1 /*
2 * Copyright (c) 2019, 2025, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2019 SAP SE. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "classfile/vmClasses.hpp"
27 #include "classfile/vmSymbols.hpp"
28 #include "gc/shared/gcLocker.hpp"
29 #include "interpreter/bytecodeUtils.hpp"
30 #include "memory/resourceArea.hpp"
31 #include "runtime/signature.hpp"
32 #include "runtime/safepointVerifiers.hpp"
33 #include "utilities/events.hpp"
34 #include "utilities/ostream.hpp"
35
36 class SimulatedOperandStack;
37 class ExceptionMessageBuilder;
38
39 // The entries of a SimulatedOperandStack. They carry the analysis
40 // information gathered for the slot.
41 class StackSlotAnalysisData {
42 private:
43
44 friend class SimulatedOperandStack;
45 friend class ExceptionMessageBuilder;
46
47 unsigned int _bci:17; // The bci of the bytecode that pushed the current value on the operand stack.
48 // INVALID if ambiguous, e.g. after a control flow merge.
49 // 16 bits for bci (max bytecode size) and one for INVALID.
50 unsigned int _type:15; // The BasicType of the value on the operand stack.
51
52 // Merges this slot data with the given one and returns the result. If
53 // the bcis of the two merged objects are different, the bci of the result
54 // will be undefined. If the types are different, the result type is T_CONFLICT.
55 // (An exception is if one type is an array and the other is object, then
56 // the result type will be T_OBJECT).
57 StackSlotAnalysisData merge(StackSlotAnalysisData other);
58
59 public:
60
61 // Creates a new object with an invalid bci and the given type.
62 StackSlotAnalysisData(BasicType type = T_CONFLICT);
63
64 // Creates a new object with the given bci and type.
65 StackSlotAnalysisData(int bci, BasicType type);
66
67 enum {
68 // An invalid bytecode index, as > 65535.
69 INVALID = 0x1FFFF
70 };
71
72 // Returns the bci. If the bci is invalid, INVALID is returned.
73 unsigned int get_bci();
74
75 // Returns true, if the bci is not invalid.
76 bool has_bci() { return get_bci() != INVALID; }
77
78 // Returns the type of the slot data.
79 BasicType get_type();
80 };
81
82 // A stack consisting of SimulatedOperandStackEntries.
83 // This represents the analysis information for the operand stack
84 // for a given bytecode at a given bci.
85 // It also holds an additional field that serves to collect
86 // information whether local slots were written.
87 class SimulatedOperandStack: CHeapObj<mtInternal> {
88
89 private:
90
91 friend class ExceptionMessageBuilder;
92 friend class StackSlotAnalysisData;
93
94 // The stack.
95 GrowableArray<StackSlotAnalysisData> _stack;
96
97 // Optimized bytecode can reuse local variable slots for several
98 // local variables.
99 // If there is no variable name information, we print 'parameter<i>'
100 // if a parameter maps to a local slot. Once a local slot has been
101 // written, we don't know any more whether it was written as the
102 // corresponding parameter, or whether another local has been
103 // mapped to the slot. So we don't want to print 'parameter<i>' any
104 // more, but 'local<i>'. Similarly for 'this'.
105 // Therefore, during the analysis, we mark a bit for local slots that
106 // get written and propagate this information.
107 // We only run the analysis for 64 slots. If a method has more
108 // parameters, we print 'local<i>' in all cases.
109 uint64_t _written_local_slots;
110
111 SimulatedOperandStack(): _written_local_slots(0) { };
112 SimulatedOperandStack(const SimulatedOperandStack ©);
113
114 // Pushes the given slot data.
115 void push_raw(StackSlotAnalysisData slotData);
116
117 // Like push_raw, but if the slotData has type long or double, we push two.
118 void push(StackSlotAnalysisData slotData);
119
120 // Like push(slotData), but using bci/type to create an instance of
121 // StackSlotAnalysisData first.
122 void push(int bci, BasicType type);
123
124 // Pops the given number of entries.
125 void pop(int slots);
126
127 // Merges this with the given stack by merging all entries. The
128 // size of the stacks must be the same.
129 void merge(SimulatedOperandStack const& other);
130
131 public:
132
133 // Returns the size of the stack.
134 int get_size() const;
135
136 // Returns the slot data at the given index. Slot 0 is top of stack.
137 StackSlotAnalysisData get_slot_data(int slot);
138
139 // Mark that local slot i was written.
140 void set_local_slot_written(int i);
141
142 // Check whether local slot i was written by this or a previous bytecode.
143 bool local_slot_was_written(int i);
144 };
145
146 // Helper class to build internal exception messages for exceptions
147 // that are thrown because prerequisites to execute a bytecode
148 // are not met.
149 // E.g., if a NPE is thrown because an iload can not be executed
150 // by the VM because the reference to load from is null.
151 //
152 // It analyses the bytecode to assemble Java-like message text
153 // to give precise information where in a larger expression the
154 // exception occurred.
155 //
156 // To assemble this message text, it is needed to know how
157 // operand stack slot entries were pushed on the operand stack.
158 // This class contains an analysis over the bytecodes to compute
159 // this information. The information is stored in a
160 // SimulatedOperandStack for each bytecode.
161 class ExceptionMessageBuilder : public StackObj {
162
163 // The stacks for each bytecode.
164 GrowableArray<SimulatedOperandStack*>* _stacks;
165
166 // The method.
167 Method* _method;
168
169 // The number of entries used (the sum of all entries of all stacks).
170 int _nr_of_entries;
171
172 // If true, we have added at least one new stack.
173 bool _added_one;
174
175 // If true, we have processed all bytecodes.
176 bool _all_processed;
177
178 // The maximum number of entries we want to use. This is used to
179 // limit the amount of memory we waste for insane methods (as they
180 // appear in JCK tests).
181 static const int _max_entries = 1000000;
182
183 static const int _max_cause_detail = 5;
184
185 // Merges the stack at the given bci with the given stack. If there
186 // is no stack at the bci, we just put the given stack there. This
187 // method doesn't takes ownership of the stack.
188 void merge(int bci, SimulatedOperandStack* stack);
189
190 // Processes the instruction at the given bci in the method. Returns
191 // the size of the instruction.
192 int do_instruction(int bci);
193
194 bool print_NPE_cause0(outputStream *os, int bci, int slot, int max_detail,
195 bool inner_expr = false, const char *prefix = nullptr);
196
197 public:
198
199 // Creates an ExceptionMessageBuilder object and runs the analysis
200 // building SimulatedOperandStacks for each bytecode in the given
201 // method (the method must be rewritten already). Note that you're
202 // not allowed to use this object when crossing a safepoint! If the
203 // bci is != -1, we only create the stacks as far as needed to get a
204 // stack for the bci.
205 ExceptionMessageBuilder(Method* method, int bci = -1);
206
207 // Releases the resources.
208 ~ExceptionMessageBuilder();
209
210 // Returns the number of stacks (this is the size of the method).
