1 /*
   2  * Copyright (c) 2005, 2022, 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 "classfile/vmClasses.hpp"
  28 #include "interpreter/bytecodeStream.hpp"
  29 #include "memory/universe.hpp"
  30 #include "oops/fieldStreams.inline.hpp"
  31 #include "oops/recordComponent.hpp"
  32 #include "prims/jvmtiClassFileReconstituter.hpp"
  33 #include "runtime/handles.inline.hpp"
  34 #include "runtime/signature.hpp"
  35 #include "utilities/bytes.hpp"
  36 
  37 // FIXME: add Deprecated attribute
  38 // FIXME: fix Synthetic attribute
  39 // FIXME: per Serguei, add error return handling for ConstantPool::copy_cpool_bytes()
  40 
  41 JvmtiConstantPoolReconstituter::JvmtiConstantPoolReconstituter(InstanceKlass* ik) {
  42   set_error(JVMTI_ERROR_NONE);
  43   _ik = ik;
  44   _cpool = constantPoolHandle(Thread::current(), ik->constants());
  45   _symmap = new SymbolHashMap();
  46   _classmap = new SymbolHashMap();
  47   _cpool_size = _cpool->hash_entries_to(_symmap, _classmap);
  48   if (_cpool_size == 0) {
  49     set_error(JVMTI_ERROR_OUT_OF_MEMORY);
  50   } else if (_cpool_size < 0) {
  51     set_error(JVMTI_ERROR_INTERNAL);
  52   }
  53 }
  54 
  55 // Write the field information portion of ClassFile structure
  56 // JVMSpec|     u2 fields_count;
  57 // JVMSpec|     field_info fields[fields_count];
  58 void JvmtiClassFileReconstituter::write_field_infos() {
  59   HandleMark hm(thread());
  60   Array<AnnotationArray*>* fields_anno = ik()->fields_annotations();
  61   Array<AnnotationArray*>* fields_type_anno = ik()->fields_type_annotations();
  62 
  63   // Compute the real number of Java fields
  64   int java_fields = ik()->java_fields_count();
  65 
  66   write_u2(java_fields);
  67   for (JavaFieldStream fs(ik()); !fs.done(); fs.next()) {
  68     AccessFlags access_flags = fs.access_flags();
  69     int name_index = fs.name_index();
  70     int signature_index = fs.signature_index();
  71     int initial_value_index = fs.initval_index();
  72     guarantee(name_index != 0 && signature_index != 0, "bad constant pool index for field");
  73     // int offset = ik()->field_offset( index );
  74     int generic_signature_index = fs.generic_signature_index();
  75     AnnotationArray* anno = fields_anno == NULL ? NULL : fields_anno->at(fs.index());
  76     AnnotationArray* type_anno = fields_type_anno == NULL ? NULL : fields_type_anno->at(fs.index());
  77 
  78     // JVMSpec|   field_info {
  79     // JVMSpec|         u2 access_flags;
  80     // JVMSpec|         u2 name_index;
  81     // JVMSpec|         u2 descriptor_index;
  82     // JVMSpec|         u2 attributes_count;
  83     // JVMSpec|         attribute_info attributes[attributes_count];
  84     // JVMSpec|   }
  85 
  86     write_u2(access_flags.as_int() & JVM_RECOGNIZED_FIELD_MODIFIERS);
  87     write_u2(name_index);
  88     write_u2(signature_index);
  89     int attr_count = 0;
  90     if (initial_value_index != 0) {
  91       ++attr_count;
  92     }
  93     if (access_flags.is_synthetic()) {
  94       // ++attr_count;
  95     }
  96     if (generic_signature_index != 0) {
  97       ++attr_count;
  98     }
  99     if (anno != NULL) {
 100       ++attr_count;     // has RuntimeVisibleAnnotations attribute
 101     }
 102     if (type_anno != NULL) {
 103       ++attr_count;     // has RuntimeVisibleTypeAnnotations attribute
 104     }
 105 
 106     write_u2(attr_count);
 107 
 108     if (initial_value_index != 0) {
 109       write_attribute_name_index("ConstantValue");
 110       write_u4(2); //length always 2
 111       write_u2(initial_value_index);
 112     }
 113     if (access_flags.is_synthetic()) {
 114       // write_synthetic_attribute();
 115     }
 116     if (generic_signature_index != 0) {
 117       write_signature_attribute(generic_signature_index);
 118     }
 119     if (anno != NULL) {
 120       write_annotations_attribute("RuntimeVisibleAnnotations", anno);
 121     }
 122     if (type_anno != NULL) {
 123       write_annotations_attribute("RuntimeVisibleTypeAnnotations", type_anno);
 124     }
 125   }
 126 }
 127 
 128 // Write Code attribute
 129 // JVMSpec|   Code_attribute {
 130 // JVMSpec|     u2 attribute_name_index;
 131 // JVMSpec|     u4 attribute_length;
 132 // JVMSpec|     u2 max_stack;
 133 // JVMSpec|     u2 max_locals;
 134 // JVMSpec|     u4 code_length;
 135 // JVMSpec|     u1 code[code_length];
 136 // JVMSpec|     u2 exception_table_length;
 137 // JVMSpec|     {       u2 start_pc;
 138 // JVMSpec|             u2 end_pc;
 139 // JVMSpec|             u2  handler_pc;
 140 // JVMSpec|             u2  catch_type;
 141 // JVMSpec|     }       exception_table[exception_table_length];
 142 // JVMSpec|     u2 attributes_count;
 143 // JVMSpec|     attribute_info attributes[attributes_count];
 144 // JVMSpec|   }
 145 void JvmtiClassFileReconstituter::write_code_attribute(const methodHandle& method) {
 146   ConstMethod* const_method = method->constMethod();
 147   u2 line_num_cnt = 0;
 148   int stackmap_len = 0;
 149   int local_variable_table_length = 0;
 150   int local_variable_type_table_length = 0;
 151 
 152   // compute number and length of attributes
 153   int attr_count = 0;
 154   int attr_size = 0;
 155   if (const_method->has_linenumber_table()) {
 156     line_num_cnt = line_number_table_entries(method);
 157     if (line_num_cnt != 0) {
 158       ++attr_count;
 159       // Compute the complete size of the line number table attribute:
 160       //      LineNumberTable_attribute {
 161       //        u2 attribute_name_index;
