1 /*
   2  * Copyright (c) 1998, 2013, 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/classFileStream.hpp"
  27 #include "classfile/javaClasses.hpp"
  28 #include "classfile/stackMapTable.hpp"
  29 #include "classfile/stackMapFrame.hpp"
  30 #include "classfile/stackMapTableFormat.hpp"
  31 #include "classfile/systemDictionary.hpp"
  32 #include "classfile/verifier.hpp"
  33 #include "classfile/vmSymbols.hpp"
  34 #include "interpreter/bytecodes.hpp"
  35 #include "interpreter/bytecodeStream.hpp"
  36 #include "memory/oopFactory.hpp"
  37 #include "memory/resourceArea.hpp"
  38 #include "oops/instanceKlass.hpp"
  39 #include "oops/oop.inline.hpp"
  40 #include "oops/typeArrayOop.hpp"
  41 #include "prims/jvm.h"
  42 #include "runtime/fieldDescriptor.hpp"
  43 #include "runtime/handles.inline.hpp"
  44 #include "runtime/interfaceSupport.hpp"
  45 #include "runtime/javaCalls.hpp"
  46 #include "runtime/orderAccess.hpp"
  47 #include "runtime/os.hpp"
  48 #ifdef TARGET_ARCH_x86
  49 # include "bytes_x86.hpp"
  50 #endif
  51 #ifdef TARGET_ARCH_sparc
  52 # include "bytes_sparc.hpp"
  53 #endif
  54 #ifdef TARGET_ARCH_zero
  55 # include "bytes_zero.hpp"
  56 #endif
  57 #ifdef TARGET_ARCH_arm
  58 # include "bytes_arm.hpp"
  59 #endif
  60 #ifdef TARGET_ARCH_ppc
  61 # include "bytes_ppc.hpp"
  62 #endif
  63 
  64 #define NOFAILOVER_MAJOR_VERSION                       51
  65 #define NONZERO_PADDING_BYTES_IN_SWITCH_MAJOR_VERSION  51
  66 #define STATIC_METHOD_IN_INTERFACE_MAJOR_VERSION       52
  67 
  68 // Access to external entry for VerifyClassCodes - old byte code verifier
  69 
  70 extern "C" {
  71   typedef jboolean (*verify_byte_codes_fn_t)(JNIEnv *, jclass, char *, jint);
  72   typedef jboolean (*verify_byte_codes_fn_new_t)(JNIEnv *, jclass, char *, jint, jint);
  73 }
  74 
  75 static void* volatile _verify_byte_codes_fn = NULL;
  76 
  77 static volatile jint _is_new_verify_byte_codes_fn = (jint) true;
  78 
  79 static void* verify_byte_codes_fn() {
  80   if (_verify_byte_codes_fn == NULL) {
  81     void *lib_handle = os::native_java_library();
  82     void *func = os::dll_lookup(lib_handle, "VerifyClassCodesForMajorVersion");
  83     OrderAccess::release_store_ptr(&_verify_byte_codes_fn, func);
  84     if (func == NULL) {
  85       OrderAccess::release_store(&_is_new_verify_byte_codes_fn, false);
  86       func = os::dll_lookup(lib_handle, "VerifyClassCodes");
  87       OrderAccess::release_store_ptr(&_verify_byte_codes_fn, func);
  88     }
  89   }
  90   return (void*)_verify_byte_codes_fn;
  91 }
  92 
  93 
  94 // Methods in Verifier
  95 
  96 bool Verifier::should_verify_for(oop class_loader, bool should_verify_class) {
  97   return (class_loader == NULL || !should_verify_class) ?
  98     BytecodeVerificationLocal : BytecodeVerificationRemote;
  99 }
 100 
 101 bool Verifier::relax_verify_for(oop loader) {
 102   bool trusted = java_lang_ClassLoader::is_trusted_loader(loader);
 103   bool need_verify =
 104     // verifyAll
 105     (BytecodeVerificationLocal && BytecodeVerificationRemote) ||
 106     // verifyRemote
 107     (!BytecodeVerificationLocal && BytecodeVerificationRemote && !trusted);
 108   return !need_verify;
 109 }
 110 
 111 bool Verifier::verify(instanceKlassHandle klass, Verifier::Mode mode, bool should_verify_class, TRAPS) {
 112   HandleMark hm;
 113   ResourceMark rm(THREAD);
 114 
 115   Symbol* exception_name = NULL;
 116   const size_t message_buffer_len = klass->name()->utf8_length() + 1024;
 117   char* message_buffer = NEW_RESOURCE_ARRAY(char, message_buffer_len);
 118   char* exception_message = message_buffer;
 119 
 120   const char* klassName = klass->external_name();
 121   bool can_failover = FailOverToOldVerifier &&
 122       klass->major_version() < NOFAILOVER_MAJOR_VERSION;
 123 
 124   // If the class should be verified, first see if we can use the split
 125   // verifier.  If not, or if verification fails and FailOverToOldVerifier
 126   // is set, then call the inference verifier.
 127   if (is_eligible_for_verification(klass, should_verify_class)) {
 128     if (TraceClassInitialization) {
 129       tty->print_cr("Start class verification for: %s", klassName);
 130     }
 131     if (klass->major_version() >= STACKMAP_ATTRIBUTE_MAJOR_VERSION) {
 132       ClassVerifier split_verifier(klass, THREAD);
 133       split_verifier.verify_class(THREAD);
 134       exception_name = split_verifier.result();
 135       if (can_failover && !HAS_PENDING_EXCEPTION &&
 136           (exception_name == vmSymbols::java_lang_VerifyError() ||
 137            exception_name == vmSymbols::java_lang_ClassFormatError())) {
 138         if (TraceClassInitialization || VerboseVerification) {
 139           tty->print_cr(
 140             "Fail over class verification to old verifier for: %s", klassName);
 141         }
 142         exception_name = inference_verify(
 143           klass, message_buffer, message_buffer_len, THREAD);
 144       }
 145       if (exception_name != NULL) {
 146         exception_message = split_verifier.exception_message();
 147       }
 148     } else {
 149       exception_name = inference_verify(
 150           klass, message_buffer, message_buffer_len, THREAD);
 151     }
 152 
 153     if (TraceClassInitialization || VerboseVerification) {
 154       if (HAS_PENDING_EXCEPTION) {
 155         tty->print("Verification for %s has", klassName);
 156         tty->print_cr(" exception pending %s ",
 157           InstanceKlass::cast(PENDING_EXCEPTION->klass())->external_name());
 158       } else if (exception_name != NULL) {
 159         tty->print_cr("Verification for %s failed", klassName);
 160       }
 161       tty->print_cr("End class verification for: %s", klassName);
 162     }
 163   }
 164 
 165   if (HAS_PENDING_EXCEPTION) {
 166     return false; // use the existing exception
 167   } else if (exception_name == NULL) {
 168     return true; // verifcation succeeded
 169   } else { // VerifyError or ClassFormatError to be created and thrown
 170     ResourceMark rm(THREAD);
 171     instanceKlassHandle kls =
 172       SystemDictionary::resolve_or_fail(exception_name, true, CHECK_false);
 173     while (!kls.is_null()) {
 174       if (kls == klass) {
 175         // If the class being verified is the exception we're creating
 176         // or one of it's superclasses, we're in trouble and are going
 177         // to infinitely recurse when we try to initialize the exception.
 178         // So bail out here by throwing the preallocated VM error.
 179         THROW_OOP_(Universe::virtual_machine_error_instance(), false);
 180       }
 181       kls = kls->super();
 182     }
 183     message_buffer[message_buffer_len - 1] = '\0'; // just to be sure
 184     THROW_MSG_(exception_name, exception_message, false);
 185   }
 186 }
 187 
 188 bool Verifier::is_eligible_for_verification(instanceKlassHandle klass, bool should_verify_class) {
 189   Symbol* name = klass->name();
 190   Klass* refl_magic_klass = SystemDictionary::reflect_MagicAccessorImpl_klass();
 191 
 192   bool is_reflect = refl_magic_klass != NULL && klass->is_subtype_of(refl_magic_klass);
 193 
 194   return (should_verify_for(klass->class_loader(), should_verify_class) &&
 195     // return if the class is a bootstrapping class
 196     // or defineClass specified not to verify by default (flags override passed arg)
 197     // We need to skip the following four for bootstraping
 198     name != vmSymbols::java_lang_Object() &&
 199     name != vmSymbols::java_lang_Class() &&
 200     name != vmSymbols::java_lang_String() &&
 201     name != vmSymbols::java_lang_Throwable() &&
 202 
 203     // Can not verify the bytecodes for shared classes because they have
 204     // already been rewritten to contain constant pool cache indices,
 205     // which the verifier can't understand.
 206     // Shared classes shouldn't have stackmaps either.
 207     !klass()->is_shared() &&
 208 
 209     // As of the fix for 4486457 we disable verification for all of the
 210     // dynamically-generated bytecodes associated with the 1.4
 211     // reflection implementation, not just those associated with
 212     // sun/reflect/SerializationConstructorAccessor.
 213     // NOTE: this is called too early in the bootstrapping process to be
 214     // guarded by Universe::is_gte_jdk14x_version()/UseNewReflection.
 215     // Also for lambda generated code, gte jdk8
 216     (!is_reflect || VerifyReflectionBytecodes));
 217 }
 218 
 219 Symbol* Verifier::inference_verify(
 220     instanceKlassHandle klass, char* message, size_t message_len, TRAPS) {
 221   JavaThread* thread = (JavaThread*)THREAD;
 222   JNIEnv *env = thread->jni_environment();
 223 
 224   void* verify_func = verify_byte_codes_fn();
 225 
 226   if (verify_func == NULL) {
 227     jio_snprintf(message, message_len, "Could not link verifier");
 228     return vmSymbols::java_lang_VerifyError();
 229   }
 230 
 231   ResourceMark rm(THREAD);
 232   if (VerboseVerification) {
 233     tty->print_cr("Verifying class %s with old format", klass->external_name());
 234   }
 235 
 236   jclass cls = (jclass) JNIHandles::make_local(env, klass->java_mirror());
 237   jint result;
 238 
 239   {
 240     HandleMark hm(thread);
 241     ThreadToNativeFromVM ttn(thread);
 242     // ThreadToNativeFromVM takes care of changing thread_state, so safepoint
 243     // code knows that we have left the VM
 244 
 245     if (_is_new_verify_byte_codes_fn) {
 246       verify_byte_codes_fn_new_t func =
 247         CAST_TO_FN_PTR(verify_byte_codes_fn_new_t, verify_func);
 248       result = (*func)(env, cls, message, (int)message_len,
 249           klass->major_version());
 250     } else {
 251       verify_byte_codes_fn_t func =
 252         CAST_TO_FN_PTR(verify_byte_codes_fn_t, verify_func);
 253       result = (*func)(env, cls, message, (int)message_len);
 254     }
 255   }
 256 
 257   JNIHandles::destroy_local(cls);
 258 
 259   // These numbers are chosen so that VerifyClassCodes interface doesn't need
 260   // to be changed (still return jboolean (unsigned char)), and result is
 261   // 1 when verification is passed.
 262   if (result == 0) {
 263     return vmSymbols::java_lang_VerifyError();
 264   } else if (result == 1) {
 265     return NULL; // verified.
