src/hotspot/share/prims/jvmtiClassFileReconstituter.cpp
changeset 47216 71c04702a3d5
parent 46630 75aa3e39d02c
child 49449 ef5d5d343e2a
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/prims/jvmtiClassFileReconstituter.cpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,900 @@
+/*
+ * Copyright (c) 2005, 2017, 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 "interpreter/bytecodeStream.hpp"
+#include "oops/fieldStreams.hpp"
+#include "prims/jvmtiClassFileReconstituter.hpp"
+#include "runtime/signature.hpp"
+#include "utilities/bytes.hpp"
+
+// FIXME: add Deprecated attribute
+// FIXME: fix Synthetic attribute
+// FIXME: per Serguei, add error return handling for ConstantPool::copy_cpool_bytes()
+
+
+// Write the field information portion of ClassFile structure
+// JVMSpec|     u2 fields_count;
+// JVMSpec|     field_info fields[fields_count];
+void JvmtiClassFileReconstituter::write_field_infos() {
+  HandleMark hm(thread());
+  Array<AnnotationArray*>* fields_anno = ik()->fields_annotations();
+  Array<AnnotationArray*>* fields_type_anno = ik()->fields_type_annotations();
+
+  // Compute the real number of Java fields
+  int java_fields = ik()->java_fields_count();
+
+  write_u2(java_fields);
+  for (JavaFieldStream fs(ik()); !fs.done(); fs.next()) {
+    AccessFlags access_flags = fs.access_flags();
+    int name_index = fs.name_index();
+    int signature_index = fs.signature_index();
+    int initial_value_index = fs.initval_index();
+    guarantee(name_index != 0 && signature_index != 0, "bad constant pool index for field");
+    // int offset = ik()->field_offset( index );
+    int generic_signature_index = fs.generic_signature_index();
+    AnnotationArray* anno = fields_anno == NULL ? NULL : fields_anno->at(fs.index());
+    AnnotationArray* type_anno = fields_type_anno == NULL ? NULL : fields_type_anno->at(fs.index());
+
+    // JVMSpec|   field_info {
+    // JVMSpec|         u2 access_flags;
+    // JVMSpec|         u2 name_index;
+    // JVMSpec|         u2 descriptor_index;
+    // JVMSpec|         u2 attributes_count;
+    // JVMSpec|         attribute_info attributes[attributes_count];
+    // JVMSpec|   }
+
+    write_u2(access_flags.as_int() & JVM_RECOGNIZED_FIELD_MODIFIERS);
+    write_u2(name_index);
+    write_u2(signature_index);
+    int attr_count = 0;
+    if (initial_value_index != 0) {
+      ++attr_count;
+    }
+    if (access_flags.is_synthetic()) {
+      // ++attr_count;
+    }
+    if (generic_signature_index != 0) {
+      ++attr_count;
+    }
+    if (anno != NULL) {
+      ++attr_count;     // has RuntimeVisibleAnnotations attribute
+    }
+    if (type_anno != NULL) {
+      ++attr_count;     // has RuntimeVisibleTypeAnnotations attribute
+    }
+
+    write_u2(attr_count);
+
+    if (initial_value_index != 0) {
+      write_attribute_name_index("ConstantValue");
+      write_u4(2); //length always 2
+      write_u2(initial_value_index);
+    }
+    if (access_flags.is_synthetic()) {
+      // write_synthetic_attribute();
+    }
+    if (generic_signature_index != 0) {
+      write_signature_attribute(generic_signature_index);
+    }
+    if (anno != NULL) {
+      write_annotations_attribute("RuntimeVisibleAnnotations", anno);
+    }
+    if (type_anno != NULL) {
+      write_annotations_attribute("RuntimeVisibleTypeAnnotations", type_anno);
+    }
+  }
+}
+
+// Write Code attribute
+// JVMSpec|   Code_attribute {
+// JVMSpec|     u2 attribute_name_index;
+// JVMSpec|     u4 attribute_length;
+// JVMSpec|     u2 max_stack;
+// JVMSpec|     u2 max_locals;
+// JVMSpec|     u4 code_length;
+// JVMSpec|     u1 code[code_length];
+// JVMSpec|     u2 exception_table_length;
+// JVMSpec|     {       u2 start_pc;
+// JVMSpec|             u2 end_pc;
+// JVMSpec|             u2  handler_pc;
+// JVMSpec|             u2  catch_type;
+// JVMSpec|     }       exception_table[exception_table_length];
