1 /*
   2  * Copyright (c) 2005, 2025, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "classfile/symbolTable.hpp"
  26 #include "classfile/vmClasses.hpp"
  27 #include "interpreter/bytecodeStream.hpp"
  28 #include "memory/universe.hpp"
  29 #include "oops/constantPool.inline.hpp"
  30 #include "oops/fieldStreams.inline.hpp"
  31 #include "oops/instanceKlass.inline.hpp"
  32 #include "oops/recordComponent.hpp"
  33 #include "prims/jvmtiClassFileReconstituter.hpp"
  34 #include "runtime/handles.inline.hpp"
  35 #include "runtime/signature.hpp"
  36 #include "utilities/bytes.hpp"
  37 #include "utilities/checkedCast.hpp"
  38 
  39 // FIXME: add Deprecated attribute
  40 // FIXME: fix Synthetic attribute
  41 // FIXME: per Serguei, add error return handling for ConstantPool::copy_cpool_bytes()
  42 
  43 JvmtiConstantPoolReconstituter::JvmtiConstantPoolReconstituter(InstanceKlass* ik) {
  44   set_error(JVMTI_ERROR_NONE);
  45   _ik = ik;
  46   _cpool = constantPoolHandle(Thread::current(), ik->constants());
  47   _symmap = new ConstantPool::SymbolHash();
  48   _classmap = new ConstantPool::SymbolHash();
  49   _cpool_size = _cpool->hash_entries_to(_symmap, _classmap);
  50   if (_cpool_size == 0) {
  51     set_error(JVMTI_ERROR_OUT_OF_MEMORY);
  52   } else if (_cpool_size < 0) {
  53     set_error(JVMTI_ERROR_INTERNAL);
  54   }
  55 }
  56 
  57 // Write the field information portion of ClassFile structure
  58 // JVMSpec|     u2 fields_count;
  59 // JVMSpec|     field_info fields[fields_count];
  60 void JvmtiClassFileReconstituter::write_field_infos() {
  61   HandleMark hm(thread());
  62   Array<AnnotationArray*>* fields_anno = ik()->fields_annotations();
  63   Array<AnnotationArray*>* fields_type_anno = ik()->fields_type_annotations();
  64 
  65   // Compute the real number of Java fields
  66   int java_fields = ik()->java_fields_count();
  67 
  68   write_u2(checked_cast<u2>(java_fields));
  69   for (JavaFieldStream fs(ik()); !fs.done(); fs.next()) {
  70     AccessFlags access_flags = fs.access_flags();
  71     u2 name_index = fs.name_index();
  72     u2 signature_index = fs.signature_index();
  73     u2 initial_value_index = fs.initval_index();
  74     guarantee(name_index != 0 && signature_index != 0, "bad constant pool index for field");
  75     // int offset = ik()->field_offset( index );
  76     u2 generic_signature_index = fs.generic_signature_index();
  77     AnnotationArray* anno = fields_anno == nullptr ? nullptr : fields_anno->at(fs.index());
  78     AnnotationArray* type_anno = fields_type_anno == nullptr ? nullptr : fields_type_anno->at(fs.index());
  79 
  80     // JVMSpec|   field_info {
  81     // JVMSpec|         u2 access_flags;
  82     // JVMSpec|         u2 name_index;
  83     // JVMSpec|         u2 descriptor_index;
  84     // JVMSpec|         u2 attributes_count;
  85     // JVMSpec|         attribute_info attributes[attributes_count];
  86     // JVMSpec|   }
  87 
  88     write_u2(access_flags.as_field_flags());
  89     write_u2(name_index);
  90     write_u2(signature_index);
  91     u2 attr_count = 0;
  92     if (initial_value_index != 0) {
  93       ++attr_count;
  94     }
  95     if (access_flags.is_synthetic()) {
  96       // ++attr_count;
  97     }
  98     if (generic_signature_index != 0) {
  99       ++attr_count;
 100     }
 101     if (anno != nullptr) {
 102       ++attr_count;     // has RuntimeVisibleAnnotations attribute
 103     }
 104     if (type_anno != nullptr) {
 105       ++attr_count;     // has RuntimeVisibleTypeAnnotations attribute
 106     }
 107 
 108     write_u2(attr_count);
 109 
 110     if (initial_value_index != 0) {
 111       write_attribute_name_index("ConstantValue");
 112       write_u4(2); //length always 2
 113       write_u2(initial_value_index);
 114     }
 115     if (access_flags.is_synthetic()) {
 116       // write_synthetic_attribute();
 117     }
 118     if (generic_signature_index != 0) {
 119       write_signature_attribute(generic_signature_index);
 120     }
 121     if (anno != nullptr) {
 122       write_annotations_attribute("RuntimeVisibleAnnotations", anno);
 123     }
 124     if (type_anno != nullptr) {
 125       write_annotations_attribute("RuntimeVisibleTypeAnnotations", type_anno);
 126     }
 127   }
 128 }
 129 
 130 // Write Code attribute
 131 // JVMSpec|   Code_attribute {
 132 // JVMSpec|     u2 attribute_name_index;
 133 // JVMSpec|     u4 attribute_length;
 134 // JVMSpec|     u2 max_stack;
 135 // JVMSpec|     u2 max_locals;
 136 // JVMSpec|     u4 code_length;
 137 // JVMSpec|     u1 code[code_length];
 138 // JVMSpec|     u2 exception_table_length;
 139 // JVMSpec|     {       u2 start_pc;
 140 // JVMSpec|             u2 end_pc;
 141 // JVMSpec|             u2  handler_pc;
 142 // JVMSpec|             u2  catch_type;
 143 // JVMSpec|     }       exception_table[exception_table_length];
 144 // JVMSpec|     u2 attributes_count;
 145 // JVMSpec|     attribute_info attributes[attributes_count];
 146 // JVMSpec|   }
 147 void JvmtiClassFileReconstituter::write_code_attribute(const methodHandle& method) {
 148   ConstMethod* const_method = method->constMethod();
 149   u2 line_num_cnt = 0;
 150   int stackmap_len = 0;
 151   u2 local_variable_table_length = 0;
 152   u2 local_variable_type_table_length = 0;
 153 
 154   // compute number and length of attributes
 155   u2 attr_count = 0;
 156   int attr_size = 0;
 157   if (const_method->has_linenumber_table()) {
 158     line_num_cnt = line_number_table_entries(method);
 159     if (line_num_cnt != 0) {
 160       ++attr_count;
 161       // Compute the complete size of the line number table attribute:
 162       //      LineNumberTable_attribute {
 163       //        u2 attribute_name_index;
 164       //        u4 attribute_length;
 165       //        u2 line_number_table_length;
 166       //        {  u2 start_pc;