 266   } else if (result == 2) {
 267     THROW_MSG_(vmSymbols::java_lang_OutOfMemoryError(), message, NULL);
 268   } else if (result == 3) {
 269     return vmSymbols::java_lang_ClassFormatError();
 270   } else {
 271     ShouldNotReachHere();
 272     return NULL;
 273   }
 274 }
 275 
 276 TypeOrigin TypeOrigin::null() {
 277   return TypeOrigin();
 278 }
 279 TypeOrigin TypeOrigin::local(u2 index, StackMapFrame* frame) {
 280   assert(frame != NULL, "Must have a frame");
 281   return TypeOrigin(CF_LOCALS, index, StackMapFrame::copy(frame),
 282      frame->local_at(index));
 283 }
 284 TypeOrigin TypeOrigin::stack(u2 index, StackMapFrame* frame) {
 285   assert(frame != NULL, "Must have a frame");
 286   return TypeOrigin(CF_STACK, index, StackMapFrame::copy(frame),
 287       frame->stack_at(index));
 288 }
 289 TypeOrigin TypeOrigin::sm_local(u2 index, StackMapFrame* frame) {
 290   assert(frame != NULL, "Must have a frame");
 291   return TypeOrigin(SM_LOCALS, index, StackMapFrame::copy(frame),
 292       frame->local_at(index));
 293 }
 294 TypeOrigin TypeOrigin::sm_stack(u2 index, StackMapFrame* frame) {
 295   assert(frame != NULL, "Must have a frame");
 296   return TypeOrigin(SM_STACK, index, StackMapFrame::copy(frame),
 297       frame->stack_at(index));
 298 }
 299 TypeOrigin TypeOrigin::bad_index(u2 index) {
 300   return TypeOrigin(BAD_INDEX, index, NULL, VerificationType::bogus_type());
 301 }
 302 TypeOrigin TypeOrigin::cp(u2 index, VerificationType vt) {
 303   return TypeOrigin(CONST_POOL, index, NULL, vt);
 304 }
 305 TypeOrigin TypeOrigin::signature(VerificationType vt) {
 306   return TypeOrigin(SIG, 0, NULL, vt);
 307 }
 308 TypeOrigin TypeOrigin::implicit(VerificationType t) {
 309   return TypeOrigin(IMPLICIT, 0, NULL, t);
 310 }
 311 TypeOrigin TypeOrigin::frame(StackMapFrame* frame) {
 312   return TypeOrigin(FRAME_ONLY, 0, StackMapFrame::copy(frame),
 313                     VerificationType::bogus_type());
 314 }
 315 
 316 void TypeOrigin::reset_frame() {
 317   if (_frame != NULL) {
 318     _frame->restore();
 319   }
 320 }
 321 
 322 void TypeOrigin::details(outputStream* ss) const {
 323   _type.print_on(ss);
 324   switch (_origin) {
 325     case CF_LOCALS:
 326       ss->print(" (current frame, locals[%d])", _index);
 327       break;
 328     case CF_STACK:
 329       ss->print(" (current frame, stack[%d])", _index);
 330       break;
 331     case SM_LOCALS:
 332       ss->print(" (stack map, locals[%d])", _index);
 333       break;
 334     case SM_STACK:
 335       ss->print(" (stack map, stack[%d])", _index);
 336       break;
 337     case CONST_POOL:
 338       ss->print(" (constant pool %d)", _index);
 339       break;
 340     case SIG:
 341       ss->print(" (from method signature)");
 342       break;
 343     case IMPLICIT:
 344     case FRAME_ONLY:
 345     case NONE:
 346     default:
 347       ;
 348   }
 349 }
 350 
 351 #ifdef ASSERT
 352 void TypeOrigin::print_on(outputStream* str) const {
 353   str->print("{%d,%d,%p:", _origin, _index, _frame);
 354   if (_frame != NULL) {
 355     _frame->print_on(str);
 356   } else {
 357     str->print("null");
 358   }
 359   str->print(",");
 360   _type.print_on(str);
 361   str->print("}");
 362 }
 363 #endif
 364 
 365 void ErrorContext::details(outputStream* ss, const Method* method) const {
 366   if (is_valid()) {
 367     ss->print_cr("");
 368     ss->print_cr("Exception Details:");
 369     location_details(ss, method);
 370     reason_details(ss);
 371     frame_details(ss);
 372     bytecode_details(ss, method);
 373     handler_details(ss, method);
 374     stackmap_details(ss, method);
 375   }
 376 }
 377 
 378 void ErrorContext::reason_details(outputStream* ss) const {
 379   streamIndentor si(ss);
 380   ss->indent().print_cr("Reason:");
 381   streamIndentor si2(ss);
 382   ss->indent().print("");
 383   switch (_fault) {
 384     case INVALID_BYTECODE:
 385       ss->print("Error exists in the bytecode");
 386       break;
 387     case WRONG_TYPE:
 388       if (_expected.is_valid()) {
 389         ss->print("Type ");
 390         _type.details(ss);
 391         ss->print(" is not assignable to ");
 392         _expected.details(ss);
 393       } else {
 394         ss->print("Invalid type: ");
 395         _type.details(ss);
 396       }
 397       break;
 398     case FLAGS_MISMATCH:
 399       if (_expected.is_valid()) {
 400         ss->print("Current frame's flags are not assignable "
 401                   "to stack map frame's.");
 402       } else {
 403         ss->print("Current frame's flags are invalid in this context.");
 404       }
 405       break;
 406     case BAD_CP_INDEX:
 407       ss->print("Constant pool index %d is invalid", _type.index());
 408       break;
 409     case BAD_LOCAL_INDEX:
 410       ss->print("Local index %d is invalid", _type.index());
 411       break;
 412     case LOCALS_SIZE_MISMATCH:
 413       ss->print("Current frame's local size doesn't match stackmap.");
 414       break;
 415     case STACK_SIZE_MISMATCH:
 416       ss->print("Current frame's stack size doesn't match stackmap.");
 417       break;
 418     case STACK_OVERFLOW:
 419       ss->print("Exceeded max stack size.");
 420       break;
 421     case STACK_UNDERFLOW:
 422       ss->print("Attempt to pop empty stack.");
 423       break;
 424     case MISSING_STACKMAP:
 425       ss->print("Expected stackmap frame at this location.");
 426       break;
 427     case BAD_STACKMAP:
 428       ss->print("Invalid stackmap specification.");
 429       break;
 430     case UNKNOWN:
 431     default:
 432       ShouldNotReachHere();
 433       ss->print_cr("Unknown");
 434   }
 435   ss->print_cr("");
 436 }
 437 
 438 void ErrorContext::location_details(outputStream* ss, const Method* method) const {
 439   if (_bci != -1 && method != NULL) {
 440     streamIndentor si(ss);
 441     const char* bytecode_name = "<invalid>";
 442     if (method->validate_bci_from_bcx(_bci) != -1) {
 443       Bytecodes::Code code = Bytecodes::code_or_bp_at(method->bcp_from(_bci));
 444       if (Bytecodes::is_defined(code)) {
 445           bytecode_name = Bytecodes::name(code);
 446       } else {
 447           bytecode_name = "<illegal>";
 448       }
 449     }
 450     InstanceKlass* ik = method->method_holder();
 451     ss->indent().print_cr("Location:");
 452     streamIndentor si2(ss);
 453     ss->indent().print_cr("%s.%s%s @%d: %s",
 454         ik->name()->as_C_string(), method->name()->as_C_string(),
 455         method->signature()->as_C_string(), _bci, bytecode_name);
 456   }
 457 }
 458 
 459 void ErrorContext::frame_details(outputStream* ss) const {
 460   streamIndentor si(ss);
 461   if (_type.is_valid() && _type.frame() != NULL) {
 462     ss->indent().print_cr("Current Frame:");
 463     streamIndentor si2(ss);
 464     _type.frame()->print_on(ss);
 465   }
 466   if (_expected.is_valid() && _expected.frame() != NULL) {
 467     ss->indent().print_cr("Stackmap Frame:");
 468     streamIndentor si2(ss);
 469     _expected.frame()->print_on(ss);
 470   }
 471 }
 472 
 473 void ErrorContext::bytecode_details(outputStream* ss, const Method* method) const {
 474   if (method != NULL) {
 475     streamIndentor si(ss);
 476     ss->indent().print_cr("Bytecode:");
 477     streamIndentor si2(ss);
 478     ss->print_data(method->code_base(), method->code_size(), false);
 479   }
 480 }
 481 
 482 void ErrorContext::handler_details(outputStream* ss, const Method* method) const {
 483   if (method != NULL) {
 484     streamIndentor si(ss);
 485     ExceptionTable table(method);
 486     if (table.length() > 0) {
 487       ss->indent().print_cr("Exception Handler Table:");
 488       streamIndentor si2(ss);
 489       for (int i = 0; i < table.length(); ++i) {
 490         ss->indent().print_cr("bci [%d, %d] => handler: %d", table.start_pc(i),
 491             table.end_pc(i), table.handler_pc(i));
 492       }
 493     }
 494   }
 495 }
 496 
 497 void ErrorContext::stackmap_details(outputStream* ss, const Method* method) const {
 498   if (method != NULL && method->has_stackmap_table()) {
 499     streamIndentor si(ss);
 500     ss->indent().print_cr("Stackmap Table:");
 501     Array<u1>* data = method->stackmap_data();
 502     stack_map_table* sm_table =
 503         stack_map_table::at((address)data->adr_at(0));
 504     stack_map_frame* sm_frame = sm_table->entries();
 505     streamIndentor si2(ss);
 506     int current_offset = -1;
 507     for (u2 i = 0; i < sm_table->number_of_entries(); ++i) {
 508       ss->indent();
 509       sm_frame->print_on(ss, current_offset);
 510       ss->print_cr("");
 511       current_offset += sm_frame->offset_delta();
 512       sm_frame = sm_frame->next();
 513     }
 514   }
 515 }
 516 
 517 // Methods in ClassVerifier
 518 
 519 ClassVerifier::ClassVerifier(
 520     instanceKlassHandle klass, TRAPS)
 521     : _thread(THREAD), _exception_type(NULL), _message(NULL), _klass(klass) {
 522   _this_type = VerificationType::reference_type(klass->name());
 523   // Create list to hold symbols in reference area.
 524   _symbols = new GrowableArray<Symbol*>(100, 0, NULL);
 525 }
 526 
 527 ClassVerifier::~ClassVerifier() {
 528   // Decrement the reference count for any symbols created.
 529   for (int i = 0; i < _symbols->length(); i++) {
 530     Symbol* s = _symbols->at(i);
 531     s->decrement_refcount();
 532   }
 533 }
 534 
 535 VerificationType ClassVerifier::object_type() const {
 536   return VerificationType::reference_type(vmSymbols::java_lang_Object());
 537 }
 538 
 539 TypeOrigin ClassVerifier::ref_ctx(const char* sig, TRAPS) {
 540   VerificationType vt = VerificationType::reference_type(
 541       create_temporary_symbol(sig, (int)strlen(sig), THREAD));
 542   return TypeOrigin::implicit(vt);
 543 }
 544 
 545 void ClassVerifier::verify_class(TRAPS) {
 546   if (VerboseVerification) {
 547     tty->print_cr("Verifying class %s with new format",
 548       _klass->external_name());
 549   }
 550 
 551   Array<Method*>* methods = _klass->methods();
 552   int num_methods = methods->length();
 553 
 554   for (int index = 0; index < num_methods; index++) {
 555     // Check for recursive re-verification before each method.
 556     if (was_recursively_verified())  return;
 557 
 558     Method* m = methods->at(index);
 559     if (m->is_native() || m->is_abstract() || m->is_overpass()) {
 560       // If m is native or abstract, skip it.  It is checked in class file
 561       // parser that methods do not override a final method.  Overpass methods
 562       // are trusted since the VM generates them.
 563       continue;
 564     }
 565     verify_method(methodHandle(THREAD, m), CHECK_VERIFY(this));
 566   }
 567 
 568   if (VerboseVerification || TraceClassInitialization) {
 569     if (was_recursively_verified())
 570       tty->print_cr("Recursive verification detected for: %s",
 571           _klass->external_name());
 572   }
 573 }
 574 
 575 void ClassVerifier::verify_method(methodHandle m, TRAPS) {
 576   HandleMark hm(THREAD);
 577   _method = m;   // initialize _method
 578   if (VerboseVerification) {
 579     tty->print_cr("Verifying method %s", m->name_and_sig_as_C_string());
 580   }
 581 
 582   const char* bad_type_msg = "Bad type on operand stack in %s";
 583 
 584   int32_t max_stack = m->verifier_max_stack();
 585   int32_t max_locals = m->max_locals();
 586   constantPoolHandle cp(THREAD, m->constants());
 587 
 588   if (!SignatureVerifier::is_valid_method_signature(m->signature())) {
 589     class_format_error("Invalid method signature");
 590     return;
 591   }
 592 
 593   // Initial stack map frame: offset is 0, stack is initially empty.
 594   StackMapFrame current_frame(max_locals, max_stack, this);
 595   // Set initial locals
 596   VerificationType return_type = current_frame.set_locals_from_arg(
 597     m, current_type(), CHECK_VERIFY(this));
 598 
 599   int32_t stackmap_index = 0; // index to the stackmap array
 600 
 601   u4 code_length = m->code_size();
 602 
 603   // Scan the bytecode and map each instruction's start offset to a number.
 604   char* code_data = generate_code_data(m, code_length, CHECK_VERIFY(this));
 605 
 606   int ex_min = code_length;
 607   int ex_max = -1;
 608   // Look through each item on the exception table. Each of the fields must refer
 609   // to a legal instruction.
 610   verify_exception_handler_table(
 611     code_length, code_data, ex_min, ex_max, CHECK_VERIFY(this));
 612 
 613   // Look through each entry on the local variable table and make sure
 614   // its range of code array offsets is valid. (4169817)
 615   if (m->has_localvariable_table()) {
 616     verify_local_variable_table(code_length, code_data, CHECK_VERIFY(this));
 617   }
 618 
 619   Array<u1>* stackmap_data = m->stackmap_data();
 620   StackMapStream stream(stackmap_data);
 621   StackMapReader reader(this, &stream, code_data, code_length, THREAD);
 622   StackMapTable stackmap_table(&reader, &current_frame, max_locals, max_stack,
 623                                code_data, code_length, CHECK_VERIFY(this));
 624 
 625   if (VerboseVerification) {
 626     stackmap_table.print_on(tty);
 627   }
 628 
 629   RawBytecodeStream bcs(m);
 630 
 631   // Scan the byte code linearly from the start to the end
 632   bool no_control_flow = false; // Set to true when there is no direct control
 633                                 // flow from current instruction to the next
 634                                 // instruction in sequence
 635   Bytecodes::Code opcode;
 636   while (!bcs.is_last_bytecode()) {
 637     // Check for recursive re-verification before each bytecode.
 638     if (was_recursively_verified())  return;
 639 
 640     opcode = bcs.raw_next();
 641     u2 bci = bcs.bci();
 642 
 643     // Set current frame's offset to bci
 644     current_frame.set_offset(bci);
 645     current_frame.set_mark();
 646 
 647     // Make sure every offset in stackmap table point to the beginning to
 648     // an instruction. Match current_frame to stackmap_table entry with
 649     // the same offset if exists.
