/*
* Copyright (c) 2016, 2019, 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 "jvm.h"
#include "classfile/classFileParser.hpp"
#include "classfile/classFileStream.hpp"
#include "classfile/javaClasses.inline.hpp"
#include "classfile/moduleEntry.hpp"
#include "classfile/modules.hpp"
#include "classfile/stackMapTable.hpp"
#include "classfile/symbolTable.hpp"
#include "classfile/verificationType.hpp"
#include "interpreter/bytecodes.hpp"
#include "jfr/instrumentation/jfrEventClassTransformer.hpp"
#include "jfr/jfr.hpp"
#include "jfr/jni/jfrJavaSupport.hpp"
#include "jfr/jni/jfrUpcalls.hpp"
#include "jfr/support/jfrEventClass.hpp"
#include "jfr/utilities/jfrBigEndian.hpp"
#include "jfr/writers/jfrBigEndianWriter.hpp"
#include "logging/log.hpp"
#include "memory/allocation.inline.hpp"
#include "memory/resourceArea.hpp"
#include "oops/array.hpp"
#include "oops/instanceKlass.hpp"
#include "oops/method.hpp"
#include "prims/jvmtiRedefineClasses.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/os.hpp"
#include "runtime/thread.inline.hpp"
#include "utilities/exceptions.hpp"
#include "utilities/globalDefinitions.hpp"
#include "utilities/macros.hpp"
static const u2 number_of_new_methods = 5;
static const u2 number_of_new_fields = 3;
static const int extra_stream_bytes = 0x280;
static const u2 invalid_cp_index = 0;
static const char* utf8_constants[] = {
"Code", // 0
"J", // 1
"commit", // 2
"eventHandler", // 3
"duration", // 4
"begin", // 5
"()V", // 6
"isEnabled", // 7
"()Z", // 8
"end", // 9
"shouldCommit", // 10
"startTime", // 11 // LAST_REQUIRED_UTF8
"Ljdk/jfr/internal/handlers/EventHandler;", // 12
"Ljava/lang/Object;", // 13
"<clinit>", // 14
"jdk/jfr/FlightRecorder", // 15
"register", // 16
"(Ljava/lang/Class;)V", // 17
"StackMapTable", // 18
"Exceptions", // 19
"LineNumberTable", // 20
"LocalVariableTable", // 21
"LocalVariableTypeTable", // 22
"RuntimeVisibleAnnotation", // 23
};
enum utf8_req_symbols {
UTF8_REQ_Code,
UTF8_REQ_J_FIELD_DESC,
UTF8_REQ_commit,
UTF8_REQ_eventHandler,
UTF8_REQ_duration,
UTF8_REQ_begin,
UTF8_REQ_EMPTY_VOID_METHOD_DESC,
UTF8_REQ_isEnabled,
UTF8_REQ_EMPTY_BOOLEAN_METHOD_DESC,
UTF8_REQ_end,
UTF8_REQ_shouldCommit,
UTF8_REQ_startTime,
NOF_UTF8_REQ_SYMBOLS
};
enum utf8_opt_symbols {
UTF8_OPT_eventHandler_FIELD_DESC = NOF_UTF8_REQ_SYMBOLS,
UTF8_OPT_LjavaLangObject,
UTF8_OPT_clinit,
UTF8_OPT_FlightRecorder,
UTF8_OPT_register,
UTF8_OPT_CLASS_VOID_METHOD_DESC,
UTF8_OPT_StackMapTable,
UTF8_OPT_Exceptions,
UTF8_OPT_LineNumberTable,
UTF8_OPT_LocalVariableTable,
UTF8_OPT_LocalVariableTypeTable,
UTF8_OPT_RuntimeVisibleAnnotation,
NOF_UTF8_SYMBOLS
};
static u1 empty_void_method_code_attribute[] = {
0x0,
0x0,
0x0,
0xd, // attribute len
0x0,
0x0, // max stack
0x0,
0x1, // max locals
0x0,
0x0,
0x0,
0x1, // code length
Bytecodes::_return,
0x0,
0x0, // ex table len
0x0,
0x0 // attributes_count
};
static u1 boolean_method_code_attribute[] = {
0x0,
0x0,
0x0,
0xe,
0x0,
0x1, // max stack
0x0,
0x1, // max locals
0x0,
0x0,
0x0,
0x2,
Bytecodes::_iconst_0,
Bytecodes::_ireturn,
0x0,
0x0, // ex table len
0x0,
0x0, // attributes_count
};
// annotation processing support
enum { // initial annotation layout
atype_off = 0, // utf8 such as 'Ljava/lang/annotation/Retention;'
count_off = 2, // u2 such as 1 (one value)
member_off = 4, // utf8 such as 'value'
tag_off = 6, // u1 such as 'c' (type) or 'e' (enum)
e_tag_val = 'e',
e_type_off = 7, // utf8 such as 'Ljava/lang/annotation/RetentionPolicy;'
e_con_off = 9, // utf8 payload, such as 'SOURCE', 'CLASS', 'RUNTIME'
e_size = 11, // end of 'e' annotation
c_tag_val = 'c', // payload is type
c_con_off = 7, // utf8 payload, such as 'I'
c_size = 9, // end of 'c' annotation
s_tag_val = 's', // payload is String
s_con_off = 7, // utf8 payload, such as 'Ljava/lang/String;'
s_size = 9,
min_size = 6 // smallest possible size (zero members)
};
static int skip_annotation_value(const address, int, int); // fwd decl
// Skip an annotation. Return >=limit if there is any problem.
static int next_annotation_index(const address buffer, int limit, int index) {
assert(buffer != NULL, "invariant");
index += 2; // skip atype
if ((index += 2) >= limit) {
return limit;
}
int nof_members = JfrBigEndian::read<u2>(buffer + index - 2);
while (--nof_members >= 0 && index < limit) {
index += 2; // skip member
index = skip_annotation_value(buffer, limit, index);
}
return index;
}
// Skip an annotation value. Return >=limit if there is any problem.
