1 /*
2 * Copyright (c) 2005, 2025, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2023, Alibaba Group Holding Limited. 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/classLoaderData.inline.hpp"
27 #include "classfile/classLoaderDataGraph.hpp"
28 #include "classfile/javaClasses.inline.hpp"
29 #include "classfile/symbolTable.hpp"
30 #include "classfile/vmClasses.hpp"
31 #include "classfile/vmSymbols.hpp"
32 #include "gc/shared/gcLocker.hpp"
33 #include "gc/shared/gcVMOperations.hpp"
34 #include "gc/shared/workerThread.hpp"
35 #include "jfr/jfrEvents.hpp"
36 #include "jvm.h"
37 #include "memory/allocation.inline.hpp"
38 #include "memory/resourceArea.hpp"
39 #include "memory/universe.hpp"
40 #include "oops/fieldStreams.inline.hpp"
41 #include "oops/klass.inline.hpp"
42 #include "oops/objArrayKlass.hpp"
43 #include "oops/objArrayOop.inline.hpp"
44 #include "oops/oop.inline.hpp"
45 #include "oops/typeArrayOop.inline.hpp"
46 #include "runtime/arguments.hpp"
47 #include "runtime/continuationWrapper.inline.hpp"
48 #include "runtime/frame.inline.hpp"
49 #include "runtime/handles.inline.hpp"
50 #include "runtime/javaCalls.hpp"
51 #include "runtime/javaThread.inline.hpp"
52 #include "runtime/jniHandles.hpp"
53 #include "runtime/os.hpp"
54 #include "runtime/threads.hpp"
55 #include "runtime/threadSMR.hpp"
56 #include "runtime/timerTrace.hpp"
57 #include "runtime/vframe.hpp"
58 #include "runtime/vmOperations.hpp"
59 #include "runtime/vmThread.hpp"
60 #include "services/heapDumper.hpp"
61 #include "services/heapDumperCompression.hpp"
62 #include "services/threadService.hpp"
63 #include "utilities/checkedCast.hpp"
64 #include "utilities/macros.hpp"
65 #include "utilities/ostream.hpp"
66 #ifdef LINUX
67 #include "os_linux.hpp"
68 #endif
69
70 /*
71 * HPROF binary format - description copied from:
72 * src/share/demo/jvmti/hprof/hprof_io.c
73 *
74 *
75 * header "JAVA PROFILE 1.0.2" (0-terminated)
76 *
77 * u4 size of identifiers. Identifiers are used to represent
78 * UTF8 strings, objects, stack traces, etc. They usually
79 * have the same size as host pointers.
80 * u4 high word
81 * u4 low word number of milliseconds since 0:00 GMT, 1/1/70
82 * [record]* a sequence of records.
83 *
84 *
85 * Record format:
86 *
87 * u1 a TAG denoting the type of the record
88 * u4 number of *microseconds* since the time stamp in the
89 * header. (wraps around in a little more than an hour)
90 * u4 number of bytes *remaining* in the record. Note that
91 * this number excludes the tag and the length field itself.
92 * [u1]* BODY of the record (a sequence of bytes)
93 *
94 *
95 * The following TAGs are supported:
96 *
97 * TAG BODY notes
98 *----------------------------------------------------------
99 * HPROF_UTF8 a UTF8-encoded name
100 *
101 * id name ID
102 * [u1]* UTF8 characters (no trailing zero)
103 *
104 * HPROF_LOAD_CLASS a newly loaded class
105 *
106 * u4 class serial number (> 0)
107 * id class object ID
108 * u4 stack trace serial number
109 * id class name ID
110 *
111 * HPROF_UNLOAD_CLASS an unloading class
112 *
113 * u4 class serial_number
114 *
115 * HPROF_FRAME a Java stack frame
116 *
117 * id stack frame ID
118 * id method name ID
119 * id method signature ID
120 * id source file name ID
121 * u4 class serial number
122 * i4 line number. >0: normal
123 * -1: unknown
124 * -2: compiled method
125 * -3: native method
126 *
127 * HPROF_TRACE a Java stack trace
128 *
129 * u4 stack trace serial number
130 * u4 thread serial number
131 * u4 number of frames
132 * [id]* stack frame IDs
133 *
134 *
135 * HPROF_ALLOC_SITES a set of heap allocation sites, obtained after GC
136 *
137 * u2 flags 0x0001: incremental vs. complete
138 * 0x0002: sorted by allocation vs. live
139 * 0x0004: whether to force a GC
140 * u4 cutoff ratio
141 * u4 total live bytes
142 * u4 total live instances
143 * u8 total bytes allocated
144 * u8 total instances allocated
145 * u4 number of sites that follow
146 * [u1 is_array: 0: normal object
147 * 2: object array
148 * 4: boolean array
149 * 5: char array
150 * 6: float array
151 * 7: double array
152 * 8: byte array
153 * 9: short array
154 * 10: int array
155 * 11: long array
156 * u4 class serial number (may be zero during startup)
157 * u4 stack trace serial number
158 * u4 number of bytes alive
159 * u4 number of instances alive
160 * u4 number of bytes allocated
161 * u4]* number of instance allocated
162 *
163 * HPROF_START_THREAD a newly started thread.
164 *
165 * u4 thread serial number (> 0)
166 * id thread object ID
167 * u4 stack trace serial number
168 * id thread name ID
169 * id thread group name ID
170 * id thread group parent name ID
171 *
172 * HPROF_END_THREAD a terminating thread.
173 *
174 * u4 thread serial number
175 *
176 * HPROF_HEAP_SUMMARY heap summary
177 *
178 * u4 total live bytes
179 * u4 total live instances
180 * u8 total bytes allocated
181 * u8 total instances allocated
182 *
183 * HPROF_HEAP_DUMP denote a heap dump
184 *
185 * [heap dump sub-records]*
186 *
187 * There are four kinds of heap dump sub-records:
188 *
189 * u1 sub-record type
190 *
191 * HPROF_GC_ROOT_UNKNOWN unknown root
192 *
193 * id object ID
194 *
195 * HPROF_GC_ROOT_THREAD_OBJ thread object
196 *
197 * id thread object ID (may be 0 for a
198 * thread newly attached through JNI)
199 * u4 thread sequence number
200 * u4 stack trace sequence number
201 *
202 * HPROF_GC_ROOT_JNI_GLOBAL JNI global ref root
203 *
204 * id object ID
205 * id JNI global ref ID
206 *
207 * HPROF_GC_ROOT_JNI_LOCAL JNI local ref
208 *
209 * id object ID
210 * u4 thread serial number
211 * u4 frame # in stack trace (-1 for empty)
212 *
213 * HPROF_GC_ROOT_JAVA_FRAME Java stack frame
214 *
215 * id object ID
216 * u4 thread serial number
217 * u4 frame # in stack trace (-1 for empty)
218 *
219 * HPROF_GC_ROOT_NATIVE_STACK Native stack
220 *
221 * id object ID
222 * u4 thread serial number
223 *
224 * HPROF_GC_ROOT_STICKY_CLASS System class
225 *
226 * id object ID
227 *
228 * HPROF_GC_ROOT_THREAD_BLOCK Reference from thread block
229 *
230 * id object ID
231 * u4 thread serial number
232 *
233 * HPROF_GC_ROOT_MONITOR_USED Busy monitor
234 *
235 * id object ID
236 *
237 * HPROF_GC_CLASS_DUMP dump of a class object
238 *
239 * id class object ID
240 * u4 stack trace serial number
241 * id super class object ID
242 * id class loader object ID
243 * id signers object ID
244 * id protection domain object ID
245 * id reserved
246 * id reserved
247 *
248 * u4 instance size (in bytes)
249 *
250 * u2 size of constant pool
251 * [u2, constant pool index,
252 * ty, type
253 * 2: object
254 * 4: boolean
255 * 5: char
256 * 6: float
257 * 7: double
258 * 8: byte
259 * 9: short
260 * 10: int
261 * 11: long
262 * vl]* and value
263 *
264 * u2 number of static fields
265 * [id, static field name,
266 * ty, type,
267 * vl]* and value
268 *
269 * u2 number of inst. fields (not inc. super)
270 * [id, instance field name,
271 * ty]* type
272 *
273 * HPROF_GC_INSTANCE_DUMP dump of a normal object
274 *
275 * id object ID
276 * u4 stack trace serial number
277 * id class object ID
278 * u4 number of bytes that follow
279 * [vl]* instance field values (class, followed
280 * by super, super's super ...)
281 *
282 * HPROF_GC_OBJ_ARRAY_DUMP dump of an object array
283 *
284 * id array object ID
285 * u4 stack trace serial number
286 * u4 number of elements
287 * id array class ID
288 * [id]* elements
289 *
290 * HPROF_GC_PRIM_ARRAY_DUMP dump of a primitive array
291 *
292 * id array object ID
293 * u4 stack trace serial number
294 * u4 number of elements
295 * u1 element type
296 * 4: boolean array
297 * 5: char array
298 * 6: float array
299 * 7: double array
300 * 8: byte array
301 * 9: short array
302 * 10: int array
303 * 11: long array
304 * [u1]* elements
305 *
306 * HPROF_CPU_SAMPLES a set of sample traces of running threads
307 *
308 * u4 total number of samples
309 * u4 # of traces
310 * [u4 # of samples
311 * u4]* stack trace serial number
312 *
313 * HPROF_CONTROL_SETTINGS the settings of on/off switches
314 *
315 * u4 0x00000001: alloc traces on/off
316 * 0x00000002: cpu sampling on/off
317 * u2 stack trace depth
318 *
319 *
320 * When the header is "JAVA PROFILE 1.0.2" a heap dump can optionally
321 * be generated as a sequence of heap dump segments. This sequence is
322 * terminated by an end record. The additional tags allowed by format
323 * "JAVA PROFILE 1.0.2" are:
324 *
325 * HPROF_HEAP_DUMP_SEGMENT denote a heap dump segment
326 *
327 * [heap dump sub-records]*
328 * The same sub-record types allowed by HPROF_HEAP_DUMP
329 *
330 * HPROF_HEAP_DUMP_END denotes the end of a heap dump
331 *
332 */
333
334
335 // HPROF tags
336
337 enum hprofTag : u1 {
338 // top-level records
339 HPROF_UTF8 = 0x01,
340 HPROF_LOAD_CLASS = 0x02,
341 HPROF_UNLOAD_CLASS = 0x03,
342 HPROF_FRAME = 0x04,
343 HPROF_TRACE = 0x05,
344 HPROF_ALLOC_SITES = 0x06,
345 HPROF_HEAP_SUMMARY = 0x07,
346 HPROF_START_THREAD = 0x0A,
347 HPROF_END_THREAD = 0x0B,
348 HPROF_HEAP_DUMP = 0x0C,
349 HPROF_CPU_SAMPLES = 0x0D,
350 HPROF_CONTROL_SETTINGS = 0x0E,
351
352 // 1.0.2 record types
353 HPROF_HEAP_DUMP_SEGMENT = 0x1C,
354 HPROF_HEAP_DUMP_END = 0x2C,
355
356 // field types
357 HPROF_ARRAY_OBJECT = 0x01,
358 HPROF_NORMAL_OBJECT = 0x02,
359 HPROF_BOOLEAN = 0x04,
360 HPROF_CHAR = 0x05,
361 HPROF_FLOAT = 0x06,
362 HPROF_DOUBLE = 0x07,
363 HPROF_BYTE = 0x08,
364 HPROF_SHORT = 0x09,
365 HPROF_INT = 0x0A,
366 HPROF_LONG = 0x0B,
367
368 // data-dump sub-records
369 HPROF_GC_ROOT_UNKNOWN = 0xFF,
370 HPROF_GC_ROOT_JNI_GLOBAL = 0x01,
371 HPROF_GC_ROOT_JNI_LOCAL = 0x02,
372 HPROF_GC_ROOT_JAVA_FRAME = 0x03,
373 HPROF_GC_ROOT_NATIVE_STACK = 0x04,
374 HPROF_GC_ROOT_STICKY_CLASS = 0x05,
375 HPROF_GC_ROOT_THREAD_BLOCK = 0x06,
376 HPROF_GC_ROOT_MONITOR_USED = 0x07,
377 HPROF_GC_ROOT_THREAD_OBJ = 0x08,
378 HPROF_GC_CLASS_DUMP = 0x20,
379 HPROF_GC_INSTANCE_DUMP = 0x21,
380 HPROF_GC_OBJ_ARRAY_DUMP = 0x22,
381 HPROF_GC_PRIM_ARRAY_DUMP = 0x23
382 };
383
384 // Default stack trace ID (used for dummy HPROF_TRACE record)
385 enum {
386 STACK_TRACE_ID = 1,
387 INITIAL_CLASS_COUNT = 200
388 };
389
390 // Supports I/O operations for a dump
391 // Base class for dump and parallel dump
392 class AbstractDumpWriter : public CHeapObj<mtInternal> {
393 protected:
394 enum {
395 io_buffer_max_size = 1*M,
396 dump_segment_header_size = 9
397 };
398
399 char* _buffer; // internal buffer
400 size_t _size;
401 size_t _pos;
402
403 bool _in_dump_segment; // Are we currently in a dump segment?
404 bool _is_huge_sub_record; // Are we writing a sub-record larger than the buffer size?
405 DEBUG_ONLY(size_t _sub_record_left;) // The bytes not written for the current sub-record.
406 DEBUG_ONLY(bool _sub_record_ended;) // True if we have called the end_sub_record().
407
408 char* buffer() const { return _buffer; }
409 size_t buffer_size() const { return _size; }
410 void set_position(size_t pos) { _pos = pos; }
411
412 // Can be called if we have enough room in the buffer.
413 void write_fast(const void* s, size_t len);
414
415 // Returns true if we have enough room in the buffer for 'len' bytes.
