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/stack.hpp"
29
30 template <MEMFLAGS F> StackBase<F>::StackBase(size_t segment_size, size_t max_cache_size,
31 size_t max_size):
32 _seg_size(segment_size),
33 _max_cache_size(max_cache_size),
34 _max_size(adjust_max_size(max_size, segment_size))
35 {
36 assert(_max_size % _seg_size == 0, "not a multiple");
37 }
38
39 template <MEMFLAGS F> size_t StackBase<F>::adjust_max_size(size_t max_size, size_t seg_size)
40 {
41 assert(seg_size > 0, "cannot be 0");
42 assert(max_size >= seg_size || max_size == 0, "max_size too small");
43 const size_t limit = max_uintx - (seg_size - 1);
44 if (max_size == 0 || max_size > limit) {
45 max_size = limit;
46 }
47 return (max_size + seg_size - 1) / seg_size * seg_size;
48 }
49
50 template <class E, MEMFLAGS F>
51 Stack<E, F>::Stack(size_t segment_size, size_t max_cache_size, size_t max_size):
52 StackBase<F>(adjust_segment_size(segment_size), max_cache_size, max_size)
53 {
54 reset(true);
55 }
56
57 template <class E, MEMFLAGS F>
58 void Stack<E, F>::push(E item)
59 {
60 assert(!is_full(), "pushing onto a full stack");
61 if (this->_cur_seg_size == this->_seg_size) {
62 push_segment();
63 }
64 this->_cur_seg[this->_cur_seg_size] = item;
65 ++this->_cur_seg_size;
66 }
67
68 template <class E, MEMFLAGS F>
69 E Stack<E, F>::pop()
70 {
71 assert(!is_empty(), "popping from an empty stack");
72 if (this->_cur_seg_size == 1) {
73 E tmp = _cur_seg[--this->_cur_seg_size];
74 pop_segment();
75 return tmp;
76 }
77 return this->_cur_seg[--this->_cur_seg_size];
78 }
79
80 template <class E, MEMFLAGS F>
81 void Stack<E, F>::clear(bool clear_cache)
82 {
83 free_segments(_cur_seg);
84 if (clear_cache) free_segments(_cache);
85 reset(clear_cache);
86 }
87
88 template <class E, MEMFLAGS F>
89 size_t Stack<E, F>::adjust_segment_size(size_t seg_size)
90 {
91 const size_t elem_sz = sizeof(E);
92 const size_t ptr_sz = sizeof(E*);
93 assert(elem_sz % ptr_sz == 0 || ptr_sz % elem_sz == 0, "bad element size");
94 if (elem_sz < ptr_sz) {
95 return align_up(seg_size * elem_sz, ptr_sz) / elem_sz;
96 }
97 return seg_size;
98 }
99
100 template <class E, MEMFLAGS F>
101 size_t Stack<E, F>::link_offset() const
102 {
103 return align_up(this->_seg_size * sizeof(E), sizeof(E*));
104 }
105
106 template <class E, MEMFLAGS F>
107 size_t Stack<E, F>::segment_bytes() const
108 {
109 return link_offset() + sizeof(E*);
110 }
111
112 template <class E, MEMFLAGS F>
113 E** Stack<E, F>::link_addr(E* seg) const
114 {
115 return (E**) ((char*)seg + link_offset());
116 }
117
118 template <class E, MEMFLAGS F>
119 E* Stack<E, F>::get_link(E* seg) const
120 {
121 return *link_addr(seg);
122 }
123
124 template <class E, MEMFLAGS F>
125 E* Stack<E, F>::set_link(E* new_seg, E* old_seg)
126 {
127 *link_addr(new_seg) = old_seg;
128 return new_seg;
129 }
130
131 template <class E, MEMFLAGS F>
132 E* Stack<E, F>::alloc(size_t bytes)
133 {
134 return (E*) NEW_C_HEAP_ARRAY(char, bytes, F);
135 }
136
137 template <class E, MEMFLAGS F>
138 void Stack<E, F>::free(E* addr, size_t bytes)
139 {
140 FREE_C_HEAP_ARRAY(char, (char*) addr);
141 }
142
143 // Stack is used by the GC code and in some hot paths a lot of the Stack
144 // code gets inlined. This is generally good, but when too much code has
145 // been inlined, no further inlining is allowed by GCC. Therefore we need
146 // to prevent parts of the slow path in Stack to be inlined to allow other
147 // code to be.
148 template <class E, MEMFLAGS F>
149 NOINLINE void Stack<E, F>::push_segment()
150 {
151 assert(this->_cur_seg_size == this->_seg_size, "current segment is not full");
152 E* next;
153 if (this->_cache_size > 0) {
154 // Use a cached segment.
