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comparison src/share/vm/code/stubs.cpp @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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1 /*
2 * Copyright 1997-2005 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 #include "incls/_precompiled.incl"
26 #include "incls/_stubs.cpp.incl"
27
28
29 // Implementation of StubQueue
30 //
31 // Standard wrap-around queue implementation; the queue dimensions
32 // are specified by the _queue_begin & _queue_end indices. The queue
33 // can be in two states (transparent to the outside):
34 //
35 // a) contiguous state: all queue entries in one block (or empty)
36 //
37 // Queue: |...|XXXXXXX|...............|
38 // ^0 ^begin ^end ^size = limit
39 // |_______|
40 // one block
41 //
42 // b) non-contiguous state: queue entries in two blocks
43 //
44 // Queue: |XXX|.......|XXXXXXX|.......|
45 // ^0 ^end ^begin ^limit ^size
46 // |___| |_______|
47 // 1st block 2nd block
48 //
49 // In the non-contiguous state, the wrap-around point is
50 // indicated via the _buffer_limit index since the last
51 // queue entry may not fill up the queue completely in
52 // which case we need to know where the 2nd block's end
53 // is to do the proper wrap-around. When removing the
54 // last entry of the 2nd block, _buffer_limit is reset
55 // to _buffer_size.
56 //
57 // CAUTION: DO NOT MESS WITH THIS CODE IF YOU CANNOT PROVE
58 // ITS CORRECTNESS! THIS CODE IS MORE SUBTLE THAN IT LOOKS!
59
60
61 StubQueue::StubQueue(StubInterface* stub_interface, int buffer_size,
62 Mutex* lock, const char* name) : _mutex(lock) {
63 intptr_t size = round_to(buffer_size, 2*BytesPerWord);
64 BufferBlob* blob = BufferBlob::create(name, size);
65 if( blob == NULL ) vm_exit_out_of_memory1(size, "CodeCache: no room for %s", name);
66 _stub_interface = stub_interface;
67 _buffer_size = blob->instructions_size();
68 _buffer_limit = blob->instructions_size();
69 _stub_buffer = blob->instructions_begin();
70 _queue_begin = 0;
71 _queue_end = 0;
72 _number_of_stubs = 0;
73 register_queue(this);
74 }
75
76
77 StubQueue::~StubQueue() {
78 // Note: Currently StubQueues are never destroyed so nothing needs to be done here.
79 // If we want to implement the destructor, we need to release the BufferBlob
80 // allocated in the constructor (i.e., we need to keep it around or look it
81 // up via CodeCache::find_blob(...).
82 Unimplemented();
83 }
84
85
86 Stub* StubQueue::stub_containing(address pc) const {
87 if (contains(pc)) {
88 for (Stub* s = first(); s != NULL; s = next(s)) {
89 if (stub_contains(s, pc)) return s;
90 }
91 }
92 return NULL;
93 }
94
95
96 Stub* StubQueue::request_committed(int code_size) {
97 Stub* s = request(code_size);
98 if (s != NULL) commit(code_size);
99 return s;
100 }
101
102
103 Stub* StubQueue::request(int requested_code_size) {
104 assert(requested_code_size > 0, "requested_code_size must be > 0");
105 if (_mutex != NULL) _mutex->lock();
106 Stub* s = current_stub();
107 int requested_size = round_to(stub_code_size_to_size(requested_code_size), CodeEntryAlignment);
108 if (requested_size <= available_space()) {
109 if (is_contiguous()) {
110 // Queue: |...|XXXXXXX|.............|
111 // ^0 ^begin ^end ^size = limit
112 assert(_buffer_limit == _buffer_size, "buffer must be fully usable");
113 if (_queue_end + requested_size <= _buffer_size) {
114 // code fits in at the end => nothing to do
115 stub_initialize(s, requested_size);
116 return s;
117 } else {
118 // stub doesn't fit in at the queue end
119 // => reduce buffer limit & wrap around
120 assert(!is_empty(), "just checkin'");
121 _buffer_limit = _queue_end;
122 _queue_end = 0;
123 }
124 }
125 }
126 if (requested_size <= available_space()) {
127 assert(!is_contiguous(), "just checkin'");
128 assert(_buffer_limit <= _buffer_size, "queue invariant broken");
129 // Queue: |XXX|.......|XXXXXXX|.......|
