1 /*
2 * Copyright (c) 1997, 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 #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 DEF_STUB_INTERFACE(ICStub);
42
43 StubQueue* InlineCacheBuffer::_buffer = NULL;
44 ICStub* InlineCacheBuffer::_next_stub = NULL;
45
46 CompiledICHolder* InlineCacheBuffer::_pending_released = NULL;
47 int InlineCacheBuffer::_pending_count = 0;
48
49 void ICStub::finalize() {
50 if (!is_empty()) {
51 ResourceMark rm;
52 CompiledIC *ic = CompiledIC_at(CodeCache::find_compiled(ic_site()), ic_site());
53 assert(CodeCache::find_compiled(ic->instruction_address()) != NULL, "inline cache in non-compiled?");
54
55 assert(this == ICStub_from_destination_address(ic->stub_address()), "wrong owner of ic buffer");
56 ic->set_ic_destination_and_value(destination(), cached_value());
57 }
58 }
59
60
61 address ICStub::destination() const {
62 return InlineCacheBuffer::ic_buffer_entry_point(code_begin());
63 }
64
65 void* ICStub::cached_value() const {
66 return InlineCacheBuffer::ic_buffer_cached_value(code_begin());
67 }
68
69
70 void ICStub::set_stub(CompiledIC *ic, void* cached_val, address dest_addr) {
71 // We cannot store a pointer to the 'ic' object, since it is resource allocated. Instead we
72 // store the location of the inline cache. Then we have enough information recreate the CompiledIC
73 // object when we need to remove the stub.
74 _ic_site = ic->instruction_address();
75
76 // Assemble new stub
77 InlineCacheBuffer::assemble_ic_buffer_code(code_begin(), cached_val, dest_addr);
78 assert(destination() == dest_addr, "can recover destination");
79 assert(cached_value() == cached_val, "can recover destination");
80 }
81
82
83 void ICStub::clear() {
84 if (CompiledIC::is_icholder_entry(destination())) {
85 InlineCacheBuffer::queue_for_release((CompiledICHolder*)cached_value());
86 }
87 _ic_site = NULL;
88 }
89
90
91 #ifndef PRODUCT
92 // anybody calling to this stub will trap
93
94 void ICStub::verify() {
95 }
96
97 void ICStub::print() {
98 tty->print_cr("ICStub: site: " INTPTR_FORMAT, p2i(_ic_site));
99 }
100 #endif
101
102 //-----------------------------------------------------------------------------------------------
103 // Implementation of InlineCacheBuffer
104
105 void InlineCacheBuffer::init_next_stub() {
106 ICStub* ic_stub = (ICStub*)buffer()->request_committed (ic_stub_code_size());
107 assert (ic_stub != NULL, "no room for a single stub");
108 set_next_stub(ic_stub);
109 }
110
111 void InlineCacheBuffer::initialize() {
112 if (_buffer != NULL) return; // already initialized
113 _buffer = new StubQueue(new ICStubInterface, 10*K, InlineCacheBuffer_lock, "InlineCacheBuffer");
114 assert (_buffer != NULL, "cannot allocate InlineCacheBuffer");
115 init_next_stub();
116 }
117
118
119 ICStub* InlineCacheBuffer::new_ic_stub() {
120 while (true) {
121 ICStub* ic_stub = (ICStub*)buffer()->request_committed(ic_stub_code_size());
122 if (ic_stub != NULL) {
123 return ic_stub;
124 }
125 // we ran out of inline cache buffer space; must enter safepoint.
126 // We do this by forcing a safepoint
127 EXCEPTION_MARK;
128
129 VM_ICBufferFull ibf;
130 VMThread::execute(&ibf);
131 // We could potential get an async. exception at this point.
132 // In that case we will rethrow it to ourselvs.
133 if (HAS_PENDING_EXCEPTION) {
134 oop exception = PENDING_EXCEPTION;
135 CLEAR_PENDING_EXCEPTION;
136 Thread::send_async_exception(JavaThread::current()->threadObj(), exception);
137 }
138 }
139 ShouldNotReachHere();
140 return NULL;
141 }
142
143
144 void InlineCacheBuffer::update_inline_caches() {
145 if (buffer()->number_of_stubs() > 1) {
146 if (TraceICBuffer) {
147 tty->print_cr("[updating inline caches with %d stubs]", buffer()->number_of_stubs());
148 }
149 buffer()->remove_all();
150 init_next_stub();
151 }
152 release_pending_icholders();
153 }
154
155
156 bool InlineCacheBuffer::contains(address instruction_address) {
157 return buffer()->contains(instruction_address);
158 }
159
160
161 bool InlineCacheBuffer::is_empty() {
162 return buffer()->number_of_stubs() == 1; // always has sentinel
163 }
164
165
166 void InlineCacheBuffer_init() {
167 InlineCacheBuffer::initialize();
168 }
169
170
171 void InlineCacheBuffer::create_transition_stub(CompiledIC *ic, void* cached_value, address entry) {
172 assert(!SafepointSynchronize::is_at_safepoint(), "should not be called during a safepoint");
173 assert (CompiledIC_lock->is_locked(), "");
174 if (TraceICBuffer) {
175 tty->print_cr(" create transition stub for " INTPTR_FORMAT " destination " INTPTR_FORMAT " cached value " INTPTR_FORMAT,
176 p2i(ic->instruction_address()), p2i(entry), p2i(cached_value));
177 }
178
179 // If an transition stub is already associate with the inline cache, then we remove the association.
180 if (ic->is_in_transition_state()) {
181 ICStub* old_stub = ICStub_from_destination_address(ic->stub_address());
182 old_stub->clear();
183 }
184
185 // allocate and initialize new "out-of-line" inline-cache
186 ICStub* ic_stub = get_next_stub();
187 ic_stub->set_stub(ic, cached_value, entry);
188
189 // Update inline cache in nmethod to point to new "out-of-line" allocated inline cache
190 ic->set_ic_destination(ic_stub);
191
192 set_next_stub(new_ic_stub()); // can cause safepoint synchronization
193 }
194
195
196 address InlineCacheBuffer::ic_destination_for(CompiledIC *ic) {
197 ICStub* stub = ICStub_from_destination_address(ic->stub_address());
198 return stub->destination();
199 }
200
201
202 void* InlineCacheBuffer::cached_value_for(CompiledIC *ic) {
203 ICStub* stub = ICStub_from_destination_address(ic->stub_address());
204 return stub->cached_value();
205 }
206
207
208 // Free CompiledICHolder*s that are no longer in use
209 void InlineCacheBuffer::release_pending_icholders() {
210 assert(SafepointSynchronize::is_at_safepoint(), "should only be called during a safepoint");
211 CompiledICHolder* holder = _pending_released;
212 _pending_released = NULL;
213 while (holder != NULL) {
214 CompiledICHolder* next = holder->next();
215 delete holder;
216 holder = next;
217 _pending_count--;
218 }
219 assert(_pending_count == 0, "wrong count");
220 }
221
222 // Enqueue this icholder for release during the next safepoint. It's
223 // not safe to free them until them since they might be visible to
224 // another thread.
225 void InlineCacheBuffer::queue_for_release(CompiledICHolder* icholder) {
226 MutexLockerEx mex(InlineCacheBuffer_lock);
227 icholder->set_next(_pending_released);
228 _pending_released = icholder;
229 _pending_count++;
230 if (TraceICBuffer) {
231 tty->print_cr("enqueueing icholder " INTPTR_FORMAT " to be freed", p2i(icholder));
232 }
233 }