 167       //           u2 line_number;
 168       //        } line_number_table[line_number_table_length];
 169       //      }
 170       attr_size += 2 + 4 + 2 + line_num_cnt * (2 + 2);
 171     }
 172   }
 173   if (method->has_stackmap_table()) {
 174     stackmap_len = method->stackmap_data()->length();
 175     if (stackmap_len != 0) {
 176       ++attr_count;
 177       // Compute the  size of the stack map table attribute (VM stores raw):
 178       //      StackMapTable_attribute {
 179       //        u2 attribute_name_index;
 180       //        u4 attribute_length;
 181       //        u2 number_of_entries;
 182       //        stack_map_frame_entries[number_of_entries];
 183       //      }
 184       attr_size += 2 + 4 + stackmap_len;
 185     }
 186   }
 187   if (method->has_localvariable_table()) {
 188     local_variable_table_length = method->localvariable_table_length();
 189     if (local_variable_table_length != 0) {
 190       ++attr_count;
 191       // Compute the size of the local variable table attribute (VM stores raw):
 192       // LocalVariableTable_attribute {
 193       //   u2 attribute_name_index;
 194       //   u4 attribute_length;
 195       //   u2 local_variable_table_length;
 196       //   {
 197       //     u2 start_pc;
 198       //     u2 length;
 199       //     u2 name_index;
 200       //     u2 descriptor_index;
 201       //     u2 index;
 202       //   }
 203       attr_size += 2 + 4 + 2 + local_variable_table_length * (2 + 2 + 2 + 2 + 2);
 204 
 205       // Local variables with generic signatures must have LVTT entries
 206       LocalVariableTableElement *elem = method->localvariable_table_start();
 207       for (int idx = 0; idx < local_variable_table_length; idx++) {
 208         if (elem[idx].signature_cp_index != 0) {
 209           local_variable_type_table_length++;
 210         }
 211       }
 212 
 213       if (local_variable_type_table_length != 0) {
 214         ++attr_count;
 215         // Compute the size of the local variable type table attribute (VM stores raw):
 216         // LocalVariableTypeTable_attribute {
 217         //   u2 attribute_name_index;
 218         //   u4 attribute_length;
 219         //   u2 local_variable_type_table_length;
 220         //   {
 221         //     u2 start_pc;
 222         //     u2 length;
 223         //     u2 name_index;
 224         //     u2 signature_index;
 225         //     u2 index;
 226         //   }
 227         attr_size += 2 + 4 + 2 + local_variable_type_table_length * (2 + 2 + 2 + 2 + 2);
 228       }
 229     }
 230   }
 231 
 232   ExceptionTable exception_table(method());
 233   u2 exception_table_length = exception_table.length();
 234   int code_size = const_method->code_size();
 235   int size =
 236     2+2+4 +                                // max_stack, max_locals, code_length
 237     code_size +                            // code
 238     2 +                                    // exception_table_length
 239     (2+2+2+2) * exception_table_length +   // exception_table
 240     2 +                                    // attributes_count
 241     attr_size;                             // attributes
 242 
 243   write_attribute_name_index("Code");
 244   write_u4(size);
 245   write_u2(method->verifier_max_stack());
 246   write_u2(method->max_locals());
 247   write_u4(code_size);
 248   copy_bytecodes(method, (unsigned char*)writeable_address(code_size));
 249   write_u2(exception_table_length);
 250   for (int index = 0; index < exception_table_length; index++) {
 251     write_u2(exception_table.start_pc(index));
 252     write_u2(exception_table.end_pc(index));
 253     write_u2(exception_table.handler_pc(index));
 254     write_u2(exception_table.catch_type_index(index));
 255   }
 256   write_u2(attr_count);
 257   if (line_num_cnt != 0) {
 258     write_line_number_table_attribute(method, line_num_cnt);
 259   }
 260   if (stackmap_len != 0) {
 261     write_stackmap_table_attribute(method, stackmap_len);
 262   }
 263   if (local_variable_table_length != 0) {
 264     write_local_variable_table_attribute(method, local_variable_table_length);
 265   }
 266   if (local_variable_type_table_length != 0) {
 267     write_local_variable_type_table_attribute(method, local_variable_type_table_length);
 268   }
 269 }
 270 
 271 // Write Exceptions attribute
 272 // JVMSpec|   Exceptions_attribute {
 273 // JVMSpec|     u2 attribute_name_index;
 274 // JVMSpec|     u4 attribute_length;
 275 // JVMSpec|     u2 number_of_exceptions;
 276 // JVMSpec|     u2 exception_index_table[number_of_exceptions];
 277 // JVMSpec|   }
 278 void JvmtiClassFileReconstituter::write_exceptions_attribute(ConstMethod* const_method) {
 279   CheckedExceptionElement* checked_exceptions = const_method->checked_exceptions_start();
 280   u2 checked_exceptions_length = const_method->checked_exceptions_length();
 281   int size =
 282     2 +                                    // number_of_exceptions
 283     2 * checked_exceptions_length;         // exception_index_table
 284 
 285   write_attribute_name_index("Exceptions");
 286   write_u4(size);
 287   write_u2(checked_exceptions_length);
 288   for (int index = 0; index < checked_exceptions_length; index++) {
 289     write_u2(checked_exceptions[index].class_cp_index);
 290   }
 291 }
 292 
 293 // Write MethodParameters attribute
 294 // JVMSpec|   MethodParameters_attribute {
 295 // JVMSpec|     u2 attribute_name_index;
 296 // JVMSpec|     u4 attribute_length;
 297 // JVMSpec|     u1 parameters_count;
 298 // JVMSpec|     {   u2 name_index;
 299 // JVMSpec|         u2 access_flags;
 300 // JVMSpec|     } parameters[parameters_count];
 301 // JVMSpec|   }
 302 void JvmtiClassFileReconstituter::write_method_parameter_attribute(const ConstMethod* const_method) {
 303   const MethodParametersElement *parameters = const_method->method_parameters_start();
