void ClassVerifier::verify_method()

in src/hotspot/src/share/vm/classfile/verifier.cpp [583:1704]


void ClassVerifier::verify_method(methodHandle m, TRAPS) {
  HandleMark hm(THREAD);
  _method = m;   // initialize _method
  if (VerboseVerification) {
    tty->print_cr("Verifying method %s", m->name_and_sig_as_C_string());
  }

// For clang, the only good constant format string is a literal constant format string.
#define bad_type_msg "Bad type on operand stack in %s"

  int32_t max_stack = m->verifier_max_stack();
  int32_t max_locals = m->max_locals();
  constantPoolHandle cp(THREAD, m->constants());

  if (!SignatureVerifier::is_valid_method_signature(m->signature())) {
    class_format_error("Invalid method signature");
    return;
  }

  // Initial stack map frame: offset is 0, stack is initially empty.
  StackMapFrame current_frame(max_locals, max_stack, this);
  // Set initial locals
  VerificationType return_type = current_frame.set_locals_from_arg(
    m, current_type(), CHECK_VERIFY(this));

  int32_t stackmap_index = 0; // index to the stackmap array

  u4 code_length = m->code_size();

  // Scan the bytecode and map each instruction's start offset to a number.
  char* code_data = generate_code_data(m, code_length, CHECK_VERIFY(this));

  int ex_min = code_length;
  int ex_max = -1;
  // Look through each item on the exception table. Each of the fields must refer
  // to a legal instruction.
  verify_exception_handler_table(
    code_length, code_data, ex_min, ex_max, CHECK_VERIFY(this));

  // Look through each entry on the local variable table and make sure
  // its range of code array offsets is valid. (4169817)
  if (m->has_localvariable_table()) {
    verify_local_variable_table(code_length, code_data, CHECK_VERIFY(this));
  }

  Array<u1>* stackmap_data = m->stackmap_data();
  StackMapStream stream(stackmap_data);
  StackMapReader reader(this, &stream, code_data, code_length, THREAD);
  StackMapTable stackmap_table(&reader, &current_frame, max_locals, max_stack,
                               code_data, code_length, CHECK_VERIFY(this));

  if (VerboseVerification) {
    stackmap_table.print_on(tty);
  }

  RawBytecodeStream bcs(m);

  // Scan the byte code linearly from the start to the end
  bool no_control_flow = false; // Set to true when there is no direct control
                                // flow from current instruction to the next
                                // instruction in sequence

  Bytecodes::Code opcode;
  while (!bcs.is_last_bytecode()) {
    // Check for recursive re-verification before each bytecode.
    if (was_recursively_verified())  return;

    opcode = bcs.raw_next();
    u2 bci = bcs.bci();

    // Set current frame's offset to bci
    current_frame.set_offset(bci);
    current_frame.set_mark();

    // Make sure every offset in stackmap table point to the beginning to
    // an instruction. Match current_frame to stackmap_table entry with
    // the same offset if exists.
    stackmap_index = verify_stackmap_table(
      stackmap_index, bci, &current_frame, &stackmap_table,
      no_control_flow, CHECK_VERIFY(this));


    bool this_uninit = false;  // Set to true when invokespecial <init> initialized 'this'
    bool verified_exc_handlers = false;

    // Merge with the next instruction
    {
      u2 index;
      int target;
      VerificationType type, type2;
      VerificationType atype;

#ifndef PRODUCT
      if (VerboseVerification) {
        current_frame.print_on(tty);
        tty->print_cr("offset = %d,  opcode = %s", bci, Bytecodes::name(opcode));
      }
#endif

      // Make sure wide instruction is in correct format
      if (bcs.is_wide()) {
        if (opcode != Bytecodes::_iinc   && opcode != Bytecodes::_iload  &&
            opcode != Bytecodes::_aload  && opcode != Bytecodes::_lload  &&
            opcode != Bytecodes::_istore && opcode != Bytecodes::_astore &&
            opcode != Bytecodes::_lstore && opcode != Bytecodes::_fload  &&
            opcode != Bytecodes::_dload  && opcode != Bytecodes::_fstore &&
            opcode != Bytecodes::_dstore) {
          /* Unreachable?  RawBytecodeStream's raw_next() returns 'illegal'
           * if we encounter a wide instruction that modifies an invalid
           * opcode (not one of the ones listed above) */
          verify_error(ErrorContext::bad_code(bci), "Bad wide instruction");
          return;
        }
      }

