1/* 2 * Copyright (c) 2009, 2016, 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_UTILITIES_STACK_INLINE_HPP 26#define SHARE_VM_UTILITIES_STACK_INLINE_HPP 27 28#include "utilities/align.hpp" 29#include "utilities/stack.hpp" 30#include "utilities/copy.hpp" 31 32template <MEMFLAGS F> StackBase<F>::StackBase(size_t segment_size, size_t max_cache_size, 33 size_t max_size): 34 _seg_size(segment_size), 35 _max_cache_size(max_cache_size), 36 _max_size(adjust_max_size(max_size, segment_size)) 37{ 38 assert(_max_size % _seg_size == 0, "not a multiple"); 39} 40 41template <MEMFLAGS F> size_t StackBase<F>::adjust_max_size(size_t max_size, size_t seg_size) 42{ 43 assert(seg_size > 0, "cannot be 0"); 44 assert(max_size >= seg_size || max_size == 0, "max_size too small"); 45 const size_t limit = max_uintx - (seg_size - 1); 46 if (max_size == 0 || max_size > limit) { 47 max_size = limit; 48 } 49 return (max_size + seg_size - 1) / seg_size * seg_size; 50} 51 52template <class E, MEMFLAGS F> 53Stack<E, F>::Stack(size_t segment_size, size_t max_cache_size, size_t max_size): 54 StackBase<F>(adjust_segment_size(segment_size), max_cache_size, max_size) 55{ 56 reset(true); 57} 58 59template <class E, MEMFLAGS F> 60void Stack<E, F>::push(E item) 61{ 62 assert(!is_full(), "pushing onto a full stack"); 63 if (this->_cur_seg_size == this->_seg_size) { 64 push_segment(); 65 } 66 this->_cur_seg[this->_cur_seg_size] = item; 67 ++this->_cur_seg_size; 68} 69 70template <class E, MEMFLAGS F> 71E Stack<E, F>::pop() 72{ 73 assert(!is_empty(), "popping from an empty stack"); 74 if (this->_cur_seg_size == 1) { 75 E tmp = _cur_seg[--this->_cur_seg_size]; 76 pop_segment(); 77 return tmp; 78 } 79 return this->_cur_seg[--this->_cur_seg_size]; 80} 81 82template <class E, MEMFLAGS F> 83void Stack<E, F>::clear(bool clear_cache) 84{ 85 free_segments(_cur_seg); 86 if (clear_cache) free_segments(_cache); 87 reset(clear_cache); 88} 89 90template <class E, MEMFLAGS F> 91size_t Stack<E, F>::adjust_segment_size(size_t seg_size) 92{ 93 const size_t elem_sz = sizeof(E); 94 const size_t ptr_sz = sizeof(E*); 95 assert(elem_sz % ptr_sz == 0 || ptr_sz % elem_sz == 0, "bad element size"); 96 if (elem_sz < ptr_sz) { 97 return align_up(seg_size * elem_sz, ptr_sz) / elem_sz; 98 } 99 return seg_size; 100} 101 102template <class E, MEMFLAGS F> 103size_t Stack<E, F>::link_offset() const 104{ 105 return align_up(this->_seg_size * sizeof(E), sizeof(E*)); 106} 107 108template <class E, MEMFLAGS F> 109size_t Stack<E, F>::segment_bytes() const 110{ 111 return link_offset() + sizeof(E*); 112} 113 114template <class E, MEMFLAGS F> 115E** Stack<E, F>::link_addr(E* seg) const 116{ 117 return (E**) ((char*)seg + link_offset()); 118} 119 120template <class E, MEMFLAGS F> 121E* Stack<E, F>::get_link(E* seg) const 122{ 123 return *link_addr(seg); 124} 125 126template <class E, MEMFLAGS F> 127E* Stack<E, F>::set_link(E* new_seg, E* old_seg) 128{ 129 *link_addr(new_seg) = old_seg; 130 return new_seg; 131} 132 133template <class E, MEMFLAGS F> 134E* Stack<E, F>::alloc(size_t bytes) 135{ 136 return (E*) NEW_C_HEAP_ARRAY(char, bytes, F); 137} 138 139template <class E, MEMFLAGS F> 140void Stack<E, F>::free(E* addr, size_t bytes) 141{ 142 FREE_C_HEAP_ARRAY(char, (char*) addr); 143} 144 145// Stack is used by the GC code and in some hot paths a lot of the Stack 146// code gets inlined. This is generally good, but when too much code has 147// been inlined, no further inlining is allowed by GCC. Therefore we need 148// to prevent parts of the slow path in Stack to be inlined to allow other 149// code to be. 150template <class E, MEMFLAGS F> 151NOINLINE void Stack<E, F>::push_segment() 152{ 153 assert(this->_cur_seg_size == this->_seg_size, "current segment is not full"); 154 E* next; 155 if (this->_cache_size > 0) { 156 // Use a cached segment. 