1 /*
   2  * Copyright (c) 2005, 2023, 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 "precompiled.hpp"
  26 #include "classfile/symbolTable.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.get_flags() & JVM_RECOGNIZED_FIELD_MODIFIERS);
  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", "RuntimeInvisibleAnnotations", anno);
 123     }
 124     if (type_anno != nullptr) {
 125       write_annotations_attribute("RuntimeVisibleTypeAnnotations", "RuntimeInvisibleTypeAnnotations", 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 void JvmtiClassFileReconstituter::write_annotations_attribute(const char* attr_name,
 384                                                               const char* fallback_attr_name,
 385                                                               AnnotationArray* annos) {
 386   TempNewSymbol sym = SymbolTable::probe(attr_name, (int)strlen(attr_name));
 387   if (sym != nullptr) {
 388     if (symbol_to_cpool_index(sym) != 0) {
 389       write_annotations_attribute(attr_name, annos);
 390       return;
 391     }
 392   }
 393   // use fallback name
 394   write_annotations_attribute(fallback_attr_name, annos);
 395 }
 396 
 397 //  BootstrapMethods_attribute {
 398 //    u2 attribute_name_index;
 399 //    u4 attribute_length;
 400 //    u2 num_bootstrap_methods;
 401 //    {   u2 bootstrap_method_ref;
 402 //        u2 num_bootstrap_arguments;
 403 //        u2 bootstrap_arguments[num_bootstrap_arguments];
 404 //    } bootstrap_methods[num_bootstrap_methods];
 405 //  }
 406 void JvmtiClassFileReconstituter::write_bootstrapmethod_attribute() {
 407   Array<u2>* operands = cpool()->operands();
 408   write_attribute_name_index("BootstrapMethods");
 409   int num_bootstrap_methods = ConstantPool::operand_array_length(operands);
 410 
 411   // calculate length of attribute
 412   u4 length = sizeof(u2); // num_bootstrap_methods
 413   for (int n = 0; n < num_bootstrap_methods; n++) {
 414     u2 num_bootstrap_arguments = cpool()->operand_argument_count_at(n);
 415     length += sizeof(u2); // bootstrap_method_ref
 416     length += sizeof(u2); // num_bootstrap_arguments
 417     length += (u4)sizeof(u2) * num_bootstrap_arguments; // bootstrap_arguments[num_bootstrap_arguments]
 418   }
 419   write_u4(length);
 420 
 421   // write attribute
 422   write_u2(checked_cast<u2>(num_bootstrap_methods));
 423   for (int n = 0; n < num_bootstrap_methods; n++) {
 424     u2 bootstrap_method_ref = cpool()->operand_bootstrap_method_ref_index_at(n);
 425     u2 num_bootstrap_arguments = cpool()->operand_argument_count_at(n);
 426     write_u2(bootstrap_method_ref);
 427     write_u2(num_bootstrap_arguments);
 428     for (int arg = 0; arg < num_bootstrap_arguments; arg++) {
 429       u2 bootstrap_argument = cpool()->operand_argument_index_at(n, arg);
 430       write_u2(bootstrap_argument);
 431     }
 432   }
 433 }
 434 
 435 //  NestHost_attribute {
 436 //    u2 attribute_name_index;
 437 //    u4 attribute_length;
 438 //    u2 host_class_index;
 439 //  }
 440 void JvmtiClassFileReconstituter::write_nest_host_attribute() {
 441   int length = sizeof(u2);
 442   u2 host_class_index = ik()->nest_host_index();
 443 
 444   write_attribute_name_index("NestHost");
 445   write_u4(length);
 446   write_u2(host_class_index);
 447 }
 448 
 449 //  NestMembers_attribute {
 450 //    u2 attribute_name_index;
 451 //    u4 attribute_length;
 452 //    u2 number_of_classes;
 453 //    u2 classes[number_of_classes];
 454 //  }
 455 void JvmtiClassFileReconstituter::write_nest_members_attribute() {
 456   Array<u2>* nest_members = ik()->nest_members();
 457   int number_of_classes = nest_members->length();
 458   int length = sizeof(u2) * (1 + number_of_classes);
