1 /*
   2  * Copyright (c) 2005, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/symbolTable.hpp"
  27 #include "classfile/systemDictionary.hpp"
  28 #include "classfile/vmSymbols.hpp"
  29 #include "gc/shared/gcLocker.inline.hpp"
  30 #include "gc/shared/genCollectedHeap.hpp"
  31 #include "gc/shared/vmGCOperations.hpp"
  32 #include "memory/resourceArea.hpp"
  33 #include "memory/universe.hpp"
  34 #include "oops/objArrayKlass.hpp"
  35 #include "oops/objArrayOop.inline.hpp"
  36 #include "oops/oop.inline.hpp"
  37 #include "prims/jvm.h"
  38 #include "runtime/javaCalls.hpp"
  39 #include "runtime/jniHandles.hpp"
  40 #include "runtime/os.hpp"
  41 #include "runtime/reflectionUtils.hpp"
  42 #include "runtime/thread.inline.hpp"
  43 #include "runtime/threadSMR.hpp"
  44 #include "runtime/vframe.hpp"
  45 #include "runtime/vmThread.hpp"
  46 #include "runtime/vm_operations.hpp"
  47 #include "services/heapDumper.hpp"
  48 #include "services/threadService.hpp"
  49 #include "utilities/macros.hpp"
  50 #include "utilities/ostream.hpp"
  51 #if INCLUDE_ALL_GCS
  52 #include "gc/parallel/parallelScavengeHeap.hpp"
  53 #endif // INCLUDE_ALL_GCS
  54 
  55 /*
  56  * HPROF binary format - description copied from:
  57  *   src/share/demo/jvmti/hprof/hprof_io.c
  58  *
  59  *
  60  *  header    "JAVA PROFILE 1.0.2" (0-terminated)
  61  *
  62  *  u4        size of identifiers. Identifiers are used to represent
  63  *            UTF8 strings, objects, stack traces, etc. They usually
  64  *            have the same size as host pointers. For example, on
  65  *            Solaris and Win32, the size is 4.
  66  * u4         high word
  67  * u4         low word    number of milliseconds since 0:00 GMT, 1/1/70
  68  * [record]*  a sequence of records.
  69  *
  70  *
  71  * Record format:
  72  *
  73  * u1         a TAG denoting the type of the record
  74  * u4         number of *microseconds* since the time stamp in the
  75  *            header. (wraps around in a little more than an hour)
  76  * u4         number of bytes *remaining* in the record. Note that
  77  *            this number excludes the tag and the length field itself.
  78  * [u1]*      BODY of the record (a sequence of bytes)
  79  *
  80  *
  81  * The following TAGs are supported:
  82  *
  83  * TAG           BODY       notes
  84  *----------------------------------------------------------
  85  * HPROF_UTF8               a UTF8-encoded name
  86  *
  87  *               id         name ID
  88  *               [u1]*      UTF8 characters (no trailing zero)
  89  *
  90  * HPROF_LOAD_CLASS         a newly loaded class
  91  *
  92  *                u4        class serial number (> 0)
  93  *                id        class object ID
  94  *                u4        stack trace serial number
  95  *                id        class name ID
  96  *
  97  * HPROF_UNLOAD_CLASS       an unloading class
  98  *
  99  *                u4        class serial_number
 100  *
 101  * HPROF_FRAME              a Java stack frame
 102  *
 103  *                id        stack frame ID
 104  *                id        method name ID
 105  *                id        method signature ID
 106  *                id        source file name ID
 107  *                u4        class serial number
 108  *                i4        line number. >0: normal
 109  *                                       -1: unknown
 110  *                                       -2: compiled method
 111  *                                       -3: native method
 112  *
 113  * HPROF_TRACE              a Java stack trace
 114  *
 115  *               u4         stack trace serial number
 116  *               u4         thread serial number
 117  *               u4         number of frames
 118  *               [id]*      stack frame IDs
 119  *
 120  *
 121  * HPROF_ALLOC_SITES        a set of heap allocation sites, obtained after GC
 122  *
 123  *               u2         flags 0x0001: incremental vs. complete
 124  *                                0x0002: sorted by allocation vs. live
 125  *                                0x0004: whether to force a GC
 126  *               u4         cutoff ratio
 127  *               u4         total live bytes
 128  *               u4         total live instances
 129  *               u8         total bytes allocated
 130  *               u8         total instances allocated
 131  *               u4         number of sites that follow
 132  *               [u1        is_array: 0:  normal object
 133  *                                    2:  object array
 134  *                                    4:  boolean array
 135  *                                    5:  char array
 136  *                                    6:  float array
 137  *                                    7:  double array
 138  *                                    8:  byte array
 139  *                                    9:  short array
 140  *                                    10: int array
 141  *                                    11: long array
 142  *                u4        class serial number (may be zero during startup)
 143  *                u4        stack trace serial number
 144  *                u4        number of bytes alive
 145  *                u4        number of instances alive
 146  *                u4        number of bytes allocated
 147  *                u4]*      number of instance allocated
 148  *
 149  * HPROF_START_THREAD       a newly started thread.
 150  *
 151  *               u4         thread serial number (> 0)
 152  *               id         thread object ID
 153  *               u4         stack trace serial number
 154  *               id         thread name ID
 155  *               id         thread group name ID
 156  *               id         thread group parent name ID
 157  *
 158  * HPROF_END_THREAD         a terminating thread.
 159  *
 160  *               u4         thread serial number
 161  *
 162  * HPROF_HEAP_SUMMARY       heap summary
 163  *
 164  *               u4         total live bytes
 165  *               u4         total live instances
 166  *               u8         total bytes allocated
 167  *               u8         total instances allocated
 168  *
 169  * HPROF_HEAP_DUMP          denote a heap dump
 170  *
 171  *               [heap dump sub-records]*
 172  *
 173  *                          There are four kinds of heap dump sub-records:
 174  *
 175  *               u1         sub-record type
 176  *
 177  *               HPROF_GC_ROOT_UNKNOWN         unknown root
 178  *
 179  *                          id         object ID
 180  *
 181  *               HPROF_GC_ROOT_THREAD_OBJ      thread object
 182  *
 183  *                          id         thread object ID  (may be 0 for a
 184  *                                     thread newly attached through JNI)
 185  *                          u4         thread sequence number
 186  *                          u4         stack trace sequence number
 187  *
 188  *               HPROF_GC_ROOT_JNI_GLOBAL      JNI global ref root
 189  *
 190  *                          id         object ID
 191  *                          id         JNI global ref ID
 192  *
 193  *               HPROF_GC_ROOT_JNI_LOCAL       JNI local ref
 194  *
 195  *                          id         object ID
 196  *                          u4         thread serial number
 197  *                          u4         frame # in stack trace (-1 for empty)
 198  *
 199  *               HPROF_GC_ROOT_JAVA_FRAME      Java stack frame
 200  *
 201  *                          id         object ID
 202  *                          u4         thread serial number
 203  *                          u4         frame # in stack trace (-1 for empty)
 204  *
 205  *               HPROF_GC_ROOT_NATIVE_STACK    Native stack
 206  *
 207  *                          id         object ID
 208  *                          u4         thread serial number
 209  *
 210  *               HPROF_GC_ROOT_STICKY_CLASS    System class
 211  *
 212  *                          id         object ID
 213  *
 214  *               HPROF_GC_ROOT_THREAD_BLOCK    Reference from thread block
 215  *
 216  *                          id         object ID
 217  *                          u4         thread serial number
 218  *
 219  *               HPROF_GC_ROOT_MONITOR_USED    Busy monitor
 220  *
 221  *                          id         object ID
 222  *
 223  *               HPROF_GC_CLASS_DUMP           dump of a class object
 224  *
 225  *                          id         class object ID
 226  *                          u4         stack trace serial number
 227  *                          id         super class object ID
 228  *                          id         class loader object ID
 229  *                          id         signers object ID
 230  *                          id         protection domain object ID
 231  *                          id         reserved
 232  *                          id         reserved
 233  *
 234  *                          u4         instance size (in bytes)
 235  *
 236  *                          u2         size of constant pool
 237  *                          [u2,       constant pool index,
 238  *                           ty,       type
 239  *                                     2:  object
 240  *                                     4:  boolean
 241  *                                     5:  char
 242  *                                     6:  float
 243  *                                     7:  double
 244  *                                     8:  byte
 245  *                                     9:  short
 246  *                                     10: int
 247  *                                     11: long
 248  *                           vl]*      and value
 249  *
 250  *                          u2         number of static fields
 251  *                          [id,       static field name,
 252  *                           ty,       type,
 253  *                           vl]*      and value
 254  *
 255  *                          u2         number of inst. fields (not inc. super)
 256  *                          [id,       instance field name,
 257  *                           ty]*      type
 258  *
 259  *               HPROF_GC_INSTANCE_DUMP        dump of a normal object
 260  *
 261  *                          id         object ID
 262  *                          u4         stack trace serial number
 263  *                          id         class object ID
 264  *                          u4         number of bytes that follow
 265  *                          [vl]*      instance field values (class, followed
 266  *                                     by super, super's super ...)