      // Look for possible jump target in exception handlers and see if it
      // matches current_frame.  Do this check here for astore*, dstore*,
      // fstore*, istore*, and lstore* opcodes because they can change the type
      // state by adding a local.  JVM Spec says that the incoming type state
      // should be used for this check.  So, do the check here before a possible
      // local is added to the type state.
      if (Bytecodes::is_store_into_local(opcode) && bci >= ex_min && bci < ex_max) {
        verify_exception_handler_targets(
          bci, this_uninit, &current_frame, &stackmap_table, CHECK_VERIFY(this));
        verified_exc_handlers = true;
      }

      switch (opcode) {
        case Bytecodes::_nop :
          no_control_flow = false; break;
        case Bytecodes::_aconst_null :
          current_frame.push_stack(
            VerificationType::null_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_iconst_m1 :
        case Bytecodes::_iconst_0 :
        case Bytecodes::_iconst_1 :
        case Bytecodes::_iconst_2 :
        case Bytecodes::_iconst_3 :
        case Bytecodes::_iconst_4 :
        case Bytecodes::_iconst_5 :
          current_frame.push_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_lconst_0 :
        case Bytecodes::_lconst_1 :
          current_frame.push_stack_2(
            VerificationType::long_type(),
            VerificationType::long2_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_fconst_0 :
        case Bytecodes::_fconst_1 :
        case Bytecodes::_fconst_2 :
          current_frame.push_stack(
            VerificationType::float_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_dconst_0 :
        case Bytecodes::_dconst_1 :
          current_frame.push_stack_2(
            VerificationType::double_type(),
            VerificationType::double2_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_sipush :
        case Bytecodes::_bipush :
          current_frame.push_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_ldc :
          verify_ldc(
            opcode, bcs.get_index_u1(), &current_frame,
            cp, bci, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_ldc_w :
        case Bytecodes::_ldc2_w :
          verify_ldc(
            opcode, bcs.get_index_u2(), &current_frame,
            cp, bci, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_iload :
          verify_iload(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_iload_0 :
        case Bytecodes::_iload_1 :
        case Bytecodes::_iload_2 :
        case Bytecodes::_iload_3 :
          index = opcode - Bytecodes::_iload_0;
          verify_iload(index, &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_lload :
          verify_lload(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_lload_0 :
        case Bytecodes::_lload_1 :
        case Bytecodes::_lload_2 :
        case Bytecodes::_lload_3 :
          index = opcode - Bytecodes::_lload_0;
          verify_lload(index, &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_fload :
          verify_fload(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_fload_0 :
        case Bytecodes::_fload_1 :
        case Bytecodes::_fload_2 :
        case Bytecodes::_fload_3 :
          index = opcode - Bytecodes::_fload_0;
          verify_fload(index, &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_dload :
          verify_dload(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_dload_0 :
        case Bytecodes::_dload_1 :
        case Bytecodes::_dload_2 :
        case Bytecodes::_dload_3 :
          index = opcode - Bytecodes::_dload_0;
          verify_dload(index, &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_aload :
          verify_aload(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_aload_0 :
        case Bytecodes::_aload_1 :
        case Bytecodes::_aload_2 :
        case Bytecodes::_aload_3 :
          index = opcode - Bytecodes::_aload_0;
          verify_aload(index, &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_iaload :
          type = current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          atype = current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          if (!atype.is_int_array()) {
            verify_error(ErrorContext::bad_type(bci,
                current_frame.stack_top_ctx(), ref_ctx("[I", THREAD)),
                bad_type_msg, "iaload");
            return;
          }
          current_frame.push_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_baload :
          type = current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          atype = current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          if (!atype.is_bool_array() && !atype.is_byte_array()) {
            verify_error(
                ErrorContext::bad_type(bci, current_frame.stack_top_ctx()),
                bad_type_msg, "baload");
            return;
          }
          current_frame.push_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_caload :
          type = current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          atype = current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          if (!atype.is_char_array()) {
            verify_error(ErrorContext::bad_type(bci,
                current_frame.stack_top_ctx(), ref_ctx("[C", THREAD)),
                bad_type_msg, "caload");
            return;
          }
          current_frame.push_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_saload :
          type = current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          atype = current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          if (!atype.is_short_array()) {
