/*

 * Copyright (c) 2014, 2017, 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.

 *

 */

#ifndef SHARE_VM_MEMORY_ITERATOR_INLINE_HPP

#define SHARE_VM_MEMORY_ITERATOR_INLINE_HPP

#include "classfile/classLoaderData.hpp"

#include "memory/iterator.hpp"

#include "oops/access.inline.hpp"

#include "oops/compressedOops.inline.hpp"

#include "oops/klass.hpp"

#include "oops/instanceKlass.inline.hpp"

#include "oops/instanceMirrorKlass.inline.hpp"

#include "oops/instanceClassLoaderKlass.inline.hpp"

#include "oops/instanceRefKlass.inline.hpp"

#include "oops/objArrayKlass.inline.hpp"

#include "oops/typeArrayKlass.inline.hpp"

#include "utilities/debug.hpp"

inline void MetadataVisitingOopIterateClosure::do_cld(ClassLoaderData* cld) {

  cld->oops_do(this, ClassLoaderData::_claim_strong);

}

inline void MetadataVisitingOopIterateClosure::do_klass(Klass* k) {

  ClassLoaderData* cld = k->class_loader_data();

  MetadataVisitingOopIterateClosure::do_cld(cld);

}

#ifdef ASSERT

// This verification is applied to all visited oops.

// The closures can turn is off by overriding should_verify_oops().

template <typename T>

void OopIterateClosure::verify(T* p) {

  if (should_verify_oops()) {

    T heap_oop = RawAccess<>::oop_load(p);

    if (!CompressedOops::is_null(heap_oop)) {

      oop o = CompressedOops::decode_not_null(heap_oop);

      assert(Universe::heap()->is_in_closed_subset(o),

             "should be in closed *p " PTR_FORMAT " " PTR_FORMAT, p2i(p), p2i(o));

    }

  }

}

#endif

// Implementation of the non-virtual do_oop dispatch.

//

// The same implementation is used for do_metadata, do_klass, and do_cld.

//

// Preconditions:

//  - Base has a pure virtual do_oop

//  - Only one of the classes in the inheritance chain from OopClosureType to

//    Base implements do_oop.

//

// Given the preconditions:

//  - If &OopClosureType::do_oop is resolved to &Base::do_oop, then there is no

//    implementation of do_oop between Base and OopClosureType. However, there

//    must be one implementation in one of the subclasses of OopClosureType.

//    In this case we take the virtual call.

//

//  - Conversely, if &OopClosureType::do_oop is not resolved to &Base::do_oop,

//    then we've found the one and only concrete implementation. In this case we

//    take a non-virtual call.

//

// Because of this it's clear when we should call the virtual call and

//   when the non-virtual call should be made.

//

// The way we find if &OopClosureType::do_oop is resolved to &Base::do_oop is to

//   check if the resulting type of the class of a member-function pointer to

//   &OopClosureType::do_oop is equal to the type of the class of a

//   &Base::do_oop member-function pointer. Template parameter deduction is used

//   to find these types, and then the IsSame trait is used to check if they are

//   equal. Finally, SFINAE is used to select the appropriate implementation.

//

// Template parameters:

//   T              - narrowOop or oop

//   Receiver       - the resolved type of the class of the

//                    &OopClosureType::do_oop member-function pointer. That is,

//                    the klass with the do_oop member function.

//   Base           - klass with the pure virtual do_oop member function.

//   OopClosureType - The dynamic closure type

//

// Parameters:

//   closure - The closure to call

//   p       - The oop (or narrowOop) field to pass to the closure

template <typename T, typename Receiver, typename Base, typename OopClosureType>

static typename EnableIf<IsSame<Receiver, Base>::value, void>::type

call_do_oop(void (Receiver::*)(T*), void (Base::*)(T*), OopClosureType* closure, T* p) {

  closure->do_oop(p);

}

template <typename T, typename Receiver, typename Base, typename OopClosureType>

static typename EnableIf<!IsSame<Receiver, Base>::value, void>::type

call_do_oop(void (Receiver::*)(T*), void (Base::*)(T*), OopClosureType* closure, T* p) {

