C++ methodHandle::signature方法代码示例

// Check if there are any JVM TI prefixes which have been applied to the native method name.
// If any are found, remove them before attemping the look up of the
// native implementation again.
// See SetNativeMethodPrefix in the JVM TI Spec for more details.
address NativeLookup::lookup_entry_prefixed(methodHandle method, bool& in_base_library, TRAPS) {
  ResourceMark rm(THREAD);

  int prefix_count;
  char** prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
  char* in_name = method->name()->as_C_string();
  char* wrapper_name = in_name;
  // last applied prefix will be first -- go backwards
  for (int i = prefix_count-1; i >= 0; i--) {
    char* prefix = prefixes[i];
    size_t prefix_len = strlen(prefix);
    if (strncmp(prefix, wrapper_name, prefix_len) == 0) {
      // has this prefix remove it
      wrapper_name += prefix_len;
    }
  }
  if (wrapper_name != in_name) {
    // we have a name for a wrapping method
    int wrapper_name_len = (int)strlen(wrapper_name);
    TempNewSymbol wrapper_symbol = SymbolTable::probe(wrapper_name, wrapper_name_len);
    if (wrapper_symbol != NULL) {
      KlassHandle kh(method->method_holder());
      methodOop wrapper_method = Klass::cast(kh())->lookup_method(wrapper_symbol,
                                                                  method->signature());
      if (wrapper_method != NULL && !wrapper_method->is_native()) {
        // we found a wrapper method, use its native entry
        method->set_is_prefixed_native();
        return lookup_entry(wrapper_method, in_base_library, THREAD);
      }
    }
  }
  return NULL;
}

  NativeSignatureIterator(methodHandle method) : SignatureIterator(method->signature()) {
    _method = method;
    _offset = 0;
    _jni_offset = 0;

    const int JNIEnv_words = 1;
    const int mirror_words = 1;
    _prepended = !is_static() ? JNIEnv_words : JNIEnv_words + mirror_words;
  }

VerificationType StackMapFrame::set_locals_from_arg(
    const methodHandle m, VerificationType thisKlass, TRAPS) {
  SignatureStream ss(m->signature());
  int init_local_num = 0;
  if (!m->is_static()) {
    init_local_num++;
    // add one extra argument for instance method
    if (m->name() == vmSymbols::object_initializer_name() &&
       thisKlass.name() != vmSymbols::java_lang_Object()) {
      _locals[0] = VerificationType::uninitialized_this_type();
      _flags |= FLAG_THIS_UNINIT;
    } else {
      _locals[0] = thisKlass;
    }
  }

  // local num may be greater than size of parameters because long/double occupies two slots
  while(!ss.at_return_type()) {
    init_local_num += _verifier->change_sig_to_verificationType(
      &ss, &_locals[init_local_num],
      CHECK_VERIFY_(verifier(), VerificationType::bogus_type()));
    ss.next();
  }
  _locals_size = init_local_num;

  switch (ss.type()) {
    case T_OBJECT:
    case T_ARRAY:
    {
      Symbol* sig = ss.as_symbol(CHECK_(VerificationType::bogus_type()));
      // Create another symbol to save as signature stream unreferences
      // this symbol.
      Symbol* sig_copy =
        verifier()->create_temporary_symbol(sig, 0, sig->utf8_length(),
                                 CHECK_(VerificationType::bogus_type()));
      assert(sig_copy == sig, "symbols don't match");
      return VerificationType::reference_type(sig_copy);
    }
    case T_INT:     return VerificationType::integer_type();
    case T_BYTE:    return VerificationType::byte_type();
    case T_CHAR:    return VerificationType::char_type();
    case T_SHORT:   return VerificationType::short_type();
    case T_BOOLEAN: return VerificationType::boolean_type();
    case T_FLOAT:   return VerificationType::float_type();
    case T_DOUBLE:  return VerificationType::double_type();
    case T_LONG:    return VerificationType::long_type();
    case T_VOID:    return VerificationType::bogus_type();
    default:
      ShouldNotReachHere();
  }
  return VerificationType::bogus_type();
}

void JavaCalls::call_default_constructor(JavaThread* thread, methodHandle method, Handle receiver, TRAPS) {
  assert(method->name() == vmSymbols::object_initializer_name(),    "Should only be called for default constructor");
  assert(method->signature() == vmSymbols::void_method_signature(), "Should only be called for default constructor");

  InstanceKlass* ik = method->method_holder();
  if (ik->is_initialized() && ik->has_vanilla_constructor()) {
    // safe to skip constructor call
  } else {
    static JavaValue result(T_VOID);
    JavaCallArguments args(receiver);
    call(&result, method, &args, CHECK);
  }
}

// Check all the formats of native implementation name to see if there is one
// for the specified method.
address NativeLookup::lookup_critical_entry(methodHandle method) {
  if (!CriticalJNINatives) return NULL;

  if (method->is_synchronized() ||
      !method->is_static()) {
    // Only static non-synchronized methods are allowed
    return NULL;
  }

  ResourceMark rm;
  address entry = NULL;

  Symbol* signature = method->signature();
  for (int end = 0; end < signature->utf8_length(); end++) {
    if (signature->byte_at(end) == 'L') {
      // Don't allow object types
      return NULL;
    }
  }

  // Compute critical name
  char* critical_name = critical_jni_name(method);

  // Compute argument size
  int args_size = 1                             // JNIEnv
                + (method->is_static() ? 1 : 0) // class for static methods
                + method->size_of_parameters(); // actual parameters


  // 1) Try JNI short style
  entry = lookup_critical_style(method, critical_name, "",        args_size, true);
  if (entry != NULL) return entry;

  // Compute long name
  char* long_name = long_jni_name(method);

  // 2) Try JNI long style
  entry = lookup_critical_style(method, critical_name, long_name, args_size, true);
  if (entry != NULL) return entry;

  // 3) Try JNI short style without os prefix/suffix
  entry = lookup_critical_style(method, critical_name, "",        args_size, false);
  if (entry != NULL) return entry;

  // 4) Try JNI long style without os prefix/suffix
  entry = lookup_critical_style(method, critical_name, long_name, args_size, false);

  return entry; // NULL indicates not found
}

 Fingerprinter(methodHandle method) : SignatureIterator(method->signature()) {
   mh = method;
   _fingerprint = 0;
 }

 Fingerprinter(Thread *thread, methodHandle method) : SignatureIterator(thread, method->signature()) {
   mh = method;
   _fingerprint = 0;
 }