 267  *
 268  *               HPROF_GC_OBJ_ARRAY_DUMP       dump of an object array
 269  *
 270  *                          id         array object ID
 271  *                          u4         stack trace serial number
 272  *                          u4         number of elements
 273  *                          id         array class ID
 274  *                          [id]*      elements
 275  *
 276  *               HPROF_GC_PRIM_ARRAY_DUMP      dump of a primitive array
 277  *
 278  *                          id         array object ID
 279  *                          u4         stack trace serial number
 280  *                          u4         number of elements
 281  *                          u1         element type
 282  *                                     4:  boolean array
 283  *                                     5:  char array
 284  *                                     6:  float array
 285  *                                     7:  double array
 286  *                                     8:  byte array
 287  *                                     9:  short array
 288  *                                     10: int array
 289  *                                     11: long array
 290  *                          [u1]*      elements
 291  *
 292  * HPROF_CPU_SAMPLES        a set of sample traces of running threads
 293  *
 294  *                u4        total number of samples
 295  *                u4        # of traces
 296  *               [u4        # of samples
 297  *                u4]*      stack trace serial number
 298  *
 299  * HPROF_CONTROL_SETTINGS   the settings of on/off switches
 300  *
 301  *                u4        0x00000001: alloc traces on/off
 302  *                          0x00000002: cpu sampling on/off
 303  *                u2        stack trace depth
 304  *
 305  *
 306  * When the header is "JAVA PROFILE 1.0.2" a heap dump can optionally
 307  * be generated as a sequence of heap dump segments. This sequence is
 308  * terminated by an end record. The additional tags allowed by format
 309  * "JAVA PROFILE 1.0.2" are:
 310  *
 311  * HPROF_HEAP_DUMP_SEGMENT  denote a heap dump segment
 312  *
 313  *               [heap dump sub-records]*
 314  *               The same sub-record types allowed by HPROF_HEAP_DUMP
 315  *
 316  * HPROF_HEAP_DUMP_END      denotes the end of a heap dump
 317  *
 318  */
 319 
 320 
 321 // HPROF tags
 322 
 323 typedef enum {
 324   // top-level records
 325   HPROF_UTF8                    = 0x01,
 326   HPROF_LOAD_CLASS              = 0x02,
 327   HPROF_UNLOAD_CLASS            = 0x03,
 328   HPROF_FRAME                   = 0x04,
 329   HPROF_TRACE                   = 0x05,
 330   HPROF_ALLOC_SITES             = 0x06,
 331   HPROF_HEAP_SUMMARY            = 0x07,
 332   HPROF_START_THREAD            = 0x0A,
 333   HPROF_END_THREAD              = 0x0B,
 334   HPROF_HEAP_DUMP               = 0x0C,
 335   HPROF_CPU_SAMPLES             = 0x0D,
 336   HPROF_CONTROL_SETTINGS        = 0x0E,
 337 
 338   // 1.0.2 record types
 339   HPROF_HEAP_DUMP_SEGMENT       = 0x1C,
 340   HPROF_HEAP_DUMP_END           = 0x2C,
 341 
 342   // field types
 343   HPROF_ARRAY_OBJECT            = 0x01,
 344   HPROF_NORMAL_OBJECT           = 0x02,
 345   HPROF_BOOLEAN                 = 0x04,
 346   HPROF_CHAR                    = 0x05,
 347   HPROF_FLOAT                   = 0x06,
 348   HPROF_DOUBLE                  = 0x07,
 349   HPROF_BYTE                    = 0x08,
 350   HPROF_SHORT                   = 0x09,
 351   HPROF_INT                     = 0x0A,
 352   HPROF_LONG                    = 0x0B,
 353 
 354   // data-dump sub-records
 355   HPROF_GC_ROOT_UNKNOWN         = 0xFF,
 356   HPROF_GC_ROOT_JNI_GLOBAL      = 0x01,
 357   HPROF_GC_ROOT_JNI_LOCAL       = 0x02,
 358   HPROF_GC_ROOT_JAVA_FRAME      = 0x03,
 359   HPROF_GC_ROOT_NATIVE_STACK    = 0x04,
 360   HPROF_GC_ROOT_STICKY_CLASS    = 0x05,
 361   HPROF_GC_ROOT_THREAD_BLOCK    = 0x06,
 362   HPROF_GC_ROOT_MONITOR_USED    = 0x07,
 363   HPROF_GC_ROOT_THREAD_OBJ      = 0x08,
 364   HPROF_GC_CLASS_DUMP           = 0x20,
 365   HPROF_GC_INSTANCE_DUMP        = 0x21,
 366   HPROF_GC_OBJ_ARRAY_DUMP       = 0x22,
 367   HPROF_GC_PRIM_ARRAY_DUMP      = 0x23
 368 } hprofTag;
 369 
 370 // Default stack trace ID (used for dummy HPROF_TRACE record)
 371 enum {
 372   STACK_TRACE_ID = 1,
 373   INITIAL_CLASS_COUNT = 200
 374 };
 375 
 376 // Supports I/O operations on a dump file
 377 
 378 class DumpWriter : public StackObj {
 379  private:
 380   enum {
 381     io_buffer_size  = 8*M
 382   };
 383 
 384   int _fd;              // file descriptor (-1 if dump file not open)
 385   julong _bytes_written; // number of byte written to dump file
 386 
 387   char* _buffer;    // internal buffer
 388   size_t _size;
 389   size_t _pos;
 390 
 391   jlong _dump_start;
 392 
 393   char* _error;   // error message when I/O fails
 394 
 395   void set_file_descriptor(int fd)              { _fd = fd; }
 396   int file_descriptor() const                   { return _fd; }
 397 
 398   char* buffer() const                          { return _buffer; }
 399   size_t buffer_size() const                    { return _size; }
 400   size_t position() const                       { return _pos; }
 401   void set_position(size_t pos)                 { _pos = pos; }
 402 
 403   void set_error(const char* error)             { _error = (char*)os::strdup(error); }
 404 
 405   // all I/O go through this function
 406   void write_internal(void* s, size_t len);
 407 
 408  public:
 409   DumpWriter(const char* path);
 410   ~DumpWriter();
 411 
 412   void close();
 413   bool is_open() const                  { return file_descriptor() >= 0; }
 414   void flush();
 415 
 416   jlong dump_start() const                      { return _dump_start; }
 417   void set_dump_start(jlong pos);
 418   julong current_record_length();
 419 
 420   // total number of bytes written to the disk
 421   julong bytes_written() const          { return _bytes_written; }
 422 
 423   // adjust the number of bytes written to disk (used to keep the count
 424   // of the number of bytes written in case of rewrites)
 425   void adjust_bytes_written(jlong n)    { _bytes_written += n; }
 426 
 427   // number of (buffered) bytes as yet unwritten to the dump file
 428   size_t bytes_unwritten() const        { return position(); }
 429 
 430   char* error() const                   { return _error; }
 431 
 432   jlong current_offset();
 433   void seek_to_offset(jlong pos);
 434 
 435   // writer functions
 436   void write_raw(void* s, size_t len);
 437   void write_u1(u1 x)                   { write_raw((void*)&x, 1); }
 438   void write_u2(u2 x);
 439   void write_u4(u4 x);
 440   void write_u8(u8 x);
 441   void write_objectID(oop o);
 442   void write_symbolID(Symbol* o);
 443   void write_classID(Klass* k);
 444   void write_id(u4 x);
 445 };
 446 
 447 DumpWriter::DumpWriter(const char* path) {
 448   // try to allocate an I/O buffer of io_buffer_size. If there isn't
 449   // sufficient memory then reduce size until we can allocate something.
 450   _size = io_buffer_size;
 451   do {
 452     _buffer = (char*)os::malloc(_size, mtInternal);
 453     if (_buffer == NULL) {
 454       _size = _size >> 1;
 455     }
 456   } while (_buffer == NULL && _size > 0);
 457   assert((_size > 0 && _buffer != NULL) || (_size == 0 && _buffer == NULL), "sanity check");
 458   _pos = 0;
 459   _error = NULL;
 460   _bytes_written = 0L;
 461   _dump_start = (jlong)-1;
 462   _fd = os::create_binary_file(path, false);    // don't replace existing file
 463 
 464   // if the open failed we record the error
 465   if (_fd < 0) {
 466     _error = (char*)os::strdup(os::strerror(errno));
 467   }
 468 }
 469 
 470 DumpWriter::~DumpWriter() {
 471   // flush and close dump file
 472   if (is_open()) {
 473     close();
 474   }
 475   if (_buffer != NULL) os::free(_buffer);
 476   if (_error != NULL) os::free(_error);
 477 }
 478 
 479 // closes dump file (if open)
 480 void DumpWriter::close() {
 481   // flush and close dump file
 482   if (is_open()) {
 483     flush();
 484     os::close(file_descriptor());
 485     set_file_descriptor(-1);
 486   }
 487 }
 488 
 489 // sets the dump starting position
 490 void DumpWriter::set_dump_start(jlong pos) {
 491   _dump_start = pos;
 492 }
 493 
 494 julong DumpWriter::current_record_length() {
 495   if (is_open()) {
 496     // calculate the size of the dump record
 497     julong dump_end = bytes_written() + bytes_unwritten();
 498     assert(dump_end == (size_t)current_offset(), "checking");
 499     julong dump_len = dump_end - dump_start() - 4;
 500     return dump_len;
 501   }
 502   return 0;
 503 }
 504 
 505 // write directly to the file
 506 void DumpWriter::write_internal(void* s, size_t len) {
 507   if (is_open()) {
 508     const char* pos = (char*)s;
 509     ssize_t n = 0;
 510     while (len > 0) {
 511       uint tmp = (uint)MIN2(len, (size_t)UINT_MAX);
 512       n = os::write(file_descriptor(), pos, tmp);
 513 
 514       if (n < 0) {
 515         // EINTR cannot happen here, os::write will take care of that
 516         set_error(os::strerror(errno));
 517         os::close(file_descriptor());
 518         set_file_descriptor(-1);
 519         return;
 520       }
 521 
 522       _bytes_written += n;
 523       pos += n;
 524       len -= n;
 525     }
 526   }
 527 }
 528 
 529 // write raw bytes
 530 void DumpWriter::write_raw(void* s, size_t len) {
 531   if (is_open()) {
 532     // flush buffer to make room
 533     if ((position() + len) >= buffer_size()) {
 534       flush();
 535     }
 536 
 537     // buffer not available or too big to buffer it
 538     if ((buffer() == NULL) || (len >= buffer_size())) {
 539       write_internal(s, len);
 540     } else {
 541       // Should optimize this for u1/u2/u4/u8 sizes.