211 int get_size() { return _stacks->length() - 1; }
212
213 // Assuming that a NullPointerException was thrown at the given bci,
214 // we return the nr of the slot holding the null reference. If this
215 // NPE is created by hand, we return -2 as the slot. If there
216 // cannot be a NullPointerException at the bci, -1 is returned.
217 int get_NPE_null_slot(int bci);
218
219 // Prints a java-like expression for the bytecode that pushed
220 // the value to the given slot being live at the given bci.
221 // It constructs the expression by recursing backwards over the
222 // bytecode using the results of the analysis done in the
223 // constructor of ExceptionMessageBuilder.
224 // os: The stream to print the message to.
225 // bci: The index of the bytecode that caused the NPE.
226 // slot: The slot on the operand stack that contains null.
227 // The slots are numbered from TOS downwards, i.e.,
228 // TOS has the slot number 0, that below 1 and so on.
229 //
230 // Returns false if nothing was printed, else true.
231 bool print_NPE_cause(outputStream *os, int bci, int slot);
232
233 // Prints a string describing the failed action.
234 void print_NPE_failed_action(outputStream *os, int bci);
235 };
236
237 // Replaces the following well-known class names:
238 // java.lang.Object -> Object
239 // java.lang.String -> String
240 static char *trim_well_known_class_names_from_signature(char *signature) {
241 size_t len = strlen(signature);
242 size_t skip_len = strlen("java.lang.");
243 size_t min_pattern_len = strlen("java.lang.String");
244 if (len < min_pattern_len) return signature;
245
246 for (size_t isrc = 0, idst = 0; isrc <= len; isrc++, idst++) {
247 // We must be careful not to trim names like test.java.lang.String.
248 if ((isrc == 0 && strncmp(signature + isrc, "java.lang.Object", min_pattern_len) == 0) ||
249 (isrc == 0 && strncmp(signature + isrc, "java.lang.String", min_pattern_len) == 0) ||
250 (isrc > 1 && strncmp(signature + isrc-2, ", java.lang.Object", min_pattern_len+2) == 0) ||
251 (isrc > 1 && strncmp(signature + isrc-2, ", java.lang.String", min_pattern_len+2) == 0) ) {
252 isrc += skip_len;
253 }
254 if (idst != isrc) {
255 signature[idst] = signature[isrc];
256 }
257 }
258 return signature;
259 }
260
261 // Replaces the following well-known class names:
262 // java.lang.Object -> Object
263 // java.lang.String -> String
264 static void print_klass_name(outputStream *os, Symbol *klass) {
265 const char *name = klass->as_klass_external_name();
266 if (strcmp(name, "java.lang.Object") == 0) name = "Object";
267 if (strcmp(name, "java.lang.String") == 0) name = "String";
268 os->print("%s", name);
269 }
270
271 // Prints the name of the method that is described at constant pool
272 // index cp_index in the constant pool of method 'method'.
273 static void print_method_name(outputStream *os, Method* method, int cp_index, Bytecodes::Code bc) {
274 ResourceMark rm;
275 ConstantPool* cp = method->constants();
276 Symbol* klass = cp->klass_ref_at_noresolve(cp_index, bc);
277 Symbol* name = cp->name_ref_at(cp_index, bc);
278 Symbol* signature = cp->signature_ref_at(cp_index, bc);
279
280 print_klass_name(os, klass);
281 os->print(".%s(", name->as_C_string());
282 stringStream sig;
283 signature->print_as_signature_external_parameters(&sig);
284 os->print("%s)", trim_well_known_class_names_from_signature(sig.as_string()));
285 }
286
287 // Prints the name of the field that is described at constant pool
288 // index cp_index in the constant pool of method 'method'.
289 static void print_field_and_class(outputStream *os, Method* method, int cp_index, Bytecodes::Code bc) {
290 ResourceMark rm;
291 ConstantPool* cp = method->constants();
292 Symbol* klass = cp->klass_ref_at_noresolve(cp_index, bc);
293 Symbol *name = cp->name_ref_at(cp_index, bc);
294 print_klass_name(os, klass);
295 os->print(".%s", name->as_C_string());
296 }
297
298 // Returns the name of the field that is described at constant pool
299 // index cp_index in the constant pool of method 'method'.
300 static char const* get_field_name(Method* method, int cp_index, Bytecodes::Code bc) {
301 Symbol* name = method->constants()->name_ref_at(cp_index, bc);
302 return name->as_C_string();
303 }
304
305 static void print_local_var(outputStream *os, unsigned int bci, Method* method, int slot, bool is_parameter) {
306 if (method->has_localvariable_table()) {
307 for (int i = 0; i < method->localvariable_table_length(); i++) {
308 LocalVariableTableElement* elem = method->localvariable_table_start() + i;
309 unsigned int start = elem->start_bci;
310 unsigned int end = start + elem->length;
311
312 if ((bci >= start) && (bci < end) && (elem->slot == slot)) {
313 ConstantPool* cp = method->constants();
314 char *var = cp->symbol_at(elem->name_cp_index)->as_C_string();
315 os->print("%s", var);
316
317 return;
318 }
319 }
320 }
321
322 // Handle at least some cases we know.
323 if (!method->is_static() && (slot == 0) && is_parameter) {
324 os->print("this");
325 } else {
326 int curr = method->is_static() ? 0 : 1;
327 SignatureStream ss(method->signature());
328 int param_index = 1;
329 bool found = false;
330
331 for (SignatureStream ss(method->signature()); !ss.is_done(); ss.next()) {
332 if (ss.at_return_type()) {
333 continue;
334 }
335 int size = type2size[ss.type()];
336 if ((slot >= curr) && (slot < curr + size)) {
337 found = true;
338 break;
339 }
340 param_index += 1;
341 curr += size;
342 }
343
344 if (found && is_parameter) {
345 os->print("<parameter%d>", param_index);
346 } else {
347 // This is the best we can do.