  // Sanity check

  STATIC_ASSERT((!IsSame<OopClosureType, OopIterateClosure>::value));

  closure->OopClosureType::do_oop(p);

}

template <typename OopClosureType, typename T>

inline void Devirtualizer::do_oop_no_verify(OopClosureType* closure, T* p) {

  call_do_oop<T>(&OopClosureType::do_oop, &OopClosure::do_oop, closure, p);

}

template <typename OopClosureType, typename T>

inline void Devirtualizer::do_oop(OopClosureType* closure, T* p) {

  debug_only(closure->verify(p));

  do_oop_no_verify(closure, p);

}

// Implementation of the non-virtual do_metadata dispatch.

template <typename Receiver, typename Base, typename OopClosureType>

static typename EnableIf<IsSame<Receiver, Base>::value, bool>::type

call_do_metadata(bool (Receiver::*)(), bool (Base::*)(), OopClosureType* closure) {

  return closure->do_metadata();

}

template <typename Receiver, typename Base, typename OopClosureType>

static typename EnableIf<!IsSame<Receiver, Base>::value, bool>::type

call_do_metadata(bool (Receiver::*)(), bool (Base::*)(), OopClosureType* closure) {

  return closure->OopClosureType::do_metadata();

}

template <typename OopClosureType>

inline bool Devirtualizer::do_metadata(OopClosureType* closure) {

  return call_do_metadata(&OopClosureType::do_metadata, &OopIterateClosure::do_metadata, closure);

}

// Implementation of the non-virtual do_klass dispatch.

template <typename Receiver, typename Base, typename OopClosureType>

static typename EnableIf<IsSame<Receiver, Base>::value, void>::type

call_do_klass(void (Receiver::*)(Klass*), void (Base::*)(Klass*), OopClosureType* closure, Klass* k) {

  closure->do_klass(k);

}

template <typename Receiver, typename Base, typename OopClosureType>

static typename EnableIf<!IsSame<Receiver, Base>::value, void>::type

call_do_klass(void (Receiver::*)(Klass*), void (Base::*)(Klass*), OopClosureType* closure, Klass* k) {

  closure->OopClosureType::do_klass(k);

}

template <typename OopClosureType>

inline void Devirtualizer::do_klass(OopClosureType* closure, Klass* k) {

  call_do_klass(&OopClosureType::do_klass, &OopIterateClosure::do_klass, closure, k);

}

// Implementation of the non-virtual do_cld dispatch.

template <typename Receiver, typename Base, typename OopClosureType>

static typename EnableIf<IsSame<Receiver, Base>::value, void>::type

call_do_cld(void (Receiver::*)(ClassLoaderData*), void (Base::*)(ClassLoaderData*), OopClosureType* closure, ClassLoaderData* cld) {

  closure->do_cld(cld);

}

template <typename Receiver, typename Base, typename OopClosureType>

static typename EnableIf<!IsSame<Receiver, Base>::value, void>::type

call_do_cld(void (Receiver::*)(ClassLoaderData*), void (Base::*)(ClassLoaderData*), OopClosureType* closure, ClassLoaderData* cld) {

  closure->OopClosureType::do_cld(cld);

}

template <typename OopClosureType>

void Devirtualizer::do_cld(OopClosureType* closure, ClassLoaderData* cld) {

  call_do_cld(&OopClosureType::do_cld, &OopIterateClosure::do_cld, closure, cld);

}

// Dispatch table implementation for *Klass::oop_oop_iterate

//

// It allows for a single call to do a multi-dispatch to an optimized version

//   of oop_oop_iterate that statically know all these types:

//   - OopClosureType    : static type give at call site

//   - Klass*            : dynamic to static type through Klass::id() -> table index

//   - UseCompressedOops : dynamic to static value determined once

//

// when users call obj->oop_iterate(&cl).