157 next = _cache; 158 _cache = get_link(_cache); 159 --this->_cache_size; 160 } else { 161 next = alloc(segment_bytes()); 162 DEBUG_ONLY(zap_segment(next, true);) 163 } 164 const bool at_empty_transition = is_empty(); 165 this->_cur_seg = set_link(next, _cur_seg); 166 this->_cur_seg_size = 0; 167 this->_full_seg_size += at_empty_transition ? 0 : this->_seg_size; 168 DEBUG_ONLY(verify(at_empty_transition);) 169} 170 171template <class E, MEMFLAGS F> 172void Stack<E, F>::pop_segment() 173{ 174 assert(this->_cur_seg_size == 0, "current segment is not empty"); 175 E* const prev = get_link(_cur_seg); 176 if (this->_cache_size < this->_max_cache_size) { 177 // Add the current segment to the cache. 178 DEBUG_ONLY(zap_segment(_cur_seg, false);) 179 _cache = set_link(_cur_seg, _cache); 180 ++this->_cache_size; 181 } else { 182 DEBUG_ONLY(zap_segment(_cur_seg, true);) 183 free(_cur_seg, segment_bytes()); 184 } 185 const bool at_empty_transition = prev == NULL; 186 this->_cur_seg = prev; 187 this->_cur_seg_size = this->_seg_size; 188 this->_full_seg_size -= at_empty_transition ? 0 : this->_seg_size; 189 DEBUG_ONLY(verify(at_empty_transition);) 190} 191 192template <class E, MEMFLAGS F> 193void Stack<E, F>::free_segments(E* seg) 194{ 195 const size_t bytes = segment_bytes(); 196 while (seg != NULL) { 197 E* const prev = get_link(seg); 198 free(seg, bytes); 199 seg = prev; 200 } 201} 202 203template <class E, MEMFLAGS F> 204void Stack<E, F>::reset(bool reset_cache) 205{ 206 this->_cur_seg_size = this->_seg_size; // So push() will alloc a new segment. 207 this->_full_seg_size = 0; 208 _cur_seg = NULL; 209 if (reset_cache) { 210 this->_cache_size = 0; 211 _cache = NULL; 212 } 213} 214 215#ifdef ASSERT 216template <class E, MEMFLAGS F> 217void Stack<E, F>::verify(bool at_empty_transition) const 218{ 219 assert(size() <= this->max_size(), "stack exceeded bounds"); 220 assert(this->cache_size() <= this->max_cache_size(), "cache exceeded bounds"); 221 assert(this->_cur_seg_size <= this->segment_size(), "segment index exceeded bounds"); 222 223 assert(this->_full_seg_size % this->_seg_size == 0, "not a multiple"); 224 assert(at_empty_transition || is_empty() == (size() == 0), "mismatch"); 225 assert((_cache == NULL) == (this->cache_size() == 0), "mismatch"); 226 227 if (is_empty()) { 228 assert(this->_cur_seg_size == this->segment_size(), "sanity"); 229 } 230} 231 232template <class E, MEMFLAGS F> 233void Stack<E, F>::zap_segment(E* seg, bool zap_link_field) const 234{ 235 if (!ZapStackSegments) return; 236 const size_t zap_bytes = segment_bytes() - (zap_link_field ? 0 : sizeof(E*)); 237 Copy::fill_to_bytes(seg, zap_bytes, badStackSegVal); 238} 239#endif 240 241template <class E, MEMFLAGS F> 242E* ResourceStack<E, F>::alloc(size_t bytes) 243{ 244 return (E*) resource_allocate_bytes(bytes); 245} 246 247template <class E, MEMFLAGS F> 248void ResourceStack<E, F>::free(E* addr, size_t bytes) 249{ 250 resource_free_bytes((char*) addr, bytes); 251} 252 253template <class E, MEMFLAGS F> 254void StackIterator<E, F>::sync() 255{ 256 _full_seg_size = _stack._full_seg_size; 257 _cur_seg_size = _stack._cur_seg_size; 258 _cur_seg = _stack._cur_seg; 259} 260 261template <class E, MEMFLAGS F> 262E* StackIterator<E, F>::next_addr() 263{ 264 assert(!is_empty(), "no items left"); 265 if (_cur_seg_size == 1) { 266 E* addr = _cur_seg; 267 _cur_seg = _stack.get_link(_cur_seg); 268 _cur_seg_size = _stack.segment_size(); 269 _full_seg_size -= _stack.segment_size(); 270 return addr; 271 } 272 return _cur_seg + --_cur_seg_size; 273} 274 275#endif // SHARE_VM_UTILITIES_STACK_INLINE_HPP 276