416 bool can_write_fast(size_t len);
417
418 void write_address(address a);
419
420 public:
421 AbstractDumpWriter() :
422 _buffer(nullptr),
423 _size(io_buffer_max_size),
424 _pos(0),
425 _in_dump_segment(false) { }
426
427 // Total number of bytes written to the disk
428 virtual julong bytes_written() const = 0;
429 // Return non-null if error occurred
430 virtual char const* error() const = 0;
431
432 size_t position() const { return _pos; }
433 // writer functions
434 virtual void write_raw(const void* s, size_t len);
435 void write_u1(u1 x);
436 void write_u2(u2 x);
437 void write_u4(u4 x);
438 void write_u8(u8 x);
439 void write_objectID(oop o);
440 void write_rootID(oop* p);
441 void write_symbolID(Symbol* o);
442 void write_classID(Klass* k);
443 void write_id(u4 x);
444
445 // Start a new sub-record. Starts a new heap dump segment if needed.
446 void start_sub_record(u1 tag, u4 len);
447 // Ends the current sub-record.
448 void end_sub_record();
449 // Finishes the current dump segment if not already finished.
450 void finish_dump_segment();
451 // Flush internal buffer to persistent storage
452 virtual void flush() = 0;
453 };
454
455 void AbstractDumpWriter::write_fast(const void* s, size_t len) {
456 assert(!_in_dump_segment || (_sub_record_left >= len), "sub-record too large");
457 assert(buffer_size() - position() >= len, "Must fit");
458 DEBUG_ONLY(_sub_record_left -= len);
459 memcpy(buffer() + position(), s, len);
460 set_position(position() + len);
461 }
462
463 bool AbstractDumpWriter::can_write_fast(size_t len) {
464 return buffer_size() - position() >= len;
465 }
466
467 // write raw bytes
468 void AbstractDumpWriter::write_raw(const void* s, size_t len) {
469 assert(!_in_dump_segment || (_sub_record_left >= len), "sub-record too large");
470 DEBUG_ONLY(_sub_record_left -= len);
471
472 // flush buffer to make room.
473 while (len > buffer_size() - position()) {
474 assert(!_in_dump_segment || _is_huge_sub_record,
475 "Cannot overflow in non-huge sub-record.");
476 size_t to_write = buffer_size() - position();
477 memcpy(buffer() + position(), s, to_write);
478 s = (void*) ((char*) s + to_write);
479 len -= to_write;
480 set_position(position() + to_write);
481 flush();
482 }
483
484 memcpy(buffer() + position(), s, len);
485 set_position(position() + len);
486 }
487
488 // Makes sure we inline the fast write into the write_u* functions. This is a big speedup.
489 #define WRITE_KNOWN_TYPE(p, len) do { if (can_write_fast((len))) write_fast((p), (len)); \
490 else write_raw((p), (len)); } while (0)
491
492 void AbstractDumpWriter::write_u1(u1 x) {
493 WRITE_KNOWN_TYPE(&x, 1);
494 }
495
496 void AbstractDumpWriter::write_u2(u2 x) {
497 u2 v;
498 Bytes::put_Java_u2((address)&v, x);
499 WRITE_KNOWN_TYPE(&v, 2);
500 }
501
502 void AbstractDumpWriter::write_u4(u4 x) {
503 u4 v;
504 Bytes::put_Java_u4((address)&v, x);
505 WRITE_KNOWN_TYPE(&v, 4);
506 }
507
508 void AbstractDumpWriter::write_u8(u8 x) {
509 u8 v;
510 Bytes::put_Java_u8((address)&v, x);
511 WRITE_KNOWN_TYPE(&v, 8);
512 }
513
514 void AbstractDumpWriter::write_address(address a) {
515 #ifdef _LP64
516 write_u8((u8)a);
517 #else
518 write_u4((u4)a);
519 #endif
520 }
521
522 void AbstractDumpWriter::write_objectID(oop o) {
523 write_address(cast_from_oop<address>(o));
524 }
525
526 void AbstractDumpWriter::write_rootID(oop* p) {
527 write_address((address)p);
528 }
529
530 void AbstractDumpWriter::write_symbolID(Symbol* s) {
531 write_address((address)((uintptr_t)s));
532 }
533
534 void AbstractDumpWriter::write_id(u4 x) {
535 #ifdef _LP64
536 write_u8((u8) x);
537 #else
538 write_u4(x);
539 #endif
540 }
541
542 // We use java mirror as the class ID
543 void AbstractDumpWriter::write_classID(Klass* k) {
544 write_objectID(k->java_mirror());
545 }
546
547 void AbstractDumpWriter::finish_dump_segment() {
548 if (_in_dump_segment) {
549 assert(_sub_record_left == 0, "Last sub-record not written completely");
550 assert(_sub_record_ended, "sub-record must have ended");
551
552 // Fix up the dump segment length if we haven't written a huge sub-record last
553 // (in which case the segment length was already set to the correct value initially).
554 if (!_is_huge_sub_record) {
555 assert(position() > dump_segment_header_size, "Dump segment should have some content");
556 Bytes::put_Java_u4((address) (buffer() + 5),
557 (u4) (position() - dump_segment_header_size));
558 } else {
559 // Finish process huge sub record
560 // Set _is_huge_sub_record to false so the parallel dump writer can flush data to file.
561 _is_huge_sub_record = false;
562 }
563
564 _in_dump_segment = false;
565 flush();
566 }
567 }
568
569 void AbstractDumpWriter::start_sub_record(u1 tag, u4 len) {
570 if (!_in_dump_segment) {
571 if (position() > 0) {
572 flush();
573 }
574
575 assert(position() == 0 && buffer_size() > dump_segment_header_size, "Must be at the start");
576
577 write_u1(HPROF_HEAP_DUMP_SEGMENT);
578 write_u4(0); // timestamp
579 // Will be fixed up later if we add more sub-records. If this is a huge sub-record,
580 // this is already the correct length, since we don't add more sub-records.
581 write_u4(len);
582 assert(Bytes::get_Java_u4((address)(buffer() + 5)) == len, "Inconsistent size!");
583 _in_dump_segment = true;
584 _is_huge_sub_record = len > buffer_size() - dump_segment_header_size;
585 } else if (_is_huge_sub_record || (len > buffer_size() - position())) {
586 // This object will not fit in completely or the last sub-record was huge.
587 // Finish the current segment and try again.
588 finish_dump_segment();
589 start_sub_record(tag, len);
590
591 return;
592 }
593
594 DEBUG_ONLY(_sub_record_left = len);
595 DEBUG_ONLY(_sub_record_ended = false);
596
597 write_u1(tag);
598 }
599
600 void AbstractDumpWriter::end_sub_record() {
601 assert(_in_dump_segment, "must be in dump segment");
602 assert(_sub_record_left == 0, "sub-record not written completely");
603 assert(!_sub_record_ended, "Must not have ended yet");
604 DEBUG_ONLY(_sub_record_ended = true);
605 }
606
607 // Supports I/O operations for a dump
608
609 class DumpWriter : public AbstractDumpWriter {
610 private:
611 FileWriter* _writer;
612 AbstractCompressor* _compressor;
613 size_t _bytes_written;
614 char* _error;
615 // Compression support
616 char* _out_buffer;
617 size_t _out_size;
618 size_t _out_pos;
619 char* _tmp_buffer;
620 size_t _tmp_size;
621
622 private:
623 void do_compress();
624
625 public:
626 DumpWriter(const char* path, bool overwrite, AbstractCompressor* compressor);
627 ~DumpWriter();
628 julong bytes_written() const override { return (julong) _bytes_written; }
629 char const* error() const override { return _error; }
630 void set_error(const char* error) { _error = (char*)error; }
631 bool has_error() const { return _error != nullptr; }
632 const char* get_file_path() const { return _writer->get_file_path(); }
633 AbstractCompressor* compressor() { return _compressor; }
634 bool is_overwrite() const { return _writer->is_overwrite(); }
635
636 void flush() override;
637
638 private:
639 // internals for DumpMerger
640 friend class DumpMerger;
641 void set_bytes_written(julong bytes_written) { _bytes_written = bytes_written; }
642 int get_fd() const { return _writer->get_fd(); }
643 void set_compressor(AbstractCompressor* p) { _compressor = p; }
644 };
645
646 DumpWriter::DumpWriter(const char* path, bool overwrite, AbstractCompressor* compressor) :
647 AbstractDumpWriter(),
648 _writer(new (std::nothrow) FileWriter(path, overwrite)),
649 _compressor(compressor),
650 _bytes_written(0),
651 _error(nullptr),
652 _out_buffer(nullptr),
653 _out_size(0),
654 _out_pos(0),
655 _tmp_buffer(nullptr),
656 _tmp_size(0) {
657 _error = (char*)_writer->open_writer();
658 if (_error == nullptr) {
659 _buffer = (char*)os::malloc(io_buffer_max_size, mtInternal);
660 if (compressor != nullptr) {
661 _error = (char*)_compressor->init(io_buffer_max_size, &_out_size, &_tmp_size);
662 if (_error == nullptr) {
663 if (_out_size > 0) {
664 _out_buffer = (char*)os::malloc(_out_size, mtInternal);
665 }
666 if (_tmp_size > 0) {
667 _tmp_buffer = (char*)os::malloc(_tmp_size, mtInternal);
668 }
669 }
670 }
671 }
672 // initialize internal buffer
673 _pos = 0;
674 _size = io_buffer_max_size;
675 }
676
677 DumpWriter::~DumpWriter(){
678 if (_buffer != nullptr) {
679 os::free(_buffer);
680 }
681 if (_out_buffer != nullptr) {
682 os::free(_out_buffer);
683 }
684 if (_tmp_buffer != nullptr) {
685 os::free(_tmp_buffer);
686 }
687 if (_writer != nullptr) {
688 delete _writer;
689 }
690 _bytes_written = -1;
691 }
692
693 // flush any buffered bytes to the file
694 void DumpWriter::flush() {
695 if (_pos <= 0) {
696 return;
697 }
698 if (has_error()) {
699 _pos = 0;
700 return;
701 }
702 char* result = nullptr;
703 if (_compressor == nullptr) {
704 result = (char*)_writer->write_buf(_buffer, _pos);
705 _bytes_written += _pos;
706 } else {
707 do_compress();
708 if (!has_error()) {
709 result = (char*)_writer->write_buf(_out_buffer, _out_pos);
710 _bytes_written += _out_pos;
711 }
712 }
713 _pos = 0; // reset pos to make internal buffer available
714
715 if (result != nullptr) {
716 set_error(result);
717 }
718 }
719
720 void DumpWriter::do_compress() {
721 const char* msg = _compressor->compress(_buffer, _pos, _out_buffer, _out_size,
722 _tmp_buffer, _tmp_size, &_out_pos);
723
724 if (msg != nullptr) {
725 set_error(msg);
726 }
727 }
728
729 class DumperClassCacheTable;
730 class DumperClassCacheTableEntry;
731
732 // Support class with a collection of functions used when dumping the heap
733 class DumperSupport : AllStatic {
734 public:
735
736 // write a header of the given type
737 static void write_header(AbstractDumpWriter* writer, hprofTag tag, u4 len);
738
739 // returns hprof tag for the given type signature
740 static hprofTag sig2tag(Symbol* sig);
741 // returns hprof tag for the given basic type
742 static hprofTag type2tag(BasicType type);
743 // Returns the size of the data to write.
744 static u4 sig2size(Symbol* sig);
745
746 // returns the size of the instance of the given class
747 static u4 instance_size(InstanceKlass* ik, DumperClassCacheTableEntry* class_cache_entry = nullptr);
748
749 // dump a jfloat
750 static void dump_float(AbstractDumpWriter* writer, jfloat f);
751 // dump a jdouble
752 static void dump_double(AbstractDumpWriter* writer, jdouble d);
753 // dumps the raw value of the given field
754 static void dump_field_value(AbstractDumpWriter* writer, char type, oop obj, int offset);
755 // returns the size of the static fields; also counts the static fields
756 static u4 get_static_fields_size(InstanceKlass* ik, u2& field_count);
757 // dumps static fields of the given class
758 static void dump_static_fields(AbstractDumpWriter* writer, Klass* k);
759 // dump the raw values of the instance fields of the given object
760 static void dump_instance_fields(AbstractDumpWriter* writer, oop o, DumperClassCacheTableEntry* class_cache_entry);
761 // get the count of the instance fields for a given class
762 static u2 get_instance_fields_count(InstanceKlass* ik);
763 // dumps the definition of the instance fields for a given class
764 static void dump_instance_field_descriptors(AbstractDumpWriter* writer, Klass* k);
765 // creates HPROF_GC_INSTANCE_DUMP record for the given object
766 static void dump_instance(AbstractDumpWriter* writer, oop o, DumperClassCacheTable* class_cache);
767 // creates HPROF_GC_CLASS_DUMP record for the given instance class
768 static void dump_instance_class(AbstractDumpWriter* writer, InstanceKlass* ik);
769 // creates HPROF_GC_CLASS_DUMP record for a given array class
770 static void dump_array_class(AbstractDumpWriter* writer, Klass* k);
771
772 // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
773 static void dump_object_array(AbstractDumpWriter* writer, objArrayOop array);
774 // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
775 static void dump_prim_array(AbstractDumpWriter* writer, typeArrayOop array);
776 // create HPROF_FRAME record for the given method and bci
777 static void dump_stack_frame(AbstractDumpWriter* writer, int frame_serial_num, int class_serial_num, Method* m, int bci);
778
779 // check if we need to truncate an array
780 static int calculate_array_max_length(AbstractDumpWriter* writer, arrayOop array, short header_size);
781
782 // fixes up the current dump record and writes HPROF_HEAP_DUMP_END record
783 static void end_of_dump(AbstractDumpWriter* writer);
784
785 static oop mask_dormant_archived_object(oop o, oop ref_obj) {
786 if (o != nullptr && o->klass()->java_mirror_no_keepalive() == nullptr) {
787 // Ignore this object since the corresponding java mirror is not loaded.
