Contribution 015 from Robin Garner of ANU.

Generalization of pointer enumeration mechanism
JikesRVM · Jun 24, 2003 · e7195af · e7195af
1 parent 74ced16
commit e7195af
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Showing 9 changed files with 53 additions and 31 deletions.
diff --git a/MMTk/src/org/mmtk/plan/BasePlan.java b/MMTk/src/org/mmtk/plan/BasePlan.java
@@ -102,6 +102,7 @@ public abstract class BasePlan
   //
   private int id = 0;                     // Zero-based id of plan instance
   public BumpPointer immortal;
+  public Enumerate enum;
 
   ////////////////////////////////////////////////////////////////////////////
   //
@@ -138,6 +139,7 @@ public abstract class BasePlan
     id = planCount++;
     plans[id] = (Plan) this;
     immortal = new BumpPointer(immortalVM);
+    enum = new Enumerate((Plan) this);
   }
 
   /**

diff --git a/MMTk/src/org/mmtk/policy/RefCountLocal.java b/MMTk/src/org/mmtk/policy/RefCountLocal.java
@@ -296,7 +296,7 @@ else if (Plan.refCountCycleDetection)
   private final void release(VM_Address object) 
     throws VM_PragmaInline {
     // this object is now dead, scan it for recursive decrement
-    ScanObject.enumeratePointers(object, plan);
+    ScanObject.enumeratePointers(object, plan.enum);
     if (!Plan.refCountCycleDetection ||	!RCBaseHeader.isBuffered(object)) 
       free(object);
   }

diff --git a/MMTk/src/org/mmtk/utility/TrialDeletion.java b/MMTk/src/org/mmtk/utility/TrialDeletion.java
@@ -376,7 +376,7 @@ private final void markGrey(VM_Address object)
       visitCount++;
       if (!RCBaseHeader.isGrey(object)) {
 	RCBaseHeader.makeGrey(object);
-	ScanObject.enumeratePointers(object, plan);
+	ScanObject.enumeratePointers(object, plan.enum);
       }
       object = workQueue.pop();
     }
@@ -393,7 +393,7 @@ private final void scan(VM_Address object)
 	  phase = SCAN;
 	} else {
 	  RCBaseHeader.makeWhite(object);
-	  ScanObject.enumeratePointers(object, plan);
+	  ScanObject.enumeratePointers(object, plan.enum);
 	}
       } 
       object = workQueue.pop();
@@ -407,7 +407,7 @@ private final void scanBlack(VM_Address object)
       //      if (!SimpleRCBaseHeader.isGreen(object)) {
       if (!RCBaseHeader.isBlack(object)) {  // FIXME can't this just be if (isGrey(object)) ??
 	RCBaseHeader.makeBlack(object);
-	ScanObject.enumeratePointers(object, plan);
+	ScanObject.enumeratePointers(object, plan.enum);
       }
       object = blackQueue.pop();
     }
@@ -418,7 +418,7 @@ private final void collectWhite(VM_Address object)
     while (!object.isZero()) {
       if (RCBaseHeader.isWhite(object) && !RCBaseHeader.isBuffered(object)) {
 	RCBaseHeader.makeBlack(object);
-	ScanObject.enumeratePointers(object, plan);
+	ScanObject.enumeratePointers(object, plan.enum);
 	freeBuffer.push(object);
       }
       object = workQueue.pop();

diff --git a/rvm/src/vm/memoryManagers/JMTk/plan/BasePlan.java b/rvm/src/vm/memoryManagers/JMTk/plan/BasePlan.java
@@ -102,6 +102,7 @@ public abstract class BasePlan
   //
   private int id = 0;                     // Zero-based id of plan instance
   public BumpPointer immortal;
+  public Enumerate enum;
 
   ////////////////////////////////////////////////////////////////////////////
   //
@@ -138,6 +139,7 @@ public abstract class BasePlan
     id = planCount++;
     plans[id] = (Plan) this;
     immortal = new BumpPointer(immortalVM);
+    enum = new Enumerate((Plan) this);
   }
 
   /**

diff --git a/rvm/src/vm/memoryManagers/JMTk/plan/Enumerate.java b/rvm/src/vm/memoryManagers/JMTk/plan/Enumerate.java
@@ -0,0 +1,33 @@
+package com.ibm.JikesRVM.memoryManagers.JMTk;
+
+import com.ibm.JikesRVM.VM_Address;
+import com.ibm.JikesRVM.VM_PragmaInline;
+import com.ibm.JikesRVM.VM_Uninterruptible;
+
+//$Id:
+
+/**
+ * Callbacks from ScanObject to Plan.enumeratePointerLocation are
+ * dispatched through an object of this class, so that we have the
+ * opportunity to change the behaviour through sub-classing. <p>
+ *
+ * @author Robin Garner
+ * @version $Revision$
+ * @date    $Date$
+ */
+
+public class Enumerate implements VM_Uninterruptible {
+  private Plan plan;
+
+  /* Constructor 
+   */
+
+  Enumerate(Plan plan) { 
+    this.plan = plan; 
+  }
+
+  public void enumeratePointerLocation(VM_Address location) 
+      throws VM_PragmaInline {
+    plan.enumeratePointerLocation(location);
+  }
+}
diff --git a/rvm/src/vm/memoryManagers/JMTk/policy/RefCountLocal.java b/rvm/src/vm/memoryManagers/JMTk/policy/RefCountLocal.java
@@ -296,7 +296,7 @@ else if (Plan.refCountCycleDetection)
   private final void release(VM_Address object) 
     throws VM_PragmaInline {
     // this object is now dead, scan it for recursive decrement
-    ScanObject.enumeratePointers(object, plan);
+    ScanObject.enumeratePointers(object, plan.enum);
     if (!Plan.refCountCycleDetection ||	!RCBaseHeader.isBuffered(object)) 
       free(object);
   }

