Changeset 35309 in webkit for trunk/JavaScriptCore/VM/CodeGenerator.h

Timestamp:

Jul 23, 2008, 5:49:46 PM (17 years ago)

Author:

[email protected]

Message:

Improve switch performance.

Reviewed by Geoff Garen and Sam Weinig.

Improve switch performance by converting to a hashmap based jump
table to avoid the sequence of dispatches that would otherwise be
needed. This results in a 9-19x performance win for string switches
based on ad hoc testing, and a 6x improvement for integer switch
statements. SunSpider reports a 1.2% progression.

File:

• trunk/JavaScriptCore/VM/CodeGenerator.h (modified) (2 diffs)

trunk/JavaScriptCore/VM/CodeGenerator.h

@@ -314 +314 @@
         JumpContext* jumpContextForBreak(const Identifier&);
 
+        void beginSwitch(RegisterID*, SwitchInfo::SwitchType);
+        void endSwitch(uint32_t clauseCount, RefPtr<LabelID>*, ExpressionNode**, LabelID* defaultLabel, int32_t min, int32_t range);
+
         CodeType codeType() const { return m_codeType; }
 
@@ -402 +405 @@
         int m_continueDepth;
         Vector<ControlFlowContext> m_scopeContextStack;
+        Vector<SwitchInfo> m_switchContextStack;
 
         int m_nextVar;