Changeset 185368 in webkit for trunk/Source/JavaScriptCore/runtime/JSString.h

Timestamp:

Jun 9, 2015, 11:03:40 AM (10 years ago)

Author:

[email protected]

Message:

[JSC] JSString::getIndex() should avoid reifying substrings.
<​https://webkit.org/b/145803>

Reviewed by Darin Adler.

Implement getIndex() using JSString::view(), which cuts it down to a one-liner
and also avoids reifying substrings.

I saw 178 kB of reified substrings below operationGetByVal -> getIndex()
on cnet.com, so this should help.

• runtime/JSString.cpp:

(JSC::JSRopeString::getIndexSlowCase): Deleted.

• runtime/JSString.h:

(JSC::JSString::getIndex):

File:

• trunk/Source/JavaScriptCore/runtime/JSString.h (modified) (2 diffs)

trunk/Source/JavaScriptCore/runtime/JSString.h

@@ -373 +373 @@
     StringView view(ExecState*) const;
 
-    JS_EXPORT_PRIVATE JSString* getIndexSlowCase(ExecState*, unsigned);
-
     WriteBarrierBase<JSString>& fiber(unsigned i) const
     {
@@ -494 +492 @@
 {
     ASSERT(canGetIndex(i));
-    if (isRope())
-        return static_cast<JSRopeString*>(this)->getIndexSlowCase(exec, i);
-    ASSERT(i < m_value.length());
-    return jsSingleCharacterString(exec, m_value[i]);
+    return jsSingleCharacterString(exec, view(exec)[i]);
 }