Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 2005, 2018, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  *

  */

 #include "precompiled.hpp"

 #include "classfile/symbolTable.hpp"

 #include "classfile/systemDictionary.hpp"

 #include "classfile/vmSymbols.hpp"

 #include "gc_implementation/shared/vmGCOperations.hpp"

 #include "memory/gcLocker.inline.hpp"

 #include "memory/genCollectedHeap.hpp"

 #include "memory/universe.hpp"

 #include "oops/objArrayKlass.hpp"

 #include "runtime/javaCalls.hpp"

 #include "runtime/jniHandles.hpp"

 #include "runtime/reflectionUtils.hpp"

 #include "runtime/vframe.hpp"

 #include "runtime/vmThread.hpp"

 #include "runtime/vm_operations.hpp"

 #include "services/heapDumper.hpp"

 #include "services/threadService.hpp"

 #include "utilities/ostream.hpp"

 #include "utilities/macros.hpp"

 #if INCLUDE_ALL_GCS

 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"

 #endif // INCLUDE_ALL_GCS

 /*

  * HPROF binary format - description copied from:

  *   src/share/demo/jvmti/hprof/hprof_io.c

  *

  *

  *  header    "JAVA PROFILE 1.0.2" (0-terminated)

  *

  *  u4        size of identifiers. Identifiers are used to represent

  *            UTF8 strings, objects, stack traces, etc. They usually

  *            have the same size as host pointers. For example, on

  *            Solaris and Win32, the size is 4.

  * u4         high word

  * u4         low word    number of milliseconds since 0:00 GMT, 1/1/70

  * [record]*  a sequence of records.

  *

  *

  * Record format:

  *

  * u1         a TAG denoting the type of the record

  * u4         number of *microseconds* since the time stamp in the

  *            header. (wraps around in a little more than an hour)

  * u4         number of bytes *remaining* in the record. Note that

  *            this number excludes the tag and the length field itself.

  * [u1]*      BODY of the record (a sequence of bytes)

  *

  *

  * The following TAGs are supported:

  *

  * TAG           BODY       notes

  *----------------------------------------------------------

  * HPROF_UTF8               a UTF8-encoded name

  *

  *               id         name ID

  *               [u1]*      UTF8 characters (no trailing zero)

  *

  * HPROF_LOAD_CLASS         a newly loaded class

  *

  *                u4        class serial number (> 0)

  *                id        class object ID

  *                u4        stack trace serial number

  *                id        class name ID

  *

  * HPROF_UNLOAD_CLASS       an unloading class

  *

  *                u4        class serial_number

  *

  * HPROF_FRAME              a Java stack frame

  *

  *                id        stack frame ID

  *                id        method name ID

  *                id        method signature ID

  *                id        source file name ID

  *                u4        class serial number

  *                i4        line number. >0: normal

  *                                       -1: unknown

  *                                       -2: compiled method

  *                                       -3: native method

  *

  * HPROF_TRACE              a Java stack trace

  *

  *               u4         stack trace serial number

  *               u4         thread serial number

  *               u4         number of frames

  *               [id]*      stack frame IDs

  *

  *

  * HPROF_ALLOC_SITES        a set of heap allocation sites, obtained after GC

  *

  *               u2         flags 0x0001: incremental vs. complete

  *                                0x0002: sorted by allocation vs. live

  *                                0x0004: whether to force a GC

  *               u4         cutoff ratio

  *               u4         total live bytes

  *               u4         total live instances

  *               u8         total bytes allocated

  *               u8         total instances allocated

  *               u4         number of sites that follow

  *               [u1        is_array: 0:  normal object

  *                                    2:  object array

  *                                    4:  boolean array

  *                                    5:  char array

  *                                    6:  float array

  *                                    7:  double array

  *                                    8:  byte array

  *                                    9:  short array

  *                                    10: int array

  *                                    11: long array

  *                u4        class serial number (may be zero during startup)

  *                u4        stack trace serial number

  *                u4        number of bytes alive

  *                u4        number of instances alive

  *                u4        number of bytes allocated

  *                u4]*      number of instance allocated

  *

  * HPROF_START_THREAD       a newly started thread.

  *

  *               u4         thread serial number (> 0)

  *               id         thread object ID

  *               u4         stack trace serial number

  *               id         thread name ID

  *               id         thread group name ID

  *               id         thread group parent name ID

  *

  * HPROF_END_THREAD         a terminating thread.

  *

  *               u4         thread serial number

  *

  * HPROF_HEAP_SUMMARY       heap summary

  *

  *               u4         total live bytes

  *               u4         total live instances

  *               u8         total bytes allocated

  *               u8         total instances allocated

  *

  * HPROF_HEAP_DUMP          denote a heap dump

  *

  *               [heap dump sub-records]*

  *

  *                          There are four kinds of heap dump sub-records:

  *

  *               u1         sub-record type

  *

  *               HPROF_GC_ROOT_UNKNOWN         unknown root

  *

  *                          id         object ID

  *

  *               HPROF_GC_ROOT_THREAD_OBJ      thread object

  *

  *                          id         thread object ID  (may be 0 for a

  *                                     thread newly attached through JNI)

  *                          u4         thread sequence number

  *                          u4         stack trace sequence number

  *

  *               HPROF_GC_ROOT_JNI_GLOBAL      JNI global ref root

  *

  *                          id         object ID

  *                          id         JNI global ref ID

  *

  *               HPROF_GC_ROOT_JNI_LOCAL       JNI local ref

  *

  *                          id         object ID

  *                          u4         thread serial number

  *                          u4         frame # in stack trace (-1 for empty)

  *

  *               HPROF_GC_ROOT_JAVA_FRAME      Java stack frame

  *

  *                          id         object ID

  *                          u4         thread serial number

  *                          u4         frame # in stack trace (-1 for empty)

  *

  *               HPROF_GC_ROOT_NATIVE_STACK    Native stack

  *

  *                          id         object ID

  *                          u4         thread serial number

  *

  *               HPROF_GC_ROOT_STICKY_CLASS    System class

  *

  *                          id         object ID

  *

  *               HPROF_GC_ROOT_THREAD_BLOCK    Reference from thread block

  *

  *                          id         object ID

  *                          u4         thread serial number

  *

  *               HPROF_GC_ROOT_MONITOR_USED    Busy monitor

  *

  *                          id         object ID

  *

  *               HPROF_GC_CLASS_DUMP           dump of a class object

  *

  *                          id         class object ID

  *                          u4         stack trace serial number

  *                          id         super class object ID

  *                          id         class loader object ID

  *                          id         signers object ID

  *                          id         protection domain object ID

  *                          id         reserved

  *                          id         reserved

  *

  *                          u4         instance size (in bytes)

  *

  *                          u2         size of constant pool

  *                          [u2,       constant pool index,

  *                           ty,       type

  *                                     2:  object

  *                                     4:  boolean

  *                                     5:  char

  *                                     6:  float

  *                                     7:  double

  *                                     8:  byte

  *                                     9:  short

  *                                     10: int

  *                                     11: long

  *                           vl]*      and value

  *

  *                          u2         number of static fields

  *                          [id,       static field name,

  *                           ty,       type,

  *                           vl]*      and value

  *

  *                          u2         number of inst. fields (not inc. super)

  *                          [id,       instance field name,

  *                           ty]*      type

  *

  *               HPROF_GC_INSTANCE_DUMP        dump of a normal object

  *

  *                          id         object ID

  *                          u4         stack trace serial number

  *                          id         class object ID

  *                          u4         number of bytes that follow

  *                          [vl]*      instance field values (class, followed

  *                                     by super, super's super ...)

