1 /*
   2  * Copyright (c) 2005, 2010, 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 "incls/_precompiled.incl"
  26 # include "incls/_heapDumper.cpp.incl"
  27 
  28 /*
  29  * HPROF binary format - description copied from:
  30  *   src/share/demo/jvmti/hprof/hprof_io.c
  31  *
  32  *
  33  *  header    "JAVA PROFILE 1.0.1" or "JAVA PROFILE 1.0.2"
  34  *            (0-terminated)
  35  *
  36  *  u4        size of identifiers. Identifiers are used to represent
  37  *            UTF8 strings, objects, stack traces, etc. They usually
  38  *            have the same size as host pointers. For example, on
  39  *            Solaris and Win32, the size is 4.
  40  * u4         high word
  41  * u4         low word    number of milliseconds since 0:00 GMT, 1/1/70
  42  * [record]*  a sequence of records.
  43  *
  44  *
  45  * Record format:
  46  *
  47  * u1         a TAG denoting the type of the record
  48  * u4         number of *microseconds* since the time stamp in the
  49  *            header. (wraps around in a little more than an hour)
  50  * u4         number of bytes *remaining* in the record. Note that
  51  *            this number excludes the tag and the length field itself.
  52  * [u1]*      BODY of the record (a sequence of bytes)
  53  *
  54  *
  55  * The following TAGs are supported:
  56  *
  57  * TAG           BODY       notes
  58  *----------------------------------------------------------
  59  * HPROF_UTF8               a UTF8-encoded name
  60  *
  61  *               id         name ID
  62  *               [u1]*      UTF8 characters (no trailing zero)
  63  *
  64  * HPROF_LOAD_CLASS         a newly loaded class
  65  *
  66  *                u4        class serial number (> 0)
  67  *                id        class object ID
  68  *                u4        stack trace serial number
  69  *                id        class name ID
  70  *
  71  * HPROF_UNLOAD_CLASS       an unloading class
  72  *
  73  *                u4        class serial_number
  74  *
  75  * HPROF_FRAME              a Java stack frame
  76  *
  77  *                id        stack frame ID
  78  *                id        method name ID
  79  *                id        method signature ID
  80  *                id        source file name ID
  81  *                u4        class serial number
  82  *                i4        line number. >0: normal
  83  *                                       -1: unknown
  84  *                                       -2: compiled method
  85  *                                       -3: native method
  86  *
  87  * HPROF_TRACE              a Java stack trace
  88  *
  89  *               u4         stack trace serial number
  90  *               u4         thread serial number
  91  *               u4         number of frames
  92  *               [id]*      stack frame IDs
  93  *
  94  *
  95  * HPROF_ALLOC_SITES        a set of heap allocation sites, obtained after GC
  96  *
  97  *               u2         flags 0x0001: incremental vs. complete
  98  *                                0x0002: sorted by allocation vs. live
  99  *                                0x0004: whether to force a GC
 100  *               u4         cutoff ratio
 101  *               u4         total live bytes
 102  *               u4         total live instances
 103  *               u8         total bytes allocated
 104  *               u8         total instances allocated
 105  *               u4         number of sites that follow
 106  *               [u1        is_array: 0:  normal object
 107  *                                    2:  object array
 108  *                                    4:  boolean array
 109  *                                    5:  char array
 110  *                                    6:  float array
 111  *                                    7:  double array
 112  *                                    8:  byte array
 113  *                                    9:  short array
 114  *                                    10: int array
 115  *                                    11: long array
 116  *                u4        class serial number (may be zero during startup)
 117  *                u4        stack trace serial number
 118  *                u4        number of bytes alive
 119  *                u4        number of instances alive
 120  *                u4        number of bytes allocated
 121  *                u4]*      number of instance allocated
 122  *
 123  * HPROF_START_THREAD       a newly started thread.
 124  *
 125  *               u4         thread serial number (> 0)
 126  *               id         thread object ID
 127  *               u4         stack trace serial number
 128  *               id         thread name ID
 129  *               id         thread group name ID
 130  *               id         thread group parent name ID
 131  *
 132  * HPROF_END_THREAD         a terminating thread.
 133  *
 134  *               u4         thread serial number
 135  *
 136  * HPROF_HEAP_SUMMARY       heap summary
 137  *
 138  *               u4         total live bytes
 139  *               u4         total live instances
 140  *               u8         total bytes allocated
 141  *               u8         total instances allocated
 142  *
 143  * HPROF_HEAP_DUMP          denote a heap dump
 144  *
 145  *               [heap dump sub-records]*
 146  *
 147  *                          There are four kinds of heap dump sub-records:
 148  *
 149  *               u1         sub-record type
 150  *
 151  *               HPROF_GC_ROOT_UNKNOWN         unknown root
 152  *
 153  *                          id         object ID
 154  *
 155  *               HPROF_GC_ROOT_THREAD_OBJ      thread object
 156  *
 157  *                          id         thread object ID  (may be 0 for a
 158  *                                     thread newly attached through JNI)
 159  *                          u4         thread sequence number
 160  *                          u4         stack trace sequence number
 161  *
 162  *               HPROF_GC_ROOT_JNI_GLOBAL      JNI global ref root
 163  *
 164  *                          id         object ID
 165  *                          id         JNI global ref ID
 166  *
 167  *               HPROF_GC_ROOT_JNI_LOCAL       JNI local ref
 168  *
 169  *                          id         object ID
 170  *                          u4         thread serial number
 171  *                          u4         frame # in stack trace (-1 for empty)
 172  *
 173  *               HPROF_GC_ROOT_JAVA_FRAME      Java stack frame
 174  *
 175  *                          id         object ID
 176  *                          u4         thread serial number
 177  *                          u4         frame # in stack trace (-1 for empty)
 178  *
 179  *               HPROF_GC_ROOT_NATIVE_STACK    Native stack
 180  *
 181  *                          id         object ID
 182  *                          u4         thread serial number
 183  *
 184  *               HPROF_GC_ROOT_STICKY_CLASS    System class
 185  *
 186  *                          id         object ID
 187  *
 188  *               HPROF_GC_ROOT_THREAD_BLOCK    Reference from thread block
 189  *
 190  *                          id         object ID
 191  *                          u4         thread serial number
 192  *
 193  *               HPROF_GC_ROOT_MONITOR_USED    Busy monitor
 194  *
 195  *                          id         object ID
 196  *
 197  *               HPROF_GC_CLASS_DUMP           dump of a class object
 198  *
 199  *                          id         class object ID
 200  *                          u4         stack trace serial number
 201  *                          id         super class object ID
 202  *                          id         class loader object ID
 203  *                          id         signers object ID
 204  *                          id         protection domain object ID
 205  *                          id         reserved
 206  *                          id         reserved
 207  *
 208  *                          u4         instance size (in bytes)
 209  *
 210  *                          u2         size of constant pool
 211  *                          [u2,       constant pool index,
 212  *                           ty,       type
 213  *                                     2:  object
 214  *                                     4:  boolean
 215  *                                     5:  char
 216  *                                     6:  float
 217  *                                     7:  double
 218  *                                     8:  byte
 219  *                                     9:  short
 220  *                                     10: int
 221  *                                     11: long
 222  *                           vl]*      and value
 223  *
 224  *                          u2         number of static fields
 225  *                          [id,       static field name,
 226  *                           ty,       type,
 227  *                           vl]*      and value
 228  *
 229  *                          u2         number of inst. fields (not inc. super)
 230  *                          [id,       instance field name,
 231  *                           ty]*      type
 232  *
 233  *               HPROF_GC_INSTANCE_DUMP        dump of a normal object
 234  *
 235  *                          id         object ID
 236  *                          u4         stack trace serial number
 237  *                          id         class object ID
 238  *                          u4         number of bytes that follow
 239  *                          [vl]*      instance field values (class, followed
 240  *                                     by super, super's super ...)