788 // Might be a dormant archive object.
789 report_dormant_archived_object(o, ref_obj);
790 return nullptr;
791 } else {
792 return o;
793 }
794 }
795
796 static void report_dormant_archived_object(oop o, oop ref_obj) {
797 if (log_is_enabled(Trace, aot, heap)) {
798 ResourceMark rm;
799 if (ref_obj != nullptr) {
800 log_trace(aot, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s) referenced by " INTPTR_FORMAT " (%s)",
801 p2i(o), o->klass()->external_name(),
802 p2i(ref_obj), ref_obj->klass()->external_name());
803 } else {
804 log_trace(aot, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s)",
805 p2i(o), o->klass()->external_name());
806 }
807 }
808 }
809 };
810
811 // Hash table of klasses to the klass metadata. This should greatly improve the
812 // hash dumping performance. This hash table is supposed to be used by a single
813 // thread only.
814 //
815 class DumperClassCacheTableEntry : public CHeapObj<mtServiceability> {
816 friend class DumperClassCacheTable;
817 private:
818 GrowableArray<char> _sigs_start;
819 GrowableArray<int> _offsets;
820 u4 _instance_size;
821 int _entries;
822
823 public:
824 DumperClassCacheTableEntry() : _instance_size(0), _entries(0) {};
825
826 int field_count() { return _entries; }
827 char sig_start(int field_idx) { return _sigs_start.at(field_idx); }
828 int offset(int field_idx) { return _offsets.at(field_idx); }
829 u4 instance_size() { return _instance_size; }
830 };
831
832 class DumperClassCacheTable {
833 private:
834 // HashTable SIZE is specified at compile time so we
835 // use 1031 which is the first prime after 1024.
836 static constexpr size_t TABLE_SIZE = 1031;
837
838 // Maintain the cache for N classes. This limits memory footprint
839 // impact, regardless of how many classes we have in the dump.
840 // This also improves look up performance by keeping the statically
841 // sized table from overloading.
842 static constexpr int CACHE_TOP = 256;
843
844 typedef HashTable<InstanceKlass*, DumperClassCacheTableEntry*,
845 TABLE_SIZE, AnyObj::C_HEAP, mtServiceability> PtrTable;
846 PtrTable* _ptrs;
847
848 // Single-slot cache to handle the major case of objects of the same
849 // class back-to-back, e.g. from T[].
850 InstanceKlass* _last_ik;
851 DumperClassCacheTableEntry* _last_entry;
852
853 void unlink_all(PtrTable* table) {
854 class CleanupEntry: StackObj {
855 public:
856 bool do_entry(InstanceKlass*& key, DumperClassCacheTableEntry*& entry) {
857 delete entry;
858 return true;
859 }
860 } cleanup;
861 table->unlink(&cleanup);
862 }
863
864 public:
865 DumperClassCacheTableEntry* lookup_or_create(InstanceKlass* ik) {
866 if (_last_ik == ik) {
867 return _last_entry;
868 }
869
870 DumperClassCacheTableEntry* entry;
871 DumperClassCacheTableEntry** from_cache = _ptrs->get(ik);
872 if (from_cache == nullptr) {
873 entry = new DumperClassCacheTableEntry();
874 for (HierarchicalFieldStream<JavaFieldStream> fld(ik); !fld.done(); fld.next()) {
875 if (!fld.access_flags().is_static()) {
876 Symbol* sig = fld.signature();
877 entry->_sigs_start.push(sig->char_at(0));
878 entry->_offsets.push(fld.offset());
879 entry->_entries++;
880 entry->_instance_size += DumperSupport::sig2size(sig);
881 }
882 }
883
884 if (_ptrs->number_of_entries() >= CACHE_TOP) {
885 // We do not track the individual hit rates for table entries.
886 // Purge the entire table, and let the cache catch up with new
887 // distribution.
888 unlink_all(_ptrs);
889 }
890
891 _ptrs->put(ik, entry);
892 } else {
893 entry = *from_cache;
894 }
895
896 // Remember for single-slot cache.
897 _last_ik = ik;
898 _last_entry = entry;
899
900 return entry;
901 }
902
903 DumperClassCacheTable() : _ptrs(new (mtServiceability) PtrTable), _last_ik(nullptr), _last_entry(nullptr) {}
904
905 ~DumperClassCacheTable() {
906 unlink_all(_ptrs);
907 delete _ptrs;
908 }
909 };
910
911 // write a header of the given type
912 void DumperSupport:: write_header(AbstractDumpWriter* writer, hprofTag tag, u4 len) {
913 writer->write_u1(tag);
914 writer->write_u4(0); // current ticks
915 writer->write_u4(len);
916 }
917
918 // returns hprof tag for the given type signature
919 hprofTag DumperSupport::sig2tag(Symbol* sig) {
920 switch (sig->char_at(0)) {
921 case JVM_SIGNATURE_CLASS : return HPROF_NORMAL_OBJECT;
922 case JVM_SIGNATURE_ARRAY : return HPROF_NORMAL_OBJECT;
923 case JVM_SIGNATURE_BYTE : return HPROF_BYTE;
924 case JVM_SIGNATURE_CHAR : return HPROF_CHAR;
925 case JVM_SIGNATURE_FLOAT : return HPROF_FLOAT;
926 case JVM_SIGNATURE_DOUBLE : return HPROF_DOUBLE;
927 case JVM_SIGNATURE_INT : return HPROF_INT;
928 case JVM_SIGNATURE_LONG : return HPROF_LONG;
929 case JVM_SIGNATURE_SHORT : return HPROF_SHORT;
930 case JVM_SIGNATURE_BOOLEAN : return HPROF_BOOLEAN;
931 default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
932 }
933 }
934
935 hprofTag DumperSupport::type2tag(BasicType type) {
936 switch (type) {
937 case T_BYTE : return HPROF_BYTE;
938 case T_CHAR : return HPROF_CHAR;
939 case T_FLOAT : return HPROF_FLOAT;
940 case T_DOUBLE : return HPROF_DOUBLE;
941 case T_INT : return HPROF_INT;
942 case T_LONG : return HPROF_LONG;
943 case T_SHORT : return HPROF_SHORT;
944 case T_BOOLEAN : return HPROF_BOOLEAN;
945 default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
946 }
947 }
948
949 u4 DumperSupport::sig2size(Symbol* sig) {
950 switch (sig->char_at(0)) {
951 case JVM_SIGNATURE_CLASS:
952 case JVM_SIGNATURE_ARRAY: return sizeof(address);
953 case JVM_SIGNATURE_BOOLEAN:
954 case JVM_SIGNATURE_BYTE: return 1;
955 case JVM_SIGNATURE_SHORT:
956 case JVM_SIGNATURE_CHAR: return 2;
957 case JVM_SIGNATURE_INT:
958 case JVM_SIGNATURE_FLOAT: return 4;
959 case JVM_SIGNATURE_LONG:
960 case JVM_SIGNATURE_DOUBLE: return 8;
961 default: ShouldNotReachHere(); /* to shut up compiler */ return 0;
962 }
963 }
964
965 template<typename T, typename F> T bit_cast(F from) { // replace with the real thing when we can use c++20
966 T to;
967 static_assert(sizeof(to) == sizeof(from), "must be of the same size");
968 memcpy(&to, &from, sizeof(to));
969 return to;
970 }
971
972 // dump a jfloat
973 void DumperSupport::dump_float(AbstractDumpWriter* writer, jfloat f) {
974 if (g_isnan(f)) {
975 writer->write_u4(0x7fc00000); // collapsing NaNs
976 } else {
977 writer->write_u4(bit_cast<u4>(f));
978 }
979 }
980
981 // dump a jdouble
982 void DumperSupport::dump_double(AbstractDumpWriter* writer, jdouble d) {
983 if (g_isnan(d)) {
984 writer->write_u8(0x7ff80000ull << 32); // collapsing NaNs
985 } else {
986 writer->write_u8(bit_cast<u8>(d));
987 }
988 }
989
990 // dumps the raw value of the given field
991 void DumperSupport::dump_field_value(AbstractDumpWriter* writer, char type, oop obj, int offset) {
992 switch (type) {
993 case JVM_SIGNATURE_CLASS :
994 case JVM_SIGNATURE_ARRAY : {
995 oop o = obj->obj_field_access<ON_UNKNOWN_OOP_REF | AS_NO_KEEPALIVE>(offset);
996 o = mask_dormant_archived_object(o, obj);
997 assert(oopDesc::is_oop_or_null(o), "Expected an oop or nullptr at " PTR_FORMAT, p2i(o));
998 writer->write_objectID(o);
999 break;
1000 }
1001 case JVM_SIGNATURE_BYTE : {
1002 jbyte b = obj->byte_field(offset);
1003 writer->write_u1(b);
1004 break;
1005 }
1006 case JVM_SIGNATURE_CHAR : {
1007 jchar c = obj->char_field(offset);
1008 writer->write_u2(c);
1009 break;
1010 }
1011 case JVM_SIGNATURE_SHORT : {
1012 jshort s = obj->short_field(offset);
1013 writer->write_u2(s);
1014 break;
1015 }
1016 case JVM_SIGNATURE_FLOAT : {
1017 jfloat f = obj->float_field(offset);
1018 dump_float(writer, f);
1019 break;
1020 }
1021 case JVM_SIGNATURE_DOUBLE : {
1022 jdouble d = obj->double_field(offset);
1023 dump_double(writer, d);
1024 break;
1025 }
1026 case JVM_SIGNATURE_INT : {
1027 jint i = obj->int_field(offset);
1028 writer->write_u4(i);
1029 break;
1030 }
1031 case JVM_SIGNATURE_LONG : {
1032 jlong l = obj->long_field(offset);
1033 writer->write_u8(l);
1034 break;
1035 }
1036 case JVM_SIGNATURE_BOOLEAN : {
1037 jboolean b = obj->bool_field(offset);
1038 writer->write_u1(b);
1039 break;
1040 }
1041 default : {
1042 ShouldNotReachHere();
1043 break;
1044 }
1045 }
1046 }
1047
1048 // returns the size of the instance of the given class
1049 u4 DumperSupport::instance_size(InstanceKlass* ik, DumperClassCacheTableEntry* class_cache_entry) {
1050 if (class_cache_entry != nullptr) {
1051 return class_cache_entry->instance_size();
1052 } else {
1053 u4 size = 0;
1054 for (HierarchicalFieldStream<JavaFieldStream> fld(ik); !fld.done(); fld.next()) {
1055 if (!fld.access_flags().is_static()) {
1056 size += sig2size(fld.signature());
1057 }
1058 }
1059 return size;
1060 }
1061 }
1062
1063 u4 DumperSupport::get_static_fields_size(InstanceKlass* ik, u2& field_count) {
1064 field_count = 0;
1065 u4 size = 0;
1066
1067 for (JavaFieldStream fldc(ik); !fldc.done(); fldc.next()) {
1068 if (fldc.access_flags().is_static()) {
1069 field_count++;
1070 size += sig2size(fldc.signature());
1071 }
1072 }
1073
1074 // Add in resolved_references which is referenced by the cpCache
1075 // The resolved_references is an array per InstanceKlass holding the
1076 // strings and other oops resolved from the constant pool.
1077 oop resolved_references = ik->constants()->resolved_references_or_null();
1078 if (resolved_references != nullptr) {
1079 field_count++;
1080 size += sizeof(address);
1081
1082 // Add in the resolved_references of the used previous versions of the class
1083 // in the case of RedefineClasses
1084 InstanceKlass* prev = ik->previous_versions();
1085 while (prev != nullptr && prev->constants()->resolved_references_or_null() != nullptr) {
1086 field_count++;
1087 size += sizeof(address);
1088 prev = prev->previous_versions();
1089 }
1090 }
1091
1092 // Also provide a pointer to the init_lock if present, so there aren't unreferenced int[0]
1093 // arrays.
1094 oop init_lock = ik->init_lock();
1095 if (init_lock != nullptr) {
1096 field_count++;
1097 size += sizeof(address);
1098 }
1099
1100 // We write the value itself plus a name and a one byte type tag per field.