static int skip_annotation_value(const address buffer, int limit, int index) {
assert(buffer != NULL, "invariant");
// value := switch (tag:u1) {
// case B, C, I, S, Z, D, F, J, c: con:u2;
// case e: e_class:u2 e_name:u2;
// case s: s_con:u2;
// case [: do(nval:u2) {value};
// case @: annotation;
// case s: s_con:u2;
// }
if ((index += 1) >= limit) {
return limit;
}
const u1 tag = buffer[index - 1];
switch (tag) {
case 'B':
case 'C':
case 'I':
case 'S':
case 'Z':
case 'D':
case 'F':
case 'J':
case 'c':
case 's':
index += 2; // skip con or s_con
break;
case 'e':
index += 4; // skip e_class, e_name
break;
case '[':
{
if ((index += 2) >= limit) {
return limit;
}
int nof_values = JfrBigEndian::read<u2>(buffer + index - 2);
while (--nof_values >= 0 && index < limit) {
index = skip_annotation_value(buffer, limit, index);
}
}
break;
case '@':
index = next_annotation_index(buffer, limit, index);
break;
default:
return limit; // bad tag byte
}
return index;
}
static const u2 number_of_elements_offset = (u2)2;
static const u2 element_name_offset = (u2)(number_of_elements_offset + 2);
static const u2 element_name_size = (u2)2;
static const u2 value_type_relative_offset = (u2)2;
static const u2 value_relative_offset = (u2)(value_type_relative_offset + 1);
// see JVMS - 4.7.16. The RuntimeVisibleAnnotations Attribute
class AnnotationElementIterator : public StackObj {
private:
const InstanceKlass* _ik;
const address _buffer;
const u2 _limit; // length of annotation
mutable u2 _current; // element
mutable u2 _next; // element
u2 value_index() const {
return JfrBigEndian::read<u2>(_buffer + _current + value_relative_offset);
}
public:
AnnotationElementIterator(const InstanceKlass* ik, address buffer, u2 limit) : _ik(ik),
_buffer(buffer),
_limit(limit),
_current(element_name_offset),
_next(element_name_offset) {
assert(_buffer != NULL, "invariant");
assert(_next == element_name_offset, "invariant");
assert(_current == element_name_offset, "invariant");
}
bool has_next() const {
return _next < _limit;
}
void move_to_next() const {
assert(has_next(), "invariant");
_current = _next;
if (_next < _limit) {
_next = skip_annotation_value(_buffer, _limit, _next + element_name_size);
}
assert(_next <= _limit, "invariant");
assert(_current <= _limit, "invariant");
}
u2 number_of_elements() const {
return JfrBigEndian::read<u2>(_buffer + number_of_elements_offset);
}
const Symbol* name() const {
assert(_current < _next, "invariant");
return _ik->constants()->symbol_at(JfrBigEndian::read<u2>(_buffer + _current));
}
char value_type() const {
return JfrBigEndian::read<u1>(_buffer + _current + value_type_relative_offset);
}
jint read_int() const {
return _ik->constants()->int_at(value_index());
}
bool read_bool() const {
return read_int() != 0;
}
};
class AnnotationIterator : public StackObj {
private:
const InstanceKlass* _ik;
// ensure _limit field is declared before _buffer
u2 _limit; // length of annotations array
const address _buffer;
mutable u2 _current; // annotation
mutable u2 _next; // annotation
public:
AnnotationIterator(const InstanceKlass* ik, AnnotationArray* ar) : _ik(ik),
_limit(ar != NULL ? ar->length() : 0),
_buffer(_limit > 2 ? ar->adr_at(2) : NULL),
_current(0),
_next(0) {
if (_buffer != NULL) {
_limit -= 2; // subtract sizeof(u2) number of annotations field
}
}
bool has_next() const {
return _next < _limit;
}
void move_to_next() const {
assert(has_next(), "invariant");
_current = _next;
if (_next < _limit) {
_next = next_annotation_index(_buffer, _limit, _next);
}
assert(_next <= _limit, "invariant");
assert(_current <= _limit, "invariant");
}
const AnnotationElementIterator elements() const {
assert(_current < _next, "invariant");
return AnnotationElementIterator(_ik, _buffer + _current, _next - _current);
}
const Symbol* type() const {
assert(_buffer != NULL, "invariant");
assert(_current < _limit, "invariant");
return _ik->constants()->symbol_at(JfrBigEndian::read<u2>(_buffer + _current));
}
};
static const char value_name[] = "value";
static bool has_annotation(const InstanceKlass* ik, const Symbol* annotation_type, bool& value) {
assert(annotation_type != NULL, "invariant");
AnnotationArray* class_annotations = ik->class_annotations();
if (class_annotations == NULL) {
return false;
}
const AnnotationIterator annotation_iterator(ik, class_annotations);
while (annotation_iterator.has_next()) {
annotation_iterator.move_to_next();
if (annotation_iterator.type() == annotation_type) {
// target annotation found
static const Symbol* value_symbol =
SymbolTable::probe(value_name, sizeof value_name - 1);
assert(value_symbol != NULL, "invariant");
const AnnotationElementIterator element_iterator = annotation_iterator.elements();
while (element_iterator.has_next()) {
element_iterator.move_to_next();
if (value_symbol == element_iterator.name()) {
// "value" element
assert('Z' == element_iterator.value_type(), "invariant");
value = element_iterator.read_bool();
return true;
}
}
}
}
return false;
}
// Evaluate to the value of the first found Symbol* annotation type.
// Searching moves upwards in the klass hierarchy in order to support
// inherited annotations in addition to the ability to override.
static bool annotation_value(const InstanceKlass* ik, const Symbol* annotation_type, bool& value) {
assert(ik != NULL, "invariant");
assert(annotation_type != NULL, "invariant");
assert(JdkJfrEvent::is_a(ik), "invariant");
if (has_annotation(ik, annotation_type, value)) {
return true;
}
InstanceKlass* const super = InstanceKlass::cast(ik->super());
return super != NULL && JdkJfrEvent::is_a(super) ? annotation_value(super, annotation_type, value) : false;
}
static const char jdk_jfr_module_name[] = "jdk.jfr";
static bool java_base_can_read_jdk_jfr() {
static bool can_read = false;
if (can_read) {
return true;
}
static Symbol* jdk_jfr_module_symbol = NULL;
if (jdk_jfr_module_symbol == NULL) {
jdk_jfr_module_symbol = SymbolTable::probe(jdk_jfr_module_name, sizeof jdk_jfr_module_name - 1);
if (jdk_jfr_module_symbol == NULL) {
return false;
}
}
assert(jdk_jfr_module_symbol != NULL, "invariant");
ModuleEntryTable* const table = Modules::get_module_entry_table(Handle());
assert(table != NULL, "invariant");
const ModuleEntry* const java_base_module = table->javabase_moduleEntry();
if (java_base_module == NULL) {
return false;
}
assert(java_base_module != NULL, "invariant");
ModuleEntry* const jdk_jfr_module = table->lookup_only(jdk_jfr_module_symbol);
if (jdk_jfr_module == NULL) {
return false;
}
assert(jdk_jfr_module != NULL, "invariant");
if (java_base_module->can_read(jdk_jfr_module)) {
can_read = true;
}
return can_read;
}
static const char registered_constant[] = "Ljdk/jfr/Registered;";
// Evaluate to the value of the first found "Ljdk/jfr/Registered;" annotation.
// Searching moves upwards in the klass hierarchy in order to support
// inherited annotations in addition to the ability to override.
static bool should_register_klass(const InstanceKlass* ik, bool& untypedEventHandler) {
assert(ik != NULL, "invariant");
assert(JdkJfrEvent::is_a(ik), "invariant");
assert(!untypedEventHandler, "invariant");
static const Symbol* registered_symbol = NULL;
if (registered_symbol == NULL) {
registered_symbol = SymbolTable::probe(registered_constant, sizeof registered_constant - 1);
if (registered_symbol == NULL) {
untypedEventHandler = true;
return false;
}
}
assert(registered_symbol != NULL, "invariant");
bool value = false; // to be set by annotation_value
untypedEventHandler = !(annotation_value(ik, registered_symbol, value) || java_base_can_read_jdk_jfr());
return value;
}
/*
* Map an utf8 constant back to its CONSTANT_UTF8_INFO
*/
static u2 utf8_info_index(const InstanceKlass* ik, const Symbol* const target, TRAPS) {
assert(target != NULL, "invariant");
const ConstantPool* cp = ik->constants();