 542       memcpy(buffer() + position(), s, len);
 543       set_position(position() + len);
 544     }
 545   }
 546 }
 547 
 548 // flush any buffered bytes to the file
 549 void DumpWriter::flush() {
 550   if (is_open() && position() > 0) {
 551     write_internal(buffer(), position());
 552     set_position(0);
 553   }
 554 }
 555 
 556 jlong DumpWriter::current_offset() {
 557   if (is_open()) {
 558     // the offset is the file offset plus whatever we have buffered
 559     jlong offset = os::current_file_offset(file_descriptor());
 560     assert(offset >= 0, "lseek failed");
 561     return offset + position();
 562   } else {
 563     return (jlong)-1;
 564   }
 565 }
 566 
 567 void DumpWriter::seek_to_offset(jlong off) {
 568   assert(off >= 0, "bad offset");
 569 
 570   // need to flush before seeking
 571   flush();
 572 
 573   // may be closed due to I/O error
 574   if (is_open()) {
 575     jlong n = os::seek_to_file_offset(file_descriptor(), off);
 576     assert(n >= 0, "lseek failed");
 577   }
 578 }
 579 
 580 void DumpWriter::write_u2(u2 x) {
 581   u2 v;
 582   Bytes::put_Java_u2((address)&v, x);
 583   write_raw((void*)&v, 2);
 584 }
 585 
 586 void DumpWriter::write_u4(u4 x) {
 587   u4 v;
 588   Bytes::put_Java_u4((address)&v, x);
 589   write_raw((void*)&v, 4);
 590 }
 591 
 592 void DumpWriter::write_u8(u8 x) {
 593   u8 v;
 594   Bytes::put_Java_u8((address)&v, x);
 595   write_raw((void*)&v, 8);
 596 }
 597 
 598 void DumpWriter::write_objectID(oop o) {
 599   address a = (address)o;
 600 #ifdef _LP64
 601   write_u8((u8)a);
 602 #else
 603   write_u4((u4)a);
 604 #endif
 605 }
 606 
 607 void DumpWriter::write_symbolID(Symbol* s) {
 608   address a = (address)((uintptr_t)s);
 609 #ifdef _LP64
 610   write_u8((u8)a);
 611 #else
 612   write_u4((u4)a);
 613 #endif
 614 }
 615 
 616 void DumpWriter::write_id(u4 x) {
 617 #ifdef _LP64
 618   write_u8((u8) x);
 619 #else
 620   write_u4(x);
 621 #endif
 622 }
 623 
 624 // We use java mirror as the class ID
 625 void DumpWriter::write_classID(Klass* k) {
 626   write_objectID(k->java_mirror());
 627 }
 628 
 629 
 630 
 631 // Support class with a collection of functions used when dumping the heap
 632 
 633 class DumperSupport : AllStatic {
 634  public:
 635 
 636   // write a header of the given type
 637   static void write_header(DumpWriter* writer, hprofTag tag, u4 len);
 638 
 639   // returns hprof tag for the given type signature
 640   static hprofTag sig2tag(Symbol* sig);
 641   // returns hprof tag for the given basic type
 642   static hprofTag type2tag(BasicType type);
 643 
 644   // returns the size of the instance of the given class
 645   static u4 instance_size(Klass* k);
 646 
 647   // dump a jfloat
 648   static void dump_float(DumpWriter* writer, jfloat f);
 649   // dump a jdouble
 650   static void dump_double(DumpWriter* writer, jdouble d);
 651   // dumps the raw value of the given field
 652   static void dump_field_value(DumpWriter* writer, char type, address addr);
 653   // dumps static fields of the given class
 654   static void dump_static_fields(DumpWriter* writer, Klass* k);
 655   // dump the raw values of the instance fields of the given object
 656   static void dump_instance_fields(DumpWriter* writer, oop o);
 657   // dumps the definition of the instance fields for a given class
 658   static void dump_instance_field_descriptors(DumpWriter* writer, Klass* k);
 659   // creates HPROF_GC_INSTANCE_DUMP record for the given object
 660   static void dump_instance(DumpWriter* writer, oop o);
 661   // creates HPROF_GC_CLASS_DUMP record for the given class and each of its
 662   // array classes
 663   static void dump_class_and_array_classes(DumpWriter* writer, Klass* k);
 664   // creates HPROF_GC_CLASS_DUMP record for a given primitive array
 665   // class (and each multi-dimensional array class too)
 666   static void dump_basic_type_array_class(DumpWriter* writer, Klass* k);
 667 
 668   // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
 669   static void dump_object_array(DumpWriter* writer, objArrayOop array);
 670   // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
 671   static void dump_prim_array(DumpWriter* writer, typeArrayOop array);
 672   // create HPROF_FRAME record for the given method and bci
 673   static void dump_stack_frame(DumpWriter* writer, int frame_serial_num, int class_serial_num, Method* m, int bci);
 674 
 675   // check if we need to truncate an array
 676   static int calculate_array_max_length(DumpWriter* writer, arrayOop array, short header_size);
 677 
 678   // writes a HPROF_HEAP_DUMP_SEGMENT record
 679   static void write_dump_header(DumpWriter* writer);
 680 
 681   // fixes up the length of the current dump record
 682   static void write_current_dump_record_length(DumpWriter* writer);
 683 
 684   // fixes up the current dump record and writes HPROF_HEAP_DUMP_END record
 685   static void end_of_dump(DumpWriter* writer);
 686 };
 687 
 688 // write a header of the given type
 689 void DumperSupport:: write_header(DumpWriter* writer, hprofTag tag, u4 len) {
 690   writer->write_u1((u1)tag);
 691   writer->write_u4(0);                  // current ticks
 692   writer->write_u4(len);
 693 }
 694 
 695 // returns hprof tag for the given type signature
 696 hprofTag DumperSupport::sig2tag(Symbol* sig) {
 697   switch (sig->byte_at(0)) {
 698     case JVM_SIGNATURE_CLASS    : return HPROF_NORMAL_OBJECT;
 699     case JVM_SIGNATURE_ARRAY    : return HPROF_NORMAL_OBJECT;
 700     case JVM_SIGNATURE_BYTE     : return HPROF_BYTE;
 701     case JVM_SIGNATURE_CHAR     : return HPROF_CHAR;
 702     case JVM_SIGNATURE_FLOAT    : return HPROF_FLOAT;
 703     case JVM_SIGNATURE_DOUBLE   : return HPROF_DOUBLE;
 704     case JVM_SIGNATURE_INT      : return HPROF_INT;
 705     case JVM_SIGNATURE_LONG     : return HPROF_LONG;
 706     case JVM_SIGNATURE_SHORT    : return HPROF_SHORT;
 707     case JVM_SIGNATURE_BOOLEAN  : return HPROF_BOOLEAN;
 708     default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
 709   }
 710 }
 711 
 712 hprofTag DumperSupport::type2tag(BasicType type) {
 713   switch (type) {
 714     case T_BYTE     : return HPROF_BYTE;
 715     case T_CHAR     : return HPROF_CHAR;
 716     case T_FLOAT    : return HPROF_FLOAT;
 717     case T_DOUBLE   : return HPROF_DOUBLE;
 718     case T_INT      : return HPROF_INT;
 719     case T_LONG     : return HPROF_LONG;
 720     case T_SHORT    : return HPROF_SHORT;
 721     case T_BOOLEAN  : return HPROF_BOOLEAN;
 722     default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
 723   }
 724 }
 725 
 726 // dump a jfloat
 727 void DumperSupport::dump_float(DumpWriter* writer, jfloat f) {
 728   if (g_isnan(f)) {
 729     writer->write_u4(0x7fc00000);    // collapsing NaNs
 730   } else {
 731     union {
 732       int i;
 733       float f;
 734     } u;
 735     u.f = (float)f;
 736     writer->write_u4((u4)u.i);
 737   }
 738 }
 739 
 740 // dump a jdouble
 741 void DumperSupport::dump_double(DumpWriter* writer, jdouble d) {
 742   union {
 743     jlong l;
 744     double d;
 745   } u;
 746   if (g_isnan(d)) {                 // collapsing NaNs
 747     u.l = (jlong)(0x7ff80000);
 748     u.l = (u.l << 32);
 749   } else {
 750     u.d = (double)d;
 751   }
 752   writer->write_u8((u8)u.l);
 753 }
 754 
 755 // dumps the raw value of the given field
 756 void DumperSupport::dump_field_value(DumpWriter* writer, char type, address addr) {
 757   switch (type) {
 758     case JVM_SIGNATURE_CLASS :
 759     case JVM_SIGNATURE_ARRAY : {
 760       oop o;
 761       if (UseCompressedOops) {
 762         o = oopDesc::load_decode_heap_oop((narrowOop*)addr);
 763       } else {
 764         o = oopDesc::load_decode_heap_oop((oop*)addr);
 765       }
 766 
 767       // reflection and Unsafe classes may have a reference to a
 768       // Klass* so filter it out.
 769       assert(oopDesc::is_oop_or_null(o), "Expected an oop or NULL at " PTR_FORMAT, p2i(o));
 770       writer->write_objectID(o);
 771       break;
 772     }
 773     case JVM_SIGNATURE_BYTE     : {
 774       jbyte* b = (jbyte*)addr;
 775       writer->write_u1((u1)*b);
 776       break;
 777     }
 778     case JVM_SIGNATURE_CHAR     : {
 779       jchar* c = (jchar*)addr;
 780       writer->write_u2((u2)*c);
 781       break;
 782     }
 783     case JVM_SIGNATURE_SHORT : {
 784       jshort* s = (jshort*)addr;
 785       writer->write_u2((u2)*s);
 786       break;
 787     }
 788     case JVM_SIGNATURE_FLOAT : {
 789       jfloat* f = (jfloat*)addr;
 790       dump_float(writer, *f);
 791       break;
 792     }
 793     case JVM_SIGNATURE_DOUBLE : {
 794       jdouble* f = (jdouble*)addr;
 795       dump_double(writer, *f);
 796       break;
 797     }
 798     case JVM_SIGNATURE_INT : {
 799       jint* i = (jint*)addr;
 800       writer->write_u4((u4)*i);
 801       break;
 802     }
 803     case JVM_SIGNATURE_LONG     : {
 804       jlong* l = (jlong*)addr;
 805       writer->write_u8((u8)*l);
 806       break;
 807     }
 808     case JVM_SIGNATURE_BOOLEAN : {
 809       jboolean* b = (jboolean*)addr;
 810       writer->write_u1((u1)*b);
 811       break;
 812     }
 813     default : ShouldNotReachHere();
 814   }
 815 }
 816 
 817 // returns the size of the instance of the given class
 818 u4 DumperSupport::instance_size(Klass* k) {
 819   HandleMark hm;
 820   InstanceKlass* ik = InstanceKlass::cast(k);
 821 
 822   u4 size = 0;
 823 
 824   for (FieldStream fld(ik, false, false); !fld.eos(); fld.next()) {
 825     if (!fld.access_flags().is_static()) {
 826       Symbol* sig = fld.signature();
 827       switch (sig->byte_at(0)) {
 828         case JVM_SIGNATURE_CLASS   :
 829         case JVM_SIGNATURE_ARRAY   : size += oopSize; break;
 830 
 831         case JVM_SIGNATURE_BYTE    :
 832         case JVM_SIGNATURE_BOOLEAN : size += 1; break;
 833 
 834         case JVM_SIGNATURE_CHAR    :
 835         case JVM_SIGNATURE_SHORT   : size += 2; break;
 836 
 837         case JVM_SIGNATURE_INT     :
 838         case JVM_SIGNATURE_FLOAT   : size += 4; break;
 839 
 840         case JVM_SIGNATURE_LONG    :
 841         case JVM_SIGNATURE_DOUBLE  : size += 8; break;
 842 
 843         default : ShouldNotReachHere();
 844       }
 845     }
 846   }
 847   return size;
 848 }
 849 
 850 // dumps static fields of the given class
 851 void DumperSupport::dump_static_fields(DumpWriter* writer, Klass* k) {
 852   HandleMark hm;
 853   InstanceKlass* ik = InstanceKlass::cast(k);
 854 
 855   // pass 1 - count the static fields
 856   u2 field_count = 0;
 857   for (FieldStream fldc(ik, true, true); !fldc.eos(); fldc.next()) {
 858     if (fldc.access_flags().is_static()) field_count++;
 859   }
 860 
 861   // Add in resolved_references which is referenced by the cpCache
 862   // The resolved_references is an array per InstanceKlass holding the
 863   // strings and other oops resolved from the constant pool.