            verify_error(ErrorContext::bad_type(bci,
                current_frame.stack_top_ctx(), ref_ctx("[S", THREAD)),
                bad_type_msg, "saload");
            return;
          }
          current_frame.push_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_laload :
          type = current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          atype = current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          if (!atype.is_long_array()) {
            verify_error(ErrorContext::bad_type(bci,
                current_frame.stack_top_ctx(), ref_ctx("[J", THREAD)),
                bad_type_msg, "laload");
            return;
          }
          current_frame.push_stack_2(
            VerificationType::long_type(),
            VerificationType::long2_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_faload :
          type = current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          atype = current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          if (!atype.is_float_array()) {
            verify_error(ErrorContext::bad_type(bci,
                current_frame.stack_top_ctx(), ref_ctx("[F", THREAD)),
                bad_type_msg, "faload");
            return;
          }
          current_frame.push_stack(
            VerificationType::float_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_daload :
          type = current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          atype = current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          if (!atype.is_double_array()) {
            verify_error(ErrorContext::bad_type(bci,
                current_frame.stack_top_ctx(), ref_ctx("[D", THREAD)),
                bad_type_msg, "daload");
            return;
          }
          current_frame.push_stack_2(
            VerificationType::double_type(),
            VerificationType::double2_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_aaload : {
          type = current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          atype = current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          if (!atype.is_reference_array()) {
            verify_error(ErrorContext::bad_type(bci,
                current_frame.stack_top_ctx(),
                TypeOrigin::implicit(VerificationType::reference_check())),
                bad_type_msg, "aaload");
            return;
          }
          if (atype.is_null()) {
            current_frame.push_stack(
              VerificationType::null_type(), CHECK_VERIFY(this));
          } else {
            VerificationType component =
              atype.get_component(this, CHECK_VERIFY(this));
            current_frame.push_stack(component, CHECK_VERIFY(this));
          }
          no_control_flow = false; break;
        }
        case Bytecodes::_istore :
          verify_istore(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_istore_0 :
        case Bytecodes::_istore_1 :
        case Bytecodes::_istore_2 :
        case Bytecodes::_istore_3 :
          index = opcode - Bytecodes::_istore_0;
          verify_istore(index, &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_lstore :
          verify_lstore(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_lstore_0 :
        case Bytecodes::_lstore_1 :
        case Bytecodes::_lstore_2 :
        case Bytecodes::_lstore_3 :
          index = opcode - Bytecodes::_lstore_0;
          verify_lstore(index, &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_fstore :
          verify_fstore(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_fstore_0 :
        case Bytecodes::_fstore_1 :
        case Bytecodes::_fstore_2 :
        case Bytecodes::_fstore_3 :
          index = opcode - Bytecodes::_fstore_0;
          verify_fstore(index, &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_dstore :
          verify_dstore(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_dstore_0 :
        case Bytecodes::_dstore_1 :
        case Bytecodes::_dstore_2 :
        case Bytecodes::_dstore_3 :
          index = opcode - Bytecodes::_dstore_0;
          verify_dstore(index, &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_astore :
          verify_astore(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_astore_0 :
        case Bytecodes::_astore_1 :
        case Bytecodes::_astore_2 :
        case Bytecodes::_astore_3 :
          index = opcode - Bytecodes::_astore_0;
          verify_astore(index, &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_iastore :
          type = current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          type2 = current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          atype = current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          if (!atype.is_int_array()) {
            verify_error(ErrorContext::bad_type(bci,
                current_frame.stack_top_ctx(), ref_ctx("[I", THREAD)),
                bad_type_msg, "iastore");
            return;
          }
          no_control_flow = false; break;
        case Bytecodes::_bastore :
          type = current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          type2 = current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          atype = current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          if (!atype.is_bool_array() && !atype.is_byte_array()) {
            verify_error(
                ErrorContext::bad_type(bci, current_frame.stack_top_ctx()),
                bad_type_msg, "bastore");
            return;
          }
          no_control_flow = false; break;
        case Bytecodes::_castore :