 650     stackmap_index = verify_stackmap_table(
 651       stackmap_index, bci, &current_frame, &stackmap_table,
 652       no_control_flow, CHECK_VERIFY(this));
 653 
 654 
 655     bool this_uninit = false;  // Set to true when invokespecial <init> initialized 'this'
 656 
 657     // Merge with the next instruction
 658     {
 659       u2 index;
 660       int target;
 661       VerificationType type, type2;
 662       VerificationType atype;
 663 
 664 #ifndef PRODUCT
 665       if (VerboseVerification) {
 666         current_frame.print_on(tty);
 667         tty->print_cr("offset = %d,  opcode = %s", bci, Bytecodes::name(opcode));
 668       }
 669 #endif
 670 
 671       // Make sure wide instruction is in correct format
 672       if (bcs.is_wide()) {
 673         if (opcode != Bytecodes::_iinc   && opcode != Bytecodes::_iload  &&
 674             opcode != Bytecodes::_aload  && opcode != Bytecodes::_lload  &&
 675             opcode != Bytecodes::_istore && opcode != Bytecodes::_astore &&
 676             opcode != Bytecodes::_lstore && opcode != Bytecodes::_fload  &&
 677             opcode != Bytecodes::_dload  && opcode != Bytecodes::_fstore &&
 678             opcode != Bytecodes::_dstore) {
 679           /* Unreachable?  RawBytecodeStream's raw_next() returns 'illegal'
 680            * if we encounter a wide instruction that modifies an invalid
 681            * opcode (not one of the ones listed above) */
 682           verify_error(ErrorContext::bad_code(bci), "Bad wide instruction");
 683           return;
 684         }
 685       }
 686 
 687       switch (opcode) {
 688         case Bytecodes::_nop :
 689           no_control_flow = false; break;
 690         case Bytecodes::_aconst_null :
 691           current_frame.push_stack(
 692             VerificationType::null_type(), CHECK_VERIFY(this));
 693           no_control_flow = false; break;
 694         case Bytecodes::_iconst_m1 :
 695         case Bytecodes::_iconst_0 :
 696         case Bytecodes::_iconst_1 :
 697         case Bytecodes::_iconst_2 :
 698         case Bytecodes::_iconst_3 :
 699         case Bytecodes::_iconst_4 :
 700         case Bytecodes::_iconst_5 :
 701           current_frame.push_stack(
 702             VerificationType::integer_type(), CHECK_VERIFY(this));
 703           no_control_flow = false; break;
 704         case Bytecodes::_lconst_0 :
 705         case Bytecodes::_lconst_1 :
 706           current_frame.push_stack_2(
 707             VerificationType::long_type(),
 708             VerificationType::long2_type(), CHECK_VERIFY(this));
 709           no_control_flow = false; break;
 710         case Bytecodes::_fconst_0 :
 711         case Bytecodes::_fconst_1 :
 712         case Bytecodes::_fconst_2 :
 713           current_frame.push_stack(
 714             VerificationType::float_type(), CHECK_VERIFY(this));
 715           no_control_flow = false; break;
 716         case Bytecodes::_dconst_0 :
 717         case Bytecodes::_dconst_1 :
 718           current_frame.push_stack_2(
 719             VerificationType::double_type(),
 720             VerificationType::double2_type(), CHECK_VERIFY(this));
 721           no_control_flow = false; break;
 722         case Bytecodes::_sipush :
 723         case Bytecodes::_bipush :
 724           current_frame.push_stack(
 725             VerificationType::integer_type(), CHECK_VERIFY(this));
 726           no_control_flow = false; break;
 727         case Bytecodes::_ldc :
 728           verify_ldc(
 729             opcode, bcs.get_index_u1(), &current_frame,
 730             cp, bci, CHECK_VERIFY(this));
 731           no_control_flow = false; break;
 732         case Bytecodes::_ldc_w :
 733         case Bytecodes::_ldc2_w :
 734           verify_ldc(
 735             opcode, bcs.get_index_u2(), &current_frame,
 736             cp, bci, CHECK_VERIFY(this));
 737           no_control_flow = false; break;
 738         case Bytecodes::_iload :
 739           verify_iload(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
 740           no_control_flow = false; break;
 741         case Bytecodes::_iload_0 :
 742         case Bytecodes::_iload_1 :
 743         case Bytecodes::_iload_2 :
 744         case Bytecodes::_iload_3 :
 745           index = opcode - Bytecodes::_iload_0;
 746           verify_iload(index, &current_frame, CHECK_VERIFY(this));
 747           no_control_flow = false; break;
 748         case Bytecodes::_lload :
 749           verify_lload(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
 750           no_control_flow = false; break;
 751         case Bytecodes::_lload_0 :
 752         case Bytecodes::_lload_1 :
 753         case Bytecodes::_lload_2 :
 754         case Bytecodes::_lload_3 :
 755           index = opcode - Bytecodes::_lload_0;
 756           verify_lload(index, &current_frame, CHECK_VERIFY(this));
 757           no_control_flow = false; break;
 758         case Bytecodes::_fload :
 759           verify_fload(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
 760           no_control_flow = false; break;
 761         case Bytecodes::_fload_0 :
 762         case Bytecodes::_fload_1 :
 763         case Bytecodes::_fload_2 :
 764         case Bytecodes::_fload_3 :
 765           index = opcode - Bytecodes::_fload_0;
 766           verify_fload(index, &current_frame, CHECK_VERIFY(this));
 767           no_control_flow = false; break;
 768         case Bytecodes::_dload :
 769           verify_dload(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
 770           no_control_flow = false; break;
 771         case Bytecodes::_dload_0 :
 772         case Bytecodes::_dload_1 :
 773         case Bytecodes::_dload_2 :
 774         case Bytecodes::_dload_3 :
 775           index = opcode - Bytecodes::_dload_0;
 776           verify_dload(index, &current_frame, CHECK_VERIFY(this));
 777           no_control_flow = false; break;
 778         case Bytecodes::_aload :
 779           verify_aload(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
 780           no_control_flow = false; break;
 781         case Bytecodes::_aload_0 :
 782         case Bytecodes::_aload_1 :
 783         case Bytecodes::_aload_2 :
 784         case Bytecodes::_aload_3 :
 785           index = opcode - Bytecodes::_aload_0;
 786           verify_aload(index, &current_frame, CHECK_VERIFY(this));
 787           no_control_flow = false; break;
 788         case Bytecodes::_iaload :
 789           type = current_frame.pop_stack(
 790             VerificationType::integer_type(), CHECK_VERIFY(this));
 791           atype = current_frame.pop_stack(
 792             VerificationType::reference_check(), CHECK_VERIFY(this));
 793           if (!atype.is_int_array()) {
 794             verify_error(ErrorContext::bad_type(bci,
 795                 current_frame.stack_top_ctx(), ref_ctx("[I", THREAD)),
 796                 bad_type_msg, "iaload");
 797             return;
 798           }
 799           current_frame.push_stack(
 800             VerificationType::integer_type(), CHECK_VERIFY(this));
 801           no_control_flow = false; break;
 802         case Bytecodes::_baload :
 803           type = current_frame.pop_stack(
 804             VerificationType::integer_type(), CHECK_VERIFY(this));
 805           atype = current_frame.pop_stack(
 806             VerificationType::reference_check(), CHECK_VERIFY(this));
 807           if (!atype.is_bool_array() && !atype.is_byte_array()) {
 808             verify_error(
 809                 ErrorContext::bad_type(bci, current_frame.stack_top_ctx()),
 810                 bad_type_msg, "baload");
 811             return;
 812           }
 813           current_frame.push_stack(
 814             VerificationType::integer_type(), CHECK_VERIFY(this));
 815           no_control_flow = false; break;
 816         case Bytecodes::_caload :
 817           type = current_frame.pop_stack(
 818             VerificationType::integer_type(), CHECK_VERIFY(this));
 819           atype = current_frame.pop_stack(
 820             VerificationType::reference_check(), CHECK_VERIFY(this));
 821           if (!atype.is_char_array()) {
 822             verify_error(ErrorContext::bad_type(bci,
 823                 current_frame.stack_top_ctx(), ref_ctx("[C", THREAD)),
 824                 bad_type_msg, "caload");
 825             return;
 826           }
 827           current_frame.push_stack(
 828             VerificationType::integer_type(), CHECK_VERIFY(this));
 829           no_control_flow = false; break;
 830         case Bytecodes::_saload :
 831           type = current_frame.pop_stack(
 832             VerificationType::integer_type(), CHECK_VERIFY(this));
 833           atype = current_frame.pop_stack(
 834             VerificationType::reference_check(), CHECK_VERIFY(this));
 835           if (!atype.is_short_array()) {
 836             verify_error(ErrorContext::bad_type(bci,
 837                 current_frame.stack_top_ctx(), ref_ctx("[S", THREAD)),
 838                 bad_type_msg, "saload");
 839             return;
 840           }
 841           current_frame.push_stack(
 842             VerificationType::integer_type(), CHECK_VERIFY(this));
 843           no_control_flow = false; break;
 844         case Bytecodes::_laload :
 845           type = current_frame.pop_stack(
 846             VerificationType::integer_type(), CHECK_VERIFY(this));
 847           atype = current_frame.pop_stack(
 848             VerificationType::reference_check(), CHECK_VERIFY(this));
 849           if (!atype.is_long_array()) {
 850             verify_error(ErrorContext::bad_type(bci,
 851                 current_frame.stack_top_ctx(), ref_ctx("[J", THREAD)),
 852                 bad_type_msg, "laload");
 853             return;
 854           }
 855           current_frame.push_stack_2(
 856             VerificationType::long_type(),
 857             VerificationType::long2_type(), CHECK_VERIFY(this));
 858           no_control_flow = false; break;
 859         case Bytecodes::_faload :
 860           type = current_frame.pop_stack(
 861             VerificationType::integer_type(), CHECK_VERIFY(this));
 862           atype = current_frame.pop_stack(
 863             VerificationType::reference_check(), CHECK_VERIFY(this));
 864           if (!atype.is_float_array()) {
 865             verify_error(ErrorContext::bad_type(bci,
 866                 current_frame.stack_top_ctx(), ref_ctx("[F", THREAD)),
 867                 bad_type_msg, "faload");
 868             return;
 869           }
 870           current_frame.push_stack(
 871             VerificationType::float_type(), CHECK_VERIFY(this));
 872           no_control_flow = false; break;
 873         case Bytecodes::_daload :
 874           type = current_frame.pop_stack(
 875             VerificationType::integer_type(), CHECK_VERIFY(this));
 876           atype = current_frame.pop_stack(
 877             VerificationType::reference_check(), CHECK_VERIFY(this));
 878           if (!atype.is_double_array()) {
 879             verify_error(ErrorContext::bad_type(bci,
 880                 current_frame.stack_top_ctx(), ref_ctx("[D", THREAD)),
 881                 bad_type_msg, "daload");
 882             return;
 883           }
 884           current_frame.push_stack_2(
 885             VerificationType::double_type(),
 886             VerificationType::double2_type(), CHECK_VERIFY(this));
 887           no_control_flow = false; break;
 888         case Bytecodes::_aaload : {
 889           type = current_frame.pop_stack(
 890             VerificationType::integer_type(), CHECK_VERIFY(this));
 891           atype = current_frame.pop_stack(
 892             VerificationType::reference_check(), CHECK_VERIFY(this));
 893           if (!atype.is_reference_array()) {
 894             verify_error(ErrorContext::bad_type(bci,
 895                 current_frame.stack_top_ctx(),
 896                 TypeOrigin::implicit(VerificationType::reference_check())),
 897                 bad_type_msg, "aaload");
 898             return;
 899           }
 900           if (atype.is_null()) {
 901             current_frame.push_stack(
 902               VerificationType::null_type(), CHECK_VERIFY(this));
 903           } else {
 904             VerificationType component =
 905               atype.get_component(this, CHECK_VERIFY(this));
 906             current_frame.push_stack(component, CHECK_VERIFY(this));
 907           }
 908           no_control_flow = false; break;
 909         }
 910         case Bytecodes::_istore :
 911           verify_istore(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
 912           no_control_flow = false; break;
 913         case Bytecodes::_istore_0 :
 914         case Bytecodes::_istore_1 :
 915         case Bytecodes::_istore_2 :
 916         case Bytecodes::_istore_3 :
 917           index = opcode - Bytecodes::_istore_0;
 918           verify_istore(index, &current_frame, CHECK_VERIFY(this));
 919           no_control_flow = false; break;
 920         case Bytecodes::_lstore :
 921           verify_lstore(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
 922           no_control_flow = false; break;
 923         case Bytecodes::_lstore_0 :
 924         case Bytecodes::_lstore_1 :
 925         case Bytecodes::_lstore_2 :
 926         case Bytecodes::_lstore_3 :
 927           index = opcode - Bytecodes::_lstore_0;
 928           verify_lstore(index, &current_frame, CHECK_VERIFY(this));
 929           no_control_flow = false; break;
 930         case Bytecodes::_fstore :
 931           verify_fstore(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
 932           no_control_flow = false; break;
 933         case Bytecodes::_fstore_0 :
 934         case Bytecodes::_fstore_1 :
 935         case Bytecodes::_fstore_2 :
 936         case Bytecodes::_fstore_3 :
 937           index = opcode - Bytecodes::_fstore_0;
 938           verify_fstore(index, &current_frame, CHECK_VERIFY(this));
 939           no_control_flow = false; break;
 940         case Bytecodes::_dstore :
 941           verify_dstore(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
 942           no_control_flow = false; break;
 943         case Bytecodes::_dstore_0 :
 944         case Bytecodes::_dstore_1 :
 945         case Bytecodes::_dstore_2 :
 946         case Bytecodes::_dstore_3 :
 947           index = opcode - Bytecodes::_dstore_0;
 948           verify_dstore(index, &current_frame, CHECK_VERIFY(this));
 949           no_control_flow = false; break;
 950         case Bytecodes::_astore :
 951           verify_astore(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
 952           no_control_flow = false; break;
 953         case Bytecodes::_astore_0 :
 954         case Bytecodes::_astore_1 :
 955         case Bytecodes::_astore_2 :
 956         case Bytecodes::_astore_3 :
 957           index = opcode - Bytecodes::_astore_0;
 958           verify_astore(index, &current_frame, CHECK_VERIFY(this));
 959           no_control_flow = false; break;
 960         case Bytecodes::_iastore :
 961           type = current_frame.pop_stack(
 962             VerificationType::integer_type(), CHECK_VERIFY(this));
 963           type2 = current_frame.pop_stack(
 964             VerificationType::integer_type(), CHECK_VERIFY(this));
 965           atype = current_frame.pop_stack(
 966             VerificationType::reference_check(), CHECK_VERIFY(this));
 967           if (!atype.is_int_array()) {
 968             verify_error(ErrorContext::bad_type(bci,
 969                 current_frame.stack_top_ctx(), ref_ctx("[I", THREAD)),
 970                 bad_type_msg, "iastore");
 971             return;
 972           }
 973           no_control_flow = false; break;
 974         case Bytecodes::_bastore :
 975           type = current_frame.pop_stack(
 976             VerificationType::integer_type(), CHECK_VERIFY(this));
 977           type2 = current_frame.pop_stack(
 978             VerificationType::integer_type(), CHECK_VERIFY(this));
 979           atype = current_frame.pop_stack(
 980             VerificationType::reference_check(), CHECK_VERIFY(this));
 981           if (!atype.is_bool_array() && !atype.is_byte_array()) {
 982             verify_error(
 983                 ErrorContext::bad_type(bci, current_frame.stack_top_ctx()),
 984                 bad_type_msg, "bastore");
 985             return;
 986           }
 987           no_control_flow = false; break;
 988         case Bytecodes::_castore :
 989           current_frame.pop_stack(
 990             VerificationType::integer_type(), CHECK_VERIFY(this));
 991           current_frame.pop_stack(
 992             VerificationType::integer_type(), CHECK_VERIFY(this));
 993           atype = current_frame.pop_stack(
 994             VerificationType::reference_check(), CHECK_VERIFY(this));
 995           if (!atype.is_char_array()) {
 996             verify_error(ErrorContext::bad_type(bci,
 997                 current_frame.stack_top_ctx(), ref_ctx("[C", THREAD)),
 998                 bad_type_msg, "castore");
 999             return;
1000           }
1001           no_control_flow = false; break;
1002         case Bytecodes::_sastore :
1003           current_frame.pop_stack(
1004             VerificationType::integer_type(), CHECK_VERIFY(this));
1005           current_frame.pop_stack(
1006             VerificationType::integer_type(), CHECK_VERIFY(this));
1007           atype = current_frame.pop_stack(
1008             VerificationType::reference_check(), CHECK_VERIFY(this));
1009           if (!atype.is_short_array()) {
1010             verify_error(ErrorContext::bad_type(bci,
1011                 current_frame.stack_top_ctx(), ref_ctx("[S", THREAD)),
1012                 bad_type_msg, "sastore");
1013             return;
1014           }
1015           no_control_flow = false; break;
1016         case Bytecodes::_lastore :
1017           current_frame.pop_stack_2(
1018             VerificationType::long2_type(),
1019             VerificationType::long_type(), CHECK_VERIFY(this));
1020           current_frame.pop_stack(
1021             VerificationType::integer_type(), CHECK_VERIFY(this));
1022           atype = current_frame.pop_stack(
1023             VerificationType::reference_check(), CHECK_VERIFY(this));
1024           if (!atype.is_long_array()) {
1025             verify_error(ErrorContext::bad_type(bci,
1026                 current_frame.stack_top_ctx(), ref_ctx("[J", THREAD)),
1027                 bad_type_msg, "lastore");
1028             return;
1029           }
1030           no_control_flow = false; break;
1031         case Bytecodes::_fastore :
1032           current_frame.pop_stack(
1033             VerificationType::float_type(), CHECK_VERIFY(this));
1034           current_frame.pop_stack
1035             (VerificationType::integer_type(), CHECK_VERIFY(this));
1036           atype = current_frame.pop_stack(
1037             VerificationType::reference_check(), CHECK_VERIFY(this));
1038           if (!atype.is_float_array()) {
1039             verify_error(ErrorContext::bad_type(bci,
1040                 current_frame.stack_top_ctx(), ref_ctx("[F", THREAD)),
1041                 bad_type_msg, "fastore");
1042             return;
1043           }
1044           no_control_flow = false; break;
1045         case Bytecodes::_dastore :
1046           current_frame.pop_stack_2(
1047             VerificationType::double2_type(),
1048             VerificationType::double_type(), CHECK_VERIFY(this));
1049           current_frame.pop_stack(
1050             VerificationType::integer_type(), CHECK_VERIFY(this));
1051           atype = current_frame.pop_stack(
1052             VerificationType::reference_check(), CHECK_VERIFY(this));
1053           if (!atype.is_double_array()) {
1054             verify_error(ErrorContext::bad_type(bci,
1055                 current_frame.stack_top_ctx(), ref_ctx("[D", THREAD)),
1056                 bad_type_msg, "dastore");
1057             return;
1058           }
1059           no_control_flow = false; break;
1060         case Bytecodes::_aastore :
1061           type = current_frame.pop_stack(object_type(), CHECK_VERIFY(this));
1062           type2 = current_frame.pop_stack(
1063             VerificationType::integer_type(), CHECK_VERIFY(this));
1064           atype = current_frame.pop_stack(
1065             VerificationType::reference_check(), CHECK_VERIFY(this));
1066           // more type-checking is done at runtime
1067           if (!atype.is_reference_array()) {
1068             verify_error(ErrorContext::bad_type(bci,
1069                 current_frame.stack_top_ctx(),
1070                 TypeOrigin::implicit(VerificationType::reference_check())),
1071                 bad_type_msg, "aastore");
1072             return;
1073           }
1074           // 4938384: relaxed constraint in JVMS 3nd edition.