1101 return checked_cast<u4>(size + field_count * (sizeof(address) + 1));
1102 }
1103
1104 // dumps static fields of the given class
1105 void DumperSupport::dump_static_fields(AbstractDumpWriter* writer, Klass* k) {
1106 InstanceKlass* ik = InstanceKlass::cast(k);
1107
1108 // dump the field descriptors and raw values
1109 for (JavaFieldStream fld(ik); !fld.done(); fld.next()) {
1110 if (fld.access_flags().is_static()) {
1111 Symbol* sig = fld.signature();
1112
1113 writer->write_symbolID(fld.name()); // name
1114 writer->write_u1(sig2tag(sig)); // type
1115
1116 // value
1117 dump_field_value(writer, sig->char_at(0), ik->java_mirror(), fld.offset());
1118 }
1119 }
1120
1121 // Add resolved_references for each class that has them
1122 oop resolved_references = ik->constants()->resolved_references_or_null();
1123 if (resolved_references != nullptr) {
1124 writer->write_symbolID(vmSymbols::resolved_references_name()); // name
1125 writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
1126 writer->write_objectID(resolved_references);
1127
1128 // Also write any previous versions
1129 InstanceKlass* prev = ik->previous_versions();
1130 while (prev != nullptr && prev->constants()->resolved_references_or_null() != nullptr) {
1131 writer->write_symbolID(vmSymbols::resolved_references_name()); // name
1132 writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
1133 writer->write_objectID(prev->constants()->resolved_references());
1134 prev = prev->previous_versions();
1135 }
1136 }
1137
1138 // Add init lock to the end if the class is not yet initialized
1139 oop init_lock = ik->init_lock();
1140 if (init_lock != nullptr) {
1141 writer->write_symbolID(vmSymbols::init_lock_name()); // name
1142 writer->write_u1(sig2tag(vmSymbols::int_array_signature())); // type
1143 writer->write_objectID(init_lock);
1144 }
1145 }
1146
1147 // dump the raw values of the instance fields of the given object
1148 void DumperSupport::dump_instance_fields(AbstractDumpWriter* writer, oop o, DumperClassCacheTableEntry* class_cache_entry) {
1149 assert(class_cache_entry != nullptr, "Pre-condition: must be provided");
1150 for (int idx = 0; idx < class_cache_entry->field_count(); idx++) {
1151 dump_field_value(writer, class_cache_entry->sig_start(idx), o, class_cache_entry->offset(idx));
1152 }
1153 }
1154
1155 // dumps the definition of the instance fields for a given class
1156 u2 DumperSupport::get_instance_fields_count(InstanceKlass* ik) {
1157 u2 field_count = 0;
1158
1159 for (JavaFieldStream fldc(ik); !fldc.done(); fldc.next()) {
1160 if (!fldc.access_flags().is_static()) field_count++;
1161 }
1162
1163 return field_count;
1164 }
1165
1166 // dumps the definition of the instance fields for a given class
1167 void DumperSupport::dump_instance_field_descriptors(AbstractDumpWriter* writer, Klass* k) {
1168 InstanceKlass* ik = InstanceKlass::cast(k);
1169
1170 // dump the field descriptors
1171 for (JavaFieldStream fld(ik); !fld.done(); fld.next()) {
1172 if (!fld.access_flags().is_static()) {
1173 Symbol* sig = fld.signature();
1174
1175 writer->write_symbolID(fld.name()); // name
1176 writer->write_u1(sig2tag(sig)); // type
1177 }
1178 }
1179 }
1180
1181 // creates HPROF_GC_INSTANCE_DUMP record for the given object
1182 void DumperSupport::dump_instance(AbstractDumpWriter* writer, oop o, DumperClassCacheTable* class_cache) {
1183 InstanceKlass* ik = InstanceKlass::cast(o->klass());
1184
1185 DumperClassCacheTableEntry* cache_entry = class_cache->lookup_or_create(ik);
1186
1187 u4 is = instance_size(ik, cache_entry);
1188 u4 size = 1 + sizeof(address) + 4 + sizeof(address) + 4 + is;
1189
1190 writer->start_sub_record(HPROF_GC_INSTANCE_DUMP, size);
1191 writer->write_objectID(o);
1192 writer->write_u4(STACK_TRACE_ID);
1193
1194 // class ID
1195 writer->write_classID(ik);
1196
1197 // number of bytes that follow
1198 writer->write_u4(is);
1199
1200 // field values
1201 dump_instance_fields(writer, o, cache_entry);
1202
1203 writer->end_sub_record();
1204 }
1205
1206 // creates HPROF_GC_CLASS_DUMP record for the given instance class
1207 void DumperSupport::dump_instance_class(AbstractDumpWriter* writer, InstanceKlass* ik) {
1208 // We can safepoint and do a heap dump at a point where we have a Klass,
1209 // but no java mirror class has been setup for it. So we need to check
1210 // that the class is at least loaded, to avoid crash from a null mirror.
1211 if (!ik->is_loaded()) {
1212 return;
1213 }
1214
1215 u2 static_fields_count = 0;
1216 u4 static_size = get_static_fields_size(ik, static_fields_count);
1217 u2 instance_fields_count = get_instance_fields_count(ik);
1218 u4 instance_fields_size = instance_fields_count * (sizeof(address) + 1);
1219 u4 size = checked_cast<u4>(1 + sizeof(address) + 4 + 6 * sizeof(address) + 4 + 2 + 2 + static_size + 2 + instance_fields_size);
1220
1221 writer->start_sub_record(HPROF_GC_CLASS_DUMP, size);
1222
1223 // class ID
1224 writer->write_classID(ik);
1225 writer->write_u4(STACK_TRACE_ID);
1226
1227 // super class ID
1228 InstanceKlass* super = ik->super();
1229 if (super == nullptr) {
1230 writer->write_objectID(oop(nullptr));
1231 } else {
1232 writer->write_classID(super);
1233 }
1234
1235 writer->write_objectID(ik->class_loader());
1236 writer->write_objectID(ik->signers());
1237 writer->write_objectID(ik->protection_domain());
1238
1239 // reserved
1240 writer->write_objectID(oop(nullptr));
1241 writer->write_objectID(oop(nullptr));
1242
1243 // instance size
1244 writer->write_u4(DumperSupport::instance_size(ik));
1245
1246 // size of constant pool - ignored by HAT 1.1
1247 writer->write_u2(0);
1248
1249 // static fields
1250 writer->write_u2(static_fields_count);
1251 dump_static_fields(writer, ik);
1252
1253 // description of instance fields
1254 writer->write_u2(instance_fields_count);
1255 dump_instance_field_descriptors(writer, ik);
1256
1257 writer->end_sub_record();
1258 }
1259
1260 // creates HPROF_GC_CLASS_DUMP record for the given array class
1261 void DumperSupport::dump_array_class(AbstractDumpWriter* writer, Klass* k) {
1262 InstanceKlass* ik = nullptr; // bottom class for object arrays, null for primitive type arrays
1263 if (k->is_objArray_klass()) {
1264 Klass *bk = ObjArrayKlass::cast(k)->bottom_klass();
1265 assert(bk != nullptr, "checking");
1266 if (bk->is_instance_klass()) {
1267 ik = InstanceKlass::cast(bk);
1268 }
1269 }
1270
1271 u4 size = 1 + sizeof(address) + 4 + 6 * sizeof(address) + 4 + 2 + 2 + 2;
1272 writer->start_sub_record(HPROF_GC_CLASS_DUMP, size);
1273 writer->write_classID(k);
1274 writer->write_u4(STACK_TRACE_ID);
1275
1276 // super class of array classes is java.lang.Object
1277 InstanceKlass* java_super = k->java_super();
1278 assert(java_super != nullptr, "checking");
1279 writer->write_classID(java_super);
1280
1281 writer->write_objectID(ik == nullptr ? oop(nullptr) : ik->class_loader());
1282 writer->write_objectID(ik == nullptr ? oop(nullptr) : ik->signers());
1283 writer->write_objectID(ik == nullptr ? oop(nullptr) : ik->protection_domain());
1284
1285 writer->write_objectID(oop(nullptr)); // reserved
1286 writer->write_objectID(oop(nullptr));
1287 writer->write_u4(0); // instance size
1288 writer->write_u2(0); // constant pool
1289 writer->write_u2(0); // static fields
1290 writer->write_u2(0); // instance fields
1291
1292 writer->end_sub_record();
1293
1294 }
1295
1296 // Hprof uses an u4 as record length field,
1297 // which means we need to truncate arrays that are too long.
1298 int DumperSupport::calculate_array_max_length(AbstractDumpWriter* writer, arrayOop array, short header_size) {
1299 BasicType type = ArrayKlass::cast(array->klass())->element_type();
1300 assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type");
1301
1302 int length = array->length();
1303
1304 int type_size;
1305 if (type == T_OBJECT) {
1306 type_size = sizeof(address);
1307 } else {
1308 type_size = type2aelembytes(type);
1309 }
1310
1311 size_t length_in_bytes = (size_t)length * type_size;
1312 uint max_bytes = max_juint - header_size;
1313
1314 if (length_in_bytes > max_bytes) {
1315 length = max_bytes / type_size;
1316 length_in_bytes = (size_t)length * type_size;
1317
1318 warning("cannot dump array of type %s[] with length %d; truncating to length %d",
1319 type2name_tab[type], array->length(), length);
1320 }
1321 return length;
1322 }
1323
1324 // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
1325 void DumperSupport::dump_object_array(AbstractDumpWriter* writer, objArrayOop array) {
1326 // sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID) + sizeof(classID)
1327 short header_size = 1 + 2 * 4 + 2 * sizeof(address);
1328 int length = calculate_array_max_length(writer, array, header_size);
1329 u4 size = checked_cast<u4>(header_size + length * sizeof(address));
1330
1331 writer->start_sub_record(HPROF_GC_OBJ_ARRAY_DUMP, size);
1332 writer->write_objectID(array);
1333 writer->write_u4(STACK_TRACE_ID);
1334 writer->write_u4(length);
1335
1336 // array class ID
1337 writer->write_classID(array->klass());
1338
1339 // [id]* elements
1340 for (int index = 0; index < length; index++) {
1341 oop o = array->obj_at(index);
1342 o = mask_dormant_archived_object(o, array);
1343 writer->write_objectID(o);
1344 }
1345
1346 writer->end_sub_record();
1347 }
1348
1349 #define WRITE_ARRAY(Array, Type, Size, Length) \
1350 for (int i = 0; i < Length; i++) { writer->write_##Size((Size)Array->Type##_at(i)); }
1351
1352 // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
1353 void DumperSupport::dump_prim_array(AbstractDumpWriter* writer, typeArrayOop array) {
1354 BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
1355 // 2 * sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID)
1356 short header_size = 2 * 1 + 2 * 4 + sizeof(address);
1357
1358 int length = calculate_array_max_length(writer, array, header_size);
1359 int type_size = type2aelembytes(type);
1360 u4 length_in_bytes = (u4)length * type_size;
1361 u4 size = header_size + length_in_bytes;
1362
1363 writer->start_sub_record(HPROF_GC_PRIM_ARRAY_DUMP, size);
1364 writer->write_objectID(array);
1365 writer->write_u4(STACK_TRACE_ID);
1366 writer->write_u4(length);
1367 writer->write_u1(type2tag(type));
1368
1369 // nothing to copy
1370 if (length == 0) {
1371 writer->end_sub_record();
1372 return;
1373 }
1374
1375 // If the byte ordering is big endian then we can copy most types directly
1376
1377 switch (type) {
1378 case T_INT : {
1379 if (Endian::is_Java_byte_ordering_different()) {
1380 WRITE_ARRAY(array, int, u4, length);
1381 } else {
1382 writer->write_raw(array->int_at_addr(0), length_in_bytes);
1383 }
1384 break;
1385 }
1386 case T_BYTE : {
1387 writer->write_raw(array->byte_at_addr(0), length_in_bytes);
1388 break;
1389 }
1390 case T_CHAR : {
1391 if (Endian::is_Java_byte_ordering_different()) {
1392 WRITE_ARRAY(array, char, u2, length);
1393 } else {
1394 writer->write_raw(array->char_at_addr(0), length_in_bytes);
1395 }
1396 break;
1397 }
1398 case T_SHORT : {
1399 if (Endian::is_Java_byte_ordering_different()) {
1400 WRITE_ARRAY(array, short, u2, length);
1401 } else {
1402 writer->write_raw(array->short_at_addr(0), length_in_bytes);
1403 }
1404 break;
1405 }
1406 case T_BOOLEAN : {
1407 if (Endian::is_Java_byte_ordering_different()) {
1408 WRITE_ARRAY(array, bool, u1, length);
1409 } else {
1410 writer->write_raw(array->bool_at_addr(0), length_in_bytes);
1411 }
1412 break;
1413 }
1414 case T_LONG : {
1415 if (Endian::is_Java_byte_ordering_different()) {
1416 WRITE_ARRAY(array, long, u8, length);
1417 } else {
1418 writer->write_raw(array->long_at_addr(0), length_in_bytes);
1419 }
1420 break;
1421 }
1422
1423 // handle float/doubles in a special value to ensure than NaNs are
1424 // written correctly. TO DO: Check if we can avoid this on processors that
1425 // use IEEE 754.
1426
1427 case T_FLOAT : {
1428 for (int i = 0; i < length; i++) {
1429 dump_float(writer, array->float_at(i));
1430 }
1431 break;
1432 }
1433 case T_DOUBLE : {
1434 for (int i = 0; i < length; i++) {
1435 dump_double(writer, array->double_at(i));
1436 }
1437 break;
1438 }
1439 default : ShouldNotReachHere();
1440 }
1441
1442 writer->end_sub_record();
1443 }
1444
1445 // create a HPROF_FRAME record of the given Method* and bci
1446 void DumperSupport::dump_stack_frame(AbstractDumpWriter* writer,
1447 int frame_serial_num,
1448 int class_serial_num,
1449 Method* m,
1450 int bci) {
1451 int line_number;
1452 if (m->is_native()) {
1453 line_number = -3; // native frame
1454 } else {
1455 line_number = m->line_number_from_bci(bci);
1456 }
1457
1458 write_header(writer, HPROF_FRAME, 4*oopSize + 2*sizeof(u4));
1459 writer->write_id(frame_serial_num); // frame serial number
1460 writer->write_symbolID(m->name()); // method's name
1461 writer->write_symbolID(m->signature()); // method's signature
1462
1463 assert(m->method_holder()->is_instance_klass(), "not InstanceKlass");
1464 writer->write_symbolID(m->method_holder()->source_file_name()); // source file name
1465 writer->write_u4(class_serial_num); // class serial number
1466 writer->write_u4((u4) line_number); // line number
1467 }
1468
1469
1470 // Support class used to generate HPROF_UTF8 records from the entries in the
1471 // SymbolTable.