 864   oop resolved_references = ik->constants()->resolved_references_or_null();
 865   if (resolved_references != NULL) {
 866     field_count++;
 867 
 868     // Add in the resolved_references of the used previous versions of the class
 869     // in the case of RedefineClasses
 870     InstanceKlass* prev = ik->previous_versions();
 871     while (prev != NULL && prev->constants()->resolved_references_or_null() != NULL) {
 872       field_count++;
 873       prev = prev->previous_versions();
 874     }
 875   }
 876 
 877   // Also provide a pointer to the init_lock if present, so there aren't unreferenced int[0]
 878   // arrays.
 879   oop init_lock = ik->init_lock();
 880   if (init_lock != NULL) {
 881     field_count++;
 882   }
 883 
 884   writer->write_u2(field_count);
 885 
 886   // pass 2 - dump the field descriptors and raw values
 887   for (FieldStream fld(ik, true, true); !fld.eos(); fld.next()) {
 888     if (fld.access_flags().is_static()) {
 889       Symbol* sig = fld.signature();
 890 
 891       writer->write_symbolID(fld.name());   // name
 892       writer->write_u1(sig2tag(sig));       // type
 893 
 894       // value
 895       int offset = fld.offset();
 896       address addr = (address)ik->java_mirror() + offset;
 897 
 898       dump_field_value(writer, sig->byte_at(0), addr);
 899     }
 900   }
 901 
 902   // Add resolved_references for each class that has them
 903   if (resolved_references != NULL) {
 904     writer->write_symbolID(vmSymbols::resolved_references_name());  // name
 905     writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
 906     writer->write_objectID(resolved_references);
 907 
 908     // Also write any previous versions
 909     InstanceKlass* prev = ik->previous_versions();
 910     while (prev != NULL && prev->constants()->resolved_references_or_null() != NULL) {
 911       writer->write_symbolID(vmSymbols::resolved_references_name());  // name
 912       writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
 913       writer->write_objectID(prev->constants()->resolved_references());
 914       prev = prev->previous_versions();
 915     }
 916   }
 917 
 918   // Add init lock to the end if the class is not yet initialized
 919   if (init_lock != NULL) {
 920     writer->write_symbolID(vmSymbols::init_lock_name());         // name
 921     writer->write_u1(sig2tag(vmSymbols::int_array_signature())); // type
 922     writer->write_objectID(init_lock);
 923   }
 924 }
 925 
 926 // dump the raw values of the instance fields of the given object
 927 void DumperSupport::dump_instance_fields(DumpWriter* writer, oop o) {
 928   HandleMark hm;
 929   InstanceKlass* ik = InstanceKlass::cast(o->klass());
 930 
 931   for (FieldStream fld(ik, false, false); !fld.eos(); fld.next()) {
 932     if (!fld.access_flags().is_static()) {
 933       Symbol* sig = fld.signature();
 934       address addr = (address)o + fld.offset();
 935 
 936       dump_field_value(writer, sig->byte_at(0), addr);
 937     }
 938   }
 939 }
 940 
 941 // dumps the definition of the instance fields for a given class
 942 void DumperSupport::dump_instance_field_descriptors(DumpWriter* writer, Klass* k) {
 943   HandleMark hm;
 944   InstanceKlass* ik = InstanceKlass::cast(k);
 945 
 946   // pass 1 - count the instance fields
 947   u2 field_count = 0;
 948   for (FieldStream fldc(ik, true, true); !fldc.eos(); fldc.next()) {
 949     if (!fldc.access_flags().is_static()) field_count++;
 950   }
 951 
 952   writer->write_u2(field_count);
 953 
 954   // pass 2 - dump the field descriptors
 955   for (FieldStream fld(ik, true, true); !fld.eos(); fld.next()) {
 956     if (!fld.access_flags().is_static()) {
 957       Symbol* sig = fld.signature();
 958 
 959       writer->write_symbolID(fld.name());   // name
 960       writer->write_u1(sig2tag(sig));       // type
 961     }
 962   }
 963 }
 964 
 965 // creates HPROF_GC_INSTANCE_DUMP record for the given object
 966 void DumperSupport::dump_instance(DumpWriter* writer, oop o) {
 967   Klass* k = o->klass();
 968 
 969   writer->write_u1(HPROF_GC_INSTANCE_DUMP);
 970   writer->write_objectID(o);
 971   writer->write_u4(STACK_TRACE_ID);
 972 
 973   // class ID
 974   writer->write_classID(k);
 975 
 976   // number of bytes that follow
 977   writer->write_u4(instance_size(k) );
 978 
 979   // field values
 980   dump_instance_fields(writer, o);
 981 }
 982 
 983 // creates HPROF_GC_CLASS_DUMP record for the given class and each of
 984 // its array classes
 985 void DumperSupport::dump_class_and_array_classes(DumpWriter* writer, Klass* k) {
 986   InstanceKlass* ik = InstanceKlass::cast(k);
 987 
 988   // We can safepoint and do a heap dump at a point where we have a Klass,
 989   // but no java mirror class has been setup for it. So we need to check
 990   // that the class is at least loaded, to avoid crash from a null mirror.
 991   if (!ik->is_loaded()) {
 992     return;
 993   }
 994 
 995   writer->write_u1(HPROF_GC_CLASS_DUMP);
 996 
 997   // class ID
 998   writer->write_classID(ik);
 999   writer->write_u4(STACK_TRACE_ID);
1000 
1001   // super class ID
1002   Klass* java_super = ik->java_super();
1003   if (java_super == NULL) {
1004     writer->write_objectID(oop(NULL));
1005   } else {
1006     writer->write_classID(java_super);
1007   }
1008 
1009   writer->write_objectID(ik->class_loader());
1010   writer->write_objectID(ik->signers());
1011   writer->write_objectID(ik->protection_domain());
1012 
1013   // reserved
1014   writer->write_objectID(oop(NULL));
1015   writer->write_objectID(oop(NULL));
1016 
1017   // instance size
1018   writer->write_u4(DumperSupport::instance_size(k));
1019 
1020   // size of constant pool - ignored by HAT 1.1
1021   writer->write_u2(0);
1022 
1023   // number of static fields
1024   dump_static_fields(writer, k);
1025 
1026   // description of instance fields
1027   dump_instance_field_descriptors(writer, k);
1028 
1029   // array classes
1030   k = k->array_klass_or_null();
1031   while (k != NULL) {
1032     Klass* klass = k;
1033     assert(klass->is_objArray_klass(), "not an ObjArrayKlass");
1034 
1035     writer->write_u1(HPROF_GC_CLASS_DUMP);
1036     writer->write_classID(klass);
1037     writer->write_u4(STACK_TRACE_ID);
1038 
1039     // super class of array classes is java.lang.Object
1040     java_super = klass->java_super();
1041     assert(java_super != NULL, "checking");
1042     writer->write_classID(java_super);
1043 
1044     writer->write_objectID(ik->class_loader());
1045     writer->write_objectID(ik->signers());
1046     writer->write_objectID(ik->protection_domain());
1047 
1048     writer->write_objectID(oop(NULL));    // reserved
1049     writer->write_objectID(oop(NULL));
1050     writer->write_u4(0);             // instance size
1051     writer->write_u2(0);             // constant pool
1052     writer->write_u2(0);             // static fields
1053     writer->write_u2(0);             // instance fields
1054 
1055     // get the array class for the next rank
1056     k = klass->array_klass_or_null();
1057   }
1058 }
1059 
1060 // creates HPROF_GC_CLASS_DUMP record for a given primitive array
1061 // class (and each multi-dimensional array class too)
1062 void DumperSupport::dump_basic_type_array_class(DumpWriter* writer, Klass* k) {
1063  // array classes
1064  while (k != NULL) {
1065     Klass* klass = k;
1066 
1067     writer->write_u1(HPROF_GC_CLASS_DUMP);
1068     writer->write_classID(klass);
1069     writer->write_u4(STACK_TRACE_ID);
1070 
1071     // super class of array classes is java.lang.Object
1072     Klass* java_super = klass->java_super();
1073     assert(java_super != NULL, "checking");
1074     writer->write_classID(java_super);
1075 
1076     writer->write_objectID(oop(NULL));    // loader
1077     writer->write_objectID(oop(NULL));    // signers
1078     writer->write_objectID(oop(NULL));    // protection domain
1079 
1080     writer->write_objectID(oop(NULL));    // reserved
1081     writer->write_objectID(oop(NULL));
1082     writer->write_u4(0);             // instance size
1083     writer->write_u2(0);             // constant pool
1084     writer->write_u2(0);             // static fields
1085     writer->write_u2(0);             // instance fields
1086 
1087     // get the array class for the next rank
1088     k = klass->array_klass_or_null();
1089   }
1090 }
1091 
1092 // Hprof uses an u4 as record length field,
1093 // which means we need to truncate arrays that are too long.