 304   int length = const_method->method_parameters_length();
 305   assert(length <= max_jubyte, "must fit u1");
 306   int size = 1                  // parameters_count
 307            + (2 + 2) * length;  // parameters
 308 
 309   write_attribute_name_index("MethodParameters");
 310   write_u4(size);
 311   write_u1((u1)length);
 312   for (int index = 0; index < length; index++) {
 313     write_u2(parameters[index].name_cp_index);
 314     write_u2(parameters[index].flags);
 315   }
 316 }
 317 
 318 // Write SourceFile attribute
 319 // JVMSpec|   SourceFile_attribute {
 320 // JVMSpec|     u2 attribute_name_index;
 321 // JVMSpec|     u4 attribute_length;
 322 // JVMSpec|     u2 sourcefile_index;
 323 // JVMSpec|   }
 324 void JvmtiClassFileReconstituter::write_source_file_attribute() {
 325   assert(ik()->source_file_name() != nullptr, "caller must check");
 326 
 327   write_attribute_name_index("SourceFile");
 328   write_u4(2);  // always length 2
 329   write_u2(symbol_to_cpool_index(ik()->source_file_name()));
 330 }
 331 
 332 // Write SourceDebugExtension attribute
 333 // JSR45|   SourceDebugExtension_attribute {
 334 // JSR45|       u2 attribute_name_index;
 335 // JSR45|       u4 attribute_length;
 336 // JSR45|       u1 debug_extension[attribute_length];
 337 // JSR45|   }
 338 void JvmtiClassFileReconstituter::write_source_debug_extension_attribute() {
 339   assert(ik()->source_debug_extension() != nullptr, "caller must check");
 340 
 341   write_attribute_name_index("SourceDebugExtension");
 342   int len = (int)strlen(ik()->source_debug_extension());
 343   write_u4(len);
 344   u1* ext = (u1*)ik()->source_debug_extension();
 345   for (int i=0; i<len; i++) {
 346     write_u1(ext[i]);
 347   }
 348 }
 349 
 350 // Write (generic) Signature attribute
 351 // JVMSpec|   Signature_attribute {
 352 // JVMSpec|     u2 attribute_name_index;
 353 // JVMSpec|     u4 attribute_length;
 354 // JVMSpec|     u2 signature_index;
 355 // JVMSpec|   }
 356 void JvmtiClassFileReconstituter::write_signature_attribute(u2 generic_signature_index) {
 357   write_attribute_name_index("Signature");
 358   write_u4(2);  // always length 2
 359   write_u2(generic_signature_index);
 360 }
 361 
 362 // Compute the number of entries in the InnerClasses attribute
 363 u2 JvmtiClassFileReconstituter::inner_classes_attribute_length() {
 364   InnerClassesIterator iter(ik());
 365   return checked_cast<u2>(iter.length());
 366 }
 367 
 368 // Write an annotation attribute.  The VM stores them in raw form, so all we need
 369 // to do is add the attribute name and fill in the length.
 370 // JSR202|   *Annotations_attribute {
 371 // JSR202|     u2 attribute_name_index;
 372 // JSR202|     u4 attribute_length;
 373 // JSR202|     ...
 374 // JSR202|   }
 375 void JvmtiClassFileReconstituter::write_annotations_attribute(const char* attr_name,
 376                                                               AnnotationArray* annos) {
 377   u4 length = annos->length();
 378   write_attribute_name_index(attr_name);
 379   write_u4(length);
 380   memcpy(writeable_address(length), annos->adr_at(0), length);
 381 }
 382 
 383 //  BootstrapMethods_attribute {
 384 //    u2 attribute_name_index;
 385 //    u4 attribute_length;
 386 //    u2 num_bootstrap_methods;
 387 //    {   u2 bootstrap_method_ref;
 388 //        u2 num_bootstrap_arguments;
 389 //        u2 bootstrap_arguments[num_bootstrap_arguments];
 390 //    } bootstrap_methods[num_bootstrap_methods];
 391 //  }
 392 void JvmtiClassFileReconstituter::write_bootstrapmethod_attribute() {
 393   Array<u2>* operands = cpool()->operands();
 394   write_attribute_name_index("BootstrapMethods");
 395   int num_bootstrap_methods = ConstantPool::operand_array_length(operands);
 396 
 397   // calculate length of attribute
 398   u4 length = sizeof(u2); // num_bootstrap_methods
 399   for (int n = 0; n < num_bootstrap_methods; n++) {
 400     u2 num_bootstrap_arguments = cpool()->operand_argument_count_at(n);
 401     length += sizeof(u2); // bootstrap_method_ref
 402     length += sizeof(u2); // num_bootstrap_arguments
 403     length += (u4)sizeof(u2) * num_bootstrap_arguments; // bootstrap_arguments[num_bootstrap_arguments]
 404   }
 405   write_u4(length);
 406 
 407   // write attribute
 408   write_u2(checked_cast<u2>(num_bootstrap_methods));
 409   for (int n = 0; n < num_bootstrap_methods; n++) {
 410     u2 bootstrap_method_ref = cpool()->operand_bootstrap_method_ref_index_at(n);
 411     u2 num_bootstrap_arguments = cpool()->operand_argument_count_at(n);
 412     write_u2(bootstrap_method_ref);
 413     write_u2(num_bootstrap_arguments);
 414     for (int arg = 0; arg < num_bootstrap_arguments; arg++) {
 415       u2 bootstrap_argument = cpool()->operand_argument_index_at(n, arg);
 416       write_u2(bootstrap_argument);
 417     }
 418   }
 419 }
 420 
 421 //  NestHost_attribute {
 422 //    u2 attribute_name_index;
 423 //    u4 attribute_length;
 424 //    u2 host_class_index;
 425 //  }
 426 void JvmtiClassFileReconstituter::write_nest_host_attribute() {
 427   int length = sizeof(u2);
 428   u2 host_class_index = ik()->nest_host_index();
 429 
 430   write_attribute_name_index("NestHost");
 431   write_u4(length);
 432   write_u2(host_class_index);
 433 }
 434 
 435 //  NestMembers_attribute {
 436 //    u2 attribute_name_index;
 437 //    u4 attribute_length;
 438 //    u2 number_of_classes;
 439 //    u2 classes[number_of_classes];
 440 //  }
 441 void JvmtiClassFileReconstituter::write_nest_members_attribute() {
 442   Array<u2>* nest_members = ik()->nest_members();
 443   int number_of_classes = nest_members->length();
 444   int length = sizeof(u2) * (1 + number_of_classes);
 445 
 446   write_attribute_name_index("NestMembers");
 447   write_u4(length);
 448   write_u2(checked_cast<u2>(number_of_classes));
