/*

 * Copyright (c) 2017, 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

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 */

#ifndef SHARE_OOPS_ACCESS_INLINE_HPP

#define SHARE_OOPS_ACCESS_INLINE_HPP

#include "gc/shared/barrierSetConfig.inline.hpp"

#include "oops/access.hpp"

#include "oops/accessBackend.inline.hpp"

// This file outlines the last 2 steps of the template pipeline of accesses going through

// the Access API.

// * Step 5.a: Barrier resolution. This step is invoked the first time a runtime-dispatch

//             happens for an access. The appropriate BarrierSet::AccessBarrier accessor

//             is resolved, then the function pointer is updated to that accessor for

//             future invocations.

// * Step 5.b: Post-runtime dispatch. This step now casts previously unknown types such

//             as the address type of an oop on the heap (is it oop* or narrowOop*) to

//             the appropriate type. It also splits sufficiently orthogonal accesses into

//             different functions, such as whether the access involves oops or primitives

//             and whether the access is performed on the heap or outside. Then the

//             appropriate BarrierSet::AccessBarrier is called to perform the access.

namespace AccessInternal {

  // Step 5.b: Post-runtime dispatch.

  // This class is the last step before calling the BarrierSet::AccessBarrier.

  // Here we make sure to figure out types that were not known prior to the

  // runtime dispatch, such as whether an oop on the heap is oop or narrowOop.

  // We also split orthogonal barriers such as handling primitives vs oops

  // and on-heap vs off-heap into different calls to the barrier set.

  template <class GCBarrierType, BarrierType type, DecoratorSet decorators>

  struct PostRuntimeDispatch: public AllStatic { };

  template <class GCBarrierType, DecoratorSet decorators>

  struct PostRuntimeDispatch<GCBarrierType, BARRIER_STORE, decorators>: public AllStatic {

    template <typename T>

    static void access_barrier(void* addr, T value) {

      GCBarrierType::store_in_heap(reinterpret_cast<T*>(addr), value);

    }

    static void oop_access_barrier(void* addr, oop value) {

      typedef typename HeapOopType<decorators>::type OopType;

      if (HasDecorator<decorators, IN_HEAP>::value) {

        GCBarrierType::oop_store_in_heap(reinterpret_cast<OopType*>(addr), value);

      } else {

        GCBarrierType::oop_store_not_in_heap(reinterpret_cast<OopType*>(addr), value);

      }

    }

  };

  template <class GCBarrierType, DecoratorSet decorators>

  struct PostRuntimeDispatch<GCBarrierType, BARRIER_LOAD, decorators>: public AllStatic {

    template <typename T>

    static T access_barrier(void* addr) {

      return GCBarrierType::load_in_heap(reinterpret_cast<T*>(addr));

    }

    static oop oop_access_barrier(void* addr) {

      typedef typename HeapOopType<decorators>::type OopType;

      if (HasDecorator<decorators, IN_HEAP>::value) {

        return GCBarrierType::oop_load_in_heap(reinterpret_cast<OopType*>(addr));

      } else {

        return GCBarrierType::oop_load_not_in_heap(reinterpret_cast<OopType*>(addr));

      }

    }

  };

  template <class GCBarrierType, DecoratorSet decorators>

  struct PostRuntimeDispatch<GCBarrierType, BARRIER_ATOMIC_XCHG, decorators>: public AllStatic {

    template <typename T>

    static T access_barrier(T new_value, void* addr) {

      return GCBarrierType::atomic_xchg_in_heap(new_value, reinterpret_cast<T*>(addr));

    }

    static oop oop_access_barrier(oop new_value, void* addr) {

      typedef typename HeapOopType<decorators>::type OopType;

      if (HasDecorator<decorators, IN_HEAP>::value) {

        return GCBarrierType::oop_atomic_xchg_in_heap(new_value, reinterpret_cast<OopType*>(addr));

      } else {

        return GCBarrierType::oop_atomic_xchg_not_in_heap(new_value, reinterpret_cast<OopType*>(addr));