+// JVMSpec|     u2 attributes_count;
+// JVMSpec|     attribute_info attributes[attributes_count];
+// JVMSpec|   }
+void JvmtiClassFileReconstituter::write_code_attribute(const methodHandle& method) {
+  ConstMethod* const_method = method->constMethod();
+  u2 line_num_cnt = 0;
+  int stackmap_len = 0;
+  int local_variable_table_length = 0;
+  int local_variable_type_table_length = 0;
+
+  // compute number and length of attributes
+  int attr_count = 0;
+  int attr_size = 0;
+  if (const_method->has_linenumber_table()) {
+    line_num_cnt = line_number_table_entries(method);
+    if (line_num_cnt != 0) {
+      ++attr_count;
+      // Compute the complete size of the line number table attribute:
+      //      LineNumberTable_attribute {
+      //        u2 attribute_name_index;
+      //        u4 attribute_length;
+      //        u2 line_number_table_length;
+      //        {  u2 start_pc;
+      //           u2 line_number;
+      //        } line_number_table[line_number_table_length];
+      //      }
+      attr_size += 2 + 4 + 2 + line_num_cnt * (2 + 2);
+    }
+  }
+  if (method->has_stackmap_table()) {
+    stackmap_len = method->stackmap_data()->length();
+    if (stackmap_len != 0) {
+      ++attr_count;
+      // Compute the  size of the stack map table attribute (VM stores raw):
+      //      StackMapTable_attribute {
+      //        u2 attribute_name_index;
+      //        u4 attribute_length;
+      //        u2 number_of_entries;
+      //        stack_map_frame_entries[number_of_entries];
+      //      }
+      attr_size += 2 + 4 + stackmap_len;
+    }
+  }
+  if (method->has_localvariable_table()) {
+    local_variable_table_length = method->localvariable_table_length();
+    if (local_variable_table_length != 0) {
+      ++attr_count;
+      // Compute the size of the local variable table attribute (VM stores raw):
+      // LocalVariableTable_attribute {
+      //   u2 attribute_name_index;
+      //   u4 attribute_length;
+      //   u2 local_variable_table_length;
+      //   {
+      //     u2 start_pc;
+      //     u2 length;
+      //     u2 name_index;
+      //     u2 descriptor_index;
+      //     u2 index;
+      //   }
+      attr_size += 2 + 4 + 2 + local_variable_table_length * (2 + 2 + 2 + 2 + 2);
+
+      // Local variables with generic signatures must have LVTT entries
+      LocalVariableTableElement *elem = method->localvariable_table_start();
+      for (int idx = 0; idx < local_variable_table_length; idx++) {
+        if (elem[idx].signature_cp_index != 0) {
+          local_variable_type_table_length++;
+        }
+      }
+
+      if (local_variable_type_table_length != 0) {
+        ++attr_count;
+        // Compute the size of the local variable type table attribute (VM stores raw):
+        // LocalVariableTypeTable_attribute {
+        //   u2 attribute_name_index;
+        //   u4 attribute_length;
+        //   u2 local_variable_type_table_length;
+        //   {
+        //     u2 start_pc;
+        //     u2 length;
+        //     u2 name_index;
+        //     u2 signature_index;
+        //     u2 index;
+        //   }
+        attr_size += 2 + 4 + 2 + local_variable_type_table_length * (2 + 2 + 2 + 2 + 2);
+      }
+    }
+  }
+
+  ExceptionTable exception_table(method());
+  int exception_table_length = exception_table.length();
+  int code_size = const_method->code_size();
+  int size =
+    2+2+4 +                                // max_stack, max_locals, code_length
+    code_size +                            // code
+    2 +                                    // exception_table_length
+    (2+2+2+2) * exception_table_length +   // exception_table
+    2 +                                    // attributes_count
+    attr_size;                             // attributes
+
+  write_attribute_name_index("Code");
+  write_u4(size);
+  write_u2(method->verifier_max_stack());