  *

  *               HPROF_GC_OBJ_ARRAY_DUMP       dump of an object array

  *

  *                          id         array object ID

  *                          u4         stack trace serial number

  *                          u4         number of elements

  *                          id         array class ID

  *                          [id]*      elements

  *

  *               HPROF_GC_PRIM_ARRAY_DUMP      dump of a primitive array

  *

  *                          id         array object ID

  *                          u4         stack trace serial number

  *                          u4         number of elements

  *                          u1         element type

  *                                     4:  boolean array

  *                                     5:  char array

  *                                     6:  float array

  *                                     7:  double array

  *                                     8:  byte array

  *                                     9:  short array

  *                                     10: int array

  *                                     11: long array

  *                          [u1]*      elements

  *

  * HPROF_CPU_SAMPLES        a set of sample traces of running threads

  *

  *                u4        total number of samples

  *                u4        # of traces

  *               [u4        # of samples

  *                u4]*      stack trace serial number

  *

  * HPROF_CONTROL_SETTINGS   the settings of on/off switches

  *

  *                u4        0x00000001: alloc traces on/off

  *                          0x00000002: cpu sampling on/off

  *                u2        stack trace depth

  *

  *

  * When the header is "JAVA PROFILE 1.0.2" a heap dump can optionally

  * be generated as a sequence of heap dump segments. This sequence is

  * terminated by an end record. The additional tags allowed by format

  * "JAVA PROFILE 1.0.2" are:

  *

  * HPROF_HEAP_DUMP_SEGMENT  denote a heap dump segment

  *

  *               [heap dump sub-records]*

  *               The same sub-record types allowed by HPROF_HEAP_DUMP

  *

  * HPROF_HEAP_DUMP_END      denotes the end of a heap dump

  *

  */

 // HPROF tags

 typedef enum {

   // top-level records

   HPROF_UTF8                    = 0x01,

   HPROF_LOAD_CLASS              = 0x02,

   HPROF_UNLOAD_CLASS            = 0x03,

   HPROF_FRAME                   = 0x04,

   HPROF_TRACE                   = 0x05,

   HPROF_ALLOC_SITES             = 0x06,

   HPROF_HEAP_SUMMARY            = 0x07,

   HPROF_START_THREAD            = 0x0A,

   HPROF_END_THREAD              = 0x0B,

   HPROF_HEAP_DUMP               = 0x0C,

   HPROF_CPU_SAMPLES             = 0x0D,

   HPROF_CONTROL_SETTINGS        = 0x0E,

   // 1.0.2 record types

   HPROF_HEAP_DUMP_SEGMENT       = 0x1C,

   HPROF_HEAP_DUMP_END           = 0x2C,

   // field types

   HPROF_ARRAY_OBJECT            = 0x01,

   HPROF_NORMAL_OBJECT           = 0x02,

   HPROF_BOOLEAN                 = 0x04,

   HPROF_CHAR                    = 0x05,

   HPROF_FLOAT                   = 0x06,

   HPROF_DOUBLE                  = 0x07,

   HPROF_BYTE                    = 0x08,

   HPROF_SHORT                   = 0x09,

   HPROF_INT                     = 0x0A,

   HPROF_LONG                    = 0x0B,

   // data-dump sub-records

   HPROF_GC_ROOT_UNKNOWN         = 0xFF,

   HPROF_GC_ROOT_JNI_GLOBAL      = 0x01,

   HPROF_GC_ROOT_JNI_LOCAL       = 0x02,

   HPROF_GC_ROOT_JAVA_FRAME      = 0x03,

   HPROF_GC_ROOT_NATIVE_STACK    = 0x04,

   HPROF_GC_ROOT_STICKY_CLASS    = 0x05,

   HPROF_GC_ROOT_THREAD_BLOCK    = 0x06,

   HPROF_GC_ROOT_MONITOR_USED    = 0x07,

   HPROF_GC_ROOT_THREAD_OBJ      = 0x08,

   HPROF_GC_CLASS_DUMP           = 0x20,

   HPROF_GC_INSTANCE_DUMP        = 0x21,

   HPROF_GC_OBJ_ARRAY_DUMP       = 0x22,

   HPROF_GC_PRIM_ARRAY_DUMP      = 0x23

 } hprofTag;

 // Default stack trace ID (used for dummy HPROF_TRACE record)

 enum {

   STACK_TRACE_ID = 1,

   INITIAL_CLASS_COUNT = 200

 };

 // Supports I/O operations on a dump file

 class DumpWriter : public StackObj {

  private:

   enum {

     io_buffer_size  = 8*M

   };

   int _fd;              // file descriptor (-1 if dump file not open)

   julong _bytes_written; // number of byte written to dump file

   char* _buffer;    // internal buffer

   size_t _size;

   size_t _pos;

   jlong _dump_start;

   char* _error;   // error message when I/O fails

   void set_file_descriptor(int fd)              { _fd = fd; }

   int file_descriptor() const                   { return _fd; }

   char* buffer() const                          { return _buffer; }

   size_t buffer_size() const                    { return _size; }

   size_t position() const                       { return _pos; }

   void set_position(size_t pos)                 { _pos = pos; }

   void set_error(const char* error)             { _error = (char*)os::strdup(error); }

   // all I/O go through this function

   void write_internal(void* s, size_t len);

  public:

   DumpWriter(const char* path);

   ~DumpWriter();

   void close();

   bool is_open() const                  { return file_descriptor() >= 0; }

   void flush();

   jlong dump_start() const                      { return _dump_start; }

   void set_dump_start(jlong pos);

   julong current_record_length();

   // total number of bytes written to the disk

   julong bytes_written() const          { return _bytes_written; }

   // adjust the number of bytes written to disk (used to keep the count

   // of the number of bytes written in case of rewrites)

   void adjust_bytes_written(jlong n)    { _bytes_written += n; }

   // number of (buffered) bytes as yet unwritten to the dump file

   size_t bytes_unwritten() const        { return position(); }

   char* error() const                   { return _error; }

   jlong current_offset();

   void seek_to_offset(jlong pos);

   // writer functions

   void write_raw(void* s, size_t len);

   void write_u1(u1 x)                   { write_raw((void*)&x, 1); }

   void write_u2(u2 x);

   void write_u4(u4 x);

   void write_u8(u8 x);

   void write_objectID(oop o);

   void write_symbolID(Symbol* o);

   void write_classID(Klass* k);

   void write_id(u4 x);

 };

 DumpWriter::DumpWriter(const char* path) {

   // try to allocate an I/O buffer of io_buffer_size. If there isn't

   // sufficient memory then reduce size until we can allocate something.

   _size = io_buffer_size;

   do {

     _buffer = (char*)os::malloc(_size, mtInternal);

     if (_buffer == NULL) {

       _size = _size >> 1;

     }

   } while (_buffer == NULL && _size > 0);

   assert((_size > 0 && _buffer != NULL) || (_size == 0 && _buffer == NULL), "sanity check");

   _pos = 0;

   _error = NULL;

   _bytes_written = 0L;

   _dump_start = (jlong)-1;

   _fd = os::create_binary_file(path, false);    // don't replace existing file

   // if the open failed we record the error

   if (_fd < 0) {

     _error = (char*)os::strdup(strerror(errno));

   }

 }

 DumpWriter::~DumpWriter() {

   // flush and close dump file

   if (is_open()) {

     close();

   }

   if (_buffer != NULL) os::free(_buffer);

   if (_error != NULL) os::free(_error);

 }

 // closes dump file (if open)

 void DumpWriter::close() {

   // flush and close dump file

   if (is_open()) {

     flush();

     ::close(file_descriptor());

     set_file_descriptor(-1);

   }

 }

 // sets the dump starting position

 void DumpWriter::set_dump_start(jlong pos) {

   _dump_start = pos;

 }

 julong DumpWriter::current_record_length() {

   if (is_open()) {

     // calculate the size of the dump record

     julong dump_end = bytes_written() + bytes_unwritten();

     assert(dump_end == (size_t)current_offset(), "checking");

     julong dump_len = dump_end - dump_start() - 4;

     return dump_len;

   }

   return 0;

 }

 // write directly to the file

 void DumpWriter::write_internal(void* s, size_t len) {

   if (is_open()) {

     const char* pos = (char*)s;

     ssize_t n = 0;

     while (len > 0) {

       uint tmp = (uint)MIN2(len, (size_t)UINT_MAX);

       n = ::write(file_descriptor(), pos, tmp);

       if (n < 0) {

         set_error(strerror(errno));

         ::close(file_descriptor());

         set_file_descriptor(-1);

         return;

       }

       _bytes_written += n;

       pos += n;

       len -= n;

     }

   }

 }

 // write raw bytes

 void DumpWriter::write_raw(void* s, size_t len) {

   if (is_open()) {

     // flush buffer to make room

     if ((position() + len) >= buffer_size()) {

       flush();

     }

     // buffer not available or too big to buffer it

     if ((buffer() == NULL) || (len >= buffer_size())) {

       write_internal(s, len);

     } else {

       // Should optimize this for u1/u2/u4/u8 sizes.

       memcpy(buffer() + position(), s, len);

       set_position(position() + len);

     }

   }

 }

 // flush any buffered bytes to the file

 void DumpWriter::flush() {

   if (is_open() && position() > 0) {

     write_internal(buffer(), position());

     set_position(0);

   }

 }

 jlong DumpWriter::current_offset() {

   if (is_open()) {

     // the offset is the file offset plus whatever we have buffered

     jlong offset = os::current_file_offset(file_descriptor());

     assert(offset >= 0, "lseek failed");

     return offset + position();

   } else {

     return (jlong)-1;

   }

 }

 void DumpWriter::seek_to_offset(jlong off) {

   assert(off >= 0, "bad offset");

   // need to flush before seeking

   flush();

   // may be closed due to I/O error

   if (is_open()) {

     jlong n = os::seek_to_file_offset(file_descriptor(), off);

     assert(n >= 0, "lseek failed");

   }

 }

 void DumpWriter::write_u2(u2 x) {

   u2 v;