1075           no_control_flow = false; break;
1076         case Bytecodes::_pop :
1077           current_frame.pop_stack(
1078             VerificationType::category1_check(), CHECK_VERIFY(this));
1079           no_control_flow = false; break;
1080         case Bytecodes::_pop2 :
1081           type = current_frame.pop_stack(CHECK_VERIFY(this));
1082           if (type.is_category1()) {
1083             current_frame.pop_stack(
1084               VerificationType::category1_check(), CHECK_VERIFY(this));
1085           } else if (type.is_category2_2nd()) {
1086             current_frame.pop_stack(
1087               VerificationType::category2_check(), CHECK_VERIFY(this));
1088           } else {
1089             /* Unreachable? Would need a category2_1st on TOS
1090              * which does not appear possible. */
1091             verify_error(
1092                 ErrorContext::bad_type(bci, current_frame.stack_top_ctx()),
1093                 bad_type_msg, "pop2");
1094             return;
1095           }
1096           no_control_flow = false; break;
1097         case Bytecodes::_dup :
1098           type = current_frame.pop_stack(
1099             VerificationType::category1_check(), CHECK_VERIFY(this));
1100           current_frame.push_stack(type, CHECK_VERIFY(this));
1101           current_frame.push_stack(type, CHECK_VERIFY(this));
1102           no_control_flow = false; break;
1103         case Bytecodes::_dup_x1 :
1104           type = current_frame.pop_stack(
1105             VerificationType::category1_check(), CHECK_VERIFY(this));
1106           type2 = current_frame.pop_stack(
1107             VerificationType::category1_check(), CHECK_VERIFY(this));
1108           current_frame.push_stack(type, CHECK_VERIFY(this));
1109           current_frame.push_stack(type2, CHECK_VERIFY(this));
1110           current_frame.push_stack(type, CHECK_VERIFY(this));
1111           no_control_flow = false; break;
1112         case Bytecodes::_dup_x2 :
1113         {
1114           VerificationType type3;
1115           type = current_frame.pop_stack(
1116             VerificationType::category1_check(), CHECK_VERIFY(this));
1117           type2 = current_frame.pop_stack(CHECK_VERIFY(this));
1118           if (type2.is_category1()) {
1119             type3 = current_frame.pop_stack(
1120               VerificationType::category1_check(), CHECK_VERIFY(this));
1121           } else if (type2.is_category2_2nd()) {
1122             type3 = current_frame.pop_stack(
1123               VerificationType::category2_check(), CHECK_VERIFY(this));
1124           } else {
1125             /* Unreachable? Would need a category2_1st at stack depth 2 with
1126              * a category1 on TOS which does not appear possible. */
1127             verify_error(ErrorContext::bad_type(
1128                 bci, current_frame.stack_top_ctx()), bad_type_msg, "dup_x2");
1129             return;
1130           }
1131           current_frame.push_stack(type, CHECK_VERIFY(this));
1132           current_frame.push_stack(type3, CHECK_VERIFY(this));
1133           current_frame.push_stack(type2, CHECK_VERIFY(this));
1134           current_frame.push_stack(type, CHECK_VERIFY(this));
1135           no_control_flow = false; break;
1136         }
1137         case Bytecodes::_dup2 :
1138           type = current_frame.pop_stack(CHECK_VERIFY(this));
1139           if (type.is_category1()) {
1140             type2 = current_frame.pop_stack(
1141               VerificationType::category1_check(), CHECK_VERIFY(this));
1142           } else if (type.is_category2_2nd()) {
1143             type2 = current_frame.pop_stack(
1144               VerificationType::category2_check(), CHECK_VERIFY(this));
1145           } else {
1146             /* Unreachable?  Would need a category2_1st on TOS which does not
1147              * appear possible. */
1148             verify_error(
1149                 ErrorContext::bad_type(bci, current_frame.stack_top_ctx()),
1150                 bad_type_msg, "dup2");
1151             return;
1152           }
1153           current_frame.push_stack(type2, CHECK_VERIFY(this));
1154           current_frame.push_stack(type, CHECK_VERIFY(this));
1155           current_frame.push_stack(type2, CHECK_VERIFY(this));
1156           current_frame.push_stack(type, CHECK_VERIFY(this));
1157           no_control_flow = false; break;
1158         case Bytecodes::_dup2_x1 :
1159         {
1160           VerificationType type3;
1161           type = current_frame.pop_stack(CHECK_VERIFY(this));
1162           if (type.is_category1()) {
1163             type2 = current_frame.pop_stack(
1164               VerificationType::category1_check(), CHECK_VERIFY(this));
1165           } else if (type.is_category2_2nd()) {
1166             type2 = current_frame.pop_stack(
1167               VerificationType::category2_check(), CHECK_VERIFY(this));
1168           } else {
1169             /* Unreachable?  Would need a category2_1st on TOS which does
1170              * not appear possible. */
1171             verify_error(
1172                 ErrorContext::bad_type(bci, current_frame.stack_top_ctx()),
1173                 bad_type_msg, "dup2_x1");
1174             return;
1175           }
1176           type3 = current_frame.pop_stack(
1177             VerificationType::category1_check(), CHECK_VERIFY(this));
1178           current_frame.push_stack(type2, CHECK_VERIFY(this));
1179           current_frame.push_stack(type, CHECK_VERIFY(this));
1180           current_frame.push_stack(type3, CHECK_VERIFY(this));
1181           current_frame.push_stack(type2, CHECK_VERIFY(this));
1182           current_frame.push_stack(type, CHECK_VERIFY(this));
1183           no_control_flow = false; break;
1184         }
1185         case Bytecodes::_dup2_x2 :
1186         {
1187           VerificationType type3, type4;
1188           type = current_frame.pop_stack(CHECK_VERIFY(this));
1189           if (type.is_category1()) {
1190             type2 = current_frame.pop_stack(
1191               VerificationType::category1_check(), CHECK_VERIFY(this));
1192           } else if (type.is_category2_2nd()) {
1193             type2 = current_frame.pop_stack(
1194               VerificationType::category2_check(), CHECK_VERIFY(this));
1195           } else {
1196             /* Unreachable?  Would need a category2_1st on TOS which does
1197              * not appear possible. */
1198             verify_error(
1199                 ErrorContext::bad_type(bci, current_frame.stack_top_ctx()),
1200                 bad_type_msg, "dup2_x2");
1201             return;
1202           }
1203           type3 = current_frame.pop_stack(CHECK_VERIFY(this));
1204           if (type3.is_category1()) {
1205             type4 = current_frame.pop_stack(
1206               VerificationType::category1_check(), CHECK_VERIFY(this));
1207           } else if (type3.is_category2_2nd()) {
1208             type4 = current_frame.pop_stack(
1209               VerificationType::category2_check(), CHECK_VERIFY(this));
1210           } else {
1211             /* Unreachable?  Would need a category2_1st on TOS after popping
1212              * a long/double or two category 1's, which does not
1213              * appear possible. */
1214             verify_error(
1215                 ErrorContext::bad_type(bci, current_frame.stack_top_ctx()),
1216                 bad_type_msg, "dup2_x2");
1217             return;
1218           }
1219           current_frame.push_stack(type2, CHECK_VERIFY(this));
1220           current_frame.push_stack(type, CHECK_VERIFY(this));
1221           current_frame.push_stack(type4, CHECK_VERIFY(this));
1222           current_frame.push_stack(type3, CHECK_VERIFY(this));
1223           current_frame.push_stack(type2, CHECK_VERIFY(this));
1224           current_frame.push_stack(type, CHECK_VERIFY(this));
1225           no_control_flow = false; break;
1226         }
1227         case Bytecodes::_swap :
1228           type = current_frame.pop_stack(
1229             VerificationType::category1_check(), CHECK_VERIFY(this));
1230           type2 = current_frame.pop_stack(
1231             VerificationType::category1_check(), CHECK_VERIFY(this));
1232           current_frame.push_stack(type, CHECK_VERIFY(this));
1233           current_frame.push_stack(type2, CHECK_VERIFY(this));
1234           no_control_flow = false; break;
1235         case Bytecodes::_iadd :
1236         case Bytecodes::_isub :
1237         case Bytecodes::_imul :
1238         case Bytecodes::_idiv :
1239         case Bytecodes::_irem :
1240         case Bytecodes::_ishl :
1241         case Bytecodes::_ishr :
1242         case Bytecodes::_iushr :
1243         case Bytecodes::_ior :
1244         case Bytecodes::_ixor :
1245         case Bytecodes::_iand :
1246           current_frame.pop_stack(
1247             VerificationType::integer_type(), CHECK_VERIFY(this));
1248           // fall through
1249         case Bytecodes::_ineg :
1250           current_frame.pop_stack(
1251             VerificationType::integer_type(), CHECK_VERIFY(this));
1252           current_frame.push_stack(
1253             VerificationType::integer_type(), CHECK_VERIFY(this));
1254           no_control_flow = false; break;
1255         case Bytecodes::_ladd :
1256         case Bytecodes::_lsub :
1257         case Bytecodes::_lmul :
1258         case Bytecodes::_ldiv :
1259         case Bytecodes::_lrem :
1260         case Bytecodes::_land :
1261         case Bytecodes::_lor :
1262         case Bytecodes::_lxor :
1263           current_frame.pop_stack_2(
1264             VerificationType::long2_type(),
1265             VerificationType::long_type(), CHECK_VERIFY(this));
1266           // fall through
1267         case Bytecodes::_lneg :
1268           current_frame.pop_stack_2(
1269             VerificationType::long2_type(),
1270             VerificationType::long_type(), CHECK_VERIFY(this));
1271           current_frame.push_stack_2(
1272             VerificationType::long_type(),
1273             VerificationType::long2_type(), CHECK_VERIFY(this));
1274           no_control_flow = false; break;
1275         case Bytecodes::_lshl :
1276         case Bytecodes::_lshr :
1277         case Bytecodes::_lushr :
1278           current_frame.pop_stack(
1279             VerificationType::integer_type(), CHECK_VERIFY(this));
1280           current_frame.pop_stack_2(
1281             VerificationType::long2_type(),
1282             VerificationType::long_type(), CHECK_VERIFY(this));
1283           current_frame.push_stack_2(
1284             VerificationType::long_type(),
1285             VerificationType::long2_type(), CHECK_VERIFY(this));
1286           no_control_flow = false; break;
1287         case Bytecodes::_fadd :
1288         case Bytecodes::_fsub :
1289         case Bytecodes::_fmul :
1290         case Bytecodes::_fdiv :
1291         case Bytecodes::_frem :
1292           current_frame.pop_stack(
1293             VerificationType::float_type(), CHECK_VERIFY(this));
1294           // fall through
1295         case Bytecodes::_fneg :
1296           current_frame.pop_stack(
1297             VerificationType::float_type(), CHECK_VERIFY(this));
1298           current_frame.push_stack(
1299             VerificationType::float_type(), CHECK_VERIFY(this));
1300           no_control_flow = false; break;
1301         case Bytecodes::_dadd :
1302         case Bytecodes::_dsub :
1303         case Bytecodes::_dmul :
1304         case Bytecodes::_ddiv :
1305         case Bytecodes::_drem :
1306           current_frame.pop_stack_2(
1307             VerificationType::double2_type(),
1308             VerificationType::double_type(), CHECK_VERIFY(this));
1309           // fall through
1310         case Bytecodes::_dneg :
1311           current_frame.pop_stack_2(
1312             VerificationType::double2_type(),
1313             VerificationType::double_type(), CHECK_VERIFY(this));
1314           current_frame.push_stack_2(
1315             VerificationType::double_type(),
1316             VerificationType::double2_type(), CHECK_VERIFY(this));
1317           no_control_flow = false; break;
1318         case Bytecodes::_iinc :
1319           verify_iinc(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
1320           no_control_flow = false; break;
1321         case Bytecodes::_i2l :
1322           type = current_frame.pop_stack(
1323             VerificationType::integer_type(), CHECK_VERIFY(this));
1324           current_frame.push_stack_2(
1325             VerificationType::long_type(),
1326             VerificationType::long2_type(), CHECK_VERIFY(this));
1327           no_control_flow = false; break;
1328        case Bytecodes::_l2i :
1329           current_frame.pop_stack_2(
1330             VerificationType::long2_type(),
1331             VerificationType::long_type(), CHECK_VERIFY(this));
1332           current_frame.push_stack(
1333             VerificationType::integer_type(), CHECK_VERIFY(this));
1334           no_control_flow = false; break;
1335         case Bytecodes::_i2f :
1336           current_frame.pop_stack(
1337             VerificationType::integer_type(), CHECK_VERIFY(this));
1338           current_frame.push_stack(
1339             VerificationType::float_type(), CHECK_VERIFY(this));
1340           no_control_flow = false; break;
1341         case Bytecodes::_i2d :
1342           current_frame.pop_stack(
1343             VerificationType::integer_type(), CHECK_VERIFY(this));
1344           current_frame.push_stack_2(
1345             VerificationType::double_type(),
1346             VerificationType::double2_type(), CHECK_VERIFY(this));
1347           no_control_flow = false; break;
1348         case Bytecodes::_l2f :
1349           current_frame.pop_stack_2(
1350             VerificationType::long2_type(),
1351             VerificationType::long_type(), CHECK_VERIFY(this));
1352           current_frame.push_stack(
1353             VerificationType::float_type(), CHECK_VERIFY(this));
1354           no_control_flow = false; break;
1355         case Bytecodes::_l2d :
1356           current_frame.pop_stack_2(
1357             VerificationType::long2_type(),
1358             VerificationType::long_type(), CHECK_VERIFY(this));
1359           current_frame.push_stack_2(
1360             VerificationType::double_type(),
1361             VerificationType::double2_type(), CHECK_VERIFY(this));
1362           no_control_flow = false; break;
1363         case Bytecodes::_f2i :
1364           current_frame.pop_stack(
1365             VerificationType::float_type(), CHECK_VERIFY(this));
1366           current_frame.push_stack(
1367             VerificationType::integer_type(), CHECK_VERIFY(this));
1368           no_control_flow = false; break;
1369         case Bytecodes::_f2l :
1370           current_frame.pop_stack(
1371             VerificationType::float_type(), CHECK_VERIFY(this));
1372           current_frame.push_stack_2(
1373             VerificationType::long_type(),
1374             VerificationType::long2_type(), CHECK_VERIFY(this));
1375           no_control_flow = false; break;
1376         case Bytecodes::_f2d :
1377           current_frame.pop_stack(
1378             VerificationType::float_type(), CHECK_VERIFY(this));
1379           current_frame.push_stack_2(
1380             VerificationType::double_type(),
1381             VerificationType::double2_type(), CHECK_VERIFY(this));
1382           no_control_flow = false; break;
1383         case Bytecodes::_d2i :
1384           current_frame.pop_stack_2(
1385             VerificationType::double2_type(),
1386             VerificationType::double_type(), CHECK_VERIFY(this));
1387           current_frame.push_stack(
1388             VerificationType::integer_type(), CHECK_VERIFY(this));
1389           no_control_flow = false; break;
1390         case Bytecodes::_d2l :
1391           current_frame.pop_stack_2(
1392             VerificationType::double2_type(),
1393             VerificationType::double_type(), CHECK_VERIFY(this));
1394           current_frame.push_stack_2(
1395             VerificationType::long_type(),
1396             VerificationType::long2_type(), CHECK_VERIFY(this));
1397           no_control_flow = false; break;
1398         case Bytecodes::_d2f :
1399           current_frame.pop_stack_2(
1400             VerificationType::double2_type(),
1401             VerificationType::double_type(), CHECK_VERIFY(this));
1402           current_frame.push_stack(
1403             VerificationType::float_type(), CHECK_VERIFY(this));
1404           no_control_flow = false; break;
1405         case Bytecodes::_i2b :
1406         case Bytecodes::_i2c :
1407         case Bytecodes::_i2s :
1408           current_frame.pop_stack(
1409             VerificationType::integer_type(), CHECK_VERIFY(this));
1410           current_frame.push_stack(
1411             VerificationType::integer_type(), CHECK_VERIFY(this));
1412           no_control_flow = false; break;
1413         case Bytecodes::_lcmp :
1414           current_frame.pop_stack_2(
1415             VerificationType::long2_type(),
1416             VerificationType::long_type(), CHECK_VERIFY(this));
1417           current_frame.pop_stack_2(
1418             VerificationType::long2_type(),
1419             VerificationType::long_type(), CHECK_VERIFY(this));
