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 "memory/allocation.inline.hpp"
30 #include "memory/resourceArea.hpp"
31 #include "oops/instanceKlass.hpp"
32 #include "oops/klassVtable.hpp"
33 #include "oops/oop.inline.hpp"
34 #include "prims/forte.hpp"
35 #include "prims/jvmtiExport.hpp"
36 #include "runtime/handles.inline.hpp"
37 #include "runtime/mutexLocker.hpp"
38 #include "runtime/sharedRuntime.hpp"
39 #include "utilities/align.hpp"
40 #ifdef COMPILER2
41 #include "opto/matcher.hpp"
42 #endif
43
44 // -----------------------------------------------------------------------------------------
45 // Implementation of VtableStub
46
47 address VtableStub::_chunk = NULL;
48 address VtableStub::_chunk_end = NULL;
49 VMReg VtableStub::_receiver_location = VMRegImpl::Bad();
50
51
52 void* VtableStub::operator new(size_t size, int code_size) throw() {
53 assert(size == sizeof(VtableStub), "mismatched size");
54 // compute real VtableStub size (rounded to nearest word)
55 const int real_size = align_up(code_size + (int)sizeof(VtableStub), wordSize);
56 // malloc them in chunks to minimize header overhead
57 const int chunk_factor = 32;
58 if (_chunk == NULL || _chunk + real_size > _chunk_end) {
59 const int bytes = chunk_factor * real_size + pd_code_alignment();
60
61 // There is a dependency on the name of the blob in src/share/vm/prims/jvmtiCodeBlobEvents.cpp
62 // If changing the name, update the other file accordingly.
63 VtableBlob* blob = VtableBlob::create("vtable chunks", bytes);
64 if (blob == NULL) {
65 return NULL;
66 }
67 _chunk = blob->content_begin();
68 _chunk_end = _chunk + bytes;
69 Forte::register_stub("vtable stub", _chunk, _chunk_end);
70 align_chunk();
71 }
72 assert(_chunk + real_size <= _chunk_end, "bad allocation");
73 void* res = _chunk;
74 _chunk += real_size;
75 align_chunk();
76 return res;
77 }
78
79
80 void VtableStub::print_on(outputStream* st) const {
81 st->print("vtable stub (index = %d, receiver_location = " INTX_FORMAT ", code = [" INTPTR_FORMAT ", " INTPTR_FORMAT "[)",
82 index(), p2i(receiver_location()), p2i(code_begin()), p2i(code_end()));
83 }
84
85
86 // -----------------------------------------------------------------------------------------
87 // Implementation of VtableStubs
88 //
89 // For each hash value there's a linked list of vtable stubs (with that
90 // hash value). Each list is anchored in a little hash _table, indexed
91 // by that hash value.
92
93 VtableStub* VtableStubs::_table[VtableStubs::N];
94 int VtableStubs::_number_of_vtable_stubs = 0;
95 int VtableStubs::_vtab_stub_size = 0;
96 int VtableStubs::_itab_stub_size = 0;
97
98 #if defined(PRODUCT)
99 // These values are good for the PRODUCT case (no tracing).
100 static const int first_vtableStub_size = 64;
101 static const int first_itableStub_size = 256;
102 #else
103 // These values are good for the non-PRODUCT case (when tracing can be switched on).
