Java example source code file (heapDumper.cpp)
The heapDumper.cpp Java example source code/*
* Copyright (c) 2005, 2013, 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 1.0.1" or "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)
jlong _bytes_written; // number of byte written to dump file
char* _buffer; // internal buffer
int _size;
int _pos;
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; }
int buffer_size() const { return _size; }
int position() const { return _pos; }
void set_position(int 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, int len);
public:
DumpWriter(const char* path);
~DumpWriter();
void close();
bool is_open() const { return file_descriptor() >= 0; }
void flush();
// total number of bytes written to the disk
jlong 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
jlong bytes_unwritten() const { return (jlong)position(); }
char* error() const { return _error; }
jlong current_offset();
void seek_to_offset(jlong pos);
// writer functions
void write_raw(void* s, int 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;
_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);
}
}
// write directly to the file
void DumpWriter::write_internal(void* s, int len) {
if (is_open()) {
int n = ::write(file_descriptor(), s, len);
if (n > 0) {
_bytes_written += n;
}
if (n != len) {
if (n < 0) {
set_error(strerror(errno));
} else {
set_error("file size limit");
}
::close(file_descriptor());
set_file_descriptor(-1);
}
}
}
// write raw bytes
void DumpWriter::write_raw(void* s, int len) {
if (is_open()) {
// flush buffer to make toom
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 + (jlong)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);
};
// 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);
int 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 (u4)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++;
}
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);
}
}
}
// 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;
assert(klass->oop_is_instance(), "not an InstanceKlass");
InstanceKlass* ik = (InstanceKlass*)klass;
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();
}
}
// creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
void DumperSupport::dump_object_array(DumpWriter* writer, objArrayOop array) {
writer->write_u1(HPROF_GC_OBJ_ARRAY_DUMP);
writer->write_objectID(array);
writer->write_u4(STACK_TRACE_ID);
writer->write_u4((u4)array->length());
// array class ID
writer->write_classID(array->klass());
// [id]* elements
for (int index=0; index<array->length(); index++) {
oop o = array->obj_at(index);
writer->write_objectID(o);
}
}
#define WRITE_ARRAY(Array, Type, Size) \
for (int i=0; i<Array->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();
writer->write_u1(HPROF_GC_PRIM_ARRAY_DUMP);
writer->write_objectID(array);
writer->write_u4(STACK_TRACE_ID);
writer->write_u4((u4)array->length());
writer->write_u1(type2tag(type));
// nothing to copy
if (array->length() == 0) {
return;
}
// If the byte ordering is big endian then we can copy most types directly
int length_in_bytes = array->length() * type2aelembytes(type);
assert(length_in_bytes > 0, "nothing to copy");
switch (type) {
case T_INT : {
if (Bytes::is_Java_byte_ordering_different()) {
WRITE_ARRAY(array, int, u4);
} 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);
} 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);
} 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);
} 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);
} 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<array->length(); i++) {
dump_float( writer, array->float_at(i) );
}
break;
}
case T_DOUBLE : {
for (int i=0; i<array->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;
}
}
// create a HPROF_GC_INSTANCE record for each object
if (o->is_instance()) {
DumperSupport::dump_instance(writer(), o);
mark_end_of_record();
} else {
// create a HPROF_GC_OBJ_ARRAY_DUMP record for each object array
if (o->is_objArray()) {
DumperSupport::dump_object_array(writer(), objArrayOop(o));
mark_end_of_record();
} else {
// create a HPROF_GC_PRIM_ARRAY_DUMP record for each type array
if (o->is_typeArray()) {
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;
bool _is_segmented_dump;
jlong _dump_start;
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 is_segmented_dump() const { return _is_segmented_dump; }
void set_segmented_dump() { _is_segmented_dump = true; }
jlong dump_start() const { return _dump_start; }
void set_dump_start(jlong pos);
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();
// writes a HPROF_HEAP_DUMP or HPROF_HEAP_DUMP_SEGMENT record
void write_dump_header();
// fixes up the length of the current dump record
void write_current_dump_record_length();
// fixes up the current dump record )and writes HPROF_HEAP_DUMP_END
// record in the case of a segmented heap dump)
void end_of_dump();
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;
_is_segmented_dump = false;
_dump_start = (jlong)-1;
_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;
}
// sets the dump starting position
void VM_HeapDumper::set_dump_start(jlong pos) {
_dump_start = pos;
}
// writes a HPROF_HEAP_DUMP or HPROF_HEAP_DUMP_SEGMENT record
void VM_HeapDumper::write_dump_header() {
if (writer()->is_open()) {
if (is_segmented_dump()) {
writer()->write_u1(HPROF_HEAP_DUMP_SEGMENT);
} else {
writer()->write_u1(HPROF_HEAP_DUMP);
}
writer()->write_u4(0); // current ticks
// record the starting position for the dump (its length will be fixed up later)
set_dump_start(writer()->current_offset());
writer()->write_u4(0);
}
}
// fixes up the length of the current dump record
void VM_HeapDumper::write_current_dump_record_length() {
if (writer()->is_open()) {
assert(dump_start() >= 0, "no dump start recorded");
// calculate the size of the dump record
jlong dump_end = writer()->current_offset();
jlong dump_len = (dump_end - dump_start() - 4);
// record length must fit in a u4
if (dump_len > (jlong)(4L*(jlong)G)) {
warning("record is too large");
}
// seek to the dump start and fix-up the length
writer()->seek_to_offset(dump_start());
writer()->write_u4((u4)dump_len);
// adjust the total size written to keep the bytes written correct.
writer()->adjust_bytes_written(-((long) sizeof(u4)));
// seek to dump end so we can continue
writer()->seek_to_offset(dump_end);
// no current dump record
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()) {
if (is_segmented_dump()) {
// don't use current_offset that would be too expensive on a per record basis
jlong dump_end = writer()->bytes_written() + writer()->bytes_unwritten();
assert(dump_end == writer()->current_offset(), "checking");
jlong dump_len = (dump_end - dump_start() - 4);
assert(dump_len >= 0 && dump_len <= max_juint, "bad dump length");
if (dump_len > (jlong)HeapDumpSegmentSize) {
write_current_dump_record_length();
write_dump_header();
}
}
}
}
// fixes up the current dump record )and writes HPROF_HEAP_DUMP_END
// record in the case of a segmented heap dump)
void VM_HeapDumper::end_of_dump() {
if (writer()->is_open()) {
write_current_dump_record_length();
// for segmented dump we write the end record
if (is_segmented_dump()) {
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, ®_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
//
// 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.
//
// The HPROF_HEAP_DUMP record has a length following 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 - use 1.0.2 for large heaps, otherwise 1.0.1
size_t used = ch->used();
const char* header;
if (used > (size_t)SegmentedHeapDumpThreshold) {
set_segmented_dump();
header = "JAVA PROFILE 1.0.2";
} else {
header = "JAVA PROFILE 1.0.1";
}
// 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 or HPROF_HEAP_DUMP_SEGMENT
write_dump_header();
// 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. When
// generated a segmented heap dump this allows us to check if the current
// segment exceeds a threshold and if so, then 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);
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. In the case of a segmented
// heap then the HPROF_HEAP_DUMP_END record is also written.
end_of_dump();
// 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.
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) {
char msg[256];
sprintf(msg, "Heap dump file created [%s bytes in %3.3f secs]",
JLONG_FORMAT, timer()->seconds());
tty->print_cr(msg, writer.bytes_written());
} 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);
}
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