1 /*
2 * Copyright (c) 2005, 2023, 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 "precompiled.hpp"
27 #include "classfile/classLoaderData.inline.hpp"
28 #include "classfile/classLoaderDataGraph.hpp"
29 #include "classfile/javaClasses.inline.hpp"
30 #include "classfile/symbolTable.hpp"
31 #include "classfile/vmClasses.hpp"
32 #include "classfile/vmSymbols.hpp"
33 #include "gc/shared/gcLocker.hpp"
34 #include "gc/shared/gcVMOperations.hpp"
35 #include "gc/shared/workerThread.hpp"
36 #include "jfr/jfrEvents.hpp"
37 #include "jvm.h"
38 #include "memory/allocation.inline.hpp"
39 #include "memory/resourceArea.hpp"
40 #include "memory/universe.hpp"
41 #include "oops/fieldStreams.inline.hpp"
42 #include "oops/klass.inline.hpp"
43 #include "oops/objArrayKlass.hpp"
44 #include "oops/objArrayOop.inline.hpp"
45 #include "oops/oop.inline.hpp"
46 #include "oops/typeArrayOop.inline.hpp"
47 #include "runtime/continuationWrapper.inline.hpp"
48 #include "runtime/frame.inline.hpp"
49 #include "runtime/handles.inline.hpp"
50 #include "runtime/javaCalls.hpp"
51 #include "runtime/javaThread.inline.hpp"
52 #include "runtime/jniHandles.hpp"
53 #include "runtime/os.hpp"
54 #include "runtime/threads.hpp"
55 #include "runtime/threadSMR.hpp"
56 #include "runtime/vframe.hpp"
57 #include "runtime/vmOperations.hpp"
58 #include "runtime/vmThread.hpp"
59 #include "runtime/timerTrace.hpp"
60 #include "services/heapDumper.hpp"
61 #include "services/heapDumperCompression.hpp"
62 #include "services/threadService.hpp"
63 #include "utilities/checkedCast.hpp"
64 #include "utilities/macros.hpp"
65 #include "utilities/ostream.hpp"
66 #ifdef LINUX
67 #include "os_linux.hpp"
68 #endif
69
70 /*
71 * HPROF binary format - description copied from:
72 * src/share/demo/jvmti/hprof/hprof_io.c
73 *
74 *
75 * header "JAVA PROFILE 1.0.2" (0-terminated)
76 *
77 * u4 size of identifiers. Identifiers are used to represent
78 * UTF8 strings, objects, stack traces, etc. They usually
79 * have the same size as host pointers.
80 * u4 high word
81 * u4 low word number of milliseconds since 0:00 GMT, 1/1/70
82 * [record]* a sequence of records.
83 *
84 *
85 * Record format:
86 *
87 * u1 a TAG denoting the type of the record
88 * u4 number of *microseconds* since the time stamp in the
89 * header. (wraps around in a little more than an hour)
90 * u4 number of bytes *remaining* in the record. Note that
91 * this number excludes the tag and the length field itself.
92 * [u1]* BODY of the record (a sequence of bytes)
93 *
94 *
95 * The following TAGs are supported:
96 *
97 * TAG BODY notes
98 *----------------------------------------------------------
99 * HPROF_UTF8 a UTF8-encoded name
100 *
101 * id name ID
102 * [u1]* UTF8 characters (no trailing zero)
103 *
104 * HPROF_LOAD_CLASS a newly loaded class
105 *
106 * u4 class serial number (> 0)
107 * id class object ID
108 * u4 stack trace serial number
109 * id class name ID
110 *
111 * HPROF_UNLOAD_CLASS an unloading class
112 *
113 * u4 class serial_number
114 *
115 * HPROF_FRAME a Java stack frame
116 *
117 * id stack frame ID
118 * id method name ID
119 * id method signature ID
120 * id source file name ID
121 * u4 class serial number
122 * i4 line number. >0: normal
123 * -1: unknown
124 * -2: compiled method
125 * -3: native method
126 *
127 * HPROF_TRACE a Java stack trace
128 *
129 * u4 stack trace serial number
130 * u4 thread serial number
131 * u4 number of frames
132 * [id]* stack frame IDs
133 *
134 *
135 * HPROF_ALLOC_SITES a set of heap allocation sites, obtained after GC
136 *
137 * u2 flags 0x0001: incremental vs. complete
138 * 0x0002: sorted by allocation vs. live
139 * 0x0004: whether to force a GC
140 * u4 cutoff ratio
141 * u4 total live bytes
142 * u4 total live instances
143 * u8 total bytes allocated
144 * u8 total instances allocated
145 * u4 number of sites that follow
146 * [u1 is_array: 0: normal object
147 * 2: object array
148 * 4: boolean array
149 * 5: char array
150 * 6: float array
151 * 7: double array
152 * 8: byte array
153 * 9: short array
154 * 10: int array
155 * 11: long array
156 * u4 class serial number (may be zero during startup)
157 * u4 stack trace serial number
158 * u4 number of bytes alive
159 * u4 number of instances alive
160 * u4 number of bytes allocated
161 * u4]* number of instance allocated
162 *
163 * HPROF_START_THREAD a newly started thread.
164 *
165 * u4 thread serial number (> 0)
166 * id thread object ID
167 * u4 stack trace serial number
168 * id thread name ID
169 * id thread group name ID
170 * id thread group parent name ID
171 *
172 * HPROF_END_THREAD a terminating thread.
173 *
174 * u4 thread serial number
175 *
176 * HPROF_HEAP_SUMMARY heap summary
177 *
178 * u4 total live bytes
179 * u4 total live instances
180 * u8 total bytes allocated
181 * u8 total instances allocated
182 *
183 * HPROF_HEAP_DUMP denote a heap dump
184 *
185 * [heap dump sub-records]*
186 *
187 * There are four kinds of heap dump sub-records:
188 *
189 * u1 sub-record type
190 *
191 * HPROF_GC_ROOT_UNKNOWN unknown root
192 *
193 * id object ID
194 *
195 * HPROF_GC_ROOT_THREAD_OBJ thread object
196 *
197 * id thread object ID (may be 0 for a
198 * thread newly attached through JNI)
199 * u4 thread sequence number
200 * u4 stack trace sequence number
201 *
202 * HPROF_GC_ROOT_JNI_GLOBAL JNI global ref root
203 *
204 * id object ID
205 * id JNI global ref ID
206 *
207 * HPROF_GC_ROOT_JNI_LOCAL JNI local ref
208 *
209 * id object ID
210 * u4 thread serial number
211 * u4 frame # in stack trace (-1 for empty)
212 *
213 * HPROF_GC_ROOT_JAVA_FRAME Java stack frame
214 *
215 * id object ID
216 * u4 thread serial number
217 * u4 frame # in stack trace (-1 for empty)
218 *
219 * HPROF_GC_ROOT_NATIVE_STACK Native stack
220 *
221 * id object ID
222 * u4 thread serial number
223 *
224 * HPROF_GC_ROOT_STICKY_CLASS System class
225 *
226 * id object ID
227 *
228 * HPROF_GC_ROOT_THREAD_BLOCK Reference from thread block
229 *
230 * id object ID
231 * u4 thread serial number
232 *
233 * HPROF_GC_ROOT_MONITOR_USED Busy monitor
234 *
235 * id object ID
236 *
237 * HPROF_GC_CLASS_DUMP dump of a class object
238 *
239 * id class object ID
240 * u4 stack trace serial number
241 * id super class object ID
242 * id class loader object ID
243 * id signers object ID
244 * id protection domain object ID
245 * id reserved
246 * id reserved
247 *
248 * u4 instance size (in bytes)
249 *
250 * u2 size of constant pool
251 * [u2, constant pool index,
252 * ty, type
253 * 2: object
254 * 4: boolean
255 * 5: char
256 * 6: float
257 * 7: double
258 * 8: byte
259 * 9: short
260 * 10: int
261 * 11: long
262 * vl]* and value
263 *
264 * u2 number of static fields
265 * [id, static field name,
266 * ty, type,
267 * vl]* and value
268 *
269 * u2 number of inst. fields (not inc. super)
270 * [id, instance field name,
271 * ty]* type
272 *
273 * HPROF_GC_INSTANCE_DUMP dump of a normal object
274 *
275 * id object ID
276 * u4 stack trace serial number
277 * id class object ID
278 * u4 number of bytes that follow
279 * [vl]* instance field values (class, followed
280 * by super, super's super ...)
281 *
282 * HPROF_GC_OBJ_ARRAY_DUMP dump of an object array
283 *
284 * id array object ID
285 * u4 stack trace serial number
286 * u4 number of elements
287 * id array class ID
288 * [id]* elements
289 *
290 * HPROF_GC_PRIM_ARRAY_DUMP dump of a primitive array
291 *
292 * id array object ID
293 * u4 stack trace serial number
294 * u4 number of elements
295 * u1 element type
296 * 4: boolean array
297 * 5: char array
298 * 6: float array
299 * 7: double array
300 * 8: byte array
301 * 9: short array
302 * 10: int array
303 * 11: long array
304 * [u1]* elements
305 *
306 * HPROF_CPU_SAMPLES a set of sample traces of running threads
307 *
308 * u4 total number of samples
309 * u4 # of traces
310 * [u4 # of samples
311 * u4]* stack trace serial number
312 *
313 * HPROF_CONTROL_SETTINGS the settings of on/off switches
314 *
315 * u4 0x00000001: alloc traces on/off
316 * 0x00000002: cpu sampling on/off
317 * u2 stack trace depth
318 *
319 *
320 * When the header is "JAVA PROFILE 1.0.2" a heap dump can optionally
321 * be generated as a sequence of heap dump segments. This sequence is
322 * terminated by an end record. The additional tags allowed by format
323 * "JAVA PROFILE 1.0.2" are:
324 *
325 * HPROF_HEAP_DUMP_SEGMENT denote a heap dump segment
326 *
327 * [heap dump sub-records]*
328 * The same sub-record types allowed by HPROF_HEAP_DUMP
329 *
330 * HPROF_HEAP_DUMP_END denotes the end of a heap dump
331 *
332 */
333
334
335 // HPROF tags
336
337 enum hprofTag : u1 {
338 // top-level records
339 HPROF_UTF8 = 0x01,
340 HPROF_LOAD_CLASS = 0x02,
341 HPROF_UNLOAD_CLASS = 0x03,
342 HPROF_FRAME = 0x04,
343 HPROF_TRACE = 0x05,
344 HPROF_ALLOC_SITES = 0x06,
345 HPROF_HEAP_SUMMARY = 0x07,
346 HPROF_START_THREAD = 0x0A,
347 HPROF_END_THREAD = 0x0B,
348 HPROF_HEAP_DUMP = 0x0C,
349 HPROF_CPU_SAMPLES = 0x0D,
350 HPROF_CONTROL_SETTINGS = 0x0E,
351
352 // 1.0.2 record types
353 HPROF_HEAP_DUMP_SEGMENT = 0x1C,
354 HPROF_HEAP_DUMP_END = 0x2C,
355
356 // field types
357 HPROF_ARRAY_OBJECT = 0x01,
358 HPROF_NORMAL_OBJECT = 0x02,
359 HPROF_BOOLEAN = 0x04,
360 HPROF_CHAR = 0x05,
361 HPROF_FLOAT = 0x06,
362 HPROF_DOUBLE = 0x07,
363 HPROF_BYTE = 0x08,
364 HPROF_SHORT = 0x09,
365 HPROF_INT = 0x0A,
366 HPROF_LONG = 0x0B,
367
368 // data-dump sub-records
369 HPROF_GC_ROOT_UNKNOWN = 0xFF,
370 HPROF_GC_ROOT_JNI_GLOBAL = 0x01,
371 HPROF_GC_ROOT_JNI_LOCAL = 0x02,
372 HPROF_GC_ROOT_JAVA_FRAME = 0x03,
373 HPROF_GC_ROOT_NATIVE_STACK = 0x04,
374 HPROF_GC_ROOT_STICKY_CLASS = 0x05,
375 HPROF_GC_ROOT_THREAD_BLOCK = 0x06,
376 HPROF_GC_ROOT_MONITOR_USED = 0x07,
377 HPROF_GC_ROOT_THREAD_OBJ = 0x08,
378 HPROF_GC_CLASS_DUMP = 0x20,
379 HPROF_GC_INSTANCE_DUMP = 0x21,
380 HPROF_GC_OBJ_ARRAY_DUMP = 0x22,
381 HPROF_GC_PRIM_ARRAY_DUMP = 0x23
382 };
383
384 // Default stack trace ID (used for dummy HPROF_TRACE record)
385 enum {
386 STACK_TRACE_ID = 1,
387 INITIAL_CLASS_COUNT = 200
388 };
389
390 // Supports I/O operations for a dump
391 // Base class for dump and parallel dump
392 class AbstractDumpWriter : public CHeapObj<mtInternal> {
393 protected:
394 enum {
395 io_buffer_max_size = 1*M,
396 dump_segment_header_size = 9
397 };
398
399 char* _buffer; // internal buffer
400 size_t _size;
401 size_t _pos;
402
403 bool _in_dump_segment; // Are we currently in a dump segment?
404 bool _is_huge_sub_record; // Are we writing a sub-record larger than the buffer size?
405 DEBUG_ONLY(size_t _sub_record_left;) // The bytes not written for the current sub-record.
406 DEBUG_ONLY(bool _sub_record_ended;) // True if we have called the end_sub_record().
407
408 char* buffer() const { return _buffer; }
409 size_t buffer_size() const { return _size; }
410 void set_position(size_t pos) { _pos = pos; }
411
412 // Can be called if we have enough room in the buffer.
