[rvm-commits] SF.net SVN: jikesrvm:[15859] rvmroot/trunk/rvm/src/org/jikesrvm/objectmodel /JavaHeader.java

[<ste...@us...>]

Revision: 15859
          http://jikesrvm.svn.sourceforge.net/jikesrvm/?rev=15859&view=rev
Author:   steveb-oss
Date:     2010-06-17 05:02:34 +0000 (Thu, 17 Jun 2010)

Log Message:
-----------
Fix bug identified by Da Feng.   This bug is only evident when ADDRESS_BASED_HASHING is true and DYNAMIC_HASH_OFFSET is false, and a collector moves objects (as in a compacting collector).

Modified Paths:
--------------
    rvmroot/trunk/rvm/src/org/jikesrvm/objectmodel/JavaHeader.java

Modified: rvmroot/trunk/rvm/src/org/jikesrvm/objectmodel/JavaHeader.java
===================================================================
--- rvmroot/trunk/rvm/src/org/jikesrvm/objectmodel/JavaHeader.java	2010-06-17 04:43:34 UTC (rev 15858)
+++ rvmroot/trunk/rvm/src/org/jikesrvm/objectmodel/JavaHeader.java	2010-06-17 05:02:34 UTC (rev 15859)
@@ -456,7 +456,7 @@
     }
 
     if (toObj != null) {
-      toAddress = Magic.objectAsAddress(toObj).minus(OBJECT_REF_OFFSET);
+      toAddress = Magic.objectAsAddress(toObj).minus(objRefOffset);
     }
 
     // Low memory word of source object
@@ -464,13 +464,18 @@
 
     // Do the copy
     Memory.aligned32Copy(toAddress, fromAddress, copyBytes);
-    toObj = Magic.addressAsObject(toAddress.plus(objRefOffset));
 
+    if (toObj == null) {
+      toObj = Magic.addressAsObject(toAddress.plus(objRefOffset));
+    } else {
+      if (VM.VerifyAssertions) VM._assert(toObj == Magic.addressAsObject(toAddress.plus(objRefOffset)));
+    }
+
     // Do we need to copy the hash code?
     if (hashState.EQ(HASH_STATE_HASHED)) {
       int hashCode = Magic.objectAsAddress(fromObj).toWord().rshl(SizeConstants.LOG_BYTES_IN_ADDRESS).toInt();
       if (DYNAMIC_HASH_OFFSET) {
-        Magic.setIntAtOffset(toObj, Offset.fromIntSignExtend(numBytes - objRefOffset - HASHCODE_BYTES), hashCode);
+        Magic.setIntAtOffset(toObj, Offset.fromIntSignExtend(numBytes - OBJECT_REF_OFFSET - HASHCODE_BYTES), hashCode);
       } else {
         Magic.setIntAtOffset(toObj, HASHCODE_OFFSET, (hashCode << 1) | ALIGNMENT_MASK);
       }


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