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 "classfile/symbolTable.hpp"
  27 #include "classfile/systemDictionary.hpp"
  28 #include "classfile/vmSymbols.hpp"
  29 #include "gc_implementation/shared/vmGCOperations.hpp"
  30 #include "memory/gcLocker.inline.hpp"
  31 #include "memory/genCollectedHeap.hpp"
  32 #include "memory/universe.hpp"
  33 #include "oops/objArrayKlass.hpp"
  34 #include "runtime/javaCalls.hpp"
  35 #include "runtime/jniHandles.hpp"
  36 #include "runtime/reflectionUtils.hpp"
  37 #include "runtime/vframe.hpp"
  38 #include "runtime/vmThread.hpp"
  39 #include "runtime/vm_operations.hpp"
  40 #include "services/heapDumper.hpp"
  41 #include "services/threadService.hpp"
  42 #include "utilities/ostream.hpp"
  43 #include "utilities/macros.hpp"
  44 #if INCLUDE_ALL_GCS
  45 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
  46 #endif // INCLUDE_ALL_GCS
  47 
  48 /*
  49  * HPROF binary format - description copied from:
  50  *   src/share/demo/jvmti/hprof/hprof_io.c
  51  *
  52  *
  53  *  header    "JAVA PROFILE 1.0.1" or "JAVA PROFILE 1.0.2"
  54  *            (0-terminated)
  55  *
  56  *  u4        size of identifiers. Identifiers are used to represent
  57  *            UTF8 strings, objects, stack traces, etc. They usually
  58  *            have the same size as host pointers. For example, on
  59  *            Solaris and Win32, the size is 4.
  60  * u4         high word
  61  * u4         low word    number of milliseconds since 0:00 GMT, 1/1/70
  62  * [record]*  a sequence of records.
  63  *
  64  *
  65  * Record format:
  66  *
  67  * u1         a TAG denoting the type of the record
  68  * u4         number of *microseconds* since the time stamp in the
  69  *            header. (wraps around in a little more than an hour)
  70  * u4         number of bytes *remaining* in the record. Note that
  71  *            this number excludes the tag and the length field itself.
  72  * [u1]*      BODY of the record (a sequence of bytes)
  73  *
  74  *
  75  * The following TAGs are supported:
  76  *
  77  * TAG           BODY       notes
  78  *----------------------------------------------------------
  79  * HPROF_UTF8               a UTF8-encoded name
  80  *
  81  *               id         name ID
  82  *               [u1]*      UTF8 characters (no trailing zero)
  83  *
  84  * HPROF_LOAD_CLASS         a newly loaded class
  85  *
  86  *                u4        class serial number (> 0)
  87  *                id        class object ID
  88  *                u4        stack trace serial number
  89  *                id        class name ID
  90  *
  91  * HPROF_UNLOAD_CLASS       an unloading class
  92  *
  93  *                u4        class serial_number
  94  *
  95  * HPROF_FRAME              a Java stack frame
  96  *
  97  *                id        stack frame ID
  98  *                id        method name ID
  99  *                id        method signature ID
 100  *                id        source file name ID
 101  *                u4        class serial number
 102  *                i4        line number. >0: normal
 103  *                                       -1: unknown
 104  *                                       -2: compiled method
 105  *                                       -3: native method
 106  *
 107  * HPROF_TRACE              a Java stack trace
 108  *
 109  *               u4         stack trace serial number
 110  *               u4         thread serial number
 111  *               u4         number of frames
 112  *               [id]*      stack frame IDs
 113  *
 114  *
 115  * HPROF_ALLOC_SITES        a set of heap allocation sites, obtained after GC
 116  *
 117  *               u2         flags 0x0001: incremental vs. complete
 118  *                                0x0002: sorted by allocation vs. live
 119  *                                0x0004: whether to force a GC
 120  *               u4         cutoff ratio
 121  *               u4         total live bytes
 122  *               u4         total live instances
 123  *               u8         total bytes allocated
 124  *               u8         total instances allocated
 125  *               u4         number of sites that follow
 126  *               [u1        is_array: 0:  normal object
 127  *                                    2:  object array
 128  *                                    4:  boolean array
 129  *                                    5:  char array
 130  *                                    6:  float array
 131  *                                    7:  double array
 132  *                                    8:  byte array
 133  *                                    9:  short array
 134  *                                    10: int array
 135  *                                    11: long array
 136  *                u4        class serial number (may be zero during startup)
 137  *                u4        stack trace serial number
 138  *                u4        number of bytes alive
 139  *                u4        number of instances alive
 140  *                u4        number of bytes allocated
 141  *                u4]*      number of instance allocated
 142  *
 143  * HPROF_START_THREAD       a newly started thread.
 144  *
 145  *               u4         thread serial number (> 0)
 146  *               id         thread object ID
 147  *               u4         stack trace serial number
 148  *               id         thread name ID
 149  *               id         thread group name ID
 150  *               id         thread group parent name ID
 151  *
 152  * HPROF_END_THREAD         a terminating thread.
 153  *
 154  *               u4         thread serial number
 155  *
 156  * HPROF_HEAP_SUMMARY       heap summary
 157  *
 158  *               u4         total live bytes
 159  *               u4         total live instances
 160  *               u8         total bytes allocated
 161  *               u8         total instances allocated
 162  *
 163  * HPROF_HEAP_DUMP          denote a heap dump
 164  *
 165  *               [heap dump sub-records]*
 166  *
 167  *                          There are four kinds of heap dump sub-records:
 168  *
 169  *               u1         sub-record type
 170  *
 171  *               HPROF_GC_ROOT_UNKNOWN         unknown root
 172  *
 173  *                          id         object ID
 174  *
 175  *               HPROF_GC_ROOT_THREAD_OBJ      thread object
 176  *
 177  *                          id         thread object ID  (may be 0 for a
 178  *                                     thread newly attached through JNI)
 179  *                          u4         thread sequence number
 180  *                          u4         stack trace sequence number
 181  *
 182  *               HPROF_GC_ROOT_JNI_GLOBAL      JNI global ref root
 183  *
 184  *                          id         object ID
 185  *                          id         JNI global ref ID
 186  *
 187  *               HPROF_GC_ROOT_JNI_LOCAL       JNI local ref
 188  *
 189  *                          id         object ID
 190  *                          u4         thread serial number
 191  *                          u4         frame # in stack trace (-1 for empty)
 192  *
 193  *               HPROF_GC_ROOT_JAVA_FRAME      Java stack frame
 194  *
 195  *                          id         object ID
 196  *                          u4         thread serial number
 197  *                          u4         frame # in stack trace (-1 for empty)
 198  *
 199  *               HPROF_GC_ROOT_NATIVE_STACK    Native stack
 200  *
 201  *                          id         object ID
 202  *                          u4         thread serial number
 203  *
 204  *               HPROF_GC_ROOT_STICKY_CLASS    System class
 205  *
 206  *                          id         object ID
 207  *
 208  *               HPROF_GC_ROOT_THREAD_BLOCK    Reference from thread block
 209  *
 210  *                          id         object ID
 211  *                          u4         thread serial number
 212  *
 213  *               HPROF_GC_ROOT_MONITOR_USED    Busy monitor
 214  *
 215  *                          id         object ID
 216  *
 217  *               HPROF_GC_CLASS_DUMP           dump of a class object
 218  *
 219  *                          id         class object ID
 220  *                          u4         stack trace serial number
 221  *                          id         super class object ID
 222  *                          id         class loader object ID
 223  *                          id         signers object ID
 224  *                          id         protection domain object ID
 225  *                          id         reserved
 226  *                          id         reserved
 227  *
 228  *                          u4         instance size (in bytes)
 229  *
 230  *                          u2         size of constant pool
 231  *                          [u2,       constant pool index,
 232  *                           ty,       type
 233  *                                     2:  object
 234  *                                     4:  boolean
 235  *                                     5:  char
 236  *                                     6:  float
 237  *                                     7:  double
 238  *                                     8:  byte
 239  *                                     9:  short
 240  *                                     10: int
 241  *                                     11: long
 242  *                           vl]*      and value
 243  *
 244  *                          u2         number of static fields
 245  *                          [id,       static field name,
 246  *                           ty,       type,
 247  *                           vl]*      and value
 248  *
 249  *                          u2         number of inst. fields (not inc. super)
 250  *                          [id,       instance field name,
 251  *                           ty]*      type
 252  *
 253  *               HPROF_GC_INSTANCE_DUMP        dump of a normal object
 254  *
 255  *                          id         object ID
 256  *                          u4         stack trace serial number
 257  *                          id         class object ID
 258  *                          u4         number of bytes that follow
 259  *                          [vl]*      instance field values (class, followed
 260  *                                     by super, super's super ...)