   Bytes::put_Java_u2((address)&v, x);

   write_raw((void*)&v, 2);

 }

 void DumpWriter::write_u4(u4 x) {

   u4 v;

   Bytes::put_Java_u4((address)&v, x);

   write_raw((void*)&v, 4);

 }

 void DumpWriter::write_u8(u8 x) {

   u8 v;

   Bytes::put_Java_u8((address)&v, x);

   write_raw((void*)&v, 8);

 }

 void DumpWriter::write_objectID(oop o) {

   address a = (address)o;

 #ifdef _LP64

   write_u8((u8)a);

 #else

   write_u4((u4)a);

 #endif

 }

 void DumpWriter::write_symbolID(Symbol* s) {

   address a = (address)((uintptr_t)s);

 #ifdef _LP64

   write_u8((u8)a);

 #else

   write_u4((u4)a);

 #endif

 }

 void DumpWriter::write_id(u4 x) {

 #ifdef _LP64

   write_u8((u8) x);

 #else

   write_u4(x);

 #endif

 }

 // We use java mirror as the class ID

 void DumpWriter::write_classID(Klass* k) {

   write_objectID(k->java_mirror());

 }

 // Support class with a collection of functions used when dumping the heap

 class DumperSupport : AllStatic {

  public:

   // write a header of the given type

   static void write_header(DumpWriter* writer, hprofTag tag, u4 len);

   // returns hprof tag for the given type signature

   static hprofTag sig2tag(Symbol* sig);

   // returns hprof tag for the given basic type

   static hprofTag type2tag(BasicType type);

   // returns the size of the instance of the given class

   static u4 instance_size(Klass* k);

   // dump a jfloat

   static void dump_float(DumpWriter* writer, jfloat f);

   // dump a jdouble

   static void dump_double(DumpWriter* writer, jdouble d);

   // dumps the raw value of the given field

   static void dump_field_value(DumpWriter* writer, char type, address addr);

   // dumps static fields of the given class

   static void dump_static_fields(DumpWriter* writer, Klass* k);

   // dump the raw values of the instance fields of the given object

   static void dump_instance_fields(DumpWriter* writer, oop o);

   // dumps the definition of the instance fields for a given class

   static void dump_instance_field_descriptors(DumpWriter* writer, Klass* k);

   // creates HPROF_GC_INSTANCE_DUMP record for the given object

   static void dump_instance(DumpWriter* writer, oop o);

   // creates HPROF_GC_CLASS_DUMP record for the given class and each of its

   // array classes

   static void dump_class_and_array_classes(DumpWriter* writer, Klass* k);

   // creates HPROF_GC_CLASS_DUMP record for a given primitive array

   // class (and each multi-dimensional array class too)

   static void dump_basic_type_array_class(DumpWriter* writer, Klass* k);

   // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array

   static void dump_object_array(DumpWriter* writer, objArrayOop array);

   // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array

   static void dump_prim_array(DumpWriter* writer, typeArrayOop array);

   // create HPROF_FRAME record for the given method and bci

   static void dump_stack_frame(DumpWriter* writer, int frame_serial_num, int class_serial_num, Method* m, int bci);

   // check if we need to truncate an array

   static int calculate_array_max_length(DumpWriter* writer, arrayOop array, short header_size);

   // writes a HPROF_HEAP_DUMP_SEGMENT record

   static void write_dump_header(DumpWriter* writer);

   // fixes up the length of the current dump record

   static void write_current_dump_record_length(DumpWriter* writer);

   // fixes up the current dump record and writes HPROF_HEAP_DUMP_END record

   static void end_of_dump(DumpWriter* writer);

 };

 // write a header of the given type

 void DumperSupport:: write_header(DumpWriter* writer, hprofTag tag, u4 len) {

   writer->write_u1((u1)tag);

   writer->write_u4(0);                  // current ticks

   writer->write_u4(len);

 }

 // returns hprof tag for the given type signature

 hprofTag DumperSupport::sig2tag(Symbol* sig) {

   switch (sig->byte_at(0)) {

     case JVM_SIGNATURE_CLASS    : return HPROF_NORMAL_OBJECT;

     case JVM_SIGNATURE_ARRAY    : return HPROF_NORMAL_OBJECT;

     case JVM_SIGNATURE_BYTE     : return HPROF_BYTE;

     case JVM_SIGNATURE_CHAR     : return HPROF_CHAR;

     case JVM_SIGNATURE_FLOAT    : return HPROF_FLOAT;

     case JVM_SIGNATURE_DOUBLE   : return HPROF_DOUBLE;

     case JVM_SIGNATURE_INT      : return HPROF_INT;

     case JVM_SIGNATURE_LONG     : return HPROF_LONG;

     case JVM_SIGNATURE_SHORT    : return HPROF_SHORT;

     case JVM_SIGNATURE_BOOLEAN  : return HPROF_BOOLEAN;

     default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;

   }

 }

 hprofTag DumperSupport::type2tag(BasicType type) {

   switch (type) {

     case T_BYTE     : return HPROF_BYTE;

     case T_CHAR     : return HPROF_CHAR;

     case T_FLOAT    : return HPROF_FLOAT;

     case T_DOUBLE   : return HPROF_DOUBLE;

     case T_INT      : return HPROF_INT;

     case T_LONG     : return HPROF_LONG;

     case T_SHORT    : return HPROF_SHORT;

     case T_BOOLEAN  : return HPROF_BOOLEAN;

     default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;

   }

 }

 // dump a jfloat

 void DumperSupport::dump_float(DumpWriter* writer, jfloat f) {

   if (g_isnan(f)) {

     writer->write_u4(0x7fc00000);    // collapsing NaNs

   } else {

     union {

       int i;

       float f;

     } u;

     u.f = (float)f;

     writer->write_u4((u4)u.i);

   }

 }

 // dump a jdouble

 void DumperSupport::dump_double(DumpWriter* writer, jdouble d) {

   union {

     jlong l;

     double d;

   } u;

   if (g_isnan(d)) {                 // collapsing NaNs

     u.l = (jlong)(0x7ff80000);

     u.l = (u.l << 32);

   } else {

     u.d = (double)d;

   }

   writer->write_u8((u8)u.l);

 }

 // dumps the raw value of the given field

 void DumperSupport::dump_field_value(DumpWriter* writer, char type, address addr) {

   switch (type) {

     case JVM_SIGNATURE_CLASS :

     case JVM_SIGNATURE_ARRAY : {

       oop o;

       if (UseCompressedOops) {

         o = oopDesc::load_decode_heap_oop((narrowOop*)addr);

       } else {

         o = oopDesc::load_decode_heap_oop((oop*)addr);

       }

       // reflection and sun.misc.Unsafe classes may have a reference to a

       // Klass* so filter it out.

       assert(o->is_oop_or_null(), "should always be an oop");

       writer->write_objectID(o);

       break;

     }

     case JVM_SIGNATURE_BYTE     : {

       jbyte* b = (jbyte*)addr;

       writer->write_u1((u1)*b);

       break;

     }

     case JVM_SIGNATURE_CHAR     : {

       jchar* c = (jchar*)addr;

       writer->write_u2((u2)*c);

       break;

     }

     case JVM_SIGNATURE_SHORT : {

       jshort* s = (jshort*)addr;

       writer->write_u2((u2)*s);

       break;

     }

     case JVM_SIGNATURE_FLOAT : {

       jfloat* f = (jfloat*)addr;

       dump_float(writer, *f);

       break;

     }

     case JVM_SIGNATURE_DOUBLE : {

       jdouble* f = (jdouble*)addr;

       dump_double(writer, *f);

       break;

     }

     case JVM_SIGNATURE_INT : {

       jint* i = (jint*)addr;

       writer->write_u4((u4)*i);

       break;

     }

     case JVM_SIGNATURE_LONG     : {

       jlong* l = (jlong*)addr;

       writer->write_u8((u8)*l);

       break;

     }

     case JVM_SIGNATURE_BOOLEAN : {

       jboolean* b = (jboolean*)addr;

       writer->write_u1((u1)*b);

       break;

     }

     default : ShouldNotReachHere();

   }

 }

 // returns the size of the instance of the given class

 u4 DumperSupport::instance_size(Klass* k) {

   HandleMark hm;

   instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), k);

   u4 size = 0;

   for (FieldStream fld(ikh, false, false); !fld.eos(); fld.next()) {

     if (!fld.access_flags().is_static()) {

       Symbol* sig = fld.signature();

       switch (sig->byte_at(0)) {

         case JVM_SIGNATURE_CLASS   :

         case JVM_SIGNATURE_ARRAY   : size += oopSize; break;

         case JVM_SIGNATURE_BYTE    :

         case JVM_SIGNATURE_BOOLEAN : size += 1; break;

         case JVM_SIGNATURE_CHAR    :

         case JVM_SIGNATURE_SHORT   : size += 2; break;

         case JVM_SIGNATURE_INT     :

         case JVM_SIGNATURE_FLOAT   : size += 4; break;

         case JVM_SIGNATURE_LONG    :

         case JVM_SIGNATURE_DOUBLE  : size += 8; break;

         default : ShouldNotReachHere();

