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/continuationWrapper.inline.hpp"
47 #include "runtime/frame.inline.hpp"
48 #include "runtime/handles.inline.hpp"
49 #include "runtime/javaCalls.hpp"
50 #include "runtime/javaThread.inline.hpp"
51 #include "runtime/jniHandles.hpp"
52 #include "runtime/os.hpp"
53 #include "runtime/threads.hpp"
54 #include "runtime/threadSMR.hpp"
55 #include "runtime/vframe.hpp"
56 #include "runtime/vmOperations.hpp"
57 #include "runtime/vmThread.hpp"
58 #include "runtime/timerTrace.hpp"
59 #include "services/heapDumper.hpp"
60 #include "services/heapDumperCompression.hpp"
61 #include "services/threadService.hpp"
62 #include "utilities/checkedCast.hpp"
63 #include "utilities/macros.hpp"
64 #include "utilities/ostream.hpp"
65 #ifdef LINUX
66 #include "os_linux.hpp"
67 #endif
68
69 /*
70 * HPROF binary format - description copied from:
71 * src/share/demo/jvmti/hprof/hprof_io.c
72 *
73 *
74 * header "JAVA PROFILE 1.0.2" (0-terminated)
75 *
76 * u4 size of identifiers. Identifiers are used to represent
77 * UTF8 strings, objects, stack traces, etc. They usually
78 * have the same size as host pointers.
79 * u4 high word
80 * u4 low word number of milliseconds since 0:00 GMT, 1/1/70
81 * [record]* a sequence of records.
82 *
83 *
84 * Record format:
85 *
86 * u1 a TAG denoting the type of the record
87 * u4 number of *microseconds* since the time stamp in the
88 * header. (wraps around in a little more than an hour)
89 * u4 number of bytes *remaining* in the record. Note that
90 * this number excludes the tag and the length field itself.
91 * [u1]* BODY of the record (a sequence of bytes)
92 *
93 *
94 * The following TAGs are supported:
95 *
96 * TAG BODY notes
97 *----------------------------------------------------------
98 * HPROF_UTF8 a UTF8-encoded name
99 *
100 * id name ID
101 * [u1]* UTF8 characters (no trailing zero)
102 *
103 * HPROF_LOAD_CLASS a newly loaded class
104 *
105 * u4 class serial number (> 0)
106 * id class object ID
107 * u4 stack trace serial number
108 * id class name ID
109 *
110 * HPROF_UNLOAD_CLASS an unloading class
111 *
112 * u4 class serial_number
113 *
114 * HPROF_FRAME a Java stack frame
115 *
116 * id stack frame ID
117 * id method name ID
118 * id method signature ID
119 * id source file name ID
120 * u4 class serial number
121 * i4 line number. >0: normal
122 * -1: unknown
123 * -2: compiled method
124 * -3: native method
125 *
126 * HPROF_TRACE a Java stack trace
127 *
128 * u4 stack trace serial number
129 * u4 thread serial number
130 * u4 number of frames
131 * [id]* stack frame IDs
132 *
133 *
134 * HPROF_ALLOC_SITES a set of heap allocation sites, obtained after GC
135 *
136 * u2 flags 0x0001: incremental vs. complete
137 * 0x0002: sorted by allocation vs. live
138 * 0x0004: whether to force a GC
139 * u4 cutoff ratio
140 * u4 total live bytes
141 * u4 total live instances
142 * u8 total bytes allocated
143 * u8 total instances allocated
144 * u4 number of sites that follow
145 * [u1 is_array: 0: normal object
146 * 2: object array
147 * 4: boolean array
148 * 5: char array
149 * 6: float array
150 * 7: double array
151 * 8: byte array
152 * 9: short array
153 * 10: int array
154 * 11: long array
155 * u4 class serial number (may be zero during startup)
156 * u4 stack trace serial number
157 * u4 number of bytes alive
158 * u4 number of instances alive
159 * u4 number of bytes allocated
160 * u4]* number of instance allocated
161 *
162 * HPROF_START_THREAD a newly started thread.
163 *
164 * u4 thread serial number (> 0)
165 * id thread object ID
166 * u4 stack trace serial number
167 * id thread name ID
168 * id thread group name ID
169 * id thread group parent name ID
170 *
171 * HPROF_END_THREAD a terminating thread.
172 *
173 * u4 thread serial number
174 *
175 * HPROF_HEAP_SUMMARY heap summary
176 *
177 * u4 total live bytes
178 * u4 total live instances
179 * u8 total bytes allocated
180 * u8 total instances allocated
181 *
182 * HPROF_HEAP_DUMP denote a heap dump
183 *
184 * [heap dump sub-records]*
185 *
186 * There are four kinds of heap dump sub-records:
187 *
188 * u1 sub-record type
189 *
190 * HPROF_GC_ROOT_UNKNOWN unknown root
191 *
192 * id object ID
193 *
194 * HPROF_GC_ROOT_THREAD_OBJ thread object
195 *
196 * id thread object ID (may be 0 for a
197 * thread newly attached through JNI)
198 * u4 thread sequence number
199 * u4 stack trace sequence number
200 *
201 * HPROF_GC_ROOT_JNI_GLOBAL JNI global ref root
202 *
203 * id object ID
204 * id JNI global ref ID
205 *
206 * HPROF_GC_ROOT_JNI_LOCAL JNI local ref
207 *
208 * id object ID
209 * u4 thread serial number
210 * u4 frame # in stack trace (-1 for empty)
211 *
212 * HPROF_GC_ROOT_JAVA_FRAME Java stack frame
213 *
214 * id object ID
215 * u4 thread serial number
216 * u4 frame # in stack trace (-1 for empty)
217 *
218 * HPROF_GC_ROOT_NATIVE_STACK Native stack
219 *
220 * id object ID
221 * u4 thread serial number
222 *
223 * HPROF_GC_ROOT_STICKY_CLASS System class
224 *
225 * id object ID
226 *
227 * HPROF_GC_ROOT_THREAD_BLOCK Reference from thread block
228 *
229 * id object ID
230 * u4 thread serial number
231 *
232 * HPROF_GC_ROOT_MONITOR_USED Busy monitor
233 *
234 * id object ID
235 *
236 * HPROF_GC_CLASS_DUMP dump of a class object
237 *
238 * id class object ID
239 * u4 stack trace serial number
240 * id super class object ID
241 * id class loader object ID
242 * id signers object ID
243 * id protection domain object ID
244 * id reserved
245 * id reserved
246 *
247 * u4 instance size (in bytes)
248 *
249 * u2 size of constant pool
250 * [u2, constant pool index,
251 * ty, type
252 * 2: object
253 * 4: boolean
254 * 5: char
255 * 6: float
256 * 7: double
257 * 8: byte
258 * 9: short
259 * 10: int
260 * 11: long
261 * vl]* and value
262 *
263 * u2 number of static fields
264 * [id, static field name,
265 * ty, type,
266 * vl]* and value
267 *
268 * u2 number of inst. fields (not inc. super)
269 * [id, instance field name,
270 * ty]* type
271 *
272 * HPROF_GC_INSTANCE_DUMP dump of a normal object
273 *
274 * id object ID
275 * u4 stack trace serial number
276 * id class object ID
277 * u4 number of bytes that follow
278 * [vl]* instance field values (class, followed
279 * by super, super's super ...)
280 *
281 * HPROF_GC_OBJ_ARRAY_DUMP dump of an object array
282 *
283 * id array object ID
284 * u4 stack trace serial number
285 * u4 number of elements
286 * id array class ID
287 * [id]* elements
288 *
289 * HPROF_GC_PRIM_ARRAY_DUMP dump of a primitive array
290 *
291 * id array object ID
292 * u4 stack trace serial number
293 * u4 number of elements
294 * u1 element type
295 * 4: boolean array
296 * 5: char array
297 * 6: float array
298 * 7: double array
299 * 8: byte array
300 * 9: short array
301 * 10: int array
302 * 11: long array
303 * [u1]* elements
304 *
305 * HPROF_CPU_SAMPLES a set of sample traces of running threads
306 *
307 * u4 total number of samples
308 * u4 # of traces
309 * [u4 # of samples
310 * u4]* stack trace serial number
311 *
312 * HPROF_CONTROL_SETTINGS the settings of on/off switches
313 *
314 * u4 0x00000001: alloc traces on/off
315 * 0x00000002: cpu sampling on/off
316 * u2 stack trace depth
317 *
318 *
319 * When the header is "JAVA PROFILE 1.0.2" a heap dump can optionally
320 * be generated as a sequence of heap dump segments. This sequence is
321 * terminated by an end record. The additional tags allowed by format
322 * "JAVA PROFILE 1.0.2" are:
323 *
324 * HPROF_HEAP_DUMP_SEGMENT denote a heap dump segment
325 *
326 * [heap dump sub-records]*
327 * The same sub-record types allowed by HPROF_HEAP_DUMP
328 *
329 * HPROF_HEAP_DUMP_END denotes the end of a heap dump
330 *
331 */
332
333
334 // HPROF tags
335
336 enum hprofTag : u1 {
337 // top-level records
338 HPROF_UTF8 = 0x01,
339 HPROF_LOAD_CLASS = 0x02,
340 HPROF_UNLOAD_CLASS = 0x03,
341 HPROF_FRAME = 0x04,
342 HPROF_TRACE = 0x05,
343 HPROF_ALLOC_SITES = 0x06,
344 HPROF_HEAP_SUMMARY = 0x07,
345 HPROF_START_THREAD = 0x0A,
346 HPROF_END_THREAD = 0x0B,
347 HPROF_HEAP_DUMP = 0x0C,
348 HPROF_CPU_SAMPLES = 0x0D,
349 HPROF_CONTROL_SETTINGS = 0x0E,
350
351 // 1.0.2 record types
352 HPROF_HEAP_DUMP_SEGMENT = 0x1C,
353 HPROF_HEAP_DUMP_END = 0x2C,
354
355 // field types
356 HPROF_ARRAY_OBJECT = 0x01,
357 HPROF_NORMAL_OBJECT = 0x02,
358 HPROF_BOOLEAN = 0x04,
359 HPROF_CHAR = 0x05,
360 HPROF_FLOAT = 0x06,
361 HPROF_DOUBLE = 0x07,
362 HPROF_BYTE = 0x08,
363 HPROF_SHORT = 0x09,
364 HPROF_INT = 0x0A,
365 HPROF_LONG = 0x0B,
366
367 // data-dump sub-records
368 HPROF_GC_ROOT_UNKNOWN = 0xFF,
369 HPROF_GC_ROOT_JNI_GLOBAL = 0x01,
370 HPROF_GC_ROOT_JNI_LOCAL = 0x02,
371 HPROF_GC_ROOT_JAVA_FRAME = 0x03,
372 HPROF_GC_ROOT_NATIVE_STACK = 0x04,
373 HPROF_GC_ROOT_STICKY_CLASS = 0x05,
374 HPROF_GC_ROOT_THREAD_BLOCK = 0x06,
375 HPROF_GC_ROOT_MONITOR_USED = 0x07,
376 HPROF_GC_ROOT_THREAD_OBJ = 0x08,
377 HPROF_GC_CLASS_DUMP = 0x20,
378 HPROF_GC_INSTANCE_DUMP = 0x21,
379 HPROF_GC_OBJ_ARRAY_DUMP = 0x22,
380 HPROF_GC_PRIM_ARRAY_DUMP = 0x23
381 };
382
383 // Default stack trace ID (used for dummy HPROF_TRACE record)
384 enum {
385 STACK_TRACE_ID = 1,
386 INITIAL_CLASS_COUNT = 200
387 };
388
389 // Supports I/O operations for a dump
390 // Base class for dump and parallel dump
391 class AbstractDumpWriter : public CHeapObj<mtInternal> {
392 protected:
393 enum {
394 io_buffer_max_size = 1*M,
395 dump_segment_header_size = 9
396 };
397
398 char* _buffer; // internal buffer
399 size_t _size;
400 size_t _pos;
401
402 bool _in_dump_segment; // Are we currently in a dump segment?
403 bool _is_huge_sub_record; // Are we writing a sub-record larger than the buffer size?
404 DEBUG_ONLY(size_t _sub_record_left;) // The bytes not written for the current sub-record.
405 DEBUG_ONLY(bool _sub_record_ended;) // True if we have called the end_sub_record().
406
407 char* buffer() const { return _buffer; }
408 size_t buffer_size() const { return _size; }
409 void set_position(size_t pos) { _pos = pos; }
410
411 // Can be called if we have enough room in the buffer.
412 void write_fast(const void* s, size_t len);
413
414 // Returns true if we have enough room in the buffer for 'len' bytes.
415 bool can_write_fast(size_t len);
416
417 void write_address(address a);
418
419 public:
420 AbstractDumpWriter() :
421 _buffer(nullptr),
422 _size(io_buffer_max_size),
423 _pos(0),
424 _in_dump_segment(false) { }
425
426 // Total number of bytes written to the disk
427 virtual julong bytes_written() const = 0;
428 // Return non-null if error occurred
429 virtual char const* error() const = 0;
430
431 size_t position() const { return _pos; }
432 // writer functions
433 virtual void write_raw(const void* s, size_t len);
434 void write_u1(u1 x);
435 void write_u2(u2 x);
436 void write_u4(u4 x);
437 void write_u8(u8 x);
438 void write_objectID(oop o);
439 void write_rootID(oop* p);
440 void write_symbolID(Symbol* o);
441 void write_classID(Klass* k);
442 void write_id(u4 x);
443
444 // Start a new sub-record. Starts a new heap dump segment if needed.
445 void start_sub_record(u1 tag, u4 len);
446 // Ends the current sub-record.
447 void end_sub_record();
448 // Finishes the current dump segment if not already finished.
