1 /*
2 * Copyright (c) 1997, 2023, 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.
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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/klass.inline.hpp"
34 #include "oops/klassVtable.hpp"
35 #include "oops/oop.inline.hpp"
36 #include "prims/forte.hpp"
37 #include "prims/jvmtiExport.hpp"
38 #include "runtime/handles.inline.hpp"
39 #include "runtime/mutexLocker.hpp"
40 #include "runtime/sharedRuntime.hpp"
41 #include "utilities/align.hpp"
42 #include "utilities/powerOfTwo.hpp"
43 #ifdef COMPILER2
44 #include "opto/matcher.hpp"
45 #endif
46
47 // -----------------------------------------------------------------------------------------
48 // Implementation of VtableStub
49
50 address VtableStub::_chunk = nullptr;
51 address VtableStub::_chunk_end = nullptr;
52 VMReg VtableStub::_receiver_location = VMRegImpl::Bad();
53
54
55 void* VtableStub::operator new(size_t size, int code_size) throw() {
56 assert_lock_strong(VtableStubs_lock);
57 assert(size == sizeof(VtableStub), "mismatched size");
58 // compute real VtableStub size (rounded to nearest word)
59 const int real_size = align_up(code_size + (int)sizeof(VtableStub), wordSize);
60 // malloc them in chunks to minimize header overhead
61 const int chunk_factor = 32;
62 if (_chunk == nullptr || _chunk + real_size > _chunk_end) {
63 const int bytes = chunk_factor * real_size + pd_code_alignment();
64
65 // There is a dependency on the name of the blob in src/share/vm/prims/jvmtiCodeBlobEvents.cpp
66 // If changing the name, update the other file accordingly.
67 VtableBlob* blob = VtableBlob::create("vtable chunks", bytes);
68 if (blob == nullptr) {
69 return nullptr;
70 }
71 _chunk = blob->content_begin();
72 _chunk_end = _chunk + bytes;
73 Forte::register_stub("vtable stub", _chunk, _chunk_end);
74 align_chunk();
75 }
76 assert(_chunk + real_size <= _chunk_end, "bad allocation");
77 void* res = _chunk;
78 _chunk += real_size;
79 align_chunk();
80 return res;
81 }
82
83
84 void VtableStub::print_on(outputStream* st) const {
85 st->print("vtable stub (index = %d, receiver_location = " INTX_FORMAT ", code = [" INTPTR_FORMAT ", " INTPTR_FORMAT "])",
86 index(), p2i(receiver_location()), p2i(code_begin()), p2i(code_end()));
87 }
88
89 void VtableStub::print() const { print_on(tty); }
90
91 // -----------------------------------------------------------------------------------------
92 // Implementation of VtableStubs
93 //
94 // For each hash value there's a linked list of vtable stubs (with that
95 // hash value). Each list is anchored in a little hash _table, indexed
96 // by that hash value.
97
98 VtableStub* VtableStubs::_table[VtableStubs::N];
99 int VtableStubs::_number_of_vtable_stubs = 0;
100 int VtableStubs::_vtab_stub_size = 0;
101 int VtableStubs::_itab_stub_size = 0;
102
103 #if defined(PRODUCT)
104 // These values are good for the PRODUCT case (no tracing).
105 static const int first_vtableStub_size = 256;
106 static const int first_itableStub_size = 512;
107 #else
108 // These values are good for the non-PRODUCT case (when tracing can be switched on).
109 // To find out, run test workload with
110 // -Xlog:vtablestubs=Trace -XX:+CountCompiledCalls -XX:+DebugVtables
111 // and use the reported "estimate" value.
112 // Here is a list of observed worst-case values:
113 // vtable itable
114 // aarch64: 460 324
115 // arm: ? ?