 241  *
 242  *               HPROF_GC_OBJ_ARRAY_DUMP       dump of an object array
 243  *
 244  *                          id         array object ID
 245  *                          u4         stack trace serial number
 246  *                          u4         number of elements
 247  *                          id         array class ID
 248  *                          [id]*      elements
 249  *
 250  *               HPROF_GC_PRIM_ARRAY_DUMP      dump of a primitive array
 251  *
 252  *                          id         array object ID
 253  *                          u4         stack trace serial number
 254  *                          u4         number of elements
 255  *                          u1         element type
 256  *                                     4:  boolean array
 257  *                                     5:  char array
 258  *                                     6:  float array
 259  *                                     7:  double array
 260  *                                     8:  byte array
 261  *                                     9:  short array
 262  *                                     10: int array
 263  *                                     11: long array
 264  *                          [u1]*      elements
 265  *
 266  * HPROF_CPU_SAMPLES        a set of sample traces of running threads
 267  *
 268  *                u4        total number of samples
 269  *                u4        # of traces
 270  *               [u4        # of samples
 271  *                u4]*      stack trace serial number
 272  *
 273  * HPROF_CONTROL_SETTINGS   the settings of on/off switches
 274  *
 275  *                u4        0x00000001: alloc traces on/off
 276  *                          0x00000002: cpu sampling on/off
 277  *                u2        stack trace depth
 278  *
 279  *
 280  * When the header is "JAVA PROFILE 1.0.2" a heap dump can optionally
 281  * be generated as a sequence of heap dump segments. This sequence is
 282  * terminated by an end record. The additional tags allowed by format
 283  * "JAVA PROFILE 1.0.2" are:
 284  *
 285  * HPROF_HEAP_DUMP_SEGMENT  denote a heap dump segment
 286  *
 287  *               [heap dump sub-records]*
 288  *               The same sub-record types allowed by HPROF_HEAP_DUMP
 289  *
 290  * HPROF_HEAP_DUMP_END      denotes the end of a heap dump
 291  *
 292  */
 293 
 294 
 295 // HPROF tags
 296 
 297 typedef enum {
 298   // top-level records
 299   HPROF_UTF8                    = 0x01,
 300   HPROF_LOAD_CLASS              = 0x02,
 301   HPROF_UNLOAD_CLASS            = 0x03,
 302   HPROF_FRAME                   = 0x04,
 303   HPROF_TRACE                   = 0x05,
 304   HPROF_ALLOC_SITES             = 0x06,
 305   HPROF_HEAP_SUMMARY            = 0x07,
 306   HPROF_START_THREAD            = 0x0A,
 307   HPROF_END_THREAD              = 0x0B,
 308   HPROF_HEAP_DUMP               = 0x0C,
 309   HPROF_CPU_SAMPLES             = 0x0D,
 310   HPROF_CONTROL_SETTINGS        = 0x0E,
 311 
 312   // 1.0.2 record types
 313   HPROF_HEAP_DUMP_SEGMENT       = 0x1C,
 314   HPROF_HEAP_DUMP_END           = 0x2C,
 315 
 316   // field types
 317   HPROF_ARRAY_OBJECT            = 0x01,
 318   HPROF_NORMAL_OBJECT           = 0x02,
 319   HPROF_BOOLEAN                 = 0x04,
 320   HPROF_CHAR                    = 0x05,
 321   HPROF_FLOAT                   = 0x06,
 322   HPROF_DOUBLE                  = 0x07,
 323   HPROF_BYTE                    = 0x08,
 324   HPROF_SHORT                   = 0x09,
 325   HPROF_INT                     = 0x0A,
 326   HPROF_LONG                    = 0x0B,
 327 
 328   // data-dump sub-records
 329   HPROF_GC_ROOT_UNKNOWN         = 0xFF,
 330   HPROF_GC_ROOT_JNI_GLOBAL      = 0x01,
 331   HPROF_GC_ROOT_JNI_LOCAL       = 0x02,
 332   HPROF_GC_ROOT_JAVA_FRAME      = 0x03,
 333   HPROF_GC_ROOT_NATIVE_STACK    = 0x04,
 334   HPROF_GC_ROOT_STICKY_CLASS    = 0x05,
 335   HPROF_GC_ROOT_THREAD_BLOCK    = 0x06,
 336   HPROF_GC_ROOT_MONITOR_USED    = 0x07,
 337   HPROF_GC_ROOT_THREAD_OBJ      = 0x08,
 338   HPROF_GC_CLASS_DUMP           = 0x20,
 339   HPROF_GC_INSTANCE_DUMP        = 0x21,
 340   HPROF_GC_OBJ_ARRAY_DUMP       = 0x22,
 341   HPROF_GC_PRIM_ARRAY_DUMP      = 0x23
 342 } hprofTag;
 343 
 344 // Default stack trace ID (used for dummy HPROF_TRACE record)
 345 enum {
 346   STACK_TRACE_ID = 1,
 347   INITIAL_CLASS_COUNT = 200
 348 };
 349 
 350 // Supports I/O operations on a dump file
 351 
 352 class DumpWriter : public StackObj {
 353  private:
 354   enum {
 355     io_buffer_size  = 8*M
 356   };
 357 
 358   int _fd;              // file descriptor (-1 if dump file not open)
 359   jlong _bytes_written; // number of byte written to dump file
 360 
 361   char* _buffer;    // internal buffer
 362   int _size;
 363   int _pos;
 364 
 365   char* _error;   // error message when I/O fails
 366 
 367   void set_file_descriptor(int fd)              { _fd = fd; }
 368   int file_descriptor() const                   { return _fd; }
 369 
 370   char* buffer() const                          { return _buffer; }
 371   int buffer_size() const                       { return _size; }
 372   int position() const                          { return _pos; }
 373   void set_position(int pos)                    { _pos = pos; }
 374 
 375   void set_error(const char* error)             { _error = (char*)os::strdup(error); }
 376 
 377   // all I/O go through this function
 378   void write_internal(void* s, int len);
 379 
 380  public:
 381   DumpWriter(const char* path);
 382   ~DumpWriter();
 383 
 384   void close();
 385   bool is_open() const                  { return file_descriptor() >= 0; }
 386   void flush();
 387 
 388   // total number of bytes written to the disk
 389   jlong bytes_written() const           { return _bytes_written; }
 390 
 391   // adjust the number of bytes written to disk (used to keep the count
 392   // of the number of bytes written in case of rewrites)
 393   void adjust_bytes_written(jlong n)     { _bytes_written += n; }
 394 
 395   // number of (buffered) bytes as yet unwritten to the dump file
 396   jlong bytes_unwritten() const          { return (jlong)position(); }
 397 
 398   char* error() const                   { return _error; }
 399 
 400   jlong current_offset();
 401   void seek_to_offset(jlong pos);
 402 
 403   // writer functions
 404   void write_raw(void* s, int len);
 405   void write_u1(u1 x)                   { write_raw((void*)&x, 1); }
 406   void write_u2(u2 x);
 407   void write_u4(u4 x);
 408   void write_u8(u8 x);
 409   void write_objectID(oop o);
 410   void write_classID(Klass* k);
 411   void write_id(u4 x);
 412 };
 413 
 414 DumpWriter::DumpWriter(const char* path) {
 415   // try to allocate an I/O buffer of io_buffer_size. If there isn't
 416   // sufficient memory then reduce size until we can allocate something.
 417   _size = io_buffer_size;
 418   do {
 419     _buffer = (char*)os::malloc(_size);
 420     if (_buffer == NULL) {
 421       _size = _size >> 1;
 422     }
 423   } while (_buffer == NULL && _size > 0);
 424   assert((_size > 0 && _buffer != NULL) || (_size == 0 && _buffer == NULL), "sanity check");
 425   _pos = 0;
 426   _error = NULL;
 427   _bytes_written = 0L;
 428   _fd = os::create_binary_file(path, false);    // don't replace existing file
 429 
 430   // if the open failed we record the error
 431   if (_fd < 0) {
 432     _error = (char*)os::strdup(strerror(errno));
 433   }
 434 }
 435 
 436 DumpWriter::~DumpWriter() {
 437   // flush and close dump file
 438   if (file_descriptor() >= 0) {
 439     close();
 440   }
 441   if (_buffer != NULL) os::free(_buffer);
 442   if (_error != NULL) os::free(_error);
 443 }
 444 
 445 // closes dump file (if open)
 446 void DumpWriter::close() {
 447   // flush and close dump file
 448   if (file_descriptor() >= 0) {
 449     flush();
 450     ::close(file_descriptor());
 451   }
 452 }
 453 
 454 // write directly to the file
 455 void DumpWriter::write_internal(void* s, int len) {
 456   if (is_open()) {
 457     int n = ::write(file_descriptor(), s, len);
 458     if (n > 0) {
 459       _bytes_written += n;
 460     }
 461     if (n != len) {
 462       if (n < 0) {
 463         set_error(strerror(errno));
 464       } else {
 465         set_error("file size limit");
 466       }
 467       ::close(file_descriptor());
 468       set_file_descriptor(-1);
 469     }
 470   }
 471 }
 472 
 473 // write raw bytes
 474 void DumpWriter::write_raw(void* s, int len) {
 475   if (is_open()) {
 476     // flush buffer to make toom
 477     if ((position()+ len) >= buffer_size()) {
 478       flush();
 479     }
 480 
 481     // buffer not available or too big to buffer it
 482     if ((buffer() == NULL) || (len >= buffer_size())) {
 483       write_internal(s, len);
 484     } else {
 485       // Should optimize this for u1/u2/u4/u8 sizes.