diff --git a/rvm/src/vm/memoryManagers/JMTk/utility/TrialDeletion.java b/rvm/src/vm/memoryManagers/JMTk/utility/TrialDeletion.java
@@ -376,7 +376,7 @@ private final void markGrey(VM_Address object)
       visitCount++;
       if (!RCBaseHeader.isGrey(object)) {
 	RCBaseHeader.makeGrey(object);
-	ScanObject.enumeratePointers(object, plan);
+	ScanObject.enumeratePointers(object, plan.enum);
       }
       object = workQueue.pop();
     }
@@ -393,7 +393,7 @@ private final void scan(VM_Address object)
 	  phase = SCAN;
 	} else {
 	  RCBaseHeader.makeWhite(object);
-	  ScanObject.enumeratePointers(object, plan);
+	  ScanObject.enumeratePointers(object, plan.enum);
 	}
       } 
       object = workQueue.pop();
@@ -407,7 +407,7 @@ private final void scanBlack(VM_Address object)
       //      if (!SimpleRCBaseHeader.isGreen(object)) {
       if (!RCBaseHeader.isBlack(object)) {  // FIXME can't this just be if (isGrey(object)) ??
 	RCBaseHeader.makeBlack(object);
-	ScanObject.enumeratePointers(object, plan);
+	ScanObject.enumeratePointers(object, plan.enum);
       }
       object = blackQueue.pop();
     }
@@ -418,7 +418,7 @@ private final void collectWhite(VM_Address object)
     while (!object.isZero()) {
       if (RCBaseHeader.isWhite(object) && !RCBaseHeader.isBuffered(object)) {
 	RCBaseHeader.makeBlack(object);
-	ScanObject.enumeratePointers(object, plan);
+	ScanObject.enumeratePointers(object, plan.enum);
 	freeBuffer.push(object);
       }
       object = workQueue.pop();

diff --git a/rvm/src/vm/memoryManagers/JMTk/vmInterface/ScanObject.java b/rvm/src/vm/memoryManagers/JMTk/vmInterface/ScanObject.java
@@ -5,7 +5,7 @@
 
 package com.ibm.JikesRVM.memoryManagers.vmInterface;
 
-import com.ibm.JikesRVM.memoryManagers.JMTk.Plan;
+import com.ibm.JikesRVM.memoryManagers.JMTk.Enumerate;
 
 import com.ibm.JikesRVM.classloader.*;
 import com.ibm.JikesRVM.VM;
@@ -61,9 +61,9 @@ public static void rootScan(Object objRef)
    * @param object The object to be scanned.
    * @param plan The plan with respect to which the callback should be made.
    */
-  public static void enumeratePointers(VM_Address object, Plan plan) 
+  public static void enumeratePointers(VM_Address object, Enumerate enum) 
     throws VM_PragmaUninterruptible, VM_PragmaInline {
-    scan(object, false, plan, false);
+    scan(object, false, enum, false);
   }
 
   /**
@@ -72,7 +72,7 @@ public static void enumeratePointers(VM_Address object, Plan plan)
    *
    * @param objRef  reference for object to be scanned (as int)
    */
-  private static void scan(VM_Address objRef, boolean root, Plan plan,
+  private static void scan(VM_Address objRef, boolean root, Enumerate enum,
 			   boolean trace)
     throws VM_PragmaUninterruptible, VM_PragmaInline {
 
@@ -109,7 +109,7 @@ private static void scan(VM_Address objRef, boolean root, Plan plan,
 	if (trace)
 	  MM_Interface.processPtrField(objRef.add(referenceOffsets[i]), root);
 	else
-	  VM_Interface.enumeratePtrLoc(objRef.add(referenceOffsets[i]), plan);
+	  enum.enumeratePointerLocation(objRef.add(referenceOffsets[i]));
       }
       Statistics.profileScan(obj, 4 * referenceOffsets.length, tib);
     }
@@ -125,7 +125,7 @@ private static void scan(VM_Address objRef, boolean root, Plan plan,
 	  if (trace)
 	    MM_Interface.processPtrField(location, root);
 	  else
-	    VM_Interface.enumeratePtrLoc(location, plan);
+	    enum.enumeratePointerLocation(location);
           location = location.add(WORD_SIZE);  // is this size_of_pointer ?
         }
         Statistics.profileScan(obj, numBytes, tib);

diff --git a/rvm/src/vm/memoryManagers/JMTk/vmInterface/VM_Interface.java b/rvm/src/vm/memoryManagers/JMTk/vmInterface/VM_Interface.java
@@ -299,21 +299,6 @@ public static void scheduleFinalizerThread () throws VM_PragmaUninterruptible {
     }
   }
 
-  /**
-   * A pointer location has been enumerated by ScanObject.  This is
-   * the callback method, allowing the plan to perform an action with
-   * respect to that location.
-   *
-   * @param location An address known to contain a pointer.  The
-   * location is within the object being scanned by ScanObject.
-   * @param plan The plan that initiated the object scan.  A callback
-   * should be made to this plan.
-   */
-  public static void enumeratePtrLoc(VM_Address location, Plan plan)
-    throws VM_PragmaUninterruptible, VM_PragmaInline { 
-    plan.enumeratePointerLocation(location);
-  }
-
   private static SynchronizedCounter threadCounter = new SynchronizedCounter();
   public static void resetComputeAllRoots() {
     threadCounter.reset();