/*

 * Copyright (c) 1997, 2012, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "classfile/systemDictionary.hpp"

#include "classfile/vmSymbols.hpp"

#include "gc_interface/collectedHeap.inline.hpp"

#include "memory/oopFactory.hpp"

#include "memory/resourceArea.hpp"

#include "oops/instanceKlass.hpp"

#include "oops/klass.inline.hpp"

#include "oops/klassOop.hpp"

#include "oops/oop.inline.hpp"

#include "oops/oop.inline2.hpp"

#include "runtime/atomic.hpp"

void Klass::set_name(Symbol* n) {

  _name = n;

  if (_name != NULL) _name->increment_refcount();

}

bool Klass::is_subclass_of(klassOop k) const {

  // Run up the super chain and check

  klassOop t = as_klassOop();

  if (t == k) return true;

  t = Klass::cast(t)->super();

  while (t != NULL) {

    if (t == k) return true;

    t = Klass::cast(t)->super();

  }

  return false;

}

bool Klass::search_secondary_supers(klassOop k) const {

  // Put some extra logic here out-of-line, before the search proper.

  // This cuts down the size of the inline method.

  // This is necessary, since I am never in my own secondary_super list.

  if (this->as_klassOop() == k)

    return true;

  // Scan the array-of-objects for a match

  int cnt = secondary_supers()->length();

  for (int i = 0; i < cnt; i++) {

    if (secondary_supers()->obj_at(i) == k) {

      ((Klass*)this)->set_secondary_super_cache(k);

      return true;

    }

  }

  return false;

}

// Return self, except for abstract classes with exactly 1

// implementor.  Then return the 1 concrete implementation.

Klass *Klass::up_cast_abstract() {

  Klass *r = this;

  while( r->is_abstract() ) {   // Receiver is abstract?

    Klass *s = r->subklass();   // Check for exactly 1 subklass

    if( !s || s->next_sibling() ) // Oops; wrong count; give up

      return this;              // Return 'this' as a no-progress flag

    r = s;                    // Loop till find concrete class

  }

  return r;                   // Return the 1 concrete class

}

// Find LCA in class hierarchy

Klass *Klass::LCA( Klass *k2 ) {

  Klass *k1 = this;

  while( 1 ) {

    if( k1->is_subtype_of(k2->as_klassOop()) ) return k2;

    if( k2->is_subtype_of(k1->as_klassOop()) ) return k1;

    k1 = k1->super()->klass_part();

    k2 = k2->super()->klass_part();

  }

}

void Klass::check_valid_for_instantiation(bool throwError, TRAPS) {

  ResourceMark rm(THREAD);

  THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()

            : vmSymbols::java_lang_InstantiationException(), external_name());

}

void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) {

  THROW(vmSymbols::java_lang_ArrayStoreException());

}

void Klass::initialize(TRAPS) {

  ShouldNotReachHere();

}

bool Klass::compute_is_subtype_of(klassOop k) {

  assert(k->is_klass(), "argument must be a class");

  return is_subclass_of(k);

}

methodOop Klass::uncached_lookup_method(Symbol* name, Symbol* signature) const {

#ifdef ASSERT

  tty->print_cr("Error: uncached_lookup_method called on a klass oop."

                " Likely error: reflection method does not correctly"

                " wrap return value in a mirror object.");

#endif

  ShouldNotReachHere();

  return NULL;

}

klassOop Klass::base_create_klass_oop(KlassHandle& klass, int size,

                                      const Klass_vtbl& vtbl, TRAPS) {

  size = align_object_size(size);

  // allocate and initialize vtable

  Klass*   kl = (Klass*) vtbl.allocate_permanent(klass, size, CHECK_NULL);

  klassOop k  = kl->as_klassOop();

  { // Preinitialize supertype information.

    // A later call to initialize_supers() may update these settings:

    kl->set_super(NULL);

    for (juint i = 0; i < Klass::primary_super_limit(); i++) {

      kl->_primary_supers[i] = NULL;

    }

    kl->set_secondary_supers(NULL);

    oop_store_without_check((oop*) &kl->_primary_supers[0], k);

    kl->set_super_check_offset(in_bytes(primary_supers_offset()));

  }

  kl->set_java_mirror(NULL);

  kl->set_modifier_flags(0);

  kl->set_layout_helper(Klass::_lh_neutral_value);

  kl->set_name(NULL);

  AccessFlags af;

  af.set_flags(0);

  kl->set_access_flags(af);

  kl->set_subklass(NULL);

  kl->set_next_sibling(NULL);

  kl->set_alloc_count(0);

  kl->set_alloc_size(0);