      }

    }

  };

  template <class GCBarrierType, DecoratorSet decorators>

  struct PostRuntimeDispatch<GCBarrierType, BARRIER_ATOMIC_CMPXCHG, decorators>: public AllStatic {

    template <typename T>

    static T access_barrier(T new_value, void* addr, T compare_value) {

      return GCBarrierType::atomic_cmpxchg_in_heap(new_value, reinterpret_cast<T*>(addr), compare_value);

    }

    static oop oop_access_barrier(oop new_value, void* addr, oop compare_value) {

      typedef typename HeapOopType<decorators>::type OopType;

      if (HasDecorator<decorators, IN_HEAP>::value) {

        return GCBarrierType::oop_atomic_cmpxchg_in_heap(new_value, reinterpret_cast<OopType*>(addr), compare_value);

      } else {

        return GCBarrierType::oop_atomic_cmpxchg_not_in_heap(new_value, reinterpret_cast<OopType*>(addr), compare_value);

      }

    }

  };

  template <class GCBarrierType, DecoratorSet decorators>

  struct PostRuntimeDispatch<GCBarrierType, BARRIER_ARRAYCOPY, decorators>: public AllStatic {

    template <typename T>

      return true;

    }

    template <typename T>

      typedef typename HeapOopType<decorators>::type OopType;

    }

  };

  template <class GCBarrierType, DecoratorSet decorators>

  struct PostRuntimeDispatch<GCBarrierType, BARRIER_STORE_AT, decorators>: public AllStatic {

    template <typename T>

    static void access_barrier(oop base, ptrdiff_t offset, T value) {

      GCBarrierType::store_in_heap_at(base, offset, value);

    }

    static void oop_access_barrier(oop base, ptrdiff_t offset, oop value) {

      GCBarrierType::oop_store_in_heap_at(base, offset, value);

    }

  };

  template <class GCBarrierType, DecoratorSet decorators>

  struct PostRuntimeDispatch<GCBarrierType, BARRIER_LOAD_AT, decorators>: public AllStatic {

    template <typename T>

    static T access_barrier(oop base, ptrdiff_t offset) {

      return GCBarrierType::template load_in_heap_at<T>(base, offset);

    }

    static oop oop_access_barrier(oop base, ptrdiff_t offset) {

      return GCBarrierType::oop_load_in_heap_at(base, offset);

    }

  };

  template <class GCBarrierType, DecoratorSet decorators>

  struct PostRuntimeDispatch<GCBarrierType, BARRIER_ATOMIC_XCHG_AT, decorators>: public AllStatic {

    template <typename T>

    static T access_barrier(T new_value, oop base, ptrdiff_t offset) {

      return GCBarrierType::atomic_xchg_in_heap_at(new_value, base, offset);

    }

    static oop oop_access_barrier(oop new_value, oop base, ptrdiff_t offset) {

      return GCBarrierType::oop_atomic_xchg_in_heap_at(new_value, base, offset);

    }

  };

  template <class GCBarrierType, DecoratorSet decorators>

  struct PostRuntimeDispatch<GCBarrierType, BARRIER_ATOMIC_CMPXCHG_AT, decorators>: public AllStatic {

    template <typename T>

    static T access_barrier(T new_value, oop base, ptrdiff_t offset, T compare_value) {

      return GCBarrierType::atomic_cmpxchg_in_heap_at(new_value, base, offset, compare_value);

    }

    static oop oop_access_barrier(oop new_value, oop base, ptrdiff_t offset, oop compare_value) {

      return GCBarrierType::oop_atomic_cmpxchg_in_heap_at(new_value, base, offset, compare_value);

    }

  };

  template <class GCBarrierType, DecoratorSet decorators>

  struct PostRuntimeDispatch<GCBarrierType, BARRIER_CLONE, decorators>: public AllStatic {

    static void access_barrier(oop src, oop dst, size_t size) {

      GCBarrierType::clone_in_heap(src, dst, size);

    }

  };

  template <class GCBarrierType, DecoratorSet decorators>

  struct PostRuntimeDispatch<GCBarrierType, BARRIER_RESOLVE, decorators>: public AllStatic {

    static oop access_barrier(oop obj) {

      return GCBarrierType::resolve(obj);

    }

  };

  template <class GCBarrierType, DecoratorSet decorators>

  struct PostRuntimeDispatch<GCBarrierType, BARRIER_EQUALS, decorators>: public AllStatic {

    static bool access_barrier(oop o1, oop o2) {

      return GCBarrierType::equals(o1, o2);

    }

  };

  // Resolving accessors with barriers from the barrier set happens in two steps.

