hotspot/src/share/vm/ci/ciInstanceKlass.cpp

/*
 * Copyright 1999-2007 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 */

#include "incls/_precompiled.incl"
#include "incls/_ciInstanceKlass.cpp.incl"

// ciInstanceKlass
//
// This class represents a klassOop in the HotSpot virtual machine
// whose Klass part in an instanceKlass.

// ------------------------------------------------------------------
// ciInstanceKlass::ciInstanceKlass
//
// Loaded instance klass.
ciInstanceKlass::ciInstanceKlass(KlassHandle h_k) : ciKlass(h_k) {
  assert(get_Klass()->oop_is_instance(), "wrong type");
  instanceKlass* ik = get_instanceKlass();

  AccessFlags access_flags = ik->access_flags();
  _flags = ciFlags(access_flags);
  _has_finalizer = access_flags.has_finalizer();
  _has_subklass = ik->subklass() != NULL;
  _is_initialized = ik->is_initialized();
  // Next line must follow and use the result of the previous line:
  _is_linked = _is_initialized || ik->is_linked();
  _nonstatic_field_size = ik->nonstatic_field_size();
  _nonstatic_fields = NULL; // initialized lazily by compute_nonstatic_fields:

  _nof_implementors = ik->nof_implementors();
  for (int i = 0; i < implementors_limit; i++) {
    _implementors[i] = NULL;  // we will fill these lazily
  }

  Thread *thread = Thread::current();
  if (ciObjectFactory::is_initialized()) {
    _loader = JNIHandles::make_local(thread, ik->class_loader());
    _protection_domain = JNIHandles::make_local(thread,
                                                ik->protection_domain());
    _is_shared = false;
  } else {
    Handle h_loader(thread, ik->class_loader());
    Handle h_protection_domain(thread, ik->protection_domain());
    _loader = JNIHandles::make_global(h_loader);
    _protection_domain = JNIHandles::make_global(h_protection_domain);
    _is_shared = true;
  }

  // Lazy fields get filled in only upon request.
  _super  = NULL;
  _java_mirror = NULL;

  if (is_shared()) {
    if (h_k() != SystemDictionary::object_klass()) {
      super();
    }
    java_mirror();
    //compute_nonstatic_fields();  // done outside of constructor
  }

  _field_cache = NULL;
}

// Version for unloaded classes:
ciInstanceKlass::ciInstanceKlass(ciSymbol* name,
                                 jobject loader, jobject protection_domain)
  : ciKlass(name, ciInstanceKlassKlass::make())
{
  assert(name->byte_at(0) != '[', "not an instance klass");
  _is_initialized = false;
  _is_linked = false;
  _nonstatic_field_size = -1;
  _nonstatic_fields = NULL;
  _nof_implementors = -1;
  _loader = loader;
  _protection_domain = protection_domain;
  _is_shared = false;
  _super = NULL;
  _java_mirror = NULL;
  _field_cache = NULL;
}



// ------------------------------------------------------------------
// ciInstanceKlass::compute_shared_is_initialized
bool ciInstanceKlass::compute_shared_is_initialized() {
  GUARDED_VM_ENTRY(
    instanceKlass* ik = get_instanceKlass();
    _is_initialized = ik->is_initialized();
    return _is_initialized;
  )
}

// ------------------------------------------------------------------
// ciInstanceKlass::compute_shared_is_linked
bool ciInstanceKlass::compute_shared_is_linked() {
  GUARDED_VM_ENTRY(
    instanceKlass* ik = get_instanceKlass();
    _is_linked = ik->is_linked();
    return _is_linked;
  )
}

// ------------------------------------------------------------------
// ciInstanceKlass::compute_shared_has_subklass
bool ciInstanceKlass::compute_shared_has_subklass() {
  GUARDED_VM_ENTRY(
    instanceKlass* ik = get_instanceKlass();
    _has_subklass = ik->subklass() != NULL;
    return _has_subklass;
  )
}

// ------------------------------------------------------------------
// ciInstanceKlass::compute_shared_nof_implementors
int ciInstanceKlass::compute_shared_nof_implementors() {
  // We requery this property, since it is a very old ciObject.
  GUARDED_VM_ENTRY(
    instanceKlass* ik = get_instanceKlass();
    _nof_implementors = ik->nof_implementors();
    return _nof_implementors;
  )
}