413 void write_fast(const void* s, size_t len);
414
415 // Returns true if we have enough room in the buffer for 'len' bytes.
416 bool can_write_fast(size_t len);
417
418 void write_address(address a);
419
420 public:
421 AbstractDumpWriter() :
422 _buffer(nullptr),
423 _size(io_buffer_max_size),
424 _pos(0),
425 _in_dump_segment(false) { }
426
427 // Total number of bytes written to the disk
428 virtual julong bytes_written() const = 0;
429 // Return non-null if error occurred
430 virtual char const* error() const = 0;
431
432 size_t position() const { return _pos; }
433 // writer functions
434 virtual void write_raw(const void* s, size_t len);
435 void write_u1(u1 x);
436 void write_u2(u2 x);
437 void write_u4(u4 x);
438 void write_u8(u8 x);
439 void write_objectID(oop o);
440 void write_rootID(oop* p);
441 void write_symbolID(Symbol* o);
442 void write_classID(Klass* k);
443 void write_id(u4 x);
444
445 // Start a new sub-record. Starts a new heap dump segment if needed.
446 void start_sub_record(u1 tag, u4 len);
447 // Ends the current sub-record.
448 void end_sub_record();
449 // Finishes the current dump segment if not already finished.
450 void finish_dump_segment();
451 // Flush internal buffer to persistent storage
452 virtual void flush() = 0;
453 };
454
455 void AbstractDumpWriter::write_fast(const void* s, size_t len) {
456 assert(!_in_dump_segment || (_sub_record_left >= len), "sub-record too large");
457 assert(buffer_size() - position() >= len, "Must fit");
458 debug_only(_sub_record_left -= len);
459 memcpy(buffer() + position(), s, len);
460 set_position(position() + len);
461 }
462
463 bool AbstractDumpWriter::can_write_fast(size_t len) {
464 return buffer_size() - position() >= len;
465 }
466
467 // write raw bytes
468 void AbstractDumpWriter::write_raw(const void* s, size_t len) {
469 assert(!_in_dump_segment || (_sub_record_left >= len), "sub-record too large");
470 debug_only(_sub_record_left -= len);
471
472 // flush buffer to make room.
473 while (len > buffer_size() - position()) {
474 assert(!_in_dump_segment || _is_huge_sub_record,
475 "Cannot overflow in non-huge sub-record.");
476 size_t to_write = buffer_size() - position();
477 memcpy(buffer() + position(), s, to_write);
478 s = (void*) ((char*) s + to_write);
479 len -= to_write;
480 set_position(position() + to_write);
481 flush();
482 }
483
484 memcpy(buffer() + position(), s, len);
485 set_position(position() + len);
486 }
487
488 // Makes sure we inline the fast write into the write_u* functions. This is a big speedup.
489 #define WRITE_KNOWN_TYPE(p, len) do { if (can_write_fast((len))) write_fast((p), (len)); \
490 else write_raw((p), (len)); } while (0)
491
492 void AbstractDumpWriter::write_u1(u1 x) {
493 WRITE_KNOWN_TYPE(&x, 1);
494 }
495
496 void AbstractDumpWriter::write_u2(u2 x) {
497 u2 v;
498 Bytes::put_Java_u2((address)&v, x);
499 WRITE_KNOWN_TYPE(&v, 2);
500 }
501
502 void AbstractDumpWriter::write_u4(u4 x) {
503 u4 v;
504 Bytes::put_Java_u4((address)&v, x);
505 WRITE_KNOWN_TYPE(&v, 4);
506 }
507
508 void AbstractDumpWriter::write_u8(u8 x) {
509 u8 v;
510 Bytes::put_Java_u8((address)&v, x);
511 WRITE_KNOWN_TYPE(&v, 8);
512 }
513
514 void AbstractDumpWriter::write_address(address a) {
515 #ifdef _LP64
516 write_u8((u8)a);
517 #else
518 write_u4((u4)a);
519 #endif
520 }
521
522 void AbstractDumpWriter::write_objectID(oop o) {
523 write_address(cast_from_oop<address>(o));
524 }
525
526 void AbstractDumpWriter::write_rootID(oop* p) {
527 write_address((address)p);
528 }
529
530 void AbstractDumpWriter::write_symbolID(Symbol* s) {
531 write_address((address)((uintptr_t)s));
532 }
533
534 void AbstractDumpWriter::write_id(u4 x) {
535 #ifdef _LP64
536 write_u8((u8) x);
537 #else
538 write_u4(x);
539 #endif
540 }
541
542 // We use java mirror as the class ID
543 void AbstractDumpWriter::write_classID(Klass* k) {
544 write_objectID(k->java_mirror());
545 }
546
547 void AbstractDumpWriter::finish_dump_segment() {
548 if (_in_dump_segment) {
549 assert(_sub_record_left == 0, "Last sub-record not written completely");
550 assert(_sub_record_ended, "sub-record must have ended");
551
552 // Fix up the dump segment length if we haven't written a huge sub-record last
553 // (in which case the segment length was already set to the correct value initially).
554 if (!_is_huge_sub_record) {
555 assert(position() > dump_segment_header_size, "Dump segment should have some content");
556 Bytes::put_Java_u4((address) (buffer() + 5),
557 (u4) (position() - dump_segment_header_size));
558 } else {
559 // Finish process huge sub record
560 // Set _is_huge_sub_record to false so the parallel dump writer can flush data to file.
561 _is_huge_sub_record = false;
562 }
563
564 _in_dump_segment = false;
565 flush();
566 }
567 }
568
569 void AbstractDumpWriter::start_sub_record(u1 tag, u4 len) {
570 if (!_in_dump_segment) {
571 if (position() > 0) {
572 flush();
573 }
574
575 assert(position() == 0 && buffer_size() > dump_segment_header_size, "Must be at the start");
576
577 write_u1(HPROF_HEAP_DUMP_SEGMENT);
578 write_u4(0); // timestamp
579 // Will be fixed up later if we add more sub-records. If this is a huge sub-record,
580 // this is already the correct length, since we don't add more sub-records.
581 write_u4(len);
582 assert(Bytes::get_Java_u4((address)(buffer() + 5)) == len, "Inconsistent size!");
583 _in_dump_segment = true;
584 _is_huge_sub_record = len > buffer_size() - dump_segment_header_size;
585 } else if (_is_huge_sub_record || (len > buffer_size() - position())) {
586 // This object will not fit in completely or the last sub-record was huge.
587 // Finish the current segment and try again.
588 finish_dump_segment();
589 start_sub_record(tag, len);
590
591 return;
592 }
593
594 debug_only(_sub_record_left = len);
595 debug_only(_sub_record_ended = false);
596
597 write_u1(tag);
598 }
599
600 void AbstractDumpWriter::end_sub_record() {
601 assert(_in_dump_segment, "must be in dump segment");
602 assert(_sub_record_left == 0, "sub-record not written completely");
603 assert(!_sub_record_ended, "Must not have ended yet");
604 debug_only(_sub_record_ended = true);
605 }
606
607 // Supports I/O operations for a dump
608
609 class DumpWriter : public AbstractDumpWriter {
610 private:
611 FileWriter* _writer;
612 AbstractCompressor* _compressor;
613 size_t _bytes_written;
614 char* _error;
615 // Compression support
616 char* _out_buffer;
617 size_t _out_size;
618 size_t _out_pos;
619 char* _tmp_buffer;
620 size_t _tmp_size;
621
622 private:
623 void do_compress();
624
625 public:
626 DumpWriter(const char* path, bool overwrite, AbstractCompressor* compressor);
627 ~DumpWriter();
628 julong bytes_written() const override { return (julong) _bytes_written; }
629 void set_bytes_written(julong bytes_written) { _bytes_written = bytes_written; }
630 char const* error() const override { return _error; }
631 void set_error(const char* error) { _error = (char*)error; }
632 bool has_error() const { return _error != nullptr; }
633 const char* get_file_path() const { return _writer->get_file_path(); }
634 AbstractCompressor* compressor() { return _compressor; }
635 void set_compressor(AbstractCompressor* p) { _compressor = p; }
636 bool is_overwrite() const { return _writer->is_overwrite(); }
637 int get_fd() const { return _writer->get_fd(); }
638
639 void flush() override;
640 };
641
642 DumpWriter::DumpWriter(const char* path, bool overwrite, AbstractCompressor* compressor) :
643 AbstractDumpWriter(),
644 _writer(new (std::nothrow) FileWriter(path, overwrite)),
645 _compressor(compressor),
646 _bytes_written(0),
647 _error(nullptr),
648 _out_buffer(nullptr),
649 _out_size(0),
650 _out_pos(0),
651 _tmp_buffer(nullptr),
652 _tmp_size(0) {
653 _error = (char*)_writer->open_writer();
654 if (_error == nullptr) {
655 _buffer = (char*)os::malloc(io_buffer_max_size, mtInternal);
656 if (compressor != nullptr) {
657 _error = (char*)_compressor->init(io_buffer_max_size, &_out_size, &_tmp_size);
658 if (_error == nullptr) {
659 if (_out_size > 0) {
660 _out_buffer = (char*)os::malloc(_out_size, mtInternal);
661 }
662 if (_tmp_size > 0) {
663 _tmp_buffer = (char*)os::malloc(_tmp_size, mtInternal);
664 }
665 }
666 }
667 }
668 // initialize internal buffer
669 _pos = 0;
670 _size = io_buffer_max_size;
671 }
672
673 DumpWriter::~DumpWriter(){
674 if (_buffer != nullptr) {
675 os::free(_buffer);
676 }
677 if (_out_buffer != nullptr) {
678 os::free(_out_buffer);
679 }
680 if (_tmp_buffer != nullptr) {
681 os::free(_tmp_buffer);
682 }
683 if (_writer != NULL) {
684 delete _writer;
685 }
686 _bytes_written = -1;
687 }
688
689 // flush any buffered bytes to the file
690 void DumpWriter::flush() {
691 if (_pos <= 0) {
692 return;
693 }
694 if (has_error()) {
695 _pos = 0;
696 return;
697 }
698 char* result = nullptr;
699 if (_compressor == nullptr) {
700 result = (char*)_writer->write_buf(_buffer, _pos);
701 _bytes_written += _pos;
702 } else {
703 do_compress();
704 if (!has_error()) {
705 result = (char*)_writer->write_buf(_out_buffer, _out_pos);
706 _bytes_written += _out_pos;
707 }
708 }
709 _pos = 0; // reset pos to make internal buffer available
710
711 if (result != nullptr) {
712 set_error(result);
713 }
714 }
715
716 void DumpWriter::do_compress() {
717 const char* msg = _compressor->compress(_buffer, _pos, _out_buffer, _out_size,
718 _tmp_buffer, _tmp_size, &_out_pos);
719
720 if (msg != nullptr) {
721 set_error(msg);
722 }
723 }
724
725 class DumperClassCacheTable;
726 class DumperClassCacheTableEntry;
727
728 // Support class with a collection of functions used when dumping the heap
729 class DumperSupport : AllStatic {
730 public:
731
732 // write a header of the given type
733 static void write_header(AbstractDumpWriter* writer, hprofTag tag, u4 len);
734
735 // returns hprof tag for the given type signature
736 static hprofTag sig2tag(Symbol* sig);
737 // returns hprof tag for the given basic type
738 static hprofTag type2tag(BasicType type);
739 // Returns the size of the data to write.
740 static u4 sig2size(Symbol* sig);
741
742 // returns the size of the instance of the given class
743 static u4 instance_size(InstanceKlass* ik, DumperClassCacheTableEntry* class_cache_entry = nullptr);
744
745 // dump a jfloat
746 static void dump_float(AbstractDumpWriter* writer, jfloat f);
747 // dump a jdouble
748 static void dump_double(AbstractDumpWriter* writer, jdouble d);
749 // dumps the raw value of the given field
750 static void dump_field_value(AbstractDumpWriter* writer, char type, oop obj, int offset);
751 // returns the size of the static fields; also counts the static fields
752 static u4 get_static_fields_size(InstanceKlass* ik, u2& field_count);
753 // dumps static fields of the given class
754 static void dump_static_fields(AbstractDumpWriter* writer, Klass* k);
755 // dump the raw values of the instance fields of the given object
756 static void dump_instance_fields(AbstractDumpWriter* writer, oop o, DumperClassCacheTableEntry* class_cache_entry);
757 // get the count of the instance fields for a given class
758 static u2 get_instance_fields_count(InstanceKlass* ik);
759 // dumps the definition of the instance fields for a given class
760 static void dump_instance_field_descriptors(AbstractDumpWriter* writer, Klass* k);
761 // creates HPROF_GC_INSTANCE_DUMP record for the given object
762 static void dump_instance(AbstractDumpWriter* writer, oop o, DumperClassCacheTable* class_cache);
763 // creates HPROF_GC_CLASS_DUMP record for the given instance class
764 static void dump_instance_class(AbstractDumpWriter* writer, Klass* k);
765 // creates HPROF_GC_CLASS_DUMP record for a given array class
766 static void dump_array_class(AbstractDumpWriter* writer, Klass* k);
767
768 // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
769 static void dump_object_array(AbstractDumpWriter* writer, objArrayOop array);
770 // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
771 static void dump_prim_array(AbstractDumpWriter* writer, typeArrayOop array);
772 // create HPROF_FRAME record for the given method and bci
773 static void dump_stack_frame(AbstractDumpWriter* writer, int frame_serial_num, int class_serial_num, Method* m, int bci);
774
775 // check if we need to truncate an array
776 static int calculate_array_max_length(AbstractDumpWriter* writer, arrayOop array, short header_size);
777
778 // fixes up the current dump record and writes HPROF_HEAP_DUMP_END record
779 static void end_of_dump(AbstractDumpWriter* writer);
780
781 static oop mask_dormant_archived_object(oop o, oop ref_obj) {
782 if (o != nullptr && o->klass()->java_mirror_no_keepalive() == nullptr) {
783 // Ignore this object since the corresponding java mirror is not loaded.