 261  *
 262  *               HPROF_GC_OBJ_ARRAY_DUMP       dump of an object array
 263  *
 264  *                          id         array object ID
 265  *                          u4         stack trace serial number
 266  *                          u4         number of elements
 267  *                          id         array class ID
 268  *                          [id]*      elements
 269  *
 270  *               HPROF_GC_PRIM_ARRAY_DUMP      dump of a primitive array
 271  *
 272  *                          id         array object ID
 273  *                          u4         stack trace serial number
 274  *                          u4         number of elements
 275  *                          u1         element type
 276  *                                     4:  boolean array
 277  *                                     5:  char array
 278  *                                     6:  float array
 279  *                                     7:  double array
 280  *                                     8:  byte array
 281  *                                     9:  short array
 282  *                                     10: int array
 283  *                                     11: long array
 284  *                          [u1]*      elements
 285  *
 286  * HPROF_CPU_SAMPLES        a set of sample traces of running threads
 287  *
 288  *                u4        total number of samples
 289  *                u4        # of traces
 290  *               [u4        # of samples
 291  *                u4]*      stack trace serial number
 292  *
 293  * HPROF_CONTROL_SETTINGS   the settings of on/off switches
 294  *
 295  *                u4        0x00000001: alloc traces on/off
 296  *                          0x00000002: cpu sampling on/off
 297  *                u2        stack trace depth
 298  *
 299  *
 300  * When the header is "JAVA PROFILE 1.0.2" a heap dump can optionally
 301  * be generated as a sequence of heap dump segments. This sequence is
 302  * terminated by an end record. The additional tags allowed by format
 303  * "JAVA PROFILE 1.0.2" are:
 304  *
 305  * HPROF_HEAP_DUMP_SEGMENT  denote a heap dump segment
 306  *
 307  *               [heap dump sub-records]*
 308  *               The same sub-record types allowed by HPROF_HEAP_DUMP
 309  *
 310  * HPROF_HEAP_DUMP_END      denotes the end of a heap dump
 311  *
 312  */
 313 
 314 
 315 // HPROF tags
 316 
 317 typedef enum {
 318   // top-level records
 319   HPROF_UTF8                    = 0x01,
 320   HPROF_LOAD_CLASS              = 0x02,
 321   HPROF_UNLOAD_CLASS            = 0x03,
 322   HPROF_FRAME                   = 0x04,
 323   HPROF_TRACE                   = 0x05,
 324   HPROF_ALLOC_SITES             = 0x06,
 325   HPROF_HEAP_SUMMARY            = 0x07,
 326   HPROF_START_THREAD            = 0x0A,
 327   HPROF_END_THREAD              = 0x0B,
 328   HPROF_HEAP_DUMP               = 0x0C,
 329   HPROF_CPU_SAMPLES             = 0x0D,
 330   HPROF_CONTROL_SETTINGS        = 0x0E,
 331 
 332   // 1.0.2 record types
 333   HPROF_HEAP_DUMP_SEGMENT       = 0x1C,
 334   HPROF_HEAP_DUMP_END           = 0x2C,
 335 
 336   // field types
 337   HPROF_ARRAY_OBJECT            = 0x01,
 338   HPROF_NORMAL_OBJECT           = 0x02,
 339   HPROF_BOOLEAN                 = 0x04,
 340   HPROF_CHAR                    = 0x05,
 341   HPROF_FLOAT                   = 0x06,
 342   HPROF_DOUBLE                  = 0x07,
 343   HPROF_BYTE                    = 0x08,
 344   HPROF_SHORT                   = 0x09,
 345   HPROF_INT                     = 0x0A,
 346   HPROF_LONG                    = 0x0B,
 347 
 348   // data-dump sub-records
 349   HPROF_GC_ROOT_UNKNOWN         = 0xFF,
 350   HPROF_GC_ROOT_JNI_GLOBAL      = 0x01,
 351   HPROF_GC_ROOT_JNI_LOCAL       = 0x02,
 352   HPROF_GC_ROOT_JAVA_FRAME      = 0x03,
 353   HPROF_GC_ROOT_NATIVE_STACK    = 0x04,
 354   HPROF_GC_ROOT_STICKY_CLASS    = 0x05,
 355   HPROF_GC_ROOT_THREAD_BLOCK    = 0x06,
 356   HPROF_GC_ROOT_MONITOR_USED    = 0x07,
 357   HPROF_GC_ROOT_THREAD_OBJ      = 0x08,
 358   HPROF_GC_CLASS_DUMP           = 0x20,
 359   HPROF_GC_INSTANCE_DUMP        = 0x21,
 360   HPROF_GC_OBJ_ARRAY_DUMP       = 0x22,
 361   HPROF_GC_PRIM_ARRAY_DUMP      = 0x23
 362 } hprofTag;
 363 
 364 // Default stack trace ID (used for dummy HPROF_TRACE record)
 365 enum {
 366   STACK_TRACE_ID = 1,
 367   INITIAL_CLASS_COUNT = 200
 368 };
 369 
 370 // Supports I/O operations on a dump file
 371 
 372 class DumpWriter : public StackObj {
 373  private:
 374   enum {
 375     io_buffer_size  = 8*M
 376   };
 377 
 378   int _fd;              // file descriptor (-1 if dump file not open)
 379   julong _bytes_written; // number of byte written to dump file
 380 
 381   char* _buffer;    // internal buffer
 382   size_t _size;
 383   size_t _pos;
 384 
 385   char* _error;   // error message when I/O fails
 386 
 387   void set_file_descriptor(int fd)              { _fd = fd; }
 388   int file_descriptor() const                   { return _fd; }
 389 
 390   char* buffer() const                          { return _buffer; }
 391   size_t buffer_size() const                    { return _size; }
 392   size_t position() const                       { return _pos; }
 393   void set_position(size_t pos)                 { _pos = pos; }
 394 
 395   void set_error(const char* error)             { _error = (char*)os::strdup(error); }
 396 
 397   // all I/O go through this function
 398   void write_internal(void* s, size_t len);
 399 
 400  public:
 401   DumpWriter(const char* path);
 402   ~DumpWriter();
 403 
 404   void close();
 405   bool is_open() const                  { return file_descriptor() >= 0; }
 406   void flush();
 407 
 408   // total number of bytes written to the disk
 409   julong bytes_written() const          { return _bytes_written; }
 410 
 411   // adjust the number of bytes written to disk (used to keep the count
 412   // of the number of bytes written in case of rewrites)
 413   void adjust_bytes_written(jlong n)    { _bytes_written += n; }
 414 
 415   // number of (buffered) bytes as yet unwritten to the dump file
 416   size_t bytes_unwritten() const        { return position(); }
 417 
 418   char* error() const                   { return _error; }
 419 
 420   jlong current_offset();
 421   void seek_to_offset(jlong pos);
 422 
 423   // writer functions
 424   void write_raw(void* s, size_t len);
 425   void write_u1(u1 x)                   { write_raw((void*)&x, 1); }
 426   void write_u2(u2 x);
 427   void write_u4(u4 x);
 428   void write_u8(u8 x);
 429   void write_objectID(oop o);
 430   void write_symbolID(Symbol* o);
 431   void write_classID(Klass* k);
 432   void write_id(u4 x);
 433 };
 434 
 435 DumpWriter::DumpWriter(const char* path) {
 436   // try to allocate an I/O buffer of io_buffer_size. If there isn't
 437   // sufficient memory then reduce size until we can allocate something.
 438   _size = io_buffer_size;
 439   do {
 440     _buffer = (char*)os::malloc(_size, mtInternal);
 441     if (_buffer == NULL) {
 442       _size = _size >> 1;
 443     }
 444   } while (_buffer == NULL && _size > 0);
 445   assert((_size > 0 && _buffer != NULL) || (_size == 0 && _buffer == NULL), "sanity check");
 446   _pos = 0;
 447   _error = NULL;
 448   _bytes_written = 0L;
 449   _fd = os::create_binary_file(path, false);    // don't replace existing file
 450 
 451   // if the open failed we record the error
 452   if (_fd < 0) {
 453     _error = (char*)os::strdup(strerror(errno));
 454   }
 455 }
 456 
 457 DumpWriter::~DumpWriter() {
 458   // flush and close dump file
 459   if (is_open()) {
 460     close();
 461   }
 462   if (_buffer != NULL) os::free(_buffer);
 463   if (_error != NULL) os::free(_error);
 464 }
 465 
 466 // closes dump file (if open)
 467 void DumpWriter::close() {
 468   // flush and close dump file
 469   if (is_open()) {
 470     flush();
 471     ::close(file_descriptor());
 472     set_file_descriptor(-1);
 473   }
 474 }
 475 
 476 // write directly to the file
 477 void DumpWriter::write_internal(void* s, size_t len) {
 478   if (is_open()) {
 479     const char* pos = (char*)s;
 480     ssize_t n = 0;
 481     while (len > 0) {
 482       uint tmp = (uint)MIN2(len, (size_t)UINT_MAX);
 483       n = ::write(file_descriptor(), pos, tmp);
 484 
 485       if (n < 0) {
 486         set_error(strerror(errno));
 487         ::close(file_descriptor());
 488         set_file_descriptor(-1);
 489         return;
 490       }
 491 
 492       _bytes_written += n;
 493       pos += n;
 494       len -= n;
 495     }
 496   }
 497 }
 498 
 499 // write raw bytes
 500 void DumpWriter::write_raw(void* s, size_t len) {
 501   if (is_open()) {
 502     // flush buffer to make room
 503     if ((position() + len) >= buffer_size()) {
 504       flush();
 505     }
 506 
 507     // buffer not available or too big to buffer it
 508     if ((buffer() == NULL) || (len >= buffer_size())) {
 509       write_internal(s, len);
 510     } else {
 511       // Should optimize this for u1/u2/u4/u8 sizes.