1420           current_frame.push_stack(
1421             VerificationType::integer_type(), CHECK_VERIFY(this));
1422           no_control_flow = false; break;
1423         case Bytecodes::_fcmpl :
1424         case Bytecodes::_fcmpg :
1425           current_frame.pop_stack(
1426             VerificationType::float_type(), CHECK_VERIFY(this));
1427           current_frame.pop_stack(
1428             VerificationType::float_type(), CHECK_VERIFY(this));
1429           current_frame.push_stack(
1430             VerificationType::integer_type(), CHECK_VERIFY(this));
1431           no_control_flow = false; break;
1432         case Bytecodes::_dcmpl :
1433         case Bytecodes::_dcmpg :
1434           current_frame.pop_stack_2(
1435             VerificationType::double2_type(),
1436             VerificationType::double_type(), CHECK_VERIFY(this));
1437           current_frame.pop_stack_2(
1438             VerificationType::double2_type(),
1439             VerificationType::double_type(), CHECK_VERIFY(this));
1440           current_frame.push_stack(
1441             VerificationType::integer_type(), CHECK_VERIFY(this));
1442           no_control_flow = false; break;
1443         case Bytecodes::_if_icmpeq:
1444         case Bytecodes::_if_icmpne:
1445         case Bytecodes::_if_icmplt:
1446         case Bytecodes::_if_icmpge:
1447         case Bytecodes::_if_icmpgt:
1448         case Bytecodes::_if_icmple:
1449           current_frame.pop_stack(
1450             VerificationType::integer_type(), CHECK_VERIFY(this));
1451           // fall through
1452         case Bytecodes::_ifeq:
1453         case Bytecodes::_ifne:
1454         case Bytecodes::_iflt:
1455         case Bytecodes::_ifge:
1456         case Bytecodes::_ifgt:
1457         case Bytecodes::_ifle:
1458           current_frame.pop_stack(
1459             VerificationType::integer_type(), CHECK_VERIFY(this));
1460           target = bcs.dest();
1461           stackmap_table.check_jump_target(
1462             &current_frame, target, CHECK_VERIFY(this));
1463           no_control_flow = false; break;
1464         case Bytecodes::_if_acmpeq :
1465         case Bytecodes::_if_acmpne :
1466           current_frame.pop_stack(
1467             VerificationType::reference_check(), CHECK_VERIFY(this));
1468           // fall through
1469         case Bytecodes::_ifnull :
1470         case Bytecodes::_ifnonnull :
1471           current_frame.pop_stack(
1472             VerificationType::reference_check(), CHECK_VERIFY(this));
1473           target = bcs.dest();
1474           stackmap_table.check_jump_target
1475             (&current_frame, target, CHECK_VERIFY(this));
1476           no_control_flow = false; break;
1477         case Bytecodes::_goto :
1478           target = bcs.dest();
1479           stackmap_table.check_jump_target(
1480             &current_frame, target, CHECK_VERIFY(this));
1481           no_control_flow = true; break;
1482         case Bytecodes::_goto_w :
1483           target = bcs.dest_w();
1484           stackmap_table.check_jump_target(
1485             &current_frame, target, CHECK_VERIFY(this));
1486           no_control_flow = true; break;
1487         case Bytecodes::_tableswitch :
1488         case Bytecodes::_lookupswitch :
1489           verify_switch(
1490             &bcs, code_length, code_data, &current_frame,
1491             &stackmap_table, CHECK_VERIFY(this));
1492           no_control_flow = true; break;
1493         case Bytecodes::_ireturn :
1494           type = current_frame.pop_stack(
1495             VerificationType::integer_type(), CHECK_VERIFY(this));
1496           verify_return_value(return_type, type, bci,
1497                               &current_frame, CHECK_VERIFY(this));
1498           no_control_flow = true; break;
1499         case Bytecodes::_lreturn :
1500           type2 = current_frame.pop_stack(
1501             VerificationType::long2_type(), CHECK_VERIFY(this));
1502           type = current_frame.pop_stack(
1503             VerificationType::long_type(), CHECK_VERIFY(this));
1504           verify_return_value(return_type, type, bci,
1505                               &current_frame, CHECK_VERIFY(this));
1506           no_control_flow = true; break;
1507         case Bytecodes::_freturn :
1508           type = current_frame.pop_stack(
1509             VerificationType::float_type(), CHECK_VERIFY(this));
1510           verify_return_value(return_type, type, bci,
1511                               &current_frame, CHECK_VERIFY(this));
1512           no_control_flow = true; break;
1513         case Bytecodes::_dreturn :
1514           type2 = current_frame.pop_stack(
1515             VerificationType::double2_type(),  CHECK_VERIFY(this));
1516           type = current_frame.pop_stack(
1517             VerificationType::double_type(), CHECK_VERIFY(this));
1518           verify_return_value(return_type, type, bci,
1519                               &current_frame, CHECK_VERIFY(this));
1520           no_control_flow = true; break;
1521         case Bytecodes::_areturn :
1522           type = current_frame.pop_stack(
1523             VerificationType::reference_check(), CHECK_VERIFY(this));
1524           verify_return_value(return_type, type, bci,
1525                               &current_frame, CHECK_VERIFY(this));
1526           no_control_flow = true; break;
1527         case Bytecodes::_return :
1528           if (return_type != VerificationType::bogus_type()) {
1529             verify_error(ErrorContext::bad_code(bci),
1530                          "Method expects a return value");
1531             return;
1532           }
1533           // Make sure "this" has been initialized if current method is an
1534           // <init>
1535           if (_method->name() == vmSymbols::object_initializer_name() &&
1536               current_frame.flag_this_uninit()) {
1537             verify_error(ErrorContext::bad_code(bci),
1538                          "Constructor must call super() or this() "
1539                          "before return");
1540             return;
1541           }
1542           no_control_flow = true; break;
1543         case Bytecodes::_getstatic :
1544         case Bytecodes::_putstatic :
1545         case Bytecodes::_getfield :
1546         case Bytecodes::_putfield :
1547           verify_field_instructions(
1548             &bcs, &current_frame, cp, CHECK_VERIFY(this));
1549           no_control_flow = false; break;
1550         case Bytecodes::_invokevirtual :
1551         case Bytecodes::_invokespecial :
1552         case Bytecodes::_invokestatic :
1553           verify_invoke_instructions(
1554             &bcs, code_length, &current_frame,
1555             &this_uninit, return_type, cp, CHECK_VERIFY(this));
1556           no_control_flow = false; break;
1557         case Bytecodes::_invokeinterface :
1558         case Bytecodes::_invokedynamic :
1559           verify_invoke_instructions(
1560             &bcs, code_length, &current_frame,
1561             &this_uninit, return_type, cp, CHECK_VERIFY(this));
1562           no_control_flow = false; break;
1563         case Bytecodes::_new :
1564         {
1565           index = bcs.get_index_u2();
1566           verify_cp_class_type(bci, index, cp, CHECK_VERIFY(this));
1567           VerificationType new_class_type =
1568             cp_index_to_type(index, cp, CHECK_VERIFY(this));
1569           if (!new_class_type.is_object()) {
1570             verify_error(ErrorContext::bad_type(bci,
1571                 TypeOrigin::cp(index, new_class_type)),
1572                 "Illegal new instruction");
1573             return;
1574           }
1575           type = VerificationType::uninitialized_type(bci);
1576           current_frame.push_stack(type, CHECK_VERIFY(this));
1577           no_control_flow = false; break;
1578         }
1579         case Bytecodes::_newarray :
1580           type = get_newarray_type(bcs.get_index(), bci, CHECK_VERIFY(this));
1581           current_frame.pop_stack(
1582             VerificationType::integer_type(),  CHECK_VERIFY(this));
1583           current_frame.push_stack(type, CHECK_VERIFY(this));
1584           no_control_flow = false; break;
1585         case Bytecodes::_anewarray :
1586           verify_anewarray(
1587             bci, bcs.get_index_u2(), cp, &current_frame, CHECK_VERIFY(this));
1588           no_control_flow = false; break;
1589         case Bytecodes::_arraylength :
1590           type = current_frame.pop_stack(
1591             VerificationType::reference_check(), CHECK_VERIFY(this));
1592           if (!(type.is_null() || type.is_array())) {
1593             verify_error(ErrorContext::bad_type(
1594                 bci, current_frame.stack_top_ctx()),
1595                 bad_type_msg, "arraylength");
1596           }
1597           current_frame.push_stack(
1598             VerificationType::integer_type(), CHECK_VERIFY(this));
1599           no_control_flow = false; break;
1600         case Bytecodes::_checkcast :
1601         {
1602           index = bcs.get_index_u2();
1603           verify_cp_class_type(bci, index, cp, CHECK_VERIFY(this));
1604           current_frame.pop_stack(object_type(), CHECK_VERIFY(this));
1605           VerificationType klass_type = cp_index_to_type(
1606             index, cp, CHECK_VERIFY(this));
1607           current_frame.push_stack(klass_type, CHECK_VERIFY(this));
1608           no_control_flow = false; break;
1609         }
1610         case Bytecodes::_instanceof : {
1611           index = bcs.get_index_u2();
1612           verify_cp_class_type(bci, index, cp, CHECK_VERIFY(this));
1613           current_frame.pop_stack(object_type(), CHECK_VERIFY(this));
1614           current_frame.push_stack(
1615             VerificationType::integer_type(), CHECK_VERIFY(this));
1616           no_control_flow = false; break;
1617         }
1618         case Bytecodes::_monitorenter :
1619         case Bytecodes::_monitorexit :
1620           current_frame.pop_stack(
1621             VerificationType::reference_check(), CHECK_VERIFY(this));
1622           no_control_flow = false; break;
1623         case Bytecodes::_multianewarray :
1624         {
1625           index = bcs.get_index_u2();
1626           u2 dim = *(bcs.bcp()+3);
1627           verify_cp_class_type(bci, index, cp, CHECK_VERIFY(this));
1628           VerificationType new_array_type =
1629             cp_index_to_type(index, cp, CHECK_VERIFY(this));
1630           if (!new_array_type.is_array()) {
1631             verify_error(ErrorContext::bad_type(bci,
1632                 TypeOrigin::cp(index, new_array_type)),
1633                 "Illegal constant pool index in multianewarray instruction");
1634             return;
1635           }
1636           if (dim < 1 || new_array_type.dimensions() < dim) {
1637             verify_error(ErrorContext::bad_code(bci),
1638                 "Illegal dimension in multianewarray instruction: %d", dim);
1639             return;
1640           }
1641           for (int i = 0; i < dim; i++) {
1642             current_frame.pop_stack(
1643               VerificationType::integer_type(), CHECK_VERIFY(this));
1644           }
1645           current_frame.push_stack(new_array_type, CHECK_VERIFY(this));
1646           no_control_flow = false; break;
1647         }
1648         case Bytecodes::_athrow :
1649           type = VerificationType::reference_type(
1650             vmSymbols::java_lang_Throwable());
1651           current_frame.pop_stack(type, CHECK_VERIFY(this));
1652           no_control_flow = true; break;
1653         default:
1654           // We only need to check the valid bytecodes in class file.
1655           // And jsr and ret are not in the new class file format in JDK1.5.
1656           verify_error(ErrorContext::bad_code(bci),
1657               "Bad instruction: %02x", opcode);
1658           no_control_flow = false;
1659           return;
1660       }  // end switch
1661     }  // end Merge with the next instruction
1662 
1663     // Look for possible jump target in exception handlers and see if it
1664     // matches current_frame
1665     if (bci >= ex_min && bci < ex_max) {
1666       verify_exception_handler_targets(
1667         bci, this_uninit, &current_frame, &stackmap_table, CHECK_VERIFY(this));
1668     }
1669   } // end while
1670 
1671   // Make sure that control flow does not fall through end of the method
1672   if (!no_control_flow) {
1673     verify_error(ErrorContext::bad_code(code_length),
1674         "Control flow falls through code end");
1675     return;
1676   }
1677 }
1678 
1679 char* ClassVerifier::generate_code_data(methodHandle m, u4 code_length, TRAPS) {
1680   char* code_data = NEW_RESOURCE_ARRAY(char, code_length);
1681   memset(code_data, 0, sizeof(char) * code_length);
1682   RawBytecodeStream bcs(m);
1683 
1684   while (!bcs.is_last_bytecode()) {
1685     if (bcs.raw_next() != Bytecodes::_illegal) {
1686       int bci = bcs.bci();
1687       if (bcs.raw_code() == Bytecodes::_new) {
1688         code_data[bci] = NEW_OFFSET;
1689       } else {
1690         code_data[bci] = BYTECODE_OFFSET;
1691       }
1692     } else {
1693       verify_error(ErrorContext::bad_code(bcs.bci()), "Bad instruction");
1694       return NULL;
1695     }
1696   }
1697 
1698   return code_data;
1699 }
1700 
1701 void ClassVerifier::verify_exception_handler_table(u4 code_length, char* code_data, int& min, int& max, TRAPS) {
1702   ExceptionTable exhandlers(_method());
1703   int exlength = exhandlers.length();
1704   constantPoolHandle cp (THREAD, _method->constants());
1705 
1706   for(int i = 0; i < exlength; i++) {
1707     //reacquire the table in case a GC happened
1708     ExceptionTable exhandlers(_method());
1709     u2 start_pc = exhandlers.start_pc(i);
1710     u2 end_pc = exhandlers.end_pc(i);
1711     u2 handler_pc = exhandlers.handler_pc(i);
1712     if (start_pc >= code_length || code_data[start_pc] == 0) {
1713       class_format_error("Illegal exception table start_pc %d", start_pc);
1714       return;
1715     }
1716     if (end_pc != code_length) {   // special case: end_pc == code_length
1717       if (end_pc > code_length || code_data[end_pc] == 0) {
1718         class_format_error("Illegal exception table end_pc %d", end_pc);
1719         return;
1720       }
1721     }
1722     if (handler_pc >= code_length || code_data[handler_pc] == 0) {
1723       class_format_error("Illegal exception table handler_pc %d", handler_pc);
1724       return;
1725     }
1726     int catch_type_index = exhandlers.catch_type_index(i);
1727     if (catch_type_index != 0) {
1728       VerificationType catch_type = cp_index_to_type(
1729         catch_type_index, cp, CHECK_VERIFY(this));
1730       VerificationType throwable =
1731         VerificationType::reference_type(vmSymbols::java_lang_Throwable());
1732       bool is_subclass = throwable.is_assignable_from(
1733         catch_type, this, CHECK_VERIFY(this));
1734       if (!is_subclass) {
1735         // 4286534: should throw VerifyError according to recent spec change
1736         verify_error(ErrorContext::bad_type(handler_pc,
1737             TypeOrigin::cp(catch_type_index, catch_type),
1738             TypeOrigin::implicit(throwable)),
1739             "Catch type is not a subclass "
1740             "of Throwable in exception handler %d", handler_pc);
1741         return;
1742       }
1743     }
1744     if (start_pc < min) min = start_pc;
1745     if (end_pc > max) max = end_pc;
1746   }
1747 }
1748 
1749 void ClassVerifier::verify_local_variable_table(u4 code_length, char* code_data, TRAPS) {
1750   int localvariable_table_length = _method()->localvariable_table_length();
1751   if (localvariable_table_length > 0) {
1752     LocalVariableTableElement* table = _method()->localvariable_table_start();
1753     for (int i = 0; i < localvariable_table_length; i++) {
1754       u2 start_bci = table[i].start_bci;
1755       u2 length = table[i].length;
1756 
1757       if (start_bci >= code_length || code_data[start_bci] == 0) {
1758         class_format_error(
1759           "Illegal local variable table start_pc %d", start_bci);
1760         return;
1761       }
1762       u4 end_bci = (u4)(start_bci + length);
1763       if (end_bci != code_length) {
1764         if (end_bci >= code_length || code_data[end_bci] == 0) {
1765           class_format_error( "Illegal local variable table length %d", length);
1766           return;
1767         }
1768       }
1769     }
1770   }
1771 }
1772 
1773 u2 ClassVerifier::verify_stackmap_table(u2 stackmap_index, u2 bci,
1774                                         StackMapFrame* current_frame,
1775                                         StackMapTable* stackmap_table,
1776                                         bool no_control_flow, TRAPS) {
1777   if (stackmap_index < stackmap_table->get_frame_count()) {
1778     u2 this_offset = stackmap_table->get_offset(stackmap_index);
1779     if (no_control_flow && this_offset > bci) {
1780       verify_error(ErrorContext::missing_stackmap(bci),
1781                    "Expecting a stack map frame");
1782       return 0;
1783     }
1784     if (this_offset == bci) {
1785       ErrorContext ctx;
1786       // See if current stack map can be assigned to the frame in table.
