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/debugInfo.hpp"
 26 #include "code/debugInfoRec.hpp"
 27 #include "code/nmethod.hpp"
 28 #include "gc/shared/collectedHeap.hpp"
 29 #include "memory/universe.hpp"
 30 #include "oops/oop.inline.hpp"
 31 #include "runtime/stackValue.hpp"
 32 #include "runtime/handles.inline.hpp"
 33 #include "runtime/interfaceSupport.inline.hpp"
 34 #include "runtime/javaThread.hpp"
 35 #include "runtime/jniHandles.inline.hpp"
 36 
 37 // Constructors
 38 
 39 DebugInfoWriteStream::DebugInfoWriteStream(DebugInformationRecorder* recorder, int initial_size)
 40 : CompressedWriteStream(initial_size) {
 41   _recorder = recorder;
 42 }
 43 
 44 // Serializing oops
 45 
 46 void DebugInfoWriteStream::write_handle(jobject h) {
 47   write_int(recorder()->oop_recorder()->find_index(h));
 48 }
 49 
 50 void DebugInfoWriteStream::write_metadata(Metadata* h) {
 51   write_int(recorder()->oop_recorder()->find_index(h));
 52 }
 53 
 54 oop DebugInfoReadStream::read_oop() {
 55   // Despite these oops being found inside nmethods that are on-stack,
 56   // they are not kept alive by all GCs (e.g. G1 and Shenandoah).
 57   oop o = code()->oop_at_phantom(read_int());
 58   assert(oopDesc::is_oop_or_null(o), "oop only");
 59   return o;
 60 }
 61 
 62 ScopeValue* DebugInfoReadStream::read_object_value(bool is_auto_box) {
 63   int id = read_int();
 64 #ifdef ASSERT
 65   assert(_obj_pool != nullptr, "object pool does not exist");
 66   for (int i = _obj_pool->length() - 1; i >= 0; i--) {
 67     assert(_obj_pool->at(i)->as_ObjectValue()->id() != id, "should not be read twice");
 68   }
 69 #endif
 70   ObjectValue* result = is_auto_box ? new AutoBoxObjectValue(id) : new ObjectValue(id);
 71   // Cache the object since an object field could reference it.
 72   _obj_pool->push(result);
 73   result->read_object(this);
 74   return result;
 75 }
 76 
 77 ScopeValue* DebugInfoReadStream::read_object_merge_value() {
 78   int id = read_int();
 79 #ifdef ASSERT
 80   assert(_obj_pool != nullptr, "object pool does not exist");
 81   for (int i = _obj_pool->length() - 1; i >= 0; i--) {
 82     assert(_obj_pool->at(i)->as_ObjectValue()->id() != id, "should not be read twice");
 83   }
 84 #endif
 85   ObjectMergeValue* result = new ObjectMergeValue(id);
 86   _obj_pool->push(result);
 87   result->read_object(this);
 88   return result;
 89 }
 90 
 91 ScopeValue* DebugInfoReadStream::get_cached_object() {
 92   int id = read_int();
 93   assert(_obj_pool != nullptr, "object pool does not exist");
 94   for (int i = _obj_pool->length() - 1; i >= 0; i--) {
 95     ObjectValue* ov = _obj_pool->at(i)->as_ObjectValue();
 96     if (ov->id() == id) {
 97       return ov;
 98     }
 99   }
100   ShouldNotReachHere();
101   return nullptr;
102 }
103 
104 // Serializing scope values
105 
106 enum { LOCATION_CODE = 0, CONSTANT_INT_CODE = 1,  CONSTANT_OOP_CODE = 2,
107                           CONSTANT_LONG_CODE = 3, CONSTANT_DOUBLE_CODE = 4,
108                           OBJECT_CODE = 5,        OBJECT_ID_CODE = 6,
109                           AUTO_BOX_OBJECT_CODE = 7, MARKER_CODE = 8,
110                           OBJECT_MERGE_CODE = 9 };
111 
112 ScopeValue* ScopeValue::read_from(DebugInfoReadStream* stream) {
113   ScopeValue* result = nullptr;
114   switch(stream->read_int()) {
115    case LOCATION_CODE:        result = new LocationValue(stream);                        break;
116    case CONSTANT_INT_CODE:    result = new ConstantIntValue(stream);                     break;