449 void finish_dump_segment();
450 // Flush internal buffer to persistent storage
451 virtual void flush() = 0;
452 };
453
454 void AbstractDumpWriter::write_fast(const void* s, size_t len) {
455 assert(!_in_dump_segment || (_sub_record_left >= len), "sub-record too large");
456 assert(buffer_size() - position() >= len, "Must fit");
457 debug_only(_sub_record_left -= len);
458 memcpy(buffer() + position(), s, len);
459 set_position(position() + len);
460 }
461
462 bool AbstractDumpWriter::can_write_fast(size_t len) {
463 return buffer_size() - position() >= len;
464 }
465
466 // write raw bytes
467 void AbstractDumpWriter::write_raw(const void* s, size_t len) {
468 assert(!_in_dump_segment || (_sub_record_left >= len), "sub-record too large");
469 debug_only(_sub_record_left -= len);
470
471 // flush buffer to make room.
472 while (len > buffer_size() - position()) {
473 assert(!_in_dump_segment || _is_huge_sub_record,
474 "Cannot overflow in non-huge sub-record.");
475 size_t to_write = buffer_size() - position();
476 memcpy(buffer() + position(), s, to_write);
477 s = (void*) ((char*) s + to_write);
478 len -= to_write;
479 set_position(position() + to_write);
480 flush();
481 }
482
483 memcpy(buffer() + position(), s, len);
484 set_position(position() + len);
485 }
486
487 // Makes sure we inline the fast write into the write_u* functions. This is a big speedup.
488 #define WRITE_KNOWN_TYPE(p, len) do { if (can_write_fast((len))) write_fast((p), (len)); \
489 else write_raw((p), (len)); } while (0)
490
491 void AbstractDumpWriter::write_u1(u1 x) {
492 WRITE_KNOWN_TYPE(&x, 1);
493 }
494
495 void AbstractDumpWriter::write_u2(u2 x) {
496 u2 v;
497 Bytes::put_Java_u2((address)&v, x);
498 WRITE_KNOWN_TYPE(&v, 2);
499 }
500
501 void AbstractDumpWriter::write_u4(u4 x) {
502 u4 v;
503 Bytes::put_Java_u4((address)&v, x);
504 WRITE_KNOWN_TYPE(&v, 4);
505 }
506
507 void AbstractDumpWriter::write_u8(u8 x) {
508 u8 v;
509 Bytes::put_Java_u8((address)&v, x);
510 WRITE_KNOWN_TYPE(&v, 8);
511 }
512
513 void AbstractDumpWriter::write_address(address a) {
514 #ifdef _LP64
515 write_u8((u8)a);
516 #else
517 write_u4((u4)a);
518 #endif
519 }
520
521 void AbstractDumpWriter::write_objectID(oop o) {
522 write_address(cast_from_oop<address>(o));
523 }
524
525 void AbstractDumpWriter::write_rootID(oop* p) {
526 write_address((address)p);
527 }
528
529 void AbstractDumpWriter::write_symbolID(Symbol* s) {
530 write_address((address)((uintptr_t)s));
531 }
532
533 void AbstractDumpWriter::write_id(u4 x) {
534 #ifdef _LP64
535 write_u8((u8) x);
536 #else
537 write_u4(x);
538 #endif
539 }
540
541 // We use java mirror as the class ID
542 void AbstractDumpWriter::write_classID(Klass* k) {
543 write_objectID(k->java_mirror());
544 }
545
546 void AbstractDumpWriter::finish_dump_segment() {
547 if (_in_dump_segment) {
548 assert(_sub_record_left == 0, "Last sub-record not written completely");
549 assert(_sub_record_ended, "sub-record must have ended");
550
551 // Fix up the dump segment length if we haven't written a huge sub-record last
552 // (in which case the segment length was already set to the correct value initially).
553 if (!_is_huge_sub_record) {
554 assert(position() > dump_segment_header_size, "Dump segment should have some content");
555 Bytes::put_Java_u4((address) (buffer() + 5),
556 (u4) (position() - dump_segment_header_size));
557 } else {
558 // Finish process huge sub record
559 // Set _is_huge_sub_record to false so the parallel dump writer can flush data to file.
560 _is_huge_sub_record = false;
561 }
562
563 _in_dump_segment = false;
564 flush();
565 }
566 }
567
568 void AbstractDumpWriter::start_sub_record(u1 tag, u4 len) {
569 if (!_in_dump_segment) {
570 if (position() > 0) {
571 flush();
572 }
573
574 assert(position() == 0 && buffer_size() > dump_segment_header_size, "Must be at the start");
575
576 write_u1(HPROF_HEAP_DUMP_SEGMENT);
577 write_u4(0); // timestamp
578 // Will be fixed up later if we add more sub-records. If this is a huge sub-record,
579 // this is already the correct length, since we don't add more sub-records.
580 write_u4(len);
581 assert(Bytes::get_Java_u4((address)(buffer() + 5)) == len, "Inconsistent size!");
582 _in_dump_segment = true;
583 _is_huge_sub_record = len > buffer_size() - dump_segment_header_size;
584 } else if (_is_huge_sub_record || (len > buffer_size() - position())) {
585 // This object will not fit in completely or the last sub-record was huge.
586 // Finish the current segment and try again.
587 finish_dump_segment();
588 start_sub_record(tag, len);
589
590 return;
591 }
592
593 debug_only(_sub_record_left = len);
594 debug_only(_sub_record_ended = false);
595
596 write_u1(tag);
597 }
598
599 void AbstractDumpWriter::end_sub_record() {
600 assert(_in_dump_segment, "must be in dump segment");
601 assert(_sub_record_left == 0, "sub-record not written completely");
602 assert(!_sub_record_ended, "Must not have ended yet");
603 debug_only(_sub_record_ended = true);
604 }
605
606 // Supports I/O operations for a dump
607
608 class DumpWriter : public AbstractDumpWriter {
609 private:
610 FileWriter* _writer;
611 AbstractCompressor* _compressor;
612 size_t _bytes_written;
613 char* _error;
614 // Compression support
615 char* _out_buffer;
616 size_t _out_size;
617 size_t _out_pos;
618 char* _tmp_buffer;
619 size_t _tmp_size;
620
621 private:
622 void do_compress();
623
624 public:
625 DumpWriter(const char* path, bool overwrite, AbstractCompressor* compressor);
626 ~DumpWriter();
627 julong bytes_written() const override { return (julong) _bytes_written; }
628 char const* error() const override { return _error; }
629 void set_error(const char* error) { _error = (char*)error; }
630 bool has_error() const { return _error != nullptr; }
631 const char* get_file_path() const { return _writer->get_file_path(); }
632 AbstractCompressor* compressor() { return _compressor; }
633 bool is_overwrite() const { return _writer->is_overwrite(); }
634
635 void flush() override;
636
637 private:
638 // internals for DumpMerger
639 friend class DumpMerger;
640 void set_bytes_written(julong bytes_written) { _bytes_written = bytes_written; }
641 int get_fd() const { return _writer->get_fd(); }
642 void set_compressor(AbstractCompressor* p) { _compressor = p; }
643 };
644
645 DumpWriter::DumpWriter(const char* path, bool overwrite, AbstractCompressor* compressor) :
646 AbstractDumpWriter(),
647 _writer(new (std::nothrow) FileWriter(path, overwrite)),
648 _compressor(compressor),
649 _bytes_written(0),
650 _error(nullptr),
651 _out_buffer(nullptr),
652 _out_size(0),
653 _out_pos(0),
654 _tmp_buffer(nullptr),
655 _tmp_size(0) {
656 _error = (char*)_writer->open_writer();
657 if (_error == nullptr) {
658 _buffer = (char*)os::malloc(io_buffer_max_size, mtInternal);
659 if (compressor != nullptr) {
660 _error = (char*)_compressor->init(io_buffer_max_size, &_out_size, &_tmp_size);
661 if (_error == nullptr) {
662 if (_out_size > 0) {
663 _out_buffer = (char*)os::malloc(_out_size, mtInternal);
664 }
665 if (_tmp_size > 0) {
666 _tmp_buffer = (char*)os::malloc(_tmp_size, mtInternal);
667 }
668 }
669 }
670 }
671 // initialize internal buffer
672 _pos = 0;
673 _size = io_buffer_max_size;
674 }
675
676 DumpWriter::~DumpWriter(){
677 if (_buffer != nullptr) {
678 os::free(_buffer);
679 }
680 if (_out_buffer != nullptr) {
681 os::free(_out_buffer);
682 }
683 if (_tmp_buffer != nullptr) {
684 os::free(_tmp_buffer);
685 }
686 if (_writer != nullptr) {
687 delete _writer;
688 }
689 _bytes_written = -1;
690 }
691
692 // flush any buffered bytes to the file
693 void DumpWriter::flush() {
694 if (_pos <= 0) {
695 return;
696 }
697 if (has_error()) {
698 _pos = 0;
699 return;
700 }
701 char* result = nullptr;
702 if (_compressor == nullptr) {
703 result = (char*)_writer->write_buf(_buffer, _pos);
704 _bytes_written += _pos;
705 } else {
706 do_compress();
707 if (!has_error()) {
708 result = (char*)_writer->write_buf(_out_buffer, _out_pos);
709 _bytes_written += _out_pos;
710 }
711 }
712 _pos = 0; // reset pos to make internal buffer available
713
714 if (result != nullptr) {
715 set_error(result);
716 }
717 }
718
719 void DumpWriter::do_compress() {
720 const char* msg = _compressor->compress(_buffer, _pos, _out_buffer, _out_size,
721 _tmp_buffer, _tmp_size, &_out_pos);
722
723 if (msg != nullptr) {
724 set_error(msg);
725 }
726 }
727
728 class DumperClassCacheTable;
729 class DumperClassCacheTableEntry;
730
731 // Support class with a collection of functions used when dumping the heap
732 class DumperSupport : AllStatic {
733 public:
734
735 // write a header of the given type
736 static void write_header(AbstractDumpWriter* writer, hprofTag tag, u4 len);
737
738 // returns hprof tag for the given type signature
739 static hprofTag sig2tag(Symbol* sig);
740 // returns hprof tag for the given basic type
741 static hprofTag type2tag(BasicType type);
742 // Returns the size of the data to write.
743 static u4 sig2size(Symbol* sig);
744
745 // returns the size of the instance of the given class
746 static u4 instance_size(InstanceKlass* ik, DumperClassCacheTableEntry* class_cache_entry = nullptr);
747
748 // dump a jfloat
749 static void dump_float(AbstractDumpWriter* writer, jfloat f);
750 // dump a jdouble
751 static void dump_double(AbstractDumpWriter* writer, jdouble d);
752 // dumps the raw value of the given field
753 static void dump_field_value(AbstractDumpWriter* writer, char type, oop obj, int offset);
754 // returns the size of the static fields; also counts the static fields
755 static u4 get_static_fields_size(InstanceKlass* ik, u2& field_count);
756 // dumps static fields of the given class
757 static void dump_static_fields(AbstractDumpWriter* writer, Klass* k);
758 // dump the raw values of the instance fields of the given object
759 static void dump_instance_fields(AbstractDumpWriter* writer, oop o, DumperClassCacheTableEntry* class_cache_entry);
760 // get the count of the instance fields for a given class
761 static u2 get_instance_fields_count(InstanceKlass* ik);
762 // dumps the definition of the instance fields for a given class
763 static void dump_instance_field_descriptors(AbstractDumpWriter* writer, Klass* k);
764 // creates HPROF_GC_INSTANCE_DUMP record for the given object
765 static void dump_instance(AbstractDumpWriter* writer, oop o, DumperClassCacheTable* class_cache);
766 // creates HPROF_GC_CLASS_DUMP record for the given instance class
767 static void dump_instance_class(AbstractDumpWriter* writer, Klass* k);
768 // creates HPROF_GC_CLASS_DUMP record for a given array class
769 static void dump_array_class(AbstractDumpWriter* writer, Klass* k);
770
771 // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
772 static void dump_object_array(AbstractDumpWriter* writer, objArrayOop array);
773 // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
774 static void dump_prim_array(AbstractDumpWriter* writer, typeArrayOop array);
775 // create HPROF_FRAME record for the given method and bci
776 static void dump_stack_frame(AbstractDumpWriter* writer, int frame_serial_num, int class_serial_num, Method* m, int bci);
777
778 // check if we need to truncate an array
779 static int calculate_array_max_length(AbstractDumpWriter* writer, arrayOop array, short header_size);
780
781 // fixes up the current dump record and writes HPROF_HEAP_DUMP_END record
782 static void end_of_dump(AbstractDumpWriter* writer);
783
784 static oop mask_dormant_archived_object(oop o, oop ref_obj) {
785 if (o != nullptr && o->klass()->java_mirror_no_keepalive() == nullptr) {
786 // Ignore this object since the corresponding java mirror is not loaded.
787 // Might be a dormant archive object.
788 report_dormant_archived_object(o, ref_obj);
789 return nullptr;
790 } else {
791 return o;
792 }
793 }
794
795 static void report_dormant_archived_object(oop o, oop ref_obj) {
796 if (log_is_enabled(Trace, cds, heap)) {
797 ResourceMark rm;
798 if (ref_obj != nullptr) {
799 log_trace(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s) referenced by " INTPTR_FORMAT " (%s)",
800 p2i(o), o->klass()->external_name(),
801 p2i(ref_obj), ref_obj->klass()->external_name());
802 } else {
803 log_trace(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s)",
804 p2i(o), o->klass()->external_name());
805 }
806 }
807 }
808 };
809
810 // Hash table of klasses to the klass metadata. This should greatly improve the
811 // hash dumping performance. This hash table is supposed to be used by a single
812 // thread only.