 449   for (int i = 0; i < number_of_classes; i++) {
 450     u2 class_cp_index = nest_members->at(i);
 451     write_u2(class_cp_index);
 452   }
 453 }
 454 
 455 //  PermittedSubclasses {
 456 //    u2 attribute_name_index;
 457 //    u4 attribute_length;
 458 //    u2 number_of_classes;
 459 //    u2 classes[number_of_classes];
 460 //  }
 461 void JvmtiClassFileReconstituter::write_permitted_subclasses_attribute() {
 462   Array<u2>* permitted_subclasses = ik()->permitted_subclasses();
 463   int number_of_classes = permitted_subclasses->length();
 464   int length = sizeof(u2) * (1 + number_of_classes); // '1 +' is for number_of_classes field
 465 
 466   write_attribute_name_index("PermittedSubclasses");
 467   write_u4(length);
 468   write_u2(checked_cast<u2>(number_of_classes));
 469   for (int i = 0; i < number_of_classes; i++) {
 470     u2 class_cp_index = permitted_subclasses->at(i);
 471     write_u2(class_cp_index);
 472   }
 473 }
 474 
 475 // LoadableDescriptors {
 476 //   u2 attribute_name_index;
 477 //   u4 attribute_length;
 478 //   u2 number_of_descriptors;
 479 //   u2 descriptors[number_of_descriptors];
 480 // }
 481 void JvmtiClassFileReconstituter::write_loadable_descriptors_attribute() {
 482   Array<u2>* loadable_descriptors = ik()->loadable_descriptors();
 483   int number_of_descriptors = loadable_descriptors->length();
 484   int length = sizeof(u2) * (1 + number_of_descriptors); // '1 +' is for number_of_descriptors field
 485 
 486   write_attribute_name_index("LoadableDescriptors");
 487   write_u4(length);
 488   write_u2(checked_cast<u2>(number_of_descriptors));
 489   for (int i = 0; i < number_of_descriptors; i++) {
 490     u2 utf8_index = loadable_descriptors->at(i);
 491     write_u2(utf8_index);
 492   }
 493 }
 494 
 495 //  Record {
 496 //    u2 attribute_name_index;
 497 //    u4 attribute_length;
 498 //    u2 components_count;
 499 //    component_info components[components_count];
 500 //  }
 501 //  component_info {
 502 //    u2 name_index;
 503 //    u2 descriptor_index
 504 //    u2 attributes_count;
 505 //    attribute_info_attributes[attributes_count];
 506 //  }
 507 void JvmtiClassFileReconstituter::write_record_attribute() {
 508   Array<RecordComponent*>* components = ik()->record_components();
 509   int number_of_components = components->length();
 510 
 511   // Each component has a u2 for name, descr, attribute count
 512   u4 length = checked_cast<u4>(sizeof(u2) + (sizeof(u2) * 3 * number_of_components));
 513   for (int x = 0; x < number_of_components; x++) {
 514     RecordComponent* component = components->at(x);
 515     if (component->generic_signature_index() != 0) {
 516       length += 8; // Signature attribute size
 517     }
 518     if (component->annotations() != nullptr) {
 519       length += 6 + component->annotations()->length();
 520     }
 521     if (component->type_annotations() != nullptr) {
 522       length += 6 + component->type_annotations()->length();
 523     }
 524   }
 525 
 526   write_attribute_name_index("Record");
 527   write_u4(length);
 528   write_u2(checked_cast<u2>(number_of_components));
 529   for (int i = 0; i < number_of_components; i++) {
 530     RecordComponent* component = components->at(i);
 531     write_u2(component->name_index());
 532     write_u2(component->descriptor_index());
 533     u2 attributes_count = (component->generic_signature_index() != 0 ? 1 : 0)
 534                         + (component->annotations() != nullptr ? 1 : 0)
 535                         + (component->type_annotations() != nullptr ? 1 : 0);
 536 
 537     write_u2(attributes_count);
 538     if (component->generic_signature_index() != 0) {
 539       write_signature_attribute(component->generic_signature_index());
 540     }
 541     if (component->annotations() != nullptr) {
 542       write_annotations_attribute("RuntimeVisibleAnnotations", component->annotations());
 543     }
 544     if (component->type_annotations() != nullptr) {
 545       write_annotations_attribute("RuntimeVisibleTypeAnnotations", component->type_annotations());
 546     }
 547   }
 548 }
 549 
 550 // Write InnerClasses attribute
 551 // JVMSpec|   InnerClasses_attribute {
 552 // JVMSpec|     u2 attribute_name_index;
 553 // JVMSpec|     u4 attribute_length;
 554 // JVMSpec|     u2 number_of_classes;
 555 // JVMSpec|     {  u2 inner_class_info_index;
 556 // JVMSpec|        u2 outer_class_info_index;
 557 // JVMSpec|        u2 inner_name_index;
 558 // JVMSpec|        u2 inner_class_access_flags;
 559 // JVMSpec|     } classes[number_of_classes];
 560 // JVMSpec|   }
 561 void JvmtiClassFileReconstituter::write_inner_classes_attribute(int length) {
 562   InnerClassesIterator iter(ik());
 563   guarantee(iter.length() != 0 && iter.length() == length,
 564             "caller must check");
 565   u2 entry_count = checked_cast<u2>(length / InstanceKlass::inner_class_next_offset);
 566   u4 size = 2 + entry_count * (2+2+2+2);
 567 
 568   write_attribute_name_index("InnerClasses");
 569   write_u4(size);
 570   write_u2(entry_count);
 571   for (; !iter.done(); iter.next()) {
 572     write_u2(iter.inner_class_info_index());
 573     write_u2(iter.outer_class_info_index());
 574     write_u2(iter.inner_name_index());
 575     write_u2(iter.inner_access_flags());
 576   }
 577 }
 578 
 579 // Write Synthetic attribute
 580 // JVMSpec|   Synthetic_attribute {
 581 // JVMSpec|     u2 attribute_name_index;
 582 // JVMSpec|     u4 attribute_length;
 583 // JVMSpec|   }
 584 void JvmtiClassFileReconstituter::write_synthetic_attribute() {
 585   write_attribute_name_index("Synthetic");
 586   write_u4(0); //length always zero
 587 }
 588 
 589 // Compute size of LineNumberTable
 590 u2 JvmtiClassFileReconstituter::line_number_table_entries(const methodHandle& method) {
 591   // The line number table is compressed so we don't know how big it is until decompressed.