784 // Might be a dormant archive object.
785 report_dormant_archived_object(o, ref_obj);
786 return nullptr;
787 } else {
788 return o;
789 }
790 }
791
792 static void report_dormant_archived_object(oop o, oop ref_obj) {
793 if (log_is_enabled(Trace, cds, heap)) {
794 ResourceMark rm;
795 if (ref_obj != nullptr) {
796 log_trace(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s) referenced by " INTPTR_FORMAT " (%s)",
797 p2i(o), o->klass()->external_name(),
798 p2i(ref_obj), ref_obj->klass()->external_name());
799 } else {
800 log_trace(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s)",
801 p2i(o), o->klass()->external_name());
802 }
803 }
804 }
805 };
806
807 // Hash table of klasses to the klass metadata. This should greatly improve the
808 // hash dumping performance. This hash table is supposed to be used by a single
809 // thread only.
810 //
811 class DumperClassCacheTableEntry : public CHeapObj<mtServiceability> {
812 friend class DumperClassCacheTable;
813 private:
814 GrowableArray<char> _sigs_start;
815 GrowableArray<int> _offsets;
816 u4 _instance_size;
817 int _entries;
818
819 public:
820 DumperClassCacheTableEntry() : _instance_size(0), _entries(0) {};
821
822 int field_count() { return _entries; }
823 char sig_start(int field_idx) { return _sigs_start.at(field_idx); }
824 int offset(int field_idx) { return _offsets.at(field_idx); }
825 u4 instance_size() { return _instance_size; }
826 };
827
828 class DumperClassCacheTable {
829 private:
830 // ResourceHashtable SIZE is specified at compile time so we
831 // use 1031 which is the first prime after 1024.
832 static constexpr size_t TABLE_SIZE = 1031;
833
834 // Maintain the cache for N classes. This limits memory footprint
835 // impact, regardless of how many classes we have in the dump.
836 // This also improves look up performance by keeping the statically
837 // sized table from overloading.
838 static constexpr int CACHE_TOP = 256;
839
840 typedef ResourceHashtable<InstanceKlass*, DumperClassCacheTableEntry*,
841 TABLE_SIZE, AnyObj::C_HEAP, mtServiceability> PtrTable;
842 PtrTable* _ptrs;
843
844 // Single-slot cache to handle the major case of objects of the same
845 // class back-to-back, e.g. from T[].
846 InstanceKlass* _last_ik;
847 DumperClassCacheTableEntry* _last_entry;
848
849 void unlink_all(PtrTable* table) {
850 class CleanupEntry: StackObj {
851 public:
852 bool do_entry(InstanceKlass*& key, DumperClassCacheTableEntry*& entry) {
853 delete entry;
854 return true;
855 }
856 } cleanup;
857 table->unlink(&cleanup);
858 }
859
860 public:
861 DumperClassCacheTableEntry* lookup_or_create(InstanceKlass* ik) {
862 if (_last_ik == ik) {
863 return _last_entry;
864 }
865
866 DumperClassCacheTableEntry* entry;
867 DumperClassCacheTableEntry** from_cache = _ptrs->get(ik);
868 if (from_cache == nullptr) {
869 entry = new DumperClassCacheTableEntry();
870 for (HierarchicalFieldStream<JavaFieldStream> fld(ik); !fld.done(); fld.next()) {
871 if (!fld.access_flags().is_static()) {
872 Symbol* sig = fld.signature();
873 entry->_sigs_start.push(sig->char_at(0));
874 entry->_offsets.push(fld.offset());
875 entry->_entries++;
876 entry->_instance_size += DumperSupport::sig2size(sig);
877 }
878 }
879
880 if (_ptrs->number_of_entries() >= CACHE_TOP) {
881 // We do not track the individual hit rates for table entries.
882 // Purge the entire table, and let the cache catch up with new
883 // distribution.
884 unlink_all(_ptrs);
885 }
886
887 _ptrs->put(ik, entry);
888 } else {
889 entry = *from_cache;
890 }
891
892 // Remember for single-slot cache.
893 _last_ik = ik;
894 _last_entry = entry;
895
896 return entry;
897 }
898
899 DumperClassCacheTable() : _ptrs(new (mtServiceability) PtrTable), _last_ik(nullptr), _last_entry(nullptr) {}
900
901 ~DumperClassCacheTable() {
902 unlink_all(_ptrs);
903 delete _ptrs;
904 }
905 };
906
907 // write a header of the given type
908 void DumperSupport:: write_header(AbstractDumpWriter* writer, hprofTag tag, u4 len) {
909 writer->write_u1(tag);
910 writer->write_u4(0); // current ticks
911 writer->write_u4(len);
912 }
913
914 // returns hprof tag for the given type signature
915 hprofTag DumperSupport::sig2tag(Symbol* sig) {
916 switch (sig->char_at(0)) {
917 case JVM_SIGNATURE_CLASS : return HPROF_NORMAL_OBJECT;
918 case JVM_SIGNATURE_ARRAY : return HPROF_NORMAL_OBJECT;
919 case JVM_SIGNATURE_BYTE : return HPROF_BYTE;
920 case JVM_SIGNATURE_CHAR : return HPROF_CHAR;
921 case JVM_SIGNATURE_FLOAT : return HPROF_FLOAT;
922 case JVM_SIGNATURE_DOUBLE : return HPROF_DOUBLE;
923 case JVM_SIGNATURE_INT : return HPROF_INT;
924 case JVM_SIGNATURE_LONG : return HPROF_LONG;
925 case JVM_SIGNATURE_SHORT : return HPROF_SHORT;
926 case JVM_SIGNATURE_BOOLEAN : return HPROF_BOOLEAN;
927 default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
928 }
929 }
930
931 hprofTag DumperSupport::type2tag(BasicType type) {
932 switch (type) {
933 case T_BYTE : return HPROF_BYTE;
934 case T_CHAR : return HPROF_CHAR;
935 case T_FLOAT : return HPROF_FLOAT;
936 case T_DOUBLE : return HPROF_DOUBLE;
937 case T_INT : return HPROF_INT;
938 case T_LONG : return HPROF_LONG;
939 case T_SHORT : return HPROF_SHORT;
940 case T_BOOLEAN : return HPROF_BOOLEAN;
941 default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
942 }
943 }
944
945 u4 DumperSupport::sig2size(Symbol* sig) {
946 switch (sig->char_at(0)) {
947 case JVM_SIGNATURE_CLASS:
948 case JVM_SIGNATURE_ARRAY: return sizeof(address);
949 case JVM_SIGNATURE_BOOLEAN:
950 case JVM_SIGNATURE_BYTE: return 1;
951 case JVM_SIGNATURE_SHORT:
952 case JVM_SIGNATURE_CHAR: return 2;
953 case JVM_SIGNATURE_INT:
954 case JVM_SIGNATURE_FLOAT: return 4;
955 case JVM_SIGNATURE_LONG:
956 case JVM_SIGNATURE_DOUBLE: return 8;
957 default: ShouldNotReachHere(); /* to shut up compiler */ return 0;
958 }
959 }
960
961 template<typename T, typename F> T bit_cast(F from) { // replace with the real thing when we can use c++20
962 T to;
963 static_assert(sizeof(to) == sizeof(from), "must be of the same size");
964 memcpy(&to, &from, sizeof(to));
965 return to;
966 }
967
968 // dump a jfloat
969 void DumperSupport::dump_float(AbstractDumpWriter* writer, jfloat f) {
970 if (g_isnan(f)) {
971 writer->write_u4(0x7fc00000); // collapsing NaNs
972 } else {
973 writer->write_u4(bit_cast<u4>(f));
974 }
975 }
976
977 // dump a jdouble
978 void DumperSupport::dump_double(AbstractDumpWriter* writer, jdouble d) {
979 if (g_isnan(d)) {
980 writer->write_u8(0x7ff80000ull << 32); // collapsing NaNs
981 } else {
982 writer->write_u8(bit_cast<u8>(d));
983 }
984 }
985
986 // dumps the raw value of the given field
987 void DumperSupport::dump_field_value(AbstractDumpWriter* writer, char type, oop obj, int offset) {
988 switch (type) {
989 case JVM_SIGNATURE_CLASS :
990 case JVM_SIGNATURE_ARRAY : {
991 oop o = obj->obj_field_access<ON_UNKNOWN_OOP_REF | AS_NO_KEEPALIVE>(offset);
992 o = mask_dormant_archived_object(o, obj);
993 assert(oopDesc::is_oop_or_null(o), "Expected an oop or nullptr at " PTR_FORMAT, p2i(o));
994 writer->write_objectID(o);
995 break;
996 }
997 case JVM_SIGNATURE_BYTE : {
998 jbyte b = obj->byte_field(offset);
999 writer->write_u1(b);
1000 break;
1001 }
1002 case JVM_SIGNATURE_CHAR : {
1003 jchar c = obj->char_field(offset);
1004 writer->write_u2(c);
1005 break;
1006 }
1007 case JVM_SIGNATURE_SHORT : {
1008 jshort s = obj->short_field(offset);
1009 writer->write_u2(s);
1010 break;
1011 }
1012 case JVM_SIGNATURE_FLOAT : {
1013 jfloat f = obj->float_field(offset);
1014 dump_float(writer, f);
1015 break;
1016 }
1017 case JVM_SIGNATURE_DOUBLE : {
1018 jdouble d = obj->double_field(offset);
1019 dump_double(writer, d);
1020 break;
1021 }
1022 case JVM_SIGNATURE_INT : {
1023 jint i = obj->int_field(offset);
1024 writer->write_u4(i);
1025 break;
1026 }
1027 case JVM_SIGNATURE_LONG : {
1028 jlong l = obj->long_field(offset);
1029 writer->write_u8(l);
1030 break;
1031 }
1032 case JVM_SIGNATURE_BOOLEAN : {
1033 jboolean b = obj->bool_field(offset);
1034 writer->write_u1(b);
1035 break;
1036 }
1037 default : {
1038 ShouldNotReachHere();
1039 break;
1040 }
1041 }
1042 }
1043
1044 // returns the size of the instance of the given class
1045 u4 DumperSupport::instance_size(InstanceKlass* ik, DumperClassCacheTableEntry* class_cache_entry) {
1046 if (class_cache_entry != nullptr) {
1047 return class_cache_entry->instance_size();
1048 } else {
1049 u4 size = 0;
1050 for (HierarchicalFieldStream<JavaFieldStream> fld(ik); !fld.done(); fld.next()) {
1051 if (!fld.access_flags().is_static()) {
1052 size += sig2size(fld.signature());
1053 }
1054 }
1055 return size;
1056 }
1057 }
1058
1059 u4 DumperSupport::get_static_fields_size(InstanceKlass* ik, u2& field_count) {
1060 field_count = 0;
1061 u4 size = 0;
1062
1063 for (JavaFieldStream fldc(ik); !fldc.done(); fldc.next()) {
1064 if (fldc.access_flags().is_static()) {
1065 field_count++;
1066 size += sig2size(fldc.signature());
1067 }
1068 }
1069
1070 // Add in resolved_references which is referenced by the cpCache
1071 // The resolved_references is an array per InstanceKlass holding the
1072 // strings and other oops resolved from the constant pool.
1073 oop resolved_references = ik->constants()->resolved_references_or_null();
1074 if (resolved_references != nullptr) {
1075 field_count++;
1076 size += sizeof(address);
1077
1078 // Add in the resolved_references of the used previous versions of the class
1079 // in the case of RedefineClasses
1080 InstanceKlass* prev = ik->previous_versions();
1081 while (prev != nullptr && prev->constants()->resolved_references_or_null() != nullptr) {
1082 field_count++;
1083 size += sizeof(address);
1084 prev = prev->previous_versions();
1085 }
1086 }
1087
1088 // We write the value itself plus a name and a one byte type tag per field.