117    case CONSTANT_OOP_CODE:    result = new ConstantOopReadValue(stream);                 break;
118    case CONSTANT_LONG_CODE:   result = new ConstantLongValue(stream);                    break;
119    case CONSTANT_DOUBLE_CODE: result = new ConstantDoubleValue(stream);                  break;
120    case OBJECT_CODE:          result = stream->read_object_value(false /*is_auto_box*/); break;
121    case AUTO_BOX_OBJECT_CODE: result = stream->read_object_value(true /*is_auto_box*/);  break;
122    case OBJECT_MERGE_CODE:    result = stream->read_object_merge_value();                break;
123    case OBJECT_ID_CODE:       result = stream->get_cached_object();                      break;
124    case MARKER_CODE:          result = new MarkerValue();                                break;
125    default: ShouldNotReachHere();
126   }
127   return result;
128 }
129 
130 // LocationValue
131 
132 LocationValue::LocationValue(DebugInfoReadStream* stream) {
133   _location = Location(stream);
134 }
135 
136 void LocationValue::write_on(DebugInfoWriteStream* stream) {
137   stream->write_int(LOCATION_CODE);
138   location().write_on(stream);
139 }
140 
141 void LocationValue::print_on(outputStream* st) const {
142   location().print_on(st);
143 }
144 
145 // MarkerValue
146 
147 void MarkerValue::write_on(DebugInfoWriteStream* stream) {
148   stream->write_int(MARKER_CODE);
149 }
150 
151 void MarkerValue::print_on(outputStream* st) const {
152     st->print("marker");
153 }
154 
155 // ObjectValue
156 
157 void ObjectValue::set_value(oop value) {
158   _value = Handle(Thread::current(), value);
159 }
160 
161 void ObjectValue::read_object(DebugInfoReadStream* stream) {
162   _is_root = stream->read_bool();
163   _klass = read_from(stream);
164   _properties = read_from(stream);
165   assert(_klass->is_constant_oop(), "should be constant java mirror oop");
166   int length = stream->read_int();
167   for (int i = 0; i < length; i++) {
168     ScopeValue* val = read_from(stream);
169     _field_values.append(val);
170   }
171 }
172 
173 void ObjectValue::write_on(DebugInfoWriteStream* stream) {
174   if (is_visited()) {
175     stream->write_int(OBJECT_ID_CODE);
176     stream->write_int(_id);
177   } else {
178     set_visited(true);
179     stream->write_int(is_auto_box() ? AUTO_BOX_OBJECT_CODE : OBJECT_CODE);
180     stream->write_int(_id);
181     stream->write_bool(_is_root);
182     _klass->write_on(stream);
183     _properties->write_on(stream);
184     int length = _field_values.length();
185     stream->write_int(length);
186     for (int i = 0; i < length; i++) {
187       _field_values.at(i)->write_on(stream);
188     }
189   }
190 }
191 
192 void ObjectValue::print_on(outputStream* st) const {
193   st->print("%s[%d]", is_auto_box() ? "box_obj" : is_object_merge() ? "merge_obj" : "obj", _id);
194 }
195 
196 void ObjectValue::print_fields_on(outputStream* st) const {
197 #ifndef PRODUCT
198   if (is_object_merge()) {
199     ObjectMergeValue* omv = (ObjectMergeValue*)this;
200     st->print("selector=\"");
201     omv->selector()->print_on(st);
202     st->print("\"");
203     ScopeValue* merge_pointer = omv->merge_pointer();
204     if (!(merge_pointer->is_object() && merge_pointer->as_ObjectValue()->value()() == nullptr) &&
205         !(merge_pointer->is_constant_oop() && merge_pointer->as_ConstantOopReadValue()->value()() == nullptr)) {
206       st->print(", merge_pointer=\"");
207       merge_pointer->print_on(st);
208       st->print("\"");
