1 /*
2 * Copyright (c) 1997, 2025, 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 "code/codeBehaviours.hpp"
26 #include "code/codeCache.hpp"
27 #include "code/compiledIC.hpp"
28 #include "code/nmethod.hpp"
29 #include "code/vtableStubs.hpp"
30 #include "memory/resourceArea.hpp"
31 #include "memory/universe.hpp"
32 #include "oops/compressedKlass.hpp"
33 #include "oops/klass.inline.hpp"
34 #include "oops/method.inline.hpp"
35 #include "runtime/atomic.hpp"
36 #include "runtime/continuationEntry.hpp"
37 #include "runtime/handles.inline.hpp"
38 #include "runtime/interfaceSupport.inline.hpp"
39 #include "runtime/sharedRuntime.hpp"
40 #include "sanitizers/leak.hpp"
41
42
43 // Every time a compiled IC is changed or its type is being accessed,
44 // either the CompiledIC_lock must be set or we must be at a safe point.
45
46 CompiledICLocker::CompiledICLocker(nmethod* method)
47 : _method(method),
48 _behaviour(CompiledICProtectionBehaviour::current()),
49 _locked(_behaviour->lock(_method)) {
50 }
51
52 CompiledICLocker::~CompiledICLocker() {
53 if (_locked) {
54 _behaviour->unlock(_method);
55 }
56 }
57
58 bool CompiledICLocker::is_safe(nmethod* method) {
59 return CompiledICProtectionBehaviour::current()->is_safe(method);
60 }
61
62 bool CompiledICLocker::is_safe(address code) {
63 CodeBlob* cb = CodeCache::find_blob(code);
64 assert(cb != nullptr && cb->is_nmethod(), "must be compiled");
65 nmethod* nm = cb->as_nmethod();
66 return CompiledICProtectionBehaviour::current()->is_safe(nm);
67 }
68
69 CompiledICData::CompiledICData()
70 : _speculated_method(),
71 _speculated_klass(),
72 _itable_defc_klass(),
73 _itable_refc_klass(),
74 _is_initialized() {}
75
76 // Inline cache callsite info is initialized once the first time it is resolved
77 void CompiledICData::initialize(CallInfo* call_info, Klass* receiver_klass) {
78 _speculated_method = call_info->selected_method();
79 if (UseCompressedClassPointers) {
80 _speculated_klass = (uintptr_t)CompressedKlassPointers::encode_not_null(receiver_klass);
81 } else {
82 _speculated_klass = (uintptr_t)receiver_klass;
83 }
84 if (call_info->call_kind() == CallInfo::itable_call) {
85 assert(call_info->resolved_method() != nullptr, "virtual or interface method must be found");
86 _itable_defc_klass = call_info->resolved_method()->method_holder();
87 _itable_refc_klass = call_info->resolved_klass();
88 }
89 _is_initialized = true;
90 }
91
92 bool CompiledICData::is_speculated_klass_unloaded() const {
93 return is_initialized() && _speculated_klass == 0;
94 }
95
96 void CompiledICData::clean_metadata() {
97 if (!is_initialized() || is_speculated_klass_unloaded()) {
98 return;
99 }
100
101 // GC cleaning doesn't need to change the state of the inline cache,
102 // only nuke stale speculated metadata if it gets unloaded. If the
103 // inline cache is monomorphic, the unverified entries will miss, and
104 // subsequent miss handlers will upgrade the callsite to megamorphic,
105 // which makes sense as it obviously is megamorphic then.
106 if (!speculated_klass()->is_loader_alive()) {
107 Atomic::store(&_speculated_klass, (uintptr_t)0);
108 Atomic::store(&_speculated_method, (Method*)nullptr);
109 }
110
111 assert(_speculated_method == nullptr || _speculated_method->method_holder()->is_loader_alive(),
112 "Speculated method is not unloaded despite class being unloaded");
113 }
114
115 void CompiledICData::metadata_do(MetadataClosure* cl) {
116 if (!is_initialized()) {
117 return;
118 }
119
120 if (!is_speculated_klass_unloaded()) {
121 cl->do_metadata(_speculated_method);
122 cl->do_metadata(speculated_klass());
123 }
124 if (_itable_refc_klass != nullptr) {
125 cl->do_metadata(_itable_refc_klass);
126 }
127 if (_itable_defc_klass != nullptr) {
128 cl->do_metadata(_itable_defc_klass);
129 }
130 }
131
132 Klass* CompiledICData::speculated_klass() const {
133 if (is_speculated_klass_unloaded()) {
134 return nullptr;
135 }
136
137 if (UseCompressedClassPointers) {
138 return CompressedKlassPointers::decode_not_null((narrowKlass)_speculated_klass);
139 } else {
140 return (Klass*)_speculated_klass;
141 }
142 }
143
144 //-----------------------------------------------------------------------------
145 // High-level access to an inline cache. Guaranteed to be MT-safe.