+  write_u2(method->max_locals());
+  write_u4(code_size);
+  copy_bytecodes(method, (unsigned char*)writeable_address(code_size));
+  write_u2(exception_table_length);
+  for (int index = 0; index < exception_table_length; index++) {
+    write_u2(exception_table.start_pc(index));
+    write_u2(exception_table.end_pc(index));
+    write_u2(exception_table.handler_pc(index));
+    write_u2(exception_table.catch_type_index(index));
+  }
+  write_u2(attr_count);
+  if (line_num_cnt != 0) {
+    write_line_number_table_attribute(method, line_num_cnt);
+  }
+  if (stackmap_len != 0) {
+    write_stackmap_table_attribute(method, stackmap_len);
+  }
+  if (local_variable_table_length != 0) {
+    write_local_variable_table_attribute(method, local_variable_table_length);
+  }
+  if (local_variable_type_table_length != 0) {
+    write_local_variable_type_table_attribute(method, local_variable_type_table_length);
+  }
+}
+
+// Write Exceptions attribute
+// JVMSpec|   Exceptions_attribute {
+// JVMSpec|     u2 attribute_name_index;
+// JVMSpec|     u4 attribute_length;
+// JVMSpec|     u2 number_of_exceptions;
+// JVMSpec|     u2 exception_index_table[number_of_exceptions];
+// JVMSpec|   }
+void JvmtiClassFileReconstituter::write_exceptions_attribute(ConstMethod* const_method) {
+  CheckedExceptionElement* checked_exceptions = const_method->checked_exceptions_start();
+  int checked_exceptions_length = const_method->checked_exceptions_length();
+  int size =
+    2 +                                    // number_of_exceptions
+    2 * checked_exceptions_length;         // exception_index_table
+
+  write_attribute_name_index("Exceptions");
+  write_u4(size);
+  write_u2(checked_exceptions_length);
+  for (int index = 0; index < checked_exceptions_length; index++) {
+    write_u2(checked_exceptions[index].class_cp_index);
+  }
+}
+
+// Write SourceFile attribute
+// JVMSpec|   SourceFile_attribute {
+// JVMSpec|     u2 attribute_name_index;
+// JVMSpec|     u4 attribute_length;
+// JVMSpec|     u2 sourcefile_index;
+// JVMSpec|   }
+void JvmtiClassFileReconstituter::write_source_file_attribute() {
+  assert(ik()->source_file_name() != NULL, "caller must check");
+
+  write_attribute_name_index("SourceFile");
+  write_u4(2);  // always length 2
+  write_u2(symbol_to_cpool_index(ik()->source_file_name()));
+}
+
+// Write SourceDebugExtension attribute
+// JSR45|   SourceDebugExtension_attribute {
+// JSR45|       u2 attribute_name_index;
+// JSR45|       u4 attribute_length;
+// JSR45|       u1 debug_extension[attribute_length];
+// JSR45|   }
+void JvmtiClassFileReconstituter::write_source_debug_extension_attribute() {
+  assert(ik()->source_debug_extension() != NULL, "caller must check");
+
+  write_attribute_name_index("SourceDebugExtension");
+  int len = (int)strlen(ik()->source_debug_extension());
+  write_u4(len);
+  u1* ext = (u1*)ik()->source_debug_extension();
+  for (int i=0; i<len; i++) {
+    write_u1(ext[i]);
+  }
+}
+
+// Write (generic) Signature attribute
+// JVMSpec|   Signature_attribute {
+// JVMSpec|     u2 attribute_name_index;
+// JVMSpec|     u4 attribute_length;
+// JVMSpec|     u2 signature_index;
+// JVMSpec|   }
+void JvmtiClassFileReconstituter::write_signature_attribute(u2 generic_signature_index) {
+  write_attribute_name_index("Signature");
+  write_u4(2);  // always length 2
+  write_u2(generic_signature_index);
+}
+
+// Compute the number of entries in the InnerClasses attribute
+u2 JvmtiClassFileReconstituter::inner_classes_attribute_length() {
+  InnerClassesIterator iter(ik());
+  return iter.length();
+}
+
+// Write an annotation attribute.  The VM stores them in raw form, so all we need
+// to do is add the attrubute name and fill in the length.
+// JSR202|   *Annotations_attribute {
+// JSR202|     u2 attribute_name_index;
+// JSR202|     u4 attribute_length;
+// JSR202|     ...