813 //
814 class DumperClassCacheTableEntry : public CHeapObj<mtServiceability> {
815 friend class DumperClassCacheTable;
816 private:
817 GrowableArray<char> _sigs_start;
818 GrowableArray<int> _offsets;
819 u4 _instance_size;
820 int _entries;
821
822 public:
823 DumperClassCacheTableEntry() : _instance_size(0), _entries(0) {};
824
825 int field_count() { return _entries; }
826 char sig_start(int field_idx) { return _sigs_start.at(field_idx); }
827 int offset(int field_idx) { return _offsets.at(field_idx); }
828 u4 instance_size() { return _instance_size; }
829 };
830
831 class DumperClassCacheTable {
832 private:
833 // ResourceHashtable SIZE is specified at compile time so we
834 // use 1031 which is the first prime after 1024.
835 static constexpr size_t TABLE_SIZE = 1031;
836
837 // Maintain the cache for N classes. This limits memory footprint
838 // impact, regardless of how many classes we have in the dump.
839 // This also improves look up performance by keeping the statically
840 // sized table from overloading.
841 static constexpr int CACHE_TOP = 256;
842
843 typedef ResourceHashtable<InstanceKlass*, DumperClassCacheTableEntry*,
844 TABLE_SIZE, AnyObj::C_HEAP, mtServiceability> PtrTable;
845 PtrTable* _ptrs;
846
847 // Single-slot cache to handle the major case of objects of the same
848 // class back-to-back, e.g. from T[].
849 InstanceKlass* _last_ik;
850 DumperClassCacheTableEntry* _last_entry;
851
852 void unlink_all(PtrTable* table) {
853 class CleanupEntry: StackObj {
854 public:
855 bool do_entry(InstanceKlass*& key, DumperClassCacheTableEntry*& entry) {
856 delete entry;
857 return true;
858 }
859 } cleanup;
860 table->unlink(&cleanup);
861 }
862
863 public:
864 DumperClassCacheTableEntry* lookup_or_create(InstanceKlass* ik) {
865 if (_last_ik == ik) {
866 return _last_entry;
867 }
868
869 DumperClassCacheTableEntry* entry;
870 DumperClassCacheTableEntry** from_cache = _ptrs->get(ik);
871 if (from_cache == nullptr) {
872 entry = new DumperClassCacheTableEntry();
873 for (HierarchicalFieldStream<JavaFieldStream> fld(ik); !fld.done(); fld.next()) {
874 if (!fld.access_flags().is_static()) {
875 Symbol* sig = fld.signature();
876 entry->_sigs_start.push(sig->char_at(0));
877 entry->_offsets.push(fld.offset());
878 entry->_entries++;
879 entry->_instance_size += DumperSupport::sig2size(sig);
880 }
881 }
882
883 if (_ptrs->number_of_entries() >= CACHE_TOP) {
884 // We do not track the individual hit rates for table entries.
885 // Purge the entire table, and let the cache catch up with new
886 // distribution.
887 unlink_all(_ptrs);
888 }
889
890 _ptrs->put(ik, entry);
891 } else {
892 entry = *from_cache;
893 }
894
895 // Remember for single-slot cache.
896 _last_ik = ik;
897 _last_entry = entry;
898
899 return entry;
900 }
901
902 DumperClassCacheTable() : _ptrs(new (mtServiceability) PtrTable), _last_ik(nullptr), _last_entry(nullptr) {}
903
904 ~DumperClassCacheTable() {
905 unlink_all(_ptrs);
906 delete _ptrs;
907 }
908 };
909
910 // write a header of the given type
911 void DumperSupport:: write_header(AbstractDumpWriter* writer, hprofTag tag, u4 len) {
912 writer->write_u1(tag);
913 writer->write_u4(0); // current ticks
914 writer->write_u4(len);
915 }
916
917 // returns hprof tag for the given type signature
918 hprofTag DumperSupport::sig2tag(Symbol* sig) {
919 switch (sig->char_at(0)) {
920 case JVM_SIGNATURE_CLASS : return HPROF_NORMAL_OBJECT;
921 case JVM_SIGNATURE_ARRAY : return HPROF_NORMAL_OBJECT;
922 case JVM_SIGNATURE_BYTE : return HPROF_BYTE;
923 case JVM_SIGNATURE_CHAR : return HPROF_CHAR;
924 case JVM_SIGNATURE_FLOAT : return HPROF_FLOAT;
925 case JVM_SIGNATURE_DOUBLE : return HPROF_DOUBLE;
926 case JVM_SIGNATURE_INT : return HPROF_INT;
927 case JVM_SIGNATURE_LONG : return HPROF_LONG;
928 case JVM_SIGNATURE_SHORT : return HPROF_SHORT;
929 case JVM_SIGNATURE_BOOLEAN : return HPROF_BOOLEAN;
930 default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
931 }
932 }
933
934 hprofTag DumperSupport::type2tag(BasicType type) {
935 switch (type) {
936 case T_BYTE : return HPROF_BYTE;
937 case T_CHAR : return HPROF_CHAR;
938 case T_FLOAT : return HPROF_FLOAT;
939 case T_DOUBLE : return HPROF_DOUBLE;
940 case T_INT : return HPROF_INT;
941 case T_LONG : return HPROF_LONG;
942 case T_SHORT : return HPROF_SHORT;
943 case T_BOOLEAN : return HPROF_BOOLEAN;
944 default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
945 }
946 }
947
948 u4 DumperSupport::sig2size(Symbol* sig) {
949 switch (sig->char_at(0)) {
950 case JVM_SIGNATURE_CLASS:
951 case JVM_SIGNATURE_ARRAY: return sizeof(address);
952 case JVM_SIGNATURE_BOOLEAN:
953 case JVM_SIGNATURE_BYTE: return 1;
954 case JVM_SIGNATURE_SHORT:
955 case JVM_SIGNATURE_CHAR: return 2;
956 case JVM_SIGNATURE_INT:
957 case JVM_SIGNATURE_FLOAT: return 4;
958 case JVM_SIGNATURE_LONG:
959 case JVM_SIGNATURE_DOUBLE: return 8;
960 default: ShouldNotReachHere(); /* to shut up compiler */ return 0;
961 }
962 }
963
964 template<typename T, typename F> T bit_cast(F from) { // replace with the real thing when we can use c++20
965 T to;
966 static_assert(sizeof(to) == sizeof(from), "must be of the same size");
967 memcpy(&to, &from, sizeof(to));
968 return to;
969 }
970
971 // dump a jfloat
972 void DumperSupport::dump_float(AbstractDumpWriter* writer, jfloat f) {
973 if (g_isnan(f)) {
974 writer->write_u4(0x7fc00000); // collapsing NaNs
975 } else {
976 writer->write_u4(bit_cast<u4>(f));
977 }
978 }
979
980 // dump a jdouble
981 void DumperSupport::dump_double(AbstractDumpWriter* writer, jdouble d) {
982 if (g_isnan(d)) {
983 writer->write_u8(0x7ff80000ull << 32); // collapsing NaNs
984 } else {
985 writer->write_u8(bit_cast<u8>(d));
986 }
987 }
988
989 // dumps the raw value of the given field
990 void DumperSupport::dump_field_value(AbstractDumpWriter* writer, char type, oop obj, int offset) {
991 switch (type) {
992 case JVM_SIGNATURE_CLASS :
993 case JVM_SIGNATURE_ARRAY : {
994 oop o = obj->obj_field_access<ON_UNKNOWN_OOP_REF | AS_NO_KEEPALIVE>(offset);
995 o = mask_dormant_archived_object(o, obj);
996 assert(oopDesc::is_oop_or_null(o), "Expected an oop or nullptr at " PTR_FORMAT, p2i(o));
997 writer->write_objectID(o);
998 break;
999 }
1000 case JVM_SIGNATURE_BYTE : {
1001 jbyte b = obj->byte_field(offset);
1002 writer->write_u1(b);
1003 break;
1004 }
1005 case JVM_SIGNATURE_CHAR : {
1006 jchar c = obj->char_field(offset);
1007 writer->write_u2(c);
1008 break;
1009 }
1010 case JVM_SIGNATURE_SHORT : {
1011 jshort s = obj->short_field(offset);
1012 writer->write_u2(s);
1013 break;
1014 }
1015 case JVM_SIGNATURE_FLOAT : {
1016 jfloat f = obj->float_field(offset);
1017 dump_float(writer, f);
1018 break;
1019 }
1020 case JVM_SIGNATURE_DOUBLE : {
1021 jdouble d = obj->double_field(offset);
1022 dump_double(writer, d);
1023 break;
1024 }
1025 case JVM_SIGNATURE_INT : {
1026 jint i = obj->int_field(offset);
1027 writer->write_u4(i);
1028 break;
1029 }
1030 case JVM_SIGNATURE_LONG : {
1031 jlong l = obj->long_field(offset);
1032 writer->write_u8(l);
1033 break;
1034 }
1035 case JVM_SIGNATURE_BOOLEAN : {
1036 jboolean b = obj->bool_field(offset);
1037 writer->write_u1(b);
1038 break;
1039 }
1040 default : {
1041 ShouldNotReachHere();
1042 break;
1043 }
1044 }
1045 }
1046
1047 // returns the size of the instance of the given class
1048 u4 DumperSupport::instance_size(InstanceKlass* ik, DumperClassCacheTableEntry* class_cache_entry) {
1049 if (class_cache_entry != nullptr) {
1050 return class_cache_entry->instance_size();
1051 } else {
1052 u4 size = 0;
1053 for (HierarchicalFieldStream<JavaFieldStream> fld(ik); !fld.done(); fld.next()) {
1054 if (!fld.access_flags().is_static()) {
1055 size += sig2size(fld.signature());
1056 }
1057 }
1058 return size;
1059 }
1060 }
1061
1062 u4 DumperSupport::get_static_fields_size(InstanceKlass* ik, u2& field_count) {
1063 field_count = 0;
1064 u4 size = 0;
1065
1066 for (JavaFieldStream fldc(ik); !fldc.done(); fldc.next()) {
1067 if (fldc.access_flags().is_static()) {
1068 field_count++;
1069 size += sig2size(fldc.signature());
1070 }
1071 }
1072
1073 // Add in resolved_references which is referenced by the cpCache
1074 // The resolved_references is an array per InstanceKlass holding the
1075 // strings and other oops resolved from the constant pool.
1076 oop resolved_references = ik->constants()->resolved_references_or_null();
1077 if (resolved_references != nullptr) {
1078 field_count++;
1079 size += sizeof(address);
1080
1081 // Add in the resolved_references of the used previous versions of the class
1082 // in the case of RedefineClasses
1083 InstanceKlass* prev = ik->previous_versions();
1084 while (prev != nullptr && prev->constants()->resolved_references_or_null() != nullptr) {
1085 field_count++;
1086 size += sizeof(address);
1087 prev = prev->previous_versions();
1088 }
1089 }
1090
1091 // Also provide a pointer to the init_lock if present, so there aren't unreferenced int[0]
1092 // arrays.
1093 oop init_lock = ik->init_lock();
1094 if (init_lock != nullptr) {
1095 field_count++;
1096 size += sizeof(address);
1097 }
1098
1099 // We write the value itself plus a name and a one byte type tag per field.
1100 return checked_cast<u4>(size + field_count * (sizeof(address) + 1));
1101 }
1102
1103 // dumps static fields of the given class
1104 void DumperSupport::dump_static_fields(AbstractDumpWriter* writer, Klass* k) {
1105 InstanceKlass* ik = InstanceKlass::cast(k);
1106
1107 // dump the field descriptors and raw values
1108 for (JavaFieldStream fld(ik); !fld.done(); fld.next()) {
1109 if (fld.access_flags().is_static()) {
1110 Symbol* sig = fld.signature();
1111
1112 writer->write_symbolID(fld.name()); // name
1113 writer->write_u1(sig2tag(sig)); // type
1114
1115 // value
1116 dump_field_value(writer, sig->char_at(0), ik->java_mirror(), fld.offset());
1117 }
1118 }
1119
1120 // Add resolved_references for each class that has them
1121 oop resolved_references = ik->constants()->resolved_references_or_null();
1122 if (resolved_references != nullptr) {
1123 writer->write_symbolID(vmSymbols::resolved_references_name()); // name
1124 writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
1125 writer->write_objectID(resolved_references);
1126
1127 // Also write any previous versions
1128 InstanceKlass* prev = ik->previous_versions();
1129 while (prev != nullptr && prev->constants()->resolved_references_or_null() != nullptr) {
1130 writer->write_symbolID(vmSymbols::resolved_references_name()); // name
1131 writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
1132 writer->write_objectID(prev->constants()->resolved_references());
1133 prev = prev->previous_versions();
1134 }
1135 }
1136
1137 // Add init lock to the end if the class is not yet initialized
1138 oop init_lock = ik->init_lock();
1139 if (init_lock != nullptr) {
1140 writer->write_symbolID(vmSymbols::init_lock_name()); // name
1141 writer->write_u1(sig2tag(vmSymbols::int_array_signature())); // type
1142 writer->write_objectID(init_lock);
1143 }
1144 }
1145
1146 // dump the raw values of the instance fields of the given object
1147 void DumperSupport::dump_instance_fields(AbstractDumpWriter* writer, oop o, DumperClassCacheTableEntry* class_cache_entry) {
1148 assert(class_cache_entry != nullptr, "Pre-condition: must be provided");
1149 for (int idx = 0; idx < class_cache_entry->field_count(); idx++) {
1150 dump_field_value(writer, class_cache_entry->sig_start(idx), o, class_cache_entry->offset(idx));
1151 }
1152 }
1153
1154 // dumps the definition of the instance fields for a given class
1155 u2 DumperSupport::get_instance_fields_count(InstanceKlass* ik) {
1156 u2 field_count = 0;
1157
1158 for (JavaFieldStream fldc(ik); !fldc.done(); fldc.next()) {
1159 if (!fldc.access_flags().is_static()) field_count++;
1160 }
1161
1162 return field_count;
1163 }
1164
1165 // dumps the definition of the instance fields for a given class
1166 void DumperSupport::dump_instance_field_descriptors(AbstractDumpWriter* writer, Klass* k) {
1167 InstanceKlass* ik = InstanceKlass::cast(k);
1168
1169 // dump the field descriptors
1170 for (JavaFieldStream fld(ik); !fld.done(); fld.next()) {
1171 if (!fld.access_flags().is_static()) {
1172 Symbol* sig = fld.signature();
1173
1174 writer->write_symbolID(fld.name()); // name
1175 writer->write_u1(sig2tag(sig)); // type
1176 }
1177 }
1178 }
1179
1180 // creates HPROF_GC_INSTANCE_DUMP record for the given object
1181 void DumperSupport::dump_instance(AbstractDumpWriter* writer, oop o, DumperClassCacheTable* class_cache) {
1182 InstanceKlass* ik = InstanceKlass::cast(o->klass());
1183
1184 DumperClassCacheTableEntry* cache_entry = class_cache->lookup_or_create(ik);
1185
1186 u4 is = instance_size(ik, cache_entry);
1187 u4 size = 1 + sizeof(address) + 4 + sizeof(address) + 4 + is;
1188
1189 writer->start_sub_record(HPROF_GC_INSTANCE_DUMP, size);
1190 writer->write_objectID(o);
1191 writer->write_u4(STACK_TRACE_ID);
1192
1193 // class ID
1194 writer->write_classID(ik);
1195
1196 // number of bytes that follow
1197 writer->write_u4(is);
1198
1199 // field values
1200 dump_instance_fields(writer, o, cache_entry);
1201
1202 writer->end_sub_record();
1203 }
1204
1205 // creates HPROF_GC_CLASS_DUMP record for the given instance class
1206 void DumperSupport::dump_instance_class(AbstractDumpWriter* writer, Klass* k) {
1207 InstanceKlass* ik = InstanceKlass::cast(k);
1208
1209 // We can safepoint and do a heap dump at a point where we have a Klass,
1210 // but no java mirror class has been setup for it. So we need to check
1211 // that the class is at least loaded, to avoid crash from a null mirror.