116 // ppc (linux, BE): 404 288
117 // ppc (linux, LE): 356 276
118 // ppc (AIX): 416 296
119 // s390x: 408 256
120 // Solaris-sparc: 792 348
121 // x86 (Linux): 670 309
122 // x86 (MacOS): 682 321
123 static const int first_vtableStub_size = 1024;
124 static const int first_itableStub_size = 512;
125 #endif
126
127
128 void VtableStubs::initialize() {
129 VtableStub::_receiver_location = SharedRuntime::name_for_receiver();
130 {
131 MutexLocker ml(VtableStubs_lock, Mutex::_no_safepoint_check_flag);
132 assert(_number_of_vtable_stubs == 0, "potential performance bug: VtableStubs initialized more than once");
133 assert(is_power_of_2(int(N)), "N must be a power of 2");
134 for (int i = 0; i < N; i++) {
135 _table[i] = nullptr;
136 }
137 }
138 }
139
140
141 int VtableStubs::code_size_limit(bool is_vtable_stub) {
142 if (is_vtable_stub) {
143 return _vtab_stub_size > 0 ? _vtab_stub_size : first_vtableStub_size;
144 } else { // itable stub
145 return _itab_stub_size > 0 ? _itab_stub_size : first_itableStub_size;
146 }
147 } // code_size_limit
148
149
150 void VtableStubs::check_and_set_size_limit(bool is_vtable_stub,
151 int code_size,
152 int padding) {
153 const char* name = is_vtable_stub ? "vtable" : "itable";
154
155 guarantee(code_size <= code_size_limit(is_vtable_stub),
156 "buffer overflow in %s stub, code_size is %d, limit is %d", name, code_size, code_size_limit(is_vtable_stub));
157
158 if (is_vtable_stub) {
159 if (log_is_enabled(Trace, vtablestubs)) {
160 if ( (_vtab_stub_size > 0) && ((code_size + padding) > _vtab_stub_size) ) {
161 log_trace(vtablestubs)("%s size estimate needed adjustment from %d to %d bytes",
162 name, _vtab_stub_size, code_size + padding);
163 }
164 }
165 if ( (code_size + padding) > _vtab_stub_size ) {
166 _vtab_stub_size = code_size + padding;
167 }
168 } else { // itable stub
169 if (log_is_enabled(Trace, vtablestubs)) {
170 if ( (_itab_stub_size > 0) && ((code_size + padding) > _itab_stub_size) ) {
171 log_trace(vtablestubs)("%s size estimate needed adjustment from %d to %d bytes",
172 name, _itab_stub_size, code_size + padding);
173 }
174 }
175 if ( (code_size + padding) > _itab_stub_size ) {
176 _itab_stub_size = code_size + padding;
177 }
178 }
179 return;
180 } // check_and_set_size_limit
181
182
183 void VtableStubs::bookkeeping(MacroAssembler* masm, outputStream* out, VtableStub* s,
184 address npe_addr, address ame_addr, bool is_vtable_stub,
185 int index, int slop_bytes, int index_dependent_slop) {
186 const char* name = is_vtable_stub ? "vtable" : "itable";
187 const int stub_length = code_size_limit(is_vtable_stub);
188
189 if (log_is_enabled(Trace, vtablestubs)) {
190 log_trace(vtablestubs)("%s #%d at " PTR_FORMAT ": size: %d, estimate: %d, slop area: %d",
191 name, index, p2i(s->code_begin()),
192 (int)(masm->pc() - s->code_begin()),
193 stub_length,
194 (int)(s->code_end() - masm->pc()));
195 }
196 guarantee(masm->pc() <= s->code_end(), "%s #%d: overflowed buffer, estimated len: %d, actual len: %d, overrun: %d",
197 name, index, stub_length,
198 (int)(masm->pc() - s->code_begin()),
199 (int)(masm->pc() - s->code_end()));
200 assert((masm->pc() + index_dependent_slop) <= s->code_end(), "%s #%d: spare space for 32-bit offset: required = %d, available = %d",
201 name, index, index_dependent_slop,
202 (int)(s->code_end() - masm->pc()));
203
204 // After the first vtable/itable stub is generated, we have a much
205 // better estimate for the stub size. Remember/update this
206 // estimate after some sanity checks.
207 check_and_set_size_limit(is_vtable_stub, masm->offset(), slop_bytes);
208 s->set_exception_points(npe_addr, ame_addr);
209 }
210
211
212 address VtableStubs::find_stub(bool is_vtable_stub, int vtable_index) {
213 assert(vtable_index >= 0, "must be positive");
214
215 VtableStub* s;
216 {
217 MutexLocker ml(VtableStubs_lock, Mutex::_no_safepoint_check_flag);
218 s = lookup(is_vtable_stub, vtable_index);
219 if (s == nullptr) {
220 if (is_vtable_stub) {
221 s = create_vtable_stub(vtable_index);
222 } else {
223 s = create_itable_stub(vtable_index);
224 }
225
226 // Creation of vtable or itable can fail if there is not enough free space in the code cache.