146
147 CompiledICData* CompiledIC::data() const {
148 return _data;
149 }
150
151 CompiledICData* data_from_reloc_iter(RelocIterator* iter) {
152 assert(iter->type() == relocInfo::virtual_call_type, "wrong reloc. info");
153
154 virtual_call_Relocation* r = iter->virtual_call_reloc();
155 NativeMovConstReg* value = nativeMovConstReg_at(r->cached_value());
156
157 return (CompiledICData*)value->data();
158 }
159
160 CompiledIC::CompiledIC(RelocIterator* iter)
161 : _method(iter->code()),
162 _data(data_from_reloc_iter(iter)),
163 _call(nativeCall_at(iter->addr()))
164 {
165 assert(_method != nullptr, "must pass compiled method");
166 assert(_method->contains(iter->addr()), "must be in compiled method");
167 assert(CompiledICLocker::is_safe(_method), "mt unsafe call");
168 }
169
170 CompiledIC* CompiledIC_before(nmethod* nm, address return_addr) {
171 address call_site = nativeCall_before(return_addr)->instruction_address();
172 return CompiledIC_at(nm, call_site);
173 }
174
175 CompiledIC* CompiledIC_at(nmethod* nm, address call_site) {
176 RelocIterator iter(nm, call_site, call_site + 1);
177 iter.next();
178 return CompiledIC_at(&iter);
179 }
180
181 CompiledIC* CompiledIC_at(Relocation* call_reloc) {
182 address call_site = call_reloc->addr();
183 nmethod* nm = CodeCache::find_blob(call_reloc->addr())->as_nmethod();
184 return CompiledIC_at(nm, call_site);
185 }
186
187 CompiledIC* CompiledIC_at(RelocIterator* reloc_iter) {
188 CompiledIC* c_ic = new CompiledIC(reloc_iter);
189 c_ic->verify();
190 return c_ic;
191 }
192
193 void CompiledIC::ensure_initialized(CallInfo* call_info, Klass* receiver_klass) {
194 if (!_data->is_initialized()) {
195 _data->initialize(call_info, receiver_klass);
196 }
197 }
198
199 void CompiledIC::set_to_clean() {
200 log_debug(inlinecache)("IC@" INTPTR_FORMAT ": set to clean", p2i(_call->instruction_address()));
201 _call->set_destination_mt_safe(SharedRuntime::get_resolve_virtual_call_stub());
202 }
203
204 void CompiledIC::set_to_monomorphic() {
205 assert(data()->is_initialized(), "must be initialized");
206 Method* method = data()->speculated_method();
207 nmethod* code = method->code();
208 address entry;
209 bool to_compiled = code != nullptr && code->is_in_use() && !code->is_unloading();
210
211 if (to_compiled) {
212 entry = code->entry_point();
213 } else {
214 entry = method->get_c2i_unverified_entry();
215 }
216
217 log_trace(inlinecache)("IC@" INTPTR_FORMAT ": monomorphic to %s: %s",
218 p2i(_call->instruction_address()),
219 to_compiled ? "compiled" : "interpreter",
220 method->print_value_string());
221
222 _call->set_destination_mt_safe(entry);
223 }
224
225 void CompiledIC::set_to_megamorphic(CallInfo* call_info) {
226 assert(data()->is_initialized(), "must be initialized");
227
228 address entry;
229 if (call_info->call_kind() == CallInfo::direct_call) {
230 // C1 sometimes compiles a callsite before the target method is loaded, resulting in
231 // dynamically bound callsites that should really be statically bound. However, the
232 // target method might not have a vtable or itable. We just wait for better code to arrive
233 return;
234 } else if (call_info->call_kind() == CallInfo::itable_call) {
235 int itable_index = call_info->itable_index();
236 entry = VtableStubs::find_itable_stub(itable_index);
237 if (entry == nullptr) {
238 return;
239 }
240 #ifdef ASSERT
241 assert(call_info->resolved_method() != nullptr, "virtual or interface method must be found");
242 int index = call_info->resolved_method()->itable_index();
243 assert(index == itable_index, "CallInfo pre-computes this");
244 InstanceKlass* k = call_info->resolved_method()->method_holder();
245 assert(k->verify_itable_index(itable_index), "sanity check");
246 #endif //ASSERT
247 } else {
248 assert(call_info->call_kind() == CallInfo::vtable_call, "what else?");
249 // Can be different than selected_method->vtable_index(), due to package-private etc.