          current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          atype = current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          if (!atype.is_char_array()) {
            verify_error(ErrorContext::bad_type(bci,
                current_frame.stack_top_ctx(), ref_ctx("[C", THREAD)),
                bad_type_msg, "castore");
            return;
          }
          no_control_flow = false; break;
        case Bytecodes::_sastore :
          current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          atype = current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          if (!atype.is_short_array()) {
            verify_error(ErrorContext::bad_type(bci,
                current_frame.stack_top_ctx(), ref_ctx("[S", THREAD)),
                bad_type_msg, "sastore");
            return;
          }
          no_control_flow = false; break;
        case Bytecodes::_lastore :
          current_frame.pop_stack_2(
            VerificationType::long2_type(),
            VerificationType::long_type(), CHECK_VERIFY(this));
          current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          atype = current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          if (!atype.is_long_array()) {
            verify_error(ErrorContext::bad_type(bci,
                current_frame.stack_top_ctx(), ref_ctx("[J", THREAD)),
                bad_type_msg, "lastore");
            return;
          }
          no_control_flow = false; break;
        case Bytecodes::_fastore :
          current_frame.pop_stack(
            VerificationType::float_type(), CHECK_VERIFY(this));
          current_frame.pop_stack
            (VerificationType::integer_type(), CHECK_VERIFY(this));
          atype = current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          if (!atype.is_float_array()) {
            verify_error(ErrorContext::bad_type(bci,
                current_frame.stack_top_ctx(), ref_ctx("[F", THREAD)),
                bad_type_msg, "fastore");
            return;
          }
          no_control_flow = false; break;
        case Bytecodes::_dastore :
          current_frame.pop_stack_2(
            VerificationType::double2_type(),
            VerificationType::double_type(), CHECK_VERIFY(this));
          current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          atype = current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          if (!atype.is_double_array()) {
            verify_error(ErrorContext::bad_type(bci,
                current_frame.stack_top_ctx(), ref_ctx("[D", THREAD)),
                bad_type_msg, "dastore");
            return;
          }
          no_control_flow = false; break;
        case Bytecodes::_aastore :
          type = current_frame.pop_stack(object_type(), CHECK_VERIFY(this));
          type2 = current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          atype = current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          // more type-checking is done at runtime
          if (!atype.is_reference_array()) {
            verify_error(ErrorContext::bad_type(bci,
                current_frame.stack_top_ctx(),
                TypeOrigin::implicit(VerificationType::reference_check())),
                bad_type_msg, "aastore");
            return;
          }
          // 4938384: relaxed constraint in JVMS 3nd edition.
          no_control_flow = false; break;
        case Bytecodes::_pop :
          current_frame.pop_stack(
            VerificationType::category1_check(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_pop2 :
          type = current_frame.pop_stack(CHECK_VERIFY(this));
          if (type.is_category1()) {
            current_frame.pop_stack(
              VerificationType::category1_check(), CHECK_VERIFY(this));
          } else if (type.is_category2_2nd()) {
            current_frame.pop_stack(
              VerificationType::category2_check(), CHECK_VERIFY(this));
          } else {
            /* Unreachable? Would need a category2_1st on TOS
             * which does not appear possible. */
            verify_error(
                ErrorContext::bad_type(bci, current_frame.stack_top_ctx()),
                bad_type_msg, "pop2");
            return;
          }
          no_control_flow = false; break;
        case Bytecodes::_dup :
          type = current_frame.pop_stack(
            VerificationType::category1_check(), CHECK_VERIFY(this));
          current_frame.push_stack(type, CHECK_VERIFY(this));
          current_frame.push_stack(type, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_dup_x1 :
          type = current_frame.pop_stack(
            VerificationType::category1_check(), CHECK_VERIFY(this));
          type2 = current_frame.pop_stack(
            VerificationType::category1_check(), CHECK_VERIFY(this));
          current_frame.push_stack(type, CHECK_VERIFY(this));
          current_frame.push_stack(type2, CHECK_VERIFY(this));
          current_frame.push_stack(type, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_dup_x2 :
        {
          VerificationType type3;
          type = current_frame.pop_stack(
            VerificationType::category1_check(), CHECK_VERIFY(this));
          type2 = current_frame.pop_stack(CHECK_VERIFY(this));
          if (type2.is_category1()) {
            type3 = current_frame.pop_stack(
              VerificationType::category1_check(), CHECK_VERIFY(this));
          } else if (type2.is_category2_2nd()) {
            type3 = current_frame.pop_stack(
              VerificationType::category2_check(), CHECK_VERIFY(this));
          } else {
            /* Unreachable? Would need a category2_1st at stack depth 2 with
             * a category1 on TOS which does not appear possible. */