//

// oopDesc::oop_iterate() calls OopOopIterateDispatch::function(klass)(cl, obj, klass),

//   which dispatches to an optimized version of

//   [Instance, ObjArry, etc]Klass::oop_oop_iterate(oop, OopClosureType)

//

// OopClosureType :

//   If OopClosureType has an implementation of do_oop (and do_metadata et.al.),

//   then the static type of OopClosureType will be used to allow inlining of

//   do_oop (even though do_oop is virtual). Otherwise, a virtual call will be

//   used when calling do_oop.

//

// Klass* :

//   A table mapping from *Klass::ID to function is setup. This happens once

//   when the program starts, when the static _table instance is initialized for

//   the OopOopIterateDispatch specialized with the OopClosureType.

//

// UseCompressedOops :

//   Initially the table is populated with an init function, and not the actual

//   oop_oop_iterate function. This is done, so that the first time we dispatch

//   through the init function we check what the value of UseCompressedOops

//   became, and use that to determine if we should install an optimized

//   narrowOop version or optimized oop version of oop_oop_iterate. The appropriate

//   oop_oop_iterate function replaces the init function in the table, and

//   succeeding calls will jump directly to oop_oop_iterate.

template <typename OopClosureType>

class OopOopIterateDispatch : public AllStatic {

private:

  class Table {

  private:

    template <typename KlassType, typename T>

    static void oop_oop_iterate(OopClosureType* cl, oop obj, Klass* k) {

      ((KlassType*)k)->KlassType::template oop_oop_iterate<T>(obj, cl);

    }

    template <typename KlassType>

    static void init(OopClosureType* cl, oop obj, Klass* k) {

      OopOopIterateDispatch<OopClosureType>::_table.set_resolve_function_and_execute<KlassType>(cl, obj, k);

    }

    template <typename KlassType>

    void set_init_function() {

      _function[KlassType::ID] = &init<KlassType>;

    }

    template <typename KlassType>

    void set_resolve_function() {

      // Size requirement to prevent word tearing

      // when functions pointers are updated.

      STATIC_ASSERT(sizeof(_function[0]) == sizeof(void*));

      if (UseCompressedOops) {

        _function[KlassType::ID] = &oop_oop_iterate<KlassType, narrowOop>;

      } else {

        _function[KlassType::ID] = &oop_oop_iterate<KlassType, oop>;

      }

    }

    template <typename KlassType>

    void set_resolve_function_and_execute(OopClosureType* cl, oop obj, Klass* k) {

      set_resolve_function<KlassType>();

      _function[KlassType::ID](cl, obj, k);

    }

  public:

    void (*_function[KLASS_ID_COUNT])(OopClosureType*, oop, Klass*);

    Table(){

      set_init_function<InstanceKlass>();

      set_init_function<InstanceRefKlass>();

      set_init_function<InstanceMirrorKlass>();

      set_init_function<InstanceClassLoaderKlass>();

      set_init_function<ObjArrayKlass>();

      set_init_function<TypeArrayKlass>();

    }

  };

  static Table _table;

public:

  static void (*function(Klass* klass))(OopClosureType*, oop, Klass*) {

    return _table._function[klass->id()];

  }

};

template <typename OopClosureType>

typename OopOopIterateDispatch<OopClosureType>::Table OopOopIterateDispatch<OopClosureType>::_table;

template <typename OopClosureType>

class OopOopIterateBoundedDispatch {

private:

  class Table {

  private:

    template <typename KlassType, typename T>

    static void oop_oop_iterate_bounded(OopClosureType* cl, oop obj, Klass* k, MemRegion mr) {

      ((KlassType*)k)->KlassType::template oop_oop_iterate_bounded<T>(obj, cl, mr);

    }

    template <typename KlassType>

    static void init(OopClosureType* cl, oop obj, Klass* k, MemRegion mr) {

      OopOopIterateBoundedDispatch<OopClosureType>::_table.set_resolve_function_and_execute<KlassType>(cl, obj, k, mr);

    }

    template <typename KlassType>

    void set_init_function() {

      _function[KlassType::ID] = &init<KlassType>;

    }

    template <typename KlassType>

    void set_resolve_function() {

      if (UseCompressedOops) {

        _function[KlassType::ID] = &oop_oop_iterate_bounded<KlassType, narrowOop>;