       }

     }

   }

   return size;

 }

 // dumps static fields of the given class

 void DumperSupport::dump_static_fields(DumpWriter* writer, Klass* k) {

   HandleMark hm;

   instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), k);

   // pass 1 - count the static fields

   u2 field_count = 0;

   for (FieldStream fldc(ikh, true, true); !fldc.eos(); fldc.next()) {

     if (fldc.access_flags().is_static()) field_count++;

   }

   // Add in resolved_references which is referenced by the cpCache

   // The resolved_references is an array per InstanceKlass holding the

   // strings and other oops resolved from the constant pool.

   oop resolved_references = ikh->constants()->resolved_references_or_null();

   if (resolved_references != NULL) {

     field_count++;

     // Add in the resolved_references of the used previous versions of the class

     // in the case of RedefineClasses

     InstanceKlass* prev = ikh->previous_versions();

     while (prev != NULL && prev->constants()->resolved_references_or_null() != NULL) {

       field_count++;

       prev = prev->previous_versions();

     }

   }

   // Also provide a pointer to the init_lock if present, so there aren't unreferenced int[0]

   // arrays.

   oop init_lock = ikh->init_lock();

   if (init_lock != NULL) {

     field_count++;

   }

   writer->write_u2(field_count);

   // pass 2 - dump the field descriptors and raw values

   for (FieldStream fld(ikh, true, true); !fld.eos(); fld.next()) {

     if (fld.access_flags().is_static()) {

       Symbol* sig = fld.signature();

       writer->write_symbolID(fld.name());   // name

       writer->write_u1(sig2tag(sig));       // type

       // value

       int offset = fld.offset();

       address addr = (address)ikh->java_mirror() + offset;

       dump_field_value(writer, sig->byte_at(0), addr);

     }

   }

   // Add resolved_references for each class that has them

   if (resolved_references != NULL) {

     writer->write_symbolID(vmSymbols::resolved_references_name());  // name

     writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type

     writer->write_objectID(resolved_references);

     // Also write any previous versions

     InstanceKlass* prev = ikh->previous_versions();

     while (prev != NULL && prev->constants()->resolved_references_or_null() != NULL) {

       writer->write_symbolID(vmSymbols::resolved_references_name());  // name

       writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type

       writer->write_objectID(prev->constants()->resolved_references());

       prev = prev->previous_versions();

     }

   }

   // Add init lock to the end if the class is not yet initialized

   if (init_lock != NULL) {

     writer->write_symbolID(vmSymbols::init_lock_name());         // name

     writer->write_u1(sig2tag(vmSymbols::int_array_signature())); // type

     writer->write_objectID(init_lock);

   }

 }

 // dump the raw values of the instance fields of the given object

 void DumperSupport::dump_instance_fields(DumpWriter* writer, oop o) {

   HandleMark hm;

   instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), o->klass());

   for (FieldStream fld(ikh, false, false); !fld.eos(); fld.next()) {

     if (!fld.access_flags().is_static()) {

       Symbol* sig = fld.signature();

       address addr = (address)o + fld.offset();

       dump_field_value(writer, sig->byte_at(0), addr);

     }

   }

 }

 // dumps the definition of the instance fields for a given class

 void DumperSupport::dump_instance_field_descriptors(DumpWriter* writer, Klass* k) {

   HandleMark hm;

   instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), k);

   // pass 1 - count the instance fields

   u2 field_count = 0;

   for (FieldStream fldc(ikh, true, true); !fldc.eos(); fldc.next()) {

     if (!fldc.access_flags().is_static()) field_count++;

   }

   writer->write_u2(field_count);

   // pass 2 - dump the field descriptors

   for (FieldStream fld(ikh, true, true); !fld.eos(); fld.next()) {

     if (!fld.access_flags().is_static()) {

       Symbol* sig = fld.signature();

       writer->write_symbolID(fld.name());   // name

       writer->write_u1(sig2tag(sig));       // type

     }

   }

 }

 // creates HPROF_GC_INSTANCE_DUMP record for the given object

 void DumperSupport::dump_instance(DumpWriter* writer, oop o) {

   Klass* k = o->klass();

   writer->write_u1(HPROF_GC_INSTANCE_DUMP);

   writer->write_objectID(o);

   writer->write_u4(STACK_TRACE_ID);

   // class ID

   writer->write_classID(k);

   // number of bytes that follow

   writer->write_u4(instance_size(k) );

   // field values

   dump_instance_fields(writer, o);

 }

 // creates HPROF_GC_CLASS_DUMP record for the given class and each of

 // its array classes

 void DumperSupport::dump_class_and_array_classes(DumpWriter* writer, Klass* k) {

   Klass* klass = k;

   InstanceKlass* ik = InstanceKlass::cast(k);

   // We can safepoint and do a heap dump at a point where we have a Klass,

   // but no java mirror class has been setup for it. So we need to check

   // that the class is at least loaded, to avoid crash from a null mirror.

   if (!ik->is_loaded()) {

     return;

   }

   writer->write_u1(HPROF_GC_CLASS_DUMP);

   // class ID

   writer->write_classID(ik);

   writer->write_u4(STACK_TRACE_ID);

   // super class ID

   Klass* java_super = ik->java_super();

   if (java_super == NULL) {

     writer->write_objectID(oop(NULL));

   } else {

     writer->write_classID(java_super);

   }

   writer->write_objectID(ik->class_loader());

   writer->write_objectID(ik->signers());

   writer->write_objectID(ik->protection_domain());

   // reserved

   writer->write_objectID(oop(NULL));

   writer->write_objectID(oop(NULL));

   // instance size

   writer->write_u4(DumperSupport::instance_size(k));

   // size of constant pool - ignored by HAT 1.1

   writer->write_u2(0);

   // number of static fields

   dump_static_fields(writer, k);

   // description of instance fields

   dump_instance_field_descriptors(writer, k);

   // array classes

   k = klass->array_klass_or_null();

   while (k != NULL) {

     Klass* klass = k;

     assert(klass->oop_is_objArray(), "not an ObjArrayKlass");

     writer->write_u1(HPROF_GC_CLASS_DUMP);

     writer->write_classID(klass);

     writer->write_u4(STACK_TRACE_ID);

     // super class of array classes is java.lang.Object

     java_super = klass->java_super();

     assert(java_super != NULL, "checking");

     writer->write_classID(java_super);

     writer->write_objectID(ik->class_loader());

     writer->write_objectID(ik->signers());

     writer->write_objectID(ik->protection_domain());

     writer->write_objectID(oop(NULL));    // reserved

     writer->write_objectID(oop(NULL));

     writer->write_u4(0);             // instance size

     writer->write_u2(0);             // constant pool

     writer->write_u2(0);             // static fields

     writer->write_u2(0);             // instance fields

     // get the array class for the next rank

     k = klass->array_klass_or_null();

   }

 }

 // creates HPROF_GC_CLASS_DUMP record for a given primitive array

 // class (and each multi-dimensional array class too)

 void DumperSupport::dump_basic_type_array_class(DumpWriter* writer, Klass* k) {

  // array classes

  while (k != NULL) {

     Klass* klass = k;

     writer->write_u1(HPROF_GC_CLASS_DUMP);

     writer->write_classID(klass);

     writer->write_u4(STACK_TRACE_ID);

     // super class of array classes is java.lang.Object

     Klass* java_super = klass->java_super();

     assert(java_super != NULL, "checking");

     writer->write_classID(java_super);

     writer->write_objectID(oop(NULL));    // loader

     writer->write_objectID(oop(NULL));    // signers

     writer->write_objectID(oop(NULL));    // protection domain

     writer->write_objectID(oop(NULL));    // reserved

     writer->write_objectID(oop(NULL));

     writer->write_u4(0);             // instance size

     writer->write_u2(0);             // constant pool

     writer->write_u2(0);             // static fields

     writer->write_u2(0);             // instance fields

     // get the array class for the next rank

     k = klass->array_klass_or_null();

   }

 }

 // Hprof uses an u4 as record length field,

 // which means we need to truncate arrays that are too long.

 int DumperSupport::calculate_array_max_length(DumpWriter* writer, arrayOop array, short header_size) {

   BasicType type = ArrayKlass::cast(array->klass())->element_type();

   assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type");

   int length = array->length();

   int type_size;

   if (type == T_OBJECT) {

     type_size = sizeof(address);

   } else {

     type_size = type2aelembytes(type);

   }

   size_t length_in_bytes = (size_t)length * type_size;

   // Create a new record if the current record is non-empty and the array can't fit.

   julong current_record_length = writer->current_record_length();

   if (current_record_length > 0 &&

       (current_record_length + header_size + length_in_bytes) > max_juint) {

     write_current_dump_record_length(writer);

     write_dump_header(writer);

     // We now have an empty record.

     current_record_length = 0;

   }

   // Calculate max bytes we can use.

   uint max_bytes = max_juint - (header_size + current_record_length);

   // Array too long for the record?