1472
1473 class SymbolTableDumper : public SymbolClosure {
1474 private:
1475 AbstractDumpWriter* _writer;
1476 AbstractDumpWriter* writer() const { return _writer; }
1477 public:
1478 SymbolTableDumper(AbstractDumpWriter* writer) { _writer = writer; }
1479 void do_symbol(Symbol** p);
1480 };
1481
1482 void SymbolTableDumper::do_symbol(Symbol** p) {
1483 ResourceMark rm;
1484 Symbol* sym = *p;
1485 int len = sym->utf8_length();
1486 if (len > 0) {
1487 char* s = sym->as_utf8();
1488 DumperSupport::write_header(writer(), HPROF_UTF8, oopSize + len);
1489 writer()->write_symbolID(sym);
1490 writer()->write_raw(s, len);
1491 }
1492 }
1493
1494 // Support class used to generate HPROF_GC_CLASS_DUMP records
1495
1496 class ClassDumper : public KlassClosure {
1497 private:
1498 AbstractDumpWriter* _writer;
1499 AbstractDumpWriter* writer() const { return _writer; }
1500
1501 public:
1502 ClassDumper(AbstractDumpWriter* writer) : _writer(writer) {}
1503
1504 void do_klass(Klass* k) {
1505 if (k->is_instance_klass()) {
1506 DumperSupport::dump_instance_class(writer(), InstanceKlass::cast(k));
1507 } else {
1508 DumperSupport::dump_array_class(writer(), k);
1509 }
1510 }
1511 };
1512
1513 // Support class used to generate HPROF_LOAD_CLASS records
1514
1515 class LoadedClassDumper : public LockedClassesDo {
1516 private:
1517 AbstractDumpWriter* _writer;
1518 GrowableArray<Klass*>* _klass_map;
1519 u4 _class_serial_num;
1520 AbstractDumpWriter* writer() const { return _writer; }
1521 void add_class_serial_number(Klass* k, int serial_num) {
1522 _klass_map->at_put_grow(serial_num, k);
1523 }
1524 public:
1525 LoadedClassDumper(AbstractDumpWriter* writer, GrowableArray<Klass*>* klass_map)
1526 : _writer(writer), _klass_map(klass_map), _class_serial_num(0) {}
1527
1528 void do_klass(Klass* k) {
1529 // len of HPROF_LOAD_CLASS record
1530 u4 remaining = 2 * oopSize + 2 * sizeof(u4);
1531 DumperSupport::write_header(writer(), HPROF_LOAD_CLASS, remaining);
1532 // class serial number is just a number
1533 writer()->write_u4(++_class_serial_num);
1534 // class ID
1535 writer()->write_classID(k);
1536 // add the Klass* and class serial number pair
1537 add_class_serial_number(k, _class_serial_num);
1538 writer()->write_u4(STACK_TRACE_ID);
1539 // class name ID
1540 Symbol* name = k->name();
1541 writer()->write_symbolID(name);
1542 }
1543 };
1544
1545 // Support class used to generate HPROF_GC_ROOT_JNI_LOCAL records
1546
1547 class JNILocalsDumper : public OopClosure {
1548 private:
1549 AbstractDumpWriter* _writer;
1550 u4 _thread_serial_num;
1551 int _frame_num;
1552 AbstractDumpWriter* writer() const { return _writer; }
1553 public:
1554 JNILocalsDumper(AbstractDumpWriter* writer, u4 thread_serial_num) {
1555 _writer = writer;
1556 _thread_serial_num = thread_serial_num;
1557 _frame_num = -1; // default - empty stack
1558 }
1559 void set_frame_number(int n) { _frame_num = n; }
1560 void do_oop(oop* obj_p);
1561 void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1562 };
1563
1564 void JNILocalsDumper::do_oop(oop* obj_p) {
1565 // ignore null handles
1566 oop o = *obj_p;
1567 if (o != nullptr) {
1568 u4 size = 1 + sizeof(address) + 4 + 4;
1569 writer()->start_sub_record(HPROF_GC_ROOT_JNI_LOCAL, size);
1570 writer()->write_objectID(o);
1571 writer()->write_u4(_thread_serial_num);
1572 writer()->write_u4((u4)_frame_num);
1573 writer()->end_sub_record();
1574 }
1575 }
1576
1577
1578 // Support class used to generate HPROF_GC_ROOT_JNI_GLOBAL records
1579
1580 class JNIGlobalsDumper : public OopClosure {
1581 private:
1582 AbstractDumpWriter* _writer;
1583 AbstractDumpWriter* writer() const { return _writer; }
1584
1585 public:
1586 JNIGlobalsDumper(AbstractDumpWriter* writer) {
1587 _writer = writer;
1588 }
1589 void do_oop(oop* obj_p);
1590 void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1591 };
1592
1593 void JNIGlobalsDumper::do_oop(oop* obj_p) {
1594 oop o = NativeAccess<AS_NO_KEEPALIVE>::oop_load(obj_p);
1595
1596 // ignore these
1597 if (o == nullptr) return;
1598 // we ignore global ref to symbols and other internal objects
1599 if (o->is_instance() || o->is_objArray() || o->is_typeArray()) {
1600 u4 size = 1 + 2 * sizeof(address);
1601 writer()->start_sub_record(HPROF_GC_ROOT_JNI_GLOBAL, size);
1602 writer()->write_objectID(o);
1603 writer()->write_rootID(obj_p); // global ref ID
1604 writer()->end_sub_record();
1605 }
1606 };
1607
1608 // Support class used to generate HPROF_GC_ROOT_STICKY_CLASS records
1609
1610 class StickyClassDumper : public KlassClosure {
1611 private:
1612 AbstractDumpWriter* _writer;
1613 AbstractDumpWriter* writer() const { return _writer; }
1614 public:
1615 StickyClassDumper(AbstractDumpWriter* writer) {
1616 _writer = writer;
1617 }
1618 void do_klass(Klass* k) {
1619 if (k->is_instance_klass()) {
1620 InstanceKlass* ik = InstanceKlass::cast(k);
1621 u4 size = 1 + sizeof(address);
1622 writer()->start_sub_record(HPROF_GC_ROOT_STICKY_CLASS, size);
1623 writer()->write_classID(ik);
1624 writer()->end_sub_record();
1625 }
1626 }
1627 };
1628
1629 // Support class used to generate HPROF_GC_ROOT_JAVA_FRAME records.
1630
1631 class JavaStackRefDumper : public StackObj {
1632 private:
1633 AbstractDumpWriter* _writer;
1634 u4 _thread_serial_num;
1635 int _frame_num;
1636 AbstractDumpWriter* writer() const { return _writer; }
1637 public:
1638 JavaStackRefDumper(AbstractDumpWriter* writer, u4 thread_serial_num)
1639 : _writer(writer), _thread_serial_num(thread_serial_num), _frame_num(-1) // default - empty stack
1640 {
1641 }
1642
1643 void set_frame_number(int n) { _frame_num = n; }
1644
1645 void dump_java_stack_refs(StackValueCollection* values);
1646 };
1647
1648 void JavaStackRefDumper::dump_java_stack_refs(StackValueCollection* values) {
1649 for (int index = 0; index < values->size(); index++) {
1650 if (values->at(index)->type() == T_OBJECT) {
1651 oop o = values->obj_at(index)();
1652 if (o != nullptr) {
1653 u4 size = 1 + sizeof(address) + 4 + 4;
1654 writer()->start_sub_record(HPROF_GC_ROOT_JAVA_FRAME, size);
1655 writer()->write_objectID(o);
1656 writer()->write_u4(_thread_serial_num);
1657 writer()->write_u4((u4)_frame_num);
1658 writer()->end_sub_record();
1659 }
1660 }
1661 }
1662 }
1663
1664 // Class to collect, store and dump thread-related data:
1665 // - HPROF_TRACE and HPROF_FRAME records;
1666 // - HPROF_GC_ROOT_THREAD_OBJ/HPROF_GC_ROOT_JAVA_FRAME/HPROF_GC_ROOT_JNI_LOCAL subrecords.
1667 class ThreadDumper : public CHeapObj<mtInternal> {
1668 public:
1669 enum class ThreadType { Platform, MountedVirtual, UnmountedVirtual };
1670
1671 private:
1672 ThreadType _thread_type;
1673 JavaThread* _java_thread;
1674 oop _thread_oop;
1675
1676 GrowableArray<StackFrameInfo*>* _frames;
1677 // non-null if the thread is OOM thread
1678 Method* _oome_constructor;
1679 int _thread_serial_num;
1680 int _start_frame_serial_num;
1681
1682 vframe* get_top_frame() const;
1683
1684 public:
1685 static bool should_dump_pthread(JavaThread* thread) {
1686 return thread->threadObj() != nullptr && !thread->is_exiting() && !thread->is_hidden_from_external_view();
1687 }
1688
1689 static bool should_dump_vthread(oop vt) {
1690 return java_lang_VirtualThread::state(vt) != java_lang_VirtualThread::NEW
1691 && java_lang_VirtualThread::state(vt) != java_lang_VirtualThread::TERMINATED;
1692 }
1693
1694 static bool is_vthread_mounted(oop vt) {
1695 // The code should be consistent with the "mounted virtual thread" case
1696 // (VM_HeapDumper::dump_stack_traces(), ThreadDumper::get_top_frame()).
1697 // I.e. virtual thread is mounted if its carrierThread is not null
1698 // and is_vthread_mounted() for the carrier thread returns true.
1699 oop carrier_thread = java_lang_VirtualThread::carrier_thread(vt);
1700 if (carrier_thread == nullptr) {
1701 return false;
1702 }
1703 JavaThread* java_thread = java_lang_Thread::thread(carrier_thread);
1704 return java_thread->is_vthread_mounted();
1705 }
1706
1707 ThreadDumper(ThreadType thread_type, JavaThread* java_thread, oop thread_oop);
1708 ~ThreadDumper() {
1709 for (int index = 0; index < _frames->length(); index++) {
1710 delete _frames->at(index);
1711 }
1712 delete _frames;
1713 }
1714
1715 // affects frame_count
1716 void add_oom_frame(Method* oome_constructor) {
1717 assert(_start_frame_serial_num == 0, "add_oom_frame cannot be called after init_serial_nums");
1718 _oome_constructor = oome_constructor;
1719 }
1720
1721 void init_serial_nums(volatile int* thread_counter, volatile int* frame_counter) {
1722 assert(_start_frame_serial_num == 0, "already initialized");
1723 _thread_serial_num = AtomicAccess::fetch_then_add(thread_counter, 1);
1724 _start_frame_serial_num = AtomicAccess::fetch_then_add(frame_counter, frame_count());
1725 }
1726
1727 bool oom_thread() const {
1728 return _oome_constructor != nullptr;
1729 }
1730
1731 int frame_count() const {
1732 return _frames->length() + (oom_thread() ? 1 : 0);
1733 }
1734
1735 u4 thread_serial_num() const {
1736 return (u4)_thread_serial_num;
1737 }
1738
1739 u4 stack_trace_serial_num() const {
1740 return (u4)(_thread_serial_num + STACK_TRACE_ID);
1741 }
1742
1743 // writes HPROF_TRACE and HPROF_FRAME records
1744 // returns number of dumped frames
1745 void dump_stack_traces(AbstractDumpWriter* writer, GrowableArray<Klass*>* klass_map);
1746
1747 // writes HPROF_GC_ROOT_THREAD_OBJ subrecord
1748 void dump_thread_obj(AbstractDumpWriter* writer);
1749
1750 // Walk the stack of the thread.