130 // ^0 ^end ^begin ^limit ^size
131 s = current_stub();
132 stub_initialize(s, requested_size);
133 return s;
134 }
135 // Not enough space left
136 if (_mutex != NULL) _mutex->unlock();
137 return NULL;
138 }
139
140
141 void StubQueue::commit(int committed_code_size) {
142 assert(committed_code_size > 0, "committed_code_size must be > 0");
143 int committed_size = round_to(stub_code_size_to_size(committed_code_size), CodeEntryAlignment);
144 Stub* s = current_stub();
145 assert(committed_size <= stub_size(s), "committed size must not exceed requested size");
146 stub_initialize(s, committed_size);
147 _queue_end += committed_size;
148 _number_of_stubs++;
149 if (_mutex != NULL) _mutex->unlock();
150 debug_only(stub_verify(s);)
151 }
152
153
154 void StubQueue::remove_first() {
155 if (number_of_stubs() == 0) return;
156 Stub* s = first();
157 debug_only(stub_verify(s);)
158 stub_finalize(s);
159 _queue_begin += stub_size(s);
160 assert(_queue_begin <= _buffer_limit, "sanity check");
161 if (_queue_begin == _queue_end) {
162 // buffer empty
163 // => reset queue indices
164 _queue_begin = 0;
165 _queue_end = 0;
166 _buffer_limit = _buffer_size;
167 } else if (_queue_begin == _buffer_limit) {
168 // buffer limit reached
169 // => reset buffer limit & wrap around
170 _buffer_limit = _buffer_size;
171 _queue_begin = 0;
172 }
173 _number_of_stubs--;
174 }
175
176
177 void StubQueue::remove_first(int n) {
178 int i = MIN2(n, number_of_stubs());
179 while (i-- > 0) remove_first();
180 }
181
182
183 void StubQueue::remove_all(){
184 debug_only(verify();)
185 remove_first(number_of_stubs());
186 assert(number_of_stubs() == 0, "sanity check");
187 }
188
189
190 enum { StubQueueLimit = 10 }; // there are only a few in the world
191 static StubQueue* registered_stub_queues[StubQueueLimit];
192
193 void StubQueue::register_queue(StubQueue* sq) {
194 for (int i = 0; i < StubQueueLimit; i++) {
195 if (registered_stub_queues[i] == NULL) {
196 registered_stub_queues[i] = sq;
197 return;
198 }
199 }
200 ShouldNotReachHere();
201 }
202
203
204 void StubQueue::queues_do(void f(StubQueue* sq)) {
205 for (int i = 0; i < StubQueueLimit; i++) {
206 if (registered_stub_queues[i] != NULL) {
207 f(registered_stub_queues[i]);
208 }
209 }
210 }
211
212
213 void StubQueue::stubs_do(void f(Stub* s)) {
214 debug_only(verify();)
215 MutexLockerEx lock(_mutex);
216 for (Stub* s = first(); s != NULL; s = next(s)) f(s);
217 }
218
219
220 void StubQueue::verify() {
221 // verify only if initialized
222 if (_stub_buffer == NULL) return;
223 MutexLockerEx lock(_mutex);
224 // verify index boundaries
225 guarantee(0 <= _buffer_size, "buffer size must be positive");
226 guarantee(0 <= _buffer_limit && _buffer_limit <= _buffer_size , "_buffer_limit out of bounds");
227 guarantee(0 <= _queue_begin && _queue_begin < _buffer_limit, "_queue_begin out of bounds");
228 guarantee(0 <= _queue_end && _queue_end <= _buffer_limit, "_queue_end out of bounds");
229 // verify alignment
230 guarantee(_buffer_size % CodeEntryAlignment == 0, "_buffer_size not aligned");
231 guarantee(_buffer_limit % CodeEntryAlignment == 0, "_buffer_limit not aligned");
232 guarantee(_queue_begin % CodeEntryAlignment == 0, "_queue_begin not aligned");
233 guarantee(_queue_end % CodeEntryAlignment == 0, "_queue_end not aligned");
234 // verify buffer limit/size relationship
235 if (is_contiguous()) {
236 guarantee(_buffer_limit == _buffer_size, "_buffer_limit must equal _buffer_size");
237 }
238 // verify contents
239 int n = 0;
240 for (Stub* s = first(); s != NULL; s = next(s)) {
241 stub_verify(s);
242 n++;
243 }
244 guarantee(n == number_of_stubs(), "number of stubs inconsistent");
245 guarantee(_queue_begin != _queue_end || n == 0, "buffer indices must be the same");
246 }
247
248
249 void StubQueue::print() {
250 MutexLockerEx lock(_mutex);
251 for (Stub* s = first(); s != NULL; s = next(s)) {
252 stub_print(s);
253 }
254 }