1212 if (!ik->is_loaded()) {
1213 return;
1214 }
1215
1216 u2 static_fields_count = 0;
1217 u4 static_size = get_static_fields_size(ik, static_fields_count);
1218 u2 instance_fields_count = get_instance_fields_count(ik);
1219 u4 instance_fields_size = instance_fields_count * (sizeof(address) + 1);
1220 u4 size = checked_cast<u4>(1 + sizeof(address) + 4 + 6 * sizeof(address) + 4 + 2 + 2 + static_size + 2 + instance_fields_size);
1221
1222 writer->start_sub_record(HPROF_GC_CLASS_DUMP, size);
1223
1224 // class ID
1225 writer->write_classID(ik);
1226 writer->write_u4(STACK_TRACE_ID);
1227
1228 // super class ID
1229 InstanceKlass* java_super = ik->java_super();
1230 if (java_super == nullptr) {
1231 writer->write_objectID(oop(nullptr));
1232 } else {
1233 writer->write_classID(java_super);
1234 }
1235
1236 writer->write_objectID(ik->class_loader());
1237 writer->write_objectID(ik->signers());
1238 writer->write_objectID(ik->protection_domain());
1239
1240 // reserved
1241 writer->write_objectID(oop(nullptr));
1242 writer->write_objectID(oop(nullptr));
1243
1244 // instance size
1245 writer->write_u4(DumperSupport::instance_size(ik));
1246
1247 // size of constant pool - ignored by HAT 1.1
1248 writer->write_u2(0);
1249
1250 // static fields
1251 writer->write_u2(static_fields_count);
1252 dump_static_fields(writer, ik);
1253
1254 // description of instance fields
1255 writer->write_u2(instance_fields_count);
1256 dump_instance_field_descriptors(writer, ik);
1257
1258 writer->end_sub_record();
1259 }
1260
1261 // creates HPROF_GC_CLASS_DUMP record for the given array class
1262 void DumperSupport::dump_array_class(AbstractDumpWriter* writer, Klass* k) {
1263 InstanceKlass* ik = nullptr; // bottom class for object arrays, null for primitive type arrays
1264 if (k->is_objArray_klass()) {
1265 Klass *bk = ObjArrayKlass::cast(k)->bottom_klass();
1266 assert(bk != nullptr, "checking");
1267 if (bk->is_instance_klass()) {
1268 ik = InstanceKlass::cast(bk);
1269 }
1270 }
1271
1272 u4 size = 1 + sizeof(address) + 4 + 6 * sizeof(address) + 4 + 2 + 2 + 2;
1273 writer->start_sub_record(HPROF_GC_CLASS_DUMP, size);
1274 writer->write_classID(k);
1275 writer->write_u4(STACK_TRACE_ID);
1276
1277 // super class of array classes is java.lang.Object
1278 InstanceKlass* java_super = k->java_super();
1279 assert(java_super != nullptr, "checking");
1280 writer->write_classID(java_super);
1281
1282 writer->write_objectID(ik == nullptr ? oop(nullptr) : ik->class_loader());
1283 writer->write_objectID(ik == nullptr ? oop(nullptr) : ik->signers());
1284 writer->write_objectID(ik == nullptr ? oop(nullptr) : ik->protection_domain());
1285
1286 writer->write_objectID(oop(nullptr)); // reserved
1287 writer->write_objectID(oop(nullptr));
1288 writer->write_u4(0); // instance size
1289 writer->write_u2(0); // constant pool
1290 writer->write_u2(0); // static fields
1291 writer->write_u2(0); // instance fields
1292
1293 writer->end_sub_record();
1294
1295 }
1296
1297 // Hprof uses an u4 as record length field,
1298 // which means we need to truncate arrays that are too long.
1299 int DumperSupport::calculate_array_max_length(AbstractDumpWriter* writer, arrayOop array, short header_size) {
1300 BasicType type = ArrayKlass::cast(array->klass())->element_type();
1301 assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type");
1302
1303 int length = array->length();
1304
1305 int type_size;
1306 if (type == T_OBJECT) {
1307 type_size = sizeof(address);
1308 } else {
1309 type_size = type2aelembytes(type);
1310 }
1311
1312 size_t length_in_bytes = (size_t)length * type_size;
1313 uint max_bytes = max_juint - header_size;
1314
1315 if (length_in_bytes > max_bytes) {
1316 length = max_bytes / type_size;
1317 length_in_bytes = (size_t)length * type_size;
1318
1319 warning("cannot dump array of type %s[] with length %d; truncating to length %d",
1320 type2name_tab[type], array->length(), length);
1321 }
1322 return length;
1323 }
1324
1325 // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
1326 void DumperSupport::dump_object_array(AbstractDumpWriter* writer, objArrayOop array) {
1327 // sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID) + sizeof(classID)
1328 short header_size = 1 + 2 * 4 + 2 * sizeof(address);
1329 int length = calculate_array_max_length(writer, array, header_size);
1330 u4 size = checked_cast<u4>(header_size + length * sizeof(address));
1331
1332 writer->start_sub_record(HPROF_GC_OBJ_ARRAY_DUMP, size);
1333 writer->write_objectID(array);
1334 writer->write_u4(STACK_TRACE_ID);
1335 writer->write_u4(length);
1336
1337 // array class ID
1338 writer->write_classID(array->klass());
1339
1340 // [id]* elements
1341 for (int index = 0; index < length; index++) {
1342 oop o = array->obj_at(index);
1343 o = mask_dormant_archived_object(o, array);
1344 writer->write_objectID(o);
1345 }
1346
1347 writer->end_sub_record();
1348 }
1349
1350 #define WRITE_ARRAY(Array, Type, Size, Length) \
1351 for (int i = 0; i < Length; i++) { writer->write_##Size((Size)Array->Type##_at(i)); }
1352
1353 // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
1354 void DumperSupport::dump_prim_array(AbstractDumpWriter* writer, typeArrayOop array) {
1355 BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
1356 // 2 * sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID)
1357 short header_size = 2 * 1 + 2 * 4 + sizeof(address);
1358
1359 int length = calculate_array_max_length(writer, array, header_size);
1360 int type_size = type2aelembytes(type);
1361 u4 length_in_bytes = (u4)length * type_size;
1362 u4 size = header_size + length_in_bytes;
1363
1364 writer->start_sub_record(HPROF_GC_PRIM_ARRAY_DUMP, size);
1365 writer->write_objectID(array);
1366 writer->write_u4(STACK_TRACE_ID);
1367 writer->write_u4(length);
1368 writer->write_u1(type2tag(type));
1369
1370 // nothing to copy
1371 if (length == 0) {
1372 writer->end_sub_record();
1373 return;
1374 }
1375
1376 // If the byte ordering is big endian then we can copy most types directly
1377
1378 switch (type) {
1379 case T_INT : {
1380 if (Endian::is_Java_byte_ordering_different()) {
1381 WRITE_ARRAY(array, int, u4, length);
1382 } else {
1383 writer->write_raw(array->int_at_addr(0), length_in_bytes);
1384 }
1385 break;
1386 }
1387 case T_BYTE : {
1388 writer->write_raw(array->byte_at_addr(0), length_in_bytes);
1389 break;
1390 }
1391 case T_CHAR : {
1392 if (Endian::is_Java_byte_ordering_different()) {
1393 WRITE_ARRAY(array, char, u2, length);
1394 } else {
1395 writer->write_raw(array->char_at_addr(0), length_in_bytes);
1396 }
1397 break;
1398 }
1399 case T_SHORT : {
1400 if (Endian::is_Java_byte_ordering_different()) {
1401 WRITE_ARRAY(array, short, u2, length);
1402 } else {
1403 writer->write_raw(array->short_at_addr(0), length_in_bytes);
1404 }
1405 break;
1406 }
1407 case T_BOOLEAN : {
1408 if (Endian::is_Java_byte_ordering_different()) {
1409 WRITE_ARRAY(array, bool, u1, length);
1410 } else {
1411 writer->write_raw(array->bool_at_addr(0), length_in_bytes);
1412 }
1413 break;
1414 }
1415 case T_LONG : {
1416 if (Endian::is_Java_byte_ordering_different()) {
1417 WRITE_ARRAY(array, long, u8, length);
1418 } else {
1419 writer->write_raw(array->long_at_addr(0), length_in_bytes);
1420 }
1421 break;
1422 }
1423
1424 // handle float/doubles in a special value to ensure than NaNs are
1425 // written correctly. TO DO: Check if we can avoid this on processors that
1426 // use IEEE 754.
1427
1428 case T_FLOAT : {
1429 for (int i = 0; i < length; i++) {
1430 dump_float(writer, array->float_at(i));
1431 }
1432 break;
1433 }
1434 case T_DOUBLE : {
1435 for (int i = 0; i < length; i++) {
1436 dump_double(writer, array->double_at(i));
1437 }
1438 break;
1439 }
1440 default : ShouldNotReachHere();
1441 }
1442
1443 writer->end_sub_record();
1444 }
1445
1446 // create a HPROF_FRAME record of the given Method* and bci
1447 void DumperSupport::dump_stack_frame(AbstractDumpWriter* writer,
1448 int frame_serial_num,
1449 int class_serial_num,
1450 Method* m,
1451 int bci) {
1452 int line_number;
1453 if (m->is_native()) {
1454 line_number = -3; // native frame
1455 } else {
1456 line_number = m->line_number_from_bci(bci);
1457 }
1458
1459 write_header(writer, HPROF_FRAME, 4*oopSize + 2*sizeof(u4));
1460 writer->write_id(frame_serial_num); // frame serial number
1461 writer->write_symbolID(m->name()); // method's name
1462 writer->write_symbolID(m->signature()); // method's signature
1463
1464 assert(m->method_holder()->is_instance_klass(), "not InstanceKlass");
1465 writer->write_symbolID(m->method_holder()->source_file_name()); // source file name
1466 writer->write_u4(class_serial_num); // class serial number
1467 writer->write_u4((u4) line_number); // line number
1468 }
1469
1470
1471 // Support class used to generate HPROF_UTF8 records from the entries in the
1472 // SymbolTable.