+// JSR202|   }
+void JvmtiClassFileReconstituter::write_annotations_attribute(const char* attr_name,
+                                                              AnnotationArray* annos) {
+  u4 length = annos->length();
+  write_attribute_name_index(attr_name);
+  write_u4(length);
+  memcpy(writeable_address(length), annos->adr_at(0), length);
+}
+
+//  BootstrapMethods_attribute {
+//    u2 attribute_name_index;
+//    u4 attribute_length;
+//    u2 num_bootstrap_methods;
+//    {   u2 bootstrap_method_ref;
+//        u2 num_bootstrap_arguments;
+//        u2 bootstrap_arguments[num_bootstrap_arguments];
+//    } bootstrap_methods[num_bootstrap_methods];
+//  }
+void JvmtiClassFileReconstituter::write_bootstrapmethod_attribute() {
+  Array<u2>* operands = cpool()->operands();
+  write_attribute_name_index("BootstrapMethods");
+  int num_bootstrap_methods = ConstantPool::operand_array_length(operands);
+
+  // calculate length of attribute
+  int length = sizeof(u2); // num_bootstrap_methods
+  for (int n = 0; n < num_bootstrap_methods; n++) {
+    u2 num_bootstrap_arguments = cpool()->operand_argument_count_at(n);
+    length += sizeof(u2); // bootstrap_method_ref
+    length += sizeof(u2); // num_bootstrap_arguments
+    length += sizeof(u2) * num_bootstrap_arguments; // bootstrap_arguments[num_bootstrap_arguments]
+  }
+  write_u4(length);
+
+  // write attribute
+  write_u2(num_bootstrap_methods);
+  for (int n = 0; n < num_bootstrap_methods; n++) {
+    u2 bootstrap_method_ref = cpool()->operand_bootstrap_method_ref_index_at(n);
+    u2 num_bootstrap_arguments = cpool()->operand_argument_count_at(n);
+    write_u2(bootstrap_method_ref);
+    write_u2(num_bootstrap_arguments);
+    for (int arg = 0; arg < num_bootstrap_arguments; arg++) {
+      u2 bootstrap_argument = cpool()->operand_argument_index_at(n, arg);
+      write_u2(bootstrap_argument);
+    }
+  }
+}
+
+
+// Write InnerClasses attribute
+// JVMSpec|   InnerClasses_attribute {
+// JVMSpec|     u2 attribute_name_index;
+// JVMSpec|     u4 attribute_length;
+// JVMSpec|     u2 number_of_classes;
+// JVMSpec|     {  u2 inner_class_info_index;
+// JVMSpec|        u2 outer_class_info_index;
+// JVMSpec|        u2 inner_name_index;
+// JVMSpec|        u2 inner_class_access_flags;
+// JVMSpec|     } classes[number_of_classes];
+// JVMSpec|   }
+void JvmtiClassFileReconstituter::write_inner_classes_attribute(int length) {
+  InnerClassesIterator iter(ik());
+  guarantee(iter.length() != 0 && iter.length() == length,
+            "caller must check");
+  u2 entry_count = length / InstanceKlass::inner_class_next_offset;
+  u4 size = 2 + entry_count * (2+2+2+2);
+
+  write_attribute_name_index("InnerClasses");
+  write_u4(size);
+  write_u2(entry_count);
+  for (; !iter.done(); iter.next()) {
+    write_u2(iter.inner_class_info_index());
+    write_u2(iter.outer_class_info_index());
+    write_u2(iter.inner_name_index());
+    write_u2(iter.inner_access_flags());
+  }
+}
+
+// Write Synthetic attribute
+// JVMSpec|   Synthetic_attribute {
+// JVMSpec|     u2 attribute_name_index;
+// JVMSpec|     u4 attribute_length;
+// JVMSpec|   }
+void JvmtiClassFileReconstituter::write_synthetic_attribute() {
+  write_attribute_name_index("Synthetic");
+  write_u4(0); //length always zero
+}
+
+// Compute size of LineNumberTable
+u2 JvmtiClassFileReconstituter::line_number_table_entries(const methodHandle& method) {
+  // The line number table is compressed so we don't know how big it is until decompressed.
+  // Decompression is really fast so we just do it twice.
