jdk/src/hotspot/share/oops/compressedKlass.inline.hpp
Thomas Stuefe da296cbea1 8363996: Obsolete UseCompressedClassPointers
Reviewed-by: rkennke, kvn, adinn, dholmes, mdoerr, iklam, fyang
2026-03-26 11:08:48 +00:00

109 lines
4.2 KiB
C++

/*
* Copyright (c) 2017, 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
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*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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#ifndef SHARE_OOPS_COMPRESSEDKLASS_INLINE_HPP
#define SHARE_OOPS_COMPRESSEDKLASS_INLINE_HPP
#include "oops/compressedKlass.hpp"
#include "memory/universe.hpp"
#include "oops/oop.hpp"
#include "utilities/align.hpp"
#include "utilities/globalDefinitions.hpp"
inline Klass* CompressedKlassPointers::decode_not_null_without_asserts(narrowKlass v, address narrow_base_base, int shift) {
return (Klass*)((uintptr_t)narrow_base_base +((uintptr_t)v << shift));
}
inline narrowKlass CompressedKlassPointers::encode_not_null_without_asserts(const Klass* k, address narrow_base, int shift) {
return (narrowKlass)(pointer_delta(k, narrow_base, 1) >> shift);
}
inline Klass* CompressedKlassPointers::decode_not_null_without_asserts(narrowKlass v) {
return decode_not_null_without_asserts(v, base(), shift());
}
inline Klass* CompressedKlassPointers::decode_without_asserts(narrowKlass v) {
return is_null(v) ? nullptr : decode_not_null_without_asserts(v, base(), shift());
}
inline Klass* CompressedKlassPointers::decode_not_null(narrowKlass v) {
assert(!is_null(v), "narrow klass value can never be zero");
DEBUG_ONLY(check_valid_narrow_klass_id(v);)
Klass* const k = decode_not_null_without_asserts(v, base(), shift());
DEBUG_ONLY(check_encodable(k));
return k;
}
inline Klass* CompressedKlassPointers::decode(narrowKlass v) {
return is_null(v) ? nullptr : decode_not_null(v);
}
inline narrowKlass CompressedKlassPointers::encode_not_null(const Klass* v) {
assert(!is_null(v), "klass value can never be zero");
DEBUG_ONLY(check_encodable(v);)
const narrowKlass nk = encode_not_null_without_asserts(v, base(), shift());
assert(decode_not_null_without_asserts(nk, base(), shift()) == v, "reversibility");
DEBUG_ONLY(check_valid_narrow_klass_id(nk);)
return nk;
}
inline narrowKlass CompressedKlassPointers::encode(const Klass* v) {
return is_null(v) ? (narrowKlass)0 : encode_not_null(v);
}
#ifdef ASSERT
inline void CompressedKlassPointers::check_encodable(const void* addr) {
assert(addr != nullptr, "Null Klass?");
assert(is_encodable(addr),
"Address " PTR_FORMAT " is not encodable (Klass range: " RANGEFMT ", klass alignment: %d)",
p2i(addr), RANGE2FMTARGS(_klass_range_start, _klass_range_end), klass_alignment_in_bytes());
}
inline void CompressedKlassPointers::check_valid_narrow_klass_id(narrowKlass nk) {
check_init(_base);
assert(nk > 0, "narrow Klass ID is 0");
const uint64_t nk_mask = ~right_n_bits(narrow_klass_pointer_bits());
assert(((uint64_t)nk & nk_mask) == 0, "narrow klass id bit spillover (%u)", nk);
assert(nk >= _lowest_valid_narrow_klass_id &&
nk <= _highest_valid_narrow_klass_id, "narrowKlass ID out of range (%u)", nk);
}
#endif // ASSERT
// Given a narrow Klass ID, returns true if it appears to be valid
inline bool CompressedKlassPointers::is_valid_narrow_klass_id(narrowKlass nk) {
return nk >= _lowest_valid_narrow_klass_id && nk < _highest_valid_narrow_klass_id;
}
inline address CompressedKlassPointers::encoding_range_end() {
#ifdef _LP64
const int max_bits = narrow_klass_pointer_bits() + _shift;
return (address)((uintptr_t)_base + nth_bit(max_bits));
#else
return (address)SIZE_MAX;
#endif
}
#endif // SHARE_OOPS_COMPRESSEDKLASS_INLINE_HPP