1094 int DumperSupport::calculate_array_max_length(DumpWriter* writer, arrayOop array, short header_size) {
1095   BasicType type = ArrayKlass::cast(array->klass())->element_type();
1096   assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type");
1097 
1098   int length = array->length();
1099 
1100   int type_size;
1101   if (type == T_OBJECT) {
1102     type_size = sizeof(address);
1103   } else {
1104     type_size = type2aelembytes(type);
1105   }
1106 
1107   size_t length_in_bytes = (size_t)length * type_size;
1108 
1109   // Create a new record if the current record is non-empty and the array can't fit.
1110   julong current_record_length = writer->current_record_length();
1111   if (current_record_length > 0 &&
1112       (current_record_length + header_size + length_in_bytes) > max_juint) {
1113     write_current_dump_record_length(writer);
1114     write_dump_header(writer);
1115 
1116     // We now have an empty record.
1117     current_record_length = 0;
1118   }
1119 
1120   // Calculate max bytes we can use.
1121   uint max_bytes = max_juint - (header_size + current_record_length);
1122 
1123   // Array too long for the record?
1124   // Calculate max length and return it.
1125   if (length_in_bytes > max_bytes) {
1126     length = max_bytes / type_size;
1127     length_in_bytes = (size_t)length * type_size;
1128 
1129     warning("cannot dump array of type %s[] with length %d; truncating to length %d",
1130             type2name_tab[type], array->length(), length);
1131   }
1132   return length;
1133 }
1134 
1135 // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
1136 void DumperSupport::dump_object_array(DumpWriter* writer, objArrayOop array) {
1137   // sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID) + sizeof(classID)
1138   short header_size = 1 + 2 * 4 + 2 * sizeof(address);
1139 
1140   int length = calculate_array_max_length(writer, array, header_size);
1141 
1142   writer->write_u1(HPROF_GC_OBJ_ARRAY_DUMP);
1143   writer->write_objectID(array);
1144   writer->write_u4(STACK_TRACE_ID);
1145   writer->write_u4(length);
1146 
1147   // array class ID
1148   writer->write_classID(array->klass());
1149 
1150   // [id]* elements
1151   for (int index = 0; index < length; index++) {
1152     oop o = array->obj_at(index);
1153     writer->write_objectID(o);
1154   }
1155 }
1156 
1157 #define WRITE_ARRAY(Array, Type, Size, Length) \
1158   for (int i = 0; i < Length; i++) { writer->write_##Size((Size)Array->Type##_at(i)); }
1159 
1160 // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
1161 void DumperSupport::dump_prim_array(DumpWriter* writer, typeArrayOop array) {
1162   BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
1163 
1164   // 2 * sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID)
1165   short header_size = 2 * 1 + 2 * 4 + sizeof(address);
1166 
1167   int length = calculate_array_max_length(writer, array, header_size);
1168   int type_size = type2aelembytes(type);
1169   u4 length_in_bytes = (u4)length * type_size;
1170 
1171   writer->write_u1(HPROF_GC_PRIM_ARRAY_DUMP);
1172   writer->write_objectID(array);
1173   writer->write_u4(STACK_TRACE_ID);
1174   writer->write_u4(length);
1175   writer->write_u1(type2tag(type));
1176 
1177   // nothing to copy
1178   if (length == 0) {
1179     return;
1180   }
1181 
1182   // If the byte ordering is big endian then we can copy most types directly
1183 
1184   switch (type) {
1185     case T_INT : {
1186       if (Endian::is_Java_byte_ordering_different()) {
1187         WRITE_ARRAY(array, int, u4, length);
1188       } else {
1189         writer->write_raw((void*)(array->int_at_addr(0)), length_in_bytes);
1190       }
1191       break;
1192     }
1193     case T_BYTE : {
1194       writer->write_raw((void*)(array->byte_at_addr(0)), length_in_bytes);
1195       break;
1196     }
1197     case T_CHAR : {
1198       if (Endian::is_Java_byte_ordering_different()) {
1199         WRITE_ARRAY(array, char, u2, length);
1200       } else {
1201         writer->write_raw((void*)(array->char_at_addr(0)), length_in_bytes);
1202       }
1203       break;
1204     }
1205     case T_SHORT : {
1206       if (Endian::is_Java_byte_ordering_different()) {
1207         WRITE_ARRAY(array, short, u2, length);
1208       } else {
1209         writer->write_raw((void*)(array->short_at_addr(0)), length_in_bytes);
1210       }
1211       break;
1212     }
1213     case T_BOOLEAN : {
1214       if (Endian::is_Java_byte_ordering_different()) {
1215         WRITE_ARRAY(array, bool, u1, length);
1216       } else {
1217         writer->write_raw((void*)(array->bool_at_addr(0)), length_in_bytes);
1218       }
1219       break;
1220     }
1221     case T_LONG : {
1222       if (Endian::is_Java_byte_ordering_different()) {
1223         WRITE_ARRAY(array, long, u8, length);
1224       } else {
1225         writer->write_raw((void*)(array->long_at_addr(0)), length_in_bytes);
1226       }
1227       break;
1228     }
1229 
1230     // handle float/doubles in a special value to ensure than NaNs are
1231     // written correctly. TO DO: Check if we can avoid this on processors that
1232     // use IEEE 754.
1233 
1234     case T_FLOAT : {
1235       for (int i = 0; i < length; i++) {
1236         dump_float(writer, array->float_at(i));
1237       }
1238       break;
1239     }
1240     case T_DOUBLE : {
1241       for (int i = 0; i < length; i++) {
1242         dump_double(writer, array->double_at(i));
1243       }
1244       break;
1245     }
1246     default : ShouldNotReachHere();
1247   }
1248 }
1249 
1250 // create a HPROF_FRAME record of the given Method* and bci
1251 void DumperSupport::dump_stack_frame(DumpWriter* writer,
1252                                      int frame_serial_num,
1253                                      int class_serial_num,
1254                                      Method* m,
1255                                      int bci) {
1256   int line_number;
1257   if (m->is_native()) {
1258     line_number = -3;  // native frame
1259   } else {
1260     line_number = m->line_number_from_bci(bci);
1261   }
1262 
1263   write_header(writer, HPROF_FRAME, 4*oopSize + 2*sizeof(u4));
1264   writer->write_id(frame_serial_num);               // frame serial number
1265   writer->write_symbolID(m->name());                // method's name
1266   writer->write_symbolID(m->signature());           // method's signature
1267 
1268   assert(m->method_holder()->is_instance_klass(), "not InstanceKlass");
1269   writer->write_symbolID(m->method_holder()->source_file_name());  // source file name
1270   writer->write_u4(class_serial_num);               // class serial number
1271   writer->write_u4((u4) line_number);               // line number
1272 }
1273 
1274 
1275 // Support class used to generate HPROF_UTF8 records from the entries in the
1276 // SymbolTable.
1277 
1278 class SymbolTableDumper : public SymbolClosure {
1279  private:
1280   DumpWriter* _writer;
1281   DumpWriter* writer() const                { return _writer; }
1282  public:
1283   SymbolTableDumper(DumpWriter* writer)     { _writer = writer; }
1284   void do_symbol(Symbol** p);
1285 };
1286 
1287 void SymbolTableDumper::do_symbol(Symbol** p) {
1288   ResourceMark rm;
1289   Symbol* sym = load_symbol(p);
1290   int len = sym->utf8_length();
1291   if (len > 0) {
1292     char* s = sym->as_utf8();
1293     DumperSupport::write_header(writer(), HPROF_UTF8, oopSize + len);
1294     writer()->write_symbolID(sym);
1295     writer()->write_raw(s, len);
1296   }
1297 }
1298 
1299 // Support class used to generate HPROF_GC_ROOT_JNI_LOCAL records
1300 
1301 class JNILocalsDumper : public OopClosure {
1302  private:
1303   DumpWriter* _writer;
1304   u4 _thread_serial_num;
1305   int _frame_num;
1306   DumpWriter* writer() const                { return _writer; }
1307  public:
1308   JNILocalsDumper(DumpWriter* writer, u4 thread_serial_num) {
1309     _writer = writer;
1310     _thread_serial_num = thread_serial_num;
1311     _frame_num = -1;  // default - empty stack
1312   }
1313   void set_frame_number(int n) { _frame_num = n; }
1314   void do_oop(oop* obj_p);
1315   void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1316 };
1317 
1318 
1319 void JNILocalsDumper::do_oop(oop* obj_p) {
1320   // ignore null or deleted handles
1321   oop o = *obj_p;
1322   if (o != NULL && o != JNIHandles::deleted_handle()) {
1323     writer()->write_u1(HPROF_GC_ROOT_JNI_LOCAL);
1324     writer()->write_objectID(o);
1325     writer()->write_u4(_thread_serial_num);
1326     writer()->write_u4((u4)_frame_num);
1327   }
1328 }
1329 
1330 
1331 // Support class used to generate HPROF_GC_ROOT_JNI_GLOBAL records
1332 
1333 class JNIGlobalsDumper : public OopClosure {
1334  private:
1335   DumpWriter* _writer;
1336   DumpWriter* writer() const                { return _writer; }
1337 
1338  public:
1339   JNIGlobalsDumper(DumpWriter* writer) {
1340     _writer = writer;
1341   }
1342   void do_oop(oop* obj_p);
1343   void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1344 };
1345 
1346 void JNIGlobalsDumper::do_oop(oop* obj_p) {
1347   oop o = *obj_p;
1348 
1349   // ignore these
1350   if (o == NULL || o == JNIHandles::deleted_handle()) return;
1351 
1352   // we ignore global ref to symbols and other internal objects
1353   if (o->is_instance() || o->is_objArray() || o->is_typeArray()) {
1354     writer()->write_u1(HPROF_GC_ROOT_JNI_GLOBAL);
1355     writer()->write_objectID(o);
1356     writer()->write_objectID((oopDesc*)obj_p);      // global ref ID
1357   }
1358 };
1359 
1360 
1361 // Support class used to generate HPROF_GC_ROOT_MONITOR_USED records
1362 
1363 class MonitorUsedDumper : public OopClosure {
1364  private:
1365   DumpWriter* _writer;
1366   DumpWriter* writer() const                { return _writer; }
1367  public:
1368   MonitorUsedDumper(DumpWriter* writer) {
1369     _writer = writer;
1370   }
1371   void do_oop(oop* obj_p) {
1372     writer()->write_u1(HPROF_GC_ROOT_MONITOR_USED);
1373     writer()->write_objectID(*obj_p);
1374   }
1375   void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1376 };
1377 
1378 
1379 // Support class used to generate HPROF_GC_ROOT_STICKY_CLASS records
1380 
1381 class StickyClassDumper : public KlassClosure {
1382  private:
1383   DumpWriter* _writer;
1384   DumpWriter* writer() const                { return _writer; }
1385  public:
1386   StickyClassDumper(DumpWriter* writer) {
1387     _writer = writer;
1388   }
1389   void do_klass(Klass* k) {
1390     if (k->is_instance_klass()) {
1391       InstanceKlass* ik = InstanceKlass::cast(k);
1392         writer()->write_u1(HPROF_GC_ROOT_STICKY_CLASS);
1393         writer()->write_classID(ik);
1394       }
1395     }
1396 };
1397 
1398 
1399 class VM_HeapDumper;
1400 
1401 // Support class using when iterating over the heap.
