Changeset 29818 in webkit for trunk/JavaScriptCore/kjs/object.cpp

Timestamp:

Jan 27, 2008, 1:38:01 AM (17 years ago)

Author:

Darin Adler

Message:

JavaScriptCore:

Reviewed by Oliver.

• fix <rdar://problem/5657450> REGRESSION: const is broken

Test: fast/js/const.html

SunSpider said this was 0.3% slower. And I saw some Shark samples in
JSGlobalObject::put -- not a lot but a few. We may be able to regain the
speed, but for now we will take that small hit for correctness sake.

• kjs/JSGlobalObject.cpp: (KJS::JSGlobalObject::put): Pass the checkReadOnly flag in to symbolTablePut instead of passing attributes.

• kjs/JSVariableObject.h: (KJS::JSVariableObject::symbolTablePut): Removed the code to set attributes here, since we only set attributes when creating a property. Added the code to check read-only here, since we need that to implement const!

• kjs/function.cpp: (KJS::ActivationImp::put): Pass the checkReadOnly flag in to symbolTablePut instead of passing attributes.

• kjs/nodes.cpp: (KJS::isConstant): Added. (KJS::PostIncResolveNode::optimizeVariableAccess): Create a PostIncConstNode if optimizing for a local variable and the variable is constant. (KJS::PostDecResolveNode::optimizeVariableAccess): Ditto. But PostDecConstNode. (KJS::PreIncResolveNode::optimizeVariableAccess): Ditto. But PreIncConstNode. (KJS::PreDecResolveNode::optimizeVariableAccess): Ditto. But PreDecConstNode. (KJS::PreIncConstNode::evaluate): Return the value + 1. (KJS::PreDecConstNode::evaluate): Return the value - 1. (KJS::PostIncConstNode::evaluate): Return the value converted to a number. (KJS::PostDecConstNode::evaluate): Ditto. (KJS::ReadModifyResolveNode::optimizeVariableAccess): Create a ReadModifyConstNode if optimizing for a local variable and the variable is constant. (KJS::AssignResolveNode::optimizeVariableAccess): Ditto. But AssignConstNode. (KJS::ScopeNode::optimizeVariableAccess): Pass the local storage to the node optimizeVariableAccess functions, since that's where we need to look to figure out if a variable is constant. (KJS::FunctionBodyNode::processDeclarations): Moved the call to optimizeVariableAccess until after localStorage is set up. (KJS::ProgramNode::processDeclarations): Ditto.

• kjs/nodes.h: Fixed the IsConstant and HasInitializer values. They are used as flag masks, so a value of 0 will not work for IsConstant. Changed the first parameter to optimizeVariableAccess to be a const reference to a symbol table and added a const reference to local storage. Added classes for const versions of local variable access: PostIncConstNode, PostDecConstNode, PreIncConstNode, PreDecConstNode, ReadModifyConstNode, and AssignConstNode.

• kjs/object.cpp: (KJS::JSObject::put): Tweaked comments a bit, and changed the checkReadOnly expression to match the form used at the two other call sites.

LayoutTests:

Reviewed by Oliver.

• tests for <rdar://problem/5657450> REGRESSION: const is broken

• fast/js/const-expected.txt: Updated with results that express success rather than failure, and to include the many new tests I added.
• fast/js/kde/const-expected.txt: Ditto.
• fast/js/resources/const.js: Added many new tests, covering the various cases of const in globals, function locals, the slow case inside eval, the different node types, and the values of the expressions.

File:

• trunk/JavaScriptCore/kjs/object.cpp (modified) (2 diffs)

trunk/JavaScriptCore/kjs/object.cpp

@@ -209 +209 @@
   ASSERT(value);
 
-  // non-standard netscape extension
   if (propertyName == exec->propertyNames().underscoreProto) {
     JSObject* proto = value->getObject();
@@ -222 +221 @@
   }
 
-  /* TODO: check for write permissions directly w/o this call */
-  /* Doesn't look very easy with the PropertyMap API - David */
-  // putValue() is used for JS assignemnts. It passes no attribute.
-  // Assume that a C++ implementation knows what it is doing
-  // and let it override the canPut() check.
-  bool checkReadOnly = !(attr & (ReadOnly | DontEnum | Internal | Function | GetterSetter));
+  // The put calls from JavaScript execution either have no attributes set, or in some cases
+  // have DontDelete set. For those calls, respect the ReadOnly flag.
+  bool checkReadOnly = !(attr & ~DontDelete);
+
   // Check if there are any setters or getters in the prototype chain
   JSObject *obj = this;