1 /* 2 * Copyright (c) 2013, 2015, 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 #ifndef SHARE_VM_GC_G1_G1BIASEDARRAY_HPP 26 #define SHARE_VM_GC_G1_G1BIASEDARRAY_HPP 27 28 #include "memory/allocation.hpp" 29 #include "memory/memRegion.hpp" 30 #include "utilities/debug.hpp" 31 32 // Implements the common base functionality for arrays that contain provisions 33 // for accessing its elements using a biased index. 34 // The element type is defined by the instantiating the template. 35 class G1BiasedMappedArrayBase VALUE_OBJ_CLASS_SPEC { 36 friend class VMStructs; 37 public: 38 typedef size_t idx_t; 39 protected: 40 address _base; // the real base address 41 size_t _length; // the length of the array 42 address _biased_base; // base address biased by "bias" elements 43 size_t _bias; // the bias, i.e. the offset biased_base is located to the right in elements 44 uint _shift_by; // the amount of bits to shift right when mapping to an index of the array. 45 46 protected: 47 48 G1BiasedMappedArrayBase() : _base(NULL), _length(0), _biased_base(NULL), 49 _bias(0), _shift_by(0) { } 50 51 // Allocate a new array, generic version. 52 static address create_new_base_array(size_t length, size_t elem_size); 53 54 // Initialize the members of this class. The biased start address of this array 55 // is the bias (in elements) multiplied by the element size. 56 void initialize_base(address base, size_t length, size_t bias, size_t elem_size, uint shift_by) { 57 assert(base != NULL, "just checking"); 58 assert(length > 0, "just checking"); 59 assert(shift_by < sizeof(uintptr_t) * 8, err_msg("Shifting by %u, larger than word size?", shift_by)); 60 _base = base; 61 _length = length; 62 _biased_base = base - (bias * elem_size); 63 _bias = bias; 64 _shift_by = shift_by; 65 } 66 67 // Allocate and initialize this array to cover the heap addresses in the range 68 // of [bottom, end). 69 void initialize(HeapWord* bottom, HeapWord* end, size_t target_elem_size_in_bytes, size_t mapping_granularity_in_bytes) { 70 assert(mapping_granularity_in_bytes > 0, "just checking"); 71 assert(is_power_of_2(mapping_granularity_in_bytes), 72 err_msg("mapping granularity must be power of 2, is %zd", mapping_granularity_in_bytes)); 73 assert((uintptr_t)bottom % mapping_granularity_in_bytes == 0, 74 err_msg("bottom mapping area address must be a multiple of mapping granularity %zd, is " PTR_FORMAT, 75 mapping_granularity_in_bytes, p2i(bottom))); 76 assert((uintptr_t)end % mapping_granularity_in_bytes == 0, 77 err_msg("end mapping area address must be a multiple of mapping granularity %zd, is " PTR_FORMAT, 78 mapping_granularity_in_bytes, p2i(end))); 79 size_t num_target_elems = pointer_delta(end, bottom, mapping_granularity_in_bytes); 80 idx_t bias = (uintptr_t)bottom / mapping_granularity_in_bytes; 81 address base = create_new_base_array(num_target_elems, target_elem_size_in_bytes); 82 initialize_base(base, num_target_elems, bias, target_elem_size_in_bytes, log2_intptr(mapping_granularity_in_bytes)); 83 } 84 85 size_t bias() const { return _bias; } 86 uint shift_by() const { return _shift_by; } 87 88 void verify_index(idx_t index) const PRODUCT_RETURN; 89 void verify_biased_index(idx_t biased_index) const PRODUCT_RETURN; 90 void verify_biased_index_inclusive_end(idx_t biased_index) const PRODUCT_RETURN; 91 92 public: 93 // Return the length of the array in elements. 94 size_t length() const { return _length; } 95 }; 96 97 // Array that provides biased access and mapping from (valid) addresses in the 98 // heap into this array. 