1402 
1403 class HeapObjectDumper : public ObjectClosure {
1404  private:
1405   VM_HeapDumper* _dumper;
1406   DumpWriter* _writer;
1407 
1408   VM_HeapDumper* dumper()               { return _dumper; }
1409   DumpWriter* writer()                  { return _writer; }
1410 
1411   // used to indicate that a record has been writen
1412   void mark_end_of_record();
1413 
1414  public:
1415   HeapObjectDumper(VM_HeapDumper* dumper, DumpWriter* writer) {
1416     _dumper = dumper;
1417     _writer = writer;
1418   }
1419 
1420   // called for each object in the heap
1421   void do_object(oop o);
1422 };
1423 
1424 void HeapObjectDumper::do_object(oop o) {
1425   // hide the sentinel for deleted handles
1426   if (o == JNIHandles::deleted_handle()) return;
1427 
1428   // skip classes as these emitted as HPROF_GC_CLASS_DUMP records
1429   if (o->klass() == SystemDictionary::Class_klass()) {
1430     if (!java_lang_Class::is_primitive(o)) {
1431       return;
1432     }
1433   }
1434 
1435   if (o->is_instance()) {
1436     // create a HPROF_GC_INSTANCE record for each object
1437     DumperSupport::dump_instance(writer(), o);
1438     mark_end_of_record();
1439   } else if (o->is_objArray()) {
1440     // create a HPROF_GC_OBJ_ARRAY_DUMP record for each object array
1441     DumperSupport::dump_object_array(writer(), objArrayOop(o));
1442     mark_end_of_record();
1443   } else if (o->is_typeArray()) {
1444     // create a HPROF_GC_PRIM_ARRAY_DUMP record for each type array
1445     DumperSupport::dump_prim_array(writer(), typeArrayOop(o));
1446     mark_end_of_record();
1447   }
1448 }
1449 
1450 // The VM operation that performs the heap dump
1451 class VM_HeapDumper : public VM_GC_Operation {
1452  private:
1453   static VM_HeapDumper* _global_dumper;
1454   static DumpWriter*    _global_writer;
1455   DumpWriter*           _local_writer;
1456   JavaThread*           _oome_thread;
1457   Method*               _oome_constructor;
1458   bool _gc_before_heap_dump;
1459   GrowableArray<Klass*>* _klass_map;
1460   ThreadStackTrace** _stack_traces;
1461   int _num_threads;
1462 
1463   // accessors and setters
1464   static VM_HeapDumper* dumper()         {  assert(_global_dumper != NULL, "Error"); return _global_dumper; }
1465   static DumpWriter* writer()            {  assert(_global_writer != NULL, "Error"); return _global_writer; }
1466   void set_global_dumper() {
1467     assert(_global_dumper == NULL, "Error");
1468     _global_dumper = this;
1469   }
1470   void set_global_writer() {
1471     assert(_global_writer == NULL, "Error");
1472     _global_writer = _local_writer;
1473   }
1474   void clear_global_dumper() { _global_dumper = NULL; }
1475   void clear_global_writer() { _global_writer = NULL; }
1476 
1477   bool skip_operation() const;
1478 
1479   // writes a HPROF_LOAD_CLASS record
1480   static void do_load_class(Klass* k);
1481 
1482   // writes a HPROF_GC_CLASS_DUMP record for the given class
1483   // (and each array class too)
1484   static void do_class_dump(Klass* k);
1485 
1486   // writes a HPROF_GC_CLASS_DUMP records for a given basic type
1487   // array (and each multi-dimensional array too)
1488   static void do_basic_type_array_class_dump(Klass* k);
1489 
1490   // HPROF_GC_ROOT_THREAD_OBJ records
1491   int do_thread(JavaThread* thread, u4 thread_serial_num);
1492   void do_threads();
1493 
1494   void add_class_serial_number(Klass* k, int serial_num) {
1495     _klass_map->at_put_grow(serial_num, k);
1496   }
1497 
1498   // HPROF_TRACE and HPROF_FRAME records
1499   void dump_stack_traces();
1500 
1501  public:
1502   VM_HeapDumper(DumpWriter* writer, bool gc_before_heap_dump, bool oome) :
1503     VM_GC_Operation(0 /* total collections,      dummy, ignored */,
1504                     GCCause::_heap_dump /* GC Cause */,
1505                     0 /* total full collections, dummy, ignored */,
1506                     gc_before_heap_dump) {
1507     _local_writer = writer;
1508     _gc_before_heap_dump = gc_before_heap_dump;
1509     _klass_map = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<Klass*>(INITIAL_CLASS_COUNT, true);
1510     _stack_traces = NULL;
1511     _num_threads = 0;
1512     if (oome) {
1513       assert(!Thread::current()->is_VM_thread(), "Dump from OutOfMemoryError cannot be called by the VMThread");
1514       // get OutOfMemoryError zero-parameter constructor
1515       InstanceKlass* oome_ik = SystemDictionary::OutOfMemoryError_klass();
1516       _oome_constructor = oome_ik->find_method(vmSymbols::object_initializer_name(),
1517                                                           vmSymbols::void_method_signature());
1518       // get thread throwing OOME when generating the heap dump at OOME
1519       _oome_thread = JavaThread::current();
1520     } else {
1521       _oome_thread = NULL;
1522       _oome_constructor = NULL;
1523     }
1524   }
1525   ~VM_HeapDumper() {
1526     if (_stack_traces != NULL) {
1527       for (int i=0; i < _num_threads; i++) {
1528         delete _stack_traces[i];
1529       }
1530       FREE_C_HEAP_ARRAY(ThreadStackTrace*, _stack_traces);
1531     }
1532     delete _klass_map;
1533   }
1534 
1535   VMOp_Type type() const { return VMOp_HeapDumper; }
1536   // used to mark sub-record boundary
1537   void check_segment_length();
1538   void doit();
1539 };
1540 
1541 VM_HeapDumper* VM_HeapDumper::_global_dumper = NULL;
1542 DumpWriter*    VM_HeapDumper::_global_writer = NULL;
1543 
1544 bool VM_HeapDumper::skip_operation() const {
1545   return false;
1546 }
1547 
1548  // writes a HPROF_HEAP_DUMP_SEGMENT record
1549 void DumperSupport::write_dump_header(DumpWriter* writer) {
1550   if (writer->is_open()) {
1551     writer->write_u1(HPROF_HEAP_DUMP_SEGMENT);
1552     writer->write_u4(0); // current ticks
1553 
1554     // record the starting position for the dump (its length will be fixed up later)
1555     writer->set_dump_start(writer->current_offset());
1556     writer->write_u4(0);
1557   }
1558 }
1559 
1560 // fixes up the length of the current dump record
1561 void DumperSupport::write_current_dump_record_length(DumpWriter* writer) {
1562   if (writer->is_open()) {
1563     julong dump_end = writer->bytes_written() + writer->bytes_unwritten();
1564     julong dump_len = writer->current_record_length();
1565 
1566     // record length must fit in a u4
1567     if (dump_len > max_juint) {
1568       warning("record is too large");
1569     }
1570 
1571     // seek to the dump start and fix-up the length
1572     assert(writer->dump_start() >= 0, "no dump start recorded");
1573     writer->seek_to_offset(writer->dump_start());
1574     writer->write_u4((u4)dump_len);
1575 
1576     // adjust the total size written to keep the bytes written correct.
1577     writer->adjust_bytes_written(-((jlong) sizeof(u4)));
1578 
1579     // seek to dump end so we can continue
1580     writer->seek_to_offset(dump_end);
1581 
1582     // no current dump record
1583     writer->set_dump_start((jlong)-1);
1584   }
1585 }
1586 
1587 // used on a sub-record boundary to check if we need to start a
1588 // new segment.
1589 void VM_HeapDumper::check_segment_length() {
1590   if (writer()->is_open()) {
1591     julong dump_len = writer()->current_record_length();
1592 
1593     if (dump_len > 2UL*G) {
1594       DumperSupport::write_current_dump_record_length(writer());
1595       DumperSupport::write_dump_header(writer());
1596     }
1597   }
1598 }
1599 
1600 // fixes up the current dump record and writes HPROF_HEAP_DUMP_END record
1601 void DumperSupport::end_of_dump(DumpWriter* writer) {
1602   if (writer->is_open()) {
1603     write_current_dump_record_length(writer);
1604 
1605     writer->write_u1(HPROF_HEAP_DUMP_END);
1606     writer->write_u4(0);
1607     writer->write_u4(0);
1608   }
1609 }
1610 
1611 // marks sub-record boundary
1612 void HeapObjectDumper::mark_end_of_record() {
1613   dumper()->check_segment_length();
1614 }
1615 
1616 // writes a HPROF_LOAD_CLASS record for the class (and each of its
1617 // array classes)
1618 void VM_HeapDumper::do_load_class(Klass* k) {
1619   static u4 class_serial_num = 0;
1620 
1621   // len of HPROF_LOAD_CLASS record
1622   u4 remaining = 2*oopSize + 2*sizeof(u4);
1623 
1624   // write a HPROF_LOAD_CLASS for the class and each array class
1625   do {
1626     DumperSupport::write_header(writer(), HPROF_LOAD_CLASS, remaining);
1627 
1628     // class serial number is just a number
1629     writer()->write_u4(++class_serial_num);
1630 
1631     // class ID
1632     Klass* klass = k;
1633     writer()->write_classID(klass);
1634 
1635     // add the Klass* and class serial number pair
1636     dumper()->add_class_serial_number(klass, class_serial_num);
1637 
1638     writer()->write_u4(STACK_TRACE_ID);
1639 
1640     // class name ID
1641     Symbol* name = klass->name();
1642     writer()->write_symbolID(name);
1643 
1644     // write a LOAD_CLASS record for the array type (if it exists)
1645     k = klass->array_klass_or_null();
1646   } while (k != NULL);
1647 }
1648 
1649 // writes a HPROF_GC_CLASS_DUMP record for the given class
1650 void VM_HeapDumper::do_class_dump(Klass* k) {
1651   if (k->is_instance_klass()) {
1652     DumperSupport::dump_class_and_array_classes(writer(), k);
1653   }
1654 }
1655 
1656 // writes a HPROF_GC_CLASS_DUMP records for a given basic type
1657 // array (and each multi-dimensional array too)
1658 void VM_HeapDumper::do_basic_type_array_class_dump(Klass* k) {
1659   DumperSupport::dump_basic_type_array_class(writer(), k);
1660 }
1661 
1662 // Walk the stack of the given thread.
