Changeset 37323 in webkit for trunk/JavaScriptCore/kjs

Timestamp:

Oct 5, 2008, 7:48:08 PM (17 years ago)

Author:

[email protected]

Message:

2008-10-05 Maciej Stachowiak <​[email protected]>

Reviewed by Oliver Hunt.

• fixed "REGRESSION (r37297): fast/js/deep-recursion-test takes too long and times out" ​https://bugs.webkit.org/show_bug.cgi?id=21375

The problem is that dynamicGlobalObject had become O(N) in number
of call frames, but unwinding the stack for an exception called it
for every call frame, resulting in O(N^{2) behavior for an
exception thrown from inside deep recursion.}

Instead of doing it that way, stash the dynamic global object in JSGlobalData.

• JavaScriptCore.exp:
• VM/Machine.cpp: (JSC::DynamicGlobalObjectScope::DynamicGlobalObjectScope): Helper class to temporarily store and later restore a dynamicGlobalObject in JSGlobalData. (JSC::DynamicGlobalObjectScope::~DynamicGlobalObjectScope): (JSC::Machine::execute): In each version, establish a DynamicGlobalObjectScope. For ProgramNode, always establish set new dynamicGlobalObject, for FunctionBody and Eval, only if none is currently set.
• VM/Machine.h:
• kjs/ExecState.h:
• kjs/JSGlobalData.cpp: (JSC::JSGlobalData::JSGlobalData): Ininitalize new dynamicGlobalObject field to 0.
• kjs/JSGlobalData.h:
• kjs/JSGlobalObject.h: (JSC::ExecState::dynamicGlobalObject): Moved here from ExecState for benefit of inlining. Return lexical global object if this is a globalExec(), otherwise look in JSGlobalData for the one stashed there.

Location:

trunk/JavaScriptCore/kjs

Files:

• ExecState.h (modified) (1 diff)
• JSGlobalData.cpp (modified) (1 diff)
• JSGlobalData.h (modified) (1 diff)
• JSGlobalObject.h (modified) (1 diff)

trunk/JavaScriptCore/kjs/ExecState.h

@@ -44 +44 @@
 
         // Global object in which execution began.
-        JSGlobalObject* dynamicGlobalObject()
-        {
-            return Machine::scopeChain(Machine::firstCallFrame(this))->globalObject();
-        }
+        JSGlobalObject* dynamicGlobalObject();
 
         // Global object in which the currently executing code was defined.

trunk/JavaScriptCore/kjs/JSGlobalData.cpp

@@ -92 +92 @@
     , parser(new Parser)
     , head(0)
+    , dynamicGlobalObject(0)
     , isSharedInstance(isShared)
     , clientData(0)

trunk/JavaScriptCore/kjs/JSGlobalData.h

@@ -99 +99 @@
 
         JSGlobalObject* head;
+        JSGlobalObject* dynamicGlobalObject;
 
         bool isSharedInstance;

trunk/JavaScriptCore/kjs/JSGlobalObject.h

@@ -331 +331 @@
     }
 
+    inline JSGlobalObject* ExecState::dynamicGlobalObject()
+    {
+        if (this == lexicalGlobalObject()->globalExec())
+            return lexicalGlobalObject();
+
+        // For any ExecState that's not a globalExec, the 
+        // dynamic global object must be set since code is running
+        ASSERT(globalData().dynamicGlobalObject);
+        return globalData().dynamicGlobalObject;
+    }
+    
 } // namespace JSC