209     }
210     GrowableArray<ScopeValue*>* possible_objects = omv->possible_objects();
211     st->print(", candidate_objs=[%d", possible_objects->at(0)->as_ObjectValue()->id());
212     int ncandidates = possible_objects->length();
213     for (int i = 1; i < ncandidates; i++) {
214       st->print(", %d", possible_objects->at(i)->as_ObjectValue()->id());
215     }
216     st->print("]");
217   } else {
218     st->print("\n        Fields: ");
219     if (_field_values.length() > 0) {
220       _field_values.at(0)->print_on(st);
221     }
222     for (int i = 1; i < _field_values.length(); i++) {
223       st->print(", ");
224       _field_values.at(i)->print_on(st);
225     }
226   }
227 #endif
228 }
229 
230 
231 // ObjectMergeValue
232 
233 // Returns the ObjectValue that should be used for the local that this
234 // ObjectMergeValue represents. ObjectMergeValue represents allocation
235 // merges in C2. This method will select which path the allocation merge
236 // took during execution of the Trap that triggered the rematerialization
237 // of the object.
238 ObjectValue* ObjectMergeValue::select(frame& fr, RegisterMap& reg_map) {
239   StackValue* sv_selector = StackValue::create_stack_value(&fr, &reg_map, _selector);
240   jint selector = sv_selector->get_jint();
241 
242   // If the selector is '-1' it means that execution followed the path
243   // where no scalar replacement happened.
244   // Otherwise, it is the index in _possible_objects array that holds
245   // the description of the scalar replaced object.
246   if (selector == -1) {
247     StackValue* sv_merge_pointer = StackValue::create_stack_value(&fr, &reg_map, _merge_pointer);
248     _selected = new ObjectValue(id(), nullptr, false);
249 
250     // Retrieve the pointer to the real object and use it as if we had
251     // allocated it during the deoptimization
252     _selected->set_value(sv_merge_pointer->get_obj()());
253 
254     return _selected;
255   } else {
256     assert(selector < _possible_objects.length(), "sanity");
257     _selected = (ObjectValue*) _possible_objects.at(selector);
258     return _selected;
259   }
260 }
261 
262 Handle ObjectMergeValue::value() const {
263   if (_selected != nullptr) {
264     return _selected->value();
265   } else {
266     return Handle();
267   }
268 }
269 
270 void ObjectMergeValue::read_object(DebugInfoReadStream* stream) {
271   _selector = read_from(stream);
272   _merge_pointer = read_from(stream);
273   int ncandidates = stream->read_int();
274   for (int i = 0; i < ncandidates; i++) {
275     ScopeValue* result = read_from(stream);
276     assert(result->is_object(), "Candidate is not an object!");
277     ObjectValue* obj = result->as_ObjectValue();
278     _possible_objects.append(obj);
279   }
280 }
281 
282 void ObjectMergeValue::write_on(DebugInfoWriteStream* stream) {
283   if (is_visited()) {
284     stream->write_int(OBJECT_ID_CODE);
285     stream->write_int(_id);
286   } else {
287     set_visited(true);
288     stream->write_int(OBJECT_MERGE_CODE);
289     stream->write_int(_id);
290     _selector->write_on(stream);
291     _merge_pointer->write_on(stream);
292     int ncandidates = _possible_objects.length();
293     stream->write_int(ncandidates);
294     for (int i = 0; i < ncandidates; i++) {
295       _possible_objects.at(i)->as_ObjectValue()->write_on(stream);
296     }
297   }
298 }
299 
300 // ConstantIntValue
301 
302 ConstantIntValue::ConstantIntValue(DebugInfoReadStream* stream) {