1089 return checked_cast<u4>(size + field_count * (sizeof(address) + 1));
1090 }
1091
1092 // dumps static fields of the given class
1093 void DumperSupport::dump_static_fields(AbstractDumpWriter* writer, Klass* k) {
1094 InstanceKlass* ik = InstanceKlass::cast(k);
1095
1096 // dump the field descriptors and raw values
1097 for (JavaFieldStream fld(ik); !fld.done(); fld.next()) {
1098 if (fld.access_flags().is_static()) {
1099 Symbol* sig = fld.signature();
1100
1101 writer->write_symbolID(fld.name()); // name
1102 writer->write_u1(sig2tag(sig)); // type
1103
1104 // value
1105 dump_field_value(writer, sig->char_at(0), ik->java_mirror(), fld.offset());
1106 }
1107 }
1108
1109 // Add resolved_references for each class that has them
1110 oop resolved_references = ik->constants()->resolved_references_or_null();
1111 if (resolved_references != nullptr) {
1112 writer->write_symbolID(vmSymbols::resolved_references_name()); // name
1113 writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
1114 writer->write_objectID(resolved_references);
1115
1116 // Also write any previous versions
1117 InstanceKlass* prev = ik->previous_versions();
1118 while (prev != nullptr && prev->constants()->resolved_references_or_null() != nullptr) {
1119 writer->write_symbolID(vmSymbols::resolved_references_name()); // name
1120 writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
1121 writer->write_objectID(prev->constants()->resolved_references());
1122 prev = prev->previous_versions();
1123 }
1124 }
1125 }
1126
1127 // dump the raw values of the instance fields of the given object
1128 void DumperSupport::dump_instance_fields(AbstractDumpWriter* writer, oop o, DumperClassCacheTableEntry* class_cache_entry) {
1129 assert(class_cache_entry != nullptr, "Pre-condition: must be provided");
1130 for (int idx = 0; idx < class_cache_entry->field_count(); idx++) {
1131 dump_field_value(writer, class_cache_entry->sig_start(idx), o, class_cache_entry->offset(idx));
1132 }
1133 }
1134
1135 // dumps the definition of the instance fields for a given class
1136 u2 DumperSupport::get_instance_fields_count(InstanceKlass* ik) {
1137 u2 field_count = 0;
1138
1139 for (JavaFieldStream fldc(ik); !fldc.done(); fldc.next()) {
1140 if (!fldc.access_flags().is_static()) field_count++;
1141 }
1142
1143 return field_count;
1144 }
1145
1146 // dumps the definition of the instance fields for a given class
1147 void DumperSupport::dump_instance_field_descriptors(AbstractDumpWriter* writer, Klass* k) {
1148 InstanceKlass* ik = InstanceKlass::cast(k);
1149
1150 // dump the field descriptors
1151 for (JavaFieldStream fld(ik); !fld.done(); fld.next()) {
1152 if (!fld.access_flags().is_static()) {
1153 Symbol* sig = fld.signature();
1154
1155 writer->write_symbolID(fld.name()); // name
1156 writer->write_u1(sig2tag(sig)); // type
1157 }
1158 }
1159 }
1160
1161 // creates HPROF_GC_INSTANCE_DUMP record for the given object
1162 void DumperSupport::dump_instance(AbstractDumpWriter* writer, oop o, DumperClassCacheTable* class_cache) {
1163 InstanceKlass* ik = InstanceKlass::cast(o->klass());
1164
1165 DumperClassCacheTableEntry* cache_entry = class_cache->lookup_or_create(ik);
1166
1167 u4 is = instance_size(ik, cache_entry);
1168 u4 size = 1 + sizeof(address) + 4 + sizeof(address) + 4 + is;
1169
1170 writer->start_sub_record(HPROF_GC_INSTANCE_DUMP, size);
1171 writer->write_objectID(o);
1172 writer->write_u4(STACK_TRACE_ID);
1173
1174 // class ID
1175 writer->write_classID(ik);
1176
1177 // number of bytes that follow
1178 writer->write_u4(is);
1179
1180 // field values
1181 dump_instance_fields(writer, o, cache_entry);
1182
1183 writer->end_sub_record();
1184 }
1185
1186 // creates HPROF_GC_CLASS_DUMP record for the given instance class
1187 void DumperSupport::dump_instance_class(AbstractDumpWriter* writer, Klass* k) {
1188 InstanceKlass* ik = InstanceKlass::cast(k);
1189
1190 // We can safepoint and do a heap dump at a point where we have a Klass,
1191 // but no java mirror class has been setup for it. So we need to check
1192 // that the class is at least loaded, to avoid crash from a null mirror.
1193 if (!ik->is_loaded()) {
1194 return;
1195 }
1196
1197 u2 static_fields_count = 0;
1198 u4 static_size = get_static_fields_size(ik, static_fields_count);
1199 u2 instance_fields_count = get_instance_fields_count(ik);
1200 u4 instance_fields_size = instance_fields_count * (sizeof(address) + 1);
1201 u4 size = checked_cast<u4>(1 + sizeof(address) + 4 + 6 * sizeof(address) + 4 + 2 + 2 + static_size + 2 + instance_fields_size);
1202
1203 writer->start_sub_record(HPROF_GC_CLASS_DUMP, size);
1204
1205 // class ID
1206 writer->write_classID(ik);
1207 writer->write_u4(STACK_TRACE_ID);
1208
1209 // super class ID
1210 InstanceKlass* java_super = ik->java_super();
1211 if (java_super == nullptr) {
1212 writer->write_objectID(oop(nullptr));
1213 } else {
1214 writer->write_classID(java_super);
1215 }
1216
1217 writer->write_objectID(ik->class_loader());
1218 writer->write_objectID(ik->signers());
1219 writer->write_objectID(ik->protection_domain());
1220
1221 // reserved
1222 writer->write_objectID(oop(nullptr));
1223 writer->write_objectID(oop(nullptr));
1224
1225 // instance size
1226 writer->write_u4(DumperSupport::instance_size(ik));
1227
1228 // size of constant pool - ignored by HAT 1.1
1229 writer->write_u2(0);
1230
1231 // static fields
1232 writer->write_u2(static_fields_count);
1233 dump_static_fields(writer, ik);
1234
1235 // description of instance fields
1236 writer->write_u2(instance_fields_count);
1237 dump_instance_field_descriptors(writer, ik);
1238
1239 writer->end_sub_record();
1240 }
1241
1242 // creates HPROF_GC_CLASS_DUMP record for the given array class
1243 void DumperSupport::dump_array_class(AbstractDumpWriter* writer, Klass* k) {
1244 InstanceKlass* ik = nullptr; // bottom class for object arrays, null for primitive type arrays
1245 if (k->is_objArray_klass()) {
1246 Klass *bk = ObjArrayKlass::cast(k)->bottom_klass();
1247 assert(bk != nullptr, "checking");
1248 if (bk->is_instance_klass()) {
1249 ik = InstanceKlass::cast(bk);
1250 }
1251 }
1252
1253 u4 size = 1 + sizeof(address) + 4 + 6 * sizeof(address) + 4 + 2 + 2 + 2;
1254 writer->start_sub_record(HPROF_GC_CLASS_DUMP, size);
1255 writer->write_classID(k);
1256 writer->write_u4(STACK_TRACE_ID);
1257
1258 // super class of array classes is java.lang.Object
1259 InstanceKlass* java_super = k->java_super();
1260 assert(java_super != nullptr, "checking");
1261 writer->write_classID(java_super);
1262
1263 writer->write_objectID(ik == nullptr ? oop(nullptr) : ik->class_loader());
1264 writer->write_objectID(ik == nullptr ? oop(nullptr) : ik->signers());
1265 writer->write_objectID(ik == nullptr ? oop(nullptr) : ik->protection_domain());
1266
1267 writer->write_objectID(oop(nullptr)); // reserved
1268 writer->write_objectID(oop(nullptr));
1269 writer->write_u4(0); // instance size
1270 writer->write_u2(0); // constant pool
1271 writer->write_u2(0); // static fields
1272 writer->write_u2(0); // instance fields
1273
1274 writer->end_sub_record();
1275
1276 }
1277
1278 // Hprof uses an u4 as record length field,
1279 // which means we need to truncate arrays that are too long.
1280 int DumperSupport::calculate_array_max_length(AbstractDumpWriter* writer, arrayOop array, short header_size) {
1281 BasicType type = ArrayKlass::cast(array->klass())->element_type();
1282 assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type");
1283
1284 int length = array->length();
1285
1286 int type_size;
1287 if (type == T_OBJECT) {
1288 type_size = sizeof(address);
1289 } else {
1290 type_size = type2aelembytes(type);
1291 }
1292
1293 size_t length_in_bytes = (size_t)length * type_size;
1294 uint max_bytes = max_juint - header_size;
1295
1296 if (length_in_bytes > max_bytes) {
1297 length = max_bytes / type_size;
1298 length_in_bytes = (size_t)length * type_size;
1299
1300 warning("cannot dump array of type %s[] with length %d; truncating to length %d",
1301 type2name_tab[type], array->length(), length);
1302 }
1303 return length;
1304 }
1305
1306 // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
1307 void DumperSupport::dump_object_array(AbstractDumpWriter* writer, objArrayOop array) {
1308 // sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID) + sizeof(classID)
1309 short header_size = 1 + 2 * 4 + 2 * sizeof(address);
1310 int length = calculate_array_max_length(writer, array, header_size);
1311 u4 size = checked_cast<u4>(header_size + length * sizeof(address));
1312
1313 writer->start_sub_record(HPROF_GC_OBJ_ARRAY_DUMP, size);
1314 writer->write_objectID(array);
1315 writer->write_u4(STACK_TRACE_ID);
1316 writer->write_u4(length);
1317
1318 // array class ID
1319 writer->write_classID(array->klass());
1320
1321 // [id]* elements
1322 for (int index = 0; index < length; index++) {
1323 oop o = array->obj_at(index);
1324 o = mask_dormant_archived_object(o, array);
1325 writer->write_objectID(o);
1326 }
1327
1328 writer->end_sub_record();
1329 }
1330
1331 #define WRITE_ARRAY(Array, Type, Size, Length) \
1332 for (int i = 0; i < Length; i++) { writer->write_##Size((Size)Array->Type##_at(i)); }
1333
1334 // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
1335 void DumperSupport::dump_prim_array(AbstractDumpWriter* writer, typeArrayOop array) {
1336 BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
1337 // 2 * sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID)
1338 short header_size = 2 * 1 + 2 * 4 + sizeof(address);
1339
1340 int length = calculate_array_max_length(writer, array, header_size);
1341 int type_size = type2aelembytes(type);
1342 u4 length_in_bytes = (u4)length * type_size;
1343 u4 size = header_size + length_in_bytes;
1344
1345 writer->start_sub_record(HPROF_GC_PRIM_ARRAY_DUMP, size);
1346 writer->write_objectID(array);
1347 writer->write_u4(STACK_TRACE_ID);
1348 writer->write_u4(length);
1349 writer->write_u1(type2tag(type));
1350
1351 // nothing to copy
1352 if (length == 0) {
1353 writer->end_sub_record();
1354 return;
1355 }
1356
1357 // If the byte ordering is big endian then we can copy most types directly
1358
1359 switch (type) {
1360 case T_INT : {
1361 if (Endian::is_Java_byte_ordering_different()) {
1362 WRITE_ARRAY(array, int, u4, length);
1363 } else {
1364 writer->write_raw(array->int_at_addr(0), length_in_bytes);
1365 }
1366 break;
1367 }
1368 case T_BYTE : {
1369 writer->write_raw(array->byte_at_addr(0), length_in_bytes);
1370 break;
1371 }
1372 case T_CHAR : {
1373 if (Endian::is_Java_byte_ordering_different()) {
1374 WRITE_ARRAY(array, char, u2, length);
1375 } else {
1376 writer->write_raw(array->char_at_addr(0), length_in_bytes);
1377 }
1378 break;
1379 }
1380 case T_SHORT : {
1381 if (Endian::is_Java_byte_ordering_different()) {
1382 WRITE_ARRAY(array, short, u2, length);
1383 } else {
1384 writer->write_raw(array->short_at_addr(0), length_in_bytes);
1385 }
1386 break;
1387 }
1388 case T_BOOLEAN : {
1389 if (Endian::is_Java_byte_ordering_different()) {
1390 WRITE_ARRAY(array, bool, u1, length);
1391 } else {
1392 writer->write_raw(array->bool_at_addr(0), length_in_bytes);
1393 }
1394 break;
1395 }
1396 case T_LONG : {
1397 if (Endian::is_Java_byte_ordering_different()) {
1398 WRITE_ARRAY(array, long, u8, length);
1399 } else {
1400 writer->write_raw(array->long_at_addr(0), length_in_bytes);
1401 }
1402 break;
1403 }
1404
1405 // handle float/doubles in a special value to ensure than NaNs are
1406 // written correctly. TO DO: Check if we can avoid this on processors that
1407 // use IEEE 754.
1408
1409 case T_FLOAT : {
1410 for (int i = 0; i < length; i++) {
1411 dump_float(writer, array->float_at(i));
1412 }
1413 break;
1414 }
1415 case T_DOUBLE : {
1416 for (int i = 0; i < length; i++) {
1417 dump_double(writer, array->double_at(i));
1418 }
1419 break;
1420 }
1421 default : ShouldNotReachHere();
1422 }
1423
1424 writer->end_sub_record();
1425 }
1426
1427 // create a HPROF_FRAME record of the given Method* and bci
1428 void DumperSupport::dump_stack_frame(AbstractDumpWriter* writer,
1429 int frame_serial_num,
1430 int class_serial_num,
1431 Method* m,
1432 int bci) {
1433 int line_number;
1434 if (m->is_native()) {
1435 line_number = -3; // native frame
1436 } else {
1437 line_number = m->line_number_from_bci(bci);
1438 }
1439
1440 write_header(writer, HPROF_FRAME, 4*oopSize + 2*sizeof(u4));
1441 writer->write_id(frame_serial_num); // frame serial number
1442 writer->write_symbolID(m->name()); // method's name
1443 writer->write_symbolID(m->signature()); // method's signature
1444
1445 assert(m->method_holder()->is_instance_klass(), "not InstanceKlass");
1446 writer->write_symbolID(m->method_holder()->source_file_name()); // source file name
1447 writer->write_u4(class_serial_num); // class serial number
1448 writer->write_u4((u4) line_number); // line number
1449 }
1450
1451
1452 // Support class used to generate HPROF_UTF8 records from the entries in the
1453 // SymbolTable.