348 os->print("<local%d>", slot);
349 }
350 }
351 }
352
353 StackSlotAnalysisData::StackSlotAnalysisData(BasicType type) : _bci(INVALID), _type(type) {}
354
355 StackSlotAnalysisData::StackSlotAnalysisData(int bci, BasicType type) : _bci((u2)bci), _type(type) {
356 assert(bci >= 0, "BCI must be >= 0");
357 assert(bci < 65536, "BCI must be < 65536");
358 }
359
360 unsigned int StackSlotAnalysisData::get_bci() {
361 return _bci;
362 }
363
364 BasicType StackSlotAnalysisData::get_type() {
365 return (BasicType)_type;
366 }
367
368 StackSlotAnalysisData StackSlotAnalysisData::merge(StackSlotAnalysisData other) {
369 if (get_type() != other.get_type()) {
370 if (((get_type() == T_OBJECT) || (get_type() == T_ARRAY)) &&
371 ((other.get_type() == T_OBJECT) || (other.get_type() == T_ARRAY))) {
372 if (get_bci() == other.get_bci()) {
373 return StackSlotAnalysisData(get_bci(), T_OBJECT);
374 } else {
375 return StackSlotAnalysisData(T_OBJECT);
376 }
377 } else {
378 return StackSlotAnalysisData(T_CONFLICT);
379 }
380 }
381
382 if (get_bci() == other.get_bci()) {
383 return *this;
384 } else {
385 return StackSlotAnalysisData(get_type());
386 }
387 }
388
389 SimulatedOperandStack::SimulatedOperandStack(const SimulatedOperandStack ©) {
390 for (int i = 0; i < copy.get_size(); i++) {
391 push_raw(copy._stack.at(i));
392 }
393 _written_local_slots = copy._written_local_slots;
394 }
395
396 void SimulatedOperandStack::push_raw(StackSlotAnalysisData slotData) {
397 if (slotData.get_type() == T_VOID) {
398 return;
399 }
400
401 _stack.push(slotData);
402 }
403
404 void SimulatedOperandStack::push(StackSlotAnalysisData slotData) {
405 if (type2size[slotData.get_type()] == 2) {
406 push_raw(slotData);
407 push_raw(slotData);
408 } else {
409 push_raw(slotData);
410 }
411 }
412
413 void SimulatedOperandStack::push(int bci, BasicType type) {
414 push(StackSlotAnalysisData(bci, type));
415 }
416
417 void SimulatedOperandStack::pop(int slots) {
418 for (int i = 0; i < slots; ++i) {
419 _stack.pop();
420 }
421
422 assert(get_size() >= 0, "Popped too many slots");
423 }
424
425 void SimulatedOperandStack::merge(SimulatedOperandStack const& other) {
426 assert(get_size() == other.get_size(), "Stacks not of same size");
427
428 for (int i = get_size() - 1; i >= 0; --i) {
429 _stack.at_put(i, _stack.at(i).merge(other._stack.at(i)));
430 }
431 _written_local_slots = _written_local_slots | other._written_local_slots;
432 }
433
434 int SimulatedOperandStack::get_size() const {
435 return _stack.length();
436 }
437
438 StackSlotAnalysisData SimulatedOperandStack::get_slot_data(int slot) {
439 assert(slot >= 0, "Slot=%d < 0", slot);
440 assert(slot < get_size(), "Slot=%d >= size=%d", slot, get_size());
441
442 return _stack.at(get_size() - slot - 1);
443 }
444
445 void SimulatedOperandStack::set_local_slot_written(int i) {
446 // Local slots > 63 are very unlikely. Consider these
447 // as written all the time. Saves space and complexity
448 // for dynamic data size.
449 if (i > 63) return;
450 _written_local_slots = _written_local_slots | (1ULL << i);
451 }
452
453 bool SimulatedOperandStack::local_slot_was_written(int i) {
454 if (i > 63) return true;
455 return (_written_local_slots & (1ULL << i)) != 0;
456 }
457
458 ExceptionMessageBuilder::ExceptionMessageBuilder(Method* method, int bci) :
459 _method(method), _nr_of_entries(0),
460 _added_one(true), _all_processed(false) {
461
462 ConstMethod* const_method = method->constMethod();
463 const int len = const_method->code_size();
464
465 assert(bci >= 0, "BCI too low: %d", bci);
466 assert(bci < len, "BCI too large: %d size: %d", bci, len);
467
468 _stacks = new GrowableArray<SimulatedOperandStack*> (len + 1);
469
470 for (int i = 0; i <= len; ++i) {
471 _stacks->push(nullptr);
472 }
473
474 // Initialize stack a bci 0.
475 _stacks->at_put(0, new SimulatedOperandStack());
476
477 // And initialize the start of all exception handlers.
478 if (const_method->has_exception_table()) {
479 ExceptionTableElement *et = const_method->exception_table_start();
480 for (int i = 0; i < const_method->exception_table_length(); ++i) {
481 u2 index = et[i].handler_pc;
482
483 if (_stacks->at(index) == nullptr) {
484 _stacks->at_put(index, new SimulatedOperandStack());
485 _stacks->at(index)->push(index, T_OBJECT);
486 }
487 }
488 }
489
490 // Do this until each bytecode has a stack or we haven't
491 // added a new stack in one iteration.
492 while (!_all_processed && _added_one) {
493 _all_processed = true;
494 _added_one = false;
495
496 for (int i = 0; i < len; ) {
497 // Analyse bytecode i. Step by size of the analyzed bytecode to next bytecode.
498 i += do_instruction(i);
499
500 // If we want the data only for a certain bci, we can possibly end early.
501 if ((bci == i) && (_stacks->at(i) != nullptr)) {
502 _all_processed = true;
503 break;
504 }
505
506 if (_nr_of_entries > _max_entries) {
507 return;
508 }
509 }
510 }
511 }
512
513 ExceptionMessageBuilder::~ExceptionMessageBuilder() {
514 if (_stacks != nullptr) {
515 for (int i = 0; i < _stacks->length(); ++i) {
516 delete _stacks->at(i);
517 }
518 }
519 }
520
521 void ExceptionMessageBuilder::merge(int bci, SimulatedOperandStack* stack) {
522 assert(stack != _stacks->at(bci), "Cannot merge itself");
523
524 if (_stacks->at(bci) != nullptr) {
525 stack->merge(*_stacks->at(bci));
526 } else {
527 // Got a new stack, so count the entries.
528 _nr_of_entries += stack->get_size();
529 }
530
531 // Replace the stack at this bci with a copy of our new merged stack.
532 delete _stacks->at(bci);
533 _stacks->at_put(bci, new SimulatedOperandStack(*stack));
534 }
535
536 int ExceptionMessageBuilder::do_instruction(int bci) {
537 ConstMethod* const_method = _method->constMethod();
538 address code_base = _method->constMethod()->code_base();
539
540 // We use the java code, since we don't want to cope with all the fast variants.
541 int len = Bytecodes::java_length_at(_method, code_base + bci);
542
543 // If we have no stack for this bci, we cannot process the bytecode now.
544 if (_stacks->at(bci) == nullptr) {
545 _all_processed = false;
546 return len;
547 }
548
549 // Make a local copy of the stack for this bci to work on.
550 SimulatedOperandStack* stack = new SimulatedOperandStack(*_stacks->at(bci));
551
552 // dest_bci is != -1 if we branch.
553 int dest_bci = -1;
554
555 // This is for table and lookup switch.
556 static const int initial_length = 2;
557 GrowableArray<int> dests(initial_length);
558
559 bool flow_ended = false;
560
561 // Get the bytecode.
562 bool is_wide = false;
563 Bytecodes::Code raw_code = Bytecodes::code_at(_method, code_base + bci);
564 Bytecodes::Code code = Bytecodes::java_code_at(_method, code_base + bci);
565 int pos = bci + 1;
566
567 if (code == Bytecodes::_wide) {
568 is_wide = true;
569 code = Bytecodes::java_code_at(_method, code_base + bci + 1);
570 pos += 1;
571 }
572
573 // Now simulate the action of each bytecode.