 486       memcpy(buffer() + position(), s, len);
 487       set_position(position() + len);
 488     }
 489   }
 490 }
 491 
 492 // flush any buffered bytes to the file
 493 void DumpWriter::flush() {
 494   if (is_open() && position() > 0) {
 495     write_internal(buffer(), position());
 496     set_position(0);
 497   }
 498 }
 499 
 500 
 501 jlong DumpWriter::current_offset() {
 502   if (is_open()) {
 503     // the offset is the file offset plus whatever we have buffered
 504     jlong offset = os::current_file_offset(file_descriptor());
 505     assert(offset >= 0, "lseek failed");
 506     return offset + (jlong)position();
 507   } else {
 508     return (jlong)-1;
 509   }
 510 }
 511 
 512 void DumpWriter::seek_to_offset(jlong off) {
 513   assert(off >= 0, "bad offset");
 514 
 515   // need to flush before seeking
 516   flush();
 517 
 518   // may be closed due to I/O error
 519   if (is_open()) {
 520     jlong n = os::seek_to_file_offset(file_descriptor(), off);
 521     assert(n >= 0, "lseek failed");
 522   }
 523 }
 524 
 525 void DumpWriter::write_u2(u2 x) {
 526   u2 v;
 527   Bytes::put_Java_u2((address)&v, x);
 528   write_raw((void*)&v, 2);
 529 }
 530 
 531 void DumpWriter::write_u4(u4 x) {
 532   u4 v;
 533   Bytes::put_Java_u4((address)&v, x);
 534   write_raw((void*)&v, 4);
 535 }
 536 
 537 void DumpWriter::write_u8(u8 x) {
 538   u8 v;
 539   Bytes::put_Java_u8((address)&v, x);
 540   write_raw((void*)&v, 8);
 541 }
 542 
 543 void DumpWriter::write_objectID(oop o) {
 544   address a = (address)((uintptr_t)o);
 545 #ifdef _LP64
 546   write_u8((u8)a);
 547 #else
 548   write_u4((u4)a);
 549 #endif
 550 }
 551 
 552 void DumpWriter::write_id(u4 x) {
 553 #ifdef _LP64
 554   write_u8((u8) x);
 555 #else
 556   write_u4(x);
 557 #endif
 558 }
 559 
 560 // We use java mirror as the class ID
 561 void DumpWriter::write_classID(Klass* k) {
 562   write_objectID(k->java_mirror());
 563 }
 564 
 565 
 566 
 567 // Support class with a collection of functions used when dumping the heap
 568 
 569 class DumperSupport : AllStatic {
 570  public:
 571 
 572   // write a header of the given type
 573   static void write_header(DumpWriter* writer, hprofTag tag, u4 len);
 574 
 575   // returns hprof tag for the given type signature
 576   static hprofTag sig2tag(symbolOop sig);
 577   // returns hprof tag for the given basic type
 578   static hprofTag type2tag(BasicType type);
 579 
 580   // returns the size of the instance of the given class
 581   static u4 instance_size(klassOop k);
 582 
 583   // dump a jfloat
 584   static void dump_float(DumpWriter* writer, jfloat f);
 585   // dump a jdouble
 586   static void dump_double(DumpWriter* writer, jdouble d);
 587   // dumps the raw value of the given field
 588   static void dump_field_value(DumpWriter* writer, char type, address addr);
 589   // dumps static fields of the given class
 590   static void dump_static_fields(DumpWriter* writer, klassOop k);
 591   // dump the raw values of the instance fields of the given object
 592   static void dump_instance_fields(DumpWriter* writer, oop o);
 593   // dumps the definition of the instance fields for a given class
 594   static void dump_instance_field_descriptors(DumpWriter* writer, klassOop k);
 595   // creates HPROF_GC_INSTANCE_DUMP record for the given object
 596   static void dump_instance(DumpWriter* writer, oop o);
 597   // creates HPROF_GC_CLASS_DUMP record for the given class and each of its
 598   // array classes
 599   static void dump_class_and_array_classes(DumpWriter* writer, klassOop k);
 600   // creates HPROF_GC_CLASS_DUMP record for a given primitive array
 601   // class (and each multi-dimensional array class too)
 602   static void dump_basic_type_array_class(DumpWriter* writer, klassOop k);
 603 
 604   // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
 605   static void dump_object_array(DumpWriter* writer, objArrayOop array);
 606   // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
 607   static void dump_prim_array(DumpWriter* writer, typeArrayOop array);
 608   // create HPROF_FRAME record for the given method and bci
 609   static void dump_stack_frame(DumpWriter* writer, int frame_serial_num, int class_serial_num, methodOop m, int bci);
 610 };
 611 
 612 // write a header of the given type
 613 void DumperSupport:: write_header(DumpWriter* writer, hprofTag tag, u4 len) {
 614   writer->write_u1((u1)tag);
 615   writer->write_u4(0);                  // current ticks
 616   writer->write_u4(len);
 617 }
 618 
 619 // returns hprof tag for the given type signature
 620 hprofTag DumperSupport::sig2tag(symbolOop sig) {
 621   switch (sig->byte_at(0)) {
 622     case JVM_SIGNATURE_CLASS    : return HPROF_NORMAL_OBJECT;
 623     case JVM_SIGNATURE_ARRAY    : return HPROF_NORMAL_OBJECT;
 624     case JVM_SIGNATURE_BYTE     : return HPROF_BYTE;
 625     case JVM_SIGNATURE_CHAR     : return HPROF_CHAR;
 626     case JVM_SIGNATURE_FLOAT    : return HPROF_FLOAT;
 627     case JVM_SIGNATURE_DOUBLE   : return HPROF_DOUBLE;
 628     case JVM_SIGNATURE_INT      : return HPROF_INT;
 629     case JVM_SIGNATURE_LONG     : return HPROF_LONG;
 630     case JVM_SIGNATURE_SHORT    : return HPROF_SHORT;
 631     case JVM_SIGNATURE_BOOLEAN  : return HPROF_BOOLEAN;
 632     default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
 633   }
 634 }
 635 
 636 hprofTag DumperSupport::type2tag(BasicType type) {
 637   switch (type) {
 638     case T_BYTE     : return HPROF_BYTE;
 639     case T_CHAR     : return HPROF_CHAR;
 640     case T_FLOAT    : return HPROF_FLOAT;
 641     case T_DOUBLE   : return HPROF_DOUBLE;
 642     case T_INT      : return HPROF_INT;
 643     case T_LONG     : return HPROF_LONG;
 644     case T_SHORT    : return HPROF_SHORT;
 645     case T_BOOLEAN  : return HPROF_BOOLEAN;
 646     default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
 647   }
 648 }
 649 
 650 // dump a jfloat
 651 void DumperSupport::dump_float(DumpWriter* writer, jfloat f) {
 652   if (g_isnan(f)) {
 653     writer->write_u4(0x7fc00000);    // collapsing NaNs
 654   } else {
 655     union {
 656       int i;
 657       float f;
 658     } u;
 659     u.f = (float)f;
 660     writer->write_u4((u4)u.i);
 661   }
 662 }
 663 
 664 // dump a jdouble
 665 void DumperSupport::dump_double(DumpWriter* writer, jdouble d) {
 666   union {
 667     jlong l;
 668     double d;
 669   } u;
 670   if (g_isnan(d)) {                 // collapsing NaNs
 671     u.l = (jlong)(0x7ff80000);
 672     u.l = (u.l << 32);
 673   } else {
 674     u.d = (double)d;
 675   }
 676   writer->write_u8((u8)u.l);
 677 }
 678 
 679 // dumps the raw value of the given field
 680 void DumperSupport::dump_field_value(DumpWriter* writer, char type, address addr) {
 681   switch (type) {
 682     case JVM_SIGNATURE_CLASS :
 683     case JVM_SIGNATURE_ARRAY : {
 684       oop o;
 685       if (UseCompressedOops) {
 686         o = oopDesc::load_decode_heap_oop((narrowOop*)addr);
 687       } else {
 688         o = oopDesc::load_decode_heap_oop((oop*)addr);
 689       }
 690 
 691       // reflection and sun.misc.Unsafe classes may have a reference to a
 692       // klassOop so filter it out.
 693       if (o != NULL && o->is_klass()) {
 694         o = NULL;
 695       }
 696 
 697       // FIXME: When sharing is enabled we don't emit field references to objects
 698       // in shared spaces. We can remove this once we write records for the classes
 699       // and strings that are shared.
 700       if (o != NULL && o->is_shared()) {
 701         o = NULL;
 702       }
 703       writer->write_objectID(o);
 704       break;
 705     }
 706     case JVM_SIGNATURE_BYTE     : {
 707       jbyte* b = (jbyte*)addr;
 708       writer->write_u1((u1)*b);
 709       break;
 710     }
 711     case JVM_SIGNATURE_CHAR     : {
 712       jchar* c = (jchar*)addr;
 713       writer->write_u2((u2)*c);
 714       break;
 715     }
 716     case JVM_SIGNATURE_SHORT : {
 717       jshort* s = (jshort*)addr;
 718       writer->write_u2((u2)*s);
 719       break;
 720     }
 721     case JVM_SIGNATURE_FLOAT : {
 722       jfloat* f = (jfloat*)addr;
 723       dump_float(writer, *f);
 724       break;
 725     }
 726     case JVM_SIGNATURE_DOUBLE : {
 727       jdouble* f = (jdouble*)addr;
 728       dump_double(writer, *f);
 729       break;
 730     }
 731     case JVM_SIGNATURE_INT : {
 732       jint* i = (jint*)addr;
 733       writer->write_u4((u4)*i);
 734       break;
 735     }
 736     case JVM_SIGNATURE_LONG     : {
 737       jlong* l = (jlong*)addr;
 738       writer->write_u8((u8)*l);
 739       break;
 740     }
 741     case JVM_SIGNATURE_BOOLEAN : {
 742       jboolean* b = (jboolean*)addr;
 743       writer->write_u1((u1)*b);
 744       break;
 745     }
 746     default : ShouldNotReachHere();
 747   }
 748 }
 749 
 750 // returns the size of the instance of the given class
 751 u4 DumperSupport::instance_size(klassOop k) {
 752   HandleMark hm;
 753   instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), k);
 754 
 755   int size = 0;
 756 
 757   for (FieldStream fld(ikh, false, false); !fld.eos(); fld.next()) {
 758     if (!fld.access_flags().is_static()) {
 759       symbolOop sig = fld.signature();
 760       switch (sig->byte_at(0)) {
 761         case JVM_SIGNATURE_CLASS   :
 762         case JVM_SIGNATURE_ARRAY   : size += oopSize; break;
 763 
 764         case JVM_SIGNATURE_BYTE    :
 765         case JVM_SIGNATURE_BOOLEAN : size += 1; break;
 766 
 767         case JVM_SIGNATURE_CHAR    :
 768         case JVM_SIGNATURE_SHORT   : size += 2; break;
 769 
 770         case JVM_SIGNATURE_INT     :
 771         case JVM_SIGNATURE_FLOAT   : size += 4; break;
 772 
 773         case JVM_SIGNATURE_LONG    :
 774         case JVM_SIGNATURE_DOUBLE  : size += 8; break;
 775 
 776         default : ShouldNotReachHere();
 777       }
 778     }
 779   }
 780   return (u4)size;
 781 }
 782 
 783 // dumps static fields of the given class
 784 void DumperSupport::dump_static_fields(DumpWriter* writer, klassOop k) {