155 next = _cache;
156 _cache = get_link(_cache);
157 --this->_cache_size;
158 } else {
159 next = alloc(segment_bytes());
160 DEBUG_ONLY(zap_segment(next, true);)
161 }
162 const bool at_empty_transition = is_empty();
163 this->_cur_seg = set_link(next, _cur_seg);
164 this->_cur_seg_size = 0;
165 this->_full_seg_size += at_empty_transition ? 0 : this->_seg_size;
166 DEBUG_ONLY(verify(at_empty_transition);)
167 }
168
169 template <class E, MEMFLAGS F>
170 void Stack<E, F>::pop_segment()
171 {
172 assert(this->_cur_seg_size == 0, "current segment is not empty");
173 E* const prev = get_link(_cur_seg);
174 if (this->_cache_size < this->_max_cache_size) {
175 // Add the current segment to the cache.
176 DEBUG_ONLY(zap_segment(_cur_seg, false);)
177 _cache = set_link(_cur_seg, _cache);
178 ++this->_cache_size;
179 } else {
180 DEBUG_ONLY(zap_segment(_cur_seg, true);)
181 free(_cur_seg, segment_bytes());
182 }
183 const bool at_empty_transition = prev == NULL;
184 this->_cur_seg = prev;
185 this->_cur_seg_size = this->_seg_size;
186 this->_full_seg_size -= at_empty_transition ? 0 : this->_seg_size;
187 DEBUG_ONLY(verify(at_empty_transition);)
188 }
189
190 template <class E, MEMFLAGS F>
191 void Stack<E, F>::free_segments(E* seg)
192 {
193 const size_t bytes = segment_bytes();
194 while (seg != NULL) {
195 E* const prev = get_link(seg);
196 free(seg, bytes);
197 seg = prev;
198 }
199 }
200
201 template <class E, MEMFLAGS F>
202 void Stack<E, F>::reset(bool reset_cache)
203 {
204 this->_cur_seg_size = this->_seg_size; // So push() will alloc a new segment.
205 this->_full_seg_size = 0;
206 _cur_seg = NULL;
207 if (reset_cache) {
208 this->_cache_size = 0;
209 _cache = NULL;
210 }
211 }
212
213 #ifdef ASSERT
214 template <class E, MEMFLAGS F>
215 void Stack<E, F>::verify(bool at_empty_transition) const
216 {
217 assert(size() <= this->max_size(), "stack exceeded bounds");
218 assert(this->cache_size() <= this->max_cache_size(), "cache exceeded bounds");
219 assert(this->_cur_seg_size <= this->segment_size(), "segment index exceeded bounds");
220
221 assert(this->_full_seg_size % this->_seg_size == 0, "not a multiple");
222 assert(at_empty_transition || is_empty() == (size() == 0), "mismatch");
223 assert((_cache == NULL) == (this->cache_size() == 0), "mismatch");
224
225 if (is_empty()) {
226 assert(this->_cur_seg_size == this->segment_size(), "sanity");
227 }
228 }
229
230 template <class E, MEMFLAGS F>
231 void Stack<E, F>::zap_segment(E* seg, bool zap_link_field) const
232 {
233 if (!ZapStackSegments) return;
234 const size_t zap_bytes = segment_bytes() - (zap_link_field ? 0 : sizeof(E*));
235 uint32_t* cur = (uint32_t*)seg;
236 const uint32_t* end = cur + zap_bytes / sizeof(uint32_t);
237 while (cur < end) {
238 *cur++ = 0xfadfaded;
239 }
240 }
241 #endif
242
243 template <class E, MEMFLAGS F>
244 E* ResourceStack<E, F>::alloc(size_t bytes)
245 {
246 return (E*) resource_allocate_bytes(bytes);
247 }
248
249 template <class E, MEMFLAGS F>
250 void ResourceStack<E, F>::free(E* addr, size_t bytes)
251 {
252 resource_free_bytes((char*) addr, bytes);
253 }
254
255 template <class E, MEMFLAGS F>
256 void StackIterator<E, F>::sync()
257 {
258 _full_seg_size = _stack._full_seg_size;
259 _cur_seg_size = _stack._cur_seg_size;
260 _cur_seg = _stack._cur_seg;
261 }
262
263 template <class E, MEMFLAGS F>
264 E* StackIterator<E, F>::next_addr()
265 {
266 assert(!is_empty(), "no items left");
267 if (_cur_seg_size == 1) {
268 E* addr = _cur_seg;
269 _cur_seg = _stack.get_link(_cur_seg);
270 _cur_seg_size = _stack.segment_size();
271 _full_seg_size -= _stack.segment_size();
272 return addr;
273 }
274 return _cur_seg + --_cur_seg_size;
275 }
276
277 #endif // SHARE_VM_UTILITIES_STACK_INLINE_HPP