[JSC] Use int32 serialization for double stringifying in JSStringJoiner

https://bugs.webkit.org/show_bug.cgi?id=257995 rdar://110682175 Reviewed by Mark Lam. Add int32 fast path for double stringifying in JSStringJoiner. * Source/JavaScriptCore/runtime/ArrayPrototype.cpp: (JSC::JSC_DEFINE_HOST_FUNCTION): * Source/JavaScriptCore/runtime/JSStringJoiner.h: (JSC::JSStringJoiner::appendNumber): Canonical link: https://commits.webkit.org/265102@main
WebKit · Jun 13, 2023 · ad54954 · ad54954
1 parent 4274ce7
commit ad54954
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Showing 2 changed files with 5 additions and 2 deletions.
diff --git a/Source/JavaScriptCore/runtime/ArrayPrototype.cpp b/Source/JavaScriptCore/runtime/ArrayPrototype.cpp
@@ -526,7 +526,7 @@ JSC_DEFINE_HOST_FUNCTION(arrayProtoFuncToString, (JSGlobalObject* globalObject,
     RETURN_IF_EXCEPTION(scope, encodedJSValue());
 
     Integrity::auditStructureID(thisObject->structureID());
-    if (!canUseDefaultArrayJoinForToString(thisObject)) {
+    if (UNLIKELY(!canUseDefaultArrayJoinForToString(thisObject))) {
         // 2. Let func be the result of calling the [[Get]] internal method of array with argument "join".
         JSValue function = thisObject->get(globalObject, vm.propertyNames->join);
         RETURN_IF_EXCEPTION(scope, encodedJSValue());

diff --git a/Source/JavaScriptCore/runtime/JSStringJoiner.h b/Source/JavaScriptCore/runtime/JSStringJoiner.h
@@ -197,7 +197,10 @@ ALWAYS_INLINE void JSStringJoiner::appendNumber(VM& vm, int32_t value)
 
 ALWAYS_INLINE void JSStringJoiner::appendNumber(VM& vm, double value)
 {
-    append8Bit(vm.numericStrings.add(value));
+    if (canBeStrictInt32(value))
+        appendNumber(vm, static_cast<int32_t>(value));
+    else
+        append8Bit(vm.numericStrings.add(value));
 }
 
 } // namespace JSC