/*

 * Copyright (c) 2018, 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 "c1/c1_Defs.hpp"

#include "c1/c1_LIRGenerator.hpp"

#include "gc/shared/c1/barrierSetC1.hpp"

#include "utilities/macros.hpp"

#ifndef PATCHED_ADDR

#define PATCHED_ADDR  (max_jint)

#endif

#ifdef ASSERT

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

#else

#define __ gen->lir()->

#endif

LIR_Opr BarrierSetC1::resolve_address(LIRAccess& access, bool resolve_in_register) {

  DecoratorSet decorators = access.decorators();

  bool is_array = (decorators & IS_ARRAY) != 0;

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

  LIRItem& base = access.base().item();

  LIR_Opr offset = access.offset().opr();

  LIRGenerator *gen = access.gen();

  LIR_Opr addr_opr;

  if (is_array) {

    addr_opr = LIR_OprFact::address(gen->emit_array_address(base.result(), offset, access.type()));

  } else if (needs_patching) {

    // we need to patch the offset in the instruction so don't allow

    // generate_address to try to be smart about emitting the -1.

    // Otherwise the patching code won't know how to find the

    // instruction to patch.

    addr_opr = LIR_OprFact::address(new LIR_Address(base.result(), PATCHED_ADDR, access.type()));

  } else {

    addr_opr = LIR_OprFact::address(gen->generate_address(base.result(), offset, 0, 0, access.type()));

  }

  if (resolve_in_register) {

    LIR_Opr resolved_addr = gen->new_pointer_register();

    __ leal(addr_opr, resolved_addr);

    resolved_addr = LIR_OprFact::address(new LIR_Address(resolved_addr, access.type()));

    return resolved_addr;

  } else {

    return addr_opr;

  }

}

void BarrierSetC1::store_at(LIRAccess& access, LIR_Opr value) {

  DecoratorSet decorators = access.decorators();

  bool in_heap = (decorators & IN_HEAP) != 0;

  assert(in_heap, "not supported yet");

  LIR_Opr resolved = resolve_address(access, false);

  access.set_resolved_addr(resolved);

  store_at_resolved(access, value);

}

void BarrierSetC1::load_at(LIRAccess& access, LIR_Opr result) {

  DecoratorSet decorators = access.decorators();

  bool in_heap = (decorators & IN_HEAP) != 0;

  assert(in_heap, "not supported yet");

  LIR_Opr resolved = resolve_address(access, false);

  access.set_resolved_addr(resolved);

  load_at_resolved(access, result);

}

void BarrierSetC1::load(LIRAccess& access, LIR_Opr result) {

  DecoratorSet decorators = access.decorators();

  bool in_heap = (decorators & IN_HEAP) != 0;

  assert(!in_heap, "consider using load_at");

  load_at_resolved(access, result);

}

LIR_Opr BarrierSetC1::atomic_cmpxchg_at(LIRAccess& access, LIRItem& cmp_value, LIRItem& new_value) {

  DecoratorSet decorators = access.decorators();

  bool in_heap = (decorators & IN_HEAP) != 0;

  assert(in_heap, "not supported yet");

  access.load_address();

  LIR_Opr resolved = resolve_address(access, true);

  access.set_resolved_addr(resolved);

  return atomic_cmpxchg_at_resolved(access, cmp_value, new_value);

}

LIR_Opr BarrierSetC1::atomic_xchg_at(LIRAccess& access, LIRItem& value) {

  DecoratorSet decorators = access.decorators();

  bool in_heap = (decorators & IN_HEAP) != 0;

  assert(in_heap, "not supported yet");

  access.load_address();

  LIR_Opr resolved = resolve_address(access, true);

  access.set_resolved_addr(resolved);

  return atomic_xchg_at_resolved(access, value);

}

LIR_Opr BarrierSetC1::atomic_add_at(LIRAccess& access, LIRItem& value) {

  DecoratorSet decorators = access.decorators();

  bool in_heap = (decorators & IN_HEAP) != 0;

  assert(in_heap, "not supported yet");

  access.load_address();

  LIR_Opr resolved = resolve_address(access, true);

  access.set_resolved_addr(resolved);

  return atomic_add_at_resolved(access, value);