            verify_error(ErrorContext::bad_type(
                bci, current_frame.stack_top_ctx()), bad_type_msg, "dup_x2");
            return;
          }
          current_frame.push_stack(type, CHECK_VERIFY(this));
          current_frame.push_stack(type3, CHECK_VERIFY(this));
          current_frame.push_stack(type2, CHECK_VERIFY(this));
          current_frame.push_stack(type, CHECK_VERIFY(this));
          no_control_flow = false; break;
        }
        case Bytecodes::_dup2 :
          type = current_frame.pop_stack(CHECK_VERIFY(this));
          if (type.is_category1()) {
            type2 = current_frame.pop_stack(
              VerificationType::category1_check(), CHECK_VERIFY(this));
          } else if (type.is_category2_2nd()) {
            type2 = current_frame.pop_stack(
              VerificationType::category2_check(), CHECK_VERIFY(this));
          } else {
            /* Unreachable?  Would need a category2_1st on TOS which does not
             * appear possible. */
            verify_error(
                ErrorContext::bad_type(bci, current_frame.stack_top_ctx()),
                bad_type_msg, "dup2");
            return;
          }
          current_frame.push_stack(type2, CHECK_VERIFY(this));
          current_frame.push_stack(type, CHECK_VERIFY(this));
          current_frame.push_stack(type2, CHECK_VERIFY(this));
          current_frame.push_stack(type, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_dup2_x1 :
        {
          VerificationType type3;
          type = current_frame.pop_stack(CHECK_VERIFY(this));
          if (type.is_category1()) {
            type2 = current_frame.pop_stack(
              VerificationType::category1_check(), CHECK_VERIFY(this));
          } else if (type.is_category2_2nd()) {
            type2 = current_frame.pop_stack(
              VerificationType::category2_check(), CHECK_VERIFY(this));
          } else {
            /* Unreachable?  Would need a category2_1st on TOS which does
             * not appear possible. */
            verify_error(
                ErrorContext::bad_type(bci, current_frame.stack_top_ctx()),
                bad_type_msg, "dup2_x1");
            return;
          }
          type3 = current_frame.pop_stack(
            VerificationType::category1_check(), CHECK_VERIFY(this));
          current_frame.push_stack(type2, CHECK_VERIFY(this));
          current_frame.push_stack(type, CHECK_VERIFY(this));
          current_frame.push_stack(type3, CHECK_VERIFY(this));
          current_frame.push_stack(type2, CHECK_VERIFY(this));
          current_frame.push_stack(type, CHECK_VERIFY(this));
          no_control_flow = false; break;
        }
        case Bytecodes::_dup2_x2 :
        {
          VerificationType type3, type4;
          type = current_frame.pop_stack(CHECK_VERIFY(this));
          if (type.is_category1()) {
            type2 = current_frame.pop_stack(
              VerificationType::category1_check(), CHECK_VERIFY(this));
          } else if (type.is_category2_2nd()) {
            type2 = current_frame.pop_stack(
              VerificationType::category2_check(), CHECK_VERIFY(this));
          } else {
            /* Unreachable?  Would need a category2_1st on TOS which does
             * not appear possible. */
            verify_error(
                ErrorContext::bad_type(bci, current_frame.stack_top_ctx()),
                bad_type_msg, "dup2_x2");
            return;
          }
          type3 = current_frame.pop_stack(CHECK_VERIFY(this));
          if (type3.is_category1()) {
            type4 = current_frame.pop_stack(
              VerificationType::category1_check(), CHECK_VERIFY(this));
          } else if (type3.is_category2_2nd()) {
            type4 = current_frame.pop_stack(
              VerificationType::category2_check(), CHECK_VERIFY(this));
          } else {
            /* Unreachable?  Would need a category2_1st on TOS after popping
             * a long/double or two category 1's, which does not
             * appear possible. */
            verify_error(
                ErrorContext::bad_type(bci, current_frame.stack_top_ctx()),
                bad_type_msg, "dup2_x2");
            return;
          }
          current_frame.push_stack(type2, CHECK_VERIFY(this));
          current_frame.push_stack(type, CHECK_VERIFY(this));
          current_frame.push_stack(type4, CHECK_VERIFY(this));
          current_frame.push_stack(type3, CHECK_VERIFY(this));
          current_frame.push_stack(type2, CHECK_VERIFY(this));
          current_frame.push_stack(type, CHECK_VERIFY(this));
          no_control_flow = false; break;
        }
        case Bytecodes::_swap :
          type = current_frame.pop_stack(
            VerificationType::category1_check(), CHECK_VERIFY(this));
          type2 = current_frame.pop_stack(
            VerificationType::category1_check(), CHECK_VERIFY(this));
          current_frame.push_stack(type, CHECK_VERIFY(this));
          current_frame.push_stack(type2, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_iadd :
        case Bytecodes::_isub :
        case Bytecodes::_imul :
        case Bytecodes::_idiv :
        case Bytecodes::_irem :
        case Bytecodes::_ishl :
        case Bytecodes::_ishr :
        case Bytecodes::_iushr :
        case Bytecodes::_ior :
        case Bytecodes::_ixor :
        case Bytecodes::_iand :
          current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          // fall through
        case Bytecodes::_ineg :
          current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          current_frame.push_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_ladd :