 785   HandleMark hm;
 786   instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), k);
 787 
 788   // pass 1 - count the static fields
 789   u2 field_count = 0;
 790   for (FieldStream fldc(ikh, true, true); !fldc.eos(); fldc.next()) {
 791     if (fldc.access_flags().is_static()) field_count++;
 792   }
 793 
 794   writer->write_u2(field_count);
 795 
 796   // pass 2 - dump the field descriptors and raw values
 797   for (FieldStream fld(ikh, true, true); !fld.eos(); fld.next()) {
 798     if (fld.access_flags().is_static()) {
 799       symbolOop sig = fld.signature();
 800 
 801       writer->write_objectID(fld.name());   // name
 802       writer->write_u1(sig2tag(sig));       // type
 803 
 804       // value
 805       int offset = fld.offset();
 806       address addr = (address)k + offset;
 807 
 808       dump_field_value(writer, sig->byte_at(0), addr);
 809     }
 810   }
 811 }
 812 
 813 // dump the raw values of the instance fields of the given object
 814 void DumperSupport::dump_instance_fields(DumpWriter* writer, oop o) {
 815   HandleMark hm;
 816   instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), o->klass());
 817 
 818   for (FieldStream fld(ikh, false, false); !fld.eos(); fld.next()) {
 819     if (!fld.access_flags().is_static()) {
 820       symbolOop sig = fld.signature();
 821       address addr = (address)o + fld.offset();
 822 
 823       dump_field_value(writer, sig->byte_at(0), addr);
 824     }
 825   }
 826 }
 827 
 828 // dumps the definition of the instance fields for a given class
 829 void DumperSupport::dump_instance_field_descriptors(DumpWriter* writer, klassOop k) {
 830   HandleMark hm;
 831   instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), k);
 832 
 833   // pass 1 - count the instance fields
 834   u2 field_count = 0;
 835   for (FieldStream fldc(ikh, true, true); !fldc.eos(); fldc.next()) {
 836     if (!fldc.access_flags().is_static()) field_count++;
 837   }
 838 
 839   writer->write_u2(field_count);
 840 
 841   // pass 2 - dump the field descriptors
 842   for (FieldStream fld(ikh, true, true); !fld.eos(); fld.next()) {
 843     if (!fld.access_flags().is_static()) {
 844       symbolOop sig = fld.signature();
 845 
 846       writer->write_objectID(fld.name());                   // name
 847       writer->write_u1(sig2tag(sig));       // type
 848     }
 849   }
 850 }
 851 
 852 // creates HPROF_GC_INSTANCE_DUMP record for the given object
 853 void DumperSupport::dump_instance(DumpWriter* writer, oop o) {
 854   klassOop k = o->klass();
 855 
 856   writer->write_u1(HPROF_GC_INSTANCE_DUMP);
 857   writer->write_objectID(o);
 858   writer->write_u4(STACK_TRACE_ID);
 859 
 860   // class ID
 861   writer->write_classID(Klass::cast(k));
 862 
 863   // number of bytes that follow
 864   writer->write_u4(instance_size(k) );
 865 
 866   // field values
 867   dump_instance_fields(writer, o);
 868 }
 869 
 870 // creates HPROF_GC_CLASS_DUMP record for the given class and each of
 871 // its array classes
 872 void DumperSupport::dump_class_and_array_classes(DumpWriter* writer, klassOop k) {
 873   Klass* klass = Klass::cast(k);
 874   assert(klass->oop_is_instance(), "not an instanceKlass");
 875   instanceKlass* ik = (instanceKlass*)klass;
 876 
 877   writer->write_u1(HPROF_GC_CLASS_DUMP);
 878 
 879   // class ID
 880   writer->write_classID(ik);
 881   writer->write_u4(STACK_TRACE_ID);
 882 
 883   // super class ID
 884   klassOop java_super = ik->java_super();
 885   if (java_super == NULL) {
 886     writer->write_objectID(NULL);
 887   } else {
 888     writer->write_classID(Klass::cast(java_super));
 889   }
 890 
 891   writer->write_objectID(ik->class_loader());
 892   writer->write_objectID(ik->signers());
 893   writer->write_objectID(ik->protection_domain());
 894 
 895   // reserved
 896   writer->write_objectID(NULL);
 897   writer->write_objectID(NULL);
 898 
 899   // instance size
 900   writer->write_u4(DumperSupport::instance_size(k));
 901 
 902   // size of constant pool - ignored by HAT 1.1
 903   writer->write_u2(0);
 904 
 905   // number of static fields
 906   dump_static_fields(writer, k);
 907 
 908   // description of instance fields
 909   dump_instance_field_descriptors(writer, k);
 910 
 911   // array classes
 912   k = klass->array_klass_or_null();
 913   while (k != NULL) {
 914     Klass* klass = Klass::cast(k);
 915     assert(klass->oop_is_objArray(), "not an objArrayKlass");
 916 
 917     writer->write_u1(HPROF_GC_CLASS_DUMP);
 918     writer->write_classID(klass);
 919     writer->write_u4(STACK_TRACE_ID);
 920 
 921     // super class of array classes is java.lang.Object
 922     java_super = klass->java_super();
 923     assert(java_super != NULL, "checking");
 924     writer->write_classID(Klass::cast(java_super));
 925 
 926     writer->write_objectID(ik->class_loader());
 927     writer->write_objectID(ik->signers());
 928     writer->write_objectID(ik->protection_domain());
 929 
 930     writer->write_objectID(NULL);    // reserved
 931     writer->write_objectID(NULL);
 932     writer->write_u4(0);             // instance size
 933     writer->write_u2(0);             // constant pool
 934     writer->write_u2(0);             // static fields
 935     writer->write_u2(0);             // instance fields
 936 
 937     // get the array class for the next rank
 938     k = klass->array_klass_or_null();
 939   }
 940 }
 941 
 942 // creates HPROF_GC_CLASS_DUMP record for a given primitive array
 943 // class (and each multi-dimensional array class too)
 944 void DumperSupport::dump_basic_type_array_class(DumpWriter* writer, klassOop k) {
 945  // array classes
 946  while (k != NULL) {
 947     Klass* klass = Klass::cast(k);
 948 
 949     writer->write_u1(HPROF_GC_CLASS_DUMP);
 950     writer->write_classID(klass);
 951     writer->write_u4(STACK_TRACE_ID);
 952 
 953     // super class of array classes is java.lang.Object
 954     klassOop java_super = klass->java_super();
 955     assert(java_super != NULL, "checking");
 956     writer->write_classID(Klass::cast(java_super));
 957 
 958     writer->write_objectID(NULL);    // loader
 959     writer->write_objectID(NULL);    // signers
 960     writer->write_objectID(NULL);    // protection domain
 961 
 962     writer->write_objectID(NULL);    // reserved
 963     writer->write_objectID(NULL);
 964     writer->write_u4(0);             // instance size
 965     writer->write_u2(0);             // constant pool
 966     writer->write_u2(0);             // static fields
 967     writer->write_u2(0);             // instance fields
 968 
 969     // get the array class for the next rank
 970     k = klass->array_klass_or_null();
 971   }
 972 }
 973 
 974 // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
 975 void DumperSupport::dump_object_array(DumpWriter* writer, objArrayOop array) {
 976 
 977   // filter this
 978   if (array->klass() == Universe::systemObjArrayKlassObj()) return;
 979 
 980   writer->write_u1(HPROF_GC_OBJ_ARRAY_DUMP);
 981   writer->write_objectID(array);
 982   writer->write_u4(STACK_TRACE_ID);
 983   writer->write_u4((u4)array->length());
 984 
 985   // array class ID
 986   writer->write_classID(Klass::cast(array->klass()));
 987 
 988   // [id]* elements
 989   for (int index=0; index<array->length(); index++) {
 990     oop o = array->obj_at(index);
 991     writer->write_objectID(o);
 992   }
 993 }
 994 
 995 #define WRITE_ARRAY(Array, Type, Size) \
 996   for (int i=0; i<Array->length(); i++) { writer->write_##Size((Size)array->Type##_at(i)); }
 997 
 998 
 999 // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
1000 void DumperSupport::dump_prim_array(DumpWriter* writer, typeArrayOop array) {
1001   BasicType type = typeArrayKlass::cast(array->klass())->element_type();
1002 
1003   writer->write_u1(HPROF_GC_PRIM_ARRAY_DUMP);
1004   writer->write_objectID(array);
1005   writer->write_u4(STACK_TRACE_ID);
1006   writer->write_u4((u4)array->length());
1007   writer->write_u1(type2tag(type));
1008 
1009   // nothing to copy
1010   if (array->length() == 0) {
1011     return;
1012   }
1013 
1014   // If the byte ordering is big endian then we can copy most types directly
1015   int length_in_bytes = array->length() * type2aelembytes(type);
1016   assert(length_in_bytes > 0, "nothing to copy");
1017 
1018   switch (type) {
1019     case T_INT : {
1020       if (Bytes::is_Java_byte_ordering_different()) {
1021         WRITE_ARRAY(array, int, u4);
1022       } else {
1023         writer->write_raw((void*)(array->int_at_addr(0)), length_in_bytes);
1024       }
1025       break;
1026     }
1027     case T_BYTE : {
1028       writer->write_raw((void*)(array->byte_at_addr(0)), length_in_bytes);
1029       break;
1030     }
1031     case T_CHAR : {
1032       if (Bytes::is_Java_byte_ordering_different()) {
1033         WRITE_ARRAY(array, char, u2);
1034       } else {
1035         writer->write_raw((void*)(array->char_at_addr(0)), length_in_bytes);
1036       }
1037       break;
1038     }
1039     case T_SHORT : {
1040       if (Bytes::is_Java_byte_ordering_different()) {
1041         WRITE_ARRAY(array, short, u2);
1042       } else {
1043         writer->write_raw((void*)(array->short_at_addr(0)), length_in_bytes);
1044       }
1045       break;
1046     }
1047     case T_BOOLEAN : {
1048       if (Bytes::is_Java_byte_ordering_different()) {
1049         WRITE_ARRAY(array, bool, u1);
1050       } else {
1051         writer->write_raw((void*)(array->bool_at_addr(0)), length_in_bytes);
1052       }
1053       break;
1054     }
1055     case T_LONG : {
1056       if (Bytes::is_Java_byte_ordering_different()) {
1057         WRITE_ARRAY(array, long, u8);
1058       } else {
1059         writer->write_raw((void*)(array->long_at_addr(0)), length_in_bytes);
1060       }
1061       break;
1062     }
1063 
1064     // handle float/doubles in a special value to ensure than NaNs are
1065     // written correctly. TO DO: Check if we can avoid this on processors that
1066     // use IEEE 754.
