/*

 * Copyright (c) 2018, Red Hat, Inc. All rights reserved.

 *

 * 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 "c1/c1_IR.hpp"

#include "gc/shared/satbMarkQueue.hpp"

#include "gc/shenandoah/shenandoahBarrierSetAssembler.hpp"

#include "gc/shenandoah/shenandoahHeap.hpp"

#include "gc/shenandoah/shenandoahHeapRegion.hpp"

#include "gc/shenandoah/shenandoahThreadLocalData.hpp"

#include "gc/shenandoah/c1/shenandoahBarrierSetC1.hpp"

#ifdef ASSERT

#define __ gen->lir(__FILE__, __LINE__)->

#else

#define __ gen->lir()->

#endif

void ShenandoahPreBarrierStub::emit_code(LIR_Assembler* ce) {

  ShenandoahBarrierSetAssembler* bs = (ShenandoahBarrierSetAssembler*)BarrierSet::barrier_set()->barrier_set_assembler();

  bs->gen_pre_barrier_stub(ce, this);

}

void ShenandoahLoadReferenceBarrierStub::emit_code(LIR_Assembler* ce) {

  ShenandoahBarrierSetAssembler* bs = (ShenandoahBarrierSetAssembler*)BarrierSet::barrier_set()->barrier_set_assembler();

  bs->gen_load_reference_barrier_stub(ce, this);

}

void ShenandoahBarrierSetC1::pre_barrier(LIRGenerator* gen, CodeEmitInfo* info, DecoratorSet decorators, LIR_Opr addr_opr, LIR_Opr pre_val) {

  // First we test whether marking is in progress.

  BasicType flag_type;

  bool patch = (decorators & C1_NEEDS_PATCHING) != 0;

  bool do_load = pre_val == LIR_OprFact::illegalOpr;

  if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {

    flag_type = T_INT;

  } else {

    guarantee(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1,

              "Assumption");

    // Use unsigned type T_BOOLEAN here rather than signed T_BYTE since some platforms, eg. ARM,

    // need to use unsigned instructions to use the large offset to load the satb_mark_queue.

    flag_type = T_BOOLEAN;

  }

  LIR_Opr thrd = gen->getThreadPointer();

  LIR_Address* mark_active_flag_addr =

    new LIR_Address(thrd,

                    in_bytes(ShenandoahThreadLocalData::satb_mark_queue_active_offset()),

                    flag_type);

  // Read the marking-in-progress flag.

  LIR_Opr flag_val = gen->new_register(T_INT);

  __ load(mark_active_flag_addr, flag_val);

  __ cmp(lir_cond_notEqual, flag_val, LIR_OprFact::intConst(0));

  LIR_PatchCode pre_val_patch_code = lir_patch_none;

  CodeStub* slow;

  if (do_load) {

    assert(pre_val == LIR_OprFact::illegalOpr, "sanity");

    assert(addr_opr != LIR_OprFact::illegalOpr, "sanity");

    if (patch)

      pre_val_patch_code = lir_patch_normal;

    pre_val = gen->new_register(T_OBJECT);

    if (!addr_opr->is_address()) {

      assert(addr_opr->is_register(), "must be");

      addr_opr = LIR_OprFact::address(new LIR_Address(addr_opr, T_OBJECT));

    }

    slow = new ShenandoahPreBarrierStub(addr_opr, pre_val, pre_val_patch_code, info ? new CodeEmitInfo(info) : NULL);

  } else {

    assert(addr_opr == LIR_OprFact::illegalOpr, "sanity");

    assert(pre_val->is_register(), "must be");

    assert(pre_val->type() == T_OBJECT, "must be an object");

    slow = new ShenandoahPreBarrierStub(pre_val);

  }

  __ branch(lir_cond_notEqual, T_INT, slow);

  __ branch_destination(slow->continuation());

}

LIR_Opr ShenandoahBarrierSetC1::load_reference_barrier(LIRGenerator* gen, LIR_Opr obj, CodeEmitInfo* info, bool need_null_check) {

  if (ShenandoahLoadRefBarrier) {

    return load_reference_barrier_impl(gen, obj, info, need_null_check);

  } else {

    return obj;

  }

}

LIR_Opr ShenandoahBarrierSetC1::load_reference_barrier_impl(LIRGenerator* gen, LIR_Opr obj, CodeEmitInfo* info, bool need_null_check) {

  assert(ShenandoahLoadRefBarrier, "Should be enabled");

  obj = ensure_in_register(gen, obj);

  assert(obj->is_register(), "must be a register at this point");

  LIR_Opr result = gen->new_register(T_OBJECT);

  __ move(obj, result);

  LIR_Opr thrd = gen->getThreadPointer();

  LIR_Address* active_flag_addr =

    new LIR_Address(thrd,

                    in_bytes(ShenandoahThreadLocalData::gc_state_offset()),

                    T_BYTE);

  // Read and check the gc-state-flag.

