1 /*
  2  * Copyright (c) 2024, Red Hat, Inc. All rights reserved.
  3  * Copyright (c) 2024, 2025, Oracle and/or its affiliates. All rights reserved.
  4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  5  *
  6  * This code is free software; you can redistribute it and/or modify it
  7  * under the terms of the GNU General Public License version 2 only, as
  8  * published by the Free Software Foundation.
  9  *
 10  * This code is distributed in the hope that it will be useful, but WITHOUT
 11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 13  * version 2 for more details (a copy is included in the LICENSE file that
 14  * accompanied this code).
 15  *
 16  * You should have received a copy of the GNU General Public License version
 17  * 2 along with this work; if not, write to the Free Software Foundation,
 18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 19  *
 20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 21  * or visit www.oracle.com if you need additional information or have any
 22  * questions.
 23  */
 24 
 25 #include "oops/compressedKlass.inline.hpp"
 26 #include "utilities/globalDefinitions.hpp"
 27 
 28 #include "unittest.hpp"
 29 
 30 TEST_VM(CompressedKlass, basics) {
 31   if (!UseCompressedClassPointers) {
 32     return;
 33   }
 34   ASSERT_LE((address)0, CompressedKlassPointers::base());
 35   ASSERT_LE(CompressedKlassPointers::base(), CompressedKlassPointers::klass_range_start());
 36   ASSERT_LT(CompressedKlassPointers::klass_range_start(), CompressedKlassPointers::klass_range_end());
 37   ASSERT_LE(CompressedKlassPointers::klass_range_end(), CompressedKlassPointers::encoding_range_end());
 38 
 39   switch (CompressedKlassPointers::shift()) {
 40   case 0:
 41     ASSERT_EQ(CompressedKlassPointers::encoding_range_end() - CompressedKlassPointers::base(), (ptrdiff_t)(4 * G));
 42     break;
 43   case 3:
 44     ASSERT_EQ(CompressedKlassPointers::encoding_range_end() - CompressedKlassPointers::base(), (ptrdiff_t)(32 * G));
 45     break;
 46   default:
 47     const size_t expected_size = nth_bit(CompressedKlassPointers::narrow_klass_pointer_bits() + CompressedKlassPointers::shift());
 48     ASSERT_EQ(CompressedKlassPointers::encoding_range_end() - CompressedKlassPointers::base(), (ptrdiff_t)expected_size);
 49   }
 50 }
 51 
 52 TEST_VM(CompressedKlass, ccp_off) {
 53   if (UseCompressedClassPointers) {
 54     return;
 55   }
 56   ASSERT_EQ(CompressedKlassPointers::klass_range_start(), (address)nullptr);
 57   ASSERT_EQ(CompressedKlassPointers::klass_range_end(), (address)nullptr);
 58   // We should be able to call CompressedKlassPointers::is_encodable, and it should
 59   // always return false
 60   ASSERT_FALSE(CompressedKlassPointers::is_encodable((address)0x12345));
 61 }
 62 
 63 
 64 TEST_VM(CompressedKlass, test_too_low_address) {
 65   if (!UseCompressedClassPointers) {
 66     return;
 67   }
 68   address really_low = (address) 32;
 69   ASSERT_FALSE(CompressedKlassPointers::is_encodable(really_low));
 70   address low = CompressedKlassPointers::klass_range_start() - 1;
 71   ASSERT_FALSE(CompressedKlassPointers::is_encodable(low));
 72 }
 73 
 74 TEST_VM(CompressedKlass, test_too_high_address) {
 75   if (!UseCompressedClassPointers) {
 76     return;
 77   }
 78   address really_high = (address) UINTPTR_MAX;
 79   ASSERT_FALSE(CompressedKlassPointers::is_encodable(really_high));
 80   address high = CompressedKlassPointers::klass_range_end();
 81   ASSERT_FALSE(CompressedKlassPointers::is_encodable(high));
 82 }
 83 
 84 TEST_VM(CompressedKlass, test_unaligned_address) {
 85   if (!UseCompressedClassPointers) {
 86     return;
 87   }
 88   const size_t alignment = CompressedKlassPointers::klass_alignment_in_bytes();
 89   address addr = CompressedKlassPointers::klass_range_start() + alignment - 1;
 90   ASSERT_FALSE(CompressedKlassPointers::is_encodable(addr));
 91   // Try word-aligned, but not sufficiently aligned
 92   if (alignment > BytesPerWord) {
 93     addr = CompressedKlassPointers::klass_range_start() + BytesPerWord;
 94     ASSERT_FALSE(CompressedKlassPointers::is_encodable(addr));
 95   }
 96   addr = CompressedKlassPointers::klass_range_end() - 1;
 97   ASSERT_FALSE(CompressedKlassPointers::is_encodable(addr));
 98 }
 99 
100 TEST_VM(CompressedKlass, test_good_address) {
101   if (!UseCompressedClassPointers) {
102     return;
103   }
104   const size_t alignment = CompressedKlassPointers::klass_alignment_in_bytes();
105   address addr = CompressedKlassPointers::klass_range_start();
106   ASSERT_TRUE(CompressedKlassPointers::is_encodable(addr));
107   addr = CompressedKlassPointers::klass_range_end() - alignment;
108   ASSERT_TRUE(CompressedKlassPointers::is_encodable(addr));
109 }