1.1 --- a/src/share/vm/oops/arrayOop.hpp Fri Oct 28 13:04:10 2011 -0400
1.2 +++ b/src/share/vm/oops/arrayOop.hpp Mon Oct 31 08:01:20 2011 +0100
1.3 @@ -1,5 +1,5 @@
1.4 /*
1.5 - * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
1.6 + * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
1.7 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.8 *
1.9 * This code is free software; you can redistribute it and/or modify it
1.10 @@ -104,20 +104,26 @@
1.11
1.12 // Return the maximum length of an array of BasicType. The length can passed
1.13 // to typeArrayOop::object_size(scale, length, header_size) without causing an
1.14 - // overflow.
1.15 + // overflow. We also need to make sure that this will not overflow a size_t on
1.16 + // 32 bit platforms when we convert it to a byte size.
1.17 static int32_t max_array_length(BasicType type) {
1.18 assert(type >= 0 && type < T_CONFLICT, "wrong type");
1.19 assert(type2aelembytes(type) != 0, "wrong type");
1.20 - const int bytes_per_element = type2aelembytes(type);
1.21 - if (bytes_per_element < HeapWordSize) {
1.22 +
1.23 + const size_t max_element_words_per_size_t = align_size_down((SIZE_MAX/HeapWordSize - header_size(type)), MinObjAlignment);
1.24 + const size_t max_elements_per_size_t = HeapWordSize * max_element_words_per_size_t / type2aelembytes(type);
1.25 + if ((size_t)max_jint < max_elements_per_size_t) {
1.26 return max_jint;
1.27 }
1.28 + return (int32_t)max_elements_per_size_t;
1.29 + }
1.30
1.31 - const int32_t max_words = align_size_down(max_jint, MinObjAlignment);
1.32 - const int32_t max_element_words = max_words - header_size(type);
1.33 - const int32_t words_per_element = bytes_per_element >> LogHeapWordSize;
1.34 - return max_element_words / words_per_element;
1.35 - }
1.36 +// for unit testing
1.37 +#ifndef PRODUCT
1.38 + static bool check_max_length_overflow(BasicType type);
1.39 + static int32_t old_max_array_length(BasicType type);
1.40 + static bool test_max_array_length();
1.41 +#endif
1.42 };
1.43
1.44 #endif // SHARE_VM_OOPS_ARRAYOOP_HPP