 459 
 460   write_attribute_name_index("NestMembers");
 461   write_u4(length);
 462   write_u2(checked_cast<u2>(number_of_classes));
 463   for (int i = 0; i < number_of_classes; i++) {
 464     u2 class_cp_index = nest_members->at(i);
 465     write_u2(class_cp_index);
 466   }
 467 }
 468 
 469 //  PermittedSubclasses {
 470 //    u2 attribute_name_index;
 471 //    u4 attribute_length;
 472 //    u2 number_of_classes;
 473 //    u2 classes[number_of_classes];
 474 //  }
 475 void JvmtiClassFileReconstituter::write_permitted_subclasses_attribute() {
 476   Array<u2>* permitted_subclasses = ik()->permitted_subclasses();
 477   int number_of_classes = permitted_subclasses->length();
 478   int length = sizeof(u2) * (1 + number_of_classes); // '1 +' is for number_of_classes field
 479 
 480   write_attribute_name_index("PermittedSubclasses");
 481   write_u4(length);
 482   write_u2(checked_cast<u2>(number_of_classes));
 483   for (int i = 0; i < number_of_classes; i++) {
 484     u2 class_cp_index = permitted_subclasses->at(i);
 485     write_u2(class_cp_index);
 486   }
 487 }
 488 
 489 //  Record {
 490 //    u2 attribute_name_index;
 491 //    u4 attribute_length;
 492 //    u2 components_count;
 493 //    component_info components[components_count];
 494 //  }
 495 //  component_info {
 496 //    u2 name_index;
 497 //    u2 descriptor_index
 498 //    u2 attributes_count;
 499 //    attribute_info_attributes[attributes_count];
 500 //  }
 501 void JvmtiClassFileReconstituter::write_record_attribute() {
 502   Array<RecordComponent*>* components = ik()->record_components();
 503   int number_of_components = components->length();
 504 
 505   // Each component has a u2 for name, descr, attribute count
 506   u4 length = checked_cast<u4>(sizeof(u2) + (sizeof(u2) * 3 * number_of_components));
 507   for (int x = 0; x < number_of_components; x++) {
 508     RecordComponent* component = components->at(x);
 509     if (component->generic_signature_index() != 0) {
 510       length += 8; // Signature attribute size
 511     }
 512     if (component->annotations() != nullptr) {
 513       length += 6 + component->annotations()->length();
 514     }
 515     if (component->type_annotations() != nullptr) {
 516       length += 6 + component->type_annotations()->length();
 517     }
 518   }
 519 
 520   write_attribute_name_index("Record");
 521   write_u4(length);
 522   write_u2(checked_cast<u2>(number_of_components));
 523   for (int i = 0; i < number_of_components; i++) {
 524     RecordComponent* component = components->at(i);
 525     write_u2(component->name_index());
 526     write_u2(component->descriptor_index());
 527     u2 attributes_count = (component->generic_signature_index() != 0 ? 1 : 0)
 528                         + (component->annotations() != nullptr ? 1 : 0)
 529                         + (component->type_annotations() != nullptr ? 1 : 0);
 530 
 531     write_u2(attributes_count);
 532     if (component->generic_signature_index() != 0) {
 533       write_signature_attribute(component->generic_signature_index());
 534     }
 535     if (component->annotations() != nullptr) {
 536       write_annotations_attribute("RuntimeVisibleAnnotations", "RuntimeInvisibleAnnotations", component->annotations());
 537     }
 538     if (component->type_annotations() != nullptr) {
 539       write_annotations_attribute("RuntimeVisibleTypeAnnotations", "RuntimeInvisibleTypeAnnotations", component->type_annotations());
 540     }
 541   }
 542 }
 543 
 544 // Write InnerClasses attribute
 545 // JVMSpec|   InnerClasses_attribute {
 546 // JVMSpec|     u2 attribute_name_index;
 547 // JVMSpec|     u4 attribute_length;
 548 // JVMSpec|     u2 number_of_classes;
 549 // JVMSpec|     {  u2 inner_class_info_index;