1473
1474 class SymbolTableDumper : public SymbolClosure {
1475 private:
1476 AbstractDumpWriter* _writer;
1477 AbstractDumpWriter* writer() const { return _writer; }
1478 public:
1479 SymbolTableDumper(AbstractDumpWriter* writer) { _writer = writer; }
1480 void do_symbol(Symbol** p);
1481 };
1482
1483 void SymbolTableDumper::do_symbol(Symbol** p) {
1484 ResourceMark rm;
1485 Symbol* sym = *p;
1486 int len = sym->utf8_length();
1487 if (len > 0) {
1488 char* s = sym->as_utf8();
1489 DumperSupport::write_header(writer(), HPROF_UTF8, oopSize + len);
1490 writer()->write_symbolID(sym);
1491 writer()->write_raw(s, len);
1492 }
1493 }
1494
1495 // Support class used to generate HPROF_GC_CLASS_DUMP records
1496
1497 class ClassDumper : public KlassClosure {
1498 private:
1499 AbstractDumpWriter* _writer;
1500 AbstractDumpWriter* writer() const { return _writer; }
1501
1502 public:
1503 ClassDumper(AbstractDumpWriter* writer) : _writer(writer) {}
1504
1505 void do_klass(Klass* k) {
1506 if (k->is_instance_klass()) {
1507 DumperSupport::dump_instance_class(writer(), k);
1508 } else {
1509 DumperSupport::dump_array_class(writer(), k);
1510 }
1511 }
1512 };
1513
1514 // Support class used to generate HPROF_LOAD_CLASS records
1515
1516 class LoadedClassDumper : public LockedClassesDo {
1517 private:
1518 AbstractDumpWriter* _writer;
1519 GrowableArray<Klass*>* _klass_map;
1520 u4 _class_serial_num;
1521 AbstractDumpWriter* writer() const { return _writer; }
1522 void add_class_serial_number(Klass* k, int serial_num) {
1523 _klass_map->at_put_grow(serial_num, k);
1524 }
1525 public:
1526 LoadedClassDumper(AbstractDumpWriter* writer, GrowableArray<Klass*>* klass_map)
1527 : _writer(writer), _klass_map(klass_map), _class_serial_num(0) {}
1528
1529 void do_klass(Klass* k) {
1530 // len of HPROF_LOAD_CLASS record
1531 u4 remaining = 2 * oopSize + 2 * sizeof(u4);
1532 DumperSupport::write_header(writer(), HPROF_LOAD_CLASS, remaining);
1533 // class serial number is just a number
1534 writer()->write_u4(++_class_serial_num);
1535 // class ID
1536 writer()->write_classID(k);
1537 // add the Klass* and class serial number pair
1538 add_class_serial_number(k, _class_serial_num);
1539 writer()->write_u4(STACK_TRACE_ID);
1540 // class name ID
1541 Symbol* name = k->name();
1542 writer()->write_symbolID(name);
1543 }
1544 };
1545
1546 // Support class used to generate HPROF_GC_ROOT_JNI_LOCAL records
1547
1548 class JNILocalsDumper : public OopClosure {
1549 private:
1550 AbstractDumpWriter* _writer;
1551 u4 _thread_serial_num;
1552 int _frame_num;
1553 AbstractDumpWriter* writer() const { return _writer; }
1554 public:
1555 JNILocalsDumper(AbstractDumpWriter* writer, u4 thread_serial_num) {
1556 _writer = writer;
1557 _thread_serial_num = thread_serial_num;
1558 _frame_num = -1; // default - empty stack
1559 }
1560 void set_frame_number(int n) { _frame_num = n; }
1561 void do_oop(oop* obj_p);
1562 void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1563 };
1564
1565 void JNILocalsDumper::do_oop(oop* obj_p) {
1566 // ignore null handles
1567 oop o = *obj_p;
1568 if (o != nullptr) {
1569 u4 size = 1 + sizeof(address) + 4 + 4;
1570 writer()->start_sub_record(HPROF_GC_ROOT_JNI_LOCAL, size);
1571 writer()->write_objectID(o);
1572 writer()->write_u4(_thread_serial_num);
1573 writer()->write_u4((u4)_frame_num);
1574 writer()->end_sub_record();
1575 }
1576 }
1577
1578
1579 // Support class used to generate HPROF_GC_ROOT_JNI_GLOBAL records
1580
1581 class JNIGlobalsDumper : public OopClosure {
1582 private:
1583 AbstractDumpWriter* _writer;
1584 AbstractDumpWriter* writer() const { return _writer; }
1585
1586 public:
1587 JNIGlobalsDumper(AbstractDumpWriter* writer) {
1588 _writer = writer;
1589 }
1590 void do_oop(oop* obj_p);
1591 void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1592 };
1593
1594 void JNIGlobalsDumper::do_oop(oop* obj_p) {
1595 oop o = NativeAccess<AS_NO_KEEPALIVE>::oop_load(obj_p);
1596
1597 // ignore these
1598 if (o == nullptr) return;
1599 // we ignore global ref to symbols and other internal objects
1600 if (o->is_instance() || o->is_objArray() || o->is_typeArray()) {
1601 u4 size = 1 + 2 * sizeof(address);
1602 writer()->start_sub_record(HPROF_GC_ROOT_JNI_GLOBAL, size);
1603 writer()->write_objectID(o);
1604 writer()->write_rootID(obj_p); // global ref ID
1605 writer()->end_sub_record();
1606 }
1607 };
1608
1609 // Support class used to generate HPROF_GC_ROOT_STICKY_CLASS records
1610
1611 class StickyClassDumper : public KlassClosure {
1612 private:
1613 AbstractDumpWriter* _writer;
1614 AbstractDumpWriter* writer() const { return _writer; }
1615 public:
1616 StickyClassDumper(AbstractDumpWriter* writer) {
1617 _writer = writer;
1618 }
1619 void do_klass(Klass* k) {
1620 if (k->is_instance_klass()) {
1621 InstanceKlass* ik = InstanceKlass::cast(k);
1622 u4 size = 1 + sizeof(address);
1623 writer()->start_sub_record(HPROF_GC_ROOT_STICKY_CLASS, size);
1624 writer()->write_classID(ik);
1625 writer()->end_sub_record();
1626 }
1627 }
1628 };
1629
1630 // Support class used to generate HPROF_GC_ROOT_JAVA_FRAME records.
1631
1632 class JavaStackRefDumper : public StackObj {
1633 private:
1634 AbstractDumpWriter* _writer;
1635 u4 _thread_serial_num;
1636 int _frame_num;
1637 AbstractDumpWriter* writer() const { return _writer; }
1638 public:
1639 JavaStackRefDumper(AbstractDumpWriter* writer, u4 thread_serial_num)
1640 : _writer(writer), _thread_serial_num(thread_serial_num), _frame_num(-1) // default - empty stack
1641 {
1642 }
1643
1644 void set_frame_number(int n) { _frame_num = n; }
1645
1646 void dump_java_stack_refs(StackValueCollection* values);
1647 };
1648
1649 void JavaStackRefDumper::dump_java_stack_refs(StackValueCollection* values) {
1650 for (int index = 0; index < values->size(); index++) {
1651 if (values->at(index)->type() == T_OBJECT) {
1652 oop o = values->obj_at(index)();
1653 if (o != nullptr) {
1654 u4 size = 1 + sizeof(address) + 4 + 4;
1655 writer()->start_sub_record(HPROF_GC_ROOT_JAVA_FRAME, size);
1656 writer()->write_objectID(o);
1657 writer()->write_u4(_thread_serial_num);
1658 writer()->write_u4((u4)_frame_num);
1659 writer()->end_sub_record();
1660 }
1661 }
1662 }
1663 }
1664
1665 // Class to collect, store and dump thread-related data:
1666 // - HPROF_TRACE and HPROF_FRAME records;
1667 // - HPROF_GC_ROOT_THREAD_OBJ/HPROF_GC_ROOT_JAVA_FRAME/HPROF_GC_ROOT_JNI_LOCAL subrecords.
1668 class ThreadDumper : public CHeapObj<mtInternal> {
1669 public:
1670 enum class ThreadType { Platform, MountedVirtual, UnmountedVirtual };
1671
1672 private:
1673 ThreadType _thread_type;
1674 JavaThread* _java_thread;
1675 oop _thread_oop;
1676
1677 GrowableArray<StackFrameInfo*>* _frames;
1678 // non-null if the thread is OOM thread
1679 Method* _oome_constructor;
1680 int _thread_serial_num;
1681 int _start_frame_serial_num;
1682
1683 vframe* get_top_frame() const;
1684
1685 public:
1686 static bool should_dump_pthread(JavaThread* thread) {
1687 return thread->threadObj() != nullptr && !thread->is_exiting() && !thread->is_hidden_from_external_view();
1688 }
1689
1690 static bool should_dump_vthread(oop vt) {
1691 return java_lang_VirtualThread::state(vt) != java_lang_VirtualThread::NEW
1692 && java_lang_VirtualThread::state(vt) != java_lang_VirtualThread::TERMINATED;
1693 }
1694
1695 static bool is_vthread_mounted(oop vt) {
1696 // The code should be consistent with the "mounted virtual thread" case
1697 // (VM_HeapDumper::dump_stack_traces(), ThreadDumper::get_top_frame()).
1698 // I.e. virtual thread is mounted if its carrierThread is not null
1699 // and is_vthread_mounted() for the carrier thread returns true.
1700 oop carrier_thread = java_lang_VirtualThread::carrier_thread(vt);
1701 if (carrier_thread == nullptr) {
1702 return false;
1703 }
1704 JavaThread* java_thread = java_lang_Thread::thread(carrier_thread);
1705 return java_thread->is_vthread_mounted();
1706 }
1707
1708 ThreadDumper(ThreadType thread_type, JavaThread* java_thread, oop thread_oop);
1709 ~ThreadDumper() {
1710 for (int index = 0; index < _frames->length(); index++) {
1711 delete _frames->at(index);
1712 }
1713 delete _frames;
1714 }
1715
1716 // affects frame_count
1717 void add_oom_frame(Method* oome_constructor) {
1718 assert(_start_frame_serial_num == 0, "add_oom_frame cannot be called after init_serial_nums");
1719 _oome_constructor = oome_constructor;
1720 }
1721
1722 void init_serial_nums(volatile int* thread_counter, volatile int* frame_counter) {
1723 assert(_start_frame_serial_num == 0, "already initialized");
1724 _thread_serial_num = Atomic::fetch_then_add(thread_counter, 1);
1725 _start_frame_serial_num = Atomic::fetch_then_add(frame_counter, frame_count());
1726 }
1727
1728 bool oom_thread() const {
1729 return _oome_constructor != nullptr;
1730 }
1731
1732 int frame_count() const {
1733 return _frames->length() + (oom_thread() ? 1 : 0);
1734 }
1735
1736 u4 thread_serial_num() const {
1737 return (u4)_thread_serial_num;
1738 }
1739
1740 u4 stack_trace_serial_num() const {
1741 return (u4)(_thread_serial_num + STACK_TRACE_ID);
1742 }
1743
1744 // writes HPROF_TRACE and HPROF_FRAME records
1745 // returns number of dumped frames
1746 void dump_stack_traces(AbstractDumpWriter* writer, GrowableArray<Klass*>* klass_map);
1747
1748 // writes HPROF_GC_ROOT_THREAD_OBJ subrecord
1749 void dump_thread_obj(AbstractDumpWriter* writer);
1750
1751 // Walk the stack of the thread.
1752 // Dumps a HPROF_GC_ROOT_JAVA_FRAME subrecord for each local
1753 // Dumps a HPROF_GC_ROOT_JNI_LOCAL subrecord for each JNI local
1754 void dump_stack_refs(AbstractDumpWriter* writer);
1755
1756 };
1757
1758 ThreadDumper::ThreadDumper(ThreadType thread_type, JavaThread* java_thread, oop thread_oop)
1759 : _thread_type(thread_type), _java_thread(java_thread), _thread_oop(thread_oop),
1760 _oome_constructor(nullptr),
1761 _thread_serial_num(0), _start_frame_serial_num(0)
1762 {
1763 // sanity checks
1764 if (_thread_type == ThreadType::UnmountedVirtual) {
1765 assert(_java_thread == nullptr, "sanity");
1766 assert(_thread_oop != nullptr, "sanity");
1767 } else {
1768 assert(_java_thread != nullptr, "sanity");
1769 assert(_thread_oop != nullptr, "sanity");
1770 }
1771
1772 _frames = new (mtServiceability) GrowableArray<StackFrameInfo*>(10, mtServiceability);
1773 bool stop_at_vthread_entry = _thread_type == ThreadType::MountedVirtual;
1774
1775 // vframes are resource allocated
1776 Thread* current_thread = Thread::current();
1777 ResourceMark rm(current_thread);
1778 HandleMark hm(current_thread);
1779
1780 for (vframe* vf = get_top_frame(); vf != nullptr; vf = vf->sender()) {
1781 if (stop_at_vthread_entry && vf->is_vthread_entry()) {
1782 break;
1783 }
1784 if (vf->is_java_frame()) {
1785 javaVFrame* jvf = javaVFrame::cast(vf);
1786 _frames->append(new StackFrameInfo(jvf, false));
1787 } else {
1788 // ignore non-Java frames
1789 }
1790 }
1791 }
1792
1793 void ThreadDumper::dump_stack_traces(AbstractDumpWriter* writer, GrowableArray<Klass*>* klass_map) {
1794 assert(_thread_serial_num != 0 && _start_frame_serial_num != 0, "serial_nums are not initialized");
1795
1796 // write HPROF_FRAME records for this thread's stack trace
1797 int depth = _frames->length();
1798 int frame_serial_num = _start_frame_serial_num;
1799
1800 if (oom_thread()) {
1801 // OOM thread
1802 // write fake frame that makes it look like the thread, which caused OOME,
1803 // is in the OutOfMemoryError zero-parameter constructor
1804 int oome_serial_num = klass_map->find(_oome_constructor->method_holder());
1805 // the class serial number starts from 1
1806 assert(oome_serial_num > 0, "OutOfMemoryError class not found");
1807 DumperSupport::dump_stack_frame(writer, ++frame_serial_num, oome_serial_num, _oome_constructor, 0);
1808 depth++;
1809 }
1810
1811 for (int j = 0; j < _frames->length(); j++) {
1812 StackFrameInfo* frame = _frames->at(j);
1813 Method* m = frame->method();
1814 int class_serial_num = klass_map->find(m->method_holder());
1815 // the class serial number starts from 1
1816 assert(class_serial_num > 0, "class not found");
1817 DumperSupport::dump_stack_frame(writer, ++frame_serial_num, class_serial_num, m, frame->bci());
1818 }
1819
1820 // write HPROF_TRACE record for the thread
1821 DumperSupport::write_header(writer, HPROF_TRACE, checked_cast<u4>(3 * sizeof(u4) + depth * oopSize));
1822 writer->write_u4(stack_trace_serial_num()); // stack trace serial number
1823 writer->write_u4(thread_serial_num()); // thread serial number
1824 writer->write_u4((u4)depth); // frame count (including oom frame)
1825 for (int j = 1; j <= depth; j++) {
1826 writer->write_id(_start_frame_serial_num + j);