   // Calculate max length and return it.

   if (length_in_bytes > max_bytes) {

     length = max_bytes / type_size;

     length_in_bytes = (size_t)length * type_size;

     warning("cannot dump array of type %s[] with length %d; truncating to length %d",

             type2name_tab[type], array->length(), length);

   }

   return length;

 }

 // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array

 void DumperSupport::dump_object_array(DumpWriter* writer, objArrayOop array) {

   // sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID) + sizeof(classID)

   short header_size = 1 + 2 * 4 + 2 * sizeof(address);

   int length = calculate_array_max_length(writer, array, header_size);

   writer->write_u1(HPROF_GC_OBJ_ARRAY_DUMP);

   writer->write_objectID(array);

   writer->write_u4(STACK_TRACE_ID);

   writer->write_u4(length);

   // array class ID

   writer->write_classID(array->klass());

   // [id]* elements

   for (int index = 0; index < length; index++) {

     oop o = array->obj_at(index);

     writer->write_objectID(o);

   }

 }

 #define WRITE_ARRAY(Array, Type, Size, Length) \

   for (int i = 0; i < Length; i++) { writer->write_##Size((Size)array->Type##_at(i)); }

 // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array

 void DumperSupport::dump_prim_array(DumpWriter* writer, typeArrayOop array) {

   BasicType type = TypeArrayKlass::cast(array->klass())->element_type();

   // 2 * sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID)

   short header_size = 2 * 1 + 2 * 4 + sizeof(address);

   int length = calculate_array_max_length(writer, array, header_size);

   int type_size = type2aelembytes(type);

   u4 length_in_bytes = (u4)length * type_size;

   writer->write_u1(HPROF_GC_PRIM_ARRAY_DUMP);

   writer->write_objectID(array);

   writer->write_u4(STACK_TRACE_ID);

   writer->write_u4(length);

   writer->write_u1(type2tag(type));

   // nothing to copy

   if (length == 0) {

     return;

   }

   // If the byte ordering is big endian then we can copy most types directly

   switch (type) {

     case T_INT : {

       if (Bytes::is_Java_byte_ordering_different()) {

         WRITE_ARRAY(array, int, u4, length);

       } else {

         writer->write_raw((void*)(array->int_at_addr(0)), length_in_bytes);

       }

       break;

     }

     case T_BYTE : {

       writer->write_raw((void*)(array->byte_at_addr(0)), length_in_bytes);

       break;

     }

     case T_CHAR : {

       if (Bytes::is_Java_byte_ordering_different()) {

         WRITE_ARRAY(array, char, u2, length);

       } else {

         writer->write_raw((void*)(array->char_at_addr(0)), length_in_bytes);

       }

       break;

     }

     case T_SHORT : {

       if (Bytes::is_Java_byte_ordering_different()) {

         WRITE_ARRAY(array, short, u2, length);

       } else {

         writer->write_raw((void*)(array->short_at_addr(0)), length_in_bytes);

       }

       break;

     }

     case T_BOOLEAN : {

       if (Bytes::is_Java_byte_ordering_different()) {

         WRITE_ARRAY(array, bool, u1, length);

       } else {

         writer->write_raw((void*)(array->bool_at_addr(0)), length_in_bytes);

       }

       break;

     }

     case T_LONG : {

       if (Bytes::is_Java_byte_ordering_different()) {

         WRITE_ARRAY(array, long, u8, length);

       } else {

         writer->write_raw((void*)(array->long_at_addr(0)), length_in_bytes);

       }

       break;

     }

     // handle float/doubles in a special value to ensure than NaNs are

     // written correctly. TO DO: Check if we can avoid this on processors that

     // use IEEE 754.

     case T_FLOAT : {

       for (int i = 0; i < length; i++) {

         dump_float(writer, array->float_at(i));

       }

       break;

     }

     case T_DOUBLE : {

       for (int i = 0; i < length; i++) {

         dump_double(writer, array->double_at(i));

       }

       break;

     }

     default : ShouldNotReachHere();

   }

 }

 // create a HPROF_FRAME record of the given Method* and bci

 void DumperSupport::dump_stack_frame(DumpWriter* writer,

                                      int frame_serial_num,

                                      int class_serial_num,

                                      Method* m,

                                      int bci) {

   int line_number;

   if (m->is_native()) {

     line_number = -3;  // native frame

   } else {

     line_number = m->line_number_from_bci(bci);

   }

   write_header(writer, HPROF_FRAME, 4*oopSize + 2*sizeof(u4));

   writer->write_id(frame_serial_num);               // frame serial number

   writer->write_symbolID(m->name());                // method's name

   writer->write_symbolID(m->signature());           // method's signature

   assert(m->method_holder()->oop_is_instance(), "not InstanceKlass");

   writer->write_symbolID(m->method_holder()->source_file_name());  // source file name

   writer->write_u4(class_serial_num);               // class serial number

   writer->write_u4((u4) line_number);               // line number

 }

 // Support class used to generate HPROF_UTF8 records from the entries in the

 // SymbolTable.

 class SymbolTableDumper : public SymbolClosure {

  private:

   DumpWriter* _writer;

   DumpWriter* writer() const                { return _writer; }

  public:

   SymbolTableDumper(DumpWriter* writer)     { _writer = writer; }

   void do_symbol(Symbol** p);

 };

 void SymbolTableDumper::do_symbol(Symbol** p) {

   ResourceMark rm;

   Symbol* sym = load_symbol(p);

   int len = sym->utf8_length();

   if (len > 0) {

     char* s = sym->as_utf8();

     DumperSupport::write_header(writer(), HPROF_UTF8, oopSize + len);

     writer()->write_symbolID(sym);

     writer()->write_raw(s, len);

   }

 }

 // Support class used to generate HPROF_GC_ROOT_JNI_LOCAL records

 class JNILocalsDumper : public OopClosure {

  private:

   DumpWriter* _writer;

   u4 _thread_serial_num;

   int _frame_num;

   DumpWriter* writer() const                { return _writer; }

  public:

   JNILocalsDumper(DumpWriter* writer, u4 thread_serial_num) {

     _writer = writer;

     _thread_serial_num = thread_serial_num;

     _frame_num = -1;  // default - empty stack

   }

   void set_frame_number(int n) { _frame_num = n; }

   void do_oop(oop* obj_p);

   void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }

 };

 void JNILocalsDumper::do_oop(oop* obj_p) {

   // ignore null or deleted handles

   oop o = *obj_p;

   if (o != NULL && o != JNIHandles::deleted_handle()) {

     writer()->write_u1(HPROF_GC_ROOT_JNI_LOCAL);

     writer()->write_objectID(o);

     writer()->write_u4(_thread_serial_num);

     writer()->write_u4((u4)_frame_num);

   }

 }

 // Support class used to generate HPROF_GC_ROOT_JNI_GLOBAL records

 class JNIGlobalsDumper : public OopClosure {

  private:

   DumpWriter* _writer;

   DumpWriter* writer() const                { return _writer; }

  public:

   JNIGlobalsDumper(DumpWriter* writer) {

     _writer = writer;

   }

   void do_oop(oop* obj_p);

   void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }

 };

 void JNIGlobalsDumper::do_oop(oop* obj_p) {

   oop o = *obj_p;

   // ignore these

   if (o == NULL || o == JNIHandles::deleted_handle()) return;

   // we ignore global ref to symbols and other internal objects

   if (o->is_instance() || o->is_objArray() || o->is_typeArray()) {

     writer()->write_u1(HPROF_GC_ROOT_JNI_GLOBAL);

     writer()->write_objectID(o);

     writer()->write_objectID((oopDesc*)obj_p);      // global ref ID

   }

 };

 // Support class used to generate HPROF_GC_ROOT_MONITOR_USED records

 class MonitorUsedDumper : public OopClosure {

  private:

   DumpWriter* _writer;

   DumpWriter* writer() const                { return _writer; }

  public:

   MonitorUsedDumper(DumpWriter* writer) {

     _writer = writer;

   }

   void do_oop(oop* obj_p) {

     writer()->write_u1(HPROF_GC_ROOT_MONITOR_USED);

     writer()->write_objectID(*obj_p);

   }

   void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }

 };

 // Support class used to generate HPROF_GC_ROOT_STICKY_CLASS records

 class StickyClassDumper : public KlassClosure {

  private:

   DumpWriter* _writer;

   DumpWriter* writer() const                { return _writer; }

  public:

