1 /*
2 * Copyright (c) 1997, 2018, 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.hpp"
36 #include "oops/method.hpp"
37 #include "oops/oop.inline.hpp"
38 #include "runtime/handles.inline.hpp"
39 #include "runtime/mutexLocker.hpp"
40 #include "runtime/stubRoutines.hpp"
41
42 DEF_STUB_INTERFACE(ICStub);
43
44 StubQueue* InlineCacheBuffer::_buffer = NULL;
45
46 CompiledICHolder* InlineCacheBuffer::_pending_released = NULL;
47 int InlineCacheBuffer::_pending_count = 0;
48 DEBUG_ONLY(volatile int InlineCacheBuffer::_needs_refill = 0;)
49
50 void ICStub::finalize() {
51 if (!is_empty()) {
52 ResourceMark rm;
53 CompiledIC *ic = CompiledIC_at(CodeCache::find_compiled(ic_site()), ic_site());
54 assert(CodeCache::find_compiled(ic->instruction_address()) != NULL, "inline cache in non-compiled?");
55
56 assert(this == ICStub_from_destination_address(ic->stub_address()), "wrong owner of ic buffer");
57 ic->set_ic_destination_and_value(destination(), cached_value());
58 }
59 }
60
61
62 address ICStub::destination() const {
63 return InlineCacheBuffer::ic_buffer_entry_point(code_begin());
64 }
65
66 void* ICStub::cached_value() const {
67 return InlineCacheBuffer::ic_buffer_cached_value(code_begin());
68 }
69
70
71 void ICStub::set_stub(CompiledIC *ic, void* cached_val, address dest_addr) {
72 // We cannot store a pointer to the 'ic' object, since it is resource allocated. Instead we
73 // store the location of the inline cache. Then we have enough information recreate the CompiledIC
74 // object when we need to remove the stub.
75 _ic_site = ic->instruction_address();
76
77 // Assemble new stub
78 InlineCacheBuffer::assemble_ic_buffer_code(code_begin(), cached_val, dest_addr);
79 assert(destination() == dest_addr, "can recover destination");
80 assert(cached_value() == cached_val, "can recover destination");
81 }
82
83
84 void ICStub::clear() {
85 if (CompiledIC::is_icholder_entry(destination())) {
86 InlineCacheBuffer::queue_for_release((CompiledICHolder*)cached_value());
87 }
88 _ic_site = NULL;
89 }
90
91
92 #ifndef PRODUCT
93 // anybody calling to this stub will trap
94
95 void ICStub::verify() {
96 }
97
98 void ICStub::print() {
99 tty->print_cr("ICStub: site: " INTPTR_FORMAT, p2i(_ic_site));
100 }
101 #endif
102
103 //-----------------------------------------------------------------------------------------------
104 // Implementation of InlineCacheBuffer
105
106
107 void InlineCacheBuffer::initialize() {
108 if (_buffer != NULL) return; // already initialized
109 _buffer = new StubQueue(new ICStubInterface, 10*K, InlineCacheBuffer_lock, "InlineCacheBuffer");
110 assert (_buffer != NULL, "cannot allocate InlineCacheBuffer");
111 }
112
113
114 ICStub* InlineCacheBuffer::new_ic_stub() {
115 return (ICStub*)buffer()->request_committed(ic_stub_code_size());
116 }
117
118
119 void InlineCacheBuffer::refill_ic_stubs() {
120 DEBUG_ONLY(Atomic::store(0, &_needs_refill));
121 // we ran out of inline cache buffer space; must enter safepoint.
122 // We do this by forcing a safepoint
123 EXCEPTION_MARK;
124
125 VM_ICBufferFull ibf;
126 VMThread::execute(&ibf);
127 // We could potential get an async. exception at this point.
128 // In that case we will rethrow it to ourselvs.
