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48 lines
1.8 KiB
C++
48 lines
1.8 KiB
C++
/*
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* Copyright (c) 2023, Red Hat, Inc. All rights reserved.
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* Copyright (c) 2023, 2025, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*
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*/
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#include "oops/compressedKlass.hpp"
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#include "utilities/globalDefinitions.hpp"
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char* CompressedKlassPointers::reserve_address_space_for_compressed_classes(size_t size, bool aslr, bool optimize_for_zero_base) {
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char* result = nullptr;
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// Optimize for base=0 shift=0; failing that, for base=0 shift>0
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if (optimize_for_zero_base) {
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result = reserve_address_space_for_unscaled_encoding(size, aslr);
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if (result == nullptr) {
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result = reserve_address_space_for_zerobased_encoding(size, aslr);
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}
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}
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// Optimize for a single 16-bit move: a base that has only bits set in its third quadrant [32..48).
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if (result == nullptr) {
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result = reserve_address_space_for_16bit_move(size, aslr);
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}
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return result;
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}
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