1 /*
2 * Copyright (c) 1997, 2024, 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/codeBehaviours.hpp"
27 #include "code/codeCache.hpp"
28 #include "code/compiledIC.hpp"
29 #include "code/nmethod.hpp"
30 #include "code/vtableStubs.hpp"
31 #include "memory/resourceArea.hpp"
32 #include "memory/universe.hpp"
33 #include "oops/compressedKlass.hpp"
34 #include "oops/klass.inline.hpp"
35 #include "oops/method.inline.hpp"
36 #include "runtime/atomic.hpp"
37 #include "runtime/continuationEntry.hpp"
38 #include "runtime/handles.inline.hpp"
39 #include "runtime/interfaceSupport.inline.hpp"
40 #include "runtime/sharedRuntime.hpp"
41 #include "sanitizers/leak.hpp"
42
43
44 // Every time a compiled IC is changed or its type is being accessed,
45 // either the CompiledIC_lock must be set or we must be at a safe point.
46
47 CompiledICLocker::CompiledICLocker(nmethod* method)
48 : _method(method),
49 _behaviour(CompiledICProtectionBehaviour::current()),
50 _locked(_behaviour->lock(_method)) {
51 }
52
53 CompiledICLocker::~CompiledICLocker() {
54 if (_locked) {
55 _behaviour->unlock(_method);
56 }
57 }
58
59 bool CompiledICLocker::is_safe(nmethod* method) {
60 return CompiledICProtectionBehaviour::current()->is_safe(method);
61 }
62
63 bool CompiledICLocker::is_safe(address code) {
64 CodeBlob* cb = CodeCache::find_blob(code);
65 assert(cb != nullptr && cb->is_nmethod(), "must be compiled");
66 nmethod* nm = cb->as_nmethod();
67 return CompiledICProtectionBehaviour::current()->is_safe(nm);
68 }
69
70 CompiledICData::CompiledICData()
71 : _speculated_method(),
72 _speculated_klass(),
73 _itable_defc_klass(),
74 _itable_refc_klass(),
75 _is_initialized() {}
76
77 // Inline cache callsite info is initialized once the first time it is resolved
78 void CompiledICData::initialize(CallInfo* call_info, Klass* receiver_klass) {
79 _speculated_method = call_info->selected_method();
80 if (UseCompressedClassPointers) {
81 _speculated_klass = (uintptr_t)CompressedKlassPointers::encode_not_null(receiver_klass);
82 } else {
83 _speculated_klass = (uintptr_t)receiver_klass;
84 }
85 if (call_info->call_kind() == CallInfo::itable_call) {
86 assert(call_info->resolved_method() != nullptr, "virtual or interface method must be found");
87 _itable_defc_klass = call_info->resolved_method()->method_holder();
88 _itable_refc_klass = call_info->resolved_klass();
89 }
90 _is_initialized = true;
91 }
92
93 bool CompiledICData::is_speculated_klass_unloaded() const {
94 return is_initialized() && _speculated_klass == 0;
95 }
96
97 void CompiledICData::clean_metadata() {
98 if (!is_initialized() || is_speculated_klass_unloaded()) {
99 return;
100 }
101
102 // GC cleaning doesn't need to change the state of the inline cache,
103 // only nuke stale speculated metadata if it gets unloaded. If the
104 // inline cache is monomorphic, the unverified entries will miss, and
105 // subsequent miss handlers will upgrade the callsite to megamorphic,
106 // which makes sense as it obviously is megamorphic then.
107 if (!speculated_klass()->is_loader_alive()) {
108 Atomic::store(&_speculated_klass, (uintptr_t)0);
109 Atomic::store(&_speculated_method, (Method*)nullptr);
110 }
111
112 assert(_speculated_method == nullptr || _speculated_method->method_holder()->is_loader_alive(),
113 "Speculated method is not unloaded despite class being unloaded");
114 }
115
116 void CompiledICData::metadata_do(MetadataClosure* cl) {
117 if (!is_initialized()) {
118 return;
119 }
120
121 if (!is_speculated_klass_unloaded()) {
122 cl->do_metadata(_speculated_method);
123 cl->do_metadata(speculated_klass());
124 }
125 if (_itable_refc_klass != nullptr) {
126 cl->do_metadata(_itable_refc_klass);
127 }
128 if (_itable_defc_klass != nullptr) {
129 cl->do_metadata(_itable_defc_klass);
130 }
131 }
132
133 Klass* CompiledICData::speculated_klass() const {
134 if (is_speculated_klass_unloaded()) {
135 return nullptr;
136 }
137
138 if (UseCompressedClassPointers) {
139 return CompressedKlassPointers::decode_not_null((narrowKlass)_speculated_klass);
140 } else {
141 return (Klass*)_speculated_klass;
142 }
143 }
144
145 //-----------------------------------------------------------------------------
146 // High-level access to an inline cache. Guaranteed to be MT-safe.