 162       //        u4 attribute_length;
 163       //        u2 line_number_table_length;
 164       //        {  u2 start_pc;
 165       //           u2 line_number;
 166       //        } line_number_table[line_number_table_length];
 167       //      }
 168       attr_size += 2 + 4 + 2 + line_num_cnt * (2 + 2);
 169     }
 170   }
 171   if (method->has_stackmap_table()) {
 172     stackmap_len = method->stackmap_data()->length();
 173     if (stackmap_len != 0) {
 174       ++attr_count;
 175       // Compute the  size of the stack map table attribute (VM stores raw):
 176       //      StackMapTable_attribute {
 177       //        u2 attribute_name_index;
 178       //        u4 attribute_length;
 179       //        u2 number_of_entries;
 180       //        stack_map_frame_entries[number_of_entries];
 181       //      }
 182       attr_size += 2 + 4 + stackmap_len;
 183     }
 184   }
 185   if (method->has_localvariable_table()) {
 186     local_variable_table_length = method->localvariable_table_length();
 187     if (local_variable_table_length != 0) {
 188       ++attr_count;
 189       // Compute the size of the local variable table attribute (VM stores raw):
 190       // LocalVariableTable_attribute {
 191       //   u2 attribute_name_index;
 192       //   u4 attribute_length;
 193       //   u2 local_variable_table_length;
 194       //   {
 195       //     u2 start_pc;
 196       //     u2 length;
 197       //     u2 name_index;
 198       //     u2 descriptor_index;
 199       //     u2 index;
 200       //   }
 201       attr_size += 2 + 4 + 2 + local_variable_table_length * (2 + 2 + 2 + 2 + 2);
 202 
 203       // Local variables with generic signatures must have LVTT entries
 204       LocalVariableTableElement *elem = method->localvariable_table_start();
 205       for (int idx = 0; idx < local_variable_table_length; idx++) {
 206         if (elem[idx].signature_cp_index != 0) {
 207           local_variable_type_table_length++;
 208         }
 209       }
 210 
 211       if (local_variable_type_table_length != 0) {
 212         ++attr_count;
 213         // Compute the size of the local variable type table attribute (VM stores raw):
 214         // LocalVariableTypeTable_attribute {
 215         //   u2 attribute_name_index;
 216         //   u4 attribute_length;
 217         //   u2 local_variable_type_table_length;
 218         //   {
 219         //     u2 start_pc;
 220         //     u2 length;
 221         //     u2 name_index;
 222         //     u2 signature_index;
 223         //     u2 index;
 224         //   }
 225         attr_size += 2 + 4 + 2 + local_variable_type_table_length * (2 + 2 + 2 + 2 + 2);
 226       }
 227     }
 228   }
 229 
 230   ExceptionTable exception_table(method());
 231   int exception_table_length = exception_table.length();
 232   int code_size = const_method->code_size();
 233   int size =
 234     2+2+4 +                                // max_stack, max_locals, code_length
 235     code_size +                            // code
 236     2 +                                    // exception_table_length
 237     (2+2+2+2) * exception_table_length +   // exception_table
 238     2 +                                    // attributes_count
 239     attr_size;                             // attributes
 240 
 241   write_attribute_name_index("Code");
 242   write_u4(size);
 243   write_u2(method->verifier_max_stack());
 244   write_u2(method->max_locals());
 245   write_u4(code_size);
 246   copy_bytecodes(method, (unsigned char*)writeable_address(code_size));
 247   write_u2(exception_table_length);
 248   for (int index = 0; index < exception_table_length; index++) {
 249     write_u2(exception_table.start_pc(index));
 250     write_u2(exception_table.end_pc(index));
 251     write_u2(exception_table.handler_pc(index));
 252     write_u2(exception_table.catch_type_index(index));
 253   }
 254   write_u2(attr_count);
 255   if (line_num_cnt != 0) {
 256     write_line_number_table_attribute(method, line_num_cnt);
 257   }
 258   if (stackmap_len != 0) {
 259     write_stackmap_table_attribute(method, stackmap_len);
 260   }
 261   if (local_variable_table_length != 0) {
 262     write_local_variable_table_attribute(method, local_variable_table_length);
 263   }
 264   if (local_variable_type_table_length != 0) {
 265     write_local_variable_type_table_attribute(method, local_variable_type_table_length);
 266   }
 267 }
 268 
 269 // Write Exceptions attribute
 270 // JVMSpec|   Exceptions_attribute {
 271 // JVMSpec|     u2 attribute_name_index;
 272 // JVMSpec|     u4 attribute_length;
 273 // JVMSpec|     u2 number_of_exceptions;
 274 // JVMSpec|     u2 exception_index_table[number_of_exceptions];
 275 // JVMSpec|   }
 276 void JvmtiClassFileReconstituter::write_exceptions_attribute(ConstMethod* const_method) {
 277   CheckedExceptionElement* checked_exceptions = const_method->checked_exceptions_start();
 278   int checked_exceptions_length = const_method->checked_exceptions_length();
 279   int size =
 280     2 +                                    // number_of_exceptions
 281     2 * checked_exceptions_length;         // exception_index_table
 282 
 283   write_attribute_name_index("Exceptions");
 284   write_u4(size);
 285   write_u2(checked_exceptions_length);
 286   for (int index = 0; index < checked_exceptions_length; index++) {
 287     write_u2(checked_exceptions[index].class_cp_index);
 288   }
 289 }
 290 
 291 // Write MethodParameters attribute
 292 // JVMSpec|   MethodParameters_attribute {