 550 // JVMSpec|        u2 outer_class_info_index;
 551 // JVMSpec|        u2 inner_name_index;
 552 // JVMSpec|        u2 inner_class_access_flags;
 553 // JVMSpec|     } classes[number_of_classes];
 554 // JVMSpec|   }
 555 void JvmtiClassFileReconstituter::write_inner_classes_attribute(int length) {
 556   InnerClassesIterator iter(ik());
 557   guarantee(iter.length() != 0 && iter.length() == length,
 558             "caller must check");
 559   u2 entry_count = checked_cast<u2>(length / InstanceKlass::inner_class_next_offset);
 560   u4 size = 2 + entry_count * (2+2+2+2);
 561 
 562   write_attribute_name_index("InnerClasses");
 563   write_u4(size);
 564   write_u2(entry_count);
 565   for (; !iter.done(); iter.next()) {
 566     write_u2(iter.inner_class_info_index());
 567     write_u2(iter.outer_class_info_index());
 568     write_u2(iter.inner_name_index());
 569     write_u2(iter.inner_access_flags());
 570   }
 571 }
 572 
 573 // Write Synthetic attribute
 574 // JVMSpec|   Synthetic_attribute {
 575 // JVMSpec|     u2 attribute_name_index;
 576 // JVMSpec|     u4 attribute_length;
 577 // JVMSpec|   }
 578 void JvmtiClassFileReconstituter::write_synthetic_attribute() {
 579   write_attribute_name_index("Synthetic");
 580   write_u4(0); //length always zero
 581 }
 582 
 583 // Compute size of LineNumberTable
 584 u2 JvmtiClassFileReconstituter::line_number_table_entries(const methodHandle& method) {
 585   // The line number table is compressed so we don't know how big it is until decompressed.
 586   // Decompression is really fast so we just do it twice.
 587   u2 num_entries = 0;
 588   CompressedLineNumberReadStream stream(method->compressed_linenumber_table());
 589   while (stream.read_pair()) {
 590     num_entries++;
 591   }
 592   return num_entries;
 593 }
 594 
 595 // Write LineNumberTable attribute
 596 // JVMSpec|   LineNumberTable_attribute {
 597 // JVMSpec|     u2 attribute_name_index;
 598 // JVMSpec|     u4 attribute_length;
 599 // JVMSpec|     u2 line_number_table_length;
 600 // JVMSpec|     {  u2 start_pc;
 601 // JVMSpec|        u2 line_number;
 602 // JVMSpec|     } line_number_table[line_number_table_length];
 603 // JVMSpec|   }
 604 void JvmtiClassFileReconstituter::write_line_number_table_attribute(const methodHandle& method,
 605                                                                     u2 num_entries) {
 606 
 607   write_attribute_name_index("LineNumberTable");
 608   write_u4(2 + num_entries * (2 + 2));
 609   write_u2(num_entries);
 610 
 611   CompressedLineNumberReadStream stream(method->compressed_linenumber_table());
 612   while (stream.read_pair()) {
 613     write_u2(checked_cast<u2>(stream.bci()));
 614     write_u2(checked_cast<u2>(stream.line()));
 615   }
 616 }
 617 
 618 // Write LocalVariableTable attribute
 619 // JVMSpec|   LocalVariableTable_attribute {
 620 // JVMSpec|     u2 attribute_name_index;
 621 // JVMSpec|     u4 attribute_length;
 622 // JVMSpec|     u2 local_variable_table_length;
 623 // JVMSpec|     {  u2 start_pc;
 624 // JVMSpec|       u2 length;
 625 // JVMSpec|       u2 name_index;
 626 // JVMSpec|       u2 descriptor_index;
 627 // JVMSpec|       u2 index;
 628 // JVMSpec|     } local_variable_table[local_variable_table_length];
 629 // JVMSpec|   }
 630 void JvmtiClassFileReconstituter::write_local_variable_table_attribute(const methodHandle& method, u2 num_entries) {
 631     write_attribute_name_index("LocalVariableTable");
 632     write_u4(2 + num_entries * (2 + 2 + 2 + 2 + 2));
 633     write_u2(num_entries);
 634 
 635     assert(method->localvariable_table_length() == num_entries, "just checking");
 636 
 637     LocalVariableTableElement *elem = method->localvariable_table_start();