1751 // Dumps a HPROF_GC_ROOT_JAVA_FRAME subrecord for each local
1752 // Dumps a HPROF_GC_ROOT_JNI_LOCAL subrecord for each JNI local
1753 void dump_stack_refs(AbstractDumpWriter* writer);
1754
1755 };
1756
1757 ThreadDumper::ThreadDumper(ThreadType thread_type, JavaThread* java_thread, oop thread_oop)
1758 : _thread_type(thread_type), _java_thread(java_thread), _thread_oop(thread_oop),
1759 _oome_constructor(nullptr),
1760 _thread_serial_num(0), _start_frame_serial_num(0)
1761 {
1762 // sanity checks
1763 if (_thread_type == ThreadType::UnmountedVirtual) {
1764 assert(_java_thread == nullptr, "sanity");
1765 assert(_thread_oop != nullptr, "sanity");
1766 } else {
1767 assert(_java_thread != nullptr, "sanity");
1768 assert(_thread_oop != nullptr, "sanity");
1769 }
1770
1771 _frames = new (mtServiceability) GrowableArray<StackFrameInfo*>(10, mtServiceability);
1772 bool stop_at_vthread_entry = _thread_type == ThreadType::MountedVirtual;
1773
1774 // vframes are resource allocated
1775 Thread* current_thread = Thread::current();
1776 ResourceMark rm(current_thread);
1777 HandleMark hm(current_thread);
1778
1779 for (vframe* vf = get_top_frame(); vf != nullptr; vf = vf->sender()) {
1780 if (stop_at_vthread_entry && vf->is_vthread_entry()) {
1781 break;
1782 }
1783 if (vf->is_java_frame()) {
1784 javaVFrame* jvf = javaVFrame::cast(vf);
1785 _frames->append(new StackFrameInfo(jvf, false));
1786 } else {
1787 // ignore non-Java frames
1788 }
1789 }
1790 }
1791
1792 void ThreadDumper::dump_stack_traces(AbstractDumpWriter* writer, GrowableArray<Klass*>* klass_map) {
1793 assert(_thread_serial_num != 0 && _start_frame_serial_num != 0, "serial_nums are not initialized");
1794
1795 // write HPROF_FRAME records for this thread's stack trace
1796 int depth = _frames->length();
1797 int frame_serial_num = _start_frame_serial_num;
1798
1799 if (oom_thread()) {
1800 // OOM thread
1801 // write fake frame that makes it look like the thread, which caused OOME,
1802 // is in the OutOfMemoryError zero-parameter constructor
1803 int oome_serial_num = klass_map->find(_oome_constructor->method_holder());
1804 // the class serial number starts from 1
1805 assert(oome_serial_num > 0, "OutOfMemoryError class not found");
1806 DumperSupport::dump_stack_frame(writer, ++frame_serial_num, oome_serial_num, _oome_constructor, 0);
1807 depth++;
1808 }
1809
1810 for (int j = 0; j < _frames->length(); j++) {
1811 StackFrameInfo* frame = _frames->at(j);
1812 Method* m = frame->method();
1813 int class_serial_num = klass_map->find(m->method_holder());
1814 // the class serial number starts from 1
1815 assert(class_serial_num > 0, "class not found");
1816 DumperSupport::dump_stack_frame(writer, ++frame_serial_num, class_serial_num, m, frame->bci());
1817 }
1818
1819 // write HPROF_TRACE record for the thread
1820 DumperSupport::write_header(writer, HPROF_TRACE, checked_cast<u4>(3 * sizeof(u4) + depth * oopSize));
1821 writer->write_u4(stack_trace_serial_num()); // stack trace serial number
1822 writer->write_u4(thread_serial_num()); // thread serial number
1823 writer->write_u4((u4)depth); // frame count (including oom frame)
1824 for (int j = 1; j <= depth; j++) {
1825 writer->write_id(_start_frame_serial_num + j);
1826 }
1827 }
1828
1829 void ThreadDumper::dump_thread_obj(AbstractDumpWriter * writer) {
1830 assert(_thread_serial_num != 0 && _start_frame_serial_num != 0, "serial_num is not initialized");
1831
1832 u4 size = 1 + sizeof(address) + 4 + 4;
1833 writer->start_sub_record(HPROF_GC_ROOT_THREAD_OBJ, size);
1834 writer->write_objectID(_thread_oop);
1835 writer->write_u4(thread_serial_num()); // thread serial number
1836 writer->write_u4(stack_trace_serial_num()); // stack trace serial number
1837 writer->end_sub_record();
1838 }
1839
1840 void ThreadDumper::dump_stack_refs(AbstractDumpWriter * writer) {
1841 assert(_thread_serial_num != 0 && _start_frame_serial_num != 0, "serial_num is not initialized");
1842
1843 JNILocalsDumper blk(writer, thread_serial_num());
1844 if (_thread_type == ThreadType::Platform) {
1845 if (!_java_thread->has_last_Java_frame()) {
1846 // no last java frame but there may be JNI locals
1847 _java_thread->active_handles()->oops_do(&blk);
1848 return;
1849 }
1850 }
1851
1852 JavaStackRefDumper java_ref_dumper(writer, thread_serial_num());
1853
1854 // vframes are resource allocated
1855 Thread* current_thread = Thread::current();
1856 ResourceMark rm(current_thread);
1857 HandleMark hm(current_thread);
1858
1859 bool stopAtVthreadEntry = _thread_type == ThreadType::MountedVirtual;
1860 frame* last_entry_frame = nullptr;
1861 bool is_top_frame = true;
1862 int depth = 0;
1863 if (oom_thread()) {
1864 depth++;
1865 }
1866
1867 for (vframe* vf = get_top_frame(); vf != nullptr; vf = vf->sender()) {
1868 if (stopAtVthreadEntry && vf->is_vthread_entry()) {
1869 break;
1870 }
1871
1872 if (vf->is_java_frame()) {
1873 javaVFrame* jvf = javaVFrame::cast(vf);
1874 if (!(jvf->method()->is_native())) {
1875 java_ref_dumper.set_frame_number(depth);
1876 java_ref_dumper.dump_java_stack_refs(jvf->locals());
1877 java_ref_dumper.dump_java_stack_refs(jvf->expressions());
1878 } else {
1879 // native frame
1880 blk.set_frame_number(depth);
1881 if (is_top_frame) {
1882 // JNI locals for the top frame if mounted
1883 assert(_java_thread != nullptr || jvf->method()->is_synchronized()
1884 || jvf->method()->is_object_wait0(), "impossible for unmounted vthread");
1885 if (_java_thread != nullptr) {
1886 _java_thread->active_handles()->oops_do(&blk);
1887 }
1888 } else {
1889 if (last_entry_frame != nullptr) {
1890 // JNI locals for the entry frame
1891 assert(last_entry_frame->is_entry_frame(), "checking");
1892 last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(&blk);
1893 }
1894 }
1895 }
1896 last_entry_frame = nullptr;
1897 // increment only for Java frames
1898 depth++;
1899 } else {
1900 // externalVFrame - for an entry frame then we report the JNI locals
1901 // when we find the corresponding javaVFrame
1902 frame* fr = vf->frame_pointer();
1903 assert(fr != nullptr, "sanity check");
1904 if (fr->is_entry_frame()) {
1905 last_entry_frame = fr;
1906 }
1907 }
1908 is_top_frame = false;
1909 }
1910 assert(depth == frame_count(), "total number of Java frames not matched");
1911 }
1912
1913 vframe* ThreadDumper::get_top_frame() const {
1914 if (_thread_type == ThreadType::UnmountedVirtual) {
1915 ContinuationWrapper cont(java_lang_VirtualThread::continuation(_thread_oop));
1916 if (cont.is_empty()) {
1917 return nullptr;
1918 }
1919 assert(!cont.is_mounted(), "sanity check");
1920 stackChunkOop chunk = cont.last_nonempty_chunk();
1921 if (chunk == nullptr || chunk->is_empty()) {
1922 return nullptr;
1923 }
1924
1925 RegisterMap reg_map(cont.continuation(), RegisterMap::UpdateMap::include);
1926 frame fr = chunk->top_frame(®_map);
1927 vframe* vf = vframe::new_vframe(&fr, ®_map, nullptr); // don't need JavaThread
1928 return vf;
1929 }
1930
1931 RegisterMap reg_map(_java_thread,
1932 RegisterMap::UpdateMap::include,
1933 RegisterMap::ProcessFrames::include,
1934 RegisterMap::WalkContinuation::skip);
1935 switch (_thread_type) {
1936 case ThreadType::Platform:
1937 if (!_java_thread->has_last_Java_frame()) {
1938 return nullptr;
1939 }
1940 return _java_thread->is_vthread_mounted()
1941 ? _java_thread->carrier_last_java_vframe(®_map)
1942 : _java_thread->platform_thread_last_java_vframe(®_map);
1943
1944 case ThreadType::MountedVirtual:
1945 return _java_thread->last_java_vframe(®_map);
1946
1947 default: // make compilers happy
1948 break;
1949 }
1950 ShouldNotReachHere();
1951 return nullptr;
1952 }
1953
1954 // Callback to dump thread-related data for unmounted virtual threads;
1955 // implemented by VM_HeapDumper.
1956 class UnmountedVThreadDumper {
1957 public:
1958 virtual void dump_vthread(oop vt, AbstractDumpWriter* segment_writer) = 0;
1959 };
1960
1961 // Support class used when iterating over the heap.
1962 class HeapObjectDumper : public ObjectClosure {
1963 private:
1964 AbstractDumpWriter* _writer;
1965 AbstractDumpWriter* writer() { return _writer; }
1966 UnmountedVThreadDumper* _vthread_dumper;
1967
1968 DumperClassCacheTable _class_cache;
1969
1970 public:
1971 HeapObjectDumper(AbstractDumpWriter* writer, UnmountedVThreadDumper* vthread_dumper)
1972 : _writer(writer), _vthread_dumper(vthread_dumper) {}
1973
1974 // called for each object in the heap
1975 void do_object(oop o);
1976 };
1977
1978 void HeapObjectDumper::do_object(oop o) {
1979 // skip classes as these emitted as HPROF_GC_CLASS_DUMP records
1980 if (o->klass() == vmClasses::Class_klass()) {
1981 if (!java_lang_Class::is_primitive(o)) {
1982 return;
1983 }
1984 }
1985
1986 if (DumperSupport::mask_dormant_archived_object(o, nullptr) == nullptr) {
1987 return;
1988 }
1989
1990 if (o->is_instance()) {
1991 // create a HPROF_GC_INSTANCE record for each object
1992 DumperSupport::dump_instance(writer(), o, &_class_cache);
1993 // If we encounter an unmounted virtual thread it needs to be dumped explicitly
1994 // (mounted virtual threads are dumped with their carriers).
1995 if (java_lang_VirtualThread::is_instance(o)
1996 && ThreadDumper::should_dump_vthread(o) && !ThreadDumper::is_vthread_mounted(o)) {
1997 _vthread_dumper->dump_vthread(o, writer());
1998 }
1999 } else if (o->is_objArray()) {
2000 // create a HPROF_GC_OBJ_ARRAY_DUMP record for each object array
2001 DumperSupport::dump_object_array(writer(), objArrayOop(o));
2002 } else if (o->is_typeArray()) {
2003 // create a HPROF_GC_PRIM_ARRAY_DUMP record for each type array
2004 DumperSupport::dump_prim_array(writer(), typeArrayOop(o));
2005 }
2006 }
2007
2008 // The dumper controller for parallel heap dump
2009 class DumperController : public CHeapObj<mtInternal> {
2010 private:
2011 Monitor* _lock;
2012 Mutex* _global_writer_lock;
2013
2014 const uint _dumper_number;
2015 uint _complete_number;
2016
2017 bool _started; // VM dumper started and acquired global writer lock
2018
2019 public:
2020 DumperController(uint number) :
2021 // _lock and _global_writer_lock are used for synchronization between GC worker threads inside safepoint,
2022 // so we lock with _no_safepoint_check_flag.
2023 // signal_start() acquires _lock when global writer is locked,
2024 // its rank must be less than _global_writer_lock rank.
2025 _lock(new (std::nothrow) PaddedMonitor(Mutex::nosafepoint - 1, "DumperController_lock")),
2026 _global_writer_lock(new (std::nothrow) Mutex(Mutex::nosafepoint, "DumpWriter_lock")),
2027 _dumper_number(number),
2028 _complete_number(0),
2029 _started(false)
2030 {}
2031
2032 ~DumperController() {
2033 delete _lock;
2034 delete _global_writer_lock;
2035 }
2036
2037 // parallel (non VM) dumpers must wait until VM dumper acquires global writer lock
2038 void wait_for_start_signal() {
2039 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
2040 while (_started == false) {
2041 ml.wait();
2042 }
2043 }
2044
2045 void signal_start() {
2046 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
2047 _started = true;
2048 ml.notify_all();
2049 }
2050
2051 void lock_global_writer() {
2052 _global_writer_lock->lock_without_safepoint_check();
2053 }
2054
2055 void unlock_global_writer() {
2056 _global_writer_lock->unlock();
2057 }
2058
2059 void dumper_complete(DumpWriter* local_writer, DumpWriter* global_writer) {
2060 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
2061 _complete_number++;
2062 // propagate local error to global if any
2063 if (local_writer->has_error()) {
2064 global_writer->set_error(local_writer->error());
2065 }
2066 ml.notify();
2067 }
2068
2069 void wait_all_dumpers_complete() {
2070 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
2071 while (_complete_number != _dumper_number) {
2072 ml.wait();
2073 }
2074 }
2075 };
2076
2077 // DumpMerger merges separate dump files into a complete one
2078 class DumpMerger : public StackObj {
2079 private:
2080 DumpWriter* _writer;
2081 const char* _path;
2082 bool _has_error;
2083 int _dump_seq;
2084
2085 private:
2086 void merge_file(const char* path);
2087 void merge_done();
2088 void set_error(const char* msg);
2089
2090 public:
2091 DumpMerger(const char* path, DumpWriter* writer, int dump_seq) :
2092 _writer(writer),
2093 _path(path),
2094 _has_error(_writer->has_error()),
2095 _dump_seq(dump_seq) {}
2096
2097 void do_merge();
2098
2099 // returns path for the parallel DumpWriter (resource allocated)
2100 static char* get_writer_path(const char* base_path, int seq);
2101
2102 };
2103
2104 char* DumpMerger::get_writer_path(const char* base_path, int seq) {
2105 // approximate required buffer size
2106 size_t buf_size = strlen(base_path)
2107 + 2 // ".p"
2108 + 10 // number (that's enough for 2^32 parallel dumpers)
2109 + 1; // '\0'
2110
2111 char* path = NEW_RESOURCE_ARRAY(char, buf_size);
2112 memset(path, 0, buf_size);
2113
2114 os::snprintf_checked(path, buf_size, "%s.p%d", base_path, seq);
2115
2116 return path;
2117 }
2118
2119
2120 void DumpMerger::merge_done() {
2121 // Writes the HPROF_HEAP_DUMP_END record.
2122 if (!_has_error) {
2123 DumperSupport::end_of_dump(_writer);
2124 _writer->flush();
2125 }
2126 _dump_seq = 0; //reset
2127 }
2128
2129 void DumpMerger::set_error(const char* msg) {
2130 assert(msg != nullptr, "sanity check");
2131 log_error(heapdump)("%s (file: %s)", msg, _path);
2132 _writer->set_error(msg);
2133 _has_error = true;
2134 }
2135
2136 #ifdef LINUX
2137 // Merge segmented heap files via sendfile, it's more efficient than the
2138 // read+write combination, which would require transferring data to and from
2139 // user space.
2140 void DumpMerger::merge_file(const char* path) {
2141 TraceTime timer("Merge segmented heap file directly", TRACETIME_LOG(Info, heapdump));
2142
2143 int segment_fd = os::open(path, O_RDONLY, 0);
2144 if (segment_fd == -1) {
2145 set_error("Can not open segmented heap file during merging");
2146 return;
2147 }
2148
2149 struct stat st;
2150 if (os::stat(path, &st) != 0) {
2151 ::close(segment_fd);
2152 set_error("Can not get segmented heap file size during merging");
2153 return;
2154 }
2155
2156 // A successful call to sendfile may write fewer bytes than requested; the
2157 // caller should be prepared to retry the call if there were unsent bytes.
2158 jlong offset = 0;
2159 while (offset < st.st_size) {
2160 int ret = os::Linux::sendfile(_writer->get_fd(), segment_fd, &offset, st.st_size);
2161 if (ret == -1) {
2162 ::close(segment_fd);
2163 set_error("Failed to merge segmented heap file");
2164 return;
2165 }
2166 }
2167
2168 // As sendfile variant does not call the write method of the global writer,
2169 // bytes_written is also incorrect for this variant, we need to explicitly
2170 // accumulate bytes_written for the global writer in this case
2171 julong accum = _writer->bytes_written() + st.st_size;
2172 _writer->set_bytes_written(accum);
2173 ::close(segment_fd);
2174 }
2175 #else
2176 // Generic implementation using read+write
2177 void DumpMerger::merge_file(const char* path) {
2178 TraceTime timer("Merge segmented heap file", TRACETIME_LOG(Info, heapdump));
2179
2180 fileStream segment_fs(path, "rb");
2181 if (!segment_fs.is_open()) {
2182 set_error("Can not open segmented heap file during merging");
2183 return;
2184 }
2185
2186 jlong total = 0;
2187 size_t cnt = 0;
2188
2189 // Use _writer buffer for reading.