 293 // JVMSpec|     u2 attribute_name_index;
 294 // JVMSpec|     u4 attribute_length;
 295 // JVMSpec|     u1 parameters_count;
 296 // JVMSpec|     {   u2 name_index;
 297 // JVMSpec|         u2 access_flags;
 298 // JVMSpec|     } parameters[parameters_count];
 299 // JVMSpec|   }
 300 void JvmtiClassFileReconstituter::write_method_parameter_attribute(const ConstMethod* const_method) {
 301   const MethodParametersElement *parameters = const_method->method_parameters_start();
 302   int length = const_method->method_parameters_length();
 303   assert(length <= max_jubyte, "must fit u1");
 304   int size = 1                  // parameters_count
 305            + (2 + 2) * length;  // parameters
 306 
 307   write_attribute_name_index("MethodParameters");
 308   write_u4(size);
 309   write_u1(length);
 310   for (int index = 0; index < length; index++) {
 311     write_u2(parameters[index].name_cp_index);
 312     write_u2(parameters[index].flags);
 313   }
 314 }
 315 
 316 // Write SourceFile attribute
 317 // JVMSpec|   SourceFile_attribute {
 318 // JVMSpec|     u2 attribute_name_index;
 319 // JVMSpec|     u4 attribute_length;
 320 // JVMSpec|     u2 sourcefile_index;
 321 // JVMSpec|   }
 322 void JvmtiClassFileReconstituter::write_source_file_attribute() {
 323   assert(ik()->source_file_name() != NULL, "caller must check");
 324 
 325   write_attribute_name_index("SourceFile");
 326   write_u4(2);  // always length 2
 327   write_u2(symbol_to_cpool_index(ik()->source_file_name()));
 328 }
 329 
 330 // Write SourceDebugExtension attribute
 331 // JSR45|   SourceDebugExtension_attribute {
 332 // JSR45|       u2 attribute_name_index;
 333 // JSR45|       u4 attribute_length;
 334 // JSR45|       u1 debug_extension[attribute_length];
 335 // JSR45|   }
 336 void JvmtiClassFileReconstituter::write_source_debug_extension_attribute() {
 337   assert(ik()->source_debug_extension() != NULL, "caller must check");
 338 
 339   write_attribute_name_index("SourceDebugExtension");
 340   int len = (int)strlen(ik()->source_debug_extension());
 341   write_u4(len);
 342   u1* ext = (u1*)ik()->source_debug_extension();
 343   for (int i=0; i<len; i++) {
 344     write_u1(ext[i]);
 345   }
 346 }
 347 
 348 // Write (generic) Signature attribute
 349 // JVMSpec|   Signature_attribute {
 350 // JVMSpec|     u2 attribute_name_index;
 351 // JVMSpec|     u4 attribute_length;
 352 // JVMSpec|     u2 signature_index;
 353 // JVMSpec|   }
 354 void JvmtiClassFileReconstituter::write_signature_attribute(u2 generic_signature_index) {
 355   write_attribute_name_index("Signature");
 356   write_u4(2);  // always length 2
 357   write_u2(generic_signature_index);
 358 }
 359 
 360 // Compute the number of entries in the InnerClasses attribute
 361 u2 JvmtiClassFileReconstituter::inner_classes_attribute_length() {
 362   InnerClassesIterator iter(ik());
 363   return iter.length();
 364 }
 365 
 366 // Write an annotation attribute.  The VM stores them in raw form, so all we need
 367 // to do is add the attrubute name and fill in the length.
 368 // JSR202|   *Annotations_attribute {
 369 // JSR202|     u2 attribute_name_index;
 370 // JSR202|     u4 attribute_length;
 371 // JSR202|     ...
 372 // JSR202|   }
 373 void JvmtiClassFileReconstituter::write_annotations_attribute(const char* attr_name,
 374                                                               AnnotationArray* annos) {
 375   u4 length = annos->length();
 376   write_attribute_name_index(attr_name);
 377   write_u4(length);
 378   memcpy(writeable_address(length), annos->adr_at(0), length);
 379 }
 380 
 381 //  BootstrapMethods_attribute {
 382 //    u2 attribute_name_index;
 383 //    u4 attribute_length;
 384 //    u2 num_bootstrap_methods;
 385 //    {   u2 bootstrap_method_ref;
 386 //        u2 num_bootstrap_arguments;
 387 //        u2 bootstrap_arguments[num_bootstrap_arguments];
 388 //    } bootstrap_methods[num_bootstrap_methods];
 389 //  }
 390 void JvmtiClassFileReconstituter::write_bootstrapmethod_attribute() {
 391   Array<u2>* operands = cpool()->operands();
 392   write_attribute_name_index("BootstrapMethods");
 393   int num_bootstrap_methods = ConstantPool::operand_array_length(operands);
 394 
 395   // calculate length of attribute
 396   int length = sizeof(u2); // num_bootstrap_methods
 397   for (int n = 0; n < num_bootstrap_methods; n++) {
 398     u2 num_bootstrap_arguments = cpool()->operand_argument_count_at(n);
 399     length += sizeof(u2); // bootstrap_method_ref
 400     length += sizeof(u2); // num_bootstrap_arguments
 401     length += sizeof(u2) * num_bootstrap_arguments; // bootstrap_arguments[num_bootstrap_arguments]
 402   }
 403   write_u4(length);
 404 
 405   // write attribute
 406   write_u2(num_bootstrap_methods);
 407   for (int n = 0; n < num_bootstrap_methods; n++) {
 408     u2 bootstrap_method_ref = cpool()->operand_bootstrap_method_ref_index_at(n);
 409     u2 num_bootstrap_arguments = cpool()->operand_argument_count_at(n);
 410     write_u2(bootstrap_method_ref);
 411     write_u2(num_bootstrap_arguments);
 412     for (int arg = 0; arg < num_bootstrap_arguments; arg++) {
 413       u2 bootstrap_argument = cpool()->operand_argument_index_at(n, arg);
 414       write_u2(bootstrap_argument);
 415     }
 416   }
 417 }
 418 
 419 //  NestHost_attribute {
 420 //    u2 attribute_name_index;
 421 //    u4 attribute_length;
 422 //    u2 host_class_index;
 423 //  }
 424 void JvmtiClassFileReconstituter::write_nest_host_attribute() {
 425   int length = sizeof(u2);