// ------------------------------------------------------------------
// ciInstanceKlass::loader
oop ciInstanceKlass::loader() {
  ASSERT_IN_VM;
  return JNIHandles::resolve(_loader);
}

// ------------------------------------------------------------------
// ciInstanceKlass::loader_handle
jobject ciInstanceKlass::loader_handle() {
  return _loader;
}

// ------------------------------------------------------------------
// ciInstanceKlass::protection_domain
oop ciInstanceKlass::protection_domain() {
  ASSERT_IN_VM;
  return JNIHandles::resolve(_protection_domain);
}

// ------------------------------------------------------------------
// ciInstanceKlass::protection_domain_handle
jobject ciInstanceKlass::protection_domain_handle() {
  return _protection_domain;
}

// ------------------------------------------------------------------
// ciInstanceKlass::field_cache
//
// Get the field cache associated with this klass.
ciConstantPoolCache* ciInstanceKlass::field_cache() {
  if (is_shared()) {
    return NULL;
  }
  if (_field_cache == NULL) {
    assert(!is_java_lang_Object(), "Object has no fields");
    Arena* arena = CURRENT_ENV->arena();
    _field_cache = new (arena) ciConstantPoolCache(arena, 5);
  }
  return _field_cache;
}

// ------------------------------------------------------------------
// ciInstanceKlass::get_canonical_holder
//
ciInstanceKlass* ciInstanceKlass::get_canonical_holder(int offset) {
  #ifdef ASSERT
  if (!(offset >= 0 && offset < layout_helper())) {
    tty->print("*** get_canonical_holder(%d) on ", offset);
    this->print();
    tty->print_cr(" ***");
  };
  assert(offset >= 0 && offset < layout_helper(), "offset must be tame");
  #endif

  if (offset < (instanceOopDesc::header_size() * wordSize)) {
    // All header offsets belong properly to java/lang/Object.
    return CURRENT_ENV->Object_klass();
  }

  ciInstanceKlass* self = this;
  for (;;) {
    assert(self->is_loaded(), "must be loaded to have size");
    ciInstanceKlass* super = self->super();
    if (super == NULL || !super->contains_field_offset(offset)) {
      return self;
    } else {
      self = super;  // return super->get_canonical_holder(offset)
    }
  }
}

// ------------------------------------------------------------------
// ciInstanceKlass::is_java_lang_Object
//
// Is this klass java.lang.Object?
bool ciInstanceKlass::is_java_lang_Object() {
  return equals(CURRENT_ENV->Object_klass());
}

// ------------------------------------------------------------------
// ciInstanceKlass::uses_default_loader
bool ciInstanceKlass::uses_default_loader() {
  VM_ENTRY_MARK;
  return loader() == NULL;
}

// ------------------------------------------------------------------
// ciInstanceKlass::print_impl
//
// Implementation of the print method.
void ciInstanceKlass::print_impl(outputStream* st) {
  ciKlass::print_impl(st);
  GUARDED_VM_ENTRY(st->print(" loader=0x%x", (address)loader());)
  if (is_loaded()) {
    st->print(" loaded=true initialized=%s finalized=%s subklass=%s size=%d flags=",
              bool_to_str(is_initialized()),
              bool_to_str(has_finalizer()),
              bool_to_str(has_subklass()),
              layout_helper());

    _flags.print_klass_flags();

    if (_super) {
      st->print(" super=");
      _super->print_name();
    }
    if (_java_mirror) {
      st->print(" mirror=PRESENT");
    }
  } else {
    st->print(" loaded=false");
  }
}

// ------------------------------------------------------------------
// ciInstanceKlass::super
//
// Get the superklass of this klass.
ciInstanceKlass* ciInstanceKlass::super() {
  assert(is_loaded(), "must be loaded");
  if (_super == NULL && !is_java_lang_Object()) {
    GUARDED_VM_ENTRY(
      klassOop super_klass = get_instanceKlass()->super();
      _super = CURRENT_ENV->get_object(super_klass)->as_instance_klass();
    )
  }
  return _super;
}