1454
1455 class SymbolTableDumper : public SymbolClosure {
1456 private:
1457 AbstractDumpWriter* _writer;
1458 AbstractDumpWriter* writer() const { return _writer; }
1459 public:
1460 SymbolTableDumper(AbstractDumpWriter* writer) { _writer = writer; }
1461 void do_symbol(Symbol** p);
1462 };
1463
1464 void SymbolTableDumper::do_symbol(Symbol** p) {
1465 ResourceMark rm;
1466 Symbol* sym = *p;
1467 int len = sym->utf8_length();
1468 if (len > 0) {
1469 char* s = sym->as_utf8();
1470 DumperSupport::write_header(writer(), HPROF_UTF8, oopSize + len);
1471 writer()->write_symbolID(sym);
1472 writer()->write_raw(s, len);
1473 }
1474 }
1475
1476 // Support class used to generate HPROF_GC_ROOT_JNI_LOCAL records
1477
1478 class JNILocalsDumper : public OopClosure {
1479 private:
1480 AbstractDumpWriter* _writer;
1481 u4 _thread_serial_num;
1482 int _frame_num;
1483 AbstractDumpWriter* writer() const { return _writer; }
1484 public:
1485 JNILocalsDumper(AbstractDumpWriter* writer, u4 thread_serial_num) {
1486 _writer = writer;
1487 _thread_serial_num = thread_serial_num;
1488 _frame_num = -1; // default - empty stack
1489 }
1490 void set_frame_number(int n) { _frame_num = n; }
1491 void do_oop(oop* obj_p);
1492 void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1493 };
1494
1495 void JNILocalsDumper::do_oop(oop* obj_p) {
1496 // ignore null handles
1497 oop o = *obj_p;
1498 if (o != nullptr) {
1499 u4 size = 1 + sizeof(address) + 4 + 4;
1500 writer()->start_sub_record(HPROF_GC_ROOT_JNI_LOCAL, size);
1501 writer()->write_objectID(o);
1502 writer()->write_u4(_thread_serial_num);
1503 writer()->write_u4((u4)_frame_num);
1504 writer()->end_sub_record();
1505 }
1506 }
1507
1508
1509 // Support class used to generate HPROF_GC_ROOT_JNI_GLOBAL records
1510
1511 class JNIGlobalsDumper : public OopClosure {
1512 private:
1513 AbstractDumpWriter* _writer;
1514 AbstractDumpWriter* writer() const { return _writer; }
1515
1516 public:
1517 JNIGlobalsDumper(AbstractDumpWriter* writer) {
1518 _writer = writer;
1519 }
1520 void do_oop(oop* obj_p);
1521 void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1522 };
1523
1524 void JNIGlobalsDumper::do_oop(oop* obj_p) {
1525 oop o = NativeAccess<AS_NO_KEEPALIVE>::oop_load(obj_p);
1526
1527 // ignore these
1528 if (o == nullptr) return;
1529 // we ignore global ref to symbols and other internal objects
1530 if (o->is_instance() || o->is_objArray() || o->is_typeArray()) {
1531 u4 size = 1 + 2 * sizeof(address);
1532 writer()->start_sub_record(HPROF_GC_ROOT_JNI_GLOBAL, size);
1533 writer()->write_objectID(o);
1534 writer()->write_rootID(obj_p); // global ref ID
1535 writer()->end_sub_record();
1536 }
1537 };
1538
1539 // Support class used to generate HPROF_GC_ROOT_STICKY_CLASS records
1540
1541 class StickyClassDumper : public KlassClosure {
1542 private:
1543 AbstractDumpWriter* _writer;
1544 AbstractDumpWriter* writer() const { return _writer; }
1545 public:
1546 StickyClassDumper(AbstractDumpWriter* writer) {
1547 _writer = writer;
1548 }
1549 void do_klass(Klass* k) {
1550 if (k->is_instance_klass()) {
1551 InstanceKlass* ik = InstanceKlass::cast(k);
1552 u4 size = 1 + sizeof(address);
1553 writer()->start_sub_record(HPROF_GC_ROOT_STICKY_CLASS, size);
1554 writer()->write_classID(ik);
1555 writer()->end_sub_record();
1556 }
1557 }
1558 };
1559
1560 // Support class used to generate HPROF_GC_ROOT_JAVA_FRAME records.
1561
1562 class JavaStackRefDumper : public StackObj {
1563 private:
1564 AbstractDumpWriter* _writer;
1565 u4 _thread_serial_num;
1566 int _frame_num;
1567 AbstractDumpWriter* writer() const { return _writer; }
1568 public:
1569 JavaStackRefDumper(AbstractDumpWriter* writer, u4 thread_serial_num)
1570 : _writer(writer), _thread_serial_num(thread_serial_num), _frame_num(-1) // default - empty stack
1571 {
1572 }
1573
1574 void set_frame_number(int n) { _frame_num = n; }
1575
1576 void dump_java_stack_refs(StackValueCollection* values);
1577 };
1578
1579 void JavaStackRefDumper::dump_java_stack_refs(StackValueCollection* values) {
1580 for (int index = 0; index < values->size(); index++) {
1581 if (values->at(index)->type() == T_OBJECT) {
1582 oop o = values->obj_at(index)();
1583 if (o != nullptr) {
1584 u4 size = 1 + sizeof(address) + 4 + 4;
1585 writer()->start_sub_record(HPROF_GC_ROOT_JAVA_FRAME, size);
1586 writer()->write_objectID(o);
1587 writer()->write_u4(_thread_serial_num);
1588 writer()->write_u4((u4)_frame_num);
1589 writer()->end_sub_record();
1590 }
1591 }
1592 }
1593 }
1594
1595 // Class to collect, store and dump thread-related data:
1596 // - HPROF_TRACE and HPROF_FRAME records;
1597 // - HPROF_GC_ROOT_THREAD_OBJ/HPROF_GC_ROOT_JAVA_FRAME/HPROF_GC_ROOT_JNI_LOCAL subrecords.
1598 class ThreadDumper : public CHeapObj<mtInternal> {
1599 public:
1600 enum class ThreadType { Platform, MountedVirtual, UnmountedVirtual };
1601
1602 private:
1603 ThreadType _thread_type;
1604 JavaThread* _java_thread;
1605 oop _thread_oop;
1606
1607 GrowableArray<StackFrameInfo*>* _frames;
1608 // non-null if the thread is OOM thread
1609 Method* _oome_constructor;
1610 int _thread_serial_num;
1611 int _start_frame_serial_num;
1612
1613 vframe* get_top_frame() const;
1614
1615 public:
1616 static bool should_dump_pthread(JavaThread* thread) {
1617 return thread->threadObj() != nullptr && !thread->is_exiting() && !thread->is_hidden_from_external_view();
1618 }
1619
1620 static bool should_dump_vthread(oop vt) {
1621 return java_lang_VirtualThread::state(vt) != java_lang_VirtualThread::NEW
1622 && java_lang_VirtualThread::state(vt) != java_lang_VirtualThread::TERMINATED;
1623 }
1624
1625 ThreadDumper(ThreadType thread_type, JavaThread* java_thread, oop thread_oop);
1626
1627 // affects frame_count
1628 void add_oom_frame(Method* oome_constructor) {
1629 assert(_start_frame_serial_num == 0, "add_oom_frame cannot be called after init_serial_nums");
1630 _oome_constructor = oome_constructor;
1631 }
1632
1633 void init_serial_nums(volatile int* thread_counter, volatile int* frame_counter) {
1634 assert(_start_frame_serial_num == 0, "already initialized");
1635 _thread_serial_num = Atomic::fetch_then_add(thread_counter, 1);
1636 _start_frame_serial_num = Atomic::fetch_then_add(frame_counter, frame_count());
1637 }
1638
1639 bool oom_thread() const {
1640 return _oome_constructor != nullptr;
1641 }
1642
1643 int frame_count() const {
1644 return _frames->length() + (oom_thread() ? 1 : 0);
1645 }
1646
1647 u4 thread_serial_num() const {
1648 return (u4)_thread_serial_num;
1649 }
1650
1651 u4 stack_trace_serial_num() const {
1652 return (u4)(_thread_serial_num + STACK_TRACE_ID);
1653 }
1654
1655 // writes HPROF_TRACE and HPROF_FRAME records
1656 // returns number of dumped frames
1657 void dump_stack_traces(AbstractDumpWriter* writer, GrowableArray<Klass*>* klass_map);
1658
1659 // writes HPROF_GC_ROOT_THREAD_OBJ subrecord
1660 void dump_thread_obj(AbstractDumpWriter* writer);
1661
1662 // Walk the stack of the thread.
1663 // Dumps a HPROF_GC_ROOT_JAVA_FRAME subrecord for each local
1664 // Dumps a HPROF_GC_ROOT_JNI_LOCAL subrecord for each JNI local
1665 void dump_stack_refs(AbstractDumpWriter* writer);
1666
1667 };
1668
1669 ThreadDumper::ThreadDumper(ThreadType thread_type, JavaThread* java_thread, oop thread_oop)
1670 : _thread_type(thread_type), _java_thread(java_thread), _thread_oop(thread_oop),
1671 _oome_constructor(nullptr),
1672 _thread_serial_num(0), _start_frame_serial_num(0)
1673 {
1674 // sanity checks
1675 if (_thread_type == ThreadType::UnmountedVirtual) {
1676 assert(_java_thread == nullptr, "sanity");
1677 assert(_thread_oop != nullptr, "sanity");
1678 } else {
1679 assert(_java_thread != nullptr, "sanity");
1680 assert(_thread_oop != nullptr, "sanity");
1681 }
1682
1683 _frames = new (mtServiceability) GrowableArray<StackFrameInfo*>(10, mtServiceability);
1684 bool stop_at_vthread_entry = _thread_type == ThreadType::MountedVirtual;
1685
1686 // vframes are resource allocated
1687 Thread* current_thread = Thread::current();
1688 ResourceMark rm(current_thread);
1689 HandleMark hm(current_thread);
1690
1691 for (vframe* vf = get_top_frame(); vf != nullptr; vf = vf->sender()) {
1692 if (stop_at_vthread_entry && vf->is_vthread_entry()) {
1693 break;
1694 }
1695 if (vf->is_java_frame()) {
1696 javaVFrame* jvf = javaVFrame::cast(vf);
1697 _frames->append(new StackFrameInfo(jvf, false));
1698 } else {
1699 // ignore non-Java frames
1700 }
1701 }
1702 }
1703
1704 void ThreadDumper::dump_stack_traces(AbstractDumpWriter* writer, GrowableArray<Klass*>* klass_map) {
1705 assert(_thread_serial_num != 0 && _start_frame_serial_num != 0, "serial_nums are not initialized");
1706
1707 // write HPROF_FRAME records for this thread's stack trace
1708 int depth = _frames->length();
1709 int frame_serial_num = _start_frame_serial_num;
1710
1711 if (oom_thread()) {
1712 // OOM thread
1713 // write fake frame that makes it look like the thread, which caused OOME,
1714 // is in the OutOfMemoryError zero-parameter constructor
1715 int oome_serial_num = klass_map->find(_oome_constructor->method_holder());
1716 // the class serial number starts from 1
1717 assert(oome_serial_num > 0, "OutOfMemoryError class not found");
1718 DumperSupport::dump_stack_frame(writer, ++frame_serial_num, oome_serial_num, _oome_constructor, 0);
1719 depth++;
1720 }
1721
1722 for (int j = 0; j < _frames->length(); j++) {
1723 StackFrameInfo* frame = _frames->at(j);
1724 Method* m = frame->method();
1725 int class_serial_num = klass_map->find(m->method_holder());
1726 // the class serial number starts from 1
1727 assert(class_serial_num > 0, "class not found");
1728 DumperSupport::dump_stack_frame(writer, ++frame_serial_num, class_serial_num, m, frame->bci());
1729 }
1730
1731 // write HPROF_TRACE record for the thread
1732 DumperSupport::write_header(writer, HPROF_TRACE, checked_cast<u4>(3 * sizeof(u4) + depth * oopSize));
1733 writer->write_u4(stack_trace_serial_num()); // stack trace serial number
1734 writer->write_u4(thread_serial_num()); // thread serial number
1735 writer->write_u4((u4)depth); // frame count (including oom frame)
1736 for (int j = 1; j <= depth; j++) {
1737 writer->write_id(_start_frame_serial_num + j);
1738 }
1739 }
1740
1741 void ThreadDumper::dump_thread_obj(AbstractDumpWriter * writer) {
1742 assert(_thread_serial_num != 0 && _start_frame_serial_num != 0, "serial_num is not initialized");
1743
1744 u4 size = 1 + sizeof(address) + 4 + 4;
1745 writer->start_sub_record(HPROF_GC_ROOT_THREAD_OBJ, size);
1746 writer->write_objectID(_thread_oop);
1747 writer->write_u4(thread_serial_num()); // thread serial number
1748 writer->write_u4(stack_trace_serial_num()); // stack trace serial number
1749 writer->end_sub_record();
1750 }
1751
1752 void ThreadDumper::dump_stack_refs(AbstractDumpWriter * writer) {
1753 assert(_thread_serial_num != 0 && _start_frame_serial_num != 0, "serial_num is not initialized");
1754
1755 JNILocalsDumper blk(writer, thread_serial_num());
1756 if (_thread_type == ThreadType::Platform) {
1757 if (!_java_thread->has_last_Java_frame()) {
1758 // no last java frame but there may be JNI locals
1759 _java_thread->active_handles()->oops_do(&blk);
1760 return;
1761 }
1762 }
1763
1764 JavaStackRefDumper java_ref_dumper(writer, thread_serial_num());
1765
1766 // vframes are resource allocated
1767 Thread* current_thread = Thread::current();
1768 ResourceMark rm(current_thread);
1769 HandleMark hm(current_thread);
1770
1771 bool stopAtVthreadEntry = _thread_type == ThreadType::MountedVirtual;
1772 frame* last_entry_frame = nullptr;
1773 bool is_top_frame = true;
1774 int depth = 0;
1775 if (oom_thread()) {
1776 depth++;
1777 }
1778
1779 for (vframe* vf = get_top_frame(); vf != nullptr; vf = vf->sender()) {
1780 if (stopAtVthreadEntry && vf->is_vthread_entry()) {
1781 break;
1782 }
1783
1784 if (vf->is_java_frame()) {
1785 javaVFrame* jvf = javaVFrame::cast(vf);
1786 if (!(jvf->method()->is_native())) {
1787 java_ref_dumper.set_frame_number(depth);
1788 java_ref_dumper.dump_java_stack_refs(jvf->locals());
1789 java_ref_dumper.dump_java_stack_refs(jvf->expressions());
1790 } else {
1791 // native frame
1792 blk.set_frame_number(depth);
1793 if (is_top_frame) {
1794 // JNI locals for the top frame.