  TRACE_SET_KLASS_TRACE_ID(kl, 0);

  kl->set_prototype_header(markOopDesc::prototype());

  kl->set_biased_lock_revocation_count(0);

  kl->set_last_biased_lock_bulk_revocation_time(0);

  return k;

}

KlassHandle Klass::base_create_klass(KlassHandle& klass, int size,

                                     const Klass_vtbl& vtbl, TRAPS) {

  klassOop ek = base_create_klass_oop(klass, size, vtbl, THREAD);

  return KlassHandle(THREAD, ek);

}

void Klass_vtbl::post_new_init_klass(KlassHandle& klass,

                                     klassOop new_klass) const {

  assert(!new_klass->klass_part()->null_vtbl(), "Not a complete klass");

  CollectedHeap::post_allocation_install_obj_klass(klass, new_klass);

}

void* Klass_vtbl::operator new(size_t ignored, KlassHandle& klass,

                               int size, TRAPS) {

  // The vtable pointer is installed during the execution of

  // constructors in the call to permanent_obj_allocate().  Delay

  // the installation of the klass pointer into the new klass "k"

  // until after the vtable pointer has been installed (i.e., until

  // after the return of permanent_obj_allocate().

  klassOop k =

    (klassOop) CollectedHeap::permanent_obj_allocate_no_klass_install(klass,

      size, CHECK_NULL);

  return k->klass_part();

}

jint Klass::array_layout_helper(BasicType etype) {

  assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");

  // Note that T_ARRAY is not allowed here.

  int  hsize = arrayOopDesc::base_offset_in_bytes(etype);

  int  esize = type2aelembytes(etype);

  bool isobj = (etype == T_OBJECT);

  int  tag   =  isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;

  int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize));

  assert(lh < (int)_lh_neutral_value, "must look like an array layout");

  assert(layout_helper_is_javaArray(lh), "correct kind");

  assert(layout_helper_is_objArray(lh) == isobj, "correct kind");

  assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");

  assert(layout_helper_header_size(lh) == hsize, "correct decode");

  assert(layout_helper_element_type(lh) == etype, "correct decode");

  assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");

  return lh;

}

bool Klass::can_be_primary_super_slow() const {

  if (super() == NULL)

    return true;

  else if (super()->klass_part()->super_depth() >= primary_super_limit()-1)

    return false;

  else

    return true;

}

void Klass::initialize_supers(klassOop k, TRAPS) {

  if (FastSuperclassLimit == 0) {

    // None of the other machinery matters.

    set_super(k);

    return;

  }

  if (k == NULL) {

    set_super(NULL);

    oop_store_without_check((oop*) &_primary_supers[0], (oop) this->as_klassOop());

    assert(super_depth() == 0, "Object must already be initialized properly");

  } else if (k != super() || k == SystemDictionary::Object_klass()) {

    assert(super() == NULL || super() == SystemDictionary::Object_klass(),

           "initialize this only once to a non-trivial value");

    set_super(k);

    Klass* sup = k->klass_part();

    int sup_depth = sup->super_depth();

    juint my_depth  = MIN2(sup_depth + 1, (int)primary_super_limit());

    if (!can_be_primary_super_slow())

      my_depth = primary_super_limit();

    for (juint i = 0; i < my_depth; i++) {

      oop_store_without_check((oop*) &_primary_supers[i], (oop) sup->_primary_supers[i]);

    }

    klassOop *super_check_cell;

    if (my_depth < primary_super_limit()) {

      oop_store_without_check((oop*) &_primary_supers[my_depth], (oop) this->as_klassOop());

      super_check_cell = &_primary_supers[my_depth];

    } else {

      // Overflow of the primary_supers array forces me to be secondary.

      super_check_cell = &_secondary_super_cache;

    }

    set_super_check_offset((address)super_check_cell - (address) this->as_klassOop());

#ifdef ASSERT

    {

      juint j = super_depth();

      assert(j == my_depth, "computed accessor gets right answer");

      klassOop t = as_klassOop();

      while (!Klass::cast(t)->can_be_primary_super()) {

        t = Klass::cast(t)->super();

        j = Klass::cast(t)->super_depth();

      }

      for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {

        assert(primary_super_of_depth(j1) == NULL, "super list padding");

      }

      while (t != NULL) {

        assert(primary_super_of_depth(j) == t, "super list initialization");

        t = Klass::cast(t)->super();

        --j;

      }

      assert(j == (juint)-1, "correct depth count");

    }

#endif

  }

  if (secondary_supers() == NULL) {

    KlassHandle this_kh (THREAD, this);

    // Now compute the list of secondary supertypes.