 426   int host_class_index = ik()->nest_host_index();
 427 
 428   write_attribute_name_index("NestHost");
 429   write_u4(length);
 430   write_u2(host_class_index);
 431 }
 432 
 433 //  NestMembers_attribute {
 434 //    u2 attribute_name_index;
 435 //    u4 attribute_length;
 436 //    u2 number_of_classes;
 437 //    u2 classes[number_of_classes];
 438 //  }
 439 void JvmtiClassFileReconstituter::write_nest_members_attribute() {
 440   Array<u2>* nest_members = ik()->nest_members();
 441   int number_of_classes = nest_members->length();
 442   int length = sizeof(u2) * (1 + number_of_classes);
 443 
 444   write_attribute_name_index("NestMembers");
 445   write_u4(length);
 446   write_u2(number_of_classes);
 447   for (int i = 0; i < number_of_classes; i++) {
 448     u2 class_cp_index = nest_members->at(i);
 449     write_u2(class_cp_index);
 450   }
 451 }
 452 
 453 //  PermittedSubclasses {
 454 //    u2 attribute_name_index;
 455 //    u4 attribute_length;
 456 //    u2 number_of_classes;
 457 //    u2 classes[number_of_classes];
 458 //  }
 459 void JvmtiClassFileReconstituter::write_permitted_subclasses_attribute() {
 460   Array<u2>* permitted_subclasses = ik()->permitted_subclasses();
 461   int number_of_classes = permitted_subclasses->length();
 462   int length = sizeof(u2) * (1 + number_of_classes); // '1 +' is for number_of_classes field
 463 
 464   write_attribute_name_index("PermittedSubclasses");
 465   write_u4(length);
 466   write_u2(number_of_classes);
 467   for (int i = 0; i < number_of_classes; i++) {
 468     u2 class_cp_index = permitted_subclasses->at(i);
 469     write_u2(class_cp_index);
 470   }
 471 }
 472 
 473 //  Record {
 474 //    u2 attribute_name_index;
 475 //    u4 attribute_length;
 476 //    u2 components_count;
 477 //    component_info components[components_count];
 478 //  }
 479 //  component_info {
 480 //    u2 name_index;
 481 //    u2 descriptor_index
 482 //    u2 attributes_count;
 483 //    attribute_info_attributes[attributes_count];
 484 //  }
 485 void JvmtiClassFileReconstituter::write_record_attribute() {
 486   Array<RecordComponent*>* components = ik()->record_components();
 487   int number_of_components = components->length();
 488 
 489   // Each component has a u2 for name, descr, attribute count
 490   int length = sizeof(u2) + (sizeof(u2) * 3 * number_of_components);
 491   for (int x = 0; x < number_of_components; x++) {
 492     RecordComponent* component = components->at(x);
 493     if (component->generic_signature_index() != 0) {
 494       length += 8; // Signature attribute size
 495       assert(component->attributes_count() > 0, "Bad component attributes count");
 496     }
 497     if (component->annotations() != NULL) {
 498       length += 6 + component->annotations()->length();
 499     }
 500     if (component->type_annotations() != NULL) {
 501       length += 6 + component->type_annotations()->length();
 502     }
 503   }
 504 
 505   write_attribute_name_index("Record");
 506   write_u4(length);
 507   write_u2(number_of_components);
 508   for (int i = 0; i < number_of_components; i++) {
 509     RecordComponent* component = components->at(i);
 510     write_u2(component->name_index());
 511     write_u2(component->descriptor_index());
 512     write_u2(component->attributes_count());
 513     if (component->generic_signature_index() != 0) {
 514       write_signature_attribute(component->generic_signature_index());
 515     }
 516     if (component->annotations() != NULL) {
 517       write_annotations_attribute("RuntimeVisibleAnnotations", component->annotations());
 518     }
 519     if (component->type_annotations() != NULL) {
 520       write_annotations_attribute("RuntimeVisibleTypeAnnotations", component->type_annotations());
 521     }
 522   }
 523 }
 524 
 525 // Write InnerClasses attribute
 526 // JVMSpec|   InnerClasses_attribute {
 527 // JVMSpec|     u2 attribute_name_index;
 528 // JVMSpec|     u4 attribute_length;
 529 // JVMSpec|     u2 number_of_classes;
 530 // JVMSpec|     {  u2 inner_class_info_index;
 531 // JVMSpec|        u2 outer_class_info_index;
 532 // JVMSpec|        u2 inner_name_index;
 533 // JVMSpec|        u2 inner_class_access_flags;
 534 // JVMSpec|     } classes[number_of_classes];
 535 // JVMSpec|   }
 536 void JvmtiClassFileReconstituter::write_inner_classes_attribute(int length) {
 537   InnerClassesIterator iter(ik());
 538   guarantee(iter.length() != 0 && iter.length() == length,
 539             "caller must check");
 540   u2 entry_count = length / InstanceKlass::inner_class_next_offset;
 541   u4 size = 2 + entry_count * (2+2+2+2);
 542 
 543   write_attribute_name_index("InnerClasses");
 544   write_u4(size);
 545   write_u2(entry_count);
 546   for (; !iter.done(); iter.next()) {
 547     write_u2(iter.inner_class_info_index());
 548     write_u2(iter.outer_class_info_index());
 549     write_u2(iter.inner_name_index());
 550     write_u2(iter.inner_access_flags());
 551   }
 552 }
 553 
 554 // Write Synthetic attribute
 555 // JVMSpec|   Synthetic_attribute {
 556 // JVMSpec|     u2 attribute_name_index;
 557 // JVMSpec|     u4 attribute_length;
 558 // JVMSpec|   }
 559 void JvmtiClassFileReconstituter::write_synthetic_attribute() {
 560   write_attribute_name_index("Synthetic");
 561   write_u4(0); //length always zero
 562 }
 563 
 564 // Compute size of LineNumberTable
 565 u2 JvmtiClassFileReconstituter::line_number_table_entries(const methodHandle& method) {
 566   // The line number table is compressed so we don't know how big it is until decompressed.