147
148 CompiledICData* CompiledIC::data() const {
149 return _data;
150 }
151
152 CompiledICData* data_from_reloc_iter(RelocIterator* iter) {
153 assert(iter->type() == relocInfo::virtual_call_type, "wrong reloc. info");
154
155 virtual_call_Relocation* r = iter->virtual_call_reloc();
156 NativeMovConstReg* value = nativeMovConstReg_at(r->cached_value());
157
158 return (CompiledICData*)value->data();
159 }
160
161 CompiledIC::CompiledIC(RelocIterator* iter)
162 : _method(iter->code()),
163 _data(data_from_reloc_iter(iter)),
164 _call(nativeCall_at(iter->addr()))
165 {
166 assert(_method != nullptr, "must pass compiled method");
167 assert(_method->contains(iter->addr()), "must be in compiled method");
168 assert(CompiledICLocker::is_safe(_method), "mt unsafe call");
169 }
170
171 CompiledIC* CompiledIC_before(nmethod* nm, address return_addr) {
172 address call_site = nativeCall_before(return_addr)->instruction_address();
173 return CompiledIC_at(nm, call_site);
174 }
175
176 CompiledIC* CompiledIC_at(nmethod* nm, address call_site) {
177 RelocIterator iter(nm, call_site, call_site + 1);
178 iter.next();
179 return CompiledIC_at(&iter);
180 }
181
182 CompiledIC* CompiledIC_at(Relocation* call_reloc) {
183 address call_site = call_reloc->addr();
184 nmethod* nm = CodeCache::find_blob(call_reloc->addr())->as_nmethod();
185 return CompiledIC_at(nm, call_site);
186 }
187
188 CompiledIC* CompiledIC_at(RelocIterator* reloc_iter) {
189 CompiledIC* c_ic = new CompiledIC(reloc_iter);
190 c_ic->verify();
191 return c_ic;
192 }
193
194 void CompiledIC::ensure_initialized(CallInfo* call_info, Klass* receiver_klass) {
195 if (!_data->is_initialized()) {
196 _data->initialize(call_info, receiver_klass);
197 }
198 }
199
200 void CompiledIC::set_to_clean() {
201 log_debug(inlinecache)("IC@" INTPTR_FORMAT ": set to clean", p2i(_call->instruction_address()));
202 _call->set_destination_mt_safe(SharedRuntime::get_resolve_virtual_call_stub());
203 }
204
205 void CompiledIC::set_to_monomorphic() {
206 assert(data()->is_initialized(), "must be initialized");
207 Method* method = data()->speculated_method();
208 nmethod* code = method->code();
209 address entry;
210 bool to_compiled = code != nullptr && code->is_in_use() && !code->is_unloading();
211
212 if (to_compiled) {
213 entry = code->entry_point();
214 } else {
215 entry = method->get_c2i_unverified_entry();
216 }
217
218 log_trace(inlinecache)("IC@" INTPTR_FORMAT ": monomorphic to %s: %s",
219 p2i(_call->instruction_address()),
220 to_compiled ? "compiled" : "interpreter",
221 method->print_value_string());
222
223 _call->set_destination_mt_safe(entry);
224 }
225
226 void CompiledIC::set_to_megamorphic(CallInfo* call_info) {
227 assert(data()->is_initialized(), "must be initialized");
228
229 address entry;
230 if (call_info->call_kind() == CallInfo::direct_call) {
231 // C1 sometimes compiles a callsite before the target method is loaded, resulting in
232 // dynamically bound callsites that should really be statically bound. However, the
233 // target method might not have a vtable or itable. We just wait for better code to arrive
234 return;
235 } else if (call_info->call_kind() == CallInfo::itable_call) {
236 int itable_index = call_info->itable_index();
237 entry = VtableStubs::find_itable_stub(itable_index);
238 if (entry == nullptr) {
239 return;
240 }
241 #ifdef ASSERT
242 assert(call_info->resolved_method() != nullptr, "virtual or interface method must be found");
243 int index = call_info->resolved_method()->itable_index();
244 assert(index == itable_index, "CallInfo pre-computes this");
245 InstanceKlass* k = call_info->resolved_method()->method_holder();
246 assert(k->verify_itable_index(itable_index), "sanity check");
247 #endif //ASSERT
248 } else {
249 assert(call_info->call_kind() == CallInfo::vtable_call, "what else?");
250 // Can be different than selected_method->vtable_index(), due to package-private etc.