1067 
1068     case T_FLOAT : {
1069       for (int i=0; i<array->length(); i++) {
1070         dump_float( writer, array->float_at(i) );
1071       }
1072       break;
1073     }
1074     case T_DOUBLE : {
1075       for (int i=0; i<array->length(); i++) {
1076         dump_double( writer, array->double_at(i) );
1077       }
1078       break;
1079     }
1080     default : ShouldNotReachHere();
1081   }
1082 }
1083 
1084 // create a HPROF_FRAME record of the given methodOop and bci
1085 void DumperSupport::dump_stack_frame(DumpWriter* writer,
1086                                      int frame_serial_num,
1087                                      int class_serial_num,
1088                                      methodOop m,
1089                                      int bci) {
1090   int line_number;
1091   if (m->is_native()) {
1092     line_number = -3;  // native frame
1093   } else {
1094     line_number = m->line_number_from_bci(bci);
1095   }
1096 
1097   write_header(writer, HPROF_FRAME, 4*oopSize + 2*sizeof(u4));
1098   writer->write_id(frame_serial_num);               // frame serial number
1099   writer->write_objectID(m->name());                // method's name
1100   writer->write_objectID(m->signature());           // method's signature
1101 
1102   assert(Klass::cast(m->method_holder())->oop_is_instance(), "not instanceKlass");
1103   writer->write_objectID(instanceKlass::cast(m->method_holder())->source_file_name());  // source file name
1104   writer->write_u4(class_serial_num);               // class serial number
1105   writer->write_u4((u4) line_number);               // line number
1106 }
1107 
1108 // Support class used to generate HPROF_UTF8 records from the entries in the
1109 // SymbolTable.
1110 
1111 class SymbolTableDumper : public OopClosure {
1112  private:
1113   DumpWriter* _writer;
1114   DumpWriter* writer() const                { return _writer; }
1115  public:
1116   SymbolTableDumper(DumpWriter* writer)     { _writer = writer; }
1117   void do_oop(oop* obj_p);
1118   void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1119 };
1120 
1121 void SymbolTableDumper::do_oop(oop* obj_p) {
1122   ResourceMark rm;
1123   symbolOop sym = (symbolOop)*obj_p;
1124 
1125   int len = sym->utf8_length();
1126   if (len > 0) {
1127     char* s = sym->as_utf8();
1128     DumperSupport::write_header(writer(), HPROF_UTF8, oopSize + len);
1129     writer()->write_objectID(sym);
1130     writer()->write_raw(s, len);
1131   }
1132 }
1133 
1134 
1135 // Support class used to generate HPROF_GC_ROOT_JNI_LOCAL records
1136 
1137 class JNILocalsDumper : public OopClosure {
1138  private:
1139   DumpWriter* _writer;
1140   u4 _thread_serial_num;
1141   int _frame_num;
1142   DumpWriter* writer() const                { return _writer; }
1143  public:
1144   JNILocalsDumper(DumpWriter* writer, u4 thread_serial_num) {
1145     _writer = writer;
1146     _thread_serial_num = thread_serial_num;
1147     _frame_num = -1;  // default - empty stack
1148   }
1149   void set_frame_number(int n) { _frame_num = n; }
1150   void do_oop(oop* obj_p);
1151   void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1152 };
1153 
1154 
1155 void JNILocalsDumper::do_oop(oop* obj_p) {
1156   // ignore null or deleted handles
1157   oop o = *obj_p;
1158   if (o != NULL && o != JNIHandles::deleted_handle()) {
1159     writer()->write_u1(HPROF_GC_ROOT_JNI_LOCAL);
1160     writer()->write_objectID(o);
1161     writer()->write_u4(_thread_serial_num);
1162     writer()->write_u4((u4)_frame_num);
1163   }
1164 }
1165 
1166 
1167 // Support class used to generate HPROF_GC_ROOT_JNI_GLOBAL records
1168 
1169 class JNIGlobalsDumper : public OopClosure {
1170  private:
1171   DumpWriter* _writer;
1172   DumpWriter* writer() const                { return _writer; }
1173 
1174  public:
1175   JNIGlobalsDumper(DumpWriter* writer) {
1176     _writer = writer;
1177   }
1178   void do_oop(oop* obj_p);
1179   void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1180 };
1181 
1182 void JNIGlobalsDumper::do_oop(oop* obj_p) {
1183   oop o = *obj_p;
1184 
1185   // ignore these
1186   if (o == NULL || o == JNIHandles::deleted_handle()) return;
1187 
1188   // we ignore global ref to symbols and other internal objects
1189   if (o->is_instance() || o->is_objArray() || o->is_typeArray()) {
1190     writer()->write_u1(HPROF_GC_ROOT_JNI_GLOBAL);
1191     writer()->write_objectID(o);
1192     writer()->write_objectID((oopDesc*)obj_p);      // global ref ID
1193   }
1194 };
1195 
1196 
1197 // Support class used to generate HPROF_GC_ROOT_MONITOR_USED records
1198 
1199 class MonitorUsedDumper : public OopClosure {
1200  private:
1201   DumpWriter* _writer;
1202   DumpWriter* writer() const                { return _writer; }
1203  public:
1204   MonitorUsedDumper(DumpWriter* writer) {
1205     _writer = writer;
1206   }
1207   void do_oop(oop* obj_p) {
1208     writer()->write_u1(HPROF_GC_ROOT_MONITOR_USED);
1209     writer()->write_objectID(*obj_p);
1210   }
1211   void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1212 };
1213 
1214 
1215 // Support class used to generate HPROF_GC_ROOT_STICKY_CLASS records
1216 
1217 class StickyClassDumper : public OopClosure {
1218  private:
1219   DumpWriter* _writer;
1220   DumpWriter* writer() const                { return _writer; }
1221  public:
1222   StickyClassDumper(DumpWriter* writer) {
1223     _writer = writer;
1224   }
1225   void do_oop(oop* obj_p);
1226   void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1227 };
1228 
1229 void StickyClassDumper::do_oop(oop* obj_p) {
1230   if (*obj_p != NULL) {
1231     oop o = *obj_p;
1232     if (o->is_klass()) {
1233       klassOop k = klassOop(o);
1234       if (Klass::cast(k)->oop_is_instance()) {
1235         instanceKlass* ik = instanceKlass::cast(k);
1236         writer()->write_u1(HPROF_GC_ROOT_STICKY_CLASS);
1237         writer()->write_classID(ik);
1238       }
1239     }
1240   }
1241 }
1242 
1243 
1244 class VM_HeapDumper;
1245 
1246 // Support class using when iterating over the heap.
