/*
 * Copyright (c) 2018, 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.
 *
 */

#include "gc/shenandoah/c2/shenandoahLRBBarrierSetC2.hpp"
#include "gc/shenandoah/c2/shenandoahSupport.hpp"
#include "opto/graphKit.hpp"
#include "opto/narrowptrnode.hpp"

Node* ShenandoahLRBBarrierSetC2::store_at_resolved(C2Access& access, C2AccessValue& val) const {
  DecoratorSet decorators = access.decorators();
  GraphKit* kit = access.kit();

  const TypePtr* adr_type = access.addr().type();
  Node* adr = access.addr().node();

  bool anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
  bool on_heap = (decorators & IN_HEAP) != 0;

  if (!access.is_oop() || (!on_heap && !anonymous)) {
    return ShenandoahBaseBarrierSetC2::store_at_resolved(access, val);
  }

  uint adr_idx = kit->C->get_alias_index(adr_type);
  assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
  val.set_node(shenandoah_enqueue_barrier(kit, val.node()));
  shenandoah_write_barrier_pre(kit, true /* do_load */, /*kit->control(),*/ access.base(), adr, adr_idx, val.node(),
                               static_cast<const TypeOopPtr*>(val.type()), NULL /* pre_val */, access.type());
  return ShenandoahBaseBarrierSetC2::store_at_resolved(access, val);
}

Node* ShenandoahLRBBarrierSetC2::load_at_resolved(C2Access& access, const Type* val_type) const {
  DecoratorSet decorators = access.decorators();
  GraphKit* kit = access.kit();

  Node* adr = access.addr().node();
  Node* obj = access.base();

  bool mismatched = (decorators & C2_MISMATCHED) != 0;
  bool unknown = (decorators & ON_UNKNOWN_OOP_REF) != 0;
  bool on_heap = (decorators & IN_HEAP) != 0;
  bool on_weak = (decorators & ON_WEAK_OOP_REF) != 0;
  bool is_unordered = (decorators & MO_UNORDERED) != 0;
  bool need_cpu_mem_bar = !is_unordered || mismatched || !on_heap;

  Node* offset = adr->is_AddP() ? adr->in(AddPNode::Offset) : kit->top();
  Node* load = ShenandoahBaseBarrierSetC2::load_at_resolved(access, val_type);

  if (access.is_oop()) {
    load = shenandoah_write_barrier(access.kit(), load);
  }

  // If we are reading the value of the referent field of a Reference
  // object (either by using Unsafe directly or through reflection)
  // then, if SATB is enabled, we need to record the referent in an
  // SATB log buffer using the pre-barrier mechanism.
  // Also we need to add memory barrier to prevent commoning reads
  // from this field across safepoint since GC can change its value.
  bool need_read_barrier = ShenandoahKeepAliveBarrier &&
                           (on_heap && (on_weak || (unknown && offset != kit->top() && obj != kit->top())));

  if (!access.is_oop() || !need_read_barrier) {
    return load;
  }

  if (on_weak) {
    // Use the pre-barrier to record the value in the referent field
    satb_write_barrier_pre(kit, false /* do_load */,
                           NULL /* obj */, NULL /* adr */, max_juint /* alias_idx */, NULL /* val */, NULL /* val_type */,
                           load /* pre_val */, T_OBJECT);
    // Add memory barrier to prevent commoning reads from this field
    // across safepoint since GC can change its value.
    kit->insert_mem_bar(Op_MemBarCPUOrder);
  } else if (unknown) {
    // We do not require a mem bar inside pre_barrier if need_mem_bar
    // is set: the barriers would be emitted by us.
    insert_pre_barrier(kit, obj, offset, load, !need_cpu_mem_bar);
  }

  return load;
}

Node* ShenandoahLRBBarrierSetC2::atomic_cmpxchg_val_at_resolved(C2AtomicAccess& access, Node* expected_val,
                                                                Node* new_val, const Type* value_type) const {
  GraphKit* kit = access.kit();
  if (access.is_oop()) {
    new_val = shenandoah_enqueue_barrier(kit, new_val);
    shenandoah_write_barrier_pre(kit, false /* do_load */,
                                 NULL, NULL, max_juint, NULL, NULL,
                                 expected_val /* pre_val */, T_OBJECT);