const int cp_len = cp->length();
for (u2 index = 1; index < cp_len; ++index) {
const constantTag tag = cp->tag_at(index);
if (tag.is_utf8()) {
const Symbol* const utf8_sym = cp->symbol_at(index);
assert(utf8_sym != NULL, "invariant");
if (utf8_sym == target) {
return index;
}
}
}
// not in constant pool
return invalid_cp_index;
}
#ifdef ASSERT
static bool is_index_within_range(u2 index, u2 orig_cp_len, u2 new_cp_entries_len) {
return index > 0 && index < orig_cp_len + new_cp_entries_len;
}
#endif
static u2 add_utf8_info(JfrBigEndianWriter& writer, const char* utf8_constant, u2 orig_cp_len, u2& new_cp_entries_len) {
assert(utf8_constant != NULL, "invariant");
writer.write<u1>(JVM_CONSTANT_Utf8);
writer.write_utf8_u2_len(utf8_constant);
assert(writer.is_valid(), "invariant");
// return index for the added utf8 info
return orig_cp_len + new_cp_entries_len++;
}
static u2 add_method_ref_info(JfrBigEndianWriter& writer,
u2 cls_name_index,
u2 method_index,
u2 desc_index,
u2 orig_cp_len,
u2& number_of_new_constants,
TRAPS) {
assert(cls_name_index != invalid_cp_index, "invariant");
assert(method_index != invalid_cp_index, "invariant");
assert(desc_index != invalid_cp_index, "invariant");
assert(is_index_within_range(cls_name_index, orig_cp_len, number_of_new_constants), "invariant");
assert(is_index_within_range(method_index, orig_cp_len, number_of_new_constants), "invariant");
assert(is_index_within_range(desc_index, orig_cp_len, number_of_new_constants), "invariant");
writer.write<u1>(JVM_CONSTANT_Class);
writer.write<u2>(cls_name_index);
const u2 cls_entry_index = orig_cp_len + number_of_new_constants;
++number_of_new_constants;
writer.write<u1>(JVM_CONSTANT_NameAndType);
writer.write<u2>(method_index);
writer.write<u2>(desc_index);
const u2 nat_entry_index = orig_cp_len + number_of_new_constants;
++number_of_new_constants;
writer.write<u1>(JVM_CONSTANT_Methodref);
writer.write<u2>(cls_entry_index);
writer.write<u2>(nat_entry_index);
// post-increment number_of_new_constants
// value returned is the index to the added method_ref
return orig_cp_len + number_of_new_constants++;
}
static u2 add_flr_register_method_constants(JfrBigEndianWriter& writer,
const u2* utf8_indexes,
u2 orig_cp_len,
u2& number_of_new_constants,
TRAPS) {
assert(utf8_indexes != NULL, "invariant");
return add_method_ref_info(writer,
utf8_indexes[UTF8_OPT_FlightRecorder],
utf8_indexes[UTF8_OPT_register],
utf8_indexes[UTF8_OPT_CLASS_VOID_METHOD_DESC],
orig_cp_len,
number_of_new_constants,
THREAD);
}
/*
* field_info {
* u2 access_flags;
* u2 name_index;
* u2 descriptor_index;
* u2 attributes_count;
* attribute_info attributes[attributes_count];
* }
*/
static jlong add_field_info(JfrBigEndianWriter& writer, u2 name_index, u2 desc_index, bool is_static = false) {
assert(name_index != invalid_cp_index, "invariant");
assert(desc_index != invalid_cp_index, "invariant");
DEBUG_ONLY(const jlong start_offset = writer.current_offset();)
writer.write<u2>(JVM_ACC_SYNTHETIC | JVM_ACC_PRIVATE | (is_static ? JVM_ACC_STATIC : JVM_ACC_TRANSIENT)); // flags
writer.write(name_index);
writer.write(desc_index);
writer.write((u2)0x0); // attributes_count
assert(writer.is_valid(), "invariant");
DEBUG_ONLY(assert(start_offset + 8 == writer.current_offset(), "invariant");)
return writer.current_offset();
}
static u2 add_field_infos(JfrBigEndianWriter& writer, const u2* utf8_indexes, bool untypedEventHandler) {
assert(utf8_indexes != NULL, "invariant");
add_field_info(writer,
utf8_indexes[UTF8_REQ_eventHandler],
untypedEventHandler ? utf8_indexes[UTF8_OPT_LjavaLangObject] : utf8_indexes[UTF8_OPT_eventHandler_FIELD_DESC],
true); // static
add_field_info(writer,
utf8_indexes[UTF8_REQ_startTime],
utf8_indexes[UTF8_REQ_J_FIELD_DESC]);
add_field_info(writer,
utf8_indexes[UTF8_REQ_duration],
utf8_indexes[UTF8_REQ_J_FIELD_DESC]);
return number_of_new_fields;
}
/*
* method_info {
* u2 access_flags;
* u2 name_index;
* u2 descriptor_index;
* u2 attributes_count;
* attribute_info attributes[attributes_count];
* }
*
* Code_attribute {
* u2 attribute_name_index;
* u4 attribute_length;
* u2 max_stack;
* u2 max_locals;
* u4 code_length;
* u1 code[code_length];
* u2 exception_table_length;
* { u2 start_pc;
* u2 end_pc;
* u2 handler_pc;
* u2 catch_type;
* } exception_table[exception_table_length];
* u2 attributes_count;
* attribute_info attributes[attributes_count];
* }
*/
static jlong add_method_info(JfrBigEndianWriter& writer,
u2 name_index,
u2 desc_index,
u2 code_index,
const u1* const code,
const size_t code_len) {
assert(name_index > 0, "invariant");
assert(desc_index > 0, "invariant");
assert(code_index > 0, "invariant");
DEBUG_ONLY(const jlong start_offset = writer.current_offset();)
writer.write<u2>(JVM_ACC_SYNTHETIC | JVM_ACC_PUBLIC); // flags
writer.write(name_index);
writer.write(desc_index);
writer.write<u2>(0x1); // attributes_count ; 1 for "Code" attribute
assert(writer.is_valid(), "invariant");
DEBUG_ONLY(assert(start_offset + 8 == writer.current_offset(), "invariant");)
// Code attribute
writer.write(code_index); // "Code"
writer.bytes(code, code_len);
DEBUG_ONLY(assert((start_offset + 8 + 2 + (jlong)code_len) == writer.current_offset(), "invariant");)
return writer.current_offset();
}
/*
* On return, the passed stream will be positioned
* just after the constant pool section in the classfile
* and the cp length is returned.
*
* Stream should come in at the start position.
*/
static u2 position_stream_after_cp(const ClassFileStream* stream) {
assert(stream != NULL, "invariant");
assert(stream->current_offset() == 0, "invariant");
stream->skip_u4_fast(2); // 8 bytes skipped
const u2 cp_len = stream->get_u2_fast();
assert(cp_len > 0, "invariant");
// now spin the stream position to just after the constant pool
for (u2 index = 1; index < cp_len; ++index) {
const u1 tag = stream->get_u1_fast(); // cp tag
switch (tag) {
case JVM_CONSTANT_Class:
case JVM_CONSTANT_String: {
stream->skip_u2_fast(1); // skip 2 bytes
continue;
}
case JVM_CONSTANT_Fieldref:
case JVM_CONSTANT_Methodref:
case JVM_CONSTANT_InterfaceMethodref:
case JVM_CONSTANT_Integer:
case JVM_CONSTANT_Float:
case JVM_CONSTANT_NameAndType:
case JVM_CONSTANT_InvokeDynamic: {
stream->skip_u4_fast(1); // skip 4 bytes
continue;
}
case JVM_CONSTANT_Long:
case JVM_CONSTANT_Double: {
stream->skip_u4_fast(2); // skip 8 bytes
// Skip entry following eigth-byte constant, see JVM book p. 98
++index;
continue;
}
case JVM_CONSTANT_Utf8: {
u2 utf8_length = stream->get_u2_fast();
stream->skip_u1_fast(utf8_length); // skip 2 + len bytes
continue;
}
case JVM_CONSTANT_MethodHandle:
case JVM_CONSTANT_MethodType: {
if (tag == JVM_CONSTANT_MethodHandle) {
stream->skip_u1_fast(1);
stream->skip_u2_fast(1); // skip 3 bytes
}
else if (tag == JVM_CONSTANT_MethodType) {
stream->skip_u2_fast(1); // skip 3 bytes
}
}
continue;
default:
assert(false, "error in skip logic!");
break;
} // end switch(tag)
}
return cp_len;
}
/*
* On return, the passed stream will be positioned
* just after the fields section in the classfile
* and the number of fields will be returned.
*
* Stream should come in positioned just before fields_count
*/
static u2 position_stream_after_fields(const ClassFileStream* stream) {
assert(stream != NULL, "invariant");
assert(stream->current_offset() > 0, "invariant");
// fields len
const u2 orig_fields_len = stream->get_u2_fast();
// fields
for (u2 i = 0; i < orig_fields_len; ++i) {
stream->skip_u2_fast(3);
const u2 attrib_info_len = stream->get_u2_fast();
for (u2 j = 0; j < attrib_info_len; ++j) {
stream->skip_u2_fast(1);
const u4 attrib_len = stream->get_u4_fast();
stream->skip_u1_fast(attrib_len);
}
}
return orig_fields_len;
}
/*
* On return, the passed stream will be positioned
* just after the methods section in the classfile
* and the number of methods will be returned.
