1 /*
2 * Copyright (c) 2009, 2014, 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 // Stack is used by the GC code and in some hot paths a lot of the Stack
31 // code gets inlined. This is generally good, but when too much code has
32 // been inlined, no further inlining is allowed by GCC. Therefore we need
33 // to prevent parts of the slow path in Stack to be inlined to allow other
34 // code to be.
35 #if defined(TARGET_COMPILER_gcc)
36 #define NOINLINE __attribute__((noinline))
37 #else
38 #define NOINLINE
39 #endif
40
41 template <MEMFLAGS F> StackBase<F>::StackBase(size_t segment_size, size_t max_cache_size,
42 size_t max_size):
43 _seg_size(segment_size),
44 _max_cache_size(max_cache_size),
45 _max_size(adjust_max_size(max_size, segment_size))
46 {
47 assert(_max_size % _seg_size == 0, "not a multiple");
48 }
49
50 template <MEMFLAGS F> size_t StackBase<F>::adjust_max_size(size_t max_size, size_t seg_size)
51 {
52 assert(seg_size > 0, "cannot be 0");
53 assert(max_size >= seg_size || max_size == 0, "max_size too small");
54 const size_t limit = max_uintx - (seg_size - 1);
55 if (max_size == 0 || max_size > limit) {
56 max_size = limit;
57 }
58 return (max_size + seg_size - 1) / seg_size * seg_size;
59 }
60
61 template <class E, MEMFLAGS F>
62 Stack<E, F>::Stack(size_t segment_size, size_t max_cache_size, size_t max_size):
63 StackBase<F>(adjust_segment_size(segment_size), max_cache_size, max_size)
64 {
65 reset(true);
66 }
67
68 template <class E, MEMFLAGS F>
69 void Stack<E, F>::push(E item)
70 {
71 assert(!is_full(), "pushing onto a full stack");
72 if (this->_cur_seg_size == this->_seg_size) {
73 push_segment();
74 }
75 this->_cur_seg[this->_cur_seg_size] = item;
76 ++this->_cur_seg_size;
77 }
78
79 template <class E, MEMFLAGS F>
80 E Stack<E, F>::pop()
81 {
82 assert(!is_empty(), "popping from an empty stack");
83 if (this->_cur_seg_size == 1) {
84 E tmp = _cur_seg[--this->_cur_seg_size];
85 pop_segment();
86 return tmp;
87 }
88 return this->_cur_seg[--this->_cur_seg_size];
89 }
90
91 template <class E, MEMFLAGS F>
92 void Stack<E, F>::clear(bool clear_cache)
93 {
94 free_segments(_cur_seg);
95 if (clear_cache) free_segments(_cache);
96 reset(clear_cache);
97 }
98
99 template <class E, MEMFLAGS F>
100 size_t Stack<E, F>::adjust_segment_size(size_t seg_size)
101 {
102 const size_t elem_sz = sizeof(E);
103 const size_t ptr_sz = sizeof(E*);
104 assert(elem_sz % ptr_sz == 0 || ptr_sz % elem_sz == 0, "bad element size");
105 if (elem_sz < ptr_sz) {
106 return align_size_up(seg_size * elem_sz, ptr_sz) / elem_sz;
107 }
108 return seg_size;
109 }
110
111 template <class E, MEMFLAGS F>
112 size_t Stack<E, F>::link_offset() const
113 {
114 return align_size_up(this->_seg_size * sizeof(E), sizeof(E*));
115 }
116
117 template <class E, MEMFLAGS F>
118 size_t Stack<E, F>::segment_bytes() const
119 {
120 return link_offset() + sizeof(E*);
121 }
122
123 template <class E, MEMFLAGS F>
124 E** Stack<E, F>::link_addr(E* seg) const
125 {
126 return (E**) ((char*)seg + link_offset());
127 }
128
129 template <class E, MEMFLAGS F>
130 E* Stack<E, F>::get_link(E* seg) const
131 {
132 return *link_addr(seg);
133 }
134
135 template <class E, MEMFLAGS F>
136 E* Stack<E, F>::set_link(E* new_seg, E* old_seg)
137 {
138 *link_addr(new_seg) = old_seg;
139 return new_seg;
140 }
141
142 template <class E, MEMFLAGS F>
143 E* Stack<E, F>::alloc(size_t bytes)
144 {
145 return (E*) NEW_C_HEAP_ARRAY(char, bytes, F);
146 }
147
148 template <class E, MEMFLAGS F>
149 void Stack<E, F>::free(E* addr, size_t bytes)
150 {
151 FREE_C_HEAP_ARRAY(char, (char*) addr);
152 }
153
154 template <class E, MEMFLAGS F>
155 NOINLINE void Stack<E, F>::push_segment()
156 {
157 assert(this->_cur_seg_size == this->_seg_size, "current segment is not full");
158 E* next;
159 if (this->_cache_size > 0) {
160 // Use a cached segment.
