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/vtableStubs.hpp"
27 #include "compiler/compileBroker.hpp"
28 #include "compiler/disassembler.hpp"
29 #include "logging/log.hpp"
30 #include "memory/allocation.inline.hpp"
31 #include "memory/resourceArea.hpp"
32 #include "oops/instanceKlass.hpp"
33 #include "oops/klassVtable.hpp"
34 #include "oops/oop.inline.hpp"
35 #include "prims/forte.hpp"
36 #include "prims/jvmtiExport.hpp"
37 #include "runtime/handles.inline.hpp"
38 #include "runtime/mutexLocker.hpp"
39 #include "runtime/sharedRuntime.hpp"
40 #include "utilities/align.hpp"
41 #ifdef COMPILER2
42 #include "opto/matcher.hpp"
43 #endif
44
45 // -----------------------------------------------------------------------------------------
46 // Implementation of VtableStub
47
48 address VtableStub::_chunk = NULL;
49 address VtableStub::_chunk_end = NULL;
50 VMReg VtableStub::_receiver_location = VMRegImpl::Bad();
51
52
53 void* VtableStub::operator new(size_t size, int code_size) throw() {
54 assert_lock_strong(VtableStubs_lock);
55 assert(size == sizeof(VtableStub), "mismatched size");
56 // compute real VtableStub size (rounded to nearest word)
57 const int real_size = align_up(code_size + (int)sizeof(VtableStub), wordSize);
58 // malloc them in chunks to minimize header overhead
59 const int chunk_factor = 32;
60 if (_chunk == NULL || _chunk + real_size > _chunk_end) {
61 const int bytes = chunk_factor * real_size + pd_code_alignment();
62
63 // There is a dependency on the name of the blob in src/share/vm/prims/jvmtiCodeBlobEvents.cpp
64 // If changing the name, update the other file accordingly.
65 VtableBlob* blob = VtableBlob::create("vtable chunks", bytes);
66 if (blob == NULL) {
67 return NULL;
68 }
69 _chunk = blob->content_begin();
70 _chunk_end = _chunk + bytes;
71 Forte::register_stub("vtable stub", _chunk, _chunk_end);
72 align_chunk();
73 }
74 assert(_chunk + real_size <= _chunk_end, "bad allocation");
75 void* res = _chunk;
76 _chunk += real_size;
77 align_chunk();
78 return res;
79 }
80
81
82 void VtableStub::print_on(outputStream* st) const {
83 st->print("vtable stub (index = %d, receiver_location = " INTX_FORMAT ", code = [" INTPTR_FORMAT ", " INTPTR_FORMAT "[)",
84 index(), p2i(receiver_location()), p2i(code_begin()), p2i(code_end()));
85 }
86
87
88 // -----------------------------------------------------------------------------------------
89 // Implementation of VtableStubs
90 //
91 // For each hash value there's a linked list of vtable stubs (with that
92 // hash value). Each list is anchored in a little hash _table, indexed
93 // by that hash value.
94
95 VtableStub* VtableStubs::_table[VtableStubs::N];
96 int VtableStubs::_number_of_vtable_stubs = 0;
97 int VtableStubs::_vtab_stub_size = 0;
98 int VtableStubs::_itab_stub_size = 0;
99
100 #if defined(PRODUCT)
101 // These values are good for the PRODUCT case (no tracing).
102 static const int first_vtableStub_size = 64;
103 static const int first_itableStub_size = 256;
104 #else
105 // These values are good for the non-PRODUCT case (when tracing can be switched on).
106 // To find out, run test workload with
107 // -Xlog:vtablestubs=Trace -XX:+CountCompiledCalls -XX:+DebugVtables
108 // and use the reported "estimate" value.
109 // Here is a list of observed worst-case values:
110 // vtable itable
111 // aarch64: 460 324
112 // arm: ? ?