574 switch (code) {
575 case Bytecodes::_nop:
576 case Bytecodes::_aconst_null:
577 case Bytecodes::_iconst_m1:
578 case Bytecodes::_iconst_0:
579 case Bytecodes::_iconst_1:
580 case Bytecodes::_iconst_2:
581 case Bytecodes::_iconst_3:
582 case Bytecodes::_iconst_4:
583 case Bytecodes::_iconst_5:
584 case Bytecodes::_lconst_0:
585 case Bytecodes::_lconst_1:
586 case Bytecodes::_fconst_0:
587 case Bytecodes::_fconst_1:
588 case Bytecodes::_fconst_2:
589 case Bytecodes::_dconst_0:
590 case Bytecodes::_dconst_1:
591 case Bytecodes::_bipush:
592 case Bytecodes::_sipush:
593 case Bytecodes::_iload:
594 case Bytecodes::_lload:
595 case Bytecodes::_fload:
596 case Bytecodes::_dload:
597 case Bytecodes::_aload:
598 case Bytecodes::_iload_0:
599 case Bytecodes::_iload_1:
600 case Bytecodes::_iload_2:
601 case Bytecodes::_iload_3:
602 case Bytecodes::_lload_0:
603 case Bytecodes::_lload_1:
604 case Bytecodes::_lload_2:
605 case Bytecodes::_lload_3:
606 case Bytecodes::_fload_0:
607 case Bytecodes::_fload_1:
608 case Bytecodes::_fload_2:
609 case Bytecodes::_fload_3:
610 case Bytecodes::_dload_0:
611 case Bytecodes::_dload_1:
612 case Bytecodes::_dload_2:
613 case Bytecodes::_dload_3:
614 case Bytecodes::_aload_0:
615 case Bytecodes::_aload_1:
616 case Bytecodes::_aload_2:
617 case Bytecodes::_aload_3:
618 case Bytecodes::_iinc:
619 case Bytecodes::_new:
620 stack->push(bci, Bytecodes::result_type(code));
621 break;
622
623 case Bytecodes::_ldc:
624 case Bytecodes::_ldc_w:
625 case Bytecodes::_ldc2_w: {
626 int cp_index;
627 ConstantPool* cp = _method->constants();
628
629 if (code == Bytecodes::_ldc) {
630 cp_index = *(uint8_t*) (code_base + pos);
631
632 if (raw_code == Bytecodes::_fast_aldc) {
633 cp_index = cp->object_to_cp_index(cp_index);
634 }
635 } else {
636 if (raw_code == Bytecodes::_fast_aldc_w) {
637 cp_index = Bytes::get_native_u2(code_base + pos);
638 cp_index = cp->object_to_cp_index(cp_index);
639 }
640 else {
641 cp_index = Bytes::get_Java_u2(code_base + pos);
642 }
643 }
644
645 constantTag tag = cp->constant_tag_at(cp_index);
646 if (tag.is_klass() || tag.is_unresolved_klass() ||
647 tag.is_method() || tag.is_interface_method() ||
648 tag.is_field() || tag.is_string()) {
649 stack->push(bci, T_OBJECT);
650 } else if (tag.is_int()) {
651 stack->push(bci, T_INT);
652 } else if (tag.is_long()) {
653 stack->push(bci, T_LONG);
654 } else if (tag.is_float()) {
655 stack->push(bci, T_FLOAT);
656 } else if (tag.is_double()) {
657 stack->push(bci, T_DOUBLE);
658 } else {
659 assert(false, "Unexpected tag");
660 }
661 break;
662 }
663
664 case Bytecodes::_iaload:
665 case Bytecodes::_faload:
666 case Bytecodes::_aaload:
667 case Bytecodes::_baload:
668 case Bytecodes::_caload:
669 case Bytecodes::_saload:
670 case Bytecodes::_laload:
671 case Bytecodes::_daload:
672 stack->pop(2);
673 stack->push(bci, Bytecodes::result_type(code));
674 break;
675
676 case Bytecodes::_istore:
677 case Bytecodes::_lstore:
678 case Bytecodes::_fstore:
679 case Bytecodes::_dstore:
680 case Bytecodes::_astore:
681 int index;
682 if (is_wide) {
683 index = Bytes::get_Java_u2(code_base + bci + 2);
684 } else {
685 index = *(uint8_t*) (code_base + bci + 1);
686 }
687 stack->set_local_slot_written(index);
688 stack->pop(-Bytecodes::depth(code));
689 break;
690 case Bytecodes::_istore_0:
691 case Bytecodes::_lstore_0:
692 case Bytecodes::_fstore_0:
693 case Bytecodes::_dstore_0:
694 case Bytecodes::_astore_0:
695 stack->set_local_slot_written(0);
696 stack->pop(-Bytecodes::depth(code));
697 break;
698 case Bytecodes::_istore_1:
699 case Bytecodes::_fstore_1:
700 case Bytecodes::_lstore_1:
701 case Bytecodes::_dstore_1:
702 case Bytecodes::_astore_1:
703 stack->set_local_slot_written(1);
704 stack->pop(-Bytecodes::depth(code));
705 break;
706 case Bytecodes::_istore_2:
707 case Bytecodes::_lstore_2:
708 case Bytecodes::_fstore_2:
709 case Bytecodes::_dstore_2:
710 case Bytecodes::_astore_2:
711 stack->set_local_slot_written(2);
712 stack->pop(-Bytecodes::depth(code));
713 break;
714 case Bytecodes::_istore_3:
715 case Bytecodes::_lstore_3:
716 case Bytecodes::_fstore_3:
717 case Bytecodes::_dstore_3:
718 case Bytecodes::_astore_3:
719 stack->set_local_slot_written(3);
720 stack->pop(-Bytecodes::depth(code));
721 break;
722 case Bytecodes::_iastore:
723 case Bytecodes::_lastore:
724 case Bytecodes::_fastore:
725 case Bytecodes::_dastore:
726 case Bytecodes::_aastore:
727 case Bytecodes::_bastore:
728 case Bytecodes::_castore:
729 case Bytecodes::_sastore:
730 case Bytecodes::_pop:
731 case Bytecodes::_pop2:
732 case Bytecodes::_monitorenter:
733 case Bytecodes::_monitorexit:
734 case Bytecodes::_breakpoint:
735 stack->pop(-Bytecodes::depth(code));
736 break;
737
738 case Bytecodes::_dup:
739 stack->push_raw(stack->get_slot_data(0));
740 break;
741
742 case Bytecodes::_dup_x1: {
743 StackSlotAnalysisData top1 = stack->get_slot_data(0);
744 StackSlotAnalysisData top2 = stack->get_slot_data(1);
745 stack->pop(2);
746 stack->push_raw(top1);
747 stack->push_raw(top2);
748 stack->push_raw(top1);
749 break;
750 }
751
752 case Bytecodes::_dup_x2: {
753 StackSlotAnalysisData top1 = stack->get_slot_data(0);
754 StackSlotAnalysisData top2 = stack->get_slot_data(1);
755 StackSlotAnalysisData top3 = stack->get_slot_data(2);
756 stack->pop(3);
757 stack->push_raw(top1);
758 stack->push_raw(top3);
759 stack->push_raw(top2);
760 stack->push_raw(top1);
761 break;
762 }
763
764 case Bytecodes::_dup2:
765 stack->push_raw(stack->get_slot_data(1));
766 // The former '0' entry is now at '1'.