*
* Stream should come in positioned just before methods_count
*/
static u2 position_stream_after_methods(JfrBigEndianWriter& writer,
const ClassFileStream* stream,
const u2* utf8_indexes,
bool register_klass,
const Method* clinit_method,
u4& orig_method_len_offset) {
assert(stream != NULL, "invariant");
assert(stream->current_offset() > 0, "invariant");
assert(utf8_indexes != NULL, "invariant");
// We will come back to this location when we
// know how many methods there will be.
writer.reserve(sizeof(u2));
const u2 orig_methods_len = stream->get_u2_fast();
// Move copy position past original method_count
// in order to not copy the original count
orig_method_len_offset += sizeof(u2);
for (u2 i = 0; i < orig_methods_len; ++i) {
const u4 method_offset = stream->current_offset();
stream->skip_u2_fast(1); // Access Flags
const u2 name_index = stream->get_u2_fast(); // Name index
stream->skip_u2_fast(1); // Descriptor index
const u2 attributes_count = stream->get_u2_fast();
for (u2 j = 0; j < attributes_count; ++j) {
stream->skip_u2_fast(1);
const u4 attrib_len = stream->get_u4_fast();
stream->skip_u1_fast(attrib_len);
}
if (clinit_method != NULL && name_index == clinit_method->name_index()) {
// The method just parsed is an existing <clinit> method.
// If the class has the @Registered(false) annotation, i.e. marking a class
// for opting out from automatic registration, then we do not need to do anything.
if (!register_klass) {
continue;
}
// Automatic registration with the jfr system is acccomplished
// by pre-pending code to the <clinit> method of the class.
// We will need to re-create a new <clinit> in a later step.
// For now, ensure that this method is excluded from the methods
// being copied.
writer.bytes(stream->buffer() + orig_method_len_offset,
method_offset - orig_method_len_offset);
assert(writer.is_valid(), "invariant");
// Update copy position to skip copy of <clinit> method
orig_method_len_offset = stream->current_offset();
}
}
return orig_methods_len;
}
static u2 add_method_infos(JfrBigEndianWriter& writer, const u2* utf8_indexes) {
assert(utf8_indexes != NULL, "invariant");
add_method_info(writer,
utf8_indexes[UTF8_REQ_begin],
utf8_indexes[UTF8_REQ_EMPTY_VOID_METHOD_DESC],
utf8_indexes[UTF8_REQ_Code],
empty_void_method_code_attribute,
sizeof(empty_void_method_code_attribute));
assert(writer.is_valid(), "invariant");
add_method_info(writer,
utf8_indexes[UTF8_REQ_end],
utf8_indexes[UTF8_REQ_EMPTY_VOID_METHOD_DESC],
utf8_indexes[UTF8_REQ_Code],
empty_void_method_code_attribute,
sizeof(empty_void_method_code_attribute));
assert(writer.is_valid(), "invariant");
add_method_info(writer,
utf8_indexes[UTF8_REQ_commit],
utf8_indexes[UTF8_REQ_EMPTY_VOID_METHOD_DESC],
utf8_indexes[UTF8_REQ_Code],
empty_void_method_code_attribute,
sizeof(empty_void_method_code_attribute));
assert(writer.is_valid(), "invariant");
add_method_info(writer,
utf8_indexes[UTF8_REQ_isEnabled],
utf8_indexes[UTF8_REQ_EMPTY_BOOLEAN_METHOD_DESC],
utf8_indexes[UTF8_REQ_Code],
boolean_method_code_attribute,
sizeof(boolean_method_code_attribute));
assert(writer.is_valid(), "invariant");
add_method_info(writer,
utf8_indexes[UTF8_REQ_shouldCommit],
utf8_indexes[UTF8_REQ_EMPTY_BOOLEAN_METHOD_DESC],
utf8_indexes[UTF8_REQ_Code],
boolean_method_code_attribute,
sizeof(boolean_method_code_attribute));
assert(writer.is_valid(), "invariant");
return number_of_new_methods;
}
static void adjust_exception_table(JfrBigEndianWriter& writer, u2 bci_adjustment_offset, const Method* method, TRAPS) {
const u2 ex_table_length = method != NULL ? (u2)method->exception_table_length() : 0;
writer.write<u2>(ex_table_length); // Exception table length
if (ex_table_length > 0) {
assert(method != NULL, "invariant");
const ExceptionTableElement* const ex_elements = method->exception_table_start();
for (int i = 0; i < ex_table_length; ++i) {
assert(ex_elements != NULL, "invariant");
writer.write<u2>(ex_elements[i].start_pc + bci_adjustment_offset);
writer.write<u2>(ex_elements[i].end_pc + bci_adjustment_offset);
writer.write<u2>(ex_elements[i].handler_pc + bci_adjustment_offset);
writer.write<u2>(ex_elements[i].catch_type_index); // no adjustment
}
}
}
enum StackMapFrameTypes {
SAME_FRAME_BEGIN = 0,
SAME_FRAME_END = 63,
SAME_LOCALS_1_STACK_ITEM_FRAME_BEGIN = 64,
SAME_LOCALS_1_STACK_ITEM_FRAME_END = 127,
SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED = 247,
CHOP_FRAME_BEGIN = 248,
CHOP_FRAME_END = 250,
SAME_FRAME_EXTENDED = 251,
APPEND_FRAME_BEGIN = 252,
APPEND_FRAME_END = 254,
FULL_FRAME = 255
};
static void adjust_stack_map(JfrBigEndianWriter& writer,
Array<u1>* stack_map,
const u2* utf8_indexes,
u2 bci_adjustment_offset,
TRAPS) {
assert(stack_map != NULL, "invariant");
assert(utf8_indexes != NULL, "invariant");
writer.write<u2>(utf8_indexes[UTF8_OPT_StackMapTable]);
const jlong stack_map_attrib_len_offset = writer.current_offset();
writer.reserve(sizeof(u4));
StackMapStream stream(stack_map);
const u2 stack_map_entries = stream.get_u2(THREAD);
// number of entries
writer.write<u2>(stack_map_entries); // new stack map entry added
const u1 frame_type = stream.get_u1(THREAD);
// SAME_FRAME and SAME_LOCALS_1_STACK_ITEM_FRAME encode
// their offset_delta into the actual frame type itself.
// If such a frame type is the first frame, then we transform
// it to a SAME_FRAME_EXTENDED or a SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED frame.