 567   // Decompression is really fast so we just do it twice.
 568   u2 num_entries = 0;
 569   CompressedLineNumberReadStream stream(method->compressed_linenumber_table());
 570   while (stream.read_pair()) {
 571     num_entries++;
 572   }
 573   return num_entries;
 574 }
 575 
 576 // Write LineNumberTable attribute
 577 // JVMSpec|   LineNumberTable_attribute {
 578 // JVMSpec|     u2 attribute_name_index;
 579 // JVMSpec|     u4 attribute_length;
 580 // JVMSpec|     u2 line_number_table_length;
 581 // JVMSpec|     {  u2 start_pc;
 582 // JVMSpec|        u2 line_number;
 583 // JVMSpec|     } line_number_table[line_number_table_length];
 584 // JVMSpec|   }
 585 void JvmtiClassFileReconstituter::write_line_number_table_attribute(const methodHandle& method,
 586                                                                     u2 num_entries) {
 587 
 588   write_attribute_name_index("LineNumberTable");
 589   write_u4(2 + num_entries * (2 + 2));
 590   write_u2(num_entries);
 591 
 592   CompressedLineNumberReadStream stream(method->compressed_linenumber_table());
 593   while (stream.read_pair()) {
 594     write_u2(stream.bci());
 595     write_u2(stream.line());
 596   }
 597 }
 598 
 599 // Write LocalVariableTable attribute
 600 // JVMSpec|   LocalVariableTable_attribute {
 601 // JVMSpec|     u2 attribute_name_index;
 602 // JVMSpec|     u4 attribute_length;
 603 // JVMSpec|     u2 local_variable_table_length;
 604 // JVMSpec|     {  u2 start_pc;
 605 // JVMSpec|       u2 length;
 606 // JVMSpec|       u2 name_index;
 607 // JVMSpec|       u2 descriptor_index;
 608 // JVMSpec|       u2 index;
 609 // JVMSpec|     } local_variable_table[local_variable_table_length];
 610 // JVMSpec|   }
 611 void JvmtiClassFileReconstituter::write_local_variable_table_attribute(const methodHandle& method, u2 num_entries) {
 612     write_attribute_name_index("LocalVariableTable");
 613     write_u4(2 + num_entries * (2 + 2 + 2 + 2 + 2));
 614     write_u2(num_entries);
 615 
 616     assert(method->localvariable_table_length() == num_entries, "just checking");
 617 
 618     LocalVariableTableElement *elem = method->localvariable_table_start();
 619     for (int j=0; j<method->localvariable_table_length(); j++) {
 620       write_u2(elem->start_bci);
 621       write_u2(elem->length);
 622       write_u2(elem->name_cp_index);
 623       write_u2(elem->descriptor_cp_index);
 624       write_u2(elem->slot);
 625       elem++;
 626     }
 627 }
 628 
 629 // Write LocalVariableTypeTable attribute
 630 // JVMSpec|   LocalVariableTypeTable_attribute {
 631 // JVMSpec|     u2 attribute_name_index;
 632 // JVMSpec|     u4 attribute_length;
 633 // JVMSpec|     u2 local_variable_type_table_length;
 634 // JVMSpec|     { u2 start_pc;
 635 // JVMSpec|       u2 length;
 636 // JVMSpec|       u2 name_index;
 637 // JVMSpec|       u2 signature_index;
 638 // JVMSpec|       u2 index;
 639 // JVMSpec|     } local_variable_type_table[local_variable_type_table_length];
 640 // JVMSpec|   }
 641 void JvmtiClassFileReconstituter::write_local_variable_type_table_attribute(const methodHandle& method, u2 num_entries) {
 642     write_attribute_name_index("LocalVariableTypeTable");
 643     write_u4(2 + num_entries * (2 + 2 + 2 + 2 + 2));
 644     write_u2(num_entries);
 645 
 646     LocalVariableTableElement *elem = method->localvariable_table_start();
 647     for (int j=0; j<method->localvariable_table_length(); j++) {
 648       if (elem->signature_cp_index > 0) {
 649         // Local variable has a generic signature - write LVTT attribute entry
 650         write_u2(elem->start_bci);
 651         write_u2(elem->length);
 652         write_u2(elem->name_cp_index);
 653         write_u2(elem->signature_cp_index);
 654         write_u2(elem->slot);
 655         num_entries--;
 656       }
 657       elem++;
 658     }
 659     assert(num_entries == 0, "just checking");
 660 }
 661 
 662 // Write stack map table attribute
 663 // JSR-202|   StackMapTable_attribute {
 664 // JSR-202|     u2 attribute_name_index;
 665 // JSR-202|     u4 attribute_length;
 666 // JSR-202|     u2 number_of_entries;
 667 // JSR-202|     stack_map_frame_entries[number_of_entries];
 668 // JSR-202|   }
 669 void JvmtiClassFileReconstituter::write_stackmap_table_attribute(const methodHandle& method,
 670                                                                  int stackmap_len) {
 671 
 672   write_attribute_name_index("StackMapTable");
 673   write_u4(stackmap_len);
 674   memcpy(
 675     writeable_address(stackmap_len),
 676     (void*)(method->stackmap_data()->adr_at(0)),
 677     stackmap_len);
 678 }
 679 
 680 // Write one method_info structure
 681 // JVMSpec|   method_info {
 682 // JVMSpec|     u2 access_flags;
 683 // JVMSpec|     u2 name_index;
 684 // JVMSpec|     u2 descriptor_index;
 685 // JVMSpec|     u2 attributes_count;
 686 // JVMSpec|     attribute_info attributes[attributes_count];