 592   // Decompression is really fast so we just do it twice.
 593   u2 num_entries = 0;
 594   CompressedLineNumberReadStream stream(method->compressed_linenumber_table());
 595   while (stream.read_pair()) {
 596     num_entries++;
 597   }
 598   return num_entries;
 599 }
 600 
 601 // Write LineNumberTable attribute
 602 // JVMSpec|   LineNumberTable_attribute {
 603 // JVMSpec|     u2 attribute_name_index;
 604 // JVMSpec|     u4 attribute_length;
 605 // JVMSpec|     u2 line_number_table_length;
 606 // JVMSpec|     {  u2 start_pc;
 607 // JVMSpec|        u2 line_number;
 608 // JVMSpec|     } line_number_table[line_number_table_length];
 609 // JVMSpec|   }
 610 void JvmtiClassFileReconstituter::write_line_number_table_attribute(const methodHandle& method,
 611                                                                     u2 num_entries) {
 612 
 613   write_attribute_name_index("LineNumberTable");
 614   write_u4(2 + num_entries * (2 + 2));
 615   write_u2(num_entries);
 616 
 617   CompressedLineNumberReadStream stream(method->compressed_linenumber_table());
 618   while (stream.read_pair()) {
 619     write_u2(checked_cast<u2>(stream.bci()));
 620     write_u2(checked_cast<u2>(stream.line()));
 621   }
 622 }
 623 
 624 // Write LocalVariableTable attribute
 625 // JVMSpec|   LocalVariableTable_attribute {
 626 // JVMSpec|     u2 attribute_name_index;
 627 // JVMSpec|     u4 attribute_length;
 628 // JVMSpec|     u2 local_variable_table_length;
 629 // JVMSpec|     {  u2 start_pc;
 630 // JVMSpec|       u2 length;
 631 // JVMSpec|       u2 name_index;
 632 // JVMSpec|       u2 descriptor_index;
 633 // JVMSpec|       u2 index;
 634 // JVMSpec|     } local_variable_table[local_variable_table_length];
 635 // JVMSpec|   }
 636 void JvmtiClassFileReconstituter::write_local_variable_table_attribute(const methodHandle& method, u2 num_entries) {
 637     write_attribute_name_index("LocalVariableTable");
 638     write_u4(2 + num_entries * (2 + 2 + 2 + 2 + 2));
 639     write_u2(num_entries);
 640 
 641     assert(method->localvariable_table_length() == num_entries, "just checking");
 642 
 643     LocalVariableTableElement *elem = method->localvariable_table_start();
 644     for (int j=0; j<method->localvariable_table_length(); j++) {
 645       write_u2(elem->start_bci);
 646       write_u2(elem->length);
 647       write_u2(elem->name_cp_index);
 648       write_u2(elem->descriptor_cp_index);
 649       write_u2(elem->slot);
 650       elem++;
 651     }
 652 }
 653 
 654 // Write LocalVariableTypeTable attribute
 655 // JVMSpec|   LocalVariableTypeTable_attribute {
 656 // JVMSpec|     u2 attribute_name_index;
 657 // JVMSpec|     u4 attribute_length;
 658 // JVMSpec|     u2 local_variable_type_table_length;
 659 // JVMSpec|     { u2 start_pc;
 660 // JVMSpec|       u2 length;
 661 // JVMSpec|       u2 name_index;
 662 // JVMSpec|       u2 signature_index;
 663 // JVMSpec|       u2 index;
 664 // JVMSpec|     } local_variable_type_table[local_variable_type_table_length];
 665 // JVMSpec|   }
 666 void JvmtiClassFileReconstituter::write_local_variable_type_table_attribute(const methodHandle& method, u2 num_entries) {
 667     write_attribute_name_index("LocalVariableTypeTable");
 668     write_u4(2 + num_entries * (2 + 2 + 2 + 2 + 2));
 669     write_u2(num_entries);
 670 
 671     LocalVariableTableElement *elem = method->localvariable_table_start();
 672     for (int j=0; j<method->localvariable_table_length(); j++) {
 673       if (elem->signature_cp_index > 0) {
 674         // Local variable has a generic signature - write LVTT attribute entry
 675         write_u2(elem->start_bci);
 676         write_u2(elem->length);
 677         write_u2(elem->name_cp_index);
 678         write_u2(elem->signature_cp_index);
 679         write_u2(elem->slot);
 680         num_entries--;
 681       }
 682       elem++;
 683     }
 684     assert(num_entries == 0, "just checking");
 685 }
 686 
 687 // Write stack map table attribute
 688 // JSR-202|   StackMapTable_attribute {
 689 // JSR-202|     u2 attribute_name_index;
 690 // JSR-202|     u4 attribute_length;
 691 // JSR-202|     u2 number_of_entries;
 692 // JSR-202|     stack_map_frame_entries[number_of_entries];
 693 // JSR-202|   }
 694 void JvmtiClassFileReconstituter::write_stackmap_table_attribute(const methodHandle& method,
 695                                                                  int stackmap_len) {
 696 
 697   write_attribute_name_index("StackMapTable");
 698   write_u4(stackmap_len);
 699   memcpy(
 700     writeable_address(stackmap_len),
 701     (void*)(method->stackmap_data()->adr_at(0)),
 702     stackmap_len);
 703 }
 704 
 705 // Write one method_info structure
 706 // JVMSpec|   method_info {
 707 // JVMSpec|     u2 access_flags;
 708 // JVMSpec|     u2 name_index;
 709 // JVMSpec|     u2 descriptor_index;
 710 // JVMSpec|     u2 attributes_count;
 711 // JVMSpec|     attribute_info attributes[attributes_count];
 712 // JVMSpec|   }