        case Bytecodes::_lsub :
        case Bytecodes::_lmul :
        case Bytecodes::_ldiv :
        case Bytecodes::_lrem :
        case Bytecodes::_land :
        case Bytecodes::_lor :
        case Bytecodes::_lxor :
          current_frame.pop_stack_2(
            VerificationType::long2_type(),
            VerificationType::long_type(), CHECK_VERIFY(this));
          // fall through
        case Bytecodes::_lneg :
          current_frame.pop_stack_2(
            VerificationType::long2_type(),
            VerificationType::long_type(), CHECK_VERIFY(this));
          current_frame.push_stack_2(
            VerificationType::long_type(),
            VerificationType::long2_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_lshl :
        case Bytecodes::_lshr :
        case Bytecodes::_lushr :
          current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          current_frame.pop_stack_2(
            VerificationType::long2_type(),
            VerificationType::long_type(), CHECK_VERIFY(this));
          current_frame.push_stack_2(
            VerificationType::long_type(),
            VerificationType::long2_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_fadd :
        case Bytecodes::_fsub :
        case Bytecodes::_fmul :
        case Bytecodes::_fdiv :
        case Bytecodes::_frem :
          current_frame.pop_stack(
            VerificationType::float_type(), CHECK_VERIFY(this));
          // fall through
        case Bytecodes::_fneg :
          current_frame.pop_stack(
            VerificationType::float_type(), CHECK_VERIFY(this));
          current_frame.push_stack(
            VerificationType::float_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_dadd :
        case Bytecodes::_dsub :
        case Bytecodes::_dmul :
        case Bytecodes::_ddiv :
        case Bytecodes::_drem :
          current_frame.pop_stack_2(
            VerificationType::double2_type(),
            VerificationType::double_type(), CHECK_VERIFY(this));
          // fall through
        case Bytecodes::_dneg :
          current_frame.pop_stack_2(
            VerificationType::double2_type(),
            VerificationType::double_type(), CHECK_VERIFY(this));
          current_frame.push_stack_2(
            VerificationType::double_type(),
            VerificationType::double2_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_iinc :
          verify_iinc(bcs.get_index(), &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_i2l :
          type = current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          current_frame.push_stack_2(
            VerificationType::long_type(),
            VerificationType::long2_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
       case Bytecodes::_l2i :
          current_frame.pop_stack_2(
            VerificationType::long2_type(),
            VerificationType::long_type(), CHECK_VERIFY(this));
          current_frame.push_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_i2f :
          current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          current_frame.push_stack(
            VerificationType::float_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_i2d :
          current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          current_frame.push_stack_2(
            VerificationType::double_type(),
            VerificationType::double2_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_l2f :
          current_frame.pop_stack_2(
            VerificationType::long2_type(),
            VerificationType::long_type(), CHECK_VERIFY(this));
          current_frame.push_stack(
            VerificationType::float_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_l2d :
          current_frame.pop_stack_2(
            VerificationType::long2_type(),
            VerificationType::long_type(), CHECK_VERIFY(this));
          current_frame.push_stack_2(
            VerificationType::double_type(),
            VerificationType::double2_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_f2i :
          current_frame.pop_stack(
            VerificationType::float_type(), CHECK_VERIFY(this));
          current_frame.push_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_f2l :
          current_frame.pop_stack(
            VerificationType::float_type(), CHECK_VERIFY(this));
          current_frame.push_stack_2(
            VerificationType::long_type(),
            VerificationType::long2_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_f2d :
          current_frame.pop_stack(
            VerificationType::float_type(), CHECK_VERIFY(this));
          current_frame.push_stack_2(
            VerificationType::double_type(),
            VerificationType::double2_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_d2i :
          current_frame.pop_stack_2(
            VerificationType::double2_type(),
            VerificationType::double_type(), CHECK_VERIFY(this));
          current_frame.push_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_d2l :
          current_frame.pop_stack_2(
            VerificationType::double2_type(),
            VerificationType::double_type(), CHECK_VERIFY(this));
          current_frame.push_stack_2(
            VerificationType::long_type(),
            VerificationType::long2_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_d2f :
          current_frame.pop_stack_2(
            VerificationType::double2_type(),
            VerificationType::double_type(), CHECK_VERIFY(this));
          current_frame.push_stack(
            VerificationType::float_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_i2b :
        case Bytecodes::_i2c :
        case Bytecodes::_i2s :