1795 assert(_java_thread != nullptr, "impossible for unmounted vthread");
1796 _java_thread->active_handles()->oops_do(&blk);
1797 } else {
1798 if (last_entry_frame != nullptr) {
1799 // JNI locals for the entry frame
1800 assert(last_entry_frame->is_entry_frame(), "checking");
1801 last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(&blk);
1802 }
1803 }
1804 }
1805 last_entry_frame = nullptr;
1806 // increment only for Java frames
1807 depth++;
1808 } else {
1809 // externalVFrame - for an entry frame then we report the JNI locals
1810 // when we find the corresponding javaVFrame
1811 frame* fr = vf->frame_pointer();
1812 assert(fr != nullptr, "sanity check");
1813 if (fr->is_entry_frame()) {
1814 last_entry_frame = fr;
1815 }
1816 }
1817 is_top_frame = false;
1818 }
1819 assert(depth == frame_count(), "total number of Java frames not matched");
1820 }
1821
1822 vframe* ThreadDumper::get_top_frame() const {
1823 if (_thread_type == ThreadType::UnmountedVirtual) {
1824 ContinuationWrapper cont(java_lang_VirtualThread::continuation(_thread_oop));
1825 if (cont.is_empty()) {
1826 return nullptr;
1827 }
1828 assert(!cont.is_mounted(), "sanity check");
1829 stackChunkOop chunk = cont.last_nonempty_chunk();
1830 if (chunk == nullptr || chunk->is_empty()) {
1831 return nullptr;
1832 }
1833
1834 RegisterMap reg_map(cont.continuation(), RegisterMap::UpdateMap::include);
1835 frame fr = chunk->top_frame(®_map);
1836 vframe* vf = vframe::new_vframe(&fr, ®_map, nullptr); // don't need JavaThread
1837 return vf;
1838 }
1839
1840 RegisterMap reg_map(_java_thread,
1841 RegisterMap::UpdateMap::include,
1842 RegisterMap::ProcessFrames::include,
1843 RegisterMap::WalkContinuation::skip);
1844 switch (_thread_type) {
1845 case ThreadType::Platform:
1846 if (!_java_thread->has_last_Java_frame()) {
1847 return nullptr;
1848 }
1849 return _java_thread->is_vthread_mounted()
1850 ? _java_thread->carrier_last_java_vframe(®_map)
1851 : _java_thread->platform_thread_last_java_vframe(®_map);
1852
1853 case ThreadType::MountedVirtual:
1854 return _java_thread->last_java_vframe(®_map);
1855
1856 default: // make compilers happy
1857 break;
1858 }
1859 ShouldNotReachHere();
1860 return nullptr;
1861 }
1862
1863
1864 class VM_HeapDumper;
1865
1866 // Support class using when iterating over the heap.
1867 class HeapObjectDumper : public ObjectClosure {
1868 private:
1869 AbstractDumpWriter* _writer;
1870 AbstractDumpWriter* writer() { return _writer; }
1871
1872 DumperClassCacheTable _class_cache;
1873
1874 public:
1875 HeapObjectDumper(AbstractDumpWriter* writer) {
1876 _writer = writer;
1877 }
1878
1879 // called for each object in the heap
1880 void do_object(oop o);
1881 };
1882
1883 void HeapObjectDumper::do_object(oop o) {
1884 // skip classes as these emitted as HPROF_GC_CLASS_DUMP records
1885 if (o->klass() == vmClasses::Class_klass()) {
1886 if (!java_lang_Class::is_primitive(o)) {
1887 return;
1888 }
1889 }
1890
1891 if (DumperSupport::mask_dormant_archived_object(o, nullptr) == nullptr) {
1892 return;
1893 }
1894
1895 if (o->is_instance()) {
1896 // create a HPROF_GC_INSTANCE record for each object
1897 DumperSupport::dump_instance(writer(), o, &_class_cache);
1898 } else if (o->is_objArray()) {
1899 // create a HPROF_GC_OBJ_ARRAY_DUMP record for each object array
1900 DumperSupport::dump_object_array(writer(), objArrayOop(o));
1901 } else if (o->is_typeArray()) {
1902 // create a HPROF_GC_PRIM_ARRAY_DUMP record for each type array
1903 DumperSupport::dump_prim_array(writer(), typeArrayOop(o));
1904 }
1905 }
1906
1907 // The dumper controller for parallel heap dump
1908 class DumperController : public CHeapObj<mtInternal> {
1909 private:
1910 Monitor* _lock;
1911 const uint _dumper_number;
1912 uint _complete_number;
1913
1914 public:
1915 DumperController(uint number) :
1916 _lock(new (std::nothrow) PaddedMonitor(Mutex::safepoint, "DumperController_lock")),
1917 _dumper_number(number),
1918 _complete_number(0) { }
1919
1920 ~DumperController() { delete _lock; }
1921
1922 void dumper_complete(DumpWriter* local_writer, DumpWriter* global_writer) {
1923 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
1924 _complete_number++;
1925 // propagate local error to global if any
1926 if (local_writer->has_error()) {
1927 global_writer->set_error(local_writer->error());
1928 }
1929 ml.notify();
1930 }
1931
1932 void wait_all_dumpers_complete() {
1933 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
1934 while (_complete_number != _dumper_number) {
1935 ml.wait();
1936 }
1937 }
1938 };
1939
1940 // DumpMerger merges separate dump files into a complete one
1941 class DumpMerger : public StackObj {
1942 private:
1943 DumpWriter* _writer;
1944 const char* _path;
1945 bool _has_error;
1946 int _dump_seq;
1947
1948 private:
1949 void merge_file(char* path);
1950 void merge_done();
1951 void set_error(const char* msg);
1952
1953 public:
1954 DumpMerger(const char* path, DumpWriter* writer, int dump_seq) :
1955 _writer(writer),
1956 _path(path),
1957 _has_error(_writer->has_error()),
1958 _dump_seq(dump_seq) {}
1959
1960 void do_merge();
1961 };
1962
1963 void DumpMerger::merge_done() {
1964 // Writes the HPROF_HEAP_DUMP_END record.
1965 if (!_has_error) {
1966 DumperSupport::end_of_dump(_writer);
1967 _writer->flush();
1968 }
1969 _dump_seq = 0; //reset
1970 }
1971
1972 void DumpMerger::set_error(const char* msg) {
1973 assert(msg != nullptr, "sanity check");
1974 log_error(heapdump)("%s (file: %s)", msg, _path);
1975 _writer->set_error(msg);
1976 _has_error = true;
1977 }
1978
1979 #ifdef LINUX
1980 // Merge segmented heap files via sendfile, it's more efficient than the
1981 // read+write combination, which would require transferring data to and from
1982 // user space.
1983 void DumpMerger::merge_file(char* path) {
1984 assert(!SafepointSynchronize::is_at_safepoint(), "merging happens outside safepoint");
1985 TraceTime timer("Merge segmented heap file directly", TRACETIME_LOG(Info, heapdump));
1986
1987 int segment_fd = os::open(path, O_RDONLY, 0);
1988 if (segment_fd == -1) {
1989 set_error("Can not open segmented heap file during merging");
1990 return;
1991 }
1992
1993 struct stat st;
1994 if (os::stat(path, &st) != 0) {
1995 ::close(segment_fd);
1996 set_error("Can not get segmented heap file size during merging");
1997 return;
1998 }
1999
2000 // A successful call to sendfile may write fewer bytes than requested; the
2001 // caller should be prepared to retry the call if there were unsent bytes.
2002 jlong offset = 0;
2003 while (offset < st.st_size) {
2004 int ret = os::Linux::sendfile(_writer->get_fd(), segment_fd, &offset, st.st_size);
2005 if (ret == -1) {
2006 ::close(segment_fd);
2007 set_error("Failed to merge segmented heap file");
2008 return;
2009 }
2010 }
2011
2012 // As sendfile variant does not call the write method of the global writer,
2013 // bytes_written is also incorrect for this variant, we need to explicitly
2014 // accumulate bytes_written for the global writer in this case
2015 julong accum = _writer->bytes_written() + st.st_size;
2016 _writer->set_bytes_written(accum);
2017 ::close(segment_fd);
2018 }
2019 #else
2020 // Generic implementation using read+write
2021 void DumpMerger::merge_file(char* path) {
2022 assert(!SafepointSynchronize::is_at_safepoint(), "merging happens outside safepoint");
2023 TraceTime timer("Merge segmented heap file", TRACETIME_LOG(Info, heapdump));
2024
2025 fileStream segment_fs(path, "rb");
2026 if (!segment_fs.is_open()) {
2027 set_error("Can not open segmented heap file during merging");
2028 return;
2029 }
2030
2031 jlong total = 0;
2032 size_t cnt = 0;
2033 char read_buf[4096];
2034 while ((cnt = segment_fs.read(read_buf, 1, 4096)) != 0) {
2035 _writer->write_raw(read_buf, cnt);
2036 total += cnt;
2037 }
2038
2039 _writer->flush();
2040 if (segment_fs.fileSize() != total) {
2041 set_error("Merged heap dump is incomplete");
2042 }
2043 }
2044 #endif
2045
2046 void DumpMerger::do_merge() {
2047 assert(!SafepointSynchronize::is_at_safepoint(), "merging happens outside safepoint");
2048 TraceTime timer("Merge heap files complete", TRACETIME_LOG(Info, heapdump));
2049
2050 // Since contents in segmented heap file were already zipped, we don't need to zip
2051 // them again during merging.
2052 AbstractCompressor* saved_compressor = _writer->compressor();
2053 _writer->set_compressor(nullptr);
2054
2055 // Merge the content of the remaining files into base file. Regardless of whether
2056 // the merge process is successful or not, these segmented files will be deleted.
2057 char path[JVM_MAXPATHLEN];
2058 for (int i = 0; i < _dump_seq; i++) {
2059 memset(path, 0, JVM_MAXPATHLEN);
2060 os::snprintf(path, JVM_MAXPATHLEN, "%s.p%d", _path, i);
2061 if (!_has_error) {
2062 merge_file(path);
2063 }
2064 // Delete selected segmented heap file nevertheless
2065 if (remove(path) != 0) {
2066 log_info(heapdump)("Removal of segment file (%d) failed (%d)", i, errno);
2067 }
2068 }
2069
2070 // restore compressor for further use
2071 _writer->set_compressor(saved_compressor);
2072 merge_done();
2073 }
2074
2075 // The VM operation wraps DumpMerger so that it could be performed by VM thread
2076 class VM_HeapDumpMerge : public VM_Operation {
2077 private:
2078 DumpMerger* _merger;
2079 public:
2080 VM_HeapDumpMerge(DumpMerger* merger) : _merger(merger) {}
2081 VMOp_Type type() const { return VMOp_HeapDumpMerge; }
2082 // heap dump merge could happen outside safepoint
2083 virtual bool evaluate_at_safepoint() const { return false; }
2084 void doit() {
2085 _merger->do_merge();
2086 }
2087 };
2088
2089 // The VM operation that performs the heap dump
2090 class VM_HeapDumper : public VM_GC_Operation, public WorkerTask {
2091 private:
2092 static VM_HeapDumper* _global_dumper;
2093 static DumpWriter* _global_writer;
2094 DumpWriter* _local_writer;
2095 JavaThread* _oome_thread;
2096 Method* _oome_constructor;
2097 bool _gc_before_heap_dump;
2098 GrowableArray<Klass*>* _klass_map;
2099
2100 ThreadDumper** _thread_dumpers; // platform, carrier and mounted virtual threads
2101 int _thread_dumpers_count;
2102 volatile int _thread_serial_num;
2103 volatile int _frame_serial_num;
2104
2105 volatile int _dump_seq;
2106 // parallel heap dump support
2107 uint _num_dumper_threads;
2108 DumperController* _dumper_controller;
2109 ParallelObjectIterator* _poi;
2110 // worker id of VMDumper thread.
2111 static const size_t VMDumperWorkerId = 0;
2112 // VM dumper dumps both heap and non-heap data, other dumpers dump heap-only data.