 713 void JvmtiClassFileReconstituter::write_method_info(const methodHandle& method) {
 714   AccessFlags access_flags = method->access_flags();
 715   ConstMethod* const_method = method->constMethod();
 716   u2 generic_signature_index = const_method->generic_signature_index();
 717   AnnotationArray* anno = method->annotations();
 718   AnnotationArray* param_anno = method->parameter_annotations();
 719   AnnotationArray* default_anno = method->annotation_default();
 720   AnnotationArray* type_anno = method->type_annotations();
 721 
 722   // skip generated default interface methods
 723   if (method->is_overpass()) {
 724     return;
 725   }
 726 
 727   write_u2(access_flags.as_method_flags());
 728   write_u2(const_method->name_index());
 729   write_u2(const_method->signature_index());
 730 
 731   // write attributes in the same order javac does, so we can test with byte for
 732   // byte comparison
 733   int attr_count = 0;
 734   if (const_method->code_size() != 0) {
 735     ++attr_count;     // has Code attribute
 736   }
 737   if (const_method->has_checked_exceptions()) {
 738     ++attr_count;     // has Exceptions attribute
 739   }
 740   if (default_anno != nullptr) {
 741     ++attr_count;     // has AnnotationDefault attribute
 742   }
 743   if (const_method->has_method_parameters()) {
 744     ++attr_count;     // has MethodParameters attribute
 745   }
 746   // Deprecated attribute would go here
 747   if (access_flags.is_synthetic()) { // FIXME
 748     // ++attr_count;
 749   }
 750   if (generic_signature_index != 0) {
 751     ++attr_count;
 752   }
 753   if (anno != nullptr) {
 754     ++attr_count;     // has RuntimeVisibleAnnotations attribute
 755   }
 756   if (param_anno != nullptr) {
 757     ++attr_count;     // has RuntimeVisibleParameterAnnotations attribute
 758   }
 759   if (type_anno != nullptr) {
 760     ++attr_count;     // has RuntimeVisibleTypeAnnotations attribute
 761   }
 762 
 763   write_u2(checked_cast<u2>(attr_count));
 764   if (const_method->code_size() > 0) {
 765     write_code_attribute(method);
 766   }
 767   if (const_method->has_checked_exceptions()) {
 768     write_exceptions_attribute(const_method);
 769   }
 770   if (default_anno != nullptr) {
 771     write_annotations_attribute("AnnotationDefault", default_anno);
 772   }
 773   if (const_method->has_method_parameters()) {
 774     write_method_parameter_attribute(const_method);
 775   }
 776   // Deprecated attribute would go here
 777   if (access_flags.is_synthetic()) {
 778     // write_synthetic_attribute();
 779   }
 780   if (generic_signature_index != 0) {
 781     write_signature_attribute(generic_signature_index);
 782   }
 783   if (anno != nullptr) {
 784     write_annotations_attribute("RuntimeVisibleAnnotations", anno);
 785   }
 786   if (param_anno != nullptr) {
 787     write_annotations_attribute("RuntimeVisibleParameterAnnotations", param_anno);
 788   }
 789   if (type_anno != nullptr) {
 790     write_annotations_attribute("RuntimeVisibleTypeAnnotations", type_anno);
 791   }
 792 }
 793 
 794 // Write the class attributes portion of ClassFile structure
 795 // JVMSpec|     u2 attributes_count;
 796 // JVMSpec|     attribute_info attributes[attributes_count];
 797 void JvmtiClassFileReconstituter::write_class_attributes() {
 798   u2 inner_classes_length = inner_classes_attribute_length();
 799   Symbol* generic_signature = ik()->generic_signature();
 800   AnnotationArray* anno = ik()->class_annotations();
 801   AnnotationArray* type_anno = ik()->class_type_annotations();
 802 
 803   u2 attr_count = 0;
 804   if (generic_signature != nullptr) {
 805     ++attr_count;
 806   }
 807   if (ik()->source_file_name() != nullptr) {
 808     ++attr_count;
 809   }
 810   if (ik()->source_debug_extension() != nullptr) {
 811     ++attr_count;
 812   }
 813   if (inner_classes_length > 0) {
 814     ++attr_count;
 815   }
 816   if (anno != nullptr) {
 817     ++attr_count;     // has RuntimeVisibleAnnotations attribute
 818   }
 819   if (type_anno != nullptr) {
 820     ++attr_count;     // has RuntimeVisibleTypeAnnotations attribute
 821   }
 822   if (cpool()->operands() != nullptr) {
 823     ++attr_count;
 824   }
 825   if (ik()->nest_host_index() != 0) {
 826     ++attr_count;
 827   }
 828   if (ik()->nest_members() != Universe::the_empty_short_array()) {
 829     ++attr_count;
 830   }
 831   if (ik()->permitted_subclasses() != Universe::the_empty_short_array()) {
 832     ++attr_count;
 833   }
 834   if (ik()->loadable_descriptors() != Universe::the_empty_short_array()) {
 835     ++attr_count;
 836   }
 837   if (ik()->record_components() != nullptr) {
 838     ++attr_count;
 839   }
 840 
 841   write_u2(attr_count);
 842 
 843   if (generic_signature != nullptr) {
 844     write_signature_attribute(symbol_to_cpool_index(generic_signature));
 845   }
 846   if (ik()->source_file_name() != nullptr) {
 847     write_source_file_attribute();
 848   }
 849   if (ik()->source_debug_extension() != nullptr) {
 850     write_source_debug_extension_attribute();