104 // Here is a list of observed worst-case values:
105 // vtable itable
106 // aarch64:
107 // arm:
108 // ppc (linux, BE): 404 288
109 // ppc (linux, LE): 356 276
110 // ppc (AIX): 416 296
111 // s390x: 408 256
112 // Solaris-sparc: 748 348
113 // x86 (Linux): 670 309
114 // x86 (MacOS): 682 321
115 static const int first_vtableStub_size = 1024;
116 static const int first_itableStub_size = 512;
117 #endif
118
119
120 void VtableStubs::initialize() {
121 VtableStub::_receiver_location = SharedRuntime::name_for_receiver();
122 {
123 MutexLocker ml(VtableStubs_lock);
124 assert(_number_of_vtable_stubs == 0, "potential performance bug: VtableStubs initialized more than once");
125 assert(is_power_of_2(N), "N must be a power of 2");
126 for (int i = 0; i < N; i++) {
127 _table[i] = NULL;
128 }
129 }
130 }
131
132
133 int VtableStubs::code_size_limit(bool is_vtable_stub) {
134 if (is_vtable_stub) {
135 return _vtab_stub_size > 0 ? _vtab_stub_size : first_vtableStub_size;
136 } else { // itable stub
137 return _itab_stub_size > 0 ? _itab_stub_size : first_itableStub_size;
138 }
139 } // code_size_limit
140
141
142 void VtableStubs::check_and_set_size_limit(bool is_vtable_stub,
143 int code_size,
144 int padding) {
145 const char* name = is_vtable_stub ? "vtable" : "itable";
146
147 guarantee(code_size <= code_size_limit(is_vtable_stub),
148 "buffer overflow in %s stub, code_size is %d, limit is %d", name, code_size, code_size_limit(is_vtable_stub));
149
150 if (is_vtable_stub) {
151 if (log_is_enabled(Trace, vtablestubs)) {
152 if ( (_vtab_stub_size > 0) && ((code_size + padding) > _vtab_stub_size) ) {
153 log_trace(vtablestubs)("%s size estimate needed adjustment from %d to %d bytes",
154 name, _vtab_stub_size, code_size + padding);
155 }
156 }
157 if ( (code_size + padding) > _vtab_stub_size ) {
158 _vtab_stub_size = code_size + padding;
159 }
160 } else { // itable stub
161 if (log_is_enabled(Trace, vtablestubs)) {
162 if ( (_itab_stub_size > 0) && ((code_size + padding) > _itab_stub_size) ) {
163 log_trace(vtablestubs)("%s size estimate needed adjustment from %d to %d bytes",
164 name, _itab_stub_size, code_size + padding);
165 }
166 }
167 if ( (code_size + padding) > _itab_stub_size ) {
168 _itab_stub_size = code_size + padding;
169 }
170 }
171 return;
172 } // check_and_set_size_limit
173
174
175 void VtableStubs::bookkeeping(MacroAssembler* masm, outputStream* out, VtableStub* s,
176 address npe_addr, address ame_addr, bool is_vtable_stub,
177 int index, int slop_bytes, int slop32) {
178 const char* name = is_vtable_stub ? "vtable" : "itable";
179 const int stub_length = code_size_limit(is_vtable_stub);
180
181 if (log_is_enabled(Trace, vtablestubs)) {
182 log_trace(vtablestubs)("%s #%d at " PTR_FORMAT ": size: %d, estimate: %d, slop area: %d",
183 name, index, p2i(s->code_begin()),
184 (int)(masm->pc() - s->code_begin()),
185 stub_length,
186 (int)(s->code_end() - masm->pc()));
187 }
188 guarantee(masm->pc() <= s->code_end(), "%s #%d: overflowed buffer, estimated len: %d, actual len: %d, overrun: %d",
189 name, index, stub_length,
190 (int)(masm->pc() - s->code_begin()),
191 (int)(masm->pc() - s->code_end()));
192 assert((masm->pc() + slop32) <= s->code_end(), "%s #%d: spare space for 32-bit offset: required = %d, available = %d",
193 name, index, slop32,
194 (int)(s->code_end() - masm->pc()));
195
196 // After the first vtable/itable stub is generated, we have a much
197 // better estimate for the stub size. Remember/update this
198 // estimate after some sanity checks.
199 check_and_set_size_limit(is_vtable_stub, masm->offset(), slop_bytes);
200 s->set_exception_points(npe_addr, ame_addr);
201 }
202
203
204 address VtableStubs::find_stub(bool is_vtable_stub, int vtable_index) {
205 assert(vtable_index >= 0, "must be positive");
206
207 VtableStub* s = ShareVtableStubs ? lookup(is_vtable_stub, vtable_index) : NULL;
208 if (s == NULL) {
209 if (is_vtable_stub) {
210 s = create_vtable_stub(vtable_index);
211 } else {
212 s = create_itable_stub(vtable_index);
213 }
214
215 // Creation of vtable or itable can fail if there is not enough free space in the code cache.