// This is done in order to not overflow frame types accidentally
// when adjusting the offset_delta. In changing the frame types,
// we can work with an explicit u2 offset_delta field (like the other frame types)
if (frame_type <= SAME_FRAME_END) {
writer.write<u1>(SAME_FRAME_EXTENDED);
writer.write<u2>(frame_type + bci_adjustment_offset);
} else if (frame_type >= SAME_LOCALS_1_STACK_ITEM_FRAME_BEGIN &&
frame_type <= SAME_LOCALS_1_STACK_ITEM_FRAME_END) {
writer.write<u1>(SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED);
writer.write<u2>((frame_type - SAME_LOCALS_1_STACK_ITEM_FRAME_BEGIN) + bci_adjustment_offset);
} else if (frame_type >= SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED) {
// SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED to FULL_FRAME
// has a u2 offset_delta field
writer.write<u1>(frame_type);
writer.write<u2>(stream.get_u2(THREAD) + bci_adjustment_offset);
} else {
assert(false, "stackMapFrame type is invalid");
}
while (!stream.at_end()) {
writer.write<u1>(stream.get_u1(THREAD));
}
u4 stack_map_attrib_len = writer.current_offset() - stack_map_attrib_len_offset;
// the stack_map_table_attributes_length value is exclusive
stack_map_attrib_len -= sizeof(u4);
writer.write_at_offset(stack_map_attrib_len, stack_map_attrib_len_offset);
}
static void adjust_line_number_table(JfrBigEndianWriter& writer,
const u2* utf8_indexes,
u4 bci_adjustement_offset,
const Method* method,
TRAPS) {
assert(utf8_indexes != NULL, "invariant");
assert(method != NULL, "invariant");
assert(method->has_linenumber_table(), "invariant");
writer.write(utf8_indexes[UTF8_OPT_LineNumberTable]);
const jlong lnt_attributes_length_offset = writer.current_offset();
writer.reserve(sizeof(u4));
const jlong lnt_attributes_entries_offset = writer.current_offset();
writer.reserve(sizeof(u2));
u1* lnt = method->compressed_linenumber_table();
CompressedLineNumberReadStream lnt_stream(lnt);
u2 line_number_table_entries = 0;
while (lnt_stream.read_pair()) {
++line_number_table_entries;
const u2 bci = (u2)lnt_stream.bci();
writer.write<u2>(bci + (u2)bci_adjustement_offset);
writer.write<u2>((u2)lnt_stream.line());
}
writer.write_at_offset(line_number_table_entries, lnt_attributes_entries_offset);
u4 lnt_table_attributes_len = writer.current_offset() - lnt_attributes_length_offset;
// the line_number_table_attributes_length value is exclusive
lnt_table_attributes_len -= sizeof(u4);
writer.write_at_offset(lnt_table_attributes_len, lnt_attributes_length_offset);
}
// returns the number of lvtt entries
static u2 adjust_local_variable_table(JfrBigEndianWriter& writer,
const u2* utf8_indexes,
u2 bci_adjustment_offset,
const Method* method,
TRAPS) {
assert(utf8_indexes != NULL, "invariant");
assert(method != NULL, "invariant");
assert(method->has_localvariable_table(), "invariant");
writer.write<u2>(utf8_indexes[UTF8_OPT_LocalVariableTable]);
const jlong lvt_attributes_length_offset = writer.current_offset();
writer.reserve(sizeof(u4));
const int lvt_len = method->localvariable_table_length();
writer.write<u2>((u2)lvt_len);
const LocalVariableTableElement* table = method->localvariable_table_start();
assert(table != NULL, "invariant");
u2 num_lvtt_entries = 0;
for (int i = 0; i < lvt_len; ++i) {
writer.write<u2>(table[i].start_bci + bci_adjustment_offset);
writer.write<u2>(table[i].length);
writer.write<u2>(table[i].name_cp_index);
writer.write<u2>(table[i].descriptor_cp_index);
writer.write<u2>(table[i].slot);
if (table[i].signature_cp_index > 0) {
++num_lvtt_entries;
}
}
u4 lvt_table_attributes_len = writer.current_offset() - lvt_attributes_length_offset;
// the lvt_table_attributes_length value is exclusive
lvt_table_attributes_len -= sizeof(u4);
writer.write_at_offset(lvt_table_attributes_len, lvt_attributes_length_offset);
return num_lvtt_entries;
}
static void adjust_local_variable_type_table(JfrBigEndianWriter& writer,
const u2* utf8_indexes,
u2 bci_adjustment_offset,
u2 num_lvtt_entries,
const Method* method,
TRAPS) {
assert(num_lvtt_entries > 0, "invariant");
writer.write<u2>(utf8_indexes[UTF8_OPT_LocalVariableTypeTable]);
const jlong lvtt_attributes_length_offset = writer.current_offset();
writer.reserve(sizeof(u4));
writer.write<u2>(num_lvtt_entries);
const LocalVariableTableElement* table = method->localvariable_table_start();
assert(table != NULL, "invariant");
const int lvt_len = method->localvariable_table_length();
for (int i = 0; i < lvt_len; ++i) {
if (table[i].signature_cp_index > 0) {
writer.write<u2>(table[i].start_bci + bci_adjustment_offset);
writer.write<u2>(table[i].length);
writer.write<u2>(table[i].name_cp_index);
writer.write<u2>(table[i].signature_cp_index);
writer.write<u2>(table[i].slot);
}
}
u4 lvtt_table_attributes_len = writer.current_offset() - lvtt_attributes_length_offset;
// the lvtt_table_attributes_length value is exclusive
lvtt_table_attributes_len -= sizeof(u4);
writer.write_at_offset(lvtt_table_attributes_len, lvtt_attributes_length_offset);
}
static void adjust_code_attributes(JfrBigEndianWriter& writer,
const u2* utf8_indexes,
u2 bci_adjustment_offset,
const Method* clinit_method,
TRAPS) {
// "Code" attributes
assert(utf8_indexes != NULL, "invariant");
const jlong code_attributes_offset = writer.current_offset();
writer.reserve(sizeof(u2));
u2 number_of_code_attributes = 0;
if (clinit_method != NULL) {
Array<u1>* stack_map = clinit_method->stackmap_data();
if (stack_map != NULL) {
++number_of_code_attributes;
adjust_stack_map(writer, stack_map, utf8_indexes, bci_adjustment_offset, THREAD);
assert(writer.is_valid(), "invariant");
}
if (clinit_method != NULL && clinit_method->has_linenumber_table()) {
++number_of_code_attributes;
adjust_line_number_table(writer, utf8_indexes, bci_adjustment_offset, clinit_method, THREAD);
assert(writer.is_valid(), "invariant");
}
if (clinit_method != NULL && clinit_method->has_localvariable_table()) {
++number_of_code_attributes;
const u2 num_of_lvtt_entries = adjust_local_variable_table(writer, utf8_indexes, bci_adjustment_offset, clinit_method, THREAD);
assert(writer.is_valid(), "invariant");
if (num_of_lvtt_entries > 0) {
++number_of_code_attributes;
adjust_local_variable_type_table(writer, utf8_indexes, bci_adjustment_offset, num_of_lvtt_entries, clinit_method, THREAD);
assert(writer.is_valid(), "invariant");
}
}
}
// Store the number of code_attributes
writer.write_at_offset(number_of_code_attributes, code_attributes_offset);
}
static jlong insert_clinit_method(const InstanceKlass* ik,
const ClassFileParser& parser,
JfrBigEndianWriter& writer,
u2 orig_constant_pool_len,
const u2* utf8_indexes,
const u2 register_method_ref_index,
const Method* clinit_method,
TRAPS) {
assert(utf8_indexes != NULL, "invariant");
// The injected code length is always this value.
// This is to ensure that padding can be done
// where needed and to simplify size calculations.
static const u2 injected_code_length = 8;
const u2 name_index = utf8_indexes[UTF8_OPT_clinit];
assert(name_index != invalid_cp_index, "invariant");
const u2 desc_index = utf8_indexes[UTF8_REQ_EMPTY_VOID_METHOD_DESC];
const u2 max_stack = MAX2(clinit_method != NULL ? clinit_method->verifier_max_stack() : 1, 1);
const u2 max_locals = MAX2(clinit_method != NULL ? clinit_method->max_locals() : 0, 0);
const u2 orig_bytecodes_length = clinit_method != NULL ? (u2)clinit_method->code_size() : 0;
const address orig_bytecodes = clinit_method != NULL ? clinit_method->code_base() : NULL;
const u2 new_code_length = injected_code_length + orig_bytecodes_length;
DEBUG_ONLY(const jlong start_offset = writer.current_offset();)
writer.write<u2>(JVM_ACC_STATIC); // flags
writer.write<u2>(name_index);
writer.write<u2>(desc_index);
writer.write<u2>((u2)0x1); // attributes_count // "Code"
assert(writer.is_valid(), "invariant");
DEBUG_ONLY(assert(start_offset + 8 == writer.current_offset(), "invariant");)
// "Code" attribute
writer.write<u2>(utf8_indexes[UTF8_REQ_Code]); // "Code"
const jlong code_attribute_length_offset = writer.current_offset();
writer.reserve(sizeof(u4));
writer.write<u2>(max_stack); // max stack
writer.write<u2>(max_locals); // max locals
writer.write<u4>((u4)new_code_length); // code length
/* BEGIN CLINIT CODE */
// Note the use of ldc_w here instead of ldc.
// This is to handle all values of "this_class_index"
writer.write<u1>((u1)Bytecodes::_ldc_w);
writer.write<u2>((u2)parser.this_class_index()); // load constant "this class"
writer.write<u1>((u1)Bytecodes::_invokestatic);
// invoke "FlightRecorder.register(Ljava/lang/Class;")
writer.write<u2>(register_method_ref_index);
if (clinit_method == NULL) {
writer.write<u1>((u1)Bytecodes::_nop);
writer.write<u1>((u1)Bytecodes::_return);
} else {
// If we are pre-pending to original code,
// do padding to minimize disruption to the original.