          current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          current_frame.push_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_lcmp :
          current_frame.pop_stack_2(
            VerificationType::long2_type(),
            VerificationType::long_type(), CHECK_VERIFY(this));
          current_frame.pop_stack_2(
            VerificationType::long2_type(),
            VerificationType::long_type(), CHECK_VERIFY(this));
          current_frame.push_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_fcmpl :
        case Bytecodes::_fcmpg :
          current_frame.pop_stack(
            VerificationType::float_type(), CHECK_VERIFY(this));
          current_frame.pop_stack(
            VerificationType::float_type(), CHECK_VERIFY(this));
          current_frame.push_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_dcmpl :
        case Bytecodes::_dcmpg :
          current_frame.pop_stack_2(
            VerificationType::double2_type(),
            VerificationType::double_type(), CHECK_VERIFY(this));
          current_frame.pop_stack_2(
            VerificationType::double2_type(),
            VerificationType::double_type(), CHECK_VERIFY(this));
          current_frame.push_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_if_icmpeq:
        case Bytecodes::_if_icmpne:
        case Bytecodes::_if_icmplt:
        case Bytecodes::_if_icmpge:
        case Bytecodes::_if_icmpgt:
        case Bytecodes::_if_icmple:
          current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          // fall through
        case Bytecodes::_ifeq:
        case Bytecodes::_ifne:
        case Bytecodes::_iflt:
        case Bytecodes::_ifge:
        case Bytecodes::_ifgt:
        case Bytecodes::_ifle:
          current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          target = bcs.dest();
          stackmap_table.check_jump_target(
            &current_frame, target, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_if_acmpeq :
        case Bytecodes::_if_acmpne :
          current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          // fall through
        case Bytecodes::_ifnull :
        case Bytecodes::_ifnonnull :
          current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          target = bcs.dest();
          stackmap_table.check_jump_target
            (&current_frame, target, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_goto :
          target = bcs.dest();
          stackmap_table.check_jump_target(
            &current_frame, target, CHECK_VERIFY(this));
          no_control_flow = true; break;
        case Bytecodes::_goto_w :
          target = bcs.dest_w();
          stackmap_table.check_jump_target(
            &current_frame, target, CHECK_VERIFY(this));
          no_control_flow = true; break;
        case Bytecodes::_tableswitch :
        case Bytecodes::_lookupswitch :
          verify_switch(
            &bcs, code_length, code_data, &current_frame,
            &stackmap_table, CHECK_VERIFY(this));
          no_control_flow = true; break;
        case Bytecodes::_ireturn :
          type = current_frame.pop_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          verify_return_value(return_type, type, bci,
                              &current_frame, CHECK_VERIFY(this));
          no_control_flow = true; break;
        case Bytecodes::_lreturn :
          type2 = current_frame.pop_stack(
            VerificationType::long2_type(), CHECK_VERIFY(this));
          type = current_frame.pop_stack(
            VerificationType::long_type(), CHECK_VERIFY(this));
          verify_return_value(return_type, type, bci,
                              &current_frame, CHECK_VERIFY(this));
          no_control_flow = true; break;
        case Bytecodes::_freturn :
          type = current_frame.pop_stack(
            VerificationType::float_type(), CHECK_VERIFY(this));
          verify_return_value(return_type, type, bci,
                              &current_frame, CHECK_VERIFY(this));
          no_control_flow = true; break;
        case Bytecodes::_dreturn :
          type2 = current_frame.pop_stack(
            VerificationType::double2_type(),  CHECK_VERIFY(this));
          type = current_frame.pop_stack(
            VerificationType::double_type(), CHECK_VERIFY(this));
          verify_return_value(return_type, type, bci,
                              &current_frame, CHECK_VERIFY(this));
          no_control_flow = true; break;
        case Bytecodes::_areturn :
          type = current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          verify_return_value(return_type, type, bci,
                              &current_frame, CHECK_VERIFY(this));
          no_control_flow = true; break;
        case Bytecodes::_return :
          if (return_type != VerificationType::bogus_type()) {
            verify_error(ErrorContext::bad_code(bci),
                         "Method expects a return value");
            return;
          }
          // Make sure "this" has been initialized if current method is an
          // <init>
          if (_method->name() == vmSymbols::object_initializer_name() &&
              current_frame.flag_this_uninit()) {
            verify_error(ErrorContext::bad_code(bci),
                         "Constructor must call super() or this() "
                         "before return");
            return;
          }
          no_control_flow = true; break;
        case Bytecodes::_getstatic :
        case Bytecodes::_putstatic :
        case Bytecodes::_getfield :
        case Bytecodes::_putfield :
          verify_field_instructions(