 512       memcpy(buffer() + position(), s, len);
 513       set_position(position() + len);
 514     }
 515   }
 516 }
 517 
 518 // flush any buffered bytes to the file
 519 void DumpWriter::flush() {
 520   if (is_open() && position() > 0) {
 521     write_internal(buffer(), position());
 522     set_position(0);
 523   }
 524 }
 525 
 526 jlong DumpWriter::current_offset() {
 527   if (is_open()) {
 528     // the offset is the file offset plus whatever we have buffered
 529     jlong offset = os::current_file_offset(file_descriptor());
 530     assert(offset >= 0, "lseek failed");
 531     return offset + position();
 532   } else {
 533     return (jlong)-1;
 534   }
 535 }
 536 
 537 void DumpWriter::seek_to_offset(jlong off) {
 538   assert(off >= 0, "bad offset");
 539 
 540   // need to flush before seeking
 541   flush();
 542 
 543   // may be closed due to I/O error
 544   if (is_open()) {
 545     jlong n = os::seek_to_file_offset(file_descriptor(), off);
 546     assert(n >= 0, "lseek failed");
 547   }
 548 }
 549 
 550 void DumpWriter::write_u2(u2 x) {
 551   u2 v;
 552   Bytes::put_Java_u2((address)&v, x);
 553   write_raw((void*)&v, 2);
 554 }
 555 
 556 void DumpWriter::write_u4(u4 x) {
 557   u4 v;
 558   Bytes::put_Java_u4((address)&v, x);
 559   write_raw((void*)&v, 4);
 560 }
 561 
 562 void DumpWriter::write_u8(u8 x) {
 563   u8 v;
 564   Bytes::put_Java_u8((address)&v, x);
 565   write_raw((void*)&v, 8);
 566 }
 567 
 568 void DumpWriter::write_objectID(oop o) {
 569   address a = (address)o;
 570 #ifdef _LP64
 571   write_u8((u8)a);
 572 #else
 573   write_u4((u4)a);
 574 #endif
 575 }
 576 
 577 void DumpWriter::write_symbolID(Symbol* s) {
 578   address a = (address)((uintptr_t)s);
 579 #ifdef _LP64
 580   write_u8((u8)a);
 581 #else
 582   write_u4((u4)a);
 583 #endif
 584 }
 585 
 586 void DumpWriter::write_id(u4 x) {
 587 #ifdef _LP64
 588   write_u8((u8) x);
 589 #else
 590   write_u4(x);
 591 #endif
 592 }
 593 
 594 // We use java mirror as the class ID
 595 void DumpWriter::write_classID(Klass* k) {
 596   write_objectID(k->java_mirror());
 597 }
 598 
 599 
 600 
 601 // Support class with a collection of functions used when dumping the heap
 602 
 603 class DumperSupport : AllStatic {
 604  public:
 605 
 606   // write a header of the given type
 607   static void write_header(DumpWriter* writer, hprofTag tag, u4 len);
 608 
 609   // returns hprof tag for the given type signature
 610   static hprofTag sig2tag(Symbol* sig);
 611   // returns hprof tag for the given basic type
 612   static hprofTag type2tag(BasicType type);
 613 
 614   // returns the size of the instance of the given class
 615   static u4 instance_size(Klass* k);
 616 
 617   // dump a jfloat
 618   static void dump_float(DumpWriter* writer, jfloat f);
 619   // dump a jdouble
 620   static void dump_double(DumpWriter* writer, jdouble d);
 621   // dumps the raw value of the given field
 622   static void dump_field_value(DumpWriter* writer, char type, address addr);
 623   // dumps static fields of the given class
 624   static void dump_static_fields(DumpWriter* writer, Klass* k);
 625   // dump the raw values of the instance fields of the given object
 626   static void dump_instance_fields(DumpWriter* writer, oop o);
 627   // dumps the definition of the instance fields for a given class
 628   static void dump_instance_field_descriptors(DumpWriter* writer, Klass* k);
 629   // creates HPROF_GC_INSTANCE_DUMP record for the given object
 630   static void dump_instance(DumpWriter* writer, oop o);
 631   // creates HPROF_GC_CLASS_DUMP record for the given class and each of its
 632   // array classes
 633   static void dump_class_and_array_classes(DumpWriter* writer, Klass* k);
 634   // creates HPROF_GC_CLASS_DUMP record for a given primitive array
 635   // class (and each multi-dimensional array class too)
 636   static void dump_basic_type_array_class(DumpWriter* writer, Klass* k);
 637 
 638   // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
 639   static void dump_object_array(DumpWriter* writer, objArrayOop array);
 640   // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
 641   static void dump_prim_array(DumpWriter* writer, typeArrayOop array);
 642   // create HPROF_FRAME record for the given method and bci
 643   static void dump_stack_frame(DumpWriter* writer, int frame_serial_num, int class_serial_num, Method* m, int bci);
 644 };
 645 
 646 // write a header of the given type
 647 void DumperSupport:: write_header(DumpWriter* writer, hprofTag tag, u4 len) {
 648   writer->write_u1((u1)tag);
 649   writer->write_u4(0);                  // current ticks
 650   writer->write_u4(len);
 651 }
 652 
 653 // returns hprof tag for the given type signature
 654 hprofTag DumperSupport::sig2tag(Symbol* sig) {
 655   switch (sig->byte_at(0)) {
 656     case JVM_SIGNATURE_CLASS    : return HPROF_NORMAL_OBJECT;
 657     case JVM_SIGNATURE_ARRAY    : return HPROF_NORMAL_OBJECT;
 658     case JVM_SIGNATURE_BYTE     : return HPROF_BYTE;
 659     case JVM_SIGNATURE_CHAR     : return HPROF_CHAR;
 660     case JVM_SIGNATURE_FLOAT    : return HPROF_FLOAT;
 661     case JVM_SIGNATURE_DOUBLE   : return HPROF_DOUBLE;
 662     case JVM_SIGNATURE_INT      : return HPROF_INT;
 663     case JVM_SIGNATURE_LONG     : return HPROF_LONG;
 664     case JVM_SIGNATURE_SHORT    : return HPROF_SHORT;
 665     case JVM_SIGNATURE_BOOLEAN  : return HPROF_BOOLEAN;
 666     default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
 667   }
 668 }
 669 
 670 hprofTag DumperSupport::type2tag(BasicType type) {
 671   switch (type) {
 672     case T_BYTE     : return HPROF_BYTE;
 673     case T_CHAR     : return HPROF_CHAR;
 674     case T_FLOAT    : return HPROF_FLOAT;
 675     case T_DOUBLE   : return HPROF_DOUBLE;
 676     case T_INT      : return HPROF_INT;
 677     case T_LONG     : return HPROF_LONG;
 678     case T_SHORT    : return HPROF_SHORT;
 679     case T_BOOLEAN  : return HPROF_BOOLEAN;
 680     default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
 681   }
 682 }
 683 
 684 // dump a jfloat
 685 void DumperSupport::dump_float(DumpWriter* writer, jfloat f) {
 686   if (g_isnan(f)) {
 687     writer->write_u4(0x7fc00000);    // collapsing NaNs
 688   } else {
 689     union {
 690       int i;
 691       float f;
 692     } u;
 693     u.f = (float)f;
 694     writer->write_u4((u4)u.i);
 695   }
 696 }
 697 
 698 // dump a jdouble
 699 void DumperSupport::dump_double(DumpWriter* writer, jdouble d) {
 700   union {
 701     jlong l;
 702     double d;
 703   } u;
 704   if (g_isnan(d)) {                 // collapsing NaNs
 705     u.l = (jlong)(0x7ff80000);
 706     u.l = (u.l << 32);
 707   } else {
 708     u.d = (double)d;
 709   }
 710   writer->write_u8((u8)u.l);
 711 }
 712 
 713 // dumps the raw value of the given field
 714 void DumperSupport::dump_field_value(DumpWriter* writer, char type, address addr) {
 715   switch (type) {
 716     case JVM_SIGNATURE_CLASS :
 717     case JVM_SIGNATURE_ARRAY : {
 718       oop o;
 719       if (UseCompressedOops) {
 720         o = oopDesc::load_decode_heap_oop((narrowOop*)addr);
 721       } else {
 722         o = oopDesc::load_decode_heap_oop((oop*)addr);
 723       }
 724 
 725       // reflection and sun.misc.Unsafe classes may have a reference to a
 726       // Klass* so filter it out.
 727       assert(o->is_oop_or_null(), "should always be an oop");
 728       writer->write_objectID(o);
 729       break;
 730     }
 731     case JVM_SIGNATURE_BYTE     : {
 732       jbyte* b = (jbyte*)addr;
 733       writer->write_u1((u1)*b);
 734       break;
 735     }
 736     case JVM_SIGNATURE_CHAR     : {
 737       jchar* c = (jchar*)addr;
 738       writer->write_u2((u2)*c);
 739       break;
 740     }
 741     case JVM_SIGNATURE_SHORT : {
 742       jshort* s = (jshort*)addr;
 743       writer->write_u2((u2)*s);
 744       break;
 745     }
 746     case JVM_SIGNATURE_FLOAT : {
 747       jfloat* f = (jfloat*)addr;
 748       dump_float(writer, *f);
 749       break;
 750     }
 751     case JVM_SIGNATURE_DOUBLE : {
 752       jdouble* f = (jdouble*)addr;
 753       dump_double(writer, *f);
 754       break;
 755     }
 756     case JVM_SIGNATURE_INT : {
 757       jint* i = (jint*)addr;
 758       writer->write_u4((u4)*i);
 759       break;
 760     }
 761     case JVM_SIGNATURE_LONG     : {
 762       jlong* l = (jlong*)addr;
 763       writer->write_u8((u8)*l);
 764       break;
 765     }
 766     case JVM_SIGNATURE_BOOLEAN : {
 767       jboolean* b = (jboolean*)addr;
 768       writer->write_u1((u1)*b);
 769       break;
 770     }
 771     default : ShouldNotReachHere();
 772   }
 773 }
 774 
 775 // returns the size of the instance of the given class
 776 u4 DumperSupport::instance_size(Klass* k) {
 777   HandleMark hm;
 778   instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), k);
 779 
 780   u4 size = 0;
 781 
 782   for (FieldStream fld(ikh, false, false); !fld.eos(); fld.next()) {
 783     if (!fld.access_flags().is_static()) {
 784       Symbol* sig = fld.signature();
 785       switch (sig->byte_at(0)) {
 786         case JVM_SIGNATURE_CLASS   :
 787         case JVM_SIGNATURE_ARRAY   : size += oopSize; break;
 788 
 789         case JVM_SIGNATURE_BYTE    :
 790         case JVM_SIGNATURE_BOOLEAN : size += 1; break;
 791 
 792         case JVM_SIGNATURE_CHAR    :
 793         case JVM_SIGNATURE_SHORT   : size += 2; break;
 794 
 795         case JVM_SIGNATURE_INT     :
 796         case JVM_SIGNATURE_FLOAT   : size += 4; break;
 797 
 798         case JVM_SIGNATURE_LONG    :
 799         case JVM_SIGNATURE_DOUBLE  : size += 8; break;
 800 
 801         default : ShouldNotReachHere();
 802       }
 803     }
 804   }
 805   return size;
 806 }
 807 
 808 // dumps static fields of the given class
 809 void DumperSupport::dump_static_fields(DumpWriter* writer, Klass* k) {
 810   HandleMark hm;
 811   instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), k);
 812 
 813   // pass 1 - count the static fields
 814   u2 field_count = 0;
 815   for (FieldStream fldc(ikh, true, true); !fldc.eos(); fldc.next()) {
 816     if (fldc.access_flags().is_static()) field_count++;
 817   }
 818   // Add in resolved_references which is referenced by the cpCache
 819   // The resolved_references is an array per InstanceKlass holding the
 820   // strings and other oops resolved from the constant pool.