1787       // current_frame is the stackmap frame got from the last instruction.
1788       // If matched, current_frame will be updated by this method.
1789       bool matches = stackmap_table->match_stackmap(
1790         current_frame, this_offset, stackmap_index,
1791         !no_control_flow, true, &ctx, CHECK_VERIFY_(this, 0));
1792       if (!matches) {
1793         // report type error
1794         verify_error(ctx, "Instruction type does not match stack map");
1795         return 0;
1796       }
1797       stackmap_index++;
1798     } else if (this_offset < bci) {
1799       // current_offset should have met this_offset.
1800       class_format_error("Bad stack map offset %d", this_offset);
1801       return 0;
1802     }
1803   } else if (no_control_flow) {
1804     verify_error(ErrorContext::bad_code(bci), "Expecting a stack map frame");
1805     return 0;
1806   }
1807   return stackmap_index;
1808 }
1809 
1810 void ClassVerifier::verify_exception_handler_targets(u2 bci, bool this_uninit, StackMapFrame* current_frame,
1811                                                      StackMapTable* stackmap_table, TRAPS) {
1812   constantPoolHandle cp (THREAD, _method->constants());
1813   ExceptionTable exhandlers(_method());
1814   int exlength = exhandlers.length();
1815   for(int i = 0; i < exlength; i++) {
1816     //reacquire the table in case a GC happened
1817     ExceptionTable exhandlers(_method());
1818     u2 start_pc = exhandlers.start_pc(i);
1819     u2 end_pc = exhandlers.end_pc(i);
1820     u2 handler_pc = exhandlers.handler_pc(i);
1821     int catch_type_index = exhandlers.catch_type_index(i);
1822     if(bci >= start_pc && bci < end_pc) {
1823       u1 flags = current_frame->flags();
1824       if (this_uninit) {  flags |= FLAG_THIS_UNINIT; }
1825       StackMapFrame* new_frame = current_frame->frame_in_exception_handler(flags);
1826       if (catch_type_index != 0) {
1827         // We know that this index refers to a subclass of Throwable
1828         VerificationType catch_type = cp_index_to_type(
1829           catch_type_index, cp, CHECK_VERIFY(this));
1830         new_frame->push_stack(catch_type, CHECK_VERIFY(this));
1831       } else {
1832         VerificationType throwable =
1833           VerificationType::reference_type(vmSymbols::java_lang_Throwable());
1834         new_frame->push_stack(throwable, CHECK_VERIFY(this));
1835       }
1836       ErrorContext ctx;
1837       bool matches = stackmap_table->match_stackmap(
1838         new_frame, handler_pc, true, false, &ctx, CHECK_VERIFY(this));
1839       if (!matches) {
1840         verify_error(ctx, "Stack map does not match the one at "
1841             "exception handler %d", handler_pc);
1842         return;
1843       }
1844     }
1845   }
1846 }
1847 
1848 void ClassVerifier::verify_cp_index(
1849     u2 bci, constantPoolHandle cp, int index, TRAPS) {
1850   int nconstants = cp->length();
1851   if ((index <= 0) || (index >= nconstants)) {
1852     verify_error(ErrorContext::bad_cp_index(bci, index),
1853         "Illegal constant pool index %d in class %s",
1854         index, cp->pool_holder()->external_name());
1855     return;
1856   }
1857 }
1858 
1859 void ClassVerifier::verify_cp_type(
1860     u2 bci, int index, constantPoolHandle cp, unsigned int types, TRAPS) {
1861 
1862   // In some situations, bytecode rewriting may occur while we're verifying.
1863   // In this case, a constant pool cache exists and some indices refer to that
1864   // instead.  Be sure we don't pick up such indices by accident.
1865   // We must check was_recursively_verified() before we get here.
1866   guarantee(cp->cache() == NULL, "not rewritten yet");
1867 
1868   verify_cp_index(bci, cp, index, CHECK_VERIFY(this));
1869   unsigned int tag = cp->tag_at(index).value();
1870   if ((types & (1 << tag)) == 0) {
1871     verify_error(ErrorContext::bad_cp_index(bci, index),
1872       "Illegal type at constant pool entry %d in class %s",
1873       index, cp->pool_holder()->external_name());
1874     return;
1875   }
1876 }
1877 
1878 void ClassVerifier::verify_cp_class_type(
1879     u2 bci, int index, constantPoolHandle cp, TRAPS) {
1880   verify_cp_index(bci, cp, index, CHECK_VERIFY(this));
1881   constantTag tag = cp->tag_at(index);
1882   if (!tag.is_klass() && !tag.is_unresolved_klass()) {
1883     verify_error(ErrorContext::bad_cp_index(bci, index),
1884         "Illegal type at constant pool entry %d in class %s",
1885         index, cp->pool_holder()->external_name());
1886     return;
1887   }
1888 }
1889 
1890 void ClassVerifier::verify_error(ErrorContext ctx, const char* msg, ...) {
1891   stringStream ss;
1892 
1893   ctx.reset_frames();
1894   _exception_type = vmSymbols::java_lang_VerifyError();
1895   _error_context = ctx;
1896   va_list va;
1897   va_start(va, msg);
1898   ss.vprint(msg, va);
1899   va_end(va);
1900   _message = ss.as_string();
1901 #ifdef ASSERT
1902   ResourceMark rm;
1903   const char* exception_name = _exception_type->as_C_string();
1904   Exceptions::debug_check_abort(exception_name, NULL);
1905 #endif // ndef ASSERT
1906 }
1907 
1908 void ClassVerifier::class_format_error(const char* msg, ...) {
1909   stringStream ss;
1910   _exception_type = vmSymbols::java_lang_ClassFormatError();
1911   va_list va;
1912   va_start(va, msg);
1913   ss.vprint(msg, va);
1914   va_end(va);
1915   if (!_method.is_null()) {
1916     ss.print(" in method %s", _method->name_and_sig_as_C_string());
1917   }
1918   _message = ss.as_string();
1919 }
1920 
1921 Klass* ClassVerifier::load_class(Symbol* name, TRAPS) {
1922   // Get current loader and protection domain first.
1923   oop loader = current_class()->class_loader();
1924   oop protection_domain = current_class()->protection_domain();
1925 
1926   return SystemDictionary::resolve_or_fail(
1927     name, Handle(THREAD, loader), Handle(THREAD, protection_domain),
1928     true, CHECK_NULL);
1929 }
1930 
1931 bool ClassVerifier::is_protected_access(instanceKlassHandle this_class,
1932                                         Klass* target_class,
1933                                         Symbol* field_name,
1934                                         Symbol* field_sig,
1935                                         bool is_method) {
1936   No_Safepoint_Verifier nosafepoint;
1937 
1938   // If target class isn't a super class of this class, we don't worry about this case
1939   if (!this_class->is_subclass_of(target_class)) {
1940     return false;
1941   }
1942   // Check if the specified method or field is protected
1943   InstanceKlass* target_instance = InstanceKlass::cast(target_class);
1944   fieldDescriptor fd;
1945   if (is_method) {
1946     Method* m = target_instance->uncached_lookup_method(field_name, field_sig);
1947     if (m != NULL && m->is_protected()) {
1948       if (!this_class->is_same_class_package(m->method_holder())) {
1949         return true;
1950       }
1951     }
1952   } else {
1953     Klass* member_klass = target_instance->find_field(field_name, field_sig, &fd);
1954     if (member_klass != NULL && fd.is_protected()) {
1955       if (!this_class->is_same_class_package(member_klass)) {
1956         return true;
1957       }
1958     }
1959   }
1960   return false;
1961 }
1962 
1963 void ClassVerifier::verify_ldc(
1964     int opcode, u2 index, StackMapFrame* current_frame,
1965     constantPoolHandle cp, u2 bci, TRAPS) {
1966   verify_cp_index(bci, cp, index, CHECK_VERIFY(this));
1967   constantTag tag = cp->tag_at(index);
1968   unsigned int types;
1969   if (opcode == Bytecodes::_ldc || opcode == Bytecodes::_ldc_w) {
1970     if (!tag.is_unresolved_klass()) {
1971       types = (1 << JVM_CONSTANT_Integer) | (1 << JVM_CONSTANT_Float)
1972             | (1 << JVM_CONSTANT_String)  | (1 << JVM_CONSTANT_Class)
1973             | (1 << JVM_CONSTANT_MethodHandle) | (1 << JVM_CONSTANT_MethodType);
1974       // Note:  The class file parser already verified the legality of
1975       // MethodHandle and MethodType constants.
1976       verify_cp_type(bci, index, cp, types, CHECK_VERIFY(this));
1977     }
1978   } else {
1979     assert(opcode == Bytecodes::_ldc2_w, "must be ldc2_w");
1980     types = (1 << JVM_CONSTANT_Double) | (1 << JVM_CONSTANT_Long);
1981     verify_cp_type(bci, index, cp, types, CHECK_VERIFY(this));
1982   }
1983   if (tag.is_string() && cp->is_pseudo_string_at(index)) {
1984     current_frame->push_stack(object_type(), CHECK_VERIFY(this));
1985   } else if (tag.is_string()) {
1986     current_frame->push_stack(
1987       VerificationType::reference_type(
1988         vmSymbols::java_lang_String()), CHECK_VERIFY(this));
1989   } else if (tag.is_klass() || tag.is_unresolved_klass()) {
1990     current_frame->push_stack(
1991       VerificationType::reference_type(
1992         vmSymbols::java_lang_Class()), CHECK_VERIFY(this));
1993   } else if (tag.is_int()) {
1994     current_frame->push_stack(
1995       VerificationType::integer_type(), CHECK_VERIFY(this));
1996   } else if (tag.is_float()) {
1997     current_frame->push_stack(
1998       VerificationType::float_type(), CHECK_VERIFY(this));
1999   } else if (tag.is_double()) {
2000     current_frame->push_stack_2(
2001       VerificationType::double_type(),
2002       VerificationType::double2_type(), CHECK_VERIFY(this));
2003   } else if (tag.is_long()) {
2004     current_frame->push_stack_2(
2005       VerificationType::long_type(),
2006       VerificationType::long2_type(), CHECK_VERIFY(this));
2007   } else if (tag.is_method_handle()) {
2008     current_frame->push_stack(
2009       VerificationType::reference_type(
2010         vmSymbols::java_lang_invoke_MethodHandle()), CHECK_VERIFY(this));
2011   } else if (tag.is_method_type()) {
2012     current_frame->push_stack(
2013       VerificationType::reference_type(
2014         vmSymbols::java_lang_invoke_MethodType()), CHECK_VERIFY(this));
2015   } else {
2016     /* Unreachable? verify_cp_type has already validated the cp type. */
2017     verify_error(
2018         ErrorContext::bad_cp_index(bci, index), "Invalid index in ldc");
2019     return;
2020   }
2021 }
2022 
2023 void ClassVerifier::verify_switch(
2024     RawBytecodeStream* bcs, u4 code_length, char* code_data,
2025     StackMapFrame* current_frame, StackMapTable* stackmap_table, TRAPS) {
2026   int bci = bcs->bci();
2027   address bcp = bcs->bcp();
2028   address aligned_bcp = (address) round_to((intptr_t)(bcp + 1), jintSize);
2029 
2030   if (_klass->major_version() < NONZERO_PADDING_BYTES_IN_SWITCH_MAJOR_VERSION) {
2031     // 4639449 & 4647081: padding bytes must be 0
2032     u2 padding_offset = 1;
2033     while ((bcp + padding_offset) < aligned_bcp) {
2034       if(*(bcp + padding_offset) != 0) {
2035         verify_error(ErrorContext::bad_code(bci),
2036                      "Nonzero padding byte in lookswitch or tableswitch");
2037         return;
2038       }
2039       padding_offset++;
2040     }
2041   }
2042 
2043   int default_offset = (int) Bytes::get_Java_u4(aligned_bcp);
2044   int keys, delta;
2045   current_frame->pop_stack(
2046     VerificationType::integer_type(), CHECK_VERIFY(this));
2047   if (bcs->raw_code() == Bytecodes::_tableswitch) {
2048     jint low = (jint)Bytes::get_Java_u4(aligned_bcp + jintSize);
2049     jint high = (jint)Bytes::get_Java_u4(aligned_bcp + 2*jintSize);
2050     if (low > high) {
2051       verify_error(ErrorContext::bad_code(bci),
2052           "low must be less than or equal to high in tableswitch");
2053       return;
2054     }
2055     keys = high - low + 1;
2056     if (keys < 0) {
2057       verify_error(ErrorContext::bad_code(bci), "too many keys in tableswitch");
2058       return;
2059     }
2060     delta = 1;
2061   } else {
2062     keys = (int)Bytes::get_Java_u4(aligned_bcp + jintSize);
2063     if (keys < 0) {
2064       verify_error(ErrorContext::bad_code(bci),
2065                    "number of keys in lookupswitch less than 0");
2066       return;
2067     }
2068     delta = 2;
2069     // Make sure that the lookupswitch items are sorted
2070     for (int i = 0; i < (keys - 1); i++) {
2071       jint this_key = Bytes::get_Java_u4(aligned_bcp + (2+2*i)*jintSize);
2072       jint next_key = Bytes::get_Java_u4(aligned_bcp + (2+2*i+2)*jintSize);
2073       if (this_key >= next_key) {
2074         verify_error(ErrorContext::bad_code(bci),
2075                      "Bad lookupswitch instruction");
2076         return;
2077       }
2078     }
2079   }
2080   int target = bci + default_offset;
2081   stackmap_table->check_jump_target(current_frame, target, CHECK_VERIFY(this));
2082   for (int i = 0; i < keys; i++) {
2083     // Because check_jump_target() may safepoint, the bytecode could have
2084     // moved, which means 'aligned_bcp' is no good and needs to be recalculated.