 638     for (int j=0; j<method->localvariable_table_length(); j++) {
 639       write_u2(elem->start_bci);
 640       write_u2(elem->length);
 641       write_u2(elem->name_cp_index);
 642       write_u2(elem->descriptor_cp_index);
 643       write_u2(elem->slot);
 644       elem++;
 645     }
 646 }
 647 
 648 // Write LocalVariableTypeTable attribute
 649 // JVMSpec|   LocalVariableTypeTable_attribute {
 650 // JVMSpec|     u2 attribute_name_index;
 651 // JVMSpec|     u4 attribute_length;
 652 // JVMSpec|     u2 local_variable_type_table_length;
 653 // JVMSpec|     { u2 start_pc;
 654 // JVMSpec|       u2 length;
 655 // JVMSpec|       u2 name_index;
 656 // JVMSpec|       u2 signature_index;
 657 // JVMSpec|       u2 index;
 658 // JVMSpec|     } local_variable_type_table[local_variable_type_table_length];
 659 // JVMSpec|   }
 660 void JvmtiClassFileReconstituter::write_local_variable_type_table_attribute(const methodHandle& method, u2 num_entries) {
 661     write_attribute_name_index("LocalVariableTypeTable");
 662     write_u4(2 + num_entries * (2 + 2 + 2 + 2 + 2));
 663     write_u2(num_entries);
 664 
 665     LocalVariableTableElement *elem = method->localvariable_table_start();
 666     for (int j=0; j<method->localvariable_table_length(); j++) {
 667       if (elem->signature_cp_index > 0) {
 668         // Local variable has a generic signature - write LVTT attribute entry
 669         write_u2(elem->start_bci);
 670         write_u2(elem->length);
 671         write_u2(elem->name_cp_index);
 672         write_u2(elem->signature_cp_index);
 673         write_u2(elem->slot);
 674         num_entries--;
 675       }
 676       elem++;
 677     }
 678     assert(num_entries == 0, "just checking");
 679 }
 680 
 681 // Write stack map table attribute
 682 // JSR-202|   StackMapTable_attribute {
 683 // JSR-202|     u2 attribute_name_index;
 684 // JSR-202|     u4 attribute_length;
 685 // JSR-202|     u2 number_of_entries;
 686 // JSR-202|     stack_map_frame_entries[number_of_entries];
 687 // JSR-202|   }
 688 void JvmtiClassFileReconstituter::write_stackmap_table_attribute(const methodHandle& method,
 689                                                                  int stackmap_len) {
 690 
 691   write_attribute_name_index("StackMapTable");
 692   write_u4(stackmap_len);
 693   memcpy(
 694     writeable_address(stackmap_len),
 695     (void*)(method->stackmap_data()->adr_at(0)),
 696     stackmap_len);
 697 }
 698 
 699 // Write one method_info structure
 700 // JVMSpec|   method_info {
 701 // JVMSpec|     u2 access_flags;
 702 // JVMSpec|     u2 name_index;
 703 // JVMSpec|     u2 descriptor_index;
 704 // JVMSpec|     u2 attributes_count;
 705 // JVMSpec|     attribute_info attributes[attributes_count];
 706 // JVMSpec|   }
 707 void JvmtiClassFileReconstituter::write_method_info(const methodHandle& method) {
 708   AccessFlags access_flags = method->access_flags();
 709   ConstMethod* const_method = method->constMethod();
 710   u2 generic_signature_index = const_method->generic_signature_index();
 711   AnnotationArray* anno = method->annotations();
 712   AnnotationArray* param_anno = method->parameter_annotations();
 713   AnnotationArray* default_anno = method->annotation_default();
 714   AnnotationArray* type_anno = method->type_annotations();
 715 
 716   // skip generated default interface methods
 717   if (method->is_overpass()) {
 718     return;
 719   }
 720 
 721   write_u2(access_flags.get_flags() & JVM_RECOGNIZED_METHOD_MODIFIERS);
 722   write_u2(const_method->name_index());
 723   write_u2(const_method->signature_index());
 724 
 725   // write attributes in the same order javac does, so we can test with byte for
 726   // byte comparison