}

void BarrierSetC1::store_at_resolved(LIRAccess& access, LIR_Opr value) {

  DecoratorSet decorators = access.decorators();

  bool is_volatile = (((decorators & MO_SEQ_CST) != 0) || AlwaysAtomicAccesses) && os::is_MP();

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

  bool mask_boolean = (decorators & C1_MASK_BOOLEAN) != 0;

  LIRGenerator* gen = access.gen();

  if (mask_boolean) {

    value = gen->mask_boolean(access.base().opr(), value, access.access_emit_info());

  }

  if (is_volatile && os::is_MP()) {

    __ membar_release();

  }

  LIR_PatchCode patch_code = needs_patching ? lir_patch_normal : lir_patch_none;

  if (is_volatile && !needs_patching) {

    gen->volatile_field_store(value, access.resolved_addr()->as_address_ptr(), access.access_emit_info());

  } else {

    __ store(value, access.resolved_addr()->as_address_ptr(), access.access_emit_info(), patch_code);

  }

  if (is_volatile && !support_IRIW_for_not_multiple_copy_atomic_cpu) {

    __ membar();

  }

}

void BarrierSetC1::load_at_resolved(LIRAccess& access, LIR_Opr result) {

  LIRGenerator *gen = access.gen();

  DecoratorSet decorators = access.decorators();

  bool is_volatile = (((decorators & MO_SEQ_CST) != 0) || AlwaysAtomicAccesses) && os::is_MP();

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

  bool mask_boolean = (decorators & C1_MASK_BOOLEAN) != 0;

  bool in_native = (decorators & IN_NATIVE) != 0;

  if (support_IRIW_for_not_multiple_copy_atomic_cpu && is_volatile) {

    __ membar();

  }

  LIR_PatchCode patch_code = needs_patching ? lir_patch_normal : lir_patch_none;

  if (in_native) {

    __ move_wide(access.resolved_addr()->as_address_ptr(), result);

  } else if (is_volatile && !needs_patching) {

    gen->volatile_field_load(access.resolved_addr()->as_address_ptr(), result, access.access_emit_info());

  } else {

    __ load(access.resolved_addr()->as_address_ptr(), result, access.access_emit_info(), patch_code);

  }

  if (is_volatile && os::is_MP()) {

    __ membar_acquire();

  }

  /* Normalize boolean value returned by unsafe operation, i.e., value  != 0 ? value = true : value false. */

  if (mask_boolean) {

    LabelObj* equalZeroLabel = new LabelObj();

    __ cmp(lir_cond_equal, result, 0);

    __ branch(lir_cond_equal, T_BOOLEAN, equalZeroLabel->label());

    __ move(LIR_OprFact::intConst(1), result);

    __ branch_destination(equalZeroLabel->label());

  }

}

LIR_Opr BarrierSetC1::atomic_cmpxchg_at_resolved(LIRAccess& access, LIRItem& cmp_value, LIRItem& new_value) {

  LIRGenerator *gen = access.gen();

  return gen->atomic_cmpxchg(access.type(), access.resolved_addr(), cmp_value, new_value);

}

LIR_Opr BarrierSetC1::atomic_xchg_at_resolved(LIRAccess& access, LIRItem& value) {

  LIRGenerator *gen = access.gen();

  return gen->atomic_xchg(access.type(), access.resolved_addr(), value);

}

LIR_Opr BarrierSetC1::atomic_add_at_resolved(LIRAccess& access, LIRItem& value) {

  LIRGenerator *gen = access.gen();

  return gen->atomic_add(access.type(), access.resolved_addr(), value);

}

void BarrierSetC1::generate_referent_check(LIRAccess& access, LabelObj* cont) {

  // We might be reading the value of the referent field of a

  // Reference object in order to attach it back to the live

  // object graph. If G1 is enabled then we need to record

  // the value that is being returned in an SATB log buffer.

  //

  // We need to generate code similar to the following...

  //

  // if (offset == java_lang_ref_Reference::referent_offset) {

  //   if (src != NULL) {

  //     if (klass(src)->reference_type() != REF_NONE) {

  //       pre_barrier(..., value, ...);

  //     }

  //   }

  // }

  bool gen_pre_barrier = true;     // Assume we need to generate pre_barrier.

  bool gen_offset_check = true;    // Assume we need to generate the offset guard.

  bool gen_source_check = true;    // Assume we need to check the src object for null.

  bool gen_type_check = true;      // Assume we need to check the reference_type.