            &bcs, &current_frame, cp, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_invokevirtual :
        case Bytecodes::_invokespecial :
        case Bytecodes::_invokestatic :
          verify_invoke_instructions(
            &bcs, code_length, &current_frame, (bci >= ex_min && bci < ex_max),
            &this_uninit, return_type, cp, &stackmap_table, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_invokeinterface :
        case Bytecodes::_invokedynamic :
          verify_invoke_instructions(
            &bcs, code_length, &current_frame, (bci >= ex_min && bci < ex_max),
            &this_uninit, return_type, cp, &stackmap_table, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_new :
        {
          index = bcs.get_index_u2();
          verify_cp_class_type(bci, index, cp, CHECK_VERIFY(this));
          VerificationType new_class_type =
            cp_index_to_type(index, cp, CHECK_VERIFY(this));
          if (!new_class_type.is_object()) {
            verify_error(ErrorContext::bad_type(bci,
                TypeOrigin::cp(index, new_class_type)),
                "Illegal new instruction");
            return;
          }
          type = VerificationType::uninitialized_type(bci);
          current_frame.push_stack(type, CHECK_VERIFY(this));
          no_control_flow = false; break;
        }
        case Bytecodes::_newarray :
          type = get_newarray_type(bcs.get_index(), bci, CHECK_VERIFY(this));
          current_frame.pop_stack(
            VerificationType::integer_type(),  CHECK_VERIFY(this));
          current_frame.push_stack(type, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_anewarray :
          verify_anewarray(
            bci, bcs.get_index_u2(), cp, &current_frame, CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_arraylength :
          type = current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          if (!(type.is_null() || type.is_array())) {
            verify_error(ErrorContext::bad_type(
                bci, current_frame.stack_top_ctx()),
                bad_type_msg, "arraylength");
          }
          current_frame.push_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_checkcast :
        {
          index = bcs.get_index_u2();
          verify_cp_class_type(bci, index, cp, CHECK_VERIFY(this));
          current_frame.pop_stack(object_type(), CHECK_VERIFY(this));
          VerificationType klass_type = cp_index_to_type(
            index, cp, CHECK_VERIFY(this));
          current_frame.push_stack(klass_type, CHECK_VERIFY(this));
          no_control_flow = false; break;
        }
        case Bytecodes::_instanceof : {
          index = bcs.get_index_u2();
          verify_cp_class_type(bci, index, cp, CHECK_VERIFY(this));
          current_frame.pop_stack(object_type(), CHECK_VERIFY(this));
          current_frame.push_stack(
            VerificationType::integer_type(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        }
        case Bytecodes::_monitorenter :
        case Bytecodes::_monitorexit :
          current_frame.pop_stack(
            VerificationType::reference_check(), CHECK_VERIFY(this));
          no_control_flow = false; break;
        case Bytecodes::_multianewarray :
        {
          index = bcs.get_index_u2();
          u2 dim = *(bcs.bcp()+3);
          verify_cp_class_type(bci, index, cp, CHECK_VERIFY(this));
          VerificationType new_array_type =
            cp_index_to_type(index, cp, CHECK_VERIFY(this));
          if (!new_array_type.is_array()) {
            verify_error(ErrorContext::bad_type(bci,
                TypeOrigin::cp(index, new_array_type)),
                "Illegal constant pool index in multianewarray instruction");
            return;
          }
          if (dim < 1 || new_array_type.dimensions() < dim) {
            verify_error(ErrorContext::bad_code(bci),
                "Illegal dimension in multianewarray instruction: %d", dim);
            return;
          }
          for (int i = 0; i < dim; i++) {
            current_frame.pop_stack(
              VerificationType::integer_type(), CHECK_VERIFY(this));
          }
          current_frame.push_stack(new_array_type, CHECK_VERIFY(this));
          no_control_flow = false; break;
        }
        case Bytecodes::_athrow :
          type = VerificationType::reference_type(
            vmSymbols::java_lang_Throwable());
          current_frame.pop_stack(type, CHECK_VERIFY(this));
          no_control_flow = true; break;
        default:
          // We only need to check the valid bytecodes in class file.
          // And jsr and ret are not in the new class file format in JDK1.5.
          verify_error(ErrorContext::bad_code(bci),
              "Bad instruction: %02x", opcode);
          no_control_flow = false;
          return;
      }  // end switch
    }  // end Merge with the next instruction

    // Look for possible jump target in exception handlers and see if it matches
    // current_frame.  Don't do this check if it has already been done (for
    // ([a,d,f,i,l]store* opcodes).  This check cannot be done earlier because
    // opcodes, such as invokespecial, may set the this_uninit flag.
    assert(!(verified_exc_handlers && this_uninit),
      "Exception handler targets got verified before this_uninit got set");
    if (!verified_exc_handlers && bci >= ex_min && bci < ex_max) {
      verify_exception_handler_targets(
        bci, this_uninit, &current_frame, &stackmap_table, CHECK_VERIFY(this));
    }
  } // end while

  // Make sure that control flow does not fall through end of the method
  if (!no_control_flow) {
    verify_error(ErrorContext::bad_code(code_length),
        "Control flow falls through code end");
    return;
  }
}