1663 // Dumps a HPROF_GC_ROOT_JAVA_FRAME record for each local
1664 // Dumps a HPROF_GC_ROOT_JNI_LOCAL record for each JNI local
1665 //
1666 // It returns the number of Java frames in this thread stack
1667 int VM_HeapDumper::do_thread(JavaThread* java_thread, u4 thread_serial_num) {
1668   JNILocalsDumper blk(writer(), thread_serial_num);
1669 
1670   oop threadObj = java_thread->threadObj();
1671   assert(threadObj != NULL, "sanity check");
1672 
1673   int stack_depth = 0;
1674   if (java_thread->has_last_Java_frame()) {
1675 
1676     // vframes are resource allocated
1677     Thread* current_thread = Thread::current();
1678     ResourceMark rm(current_thread);
1679     HandleMark hm(current_thread);
1680 
1681     RegisterMap reg_map(java_thread);
1682     frame f = java_thread->last_frame();
1683     vframe* vf = vframe::new_vframe(&f, &reg_map, java_thread);
1684     frame* last_entry_frame = NULL;
1685     int extra_frames = 0;
1686 
1687     if (java_thread == _oome_thread && _oome_constructor != NULL) {
1688       extra_frames++;
1689     }
1690     while (vf != NULL) {
1691       blk.set_frame_number(stack_depth);
1692       if (vf->is_java_frame()) {
1693 
1694         // java frame (interpreted, compiled, ...)
1695         javaVFrame *jvf = javaVFrame::cast(vf);
1696         if (!(jvf->method()->is_native())) {
1697           StackValueCollection* locals = jvf->locals();
1698           for (int slot=0; slot<locals->size(); slot++) {
1699             if (locals->at(slot)->type() == T_OBJECT) {
1700               oop o = locals->obj_at(slot)();
1701 
1702               if (o != NULL) {
1703                 writer()->write_u1(HPROF_GC_ROOT_JAVA_FRAME);
1704                 writer()->write_objectID(o);
1705                 writer()->write_u4(thread_serial_num);
1706                 writer()->write_u4((u4) (stack_depth + extra_frames));
1707               }
1708             }
1709           }
1710           StackValueCollection *exprs = jvf->expressions();
1711           for(int index = 0; index < exprs->size(); index++) {
1712             if (exprs->at(index)->type() == T_OBJECT) {
1713                oop o = exprs->obj_at(index)();
1714                if (o != NULL) {
1715                  writer()->write_u1(HPROF_GC_ROOT_JAVA_FRAME);
1716                  writer()->write_objectID(o);
1717                  writer()->write_u4(thread_serial_num);
1718                  writer()->write_u4((u4) (stack_depth + extra_frames));
1719                }
1720              }
1721           }
1722         } else {
1723           // native frame
1724           if (stack_depth == 0) {
1725             // JNI locals for the top frame.
1726             java_thread->active_handles()->oops_do(&blk);
1727           } else {
1728             if (last_entry_frame != NULL) {
1729               // JNI locals for the entry frame
1730               assert(last_entry_frame->is_entry_frame(), "checking");
1731               last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(&blk);
1732             }
1733           }
1734         }
1735         // increment only for Java frames
1736         stack_depth++;
1737         last_entry_frame = NULL;
1738 
1739       } else {
1740         // externalVFrame - if it's an entry frame then report any JNI locals
1741         // as roots when we find the corresponding native javaVFrame
1742         frame* fr = vf->frame_pointer();
1743         assert(fr != NULL, "sanity check");
1744         if (fr->is_entry_frame()) {
1745           last_entry_frame = fr;
1746         }
1747       }
1748       vf = vf->sender();
1749     }
1750   } else {
1751     // no last java frame but there may be JNI locals
1752     java_thread->active_handles()->oops_do(&blk);
1753   }
1754   return stack_depth;
1755 }
1756 
1757 
1758 // write a HPROF_GC_ROOT_THREAD_OBJ record for each java thread. Then walk
1759 // the stack so that locals and JNI locals are dumped.
1760 void VM_HeapDumper::do_threads() {
1761   for (int i=0; i < _num_threads; i++) {
1762     JavaThread* thread = _stack_traces[i]->thread();
1763     oop threadObj = thread->threadObj();
1764     u4 thread_serial_num = i+1;
1765     u4 stack_serial_num = thread_serial_num + STACK_TRACE_ID;
1766     writer()->write_u1(HPROF_GC_ROOT_THREAD_OBJ);
1767     writer()->write_objectID(threadObj);
1768     writer()->write_u4(thread_serial_num);  // thread number
1769     writer()->write_u4(stack_serial_num);   // stack trace serial number
1770     int num_frames = do_thread(thread, thread_serial_num);
1771     assert(num_frames == _stack_traces[i]->get_stack_depth(),
1772            "total number of Java frames not matched");
1773   }
1774 }
1775 
1776 
1777 // The VM operation that dumps the heap. The dump consists of the following
1778 // records:
1779 //
1780 //  HPROF_HEADER
1781 //  [HPROF_UTF8]*
1782 //  [HPROF_LOAD_CLASS]*
1783 //  [[HPROF_FRAME]*|HPROF_TRACE]*
1784 //  [HPROF_GC_CLASS_DUMP]*
1785 //  [HPROF_HEAP_DUMP_SEGMENT]*
1786 //  HPROF_HEAP_DUMP_END
1787 //
1788 // The HPROF_TRACE records represent the stack traces where the heap dump
1789 // is generated and a "dummy trace" record which does not include
1790 // any frames. The dummy trace record is used to be referenced as the
1791 // unknown object alloc site.
1792 //
1793 // Each HPROF_HEAP_DUMP_SEGMENT record has a length followed by sub-records.
1794 // To allow the heap dump be generated in a single pass we remember the position
1795 // of the dump length and fix it up after all sub-records have been written.
1796 // To generate the sub-records we iterate over the heap, writing
1797 // HPROF_GC_INSTANCE_DUMP, HPROF_GC_OBJ_ARRAY_DUMP, and HPROF_GC_PRIM_ARRAY_DUMP
1798 // records as we go. Once that is done we write records for some of the GC
1799 // roots.
1800 
1801 void VM_HeapDumper::doit() {
1802 
1803   HandleMark hm;
1804   CollectedHeap* ch = Universe::heap();
1805 
1806   ch->ensure_parsability(false); // must happen, even if collection does
1807                                  // not happen (e.g. due to GCLocker)
1808 
1809   if (_gc_before_heap_dump) {
1810     if (GCLocker::is_active()) {
1811       warning("GC locker is held; pre-heapdump GC was skipped");
1812     } else {
1813       ch->collect_as_vm_thread(GCCause::_heap_dump);
1814     }
1815   }
1816 
1817   // At this point we should be the only dumper active, so
1818   // the following should be safe.
1819   set_global_dumper();
1820   set_global_writer();
1821 
1822   // Write the file header - we always use 1.0.2
1823   size_t used = ch->used();
1824   const char* header = "JAVA PROFILE 1.0.2";
1825 
1826   // header is few bytes long - no chance to overflow int
1827   writer()->write_raw((void*)header, (int)strlen(header));
1828   writer()->write_u1(0); // terminator
1829   writer()->write_u4(oopSize);
1830   writer()->write_u8(os::javaTimeMillis());
1831 
1832   // HPROF_UTF8 records
1833   SymbolTableDumper sym_dumper(writer());
1834   SymbolTable::symbols_do(&sym_dumper);
1835 
1836   // write HPROF_LOAD_CLASS records
1837   ClassLoaderDataGraph::classes_do(&do_load_class);
1838   Universe::basic_type_classes_do(&do_load_class);
1839 
1840   // write HPROF_FRAME and HPROF_TRACE records
1841   // this must be called after _klass_map is built when iterating the classes above.
1842   dump_stack_traces();
1843 
1844   // write HPROF_HEAP_DUMP_SEGMENT
1845   DumperSupport::write_dump_header(writer());
1846 
1847   // Writes HPROF_GC_CLASS_DUMP records
1848   ClassLoaderDataGraph::classes_do(&do_class_dump);
1849   Universe::basic_type_classes_do(&do_basic_type_array_class_dump);
1850   check_segment_length();
1851 
1852   // writes HPROF_GC_INSTANCE_DUMP records.
1853   // After each sub-record is written check_segment_length will be invoked
1854   // to check if the current segment exceeds a threshold. If so, a new
1855   // segment is started.
1856   // The HPROF_GC_CLASS_DUMP and HPROF_GC_INSTANCE_DUMP are the vast bulk
1857   // of the heap dump.
1858   HeapObjectDumper obj_dumper(this, writer());
1859   Universe::heap()->safe_object_iterate(&obj_dumper);
1860 
1861   // HPROF_GC_ROOT_THREAD_OBJ + frames + jni locals
1862   do_threads();
1863   check_segment_length();
1864 
1865   // HPROF_GC_ROOT_MONITOR_USED
1866   MonitorUsedDumper mon_dumper(writer());
1867   ObjectSynchronizer::oops_do(&mon_dumper);
1868   check_segment_length();
1869 
1870   // HPROF_GC_ROOT_JNI_GLOBAL
1871   JNIGlobalsDumper jni_dumper(writer());
1872   JNIHandles::oops_do(&jni_dumper);
1873   Universe::oops_do(&jni_dumper);  // technically not jni roots, but global roots
1874                                    // for things like preallocated throwable backtraces
1875   check_segment_length();
1876 
1877   // HPROF_GC_ROOT_STICKY_CLASS
1878   // These should be classes in the NULL class loader data, and not all classes
1879   // if !ClassUnloading
1880   StickyClassDumper class_dumper(writer());
1881   ClassLoaderData::the_null_class_loader_data()->classes_do(&class_dumper);
1882 
1883   // fixes up the length of the dump record and writes the HPROF_HEAP_DUMP_END record.