 687 // JVMSpec|   }
 688 void JvmtiClassFileReconstituter::write_method_info(const methodHandle& method) {
 689   AccessFlags access_flags = method->access_flags();
 690   ConstMethod* const_method = method->constMethod();
 691   u2 generic_signature_index = const_method->generic_signature_index();
 692   AnnotationArray* anno = method->annotations();
 693   AnnotationArray* param_anno = method->parameter_annotations();
 694   AnnotationArray* default_anno = method->annotation_default();
 695   AnnotationArray* type_anno = method->type_annotations();
 696 
 697   // skip generated default interface methods
 698   if (method->is_overpass()) {
 699     return;
 700   }
 701 
 702   write_u2(access_flags.get_flags() & JVM_RECOGNIZED_METHOD_MODIFIERS);
 703   write_u2(const_method->name_index());
 704   write_u2(const_method->signature_index());
 705 
 706   // write attributes in the same order javac does, so we can test with byte for
 707   // byte comparison
 708   int attr_count = 0;
 709   if (const_method->code_size() != 0) {
 710     ++attr_count;     // has Code attribute
 711   }
 712   if (const_method->has_checked_exceptions()) {
 713     ++attr_count;     // has Exceptions attribute
 714   }
 715   if (default_anno != NULL) {
 716     ++attr_count;     // has AnnotationDefault attribute
 717   }
 718   if (const_method->has_method_parameters()) {
 719     ++attr_count;     // has MethodParameters attribute
 720   }
 721   // Deprecated attribute would go here
 722   if (access_flags.is_synthetic()) { // FIXME
 723     // ++attr_count;
 724   }
 725   if (generic_signature_index != 0) {
 726     ++attr_count;
 727   }
 728   if (anno != NULL) {
 729     ++attr_count;     // has RuntimeVisibleAnnotations attribute
 730   }
 731   if (param_anno != NULL) {
 732     ++attr_count;     // has RuntimeVisibleParameterAnnotations attribute
 733   }
 734   if (type_anno != NULL) {
 735     ++attr_count;     // has RuntimeVisibleTypeAnnotations attribute
 736   }
 737 
 738   write_u2(attr_count);
 739   if (const_method->code_size() > 0) {
 740     write_code_attribute(method);
 741   }
 742   if (const_method->has_checked_exceptions()) {
 743     write_exceptions_attribute(const_method);
 744   }
 745   if (default_anno != NULL) {
 746     write_annotations_attribute("AnnotationDefault", default_anno);
 747   }
 748   if (const_method->has_method_parameters()) {
 749     write_method_parameter_attribute(const_method);
 750   }
 751   // Deprecated attribute would go here
 752   if (access_flags.is_synthetic()) {
 753     // write_synthetic_attribute();
 754   }
 755   if (generic_signature_index != 0) {
 756     write_signature_attribute(generic_signature_index);
 757   }
 758   if (anno != NULL) {
 759     write_annotations_attribute("RuntimeVisibleAnnotations", anno);
 760   }
 761   if (param_anno != NULL) {
 762     write_annotations_attribute("RuntimeVisibleParameterAnnotations", param_anno);
 763   }
 764   if (type_anno != NULL) {
 765     write_annotations_attribute("RuntimeVisibleTypeAnnotations", type_anno);
 766   }
 767 }
 768 
 769 // Write the class attributes portion of ClassFile structure
 770 // JVMSpec|     u2 attributes_count;
 771 // JVMSpec|     attribute_info attributes[attributes_count];
 772 void JvmtiClassFileReconstituter::write_class_attributes() {
 773   u2 inner_classes_length = inner_classes_attribute_length();
 774   Symbol* generic_signature = ik()->generic_signature();
 775   AnnotationArray* anno = ik()->class_annotations();
 776   AnnotationArray* type_anno = ik()->class_type_annotations();
 777 
 778   int attr_count = 0;
 779   if (generic_signature != NULL) {
 780     ++attr_count;
 781   }
 782   if (ik()->source_file_name() != NULL) {
 783     ++attr_count;
 784   }
 785   if (ik()->source_debug_extension() != NULL) {
 786     ++attr_count;
 787   }
 788   if (inner_classes_length > 0) {
 789     ++attr_count;
 790   }
 791   if (anno != NULL) {
 792     ++attr_count;     // has RuntimeVisibleAnnotations attribute
 793   }
 794   if (type_anno != NULL) {
 795     ++attr_count;     // has RuntimeVisibleTypeAnnotations attribute
 796   }
 797   if (cpool()->operands() != NULL) {
 798     ++attr_count;
 799   }
 800   if (ik()->nest_host_index() != 0) {
 801     ++attr_count;
 802   }
 803   if (ik()->nest_members() != Universe::the_empty_short_array()) {
 804     ++attr_count;
 805   }
 806   if (ik()->permitted_subclasses() != Universe::the_empty_short_array()) {
 807     ++attr_count;
 808   }
 809   if (ik()->record_components() != NULL) {
 810     ++attr_count;
 811   }
 812 
 813   write_u2(attr_count);
 814 
 815   if (generic_signature != NULL) {
 816     write_signature_attribute(symbol_to_cpool_index(generic_signature));
 817   }
 818   if (ik()->source_file_name() != NULL) {
 819     write_source_file_attribute();
 820   }
 821   if (ik()->source_debug_extension() != NULL) {
