Changeset 33983 in webkit for trunk/JavaScriptCore/VM

Timestamp:

May 21, 2008, 7:03:39 PM (17 years ago)

Author:

[email protected]

Message:

2008-05-21 Maciej Stachowiak <​[email protected]>

Reviewed by Darin.

• save a hash lookup wne writing to global properties 0.3% speedup on SunSpider, 7% on bitops-bitwise-and

• VM/Machine.cpp: (KJS::resolveBase): Check for being a the end of the scope chain before hash lookup.

File:

• trunk/JavaScriptCore/VM/Machine.cpp (modified) (2 diffs)

trunk/JavaScriptCore/VM/Machine.cpp

@@ -260 +260 @@
 
     ScopeChainIterator iter = scopeChain->begin();
+    ScopeChainIterator next = iter;
+    ++next;
     ScopeChainIterator end = scopeChain->end();
     ASSERT(iter != end);
@@ -266 +268 @@
     Identifier& ident = codeBlock->identifiers[property];
     JSObject* base;
-    do {
+    while (true) {
         base = *iter;
-        if (base->getPropertySlot(exec, ident, slot)) {
+        if (next == end || base->getPropertySlot(exec, ident, slot)) {
             r[dst].u.jsValue = base;
             return;
         }
-    } while (++iter != end);
-
-    r[dst].u.jsValue = base;
+        iter = next;
+        ++next;
+    }
 }