113 // ppc (linux, BE): 404 288
114 // ppc (linux, LE): 356 276
115 // ppc (AIX): 416 296
116 // s390x: 408 256
117 // Solaris-sparc: 792 348
118 // x86 (Linux): 670 309
119 // x86 (MacOS): 682 321
120 static const int first_vtableStub_size = 1024;
121 static const int first_itableStub_size = 512;
122 #endif
123
124
125 void VtableStubs::initialize() {
126 VtableStub::_receiver_location = SharedRuntime::name_for_receiver();
127 {
128 MutexLockerEx ml(VtableStubs_lock, Mutex::_no_safepoint_check_flag);
129 assert(_number_of_vtable_stubs == 0, "potential performance bug: VtableStubs initialized more than once");
130 assert(is_power_of_2(N), "N must be a power of 2");
131 for (int i = 0; i < N; i++) {
132 _table[i] = NULL;
133 }
134 }
135 }
136
137
138 int VtableStubs::code_size_limit(bool is_vtable_stub) {
139 if (is_vtable_stub) {
140 return _vtab_stub_size > 0 ? _vtab_stub_size : first_vtableStub_size;
141 } else { // itable stub
142 return _itab_stub_size > 0 ? _itab_stub_size : first_itableStub_size;
143 }
144 } // code_size_limit
145
146
147 void VtableStubs::check_and_set_size_limit(bool is_vtable_stub,
148 int code_size,
149 int padding) {
150 const char* name = is_vtable_stub ? "vtable" : "itable";
151
152 guarantee(code_size <= code_size_limit(is_vtable_stub),
153 "buffer overflow in %s stub, code_size is %d, limit is %d", name, code_size, code_size_limit(is_vtable_stub));
154
155 if (is_vtable_stub) {
156 if (log_is_enabled(Trace, vtablestubs)) {
157 if ( (_vtab_stub_size > 0) && ((code_size + padding) > _vtab_stub_size) ) {
158 log_trace(vtablestubs)("%s size estimate needed adjustment from %d to %d bytes",
159 name, _vtab_stub_size, code_size + padding);
160 }
161 }
162 if ( (code_size + padding) > _vtab_stub_size ) {
163 _vtab_stub_size = code_size + padding;
164 }
165 } else { // itable stub
166 if (log_is_enabled(Trace, vtablestubs)) {
167 if ( (_itab_stub_size > 0) && ((code_size + padding) > _itab_stub_size) ) {
168 log_trace(vtablestubs)("%s size estimate needed adjustment from %d to %d bytes",
169 name, _itab_stub_size, code_size + padding);
170 }
171 }
172 if ( (code_size + padding) > _itab_stub_size ) {
173 _itab_stub_size = code_size + padding;
174 }
175 }
176 return;
177 } // check_and_set_size_limit
178
179
180 void VtableStubs::bookkeeping(MacroAssembler* masm, outputStream* out, VtableStub* s,
181 address npe_addr, address ame_addr, bool is_vtable_stub,
182 int index, int slop_bytes, int index_dependent_slop) {
183 const char* name = is_vtable_stub ? "vtable" : "itable";
184 const int stub_length = code_size_limit(is_vtable_stub);
185
186 if (log_is_enabled(Trace, vtablestubs)) {
187 log_trace(vtablestubs)("%s #%d at " PTR_FORMAT ": size: %d, estimate: %d, slop area: %d",
188 name, index, p2i(s->code_begin()),
189 (int)(masm->pc() - s->code_begin()),
190 stub_length,
191 (int)(s->code_end() - masm->pc()));
192 }
193 guarantee(masm->pc() <= s->code_end(), "%s #%d: overflowed buffer, estimated len: %d, actual len: %d, overrun: %d",
194 name, index, stub_length,
195 (int)(masm->pc() - s->code_begin()),
196 (int)(masm->pc() - s->code_end()));
197 assert((masm->pc() + index_dependent_slop) <= s->code_end(), "%s #%d: spare space for 32-bit offset: required = %d, available = %d",
198 name, index, index_dependent_slop,
199 (int)(s->code_end() - masm->pc()));
200
201 // After the first vtable/itable stub is generated, we have a much
202 // better estimate for the stub size. Remember/update this
203 // estimate after some sanity checks.
204 check_and_set_size_limit(is_vtable_stub, masm->offset(), slop_bytes);
205 s->set_exception_points(npe_addr, ame_addr);
206 }
207
208
209 address VtableStubs::find_stub(bool is_vtable_stub, int vtable_index) {
210 assert(vtable_index >= 0, "must be positive");
211
212 VtableStub* s;
213 {
214 MutexLockerEx ml(VtableStubs_lock, Mutex::_no_safepoint_check_flag);
215 s = ShareVtableStubs ? lookup(is_vtable_stub, vtable_index) : NULL;
216 if (s == NULL) {
217 if (is_vtable_stub) {
218 s = create_vtable_stub(vtable_index);
219 } else {
220 s = create_itable_stub(vtable_index);
221 }
222
223 // Creation of vtable or itable can fail if there is not enough free space in the code cache.
