsigned argc, Value* vp);
 
+extern bool str_codePointAt(JSContext* cx, unsigned argc, Value* vp);
+
 extern bool str_endsWith(JSContext* cx, unsigned argc, Value* vp);
 
 #if JS_HAS_INTL_API

diff --git a/js/src/builtin/String.js b/js/src/builtin/String.js
@@ -819,20 +819,12 @@ function StringIteratorNext() {
     return result;
   }
 
-  var charCount = 1;
-  var first = callFunction(std_String_charCodeAt, S, index);
-  if (first >= 0xd800 && first <= 0xdbff && index + 1 < size) {
-    var second = callFunction(std_String_charCodeAt, S, index + 1);
-    if (second >= 0xdc00 && second <= 0xdfff) {
-      first = (first - 0xd800) * 0x400 + (second - 0xdc00) + 0x10000;
-      charCount = 2;
-    }
-  }
+  var codePoint = callFunction(std_String_codePointAt, S, index);
+  var charCount = 1 + (codePoint > 0xffff);
 
   UnsafeSetReservedSlot(obj, ITERATOR_SLOT_NEXT_INDEX, index + charCount);
 
-  // Communicate |first|'s possible range to the compiler.
-  result.value = callFunction(std_String_fromCodePoint, null, first & 0x1fffff);
+  result.value = callFunction(std_String_fromCodePoint, null, codePoint);
 
   return result;
 }

diff --git a/js/src/vm/SelfHosting.cpp b/js/src/vm/SelfHosting.cpp
@@ -2299,6 +2299,8 @@ static const JSFunctionSpec intrinsic_functions[] = {
     JS_FN("std_Set_values", SetObject::values, 0, 0),
     JS_INLINABLE_FN("std_String_charCodeAt", str_charCodeAt, 1, 0,
                     StringCharCodeAt),
+    JS_INLINABLE_FN("std_String_codePointAt", str_codePointAt, 1, 0,
+                    StringCodePointAt),
     JS_INLINABLE_FN("std_String_endsWith", str_endsWith, 1, 0, StringEndsWith),
     JS_INLINABLE_FN("std_String_fromCharCode", str_fromCharCode, 1, 0,
                     StringFromCharCode),