/*
 * Copyright (c) 2013, 2015, Red Hat, Inc. and/or its affiliates.
 *
 * 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_GC_SHENANDOAH_SHENANDOAHBARRIERSET_HPP
#define SHARE_VM_GC_SHENANDOAH_SHENANDOAHBARRIERSET_HPP

#include "gc/shenandoah/shenandoahHeap.hpp"
#include "gc/shared/barrierSet.hpp"

class ShenandoahBarrierSet: public BarrierSet {
private:

  static inline oop get_shenandoah_forwardee_helper(oop p) {
    assert(UseShenandoahGC, "must only be called when Shenandoah is used.");
    assert(Universe::heap()->is_in(p), "We shouldn't be calling this on objects not in the heap");
    oop forwardee;
#ifdef ASSERT
    if (ShenandoahVerifyReadsToFromSpace) {
      ShenandoahHeap* heap = (ShenandoahHeap *) Universe::heap();
      ShenandoahHeapRegion* region = heap->heap_region_containing(p);
      {
        region->memProtectionOff();
        forwardee = oop( *((HeapWord**) ((HeapWord*) p) - 1));
        region->memProtectionOn();
      }
    } else {
      forwardee = oop( *((HeapWord**) ((HeapWord*) p) - 1));
    }
#else
    forwardee = oop( *((HeapWord**) ((HeapWord*) p) - 1));
#endif
    return forwardee;
  }

public:

  ShenandoahBarrierSet();

  void print_on(outputStream* st) const;

  bool is_a(BarrierSet::Name bsn);

  bool has_read_prim_array_opt();
  bool has_read_prim_barrier();
  bool has_read_ref_array_opt();
  bool has_read_ref_barrier();
  bool has_read_region_opt();
  bool has_write_prim_array_opt();
  bool has_write_prim_barrier();
  bool has_write_ref_array_opt();
  bool has_write_ref_barrier();
  bool has_write_ref_pre_barrier();
  bool has_write_region_opt();
  bool is_aligned(HeapWord* hw);
  void read_prim_array(MemRegion mr);
  void read_prim_field(HeapWord* hw, size_t s);
  bool read_prim_needs_barrier(HeapWord* hw, size_t s);
  void read_ref_array(MemRegion mr);

  void read_ref_field(void* v);

  bool read_ref_needs_barrier(void* v);
  void read_region(MemRegion mr);
  void resize_covered_region(MemRegion mr);
  void write_prim_array(MemRegion mr);
  void write_prim_field(HeapWord* hw, size_t s , juint x, juint y);
  bool write_prim_needs_barrier(HeapWord* hw, size_t s, juint x, juint y);
  void write_ref_array_work(MemRegion mr);

  template <class T> void
  write_ref_array_pre_work(T* dst, int count);

  void write_ref_array_pre(oop* dst, int count, bool dest_uninitialized);

  void write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized);


  template <class T> static void write_ref_field_pre_static(T* field, oop newVal);

  // We export this to make it available in cases where the static
  // type of the barrier set is known.  Note that it is non-virtual.
  template <class T> inline void inline_write_ref_field_pre(T* field, oop newVal);

  // These are the more general virtual versions.
  void write_ref_field_pre_work(oop* field, oop new_val);
  void write_ref_field_pre_work(narrowOop* field, oop new_val);
  void write_ref_field_pre_work(void* field, oop new_val);

  void write_ref_field_work(void* v, oop o, bool release = false);
  void write_region_work(MemRegion mr);

  virtual oop resolve_oop(oop src);

  template <class T>
  static inline oop resolve_and_update_oop_static(T p, oop obj) {
    oop forw = ShenandoahBarrierSet::resolve_oop_static_not_null(obj);
    if (forw != obj) {
      obj = forw;
      oopDesc::encode_store_heap_oop_not_null(p, obj);
    }
    return obj;
  }

  static inline oop resolve_oop_static_not_null(oop p) {
    assert(p != NULL, "Must be NULL checked");

    oop result = get_shenandoah_forwardee_helper(p);

    if (result != NULL) {
#ifdef ASSERT
      if (result != p) {
        oop second_forwarding = get_shenandoah_forwardee_helper(result);

        // We should never be forwarded more than once.
        if (result != second_forwarding) {
          ShenandoahHeap* sh = (ShenandoahHeap*) Universe::heap();
          tty->print("first reference "PTR_FORMAT" is in heap region:\n", p2i((HeapWord*) p));
          sh->heap_region_containing(p)->print();
          tty->print("first_forwarding "PTR_FORMAT" is in heap region:\n", p2i((HeapWord*) result));
          sh->heap_region_containing(result)->print();
          tty->print("final reference "PTR_FORMAT" is in heap region:\n", p2i((HeapWord*) second_forwarding));
          sh->heap_region_containing(second_forwarding)->print();
          assert(get_shenandoah_forwardee_helper(result) == result, "Only one fowarding per customer");
        }
      }
#endif
      if (! ShenandoahVerifyReadsToFromSpace) {
	// is_oop() would trigger a SEGFAULT when we're checking from-space-access.
	assert(ShenandoahHeap::heap()->is_in(result) && result->is_oop(), "resolved oop must be a valid oop in the heap");
      }
    }
    return result;
  }

  static inline oop resolve_oop_static(oop p) {
    if (((HeapWord*) p) != NULL) {
      return resolve_oop_static_not_null(p);
    } else {
      return p;
    }
  }

  static inline oop resolve_oop_static_no_check(oop p) {
    if (((HeapWord*) p) != NULL) {
      return get_shenandoah_forwardee_helper(p);
    } else {
      return p;
    }
  }


  oop resolve_and_maybe_copy_oopHelper(oop src);
  oop resolve_and_maybe_copy_oop_work(oop src);
  oop resolve_and_maybe_copy_oop_work2(oop src);
  virtual oop resolve_and_maybe_copy_oop(oop src);

  static oopDesc* resolve_and_maybe_copy_oop_c2(oopDesc* src);
  static oopDesc* resolve_and_maybe_copy_oop_interp(oopDesc* src);
  static oopDesc* resolve_and_maybe_copy_oop_c1(JavaThread* thread, oopDesc* src);

private:
  bool need_update_refs_barrier();

#ifndef CC_INTERP
public:
  virtual void interpreter_read_barrier(MacroAssembler* masm, Register dst);
  virtual void interpreter_read_barrier_not_null(MacroAssembler* masm, Register dst);
  void interpreter_write_barrier(MacroAssembler* masm, Register dst);

private:
  void compile_resolve_oop_runtime(MacroAssembler* masm, Register dst);

#endif
};

class ShenandoahMarkCompactBarrierSet : public ShenandoahBarrierSet {

   oop resolve_oop(oop src) {
     return src;
   }
   oop maybe_resolve_oop(oop src) {
     return src;
   }
};

#endif //SHARE_VM_GC_SHENANDOAH_SHENANDOAHBARRIERSET_HPP