 727   int attr_count = 0;
 728   if (const_method->code_size() != 0) {
 729     ++attr_count;     // has Code attribute
 730   }
 731   if (const_method->has_checked_exceptions()) {
 732     ++attr_count;     // has Exceptions attribute
 733   }
 734   if (default_anno != nullptr) {
 735     ++attr_count;     // has AnnotationDefault attribute
 736   }
 737   if (const_method->has_method_parameters()) {
 738     ++attr_count;     // has MethodParameters attribute
 739   }
 740   // Deprecated attribute would go here
 741   if (access_flags.is_synthetic()) { // FIXME
 742     // ++attr_count;
 743   }
 744   if (generic_signature_index != 0) {
 745     ++attr_count;
 746   }
 747   if (anno != nullptr) {
 748     ++attr_count;     // has RuntimeVisibleAnnotations attribute
 749   }
 750   if (param_anno != nullptr) {
 751     ++attr_count;     // has RuntimeVisibleParameterAnnotations attribute
 752   }
 753   if (type_anno != nullptr) {
 754     ++attr_count;     // has RuntimeVisibleTypeAnnotations attribute
 755   }
 756 
 757   write_u2(checked_cast<u2>(attr_count));
 758   if (const_method->code_size() > 0) {
 759     write_code_attribute(method);
 760   }
 761   if (const_method->has_checked_exceptions()) {
 762     write_exceptions_attribute(const_method);
 763   }
 764   if (default_anno != nullptr) {
 765     write_annotations_attribute("AnnotationDefault", default_anno);
 766   }
 767   if (const_method->has_method_parameters()) {
 768     write_method_parameter_attribute(const_method);
 769   }
 770   // Deprecated attribute would go here
 771   if (access_flags.is_synthetic()) {
 772     // write_synthetic_attribute();
 773   }
 774   if (generic_signature_index != 0) {
 775     write_signature_attribute(generic_signature_index);
 776   }
 777   if (anno != nullptr) {
 778     write_annotations_attribute("RuntimeVisibleAnnotations", "RuntimeInvisibleAnnotations", anno);
 779   }
 780   if (param_anno != nullptr) {
 781     write_annotations_attribute("RuntimeVisibleParameterAnnotations", "RuntimeInvisibleParameterAnnotations", param_anno);
 782   }
 783   if (type_anno != nullptr) {
 784     write_annotations_attribute("RuntimeVisibleTypeAnnotations", "RuntimeInvisibleTypeAnnotations", type_anno);
 785   }
 786 }
 787 
 788 // Write the class attributes portion of ClassFile structure
 789 // JVMSpec|     u2 attributes_count;
 790 // JVMSpec|     attribute_info attributes[attributes_count];
 791 void JvmtiClassFileReconstituter::write_class_attributes() {
 792   u2 inner_classes_length = inner_classes_attribute_length();
 793   Symbol* generic_signature = ik()->generic_signature();
 794   AnnotationArray* anno = ik()->class_annotations();
 795   AnnotationArray* type_anno = ik()->class_type_annotations();
 796 
 797   u2 attr_count = 0;
 798   if (generic_signature != nullptr) {
 799     ++attr_count;
 800   }
 801   if (ik()->source_file_name() != nullptr) {
 802     ++attr_count;
 803   }
 804   if (ik()->source_debug_extension() != nullptr) {
 805     ++attr_count;
 806   }
 807   if (inner_classes_length > 0) {
 808     ++attr_count;
 809   }
 810   if (anno != nullptr) {
 811     ++attr_count;     // has RuntimeVisibleAnnotations attribute
 812   }
 813   if (type_anno != nullptr) {
 814     ++attr_count;     // has RuntimeVisibleTypeAnnotations attribute
 815   }
 816   if (cpool()->operands() != nullptr) {
 817     ++attr_count;
 818   }
 819   if (ik()->nest_host_index() != 0) {
 820     ++attr_count;
 821   }
 822   if (ik()->nest_members() != Universe::the_empty_short_array()) {
 823     ++attr_count;
 824   }
 825   if (ik()->permitted_subclasses() != Universe::the_empty_short_array()) {
 826     ++attr_count;
 827   }
 828   if (ik()->record_components() != nullptr) {