  // 1. Expand paths with runtime-decorators, e.g. is UseCompressedOops on or off.

  // 2. Expand paths for each BarrierSet available in the system.

  template <DecoratorSet decorators, typename FunctionPointerT, BarrierType barrier_type>

  struct BarrierResolver: public AllStatic {

    template <DecoratorSet ds>

    static typename EnableIf<

      HasDecorator<ds, INTERNAL_VALUE_IS_OOP>::value,

      FunctionPointerT>::type

    resolve_barrier_gc() {

      BarrierSet* bs = BarrierSet::barrier_set();

      assert(bs != NULL, "GC barriers invoked before BarrierSet is set");

      switch (bs->kind()) {

#define BARRIER_SET_RESOLVE_BARRIER_CLOSURE(bs_name)                    \

        case BarrierSet::bs_name: {                                     \

          return PostRuntimeDispatch<typename BarrierSet::GetType<BarrierSet::bs_name>::type:: \

            AccessBarrier<ds>, barrier_type, ds>::oop_access_barrier; \

        }                                                               \

        break;

        FOR_EACH_CONCRETE_BARRIER_SET_DO(BARRIER_SET_RESOLVE_BARRIER_CLOSURE)

#undef BARRIER_SET_RESOLVE_BARRIER_CLOSURE

      default:

        fatal("BarrierSet AccessBarrier resolving not implemented");

        return NULL;

      };

    }

    template <DecoratorSet ds>

    static typename EnableIf<

      !HasDecorator<ds, INTERNAL_VALUE_IS_OOP>::value,

      FunctionPointerT>::type

    resolve_barrier_gc() {

      BarrierSet* bs = BarrierSet::barrier_set();

      assert(bs != NULL, "GC barriers invoked before BarrierSet is set");

      switch (bs->kind()) {

#define BARRIER_SET_RESOLVE_BARRIER_CLOSURE(bs_name)                    \

        case BarrierSet::bs_name: {                                       \

          return PostRuntimeDispatch<typename BarrierSet::GetType<BarrierSet::bs_name>::type:: \

            AccessBarrier<ds>, barrier_type, ds>::access_barrier; \

        }                                                                 \

        break;

        FOR_EACH_CONCRETE_BARRIER_SET_DO(BARRIER_SET_RESOLVE_BARRIER_CLOSURE)

#undef BARRIER_SET_RESOLVE_BARRIER_CLOSURE

      default:

        fatal("BarrierSet AccessBarrier resolving not implemented");

        return NULL;

      };

    }

    static FunctionPointerT resolve_barrier_rt() {

      if (UseCompressedOops) {

        const DecoratorSet expanded_decorators = decorators | INTERNAL_RT_USE_COMPRESSED_OOPS;

        return resolve_barrier_gc<expanded_decorators>();

      } else {

        return resolve_barrier_gc<decorators>();

      }

    }

    static FunctionPointerT resolve_barrier() {

      return resolve_barrier_rt();

    }

  };

  // Step 5.a: Barrier resolution

  // The RuntimeDispatch class is responsible for performing a runtime dispatch of the

  // accessor. This is required when the access either depends on whether compressed oops

  // is being used, or it depends on which GC implementation was chosen (e.g. requires GC

  // barriers). The way it works is that a function pointer initially pointing to an

  // accessor resolution function gets called for each access. Upon first invocation,

  // it resolves which accessor to be used in future invocations and patches the

  // function pointer to this new accessor.

  template <DecoratorSet decorators, typename T>

  void RuntimeDispatch<decorators, T, BARRIER_STORE>::store_init(void* addr, T value) {

    func_t function = BarrierResolver<decorators, func_t, BARRIER_STORE>::resolve_barrier();

    _store_func = function;

    function(addr, value);