1827 }
1828 }
1829
1830 void ThreadDumper::dump_thread_obj(AbstractDumpWriter * writer) {
1831 assert(_thread_serial_num != 0 && _start_frame_serial_num != 0, "serial_num is not initialized");
1832
1833 u4 size = 1 + sizeof(address) + 4 + 4;
1834 writer->start_sub_record(HPROF_GC_ROOT_THREAD_OBJ, size);
1835 writer->write_objectID(_thread_oop);
1836 writer->write_u4(thread_serial_num()); // thread serial number
1837 writer->write_u4(stack_trace_serial_num()); // stack trace serial number
1838 writer->end_sub_record();
1839 }
1840
1841 void ThreadDumper::dump_stack_refs(AbstractDumpWriter * writer) {
1842 assert(_thread_serial_num != 0 && _start_frame_serial_num != 0, "serial_num is not initialized");
1843
1844 JNILocalsDumper blk(writer, thread_serial_num());
1845 if (_thread_type == ThreadType::Platform) {
1846 if (!_java_thread->has_last_Java_frame()) {
1847 // no last java frame but there may be JNI locals
1848 _java_thread->active_handles()->oops_do(&blk);
1849 return;
1850 }
1851 }
1852
1853 JavaStackRefDumper java_ref_dumper(writer, thread_serial_num());
1854
1855 // vframes are resource allocated
1856 Thread* current_thread = Thread::current();
1857 ResourceMark rm(current_thread);
1858 HandleMark hm(current_thread);
1859
1860 bool stopAtVthreadEntry = _thread_type == ThreadType::MountedVirtual;
1861 frame* last_entry_frame = nullptr;
1862 bool is_top_frame = true;
1863 int depth = 0;
1864 if (oom_thread()) {
1865 depth++;
1866 }
1867
1868 for (vframe* vf = get_top_frame(); vf != nullptr; vf = vf->sender()) {
1869 if (stopAtVthreadEntry && vf->is_vthread_entry()) {
1870 break;
1871 }
1872
1873 if (vf->is_java_frame()) {
1874 javaVFrame* jvf = javaVFrame::cast(vf);
1875 if (!(jvf->method()->is_native())) {
1876 java_ref_dumper.set_frame_number(depth);
1877 java_ref_dumper.dump_java_stack_refs(jvf->locals());
1878 java_ref_dumper.dump_java_stack_refs(jvf->expressions());
1879 } else {
1880 // native frame
1881 blk.set_frame_number(depth);
1882 if (is_top_frame) {
1883 // JNI locals for the top frame if mounted
1884 assert(_java_thread != nullptr || jvf->method()->is_synchronized()
1885 || jvf->method()->is_object_wait0(), "impossible for unmounted vthread");
1886 if (_java_thread != nullptr) {
1887 _java_thread->active_handles()->oops_do(&blk);
1888 }
1889 } else {
1890 if (last_entry_frame != nullptr) {
1891 // JNI locals for the entry frame
1892 assert(last_entry_frame->is_entry_frame(), "checking");
1893 last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(&blk);
1894 }
1895 }
1896 }
1897 last_entry_frame = nullptr;
1898 // increment only for Java frames
1899 depth++;
1900 } else {
1901 // externalVFrame - for an entry frame then we report the JNI locals
1902 // when we find the corresponding javaVFrame
1903 frame* fr = vf->frame_pointer();
1904 assert(fr != nullptr, "sanity check");
1905 if (fr->is_entry_frame()) {
1906 last_entry_frame = fr;
1907 }
1908 }
1909 is_top_frame = false;
1910 }
1911 assert(depth == frame_count(), "total number of Java frames not matched");
1912 }
1913
1914 vframe* ThreadDumper::get_top_frame() const {
1915 if (_thread_type == ThreadType::UnmountedVirtual) {
1916 ContinuationWrapper cont(java_lang_VirtualThread::continuation(_thread_oop));
1917 if (cont.is_empty()) {
1918 return nullptr;
1919 }
1920 assert(!cont.is_mounted(), "sanity check");
1921 stackChunkOop chunk = cont.last_nonempty_chunk();
1922 if (chunk == nullptr || chunk->is_empty()) {
1923 return nullptr;
1924 }
1925
1926 RegisterMap reg_map(cont.continuation(), RegisterMap::UpdateMap::include);
1927 frame fr = chunk->top_frame(®_map);
1928 vframe* vf = vframe::new_vframe(&fr, ®_map, nullptr); // don't need JavaThread
1929 return vf;
1930 }
1931
1932 RegisterMap reg_map(_java_thread,
1933 RegisterMap::UpdateMap::include,
1934 RegisterMap::ProcessFrames::include,
1935 RegisterMap::WalkContinuation::skip);
1936 switch (_thread_type) {
1937 case ThreadType::Platform:
1938 if (!_java_thread->has_last_Java_frame()) {
1939 return nullptr;
1940 }
1941 return _java_thread->is_vthread_mounted()
1942 ? _java_thread->carrier_last_java_vframe(®_map)
1943 : _java_thread->platform_thread_last_java_vframe(®_map);
1944
1945 case ThreadType::MountedVirtual:
1946 return _java_thread->last_java_vframe(®_map);
1947
1948 default: // make compilers happy
1949 break;
1950 }
1951 ShouldNotReachHere();
1952 return nullptr;
1953 }
1954
1955 // Callback to dump thread-related data for unmounted virtual threads;
1956 // implemented by VM_HeapDumper.
1957 class UnmountedVThreadDumper {
1958 public:
1959 virtual void dump_vthread(oop vt, AbstractDumpWriter* segment_writer) = 0;
1960 };
1961
1962 // Support class used when iterating over the heap.
1963 class HeapObjectDumper : public ObjectClosure {
1964 private:
1965 AbstractDumpWriter* _writer;
1966 AbstractDumpWriter* writer() { return _writer; }
1967 UnmountedVThreadDumper* _vthread_dumper;
1968
1969 DumperClassCacheTable _class_cache;
1970
1971 public:
1972 HeapObjectDumper(AbstractDumpWriter* writer, UnmountedVThreadDumper* vthread_dumper)
1973 : _writer(writer), _vthread_dumper(vthread_dumper) {}
1974
1975 // called for each object in the heap
1976 void do_object(oop o);
1977 };
1978
1979 void HeapObjectDumper::do_object(oop o) {
1980 // skip classes as these emitted as HPROF_GC_CLASS_DUMP records
1981 if (o->klass() == vmClasses::Class_klass()) {
1982 if (!java_lang_Class::is_primitive(o)) {
1983 return;
1984 }
1985 }
1986
1987 if (DumperSupport::mask_dormant_archived_object(o, nullptr) == nullptr) {
1988 return;
1989 }
1990
1991 if (o->is_instance()) {
1992 // create a HPROF_GC_INSTANCE record for each object
1993 DumperSupport::dump_instance(writer(), o, &_class_cache);
1994 // If we encounter an unmounted virtual thread it needs to be dumped explicitly
1995 // (mounted virtual threads are dumped with their carriers).
1996 if (java_lang_VirtualThread::is_instance(o)
1997 && ThreadDumper::should_dump_vthread(o) && !ThreadDumper::is_vthread_mounted(o)) {
1998 _vthread_dumper->dump_vthread(o, writer());
1999 }
2000 } else if (o->is_objArray()) {
2001 // create a HPROF_GC_OBJ_ARRAY_DUMP record for each object array
2002 DumperSupport::dump_object_array(writer(), objArrayOop(o));
2003 } else if (o->is_typeArray()) {
2004 // create a HPROF_GC_PRIM_ARRAY_DUMP record for each type array
2005 DumperSupport::dump_prim_array(writer(), typeArrayOop(o));
2006 }
2007 }
2008
2009 // The dumper controller for parallel heap dump
2010 class DumperController : public CHeapObj<mtInternal> {
2011 private:
2012 Monitor* _lock;
2013 Mutex* _global_writer_lock;
2014
2015 const uint _dumper_number;
2016 uint _complete_number;
2017
2018 bool _started; // VM dumper started and acquired global writer lock
2019
2020 public:
2021 DumperController(uint number) :
2022 // _lock and _global_writer_lock are used for synchronization between GC worker threads inside safepoint,
2023 // so we lock with _no_safepoint_check_flag.
2024 // signal_start() acquires _lock when global writer is locked,
2025 // its rank must be less than _global_writer_lock rank.
2026 _lock(new (std::nothrow) PaddedMonitor(Mutex::nosafepoint - 1, "DumperController_lock")),
2027 _global_writer_lock(new (std::nothrow) Mutex(Mutex::nosafepoint, "DumpWriter_lock")),
2028 _dumper_number(number),
2029 _complete_number(0),
2030 _started(false)
2031 {}
2032
2033 ~DumperController() {
2034 delete _lock;
2035 delete _global_writer_lock;
2036 }
2037
2038 // parallel (non VM) dumpers must wait until VM dumper acquires global writer lock
2039 void wait_for_start_signal() {
2040 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
2041 while (_started == false) {
2042 ml.wait();
2043 }
2044 }
2045
2046 void signal_start() {
2047 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
2048 _started = true;
2049 ml.notify_all();
2050 }
2051
2052 void lock_global_writer() {
2053 _global_writer_lock->lock_without_safepoint_check();
2054 }
2055
2056 void unlock_global_writer() {
2057 _global_writer_lock->unlock();
2058 }
2059
2060 void dumper_complete(DumpWriter* local_writer, DumpWriter* global_writer) {
2061 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
2062 _complete_number++;
2063 // propagate local error to global if any
2064 if (local_writer->has_error()) {
2065 global_writer->set_error(local_writer->error());
2066 }
2067 ml.notify();
2068 }
2069
2070 void wait_all_dumpers_complete() {
2071 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
2072 while (_complete_number != _dumper_number) {
2073 ml.wait();
2074 }
2075 }
2076 };
2077
2078 // DumpMerger merges separate dump files into a complete one
2079 class DumpMerger : public StackObj {
2080 private:
2081 DumpWriter* _writer;
2082 const char* _path;
2083 bool _has_error;
2084 int _dump_seq;
2085
2086 private:
2087 void merge_file(const char* path);
2088 void merge_done();
2089 void set_error(const char* msg);
2090
2091 public:
2092 DumpMerger(const char* path, DumpWriter* writer, int dump_seq) :
2093 _writer(writer),
2094 _path(path),
2095 _has_error(_writer->has_error()),
2096 _dump_seq(dump_seq) {}
2097
2098 void do_merge();
2099
2100 // returns path for the parallel DumpWriter (resource allocated)
2101 static char* get_writer_path(const char* base_path, int seq);
2102
2103 };
2104
2105 char* DumpMerger::get_writer_path(const char* base_path, int seq) {
2106 // approximate required buffer size
2107 size_t buf_size = strlen(base_path)
2108 + 2 // ".p"
2109 + 10 // number (that's enough for 2^32 parallel dumpers)
2110 + 1; // '\0'
2111
2112 char* path = NEW_RESOURCE_ARRAY(char, buf_size);
2113 memset(path, 0, buf_size);
2114
2115 os::snprintf(path, buf_size, "%s.p%d", base_path, seq);
2116
2117 return path;
2118 }
2119
2120
2121 void DumpMerger::merge_done() {
2122 // Writes the HPROF_HEAP_DUMP_END record.
2123 if (!_has_error) {
2124 DumperSupport::end_of_dump(_writer);
2125 _writer->flush();
2126 }
2127 _dump_seq = 0; //reset
2128 }
2129
2130 void DumpMerger::set_error(const char* msg) {
2131 assert(msg != nullptr, "sanity check");
2132 log_error(heapdump)("%s (file: %s)", msg, _path);
2133 _writer->set_error(msg);
2134 _has_error = true;
2135 }
2136
2137 #ifdef LINUX
2138 // Merge segmented heap files via sendfile, it's more efficient than the
2139 // read+write combination, which would require transferring data to and from
2140 // user space.
2141 void DumpMerger::merge_file(const char* path) {
2142 TraceTime timer("Merge segmented heap file directly", TRACETIME_LOG(Info, heapdump));
2143
2144 int segment_fd = os::open(path, O_RDONLY, 0);
2145 if (segment_fd == -1) {
2146 set_error("Can not open segmented heap file during merging");
2147 return;
2148 }
2149
2150 struct stat st;
2151 if (os::stat(path, &st) != 0) {
2152 ::close(segment_fd);
2153 set_error("Can not get segmented heap file size during merging");
2154 return;
2155 }
2156
2157 // A successful call to sendfile may write fewer bytes than requested; the
2158 // caller should be prepared to retry the call if there were unsent bytes.
2159 jlong offset = 0;
2160 while (offset < st.st_size) {
2161 int ret = os::Linux::sendfile(_writer->get_fd(), segment_fd, &offset, st.st_size);
2162 if (ret == -1) {
2163 ::close(segment_fd);
2164 set_error("Failed to merge segmented heap file");
2165 return;
2166 }
2167 }
2168
2169 // As sendfile variant does not call the write method of the global writer,
2170 // bytes_written is also incorrect for this variant, we need to explicitly
2171 // accumulate bytes_written for the global writer in this case
2172 julong accum = _writer->bytes_written() + st.st_size;
2173 _writer->set_bytes_written(accum);
2174 ::close(segment_fd);
2175 }
2176 #else
2177 // Generic implementation using read+write
2178 void DumpMerger::merge_file(const char* path) {
2179 TraceTime timer("Merge segmented heap file", TRACETIME_LOG(Info, heapdump));
2180
2181 fileStream segment_fs(path, "rb");
2182 if (!segment_fs.is_open()) {
2183 set_error("Can not open segmented heap file during merging");
2184 return;
2185 }
2186
2187 jlong total = 0;
2188 size_t cnt = 0;
2189
2190 // Use _writer buffer for reading.
2191 while ((cnt = segment_fs.read(_writer->buffer(), 1, _writer->buffer_size())) != 0) {
2192 _writer->set_position(cnt);
2193 _writer->flush();
2194 total += cnt;
2195 }
2196
2197 if (segment_fs.fileSize() != total) {
2198 set_error("Merged heap dump is incomplete");
2199 }
2200 }
2201 #endif
2202
2203 void DumpMerger::do_merge() {
2204 TraceTime timer("Merge heap files complete", TRACETIME_LOG(Info, heapdump));
2205
2206 // Since contents in segmented heap file were already zipped, we don't need to zip
2207 // them again during merging.