 829     ++attr_count;
 830   }
 831 
 832   write_u2(attr_count);
 833 
 834   if (generic_signature != nullptr) {
 835     write_signature_attribute(symbol_to_cpool_index(generic_signature));
 836   }
 837   if (ik()->source_file_name() != nullptr) {
 838     write_source_file_attribute();
 839   }
 840   if (ik()->source_debug_extension() != nullptr) {
 841     write_source_debug_extension_attribute();
 842   }
 843   if (anno != nullptr) {
 844     write_annotations_attribute("RuntimeVisibleAnnotations", "RuntimeInvisibleAnnotations", anno);
 845   }
 846   if (type_anno != nullptr) {
 847     write_annotations_attribute("RuntimeVisibleTypeAnnotations", "RuntimeInvisibleTypeAnnotations", type_anno);
 848   }
 849   if (ik()->nest_host_index() != 0) {
 850     write_nest_host_attribute();
 851   }
 852   if (ik()->nest_members() != Universe::the_empty_short_array()) {
 853     write_nest_members_attribute();
 854   }
 855   if (ik()->permitted_subclasses() != Universe::the_empty_short_array()) {
 856     write_permitted_subclasses_attribute();
 857   }
 858   if (ik()->record_components() != nullptr) {
 859     write_record_attribute();
 860   }
 861   if (cpool()->operands() != nullptr) {
 862     write_bootstrapmethod_attribute();
 863   }
 864   if (inner_classes_length > 0) {
 865     write_inner_classes_attribute(inner_classes_length);
 866   }
 867 }
 868 
 869 // Write the method information portion of ClassFile structure
 870 // JVMSpec|     u2 methods_count;
 871 // JVMSpec|     method_info methods[methods_count];
 872 void JvmtiClassFileReconstituter::write_method_infos() {
 873   HandleMark hm(thread());
 874   Array<Method*>* methods = ik()->methods();
 875   int num_methods = methods->length();
 876   int num_overpass = 0;
 877 
 878   // count the generated default interface methods
 879   // these will not be re-created by write_method_info
 880   // and should not be included in the total count
 881   for (int index = 0; index < num_methods; index++) {
 882     Method* method = methods->at(index);
 883     if (method->is_overpass()) {
 884       num_overpass++;
 885     }
 886   }
 887 
 888   write_u2(checked_cast<u2>(num_methods - num_overpass));
 889   if (JvmtiExport::can_maintain_original_method_order()) {
 890     int index;
 891     int original_index;
 892     intArray method_order(num_methods, num_methods, 0);
 893 
 894     // invert the method order mapping
 895     for (index = 0; index < num_methods; index++) {
 896       original_index = ik()->method_ordering()->at(index);
 897       assert(original_index >= 0 && original_index < num_methods,
 898              "invalid original method index");
 899       method_order.at_put(original_index, index);
 900     }
 901 
 902     // write in original order
 903     for (original_index = 0; original_index < num_methods; original_index++) {
 904       index = method_order.at(original_index);
 905       methodHandle method(thread(), methods->at(index));
 906       write_method_info(method);
 907     }
 908   } else {
 909     // method order not preserved just dump the method infos
 910     for (int index = 0; index < num_methods; index++) {
 911       methodHandle method(thread(), methods->at(index));
 912       write_method_info(method);
 913     }
 914   }
 915 }
 916 
 917 void JvmtiClassFileReconstituter::write_class_file_format() {
 918   ReallocMark();
 919 
 920   // JVMSpec|   ClassFile {
 921   // JVMSpec|           u4 magic;
 922   write_u4(0xCAFEBABE);
 923 
 924   // JVMSpec|           u2 minor_version;
 925   // JVMSpec|           u2 major_version;
 926   write_u2(ik()->minor_version());
 927   u2 major = ik()->major_version();
 928   write_u2(major);
 929 
 930   // JVMSpec|           u2 constant_pool_count;