161 next = _cache;
162 _cache = get_link(_cache);
163 --this->_cache_size;
164 } else {
165 next = alloc(segment_bytes());
166 DEBUG_ONLY(zap_segment(next, true);)
167 }
168 const bool at_empty_transition = is_empty();
169 this->_cur_seg = set_link(next, _cur_seg);
170 this->_cur_seg_size = 0;
171 this->_full_seg_size += at_empty_transition ? 0 : this->_seg_size;
172 DEBUG_ONLY(verify(at_empty_transition);)
173 }
174
175 template <class E, MEMFLAGS F>
176 void Stack<E, F>::pop_segment()
177 {
178 assert(this->_cur_seg_size == 0, "current segment is not empty");
179 E* const prev = get_link(_cur_seg);
180 if (this->_cache_size < this->_max_cache_size) {
181 // Add the current segment to the cache.
182 DEBUG_ONLY(zap_segment(_cur_seg, false);)
183 _cache = set_link(_cur_seg, _cache);
184 ++this->_cache_size;
185 } else {
186 DEBUG_ONLY(zap_segment(_cur_seg, true);)
187 free(_cur_seg, segment_bytes());
188 }
189 const bool at_empty_transition = prev == NULL;
190 this->_cur_seg = prev;
191 this->_cur_seg_size = this->_seg_size;
192 this->_full_seg_size -= at_empty_transition ? 0 : this->_seg_size;
193 DEBUG_ONLY(verify(at_empty_transition);)
194 }
195
196 template <class E, MEMFLAGS F>
197 void Stack<E, F>::free_segments(E* seg)
198 {
199 const size_t bytes = segment_bytes();
200 while (seg != NULL) {
201 E* const prev = get_link(seg);
202 free(seg, bytes);
203 seg = prev;
204 }
205 }
206
207 template <class E, MEMFLAGS F>
208 void Stack<E, F>::reset(bool reset_cache)
209 {
210 this->_cur_seg_size = this->_seg_size; // So push() will alloc a new segment.
211 this->_full_seg_size = 0;
212 _cur_seg = NULL;
213 if (reset_cache) {
214 this->_cache_size = 0;
215 _cache = NULL;
216 }
217 }
218
219 #ifdef ASSERT
220 template <class E, MEMFLAGS F>
221 void Stack<E, F>::verify(bool at_empty_transition) const
222 {
223 assert(size() <= this->max_size(), "stack exceeded bounds");
224 assert(this->cache_size() <= this->max_cache_size(), "cache exceeded bounds");
225 assert(this->_cur_seg_size <= this->segment_size(), "segment index exceeded bounds");
226
227 assert(this->_full_seg_size % this->_seg_size == 0, "not a multiple");
228 assert(at_empty_transition || is_empty() == (size() == 0), "mismatch");
229 assert((_cache == NULL) == (this->cache_size() == 0), "mismatch");
230
231 if (is_empty()) {
232 assert(this->_cur_seg_size == this->segment_size(), "sanity");
233 }
234 }
235
236 template <class E, MEMFLAGS F>
237 void Stack<E, F>::zap_segment(E* seg, bool zap_link_field) const
238 {
239 if (!ZapStackSegments) return;
240 const size_t zap_bytes = segment_bytes() - (zap_link_field ? 0 : sizeof(E*));
241 uint32_t* cur = (uint32_t*)seg;
242 const uint32_t* end = cur + zap_bytes / sizeof(uint32_t);
243 while (cur < end) {
244 *cur++ = 0xfadfaded;
245 }
246 }
247 #endif
248
249 template <class E, MEMFLAGS F>
250 E* ResourceStack<E, F>::alloc(size_t bytes)
251 {
252 return (E*) resource_allocate_bytes(bytes);
253 }
254
255 template <class E, MEMFLAGS F>
256 void ResourceStack<E, F>::free(E* addr, size_t bytes)
257 {
258 resource_free_bytes((char*) addr, bytes);
259 }
260
261 template <class E, MEMFLAGS F>
262 void StackIterator<E, F>::sync()
263 {
264 _full_seg_size = _stack._full_seg_size;
265 _cur_seg_size = _stack._cur_seg_size;
266 _cur_seg = _stack._cur_seg;
267 }
268
269 template <class E, MEMFLAGS F>
270 E* StackIterator<E, F>::next_addr()
271 {
272 assert(!is_empty(), "no items left");
273 if (_cur_seg_size == 1) {
274 E* addr = _cur_seg;
275 _cur_seg = _stack.get_link(_cur_seg);
276 _cur_seg_size = _stack.segment_size();
277 _full_seg_size -= _stack.segment_size();
278 return addr;
279 }
280 return _cur_seg + --_cur_seg_size;
281 }
282
283 #undef NOINLINE
284
285 #endif // SHARE_VM_UTILITIES_STACK_INLINE_HPP