767 stack->push_raw(stack->get_slot_data(1));
768 break;
769
770 case Bytecodes::_dup2_x1: {
771 StackSlotAnalysisData top1 = stack->get_slot_data(0);
772 StackSlotAnalysisData top2 = stack->get_slot_data(1);
773 StackSlotAnalysisData top3 = stack->get_slot_data(2);
774 stack->pop(3);
775 stack->push_raw(top2);
776 stack->push_raw(top1);
777 stack->push_raw(top3);
778 stack->push_raw(top2);
779 stack->push_raw(top1);
780 break;
781 }
782
783 case Bytecodes::_dup2_x2: {
784 StackSlotAnalysisData top1 = stack->get_slot_data(0);
785 StackSlotAnalysisData top2 = stack->get_slot_data(1);
786 StackSlotAnalysisData top3 = stack->get_slot_data(2);
787 StackSlotAnalysisData top4 = stack->get_slot_data(3);
788 stack->pop(4);
789 stack->push_raw(top2);
790 stack->push_raw(top1);
791 stack->push_raw(top4);
792 stack->push_raw(top3);
793 stack->push_raw(top2);
794 stack->push_raw(top1);
795 break;
796 }
797
798 case Bytecodes::_swap: {
799 StackSlotAnalysisData top1 = stack->get_slot_data(0);
800 StackSlotAnalysisData top2 = stack->get_slot_data(1);
801 stack->pop(2);
802 stack->push(top1);
803 stack->push(top2);
804 break;
805 }
806
807 case Bytecodes::_iadd:
808 case Bytecodes::_ladd:
809 case Bytecodes::_fadd:
810 case Bytecodes::_dadd:
811 case Bytecodes::_isub:
812 case Bytecodes::_lsub:
813 case Bytecodes::_fsub:
814 case Bytecodes::_dsub:
815 case Bytecodes::_imul:
816 case Bytecodes::_lmul:
817 case Bytecodes::_fmul:
818 case Bytecodes::_dmul:
819 case Bytecodes::_idiv:
820 case Bytecodes::_ldiv:
821 case Bytecodes::_fdiv:
822 case Bytecodes::_ddiv:
823 case Bytecodes::_irem:
824 case Bytecodes::_lrem:
825 case Bytecodes::_frem:
826 case Bytecodes::_drem:
827 case Bytecodes::_iand:
828 case Bytecodes::_land:
829 case Bytecodes::_ior:
830 case Bytecodes::_lor:
831 case Bytecodes::_ixor:
832 case Bytecodes::_lxor:
833 stack->pop(2 * type2size[Bytecodes::result_type(code)]);
834 stack->push(bci, Bytecodes::result_type(code));
835 break;
836
837 case Bytecodes::_ineg:
838 case Bytecodes::_lneg:
839 case Bytecodes::_fneg:
840 case Bytecodes::_dneg:
841 stack->pop(type2size[Bytecodes::result_type(code)]);
842 stack->push(bci, Bytecodes::result_type(code));
843 break;
844
845 case Bytecodes::_ishl:
846 case Bytecodes::_lshl:
847 case Bytecodes::_ishr:
848 case Bytecodes::_lshr:
849 case Bytecodes::_iushr:
850 case Bytecodes::_lushr:
851 stack->pop(1 + type2size[Bytecodes::result_type(code)]);
852 stack->push(bci, Bytecodes::result_type(code));
853 break;
854
855 case Bytecodes::_i2l:
856 case Bytecodes::_i2f:
857 case Bytecodes::_i2d:
858 case Bytecodes::_f2i:
859 case Bytecodes::_f2l:
860 case Bytecodes::_f2d:
861 case Bytecodes::_i2b:
862 case Bytecodes::_i2c:
863 case Bytecodes::_i2s:
864 stack->pop(1);
865 stack->push(bci, Bytecodes::result_type(code));
866 break;
867
868 case Bytecodes::_l2i:
869 case Bytecodes::_l2f:
870 case Bytecodes::_l2d:
871 case Bytecodes::_d2i:
872 case Bytecodes::_d2l:
873 case Bytecodes::_d2f:
874 stack->pop(2);
875 stack->push(bci, Bytecodes::result_type(code));
876 break;
877
878 case Bytecodes::_lcmp:
879 case Bytecodes::_fcmpl:
880 case Bytecodes::_fcmpg:
881 case Bytecodes::_dcmpl:
882 case Bytecodes::_dcmpg:
883 stack->pop(1 - Bytecodes::depth(code));
884 stack->push(bci, T_INT);
885 break;
886
887 case Bytecodes::_ifeq:
888 case Bytecodes::_ifne:
889 case Bytecodes::_iflt:
890 case Bytecodes::_ifge:
891 case Bytecodes::_ifgt:
892 case Bytecodes::_ifle:
893 case Bytecodes::_if_icmpeq:
894 case Bytecodes::_if_icmpne:
895 case Bytecodes::_if_icmplt:
896 case Bytecodes::_if_icmpge:
897 case Bytecodes::_if_icmpgt:
898 case Bytecodes::_if_icmple:
899 case Bytecodes::_if_acmpeq:
900 case Bytecodes::_if_acmpne:
901 case Bytecodes::_ifnull:
902 case Bytecodes::_ifnonnull:
903 stack->pop(-Bytecodes::depth(code));
904 dest_bci = bci + (int16_t) Bytes::get_Java_u2(code_base + pos);
905 break;
906
907 case Bytecodes::_jsr:
908 // NOTE: Bytecodes has wrong depth for jsr.
909 stack->push(bci, T_ADDRESS);
910 dest_bci = bci + (int16_t) Bytes::get_Java_u2(code_base + pos);
911 flow_ended = true;
912 break;
913
914 case Bytecodes::_jsr_w: {
915 // NOTE: Bytecodes has wrong depth for jsr.
916 stack->push(bci, T_ADDRESS);
917 dest_bci = bci + (int32_t) Bytes::get_Java_u4(code_base + pos);
918 flow_ended = true;
919 break;
920 }
921
922 case Bytecodes::_ret:
923 // We don't track local variables, so we cannot know were we
924 // return. This makes the stacks imprecise, but we have to
925 // live with that.
926 flow_ended = true;
927 break;
928
929 case Bytecodes::_tableswitch: {
930 stack->pop(1);
931 pos = (pos + 3) & ~3;
932 dest_bci = bci + (int32_t) Bytes::get_Java_u4(code_base + pos);
933 int low = (int32_t) Bytes::get_Java_u4(code_base + pos + 4);
934 int high = (int32_t) Bytes::get_Java_u4(code_base + pos + 8);
935
936 for (int64_t i = low; i <= high; ++i) {
937 dests.push(bci + (int32_t) Bytes::get_Java_u4(code_base + pos + 12 + 4 * (i - low)));
938 }
939
940 break;
941 }
942
943 case Bytecodes::_lookupswitch: {
944 stack->pop(1);
945 pos = (pos + 3) & ~3;
946 dest_bci = bci + (int32_t) Bytes::get_Java_u4(code_base + pos);
947 int nr_of_dests = (int32_t) Bytes::get_Java_u4(code_base + pos + 4);
948
949 for (int i = 0; i < nr_of_dests; ++i) {
950 dests.push(bci + (int32_t) Bytes::get_Java_u4(code_base + pos + 12 + 8 * i));
951 }
952
953 break;
954 }
955
956 case Bytecodes::_ireturn:
957 case Bytecodes::_lreturn:
958 case Bytecodes::_freturn:
959 case Bytecodes::_dreturn:
960 case Bytecodes::_areturn:
961 case Bytecodes::_return:
962 case Bytecodes::_athrow:
963 stack->pop(-Bytecodes::depth(code));
964 flow_ended = true;
965 break;
966
967 case Bytecodes::_getstatic:
968 case Bytecodes::_getfield: {
969 // Find out the type of the field accessed.