 851   }
 852   if (anno != nullptr) {
 853     write_annotations_attribute("RuntimeVisibleAnnotations", anno);
 854   }
 855   if (type_anno != nullptr) {
 856     write_annotations_attribute("RuntimeVisibleTypeAnnotations", type_anno);
 857   }
 858   if (ik()->nest_host_index() != 0) {
 859     write_nest_host_attribute();
 860   }
 861   if (ik()->nest_members() != Universe::the_empty_short_array()) {
 862     write_nest_members_attribute();
 863   }
 864   if (ik()->permitted_subclasses() != Universe::the_empty_short_array()) {
 865     write_permitted_subclasses_attribute();
 866   }
 867   if (ik()->loadable_descriptors() != Universe::the_empty_short_array()) {
 868     write_loadable_descriptors_attribute();
 869   }
 870   if (ik()->record_components() != nullptr) {
 871     write_record_attribute();
 872   }
 873   if (cpool()->operands() != nullptr) {
 874     write_bootstrapmethod_attribute();
 875   }
 876   if (inner_classes_length > 0) {
 877     write_inner_classes_attribute(inner_classes_length);
 878   }
 879 }
 880 
 881 // Write the method information portion of ClassFile structure
 882 // JVMSpec|     u2 methods_count;
 883 // JVMSpec|     method_info methods[methods_count];
 884 void JvmtiClassFileReconstituter::write_method_infos() {
 885   HandleMark hm(thread());
 886   Array<Method*>* methods = ik()->methods();
 887   int num_methods = methods->length();
 888   int num_overpass = 0;
 889 
 890   // count the generated default interface methods
 891   // these will not be re-created by write_method_info
 892   // and should not be included in the total count
 893   for (int index = 0; index < num_methods; index++) {
 894     Method* method = methods->at(index);
 895     if (method->is_overpass()) {
 896       num_overpass++;
 897     }
 898   }
 899 
 900   write_u2(checked_cast<u2>(num_methods - num_overpass));
 901   if (JvmtiExport::can_maintain_original_method_order()) {
 902     int index;
 903     int original_index;
 904     intArray method_order(num_methods, num_methods, 0);
 905 
 906     // invert the method order mapping
 907     for (index = 0; index < num_methods; index++) {
 908       original_index = ik()->method_ordering()->at(index);
 909       assert(original_index >= 0 && original_index < num_methods,
 910              "invalid original method index");
 911       method_order.at_put(original_index, index);
 912     }
 913 
 914     // write in original order
 915     for (original_index = 0; original_index < num_methods; original_index++) {
 916       index = method_order.at(original_index);
 917       methodHandle method(thread(), methods->at(index));
 918       write_method_info(method);
 919     }
 920   } else {
 921     // method order not preserved just dump the method infos
 922     for (int index = 0; index < num_methods; index++) {
 923       methodHandle method(thread(), methods->at(index));
 924       write_method_info(method);
 925     }
 926   }
 927 }
 928 
 929 void JvmtiClassFileReconstituter::write_class_file_format() {
 930   ReallocMark();
 931 
 932   // JVMSpec|   ClassFile {
 933   // JVMSpec|           u4 magic;
 934   write_u4(0xCAFEBABE);
 935 
 936   // JVMSpec|           u2 minor_version;
 937   // JVMSpec|           u2 major_version;
 938   write_u2(ik()->minor_version());
 939   u2 major = ik()->major_version();
 940   write_u2(major);
 941 
 942   // JVMSpec|           u2 constant_pool_count;
 943   // JVMSpec|           cp_info constant_pool[constant_pool_count-1];
 944   write_u2(checked_cast<u2>(cpool()->length()));
 945   copy_cpool_bytes(writeable_address(cpool_size()));
 946 
 947   // JVMSpec|           u2 access_flags;
 948   write_u2(ik()->access_flags().as_class_flags());
 949 
 950   // JVMSpec|           u2 this_class;
 951   // JVMSpec|           u2 super_class;
 952   write_u2(class_symbol_to_cpool_index(ik()->name()));
 953   Klass* super_class = ik()->super();
 954   write_u2(super_class == nullptr? 0 :  // zero for java.lang.Object
 955                 class_symbol_to_cpool_index(super_class->name()));
 956 
 957   // JVMSpec|           u2 interfaces_count;
 958   // JVMSpec|           u2 interfaces[interfaces_count];
 959   Array<InstanceKlass*>* interfaces =  ik()->local_interfaces();
 960   int num_interfaces = interfaces->length();
 961   write_u2(checked_cast<u2>(num_interfaces));
 962   for (int index = 0; index < num_interfaces; index++) {
 963     HandleMark hm(thread());
 964     InstanceKlass* iik = interfaces->at(index);
 965     write_u2(class_symbol_to_cpool_index(iik->name()));
 966   }
 967 
 968   // JVMSpec|           u2 fields_count;
 969   // JVMSpec|           field_info fields[fields_count];
 970   write_field_infos();
 971 
 972   // JVMSpec|           u2 methods_count;
 973   // JVMSpec|           method_info methods[methods_count];
 974   write_method_infos();
 975 
 976   // JVMSpec|           u2 attributes_count;
 977   // JVMSpec|           attribute_info attributes[attributes_count];
 978   // JVMSpec|   } /* end ClassFile 8?