    MemNode::MemOrd mo = access.mem_node_mo();
    Node* mem = access.memory();
    Node* adr = access.addr().node();
    const TypePtr* adr_type = access.addr().type();
    Node* load_store = NULL;

#ifdef _LP64
    if (adr->bottom_type()->is_ptr_to_narrowoop()) {
      Node *newval_enc = kit->gvn().transform(new EncodePNode(new_val, new_val->bottom_type()->make_narrowoop()));
      Node *oldval_enc = kit->gvn().transform(new EncodePNode(expected_val, expected_val->bottom_type()->make_narrowoop()));
      load_store = kit->gvn().transform(new ShenandoahCompareAndExchangeNNode(kit->control(), mem, adr, newval_enc, oldval_enc, adr_type, value_type->make_narrowoop(), mo));
    } else
#endif
    {
      load_store = kit->gvn().transform(new ShenandoahCompareAndExchangePNode(kit->control(), mem, adr, new_val, expected_val, adr_type, value_type->is_oopptr(), mo));
    }

    access.set_raw_access(load_store);
    pin_atomic_op(access);

#ifdef _LP64
    if (adr->bottom_type()->is_ptr_to_narrowoop()) {
      load_store = kit->gvn().transform(new DecodeNNode(load_store, load_store->get_ptr_type()));
    }
#endif
    load_store = shenandoah_write_barrier(kit, load_store);
    return load_store;
  }
  return ShenandoahBaseBarrierSetC2::atomic_cmpxchg_val_at_resolved(access, expected_val, new_val, value_type);

}

Node* ShenandoahLRBBarrierSetC2::atomic_cmpxchg_bool_at_resolved(C2AtomicAccess& access, Node* expected_val,
                                                                 Node* new_val, const Type* value_type) const {
  GraphKit* kit = access.kit();
  if (access.is_oop()) {
    new_val = shenandoah_enqueue_barrier(kit, new_val);
    shenandoah_write_barrier_pre(kit, false /* do_load */,
                                 NULL, NULL, max_juint, NULL, NULL,
                                 expected_val /* pre_val */, T_OBJECT);
    DecoratorSet decorators = access.decorators();
    MemNode::MemOrd mo = access.mem_node_mo();
    Node* mem = access.memory();
    bool is_weak_cas = (decorators & C2_WEAK_CMPXCHG) != 0;
    Node* load_store = NULL;
    Node* adr = access.addr().node();
#ifdef _LP64
    if (adr->bottom_type()->is_ptr_to_narrowoop()) {
      Node *newval_enc = kit->gvn().transform(new EncodePNode(new_val, new_val->bottom_type()->make_narrowoop()));
      Node *oldval_enc = kit->gvn().transform(new EncodePNode(expected_val, expected_val->bottom_type()->make_narrowoop()));
      if (is_weak_cas) {
        load_store = kit->gvn().transform(new ShenandoahWeakCompareAndSwapNNode(kit->control(), mem, adr, newval_enc, oldval_enc, mo));
      } else {
        load_store = kit->gvn().transform(new ShenandoahCompareAndSwapNNode(kit->control(), mem, adr, newval_enc, oldval_enc, mo));
      }
    } else
#endif
    {
      if (is_weak_cas) {
        load_store = kit->gvn().transform(new ShenandoahWeakCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
      } else {
        load_store = kit->gvn().transform(new ShenandoahCompareAndSwapPNode(kit->control(), mem, adr, new_val, expected_val, mo));
      }
    }
    access.set_raw_access(load_store);
    pin_atomic_op(access);
    return load_store;
  }
  return ShenandoahBaseBarrierSetC2::atomic_cmpxchg_bool_at_resolved(access, expected_val, new_val, value_type);
}

Node* ShenandoahLRBBarrierSetC2::atomic_xchg_at_resolved(C2AtomicAccess& access, Node* new_val, const Type* value_type) const {
  GraphKit* kit = access.kit();
  if (access.is_oop()) {
    new_val = shenandoah_enqueue_barrier(kit, new_val);
  }
  Node* result = ShenandoahBaseBarrierSetC2::atomic_xchg_at_resolved(access, new_val, value_type);
  if (access.is_oop()) {
    shenandoah_write_barrier_pre(kit, false /* do_load */,
                                 NULL, NULL, max_juint, NULL, NULL,
                                 result /* pre_val */, T_OBJECT);
    result = shenandoah_write_barrier(kit, result);
  }
  return result;
}