Changeset 34541 in webkit for trunk/JavaScriptCore/VM/Machine.cpp

Timestamp:

Jun 14, 2008, 3:13:18 PM (17 years ago)

Author:

[email protected]

Message:

2008-06-14 Maciej Stachowiak <​[email protected]>

Reviewed by Oliver.

• initialize local vars as side effect of call instead of in bytecode 1.004x speedup on SunSpider.

This removes just the dispatch overhead for these loads - in the
future, dead store elimination might be able to eliminate them
entirely.

• VM/CodeGenerator.cpp: (KJS::CodeGenerator::CodeGenerator): For function blocks, don't emit loads of undefined for var initialization.
• VM/Machine.cpp: (KJS::slideRegisterWindowForCall): Instead, initialize locals as part of the call.

File:

• trunk/JavaScriptCore/VM/Machine.cpp (modified) (1 diff)

trunk/JavaScriptCore/VM/Machine.cpp

@@ -405 +405 @@
             *(it + shift) = *it;
     }
+    
+    // initialize local variable slots
+    for (Register* it = r - newCodeBlock->numVars; it != r; ++it)
+        (*it).u.jsValue = jsUndefined();
 
     return r;