+  u2 num_entries = 0;
+  CompressedLineNumberReadStream stream(method->compressed_linenumber_table());
+  while (stream.read_pair()) {
+    num_entries++;
+  }
+  return num_entries;
+}
+
+// Write LineNumberTable attribute
+// JVMSpec|   LineNumberTable_attribute {
+// JVMSpec|     u2 attribute_name_index;
+// JVMSpec|     u4 attribute_length;
+// JVMSpec|     u2 line_number_table_length;
+// JVMSpec|     {  u2 start_pc;
+// JVMSpec|        u2 line_number;
+// JVMSpec|     } line_number_table[line_number_table_length];
+// JVMSpec|   }
+void JvmtiClassFileReconstituter::write_line_number_table_attribute(const methodHandle& method,
+                                                                    u2 num_entries) {
+
+  write_attribute_name_index("LineNumberTable");
+  write_u4(2 + num_entries * (2 + 2));
+  write_u2(num_entries);
+
+  CompressedLineNumberReadStream stream(method->compressed_linenumber_table());
+  while (stream.read_pair()) {
+    write_u2(stream.bci());
+    write_u2(stream.line());
+  }
+}
+
+// Write LocalVariableTable attribute
+// JVMSpec|   LocalVariableTable_attribute {
+// JVMSpec|     u2 attribute_name_index;
+// JVMSpec|     u4 attribute_length;
+// JVMSpec|     u2 local_variable_table_length;
+// JVMSpec|     {  u2 start_pc;
+// JVMSpec|       u2 length;
+// JVMSpec|       u2 name_index;
+// JVMSpec|       u2 descriptor_index;
+// JVMSpec|       u2 index;
+// JVMSpec|     } local_variable_table[local_variable_table_length];
+// JVMSpec|   }
+void JvmtiClassFileReconstituter::write_local_variable_table_attribute(const methodHandle& method, u2 num_entries) {
+    write_attribute_name_index("LocalVariableTable");
+    write_u4(2 + num_entries * (2 + 2 + 2 + 2 + 2));
+    write_u2(num_entries);
+
+    assert(method->localvariable_table_length() == num_entries, "just checking");
+
+    LocalVariableTableElement *elem = method->localvariable_table_start();
+    for (int j=0; j<method->localvariable_table_length(); j++) {
+      write_u2(elem->start_bci);
+      write_u2(elem->length);
+      write_u2(elem->name_cp_index);
+      write_u2(elem->descriptor_cp_index);
+      write_u2(elem->slot);
+      elem++;
+    }
+}
+
+// Write LocalVariableTypeTable attribute
+// JVMSpec|   LocalVariableTypeTable_attribute {
+// JVMSpec|     u2 attribute_name_index;
+// JVMSpec|     u4 attribute_length;
+// JVMSpec|     u2 local_variable_type_table_length;
+// JVMSpec|     { u2 start_pc;
+// JVMSpec|       u2 length;
+// JVMSpec|       u2 name_index;
+// JVMSpec|       u2 signature_index;
+// JVMSpec|       u2 index;
+// JVMSpec|     } local_variable_type_table[local_variable_type_table_length];
+// JVMSpec|   }
+void JvmtiClassFileReconstituter::write_local_variable_type_table_attribute(const methodHandle& method, u2 num_entries) {
+    write_attribute_name_index("LocalVariableTypeTable");
+    write_u4(2 + num_entries * (2 + 2 + 2 + 2 + 2));
+    write_u2(num_entries);
+
+    LocalVariableTableElement *elem = method->localvariable_table_start();
+    for (int j=0; j<method->localvariable_table_length(); j++) {
+      if (elem->signature_cp_index > 0) {
+        // Local variable has a generic signature - write LVTT attribute entry
+        write_u2(elem->start_bci);
+        write_u2(elem->length);
+        write_u2(elem->name_cp_index);
+        write_u2(elem->signature_cp_index);
+        write_u2(elem->slot);
+        num_entries--;
+      }
+      elem++;
+    }
+    assert(num_entries == 0, "just checking");
+}
+
+// Write stack map table attribute
+// JSR-202|   StackMapTable_attribute {
+// JSR-202|     u2 attribute_name_index;
+// JSR-202|     u4 attribute_length;
+// JSR-202|     u2 number_of_entries;
+// JSR-202|     stack_map_frame_entries[number_of_entries];
+// JSR-202|   }
+void JvmtiClassFileReconstituter::write_stackmap_table_attribute(const methodHandle& method,
+                                                                 int stackmap_len) {
+
+  write_attribute_name_index("StackMapTable");
+  write_u4(stackmap_len);
+  memcpy(
+    writeable_address(stackmap_len),
