1/*
2 * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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.
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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
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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/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
48address VtableStub::_chunk = NULL;
49address VtableStub::_chunk_end = NULL;
50VMReg VtableStub::_receiver_location = VMRegImpl::Bad();
51
52
53void* 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
82void 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
87void VtableStub::print() const { print_on(tty); }
88
89// -----------------------------------------------------------------------------------------
90// Implementation of VtableStubs
91//
92// For each hash value there's a linked list of vtable stubs (with that
93// hash value). Each list is anchored in a little hash _table, indexed
94// by that hash value.
95
96VtableStub* VtableStubs::_table[VtableStubs::N];
97int VtableStubs::_number_of_vtable_stubs = 0;
98int VtableStubs::_vtab_stub_size = 0;
99int VtableStubs::_itab_stub_size = 0;
100
101#if defined(PRODUCT)
102 // These values are good for the PRODUCT case (no tracing).
103 static const int first_vtableStub_size = 64;
104 static const int first_itableStub_size = 256;
105#else
106 // These values are good for the non-PRODUCT case (when tracing can be switched on).
107 // To find out, run test workload with
108 // -Xlog:vtablestubs=Trace -XX:+CountCompiledCalls -XX:+DebugVtables
109 // and use the reported "estimate" value.
110 // Here is a list of observed worst-case values:
111 // vtable itable
112 // aarch64: 460 324
113 // arm: ? ?
114 // ppc (linux, BE): 404 288
115 // ppc (linux, LE): 356 276
116 // ppc (AIX): 416 296
117 // s390x: 408 256
118 // Solaris-sparc: 792 348
119 // x86 (Linux): 670 309
120 // x86 (MacOS): 682 321
121 static const int first_vtableStub_size = 1024;
122 static const int first_itableStub_size = 512;
123#endif
124
125
126void VtableStubs::initialize() {
127 VtableStub::_receiver_location = SharedRuntime::name_for_receiver();
128 {
129 MutexLocker ml(VtableStubs_lock, Mutex::_no_safepoint_check_flag);
130 assert(_number_of_vtable_stubs == 0, "potential performance bug: VtableStubs initialized more than once");
131 assert(is_power_of_2(N), "N must be a power of 2");
132 for (int i = 0; i < N; i++) {
133 _table[i] = NULL;
134 }
135 }
136}
137
138
139int VtableStubs::code_size_limit(bool is_vtable_stub) {
140 if (is_vtable_stub) {
141 return _vtab_stub_size > 0 ? _vtab_stub_size : first_vtableStub_size;
142 } else { // itable stub
143 return _itab_stub_size > 0 ? _itab_stub_size : first_itableStub_size;
144 }
145} // code_size_limit
146
147
148void VtableStubs::check_and_set_size_limit(bool is_vtable_stub,
149 int code_size,
150 int padding) {
151 const char* name = is_vtable_stub ? "vtable" : "itable";
152
153 guarantee(code_size <= code_size_limit(is_vtable_stub),
154 "buffer overflow in %s stub, code_size is %d, limit is %d", name, code_size, code_size_limit(is_vtable_stub));
155
156 if (is_vtable_stub) {
157 if (log_is_enabled(Trace, vtablestubs)) {
158 if ( (_vtab_stub_size > 0) && ((code_size + padding) > _vtab_stub_size) ) {
159 log_trace(vtablestubs)("%s size estimate needed adjustment from %d to %d bytes",
160 name, _vtab_stub_size, code_size + padding);
161 }
162 }
163 if ( (code_size + padding) > _vtab_stub_size ) {
164 _vtab_stub_size = code_size + padding;
165 }
166 } else { // itable stub
167 if (log_is_enabled(Trace, vtablestubs)) {
168 if ( (_itab_stub_size > 0) && ((code_size + padding) > _itab_stub_size) ) {
169 log_trace(vtablestubs)("%s size estimate needed adjustment from %d to %d bytes",
170 name, _itab_stub_size, code_size + padding);
171 }
172 }
173 if ( (code_size + padding) > _itab_stub_size ) {
174 _itab_stub_size = code_size + padding;
175 }
176 }
177 return;
178} // check_and_set_size_limit
179
180
181void VtableStubs::bookkeeping(MacroAssembler* masm, outputStream* out, VtableStub* s,
182 address npe_addr, address ame_addr, bool is_vtable_stub,
183 int index, int slop_bytes, int index_dependent_slop) {
184 const char* name = is_vtable_stub ? "vtable" : "itable";
185 const int stub_length = code_size_limit(is_vtable_stub);
186
187 if (log_is_enabled(Trace, vtablestubs)) {
188 log_trace(vtablestubs)("%s #%d at " PTR_FORMAT ": size: %d, estimate: %d, slop area: %d",
189 name, index, p2i(s->code_begin()),
190 (int)(masm->pc() - s->code_begin()),
191 stub_length,
192 (int)(s->code_end() - masm->pc()));
193 }
194 guarantee(masm->pc() <= s->code_end(), "%s #%d: overflowed buffer, estimated len: %d, actual len: %d, overrun: %d",
195 name, index, stub_length,
196 (int)(masm->pc() - s->code_begin()),
197 (int)(masm->pc() - s->code_end()));
198 assert((masm->pc() + index_dependent_slop) <= s->code_end(), "%s #%d: spare space for 32-bit offset: required = %d, available = %d",
199 name, index, index_dependent_slop,
200 (int)(s->code_end() - masm->pc()));
201
202 // After the first vtable/itable stub is generated, we have a much
203 // better estimate for the stub size. Remember/update this
204 // estimate after some sanity checks.