 821   oop resolved_references = ikh->constants()->resolved_references_or_null();
 822   if (resolved_references != NULL) {
 823     field_count++;
 824 
 825     // Add in the resolved_references of the used previous versions of the class
 826     // in the case of RedefineClasses
 827     InstanceKlass* prev = ikh->previous_versions();
 828     while (prev != NULL && prev->constants()->resolved_references_or_null() != NULL) {
 829       field_count++;
 830       prev = prev->previous_versions();
 831     }
 832   }
 833 
 834   // Also provide a pointer to the init_lock if present, so there aren't unreferenced int[0]
 835   // arrays.
 836   oop init_lock = ikh->init_lock();
 837   if (init_lock != NULL) {
 838     field_count++;
 839   }
 840 
 841   writer->write_u2(field_count);
 842 
 843   // pass 2 - dump the field descriptors and raw values
 844   for (FieldStream fld(ikh, true, true); !fld.eos(); fld.next()) {
 845     if (fld.access_flags().is_static()) {
 846       Symbol* sig = fld.signature();
 847 
 848       writer->write_symbolID(fld.name());   // name
 849       writer->write_u1(sig2tag(sig));       // type
 850 
 851       // value
 852       int offset = fld.offset();
 853       address addr = (address)ikh->java_mirror() + offset;
 854 
 855       dump_field_value(writer, sig->byte_at(0), addr);
 856     }
 857   }
 858 
 859   // Add resolved_references for each class that has them
 860   if (resolved_references != NULL) {
 861     writer->write_symbolID(vmSymbols::resolved_references_name());  // name
 862     writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
 863     writer->write_objectID(resolved_references);
 864 
 865     // Also write any previous versions
 866     InstanceKlass* prev = ikh->previous_versions();
 867     while (prev != NULL && prev->constants()->resolved_references_or_null() != NULL) {
 868       writer->write_symbolID(vmSymbols::resolved_references_name());  // name
 869       writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
 870       writer->write_objectID(prev->constants()->resolved_references());
 871       prev = prev->previous_versions();
 872     }
 873   }
 874 
 875   // Add init lock to the end if the class is not yet initialized
 876   if (init_lock != NULL) {
 877     writer->write_symbolID(vmSymbols::init_lock_name());         // name
 878     writer->write_u1(sig2tag(vmSymbols::int_array_signature())); // type
 879     writer->write_objectID(init_lock);
 880   }
 881 }
 882 
 883 // dump the raw values of the instance fields of the given object
 884 void DumperSupport::dump_instance_fields(DumpWriter* writer, oop o) {
 885   HandleMark hm;
 886   instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), o->klass());
 887 
 888   for (FieldStream fld(ikh, false, false); !fld.eos(); fld.next()) {
 889     if (!fld.access_flags().is_static()) {
 890       Symbol* sig = fld.signature();
 891       address addr = (address)o + fld.offset();
 892 
 893       dump_field_value(writer, sig->byte_at(0), addr);
 894     }
 895   }
 896 }
 897 
 898 // dumps the definition of the instance fields for a given class
 899 void DumperSupport::dump_instance_field_descriptors(DumpWriter* writer, Klass* k) {
 900   HandleMark hm;
 901   instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), k);
 902 
 903   // pass 1 - count the instance fields
 904   u2 field_count = 0;
 905   for (FieldStream fldc(ikh, true, true); !fldc.eos(); fldc.next()) {
 906     if (!fldc.access_flags().is_static()) field_count++;
 907   }
 908 
 909   writer->write_u2(field_count);
 910 
 911   // pass 2 - dump the field descriptors
 912   for (FieldStream fld(ikh, true, true); !fld.eos(); fld.next()) {
 913     if (!fld.access_flags().is_static()) {
 914       Symbol* sig = fld.signature();
 915 
 916       writer->write_symbolID(fld.name());   // name
 917       writer->write_u1(sig2tag(sig));       // type
 918     }
 919   }
 920 }
 921 
 922 // creates HPROF_GC_INSTANCE_DUMP record for the given object
 923 void DumperSupport::dump_instance(DumpWriter* writer, oop o) {
 924   Klass* k = o->klass();
 925 
 926   writer->write_u1(HPROF_GC_INSTANCE_DUMP);
 927   writer->write_objectID(o);
 928   writer->write_u4(STACK_TRACE_ID);
 929 
 930   // class ID
 931   writer->write_classID(k);
 932 
 933   // number of bytes that follow
 934   writer->write_u4(instance_size(k) );
 935 
 936   // field values
 937   dump_instance_fields(writer, o);
 938 }
 939 
 940 // creates HPROF_GC_CLASS_DUMP record for the given class and each of
 941 // its array classes
 942 void DumperSupport::dump_class_and_array_classes(DumpWriter* writer, Klass* k) {
 943   Klass* klass = k;
 944   InstanceKlass* ik = InstanceKlass::cast(k);
 945 
 946   // We can safepoint and do a heap dump at a point where we have a Klass,
 947   // but no java mirror class has been setup for it. So we need to check
 948   // that the class is at least loaded, to avoid crash from a null mirror.
 949   if (!ik->is_loaded()) {
 950     return;
 951   }
 952 
 953   writer->write_u1(HPROF_GC_CLASS_DUMP);
 954 
 955   // class ID
 956   writer->write_classID(ik);
 957   writer->write_u4(STACK_TRACE_ID);
 958 
 959   // super class ID
 960   Klass* java_super = ik->java_super();
 961   if (java_super == NULL) {
 962     writer->write_objectID(oop(NULL));
 963   } else {
 964     writer->write_classID(java_super);
 965   }
 966 
 967   writer->write_objectID(ik->class_loader());
 968   writer->write_objectID(ik->signers());
 969   writer->write_objectID(ik->protection_domain());
 970 
 971   // reserved
 972   writer->write_objectID(oop(NULL));
 973   writer->write_objectID(oop(NULL));
 974 
 975   // instance size
 976   writer->write_u4(DumperSupport::instance_size(k));
 977 
 978   // size of constant pool - ignored by HAT 1.1
 979   writer->write_u2(0);
 980 
 981   // number of static fields
 982   dump_static_fields(writer, k);
 983 
 984   // description of instance fields
 985   dump_instance_field_descriptors(writer, k);
 986 
 987   // array classes
 988   k = klass->array_klass_or_null();
 989   while (k != NULL) {
 990     Klass* klass = k;
 991     assert(klass->oop_is_objArray(), "not an ObjArrayKlass");
 992 
 993     writer->write_u1(HPROF_GC_CLASS_DUMP);
 994     writer->write_classID(klass);
 995     writer->write_u4(STACK_TRACE_ID);
 996 
 997     // super class of array classes is java.lang.Object
 998     java_super = klass->java_super();
 999     assert(java_super != NULL, "checking");
1000     writer->write_classID(java_super);
1001 
1002     writer->write_objectID(ik->class_loader());
1003     writer->write_objectID(ik->signers());
1004     writer->write_objectID(ik->protection_domain());
1005 
1006     writer->write_objectID(oop(NULL));    // reserved
1007     writer->write_objectID(oop(NULL));
1008     writer->write_u4(0);             // instance size
1009     writer->write_u2(0);             // constant pool
1010     writer->write_u2(0);             // static fields
1011     writer->write_u2(0);             // instance fields
1012 
1013     // get the array class for the next rank
1014     k = klass->array_klass_or_null();
1015   }
1016 }
1017 
1018 // creates HPROF_GC_CLASS_DUMP record for a given primitive array
1019 // class (and each multi-dimensional array class too)
1020 void DumperSupport::dump_basic_type_array_class(DumpWriter* writer, Klass* k) {
1021  // array classes
1022  while (k != NULL) {
1023     Klass* klass = k;
1024 
1025     writer->write_u1(HPROF_GC_CLASS_DUMP);
1026     writer->write_classID(klass);
1027     writer->write_u4(STACK_TRACE_ID);
1028 
1029     // super class of array classes is java.lang.Object
1030     Klass* java_super = klass->java_super();
1031     assert(java_super != NULL, "checking");
1032     writer->write_classID(java_super);
1033 
1034     writer->write_objectID(oop(NULL));    // loader
1035     writer->write_objectID(oop(NULL));    // signers
1036     writer->write_objectID(oop(NULL));    // protection domain
1037 
1038     writer->write_objectID(oop(NULL));    // reserved
1039     writer->write_objectID(oop(NULL));
1040     writer->write_u4(0);             // instance size
1041     writer->write_u2(0);             // constant pool
1042     writer->write_u2(0);             // static fields
1043     writer->write_u2(0);             // instance fields
1044 
1045     // get the array class for the next rank
1046     k = klass->array_klass_or_null();
1047   }
1048 }
1049 
1050 // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
1051 void DumperSupport::dump_object_array(DumpWriter* writer, objArrayOop array) {
1052 
1053   writer->write_u1(HPROF_GC_OBJ_ARRAY_DUMP);
1054   writer->write_objectID(array);
1055   writer->write_u4(STACK_TRACE_ID);
1056   writer->write_u4((u4)array->length());
1057 
1058   // array class ID
1059   writer->write_classID(array->klass());
1060 
1061   // [id]* elements
1062   for (int index=0; index<array->length(); index++) {
1063     oop o = array->obj_at(index);
1064     writer->write_objectID(o);
1065   }
1066 }
1067 
1068 #define WRITE_ARRAY(Array, Type, Size) \
1069   for (int i=0; i<Array->length(); i++) { writer->write_##Size((Size)array->Type##_at(i)); }
1070 
1071 
1072 // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
1073 void DumperSupport::dump_prim_array(DumpWriter* writer, typeArrayOop array) {
1074   BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
1075 
1076   writer->write_u1(HPROF_GC_PRIM_ARRAY_DUMP);
1077   writer->write_objectID(array);
1078   writer->write_u4(STACK_TRACE_ID);
1079   writer->write_u4((u4)array->length());
1080   writer->write_u1(type2tag(type));
1081 
1082   // nothing to copy
1083   if (array->length() == 0) {
1084     return;
1085   }
1086 
1087   // If the byte ordering is big endian then we can copy most types directly
1088   u4 length_in_bytes = (u4)array->length() * type2aelembytes(type);
1089 
1090   switch (type) {
1091     case T_INT : {
1092       if (Bytes::is_Java_byte_ordering_different()) {
1093         WRITE_ARRAY(array, int, u4);
1094       } else {
1095         writer->write_raw((void*)(array->int_at_addr(0)), length_in_bytes);
1096       }
1097       break;
1098     }
1099     case T_BYTE : {
1100       writer->write_raw((void*)(array->byte_at_addr(0)), length_in_bytes);
1101       break;
1102     }
1103     case T_CHAR : {
1104       if (Bytes::is_Java_byte_ordering_different()) {
1105         WRITE_ARRAY(array, char, u2);
1106       } else {
1107         writer->write_raw((void*)(array->char_at_addr(0)), length_in_bytes);
1108       }
1109       break;
1110     }
1111     case T_SHORT : {
1112       if (Bytes::is_Java_byte_ordering_different()) {
1113         WRITE_ARRAY(array, short, u2);
1114       } else {
1115         writer->write_raw((void*)(array->short_at_addr(0)), length_in_bytes);
1116       }
1117       break;
1118     }
1119     case T_BOOLEAN : {
1120       if (Bytes::is_Java_byte_ordering_different()) {
1121         WRITE_ARRAY(array, bool, u1);
1122       } else {
1123         writer->write_raw((void*)(array->bool_at_addr(0)), length_in_bytes);
1124       }
1125       break;
1126     }
1127     case T_LONG : {
1128       if (Bytes::is_Java_byte_ordering_different()) {
1129         WRITE_ARRAY(array, long, u8);
1130       } else {
1131         writer->write_raw((void*)(array->long_at_addr(0)), length_in_bytes);
1132       }
1133       break;
1134     }
1135 
1136     // handle float/doubles in a special value to ensure than NaNs are
1137     // written correctly. TO DO: Check if we can avoid this on processors that
1138     // use IEEE 754.