1884   DumperSupport::end_of_dump(writer());
1885 
1886   // Now we clear the global variables, so that a future dumper might run.
1887   clear_global_dumper();
1888   clear_global_writer();
1889 }
1890 
1891 void VM_HeapDumper::dump_stack_traces() {
1892   // write a HPROF_TRACE record without any frames to be referenced as object alloc sites
1893   DumperSupport::write_header(writer(), HPROF_TRACE, 3*sizeof(u4));
1894   writer()->write_u4((u4) STACK_TRACE_ID);
1895   writer()->write_u4(0);                    // thread number
1896   writer()->write_u4(0);                    // frame count
1897 
1898   _stack_traces = NEW_C_HEAP_ARRAY(ThreadStackTrace*, Threads::number_of_threads(), mtInternal);
1899   int frame_serial_num = 0;
1900   for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
1901     oop threadObj = thread->threadObj();
1902     if (threadObj != NULL && !thread->is_exiting() && !thread->is_hidden_from_external_view()) {
1903       // dump thread stack trace
1904       ThreadStackTrace* stack_trace = new ThreadStackTrace(thread, false);
1905       stack_trace->dump_stack_at_safepoint(-1);
1906       _stack_traces[_num_threads++] = stack_trace;
1907 
1908       // write HPROF_FRAME records for this thread's stack trace
1909       int depth = stack_trace->get_stack_depth();
1910       int thread_frame_start = frame_serial_num;
1911       int extra_frames = 0;
1912       // write fake frame that makes it look like the thread, which caused OOME,
1913       // is in the OutOfMemoryError zero-parameter constructor
1914       if (thread == _oome_thread && _oome_constructor != NULL) {
1915         int oome_serial_num = _klass_map->find(_oome_constructor->method_holder());
1916         // the class serial number starts from 1
1917         assert(oome_serial_num > 0, "OutOfMemoryError class not found");
1918         DumperSupport::dump_stack_frame(writer(), ++frame_serial_num, oome_serial_num,
1919                                         _oome_constructor, 0);
1920         extra_frames++;
1921       }
1922       for (int j=0; j < depth; j++) {
1923         StackFrameInfo* frame = stack_trace->stack_frame_at(j);
1924         Method* m = frame->method();
1925         int class_serial_num = _klass_map->find(m->method_holder());
1926         // the class serial number starts from 1
1927         assert(class_serial_num > 0, "class not found");
1928         DumperSupport::dump_stack_frame(writer(), ++frame_serial_num, class_serial_num, m, frame->bci());
1929       }
1930       depth += extra_frames;
1931 
1932       // write HPROF_TRACE record for one thread
1933       DumperSupport::write_header(writer(), HPROF_TRACE, 3*sizeof(u4) + depth*oopSize);
1934       int stack_serial_num = _num_threads + STACK_TRACE_ID;
1935       writer()->write_u4(stack_serial_num);      // stack trace serial number
1936       writer()->write_u4((u4) _num_threads);     // thread serial number
1937       writer()->write_u4(depth);                 // frame count
1938       for (int j=1; j <= depth; j++) {
1939         writer()->write_id(thread_frame_start + j);
1940       }
1941     }
1942   }
1943 }
1944 
1945 // dump the heap to given path.
1946 int HeapDumper::dump(const char* path) {
1947   assert(path != NULL && strlen(path) > 0, "path missing");
1948 
1949   // print message in interactive case
1950   if (print_to_tty()) {
1951     tty->print_cr("Dumping heap to %s ...", path);
1952     timer()->start();
1953   }
1954 
1955   // create the dump writer. If the file can be opened then bail
1956   DumpWriter writer(path);
1957   if (!writer.is_open()) {
1958     set_error(writer.error());
1959     if (print_to_tty()) {
1960       tty->print_cr("Unable to create %s: %s", path,
1961         (error() != NULL) ? error() : "reason unknown");
1962     }
1963     return -1;
1964   }
1965 
1966   // generate the dump
1967   VM_HeapDumper dumper(&writer, _gc_before_heap_dump, _oome);
1968   if (Thread::current()->is_VM_thread()) {
1969     assert(SafepointSynchronize::is_at_safepoint(), "Expected to be called at a safepoint");
1970     dumper.doit();
1971   } else {
1972     VMThread::execute(&dumper);
1973   }
1974 
1975   // close dump file and record any error that the writer may have encountered
1976   writer.close();
1977   set_error(writer.error());
1978 
1979   // print message in interactive case
1980   if (print_to_tty()) {
1981     timer()->stop();
1982     if (error() == NULL) {
1983       tty->print_cr("Heap dump file created [" JULONG_FORMAT " bytes in %3.3f secs]",
1984                     writer.bytes_written(), timer()->seconds());
1985     } else {
1986       tty->print_cr("Dump file is incomplete: %s", writer.error());
1987     }
1988   }
1989 
1990   return (writer.error() == NULL) ? 0 : -1;
1991 }
1992 
1993 // stop timer (if still active), and free any error string we might be holding
1994 HeapDumper::~HeapDumper() {
1995   if (timer()->is_active()) {
1996     timer()->stop();
1997   }
1998   set_error(NULL);
1999 }
2000 
2001 
2002 // returns the error string (resource allocated), or NULL
2003 char* HeapDumper::error_as_C_string() const {
2004   if (error() != NULL) {
2005     char* str = NEW_RESOURCE_ARRAY(char, strlen(error())+1);
2006     strcpy(str, error());
2007     return str;
2008   } else {
2009     return NULL;
2010   }
2011 }
2012 
2013 // set the error string
2014 void HeapDumper::set_error(char* error) {
2015   if (_error != NULL) {
2016     os::free(_error);
2017   }
2018   if (error == NULL) {
2019     _error = NULL;
2020   } else {
2021     _error = os::strdup(error);
2022     assert(_error != NULL, "allocation failure");
2023   }
2024 }
2025 
2026 // Called by out-of-memory error reporting by a single Java thread
2027 // outside of a JVM safepoint
2028 void HeapDumper::dump_heap_from_oome() {
2029   HeapDumper::dump_heap(true);
2030 }
2031 
2032 // Called by error reporting by a single Java thread outside of a JVM safepoint,
2033 // or by heap dumping by the VM thread during a (GC) safepoint. Thus, these various
2034 // callers are strictly serialized and guaranteed not to interfere below. For more
2035 // general use, however, this method will need modification to prevent
2036 // inteference when updating the static variables base_path and dump_file_seq below.
2037 void HeapDumper::dump_heap() {
2038   HeapDumper::dump_heap(false);
2039 }
2040 
2041 void HeapDumper::dump_heap(bool oome) {
2042   static char base_path[JVM_MAXPATHLEN] = {'\0'};
2043   static uint dump_file_seq = 0;
2044   char* my_path;
2045   const int max_digit_chars = 20;
2046 
2047   const char* dump_file_name = "java_pid";
2048   const char* dump_file_ext  = ".hprof";
2049 
2050   // The dump file defaults to java_pid<pid>.hprof in the current working
2051   // directory. HeapDumpPath=<file> can be used to specify an alternative
2052   // dump file name or a directory where dump file is created.
2053   if (dump_file_seq == 0) { // first time in, we initialize base_path
2054     // Calculate potentially longest base path and check if we have enough
2055     // allocated statically.
2056     const size_t total_length =
2057                       (HeapDumpPath == NULL ? 0 : strlen(HeapDumpPath)) +
2058                       strlen(os::file_separator()) + max_digit_chars +
2059                       strlen(dump_file_name) + strlen(dump_file_ext) + 1;
2060     if (total_length > sizeof(base_path)) {
2061       warning("Cannot create heap dump file.  HeapDumpPath is too long.");
2062       return;
2063     }
2064 
2065     bool use_default_filename = true;
2066     if (HeapDumpPath == NULL || HeapDumpPath[0] == '\0') {
2067       // HeapDumpPath=<file> not specified
2068     } else {
2069       strcpy(base_path, HeapDumpPath);
2070       // check if the path is a directory (must exist)
2071       DIR* dir = os::opendir(base_path);
2072       if (dir == NULL) {
2073         use_default_filename = false;
2074       } else {
2075         // HeapDumpPath specified a directory. We append a file separator
2076         // (if needed).
2077         os::closedir(dir);
2078         size_t fs_len = strlen(os::file_separator());
2079         if (strlen(base_path) >= fs_len) {
2080           char* end = base_path;
2081           end += (strlen(base_path) - fs_len);
2082           if (strcmp(end, os::file_separator()) != 0) {
2083             strcat(base_path, os::file_separator());
2084           }
2085         }
2086       }
2087     }
2088     // If HeapDumpPath wasn't a file name then we append the default name
2089     if (use_default_filename) {
2090       const size_t dlen = strlen(base_path);  // if heap dump dir specified
2091       jio_snprintf(&base_path[dlen], sizeof(base_path)-dlen, "%s%d%s",
2092                    dump_file_name, os::current_process_id(), dump_file_ext);
2093     }
2094     const size_t len = strlen(base_path) + 1;
2095     my_path = (char*)os::malloc(len, mtInternal);
2096     if (my_path == NULL) {
2097       warning("Cannot create heap dump file.  Out of system memory.");
2098       return;
2099     }
2100     strncpy(my_path, base_path, len);
2101   } else {
2102     // Append a sequence number id for dumps following the first
2103     const size_t len = strlen(base_path) + max_digit_chars + 2; // for '.' and \0
2104     my_path = (char*)os::malloc(len, mtInternal);
2105     if (my_path == NULL) {
2106       warning("Cannot create heap dump file.  Out of system memory.");
2107       return;
2108     }
2109     jio_snprintf(my_path, len, "%s.%d", base_path, dump_file_seq);
2110   }
2111   dump_file_seq++;   // increment seq number for next time we dump
2112 
2113   HeapDumper dumper(false /* no GC before heap dump */,
2114                     true  /* send to tty */,
2115                     oome  /* pass along out-of-memory-error flag */);
2116   dumper.dump(my_path);
2117   os::free(my_path);
2118 }