+    (void*)(method->stackmap_data()->adr_at(0)),
+    stackmap_len);
+}
+
+// Write one method_info structure
+// JVMSpec|   method_info {
+// JVMSpec|     u2 access_flags;
+// JVMSpec|     u2 name_index;
+// JVMSpec|     u2 descriptor_index;
+// JVMSpec|     u2 attributes_count;
+// JVMSpec|     attribute_info attributes[attributes_count];
+// JVMSpec|   }
+void JvmtiClassFileReconstituter::write_method_info(const methodHandle& method) {
+  AccessFlags access_flags = method->access_flags();
+  ConstMethod* const_method = method->constMethod();
+  u2 generic_signature_index = const_method->generic_signature_index();
+  AnnotationArray* anno = method->annotations();
+  AnnotationArray* param_anno = method->parameter_annotations();
+  AnnotationArray* default_anno = method->annotation_default();
+  AnnotationArray* type_anno = method->type_annotations();
+
+  // skip generated default interface methods
+  if (method->is_overpass()) {
+    return;
+  }
+
+  write_u2(access_flags.get_flags() & JVM_RECOGNIZED_METHOD_MODIFIERS);
+  write_u2(const_method->name_index());
+  write_u2(const_method->signature_index());
+
+  // write attributes in the same order javac does, so we can test with byte for
+  // byte comparison
+  int attr_count = 0;
+  if (const_method->code_size() != 0) {
+    ++attr_count;     // has Code attribute
+  }
+  if (const_method->has_checked_exceptions()) {
+    ++attr_count;     // has Exceptions attribute
+  }
+  if (default_anno != NULL) {
+    ++attr_count;     // has AnnotationDefault attribute
+  }
+  // Deprecated attribute would go here
+  if (access_flags.is_synthetic()) { // FIXME
+    // ++attr_count;
+  }
+  if (generic_signature_index != 0) {
+    ++attr_count;
+  }
+  if (anno != NULL) {
+    ++attr_count;     // has RuntimeVisibleAnnotations attribute
+  }
+  if (param_anno != NULL) {
+    ++attr_count;     // has RuntimeVisibleParameterAnnotations attribute
+  }
+  if (type_anno != NULL) {
+    ++attr_count;     // has RuntimeVisibleTypeAnnotations attribute
+  }
+
+  write_u2(attr_count);
+  if (const_method->code_size() > 0) {
+    write_code_attribute(method);
+  }
+  if (const_method->has_checked_exceptions()) {
+    write_exceptions_attribute(const_method);
+  }
+  if (default_anno != NULL) {
+    write_annotations_attribute("AnnotationDefault", default_anno);
+  }
+  // Deprecated attribute would go here
+  if (access_flags.is_synthetic()) {
+    // write_synthetic_attribute();
+  }
+  if (generic_signature_index != 0) {
+    write_signature_attribute(generic_signature_index);
+  }
+  if (anno != NULL) {
+    write_annotations_attribute("RuntimeVisibleAnnotations", anno);
+  }
+  if (param_anno != NULL) {
+    write_annotations_attribute("RuntimeVisibleParameterAnnotations", param_anno);
+  }
+  if (type_anno != NULL) {
+    write_annotations_attribute("RuntimeVisibleTypeAnnotations", type_anno);
+  }
+}
+
+// Write the class attributes portion of ClassFile structure
+// JVMSpec|     u2 attributes_count;
+// JVMSpec|     attribute_info attributes[attributes_count];
+void JvmtiClassFileReconstituter::write_class_attributes() {
+  u2 inner_classes_length = inner_classes_attribute_length();
+  Symbol* generic_signature = ik()->generic_signature();
+  AnnotationArray* anno = ik()->class_annotations();
+  AnnotationArray* type_anno = ik()->class_type_annotations();
+
+  int attr_count = 0;
+  if (generic_signature != NULL) {
+    ++attr_count;
+  }
+  if (ik()->source_file_name() != NULL) {
+    ++attr_count;
+  }
+  if (ik()->source_debug_extension() != NULL) {
+    ++attr_count;
+  }
+  if (inner_classes_length > 0) {
+    ++attr_count;
+  }
+  if (anno != NULL) {
+    ++attr_count;     // has RuntimeVisibleAnnotations attribute
+  }
+  if (type_anno != NULL) {
+    ++attr_count;     // has RuntimeVisibleTypeAnnotations attribute
+  }
+  if (cpool()->operands() != NULL) {
+    ++attr_count;
+  }
+
+  write_u2(attr_count);
+
+  if (generic_signature != NULL) {
+    write_signature_attribute(symbol_to_cpool_index(generic_signature));
+  }
+  if (ik()->source_file_name() != NULL) {
+    write_source_file_attribute();