1139 
1140     case T_FLOAT : {
1141       for (int i=0; i<array->length(); i++) {
1142         dump_float( writer, array->float_at(i) );
1143       }
1144       break;
1145     }
1146     case T_DOUBLE : {
1147       for (int i=0; i<array->length(); i++) {
1148         dump_double( writer, array->double_at(i) );
1149       }
1150       break;
1151     }
1152     default : ShouldNotReachHere();
1153   }
1154 }
1155 
1156 // create a HPROF_FRAME record of the given Method* and bci
1157 void DumperSupport::dump_stack_frame(DumpWriter* writer,
1158                                      int frame_serial_num,
1159                                      int class_serial_num,
1160                                      Method* m,
1161                                      int bci) {
1162   int line_number;
1163   if (m->is_native()) {
1164     line_number = -3;  // native frame
1165   } else {
1166     line_number = m->line_number_from_bci(bci);
1167   }
1168 
1169   write_header(writer, HPROF_FRAME, 4*oopSize + 2*sizeof(u4));
1170   writer->write_id(frame_serial_num);               // frame serial number
1171   writer->write_symbolID(m->name());                // method's name
1172   writer->write_symbolID(m->signature());           // method's signature
1173 
1174   assert(m->method_holder()->oop_is_instance(), "not InstanceKlass");
1175   writer->write_symbolID(m->method_holder()->source_file_name());  // source file name
1176   writer->write_u4(class_serial_num);               // class serial number
1177   writer->write_u4((u4) line_number);               // line number
1178 }
1179 
1180 
1181 // Support class used to generate HPROF_UTF8 records from the entries in the
1182 // SymbolTable.
1183 
1184 class SymbolTableDumper : public SymbolClosure {
1185  private:
1186   DumpWriter* _writer;
1187   DumpWriter* writer() const                { return _writer; }
1188  public:
1189   SymbolTableDumper(DumpWriter* writer)     { _writer = writer; }
1190   void do_symbol(Symbol** p);
1191 };
1192 
1193 void SymbolTableDumper::do_symbol(Symbol** p) {
1194   ResourceMark rm;
1195   Symbol* sym = load_symbol(p);
1196   int len = sym->utf8_length();
1197   if (len > 0) {
1198     char* s = sym->as_utf8();
1199     DumperSupport::write_header(writer(), HPROF_UTF8, oopSize + len);
1200     writer()->write_symbolID(sym);
1201     writer()->write_raw(s, len);
1202   }
1203 }
1204 
1205 // Support class used to generate HPROF_GC_ROOT_JNI_LOCAL records
1206 
1207 class JNILocalsDumper : public OopClosure {
1208  private:
1209   DumpWriter* _writer;
1210   u4 _thread_serial_num;
1211   int _frame_num;
1212   DumpWriter* writer() const                { return _writer; }
1213  public:
1214   JNILocalsDumper(DumpWriter* writer, u4 thread_serial_num) {
1215     _writer = writer;
1216     _thread_serial_num = thread_serial_num;
1217     _frame_num = -1;  // default - empty stack
1218   }
1219   void set_frame_number(int n) { _frame_num = n; }
1220   void do_oop(oop* obj_p);
1221   void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1222 };
1223 
1224 
1225 void JNILocalsDumper::do_oop(oop* obj_p) {
1226   // ignore null or deleted handles
1227   oop o = *obj_p;
1228   if (o != NULL && o != JNIHandles::deleted_handle()) {
1229     writer()->write_u1(HPROF_GC_ROOT_JNI_LOCAL);
1230     writer()->write_objectID(o);
1231     writer()->write_u4(_thread_serial_num);
1232     writer()->write_u4((u4)_frame_num);
1233   }
1234 }
1235 
1236 
1237 // Support class used to generate HPROF_GC_ROOT_JNI_GLOBAL records
1238 
1239 class JNIGlobalsDumper : public OopClosure {
1240  private:
1241   DumpWriter* _writer;
1242   DumpWriter* writer() const                { return _writer; }
1243 
1244  public:
1245   JNIGlobalsDumper(DumpWriter* writer) {
1246     _writer = writer;
1247   }
1248   void do_oop(oop* obj_p);
1249   void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1250 };
1251 
1252 void JNIGlobalsDumper::do_oop(oop* obj_p) {
1253   oop o = *obj_p;
1254 
1255   // ignore these
1256   if (o == NULL || o == JNIHandles::deleted_handle()) return;
1257 
1258   // we ignore global ref to symbols and other internal objects
1259   if (o->is_instance() || o->is_objArray() || o->is_typeArray()) {
1260     writer()->write_u1(HPROF_GC_ROOT_JNI_GLOBAL);
1261     writer()->write_objectID(o);
1262     writer()->write_objectID((oopDesc*)obj_p);      // global ref ID
1263   }
1264 };
1265 
1266 
1267 // Support class used to generate HPROF_GC_ROOT_MONITOR_USED records
1268 
1269 class MonitorUsedDumper : public OopClosure {
1270  private:
1271   DumpWriter* _writer;
1272   DumpWriter* writer() const                { return _writer; }
1273  public:
1274   MonitorUsedDumper(DumpWriter* writer) {
1275     _writer = writer;
1276   }
1277   void do_oop(oop* obj_p) {
1278     writer()->write_u1(HPROF_GC_ROOT_MONITOR_USED);
1279     writer()->write_objectID(*obj_p);
1280   }
1281   void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1282 };
1283 
1284 
1285 // Support class used to generate HPROF_GC_ROOT_STICKY_CLASS records
1286 
1287 class StickyClassDumper : public KlassClosure {
1288  private:
1289   DumpWriter* _writer;
1290   DumpWriter* writer() const                { return _writer; }
1291  public:
1292   StickyClassDumper(DumpWriter* writer) {
1293     _writer = writer;
1294   }
1295   void do_klass(Klass* k) {
1296     if (k->oop_is_instance()) {
1297       InstanceKlass* ik = InstanceKlass::cast(k);
1298         writer()->write_u1(HPROF_GC_ROOT_STICKY_CLASS);
1299         writer()->write_classID(ik);
1300       }
1301     }
1302 };
1303 
1304 
1305 class VM_HeapDumper;
1306 
1307 // Support class using when iterating over the heap.