   StickyClassDumper(DumpWriter* writer) {

     _writer = writer;

   }

   void do_klass(Klass* k) {

     if (k->oop_is_instance()) {

       InstanceKlass* ik = InstanceKlass::cast(k);

         writer()->write_u1(HPROF_GC_ROOT_STICKY_CLASS);

         writer()->write_classID(ik);

       }

     }

 };

 class VM_HeapDumper;

 // Support class using when iterating over the heap.

 class HeapObjectDumper : public ObjectClosure {

  private:

   VM_HeapDumper* _dumper;

   DumpWriter* _writer;

   VM_HeapDumper* dumper()               { return _dumper; }

   DumpWriter* writer()                  { return _writer; }

   // used to indicate that a record has been writen

   void mark_end_of_record();

  public:

   HeapObjectDumper(VM_HeapDumper* dumper, DumpWriter* writer) {

     _dumper = dumper;

     _writer = writer;

   }

   // called for each object in the heap

   void do_object(oop o);

 };

 void HeapObjectDumper::do_object(oop o) {

   // hide the sentinel for deleted handles

   if (o == JNIHandles::deleted_handle()) return;

   // skip classes as these emitted as HPROF_GC_CLASS_DUMP records

   if (o->klass() == SystemDictionary::Class_klass()) {

     if (!java_lang_Class::is_primitive(o)) {

       return;

     }

   }

   if (o->is_instance()) {

     // create a HPROF_GC_INSTANCE record for each object

     DumperSupport::dump_instance(writer(), o);

     mark_end_of_record();

   } else if (o->is_objArray()) {

     // create a HPROF_GC_OBJ_ARRAY_DUMP record for each object array

     DumperSupport::dump_object_array(writer(), objArrayOop(o));

     mark_end_of_record();

   } else if (o->is_typeArray()) {

     // create a HPROF_GC_PRIM_ARRAY_DUMP record for each type array

     DumperSupport::dump_prim_array(writer(), typeArrayOop(o));

     mark_end_of_record();

   }

 }

 // The VM operation that performs the heap dump

 class VM_HeapDumper : public VM_GC_Operation {

  private:

   static VM_HeapDumper* _global_dumper;

   static DumpWriter*    _global_writer;

   DumpWriter*           _local_writer;

   JavaThread*           _oome_thread;

   Method*               _oome_constructor;

   bool _gc_before_heap_dump;

   GrowableArray<Klass*>* _klass_map;

   ThreadStackTrace** _stack_traces;

   int _num_threads;

   // accessors and setters

   static VM_HeapDumper* dumper()         {  assert(_global_dumper != NULL, "Error"); return _global_dumper; }

   static DumpWriter* writer()            {  assert(_global_writer != NULL, "Error"); return _global_writer; }

   void set_global_dumper() {

     assert(_global_dumper == NULL, "Error");

     _global_dumper = this;

   }

   void set_global_writer() {

     assert(_global_writer == NULL, "Error");

     _global_writer = _local_writer;

   }

   void clear_global_dumper() { _global_dumper = NULL; }

   void clear_global_writer() { _global_writer = NULL; }

   bool skip_operation() const;

   // writes a HPROF_LOAD_CLASS record

   static void do_load_class(Klass* k);

   // writes a HPROF_GC_CLASS_DUMP record for the given class

   // (and each array class too)

   static void do_class_dump(Klass* k);

   // writes a HPROF_GC_CLASS_DUMP records for a given basic type

   // array (and each multi-dimensional array too)

   static void do_basic_type_array_class_dump(Klass* k);

   // HPROF_GC_ROOT_THREAD_OBJ records

   int do_thread(JavaThread* thread, u4 thread_serial_num);

   void do_threads();

   void add_class_serial_number(Klass* k, int serial_num) {

     _klass_map->at_put_grow(serial_num, k);

   }

   // HPROF_TRACE and HPROF_FRAME records

   void dump_stack_traces();

  public:

   VM_HeapDumper(DumpWriter* writer, bool gc_before_heap_dump, bool oome) :

     VM_GC_Operation(0 /* total collections,      dummy, ignored */,

                     GCCause::_heap_dump /* GC Cause */,

                     0 /* total full collections, dummy, ignored */,

                     gc_before_heap_dump) {

     _local_writer = writer;

     _gc_before_heap_dump = gc_before_heap_dump;

     _klass_map = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<Klass*>(INITIAL_CLASS_COUNT, true);

     _stack_traces = NULL;

     _num_threads = 0;

     if (oome) {

       assert(!Thread::current()->is_VM_thread(), "Dump from OutOfMemoryError cannot be called by the VMThread");

       // get OutOfMemoryError zero-parameter constructor

       InstanceKlass* oome_ik = InstanceKlass::cast(SystemDictionary::OutOfMemoryError_klass());

       _oome_constructor = oome_ik->find_method(vmSymbols::object_initializer_name(),

                                                           vmSymbols::void_method_signature());

       // get thread throwing OOME when generating the heap dump at OOME

       _oome_thread = JavaThread::current();

     } else {

       _oome_thread = NULL;

       _oome_constructor = NULL;

     }

   }

   ~VM_HeapDumper() {

     if (_stack_traces != NULL) {

       for (int i=0; i < _num_threads; i++) {

         delete _stack_traces[i];

       }

       FREE_C_HEAP_ARRAY(ThreadStackTrace*, _stack_traces, mtInternal);

     }

     delete _klass_map;

   }

   VMOp_Type type() const { return VMOp_HeapDumper; }

   // used to mark sub-record boundary

   void check_segment_length();

   void doit();

 };

 VM_HeapDumper* VM_HeapDumper::_global_dumper = NULL;

 DumpWriter*    VM_HeapDumper::_global_writer = NULL;

 bool VM_HeapDumper::skip_operation() const {

   return false;

 }

  // writes a HPROF_HEAP_DUMP_SEGMENT record

 void DumperSupport::write_dump_header(DumpWriter* writer) {

   if (writer->is_open()) {

     writer->write_u1(HPROF_HEAP_DUMP_SEGMENT);

     writer->write_u4(0); // current ticks

     // record the starting position for the dump (its length will be fixed up later)

     writer->set_dump_start(writer->current_offset());

     writer->write_u4(0);

   }

 }

 // fixes up the length of the current dump record

 void DumperSupport::write_current_dump_record_length(DumpWriter* writer) {

   if (writer->is_open()) {

     julong dump_end = writer->bytes_written() + writer->bytes_unwritten();

     julong dump_len = writer->current_record_length();

     // record length must fit in a u4

     if (dump_len > max_juint) {

       warning("record is too large");

     }

     // seek to the dump start and fix-up the length

     assert(writer->dump_start() >= 0, "no dump start recorded");

     writer->seek_to_offset(writer->dump_start());

     writer->write_u4((u4)dump_len);

     // adjust the total size written to keep the bytes written correct.

     writer->adjust_bytes_written(-((jlong) sizeof(u4)));

     // seek to dump end so we can continue

     writer->seek_to_offset(dump_end);

     // no current dump record

     writer->set_dump_start((jlong)-1);

   }

 }

 // used on a sub-record boundary to check if we need to start a

 // new segment.

 void VM_HeapDumper::check_segment_length() {

   if (writer()->is_open()) {

     julong dump_len = writer()->current_record_length();

     if (dump_len > 2UL*G) {

       DumperSupport::write_current_dump_record_length(writer());

       DumperSupport::write_dump_header(writer());

     }

   }

 }

 // fixes up the current dump record and writes HPROF_HEAP_DUMP_END record

 void DumperSupport::end_of_dump(DumpWriter* writer) {

   if (writer->is_open()) {

     write_current_dump_record_length(writer);

     writer->write_u1(HPROF_HEAP_DUMP_END);

     writer->write_u4(0);

     writer->write_u4(0);

   }

 }

 // marks sub-record boundary

 void HeapObjectDumper::mark_end_of_record() {

   dumper()->check_segment_length();

 }

 // writes a HPROF_LOAD_CLASS record for the class (and each of its

 // array classes)

 void VM_HeapDumper::do_load_class(Klass* k) {

   static u4 class_serial_num = 0;

   // len of HPROF_LOAD_CLASS record

   u4 remaining = 2*oopSize + 2*sizeof(u4);

   // write a HPROF_LOAD_CLASS for the class and each array class

   do {

     DumperSupport::write_header(writer(), HPROF_LOAD_CLASS, remaining);

     // class serial number is just a number

     writer()->write_u4(++class_serial_num);

     // class ID

     Klass* klass = k;

     writer()->write_classID(klass);

     // add the Klass* and class serial number pair

     dumper()->add_class_serial_number(klass, class_serial_num);

     writer()->write_u4(STACK_TRACE_ID);

     // class name ID

     Symbol* name = klass->name();

     writer()->write_symbolID(name);

     // write a LOAD_CLASS record for the array type (if it exists)

     k = klass->array_klass_or_null();

   } while (k != NULL);

 }

 // writes a HPROF_GC_CLASS_DUMP record for the given class

 void VM_HeapDumper::do_class_dump(Klass* k) {

   if (k->oop_is_instance()) {

     DumperSupport::dump_class_and_array_classes(writer(), k);

   }

 }

 // writes a HPROF_GC_CLASS_DUMP records for a given basic type

 // array (and each multi-dimensional array too)

 void VM_HeapDumper::do_basic_type_array_class_dump(Klass* k) {

   DumperSupport::dump_basic_type_array_class(writer(), k);

 }

 // Walk the stack of the given thread.