2190 while ((cnt = segment_fs.read(_writer->buffer(), 1, _writer->buffer_size())) != 0) {
2191 _writer->set_position(cnt);
2192 _writer->flush();
2193 total += cnt;
2194 }
2195
2196 if (segment_fs.fileSize() != total) {
2197 set_error("Merged heap dump is incomplete");
2198 }
2199 }
2200 #endif
2201
2202 void DumpMerger::do_merge() {
2203 TraceTime timer("Merge heap files complete", TRACETIME_LOG(Info, heapdump));
2204
2205 // Since contents in segmented heap file were already zipped, we don't need to zip
2206 // them again during merging.
2207 AbstractCompressor* saved_compressor = _writer->compressor();
2208 _writer->set_compressor(nullptr);
2209
2210 // Merge the content of the remaining files into base file. Regardless of whether
2211 // the merge process is successful or not, these segmented files will be deleted.
2212 for (int i = 0; i < _dump_seq; i++) {
2213 ResourceMark rm;
2214 const char* path = get_writer_path(_path, i);
2215 if (!_has_error) {
2216 merge_file(path);
2217 }
2218 // Delete selected segmented heap file nevertheless
2219 if (remove(path) != 0) {
2220 log_info(heapdump)("Removal of segment file (%d) failed (%d)", i, errno);
2221 }
2222 }
2223
2224 // restore compressor for further use
2225 _writer->set_compressor(saved_compressor);
2226 merge_done();
2227 }
2228
2229 // The VM operation that performs the heap dump
2230 class VM_HeapDumper : public VM_GC_Operation, public WorkerTask, public UnmountedVThreadDumper {
2231 private:
2232 DumpWriter* _writer;
2233 JavaThread* _oome_thread;
2234 Method* _oome_constructor;
2235 bool _gc_before_heap_dump;
2236 GrowableArray<Klass*>* _klass_map;
2237
2238 ThreadDumper** _thread_dumpers; // platform, carrier and mounted virtual threads
2239 int _thread_dumpers_count;
2240 volatile int _thread_serial_num;
2241 volatile int _frame_serial_num;
2242
2243 volatile int _dump_seq;
2244 // parallel heap dump support
2245 uint _num_dumper_threads;
2246 DumperController* _dumper_controller;
2247 ParallelObjectIterator* _poi;
2248
2249 // Dumper id of VMDumper thread.
2250 static const int VMDumperId = 0;
2251 // VM dumper dumps both heap and non-heap data, other dumpers dump heap-only data.
2252 static bool is_vm_dumper(int dumper_id) { return dumper_id == VMDumperId; }
2253 // the 1st dumper calling get_next_dumper_id becomes VM dumper
2254 int get_next_dumper_id() {
2255 return AtomicAccess::fetch_then_add(&_dump_seq, 1);
2256 }
2257
2258 DumpWriter* writer() const { return _writer; }
2259
2260 bool skip_operation() const;
2261
2262 // HPROF_GC_ROOT_THREAD_OBJ records for platform and mounted virtual threads
2263 void dump_threads(AbstractDumpWriter* writer);
2264
2265 bool is_oom_thread(JavaThread* thread) const {
2266 return thread == _oome_thread && _oome_constructor != nullptr;
2267 }
2268
2269 // HPROF_TRACE and HPROF_FRAME records for platform and mounted virtual threads
2270 void dump_stack_traces(AbstractDumpWriter* writer);
2271
2272 public:
2273 VM_HeapDumper(DumpWriter* writer, bool gc_before_heap_dump, bool oome, uint num_dump_threads) :
2274 VM_GC_Operation(0 /* total collections, dummy, ignored */,
2275 GCCause::_heap_dump /* GC Cause */,
2276 0 /* total full collections, dummy, ignored */,
2277 gc_before_heap_dump),
2278 WorkerTask("dump heap") {
2279 _writer = writer;
2280 _gc_before_heap_dump = gc_before_heap_dump;
2281 _klass_map = new (mtServiceability) GrowableArray<Klass*>(INITIAL_CLASS_COUNT, mtServiceability);
2282
2283 _thread_dumpers = nullptr;
2284 _thread_dumpers_count = 0;
2285 _thread_serial_num = 1;
2286 _frame_serial_num = 1;
2287
2288 _dump_seq = VMDumperId;
2289 _num_dumper_threads = num_dump_threads;
2290 _dumper_controller = nullptr;
2291 _poi = nullptr;
2292 if (oome) {
2293 assert(!Thread::current()->is_VM_thread(), "Dump from OutOfMemoryError cannot be called by the VMThread");
2294 // get OutOfMemoryError zero-parameter constructor
2295 InstanceKlass* oome_ik = vmClasses::OutOfMemoryError_klass();
2296 _oome_constructor = oome_ik->find_method(vmSymbols::object_initializer_name(),
2297 vmSymbols::void_method_signature());
2298 // get thread throwing OOME when generating the heap dump at OOME
2299 _oome_thread = JavaThread::current();
2300 } else {
2301 _oome_thread = nullptr;
2302 _oome_constructor = nullptr;
2303 }
2304 }
2305
2306 ~VM_HeapDumper() {
2307 if (_thread_dumpers != nullptr) {
2308 for (int i = 0; i < _thread_dumpers_count; i++) {
2309 delete _thread_dumpers[i];
2310 }
2311 FREE_C_HEAP_ARRAY(ThreadDumper*, _thread_dumpers);
2312 }
2313
2314 if (_dumper_controller != nullptr) {
2315 delete _dumper_controller;
2316 _dumper_controller = nullptr;
2317 }
2318 delete _klass_map;
2319 }
2320 int dump_seq() { return _dump_seq; }
2321 bool is_parallel_dump() { return _num_dumper_threads > 1; }
2322 void prepare_parallel_dump(WorkerThreads* workers);
2323
2324 VMOp_Type type() const { return VMOp_HeapDumper; }
2325 virtual bool doit_prologue();
2326 void doit();
2327 void work(uint worker_id);
2328
2329 // UnmountedVThreadDumper implementation
2330 void dump_vthread(oop vt, AbstractDumpWriter* segment_writer);
2331 };
2332
2333 bool VM_HeapDumper::skip_operation() const {
2334 return false;
2335 }
2336
2337 // fixes up the current dump record and writes HPROF_HEAP_DUMP_END record
2338 void DumperSupport::end_of_dump(AbstractDumpWriter* writer) {
2339 writer->finish_dump_segment();
2340
2341 writer->write_u1(HPROF_HEAP_DUMP_END);
2342 writer->write_u4(0);
2343 writer->write_u4(0);
2344 }
2345
2346 // Write a HPROF_GC_ROOT_THREAD_OBJ record for platform/carrier and mounted virtual threads.
2347 // Then walk the stack so that locals and JNI locals are dumped.
2348 void VM_HeapDumper::dump_threads(AbstractDumpWriter* writer) {
2349 for (int i = 0; i < _thread_dumpers_count; i++) {
2350 _thread_dumpers[i]->dump_thread_obj(writer);
2351 _thread_dumpers[i]->dump_stack_refs(writer);
2352 }
2353 }
2354
2355 bool VM_HeapDumper::doit_prologue() {
2356 if (_gc_before_heap_dump && (UseZGC || UseShenandoahGC)) {
2357 // ZGC and Shenandoah cannot perform a synchronous GC cycle from within the VM thread.
2358 // So collect_as_vm_thread() is a noop. To respect the _gc_before_heap_dump flag a
2359 // synchronous GC cycle is performed from the caller thread in the prologue.
2360 Universe::heap()->collect(GCCause::_heap_dump);
2361 }
2362 return VM_GC_Operation::doit_prologue();
2363 }
2364
2365 void VM_HeapDumper::prepare_parallel_dump(WorkerThreads* workers) {
2366 uint num_active_workers = workers != nullptr ? workers->active_workers() : 0;
2367 uint num_requested_dump_threads = _num_dumper_threads;
2368 // check if we can dump in parallel based on requested and active threads
2369 if (num_active_workers <= 1 || num_requested_dump_threads <= 1) {
2370 _num_dumper_threads = 1;
2371 } else {
2372 _num_dumper_threads = clamp(num_requested_dump_threads, 2U, num_active_workers);
2373 }
2374 _dumper_controller = new (std::nothrow) DumperController(_num_dumper_threads);
2375 bool can_parallel = _num_dumper_threads > 1;
2376 log_info(heapdump)("Requested dump threads %u, active dump threads %u, "
2377 "actual dump threads %u, parallelism %s",
2378 num_requested_dump_threads, num_active_workers,
2379 _num_dumper_threads, can_parallel ? "true" : "false");
2380 }
2381
2382 // The VM operation that dumps the heap. The dump consists of the following
2383 // records:
2384 //
2385 // HPROF_HEADER
2386 // [HPROF_UTF8]*
2387 // [HPROF_LOAD_CLASS]*
2388 // [[HPROF_FRAME]*|HPROF_TRACE]*
2389 // [HPROF_GC_CLASS_DUMP]*
2390 // [HPROF_HEAP_DUMP_SEGMENT]*
2391 // HPROF_HEAP_DUMP_END
2392 //
2393 // The HPROF_TRACE records represent the stack traces where the heap dump
2394 // is generated and a "dummy trace" record which does not include
2395 // any frames. The dummy trace record is used to be referenced as the
2396 // unknown object alloc site.
2397 //
2398 // Each HPROF_HEAP_DUMP_SEGMENT record has a length followed by sub-records.
2399 // To allow the heap dump be generated in a single pass we remember the position
2400 // of the dump length and fix it up after all sub-records have been written.
2401 // To generate the sub-records we iterate over the heap, writing
2402 // HPROF_GC_INSTANCE_DUMP, HPROF_GC_OBJ_ARRAY_DUMP, and HPROF_GC_PRIM_ARRAY_DUMP
2403 // records as we go. Once that is done we write records for some of the GC
2404 // roots.
2405
2406 void VM_HeapDumper::doit() {
2407
2408 CollectedHeap* ch = Universe::heap();
2409
2410 ch->ensure_parsability(false); // must happen, even if collection does
2411 // not happen (e.g. due to GCLocker)
2412
2413 if (_gc_before_heap_dump) {
2414 if (GCLocker::is_active()) {
2415 warning("GC locker is held; pre-heapdump GC was skipped");
2416 } else {
2417 ch->collect_as_vm_thread(GCCause::_heap_dump);
2418 }
2419 }
2420
2421 WorkerThreads* workers = ch->safepoint_workers();
2422 prepare_parallel_dump(workers);
2423
2424 if (!is_parallel_dump()) {
2425 work(VMDumperId);
2426 } else {
2427 ParallelObjectIterator poi(_num_dumper_threads);
2428 _poi = &poi;
2429 workers->run_task(this, _num_dumper_threads);
2430 _poi = nullptr;
2431 }
2432 }
2433
2434 void VM_HeapDumper::work(uint worker_id) {
2435 // VM Dumper works on all non-heap data dumping and part of heap iteration.
2436 int dumper_id = get_next_dumper_id();
2437
2438 if (is_vm_dumper(dumper_id)) {
2439 // lock global writer, it will be unlocked after VM Dumper finishes with non-heap data
2440 _dumper_controller->lock_global_writer();
2441 _dumper_controller->signal_start();
2442 } else {
2443 _dumper_controller->wait_for_start_signal();
2444 }
2445
2446 if (is_vm_dumper(dumper_id)) {
2447 TraceTime timer("Dump non-objects", TRACETIME_LOG(Info, heapdump));
2448 // Write the file header - we always use 1.0.2
2449 const char* header = "JAVA PROFILE 1.0.2";
2450
2451 // header is few bytes long - no chance to overflow int
2452 writer()->write_raw(header, strlen(header) + 1); // NUL terminated
2453 writer()->write_u4(oopSize);
2454 // timestamp is current time in ms
2455 writer()->write_u8(os::javaTimeMillis());
2456 // HPROF_UTF8 records
2457 SymbolTableDumper sym_dumper(writer());
2458 SymbolTable::symbols_do(&sym_dumper);
2459
2460 // write HPROF_LOAD_CLASS records
2461 {
2462 LoadedClassDumper loaded_class_dumper(writer(), _klass_map);
2463 ClassLoaderDataGraph::classes_do(&loaded_class_dumper);
2464 }
2465
2466 // write HPROF_FRAME and HPROF_TRACE records
2467 // this must be called after _klass_map is built when iterating the classes above.
2468 dump_stack_traces(writer());
2469
2470 // unlock global writer, so parallel dumpers can dump stack traces of unmounted virtual threads
2471 _dumper_controller->unlock_global_writer();
2472 }
2473
2474 // HPROF_HEAP_DUMP/HPROF_HEAP_DUMP_SEGMENT starts here
2475
2476 ResourceMark rm;
2477 // share global compressor, local DumpWriter is not responsible for its life cycle
2478 DumpWriter segment_writer(DumpMerger::get_writer_path(writer()->get_file_path(), dumper_id),
2479 writer()->is_overwrite(), writer()->compressor());
2480 if (!segment_writer.has_error()) {
2481 if (is_vm_dumper(dumper_id)) {
2482 // dump some non-heap subrecords to heap dump segment
2483 TraceTime timer("Dump non-objects (part 2)", TRACETIME_LOG(Info, heapdump));
2484 // Writes HPROF_GC_CLASS_DUMP records
2485 ClassDumper class_dumper(&segment_writer);
2486 ClassLoaderDataGraph::classes_do(&class_dumper);
2487
2488 // HPROF_GC_ROOT_THREAD_OBJ + frames + jni locals
2489 dump_threads(&segment_writer);
2490
2491 // HPROF_GC_ROOT_JNI_GLOBAL
2492 JNIGlobalsDumper jni_dumper(&segment_writer);
2493 JNIHandles::oops_do(&jni_dumper);
2494 // technically not jni roots, but global roots
2495 // for things like preallocated throwable backtraces
2496 Universe::vm_global()->oops_do(&jni_dumper);
2497 // HPROF_GC_ROOT_STICKY_CLASS
2498 // These should be classes in the null class loader data, and not all classes
2499 // if !ClassUnloading
2500 StickyClassDumper stiky_class_dumper(&segment_writer);
2501 ClassLoaderData::the_null_class_loader_data()->classes_do(&stiky_class_dumper);
2502 }
2503
2504 // Heap iteration.