1247 
1248 class HeapObjectDumper : public ObjectClosure {
1249  private:
1250   VM_HeapDumper* _dumper;
1251   DumpWriter* _writer;
1252 
1253   VM_HeapDumper* dumper()               { return _dumper; }
1254   DumpWriter* writer()                  { return _writer; }
1255 
1256   // used to indicate that a record has been writen
1257   void mark_end_of_record();
1258 
1259  public:
1260   HeapObjectDumper(VM_HeapDumper* dumper, DumpWriter* writer) {
1261     _dumper = dumper;
1262     _writer = writer;
1263   }
1264 
1265   // called for each object in the heap
1266   void do_object(oop o);
1267 };
1268 
1269 void HeapObjectDumper::do_object(oop o) {
1270   // hide the sentinel for deleted handles
1271   if (o == JNIHandles::deleted_handle()) return;
1272 
1273   // ignore KlassKlass objects
1274   if (o->is_klass()) return;
1275 
1276   // skip classes as these emitted as HPROF_GC_CLASS_DUMP records
1277   if (o->klass() == SystemDictionary::Class_klass()) {
1278     if (!java_lang_Class::is_primitive(o)) {
1279       return;
1280     }
1281   }
1282 
1283   // create a HPROF_GC_INSTANCE record for each object
1284   if (o->is_instance()) {
1285     DumperSupport::dump_instance(writer(), o);
1286     mark_end_of_record();
1287   } else {
1288     // create a HPROF_GC_OBJ_ARRAY_DUMP record for each object array
1289     if (o->is_objArray()) {
1290       DumperSupport::dump_object_array(writer(), objArrayOop(o));
1291       mark_end_of_record();
1292     } else {
1293       // create a HPROF_GC_PRIM_ARRAY_DUMP record for each type array
1294       if (o->is_typeArray()) {
1295         DumperSupport::dump_prim_array(writer(), typeArrayOop(o));
1296         mark_end_of_record();
1297       }
1298     }
1299   }
1300 }
1301 
1302 // The VM operation that performs the heap dump
1303 class VM_HeapDumper : public VM_GC_Operation {
1304  private:
1305   static VM_HeapDumper* _global_dumper;
1306   static DumpWriter*    _global_writer;
1307   DumpWriter*           _local_writer;
1308   JavaThread*           _oome_thread;
1309   methodOop             _oome_constructor;
1310   bool _gc_before_heap_dump;
1311   bool _is_segmented_dump;
1312   jlong _dump_start;
1313   GrowableArray<Klass*>* _klass_map;
1314   ThreadStackTrace** _stack_traces;
1315   int _num_threads;
1316 
1317   // accessors and setters
1318   static VM_HeapDumper* dumper()         {  assert(_global_dumper != NULL, "Error"); return _global_dumper; }
1319   static DumpWriter* writer()            {  assert(_global_writer != NULL, "Error"); return _global_writer; }
1320   void set_global_dumper() {
1321     assert(_global_dumper == NULL, "Error");
1322     _global_dumper = this;
1323   }
1324   void set_global_writer() {
1325     assert(_global_writer == NULL, "Error");
1326     _global_writer = _local_writer;
1327   }
1328   void clear_global_dumper() { _global_dumper = NULL; }
1329   void clear_global_writer() { _global_writer = NULL; }
1330 
1331   bool is_segmented_dump() const                { return _is_segmented_dump; }
1332   void set_segmented_dump()                     { _is_segmented_dump = true; }
1333   jlong dump_start() const                      { return _dump_start; }
1334   void set_dump_start(jlong pos);
1335 
1336   bool skip_operation() const;
1337 
1338   // writes a HPROF_LOAD_CLASS record
1339   static void do_load_class(klassOop k);
1340 
1341   // writes a HPROF_GC_CLASS_DUMP record for the given class
1342   // (and each array class too)
1343   static void do_class_dump(klassOop k);
1344 
1345   // writes a HPROF_GC_CLASS_DUMP records for a given basic type
1346   // array (and each multi-dimensional array too)
1347   static void do_basic_type_array_class_dump(klassOop k);
1348 
1349   // HPROF_GC_ROOT_THREAD_OBJ records
1350   int do_thread(JavaThread* thread, u4 thread_serial_num);
1351   void do_threads();
1352 
1353   void add_class_serial_number(Klass* k, int serial_num) {
1354     _klass_map->at_put_grow(serial_num, k);
1355   }
1356 
1357   // HPROF_TRACE and HPROF_FRAME records
1358   void dump_stack_traces();
1359 
1360   // writes a HPROF_HEAP_DUMP or HPROF_HEAP_DUMP_SEGMENT record
1361   void write_dump_header();
1362 
1363   // fixes up the length of the current dump record
1364   void write_current_dump_record_length();
1365 
1366   // fixes up the current dump record )and writes HPROF_HEAP_DUMP_END
1367   // record in the case of a segmented heap dump)
1368   void end_of_dump();
1369 
1370  public:
1371   VM_HeapDumper(DumpWriter* writer, bool gc_before_heap_dump, bool oome) :
1372     VM_GC_Operation(0 /* total collections,      dummy, ignored */,
1373                     0 /* total full collections, dummy, ignored */,
1374                     gc_before_heap_dump) {
1375     _local_writer = writer;
1376     _gc_before_heap_dump = gc_before_heap_dump;
1377     _is_segmented_dump = false;
1378     _dump_start = (jlong)-1;
1379     _klass_map = new (ResourceObj::C_HEAP) GrowableArray<Klass*>(INITIAL_CLASS_COUNT, true);
1380     _stack_traces = NULL;
1381     _num_threads = 0;
1382     if (oome) {
1383       assert(!Thread::current()->is_VM_thread(), "Dump from OutOfMemoryError cannot be called by the VMThread");
1384       // get OutOfMemoryError zero-parameter constructor
1385       instanceKlass* oome_ik = instanceKlass::cast(SystemDictionary::OutOfMemoryError_klass());
1386       _oome_constructor = oome_ik->find_method(vmSymbols::object_initializer_name(),
1387                                                           vmSymbols::void_method_signature());
1388       // get thread throwing OOME when generating the heap dump at OOME
1389       _oome_thread = JavaThread::current();
1390     } else {
1391       _oome_thread = NULL;
1392       _oome_constructor = NULL;
1393     }
1394   }
1395   ~VM_HeapDumper() {
1396     if (_stack_traces != NULL) {
1397       for (int i=0; i < _num_threads; i++) {
1398         delete _stack_traces[i];
1399       }
1400       FREE_C_HEAP_ARRAY(ThreadStackTrace*, _stack_traces);
1401     }
1402     delete _klass_map;
1403   }
1404 
1405   VMOp_Type type() const { return VMOp_HeapDumper; }
1406   // used to mark sub-record boundary
1407   void check_segment_length();
1408   void doit();
1409 };
1410 
1411 VM_HeapDumper* VM_HeapDumper::_global_dumper = NULL;
1412 DumpWriter*    VM_HeapDumper::_global_writer = NULL;
1413 
1414 bool VM_HeapDumper::skip_operation() const {
1415   return false;
1416 }
1417 
1418 // sets the dump starting position
1419 void VM_HeapDumper::set_dump_start(jlong pos) {
1420   _dump_start = pos;
1421 }
1422 
1423  // writes a HPROF_HEAP_DUMP or HPROF_HEAP_DUMP_SEGMENT record
1424 void VM_HeapDumper::write_dump_header() {
1425   if (writer()->is_open()) {
1426     if (is_segmented_dump()) {
1427       writer()->write_u1(HPROF_HEAP_DUMP_SEGMENT);
1428     } else {
1429       writer()->write_u1(HPROF_HEAP_DUMP);
1430     }
1431     writer()->write_u4(0); // current ticks
1432 
1433     // record the starting position for the dump (its length will be fixed up later)
1434     set_dump_start(writer()->current_offset());
1435     writer()->write_u4(0);
1436   }
1437 }
1438 
1439 // fixes up the length of the current dump record
1440 void VM_HeapDumper::write_current_dump_record_length() {
1441   if (writer()->is_open()) {
1442     assert(dump_start() >= 0, "no dump start recorded");
1443 
1444     // calculate the size of the dump record
1445     jlong dump_end = writer()->current_offset();
1446     jlong dump_len = (dump_end - dump_start() - 4);
1447 
1448     // record length must fit in a u4
1449     if (dump_len > (jlong)(4L*(jlong)G)) {
1450       warning("record is too large");
1451     }
1452 
1453     // seek to the dump start and fix-up the length
1454     writer()->seek_to_offset(dump_start());
1455     writer()->write_u4((u4)dump_len);
1456 
1457     // adjust the total size written to keep the bytes written correct.
1458     writer()->adjust_bytes_written(-((long) sizeof(u4)));
1459 
1460     // seek to dump end so we can continue
1461     writer()->seek_to_offset(dump_end);
1462 
1463     // no current dump record
1464     set_dump_start((jlong)-1);
1465   }
1466 }
1467 
1468 // used on a sub-record boundary to check if we need to start a
1469 // new segment.
1470 void VM_HeapDumper::check_segment_length() {
1471   if (writer()->is_open()) {
1472     if (is_segmented_dump()) {
1473       // don't use current_offset that would be too expensive on a per record basis
1474       jlong dump_end = writer()->bytes_written() + writer()->bytes_unwritten();
1475       assert(dump_end == writer()->current_offset(), "checking");
1476       jlong dump_len = (dump_end - dump_start() - 4);
1477       assert(dump_len >= 0 && dump_len <= max_juint, "bad dump length");
1478 
1479       if (dump_len > (jlong)HeapDumpSegmentSize) {
1480         write_current_dump_record_length();
1481         write_dump_header();
1482       }
1483     }
1484   }
1485 }
1486 
1487 // fixes up the current dump record )and writes HPROF_HEAP_DUMP_END
1488 // record in the case of a segmented heap dump)
1489 void VM_HeapDumper::end_of_dump() {
1490   if (writer()->is_open()) {
1491     write_current_dump_record_length();
1492 
1493     // for segmented dump we write the end record
1494     if (is_segmented_dump()) {
1495       writer()->write_u1(HPROF_HEAP_DUMP_END);
1496       writer()->write_u4(0);
1497       writer()->write_u4(0);
1498     }
1499   }
1500 }
1501 
1502 // marks sub-record boundary
1503 void HeapObjectDumper::mark_end_of_record() {
1504   dumper()->check_segment_length();
1505 }
1506 
1507 // writes a HPROF_LOAD_CLASS record for the class (and each of its
1508 // array classes)
1509 void VM_HeapDumper::do_load_class(klassOop k) {
1510   static u4 class_serial_num = 0;
1511 
1512   // len of HPROF_LOAD_CLASS record
1513   u4 remaining = 2*oopSize + 2*sizeof(u4);
1514 
1515   // write a HPROF_LOAD_CLASS for the class and each array class
1516   do {
1517     DumperSupport::write_header(writer(), HPROF_LOAD_CLASS, remaining);
1518 
1519     // class serial number is just a number
1520     writer()->write_u4(++class_serial_num);
1521 
1522     // class ID
1523     Klass* klass = Klass::cast(k);
1524     writer()->write_classID(klass);
1525 
1526     // add the klassOop and class serial number pair
1527     dumper()->add_class_serial_number(klass, class_serial_num);
1528 
1529     writer()->write_u4(STACK_TRACE_ID);
1530 
1531     // class name ID
1532     symbolOop name = klass->name();
1533     writer()->write_objectID(name);
1534 
1535     // write a LOAD_CLASS record for the array type (if it exists)
1536     k = klass->array_klass_or_null();
1537   } while (k != NULL);
1538 }
1539 
1540 // writes a HPROF_GC_CLASS_DUMP record for the given class
1541 void VM_HeapDumper::do_class_dump(klassOop k) {
1542   DumperSupport::dump_class_and_array_classes(writer(), k);
1543 }
1544 
1545 // writes a HPROF_GC_CLASS_DUMP records for a given basic type
1546 // array (and each multi-dimensional array too)
1547 void VM_HeapDumper::do_basic_type_array_class_dump(klassOop k) {
1548   DumperSupport::dump_basic_type_array_class(writer(), k);
1549 }
1550 
1551 // Walk the stack of the given thread.