2113 static bool is_vm_dumper(uint worker_id) { return worker_id == VMDumperWorkerId; }
2114
2115 // accessors and setters
2116 static VM_HeapDumper* dumper() { assert(_global_dumper != nullptr, "Error"); return _global_dumper; }
2117 static DumpWriter* writer() { assert(_global_writer != nullptr, "Error"); return _global_writer; }
2118
2119 void set_global_dumper() {
2120 assert(_global_dumper == nullptr, "Error");
2121 _global_dumper = this;
2122 }
2123 void set_global_writer() {
2124 assert(_global_writer == nullptr, "Error");
2125 _global_writer = _local_writer;
2126 }
2127 void clear_global_dumper() { _global_dumper = nullptr; }
2128 void clear_global_writer() { _global_writer = nullptr; }
2129
2130 bool skip_operation() const;
2131
2132 // create dump writer for every parallel dump thread
2133 DumpWriter* create_local_writer();
2134
2135 // writes a HPROF_LOAD_CLASS record
2136 static void do_load_class(Klass* k);
2137
2138 // writes a HPROF_GC_CLASS_DUMP record for the given class
2139 static void do_class_dump(Klass* k);
2140
2141 // HPROF_GC_ROOT_THREAD_OBJ records for platform and mounted virtual threads
2142 void dump_threads();
2143
2144 void add_class_serial_number(Klass* k, int serial_num) {
2145 _klass_map->at_put_grow(serial_num, k);
2146 }
2147
2148 bool is_oom_thread(JavaThread* thread) const {
2149 return thread == _oome_thread && _oome_constructor != nullptr;
2150 }
2151
2152 // HPROF_TRACE and HPROF_FRAME records for platform and mounted virtual threads
2153 void dump_stack_traces();
2154
2155 public:
2156 VM_HeapDumper(DumpWriter* writer, bool gc_before_heap_dump, bool oome, uint num_dump_threads) :
2157 VM_GC_Operation(0 /* total collections, dummy, ignored */,
2158 GCCause::_heap_dump /* GC Cause */,
2159 0 /* total full collections, dummy, ignored */,
2160 gc_before_heap_dump),
2161 WorkerTask("dump heap") {
2162 _local_writer = writer;
2163 _gc_before_heap_dump = gc_before_heap_dump;
2164 _klass_map = new (mtServiceability) GrowableArray<Klass*>(INITIAL_CLASS_COUNT, mtServiceability);
2165
2166 _thread_dumpers = nullptr;
2167 _thread_dumpers_count = 0;
2168 _thread_serial_num = 1;
2169 _frame_serial_num = 1;
2170
2171 _dump_seq = 0;
2172 _num_dumper_threads = num_dump_threads;
2173 _dumper_controller = nullptr;
2174 _poi = nullptr;
2175 if (oome) {
2176 assert(!Thread::current()->is_VM_thread(), "Dump from OutOfMemoryError cannot be called by the VMThread");
2177 // get OutOfMemoryError zero-parameter constructor
2178 InstanceKlass* oome_ik = vmClasses::OutOfMemoryError_klass();
2179 _oome_constructor = oome_ik->find_method(vmSymbols::object_initializer_name(),
2180 vmSymbols::void_method_signature());
2181 // get thread throwing OOME when generating the heap dump at OOME
2182 _oome_thread = JavaThread::current();
2183 } else {
2184 _oome_thread = nullptr;
2185 _oome_constructor = nullptr;
2186 }
2187 }
2188
2189 ~VM_HeapDumper() {
2190 if (_thread_dumpers != nullptr) {
2191 for (int i = 0; i < _thread_dumpers_count; i++) {
2192 delete _thread_dumpers[i];
2193 }
2194 FREE_C_HEAP_ARRAY(ThreadDumper*, _thread_dumpers);
2195 }
2196
2197 if (_dumper_controller != nullptr) {
2198 delete _dumper_controller;
2199 _dumper_controller = nullptr;
2200 }
2201 delete _klass_map;
2202 }
2203 int dump_seq() { return _dump_seq; }
2204 bool is_parallel_dump() { return _num_dumper_threads > 1; }
2205 bool can_parallel_dump(WorkerThreads* workers);
2206
2207 VMOp_Type type() const { return VMOp_HeapDumper; }
2208 virtual bool doit_prologue();
2209 void doit();
2210 void work(uint worker_id);
2211 };
2212
2213 VM_HeapDumper* VM_HeapDumper::_global_dumper = nullptr;
2214 DumpWriter* VM_HeapDumper::_global_writer = nullptr;
2215
2216 bool VM_HeapDumper::skip_operation() const {
2217 return false;
2218 }
2219
2220 // fixes up the current dump record and writes HPROF_HEAP_DUMP_END record
2221 void DumperSupport::end_of_dump(AbstractDumpWriter* writer) {
2222 writer->finish_dump_segment();
2223
2224 writer->write_u1(HPROF_HEAP_DUMP_END);
2225 writer->write_u4(0);
2226 writer->write_u4(0);
2227 }
2228
2229 // writes a HPROF_LOAD_CLASS record for the class
2230 void VM_HeapDumper::do_load_class(Klass* k) {
2231 static u4 class_serial_num = 0;
2232
2233 // len of HPROF_LOAD_CLASS record
2234 u4 remaining = 2*oopSize + 2*sizeof(u4);
2235
2236 DumperSupport::write_header(writer(), HPROF_LOAD_CLASS, remaining);
2237
2238 // class serial number is just a number
2239 writer()->write_u4(++class_serial_num);
2240
2241 // class ID
2242 writer()->write_classID(k);
2243
2244 // add the Klass* and class serial number pair
2245 dumper()->add_class_serial_number(k, class_serial_num);
2246
2247 writer()->write_u4(STACK_TRACE_ID);
2248
2249 // class name ID
2250 Symbol* name = k->name();
2251 writer()->write_symbolID(name);
2252 }
2253
2254 // writes a HPROF_GC_CLASS_DUMP record for the given class
2255 void VM_HeapDumper::do_class_dump(Klass* k) {
2256 if (k->is_instance_klass()) {
2257 DumperSupport::dump_instance_class(writer(), k);
2258 } else {
2259 DumperSupport::dump_array_class(writer(), k);
2260 }
2261 }
2262
2263 // Write a HPROF_GC_ROOT_THREAD_OBJ record for platform/carrier and mounted virtual threads.
2264 // Then walk the stack so that locals and JNI locals are dumped.
2265 void VM_HeapDumper::dump_threads() {
2266 for (int i = 0; i < _thread_dumpers_count; i++) {
2267 _thread_dumpers[i]->dump_thread_obj(writer());
2268 _thread_dumpers[i]->dump_stack_refs(writer());
2269 }
2270 }
2271
2272 bool VM_HeapDumper::doit_prologue() {
2273 if (_gc_before_heap_dump && UseZGC) {
2274 // ZGC cannot perform a synchronous GC cycle from within the VM thread.
2275 // So ZCollectedHeap::collect_as_vm_thread() is a noop. To respect the
2276 // _gc_before_heap_dump flag a synchronous GC cycle is performed from
2277 // the caller thread in the prologue.
2278 Universe::heap()->collect(GCCause::_heap_dump);
2279 }
2280 return VM_GC_Operation::doit_prologue();
2281 }
2282
2283 bool VM_HeapDumper::can_parallel_dump(WorkerThreads* workers) {
2284 bool can_parallel = true;
2285 uint num_active_workers = workers != nullptr ? workers->active_workers() : 0;
2286 uint num_requested_dump_threads = _num_dumper_threads;
2287 // check if we can dump in parallel based on requested and active threads
2288 if (num_active_workers <= 1 || num_requested_dump_threads <= 1) {
2289 _num_dumper_threads = 1;
2290 can_parallel = false;
2291 } else {
2292 // check if we have extra path room to accommodate segmented heap files
2293 const char* base_path = writer()->get_file_path();
2294 assert(base_path != nullptr, "sanity check");
2295 if ((strlen(base_path) + 7/*.p\d\d\d\d\0*/) >= JVM_MAXPATHLEN) {
2296 _num_dumper_threads = 1;
2297 can_parallel = false;
2298 } else {
2299 _num_dumper_threads = clamp(num_requested_dump_threads, 2U, num_active_workers);
2300 }
2301 }
2302
2303 log_info(heapdump)("Requested dump threads %u, active dump threads %u, "
2304 "actual dump threads %u, parallelism %s",
2305 num_requested_dump_threads, num_active_workers,
2306 _num_dumper_threads, can_parallel ? "true" : "false");
2307 return can_parallel;
2308 }
2309
2310 // The VM operation that dumps the heap. The dump consists of the following
2311 // records:
2312 //
2313 // HPROF_HEADER
2314 // [HPROF_UTF8]*
2315 // [HPROF_LOAD_CLASS]*
2316 // [[HPROF_FRAME]*|HPROF_TRACE]*
2317 // [HPROF_GC_CLASS_DUMP]*
2318 // [HPROF_HEAP_DUMP_SEGMENT]*
2319 // HPROF_HEAP_DUMP_END
2320 //
2321 // The HPROF_TRACE records represent the stack traces where the heap dump
2322 // is generated and a "dummy trace" record which does not include
2323 // any frames. The dummy trace record is used to be referenced as the
2324 // unknown object alloc site.
2325 //
2326 // Each HPROF_HEAP_DUMP_SEGMENT record has a length followed by sub-records.
2327 // To allow the heap dump be generated in a single pass we remember the position
2328 // of the dump length and fix it up after all sub-records have been written.
2329 // To generate the sub-records we iterate over the heap, writing
2330 // HPROF_GC_INSTANCE_DUMP, HPROF_GC_OBJ_ARRAY_DUMP, and HPROF_GC_PRIM_ARRAY_DUMP
2331 // records as we go. Once that is done we write records for some of the GC
2332 // roots.
2333
2334 void VM_HeapDumper::doit() {
2335
2336 CollectedHeap* ch = Universe::heap();
2337
2338 ch->ensure_parsability(false); // must happen, even if collection does
2339 // not happen (e.g. due to GCLocker)
2340
2341 if (_gc_before_heap_dump) {
2342 if (GCLocker::is_active()) {
2343 warning("GC locker is held; pre-heapdump GC was skipped");
2344 } else {
2345 ch->collect_as_vm_thread(GCCause::_heap_dump);
2346 }
2347 }
2348
2349 // At this point we should be the only dumper active, so
2350 // the following should be safe.
2351 set_global_dumper();
2352 set_global_writer();
2353
2354 WorkerThreads* workers = ch->safepoint_workers();
2355 if (!can_parallel_dump(workers)) {
2356 work(VMDumperWorkerId);
2357 } else {
2358 uint heap_only_dumper_threads = _num_dumper_threads - 1 /* VMDumper thread */;
2359 _dumper_controller = new (std::nothrow) DumperController(heap_only_dumper_threads);
2360 ParallelObjectIterator poi(_num_dumper_threads);
2361 _poi = &poi;
2362 workers->run_task(this, _num_dumper_threads);
2363 _poi = nullptr;
2364 }
2365
2366 // Now we clear the global variables, so that a future dumper can run.
2367 clear_global_dumper();
2368 clear_global_writer();
2369 }
2370
2371 // prepare DumpWriter for every parallel dump thread
2372 DumpWriter* VM_HeapDumper::create_local_writer() {
2373 char* path = NEW_RESOURCE_ARRAY(char, JVM_MAXPATHLEN);
2374 memset(path, 0, JVM_MAXPATHLEN);
2375
2376 // generate segmented heap file path
2377 const char* base_path = writer()->get_file_path();
2378 // share global compressor, local DumpWriter is not responsible for its life cycle
2379 AbstractCompressor* compressor = writer()->compressor();
2380 int seq = Atomic::fetch_then_add(&_dump_seq, 1);
2381 os::snprintf(path, JVM_MAXPATHLEN, "%s.p%d", base_path, seq);
2382
2383 // create corresponding writer for that
2384 DumpWriter* local_writer = new DumpWriter(path, writer()->is_overwrite(), compressor);
2385 return local_writer;
2386 }
2387
2388 void VM_HeapDumper::work(uint worker_id) {
2389 // VM Dumper works on all non-heap data dumping and part of heap iteration.
2390 if (is_vm_dumper(worker_id)) {
2391 TraceTime timer("Dump non-objects", TRACETIME_LOG(Info, heapdump));
2392 // Write the file header - we always use 1.0.2
2393 const char* header = "JAVA PROFILE 1.0.2";
2394
2395 // header is few bytes long - no chance to overflow int
2396 writer()->write_raw(header, strlen(header) + 1); // NUL terminated
2397 writer()->write_u4(oopSize);
2398 // timestamp is current time in ms
2399 writer()->write_u8(os::javaTimeMillis());
2400 // HPROF_UTF8 records
2401 SymbolTableDumper sym_dumper(writer());
2402 SymbolTable::symbols_do(&sym_dumper);
2403
2404 // write HPROF_LOAD_CLASS records
2405 {
2406 LockedClassesDo locked_load_classes(&do_load_class);
2407 ClassLoaderDataGraph::classes_do(&locked_load_classes);
2408 }
2409
2410 // write HPROF_FRAME and HPROF_TRACE records
2411 // this must be called after _klass_map is built when iterating the classes above.
2412 dump_stack_traces();
2413
2414 // HPROF_HEAP_DUMP/HPROF_HEAP_DUMP_SEGMENT starts here
2415
2416 // Writes HPROF_GC_CLASS_DUMP records
2417 {
2418 LockedClassesDo locked_dump_class(&do_class_dump);
2419 ClassLoaderDataGraph::classes_do(&locked_dump_class);
2420 }
2421
2422 // HPROF_GC_ROOT_THREAD_OBJ + frames + jni locals
2423 dump_threads();
2424
2425 // HPROF_GC_ROOT_JNI_GLOBAL
2426 JNIGlobalsDumper jni_dumper(writer());
2427 JNIHandles::oops_do(&jni_dumper);
2428 // technically not jni roots, but global roots
2429 // for things like preallocated throwable backtraces
2430 Universe::vm_global()->oops_do(&jni_dumper);
2431 // HPROF_GC_ROOT_STICKY_CLASS
2432 // These should be classes in the null class loader data, and not all classes
2433 // if !ClassUnloading
2434 StickyClassDumper class_dumper(writer());
2435 ClassLoaderData::the_null_class_loader_data()->classes_do(&class_dumper);
2436 }
2437
2438 // Heap iteration.