205 check_and_set_size_limit(is_vtable_stub, masm->offset(), slop_bytes);
206 s->set_exception_points(npe_addr, ame_addr);
207}
208
209
210address VtableStubs::find_stub(bool is_vtable_stub, int vtable_index) {
211 assert(vtable_index >= 0, "must be positive");
212
213 VtableStub* s;
214 {
215 MutexLocker ml(VtableStubs_lock, Mutex::_no_safepoint_check_flag);
216 s = ShareVtableStubs ? lookup(is_vtable_stub, vtable_index) : NULL;
217 if (s == NULL) {
218 if (is_vtable_stub) {
219 s = create_vtable_stub(vtable_index);
220 } else {
221 s = create_itable_stub(vtable_index);
222 }
223
224 // Creation of vtable or itable can fail if there is not enough free space in the code cache.
225 if (s == NULL) {
226 return NULL;
227 }
228
229 enter(is_vtable_stub, vtable_index, s);
230 if (PrintAdapterHandlers) {
231 tty->print_cr("Decoding VtableStub %s[%d]@" INTX_FORMAT,
232 is_vtable_stub? "vtbl": "itbl", vtable_index, p2i(VtableStub::receiver_location()));
233 Disassembler::decode(s->code_begin(), s->code_end());
234 }
235 // Notify JVMTI about this stub. The event will be recorded by the enclosing
236 // JvmtiDynamicCodeEventCollector and posted when this thread has released
237 // all locks.
238 if (JvmtiExport::should_post_dynamic_code_generated()) {
239 JvmtiExport::post_dynamic_code_generated_while_holding_locks(is_vtable_stub? "vtable stub": "itable stub",
240 s->code_begin(), s->code_end());
241 }
242 }
243 }
244 return s->entry_point();
245}
246
247
248inline uint VtableStubs::hash(bool is_vtable_stub, int vtable_index){
249 // Assumption: receiver_location < 4 in most cases.
250 int hash = ((vtable_index << 2) ^ VtableStub::receiver_location()->value()) + vtable_index;
251 return (is_vtable_stub ? ~hash : hash) & mask;
252}
253
254
255VtableStub* VtableStubs::lookup(bool is_vtable_stub, int vtable_index) {
256 assert_lock_strong(VtableStubs_lock);
257 unsigned hash = VtableStubs::hash(is_vtable_stub, vtable_index);
258 VtableStub* s = _table[hash];
259 while( s && !s->matches(is_vtable_stub, vtable_index)) s = s->next();
260 return s;
261}
262
263
264void VtableStubs::enter(bool is_vtable_stub, int vtable_index, VtableStub* s) {
265 assert_lock_strong(VtableStubs_lock);
266 assert(s->matches(is_vtable_stub, vtable_index), "bad vtable stub");
267 unsigned int h = VtableStubs::hash(is_vtable_stub, vtable_index);
268 // enter s at the beginning of the corresponding list
269 s->set_next(_table[h]);
270 _table[h] = s;
271 _number_of_vtable_stubs++;
272}
273
274VtableStub* VtableStubs::entry_point(address pc) {
275 MutexLocker ml(VtableStubs_lock, Mutex::_no_safepoint_check_flag);
276 VtableStub* stub = (VtableStub*)(pc - VtableStub::entry_offset());
277 uint hash = VtableStubs::hash(stub->is_vtable_stub(), stub->index());
278 VtableStub* s;
279 for (s = _table[hash]; s != NULL && s != stub; s = s->next()) {}
280 return (s == stub) ? s : NULL;
281}
282
283bool VtableStubs::contains(address pc) {
284 // simple solution for now - we may want to use
285 // a faster way if this function is called often
286 return stub_containing(pc) != NULL;
287}
288
289
290VtableStub* VtableStubs::stub_containing(address pc) {
291 // Note: No locking needed since any change to the data structure
292 // happens with an atomic store into it (we don't care about
293 // consistency with the _number_of_vtable_stubs counter).
294 for (int i = 0; i < N; i++) {
295 for (VtableStub* s = _table[i]; s != NULL; s = s->next()) {
296 if (s->contains(pc)) return s;
297 }
298 }
299 return NULL;
300}
301
302void vtableStubs_init() {
303 VtableStubs::initialize();
304}
305
306void VtableStubs::vtable_stub_do(void f(VtableStub*)) {
307 for (int i = 0; i < N; i++) {
308 for (VtableStub* s = _table[i]; s != NULL; s = s->next()) {
309 f(s);
310 }
311 }
312}
313
314
315//-----------------------------------------------------------------------------------------------------
316// Non-product code
317#ifndef PRODUCT
318
319extern "C" void bad_compiled_vtable_index(JavaThread* thread, oop receiver, int index) {
320 ResourceMark rm;
321 HandleMark hm;
322 Klass* klass = receiver->klass();
323 InstanceKlass* ik = InstanceKlass::cast(klass);
324 klassVtable vt = ik->vtable();
325 ik->print();
326 fatal("bad compiled vtable dispatch: receiver " INTPTR_FORMAT ", "
327 "index %d (vtable length %d)",
328 p2i(receiver), index, vt.length());
329}
330
331#endif // PRODUCT
332