 // Dumps a HPROF_GC_ROOT_JAVA_FRAME record for each local

 // Dumps a HPROF_GC_ROOT_JNI_LOCAL record for each JNI local

 //

 // It returns the number of Java frames in this thread stack

 int VM_HeapDumper::do_thread(JavaThread* java_thread, u4 thread_serial_num) {

   JNILocalsDumper blk(writer(), thread_serial_num);

   oop threadObj = java_thread->threadObj();

   assert(threadObj != NULL, "sanity check");

   int stack_depth = 0;

   if (java_thread->has_last_Java_frame()) {

     // vframes are resource allocated

     Thread* current_thread = Thread::current();

     ResourceMark rm(current_thread);

     HandleMark hm(current_thread);

     RegisterMap reg_map(java_thread);

     frame f = java_thread->last_frame();

     vframe* vf = vframe::new_vframe(&f, &reg_map, java_thread);

     frame* last_entry_frame = NULL;

     int extra_frames = 0;

     if (java_thread == _oome_thread && _oome_constructor != NULL) {

       extra_frames++;

     }

     while (vf != NULL) {

       blk.set_frame_number(stack_depth);

       if (vf->is_java_frame()) {

         // java frame (interpreted, compiled, ...)

         javaVFrame *jvf = javaVFrame::cast(vf);

         if (!(jvf->method()->is_native())) {

           StackValueCollection* locals = jvf->locals();

           for (int slot=0; slot<locals->size(); slot++) {

             if (locals->at(slot)->type() == T_OBJECT) {

               oop o = locals->obj_at(slot)();

               if (o != NULL) {

                 writer()->write_u1(HPROF_GC_ROOT_JAVA_FRAME);

                 writer()->write_objectID(o);

                 writer()->write_u4(thread_serial_num);

                 writer()->write_u4((u4) (stack_depth + extra_frames));

               }

             }

           }

         } else {

           // native frame

           if (stack_depth == 0) {

             // JNI locals for the top frame.

             java_thread->active_handles()->oops_do(&blk);

           } else {

             if (last_entry_frame != NULL) {

               // JNI locals for the entry frame

               assert(last_entry_frame->is_entry_frame(), "checking");

               last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(&blk);

             }

           }

         }

         // increment only for Java frames

         stack_depth++;

         last_entry_frame = NULL;

       } else {

         // externalVFrame - if it's an entry frame then report any JNI locals

         // as roots when we find the corresponding native javaVFrame

         frame* fr = vf->frame_pointer();

         assert(fr != NULL, "sanity check");

         if (fr->is_entry_frame()) {

           last_entry_frame = fr;

         }

       }

       vf = vf->sender();

     }

   } else {

     // no last java frame but there may be JNI locals

     java_thread->active_handles()->oops_do(&blk);

   }

   return stack_depth;

 }

 // write a HPROF_GC_ROOT_THREAD_OBJ record for each java thread. Then walk

 // the stack so that locals and JNI locals are dumped.

 void VM_HeapDumper::do_threads() {

   for (int i=0; i < _num_threads; i++) {

     JavaThread* thread = _stack_traces[i]->thread();

     oop threadObj = thread->threadObj();

     u4 thread_serial_num = i+1;

     u4 stack_serial_num = thread_serial_num + STACK_TRACE_ID;

     writer()->write_u1(HPROF_GC_ROOT_THREAD_OBJ);

     writer()->write_objectID(threadObj);

     writer()->write_u4(thread_serial_num);  // thread number

     writer()->write_u4(stack_serial_num);   // stack trace serial number

     int num_frames = do_thread(thread, thread_serial_num);

     assert(num_frames == _stack_traces[i]->get_stack_depth(),

            "total number of Java frames not matched");

   }

 }

 // The VM operation that dumps the heap. The dump consists of the following

 // records:

 //

 //  HPROF_HEADER

 //  [HPROF_UTF8]*

 //  [HPROF_LOAD_CLASS]*

 //  [[HPROF_FRAME]*|HPROF_TRACE]*

 //  [HPROF_GC_CLASS_DUMP]*

 //  [HPROF_HEAP_DUMP_SEGMENT]*

 //  HPROF_HEAP_DUMP_END

 //

 // The HPROF_TRACE records represent the stack traces where the heap dump

 // is generated and a "dummy trace" record which does not include

 // any frames. The dummy trace record is used to be referenced as the

 // unknown object alloc site.

 //

 // Each HPROF_HEAP_DUMP_SEGMENT record has a length followed by sub-records.

 // To allow the heap dump be generated in a single pass we remember the position

 // of the dump length and fix it up after all sub-records have been written.

 // To generate the sub-records we iterate over the heap, writing

 // HPROF_GC_INSTANCE_DUMP, HPROF_GC_OBJ_ARRAY_DUMP, and HPROF_GC_PRIM_ARRAY_DUMP

 // records as we go. Once that is done we write records for some of the GC

 // roots.

 void VM_HeapDumper::doit() {

   HandleMark hm;

   CollectedHeap* ch = Universe::heap();

   ch->ensure_parsability(false); // must happen, even if collection does

                                  // not happen (e.g. due to GC_locker)

   if (_gc_before_heap_dump) {

     if (GC_locker::is_active()) {

       warning("GC locker is held; pre-heapdump GC was skipped");

     } else {

       ch->collect_as_vm_thread(GCCause::_heap_dump);

     }

   }

   // At this point we should be the only dumper active, so

   // the following should be safe.

   set_global_dumper();

   set_global_writer();

   // Write the file header - we always use 1.0.2

   size_t used = ch->used();

   const char* header = "JAVA PROFILE 1.0.2";

   // header is few bytes long - no chance to overflow int

   writer()->write_raw((void*)header, (int)strlen(header));

   writer()->write_u1(0); // terminator

   writer()->write_u4(oopSize);

   writer()->write_u8(os::javaTimeMillis());

   // HPROF_UTF8 records

   SymbolTableDumper sym_dumper(writer());

   SymbolTable::symbols_do(&sym_dumper);

   // write HPROF_LOAD_CLASS records

   ClassLoaderDataGraph::classes_do(&do_load_class);

   Universe::basic_type_classes_do(&do_load_class);

   // write HPROF_FRAME and HPROF_TRACE records

   // this must be called after _klass_map is built when iterating the classes above.

   dump_stack_traces();

   // write HPROF_HEAP_DUMP_SEGMENT

   DumperSupport::write_dump_header(writer());

   // Writes HPROF_GC_CLASS_DUMP records

   ClassLoaderDataGraph::classes_do(&do_class_dump);

   Universe::basic_type_classes_do(&do_basic_type_array_class_dump);

   check_segment_length();

   // writes HPROF_GC_INSTANCE_DUMP records.

   // After each sub-record is written check_segment_length will be invoked

   // to check if the current segment exceeds a threshold. If so, a new

   // segment is started.

   // The HPROF_GC_CLASS_DUMP and HPROF_GC_INSTANCE_DUMP are the vast bulk

   // of the heap dump.

   HeapObjectDumper obj_dumper(this, writer());

   Universe::heap()->safe_object_iterate(&obj_dumper);

   // HPROF_GC_ROOT_THREAD_OBJ + frames + jni locals

   do_threads();

   check_segment_length();

   // HPROF_GC_ROOT_MONITOR_USED

   MonitorUsedDumper mon_dumper(writer());

   ObjectSynchronizer::oops_do(&mon_dumper);

   check_segment_length();

   // HPROF_GC_ROOT_JNI_GLOBAL

   JNIGlobalsDumper jni_dumper(writer());

   JNIHandles::oops_do(&jni_dumper);

   Universe::oops_do(&jni_dumper);  // technically not jni roots, but global roots

                                    // for things like preallocated throwable backtraces

   check_segment_length();

   // HPROF_GC_ROOT_STICKY_CLASS

   StickyClassDumper class_dumper(writer());

   SystemDictionary::always_strong_classes_do(&class_dumper);

   // fixes up the length of the dump record and writes the HPROF_HEAP_DUMP_END record.

