# HG changeset patch
# User never
# Date 1324332983 28800
# Node ID 669f6a7d5b70bc6338eb0331a985de813dffb3c2
# Parent  127b3692c168219cb69c0ebf5c9c1f1b17a0f82a
7121073: secondary_super_cache memory slice has incorrect bounds in flatten_alias_type
Reviewed-by: kvn

diff -r 127b3692c168 -r 669f6a7d5b70 src/share/vm/opto/compile.cpp
--- a/src/share/vm/opto/compile.cpp	Wed Dec 14 14:54:38 2011 -0800
+++ b/src/share/vm/opto/compile.cpp	Mon Dec 19 14:16:23 2011 -0800
@@ -1282,12 +1282,11 @@
   if( tk ) {
     // If we are referencing a field within a Klass, we need
     // to assume the worst case of an Object.  Both exact and
-    // inexact types must flatten to the same alias class.
-    // Since the flattened result for a klass is defined to be
-    // precisely java.lang.Object, use a constant ptr.
+    // inexact types must flatten to the same alias class so
+    // use NotNull as the PTR.
     if ( offset == Type::OffsetBot || (offset >= 0 && (size_t)offset < sizeof(Klass)) ) {
 
-      tj = tk = TypeKlassPtr::make(TypePtr::Constant,
+      tj = tk = TypeKlassPtr::make(TypePtr::NotNull,
                                    TypeKlassPtr::OBJECT->klass(),
                                    offset);
     }
@@ -1307,10 +1306,12 @@
     // these 2 disparate memories into the same alias class.  Since the
     // primary supertype array is read-only, there's no chance of confusion
     // where we bypass an array load and an array store.
-    uint off2 = offset - Klass::primary_supers_offset_in_bytes();
-    if( offset == Type::OffsetBot ||
-        off2 < Klass::primary_super_limit()*wordSize ) {
-      offset = sizeof(oopDesc) +Klass::secondary_super_cache_offset_in_bytes();
+    int primary_supers_offset = sizeof(klassOopDesc) + Klass::primary_supers_offset_in_bytes();
+    if (offset == Type::OffsetBot ||
+        (offset >= primary_supers_offset &&
+         offset < (int)(primary_supers_offset + Klass::primary_super_limit() * wordSize)) ||
+        offset == (int)(sizeof(klassOopDesc) + Klass::secondary_super_cache_offset_in_bytes())) {
+      offset = sizeof(klassOopDesc) + Klass::secondary_super_cache_offset_in_bytes();
       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, tk->klass(), offset );
     }
   }