1552 // Dumps a HPROF_GC_ROOT_JAVA_FRAME record for each local
1553 // Dumps a HPROF_GC_ROOT_JNI_LOCAL record for each JNI local
1554 //
1555 // It returns the number of Java frames in this thread stack
1556 int VM_HeapDumper::do_thread(JavaThread* java_thread, u4 thread_serial_num) {
1557   JNILocalsDumper blk(writer(), thread_serial_num);
1558 
1559   oop threadObj = java_thread->threadObj();
1560   assert(threadObj != NULL, "sanity check");
1561 
1562   int stack_depth = 0;
1563   if (java_thread->has_last_Java_frame()) {
1564 
1565     // vframes are resource allocated
1566     Thread* current_thread = Thread::current();
1567     ResourceMark rm(current_thread);
1568     HandleMark hm(current_thread);
1569 
1570     RegisterMap reg_map(java_thread);
1571     frame f = java_thread->last_frame();
1572     vframe* vf = vframe::new_vframe(&f, &reg_map, java_thread);
1573     frame* last_entry_frame = NULL;
1574     int extra_frames = 0;
1575 
1576     if (java_thread == _oome_thread && _oome_constructor != NULL) {
1577       extra_frames++;
1578     }
1579     while (vf != NULL) {
1580       blk.set_frame_number(stack_depth);
1581       if (vf->is_java_frame()) {
1582 
1583         // java frame (interpreted, compiled, ...)
1584         javaVFrame *jvf = javaVFrame::cast(vf);
1585         if (!(jvf->method()->is_native())) {
1586           StackValueCollection* locals = jvf->locals();
1587           for (int slot=0; slot<locals->size(); slot++) {
1588             if (locals->at(slot)->type() == T_OBJECT) {
1589               oop o = locals->obj_at(slot)();
1590 
1591               if (o != NULL) {
1592                 writer()->write_u1(HPROF_GC_ROOT_JAVA_FRAME);
1593                 writer()->write_objectID(o);
1594                 writer()->write_u4(thread_serial_num);
1595                 writer()->write_u4((u4) (stack_depth + extra_frames));
1596               }
1597             }
1598           }
1599         } else {
1600           // native frame
1601           if (stack_depth == 0) {
1602             // JNI locals for the top frame.
1603             java_thread->active_handles()->oops_do(&blk);
1604           } else {
1605             if (last_entry_frame != NULL) {
1606               // JNI locals for the entry frame
1607               assert(last_entry_frame->is_entry_frame(), "checking");
1608               last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(&blk);
1609             }
1610           }
1611         }
1612         // increment only for Java frames
1613         stack_depth++;
1614         last_entry_frame = NULL;
1615 
1616       } else {
1617         // externalVFrame - if it's an entry frame then report any JNI locals
1618         // as roots when we find the corresponding native javaVFrame
1619         frame* fr = vf->frame_pointer();
1620         assert(fr != NULL, "sanity check");
1621         if (fr->is_entry_frame()) {
1622           last_entry_frame = fr;
1623         }
1624       }
1625       vf = vf->sender();
1626     }
1627   } else {
1628     // no last java frame but there may be JNI locals
1629     java_thread->active_handles()->oops_do(&blk);
1630   }
1631   return stack_depth;
1632 }
1633 
1634 
1635 // write a HPROF_GC_ROOT_THREAD_OBJ record for each java thread. Then walk
1636 // the stack so that locals and JNI locals are dumped.
1637 void VM_HeapDumper::do_threads() {
1638   for (int i=0; i < _num_threads; i++) {
1639     JavaThread* thread = _stack_traces[i]->thread();
1640     oop threadObj = thread->threadObj();
1641     u4 thread_serial_num = i+1;
1642     u4 stack_serial_num = thread_serial_num + STACK_TRACE_ID;
1643     writer()->write_u1(HPROF_GC_ROOT_THREAD_OBJ);
1644     writer()->write_objectID(threadObj);
1645     writer()->write_u4(thread_serial_num);  // thread number
1646     writer()->write_u4(stack_serial_num);   // stack trace serial number
1647     int num_frames = do_thread(thread, thread_serial_num);
1648     assert(num_frames == _stack_traces[i]->get_stack_depth(),
1649            "total number of Java frames not matched");
1650   }
1651 }
1652 
1653 
1654 // The VM operation that dumps the heap. The dump consists of the following
1655 // records:
1656 //
1657 //  HPROF_HEADER
1658 //  [HPROF_UTF8]*
1659 //  [HPROF_LOAD_CLASS]*
1660 //  [[HPROF_FRAME]*|HPROF_TRACE]*
1661 //  [HPROF_GC_CLASS_DUMP]*
1662 //  HPROF_HEAP_DUMP
1663 //
1664 // The HPROF_TRACE records represent the stack traces where the heap dump
1665 // is generated and a "dummy trace" record which does not include
1666 // any frames. The dummy trace record is used to be referenced as the
1667 // unknown object alloc site.
1668 //
1669 // The HPROF_HEAP_DUMP record has a length following by sub-records. To allow
1670 // the heap dump be generated in a single pass we remember the position of
1671 // the dump length and fix it up after all sub-records have been written.
1672 // To generate the sub-records we iterate over the heap, writing
1673 // HPROF_GC_INSTANCE_DUMP, HPROF_GC_OBJ_ARRAY_DUMP, and HPROF_GC_PRIM_ARRAY_DUMP
1674 // records as we go. Once that is done we write records for some of the GC
1675 // roots.
1676 
1677 void VM_HeapDumper::doit() {
1678 
1679   HandleMark hm;
1680   CollectedHeap* ch = Universe::heap();
1681   if (_gc_before_heap_dump) {
1682     ch->collect_as_vm_thread(GCCause::_heap_dump);
1683   } else {
1684     // make the heap parsable (no need to retire TLABs)
1685     ch->ensure_parsability(false);
1686   }
1687 
1688   // At this point we should be the only dumper active, so
1689   // the following should be safe.
1690   set_global_dumper();
1691   set_global_writer();
1692 
1693   // Write the file header - use 1.0.2 for large heaps, otherwise 1.0.1
1694   size_t used = ch->used();
1695   const char* header;
1696   if (used > (size_t)SegmentedHeapDumpThreshold) {
1697     set_segmented_dump();
1698     header = "JAVA PROFILE 1.0.2";
1699   } else {
1700     header = "JAVA PROFILE 1.0.1";
1701   }
1702 
1703   // header is few bytes long - no chance to overflow int
1704   writer()->write_raw((void*)header, (int)strlen(header));
1705   writer()->write_u1(0); // terminator
1706   writer()->write_u4(oopSize);
1707   writer()->write_u8(os::javaTimeMillis());
1708 
1709   // HPROF_UTF8 records
1710   SymbolTableDumper sym_dumper(writer());
1711   SymbolTable::oops_do(&sym_dumper);
1712 
1713   // write HPROF_LOAD_CLASS records
1714   SystemDictionary::classes_do(&do_load_class);
1715   Universe::basic_type_classes_do(&do_load_class);
1716 
1717   // write HPROF_FRAME and HPROF_TRACE records
1718   // this must be called after _klass_map is built when iterating the classes above.
1719   dump_stack_traces();
1720 
1721   // write HPROF_HEAP_DUMP or HPROF_HEAP_DUMP_SEGMENT
1722   write_dump_header();
1723 
1724   // Writes HPROF_GC_CLASS_DUMP records
1725   SystemDictionary::classes_do(&do_class_dump);
1726   Universe::basic_type_classes_do(&do_basic_type_array_class_dump);
1727   check_segment_length();
1728 
1729   // writes HPROF_GC_INSTANCE_DUMP records.
1730   // After each sub-record is written check_segment_length will be invoked. When
1731   // generated a segmented heap dump this allows us to check if the current
1732   // segment exceeds a threshold and if so, then a new segment is started.
1733   // The HPROF_GC_CLASS_DUMP and HPROF_GC_INSTANCE_DUMP are the vast bulk
1734   // of the heap dump.
1735   HeapObjectDumper obj_dumper(this, writer());
1736   Universe::heap()->safe_object_iterate(&obj_dumper);
1737 
1738   // HPROF_GC_ROOT_THREAD_OBJ + frames + jni locals
1739   do_threads();
1740   check_segment_length();
1741 
1742   // HPROF_GC_ROOT_MONITOR_USED
1743   MonitorUsedDumper mon_dumper(writer());
1744   ObjectSynchronizer::oops_do(&mon_dumper);
1745   check_segment_length();
1746 
1747   // HPROF_GC_ROOT_JNI_GLOBAL
1748   JNIGlobalsDumper jni_dumper(writer());
1749   JNIHandles::oops_do(&jni_dumper);
1750   check_segment_length();
1751 
1752   // HPROF_GC_ROOT_STICKY_CLASS
1753   StickyClassDumper class_dumper(writer());
1754   SystemDictionary::always_strong_oops_do(&class_dumper);
1755 
1756   // fixes up the length of the dump record. In the case of a segmented
1757   // heap then the HPROF_HEAP_DUMP_END record is also written.