 979   write_class_attributes();
 980 }
 981 
 982 address JvmtiClassFileReconstituter::writeable_address(size_t size) {
 983   size_t used_size = _buffer_ptr - _buffer;
 984   if (size + used_size >= _buffer_size) {
 985     // compute the new buffer size: must be at least twice as big as before
 986     // plus whatever new is being used; then convert to nice clean block boundary
 987     size_t new_buffer_size = (size + _buffer_size*2 + 1) / initial_buffer_size
 988                                                          * initial_buffer_size;
 989 
 990     // VM goes belly-up if the memory isn't available, so cannot do OOM processing
 991     _buffer = REALLOC_RESOURCE_ARRAY(u1, _buffer, _buffer_size, new_buffer_size);
 992     _buffer_size = new_buffer_size;
 993     _buffer_ptr = _buffer + used_size;
 994   }
 995   u1* ret_ptr = _buffer_ptr;
 996   _buffer_ptr += size;
 997   return ret_ptr;
 998 }
 999 
1000 void JvmtiClassFileReconstituter::write_attribute_name_index(const char* name) {
1001   TempNewSymbol sym = SymbolTable::probe(name, (int)strlen(name));
1002   assert(sym != nullptr, "attribute name symbol not found");
1003   u2 attr_name_index = symbol_to_cpool_index(sym);
1004   assert(attr_name_index != 0, "attribute name symbol not in constant pool");
1005   write_u2(attr_name_index);
1006 }
1007 
1008 void JvmtiClassFileReconstituter::write_u1(u1 x) {
1009   *writeable_address(1) = x;
1010 }
1011 
1012 void JvmtiClassFileReconstituter::write_u2(u2 x) {
1013   Bytes::put_Java_u2(writeable_address(2), x);
1014 }
1015 
1016 void JvmtiClassFileReconstituter::write_u4(u4 x) {
1017   Bytes::put_Java_u4(writeable_address(4), x);
1018 }
1019 
1020 void JvmtiClassFileReconstituter::write_u8(u8 x) {
1021   Bytes::put_Java_u8(writeable_address(8), x);
1022 }
1023 
1024 void JvmtiClassFileReconstituter::copy_bytecodes(const methodHandle& mh,
1025                                                  unsigned char* bytecodes) {
1026   // use a BytecodeStream to iterate over the bytecodes. JVM/fast bytecodes
1027   // and the breakpoint bytecode are converted to their original bytecodes.
1028 
1029   BytecodeStream bs(mh);
1030 
1031   unsigned char* p = bytecodes;
1032   Bytecodes::Code code;
1033   bool is_rewritten = mh->method_holder()->is_rewritten();
1034 
1035   while ((code = bs.next()) >= 0) {
1036     assert(Bytecodes::is_java_code(code), "sanity check");
1037     assert(code != Bytecodes::_breakpoint, "sanity check");
1038 
1039     // length of bytecode (mnemonic + operands)
1040     address bcp = bs.bcp();
1041     int     len = bs.instruction_size();
1042     assert(len > 0, "length must be > 0");
1043 
1044     // copy the bytecodes
1045     *p = (unsigned char) (bs.is_wide()? Bytecodes::_wide : code);
1046     if (len > 1) {
1047       memcpy(p+1, bcp+1, len-1);
1048     }
1049 
1050     // During linking the get/put and invoke instructions are rewritten
1051     // with an index into the constant pool cache. The original constant
1052     // pool index must be returned to caller.  Rewrite the index.
1053     if (is_rewritten && len > 1) {
1054       bool is_wide = false;
1055       switch (code) {
1056       case Bytecodes::_getstatic       :  // fall through
1057       case Bytecodes::_putstatic       :  // fall through
1058       case Bytecodes::_getfield        :  // fall through
1059       case Bytecodes::_putfield        : {
1060         int field_index = Bytes::get_native_u2(bcp+1);
1061         u2 pool_index = mh->constants()->resolved_field_entry_at(field_index)->constant_pool_index();
1062         assert(pool_index < mh->constants()->length(), "sanity check");
1063         Bytes::put_Java_u2((address)(p+1), pool_index);     // java byte ordering
1064         break;
1065       }
1066       case Bytecodes::_invokevirtual   :  // fall through
1067       case Bytecodes::_invokespecial   :  // fall through
1068       case Bytecodes::_invokestatic    :  // fall through
1069       case Bytecodes::_invokedynamic   :  // fall through
1070       case Bytecodes::_invokeinterface : {
1071         assert(len == 3 ||
1072                (code == Bytecodes::_invokeinterface && len == 5) ||
1073                (code == Bytecodes::_invokedynamic   && len == 5),
1074                "sanity check");
1075 
1076         int cpci = Bytes::get_native_u2(bcp+1);
1077         bool is_invokedynamic = (code == Bytecodes::_invokedynamic);
1078         int pool_index;
1079         if (is_invokedynamic) {
1080           cpci = Bytes::get_native_u4(bcp+1);
1081           pool_index = mh->constants()->resolved_indy_entry_at(cpci)->constant_pool_index();
1082         } else {
1083           // cache cannot be pre-fetched since some classes won't have it yet
1084           pool_index = mh->constants()->resolved_method_entry_at(cpci)->constant_pool_index();
1085         }
1086         assert(pool_index < mh->constants()->length(), "sanity check");
1087         Bytes::put_Java_u2((address)(p+1), (u2)pool_index);     // java byte ordering
1088         if (is_invokedynamic)  *(p+3) = *(p+4) = 0;
1089         break;
1090       }
1091       case Bytecodes::_ldc_w:
1092         is_wide = true; // fall through
1093       case Bytecodes::_ldc: {
1094         if (bs.raw_code() == Bytecodes::_fast_aldc || bs.raw_code() == Bytecodes::_fast_aldc_w) {
1095           int cpci = is_wide ? Bytes::get_native_u2(bcp+1) : (u1)(*(bcp+1));
1096           int i = mh->constants()->object_to_cp_index(cpci);
1097           assert(i < mh->constants()->length(), "sanity check");
1098           if (is_wide) {
1099             Bytes::put_Java_u2((address)(p+1), (u2)i);     // java byte ordering
1100           } else {
1101             *(p+1) = (u1)i;
1102           }
1103         }
1104         break;
1105         }
1106       default:
1107         break;
1108       }
1109     }
1110 
1111     p += len;
1112   }
1113 }