2208 AbstractCompressor* saved_compressor = _writer->compressor();
2209 _writer->set_compressor(nullptr);
2210
2211 // Merge the content of the remaining files into base file. Regardless of whether
2212 // the merge process is successful or not, these segmented files will be deleted.
2213 for (int i = 0; i < _dump_seq; i++) {
2214 ResourceMark rm;
2215 const char* path = get_writer_path(_path, i);
2216 if (!_has_error) {
2217 merge_file(path);
2218 }
2219 // Delete selected segmented heap file nevertheless
2220 if (remove(path) != 0) {
2221 log_info(heapdump)("Removal of segment file (%d) failed (%d)", i, errno);
2222 }
2223 }
2224
2225 // restore compressor for further use
2226 _writer->set_compressor(saved_compressor);
2227 merge_done();
2228 }
2229
2230 // The VM operation that performs the heap dump
2231 class VM_HeapDumper : public VM_GC_Operation, public WorkerTask, public UnmountedVThreadDumper {
2232 private:
2233 DumpWriter* _writer;
2234 JavaThread* _oome_thread;
2235 Method* _oome_constructor;
2236 bool _gc_before_heap_dump;
2237 GrowableArray<Klass*>* _klass_map;
2238
2239 ThreadDumper** _thread_dumpers; // platform, carrier and mounted virtual threads
2240 int _thread_dumpers_count;
2241 volatile int _thread_serial_num;
2242 volatile int _frame_serial_num;
2243
2244 volatile int _dump_seq;
2245 // parallel heap dump support
2246 uint _num_dumper_threads;
2247 DumperController* _dumper_controller;
2248 ParallelObjectIterator* _poi;
2249
2250 // Dumper id of VMDumper thread.
2251 static const int VMDumperId = 0;
2252 // VM dumper dumps both heap and non-heap data, other dumpers dump heap-only data.
2253 static bool is_vm_dumper(int dumper_id) { return dumper_id == VMDumperId; }
2254 // the 1st dumper calling get_next_dumper_id becomes VM dumper
2255 int get_next_dumper_id() {
2256 return Atomic::fetch_then_add(&_dump_seq, 1);
2257 }
2258
2259 DumpWriter* writer() const { return _writer; }
2260
2261 bool skip_operation() const;
2262
2263 // HPROF_GC_ROOT_THREAD_OBJ records for platform and mounted virtual threads
2264 void dump_threads(AbstractDumpWriter* writer);
2265
2266 bool is_oom_thread(JavaThread* thread) const {
2267 return thread == _oome_thread && _oome_constructor != nullptr;
2268 }
2269
2270 // HPROF_TRACE and HPROF_FRAME records for platform and mounted virtual threads
2271 void dump_stack_traces(AbstractDumpWriter* writer);
2272
2273 public:
2274 VM_HeapDumper(DumpWriter* writer, bool gc_before_heap_dump, bool oome, uint num_dump_threads) :
2275 VM_GC_Operation(0 /* total collections, dummy, ignored */,
2276 GCCause::_heap_dump /* GC Cause */,
2277 0 /* total full collections, dummy, ignored */,
2278 gc_before_heap_dump),
2279 WorkerTask("dump heap") {
2280 _writer = writer;
2281 _gc_before_heap_dump = gc_before_heap_dump;
2282 _klass_map = new (mtServiceability) GrowableArray<Klass*>(INITIAL_CLASS_COUNT, mtServiceability);
2283
2284 _thread_dumpers = nullptr;
2285 _thread_dumpers_count = 0;
2286 _thread_serial_num = 1;
2287 _frame_serial_num = 1;
2288
2289 _dump_seq = VMDumperId;
2290 _num_dumper_threads = num_dump_threads;
2291 _dumper_controller = nullptr;
2292 _poi = nullptr;
2293 if (oome) {
2294 assert(!Thread::current()->is_VM_thread(), "Dump from OutOfMemoryError cannot be called by the VMThread");
2295 // get OutOfMemoryError zero-parameter constructor
2296 InstanceKlass* oome_ik = vmClasses::OutOfMemoryError_klass();
2297 _oome_constructor = oome_ik->find_method(vmSymbols::object_initializer_name(),
2298 vmSymbols::void_method_signature());
2299 // get thread throwing OOME when generating the heap dump at OOME
2300 _oome_thread = JavaThread::current();
2301 } else {
2302 _oome_thread = nullptr;
2303 _oome_constructor = nullptr;
2304 }
2305 }
2306
2307 ~VM_HeapDumper() {
2308 if (_thread_dumpers != nullptr) {
2309 for (int i = 0; i < _thread_dumpers_count; i++) {
2310 delete _thread_dumpers[i];
2311 }
2312 FREE_C_HEAP_ARRAY(ThreadDumper*, _thread_dumpers);
2313 }
2314
2315 if (_dumper_controller != nullptr) {
2316 delete _dumper_controller;
2317 _dumper_controller = nullptr;
2318 }
2319 delete _klass_map;
2320 }
2321 int dump_seq() { return _dump_seq; }
2322 bool is_parallel_dump() { return _num_dumper_threads > 1; }
2323 void prepare_parallel_dump(WorkerThreads* workers);
2324
2325 VMOp_Type type() const { return VMOp_HeapDumper; }
2326 virtual bool doit_prologue();
2327 void doit();
2328 void work(uint worker_id);
2329
2330 // UnmountedVThreadDumper implementation
2331 void dump_vthread(oop vt, AbstractDumpWriter* segment_writer);
2332 };
2333
2334 bool VM_HeapDumper::skip_operation() const {
2335 return false;
2336 }
2337
2338 // fixes up the current dump record and writes HPROF_HEAP_DUMP_END record
2339 void DumperSupport::end_of_dump(AbstractDumpWriter* writer) {
2340 writer->finish_dump_segment();
2341
2342 writer->write_u1(HPROF_HEAP_DUMP_END);
2343 writer->write_u4(0);
2344 writer->write_u4(0);
2345 }
2346
2347 // Write a HPROF_GC_ROOT_THREAD_OBJ record for platform/carrier and mounted virtual threads.
2348 // Then walk the stack so that locals and JNI locals are dumped.
2349 void VM_HeapDumper::dump_threads(AbstractDumpWriter* writer) {
2350 for (int i = 0; i < _thread_dumpers_count; i++) {
2351 _thread_dumpers[i]->dump_thread_obj(writer);
2352 _thread_dumpers[i]->dump_stack_refs(writer);
2353 }
2354 }
2355
2356 bool VM_HeapDumper::doit_prologue() {
2357 if (_gc_before_heap_dump && (UseZGC || UseShenandoahGC)) {
2358 // ZGC and Shenandoah cannot perform a synchronous GC cycle from within the VM thread.
2359 // So collect_as_vm_thread() is a noop. To respect the _gc_before_heap_dump flag a
2360 // synchronous GC cycle is performed from the caller thread in the prologue.
2361 Universe::heap()->collect(GCCause::_heap_dump);
2362 }
2363 return VM_GC_Operation::doit_prologue();
2364 }
2365
2366 void VM_HeapDumper::prepare_parallel_dump(WorkerThreads* workers) {
2367 uint num_active_workers = workers != nullptr ? workers->active_workers() : 0;
2368 uint num_requested_dump_threads = _num_dumper_threads;
2369 // check if we can dump in parallel based on requested and active threads
2370 if (num_active_workers <= 1 || num_requested_dump_threads <= 1) {
2371 _num_dumper_threads = 1;
2372 } else {
2373 _num_dumper_threads = clamp(num_requested_dump_threads, 2U, num_active_workers);
2374 }
2375 _dumper_controller = new (std::nothrow) DumperController(_num_dumper_threads);
2376 bool can_parallel = _num_dumper_threads > 1;
2377 log_info(heapdump)("Requested dump threads %u, active dump threads %u, "
2378 "actual dump threads %u, parallelism %s",
2379 num_requested_dump_threads, num_active_workers,
2380 _num_dumper_threads, can_parallel ? "true" : "false");
2381 }
2382
2383 // The VM operation that dumps the heap. The dump consists of the following
2384 // records:
2385 //
2386 // HPROF_HEADER
2387 // [HPROF_UTF8]*
2388 // [HPROF_LOAD_CLASS]*
2389 // [[HPROF_FRAME]*|HPROF_TRACE]*
2390 // [HPROF_GC_CLASS_DUMP]*
2391 // [HPROF_HEAP_DUMP_SEGMENT]*
2392 // HPROF_HEAP_DUMP_END
2393 //
2394 // The HPROF_TRACE records represent the stack traces where the heap dump
2395 // is generated and a "dummy trace" record which does not include
2396 // any frames. The dummy trace record is used to be referenced as the
2397 // unknown object alloc site.
2398 //
2399 // Each HPROF_HEAP_DUMP_SEGMENT record has a length followed by sub-records.
2400 // To allow the heap dump be generated in a single pass we remember the position
2401 // of the dump length and fix it up after all sub-records have been written.
2402 // To generate the sub-records we iterate over the heap, writing
2403 // HPROF_GC_INSTANCE_DUMP, HPROF_GC_OBJ_ARRAY_DUMP, and HPROF_GC_PRIM_ARRAY_DUMP
2404 // records as we go. Once that is done we write records for some of the GC
2405 // roots.
2406
2407 void VM_HeapDumper::doit() {
2408
2409 CollectedHeap* ch = Universe::heap();
2410
2411 ch->ensure_parsability(false); // must happen, even if collection does
2412 // not happen (e.g. due to GCLocker)
2413
2414 if (_gc_before_heap_dump) {
2415 if (GCLocker::is_active()) {
2416 warning("GC locker is held; pre-heapdump GC was skipped");
2417 } else {
2418 ch->collect_as_vm_thread(GCCause::_heap_dump);
2419 }
2420 }
2421
2422 WorkerThreads* workers = ch->safepoint_workers();
2423 prepare_parallel_dump(workers);
2424
2425 if (!is_parallel_dump()) {
2426 work(VMDumperId);
2427 } else {
2428 ParallelObjectIterator poi(_num_dumper_threads);
2429 _poi = &poi;
2430 workers->run_task(this, _num_dumper_threads);
2431 _poi = nullptr;
2432 }
2433 }
2434
2435 void VM_HeapDumper::work(uint worker_id) {
2436 // VM Dumper works on all non-heap data dumping and part of heap iteration.
2437 int dumper_id = get_next_dumper_id();
2438
2439 if (is_vm_dumper(dumper_id)) {
2440 // lock global writer, it will be unlocked after VM Dumper finishes with non-heap data
2441 _dumper_controller->lock_global_writer();
2442 _dumper_controller->signal_start();
2443 } else {
2444 _dumper_controller->wait_for_start_signal();
2445 }
2446
2447 if (is_vm_dumper(dumper_id)) {
2448 TraceTime timer("Dump non-objects", TRACETIME_LOG(Info, heapdump));
2449 // Write the file header - we always use 1.0.2
2450 const char* header = "JAVA PROFILE 1.0.2";
2451
2452 // header is few bytes long - no chance to overflow int
2453 writer()->write_raw(header, strlen(header) + 1); // NUL terminated
2454 writer()->write_u4(oopSize);
2455 // timestamp is current time in ms
2456 writer()->write_u8(os::javaTimeMillis());
2457 // HPROF_UTF8 records
2458 SymbolTableDumper sym_dumper(writer());
2459 SymbolTable::symbols_do(&sym_dumper);
2460
2461 // write HPROF_LOAD_CLASS records
2462 {
2463 LoadedClassDumper loaded_class_dumper(writer(), _klass_map);
2464 ClassLoaderDataGraph::classes_do(&loaded_class_dumper);
2465 }
2466
2467 // write HPROF_FRAME and HPROF_TRACE records
2468 // this must be called after _klass_map is built when iterating the classes above.
2469 dump_stack_traces(writer());
2470
2471 // unlock global writer, so parallel dumpers can dump stack traces of unmounted virtual threads
2472 _dumper_controller->unlock_global_writer();
2473 }
2474
2475 // HPROF_HEAP_DUMP/HPROF_HEAP_DUMP_SEGMENT starts here
2476
2477 ResourceMark rm;
2478 // share global compressor, local DumpWriter is not responsible for its life cycle
2479 DumpWriter segment_writer(DumpMerger::get_writer_path(writer()->get_file_path(), dumper_id),
2480 writer()->is_overwrite(), writer()->compressor());
2481 if (!segment_writer.has_error()) {
2482 if (is_vm_dumper(dumper_id)) {
2483 // dump some non-heap subrecords to heap dump segment
2484 TraceTime timer("Dump non-objects (part 2)", TRACETIME_LOG(Info, heapdump));
2485 // Writes HPROF_GC_CLASS_DUMP records
2486 ClassDumper class_dumper(&segment_writer);
2487 ClassLoaderDataGraph::classes_do(&class_dumper);
2488
2489 // HPROF_GC_ROOT_THREAD_OBJ + frames + jni locals
2490 dump_threads(&segment_writer);
2491
2492 // HPROF_GC_ROOT_JNI_GLOBAL
2493 JNIGlobalsDumper jni_dumper(&segment_writer);
2494 JNIHandles::oops_do(&jni_dumper);
2495 // technically not jni roots, but global roots
2496 // for things like preallocated throwable backtraces
2497 Universe::vm_global()->oops_do(&jni_dumper);
2498 // HPROF_GC_ROOT_STICKY_CLASS
2499 // These should be classes in the null class loader data, and not all classes
2500 // if !ClassUnloading
2501 StickyClassDumper stiky_class_dumper(&segment_writer);
2502 ClassLoaderData::the_null_class_loader_data()->classes_do(&stiky_class_dumper);
2503 }
2504
2505 // Heap iteration.