251 int vtable_index = call_info->vtable_index();
252 assert(call_info->resolved_klass()->verify_vtable_index(vtable_index), "sanity check");
253 entry = VtableStubs::find_vtable_stub(vtable_index);
254 if (entry == nullptr) {
255 return;
256 }
257 }
258
259 assert(call_info->selected_method() != nullptr, "virtual or interface method must be found");
260 log_trace(inlinecache)("IC@" INTPTR_FORMAT ": to megamorphic %s entry: " INTPTR_FORMAT,
261 p2i(_call->instruction_address()), call_info->selected_method()->print_value_string(), p2i(entry));
262
263 _call->set_destination_mt_safe(entry);
264 assert(is_megamorphic(), "sanity check");
265 }
266
267 void CompiledIC::update(CallInfo* call_info, Klass* receiver_klass) {
268 // If this is the first time we fix the inline cache, we ensure it's initialized
269 ensure_initialized(call_info, receiver_klass);
270
271 if (is_megamorphic()) {
272 // Terminal state for the inline cache
273 return;
274 }
275
276 if (is_speculated_klass(receiver_klass)) {
277 // If the speculated class matches the receiver klass, we can speculate that will
278 // continue to be the case with a monomorphic inline cache
279 set_to_monomorphic();
280 } else {
281 // If the dynamic type speculation fails, we try to transform to a megamorphic state
282 // for the inline cache using stubs to dispatch in tables
283 set_to_megamorphic(call_info);
284 }
285 }
286
287 bool CompiledIC::is_clean() const {
288 return destination() == SharedRuntime::get_resolve_virtual_call_stub();
289 }
290
291 bool CompiledIC::is_monomorphic() const {
292 return !is_clean() && !is_megamorphic();
293 }
294
295 bool CompiledIC::is_megamorphic() const {
296 return VtableStubs::entry_point(destination()) != nullptr;
297 }
298
299 bool CompiledIC::is_speculated_klass(Klass* receiver_klass) {
300 return data()->speculated_klass() == receiver_klass;
301 }
302
303 // GC support
304 void CompiledIC::clean_metadata() {
305 data()->clean_metadata();
306 }
307
308 void CompiledIC::metadata_do(MetadataClosure* cl) {
309 data()->metadata_do(cl);
310 }
311
312 #ifndef PRODUCT
313 void CompiledIC::print() {
314 tty->print("Inline cache at " INTPTR_FORMAT ", calling " INTPTR_FORMAT " cached_value " INTPTR_FORMAT,
315 p2i(instruction_address()), p2i(destination()), p2i(data()));
316 tty->cr();
317 }
318
319 void CompiledIC::verify() {
320 _call->verify();
321 }
322 #endif
323
324 // ----------------------------------------------------------------------------
325
326 void CompiledDirectCall::set_to_clean() {
327 // in_use is unused but needed to match template function in nmethod
328 assert(CompiledICLocker::is_safe(instruction_address()), "mt unsafe call");
329 // Reset call site
330 RelocIterator iter((nmethod*)nullptr, instruction_address(), instruction_address() + 1);
331 while (iter.next()) {
332 switch(iter.type()) {
333 case relocInfo::static_call_type:
334 _call->set_destination_mt_safe(SharedRuntime::get_resolve_static_call_stub());
335 break;
336 case relocInfo::opt_virtual_call_type:
337 _call->set_destination_mt_safe(SharedRuntime::get_resolve_opt_virtual_call_stub());
338 break;
339 default:
340 ShouldNotReachHere();
341 }
342 }
343 assert(is_clean(), "should be clean after cleaning");
344
345 log_debug(inlinecache)("DC@" INTPTR_FORMAT ": set to clean", p2i(_call->instruction_address()));
346 }
347
348 void CompiledDirectCall::set(const methodHandle& callee_method) {
349 nmethod* code = callee_method->code();
350 nmethod* caller = CodeCache::find_nmethod(instruction_address());
351 assert(caller != nullptr, "did not find caller nmethod");
352
353 bool to_interp_cont_enter = caller->method()->is_continuation_enter_intrinsic() &&
354 ContinuationEntry::is_interpreted_call(instruction_address());
355
356 bool to_compiled = !to_interp_cont_enter && code != nullptr && code->is_in_use() && !code->is_unloading();
357
358 if (to_compiled) {
359 _call->set_destination_mt_safe(code->verified_entry_point());
360 assert(is_call_to_compiled(), "should be compiled after set to compiled");
361 } else {
362 // Patch call site to C2I adapter if code is deoptimized or unloaded.