970 int cp_index = Bytes::get_native_u2(code_base + pos);
971 ConstantPool* cp = _method->constants();
972 int name_and_type_index = cp->name_and_type_ref_index_at(cp_index, code);
973 int type_index = cp->signature_ref_index_at(name_and_type_index);
974 Symbol* signature = cp->symbol_at(type_index);
975 // Simulate the bytecode: pop the address, push the 'value' loaded
976 // from the field.
977 stack->pop(1 - Bytecodes::depth(code));
978 stack->push(bci, Signature::basic_type(signature));
979 break;
980 }
981
982 case Bytecodes::_putstatic:
983 case Bytecodes::_putfield: {
984 int cp_index = Bytes::get_native_u2(code_base + pos);
985 ConstantPool* cp = _method->constants();
986 int name_and_type_index = cp->name_and_type_ref_index_at(cp_index, code);
987 int type_index = cp->signature_ref_index_at(name_and_type_index);
988 Symbol* signature = cp->symbol_at(type_index);
989 BasicType bt = Signature::basic_type(signature);
990 stack->pop(type2size[bt] - Bytecodes::depth(code) - 1);
991 break;
992 }
993
994 case Bytecodes::_invokevirtual:
995 case Bytecodes::_invokespecial:
996 case Bytecodes::_invokestatic:
997 case Bytecodes::_invokeinterface:
998 case Bytecodes::_invokedynamic: {
999 ConstantPool* cp = _method->constants();
1000 int cp_index;
1001
1002 if (code == Bytecodes::_invokedynamic) {
1003 cp_index = ((int) Bytes::get_native_u4(code_base + pos));
1004 } else {
1005 cp_index = Bytes::get_native_u2(code_base + pos);
1006 }
1007
1008 int name_and_type_index = cp->name_and_type_ref_index_at(cp_index, code);
1009 int type_index = cp->signature_ref_index_at(name_and_type_index);
1010 Symbol* signature = cp->symbol_at(type_index);
1011
1012 if ((code != Bytecodes::_invokestatic) && (code != Bytecodes::_invokedynamic)) {
1013 // Pop receiver.
1014 stack->pop(1);
1015 }
1016
1017 stack->pop(ArgumentSizeComputer(signature).size());
1018 ResultTypeFinder result_type(signature);
1019 stack->push(bci, result_type.type());
1020 break;
1021 }
1022
1023 case Bytecodes::_newarray:
1024 case Bytecodes::_anewarray:
1025 case Bytecodes::_instanceof:
1026 stack->pop(1);
1027 stack->push(bci, Bytecodes::result_type(code));
1028 break;
1029
1030 case Bytecodes::_arraylength:
1031 stack->pop(1);
1032 stack->push(bci, T_INT);
1033 break;
1034
1035 case Bytecodes::_checkcast:
1036 break;
1037
1038 case Bytecodes::_multianewarray:
1039 stack->pop(*(uint8_t*) (code_base + pos + 2));
1040 stack->push(bci, T_OBJECT);
1041 break;
1042
1043 case Bytecodes::_goto:
1044 stack->pop(-Bytecodes::depth(code));
1045 dest_bci = bci + (int16_t) Bytes::get_Java_u2(code_base + pos);
1046 flow_ended = true;
1047 break;
1048
1049
1050 case Bytecodes::_goto_w:
1051 stack->pop(-Bytecodes::depth(code));
1052 dest_bci = bci + (int32_t) Bytes::get_Java_u4(code_base + pos);
1053 flow_ended = true;
1054 break;
1055
1056 default:
1057 // Allow at least the bcis which have stack info to work.
1058 _all_processed = false;
1059 _added_one = false;
1060 delete stack;
1061
1062 return len;
1063 }
1064
1065 // Put new stack to the next instruction, if we might reach it from
1066 // this bci.
1067 if (!flow_ended) {
1068 if (_stacks->at(bci + len) == nullptr) {
1069 _added_one = true;
1070 }
1071 merge(bci + len, stack);
1072 }
1073
1074 // Put the stack to the branch target too.
1075 if (dest_bci != -1) {
1076 if (_stacks->at(dest_bci) == nullptr) {
1077 _added_one = true;
1078 }
1079 merge(dest_bci, stack);
1080 }
1081
1082 // If we have more than one branch target, process these too.
1083 for (int i = 0; i < dests.length(); ++i) {
1084 if (_stacks->at(dests.at(i)) == nullptr) {
1085 _added_one = true;
1086 }
1087 merge(dests.at(i), stack);
1088 }
1089
1090 delete stack;
1091
1092 return len;
1093 }
1094
1095 #define INVALID_BYTECODE_ENCOUNTERED -1
1096 #define NPE_EXPLICIT_CONSTRUCTED -2
1097 int ExceptionMessageBuilder::get_NPE_null_slot(int bci) {
1098 // Get the bytecode.
1099 address code_base = _method->constMethod()->code_base();
1100 Bytecodes::Code code = Bytecodes::java_code_at(_method, code_base + bci);
1101 int pos = bci + 1; // Position of argument of the bytecode.
1102 if (code == Bytecodes::_wide) {
1103 code = Bytecodes::java_code_at(_method, code_base + bci + 1);
1104 pos += 1;
1105 }
1106
1107 switch (code) {
1108 case Bytecodes::_getfield:
1109 case Bytecodes::_arraylength:
1110 case Bytecodes::_athrow:
1111 case Bytecodes::_monitorenter:
1112 case Bytecodes::_monitorexit:
1113 return 0;
1114 case Bytecodes::_iaload:
1115 case Bytecodes::_faload:
1116 case Bytecodes::_aaload:
1117 case Bytecodes::_baload:
1118 case Bytecodes::_caload:
1119 case Bytecodes::_saload:
1120 case Bytecodes::_laload:
1121 case Bytecodes::_daload:
1122 return 1;
1123 case Bytecodes::_iastore:
1124 case Bytecodes::_fastore:
1125 case Bytecodes::_aastore:
1126 case Bytecodes::_bastore:
1127 case Bytecodes::_castore:
1128 case Bytecodes::_sastore:
1129 return 2;
1130 case Bytecodes::_lastore:
1131 case Bytecodes::_dastore:
1132 return 3;
1133 case Bytecodes::_putfield: {
1134 int cp_index = Bytes::get_native_u2(code_base + pos);
1135 ConstantPool* cp = _method->constants();
1136 int name_and_type_index = cp->name_and_type_ref_index_at(cp_index, code);
1137 int type_index = cp->signature_ref_index_at(name_and_type_index);
1138 Symbol* signature = cp->symbol_at(type_index);
1139 BasicType bt = Signature::basic_type(signature);
1140 return type2size[bt];
1141 }
1142 case Bytecodes::_invokevirtual:
1143 case Bytecodes::_invokespecial:
1144 case Bytecodes::_invokeinterface: {
1145 int cp_index = Bytes::get_native_u2(code_base+ pos);
1146 ConstantPool* cp = _method->constants();
1147 int name_and_type_index = cp->name_and_type_ref_index_at(cp_index, code);
1148 int name_index = cp->name_ref_index_at(name_and_type_index);
1149 Symbol* name = cp->symbol_at(name_index);
1150
1151 // Assume the call of a constructor can never cause a NullPointerException
1152 // (which is true in Java). This is mainly used to avoid generating wrong
1153 // messages for NullPointerExceptions created explicitly by new in Java code.