// It might have dependencies on 4-byte boundaries
// i.e. lookupswitch and tableswitch instructions
writer.write<u1>((u1)Bytecodes::_nop);
writer.write<u1>((u1)Bytecodes::_nop);
// insert original clinit code
writer.bytes(orig_bytecodes, orig_bytecodes_length);
}
/* END CLINIT CODE */
assert(writer.is_valid(), "invariant");
adjust_exception_table(writer, injected_code_length, clinit_method, THREAD);
assert(writer.is_valid(), "invariant");
adjust_code_attributes(writer, utf8_indexes, injected_code_length, clinit_method, THREAD);
assert(writer.is_valid(), "invariant");
u4 code_attribute_len = writer.current_offset() - code_attribute_length_offset;
// the code_attribute_length value is exclusive
code_attribute_len -= sizeof(u4);
writer.write_at_offset(code_attribute_len, code_attribute_length_offset);
return writer.current_offset();
}
// Caller needs ResourceMark
static ClassFileStream* create_new_bytes_for_event_klass(const InstanceKlass* ik, const ClassFileParser& parser, TRAPS) {
DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(THREAD));
static const u2 public_final_flag_mask = JVM_ACC_PUBLIC | JVM_ACC_FINAL;
const ClassFileStream* const orig_stream = parser.clone_stream();
const int orig_stream_length = orig_stream->length();
// allocate an identically sized buffer
u1* const new_buffer = NEW_RESOURCE_ARRAY_IN_THREAD_RETURN_NULL(THREAD, u1, orig_stream_length);
if (new_buffer == NULL) {
return NULL;
}
assert(new_buffer != NULL, "invariant");
// memcpy the entire [B
memcpy(new_buffer, orig_stream->buffer(), orig_stream_length);
const u2 orig_cp_len = position_stream_after_cp(orig_stream);
assert(orig_cp_len > 0, "invariant");
assert(orig_stream->current_offset() > 0, "invariant");
orig_stream->skip_u2_fast(3); // access_flags, this_class_index, super_class_index
const u2 iface_len = orig_stream->get_u2_fast();
orig_stream->skip_u2_fast(iface_len);
// fields len
const u2 orig_fields_len = orig_stream->get_u2_fast();
// fields
for (u2 i = 0; i < orig_fields_len; ++i) {
orig_stream->skip_u2_fast(3);
const u2 attrib_info_len = orig_stream->get_u2_fast();
for (u2 j = 0; j < attrib_info_len; ++j) {
orig_stream->skip_u2_fast(1);
const u4 attrib_len = orig_stream->get_u4_fast();
orig_stream->skip_u1_fast(attrib_len);
}
}
// methods
const u2 orig_methods_len = orig_stream->get_u2_fast();
for (u2 i = 0; i < orig_methods_len; ++i) {
const u4 access_flag_offset = orig_stream->current_offset();
const u2 flags = orig_stream->get_u2_fast();
// Rewrite JVM_ACC_FINAL -> JVM_ACC_PUBLIC
if (public_final_flag_mask == flags) {
JfrBigEndianWriter accessflagsrewriter(new_buffer + access_flag_offset, sizeof(u2));
accessflagsrewriter.write<u2>(JVM_ACC_PUBLIC);
assert(accessflagsrewriter.is_valid(), "invariant");
}
orig_stream->skip_u2_fast(2);
const u2 attributes_count = orig_stream->get_u2_fast();
for (u2 j = 0; j < attributes_count; ++j) {
orig_stream->skip_u2_fast(1);
const u4 attrib_len = orig_stream->get_u4_fast();
orig_stream->skip_u1_fast(attrib_len);
}
}
return new ClassFileStream(new_buffer, orig_stream_length, NULL, ClassFileStream::verify);
}
// Attempt to locate an existing UTF8_INFO mapping the utf8_constant.
// If no UTF8_INFO exists, add (append) a new one to the constant pool.
static u2 find_or_add_utf8_info(JfrBigEndianWriter& writer,
const InstanceKlass* ik,
const char* const utf8_constant,
u2 orig_cp_len,
u2& added_cp_entries,
TRAPS) {
assert(utf8_constant != NULL, "invariant");
TempNewSymbol utf8_sym = SymbolTable::new_symbol(utf8_constant);
// lookup existing
const int utf8_orig_idx = utf8_info_index(ik, utf8_sym, THREAD);
if (utf8_orig_idx != invalid_cp_index) {
// existing constant pool entry found
return utf8_orig_idx;
}
// no existing match, need to add a new utf8 cp entry
assert(invalid_cp_index == utf8_orig_idx, "invariant");
// add / append new
return add_utf8_info(writer, utf8_constant, orig_cp_len, added_cp_entries);
}
/*
* This routine will resolve the required utf8_constants array
* to their constant pool indexes (mapping to their UTF8_INFO's)
* Only if a constant is actually needed and does not already exist
* will it be added.
*
* The passed in indexes array will be populated with the resolved indexes.
* The number of newly added constant pool entries is returned.
*/
static u2 resolve_utf8_indexes(JfrBigEndianWriter& writer,
const InstanceKlass* ik,
u2* const utf8_indexes,
u2 orig_cp_len,
const Method* clinit_method,
bool register_klass,
bool untypedEventHandler,
TRAPS) {
assert(utf8_indexes != NULL, "invariant");
u2 added_cp_entries = 0;
// resolve all required symbols
for (u2 index = 0; index < NOF_UTF8_REQ_SYMBOLS; ++index) {
utf8_indexes[index] = find_or_add_utf8_info(writer, ik, utf8_constants[index], orig_cp_len, added_cp_entries, THREAD);
}
// resolve optional constants
utf8_indexes[UTF8_OPT_eventHandler_FIELD_DESC] = untypedEventHandler ? invalid_cp_index :
find_or_add_utf8_info(writer, ik, utf8_constants[UTF8_OPT_eventHandler_FIELD_DESC], orig_cp_len, added_cp_entries, THREAD);
utf8_indexes[UTF8_OPT_LjavaLangObject] = untypedEventHandler ?