224 if (s == NULL) {
225 return NULL;
226 }
227
228 enter(is_vtable_stub, vtable_index, s);
229 if (PrintAdapterHandlers) {
230 tty->print_cr("Decoding VtableStub %s[%d]@" INTX_FORMAT,
231 is_vtable_stub? "vtbl": "itbl", vtable_index, p2i(VtableStub::receiver_location()));
232 Disassembler::decode(s->code_begin(), s->code_end());
233 }
234 // Notify JVMTI about this stub. The event will be recorded by the enclosing
235 // JvmtiDynamicCodeEventCollector and posted when this thread has released
236 // all locks.
237 if (JvmtiExport::should_post_dynamic_code_generated()) {
238 JvmtiExport::post_dynamic_code_generated_while_holding_locks(is_vtable_stub? "vtable stub": "itable stub",
239 s->code_begin(), s->code_end());
240 }
241 }
242 }
243 return s->entry_point();
244 }
245
246
247 inline uint VtableStubs::hash(bool is_vtable_stub, int vtable_index){
248 // Assumption: receiver_location < 4 in most cases.
249 int hash = ((vtable_index << 2) ^ VtableStub::receiver_location()->value()) + vtable_index;
250 return (is_vtable_stub ? ~hash : hash) & mask;
251 }
252
253
254 VtableStub* VtableStubs::lookup(bool is_vtable_stub, int vtable_index) {
255 assert_lock_strong(VtableStubs_lock);
256 unsigned hash = VtableStubs::hash(is_vtable_stub, vtable_index);
257 VtableStub* s = _table[hash];
258 while( s && !s->matches(is_vtable_stub, vtable_index)) s = s->next();
259 return s;
260 }
261
262
263 void VtableStubs::enter(bool is_vtable_stub, int vtable_index, VtableStub* s) {
264 assert_lock_strong(VtableStubs_lock);
265 assert(s->matches(is_vtable_stub, vtable_index), "bad vtable stub");
266 unsigned int h = VtableStubs::hash(is_vtable_stub, vtable_index);
267 // enter s at the beginning of the corresponding list
268 s->set_next(_table[h]);
269 _table[h] = s;
270 _number_of_vtable_stubs++;
271 }
272
273 VtableStub* VtableStubs::entry_point(address pc) {
274 MutexLockerEx ml(VtableStubs_lock, Mutex::_no_safepoint_check_flag);
275 VtableStub* stub = (VtableStub*)(pc - VtableStub::entry_offset());
276 uint hash = VtableStubs::hash(stub->is_vtable_stub(), stub->index());
277 VtableStub* s;
278 for (s = _table[hash]; s != NULL && s != stub; s = s->next()) {}
279 return (s == stub) ? s : NULL;
280 }
281
282 bool VtableStubs::contains(address pc) {
283 // simple solution for now - we may want to use
284 // a faster way if this function is called often
285 return stub_containing(pc) != NULL;
286 }
287
288
289 VtableStub* VtableStubs::stub_containing(address pc) {
290 // Note: No locking needed since any change to the data structure
291 // happens with an atomic store into it (we don't care about
292 // consistency with the _number_of_vtable_stubs counter).
293 for (int i = 0; i < N; i++) {
294 for (VtableStub* s = _table[i]; s != NULL; s = s->next()) {
295 if (s->contains(pc)) return s;
296 }
297 }
298 return NULL;
299 }
300
301 void vtableStubs_init() {
302 VtableStubs::initialize();
303 }
304
305 void VtableStubs::vtable_stub_do(void f(VtableStub*)) {
306 for (int i = 0; i < N; i++) {
307 for (VtableStub* s = _table[i]; s != NULL; s = s->next()) {
308 f(s);
309 }
310 }
311 }
312
313
314 //-----------------------------------------------------------------------------------------------------
315 // Non-product code
316 #ifndef PRODUCT
317
318 extern "C" void bad_compiled_vtable_index(JavaThread* thread, oop receiver, int index) {
319 ResourceMark rm;
320 HandleMark hm;
321 Klass* klass = receiver->klass();
322 InstanceKlass* ik = InstanceKlass::cast(klass);
323 klassVtable vt = ik->vtable();
324 ik->print();
325 fatal("bad compiled vtable dispatch: receiver " INTPTR_FORMAT ", "
326 "index %d (vtable length %d)",
327 p2i(receiver), index, vt.length());
328 }
329
330 #endif // PRODUCT