363 // We also need to patch the static call stub to set the rmethod register
364 // to the callee_method so the c2i adapter knows how to build the frame
365 set_to_interpreted(callee_method, callee_method->get_c2i_entry());
366 assert(is_call_to_interpreted(), "should be interpreted after set to interpreted");
367 }
368
369 log_trace(inlinecache)("DC@" INTPTR_FORMAT ": set to %s: %s: " INTPTR_FORMAT,
370 p2i(_call->instruction_address()),
371 to_compiled ? "compiled" : "interpreter",
372 callee_method->print_value_string(),
373 p2i(_call->destination()));
374 }
375
376 bool CompiledDirectCall::is_clean() const {
377 return destination() == SharedRuntime::get_resolve_static_call_stub() ||
378 destination() == SharedRuntime::get_resolve_opt_virtual_call_stub();
379 }
380
381 bool CompiledDirectCall::is_call_to_interpreted() const {
382 // It is a call to interpreted, if it calls to a stub. Hence, the destination
383 // must be in the stub part of the nmethod that contains the call
384 nmethod* nm = CodeCache::find_nmethod(instruction_address());
385 assert(nm != nullptr, "did not find nmethod");
386 return nm->stub_contains(destination());
387 }
388
389 bool CompiledDirectCall::is_call_to_compiled() const {
390 nmethod* caller = CodeCache::find_nmethod(instruction_address());
391 assert(caller != nullptr, "did not find caller nmethod");
392 CodeBlob* dest_cb = CodeCache::find_blob(destination());
393 return !caller->stub_contains(destination()) && dest_cb->is_nmethod();
394 }
395
396 address CompiledDirectCall::find_stub_for(address instruction) {
397 // Find reloc. information containing this call-site
398 RelocIterator iter((nmethod*)nullptr, instruction);
399 while (iter.next()) {
400 if (iter.addr() == instruction) {
401 switch(iter.type()) {
402 case relocInfo::static_call_type:
403 return iter.static_call_reloc()->static_stub();
404 // We check here for opt_virtual_call_type, since we reuse the code
405 // from the CompiledIC implementation
406 case relocInfo::opt_virtual_call_type:
407 return iter.opt_virtual_call_reloc()->static_stub();
408 default:
409 ShouldNotReachHere();
410 }
411 }
412 }
413 return nullptr;
414 }
415
416 address CompiledDirectCall::find_stub() {
417 return find_stub_for(instruction_address());
418 }
419
420 #ifndef PRODUCT
421 void CompiledDirectCall::print() {
422 tty->print("direct call at " INTPTR_FORMAT " to " INTPTR_FORMAT " -> ", p2i(instruction_address()), p2i(destination()));
423 if (is_clean()) {
424 tty->print("clean");
425 } else if (is_call_to_compiled()) {
426 tty->print("compiled");
427 } else if (is_call_to_interpreted()) {
428 tty->print("interpreted");
429 }
430 tty->cr();
431 }
432
433 void CompiledDirectCall::verify_mt_safe(const methodHandle& callee, address entry,
434 NativeMovConstReg* method_holder,
435 NativeJump* jump) {
436 _call->verify();
437 // A generated lambda form might be deleted from the Lambdaform
438 // cache in MethodTypeForm. If a jit compiled lambdaform method
439 // becomes not entrant and the cache access returns null, the new
440 // resolve will lead to a new generated LambdaForm.
441 Method* old_method = reinterpret_cast<Method*>(method_holder->data());
442 assert(old_method == nullptr || old_method == callee() ||
443 callee->is_compiled_lambda_form() ||
444 !old_method->method_holder()->is_loader_alive() ||
445 old_method->is_old(), // may be race patching deoptimized nmethod due to redefinition.
446 "a) MT-unsafe modification of inline cache");
447
448 address destination = jump->jump_destination();
449 assert(destination == (address)-1 || destination == entry
450 || old_method == nullptr || !old_method->method_holder()->is_loader_alive() // may have a race due to class unloading.
451 || old_method->is_old(), // may be race patching deoptimized nmethod due to redefinition.
452 "b) MT-unsafe modification of inline cache");
453 }
454 #endif