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