Changeset 170677 in webkit for trunk/Source/JavaScriptCore/debugger/Breakpoint.h

Timestamp:

Jul 1, 2014, 4:40:32 PM (11 years ago)

Author:

[email protected]

Message:

Debugger's breakpoint list should not be a Vector.
<​https://webkit.org/b/134514>

Reviewed by Geoffrey Garen.

The debugger currently stores breakpoint data as entries in a Vector (see
BreakpointsInLine). It also keeps a fast map look up of breakpoint IDs to
the breakpoint data (see m_breakpointIDToBreakpoint). Because a Vector can
compact or reallocate its backing store, this can causes all sorts of havoc.
The m_breakpointIDToBreakpoint map assumes that the breakpoint data doesn't
move in memory.

The fix is to replace the BreakpointsInLine Vector with a BreakpointsList
doubly linked list.

• debugger/Breakpoint.h:

(JSC::Breakpoint::Breakpoint):
(JSC::BreakpointsList::~BreakpointsList):

• debugger/Debugger.cpp:

(JSC::Debugger::setBreakpoint):
(JSC::Debugger::removeBreakpoint):
(JSC::Debugger::hasBreakpoint):

• debugger/Debugger.h:

File:

• trunk/Source/JavaScriptCore/debugger/Breakpoint.h (modified) (3 diffs)

trunk/Source/JavaScriptCore/debugger/Breakpoint.h

@@ -28 +28 @@
 
 #include "DebuggerPrimitives.h"
+#include <wtf/DoublyLinkedList.h>
+#include <wtf/RefCounted.h>
 #include <wtf/text/WTFString.h>
 
 namespace JSC {
 
-struct Breakpoint {
+struct Breakpoint : public DoublyLinkedListNode<Breakpoint> {
     Breakpoint()
         : id(noBreakpointID)
@@ -52 +54 @@
     }
 
+    Breakpoint(const Breakpoint& other)
+        : id(other.id)
+        , sourceID(other.sourceID)
+        , line(other.line)
+        , column(other.column)
+        , condition(other.condition)
+        , autoContinue(other.autoContinue)
+    {
+    }
+
     BreakpointID id;
     SourceID sourceID;
@@ -60 +72 @@
 
     static const unsigned unspecifiedColumn = UINT_MAX;
+
+private:
+    Breakpoint* m_prev;
+    Breakpoint* m_next;
+
+    friend class WTF::DoublyLinkedListNode<Breakpoint>;
+};
+
+class BreakpointsList : public DoublyLinkedList<Breakpoint>,
+    public RefCounted<BreakpointsList> {
+public:
+    ~BreakpointsList()
+    {
+        Breakpoint* breakpoint;
+        while ((breakpoint = removeHead()))
+            delete breakpoint;
+        ASSERT(isEmpty());
+    }
 };