    // Secondaries can occasionally be on the super chain,

    // if the inline "_primary_supers" array overflows.

    int extras = 0;

    klassOop p;

    for (p = super(); !(p == NULL || p->klass_part()->can_be_primary_super()); p = p->klass_part()->super()) {

      ++extras;

    }

    // Compute the "real" non-extra secondaries.

    objArrayOop secondary_oops = compute_secondary_supers(extras, CHECK);

    objArrayHandle secondaries (THREAD, secondary_oops);

    // Store the extra secondaries in the first array positions:

    int fillp = extras;

    for (p = this_kh->super(); !(p == NULL || p->klass_part()->can_be_primary_super()); p = p->klass_part()->super()) {

      int i;                    // Scan for overflow primaries being duplicates of 2nd'arys

      // This happens frequently for very deeply nested arrays: the

      // primary superclass chain overflows into the secondary.  The

      // secondary list contains the element_klass's secondaries with

      // an extra array dimension added.  If the element_klass's

      // secondary list already contains some primary overflows, they

      // (with the extra level of array-ness) will collide with the

      // normal primary superclass overflows.

      for( i = extras; i < secondaries->length(); i++ )

        if( secondaries->obj_at(i) == p )

          break;

      if( i < secondaries->length() )

        continue;               // It's a dup, don't put it in

      secondaries->obj_at_put(--fillp, p);

    }

    // See if we had some dup's, so the array has holes in it.

    if( fillp > 0 ) {

      // Pack the array.  Drop the old secondaries array on the floor

      // and let GC reclaim it.

      objArrayOop s2 = oopFactory::new_system_objArray(secondaries->length() - fillp, CHECK);

      for( int i = 0; i < s2->length(); i++ )

        s2->obj_at_put( i, secondaries->obj_at(i+fillp) );

      secondaries = objArrayHandle(THREAD, s2);

    }

  #ifdef ASSERT

    if (secondaries() != Universe::the_array_interfaces_array()) {

      // We must not copy any NULL placeholders left over from bootstrap.

      for (int j = 0; j < secondaries->length(); j++) {

        assert(secondaries->obj_at(j) != NULL, "correct bootstrapping order");

      }

    }

  #endif

    this_kh->set_secondary_supers(secondaries());

  }

}

objArrayOop Klass::compute_secondary_supers(int num_extra_slots, TRAPS) {

  assert(num_extra_slots == 0, "override for complex klasses");

  return Universe::the_empty_system_obj_array();

}

Klass* Klass::subklass() const {

  return _subklass == NULL ? NULL : Klass::cast(_subklass);

}

instanceKlass* Klass::superklass() const {

  assert(super() == NULL || super()->klass_part()->oop_is_instance(), "must be instance klass");

  return _super == NULL ? NULL : instanceKlass::cast(_super);

}

Klass* Klass::next_sibling() const {

  return _next_sibling == NULL ? NULL : Klass::cast(_next_sibling);

}

void Klass::set_subklass(klassOop s) {

  assert(s != as_klassOop(), "sanity check");

  oop_store_without_check((oop*)&_subklass, s);

}

void Klass::set_next_sibling(klassOop s) {

  assert(s != as_klassOop(), "sanity check");

  oop_store_without_check((oop*)&_next_sibling, s);

}

void Klass::append_to_sibling_list() {

  debug_only(if (!SharedSkipVerify) as_klassOop()->verify();)

  // add ourselves to superklass' subklass list

  instanceKlass* super = superklass();

  if (super == NULL) return;        // special case: class Object

  assert(SharedSkipVerify ||

         (!super->is_interface()    // interfaces cannot be supers

          && (super->superklass() == NULL || !is_interface())),

         "an interface can only be a subklass of Object");

  klassOop prev_first_subklass = super->subklass_oop();

  if (prev_first_subklass != NULL) {

    // set our sibling to be the superklass' previous first subklass

    set_next_sibling(prev_first_subklass);

  }

  // make ourselves the superklass' first subklass

  super->set_subklass(as_klassOop());

  debug_only(if (!SharedSkipVerify) as_klassOop()->verify();)

}

void Klass::remove_from_sibling_list() {

  // remove receiver from sibling list

  instanceKlass* super = superklass();

  assert(super != NULL || as_klassOop() == SystemDictionary::Object_klass(), "should have super");

  if (super == NULL) return;        // special case: class Object

  if (super->subklass() == this) {

    // first subklass

    super->set_subklass(_next_sibling);

  } else {

    Klass* sib = super->subklass();

    while (sib->next_sibling() != this) {

      sib = sib->next_sibling();

    };

    sib->set_next_sibling(_next_sibling);

  }

}

void Klass::follow_weak_klass_links( BoolObjectClosure* is_alive, OopClosure* keep_alive) {

  // This klass is alive but the subklass and siblings are not followed/updated.