+  }
+  if (ik()->source_debug_extension() != NULL) {
+    write_source_debug_extension_attribute();
+  }
+  if (inner_classes_length > 0) {
+    write_inner_classes_attribute(inner_classes_length);
+  }
+  if (anno != NULL) {
+    write_annotations_attribute("RuntimeVisibleAnnotations", anno);
+  }
+  if (type_anno != NULL) {
+    write_annotations_attribute("RuntimeVisibleTypeAnnotations", type_anno);
+  }
+  if (cpool()->operands() != NULL) {
+    write_bootstrapmethod_attribute();
+  }
+}
+
+// Write the method information portion of ClassFile structure
+// JVMSpec|     u2 methods_count;
+// JVMSpec|     method_info methods[methods_count];
+void JvmtiClassFileReconstituter::write_method_infos() {
+  HandleMark hm(thread());
+  Array<Method*>* methods = ik()->methods();
+  int num_methods = methods->length();
+  int num_overpass = 0;
+
+  // count the generated default interface methods
+  // these will not be re-created by write_method_info
+  // and should not be included in the total count
+  for (int index = 0; index < num_methods; index++) {
+    Method* method = methods->at(index);
+    if (method->is_overpass()) {
+      num_overpass++;
+    }
+  }
+
+  write_u2(num_methods - num_overpass);
+  if (JvmtiExport::can_maintain_original_method_order()) {
+    int index;
+    int original_index;
+    intArray method_order(num_methods, num_methods, 0);
+
+    // invert the method order mapping
+    for (index = 0; index < num_methods; index++) {
+      original_index = ik()->method_ordering()->at(index);
+      assert(original_index >= 0 && original_index < num_methods,
+             "invalid original method index");
+      method_order.at_put(original_index, index);
+    }
+
+    // write in original order
+    for (original_index = 0; original_index < num_methods; original_index++) {
+      index = method_order.at(original_index);
+      methodHandle method(thread(), methods->at(index));
+      write_method_info(method);
+    }
+  } else {
+    // method order not preserved just dump the method infos
+    for (int index = 0; index < num_methods; index++) {
+      methodHandle method(thread(), methods->at(index));
+      write_method_info(method);
+    }
+  }
+}
+
+void JvmtiClassFileReconstituter::write_class_file_format() {
+  ReallocMark();
+
+  // JVMSpec|   ClassFile {
+  // JVMSpec|           u4 magic;
+  write_u4(0xCAFEBABE);
+
+  // JVMSpec|           u2 minor_version;
+  // JVMSpec|           u2 major_version;
+  write_u2(ik()->minor_version());
+  u2 major = ik()->major_version();
+  write_u2(major);
+
+  // JVMSpec|           u2 constant_pool_count;
+  // JVMSpec|           cp_info constant_pool[constant_pool_count-1];
+  write_u2(cpool()->length());
+  copy_cpool_bytes(writeable_address(cpool_size()));
+
+  // JVMSpec|           u2 access_flags;
+  write_u2(ik()->access_flags().get_flags() & JVM_RECOGNIZED_CLASS_MODIFIERS);
+
+  // JVMSpec|           u2 this_class;
+  // JVMSpec|           u2 super_class;
+  write_u2(class_symbol_to_cpool_index(ik()->name()));
+  Klass* super_class = ik()->super();
+  write_u2(super_class == NULL? 0 :  // zero for java.lang.Object
+                class_symbol_to_cpool_index(super_class->name()));
+
+  // JVMSpec|           u2 interfaces_count;
+  // JVMSpec|           u2 interfaces[interfaces_count];
+  Array<Klass*>* interfaces =  ik()->local_interfaces();
+  int num_interfaces = interfaces->length();
+  write_u2(num_interfaces);
+  for (int index = 0; index < num_interfaces; index++) {
+    HandleMark hm(thread());
+    InstanceKlass* iik = InstanceKlass::cast(interfaces->at(index));
+    write_u2(class_symbol_to_cpool_index(iik->name()));
+  }
+
+  // JVMSpec|           u2 fields_count;
+  // JVMSpec|           field_info fields[fields_count];
+  write_field_infos();
+
+  // JVMSpec|           u2 methods_count;
+  // JVMSpec|           method_info methods[methods_count];
+  write_method_infos();
+
+  // JVMSpec|           u2 attributes_count;
+  // JVMSpec|           attribute_info attributes[attributes_count];
+  // JVMSpec|   } /* end ClassFile 8?