227 if (s == nullptr) {
228 return nullptr;
229 }
230
231 enter(is_vtable_stub, vtable_index, s);
232 if (PrintAdapterHandlers) {
233 tty->print_cr("Decoding VtableStub %s[%d]@" INTX_FORMAT,
234 is_vtable_stub? "vtbl": "itbl", vtable_index, p2i(VtableStub::receiver_location()));
235 Disassembler::decode(s->code_begin(), s->code_end());
236 }
237 // Notify JVMTI about this stub. The event will be recorded by the enclosing
238 // JvmtiDynamicCodeEventCollector and posted when this thread has released
239 // all locks. Only post this event if a new state is not required. Creating a new state would
240 // cause a safepoint and the caller of this code has a NoSafepointVerifier.
241 if (JvmtiExport::should_post_dynamic_code_generated()) {
242 JvmtiExport::post_dynamic_code_generated_while_holding_locks(is_vtable_stub? "vtable stub": "itable stub",
243 s->code_begin(), s->code_end());
244 }
245 }
246 }
247 return s->entry_point();
248 }
249
250
251 inline uint VtableStubs::hash(bool is_vtable_stub, int vtable_index){
252 // Assumption: receiver_location < 4 in most cases.
253 int hash = ((vtable_index << 2) ^ VtableStub::receiver_location()->value()) + vtable_index;
254 return (is_vtable_stub ? ~hash : hash) & mask;
255 }
256
257
258 VtableStub* VtableStubs::lookup(bool is_vtable_stub, int vtable_index) {
259 assert_lock_strong(VtableStubs_lock);
260 unsigned hash = VtableStubs::hash(is_vtable_stub, vtable_index);
261 VtableStub* s = _table[hash];
262 while( s && !s->matches(is_vtable_stub, vtable_index)) s = s->next();
263 return s;
264 }
265
266
267 void VtableStubs::enter(bool is_vtable_stub, int vtable_index, VtableStub* s) {
268 assert_lock_strong(VtableStubs_lock);
269 assert(s->matches(is_vtable_stub, vtable_index), "bad vtable stub");
270 unsigned int h = VtableStubs::hash(is_vtable_stub, vtable_index);
271 // enter s at the beginning of the corresponding list
272 s->set_next(_table[h]);
273 _table[h] = s;
274 _number_of_vtable_stubs++;
275 }
276
277 VtableStub* VtableStubs::entry_point(address pc) {
278 MutexLocker ml(VtableStubs_lock, Mutex::_no_safepoint_check_flag);
279 VtableStub* stub = (VtableStub*)(pc - VtableStub::entry_offset());
280 uint hash = VtableStubs::hash(stub->is_vtable_stub(), stub->index());
281 VtableStub* s;
282 for (s = _table[hash]; s != nullptr && s != stub; s = s->next()) {}
283 return (s == stub) ? s : nullptr;
284 }
285
286 bool VtableStubs::contains(address pc) {
287 // simple solution for now - we may want to use
288 // a faster way if this function is called often
289 return stub_containing(pc) != nullptr;
290 }
291
292
293 VtableStub* VtableStubs::stub_containing(address pc) {
294 // Note: No locking needed since any change to the data structure
295 // happens with an atomic store into it (we don't care about
296 // consistency with the _number_of_vtable_stubs counter).
297 for (int i = 0; i < N; i++) {
298 for (VtableStub* s = _table[i]; s != nullptr; s = s->next()) {
299 if (s->contains(pc)) return s;
300 }
301 }
302 return nullptr;
303 }
304
305 void vtableStubs_init() {
306 VtableStubs::initialize();
307 }
308
309 void VtableStubs::vtable_stub_do(void f(VtableStub*)) {
310 for (int i = 0; i < N; i++) {
311 for (VtableStub* s = _table[i]; s != nullptr; s = s->next()) {
312 f(s);
313 }
314 }
315 }
316
317
318 //-----------------------------------------------------------------------------------------------------
319 // Non-product code
320 #ifndef PRODUCT
321
322 extern "C" void bad_compiled_vtable_index(JavaThread* thread, oop receiver, int index) {
323 ResourceMark rm;
324 Klass* klass = receiver->klass();
325 InstanceKlass* ik = InstanceKlass::cast(klass);
326 klassVtable vt = ik->vtable();
327 ik->print();
328 fatal("bad compiled vtable dispatch: receiver " INTPTR_FORMAT ", "
329 "index %d (vtable length %d)",
330 p2i(receiver), index, vt.length());
331 }
332
333 #endif // PRODUCT