250 int vtable_index = call_info->vtable_index();
251 assert(call_info->resolved_klass()->verify_vtable_index(vtable_index), "sanity check");
252 entry = VtableStubs::find_vtable_stub(vtable_index);
253 if (entry == nullptr) {
254 return;
255 }
256 }
257
258 assert(call_info->selected_method() != nullptr, "virtual or interface method must be found");
259 log_trace(inlinecache)("IC@" INTPTR_FORMAT ": to megamorphic %s entry: " INTPTR_FORMAT,
260 p2i(_call->instruction_address()), call_info->selected_method()->print_value_string(), p2i(entry));
261
262 _call->set_destination_mt_safe(entry);
263 assert(is_megamorphic(), "sanity check");
264 }
265
266 void CompiledIC::update(CallInfo* call_info, Klass* receiver_klass) {
267 // If this is the first time we fix the inline cache, we ensure it's initialized
268 ensure_initialized(call_info, receiver_klass);
269
270 if (is_megamorphic()) {
271 // Terminal state for the inline cache
272 return;
273 }
274
275 if (is_speculated_klass(receiver_klass)) {
276 // If the speculated class matches the receiver klass, we can speculate that will
277 // continue to be the case with a monomorphic inline cache
278 set_to_monomorphic();
279 } else {
280 // If the dynamic type speculation fails, we try to transform to a megamorphic state
281 // for the inline cache using stubs to dispatch in tables
282 set_to_megamorphic(call_info);
283 }
284 }
285
286 bool CompiledIC::is_clean() const {
287 return destination() == SharedRuntime::get_resolve_virtual_call_stub();
288 }
289
290 bool CompiledIC::is_monomorphic() const {
291 return !is_clean() && !is_megamorphic();
292 }
293
294 bool CompiledIC::is_megamorphic() const {
295 return VtableStubs::entry_point(destination()) != nullptr;
296 }
297
298 bool CompiledIC::is_speculated_klass(Klass* receiver_klass) {
299 return data()->speculated_klass() == receiver_klass;
300 }
301
302 // GC support
303 void CompiledIC::clean_metadata() {
304 data()->clean_metadata();
305 }
306
307 void CompiledIC::metadata_do(MetadataClosure* cl) {
308 data()->metadata_do(cl);
309 }
310
311 #ifndef PRODUCT
312 void CompiledIC::print() {
313 tty->print("Inline cache at " INTPTR_FORMAT ", calling " INTPTR_FORMAT " cached_value " INTPTR_FORMAT,
314 p2i(instruction_address()), p2i(destination()), p2i(data()));
315 tty->cr();
316 }
317
318 void CompiledIC::verify() {
319 _call->verify();
320 }
321 #endif
322
323 // ----------------------------------------------------------------------------
324
325 void CompiledDirectCall::set_to_clean() {
326 // in_use is unused but needed to match template function in nmethod
327 assert(CompiledICLocker::is_safe(instruction_address()), "mt unsafe call");
328 // Reset call site
329 RelocIterator iter((nmethod*)nullptr, instruction_address(), instruction_address() + 1);
330 while (iter.next()) {
331 switch(iter.type()) {
332 case relocInfo::static_call_type:
333 _call->set_destination_mt_safe(SharedRuntime::get_resolve_static_call_stub());
334 break;
335 case relocInfo::opt_virtual_call_type:
336 _call->set_destination_mt_safe(SharedRuntime::get_resolve_opt_virtual_call_stub());
337 break;
338 default:
339 ShouldNotReachHere();
340 }
341 }
342 assert(is_clean(), "should be clean after cleaning");
343
344 log_debug(inlinecache)("DC@" INTPTR_FORMAT ": set to clean", p2i(_call->instruction_address()));
345 }
346
347 void CompiledDirectCall::set(const methodHandle& callee_method) {
348 nmethod* code = callee_method->code();
349 nmethod* caller = CodeCache::find_nmethod(instruction_address());
350 assert(caller != nullptr, "did not find caller nmethod");
351
352 bool to_interp_cont_enter = caller->method()->is_continuation_enter_intrinsic() &&
353 ContinuationEntry::is_interpreted_call(instruction_address());
354
355 bool to_compiled = !to_interp_cont_enter && code != nullptr && code->is_in_use() && !code->is_unloading();
356
357 if (to_compiled) {
358 _call->set_destination_mt_safe(code->verified_entry_point());
359 assert(is_call_to_compiled(), "should be compiled after set to compiled");
360 } else {
361 // Patch call site to C2I adapter if code is deoptimized or unloaded.
