# HG changeset patch
# User drwhite
# Date 1466460727 14400
#      Mon Jun 20 18:12:07 2016 -0400
# Node ID d2b21bd3dae01a5eb9b49161c8e6c817ac99f263
# Parent  7862a718ec47bf061efeb6b0ed801fc848a3ab0d
[mq]: webrev.01

diff --git a/src/share/vm/classfile/javaClasses.cpp b/src/share/vm/classfile/javaClasses.cpp
--- a/src/share/vm/classfile/javaClasses.cpp
+++ b/src/share/vm/classfile/javaClasses.cpp
@@ -871,12 +871,16 @@
 
 int  java_lang_Class::oop_size(oop java_class) {
   assert(_oop_size_offset != 0, "must be set");
-  return java_class->int_field(_oop_size_offset);
+  int size = java_class->int_field(_oop_size_offset);
+  assert(size > 0, "size not set or stomped on: %d", size);
+  return size;
 }
 void java_lang_Class::set_oop_size(oop java_class, int size) {
   assert(_oop_size_offset != 0, "must be set");
+  assert(size > 0, "total object size must be positive: %d", size);
   java_class->int_field_put(_oop_size_offset, size);
 }
+
 int  java_lang_Class::static_oop_field_count(oop java_class) {
   assert(_static_oop_field_count_offset != 0, "must be set");
   return java_class->int_field(_static_oop_field_count_offset);
diff --git a/src/share/vm/gc/cms/concurrentMarkSweepGeneration.cpp b/src/share/vm/gc/cms/concurrentMarkSweepGeneration.cpp
--- a/src/share/vm/gc/cms/concurrentMarkSweepGeneration.cpp
+++ b/src/share/vm/gc/cms/concurrentMarkSweepGeneration.cpp
@@ -7365,9 +7365,16 @@
       if (oop(addr)->klass_or_null() != NULL) {
         // Ignore mark word because we are running concurrent with mutators
         assert(oop(addr)->is_oop(true), "live block should be an oop");
-        assert(size ==
+        Klass* k = oop(addr)->klass();
+
+        // It's not always safe to ask for the size of a j.l.Class object,
+        // if the Class's oop_size hasn't been set yet.
+        if (!k->is_instance_klass() ||
+            !InstanceKlass::cast(k)->is_mirror_instance_klass()) {
+          assert(size ==
                CompactibleFreeListSpace::adjustObjectSize(oop(addr)->size()),
                "P-mark and computed size do not agree");
+        }
       }
 #endif
 
diff --git a/src/share/vm/oops/oop.inline.hpp b/src/share/vm/oops/oop.inline.hpp
--- a/src/share/vm/oops/oop.inline.hpp
+++ b/src/share/vm/oops/oop.inline.hpp
@@ -258,8 +258,8 @@
     }
   }
 
-  assert(s % MinObjAlignment == 0, "alignment check");
-  assert(s > 0, "Bad size calculated");
+  assert(s % MinObjAlignment == 0, "alignment check of %d", s);
+  assert(s > 0, "Bad size calculated: %d", s);
   return s;
 }