1308 
1309 class HeapObjectDumper : public ObjectClosure {
1310  private:
1311   VM_HeapDumper* _dumper;
1312   DumpWriter* _writer;
1313 
1314   VM_HeapDumper* dumper()               { return _dumper; }
1315   DumpWriter* writer()                  { return _writer; }
1316 
1317   // used to indicate that a record has been writen
1318   void mark_end_of_record();
1319 
1320  public:
1321   HeapObjectDumper(VM_HeapDumper* dumper, DumpWriter* writer) {
1322     _dumper = dumper;
1323     _writer = writer;
1324   }
1325 
1326   // called for each object in the heap
1327   void do_object(oop o);
1328 };
1329 
1330 void HeapObjectDumper::do_object(oop o) {
1331   // hide the sentinel for deleted handles
1332   if (o == JNIHandles::deleted_handle()) return;
1333 
1334   // skip classes as these emitted as HPROF_GC_CLASS_DUMP records
1335   if (o->klass() == SystemDictionary::Class_klass()) {
1336     if (!java_lang_Class::is_primitive(o)) {
1337       return;
1338     }
1339   }
1340 
1341   if (o->is_instance()) {
1342     // create a HPROF_GC_INSTANCE record for each object
1343     DumperSupport::dump_instance(writer(), o);
1344     mark_end_of_record();
1345   } else if (o->is_objArray()) {
1346     // create a HPROF_GC_OBJ_ARRAY_DUMP record for each object array
1347     DumperSupport::dump_object_array(writer(), objArrayOop(o));
1348     mark_end_of_record();
1349   } else if (o->is_typeArray()) {
1350     // create a HPROF_GC_PRIM_ARRAY_DUMP record for each type array
1351     DumperSupport::dump_prim_array(writer(), typeArrayOop(o));
1352     mark_end_of_record();
1353   }
1354 }
1355 
1356 // The VM operation that performs the heap dump
1357 class VM_HeapDumper : public VM_GC_Operation {
1358  private:
1359   static VM_HeapDumper* _global_dumper;
1360   static DumpWriter*    _global_writer;
1361   DumpWriter*           _local_writer;
1362   JavaThread*           _oome_thread;
1363   Method*               _oome_constructor;
1364   bool _gc_before_heap_dump;
1365   bool _is_segmented_dump;
1366   jlong _dump_start;
1367   GrowableArray<Klass*>* _klass_map;
1368   ThreadStackTrace** _stack_traces;
1369   int _num_threads;
1370 
1371   // accessors and setters
1372   static VM_HeapDumper* dumper()         {  assert(_global_dumper != NULL, "Error"); return _global_dumper; }
1373   static DumpWriter* writer()            {  assert(_global_writer != NULL, "Error"); return _global_writer; }
1374   void set_global_dumper() {
1375     assert(_global_dumper == NULL, "Error");
1376     _global_dumper = this;
1377   }
1378   void set_global_writer() {
1379     assert(_global_writer == NULL, "Error");
1380     _global_writer = _local_writer;
1381   }
1382   void clear_global_dumper() { _global_dumper = NULL; }
1383   void clear_global_writer() { _global_writer = NULL; }
1384 
1385   bool is_segmented_dump() const                { return _is_segmented_dump; }
1386   void set_segmented_dump()                     { _is_segmented_dump = true; }
1387   jlong dump_start() const                      { return _dump_start; }
1388   void set_dump_start(jlong pos);
1389 
1390   bool skip_operation() const;
1391 
1392   // writes a HPROF_LOAD_CLASS record
1393   static void do_load_class(Klass* k);
1394 
1395   // writes a HPROF_GC_CLASS_DUMP record for the given class
1396   // (and each array class too)
1397   static void do_class_dump(Klass* k);
1398 
1399   // writes a HPROF_GC_CLASS_DUMP records for a given basic type
1400   // array (and each multi-dimensional array too)
1401   static void do_basic_type_array_class_dump(Klass* k);
1402 
1403   // HPROF_GC_ROOT_THREAD_OBJ records
1404   int do_thread(JavaThread* thread, u4 thread_serial_num);
1405   void do_threads();
1406 
1407   void add_class_serial_number(Klass* k, int serial_num) {
1408     _klass_map->at_put_grow(serial_num, k);
1409   }
1410 
1411   // HPROF_TRACE and HPROF_FRAME records
1412   void dump_stack_traces();
1413 
1414   // writes a HPROF_HEAP_DUMP or HPROF_HEAP_DUMP_SEGMENT record
1415   void write_dump_header();
1416 
1417   // fixes up the length of the current dump record
1418   void write_current_dump_record_length();
1419 
1420   // fixes up the current dump record )and writes HPROF_HEAP_DUMP_END
1421   // record in the case of a segmented heap dump)
1422   void end_of_dump();
1423 
1424  public:
1425   VM_HeapDumper(DumpWriter* writer, bool gc_before_heap_dump, bool oome) :
1426     VM_GC_Operation(0 /* total collections,      dummy, ignored */,
1427                     GCCause::_heap_dump /* GC Cause */,
1428                     0 /* total full collections, dummy, ignored */,
1429                     gc_before_heap_dump) {
1430     _local_writer = writer;
1431     _gc_before_heap_dump = gc_before_heap_dump;
1432     _is_segmented_dump = false;
1433     _dump_start = (jlong)-1;
1434     _klass_map = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<Klass*>(INITIAL_CLASS_COUNT, true);
1435     _stack_traces = NULL;
1436     _num_threads = 0;
1437     if (oome) {
1438       assert(!Thread::current()->is_VM_thread(), "Dump from OutOfMemoryError cannot be called by the VMThread");
1439       // get OutOfMemoryError zero-parameter constructor
1440       InstanceKlass* oome_ik = InstanceKlass::cast(SystemDictionary::OutOfMemoryError_klass());
1441       _oome_constructor = oome_ik->find_method(vmSymbols::object_initializer_name(),
1442                                                           vmSymbols::void_method_signature());
1443       // get thread throwing OOME when generating the heap dump at OOME
1444       _oome_thread = JavaThread::current();
1445     } else {
1446       _oome_thread = NULL;
1447       _oome_constructor = NULL;
1448     }
1449   }
1450   ~VM_HeapDumper() {
1451     if (_stack_traces != NULL) {
1452       for (int i=0; i < _num_threads; i++) {
1453         delete _stack_traces[i];
1454       }
1455       FREE_C_HEAP_ARRAY(ThreadStackTrace*, _stack_traces, mtInternal);
1456     }
1457     delete _klass_map;
1458   }
1459 
1460   VMOp_Type type() const { return VMOp_HeapDumper; }
1461   // used to mark sub-record boundary
1462   void check_segment_length();
1463   void doit();
1464 };
1465 
1466 VM_HeapDumper* VM_HeapDumper::_global_dumper = NULL;
1467 DumpWriter*    VM_HeapDumper::_global_writer = NULL;
1468 
1469 bool VM_HeapDumper::skip_operation() const {
1470   return false;
1471 }
1472 
1473 // sets the dump starting position
1474 void VM_HeapDumper::set_dump_start(jlong pos) {
1475   _dump_start = pos;
1476 }
1477 
1478  // writes a HPROF_HEAP_DUMP or HPROF_HEAP_DUMP_SEGMENT record
1479 void VM_HeapDumper::write_dump_header() {
1480   if (writer()->is_open()) {
1481     if (is_segmented_dump()) {
1482       writer()->write_u1(HPROF_HEAP_DUMP_SEGMENT);
1483     } else {
1484       writer()->write_u1(HPROF_HEAP_DUMP);
1485     }
1486     writer()->write_u4(0); // current ticks
1487 
1488     // record the starting position for the dump (its length will be fixed up later)
1489     set_dump_start(writer()->current_offset());
1490     writer()->write_u4(0);
1491   }
1492 }
1493 
1494 // fixes up the length of the current dump record
1495 void VM_HeapDumper::write_current_dump_record_length() {
1496   if (writer()->is_open()) {
1497     assert(dump_start() >= 0, "no dump start recorded");
1498 
1499     // calculate the size of the dump record
1500     julong dump_end = writer()->current_offset();
1501     julong dump_len = (dump_end - dump_start() - 4);
1502 
1503     // record length must fit in a u4
1504     if (dump_len > max_juint) {
1505       warning("record is too large");
1506     }
1507 
1508     // seek to the dump start and fix-up the length
1509     writer()->seek_to_offset(dump_start());
1510     writer()->write_u4((u4)dump_len);
1511 
1512     // adjust the total size written to keep the bytes written correct.
1513     writer()->adjust_bytes_written(-((jlong) sizeof(u4)));
1514 
1515     // seek to dump end so we can continue
1516     writer()->seek_to_offset(dump_end);
1517 
1518     // no current dump record
1519     set_dump_start((jlong)-1);
1520   }
1521 }
1522 
1523 // used on a sub-record boundary to check if we need to start a
1524 // new segment.
1525 void VM_HeapDumper::check_segment_length() {
1526   if (writer()->is_open()) {
1527     if (is_segmented_dump()) {
1528       // don't use current_offset that would be too expensive on a per record basis
1529       julong dump_end = writer()->bytes_written() + writer()->bytes_unwritten();
1530       assert(dump_end == (julong)writer()->current_offset(), "checking");
1531       julong dump_len = (dump_end - dump_start() - 4);
1532       assert(dump_len <= max_juint, "bad dump length");
1533 
1534       if (dump_len > HeapDumpSegmentSize) {
1535         write_current_dump_record_length();
1536         write_dump_header();
1537       }
1538     }
1539   }
1540 }
1541 
1542 // fixes up the current dump record )and writes HPROF_HEAP_DUMP_END
1543 // record in the case of a segmented heap dump)
1544 void VM_HeapDumper::end_of_dump() {
1545   if (writer()->is_open()) {
1546     write_current_dump_record_length();
1547 
1548     // for segmented dump we write the end record
1549     if (is_segmented_dump()) {
1550       writer()->write_u1(HPROF_HEAP_DUMP_END);
1551       writer()->write_u4(0);
1552       writer()->write_u4(0);
1553     }
1554   }
1555 }
1556 
1557 // marks sub-record boundary
1558 void HeapObjectDumper::mark_end_of_record() {
1559   dumper()->check_segment_length();
1560 }
1561 
1562 // writes a HPROF_LOAD_CLASS record for the class (and each of its
1563 // array classes)
1564 void VM_HeapDumper::do_load_class(Klass* k) {
1565   static u4 class_serial_num = 0;
1566 
1567   // len of HPROF_LOAD_CLASS record
1568   u4 remaining = 2*oopSize + 2*sizeof(u4);
1569 
1570   // write a HPROF_LOAD_CLASS for the class and each array class
1571   do {
1572     DumperSupport::write_header(writer(), HPROF_LOAD_CLASS, remaining);
1573 
1574     // class serial number is just a number
1575     writer()->write_u4(++class_serial_num);
1576 
1577     // class ID
1578     Klass* klass = k;
1579     writer()->write_classID(klass);
1580 
1581     // add the Klass* and class serial number pair
1582     dumper()->add_class_serial_number(klass, class_serial_num);
1583 
1584     writer()->write_u4(STACK_TRACE_ID);
1585 
1586     // class name ID
1587     Symbol* name = klass->name();
1588     writer()->write_symbolID(name);
1589 
1590     // write a LOAD_CLASS record for the array type (if it exists)
1591     k = klass->array_klass_or_null();
1592   } while (k != NULL);
1593 }
1594 
1595 // writes a HPROF_GC_CLASS_DUMP record for the given class
1596 void VM_HeapDumper::do_class_dump(Klass* k) {
1597   if (k->oop_is_instance()) {
1598     DumperSupport::dump_class_and_array_classes(writer(), k);
1599   }
1600 }
1601 
1602 // writes a HPROF_GC_CLASS_DUMP records for a given basic type
1603 // array (and each multi-dimensional array too)
1604 void VM_HeapDumper::do_basic_type_array_class_dump(Klass* k) {
1605   DumperSupport::dump_basic_type_array_class(writer(), k);
1606 }
1607 
1608 // Walk the stack of the given thread.