2506 // writes HPROF_GC_INSTANCE_DUMP records.
2507 // After each sub-record is written check_segment_length will be invoked
2508 // to check if the current segment exceeds a threshold. If so, a new
2509 // segment is started.
2510 // The HPROF_GC_CLASS_DUMP and HPROF_GC_INSTANCE_DUMP are the vast bulk
2511 // of the heap dump.
2512
2513 TraceTime timer(is_parallel_dump() ? "Dump heap objects in parallel" : "Dump heap objects", TRACETIME_LOG(Info, heapdump));
2514 HeapObjectDumper obj_dumper(&segment_writer, this);
2515 if (!is_parallel_dump()) {
2516 Universe::heap()->object_iterate(&obj_dumper);
2517 } else {
2518 // == Parallel dump
2519 _poi->object_iterate(&obj_dumper, worker_id);
2520 }
2521
2522 segment_writer.finish_dump_segment();
2523 segment_writer.flush();
2524 }
2525
2526 _dumper_controller->dumper_complete(&segment_writer, writer());
2527
2528 if (is_vm_dumper(dumper_id)) {
2529 _dumper_controller->wait_all_dumpers_complete();
2530
2531 // flush global writer
2532 writer()->flush();
2533
2534 // At this point, all fragments of the heapdump have been written to separate files.
2535 // We need to merge them into a complete heapdump and write HPROF_HEAP_DUMP_END at that time.
2536 }
2537 }
2538
2539 void VM_HeapDumper::dump_stack_traces(AbstractDumpWriter* writer) {
2540 // write a HPROF_TRACE record without any frames to be referenced as object alloc sites
2541 DumperSupport::write_header(writer, HPROF_TRACE, 3 * sizeof(u4));
2542 writer->write_u4((u4)STACK_TRACE_ID);
2543 writer->write_u4(0); // thread number
2544 writer->write_u4(0); // frame count
2545
2546 // max number if every platform thread is carrier with mounted virtual thread
2547 _thread_dumpers = NEW_C_HEAP_ARRAY(ThreadDumper*, Threads::number_of_threads() * 2, mtInternal);
2548
2549 for (JavaThreadIteratorWithHandle jtiwh; JavaThread * thread = jtiwh.next(); ) {
2550 if (ThreadDumper::should_dump_pthread(thread)) {
2551 bool add_oom_frame = is_oom_thread(thread);
2552
2553 oop mounted_vt = thread->is_vthread_mounted() ? thread->vthread() : nullptr;
2554 if (mounted_vt != nullptr && !ThreadDumper::should_dump_vthread(mounted_vt)) {
2555 mounted_vt = nullptr;
2556 }
2557
2558 // mounted vthread (if any)
2559 if (mounted_vt != nullptr) {
2560 ThreadDumper* thread_dumper = new ThreadDumper(ThreadDumper::ThreadType::MountedVirtual, thread, mounted_vt);
2561 _thread_dumpers[_thread_dumpers_count++] = thread_dumper;
2562 if (add_oom_frame) {
2563 thread_dumper->add_oom_frame(_oome_constructor);
2564 // we add oom frame to the VT stack, don't add it to the carrier thread stack
2565 add_oom_frame = false;
2566 }
2567 thread_dumper->init_serial_nums(&_thread_serial_num, &_frame_serial_num);
2568 thread_dumper->dump_stack_traces(writer, _klass_map);
2569 }
2570
2571 // platform or carrier thread
2572 ThreadDumper* thread_dumper = new ThreadDumper(ThreadDumper::ThreadType::Platform, thread, thread->threadObj());
2573 _thread_dumpers[_thread_dumpers_count++] = thread_dumper;
2574 if (add_oom_frame) {
2575 thread_dumper->add_oom_frame(_oome_constructor);
2576 }
2577 thread_dumper->init_serial_nums(&_thread_serial_num, &_frame_serial_num);
2578 thread_dumper->dump_stack_traces(writer, _klass_map);
2579 }
2580 }
2581 }
2582
2583 void VM_HeapDumper::dump_vthread(oop vt, AbstractDumpWriter* segment_writer) {
2584 // unmounted vthread has no JavaThread
2585 ThreadDumper thread_dumper(ThreadDumper::ThreadType::UnmountedVirtual, nullptr, vt);
2586 thread_dumper.init_serial_nums(&_thread_serial_num, &_frame_serial_num);
2587
2588 // write HPROF_TRACE/HPROF_FRAME records to global writer
2589 _dumper_controller->lock_global_writer();
2590 thread_dumper.dump_stack_traces(writer(), _klass_map);
2591 _dumper_controller->unlock_global_writer();
2592
2593 // write HPROF_GC_ROOT_THREAD_OBJ/HPROF_GC_ROOT_JAVA_FRAME/HPROF_GC_ROOT_JNI_LOCAL subrecord
2594 // to segment writer
2595 thread_dumper.dump_thread_obj(segment_writer);
2596 thread_dumper.dump_stack_refs(segment_writer);
2597 }
2598
2599 // dump the heap to given path.
2600 int HeapDumper::dump(const char* path, outputStream* out, int compression, bool overwrite, uint num_dump_threads) {
2601 assert(path != nullptr && strlen(path) > 0, "path missing");
2602
2603 // print message in interactive case
2604 if (out != nullptr) {
2605 out->print_cr("Dumping heap to %s ...", path);
2606 timer()->start();
2607 }
2608
2609 if (_oome && num_dump_threads > 1) {
2610 // Each additional parallel writer requires several MB of internal memory
2611 // (DumpWriter buffer, DumperClassCacheTable, GZipCompressor buffers).
2612 // For the OOM handling we may already be limited in memory.
2613 // Lets ensure we have at least 20MB per thread.
2614 julong max_threads = os::free_memory() / (20 * M);
2615 if (num_dump_threads > max_threads) {
2616 num_dump_threads = MAX2<uint>(1, (uint)max_threads);
2617 }
2618 }
2619
2620 // create JFR event
2621 EventHeapDump event;
2622
2623 AbstractCompressor* compressor = nullptr;
2624
2625 if (compression > 0) {
2626 compressor = new (std::nothrow) GZipCompressor(compression);
2627
2628 if (compressor == nullptr) {
2629 set_error("Could not allocate gzip compressor");
2630 return -1;
2631 }
2632 }
2633
2634 DumpWriter writer(path, overwrite, compressor);
2635
2636 if (writer.error() != nullptr) {
2637 set_error(writer.error());
2638 if (out != nullptr) {
2639 out->print_cr("Unable to create %s: %s", path,
2640 (error() != nullptr) ? error() : "reason unknown");
2641 }
2642 return -1;
2643 }
2644
2645 // generate the segmented heap dump into separate files
2646 VM_HeapDumper dumper(&writer, _gc_before_heap_dump, _oome, num_dump_threads);
2647 VMThread::execute(&dumper);
2648
2649 // record any error that the writer may have encountered
2650 set_error(writer.error());
2651
2652 // Heap dump process is done in two phases
2653 //
2654 // Phase 1: Concurrent threads directly write heap data to multiple heap files.
2655 // This is done by VM_HeapDumper, which is performed within safepoint.
2656 //
2657 // Phase 2: Merge multiple heap files into one complete heap dump file.
2658 // This is done by DumpMerger, which is performed outside safepoint
2659
2660 DumpMerger merger(path, &writer, dumper.dump_seq());
2661 // Perform heapdump file merge operation in the current thread prevents us
2662 // from occupying the VM Thread, which in turn affects the occurrence of
2663 // GC and other VM operations.
2664 merger.do_merge();
2665 if (writer.error() != nullptr) {
2666 set_error(writer.error());
2667 }
2668
2669 // emit JFR event
2670 if (error() == nullptr) {
2671 event.set_destination(path);
2672 event.set_gcBeforeDump(_gc_before_heap_dump);
2673 event.set_size(writer.bytes_written());
2674 event.set_onOutOfMemoryError(_oome);
2675 event.set_overwrite(overwrite);
2676 event.set_compression(compression);
2677 event.commit();
2678 } else {
2679 log_debug(cds, heap)("Error %s while dumping heap", error());
2680 }
2681
2682 // print message in interactive case
2683 if (out != nullptr) {
2684 timer()->stop();
2685 if (error() == nullptr) {
2686 out->print_cr("Heap dump file created [" JULONG_FORMAT " bytes in %3.3f secs]",
2687 writer.bytes_written(), timer()->seconds());
2688 } else {
2689 out->print_cr("Dump file is incomplete: %s", writer.error());
2690 }
2691 }
2692
2693 if (compressor != nullptr) {
2694 delete compressor;
2695 }
2696 return (writer.error() == nullptr) ? 0 : -1;
2697 }
2698
2699 // stop timer (if still active), and free any error string we might be holding
2700 HeapDumper::~HeapDumper() {
2701 if (timer()->is_active()) {
2702 timer()->stop();
2703 }
2704 set_error(nullptr);
2705 }
2706
2707
2708 // returns the error string (resource allocated), or null
2709 char* HeapDumper::error_as_C_string() const {
2710 if (error() != nullptr) {
2711 char* str = NEW_RESOURCE_ARRAY(char, strlen(error())+1);
2712 strcpy(str, error());
2713 return str;
2714 } else {
2715 return nullptr;
2716 }
2717 }
2718
2719 // set the error string
2720 void HeapDumper::set_error(char const* error) {
2721 if (_error != nullptr) {
2722 os::free(_error);
2723 }
2724 if (error == nullptr) {
2725 _error = nullptr;
2726 } else {
2727 _error = os::strdup(error);
2728 assert(_error != nullptr, "allocation failure");
2729 }
2730 }
2731
2732 // Called by out-of-memory error reporting by a single Java thread
2733 // outside of a JVM safepoint
2734 void HeapDumper::dump_heap_from_oome() {
2735 HeapDumper::dump_heap(true);
2736 }
2737
2738 // Called by error reporting by a single Java thread outside of a JVM safepoint,
2739 // or by heap dumping by the VM thread during a (GC) safepoint. Thus, these various
2740 // callers are strictly serialized and guaranteed not to interfere below. For more
2741 // general use, however, this method will need modification to prevent
2742 // inteference when updating the static variables base_path and dump_file_seq below.
2743 void HeapDumper::dump_heap() {
2744 HeapDumper::dump_heap(false);
2745 }
2746
2747 void HeapDumper::dump_heap(bool oome) {
2748 static char base_path[JVM_MAXPATHLEN] = {'\0'};
2749 static uint dump_file_seq = 0;
2750 char* my_path;
2751 const int max_digit_chars = 20;
2752
2753 const char* dump_file_name = "java_pid";
2754 const char* dump_file_ext = HeapDumpGzipLevel > 0 ? ".hprof.gz" : ".hprof";
2755
2756 // The dump file defaults to java_pid<pid>.hprof in the current working
2757 // directory. HeapDumpPath=<file> can be used to specify an alternative
2758 // dump file name or a directory where dump file is created.
2759 if (dump_file_seq == 0) { // first time in, we initialize base_path
2760 // Calculate potentially longest base path and check if we have enough
2761 // allocated statically.
2762 const size_t total_length =
2763 (HeapDumpPath == nullptr ? 0 : strlen(HeapDumpPath)) +
2764 strlen(os::file_separator()) + max_digit_chars +
2765 strlen(dump_file_name) + strlen(dump_file_ext) + 1;
2766 if (total_length > sizeof(base_path)) {
2767 warning("Cannot create heap dump file. HeapDumpPath is too long.");
2768 return;
2769 }
2770
2771 bool use_default_filename = true;
2772 if (HeapDumpPath == nullptr || HeapDumpPath[0] == '\0') {
2773 // HeapDumpPath=<file> not specified
2774 } else {
2775 strcpy(base_path, HeapDumpPath);
2776 // check if the path is a directory (must exist)
2777 DIR* dir = os::opendir(base_path);
2778 if (dir == nullptr) {
2779 use_default_filename = false;
2780 } else {
2781 // HeapDumpPath specified a directory. We append a file separator
2782 // (if needed).
2783 os::closedir(dir);
2784 size_t fs_len = strlen(os::file_separator());
2785 if (strlen(base_path) >= fs_len) {
2786 char* end = base_path;
2787 end += (strlen(base_path) - fs_len);
2788 if (strcmp(end, os::file_separator()) != 0) {
2789 strcat(base_path, os::file_separator());
2790 }
2791 }
2792 }
2793 }
2794 // If HeapDumpPath wasn't a file name then we append the default name
2795 if (use_default_filename) {
2796 const size_t dlen = strlen(base_path); // if heap dump dir specified
2797 jio_snprintf(&base_path[dlen], sizeof(base_path)-dlen, "%s%d%s",
2798 dump_file_name, os::current_process_id(), dump_file_ext);
2799 }
2800 const size_t len = strlen(base_path) + 1;
2801 my_path = (char*)os::malloc(len, mtInternal);
2802 if (my_path == nullptr) {
2803 warning("Cannot create heap dump file. Out of system memory.");
2804 return;
2805 }
2806 strncpy(my_path, base_path, len);
2807 } else {
2808 // Append a sequence number id for dumps following the first
2809 const size_t len = strlen(base_path) + max_digit_chars + 2; // for '.' and \0
2810 my_path = (char*)os::malloc(len, mtInternal);
2811 if (my_path == nullptr) {
2812 warning("Cannot create heap dump file. Out of system memory.");
2813 return;
2814 }
2815 jio_snprintf(my_path, len, "%s.%d", base_path, dump_file_seq);
2816 }
2817 dump_file_seq++; // increment seq number for next time we dump
2818
2819 HeapDumper dumper(false /* no GC before heap dump */,
2820 oome /* pass along out-of-memory-error flag */);
2821 dumper.dump(my_path, tty, HeapDumpGzipLevel);
2822 os::free(my_path);
2823 }