C++ (Cpp) InstanceKlass::find_field Examples

Example #1

File: diagnosticCommand.cpp Project: campolake/openjdk9

void FinalizerInfoDCmd::execute(DCmdSource source, TRAPS) {
  ResourceMark rm;


  Klass* k = SystemDictionary::resolve_or_null(
    vmSymbols::finalizer_histogram_klass(), THREAD);
  assert(k != NULL, "FinalizerHistogram class is not accessible");

  instanceKlassHandle klass(THREAD, k);
  JavaValue result(T_ARRAY);

  // We are calling lang.ref.FinalizerHistogram.getFinalizerHistogram() method
  // and expect it to return array of FinalizerHistogramEntry as Object[]

  JavaCalls::call_static(&result, klass,
                         vmSymbols::get_finalizer_histogram_name(),
                         vmSymbols::void_finalizer_histogram_entry_array_signature(), CHECK);

  objArrayOop result_oop = (objArrayOop) result.get_jobject();
  if (result_oop->length() == 0) {
    output()->print_cr("No instances waiting for finalization found");
    return;
  }

  oop foop = result_oop->obj_at(0);
  InstanceKlass* ik = InstanceKlass::cast(foop->klass());

  fieldDescriptor count_fd, name_fd;

  Klass* count_res = ik->find_field(
    vmSymbols::finalizer_histogram_entry_count_field(), vmSymbols::int_signature(), &count_fd);

  Klass* name_res = ik->find_field(
    vmSymbols::finalizer_histogram_entry_name_field(), vmSymbols::string_signature(), &name_fd);

  assert(count_res != NULL && name_res != NULL, "Unexpected layout of FinalizerHistogramEntry");

  output()->print_cr("Unreachable instances waiting for finalization");
  output()->print_cr("#instances  class name");
  output()->print_cr("-----------------------");

  for (int i = 0; i < result_oop->length(); ++i) {
    oop element_oop = result_oop->obj_at(i);
    oop str_oop = element_oop->obj_field(name_fd.offset());
    char *name = java_lang_String::as_utf8_string(str_oop);
    int count = element_oop->int_field(count_fd.offset());
    output()->print_cr("%10d  %s", count, name);
  }
}

Example #2

File: graalJavaAccess.cpp Project: pombreda/graal

void compute_offset(int &dest_offset, Klass* klass, const char* name, const char* signature, bool static_field) {
  Symbol* name_symbol = SymbolTable::probe(name, (int)strlen(name));
  Symbol* signature_symbol = SymbolTable::probe(signature, (int)strlen(signature));
  if (name_symbol == NULL || signature_symbol == NULL) {
    guarantee(false, err_msg("symbol with name %s and signature %s was not found in symbol table (klass=%s)", name, signature, klass->name()->as_C_string()));
  }

  InstanceKlass* ik = InstanceKlass::cast(klass);
  fieldDescriptor fd;
  if (!ik->find_field(name_symbol, signature_symbol, &fd)) {
    ResourceMark rm;
    fatal(err_msg("Invalid layout of %s at %s", name_symbol->as_C_string(), ik->external_name()));
  }
  guarantee(fd.is_static() == static_field, "static/instance mismatch");
  dest_offset = fd.offset();
}