      } else {

        _function[KlassType::ID] = &oop_oop_iterate_bounded<KlassType, oop>;

      }

    }

    template <typename KlassType>

    void set_resolve_function_and_execute(OopClosureType* cl, oop obj, Klass* k, MemRegion mr) {

      set_resolve_function<KlassType>();

      _function[KlassType::ID](cl, obj, k, mr);

    }

  public:

    void (*_function[KLASS_ID_COUNT])(OopClosureType*, oop, Klass*, MemRegion);

    Table(){

      set_init_function<InstanceKlass>();

      set_init_function<InstanceRefKlass>();

      set_init_function<InstanceMirrorKlass>();

      set_init_function<InstanceClassLoaderKlass>();

      set_init_function<ObjArrayKlass>();

      set_init_function<TypeArrayKlass>();

    }

  };

  static Table _table;

public:

  static void (*function(Klass* klass))(OopClosureType*, oop, Klass*, MemRegion) {

    return _table._function[klass->id()];

  }

};

template <typename OopClosureType>

typename OopOopIterateBoundedDispatch<OopClosureType>::Table OopOopIterateBoundedDispatch<OopClosureType>::_table;

template <typename OopClosureType>

class OopOopIterateBackwardsDispatch {

private:

  class Table {

  private:

    template <typename KlassType, typename T>

    static void oop_oop_iterate_backwards(OopClosureType* cl, oop obj, Klass* k) {

      ((KlassType*)k)->KlassType::template oop_oop_iterate_reverse<T>(obj, cl);

    }

    template <typename KlassType>

    static void init(OopClosureType* cl, oop obj, Klass* k) {

      OopOopIterateBackwardsDispatch<OopClosureType>::_table.set_resolve_function_and_execute<KlassType>(cl, obj, k);

    }

    template <typename KlassType>

    void set_init_function() {

      _function[KlassType::ID] = &init<KlassType>;

    }

    template <typename KlassType>

    void set_resolve_function() {

      if (UseCompressedOops) {

        _function[KlassType::ID] = &oop_oop_iterate_backwards<KlassType, narrowOop>;

      } else {

        _function[KlassType::ID] = &oop_oop_iterate_backwards<KlassType, oop>;

      }

    }

    template <typename KlassType>

    void set_resolve_function_and_execute(OopClosureType* cl, oop obj, Klass* k) {

      set_resolve_function<KlassType>();

      _function[KlassType::ID](cl, obj, k);

    }

  public:

    void (*_function[KLASS_ID_COUNT])(OopClosureType*, oop, Klass*);

    Table(){

      set_init_function<InstanceKlass>();

      set_init_function<InstanceRefKlass>();

      set_init_function<InstanceMirrorKlass>();

      set_init_function<InstanceClassLoaderKlass>();

      set_init_function<ObjArrayKlass>();

      set_init_function<TypeArrayKlass>();

    }

  };

  static Table _table;

public:

  static void (*function(Klass* klass))(OopClosureType*, oop, Klass*) {

    return _table._function[klass->id()];

  }

};

template <typename OopClosureType>

typename OopOopIterateBackwardsDispatch<OopClosureType>::Table OopOopIterateBackwardsDispatch<OopClosureType>::_table;

template <typename OopClosureType>

void OopIteratorClosureDispatch::oop_oop_iterate(OopClosureType* cl, oop obj, Klass* klass) {

  OopOopIterateDispatch<OopClosureType>::function(klass)(cl, obj, klass);

}

template <typename OopClosureType>

void OopIteratorClosureDispatch::oop_oop_iterate(OopClosureType* cl, oop obj, Klass* klass, MemRegion mr) {

  OopOopIterateBoundedDispatch<OopClosureType>::function(klass)(cl, obj, klass, mr);

}

template <typename OopClosureType>

void OopIteratorClosureDispatch::oop_oop_iterate_backwards(OopClosureType* cl, oop obj, Klass* klass) {

  OopOopIterateBackwardsDispatch<OopClosureType>::function(klass)(cl, obj, klass);

}

#endif // SHARE_VM_MEMORY_ITERATOR_INLINE_HPP