test/hotspot/gtest/oops/test_objArrayOop.cpp

*** 1,7 ***
--- 1,8 ---
  /*
   * Copyright Amazon.com Inc. or its affiliates. All rights reserved.
+  * Copyright (c) 2026, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.

*** 20,18 ***
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  #include "oops/objArrayOop.hpp"
  #include "unittest.hpp"
  #include "utilities/globalDefinitions.hpp"
  
! TEST_VM(objArrayOop, osize) {
!   static const struct {
!     int objal; bool coops; bool coh; int result;
!   } x[] = {
! //    ObjAligInB, UseCoops, UseCOH, object size in heap words
  #ifdef _LP64
      { 8,          false, false,   3 },  // 16 byte header, 8 byte oops
      { 8,          true,  false,   3 },  // 16 byte header, 4 byte oops
      { 8,          false, true,    3 },  // 12 byte header, 8 byte oops
      { 8,          true,  true,    2 },  // 12 byte header, 4 byte oops
--- 21,24 ---
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  #include "oops/objArrayOop.hpp"
+ #include "oops/refArrayOop.hpp"
+ #include "oops/flatArrayOop.hpp"
  #include "unittest.hpp"
  #include "utilities/globalDefinitions.hpp"
  
! TEST_VM(objArrayOop, osize_refarray) {
!   struct ObjArrayStruct {
!     int objal;  // Object alignment in bytes
!     bool coops; // UseCompressedOops
!     bool coh;   // UseCompactObjectHeaders
+     int result; // Expected size in heap words
+   };
+ 
+   static const ObjArrayStruct refCases[] = {
  #ifdef _LP64
      { 8,          false, false,   3 },  // 16 byte header, 8 byte oops
      { 8,          true,  false,   3 },  // 16 byte header, 4 byte oops
      { 8,          false, true,    3 },  // 12 byte header, 8 byte oops
      { 8,          true,  true,    2 },  // 12 byte header, 4 byte oops

*** 44,14 ***
      { 256,        false, true,   32 }, // 12 byte header, 8 byte oops, 256-byte align
      { 256,        true,  true,   32 }, // 12 byte header, 4 byte oops, 256-byte align
  #else
      { 8,          false, false,   4 }, // 12 byte header, 4 byte oops, wordsize 4
  #endif
-     { -1,         false, false,  -1 }
    };
!   for (int i = 0; x[i].result != -1; i++) {
!     if (x[i].objal == (int)ObjectAlignmentInBytes && x[i].coops == UseCompressedOops &&
!         x[i].coh == UseCompactObjectHeaders) {
!       EXPECT_EQ(objArrayOopDesc::object_size(1), (size_t)x[i].result);
      }
    }
  }
--- 51,54 ---
      { 256,        false, true,   32 }, // 12 byte header, 8 byte oops, 256-byte align
      { 256,        true,  true,   32 }, // 12 byte header, 4 byte oops, 256-byte align
  #else
      { 8,          false, false,   4 }, // 12 byte header, 4 byte oops, wordsize 4
  #endif
    };
! 
!   for (const ObjArrayStruct c : refCases) {
!     if (c.objal == (int)ObjectAlignmentInBytes && c.coops == UseCompressedOops &&
!         c.coh == UseCompactObjectHeaders) {
+       EXPECT_EQ(refArrayOopDesc::object_size(1), (size_t)c.result);
+     }
+   }
+ }
+ 
+ static int make_flat_array_layout_helper(int payload_size_bytes, bool null_free) {
+   BasicType etype = T_FLAT_ELEMENT;
+   int esize = log2i_exact(round_up_power_of_2(payload_size_bytes));
+   int hsize = arrayOopDesc::base_offset_in_bytes(etype);
+   return Klass::array_layout_helper(Klass::_lh_array_tag_flat_value, null_free, hsize, etype, esize);
+ }
+ 
+ TEST_VM(objArrayOop, osize_flatarray) {
+   struct FlatArraySizeCase {
+     int objal;        // Object alignment in bytes
+     int payload_size; // Raw inline payload size
+     bool null_free;   // Null free
+     int result;       // Expected size in heap words
+   };
+ 
+   static const FlatArraySizeCase flatCases[] = {
+ #ifdef _LP64
+  {8,   4, false, 3},
+  {8,   8, false, 3},
+  {8,   4, true,  3},
+  {8,   8, true,  3},
+  {16,  4, false, 4},
+  {16,  8, false, 4},
+  {16,  4, true,  4},
+  {16,  8, true,  4},
+  {256, 4, false, 32},
+  {256, 8, false, 32},
+  {256, 4, true,  32},
+  {256, 8, true,  32},
+ #endif
+   };
+ 
+   for (const FlatArraySizeCase c : flatCases) {
+     if (c.objal == (int)ObjectAlignmentInBytes) {
+       int lh = make_flat_array_layout_helper(c.payload_size, c.null_free);
+       EXPECT_EQ(flatArrayOopDesc::object_size(lh, 1), c.result);
      }
    }
  }