1609 // Dumps a HPROF_GC_ROOT_JAVA_FRAME record for each local
1610 // Dumps a HPROF_GC_ROOT_JNI_LOCAL record for each JNI local
1611 //
1612 // It returns the number of Java frames in this thread stack
1613 int VM_HeapDumper::do_thread(JavaThread* java_thread, u4 thread_serial_num) {
1614   JNILocalsDumper blk(writer(), thread_serial_num);
1615 
1616   oop threadObj = java_thread->threadObj();
1617   assert(threadObj != NULL, "sanity check");
1618 
1619   int stack_depth = 0;
1620   if (java_thread->has_last_Java_frame()) {
1621 
1622     // vframes are resource allocated
1623     Thread* current_thread = Thread::current();
1624     ResourceMark rm(current_thread);
1625     HandleMark hm(current_thread);
1626 
1627     RegisterMap reg_map(java_thread);
1628     frame f = java_thread->last_frame();
1629     vframe* vf = vframe::new_vframe(&f, &reg_map, java_thread);
1630     frame* last_entry_frame = NULL;
1631     int extra_frames = 0;
1632 
1633     if (java_thread == _oome_thread && _oome_constructor != NULL) {
1634       extra_frames++;
1635     }
1636     while (vf != NULL) {
1637       blk.set_frame_number(stack_depth);
1638       if (vf->is_java_frame()) {
1639 
1640         // java frame (interpreted, compiled, ...)
1641         javaVFrame *jvf = javaVFrame::cast(vf);
1642         if (!(jvf->method()->is_native())) {
1643           StackValueCollection* locals = jvf->locals();
1644           for (int slot=0; slot<locals->size(); slot++) {
1645             if (locals->at(slot)->type() == T_OBJECT) {
1646               oop o = locals->obj_at(slot)();
1647 
1648               if (o != NULL) {
1649                 writer()->write_u1(HPROF_GC_ROOT_JAVA_FRAME);
1650                 writer()->write_objectID(o);
1651                 writer()->write_u4(thread_serial_num);
1652                 writer()->write_u4((u4) (stack_depth + extra_frames));
1653               }
1654             }
1655           }
1656         } else {
1657           // native frame
1658           if (stack_depth == 0) {
1659             // JNI locals for the top frame.
1660             java_thread->active_handles()->oops_do(&blk);
1661           } else {
1662             if (last_entry_frame != NULL) {
1663               // JNI locals for the entry frame
1664               assert(last_entry_frame->is_entry_frame(), "checking");
1665               last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(&blk);
1666             }
1667           }
1668         }
1669         // increment only for Java frames
1670         stack_depth++;
1671         last_entry_frame = NULL;
1672 
1673       } else {
1674         // externalVFrame - if it's an entry frame then report any JNI locals
1675         // as roots when we find the corresponding native javaVFrame
1676         frame* fr = vf->frame_pointer();
1677         assert(fr != NULL, "sanity check");
1678         if (fr->is_entry_frame()) {
1679           last_entry_frame = fr;
1680         }
1681       }
1682       vf = vf->sender();
1683     }
1684   } else {
1685     // no last java frame but there may be JNI locals
1686     java_thread->active_handles()->oops_do(&blk);
1687   }
1688   return stack_depth;
1689 }
1690 
1691 
1692 // write a HPROF_GC_ROOT_THREAD_OBJ record for each java thread. Then walk
1693 // the stack so that locals and JNI locals are dumped.
1694 void VM_HeapDumper::do_threads() {
1695   for (int i=0; i < _num_threads; i++) {
1696     JavaThread* thread = _stack_traces[i]->thread();
1697     oop threadObj = thread->threadObj();
1698     u4 thread_serial_num = i+1;
1699     u4 stack_serial_num = thread_serial_num + STACK_TRACE_ID;
1700     writer()->write_u1(HPROF_GC_ROOT_THREAD_OBJ);
1701     writer()->write_objectID(threadObj);
1702     writer()->write_u4(thread_serial_num);  // thread number
1703     writer()->write_u4(stack_serial_num);   // stack trace serial number
1704     int num_frames = do_thread(thread, thread_serial_num);
1705     assert(num_frames == _stack_traces[i]->get_stack_depth(),
1706            "total number of Java frames not matched");
1707   }
1708 }
1709 
1710 
1711 // The VM operation that dumps the heap. The dump consists of the following
1712 // records:
1713 //
1714 //  HPROF_HEADER
1715 //  [HPROF_UTF8]*
1716 //  [HPROF_LOAD_CLASS]*
1717 //  [[HPROF_FRAME]*|HPROF_TRACE]*
1718 //  [HPROF_GC_CLASS_DUMP]*
1719 //  HPROF_HEAP_DUMP
1720 //
1721 // The HPROF_TRACE records represent the stack traces where the heap dump
1722 // is generated and a "dummy trace" record which does not include
1723 // any frames. The dummy trace record is used to be referenced as the
1724 // unknown object alloc site.
1725 //
1726 // The HPROF_HEAP_DUMP record has a length following by sub-records. To allow
1727 // the heap dump be generated in a single pass we remember the position of
1728 // the dump length and fix it up after all sub-records have been written.
1729 // To generate the sub-records we iterate over the heap, writing
1730 // HPROF_GC_INSTANCE_DUMP, HPROF_GC_OBJ_ARRAY_DUMP, and HPROF_GC_PRIM_ARRAY_DUMP
1731 // records as we go. Once that is done we write records for some of the GC
1732 // roots.
1733 
1734 void VM_HeapDumper::doit() {
1735 
1736   HandleMark hm;
1737   CollectedHeap* ch = Universe::heap();
1738 
1739   ch->ensure_parsability(false); // must happen, even if collection does
1740                                  // not happen (e.g. due to GC_locker)
1741 
1742   if (_gc_before_heap_dump) {
1743     if (GC_locker::is_active()) {
1744       warning("GC locker is held; pre-heapdump GC was skipped");
1745     } else {
1746       ch->collect_as_vm_thread(GCCause::_heap_dump);
1747     }
1748   }
1749 
1750   // At this point we should be the only dumper active, so
1751   // the following should be safe.
1752   set_global_dumper();
1753   set_global_writer();
1754 
1755   // Write the file header - use 1.0.2 for large heaps, otherwise 1.0.1
1756   size_t used = ch->used();
1757   const char* header;
1758   if (used > (size_t)SegmentedHeapDumpThreshold) {
1759     set_segmented_dump();
1760     header = "JAVA PROFILE 1.0.2";
1761   } else {
1762     header = "JAVA PROFILE 1.0.1";
1763   }
1764 
1765   // header is few bytes long - no chance to overflow int
1766   writer()->write_raw((void*)header, (int)strlen(header));
1767   writer()->write_u1(0); // terminator
1768   writer()->write_u4(oopSize);
1769   writer()->write_u8(os::javaTimeMillis());
1770 
1771   // HPROF_UTF8 records
1772   SymbolTableDumper sym_dumper(writer());
1773   SymbolTable::symbols_do(&sym_dumper);
1774 
1775   // write HPROF_LOAD_CLASS records
1776   ClassLoaderDataGraph::classes_do(&do_load_class);
1777   Universe::basic_type_classes_do(&do_load_class);
1778 
1779   // write HPROF_FRAME and HPROF_TRACE records
1780   // this must be called after _klass_map is built when iterating the classes above.
1781   dump_stack_traces();
1782 
1783   // write HPROF_HEAP_DUMP or HPROF_HEAP_DUMP_SEGMENT
1784   write_dump_header();
1785 
1786   // Writes HPROF_GC_CLASS_DUMP records
1787   ClassLoaderDataGraph::classes_do(&do_class_dump);
1788   Universe::basic_type_classes_do(&do_basic_type_array_class_dump);
1789   check_segment_length();
1790 
1791   // writes HPROF_GC_INSTANCE_DUMP records.
1792   // After each sub-record is written check_segment_length will be invoked. When
1793   // generated a segmented heap dump this allows us to check if the current
1794   // segment exceeds a threshold and if so, then a new segment is started.
1795   // The HPROF_GC_CLASS_DUMP and HPROF_GC_INSTANCE_DUMP are the vast bulk
1796   // of the heap dump.
1797   HeapObjectDumper obj_dumper(this, writer());
1798   Universe::heap()->safe_object_iterate(&obj_dumper);
1799 
1800   // HPROF_GC_ROOT_THREAD_OBJ + frames + jni locals
1801   do_threads();
1802   check_segment_length();
1803 
1804   // HPROF_GC_ROOT_MONITOR_USED
1805   MonitorUsedDumper mon_dumper(writer());
1806   ObjectSynchronizer::oops_do(&mon_dumper);
1807   check_segment_length();
1808 
1809   // HPROF_GC_ROOT_JNI_GLOBAL
1810   JNIGlobalsDumper jni_dumper(writer());
1811   JNIHandles::oops_do(&jni_dumper);
1812   Universe::oops_do(&jni_dumper);  // technically not jni roots, but global roots
1813                                    // for things like preallocated throwable backtraces
1814   check_segment_length();
1815 
1816   // HPROF_GC_ROOT_STICKY_CLASS
1817   StickyClassDumper class_dumper(writer());
1818   SystemDictionary::always_strong_classes_do(&class_dumper);
1819 
1820   // fixes up the length of the dump record. In the case of a segmented
1821   // heap then the HPROF_HEAP_DUMP_END record is also written.
1822   end_of_dump();
1823 
1824   // Now we clear the global variables, so that a future dumper might run.