99 template<class T> 100 class G1BiasedMappedArray : public G1BiasedMappedArrayBase { 101 public: 102 typedef G1BiasedMappedArrayBase::idx_t idx_t; 103 104 T* base() const { return (T*)G1BiasedMappedArrayBase::_base; } 105 // Return the element of the given array at the given index. Assume 106 // the index is valid. This is a convenience method that does sanity 107 // checking on the index. 108 T get_by_index(idx_t index) const { 109 verify_index(index); 110 return this->base()[index]; 111 } 112 113 // Set the element of the given array at the given index to the 114 // given value. Assume the index is valid. This is a convenience 115 // method that does sanity checking on the index. 116 void set_by_index(idx_t index, T value) { 117 verify_index(index); 118 this->base()[index] = value; 119 } 120 121 // The raw biased base pointer. 122 T* biased_base() const { return (T*)G1BiasedMappedArrayBase::_biased_base; } 123 124 // Return the element of the given array that covers the given word in the 125 // heap. Assumes the index is valid. 126 T get_by_address(HeapWord* value) const { 127 idx_t biased_index = ((uintptr_t)value) >> this->shift_by(); 128 this->verify_biased_index(biased_index); 129 return biased_base()[biased_index]; 130 } 131 132 // Return the index of the element of the given array that covers the given 133 // word in the heap. 134 idx_t get_index_by_address(HeapWord* value) const { 135 idx_t biased_index = ((uintptr_t)value) >> this->shift_by(); 136 this->verify_biased_index(biased_index); 137 return biased_index - _bias; 138 } 139 140 // Set the value of the array entry that corresponds to the given array. 141 void set_by_address(HeapWord * address, T value) { 142 idx_t biased_index = ((uintptr_t)address) >> this->shift_by(); 143 this->verify_biased_index(biased_index); 144 biased_base()[biased_index] = value; 145 } 146 147 // Set the value of all array entries that correspond to addresses 148 // in the specified MemRegion. 149 void set_by_address(MemRegion range, T value) { 150 idx_t biased_start = ((uintptr_t)range.start()) >> this->shift_by(); 151 idx_t biased_last = ((uintptr_t)range.last()) >> this->shift_by(); 152 this->verify_biased_index(biased_start); 153 this->verify_biased_index(biased_last); 154 for (idx_t i = biased_start; i <= biased_last; i++) { 155 biased_base()[i] = value; 156 } 157 } 158 159 protected: 160 // Returns the address of the element the given address maps to 161 T* address_mapped_to(HeapWord* address) { 162 idx_t biased_index = ((uintptr_t)address) >> this->shift_by(); 163 this->verify_biased_index_inclusive_end(biased_index); 164 return biased_base() + biased_index; 165 } 166 167 public: 168 // Return the smallest address (inclusive) in the heap that this array covers. 169 HeapWord* bottom_address_mapped() const { 170 return (HeapWord*) ((uintptr_t)this->bias() << this->shift_by()); 171 } 172 173 // Return the highest address (exclusive) in the heap that this array covers. 174 HeapWord* end_address_mapped() const { 175 return (HeapWord*) ((uintptr_t)(this->bias() + this->length()) << this->shift_by()); 176 } 177 178 protected: 179 virtual T default_value() const = 0; 180 // Set all elements of the given array to the given value. 181 void clear() { 182 T value = default_value(); 183 for (idx_t i = 0; i < length(); i++) { 184 set_by_index(i, value); 185 } 186 } 187 public: 188 G1BiasedMappedArray() {} 189 190 // Allocate and initialize this array to cover the heap addresses in the range 191 // of [bottom, end). 192 void initialize(HeapWord* bottom, HeapWord* end, size_t mapping_granularity) { 193 G1BiasedMappedArrayBase::initialize(bottom, end, sizeof(T), mapping_granularity); 194 this->clear(); 195 } 196 }; 197 198 #endif // SHARE_VM_GC_G1_G1BIASEDARRAY_HPP