1 /*
2 * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "oops/arrayOop.hpp"
27
28 #ifndef PRODUCT
29
30 #include "utilities/globalDefinitions.hpp"
31 // Unit tests
32
33 bool arrayOopDesc::check_overflow(BasicType type) {
34 int32_t length = max_array_length(type);
35 size_t bytes_per_element = type2aelembytes(type);
36 size_t bytes = (size_t)length * bytes_per_element + header_size_in_bytes();
37 return (bytes - header_size_in_bytes()) / bytes_per_element == (size_t)length;
38 }
39
40 // The old implementation of max_array_length. For 64-bit platforms the old
41 // and new implementations should return the same value.
42 int32_t arrayOopDesc::old_max_array_length(BasicType type) {
43 const int bytes_per_element = type2aelembytes(type);
44 if (bytes_per_element < HeapWordSize) {
45 return max_jint;
46 }
47 const int32_t max_words = align_size_down(max_jint, MinObjAlignment);
48 const int32_t max_element_words = max_words - header_size(type);
49 const int32_t words_per_element = bytes_per_element >> LogHeapWordSize;
50 return max_element_words / words_per_element;
51 }
52
53 bool arrayOopDesc::test_max_array_length() {
54 tty->print_cr("test_max_array_length");
55
56 assert(check_overflow(T_BOOLEAN), "size_t overflow for boolean array");
57 assert(check_overflow(T_CHAR), "size_t overflow for char array");
58 assert(check_overflow(T_FLOAT), "size_t overflow for float array");
59 assert(check_overflow(T_DOUBLE), "size_t overflow for double array");
60 assert(check_overflow(T_BYTE), "size_t overflow for byte array");
61 assert(check_overflow(T_SHORT), "size_t overflow for short array");
62 assert(check_overflow(T_INT), "size_t overflow for int array");
63 assert(check_overflow(T_LONG), "size_t overflow for long array");
64 assert(check_overflow(T_OBJECT), "size_t overflow for object array");
65 assert(check_overflow(T_ARRAY), "size_t overflow for array array");
66 assert(check_overflow(T_NARROWOOP), "size_t overflow for narrowOop array");
67
68 // T_VOID and T_ADDRESS are not supported by max_array_length()
69
70 #ifdef _LP64
71 assert(max_array_length(T_BOOLEAN) == old_max_array_length(T_BOOLEAN), "calculation changed for boolean");
72 assert(max_array_length(T_CHAR) == old_max_array_length(T_CHAR), "calculation changed for char");
73 assert(max_array_length(T_FLOAT) == old_max_array_length(T_FLOAT), "calculation changed for float");
74 assert(max_array_length(T_DOUBLE) == old_max_array_length(T_DOUBLE), "calculation changed for double");
75 assert(max_array_length(T_BYTE) == old_max_array_length(T_BYTE), "calculation changed for byte");
76 assert(max_array_length(T_SHORT) == old_max_array_length(T_SHORT), "calculation changed for short");
77 assert(max_array_length(T_INT) == old_max_array_length(T_INT), "calculation changed for int");
78 assert(max_array_length(T_LONG) == old_max_array_length(T_LONG), "calculation changed for long");
79 assert(max_array_length(T_OBJECT) == old_max_array_length(T_OBJECT), "calculation changed for object");
80 assert(max_array_length(T_ARRAY) == old_max_array_length(T_ARRAY), "calculation changed for array");
81 assert(max_array_length(T_NARROWOOP) == old_max_array_length(T_NARROWOOP), "calculation changed for narrowOop");
82 #endif
83
84 return true;
85 }
86
87
88 #endif //PRODUCT