8338260: [lworld] assert(elements_end <= obj_end) failed: payload mus…

…t fit in object

Reviewed-by: thartmann, fparain

src/hotspot/share/oops/arrayOop.hpp

@@ -26,6 +26,7 @@
 #define SHARE_OOPS_ARRAYOOP_HPP
 
 #include "oops/oop.hpp"
+#include "runtime/globals.hpp"
 #include "utilities/align.hpp"
 #include "utilities/globalDefinitions.hpp"
 
@@ -55,12 +56,15 @@ class arrayOopDesc : public oopDesc {
 
   // Given a type, return true if elements of that type must be aligned to 64-bit.
   static bool element_type_should_be_aligned(BasicType type) {
+    if (EnableValhalla && type == T_PRIMITIVE_OBJECT) {
+      return true; //CMH: tighten the alignment when removing T_PRIMITIVE_OBJECT
+    }
 #ifdef _LP64
-    if (type == T_OBJECT || type == T_ARRAY || type == T_PRIMITIVE_OBJECT) {
+    if (type == T_OBJECT || type == T_ARRAY) {
       return !UseCompressedOops;
     }
 #endif
-    return type == T_DOUBLE || type == T_LONG || type == T_PRIMITIVE_OBJECT;
+    return type == T_DOUBLE || type == T_LONG;
   }
 
  public:

src/hotspot/share/oops/flatArrayOop.hpp

@@ -50,7 +50,8 @@ class flatArrayOopDesc : public arrayOopDesc {
   }
 
   static int object_size(int lh, int length) {
-    julong size_in_bytes = header_size_in_bytes() + element_size(lh, length);
+    julong size_in_bytes = base_offset_in_bytes(Klass::layout_helper_element_type(lh));
+    size_in_bytes += element_size(lh, length);
     julong size_in_words = ((size_in_bytes + (HeapWordSize-1)) >> LogHeapWordSize);
     assert(size_in_words <= (julong)max_jint, "no overflow");
     return align_object_size((intptr_t)size_in_words);