boehm.cc (_Jv_BuildGCDescr): Put first word of object in most significant bit of descriptor.

	* boehm.cc (_Jv_BuildGCDescr): Put first word of object in most
	significant bit of descriptor. Include the vtable and sync_info
	fields.

From-SVN: r71895

libjava/ChangeLog

+2003-09-29  Bryce McKinlay  <bryce@mckinlay.net.nz>
+
+	* boehm.cc (_Jv_BuildGCDescr): Put first word of object in most 
+	significant bit of descriptor. Include the vtable and sync_info 
+	fields.
+
 2003-09-28  Bryce McKinlay  <bryce@mckinlay.net.nz>
 
 	* java/text/DateFormat.java (format): Throw IllegalArgumentException

libjava/boehm.cc

@@ -331,12 +331,20 @@ void *
 _Jv_BuildGCDescr(jclass self)
 {
   jlong desc = 0;
+  jint bits_per_word = CHAR_BIT * sizeof (void *);
 
   // Note: for now we only consider a bitmap mark descriptor.  We
   // could also handle the case where the first N fields of a type are
   // references.  However, this is not very likely to be used by many
   // classes, and it is easier to compute things this way.
 
+  // The vtable pointer.
+  desc |= 1ULL << (bits_per_word - 1);
+#ifndef JV_HASH_SYNCHRONIZATION
+  // The sync_info field.
+  desc |= 1ULL << (bits_per_word - 2);
+#endif
+
   for (jclass klass = self; klass != NULL; klass = klass->getSuperclass())
     {
       jfieldID field = JvGetFirstInstanceField(klass);
@@ -351,13 +359,12 @@ _Jv_BuildGCDescr(jclass self)
 	      if (off % sizeof (void *) != 0)
 		return (void *) (GCJ_DEFAULT_DESCR);
 	      off /= sizeof (void *);
-	      // Bottom 2 bits are reserved.
-	      off += 2;
 	      // If we find a field outside the range of our bitmap,
-	      // fall back to procedure marker.
-	      if (off > CHAR_BIT * sizeof (void *))
+	      // fall back to procedure marker. The bottom 2 bits are
+	      // reserved.
+	      if (off >= bits_per_word - 2)
 		return (void *) (GCJ_DEFAULT_DESCR);
-	      desc |= 1ULL << off;
+	      desc |= 1ULL << (bits_per_word - off - 1);
 	    }
 
 	  field = field->getNextField();