 931   // JVMSpec|           cp_info constant_pool[constant_pool_count-1];
 932   write_u2(checked_cast<u2>(cpool()->length()));
 933   copy_cpool_bytes(writeable_address(cpool_size()));
 934 
 935   // JVMSpec|           u2 access_flags;
 936   write_u2(ik()->access_flags().get_flags() & JVM_RECOGNIZED_CLASS_MODIFIERS);
 937 
 938   // JVMSpec|           u2 this_class;
 939   // JVMSpec|           u2 super_class;
 940   write_u2(class_symbol_to_cpool_index(ik()->name()));
 941   Klass* super_class = ik()->super();
 942   write_u2(super_class == nullptr? 0 :  // zero for java.lang.Object
 943                 class_symbol_to_cpool_index(super_class->name()));
 944 
 945   // JVMSpec|           u2 interfaces_count;
 946   // JVMSpec|           u2 interfaces[interfaces_count];
 947   Array<InstanceKlass*>* interfaces =  ik()->local_interfaces();
 948   int num_interfaces = interfaces->length();
 949   write_u2(checked_cast<u2>(num_interfaces));
 950   for (int index = 0; index < num_interfaces; index++) {
 951     HandleMark hm(thread());
 952     InstanceKlass* iik = interfaces->at(index);
 953     write_u2(class_symbol_to_cpool_index(iik->name()));
 954   }
 955 
 956   // JVMSpec|           u2 fields_count;
 957   // JVMSpec|           field_info fields[fields_count];
 958   write_field_infos();
 959 
 960   // JVMSpec|           u2 methods_count;
 961   // JVMSpec|           method_info methods[methods_count];
 962   write_method_infos();
 963 
 964   // JVMSpec|           u2 attributes_count;
 965   // JVMSpec|           attribute_info attributes[attributes_count];
 966   // JVMSpec|   } /* end ClassFile 8?
 967   write_class_attributes();
 968 }
 969 
 970 address JvmtiClassFileReconstituter::writeable_address(size_t size) {
 971   size_t used_size = _buffer_ptr - _buffer;
 972   if (size + used_size >= _buffer_size) {
 973     // compute the new buffer size: must be at least twice as big as before
 974     // plus whatever new is being used; then convert to nice clean block boundary
 975     size_t new_buffer_size = (size + _buffer_size*2 + 1) / initial_buffer_size
 976                                                          * initial_buffer_size;
 977 
 978     // VM goes belly-up if the memory isn't available, so cannot do OOM processing
 979     _buffer = REALLOC_RESOURCE_ARRAY(u1, _buffer, _buffer_size, new_buffer_size);
 980     _buffer_size = new_buffer_size;
 981     _buffer_ptr = _buffer + used_size;
 982   }
 983   u1* ret_ptr = _buffer_ptr;
 984   _buffer_ptr += size;
 985   return ret_ptr;
 986 }
 987 
 988 void JvmtiClassFileReconstituter::write_attribute_name_index(const char* name) {
 989   TempNewSymbol sym = SymbolTable::probe(name, (int)strlen(name));
 990   assert(sym != nullptr, "attribute name symbol not found");
 991   u2 attr_name_index = symbol_to_cpool_index(sym);
 992   assert(attr_name_index != 0, "attribute name symbol not in constant pool");
 993   write_u2(attr_name_index);
 994 }
 995 
 996 void JvmtiClassFileReconstituter::write_u1(u1 x) {
 997   *writeable_address(1) = x;
 998 }
 999 
1000 void JvmtiClassFileReconstituter::write_u2(u2 x) {
1001   Bytes::put_Java_u2(writeable_address(2), x);
1002 }
1003 
1004 void JvmtiClassFileReconstituter::write_u4(u4 x) {
1005   Bytes::put_Java_u4(writeable_address(4), x);
1006 }
1007 
1008 void JvmtiClassFileReconstituter::write_u8(u8 x) {
1009   Bytes::put_Java_u8(writeable_address(8), x);
1010 }
1011 
1012 void JvmtiClassFileReconstituter::copy_bytecodes(const methodHandle& mh,
1013                                                  unsigned char* bytecodes) {
1014   // use a BytecodeStream to iterate over the bytecodes. JVM/fast bytecodes
1015   // and the breakpoint bytecode are converted to their original bytecodes.