1154 if (name != vmSymbols::object_initializer_name()) {
1155 int type_index = cp->signature_ref_index_at(name_and_type_index);
1156 Symbol* signature = cp->symbol_at(type_index);
1157 // The 'this' parameter was null. Return the slot of it.
1158 return ArgumentSizeComputer(signature).size();
1159 } else {
1160 return NPE_EXPLICIT_CONSTRUCTED;
1161 }
1162 }
1163
1164 default:
1165 break;
1166 }
1167
1168 return INVALID_BYTECODE_ENCOUNTERED;
1169 }
1170
1171 bool ExceptionMessageBuilder::print_NPE_cause(outputStream* os, int bci, int slot) {
1172 if (print_NPE_cause0(os, bci, slot, _max_cause_detail, false, " because \"")) {
1173 os->print("\" is null");
1174 return true;
1175 }
1176 return false;
1177 }
1178
1179 // Recursively print what was null.
1180 //
1181 // Go to the bytecode that pushed slot 'slot' on the operand stack
1182 // at bytecode 'bci'. Compute a message for that bytecode. If
1183 // necessary (array, field), recur further.
1184 // At most do max_detail recursions.
1185 // Prefix is used to print a proper beginning of the whole
1186 // sentence.
1187 // inner_expr is used to omit some text, like 'static' in
1188 // inner expressions like array subscripts.
1189 //
1190 // Returns true if something was printed.
1191 //
1192 bool ExceptionMessageBuilder::print_NPE_cause0(outputStream* os, int bci, int slot,
1193 int max_detail,
1194 bool inner_expr, const char *prefix) {
1195 assert(bci >= 0, "BCI too low");
1196 assert(bci < get_size(), "BCI too large");
1197
1198 if (max_detail <= 0) {
1199 return false;
1200 }
1201
1202 if (_stacks->at(bci) == nullptr) {
1203 return false;
1204 }
1205
1206 SimulatedOperandStack* stack = _stacks->at(bci);
1207 assert(slot >= 0, "Slot nr. too low");
1208 assert(slot < stack->get_size(), "Slot nr. too large");
1209
1210 StackSlotAnalysisData slotData = stack->get_slot_data(slot);
1211
1212 if (!slotData.has_bci()) {
1213 return false;
1214 }
1215
1216 // Get the bytecode.
1217 unsigned int source_bci = slotData.get_bci();
1218 address code_base = _method->constMethod()->code_base();
1219 Bytecodes::Code code = Bytecodes::java_code_at(_method, code_base + source_bci);
1220 bool is_wide = false;
1221 int pos = source_bci + 1;
1222
1223 if (code == Bytecodes::_wide) {
1224 is_wide = true;
1225 code = Bytecodes::java_code_at(_method, code_base + source_bci + 1);
1226 pos += 1;
1227 }
1228
1229 if (max_detail == _max_cause_detail &&
1230 prefix != nullptr &&
1231 code != Bytecodes::_invokevirtual &&
1232 code != Bytecodes::_invokespecial &&
1233 code != Bytecodes::_invokestatic &&
1234 code != Bytecodes::_invokeinterface) {
1235 os->print("%s", prefix);
1236 }
1237
1238 switch (code) {
1239 case Bytecodes::_iload_0:
1240 case Bytecodes::_aload_0:
1241 print_local_var(os, source_bci, _method, 0, !stack->local_slot_was_written(0));
1242 return true;
1243
1244 case Bytecodes::_iload_1:
1245 case Bytecodes::_aload_1:
1246 print_local_var(os, source_bci, _method, 1, !stack->local_slot_was_written(1));
1247 return true;
1248
1249 case Bytecodes::_iload_2:
1250 case Bytecodes::_aload_2:
1251 print_local_var(os, source_bci, _method, 2, !stack->local_slot_was_written(2));
1252 return true;
1253
1254 case Bytecodes::_iload_3:
1255 case Bytecodes::_aload_3:
1256 print_local_var(os, source_bci, _method, 3, !stack->local_slot_was_written(3));
1257 return true;
1258
1259 case Bytecodes::_iload:
1260 case Bytecodes::_aload: {
1261 int index;
1262 if (is_wide) {
1263 index = Bytes::get_Java_u2(code_base + source_bci + 2);
1264 } else {
1265 index = *(uint8_t*) (code_base + source_bci + 1);
1266 }
1267 print_local_var(os, source_bci, _method, index, !stack->local_slot_was_written(index));
1268 return true;
1269 }
1270
1271 case Bytecodes::_aconst_null:
1272 os->print("null");
1273 return true;
1274 case Bytecodes::_iconst_m1:
1275 os->print("-1");
1276 return true;
1277 case Bytecodes::_iconst_0:
1278 os->print("0");
1279 return true;
1280 case Bytecodes::_iconst_1:
1281 os->print("1");
1282 return true;
1283 case Bytecodes::_iconst_2:
1284 os->print("2");
1285 return true;
1286 case Bytecodes::_iconst_3:
1287 os->print("3");
1288 return true;
1289 case Bytecodes::_iconst_4:
1290 os->print("4");
1291 return true;
1292 case Bytecodes::_iconst_5:
1293 os->print("5");
1294 return true;
1295 case Bytecodes::_bipush: {
1296 jbyte con = *(jbyte*) (code_base + source_bci + 1);
1297 os->print("%d", con);
1298 return true;
1299 }
1300 case Bytecodes::_sipush: {
1301 u2 con = Bytes::get_Java_u2(code_base + source_bci + 1);
1302 os->print("%d", con);
1303 return true;
1304 }
1305 case Bytecodes::_iaload:
1306 case Bytecodes::_aaload: {
1307 // Print the 'name' of the array. Go back to the bytecode that
1308 // pushed the array reference on the operand stack.
1309 if (!print_NPE_cause0(os, source_bci, 1, max_detail - 1, inner_expr)) {
1310 // Returned false. Max recursion depth was reached. Print dummy.
1311 os->print("<array>");
1312 }
1313 os->print("[");
1314 // Print the index expression. Go back to the bytecode that
1315 // pushed the index on the operand stack.
