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