  LIRGenerator *gen = access.gen();

  LIRItem& base = access.base().item();

  LIR_Opr offset = access.offset().opr();

  if (offset->is_constant()) {

    LIR_Const* constant = offset->as_constant_ptr();

    jlong off_con = (constant->type() == T_INT ?

                     (jlong)constant->as_jint() :

                     constant->as_jlong());

    if (off_con != (jlong) java_lang_ref_Reference::referent_offset) {

      // The constant offset is something other than referent_offset.

      // We can skip generating/checking the remaining guards and

      // skip generation of the code stub.

      gen_pre_barrier = false;

    } else {

      // The constant offset is the same as referent_offset -

      // we do not need to generate a runtime offset check.

      gen_offset_check = false;

    }

  }

  // We don't need to generate stub if the source object is an array

  if (gen_pre_barrier && base.type()->is_array()) {

    gen_pre_barrier = false;

  }

  if (gen_pre_barrier) {

    // We still need to continue with the checks.

    if (base.is_constant()) {

      ciObject* src_con = base.get_jobject_constant();

      guarantee(src_con != NULL, "no source constant");

      if (src_con->is_null_object()) {

        // The constant src object is null - We can skip

        // generating the code stub.

        gen_pre_barrier = false;

      } else {

        // Non-null constant source object. We still have to generate

        // the slow stub - but we don't need to generate the runtime

        // null object check.

        gen_source_check = false;

      }

    }

  }

  if (gen_pre_barrier && !PatchALot) {

    // Can the klass of object be statically determined to be

    // a sub-class of Reference?

    ciType* type = base.value()->declared_type();

    if ((type != NULL) && type->is_loaded()) {

      if (type->is_subtype_of(gen->compilation()->env()->Reference_klass())) {

        gen_type_check = false;

      } else if (type->is_klass() &&

                 !gen->compilation()->env()->Object_klass()->is_subtype_of(type->as_klass())) {

        // Not Reference and not Object klass.

        gen_pre_barrier = false;

      }

    }

  }

  if (gen_pre_barrier) {

    // We can have generate one runtime check here. Let's start with

    // the offset check.

    if (gen_offset_check) {

      // if (offset != referent_offset) -> continue

      // If offset is an int then we can do the comparison with the

      // referent_offset constant; otherwise we need to move

      // referent_offset into a temporary register and generate

      // a reg-reg compare.

      LIR_Opr referent_off;

      if (offset->type() == T_INT) {

        referent_off = LIR_OprFact::intConst(java_lang_ref_Reference::referent_offset);

      } else {

        assert(offset->type() == T_LONG, "what else?");

        referent_off = gen->new_register(T_LONG);

        __ move(LIR_OprFact::longConst(java_lang_ref_Reference::referent_offset), referent_off);

      }

      __ cmp(lir_cond_notEqual, offset, referent_off);

      __ branch(lir_cond_notEqual, offset->type(), cont->label());

    }

    if (gen_source_check) {

      // offset is a const and equals referent offset

      // if (source == null) -> continue

      __ cmp(lir_cond_equal, base.result(), LIR_OprFact::oopConst(NULL));

      __ branch(lir_cond_equal, T_OBJECT, cont->label());

    }

    if (gen_type_check) {

      // We have determined that offset == referent_offset && src != null.

      // if (src->_klass->_reference_type == REF_NONE) -> continue

      __ move(new LIR_Address(base.result(), oopDesc::klass_offset_in_bytes(), T_ADDRESS), src_klass);

      LIR_Address* reference_type_addr = new LIR_Address(src_klass, in_bytes(InstanceKlass::reference_type_offset()), T_BYTE);

      LIR_Opr reference_type = gen->new_register(T_INT);

      __ move(reference_type_addr, reference_type);

      __ cmp(lir_cond_equal, reference_type, LIR_OprFact::intConst(REF_NONE));

      __ branch(lir_cond_equal, T_INT, cont->label());

    }

  }

}

LIR_Opr BarrierSetC1::resolve(LIRGenerator* gen, DecoratorSet decorators, LIR_Opr obj) {

  return obj;

}