   DumperSupport::end_of_dump(writer());

   // Now we clear the global variables, so that a future dumper might run.

   clear_global_dumper();

   clear_global_writer();

 }

 void VM_HeapDumper::dump_stack_traces() {

   // write a HPROF_TRACE record without any frames to be referenced as object alloc sites

   DumperSupport::write_header(writer(), HPROF_TRACE, 3*sizeof(u4));

   writer()->write_u4((u4) STACK_TRACE_ID);

   writer()->write_u4(0);                    // thread number

   writer()->write_u4(0);                    // frame count

   _stack_traces = NEW_C_HEAP_ARRAY(ThreadStackTrace*, Threads::number_of_threads(), mtInternal);

   int frame_serial_num = 0;

   for (JavaThread* thread = Threads::first(); thread != NULL ; thread = thread->next()) {

     oop threadObj = thread->threadObj();

     if (threadObj != NULL && !thread->is_exiting() && !thread->is_hidden_from_external_view()) {

       // dump thread stack trace

       ThreadStackTrace* stack_trace = new ThreadStackTrace(thread, false);

       stack_trace->dump_stack_at_safepoint(-1);

       _stack_traces[_num_threads++] = stack_trace;

       // write HPROF_FRAME records for this thread's stack trace

       int depth = stack_trace->get_stack_depth();

       int thread_frame_start = frame_serial_num;

       int extra_frames = 0;

       // write fake frame that makes it look like the thread, which caused OOME,

       // is in the OutOfMemoryError zero-parameter constructor

       if (thread == _oome_thread && _oome_constructor != NULL) {

         int oome_serial_num = _klass_map->find(_oome_constructor->method_holder());

         // the class serial number starts from 1

         assert(oome_serial_num > 0, "OutOfMemoryError class not found");

         DumperSupport::dump_stack_frame(writer(), ++frame_serial_num, oome_serial_num,

                                         _oome_constructor, 0);

         extra_frames++;

       }

       for (int j=0; j < depth; j++) {

         StackFrameInfo* frame = stack_trace->stack_frame_at(j);

         Method* m = frame->method();

         int class_serial_num = _klass_map->find(m->method_holder());

         // the class serial number starts from 1

         assert(class_serial_num > 0, "class not found");

         DumperSupport::dump_stack_frame(writer(), ++frame_serial_num, class_serial_num, m, frame->bci());

       }

       depth += extra_frames;

       // write HPROF_TRACE record for one thread

       DumperSupport::write_header(writer(), HPROF_TRACE, 3*sizeof(u4) + depth*oopSize);

       int stack_serial_num = _num_threads + STACK_TRACE_ID;

       writer()->write_u4(stack_serial_num);      // stack trace serial number

       writer()->write_u4((u4) _num_threads);     // thread serial number

       writer()->write_u4(depth);                 // frame count

       for (int j=1; j <= depth; j++) {

         writer()->write_id(thread_frame_start + j);

       }

     }

   }

 }

 // dump the heap to given path.

 PRAGMA_FORMAT_NONLITERAL_IGNORED_EXTERNAL

 int HeapDumper::dump(const char* path) {

   assert(path != NULL && strlen(path) > 0, "path missing");

   // print message in interactive case

   if (print_to_tty()) {

     tty->print_cr("Dumping heap to %s ...", path);

     timer()->start();

   }

   // create the dump writer. If the file can be opened then bail

   DumpWriter writer(path);

   if (!writer.is_open()) {

     set_error(writer.error());

     if (print_to_tty()) {

       tty->print_cr("Unable to create %s: %s", path,

         (error() != NULL) ? error() : "reason unknown");

     }

     return -1;

   }

   // generate the dump

   VM_HeapDumper dumper(&writer, _gc_before_heap_dump, _oome);

   if (Thread::current()->is_VM_thread()) {

     assert(SafepointSynchronize::is_at_safepoint(), "Expected to be called at a safepoint");

     dumper.doit();

   } else {

     VMThread::execute(&dumper);

   }

   // close dump file and record any error that the writer may have encountered

   writer.close();

   set_error(writer.error());

   // print message in interactive case

   if (print_to_tty()) {

     timer()->stop();

     if (error() == NULL) {

       tty->print_cr("Heap dump file created [" JULONG_FORMAT " bytes in %3.3f secs]",

                     writer.bytes_written(), timer()->seconds());

     } else {

       tty->print_cr("Dump file is incomplete: %s", writer.error());

     }

   }

   return (writer.error() == NULL) ? 0 : -1;

 }

 // stop timer (if still active), and free any error string we might be holding

 HeapDumper::~HeapDumper() {

   if (timer()->is_active()) {

     timer()->stop();

   }

   set_error(NULL);

 }

 // returns the error string (resource allocated), or NULL

 char* HeapDumper::error_as_C_string() const {

   if (error() != NULL) {

     char* str = NEW_RESOURCE_ARRAY(char, strlen(error())+1);

     strcpy(str, error());

     return str;

   } else {

     return NULL;

   }

 }

 // set the error string

 void HeapDumper::set_error(char* error) {

   if (_error != NULL) {

     os::free(_error);

   }

   if (error == NULL) {

     _error = NULL;

   } else {

     _error = os::strdup(error);

     assert(_error != NULL, "allocation failure");

   }

 }

 // Called by out-of-memory error reporting by a single Java thread

 // outside of a JVM safepoint

 void HeapDumper::dump_heap_from_oome() {

   HeapDumper::dump_heap(true);

 }

 // Called by error reporting by a single Java thread outside of a JVM safepoint,

 // or by heap dumping by the VM thread during a (GC) safepoint. Thus, these various

 // callers are strictly serialized and guaranteed not to interfere below. For more

 // general use, however, this method will need modification to prevent

 // inteference when updating the static variables base_path and dump_file_seq below.

 void HeapDumper::dump_heap() {

   HeapDumper::dump_heap(false);

 }

 void HeapDumper::dump_heap(bool oome) {

   static char base_path[JVM_MAXPATHLEN] = {'\0'};

   static uint dump_file_seq = 0;

   char* my_path;

   const int max_digit_chars = 20;

   const char* dump_file_name = "java_pid";

   const char* dump_file_ext  = ".hprof";

   // The dump file defaults to java_pid<pid>.hprof in the current working

   // directory. HeapDumpPath=<file> can be used to specify an alternative

   // dump file name or a directory where dump file is created.

   if (dump_file_seq == 0) { // first time in, we initialize base_path

     // Calculate potentially longest base path and check if we have enough

     // allocated statically.

     const size_t total_length =

                       (HeapDumpPath == NULL ? 0 : strlen(HeapDumpPath)) +

                       strlen(os::file_separator()) + max_digit_chars +

                       strlen(dump_file_name) + strlen(dump_file_ext) + 1;

     if (total_length > sizeof(base_path)) {

       warning("Cannot create heap dump file.  HeapDumpPath is too long.");

       return;

     }

     bool use_default_filename = true;

     if (HeapDumpPath == NULL || HeapDumpPath[0] == '\0') {

       // HeapDumpPath=<file> not specified

     } else {

       strncpy(base_path, HeapDumpPath, sizeof(base_path));

       // check if the path is a directory (must exist)

       DIR* dir = os::opendir(base_path);

       if (dir == NULL) {

         use_default_filename = false;

       } else {

         // HeapDumpPath specified a directory. We append a file separator

         // (if needed).

         os::closedir(dir);

         size_t fs_len = strlen(os::file_separator());

         if (strlen(base_path) >= fs_len) {

           char* end = base_path;

           end += (strlen(base_path) - fs_len);

           if (strcmp(end, os::file_separator()) != 0) {

             strcat(base_path, os::file_separator());

           }

         }

       }

     }

     // If HeapDumpPath wasn't a file name then we append the default name

     if (use_default_filename) {

       const size_t dlen = strlen(base_path);  // if heap dump dir specified

       jio_snprintf(&base_path[dlen], sizeof(base_path)-dlen, "%s%d%s",

                    dump_file_name, os::current_process_id(), dump_file_ext);

     }

     const size_t len = strlen(base_path) + 1;

     my_path = (char*)os::malloc(len, mtInternal);

     if (my_path == NULL) {

       warning("Cannot create heap dump file.  Out of system memory.");

       return;

     }

     strncpy(my_path, base_path, len);

   } else {

     // Append a sequence number id for dumps following the first

     const size_t len = strlen(base_path) + max_digit_chars + 2; // for '.' and \0

     my_path = (char*)os::malloc(len, mtInternal);

     if (my_path == NULL) {

       warning("Cannot create heap dump file.  Out of system memory.");

       return;

     }

     jio_snprintf(my_path, len, "%s.%d", base_path, dump_file_seq);

   }

   dump_file_seq++;   // increment seq number for next time we dump

   HeapDumper dumper(false /* no GC before heap dump */,

                     true  /* send to tty */,

                     oome  /* pass along out-of-memory-error flag */);

   dumper.dump(my_path);

   os::free(my_path);

 }