2085     aligned_bcp = (address)round_to((intptr_t)(bcs->bcp() + 1), jintSize);
2086     target = bci + (jint)Bytes::get_Java_u4(aligned_bcp+(3+i*delta)*jintSize);
2087     stackmap_table->check_jump_target(
2088       current_frame, target, CHECK_VERIFY(this));
2089   }
2090   NOT_PRODUCT(aligned_bcp = NULL);  // no longer valid at this point
2091 }
2092 
2093 bool ClassVerifier::name_in_supers(
2094     Symbol* ref_name, instanceKlassHandle current) {
2095   Klass* super = current->super();
2096   while (super != NULL) {
2097     if (super->name() == ref_name) {
2098       return true;
2099     }
2100     super = super->super();
2101   }
2102   return false;
2103 }
2104 
2105 void ClassVerifier::verify_field_instructions(RawBytecodeStream* bcs,
2106                                               StackMapFrame* current_frame,
2107                                               constantPoolHandle cp,
2108                                               TRAPS) {
2109   u2 index = bcs->get_index_u2();
2110   verify_cp_type(bcs->bci(), index, cp,
2111       1 << JVM_CONSTANT_Fieldref, CHECK_VERIFY(this));
2112 
2113   // Get field name and signature
2114   Symbol* field_name = cp->name_ref_at(index);
2115   Symbol* field_sig = cp->signature_ref_at(index);
2116 
2117   if (!SignatureVerifier::is_valid_type_signature(field_sig)) {
2118     class_format_error(
2119       "Invalid signature for field in class %s referenced "
2120       "from constant pool index %d", _klass->external_name(), index);
2121     return;
2122   }
2123 
2124   // Get referenced class type
2125   VerificationType ref_class_type = cp_ref_index_to_type(
2126     index, cp, CHECK_VERIFY(this));
2127   if (!ref_class_type.is_object()) {
2128     /* Unreachable?  Class file parser verifies Fieldref contents */
2129     verify_error(ErrorContext::bad_type(bcs->bci(),
2130         TypeOrigin::cp(index, ref_class_type)),
2131         "Expecting reference to class in class %s at constant pool index %d",
2132         _klass->external_name(), index);
2133     return;
2134   }
2135   VerificationType target_class_type = ref_class_type;
2136 
2137   assert(sizeof(VerificationType) == sizeof(uintptr_t),
2138         "buffer type must match VerificationType size");
2139   uintptr_t field_type_buffer[2];
2140   VerificationType* field_type = (VerificationType*)field_type_buffer;
2141   // If we make a VerificationType[2] array directly, the compiler calls
2142   // to the c-runtime library to do the allocation instead of just
2143   // stack allocating it.  Plus it would run constructors.  This shows up
2144   // in performance profiles.
2145 
2146   SignatureStream sig_stream(field_sig, false);
2147   VerificationType stack_object_type;
2148   int n = change_sig_to_verificationType(
2149     &sig_stream, field_type, CHECK_VERIFY(this));
2150   u2 bci = bcs->bci();
2151   bool is_assignable;
2152   switch (bcs->raw_code()) {
2153     case Bytecodes::_getstatic: {
2154       for (int i = 0; i < n; i++) {
2155         current_frame->push_stack(field_type[i], CHECK_VERIFY(this));
2156       }
2157       break;
2158     }
2159     case Bytecodes::_putstatic: {
2160       for (int i = n - 1; i >= 0; i--) {
2161         current_frame->pop_stack(field_type[i], CHECK_VERIFY(this));
2162       }
2163       break;
2164     }
2165     case Bytecodes::_getfield: {
2166       stack_object_type = current_frame->pop_stack(
2167         target_class_type, CHECK_VERIFY(this));
2168       for (int i = 0; i < n; i++) {
2169         current_frame->push_stack(field_type[i], CHECK_VERIFY(this));
2170       }
2171       goto check_protected;
2172     }
2173     case Bytecodes::_putfield: {
2174       for (int i = n - 1; i >= 0; i--) {
2175         current_frame->pop_stack(field_type[i], CHECK_VERIFY(this));
2176       }
2177       stack_object_type = current_frame->pop_stack(CHECK_VERIFY(this));
2178 
2179       // The JVMS 2nd edition allows field initialization before the superclass
2180       // initializer, if the field is defined within the current class.
2181       fieldDescriptor fd;
2182       if (stack_object_type == VerificationType::uninitialized_this_type() &&
2183           target_class_type.equals(current_type()) &&
2184           _klass->find_local_field(field_name, field_sig, &fd)) {
2185         stack_object_type = current_type();
2186       }
2187       is_assignable = target_class_type.is_assignable_from(
2188         stack_object_type, this, CHECK_VERIFY(this));
2189       if (!is_assignable) {
2190         verify_error(ErrorContext::bad_type(bci,
2191             current_frame->stack_top_ctx(),
2192             TypeOrigin::cp(index, target_class_type)),
2193             "Bad type on operand stack in putfield");
2194         return;
2195       }
2196     }
2197     check_protected: {
2198       if (_this_type == stack_object_type)
2199         break; // stack_object_type must be assignable to _current_class_type
2200       Symbol* ref_class_name =
2201         cp->klass_name_at(cp->klass_ref_index_at(index));
2202       if (!name_in_supers(ref_class_name, current_class()))
2203         // stack_object_type must be assignable to _current_class_type since:
2204         // 1. stack_object_type must be assignable to ref_class.
2205         // 2. ref_class must be _current_class or a subclass of it. It can't
2206         //    be a superclass of it. See revised JVMS 5.4.4.
2207         break;
2208 
2209       Klass* ref_class_oop = load_class(ref_class_name, CHECK);
2210       if (is_protected_access(current_class(), ref_class_oop, field_name,
2211                               field_sig, false)) {
2212         // It's protected access, check if stack object is assignable to
2213         // current class.
2214         is_assignable = current_type().is_assignable_from(
2215           stack_object_type, this, CHECK_VERIFY(this));
2216         if (!is_assignable) {
2217           verify_error(ErrorContext::bad_type(bci,
2218               current_frame->stack_top_ctx(),
2219               TypeOrigin::implicit(current_type())),
2220               "Bad access to protected data in getfield");
2221           return;
2222         }
2223       }
2224       break;
2225     }
2226     default: ShouldNotReachHere();
2227   }
2228 }
2229 
2230 void ClassVerifier::verify_invoke_init(
2231     RawBytecodeStream* bcs, u2 ref_class_index, VerificationType ref_class_type,
2232     StackMapFrame* current_frame, u4 code_length, bool *this_uninit,
2233     constantPoolHandle cp, TRAPS) {
2234   u2 bci = bcs->bci();
2235   VerificationType type = current_frame->pop_stack(
2236     VerificationType::reference_check(), CHECK_VERIFY(this));
2237   if (type == VerificationType::uninitialized_this_type()) {
2238     // The method must be an <init> method of this class or its superclass
2239     Klass* superk = current_class()->super();
2240     if (ref_class_type.name() != current_class()->name() &&
2241         ref_class_type.name() != superk->name()) {
2242       verify_error(ErrorContext::bad_type(bci,
2243           TypeOrigin::implicit(ref_class_type),
2244           TypeOrigin::implicit(current_type())),
2245           "Bad <init> method call");
2246       return;
2247     }
2248     current_frame->initialize_object(type, current_type());
2249     *this_uninit = true;
2250   } else if (type.is_uninitialized()) {
2251     u2 new_offset = type.bci();
2252     address new_bcp = bcs->bcp() - bci + new_offset;
2253     if (new_offset > (code_length - 3) || (*new_bcp) != Bytecodes::_new) {
2254       /* Unreachable?  Stack map parsing ensures valid type and new
2255        * instructions have a valid BCI. */
2256       verify_error(ErrorContext::bad_code(new_offset),
2257                    "Expecting new instruction");
2258       return;
2259     }
2260     u2 new_class_index = Bytes::get_Java_u2(new_bcp + 1);
2261     verify_cp_class_type(bci, new_class_index, cp, CHECK_VERIFY(this));
2262 
2263     // The method must be an <init> method of the indicated class
2264     VerificationType new_class_type = cp_index_to_type(
2265       new_class_index, cp, CHECK_VERIFY(this));
2266     if (!new_class_type.equals(ref_class_type)) {
2267       verify_error(ErrorContext::bad_type(bci,
2268           TypeOrigin::cp(new_class_index, new_class_type),
2269           TypeOrigin::cp(ref_class_index, ref_class_type)),
2270           "Call to wrong <init> method");
2271       return;
2272     }
2273     // According to the VM spec, if the referent class is a superclass of the
2274     // current class, and is in a different runtime package, and the method is
2275     // protected, then the objectref must be the current class or a subclass
2276     // of the current class.
2277     VerificationType objectref_type = new_class_type;
2278     if (name_in_supers(ref_class_type.name(), current_class())) {
2279       Klass* ref_klass = load_class(
2280         ref_class_type.name(), CHECK_VERIFY(this));
2281       Method* m = InstanceKlass::cast(ref_klass)->uncached_lookup_method(
2282         vmSymbols::object_initializer_name(),
2283         cp->signature_ref_at(bcs->get_index_u2()));
2284       instanceKlassHandle mh(THREAD, m->method_holder());
2285       if (m->is_protected() && !mh->is_same_class_package(_klass())) {
2286         bool assignable = current_type().is_assignable_from(
2287           objectref_type, this, CHECK_VERIFY(this));
2288         if (!assignable) {
2289           verify_error(ErrorContext::bad_type(bci,
2290               TypeOrigin::cp(new_class_index, objectref_type),
2291               TypeOrigin::implicit(current_type())),
2292               "Bad access to protected <init> method");
2293           return;
2294         }
2295       }
2296     }
2297     current_frame->initialize_object(type, new_class_type);
2298   } else {
2299     verify_error(ErrorContext::bad_type(bci, current_frame->stack_top_ctx()),
2300         "Bad operand type when invoking <init>");
2301     return;
2302   }
2303 }
2304 
2305 bool ClassVerifier::is_same_or_direct_interface(
2306     instanceKlassHandle klass,
2307     VerificationType klass_type,
2308     VerificationType ref_class_type) {
2309   if (ref_class_type.equals(klass_type)) return true;
2310   Array<Klass*>* local_interfaces = klass->local_interfaces();
2311   if (local_interfaces != NULL) {
2312     for (int x = 0; x < local_interfaces->length(); x++) {
2313       Klass* k = local_interfaces->at(x);
2314       assert (k != NULL && k->is_interface(), "invalid interface");
2315       if (ref_class_type.equals(VerificationType::reference_type(k->name()))) {
2316         return true;
2317       }
2318     }
2319   }
2320   return false;
2321 }
2322 
2323 void ClassVerifier::verify_invoke_instructions(
2324     RawBytecodeStream* bcs, u4 code_length, StackMapFrame* current_frame,
2325     bool *this_uninit, VerificationType return_type,
2326     constantPoolHandle cp, TRAPS) {
2327   // Make sure the constant pool item is the right type
2328   u2 index = bcs->get_index_u2();
2329   Bytecodes::Code opcode = bcs->raw_code();
2330   unsigned int types;
2331   switch (opcode) {
2332     case Bytecodes::_invokeinterface:
2333       types = 1 << JVM_CONSTANT_InterfaceMethodref;
2334       break;
2335     case Bytecodes::_invokedynamic:
2336       types = 1 << JVM_CONSTANT_InvokeDynamic;
2337       break;
2338     case Bytecodes::_invokespecial:
2339     case Bytecodes::_invokestatic:
2340       types = (_klass->major_version() < STATIC_METHOD_IN_INTERFACE_MAJOR_VERSION) ?
2341         (1 << JVM_CONSTANT_Methodref) :
2342         ((1 << JVM_CONSTANT_InterfaceMethodref) | (1 << JVM_CONSTANT_Methodref));
2343       break;
2344     default:
2345       types = 1 << JVM_CONSTANT_Methodref;
2346   }
2347   verify_cp_type(bcs->bci(), index, cp, types, CHECK_VERIFY(this));
2348 
2349   // Get method name and signature
2350   Symbol* method_name = cp->name_ref_at(index);
2351   Symbol* method_sig = cp->signature_ref_at(index);
2352 
2353   if (!SignatureVerifier::is_valid_method_signature(method_sig)) {
2354     class_format_error(
2355       "Invalid method signature in class %s referenced "
2356       "from constant pool index %d", _klass->external_name(), index);
2357     return;
2358   }
2359 
2360   // Get referenced class type
2361   VerificationType ref_class_type;
2362   if (opcode == Bytecodes::_invokedynamic) {
2363     if (!EnableInvokeDynamic ||
2364         _klass->major_version() < Verifier::INVOKEDYNAMIC_MAJOR_VERSION) {
2365       class_format_error(
2366         (!EnableInvokeDynamic ?
2367          "invokedynamic instructions not enabled in this JVM" :
2368          "invokedynamic instructions not supported by this class file version"),
2369         _klass->external_name());
2370       return;
2371     }
2372   } else {
2373     ref_class_type = cp_ref_index_to_type(index, cp, CHECK_VERIFY(this));
2374   }
2375 
2376   // For a small signature length, we just allocate 128 bytes instead
2377   // of parsing the signature once to find its size.
2378   // -3 is for '(', ')' and return descriptor; multiply by 2 is for
2379   // longs/doubles to be consertive.
2380   assert(sizeof(VerificationType) == sizeof(uintptr_t),
2381         "buffer type must match VerificationType size");
2382   uintptr_t on_stack_sig_types_buffer[128];
2383   // If we make a VerificationType[128] array directly, the compiler calls
2384   // to the c-runtime library to do the allocation instead of just
2385   // stack allocating it.  Plus it would run constructors.  This shows up
2386   // in performance profiles.
2387 
2388   VerificationType* sig_types;
2389   int size = (method_sig->utf8_length() - 3) * 2;
2390   if (size > 128) {
2391     // Long and double occupies two slots here.
2392     ArgumentSizeComputer size_it(method_sig);
2393     size = size_it.size();
2394     sig_types = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, VerificationType, size);
2395   } else{
2396     sig_types = (VerificationType*)on_stack_sig_types_buffer;
2397   }
2398   SignatureStream sig_stream(method_sig);
2399   int sig_i = 0;
2400   while (!sig_stream.at_return_type()) {
2401     sig_i += change_sig_to_verificationType(
2402       &sig_stream, &sig_types[sig_i], CHECK_VERIFY(this));
2403     sig_stream.next();
2404   }
2405   int nargs = sig_i;
2406 
2407 #ifdef ASSERT
2408   {
2409     ArgumentSizeComputer size_it(method_sig);
2410     assert(nargs == size_it.size(), "Argument sizes do not match");
2411     assert(nargs <= (method_sig->utf8_length() - 3) * 2, "estimate of max size isn't conservative enough");
2412   }
2413 #endif
2414 
2415   // Check instruction operands
2416   u2 bci = bcs->bci();
2417   if (opcode == Bytecodes::_invokeinterface) {
2418     address bcp = bcs->bcp();
2419     // 4905268: count operand in invokeinterface should be nargs+1, not nargs.