362 // We also need to patch the static call stub to set the rmethod register
363 // to the callee_method so the c2i adapter knows how to build the frame
364 set_to_interpreted(callee_method, callee_method->get_c2i_entry());
365 assert(is_call_to_interpreted(), "should be interpreted after set to interpreted");
366 }
367
368 log_trace(inlinecache)("DC@" INTPTR_FORMAT ": set to %s: %s: " INTPTR_FORMAT,
369 p2i(_call->instruction_address()),
370 to_compiled ? "compiled" : "interpreter",
371 callee_method->print_value_string(),
372 p2i(_call->destination()));
373 }
374
375 bool CompiledDirectCall::is_clean() const {
376 return destination() == SharedRuntime::get_resolve_static_call_stub() ||
377 destination() == SharedRuntime::get_resolve_opt_virtual_call_stub();
378 }
379
380 bool CompiledDirectCall::is_call_to_interpreted() const {
381 // It is a call to interpreted, if it calls to a stub. Hence, the destination
382 // must be in the stub part of the nmethod that contains the call
383 nmethod* nm = CodeCache::find_nmethod(instruction_address());
384 assert(nm != nullptr, "did not find nmethod");
385 return nm->stub_contains(destination());
386 }
387
388 bool CompiledDirectCall::is_call_to_compiled() const {
389 nmethod* caller = CodeCache::find_nmethod(instruction_address());
390 assert(caller != nullptr, "did not find caller nmethod");
391 CodeBlob* dest_cb = CodeCache::find_blob(destination());
392 return !caller->stub_contains(destination()) && dest_cb->is_nmethod();
393 }
394
395 address CompiledDirectCall::find_stub_for(address instruction) {
396 // Find reloc. information containing this call-site
397 RelocIterator iter((nmethod*)nullptr, instruction);
398 while (iter.next()) {
399 if (iter.addr() == instruction) {
400 switch(iter.type()) {
401 case relocInfo::static_call_type:
402 return iter.static_call_reloc()->static_stub();
403 // We check here for opt_virtual_call_type, since we reuse the code
404 // from the CompiledIC implementation
405 case relocInfo::opt_virtual_call_type:
406 return iter.opt_virtual_call_reloc()->static_stub();
407 default:
408 ShouldNotReachHere();
409 }
410 }
411 }
412 return nullptr;
413 }
414
415 address CompiledDirectCall::find_stub() {
416 return find_stub_for(instruction_address());
417 }
418
419 #ifndef PRODUCT
420 void CompiledDirectCall::print() {
421 tty->print("direct call at " INTPTR_FORMAT " to " INTPTR_FORMAT " -> ", p2i(instruction_address()), p2i(destination()));
422 if (is_clean()) {
423 tty->print("clean");
424 } else if (is_call_to_compiled()) {
425 tty->print("compiled");
426 } else if (is_call_to_interpreted()) {
427 tty->print("interpreted");
428 }
429 tty->cr();
430 }
431
432 void CompiledDirectCall::verify_mt_safe(const methodHandle& callee, address entry,
433 NativeMovConstReg* method_holder,
434 NativeJump* jump) {
435 _call->verify();
436 // A generated lambda form might be deleted from the Lambdaform
437 // cache in MethodTypeForm. If a jit compiled lambdaform method
438 // becomes not entrant and the cache access returns null, the new
439 // resolve will lead to a new generated LambdaForm.
440 Method* old_method = reinterpret_cast<Method*>(method_holder->data());
441 assert(old_method == nullptr || old_method == callee() ||
442 callee->is_compiled_lambda_form() ||
443 !old_method->method_holder()->is_loader_alive() ||
444 old_method->is_old(), // may be race patching deoptimized nmethod due to redefinition.
445 "a) MT-unsafe modification of inline cache");
446
447 address destination = jump->jump_destination();
448 assert(destination == (address)-1 || destination == entry
449 || old_method == nullptr || !old_method->method_holder()->is_loader_alive() // may have a race due to class unloading.
450 || old_method->is_old(), // may be race patching deoptimized nmethod due to redefinition.
451 "b) MT-unsafe modification of inline cache");
452 }
453 #endif