  }

  template <DecoratorSet decorators, typename T>

  void RuntimeDispatch<decorators, T, BARRIER_STORE_AT>::store_at_init(oop base, ptrdiff_t offset, T value) {

    func_t function = BarrierResolver<decorators, func_t, BARRIER_STORE_AT>::resolve_barrier();

    _store_at_func = function;

    function(base, offset, value);

  }

  template <DecoratorSet decorators, typename T>

  T RuntimeDispatch<decorators, T, BARRIER_LOAD>::load_init(void* addr) {

    func_t function = BarrierResolver<decorators, func_t, BARRIER_LOAD>::resolve_barrier();

    _load_func = function;

    return function(addr);

  }

  template <DecoratorSet decorators, typename T>

  T RuntimeDispatch<decorators, T, BARRIER_LOAD_AT>::load_at_init(oop base, ptrdiff_t offset) {

    func_t function = BarrierResolver<decorators, func_t, BARRIER_LOAD_AT>::resolve_barrier();

    _load_at_func = function;

    return function(base, offset);

  }

  template <DecoratorSet decorators, typename T>

  T RuntimeDispatch<decorators, T, BARRIER_ATOMIC_CMPXCHG>::atomic_cmpxchg_init(T new_value, void* addr, T compare_value) {

    func_t function = BarrierResolver<decorators, func_t, BARRIER_ATOMIC_CMPXCHG>::resolve_barrier();

    _atomic_cmpxchg_func = function;

    return function(new_value, addr, compare_value);

  }

  template <DecoratorSet decorators, typename T>

  T RuntimeDispatch<decorators, T, BARRIER_ATOMIC_CMPXCHG_AT>::atomic_cmpxchg_at_init(T new_value, oop base, ptrdiff_t offset, T compare_value) {

    func_t function = BarrierResolver<decorators, func_t, BARRIER_ATOMIC_CMPXCHG_AT>::resolve_barrier();

    _atomic_cmpxchg_at_func = function;

    return function(new_value, base, offset, compare_value);

  }

  template <DecoratorSet decorators, typename T>

  T RuntimeDispatch<decorators, T, BARRIER_ATOMIC_XCHG>::atomic_xchg_init(T new_value, void* addr) {

    func_t function = BarrierResolver<decorators, func_t, BARRIER_ATOMIC_XCHG>::resolve_barrier();

    _atomic_xchg_func = function;

    return function(new_value, addr);

  }

  template <DecoratorSet decorators, typename T>

  T RuntimeDispatch<decorators, T, BARRIER_ATOMIC_XCHG_AT>::atomic_xchg_at_init(T new_value, oop base, ptrdiff_t offset) {

    func_t function = BarrierResolver<decorators, func_t, BARRIER_ATOMIC_XCHG_AT>::resolve_barrier();

    _atomic_xchg_at_func = function;

    return function(new_value, base, offset);

  }

  template <DecoratorSet decorators, typename T>

    func_t function = BarrierResolver<decorators, func_t, BARRIER_ARRAYCOPY>::resolve_barrier();

    _arraycopy_func = function;

  }

  template <DecoratorSet decorators, typename T>

  void RuntimeDispatch<decorators, T, BARRIER_CLONE>::clone_init(oop src, oop dst, size_t size) {

    func_t function = BarrierResolver<decorators, func_t, BARRIER_CLONE>::resolve_barrier();

    _clone_func = function;

    function(src, dst, size);

  }

  template <DecoratorSet decorators, typename T>

  oop RuntimeDispatch<decorators, T, BARRIER_RESOLVE>::resolve_init(oop obj) {

    func_t function = BarrierResolver<decorators, func_t, BARRIER_RESOLVE>::resolve_barrier();

    _resolve_func = function;

    return function(obj);

  }

  template <DecoratorSet decorators, typename T>

  bool RuntimeDispatch<decorators, T, BARRIER_EQUALS>::equals_init(oop o1, oop o2) {

    func_t function = BarrierResolver<decorators, func_t, BARRIER_EQUALS>::resolve_barrier();

    _equals_func = function;

    return function(o1, o2);

  }

}

#endif // SHARE_OOPS_ACCESS_INLINE_HPP