+  write_class_attributes();
+}
+
+address JvmtiClassFileReconstituter::writeable_address(size_t size) {
+  size_t used_size = _buffer_ptr - _buffer;
+  if (size + used_size >= _buffer_size) {
+    // compute the new buffer size: must be at least twice as big as before
+    // plus whatever new is being used; then convert to nice clean block boundary
+    size_t new_buffer_size = (size + _buffer_size*2 + 1) / initial_buffer_size
+                                                         * initial_buffer_size;
+
+    // VM goes belly-up if the memory isn't available, so cannot do OOM processing
+    _buffer = REALLOC_RESOURCE_ARRAY(u1, _buffer, _buffer_size, new_buffer_size);
+    _buffer_size = new_buffer_size;
+    _buffer_ptr = _buffer + used_size;
+  }
+  u1* ret_ptr = _buffer_ptr;
+  _buffer_ptr += size;
+  return ret_ptr;
+}
+
+void JvmtiClassFileReconstituter::write_attribute_name_index(const char* name) {
+  TempNewSymbol sym = SymbolTable::probe(name, (int)strlen(name));
+  assert(sym != NULL, "attribute name symbol not found");
+  u2 attr_name_index = symbol_to_cpool_index(sym);
+  assert(attr_name_index != 0, "attribute name symbol not in constant pool");
+  write_u2(attr_name_index);
+}
+
+void JvmtiClassFileReconstituter::write_u1(u1 x) {
+  *writeable_address(1) = x;
+}
+
+void JvmtiClassFileReconstituter::write_u2(u2 x) {
+  Bytes::put_Java_u2(writeable_address(2), x);
+}
+
+void JvmtiClassFileReconstituter::write_u4(u4 x) {
+  Bytes::put_Java_u4(writeable_address(4), x);
+}
+
+void JvmtiClassFileReconstituter::write_u8(u8 x) {
+  Bytes::put_Java_u8(writeable_address(8), x);
+}
+
+void JvmtiClassFileReconstituter::copy_bytecodes(const methodHandle& mh,
+                                                 unsigned char* bytecodes) {
+  // use a BytecodeStream to iterate over the bytecodes. JVM/fast bytecodes
+  // and the breakpoint bytecode are converted to their original bytecodes.
+
+  BytecodeStream bs(mh);
+
+  unsigned char* p = bytecodes;
+  Bytecodes::Code code;
+  bool is_rewritten = mh->method_holder()->is_rewritten();
+
+  while ((code = bs.next()) >= 0) {
+    assert(Bytecodes::is_java_code(code), "sanity check");
+    assert(code != Bytecodes::_breakpoint, "sanity check");
+
+    // length of bytecode (mnemonic + operands)
+    address bcp = bs.bcp();
+    int     len = bs.instruction_size();
+    assert(len > 0, "length must be > 0");
+
+    // copy the bytecodes
+    *p = (unsigned char) (bs.is_wide()? Bytecodes::_wide : code);
+    if (len > 1) {
+      memcpy(p+1, bcp+1, len-1);
+    }
+
+    // During linking the get/put and invoke instructions are rewritten
+    // with an index into the constant pool cache. The original constant
+    // pool index must be returned to caller.  Rewrite the index.
+    if (is_rewritten && len > 1) {
+      bool is_wide = false;
+      switch (code) {
+      case Bytecodes::_getstatic       :  // fall through
+      case Bytecodes::_putstatic       :  // fall through
+      case Bytecodes::_getfield        :  // fall through
+      case Bytecodes::_putfield        :  // fall through
+      case Bytecodes::_invokevirtual   :  // fall through
+      case Bytecodes::_invokespecial   :  // fall through
+      case Bytecodes::_invokestatic    :  // fall through
+      case Bytecodes::_invokedynamic   :  // fall through
+      case Bytecodes::_invokeinterface : {
+        assert(len == 3 ||
+               (code == Bytecodes::_invokeinterface && len == 5) ||
+               (code == Bytecodes::_invokedynamic   && len == 5),
+               "sanity check");
+
+        int cpci = Bytes::get_native_u2(bcp+1);
+        bool is_invokedynamic = (code == Bytecodes::_invokedynamic);
+        ConstantPoolCacheEntry* entry;
+        if (is_invokedynamic) {
+          cpci = Bytes::get_native_u4(bcp+1);
+          entry = mh->constants()->invokedynamic_cp_cache_entry_at(cpci);
+        } else {
+        // cache cannot be pre-fetched since some classes won't have it yet
+          entry = mh->constants()->cache()->entry_at(cpci);
+        }
+        int i = entry->constant_pool_index();
+        assert(i < mh->constants()->length(), "sanity check");
+        Bytes::put_Java_u2((address)(p+1), (u2)i);     // java byte ordering
+        if (is_invokedynamic)  *(p+3) = *(p+4) = 0;
+        break;
+      }
+      case Bytecodes::_ldc_w:
+        is_wide = true; // fall through
+      case Bytecodes::_ldc: {
+        if (bs.raw_code() == Bytecodes::_fast_aldc || bs.raw_code() == Bytecodes::_fast_aldc_w) {
+          int cpci = is_wide ? Bytes::get_native_u2(bcp+1) : (u1)(*(bcp+1));
+          int i = mh->constants()->object_to_cp_index(cpci);
+          assert(i < mh->constants()->length(), "sanity check");
+          if (is_wide) {
+            Bytes::put_Java_u2((address)(p+1), (u2)i);     // java byte ordering
+          } else {
+            *(p+1) = (u1)i;
+          }
+        }
+        break;
+        }
+      default:
+        break;
+      }
+    }
+
+    p += len;
+  }
+}