1 /*
2 * Copyright (c) 2009, 2017, 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
32 template <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
41 template <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
52 template <class E, MEMFLAGS F>
53 Stack<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
59 template <class E, MEMFLAGS F>
60 void 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
70 template <class E, MEMFLAGS F>
71 E 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
82 template <class E, MEMFLAGS F>
83 void 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
90 template <class E, MEMFLAGS F>
91 size_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
102 template <class E, MEMFLAGS F>
103 size_t Stack<E, F>::link_offset() const
104 {
105 return align_up(this->_seg_size * sizeof(E), sizeof(E*));
106 }
107
108 template <class E, MEMFLAGS F>
109 size_t Stack<E, F>::segment_bytes() const
110 {
111 return link_offset() + sizeof(E*);
112 }
113
114 template <class E, MEMFLAGS F>
115 E** Stack<E, F>::link_addr(E* seg) const
116 {
117 return (E**) ((char*)seg + link_offset());
118 }
119
120 template <class E, MEMFLAGS F>
121 E* Stack<E, F>::get_link(E* seg) const
122 {
123 return *link_addr(seg);
124 }
125
126 template <class E, MEMFLAGS F>
127 E* 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
133 template <class E, MEMFLAGS F>
134 E* Stack<E, F>::alloc(size_t bytes)
135 {
136 return (E*) NEW_C_HEAP_ARRAY(char, bytes, F);
137 }
138
139 template <class E, MEMFLAGS F>
140 void 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.
150 template <class E, MEMFLAGS F>
151 NOINLINE 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
171 template <class E, MEMFLAGS F>
172 void 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
192 template <class E, MEMFLAGS F>
193 void 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
203 template <class E, MEMFLAGS F>
204 void 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
216 template <class E, MEMFLAGS F>
217 void 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
232 template <class E, MEMFLAGS F>
233 void 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
241 template <class E, MEMFLAGS F>
242 E* ResourceStack<E, F>::alloc(size_t bytes)
243 {
244 return (E*) resource_allocate_bytes(bytes);
245 }
246
247 template <class E, MEMFLAGS F>
248 void ResourceStack<E, F>::free(E* addr, size_t bytes)
249 {
250 resource_free_bytes((char*) addr, bytes);
251 }
252
253 template <class E, MEMFLAGS F>
254 void 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
261 template <class E, MEMFLAGS F>
262 E* 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