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