1825   clear_global_dumper();
1826   clear_global_writer();
1827 }
1828 
1829 void VM_HeapDumper::dump_stack_traces() {
1830   // write a HPROF_TRACE record without any frames to be referenced as object alloc sites
1831   DumperSupport::write_header(writer(), HPROF_TRACE, 3*sizeof(u4));
1832   writer()->write_u4((u4) STACK_TRACE_ID);
1833   writer()->write_u4(0);                    // thread number
1834   writer()->write_u4(0);                    // frame count
1835 
1836   _stack_traces = NEW_C_HEAP_ARRAY(ThreadStackTrace*, Threads::number_of_threads(), mtInternal);
1837   int frame_serial_num = 0;
1838   for (JavaThread* thread = Threads::first(); thread != NULL ; thread = thread->next()) {
1839     oop threadObj = thread->threadObj();
1840     if (threadObj != NULL && !thread->is_exiting() && !thread->is_hidden_from_external_view()) {
1841       // dump thread stack trace
1842       ThreadStackTrace* stack_trace = new ThreadStackTrace(thread, false);
1843       stack_trace->dump_stack_at_safepoint(-1);
1844       _stack_traces[_num_threads++] = stack_trace;
1845 
1846       // write HPROF_FRAME records for this thread's stack trace
1847       int depth = stack_trace->get_stack_depth();
1848       int thread_frame_start = frame_serial_num;
1849       int extra_frames = 0;
1850       // write fake frame that makes it look like the thread, which caused OOME,
1851       // is in the OutOfMemoryError zero-parameter constructor
1852       if (thread == _oome_thread && _oome_constructor != NULL) {
1853         int oome_serial_num = _klass_map->find(_oome_constructor->method_holder());
1854         // the class serial number starts from 1
1855         assert(oome_serial_num > 0, "OutOfMemoryError class not found");
1856         DumperSupport::dump_stack_frame(writer(), ++frame_serial_num, oome_serial_num,
1857                                         _oome_constructor, 0);
1858         extra_frames++;
1859       }
1860       for (int j=0; j < depth; j++) {
1861         StackFrameInfo* frame = stack_trace->stack_frame_at(j);
1862         Method* m = frame->method();
1863         int class_serial_num = _klass_map->find(m->method_holder());
1864         // the class serial number starts from 1
1865         assert(class_serial_num > 0, "class not found");
1866         DumperSupport::dump_stack_frame(writer(), ++frame_serial_num, class_serial_num, m, frame->bci());
1867       }
1868       depth += extra_frames;
1869 
1870       // write HPROF_TRACE record for one thread
1871       DumperSupport::write_header(writer(), HPROF_TRACE, 3*sizeof(u4) + depth*oopSize);
1872       int stack_serial_num = _num_threads + STACK_TRACE_ID;
1873       writer()->write_u4(stack_serial_num);      // stack trace serial number
1874       writer()->write_u4((u4) _num_threads);     // thread serial number
1875       writer()->write_u4(depth);                 // frame count
1876       for (int j=1; j <= depth; j++) {
1877         writer()->write_id(thread_frame_start + j);
1878       }
1879     }
1880   }
1881 }
1882 
1883 // dump the heap to given path.
1884 PRAGMA_FORMAT_NONLITERAL_IGNORED_EXTERNAL
1885 int HeapDumper::dump(const char* path) {
1886   assert(path != NULL && strlen(path) > 0, "path missing");
1887 
1888   // print message in interactive case
1889   if (print_to_tty()) {
1890     tty->print_cr("Dumping heap to %s ...", path);
1891     timer()->start();
1892   }
1893 
1894   // create the dump writer. If the file can be opened then bail
1895   DumpWriter writer(path);
1896   if (!writer.is_open()) {
1897     set_error(writer.error());
1898     if (print_to_tty()) {
1899       tty->print_cr("Unable to create %s: %s", path,
1900         (error() != NULL) ? error() : "reason unknown");
1901     }
1902     return -1;
1903   }
1904 
1905   // generate the dump
1906   VM_HeapDumper dumper(&writer, _gc_before_heap_dump, _oome);
1907   if (Thread::current()->is_VM_thread()) {
1908     assert(SafepointSynchronize::is_at_safepoint(), "Expected to be called at a safepoint");
1909     dumper.doit();
1910   } else {
1911     VMThread::execute(&dumper);
1912   }
1913 
1914   // close dump file and record any error that the writer may have encountered
1915   writer.close();
1916   set_error(writer.error());
1917 
1918   // print message in interactive case
1919   if (print_to_tty()) {
1920     timer()->stop();
1921     if (error() == NULL) {
1922       tty->print_cr("Heap dump file created [" JULONG_FORMAT " bytes in %3.3f secs]",
1923                     writer.bytes_written(), timer()->seconds());
1924     } else {
1925       tty->print_cr("Dump file is incomplete: %s", writer.error());
1926     }
1927   }
1928 
1929   return (writer.error() == NULL) ? 0 : -1;
1930 }
1931 
1932 // stop timer (if still active), and free any error string we might be holding
1933 HeapDumper::~HeapDumper() {
1934   if (timer()->is_active()) {
1935     timer()->stop();
1936   }
1937   set_error(NULL);
1938 }
1939 
1940 
1941 // returns the error string (resource allocated), or NULL
1942 char* HeapDumper::error_as_C_string() const {
1943   if (error() != NULL) {
1944     char* str = NEW_RESOURCE_ARRAY(char, strlen(error())+1);
1945     strcpy(str, error());
1946     return str;
1947   } else {
1948     return NULL;
1949   }
1950 }
1951 
1952 // set the error string
1953 void HeapDumper::set_error(char* error) {
1954   if (_error != NULL) {
1955     os::free(_error);
1956   }
1957   if (error == NULL) {
1958     _error = NULL;
1959   } else {
1960     _error = os::strdup(error);
1961     assert(_error != NULL, "allocation failure");
1962   }
1963 }
1964 
1965 // Called by out-of-memory error reporting by a single Java thread
1966 // outside of a JVM safepoint
1967 void HeapDumper::dump_heap_from_oome() {
1968   HeapDumper::dump_heap(true);
1969 }
1970 
1971 // Called by error reporting by a single Java thread outside of a JVM safepoint,
1972 // or by heap dumping by the VM thread during a (GC) safepoint. Thus, these various
1973 // callers are strictly serialized and guaranteed not to interfere below. For more
1974 // general use, however, this method will need modification to prevent
1975 // inteference when updating the static variables base_path and dump_file_seq below.
1976 void HeapDumper::dump_heap() {
1977   HeapDumper::dump_heap(false);
1978 }
1979 
1980 void HeapDumper::dump_heap(bool oome) {
1981   static char base_path[JVM_MAXPATHLEN] = {'\0'};
1982   static uint dump_file_seq = 0;
1983   char* my_path;
1984   const int max_digit_chars = 20;
1985 
1986   const char* dump_file_name = "java_pid";
1987   const char* dump_file_ext  = ".hprof";
1988 
1989   // The dump file defaults to java_pid<pid>.hprof in the current working
1990   // directory. HeapDumpPath=<file> can be used to specify an alternative
1991   // dump file name or a directory where dump file is created.
1992   if (dump_file_seq == 0) { // first time in, we initialize base_path
1993     // Calculate potentially longest base path and check if we have enough
1994     // allocated statically.
1995     const size_t total_length =
1996                       (HeapDumpPath == NULL ? 0 : strlen(HeapDumpPath)) +
1997                       strlen(os::file_separator()) + max_digit_chars +
1998                       strlen(dump_file_name) + strlen(dump_file_ext) + 1;
1999     if (total_length > sizeof(base_path)) {
2000       warning("Cannot create heap dump file.  HeapDumpPath is too long.");
2001       return;
2002     }
2003 
2004     bool use_default_filename = true;
2005     if (HeapDumpPath == NULL || HeapDumpPath[0] == '\0') {
2006       // HeapDumpPath=<file> not specified
2007     } else {
2008       strncpy(base_path, HeapDumpPath, sizeof(base_path));
2009       // check if the path is a directory (must exist)
2010       DIR* dir = os::opendir(base_path);
2011       if (dir == NULL) {
2012         use_default_filename = false;
2013       } else {
2014         // HeapDumpPath specified a directory. We append a file separator
2015         // (if needed).
2016         os::closedir(dir);
2017         size_t fs_len = strlen(os::file_separator());
2018         if (strlen(base_path) >= fs_len) {
2019           char* end = base_path;
2020           end += (strlen(base_path) - fs_len);
2021           if (strcmp(end, os::file_separator()) != 0) {
2022             strcat(base_path, os::file_separator());
2023           }
2024         }
2025       }
2026     }
2027     // If HeapDumpPath wasn't a file name then we append the default name
2028     if (use_default_filename) {
2029       const size_t dlen = strlen(base_path);  // if heap dump dir specified
2030       jio_snprintf(&base_path[dlen], sizeof(base_path)-dlen, "%s%d%s",
2031                    dump_file_name, os::current_process_id(), dump_file_ext);
2032     }
2033     const size_t len = strlen(base_path) + 1;
2034     my_path = (char*)os::malloc(len, mtInternal);
2035     if (my_path == NULL) {
2036       warning("Cannot create heap dump file.  Out of system memory.");
2037       return;
2038     }
2039     strncpy(my_path, base_path, len);
2040   } else {
2041     // Append a sequence number id for dumps following the first
2042     const size_t len = strlen(base_path) + max_digit_chars + 2; // for '.' and \0
2043     my_path = (char*)os::malloc(len, mtInternal);
2044     if (my_path == NULL) {
2045       warning("Cannot create heap dump file.  Out of system memory.");
2046       return;
2047     }
2048     jio_snprintf(my_path, len, "%s.%d", base_path, dump_file_seq);
2049   }
2050   dump_file_seq++;   // increment seq number for next time we dump
2051 
2052   HeapDumper dumper(false /* no GC before heap dump */,
2053                     true  /* send to tty */,
2054                     oome  /* pass along out-of-memory-error flag */);
2055   dumper.dump(my_path);
2056   os::free(my_path);
2057 }