find_or_add_utf8_info(writer, ik, utf8_constants[UTF8_OPT_LjavaLangObject], orig_cp_len, added_cp_entries, THREAD) : invalid_cp_index;
if (register_klass) {
utf8_indexes[UTF8_OPT_clinit] =
find_or_add_utf8_info(writer, ik, utf8_constants[UTF8_OPT_clinit], orig_cp_len, added_cp_entries, THREAD);
utf8_indexes[UTF8_OPT_FlightRecorder] =
find_or_add_utf8_info(writer, ik, utf8_constants[UTF8_OPT_FlightRecorder], orig_cp_len, added_cp_entries, THREAD);
utf8_indexes[UTF8_OPT_register] =
find_or_add_utf8_info(writer, ik, utf8_constants[UTF8_OPT_register], orig_cp_len, added_cp_entries, THREAD);
utf8_indexes[UTF8_OPT_CLASS_VOID_METHOD_DESC] =
find_or_add_utf8_info(writer, ik, utf8_constants[UTF8_OPT_CLASS_VOID_METHOD_DESC], orig_cp_len, added_cp_entries, THREAD);
} else {
utf8_indexes[UTF8_OPT_clinit] = invalid_cp_index;
utf8_indexes[UTF8_OPT_FlightRecorder] = invalid_cp_index;
utf8_indexes[UTF8_OPT_register] = invalid_cp_index;
utf8_indexes[UTF8_OPT_CLASS_VOID_METHOD_DESC] = invalid_cp_index;
}
if (clinit_method != NULL && clinit_method->has_stackmap_table()) {
utf8_indexes[UTF8_OPT_StackMapTable] =
find_or_add_utf8_info(writer, ik, utf8_constants[UTF8_OPT_StackMapTable], orig_cp_len, added_cp_entries, THREAD);
} else {
utf8_indexes[UTF8_OPT_StackMapTable] = invalid_cp_index;
}
if (clinit_method != NULL && clinit_method->has_linenumber_table()) {
utf8_indexes[UTF8_OPT_LineNumberTable] =
find_or_add_utf8_info(writer, ik, utf8_constants[UTF8_OPT_LineNumberTable], orig_cp_len, added_cp_entries, THREAD);
} else {
utf8_indexes[UTF8_OPT_LineNumberTable] = invalid_cp_index;
}
if (clinit_method != NULL && clinit_method->has_localvariable_table()) {
utf8_indexes[UTF8_OPT_LocalVariableTable] =
find_or_add_utf8_info(writer, ik, utf8_constants[UTF8_OPT_LocalVariableTable], orig_cp_len, added_cp_entries, THREAD);
utf8_indexes[UTF8_OPT_LocalVariableTypeTable] =
find_or_add_utf8_info(writer, ik, utf8_constants[UTF8_OPT_LocalVariableTypeTable], orig_cp_len, added_cp_entries, THREAD);
} else {
utf8_indexes[UTF8_OPT_LocalVariableTable] = invalid_cp_index;
utf8_indexes[UTF8_OPT_LocalVariableTypeTable] = invalid_cp_index;
}
return added_cp_entries;
}
static u1* new_bytes_for_lazy_instrumentation(const InstanceKlass* ik,
const ClassFileParser& parser,
jint& size_of_new_bytes,
TRAPS) {
assert(ik != NULL, "invariant");
// If the class already has a clinit method
// we need to take that into account
const Method* clinit_method = ik->class_initializer();
bool untypedEventHandler = false;
const bool register_klass = should_register_klass(ik, untypedEventHandler);
const ClassFileStream* const orig_stream = parser.clone_stream();
const int orig_stream_size = orig_stream->length();
assert(orig_stream->current_offset() == 0, "invariant");
const u2 orig_cp_len = position_stream_after_cp(orig_stream);
assert(orig_cp_len > 0, "invariant");
assert(orig_stream->current_offset() > 0, "invariant");
// Dimension and allocate a working byte buffer
// to be used in building up a modified class [B.
const jint new_buffer_size = extra_stream_bytes + orig_stream_size;
u1* const new_buffer = NEW_RESOURCE_ARRAY_IN_THREAD_RETURN_NULL(THREAD, u1, new_buffer_size);
if (new_buffer == NULL) {
log_error(jfr, system) ("Thread local allocation (native) for " SIZE_FORMAT
" bytes failed in JfrClassAdapter::on_klass_creation", (size_t)new_buffer_size);
return NULL;
}
assert(new_buffer != NULL, "invariant");
// [B wrapped in a big endian writer
JfrBigEndianWriter writer(new_buffer, new_buffer_size);
assert(writer.current_offset() == 0, "invariant");
const u4 orig_access_flag_offset = orig_stream->current_offset();
// Copy original stream from the beginning up to AccessFlags
// This means the original constant pool contents are copied unmodified
writer.bytes(orig_stream->buffer(), orig_access_flag_offset);
assert(writer.is_valid(), "invariant");
assert(writer.current_offset() == (intptr_t)orig_access_flag_offset, "invariant"); // same positions
// Our writer now sits just after the last original constant pool entry.
// I.e. we are in a good position to append new constant pool entries
// This array will contain the resolved indexes
// in order to reference UTF8_INFO's needed
u2 utf8_indexes[NOF_UTF8_SYMBOLS];
// Resolve_utf8_indexes will be conservative in attempting to
// locate an existing UTF8_INFO; it will only append constants
// that is absolutely required
u2 number_of_new_constants =
resolve_utf8_indexes(writer, ik, utf8_indexes, orig_cp_len, clinit_method, register_klass, untypedEventHandler, THREAD);
// UTF8_INFO entries now added to the constant pool
// In order to invoke a method we would need additional
// constants, JVM_CONSTANT_Class, JVM_CONSTANT_NameAndType
// and JVM_CONSTANT_Methodref.
const u2 flr_register_method_ref_index =
register_klass ?
add_flr_register_method_constants(writer,
utf8_indexes,
orig_cp_len,
number_of_new_constants,
THREAD) : invalid_cp_index;
// New constant pool entries added and all UTF8_INFO indexes resolved
// Now update the class file constant_pool_count with an updated count
writer.write_at_offset<u2>(orig_cp_len + number_of_new_constants, 8);
assert(writer.is_valid(), "invariant");
orig_stream->skip_u2_fast(3); // access_flags, this_class_index, super_class_index
const u2 iface_len = orig_stream->get_u2_fast(); // interfaces
orig_stream->skip_u2_fast(iface_len);
const u4 orig_fields_len_offset = orig_stream->current_offset();
// Copy from AccessFlags up to and including interfaces
writer.bytes(orig_stream->buffer() + orig_access_flag_offset,
orig_fields_len_offset - orig_access_flag_offset);
assert(writer.is_valid(), "invariant");
const jlong new_fields_len_offset = writer.current_offset();
const u2 orig_fields_len = position_stream_after_fields(orig_stream);
u4 orig_method_len_offset = orig_stream->current_offset();
// Copy up to and including fields
writer.bytes(orig_stream->buffer() + orig_fields_len_offset, orig_method_len_offset - orig_fields_len_offset);
assert(writer.is_valid(), "invariant");
// We are sitting just after the original number of field_infos
// so this is a position where we can add (append) new field_infos
const u2 number_of_new_fields = add_field_infos(writer, utf8_indexes, untypedEventHandler);
assert(writer.is_valid(), "invariant");
const jlong new_method_len_offset = writer.current_offset();
// Additional field_infos added, update classfile fields_count
writer.write_at_offset<u2>(orig_fields_len + number_of_new_fields, new_fields_len_offset);
assert(writer.is_valid(), "invariant");
// Our current location is now at classfile methods_count
const u2 orig_methods_len = position_stream_after_methods(writer,
orig_stream,
utf8_indexes,
register_klass,
clinit_method,
orig_method_len_offset);
const u4 orig_attributes_count_offset = orig_stream->current_offset();
// Copy existing methods
writer.bytes(orig_stream->buffer() + orig_method_len_offset, orig_attributes_count_offset - orig_method_len_offset);
assert(writer.is_valid(), "invariant");
// We are sitting just after the original number of method_infos
// so this is a position where we can add (append) new method_infos
u2 number_of_new_methods = add_method_infos(writer, utf8_indexes);
// We have just added the new methods.
//
// What about the state of <clinit>?
// We would need to do:
// 1. Nothing (@Registered(false) annotation)
// 2. Build up a new <clinit> - and if the original class already contains a <clinit>,
// merging will be neccessary.