2439 // writes HPROF_GC_INSTANCE_DUMP records.
2440 // After each sub-record is written check_segment_length will be invoked
2441 // to check if the current segment exceeds a threshold. If so, a new
2442 // segment is started.
2443 // The HPROF_GC_CLASS_DUMP and HPROF_GC_INSTANCE_DUMP are the vast bulk
2444 // of the heap dump.
2445 if (!is_parallel_dump()) {
2446 assert(is_vm_dumper(worker_id), "must be");
2447 // == Serial dump
2448 ResourceMark rm;
2449 TraceTime timer("Dump heap objects", TRACETIME_LOG(Info, heapdump));
2450 HeapObjectDumper obj_dumper(writer());
2451 Universe::heap()->object_iterate(&obj_dumper);
2452 writer()->finish_dump_segment();
2453 // Writes the HPROF_HEAP_DUMP_END record because merge does not happen in serial dump
2454 DumperSupport::end_of_dump(writer());
2455 writer()->flush();
2456 } else {
2457 // == Parallel dump
2458 ResourceMark rm;
2459 TraceTime timer("Dump heap objects in parallel", TRACETIME_LOG(Info, heapdump));
2460 DumpWriter* local_writer = is_vm_dumper(worker_id) ? writer() : create_local_writer();
2461 if (!local_writer->has_error()) {
2462 HeapObjectDumper obj_dumper(local_writer);
2463 _poi->object_iterate(&obj_dumper, worker_id);
2464 local_writer->finish_dump_segment();
2465 local_writer->flush();
2466 }
2467 if (is_vm_dumper(worker_id)) {
2468 _dumper_controller->wait_all_dumpers_complete();
2469 } else {
2470 _dumper_controller->dumper_complete(local_writer, writer());
2471 delete local_writer;
2472 return;
2473 }
2474 }
2475 // At this point, all fragments of the heapdump have been written to separate files.
2476 // We need to merge them into a complete heapdump and write HPROF_HEAP_DUMP_END at that time.
2477 }
2478
2479 void VM_HeapDumper::dump_stack_traces() {
2480 // write a HPROF_TRACE record without any frames to be referenced as object alloc sites
2481 DumperSupport::write_header(writer(), HPROF_TRACE, 3 * sizeof(u4));
2482 writer()->write_u4((u4)STACK_TRACE_ID);
2483 writer()->write_u4(0); // thread number
2484 writer()->write_u4(0); // frame count
2485
2486 // max number if every platform thread is carrier with mounted virtual thread
2487 _thread_dumpers = NEW_C_HEAP_ARRAY(ThreadDumper*, Threads::number_of_threads() * 2, mtInternal);
2488
2489 for (JavaThreadIteratorWithHandle jtiwh; JavaThread * thread = jtiwh.next(); ) {
2490 if (ThreadDumper::should_dump_pthread(thread)) {
2491 bool add_oom_frame = is_oom_thread(thread);
2492
2493 oop mounted_vt = thread->is_vthread_mounted() ? thread->vthread() : nullptr;
2494 if (mounted_vt != nullptr && !ThreadDumper::should_dump_vthread(mounted_vt)) {
2495 mounted_vt = nullptr;
2496 }
2497
2498 // mounted vthread (if any)
2499 if (mounted_vt != nullptr) {
2500 ThreadDumper* thread_dumper = new ThreadDumper(ThreadDumper::ThreadType::MountedVirtual, thread, mounted_vt);
2501 _thread_dumpers[_thread_dumpers_count++] = thread_dumper;
2502 if (add_oom_frame) {
2503 thread_dumper->add_oom_frame(_oome_constructor);
2504 // we add oom frame to the VT stack, don't add it to the carrier thread stack
2505 add_oom_frame = false;
2506 }
2507 thread_dumper->init_serial_nums(&_thread_serial_num, &_frame_serial_num);
2508 thread_dumper->dump_stack_traces(writer(), _klass_map);
2509 }
2510
2511 // platform or carrier thread
2512 ThreadDumper* thread_dumper = new ThreadDumper(ThreadDumper::ThreadType::Platform, thread, thread->threadObj());
2513 _thread_dumpers[_thread_dumpers_count++] = thread_dumper;
2514 if (add_oom_frame) {
2515 thread_dumper->add_oom_frame(_oome_constructor);
2516 }
2517 thread_dumper->init_serial_nums(&_thread_serial_num, &_frame_serial_num);
2518 thread_dumper->dump_stack_traces(writer(), _klass_map);
2519 }
2520 }
2521 }
2522
2523 // dump the heap to given path.
2524 int HeapDumper::dump(const char* path, outputStream* out, int compression, bool overwrite, uint num_dump_threads) {
2525 assert(path != nullptr && strlen(path) > 0, "path missing");
2526
2527 // print message in interactive case
2528 if (out != nullptr) {
2529 out->print_cr("Dumping heap to %s ...", path);
2530 timer()->start();
2531 }
2532 // create JFR event
2533 EventHeapDump event;
2534
2535 AbstractCompressor* compressor = nullptr;
2536
2537 if (compression > 0) {
2538 compressor = new (std::nothrow) GZipCompressor(compression);
2539
2540 if (compressor == nullptr) {
2541 set_error("Could not allocate gzip compressor");
2542 return -1;
2543 }
2544 }
2545
2546 DumpWriter writer(path, overwrite, compressor);
2547
2548 if (writer.error() != nullptr) {
2549 set_error(writer.error());
2550 if (out != nullptr) {
2551 out->print_cr("Unable to create %s: %s", path,
2552 (error() != nullptr) ? error() : "reason unknown");
2553 }
2554 return -1;
2555 }
2556
2557 // generate the segmented heap dump into separate files
2558 VM_HeapDumper dumper(&writer, _gc_before_heap_dump, _oome, num_dump_threads);
2559 VMThread::execute(&dumper);
2560
2561 // record any error that the writer may have encountered
2562 set_error(writer.error());
2563
2564 // For serial dump, once VM_HeapDumper completes, the whole heap dump process
2565 // is done, no further phases needed. For parallel dump, the whole heap dump
2566 // process is done in two phases
2567 //
2568 // Phase 1: Concurrent threads directly write heap data to multiple heap files.
2569 // This is done by VM_HeapDumper, which is performed within safepoint.
2570 //
2571 // Phase 2: Merge multiple heap files into one complete heap dump file.
2572 // This is done by DumpMerger, which is performed outside safepoint
2573 if (dumper.is_parallel_dump()) {
2574 DumpMerger merger(path, &writer, dumper.dump_seq());
2575 Thread* current_thread = Thread::current();
2576 if (current_thread->is_AttachListener_thread()) {
2577 // perform heapdump file merge operation in the current thread prevents us
2578 // from occupying the VM Thread, which in turn affects the occurrence of
2579 // GC and other VM operations.
2580 merger.do_merge();
2581 } else {
2582 // otherwise, performs it by VM thread
2583 VM_HeapDumpMerge op(&merger);
2584 VMThread::execute(&op);
2585 }
2586 set_error(writer.error());
2587 }
2588
2589 // emit JFR event
2590 if (error() == nullptr) {
2591 event.set_destination(path);
2592 event.set_gcBeforeDump(_gc_before_heap_dump);
2593 event.set_size(writer.bytes_written());
2594 event.set_onOutOfMemoryError(_oome);
2595 event.set_overwrite(overwrite);
2596 event.set_compression(compression);
2597 event.commit();
2598 } else {
2599 log_debug(cds, heap)("Error %s while dumping heap", error());
2600 }
2601
2602 // print message in interactive case
2603 if (out != nullptr) {
2604 timer()->stop();
2605 if (error() == nullptr) {
2606 out->print_cr("Heap dump file created [" JULONG_FORMAT " bytes in %3.3f secs]",
2607 writer.bytes_written(), timer()->seconds());
2608 } else {
2609 out->print_cr("Dump file is incomplete: %s", writer.error());
2610 }
2611 }
2612
2613 if (compressor != nullptr) {
2614 delete compressor;
2615 }
2616 return (writer.error() == nullptr) ? 0 : -1;
2617 }
2618
2619 // stop timer (if still active), and free any error string we might be holding
2620 HeapDumper::~HeapDumper() {
2621 if (timer()->is_active()) {
2622 timer()->stop();
2623 }
2624 set_error(nullptr);
2625 }
2626
2627
2628 // returns the error string (resource allocated), or null
2629 char* HeapDumper::error_as_C_string() const {
2630 if (error() != nullptr) {
2631 char* str = NEW_RESOURCE_ARRAY(char, strlen(error())+1);
2632 strcpy(str, error());
2633 return str;
2634 } else {
2635 return nullptr;
2636 }
2637 }
2638
2639 // set the error string
2640 void HeapDumper::set_error(char const* error) {
2641 if (_error != nullptr) {
2642 os::free(_error);
2643 }
2644 if (error == nullptr) {
2645 _error = nullptr;
2646 } else {
2647 _error = os::strdup(error);
2648 assert(_error != nullptr, "allocation failure");
2649 }
2650 }
2651
2652 // Called by out-of-memory error reporting by a single Java thread
2653 // outside of a JVM safepoint
2654 void HeapDumper::dump_heap_from_oome() {
2655 HeapDumper::dump_heap(true);
2656 }
2657
2658 // Called by error reporting by a single Java thread outside of a JVM safepoint,
2659 // or by heap dumping by the VM thread during a (GC) safepoint. Thus, these various
2660 // callers are strictly serialized and guaranteed not to interfere below. For more
2661 // general use, however, this method will need modification to prevent
2662 // inteference when updating the static variables base_path and dump_file_seq below.
2663 void HeapDumper::dump_heap() {
2664 HeapDumper::dump_heap(false);
2665 }
2666
2667 void HeapDumper::dump_heap(bool oome) {
2668 static char base_path[JVM_MAXPATHLEN] = {'\0'};
2669 static uint dump_file_seq = 0;
2670 char* my_path;
2671 const int max_digit_chars = 20;
2672
2673 const char* dump_file_name = "java_pid";
2674 const char* dump_file_ext = HeapDumpGzipLevel > 0 ? ".hprof.gz" : ".hprof";
2675
2676 // The dump file defaults to java_pid<pid>.hprof in the current working
2677 // directory. HeapDumpPath=<file> can be used to specify an alternative
2678 // dump file name or a directory where dump file is created.
2679 if (dump_file_seq == 0) { // first time in, we initialize base_path
2680 // Calculate potentially longest base path and check if we have enough
2681 // allocated statically.
2682 const size_t total_length =
2683 (HeapDumpPath == nullptr ? 0 : strlen(HeapDumpPath)) +
2684 strlen(os::file_separator()) + max_digit_chars +
2685 strlen(dump_file_name) + strlen(dump_file_ext) + 1;
2686 if (total_length > sizeof(base_path)) {
2687 warning("Cannot create heap dump file. HeapDumpPath is too long.");
2688 return;
2689 }
2690
2691 bool use_default_filename = true;
2692 if (HeapDumpPath == nullptr || HeapDumpPath[0] == '\0') {
2693 // HeapDumpPath=<file> not specified
2694 } else {
2695 strcpy(base_path, HeapDumpPath);
2696 // check if the path is a directory (must exist)
2697 DIR* dir = os::opendir(base_path);
2698 if (dir == nullptr) {
2699 use_default_filename = false;
2700 } else {
2701 // HeapDumpPath specified a directory. We append a file separator
2702 // (if needed).
2703 os::closedir(dir);
2704 size_t fs_len = strlen(os::file_separator());
2705 if (strlen(base_path) >= fs_len) {
2706 char* end = base_path;
2707 end += (strlen(base_path) - fs_len);
2708 if (strcmp(end, os::file_separator()) != 0) {
2709 strcat(base_path, os::file_separator());
2710 }
2711 }
2712 }
2713 }
2714 // If HeapDumpPath wasn't a file name then we append the default name
2715 if (use_default_filename) {
2716 const size_t dlen = strlen(base_path); // if heap dump dir specified
2717 jio_snprintf(&base_path[dlen], sizeof(base_path)-dlen, "%s%d%s",
2718 dump_file_name, os::current_process_id(), dump_file_ext);
2719 }
2720 const size_t len = strlen(base_path) + 1;
2721 my_path = (char*)os::malloc(len, mtInternal);
2722 if (my_path == nullptr) {
2723 warning("Cannot create heap dump file. Out of system memory.");
2724 return;
2725 }
2726 strncpy(my_path, base_path, len);
2727 } else {
2728 // Append a sequence number id for dumps following the first
2729 const size_t len = strlen(base_path) + max_digit_chars + 2; // for '.' and \0
2730 my_path = (char*)os::malloc(len, mtInternal);
2731 if (my_path == nullptr) {
2732 warning("Cannot create heap dump file. Out of system memory.");
2733 return;
2734 }
2735 jio_snprintf(my_path, len, "%s.%d", base_path, dump_file_seq);
2736 }
2737 dump_file_seq++; // increment seq number for next time we dump
2738
2739 HeapDumper dumper(false /* no GC before heap dump */,
2740 oome /* pass along out-of-memory-error flag */);
2741 dumper.dump(my_path, tty, HeapDumpGzipLevel);
2742 os::free(my_path);
2743 }