216 if (s == NULL) {
217 return NULL;
218 }
219
220 enter(is_vtable_stub, vtable_index, s);
221 if (PrintAdapterHandlers) {
222 tty->print_cr("Decoding VtableStub %s[%d]@" INTX_FORMAT,
223 is_vtable_stub? "vtbl": "itbl", vtable_index, p2i(VtableStub::receiver_location()));
224 Disassembler::decode(s->code_begin(), s->code_end());
225 }
226 // Notify JVMTI about this stub. The event will be recorded by the enclosing
227 // JvmtiDynamicCodeEventCollector and posted when this thread has released
228 // all locks.
229 if (JvmtiExport::should_post_dynamic_code_generated()) {
230 JvmtiExport::post_dynamic_code_generated_while_holding_locks(is_vtable_stub? "vtable stub": "itable stub",
231 s->code_begin(), s->code_end());
232 }
233 }
234 return s->entry_point();
235 }
236
237
238 inline uint VtableStubs::hash(bool is_vtable_stub, int vtable_index){
239 // Assumption: receiver_location < 4 in most cases.
240 int hash = ((vtable_index << 2) ^ VtableStub::receiver_location()->value()) + vtable_index;
241 return (is_vtable_stub ? ~hash : hash) & mask;
242 }
243
244
245 VtableStub* VtableStubs::lookup(bool is_vtable_stub, int vtable_index) {
246 MutexLocker ml(VtableStubs_lock);
247 unsigned hash = VtableStubs::hash(is_vtable_stub, vtable_index);
248 VtableStub* s = _table[hash];
249 while( s && !s->matches(is_vtable_stub, vtable_index)) s = s->next();
250 return s;
251 }
252
253
254 void VtableStubs::enter(bool is_vtable_stub, int vtable_index, VtableStub* s) {
255 MutexLocker ml(VtableStubs_lock);
256 assert(s->matches(is_vtable_stub, vtable_index), "bad vtable stub");
257 unsigned int h = VtableStubs::hash(is_vtable_stub, vtable_index);
258 // enter s at the beginning of the corresponding list
259 s->set_next(_table[h]);
260 _table[h] = s;
261 _number_of_vtable_stubs++;
262 }
263
264 VtableStub* VtableStubs::entry_point(address pc) {
265 MutexLocker ml(VtableStubs_lock);
266 VtableStub* stub = (VtableStub*)(pc - VtableStub::entry_offset());
267 uint hash = VtableStubs::hash(stub->is_vtable_stub(), stub->index());
268 VtableStub* s;
269 for (s = _table[hash]; s != NULL && s != stub; s = s->next()) {}
270 return (s == stub) ? s : NULL;
271 }
272
273 bool VtableStubs::contains(address pc) {
274 // simple solution for now - we may want to use
275 // a faster way if this function is called often
276 return stub_containing(pc) != NULL;
277 }
278
279
280 VtableStub* VtableStubs::stub_containing(address pc) {
281 // Note: No locking needed since any change to the data structure
282 // happens with an atomic store into it (we don't care about
283 // consistency with the _number_of_vtable_stubs counter).
284 for (int i = 0; i < N; i++) {
285 for (VtableStub* s = _table[i]; s != NULL; s = s->next()) {
286 if (s->contains(pc)) return s;
287 }
288 }
289 return NULL;
290 }
291
292 void vtableStubs_init() {
293 VtableStubs::initialize();
294 }
295
296 void VtableStubs::vtable_stub_do(void f(VtableStub*)) {
297 for (int i = 0; i < N; i++) {
298 for (VtableStub* s = _table[i]; s != NULL; s = s->next()) {
299 f(s);
300 }
301 }
302 }
303
304
305 //-----------------------------------------------------------------------------------------------------
306 // Non-product code
307 #ifndef PRODUCT
308
309 extern "C" void bad_compiled_vtable_index(JavaThread* thread, oop receiver, int index) {
310 ResourceMark rm;
311 HandleMark hm;
312 Klass* klass = receiver->klass();
313 InstanceKlass* ik = InstanceKlass::cast(klass);
314 klassVtable vt = ik->vtable();
315 ik->print();
316 fatal("bad compiled vtable dispatch: receiver " INTPTR_FORMAT ", "
317 "index %d (vtable length %d)",
318 p2i(receiver), index, vt.length());
319 }
320
321 #endif // PRODUCT