1316 // inner_expr == true so we don't print unwanted strings
1317 // as "The return value of'". And don't decrement max_detail so we always
1318 // get a value here and only cancel out on the dereference.
1319 if (!print_NPE_cause0(os, source_bci, 0, max_detail, true)) {
1320 // Returned false. We don't print complex array index expressions. Print placeholder.
1321 os->print("...");
1322 }
1323 os->print("]");
1324 return true;
1325 }
1326
1327 case Bytecodes::_getstatic: {
1328 int cp_index = Bytes::get_native_u2(code_base + pos);
1329 print_field_and_class(os, _method, cp_index, code);
1330 return true;
1331 }
1332
1333 case Bytecodes::_getfield: {
1334 // Print the sender. Go back to the bytecode that
1335 // pushed the sender on the operand stack.
1336 if (print_NPE_cause0(os, source_bci, 0, max_detail - 1, inner_expr)) {
1337 os->print(".");
1338 }
1339 int cp_index = Bytes::get_native_u2(code_base + pos);
1340 os->print("%s", get_field_name(_method, cp_index, code));
1341 return true;
1342 }
1343
1344 case Bytecodes::_invokevirtual:
1345 case Bytecodes::_invokespecial:
1346 case Bytecodes::_invokestatic:
1347 case Bytecodes::_invokeinterface: {
1348 int cp_index = Bytes::get_native_u2(code_base + pos);
1349 if (max_detail == _max_cause_detail && !inner_expr) {
1350 os->print(" because the return value of \"");
1351 }
1352 print_method_name(os, _method, cp_index, code);
1353 return true;
1354 }
1355
1356 default: break;
1357 }
1358 return false;
1359 }
1360
1361 void ExceptionMessageBuilder::print_NPE_failed_action(outputStream *os, int bci) {
1362
1363 // Get the bytecode.
1364 address code_base = _method->constMethod()->code_base();
1365 Bytecodes::Code code = Bytecodes::java_code_at(_method, code_base + bci);
1366 int pos = bci + 1;
1367 if (code == Bytecodes::_wide) {
1368 code = Bytecodes::java_code_at(_method, code_base + bci + 1);
1369 pos += 1;
1370 }
1371
1372 switch (code) {
1373 case Bytecodes::_iaload:
1374 os->print("Cannot load from int array"); break;
1375 case Bytecodes::_faload:
1376 os->print("Cannot load from float array"); break;
1377 case Bytecodes::_aaload:
1378 os->print("Cannot load from object array"); break;
1379 case Bytecodes::_baload:
1380 os->print("Cannot load from byte/boolean array"); break;
1381 case Bytecodes::_caload:
1382 os->print("Cannot load from char array"); break;
1383 case Bytecodes::_saload:
1384 os->print("Cannot load from short array"); break;
1385 case Bytecodes::_laload:
1386 os->print("Cannot load from long array"); break;
1387 case Bytecodes::_daload:
1388 os->print("Cannot load from double array"); break;
1389
1390 case Bytecodes::_iastore:
1391 os->print("Cannot store to int array"); break;
1392 case Bytecodes::_fastore:
1393 os->print("Cannot store to float array"); break;
1394 case Bytecodes::_aastore:
1395 os->print("Cannot store to object array"); break;
1396 case Bytecodes::_bastore:
1397 os->print("Cannot store to byte/boolean array"); break;
1398 case Bytecodes::_castore:
1399 os->print("Cannot store to char array"); break;
1400 case Bytecodes::_sastore:
1401 os->print("Cannot store to short array"); break;
1402 case Bytecodes::_lastore:
1403 os->print("Cannot store to long array"); break;
1404 case Bytecodes::_dastore:
1405 os->print("Cannot store to double array"); break;
1406
1407 case Bytecodes::_arraylength:
1408 os->print("Cannot read the array length"); break;
1409 case Bytecodes::_athrow:
1410 os->print("Cannot throw exception"); break;
1411 case Bytecodes::_monitorenter:
1412 os->print("Cannot enter synchronized block"); break;
1413 case Bytecodes::_monitorexit:
1414 os->print("Cannot exit synchronized block"); break;
1415 case Bytecodes::_getfield: {
1416 int cp_index = Bytes::get_native_u2(code_base + pos);
1417 ConstantPool* cp = _method->constants();
1418 int name_and_type_index = cp->name_and_type_ref_index_at(cp_index, code);
1419 int name_index = cp->name_ref_index_at(name_and_type_index);
1420 Symbol* name = cp->symbol_at(name_index);
1421 os->print("Cannot read field \"%s\"", name->as_C_string());
1422 } break;
1423 case Bytecodes::_putfield: {
1424 int cp_index = Bytes::get_native_u2(code_base + pos);
1425 os->print("Cannot assign field \"%s\"", get_field_name(_method, cp_index, code));
1426 } break;
1427 case Bytecodes::_invokevirtual:
1428 case Bytecodes::_invokespecial:
1429 case Bytecodes::_invokeinterface: {
1430 int cp_index = Bytes::get_native_u2(code_base+ pos);
1431 os->print("Cannot invoke \"");
1432 print_method_name(os, _method, cp_index, code);
1433 os->print("\"");
1434 } break;
1435
1436 default:
1437 assert(0, "We should have checked this bytecode in get_NPE_null_slot().");
1438 break;
1439 }
1440 }
1441
1442 // Main API
1443 bool BytecodeUtils::get_NPE_message_at(outputStream* ss, Method* method, int bci) {
1444
1445 NoSafepointVerifier _nsv; // Cannot use this object over a safepoint.
1446
1447 // If this NPE was created via reflection, we have no real NPE.
1448 if (method->method_holder() ==
1449 vmClasses::reflect_DirectConstructorHandleAccessor_NativeAccessor_klass()) {
1450 return false;
1451 }
1452
1453 // Analyse the bytecodes.
1454 ResourceMark rm;
1455 ExceptionMessageBuilder emb(method, bci);
1456
1457 // The slot of the operand stack that contains the null reference.
1458 // Also checks for NPE explicitly constructed and returns NPE_EXPLICIT_CONSTRUCTED.
1459 int slot = emb.get_NPE_null_slot(bci);
1460
1461 // Build the message.
1462 if (slot == NPE_EXPLICIT_CONSTRUCTED) {
1463 // We don't want to print a message.
1464 return false;
1465 } else if (slot == INVALID_BYTECODE_ENCOUNTERED) {
1466 // We encountered a bytecode that does not dereference a reference.
1467 DEBUG_ONLY(ss->print("There cannot be a NullPointerException at bci %d of method %s",
1468 bci, method->external_name()));
1469 NOT_DEBUG(return false);
1470 } else {
1471 // Print string describing which action (bytecode) could not be
1472 // performed because of the null reference.
1473 emb.print_NPE_failed_action(ss, bci);
1474 // Print a description of what is null.
1475 if (!emb.print_NPE_cause(ss, bci, slot)) {
1476 // Nothing was printed. End the sentence without the 'because'
1477 // subordinate sentence.
1478 }
1479 }
1480 return true;
1481 }