// ------------------------------------------------------------------
// ciInstanceKlass::java_mirror
//
// Get the instance of java.lang.Class corresponding to this klass.
ciInstance* ciInstanceKlass::java_mirror() {
  assert(is_loaded(), "must be loaded");
  if (_java_mirror == NULL) {
    _java_mirror = ciKlass::java_mirror();
  }
  return _java_mirror;
}

// ------------------------------------------------------------------
// ciInstanceKlass::unique_concrete_subklass
ciInstanceKlass* ciInstanceKlass::unique_concrete_subklass() {
  if (!is_loaded())     return NULL; // No change if class is not loaded
  if (!is_abstract())   return NULL; // Only applies to abstract classes.
  if (!has_subklass())  return NULL; // Must have at least one subklass.
  VM_ENTRY_MARK;
  instanceKlass* ik = get_instanceKlass();
  Klass* up = ik->up_cast_abstract();
  assert(up->oop_is_instance(), "must be instanceKlass");
  if (ik == up) {
    return NULL;
  }
  return CURRENT_THREAD_ENV->get_object(up->as_klassOop())->as_instance_klass();
}

// ------------------------------------------------------------------
// ciInstanceKlass::has_finalizable_subclass
bool ciInstanceKlass::has_finalizable_subclass() {
  if (!is_loaded())     return true;
  VM_ENTRY_MARK;
  return Dependencies::find_finalizable_subclass(get_instanceKlass()) != NULL;
}

// ------------------------------------------------------------------
// ciInstanceKlass::get_field_by_offset
ciField* ciInstanceKlass::get_field_by_offset(int field_offset, bool is_static) {
  if (!is_static) {
    for (int i = 0, len = nof_nonstatic_fields(); i < len; i++) {
      ciField* field = _nonstatic_fields->at(i);
      int  field_off = field->offset_in_bytes();
      if (field_off == field_offset)
        return field;
      if (field_off > field_offset)
        break;
      // could do binary search or check bins, but probably not worth it
    }
    return NULL;
  }
  VM_ENTRY_MARK;
  instanceKlass* k = get_instanceKlass();
  fieldDescriptor fd;
  if (!k->find_field_from_offset(field_offset, is_static, &fd)) {
    return NULL;
  }
  ciField* field = new (CURRENT_THREAD_ENV->arena()) ciField(&fd);
  return field;
}

static int sort_field_by_offset(ciField** a, ciField** b) {
  return (*a)->offset_in_bytes() - (*b)->offset_in_bytes();
  // (no worries about 32-bit overflow...)
}

// ------------------------------------------------------------------
// ciInstanceKlass::compute_nonstatic_fields
int ciInstanceKlass::compute_nonstatic_fields() {
  assert(is_loaded(), "must be loaded");

  if (_nonstatic_fields != NULL)
    return _nonstatic_fields->length();

  // Size in bytes of my fields, including inherited fields.
  // About equal to size_helper() - sizeof(oopDesc).
  int fsize = nonstatic_field_size() * wordSize;
  if (fsize == 0) {     // easy shortcut
    Arena* arena = CURRENT_ENV->arena();
    _nonstatic_fields = new (arena) GrowableArray<ciField*>(arena, 0, 0, NULL);
    return 0;
  }
  assert(!is_java_lang_Object(), "bootstrap OK");

  ciInstanceKlass* super = this->super();
  int      super_fsize = 0;
  int      super_flen  = 0;
  GrowableArray<ciField*>* super_fields = NULL;
  if (super != NULL) {
    super_fsize  = super->nonstatic_field_size() * wordSize;
    super_flen   = super->nof_nonstatic_fields();
    super_fields = super->_nonstatic_fields;
    assert(super_flen == 0 || super_fields != NULL, "first get nof_fields");
  }

  // See if I am no larger than my super; if so, I can use his fields.
  if (fsize == super_fsize) {
    _nonstatic_fields = super_fields;
    return super_fields->length();
  }

  GrowableArray<ciField*>* fields = NULL;
  GUARDED_VM_ENTRY({
      fields = compute_nonstatic_fields_impl(super_fields);
    });

  if (fields == NULL) {
    // This can happen if this class (java.lang.Class) has invisible fields.
    _nonstatic_fields = super_fields;
    return super_fields->length();
  }

  int flen = fields->length();