  LIR_Opr flag_val = gen->new_register(T_INT);

  __ load(active_flag_addr, flag_val);

  LIR_Opr mask = LIR_OprFact::intConst(ShenandoahHeap::HAS_FORWARDED |

                                       ShenandoahHeap::EVACUATION |

                                       ShenandoahHeap::TRAVERSAL);

  LIR_Opr mask_reg = gen->new_register(T_INT);

  __ move(mask, mask_reg);

  if (TwoOperandLIRForm) {

    __ logical_and(flag_val, mask_reg, flag_val);

  } else {

    LIR_Opr masked_flag = gen->new_register(T_INT);

    __ logical_and(flag_val, mask_reg, masked_flag);

    flag_val = masked_flag;

  }

  __ cmp(lir_cond_notEqual, flag_val, LIR_OprFact::intConst(0));

  CodeStub* slow = new ShenandoahLoadReferenceBarrierStub(obj, result, info ? new CodeEmitInfo(info) : NULL, need_null_check);

  __ branch(lir_cond_notEqual, T_INT, slow);

  __ branch_destination(slow->continuation());

  return result;

}

LIR_Opr ShenandoahBarrierSetC1::ensure_in_register(LIRGenerator* gen, LIR_Opr obj) {

  if (!obj->is_register()) {

    LIR_Opr obj_reg = gen->new_register(T_OBJECT);

    if (obj->is_constant()) {

      __ move(obj, obj_reg);

    } else {

      __ leal(obj, obj_reg);

    }

    obj = obj_reg;

  }

  return obj;

}

LIR_Opr ShenandoahBarrierSetC1::storeval_barrier(LIRGenerator* gen, LIR_Opr obj, CodeEmitInfo* info, DecoratorSet decorators) {

  if (ShenandoahStoreValEnqueueBarrier) {

    obj = ensure_in_register(gen, obj);

    pre_barrier(gen, info, decorators, LIR_OprFact::illegalOpr, obj);

  }

  return obj;

}

void ShenandoahBarrierSetC1::store_at_resolved(LIRAccess& access, LIR_Opr value) {

  if (access.is_oop()) {

    if (ShenandoahSATBBarrier) {

      pre_barrier(access.gen(), access.access_emit_info(), access.decorators(), access.resolved_addr(), LIR_OprFact::illegalOpr /* pre_val */);

    }

    value = storeval_barrier(access.gen(), value, access.access_emit_info(), access.decorators());

  }

  BarrierSetC1::store_at_resolved(access, value);

}

void ShenandoahBarrierSetC1::load_at_resolved(LIRAccess& access, LIR_Opr result) {

  if (!access.is_oop()) {

    BarrierSetC1::load_at_resolved(access, result);

    return;

  }

  LIRGenerator *gen = access.gen();

  if (ShenandoahLoadRefBarrier) {

    LIR_Opr tmp = gen->new_register(T_OBJECT);

    BarrierSetC1::load_at_resolved(access, tmp);

    tmp = load_reference_barrier(access.gen(), tmp, access.access_emit_info(), true);

    __ move(tmp, result);

  } else {

    BarrierSetC1::load_at_resolved(access, result);

  }

  if (ShenandoahKeepAliveBarrier) {

    DecoratorSet decorators = access.decorators();

    bool is_weak = (decorators & ON_WEAK_OOP_REF) != 0;

    bool is_phantom = (decorators & ON_PHANTOM_OOP_REF) != 0;

    bool is_anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;

    if (is_weak || is_phantom || is_anonymous) {

      // Register the value in the referent field with the pre-barrier

      LabelObj *Lcont_anonymous;

      if (is_anonymous) {

        Lcont_anonymous = new LabelObj();

        generate_referent_check(access, Lcont_anonymous);

      }

      pre_barrier(access.gen(), access.access_emit_info(), access.decorators(), LIR_OprFact::illegalOpr /* addr_opr */,

                  result /* pre_val */);

      if (is_anonymous) {

        __ branch_destination(Lcont_anonymous->label());

      }

    }

  }

}

class C1ShenandoahPreBarrierCodeGenClosure : public StubAssemblerCodeGenClosure {

  virtual OopMapSet* generate_code(StubAssembler* sasm) {

    ShenandoahBarrierSetAssembler* bs = (ShenandoahBarrierSetAssembler*)BarrierSet::barrier_set()->barrier_set_assembler();

    bs->generate_c1_pre_barrier_runtime_stub(sasm);

    return NULL;

  }

};

void ShenandoahBarrierSetC1::generate_c1_runtime_stubs(BufferBlob* buffer_blob) {

  C1ShenandoahPreBarrierCodeGenClosure pre_code_gen_cl;

  _pre_barrier_c1_runtime_code_blob = Runtime1::generate_blob(buffer_blob, -1,

                                                              "shenandoah_pre_barrier_slow",

                                                              false, &pre_code_gen_cl);

}