Changeset 185659 in webkit for trunk/Source/JavaScriptCore/runtime/JSString.h

Timestamp:

Jun 17, 2015, 11:54:13 AM (10 years ago)

Author:

[email protected]

Message:

[JSC] jsSubstring() should have a fast path for 0..baseLength "substrings."
<​https://webkit.org/b/146051>

Reviewed by Anders Carlsson.

If asked to make a substring that actually spans the entire base string,
have jsSubstring() just return the base instead of allocating a new JSString.

3% speed-up on Octane/regexp.

• runtime/JSString.h:

(JSC::jsSubstring):

File:

• trunk/Source/JavaScriptCore/runtime/JSString.h (modified) (1 diff)

trunk/Source/JavaScriptCore/runtime/JSString.h

@@ -529 +529 @@
     if (!length)
         return vm.smallStrings.emptyString();
+    if (!offset && length == s->length())
+        return s;
     return JSRopeString::create(*exec, *s, offset, length);
 }