  // Now sort them by offset, ascending.
  // (In principle, they could mix with superclass fields.)
  fields->sort(sort_field_by_offset);
#ifdef ASSERT
  int last_offset = sizeof(oopDesc);
  for (int i = 0; i < fields->length(); i++) {
    ciField* field = fields->at(i);
    int offset = field->offset_in_bytes();
    int size   = (field->_type == NULL) ? oopSize : field->size_in_bytes();
    assert(last_offset <= offset, "no field overlap");
    if (last_offset > (int)sizeof(oopDesc))
      assert((offset - last_offset) < BytesPerLong, "no big holes");
    // Note:  Two consecutive T_BYTE fields will be separated by wordSize-1
    // padding bytes if one of them is declared by a superclass.
    // This is a minor inefficiency classFileParser.cpp.
    last_offset = offset + size;
  }
  assert(last_offset <= (int)sizeof(oopDesc) + fsize, "no overflow");
#endif

  _nonstatic_fields = fields;
  return flen;
}

GrowableArray<ciField*>*
ciInstanceKlass::compute_nonstatic_fields_impl(GrowableArray<ciField*>*
                                               super_fields) {
  ASSERT_IN_VM;
  Arena* arena = CURRENT_ENV->arena();
  int flen = 0;
  GrowableArray<ciField*>* fields = NULL;
  instanceKlass* k = get_instanceKlass();
  typeArrayOop fields_array = k->fields();
  for (int pass = 0; pass <= 1; pass++) {
    for (int i = 0, alen = fields_array->length(); i < alen; i += instanceKlass::next_offset) {
      fieldDescriptor fd;
      fd.initialize(k->as_klassOop(), i);
      if (fd.is_static())  continue;
      if (pass == 0) {
        flen += 1;
      } else {
        ciField* field = new (arena) ciField(&fd);
        fields->append(field);
      }
    }

    // Between passes, allocate the array:
    if (pass == 0) {
      if (flen == 0) {
        return NULL;  // return nothing if none are locally declared
      }
      if (super_fields != NULL) {
        flen += super_fields->length();
      }
      fields = new (arena) GrowableArray<ciField*>(arena, flen, 0, NULL);
      if (super_fields != NULL) {
        fields->appendAll(super_fields);
      }
    }
  }
  assert(fields->length() == flen, "sanity");
  return fields;
}

// ------------------------------------------------------------------
// ciInstanceKlass::find_method
//
// Find a method in this klass.
ciMethod* ciInstanceKlass::find_method(ciSymbol* name, ciSymbol* signature) {
  VM_ENTRY_MARK;
  instanceKlass* k = get_instanceKlass();
  symbolOop name_sym = name->get_symbolOop();
  symbolOop sig_sym= signature->get_symbolOop();

  methodOop m = k->find_method(name_sym, sig_sym);
  if (m == NULL)  return NULL;

  return CURRENT_THREAD_ENV->get_object(m)->as_method();
}

// ------------------------------------------------------------------
// ciInstanceKlass::is_leaf_type
bool ciInstanceKlass::is_leaf_type() {
  assert(is_loaded(), "must be loaded");
  if (is_shared()) {
    return is_final();  // approximately correct
  } else {
    return !_has_subklass && (_nof_implementors == 0);
  }
}

// ------------------------------------------------------------------
// ciInstanceKlass::implementor
//
// Report an implementor of this interface.
// Returns NULL if exact information is not available.
// Note that there are various races here, since my copy
// of _nof_implementors might be out of date with respect
// to results returned by instanceKlass::implementor.
// This is OK, since any dependencies we decide to assert
// will be checked later under the Compile_lock.
ciInstanceKlass* ciInstanceKlass::implementor(int n) {
  if (n > implementors_limit) {
    return NULL;
  }
  ciInstanceKlass* impl = _implementors[n];
  if (impl == NULL) {
    if (_nof_implementors > implementors_limit) {
      return NULL;
    }
    // Go into the VM to fetch the implementor.
    {
      VM_ENTRY_MARK;
      klassOop k = get_instanceKlass()->implementor(n);
      if (k != NULL) {
        impl = CURRENT_THREAD_ENV->get_object(k)->as_instance_klass();
      }
    }
    // Memoize this result.
    if (!is_shared()) {
      _implementors[n] = (impl == NULL)? this: impl;
    }
  } else if (impl == this) {
    impl = NULL;  // memoized null result from a VM query
  }
  return impl;
}