129 if (HAS_PENDING_EXCEPTION) {
130 oop exception = PENDING_EXCEPTION;
131 CLEAR_PENDING_EXCEPTION;
132 Thread::send_async_exception(JavaThread::current()->threadObj(), exception);
133 }
134 }
135
136
137 void InlineCacheBuffer::update_inline_caches() {
138 assert(_needs_refill == 0,
139 "Forgot to handle a failed IC transition requiring IC stubs");
140 if (buffer()->number_of_stubs() > 0) {
141 if (TraceICBuffer) {
142 tty->print_cr("[updating inline caches with %d stubs]", buffer()->number_of_stubs());
143 }
144 buffer()->remove_all();
145 }
146 release_pending_icholders();
147 }
148
149
150 bool InlineCacheBuffer::contains(address instruction_address) {
151 return buffer()->contains(instruction_address);
152 }
153
154
155 bool InlineCacheBuffer::is_empty() {
156 return buffer()->number_of_stubs() == 0;
157 }
158
159
160 void InlineCacheBuffer_init() {
161 InlineCacheBuffer::initialize();
162 }
163
164
165 bool InlineCacheBuffer::create_transition_stub(CompiledIC *ic, void* cached_value, address entry) {
166 assert(!SafepointSynchronize::is_at_safepoint(), "should not be called during a safepoint");
167 assert(CompiledICLocker::is_safe(ic->instruction_address()), "mt unsafe call");
168 if (TraceICBuffer) {
169 tty->print_cr(" create transition stub for " INTPTR_FORMAT " destination " INTPTR_FORMAT " cached value " INTPTR_FORMAT,
170 p2i(ic->instruction_address()), p2i(entry), p2i(cached_value));
171 }
172
173 // allocate and initialize new "out-of-line" inline-cache
174 ICStub* ic_stub = new_ic_stub();
175 if (ic_stub == NULL) {
176 DEBUG_ONLY(Atomic::inc(&_needs_refill));
177 return false;
178 }
179
180 // If an transition stub is already associate with the inline cache, then we remove the association.
181 if (ic->is_in_transition_state()) {
182 ICStub* old_stub = ICStub_from_destination_address(ic->stub_address());
183 old_stub->clear();
184 }
185
186 ic_stub->set_stub(ic, cached_value, entry);
187
188 // Update inline cache in nmethod to point to new "out-of-line" allocated inline cache
189 ic->set_ic_destination(ic_stub);
190 return true;
191 }
192
193
194 address InlineCacheBuffer::ic_destination_for(CompiledIC *ic) {
195 ICStub* stub = ICStub_from_destination_address(ic->stub_address());
196 return stub->destination();
197 }
198
199
200 void* InlineCacheBuffer::cached_value_for(CompiledIC *ic) {
201 ICStub* stub = ICStub_from_destination_address(ic->stub_address());
202 return stub->cached_value();
203 }
204
205
206 // Free CompiledICHolder*s that are no longer in use
207 void InlineCacheBuffer::release_pending_icholders() {
208 assert(SafepointSynchronize::is_at_safepoint(), "should only be called during a safepoint");
209 CompiledICHolder* holder = _pending_released;
210 _pending_released = NULL;
211 while (holder != NULL) {
212 CompiledICHolder* next = holder->next();
213 delete holder;
214 holder = next;
215 _pending_count--;
216 }
217 assert(_pending_count == 0, "wrong count");
218 }
219
220 // Enqueue this icholder for release during the next safepoint. It's
221 // not safe to free them until them since they might be visible to
222 // another thread.
223 void InlineCacheBuffer::queue_for_release(CompiledICHolder* icholder) {
224 MutexLockerEx mex(InlineCacheBuffer_lock, Mutex::_no_safepoint_check_flag);
225 icholder->set_next(_pending_released);
226 _pending_released = icholder;
227 _pending_count++;
228 if (TraceICBuffer) {
229 tty->print_cr("enqueueing icholder " INTPTR_FORMAT " to be freed", p2i(icholder));
230 }
231 }