Changeset 37712 in webkit for trunk/JavaScriptCore/kjs/JSImmediate.h

Timestamp:

Oct 19, 2008, 10:58:02 PM (17 years ago)

Author:

Darin Adler

Message:

2008-10-19 Darin Adler <Darin Adler>

Reviewed by Cameron Zwarich.

• next step of ​https://bugs.webkit.org/show_bug.cgi?id=21732 improve performance by eliminating JSValue as a base class for JSCell

Change JSValuePtr from a typedef into a class. This allows us to support
conversion from JSCell* to JSValuePtr even if JSCell isn't derived from
JSValue.

• JavaScriptCore.exp: Updated symbols that involve JSValuePtr, since it's now a distinct type.

• API/APICast.h: (toRef): Extract the JSValuePtr payload explicitly since we can't just cast any more.
• VM/CTI.cpp: (JSC::CTI::asInteger): Ditto.

• VM/CodeGenerator.cpp: (JSC::CodeGenerator::addConstant): Get at the payload directly. (JSC::CodeGenerator::emitLoad): Added an overload of JSCell* because otherwise classes derived from JSValue end up calling the bool overload instead of JSValuePtr.
• VM/CodeGenerator.h: Ditto. Also update traits to use JSValue* and the payload functions.

• VM/Register.h: Added a JSCell* overload and use of payload functions.

• kjs/JSCell.h: (JSC::asCell): Use payload function. (JSC::JSValue::asCell): Use JSValue* instead of JSValuePtr. (JSC::JSValuePtr::JSValuePtr): Added. Constructor that takes JSCell* and creates a JSValuePtr.

• kjs/JSImmediate.h: Added JSValuePtr class. Also updated makeValue and makeInt to work with JSValue* and the payload function.

• kjs/JSValue.h: Added == and != operators for JSValuePtr. Put them here because eventually all the JSValue functions should go here except what's needed by JSImmediate. Also fix asValue to use JSValue* instead of JSValuePtr.

• kjs/PropertySlot.h: Change constructor to take JSValuePtr.

• kjs/protect.h: Update gcProtect functions to work with JSCell* as well as JSValuePtr. Also updated the ProtectedPtr<JSValuePtr> specialization to work more directly. Also changed all the call sites to use gcProtectNullTolerant.

File:

• trunk/JavaScriptCore/kjs/JSImmediate.h (modified) (3 diffs)

trunk/JavaScriptCore/kjs/JSImmediate.h

@@ -35 +35 @@
 
     class ExecState;
+    class JSCell;
     class JSObject;
     class JSValue;
     class UString;
 
-    typedef JSValue* JSValuePtr;
-
-    inline JSValuePtr noValue() { return 0; }
-    inline void* asPointer(JSValuePtr value) { return value; }
+    class JSValuePtr {
+    public:
+        JSValuePtr() { } // uninitialized (not zero)
+        JSValuePtr(const JSValue* payload) : m_payload(const_cast<JSValue*>(payload)) { }
+        JSValuePtr(const JSCell*);
+
+        JSValue* payload() const { return m_payload; }
+        JSValue** payloadPtr() { return &m_payload; }
+
+        bool operator!() const { return !payload(); }
+    
+        // This conversion operator allows implicit conversion to bool but not to other integer types.
+        typedef JSValue* JSValuePtr::*UnspecifiedBoolType;
+        operator UnspecifiedBoolType() const { return payload() ? &JSValuePtr::m_payload : 0; }
+
+        JSValue* operator->() const { return payload(); }
+
+    private:
+        JSValue* m_payload;
+    };
+
+    inline JSValuePtr noValue() { return static_cast<JSValue*>(0); }
+    inline void* asPointer(JSValuePtr value) { return value.payload(); }
 
     /*
@@ -262 +282 @@
         static ALWAYS_INLINE JSValuePtr makeValue(uintptr_t integer)
         {
-            return reinterpret_cast<JSValuePtr>(integer);
+            return reinterpret_cast<JSValue*>(integer);
         }
 
@@ -302 +322 @@
         static ALWAYS_INLINE uintptr_t rawValue(JSValuePtr v)
         {
-            return reinterpret_cast<uintptr_t>(v);
+            return reinterpret_cast<uintptr_t>(v.payload());
         }