2420     // JSR202 spec: The count operand of an invokeinterface instruction is valid if it is
2421     // the difference between the size of the operand stack before and after the instruction
2422     // executes.
2423     if (*(bcp+3) != (nargs+1)) {
2424       verify_error(ErrorContext::bad_code(bci),
2425           "Inconsistent args count operand in invokeinterface");
2426       return;
2427     }
2428     if (*(bcp+4) != 0) {
2429       verify_error(ErrorContext::bad_code(bci),
2430           "Fourth operand byte of invokeinterface must be zero");
2431       return;
2432     }
2433   }
2434 
2435   if (opcode == Bytecodes::_invokedynamic) {
2436     address bcp = bcs->bcp();
2437     if (*(bcp+3) != 0 || *(bcp+4) != 0) {
2438       verify_error(ErrorContext::bad_code(bci),
2439           "Third and fourth operand bytes of invokedynamic must be zero");
2440       return;
2441     }
2442   }
2443 
2444   if (method_name->byte_at(0) == '<') {
2445     // Make sure <init> can only be invoked by invokespecial
2446     if (opcode != Bytecodes::_invokespecial ||
2447         method_name != vmSymbols::object_initializer_name()) {
2448       verify_error(ErrorContext::bad_code(bci),
2449           "Illegal call to internal method");
2450       return;
2451     }
2452   } else if (opcode == Bytecodes::_invokespecial
2453              && !is_same_or_direct_interface(current_class(), current_type(), ref_class_type)
2454              && !ref_class_type.equals(VerificationType::reference_type(
2455                   current_class()->super()->name()))) {
2456     bool subtype = false;
2457     bool same_or_direct = false;
2458     if (!current_class()->is_anonymous()) {
2459       subtype = ref_class_type.is_assignable_from(
2460                  current_type(), this, CHECK_VERIFY(this));
2461     } else {
2462       VerificationType host_klass_type =
2463                         VerificationType::reference_type(current_class()->host_klass()->name());
2464       subtype = ref_class_type.is_assignable_from(host_klass_type, this, CHECK_VERIFY(this));
2465       // Recheck for same or direct interface relevant to the host class
2466       same_or_direct = is_same_or_direct_interface(
2467                         InstanceKlass::cast(current_class()->host_klass()),
2468                         host_klass_type, ref_class_type);
2469     }
2470     if (!subtype) {
2471       verify_error(ErrorContext::bad_code(bci),
2472           "Bad invokespecial instruction: "
2473           "current class isn't assignable to reference class.");
2474        return;
2475     } else if (!same_or_direct &&
2476                cp->tag_at(index).value() == JVM_CONSTANT_InterfaceMethodref) {
2477       verify_error(ErrorContext::bad_code(bci),
2478           "Bad invokespecial instruction: "
2479           "interface method reference is in an indirect superinterface.");
2480       return;
2481     }
2482 
2483   }
2484   // Match method descriptor with operand stack
2485   for (int i = nargs - 1; i >= 0; i--) {  // Run backwards
2486     current_frame->pop_stack(sig_types[i], CHECK_VERIFY(this));
2487   }
2488   // Check objectref on operand stack
2489   if (opcode != Bytecodes::_invokestatic &&
2490       opcode != Bytecodes::_invokedynamic) {
2491     if (method_name == vmSymbols::object_initializer_name()) {  // <init> method
2492       verify_invoke_init(bcs, index, ref_class_type, current_frame,
2493         code_length, this_uninit, cp, CHECK_VERIFY(this));
2494     } else {   // other methods
2495       // Ensures that target class is assignable to method class.
2496       if (opcode == Bytecodes::_invokespecial) {
2497         if (!current_class()->is_anonymous()) {
2498           current_frame->pop_stack(current_type(), CHECK_VERIFY(this));
2499         } else {
2500           // anonymous class invokespecial calls: check if the
2501           // objectref is a subtype of the host_klass of the current class
2502           // to allow an anonymous class to reference methods in the host_klass
2503           VerificationType top = current_frame->pop_stack(CHECK_VERIFY(this));
2504           VerificationType hosttype =
2505             VerificationType::reference_type(current_class()->host_klass()->name());
2506           bool subtype = hosttype.is_assignable_from(top, this, CHECK_VERIFY(this));
2507           if (!subtype) {
2508             verify_error( ErrorContext::bad_type(current_frame->offset(),
2509               current_frame->stack_top_ctx(),
2510               TypeOrigin::implicit(top)),
2511               "Bad type on operand stack");
2512             return;
2513           }
2514         }
2515       } else if (opcode == Bytecodes::_invokevirtual) {
2516         VerificationType stack_object_type =
2517           current_frame->pop_stack(ref_class_type, CHECK_VERIFY(this));
2518         if (current_type() != stack_object_type) {
2519           assert(cp->cache() == NULL, "not rewritten yet");
2520           Symbol* ref_class_name =
2521             cp->klass_name_at(cp->klass_ref_index_at(index));
2522           // See the comments in verify_field_instructions() for
2523           // the rationale behind this.
2524           if (name_in_supers(ref_class_name, current_class())) {
2525             Klass* ref_class = load_class(ref_class_name, CHECK);
2526             if (is_protected_access(
2527                   _klass, ref_class, method_name, method_sig, true)) {
2528               // It's protected access, check if stack object is
2529               // assignable to current class.
2530               bool is_assignable = current_type().is_assignable_from(
2531                 stack_object_type, this, CHECK_VERIFY(this));
2532               if (!is_assignable) {
2533                 if (ref_class_type.name() == vmSymbols::java_lang_Object()
2534                     && stack_object_type.is_array()
2535                     && method_name == vmSymbols::clone_name()) {
2536                   // Special case: arrays pretend to implement public Object
2537                   // clone().
2538                 } else {
2539                   verify_error(ErrorContext::bad_type(bci,
2540                       current_frame->stack_top_ctx(),
2541                       TypeOrigin::implicit(current_type())),
2542                       "Bad access to protected data in invokevirtual");
2543                   return;
2544                 }
2545               }
2546             }
2547           }
2548         }
2549       } else {
2550         assert(opcode == Bytecodes::_invokeinterface, "Unexpected opcode encountered");
2551         current_frame->pop_stack(ref_class_type, CHECK_VERIFY(this));
2552       }
2553     }
2554   }
2555   // Push the result type.
2556   if (sig_stream.type() != T_VOID) {
2557     if (method_name == vmSymbols::object_initializer_name()) {
2558       // <init> method must have a void return type
2559       /* Unreachable?  Class file parser verifies that methods with '<' have
2560        * void return */
2561       verify_error(ErrorContext::bad_code(bci),
2562           "Return type must be void in <init> method");
2563       return;
2564     }
2565     VerificationType return_type[2];
2566     int n = change_sig_to_verificationType(
2567       &sig_stream, return_type, CHECK_VERIFY(this));
2568     for (int i = 0; i < n; i++) {
2569       current_frame->push_stack(return_type[i], CHECK_VERIFY(this)); // push types backwards
2570     }
2571   }
2572 }
2573 
2574 VerificationType ClassVerifier::get_newarray_type(
2575     u2 index, u2 bci, TRAPS) {
2576   const char* from_bt[] = {
2577     NULL, NULL, NULL, NULL, "[Z", "[C", "[F", "[D", "[B", "[S", "[I", "[J",
2578   };
2579   if (index < T_BOOLEAN || index > T_LONG) {
2580     verify_error(ErrorContext::bad_code(bci), "Illegal newarray instruction");
2581     return VerificationType::bogus_type();
2582   }
2583 
2584   // from_bt[index] contains the array signature which has a length of 2
2585   Symbol* sig = create_temporary_symbol(
2586     from_bt[index], 2, CHECK_(VerificationType::bogus_type()));
2587   return VerificationType::reference_type(sig);
2588 }
2589 
2590 void ClassVerifier::verify_anewarray(
2591     u2 bci, u2 index, constantPoolHandle cp,
2592     StackMapFrame* current_frame, TRAPS) {
2593   verify_cp_class_type(bci, index, cp, CHECK_VERIFY(this));
2594   current_frame->pop_stack(
2595     VerificationType::integer_type(), CHECK_VERIFY(this));
2596 
2597   VerificationType component_type =
2598     cp_index_to_type(index, cp, CHECK_VERIFY(this));
2599   int length;
2600   char* arr_sig_str;
2601   if (component_type.is_array()) {     // it's an array
2602     const char* component_name = component_type.name()->as_utf8();
2603     // add one dimension to component
2604     length = (int)strlen(component_name) + 1;
2605     arr_sig_str = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, length);
2606     arr_sig_str[0] = '[';
2607     strncpy(&arr_sig_str[1], component_name, length - 1);
2608   } else {         // it's an object or interface
2609     const char* component_name = component_type.name()->as_utf8();
2610     // add one dimension to component with 'L' prepended and ';' postpended.
2611     length = (int)strlen(component_name) + 3;
2612     arr_sig_str = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, length);
2613     arr_sig_str[0] = '[';
2614     arr_sig_str[1] = 'L';
2615     strncpy(&arr_sig_str[2], component_name, length - 2);
2616     arr_sig_str[length - 1] = ';';
2617   }
2618   Symbol* arr_sig = create_temporary_symbol(
2619     arr_sig_str, length, CHECK_VERIFY(this));
2620   VerificationType new_array_type = VerificationType::reference_type(arr_sig);
2621   current_frame->push_stack(new_array_type, CHECK_VERIFY(this));
2622 }
2623 
2624 void ClassVerifier::verify_iload(u2 index, StackMapFrame* current_frame, TRAPS) {
2625   current_frame->get_local(
2626     index, VerificationType::integer_type(), CHECK_VERIFY(this));
2627   current_frame->push_stack(
2628     VerificationType::integer_type(), CHECK_VERIFY(this));
2629 }
2630 
2631 void ClassVerifier::verify_lload(u2 index, StackMapFrame* current_frame, TRAPS) {
2632   current_frame->get_local_2(
2633     index, VerificationType::long_type(),
2634     VerificationType::long2_type(), CHECK_VERIFY(this));
2635   current_frame->push_stack_2(
2636     VerificationType::long_type(),
2637     VerificationType::long2_type(), CHECK_VERIFY(this));
2638 }
2639 
2640 void ClassVerifier::verify_fload(u2 index, StackMapFrame* current_frame, TRAPS) {
2641   current_frame->get_local(
2642     index, VerificationType::float_type(), CHECK_VERIFY(this));
2643   current_frame->push_stack(
2644     VerificationType::float_type(), CHECK_VERIFY(this));
2645 }
2646 
2647 void ClassVerifier::verify_dload(u2 index, StackMapFrame* current_frame, TRAPS) {
2648   current_frame->get_local_2(
2649     index, VerificationType::double_type(),
2650     VerificationType::double2_type(), CHECK_VERIFY(this));
2651   current_frame->push_stack_2(
2652     VerificationType::double_type(),
2653     VerificationType::double2_type(), CHECK_VERIFY(this));
2654 }
2655 
2656 void ClassVerifier::verify_aload(u2 index, StackMapFrame* current_frame, TRAPS) {
2657   VerificationType type = current_frame->get_local(
2658     index, VerificationType::reference_check(), CHECK_VERIFY(this));
2659   current_frame->push_stack(type, CHECK_VERIFY(this));
2660 }
2661 
2662 void ClassVerifier::verify_istore(u2 index, StackMapFrame* current_frame, TRAPS) {
2663   current_frame->pop_stack(
2664     VerificationType::integer_type(), CHECK_VERIFY(this));
2665   current_frame->set_local(
2666     index, VerificationType::integer_type(), CHECK_VERIFY(this));
2667 }
2668 
2669 void ClassVerifier::verify_lstore(u2 index, StackMapFrame* current_frame, TRAPS) {
2670   current_frame->pop_stack_2(
2671     VerificationType::long2_type(),
2672     VerificationType::long_type(), CHECK_VERIFY(this));
2673   current_frame->set_local_2(
2674     index, VerificationType::long_type(),
2675     VerificationType::long2_type(), CHECK_VERIFY(this));
2676 }
2677 
2678 void ClassVerifier::verify_fstore(u2 index, StackMapFrame* current_frame, TRAPS) {
2679   current_frame->pop_stack(VerificationType::float_type(), CHECK_VERIFY(this));
2680   current_frame->set_local(
2681     index, VerificationType::float_type(), CHECK_VERIFY(this));
2682 }
2683 
2684 void ClassVerifier::verify_dstore(u2 index, StackMapFrame* current_frame, TRAPS) {
2685   current_frame->pop_stack_2(
2686     VerificationType::double2_type(),
2687     VerificationType::double_type(), CHECK_VERIFY(this));
2688   current_frame->set_local_2(
2689     index, VerificationType::double_type(),
2690     VerificationType::double2_type(), CHECK_VERIFY(this));
2691 }
2692 
2693 void ClassVerifier::verify_astore(u2 index, StackMapFrame* current_frame, TRAPS) {
2694   VerificationType type = current_frame->pop_stack(
2695     VerificationType::reference_check(), CHECK_VERIFY(this));
2696   current_frame->set_local(index, type, CHECK_VERIFY(this));
2697 }
2698 
2699 void ClassVerifier::verify_iinc(u2 index, StackMapFrame* current_frame, TRAPS) {
2700   VerificationType type = current_frame->get_local(
2701     index, VerificationType::integer_type(), CHECK_VERIFY(this));
2702   current_frame->set_local(index, type, CHECK_VERIFY(this));
2703 }
2704 
2705 void ClassVerifier::verify_return_value(
2706     VerificationType return_type, VerificationType type, u2 bci,
2707     StackMapFrame* current_frame, TRAPS) {
2708   if (return_type == VerificationType::bogus_type()) {
2709     verify_error(ErrorContext::bad_type(bci,
2710         current_frame->stack_top_ctx(), TypeOrigin::signature(return_type)),
2711         "Method expects a return value");
2712     return;
2713   }
2714   bool match = return_type.is_assignable_from(type, this, CHECK_VERIFY(this));
2715   if (!match) {
2716     verify_error(ErrorContext::bad_type(bci,
2717         current_frame->stack_top_ctx(), TypeOrigin::signature(return_type)),
2718         "Bad return type");
2719     return;
2720   }
2721 }
2722 
2723 // The verifier creates symbols which are substrings of Symbols.
2724 // These are stored in the verifier until the end of verification so that
2725 // they can be reference counted.
2726 Symbol* ClassVerifier::create_temporary_symbol(const Symbol *s, int begin,
2727                                                int end, TRAPS) {
2728   Symbol* sym = SymbolTable::new_symbol(s, begin, end, CHECK_NULL);
2729   _symbols->push(sym);
2730   return sym;
2731 }
2732 
2733 Symbol* ClassVerifier::create_temporary_symbol(const char *s, int length, TRAPS) {
2734   Symbol* sym = SymbolTable::new_symbol(s, length, CHECK_NULL);
2735   _symbols->push(sym);
2736   return sym;
2737 }