 822     write_source_debug_extension_attribute();
 823   }
 824   if (anno != NULL) {
 825     write_annotations_attribute("RuntimeVisibleAnnotations", anno);
 826   }
 827   if (type_anno != NULL) {
 828     write_annotations_attribute("RuntimeVisibleTypeAnnotations", type_anno);
 829   }
 830   if (ik()->nest_host_index() != 0) {
 831     write_nest_host_attribute();
 832   }
 833   if (ik()->nest_members() != Universe::the_empty_short_array()) {
 834     write_nest_members_attribute();
 835   }
 836   if (ik()->permitted_subclasses() != Universe::the_empty_short_array()) {
 837     write_permitted_subclasses_attribute();
 838   }
 839   if (ik()->record_components() != NULL) {
 840     write_record_attribute();
 841   }
 842   if (cpool()->operands() != NULL) {
 843     write_bootstrapmethod_attribute();
 844   }
 845   if (inner_classes_length > 0) {
 846     write_inner_classes_attribute(inner_classes_length);
 847   }
 848 }
 849 
 850 // Write the method information portion of ClassFile structure
 851 // JVMSpec|     u2 methods_count;
 852 // JVMSpec|     method_info methods[methods_count];
 853 void JvmtiClassFileReconstituter::write_method_infos() {
 854   HandleMark hm(thread());
 855   Array<Method*>* methods = ik()->methods();
 856   int num_methods = methods->length();
 857   int num_overpass = 0;
 858 
 859   // count the generated default interface methods
 860   // these will not be re-created by write_method_info
 861   // and should not be included in the total count
 862   for (int index = 0; index < num_methods; index++) {
 863     Method* method = methods->at(index);
 864     if (method->is_overpass()) {
 865       num_overpass++;
 866     }
 867   }
 868 
 869   write_u2(num_methods - num_overpass);
 870   if (JvmtiExport::can_maintain_original_method_order()) {
 871     int index;
 872     int original_index;
 873     intArray method_order(num_methods, num_methods, 0);
 874 
 875     // invert the method order mapping
 876     for (index = 0; index < num_methods; index++) {
 877       original_index = ik()->method_ordering()->at(index);
 878       assert(original_index >= 0 && original_index < num_methods,
 879              "invalid original method index");
 880       method_order.at_put(original_index, index);
 881     }
 882 
 883     // write in original order
 884     for (original_index = 0; original_index < num_methods; original_index++) {
 885       index = method_order.at(original_index);
 886       methodHandle method(thread(), methods->at(index));
 887       write_method_info(method);
 888     }
 889   } else {
 890     // method order not preserved just dump the method infos
 891     for (int index = 0; index < num_methods; index++) {
 892       methodHandle method(thread(), methods->at(index));
 893       write_method_info(method);
 894     }
 895   }
 896 }
 897 
 898 void JvmtiClassFileReconstituter::write_class_file_format() {
 899   ReallocMark();
 900 
 901   // JVMSpec|   ClassFile {
 902   // JVMSpec|           u4 magic;
 903   write_u4(0xCAFEBABE);
 904 
 905   // JVMSpec|           u2 minor_version;
 906   // JVMSpec|           u2 major_version;
 907   write_u2(ik()->minor_version());
 908   u2 major = ik()->major_version();
 909   write_u2(major);
 910 
 911   // JVMSpec|           u2 constant_pool_count;
 912   // JVMSpec|           cp_info constant_pool[constant_pool_count-1];
 913   write_u2(cpool()->length());
 914   copy_cpool_bytes(writeable_address(cpool_size()));
 915 
 916   // JVMSpec|           u2 access_flags;
 917   write_u2(ik()->access_flags().get_flags() & (JVM_RECOGNIZED_CLASS_MODIFIERS | JVM_ACC_PRIMITIVE | JVM_ACC_VALUE | JVM_ACC_PERMITS_VALUE));
 918   // JVMSpec|           u2 this_class;
 919   // JVMSpec|           u2 super_class;
 920   write_u2(class_symbol_to_cpool_index(ik()->name()));
 921   Klass* super_class = ik()->super();
 922   write_u2(super_class == NULL? 0 :  // zero for java.lang.Object
 923                 class_symbol_to_cpool_index(super_class->name()));
 924 
 925   // JVMSpec|           u2 interfaces_count;
 926   // JVMSpec|           u2 interfaces[interfaces_count];
 927   Array<InstanceKlass*>* interfaces =  ik()->local_interfaces();
 928   int num_interfaces = interfaces->length();
 929   write_u2(num_interfaces);
 930 
 931   for (int index = 0; index < num_interfaces; index++) {
 932     HandleMark hm(thread());
 933     InstanceKlass* iik = interfaces->at(index);
 934     write_u2(class_symbol_to_cpool_index(iik->name()));
 935   }
 936 
 937   // JVMSpec|           u2 fields_count;
 938   // JVMSpec|           field_info fields[fields_count];
 939   write_field_infos();
 940 
 941   // JVMSpec|           u2 methods_count;
 942   // JVMSpec|           method_info methods[methods_count];
 943   write_method_infos();
 944 
 945   // JVMSpec|           u2 attributes_count;
 946   // JVMSpec|           attribute_info attributes[attributes_count];
 947   // JVMSpec|   } /* end ClassFile 8?
