Changeset 47022 in webkit for trunk/JavaScriptCore/debugger

Timestamp:

Aug 10, 2009, 9:35:02 PM (16 years ago)

Author:

[email protected]

Message:

Stack overflow crash in JavaScript garbage collector mark pass
​https://bugs.webkit.org/show_bug.cgi?id=12216

Reviewed by Gavin Barraclough and Sam Weinig

Make the GC mark phase iterative by using an explicit mark stack.
To do this marking any single object is performed in multiple stages

• The object is appended to the MarkStack, this sets the marked bit for the object using the new markDirect() function, and then returns
• When the MarkStack is drain()ed the object is popped off the stack and markChildren(MarkStack&) is called on the object to collect all of its children. drain() then repeats until the stack is empty.

Additionally I renamed a number of methods from 'mark' to 'markAggregate'
in order to make it more clear that marking of those object was not
going to result in an actual recursive mark.

Location:

trunk/JavaScriptCore/debugger

Files:

• DebuggerActivation.cpp (modified) (2 diffs)
• DebuggerActivation.h (modified) (2 diffs)

trunk/JavaScriptCore/debugger/DebuggerActivation.cpp

@@ -1 +1 @@
 /*
- * Copyright (C) 2008 Apple Inc. All rights reserved.
+ * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -39 +39 @@
 }
 
-void DebuggerActivation::mark()
+void DebuggerActivation::markChildren(MarkStack& markStack)
 {
-    JSObject::mark();
-    if (m_activation && !m_activation->marked())
-        m_activation->mark();
+    JSObject::markChildren(markStack);
+
+    if (m_activation)
+        markStack.append(m_activation);
 }
 

trunk/JavaScriptCore/debugger/DebuggerActivation.h

@@ -1 +1 @@
 /*
- * Copyright (C) 2008 Apple Inc. All rights reserved.
+ * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -37 +37 @@
         DebuggerActivation(JSObject*);
 
-        virtual void mark();
+        virtual void markChildren(MarkStack&);
         virtual UString className() const;
         virtual bool getOwnPropertySlot(ExecState*, const Identifier& propertyName, PropertySlot&);