2505 // writes HPROF_GC_INSTANCE_DUMP records.
2506 // After each sub-record is written check_segment_length will be invoked
2507 // to check if the current segment exceeds a threshold. If so, a new
2508 // segment is started.
2509 // The HPROF_GC_CLASS_DUMP and HPROF_GC_INSTANCE_DUMP are the vast bulk
2510 // of the heap dump.
2511
2512 TraceTime timer(is_parallel_dump() ? "Dump heap objects in parallel" : "Dump heap objects", TRACETIME_LOG(Info, heapdump));
2513 HeapObjectDumper obj_dumper(&segment_writer, this);
2514 if (!is_parallel_dump()) {
2515 Universe::heap()->object_iterate(&obj_dumper);
2516 } else {
2517 // == Parallel dump
2518 _poi->object_iterate(&obj_dumper, worker_id);
2519 }
2520
2521 segment_writer.finish_dump_segment();
2522 segment_writer.flush();
2523 }
2524
2525 _dumper_controller->dumper_complete(&segment_writer, writer());
2526
2527 if (is_vm_dumper(dumper_id)) {
2528 _dumper_controller->wait_all_dumpers_complete();
2529
2530 // flush global writer
2531 writer()->flush();
2532
2533 // At this point, all fragments of the heapdump have been written to separate files.
2534 // We need to merge them into a complete heapdump and write HPROF_HEAP_DUMP_END at that time.
2535 }
2536 }
2537
2538 void VM_HeapDumper::dump_stack_traces(AbstractDumpWriter* writer) {
2539 // write a HPROF_TRACE record without any frames to be referenced as object alloc sites
2540 DumperSupport::write_header(writer, HPROF_TRACE, 3 * sizeof(u4));
2541 writer->write_u4((u4)STACK_TRACE_ID);
2542 writer->write_u4(0); // thread number
2543 writer->write_u4(0); // frame count
2544
2545 // max number if every platform thread is carrier with mounted virtual thread
2546 _thread_dumpers = NEW_C_HEAP_ARRAY(ThreadDumper*, Threads::number_of_threads() * 2, mtInternal);
2547
2548 for (JavaThreadIteratorWithHandle jtiwh; JavaThread * thread = jtiwh.next(); ) {
2549 if (ThreadDumper::should_dump_pthread(thread)) {
2550 bool add_oom_frame = is_oom_thread(thread);
2551
2552 oop mounted_vt = thread->is_vthread_mounted() ? thread->vthread() : nullptr;
2553 if (mounted_vt != nullptr && !ThreadDumper::should_dump_vthread(mounted_vt)) {
2554 mounted_vt = nullptr;
2555 }
2556
2557 // mounted vthread (if any)
2558 if (mounted_vt != nullptr) {
2559 ThreadDumper* thread_dumper = new ThreadDumper(ThreadDumper::ThreadType::MountedVirtual, thread, mounted_vt);
2560 _thread_dumpers[_thread_dumpers_count++] = thread_dumper;
2561 if (add_oom_frame) {
2562 thread_dumper->add_oom_frame(_oome_constructor);
2563 // we add oom frame to the VT stack, don't add it to the carrier thread stack
2564 add_oom_frame = false;
2565 }
2566 thread_dumper->init_serial_nums(&_thread_serial_num, &_frame_serial_num);
2567 thread_dumper->dump_stack_traces(writer, _klass_map);
2568 }
2569
2570 // platform or carrier thread
2571 ThreadDumper* thread_dumper = new ThreadDumper(ThreadDumper::ThreadType::Platform, thread, thread->threadObj());
2572 _thread_dumpers[_thread_dumpers_count++] = thread_dumper;
2573 if (add_oom_frame) {
2574 thread_dumper->add_oom_frame(_oome_constructor);
2575 }
2576 thread_dumper->init_serial_nums(&_thread_serial_num, &_frame_serial_num);
2577 thread_dumper->dump_stack_traces(writer, _klass_map);
2578 }
2579 }
2580 }
2581
2582 void VM_HeapDumper::dump_vthread(oop vt, AbstractDumpWriter* segment_writer) {
2583 // unmounted vthread has no JavaThread
2584 ThreadDumper thread_dumper(ThreadDumper::ThreadType::UnmountedVirtual, nullptr, vt);
2585 thread_dumper.init_serial_nums(&_thread_serial_num, &_frame_serial_num);
2586
2587 // write HPROF_TRACE/HPROF_FRAME records to global writer
2588 _dumper_controller->lock_global_writer();
2589 thread_dumper.dump_stack_traces(writer(), _klass_map);
2590 _dumper_controller->unlock_global_writer();
2591
2592 // write HPROF_GC_ROOT_THREAD_OBJ/HPROF_GC_ROOT_JAVA_FRAME/HPROF_GC_ROOT_JNI_LOCAL subrecord
2593 // to segment writer
2594 thread_dumper.dump_thread_obj(segment_writer);
2595 thread_dumper.dump_stack_refs(segment_writer);
2596 }
2597
2598 // dump the heap to given path.
2599 int HeapDumper::dump(const char* path, outputStream* out, int compression, bool overwrite, uint num_dump_threads) {
2600 assert(path != nullptr && strlen(path) > 0, "path missing");
2601
2602 // print message in interactive case
2603 if (out != nullptr) {
2604 out->print_cr("Dumping heap to %s ...", path);
2605 timer()->start();
2606 }
2607
2608 if (_oome && num_dump_threads > 1) {
2609 // Each additional parallel writer requires several MB of internal memory
2610 // (DumpWriter buffer, DumperClassCacheTable, GZipCompressor buffers).
2611 // For the OOM handling we may already be limited in memory.
2612 // Lets ensure we have at least 20MB per thread.
2613 size_t free_memory = 0;
2614 // Return value ignored - defaulting to 0 on failure.
2615 (void)os::free_memory(free_memory);
2616 julong max_threads = free_memory / (20 * M);
2617 if (num_dump_threads > max_threads) {
2618 num_dump_threads = MAX2<uint>(1, (uint)max_threads);
2619 }
2620 }
2621
2622 // create JFR event
2623 EventHeapDump event;
2624
2625 AbstractCompressor* compressor = nullptr;
2626
2627 if (compression > 0) {
2628 compressor = new (std::nothrow) GZipCompressor(compression);
2629
2630 if (compressor == nullptr) {
2631 set_error("Could not allocate gzip compressor");
2632 return -1;
2633 }
2634 }
2635
2636 DumpWriter writer(path, overwrite, compressor);
2637
2638 if (writer.error() != nullptr) {
2639 set_error(writer.error());
2640 if (out != nullptr) {
2641 out->print_cr("Unable to create %s: %s", path,
2642 (error() != nullptr) ? error() : "reason unknown");
2643 }
2644 return -1;
2645 }
2646
2647 // generate the segmented heap dump into separate files
2648 VM_HeapDumper dumper(&writer, _gc_before_heap_dump, _oome, num_dump_threads);
2649 VMThread::execute(&dumper);
2650
2651 // record any error that the writer may have encountered
2652 set_error(writer.error());
2653
2654 // Heap dump process is done in two phases
2655 //
2656 // Phase 1: Concurrent threads directly write heap data to multiple heap files.
2657 // This is done by VM_HeapDumper, which is performed within safepoint.
2658 //
2659 // Phase 2: Merge multiple heap files into one complete heap dump file.
2660 // This is done by DumpMerger, which is performed outside safepoint
2661
2662 DumpMerger merger(path, &writer, dumper.dump_seq());
2663 // Perform heapdump file merge operation in the current thread prevents us
2664 // from occupying the VM Thread, which in turn affects the occurrence of
2665 // GC and other VM operations.
2666 merger.do_merge();
2667 if (writer.error() != nullptr) {
2668 set_error(writer.error());
2669 }
2670
2671 // emit JFR event
2672 if (error() == nullptr) {
2673 event.set_destination(path);
2674 event.set_gcBeforeDump(_gc_before_heap_dump);
2675 event.set_size(writer.bytes_written());
2676 event.set_onOutOfMemoryError(_oome);
2677 event.set_overwrite(overwrite);
2678 event.set_compression(compression);
2679 event.commit();
2680 } else {
2681 log_debug(aot, heap)("Error %s while dumping heap", error());
2682 }
2683
2684 // print message in interactive case
2685 if (out != nullptr) {
2686 timer()->stop();
2687 if (error() == nullptr) {
2688 out->print_cr("Heap dump file created [" JULONG_FORMAT " bytes in %3.3f secs]",
2689 writer.bytes_written(), timer()->seconds());
2690 } else {
2691 out->print_cr("Dump file is incomplete: %s", writer.error());
2692 }
2693 }
2694
2695 if (compressor != nullptr) {
2696 delete compressor;
2697 }
2698 return (writer.error() == nullptr) ? 0 : -1;
2699 }
2700
2701 // stop timer (if still active), and free any error string we might be holding
2702 HeapDumper::~HeapDumper() {
2703 if (timer()->is_active()) {
2704 timer()->stop();
2705 }
2706 set_error(nullptr);
2707 }
2708
2709
2710 // returns the error string (resource allocated), or null
2711 char* HeapDumper::error_as_C_string() const {
2712 if (error() != nullptr) {
2713 char* str = ResourceArea::strdup(error());
2714 return str;
2715 } else {
2716 return nullptr;
2717 }
2718 }
2719
2720 // set the error string
2721 void HeapDumper::set_error(char const* error) {
2722 if (_error != nullptr) {
2723 os::free(_error);
2724 }
2725 if (error == nullptr) {
2726 _error = nullptr;
2727 } else {
2728 _error = os::strdup(error);
2729 assert(_error != nullptr, "allocation failure");
2730 }
2731 }
2732
2733 // Called by out-of-memory error reporting by a single Java thread
2734 // outside of a JVM safepoint
2735 void HeapDumper::dump_heap_from_oome() {
2736 HeapDumper::dump_heap(true);
2737 }
2738
2739 // Called by error reporting by a single Java thread outside of a JVM safepoint,
2740 // or by heap dumping by the VM thread during a (GC) safepoint. Thus, these various
2741 // callers are strictly serialized and guaranteed not to interfere below. For more
2742 // general use, however, this method will need modification to prevent
2743 // inteference when updating the static variables base_path and dump_file_seq below.
2744 void HeapDumper::dump_heap() {
2745 HeapDumper::dump_heap(false);
2746 }
2747
2748 void HeapDumper::dump_heap(bool oome) {
2749 static char base_path[JVM_MAXPATHLEN] = {'\0'};
2750 static uint dump_file_seq = 0;
2751 char my_path[JVM_MAXPATHLEN];
2752 const int max_digit_chars = 20;
2753 const char* dump_file_name = HeapDumpGzipLevel > 0 ? "java_pid%p.hprof.gz" : "java_pid%p.hprof";
2754
2755 // The dump file defaults to java_pid<pid>.hprof in the current working
2756 // directory. HeapDumpPath=<file> can be used to specify an alternative
2757 // dump file name or a directory where dump file is created.
2758 if (dump_file_seq == 0) { // first time in, we initialize base_path
2759 // Set base path (name or directory, default or custom, without seq no), doing %p substitution.
2760 const char *path_src = (HeapDumpPath != nullptr && HeapDumpPath[0] != '\0') ? HeapDumpPath : dump_file_name;
2761 if (!Arguments::copy_expand_pid(path_src, strlen(path_src), base_path, JVM_MAXPATHLEN - max_digit_chars)) {
2762 warning("Cannot create heap dump file. HeapDumpPath is too long.");
2763 return;
2764 }
2765 // Check if the path is an existing directory
2766 DIR* dir = os::opendir(base_path);
2767 if (dir != nullptr) {
2768 os::closedir(dir);
2769 // Path is a directory. Append a file separator (if needed).
2770 size_t fs_len = strlen(os::file_separator());
2771 if (strlen(base_path) >= fs_len) {
2772 char* end = base_path;
2773 end += (strlen(base_path) - fs_len);
2774 if (strcmp(end, os::file_separator()) != 0) {
2775 strcat(base_path, os::file_separator());
2776 }
2777 }
2778 // Then add the default name, with %p substitution. Use my_path temporarily.
2779 if (!Arguments::copy_expand_pid(dump_file_name, strlen(dump_file_name), my_path, JVM_MAXPATHLEN - max_digit_chars)) {
2780 warning("Cannot create heap dump file. HeapDumpPath is too long.");
2781 return;
2782 }
2783 const size_t dlen = strlen(base_path);
2784 jio_snprintf(&base_path[dlen], sizeof(base_path) - dlen, "%s", my_path);
2785 }
2786 strncpy(my_path, base_path, JVM_MAXPATHLEN);
2787 } else {
2788 // Append a sequence number id for dumps following the first
2789 const size_t len = strlen(base_path) + max_digit_chars + 2; // for '.' and \0
2790 jio_snprintf(my_path, len, "%s.%d", base_path, dump_file_seq);
2791 }
2792 dump_file_seq++; // increment seq number for next time we dump
2793
2794 HeapDumper dumper(false /* no GC before heap dump */,
2795 oome /* pass along out-of-memory-error flag */);
2796 dumper.dump(my_path, tty, HeapDumpGzipLevel);
2797 }