 948   write_class_attributes();
 949 }
 950 
 951 address JvmtiClassFileReconstituter::writeable_address(size_t size) {
 952   size_t used_size = _buffer_ptr - _buffer;
 953   if (size + used_size >= _buffer_size) {
 954     // compute the new buffer size: must be at least twice as big as before
 955     // plus whatever new is being used; then convert to nice clean block boundary
 956     size_t new_buffer_size = (size + _buffer_size*2 + 1) / initial_buffer_size
 957                                                          * initial_buffer_size;
 958 
 959     // VM goes belly-up if the memory isn't available, so cannot do OOM processing
 960     _buffer = REALLOC_RESOURCE_ARRAY(u1, _buffer, _buffer_size, new_buffer_size);
 961     _buffer_size = new_buffer_size;
 962     _buffer_ptr = _buffer + used_size;
 963   }
 964   u1* ret_ptr = _buffer_ptr;
 965   _buffer_ptr += size;
 966   return ret_ptr;
 967 }
 968 
 969 void JvmtiClassFileReconstituter::write_attribute_name_index(const char* name) {
 970   TempNewSymbol sym = SymbolTable::probe(name, (int)strlen(name));
 971   assert(sym != NULL, "attribute name symbol not found");
 972   u2 attr_name_index = symbol_to_cpool_index(sym);
 973   assert(attr_name_index != 0, "attribute name symbol not in constant pool");
 974   write_u2(attr_name_index);
 975 }
 976 
 977 void JvmtiClassFileReconstituter::write_u1(u1 x) {
 978   *writeable_address(1) = x;
 979 }
 980 
 981 void JvmtiClassFileReconstituter::write_u2(u2 x) {
 982   Bytes::put_Java_u2(writeable_address(2), x);
 983 }
 984 
 985 void JvmtiClassFileReconstituter::write_u4(u4 x) {
 986   Bytes::put_Java_u4(writeable_address(4), x);
 987 }
 988 
 989 void JvmtiClassFileReconstituter::write_u8(u8 x) {
 990   Bytes::put_Java_u8(writeable_address(8), x);
 991 }
 992 
 993 void JvmtiClassFileReconstituter::copy_bytecodes(const methodHandle& mh,
 994                                                  unsigned char* bytecodes) {
 995   // use a BytecodeStream to iterate over the bytecodes. JVM/fast bytecodes
 996   // and the breakpoint bytecode are converted to their original bytecodes.
 997 
 998   BytecodeStream bs(mh);
 999 
1000   unsigned char* p = bytecodes;
1001   Bytecodes::Code code;
1002   bool is_rewritten = mh->method_holder()->is_rewritten();
1003 
1004   while ((code = bs.next()) >= 0) {
1005     assert(Bytecodes::is_java_code(code), "sanity check");
1006     assert(code != Bytecodes::_breakpoint, "sanity check");
1007 
1008     // length of bytecode (mnemonic + operands)
1009     address bcp = bs.bcp();
1010     int     len = bs.instruction_size();
1011     assert(len > 0, "length must be > 0");
1012 
1013     // copy the bytecodes
1014     *p = (unsigned char) (bs.is_wide()? Bytecodes::_wide : code);
1015     if (len > 1) {
1016       memcpy(p+1, bcp+1, len-1);
1017     }
1018 
1019     // During linking the get/put and invoke instructions are rewritten
1020     // with an index into the constant pool cache. The original constant
1021     // pool index must be returned to caller.  Rewrite the index.
1022     if (is_rewritten && len > 1) {
1023       bool is_wide = false;
1024       switch (code) {
1025       case Bytecodes::_getstatic       :  // fall through
1026       case Bytecodes::_putstatic       :  // fall through
1027       case Bytecodes::_getfield        :  // fall through
1028       case Bytecodes::_putfield        :  // fall through
1029       case Bytecodes::_withfield       :  // fall through
1030       case Bytecodes::_invokevirtual   :  // fall through
1031       case Bytecodes::_invokespecial   :  // fall through
1032       case Bytecodes::_invokestatic    :  // fall through
1033       case Bytecodes::_invokedynamic   :  // fall through
1034       case Bytecodes::_invokeinterface : {
1035         assert(len == 3 ||
1036                (code == Bytecodes::_invokeinterface && len == 5) ||
1037                (code == Bytecodes::_invokedynamic   && len == 5),
1038                "sanity check");
1039 
1040         int cpci = Bytes::get_native_u2(bcp+1);
1041         bool is_invokedynamic = (code == Bytecodes::_invokedynamic);
1042         ConstantPoolCacheEntry* entry;
1043         if (is_invokedynamic) {
1044           cpci = Bytes::get_native_u4(bcp+1);
1045           entry = mh->constants()->invokedynamic_cp_cache_entry_at(cpci);
1046         } else {
1047         // cache cannot be pre-fetched since some classes won't have it yet
1048           entry = mh->constants()->cache()->entry_at(cpci);
1049         }
1050         int i = entry->constant_pool_index();
1051         assert(i < mh->constants()->length(), "sanity check");
1052         Bytes::put_Java_u2((address)(p+1), (u2)i);     // java byte ordering
1053         if (is_invokedynamic)  *(p+3) = *(p+4) = 0;
1054         break;
1055       }
1056       case Bytecodes::_ldc_w:
1057         is_wide = true; // fall through
1058       case Bytecodes::_ldc: {
1059         if (bs.raw_code() == Bytecodes::_fast_aldc || bs.raw_code() == Bytecodes::_fast_aldc_w) {
1060           int cpci = is_wide ? Bytes::get_native_u2(bcp+1) : (u1)(*(bcp+1));
1061           int i = mh->constants()->object_to_cp_index(cpci);
1062           assert(i < mh->constants()->length(), "sanity check");
1063           if (is_wide) {
1064             Bytes::put_Java_u2((address)(p+1), (u2)i);     // java byte ordering
1065           } else {
1066             *(p+1) = (u1)i;
1067           }
1068         }
1069         break;
1070         }
1071       default:
1072         break;
1073       }
1074     }
1075 
1076     p += len;
1077   }
1078 }