1758   end_of_dump();
1759 
1760   // Now we clear the global variables, so that a future dumper might run.
1761   clear_global_dumper();
1762   clear_global_writer();
1763 }
1764 
1765 void VM_HeapDumper::dump_stack_traces() {
1766   // write a HPROF_TRACE record without any frames to be referenced as object alloc sites
1767   DumperSupport::write_header(writer(), HPROF_TRACE, 3*sizeof(u4));
1768   writer()->write_u4((u4) STACK_TRACE_ID);
1769   writer()->write_u4(0);                    // thread number
1770   writer()->write_u4(0);                    // frame count
1771 
1772   _stack_traces = NEW_C_HEAP_ARRAY(ThreadStackTrace*, Threads::number_of_threads());
1773   int frame_serial_num = 0;
1774   for (JavaThread* thread = Threads::first(); thread != NULL ; thread = thread->next()) {
1775     oop threadObj = thread->threadObj();
1776     if (threadObj != NULL && !thread->is_exiting() && !thread->is_hidden_from_external_view()) {
1777       // dump thread stack trace
1778       ThreadStackTrace* stack_trace = new ThreadStackTrace(thread, false);
1779       stack_trace->dump_stack_at_safepoint(-1);
1780       _stack_traces[_num_threads++] = stack_trace;
1781 
1782       // write HPROF_FRAME records for this thread's stack trace
1783       int depth = stack_trace->get_stack_depth();
1784       int thread_frame_start = frame_serial_num;
1785       int extra_frames = 0;
1786       // write fake frame that makes it look like the thread, which caused OOME,
1787       // is in the OutOfMemoryError zero-parameter constructor
1788       if (thread == _oome_thread && _oome_constructor != NULL) {
1789         int oome_serial_num = _klass_map->find(Klass::cast(_oome_constructor->method_holder()));
1790         // the class serial number starts from 1
1791         assert(oome_serial_num > 0, "OutOfMemoryError class not found");
1792         DumperSupport::dump_stack_frame(writer(), ++frame_serial_num, oome_serial_num,
1793                                         _oome_constructor, 0);
1794         extra_frames++;
1795       }
1796       for (int j=0; j < depth; j++) {
1797         StackFrameInfo* frame = stack_trace->stack_frame_at(j);
1798         methodOop m = frame->method();
1799         int class_serial_num = _klass_map->find(Klass::cast(m->method_holder()));
1800         // the class serial number starts from 1
1801         assert(class_serial_num > 0, "class not found");
1802         DumperSupport::dump_stack_frame(writer(), ++frame_serial_num, class_serial_num, m, frame->bci());
1803       }
1804       depth += extra_frames;
1805 
1806       // write HPROF_TRACE record for one thread
1807       DumperSupport::write_header(writer(), HPROF_TRACE, 3*sizeof(u4) + depth*oopSize);
1808       int stack_serial_num = _num_threads + STACK_TRACE_ID;
1809       writer()->write_u4(stack_serial_num);      // stack trace serial number
1810       writer()->write_u4((u4) _num_threads);     // thread serial number
1811       writer()->write_u4(depth);                 // frame count
1812       for (int j=1; j <= depth; j++) {
1813         writer()->write_id(thread_frame_start + j);
1814       }
1815     }
1816   }
1817 }
1818 
1819 // dump the heap to given path.
1820 int HeapDumper::dump(const char* path) {
1821   assert(path != NULL && strlen(path) > 0, "path missing");
1822 
1823   // print message in interactive case
1824   if (print_to_tty()) {
1825     tty->print_cr("Dumping heap to %s ...", path);
1826     timer()->start();
1827   }
1828 
1829   // create the dump writer. If the file can be opened then bail
1830   DumpWriter writer(path);
1831   if (!writer.is_open()) {
1832     set_error(writer.error());
1833     if (print_to_tty()) {
1834       tty->print_cr("Unable to create %s: %s", path,
1835         (error() != NULL) ? error() : "reason unknown");
1836     }
1837     return -1;
1838   }
1839 
1840   // generate the dump
1841   VM_HeapDumper dumper(&writer, _gc_before_heap_dump, _oome);
1842   if (Thread::current()->is_VM_thread()) {
1843     assert(SafepointSynchronize::is_at_safepoint(), "Expected to be called at a safepoint");
1844     dumper.doit();
1845   } else {
1846     VMThread::execute(&dumper);
1847   }
1848 
1849   // close dump file and record any error that the writer may have encountered
1850   writer.close();
1851   set_error(writer.error());
1852 
1853   // print message in interactive case
1854   if (print_to_tty()) {
1855     timer()->stop();
1856     if (error() == NULL) {
1857       char msg[256];
1858       sprintf(msg, "Heap dump file created [%s bytes in %3.3f secs]",
1859         os::jlong_format_specifier(), timer()->seconds());
1860       tty->print_cr(msg, writer.bytes_written());
1861     } else {
1862       tty->print_cr("Dump file is incomplete: %s", writer.error());
1863     }
1864   }
1865 
1866   return (writer.error() == NULL) ? 0 : -1;
1867 }
1868 
1869 // stop timer (if still active), and free any error string we might be holding
1870 HeapDumper::~HeapDumper() {
1871   if (timer()->is_active()) {
1872     timer()->stop();
1873   }
1874   set_error(NULL);
1875 }
1876 
1877 
1878 // returns the error string (resource allocated), or NULL
1879 char* HeapDumper::error_as_C_string() const {
1880   if (error() != NULL) {
1881     char* str = NEW_RESOURCE_ARRAY(char, strlen(error())+1);
1882     strcpy(str, error());
1883     return str;
1884   } else {
1885     return NULL;
1886   }
1887 }
1888 
1889 // set the error string
1890 void HeapDumper::set_error(char* error) {
1891   if (_error != NULL) {
1892     os::free(_error);
1893   }
1894   if (error == NULL) {
1895     _error = NULL;
1896   } else {
1897     _error = os::strdup(error);
1898     assert(_error != NULL, "allocation failure");
1899   }
1900 }
1901 
1902 // Called by out-of-memory error reporting by a single Java thread
1903 // outside of a JVM safepoint
1904 void HeapDumper::dump_heap_from_oome() {
1905   HeapDumper::dump_heap(true);
1906 }
1907 
1908 // Called by error reporting by a single Java thread outside of a JVM safepoint,
1909 // or by heap dumping by the VM thread during a (GC) safepoint. Thus, these various
1910 // callers are strictly serialized and guaranteed not to interfere below. For more
1911 // general use, however, this method will need modification to prevent
1912 // inteference when updating the static variables base_path and dump_file_seq below.
1913 void HeapDumper::dump_heap() {
1914   HeapDumper::dump_heap(false);
1915 }
1916 
1917 void HeapDumper::dump_heap(bool oome) {
1918   static char base_path[JVM_MAXPATHLEN] = {'\0'};
1919   static uint dump_file_seq = 0;
1920   char   my_path[JVM_MAXPATHLEN] = {'\0'};
1921 
1922   // The dump file defaults to java_pid<pid>.hprof in the current working
1923   // directory. HeapDumpPath=<file> can be used to specify an alternative
1924   // dump file name or a directory where dump file is created.
1925   if (dump_file_seq == 0) { // first time in, we initialize base_path
1926     bool use_default_filename = true;
1927     if (HeapDumpPath == NULL || HeapDumpPath[0] == '\0') {
1928       // HeapDumpPath=<file> not specified
1929     } else {
1930       assert(strlen(HeapDumpPath) < sizeof(base_path), "HeapDumpPath too long");
1931       strcpy(base_path, HeapDumpPath);
1932       // check if the path is a directory (must exist)
1933       DIR* dir = os::opendir(base_path);
1934       if (dir == NULL) {
1935         use_default_filename = false;
1936       } else {
1937         // HeapDumpPath specified a directory. We append a file separator
1938         // (if needed).
1939         os::closedir(dir);
1940         size_t fs_len = strlen(os::file_separator());
1941         if (strlen(base_path) >= fs_len) {
1942           char* end = base_path;
1943           end += (strlen(base_path) - fs_len);
1944           if (strcmp(end, os::file_separator()) != 0) {
1945             assert(strlen(base_path) + strlen(os::file_separator()) < sizeof(base_path),
1946               "HeapDumpPath too long");
1947             strcat(base_path, os::file_separator());
1948           }
1949         }
1950       }
1951     }
1952     // If HeapDumpPath wasn't a file name then we append the default name
1953     if (use_default_filename) {
1954       char fn[32];
1955       sprintf(fn, "java_pid%d", os::current_process_id());
1956       assert(strlen(base_path) + strlen(fn) + strlen(".hprof") < sizeof(base_path), "HeapDumpPath too long");
1957       strcat(base_path, fn);
1958       strcat(base_path, ".hprof");
1959     }
1960     assert(strlen(base_path) < sizeof(my_path), "Buffer too small");
1961     strcpy(my_path, base_path);
1962   } else {
1963     // Append a sequence number id for dumps following the first
1964     char fn[33];
1965     sprintf(fn, ".%d", dump_file_seq);
1966     assert(strlen(base_path) + strlen(fn) < sizeof(my_path), "HeapDumpPath too long");
1967     strcpy(my_path, base_path);
1968     strcat(my_path, fn);
1969   }
1970   dump_file_seq++;   // increment seq number for next time we dump
1971 
1972   HeapDumper dumper(false /* no GC before heap dump */,
1973                     true  /* send to tty */,
1974                     oome  /* pass along out-of-memory-error flag */);
1975   dumper.dump(my_path);
1976 }