1 /*
2 * Copyright (c) 1997, 2015, 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 #include "precompiled.hpp"
26 #include "code/codeCache.hpp"
27 #include "code/compiledIC.hpp"
28 #include "code/icBuffer.hpp"
29 #include "code/nmethod.hpp"
30 #include "code/scopeDesc.hpp"
31 #include "gc/shared/collectedHeap.inline.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "interpreter/linkResolver.hpp"
34 #include "memory/resourceArea.hpp"
35 #include "memory/universe.inline.hpp"
36 #include "oops/method.hpp"
37 #include "oops/oop.inline.hpp"
38 #include "runtime/mutexLocker.hpp"
39 #include "runtime/stubRoutines.hpp"
40
41 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
42
43 DEF_STUB_INTERFACE(ICStub);
44
45 StubQueue* InlineCacheBuffer::_buffer = NULL;
46 ICStub* InlineCacheBuffer::_next_stub = NULL;
47
48 CompiledICHolder* InlineCacheBuffer::_pending_released = NULL;
49 int InlineCacheBuffer::_pending_count = 0;
50
51 void ICStub::finalize() {
52 if (!is_empty()) {
53 ResourceMark rm;
54 CompiledIC *ic = CompiledIC_at(CodeCache::find_nmethod(ic_site()), ic_site());
55 assert(CodeCache::find_nmethod(ic->instruction_address()) != NULL, "inline cache in non-nmethod?");
56
57 assert(this == ICStub_from_destination_address(ic->stub_address()), "wrong owner of ic buffer");
58 ic->set_ic_destination_and_value(destination(), cached_value());
59 }
60 }
61
62
63 address ICStub::destination() const {
64 return InlineCacheBuffer::ic_buffer_entry_point(code_begin());
65 }
66
67 void* ICStub::cached_value() const {
68 return InlineCacheBuffer::ic_buffer_cached_value(code_begin());
69 }
70
71
72 void ICStub::set_stub(CompiledIC *ic, void* cached_val, address dest_addr) {
73 // We cannot store a pointer to the 'ic' object, since it is resource allocated. Instead we
74 // store the location of the inline cache. Then we have enough information recreate the CompiledIC
75 // object when we need to remove the stub.
76 _ic_site = ic->instruction_address();
77
78 // Assemble new stub
79 InlineCacheBuffer::assemble_ic_buffer_code(code_begin(), cached_val, dest_addr);
80 assert(destination() == dest_addr, "can recover destination");
81 assert(cached_value() == cached_val, "can recover destination");
82 }
83
84
85 void ICStub::clear() {
86 if (CompiledIC::is_icholder_entry(destination())) {
87 InlineCacheBuffer::queue_for_release((CompiledICHolder*)cached_value());
88 }
89 _ic_site = NULL;
90 }
91
92
93 #ifndef PRODUCT
94 // anybody calling to this stub will trap
95
96 void ICStub::verify() {
97 }
98
99 void ICStub::print() {
100 tty->print_cr("ICStub: site: " INTPTR_FORMAT, _ic_site);
101 }
102 #endif
103
104 //-----------------------------------------------------------------------------------------------
105 // Implementation of InlineCacheBuffer
106
107 void InlineCacheBuffer::init_next_stub() {
108 ICStub* ic_stub = (ICStub*)buffer()->request_committed (ic_stub_code_size());
109 assert (ic_stub != NULL, "no room for a single stub");
110 set_next_stub(ic_stub);
111 }
112
113 void InlineCacheBuffer::initialize() {
114 if (_buffer != NULL) return; // already initialized
115 _buffer = new StubQueue(new ICStubInterface, 10*K, InlineCacheBuffer_lock, "InlineCacheBuffer");
116 assert (_buffer != NULL, "cannot allocate InlineCacheBuffer");
117 init_next_stub();
118 }
119
120
121 ICStub* InlineCacheBuffer::new_ic_stub() {
122 while (true) {
123 ICStub* ic_stub = (ICStub*)buffer()->request_committed(ic_stub_code_size());
124 if (ic_stub != NULL) {
125 return ic_stub;
126 }
127 // we ran out of inline cache buffer space; must enter safepoint.