//
if (register_klass) {
insert_clinit_method(ik, parser, writer, orig_cp_len, utf8_indexes, flr_register_method_ref_index, clinit_method, THREAD);
}
number_of_new_methods += clinit_method != NULL ? 0 : register_klass ? 1 : 0;
// Update classfile methods_count
writer.write_at_offset<u2>(orig_methods_len + number_of_new_methods, new_method_len_offset);
assert(writer.is_valid(), "invariant");
// Copy last remaining bytes
writer.bytes(orig_stream->buffer() + orig_attributes_count_offset, orig_stream_size - orig_attributes_count_offset);
assert(writer.is_valid(), "invariant");
assert(writer.current_offset() > orig_stream->length(), "invariant");
size_of_new_bytes = (jint)writer.current_offset();
return new_buffer;
}
static void log_pending_exception(oop throwable) {
assert(throwable != NULL, "invariant");
oop msg = java_lang_Throwable::message(throwable);
if (msg != NULL) {
char* text = java_lang_String::as_utf8_string(msg);
if (text != NULL) {
log_error(jfr, system) ("%s", text);
}
}
}
static bool should_force_instrumentation() {
return !JfrOptionSet::allow_event_retransforms() || JfrEventClassTransformer::is_force_instrumentation();
}
static ClassFileStream* create_new_bytes_for_subklass(const InstanceKlass* ik, const ClassFileParser& parser, Thread* t) {
assert(JdkJfrEvent::is_a(ik), "invariant");
DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(t));
jint size_of_new_bytes = 0;
const u1* new_bytes = new_bytes_for_lazy_instrumentation(ik, parser, size_of_new_bytes, t);
if (new_bytes == NULL) {
return NULL;
}
assert(new_bytes != NULL, "invariant");
assert(size_of_new_bytes > 0, "invariant");
bool force_instrumentation = should_force_instrumentation();
if (Jfr::is_recording() || force_instrumentation) {
jint size_instrumented_data = 0;
unsigned char* instrumented_data = NULL;
const jclass super = (jclass)JNIHandles::make_local(ik->super()->java_mirror());
JfrUpcalls::new_bytes_eager_instrumentation(TRACE_ID(ik),
force_instrumentation,
super,
size_of_new_bytes,
new_bytes,
&size_instrumented_data,
&instrumented_data,
t);
if (t->has_pending_exception()) {
log_pending_exception(t->pending_exception());
t->clear_pending_exception();
return NULL;
}
assert(instrumented_data != NULL, "invariant");
assert(size_instrumented_data > 0, "invariant");
return new ClassFileStream(instrumented_data, size_instrumented_data, NULL, ClassFileStream::verify);
}
return new ClassFileStream(new_bytes, size_of_new_bytes, NULL, ClassFileStream::verify);
}
static bool cache_bytes(InstanceKlass* ik, ClassFileStream* new_stream, InstanceKlass* new_ik, TRAPS) {
assert(ik != NULL, "invariant");
assert(new_ik != NULL, "invariant");
assert(new_ik->name() != NULL, "invariant");
assert(new_stream != NULL, "invariant");
assert(!HAS_PENDING_EXCEPTION, "invariant");
static const bool can_retransform = JfrOptionSet::allow_retransforms();
if (!can_retransform) {
return true;
}
const jint stream_len = new_stream->length();
JvmtiCachedClassFileData* p =
(JvmtiCachedClassFileData*)NEW_C_HEAP_ARRAY_RETURN_NULL(u1, offset_of(JvmtiCachedClassFileData, data) + stream_len, mtInternal);
if (p == NULL) {
log_error(jfr, system)("Allocation using C_HEAP_ARRAY for " SIZE_FORMAT
" bytes failed in JfrClassAdapter::on_klass_creation", (size_t)offset_of(JvmtiCachedClassFileData, data) + stream_len);
return false;
}
p->length = stream_len;
memcpy(p->data, new_stream->buffer(), stream_len);
new_ik->set_cached_class_file(p);
JvmtiCachedClassFileData* const cached_class_data = ik->get_cached_class_file();
if (cached_class_data != NULL) {
os::free(cached_class_data);
ik->set_cached_class_file(NULL);
}
return true;
}
static InstanceKlass* create_new_instance_klass(InstanceKlass* ik, ClassFileStream* stream, TRAPS) {
assert(stream != NULL, "invariant");
ResourceMark rm(THREAD);
ClassLoaderData* const cld = ik->class_loader_data();
Handle pd(THREAD, ik->protection_domain());
Symbol* const class_name = ik->name();
const char* const klass_name = class_name != NULL ? class_name->as_C_string() : "";
ClassFileParser new_parser(stream,
class_name,
cld,
pd,
NULL, // host klass
NULL, // cp_patches
ClassFileParser::INTERNAL, // internal visibility
THREAD);
if (HAS_PENDING_EXCEPTION) {
log_pending_exception(PENDING_EXCEPTION);
CLEAR_PENDING_EXCEPTION;
return NULL;
}
InstanceKlass* const new_ik = new_parser.create_instance_klass(false, THREAD);
if (HAS_PENDING_EXCEPTION) {
log_pending_exception(PENDING_EXCEPTION);
CLEAR_PENDING_EXCEPTION;
return NULL;
}
assert(new_ik != NULL, "invariant");
assert(new_ik->name() != NULL, "invariant");
assert(strncmp(ik->name()->as_C_string(), new_ik->name()->as_C_string(), strlen(ik->name()->as_C_string())) == 0, "invariant");
return cache_bytes(ik, stream, new_ik, THREAD) ? new_ik : NULL;
}
static void rewrite_klass_pointer(InstanceKlass*& ik, InstanceKlass* new_ik, ClassFileParser& parser, TRAPS) {
assert(ik != NULL, "invariant");
assert(new_ik != NULL, "invariant");
assert(new_ik->name() != NULL, "invariant");
assert(JdkJfrEvent::is(new_ik) || JdkJfrEvent::is_subklass(new_ik), "invariant");
assert(!HAS_PENDING_EXCEPTION, "invariant");
// assign original InstanceKlass* back onto "its" parser object for proper destruction
parser.set_klass_to_deallocate(ik);
// now rewrite original pointer to newly created InstanceKlass
ik = new_ik;
}
static bool is_retransforming(const InstanceKlass* ik, TRAPS) {
assert(ik != NULL, "invariant");
assert(JdkJfrEvent::is_a(ik), "invariant");
Symbol* const name = ik->name();
assert(name != NULL, "invariant");
Handle class_loader(THREAD, ik->class_loader());
Handle protection_domain(THREAD, ik->protection_domain());
return SystemDictionary::find(name, class_loader, protection_domain, THREAD) != NULL;
}
// target for JFR_ON_KLASS_CREATION hook
void JfrEventClassTransformer::on_klass_creation(InstanceKlass*& ik, ClassFileParser& parser, TRAPS) {
assert(ik != NULL, "invariant");
if (JdkJfrEvent::is(ik)) {
ResourceMark rm(THREAD);
HandleMark hm(THREAD);
ClassFileStream* new_stream = create_new_bytes_for_event_klass(ik, parser, THREAD);
if (new_stream == NULL) {
log_error(jfr, system)("JfrClassAdapter: unable to create ClassFileStream");
return;
}
assert(new_stream != NULL, "invariant");
InstanceKlass* new_ik = create_new_instance_klass(ik, new_stream, THREAD);
if (new_ik == NULL) {
log_error(jfr, system)("JfrClassAdapter: unable to create InstanceKlass");
return;
}
assert(new_ik != NULL, "invariant");
// We now need to explicitly tag the replaced klass as the jdk.jfr.Event klass
assert(!JdkJfrEvent::is(new_ik), "invariant");
JdkJfrEvent::tag_as(new_ik);
assert(JdkJfrEvent::is(new_ik), "invariant");
rewrite_klass_pointer(ik, new_ik, parser, THREAD);
return;
}
assert(JdkJfrEvent::is_subklass(ik), "invariant");
if (ik->is_abstract() || is_retransforming(ik, THREAD)) {
// abstract and scratch classes are not instrumented
return;
}
ResourceMark rm(THREAD);
HandleMark hm(THREAD);
ClassFileStream* const new_stream = create_new_bytes_for_subklass(ik, parser, THREAD);
if (NULL == new_stream) {
log_error(jfr, system)("JfrClassAdapter: unable to create ClassFileStream");
return;
}
assert(new_stream != NULL, "invariant");
InstanceKlass* new_ik = create_new_instance_klass(ik, new_stream, THREAD);
if (new_ik == NULL) {
log_error(jfr, system)("JfrClassAdapter: unable to create InstanceKlass");
return;
}
assert(new_ik != NULL, "invariant");
// would have been tagged already as a subklass during the normal process of traceid assignment
assert(JdkJfrEvent::is_subklass(new_ik), "invariant");
traceid id = ik->trace_id();
ik->set_trace_id(0);
new_ik->set_trace_id(id);
rewrite_klass_pointer(ik, new_ik, parser, THREAD);
}
static bool _force_instrumentation = false;
void JfrEventClassTransformer::set_force_instrumentation(bool force_instrumentation) {
_force_instrumentation = force_instrumentation;
}
bool JfrEventClassTransformer::is_force_instrumentation() {
return _force_instrumentation;
}