  // We update the subklass link and the subklass' sibling links here.

  // Our own sibling link will be updated by our superclass (which must be alive

  // since we are).

  assert(is_alive->do_object_b(as_klassOop()), "just checking, this should be live");

  if (ClassUnloading) {

    klassOop sub = subklass_oop();

    if (sub != NULL && !is_alive->do_object_b(sub)) {

      // first subklass not alive, find first one alive

      do {

#ifndef PRODUCT

        if (TraceClassUnloading && WizardMode) {

          ResourceMark rm;

          tty->print_cr("[Unlinking class (subclass) %s]", sub->klass_part()->external_name());

        }

#endif

        sub = sub->klass_part()->next_sibling_oop();

      } while (sub != NULL && !is_alive->do_object_b(sub));

      set_subklass(sub);

    }

    // now update the subklass' sibling list

    while (sub != NULL) {

      klassOop next = sub->klass_part()->next_sibling_oop();

      if (next != NULL && !is_alive->do_object_b(next)) {

        // first sibling not alive, find first one alive

        do {

#ifndef PRODUCT

          if (TraceClassUnloading && WizardMode) {

            ResourceMark rm;

            tty->print_cr("[Unlinking class (sibling) %s]", next->klass_part()->external_name());

          }

#endif

          next = next->klass_part()->next_sibling_oop();

        } while (next != NULL && !is_alive->do_object_b(next));

        sub->klass_part()->set_next_sibling(next);

      }

      sub = next;

    }

  } else {

    // Always follow subklass and sibling link. This will prevent any klasses from

    // being unloaded (all classes are transitively linked from java.lang.Object).

    keep_alive->do_oop(adr_subklass());

    keep_alive->do_oop(adr_next_sibling());

  }

}

void Klass::remove_unshareable_info() {

  if (oop_is_instance()) {

    instanceKlass* ik = (instanceKlass*)this;

    if (ik->is_linked()) {

      ik->unlink_class();

    }

  }

  // Clear the Java vtable if the oop has one.

  // The vtable isn't shareable because it's in the wrong order wrt the methods

  // once the method names get moved and resorted.

  klassVtable* vt = vtable();

  if (vt != NULL) {

    assert(oop_is_instance() || oop_is_array(), "nothing else has vtable");

    vt->clear_vtable();

  }

  set_subklass(NULL);

  set_next_sibling(NULL);

}

void Klass::shared_symbols_iterate(SymbolClosure* closure) {

  closure->do_symbol(&_name);

}

klassOop Klass::array_klass_or_null(int rank) {

  EXCEPTION_MARK;

  // No exception can be thrown by array_klass_impl when called with or_null == true.

  // (In anycase, the execption mark will fail if it do so)

  return array_klass_impl(true, rank, THREAD);

}

klassOop Klass::array_klass_or_null() {

  EXCEPTION_MARK;

  // No exception can be thrown by array_klass_impl when called with or_null == true.

  // (In anycase, the execption mark will fail if it do so)

  return array_klass_impl(true, THREAD);

}

klassOop Klass::array_klass_impl(bool or_null, int rank, TRAPS) {

  fatal("array_klass should be dispatched to instanceKlass, objArrayKlass or typeArrayKlass");

  return NULL;

}

klassOop Klass::array_klass_impl(bool or_null, TRAPS) {

  fatal("array_klass should be dispatched to instanceKlass, objArrayKlass or typeArrayKlass");

  return NULL;

}

void Klass::with_array_klasses_do(void f(klassOop k)) {

  f(as_klassOop());

}

const char* Klass::external_name() const {

  if (oop_is_instance()) {

    instanceKlass* ik = (instanceKlass*) this;

    if (ik->is_anonymous()) {

      assert(EnableInvokeDynamic, "");

      intptr_t hash = ik->java_mirror()->identity_hash();

      char     hash_buf[40];

      sprintf(hash_buf, "/" UINTX_FORMAT, (uintx)hash);

      size_t   hash_len = strlen(hash_buf);

      size_t result_len = name()->utf8_length();

      char*  result     = NEW_RESOURCE_ARRAY(char, result_len + hash_len + 1);

      name()->as_klass_external_name(result, (int) result_len + 1);

      assert(strlen(result) == result_len, "");

      strcpy(result + result_len, hash_buf);

      assert(strlen(result) == result_len + hash_len, "");