303   _value = stream->read_signed_int();
304 }
305 
306 void ConstantIntValue::write_on(DebugInfoWriteStream* stream) {
307   stream->write_int(CONSTANT_INT_CODE);
308   stream->write_signed_int(value());
309 }
310 
311 void ConstantIntValue::print_on(outputStream* st) const {
312   st->print("%d", value());
313 }
314 
315 // ConstantLongValue
316 
317 ConstantLongValue::ConstantLongValue(DebugInfoReadStream* stream) {
318   _value = stream->read_long();
319 }
320 
321 void ConstantLongValue::write_on(DebugInfoWriteStream* stream) {
322   stream->write_int(CONSTANT_LONG_CODE);
323   stream->write_long(value());
324 }
325 
326 void ConstantLongValue::print_on(outputStream* st) const {
327   st->print(JLONG_FORMAT, value());
328 }
329 
330 // ConstantDoubleValue
331 
332 ConstantDoubleValue::ConstantDoubleValue(DebugInfoReadStream* stream) {
333   _value = stream->read_double();
334 }
335 
336 void ConstantDoubleValue::write_on(DebugInfoWriteStream* stream) {
337   stream->write_int(CONSTANT_DOUBLE_CODE);
338   stream->write_double(value());
339 }
340 
341 void ConstantDoubleValue::print_on(outputStream* st) const {
342   st->print("%f", value());
343 }
344 
345 // ConstantOopWriteValue
346 
347 void ConstantOopWriteValue::write_on(DebugInfoWriteStream* stream) {
348 #ifdef ASSERT
349   {
350     // cannot use ThreadInVMfromNative here since in case of JVMCI compiler,
351     // thread is already in VM state.
352     ThreadInVMfromUnknown tiv;
353     assert(JNIHandles::resolve(value()) == nullptr ||
354            Universe::heap()->is_in(JNIHandles::resolve(value())),
355            "Should be in heap");
356  }
357 #endif
358   stream->write_int(CONSTANT_OOP_CODE);
359   stream->write_handle(value());
360 }
361 
362 void ConstantOopWriteValue::print_on(outputStream* st) const {
363   // using ThreadInVMfromUnknown here since in case of JVMCI compiler,
364   // thread is already in VM state.
365   ThreadInVMfromUnknown tiv;
366   JNIHandles::resolve(value())->print_value_on(st);
367 }
368 
369 
370 // ConstantOopReadValue
371 
372 ConstantOopReadValue::ConstantOopReadValue(DebugInfoReadStream* stream) {
373   _value = Handle(Thread::current(), stream->read_oop());
374   assert(_value() == nullptr ||
375          Universe::heap()->is_in(_value()), "Should be in heap");
376 }
377 
378 void ConstantOopReadValue::write_on(DebugInfoWriteStream* stream) {
379   ShouldNotReachHere();
380 }
381 
382 void ConstantOopReadValue::print_on(outputStream* st) const {
383   if (value()() != nullptr) {
384     value()()->print_value_on(st);
385   } else {
386     st->print("null");
387   }
388 }
389 
390 
391 // MonitorValue
392 
393 MonitorValue::MonitorValue(ScopeValue* owner, Location basic_lock, bool eliminated) {
394   _owner       = owner;
395   _basic_lock  = basic_lock;
396   _eliminated  = eliminated;
397 }
398 
399 MonitorValue::MonitorValue(DebugInfoReadStream* stream) {
400   _basic_lock  = Location(stream);
401   _owner       = ScopeValue::read_from(stream);
402   _eliminated  = (stream->read_bool() != 0);
403 }
404 
405 void MonitorValue::write_on(DebugInfoWriteStream* stream) {
406   _basic_lock.write_on(stream);
407   _owner->write_on(stream);
408   stream->write_bool(_eliminated);
409 }
410 
411 #ifndef PRODUCT
412 void MonitorValue::print_on(outputStream* st) const {
413   st->print("monitor{");
414   owner()->print_on(st);
415   st->print(",");
416   basic_lock().print_on(st);
417   st->print("}");
418   if (_eliminated) {
419     st->print(" (eliminated)");
420   }
421 }
422 #endif