128 // We do this by forcing a safepoint
129 EXCEPTION_MARK;
130
131 VM_ForceSafepoint vfs;
132 VMThread::execute(&vfs);
133 // We could potential get an async. exception at this point.
134 // In that case we will rethrow it to ourselvs.
135 if (HAS_PENDING_EXCEPTION) {
136 oop exception = PENDING_EXCEPTION;
137 CLEAR_PENDING_EXCEPTION;
138 Thread::send_async_exception(JavaThread::current()->threadObj(), exception);
139 }
140 }
141 ShouldNotReachHere();
142 return NULL;
143 }
144
145
146 void InlineCacheBuffer::update_inline_caches() {
147 if (buffer()->number_of_stubs() > 1) {
148 if (TraceICBuffer) {
149 tty->print_cr("[updating inline caches with %d stubs]", buffer()->number_of_stubs());
150 }
151 buffer()->remove_all();
152 init_next_stub();
153 }
154 release_pending_icholders();
155 }
156
157
158 bool InlineCacheBuffer::contains(address instruction_address) {
159 return buffer()->contains(instruction_address);
160 }
161
162
163 bool InlineCacheBuffer::is_empty() {
164 return buffer()->number_of_stubs() == 1; // always has sentinel
165 }
166
167
168 void InlineCacheBuffer_init() {
169 InlineCacheBuffer::initialize();
170 }
171
172
173 void InlineCacheBuffer::create_transition_stub(CompiledIC *ic, void* cached_value, address entry) {
174 assert(!SafepointSynchronize::is_at_safepoint(), "should not be called during a safepoint");
175 assert (CompiledIC_lock->is_locked(), "");
176 if (TraceICBuffer) {
177 tty->print_cr(" create transition stub for " INTPTR_FORMAT " destination " INTPTR_FORMAT " cached value " INTPTR_FORMAT,
178 ic->instruction_address(), entry, cached_value);
179 }
180
181 // If an transition stub is already associate with the inline cache, then we remove the association.
182 if (ic->is_in_transition_state()) {
183 ICStub* old_stub = ICStub_from_destination_address(ic->stub_address());
184 old_stub->clear();
185 }
186
187 // allocate and initialize new "out-of-line" inline-cache
188 ICStub* ic_stub = get_next_stub();
189 ic_stub->set_stub(ic, cached_value, entry);
190
191 // Update inline cache in nmethod to point to new "out-of-line" allocated inline cache
192 ic->set_ic_destination(ic_stub);
193
194 set_next_stub(new_ic_stub()); // can cause safepoint synchronization
195 }
196
197
198 address InlineCacheBuffer::ic_destination_for(CompiledIC *ic) {
199 ICStub* stub = ICStub_from_destination_address(ic->stub_address());
200 return stub->destination();
201 }
202
203
204 void* InlineCacheBuffer::cached_value_for(CompiledIC *ic) {
205 ICStub* stub = ICStub_from_destination_address(ic->stub_address());
206 return stub->cached_value();
207 }
208
209
210 // Free CompiledICHolder*s that are no longer in use
211 void InlineCacheBuffer::release_pending_icholders() {
212 assert(SafepointSynchronize::is_at_safepoint(), "should only be called during a safepoint");
213 CompiledICHolder* holder = _pending_released;
214 _pending_released = NULL;
215 while (holder != NULL) {
216 CompiledICHolder* next = holder->next();
217 delete holder;
218 holder = next;
219 _pending_count--;
220 }
221 assert(_pending_count == 0, "wrong count");
222 }
223
224 // Enqueue this icholder for release during the next safepoint. It's
225 // not safe to free them until them since they might be visible to
226 // another thread.
227 void InlineCacheBuffer::queue_for_release(CompiledICHolder* icholder) {
228 MutexLockerEx mex(InlineCacheBuffer_lock);
229 icholder->set_next(_pending_released);
230 _pending_released = icholder;
231 _pending_count++;
232 if (TraceICBuffer) {
233 tty->print_cr("enqueueing icholder " INTPTR_FORMAT " to be freed", icholder);
234 }
235 }