1016 
1017   BytecodeStream bs(mh);
1018 
1019   unsigned char* p = bytecodes;
1020   Bytecodes::Code code;
1021   bool is_rewritten = mh->method_holder()->is_rewritten();
1022 
1023   while ((code = bs.next()) >= 0) {
1024     assert(Bytecodes::is_java_code(code), "sanity check");
1025     assert(code != Bytecodes::_breakpoint, "sanity check");
1026 
1027     // length of bytecode (mnemonic + operands)
1028     address bcp = bs.bcp();
1029     int     len = bs.instruction_size();
1030     assert(len > 0, "length must be > 0");
1031 
1032     // copy the bytecodes
1033     *p = (unsigned char) (bs.is_wide()? Bytecodes::_wide : code);
1034     if (len > 1) {
1035       memcpy(p+1, bcp+1, len-1);
1036     }
1037 
1038     // During linking the get/put and invoke instructions are rewritten
1039     // with an index into the constant pool cache. The original constant
1040     // pool index must be returned to caller.  Rewrite the index.
1041     if (is_rewritten && len > 1) {
1042       bool is_wide = false;
1043       switch (code) {
1044       case Bytecodes::_getstatic       :  // fall through
1045       case Bytecodes::_putstatic       :  // fall through
1046       case Bytecodes::_getfield        :  // fall through
1047       case Bytecodes::_putfield        :  {
1048         int field_index = Bytes::get_native_u2(bcp+1);
1049         u2 pool_index = mh->constants()->resolved_field_entry_at(field_index)->constant_pool_index();
1050         assert(pool_index < mh->constants()->length(), "sanity check");
1051         Bytes::put_Java_u2((address)(p+1), pool_index);     // java byte ordering
1052         break;
1053       }
1054       case Bytecodes::_invokevirtual   :  // fall through
1055       case Bytecodes::_invokespecial   :  // fall through
1056       case Bytecodes::_invokestatic    :  // fall through
1057       case Bytecodes::_invokedynamic   :  // fall through
1058       case Bytecodes::_invokeinterface : {
1059         assert(len == 3 ||
1060                (code == Bytecodes::_invokeinterface && len == 5) ||
1061                (code == Bytecodes::_invokedynamic   && len == 5),
1062                "sanity check");
1063 
1064         int cpci = Bytes::get_native_u2(bcp+1);
1065         bool is_invokedynamic = (code == Bytecodes::_invokedynamic);
1066         int pool_index;
1067         if (is_invokedynamic) {
1068           cpci = Bytes::get_native_u4(bcp+1);
1069           pool_index = mh->constants()->resolved_indy_entry_at(mh->constants()->decode_invokedynamic_index(cpci))->constant_pool_index();
1070         } else {
1071           // cache cannot be pre-fetched since some classes won't have it yet
1072           pool_index = mh->constants()->resolved_method_entry_at(cpci)->constant_pool_index();
1073         }
1074         assert(pool_index < mh->constants()->length(), "sanity check");
1075         Bytes::put_Java_u2((address)(p+1), (u2)pool_index);     // java byte ordering
1076         if (is_invokedynamic)  *(p+3) = *(p+4) = 0;
1077         break;
1078       }
1079       case Bytecodes::_ldc_w:
1080         is_wide = true; // fall through
1081       case Bytecodes::_ldc: {
1082         if (bs.raw_code() == Bytecodes::_fast_aldc || bs.raw_code() == Bytecodes::_fast_aldc_w) {
1083           int cpci = is_wide ? Bytes::get_native_u2(bcp+1) : (u1)(*(bcp+1));
1084           int i = mh->constants()->object_to_cp_index(cpci);
1085           assert(i < mh->constants()->length(), "sanity check");
1086           if (is_wide) {
1087             Bytes::put_Java_u2((address)(p+1), (u2)i);     // java byte ordering
1088           } else {
1089             *(p+1) = (u1)i;
1090           }
1091         }
1092         break;
1093         }
1094       default:
1095         break;
1096       }
1097     }
1098 
1099     p += len;
1100   }
1101 }