src/hotspot/share/oops/accessBackend.hpp
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     1 /*
       
     2  * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
       
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
       
     4  *
       
     5  * This code is free software; you can redistribute it and/or modify it
       
     6  * under the terms of the GNU General Public License version 2 only, as
       
     7  * published by the Free Software Foundation.
       
     8  *
       
     9  * This code is distributed in the hope that it will be useful, but WITHOUT
       
    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
       
    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
       
    12  * version 2 for more details (a copy is included in the LICENSE file that
       
    13  * accompanied this code).
       
    14  *
       
    15  * You should have received a copy of the GNU General Public License version
       
    16  * 2 along with this work; if not, write to the Free Software Foundation,
       
    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
       
    18  *
       
    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
       
    20  * or visit www.oracle.com if you need additional information or have any
       
    21  * questions.
       
    22  *
       
    23  */
       
    24 
       
    25 #ifndef SHARE_VM_RUNTIME_ACCESSBACKEND_HPP
       
    26 #define SHARE_VM_RUNTIME_ACCESSBACKEND_HPP
       
    27 
       
    28 #include "metaprogramming/conditional.hpp"
       
    29 #include "metaprogramming/enableIf.hpp"
       
    30 #include "metaprogramming/integralConstant.hpp"
       
    31 #include "utilities/debug.hpp"
       
    32 #include "utilities/globalDefinitions.hpp"
       
    33 
       
    34 // This metafunction returns either oop or narrowOop depending on whether
       
    35 // an access needs to use compressed oops or not.
       
    36 template <DecoratorSet decorators>
       
    37 struct HeapOopType: AllStatic {
       
    38   static const bool needs_oop_compress = HasDecorator<decorators, INTERNAL_CONVERT_COMPRESSED_OOP>::value &&
       
    39                                          HasDecorator<decorators, INTERNAL_RT_USE_COMPRESSED_OOPS>::value;
       
    40   typedef typename Conditional<needs_oop_compress, narrowOop, oop>::type type;
       
    41 };
       
    42 
       
    43 namespace AccessInternal {
       
    44   enum BarrierType {
       
    45     BARRIER_STORE,
       
    46     BARRIER_STORE_AT,
       
    47     BARRIER_LOAD,
       
    48     BARRIER_LOAD_AT,
       
    49     BARRIER_ATOMIC_CMPXCHG,
       
    50     BARRIER_ATOMIC_CMPXCHG_AT,
       
    51     BARRIER_ATOMIC_XCHG,
       
    52     BARRIER_ATOMIC_XCHG_AT,
       
    53     BARRIER_ARRAYCOPY,
       
    54     BARRIER_CLONE
       
    55   };
       
    56 
       
    57   template <DecoratorSet decorators>
       
    58   struct MustConvertCompressedOop: public IntegralConstant<bool,
       
    59     HasDecorator<decorators, INTERNAL_VALUE_IS_OOP>::value &&
       
    60     HasDecorator<decorators, INTERNAL_CONVERT_COMPRESSED_OOP>::value &&
       
    61     HasDecorator<decorators, INTERNAL_RT_USE_COMPRESSED_OOPS>::value> {};
       
    62 
       
    63   // This metafunction returns an appropriate oop type if the value is oop-like
       
    64   // and otherwise returns the same type T.
       
    65   template <DecoratorSet decorators, typename T>
       
    66   struct EncodedType: AllStatic {
       
    67     typedef typename Conditional<
       
    68       HasDecorator<decorators, INTERNAL_VALUE_IS_OOP>::value,
       
    69       typename HeapOopType<decorators>::type, T>::type type;
       
    70   };
       
    71 
       
    72   template <DecoratorSet decorators>
       
    73   inline typename HeapOopType<decorators>::type*
       
    74   oop_field_addr(oop base, ptrdiff_t byte_offset) {
       
    75     return reinterpret_cast<typename HeapOopType<decorators>::type*>(
       
    76              reinterpret_cast<intptr_t>((void*)base) + byte_offset);
       
    77   }
       
    78 
       
    79   // This metafunction returns whether it is possible for a type T to require
       
    80   // locking to support wide atomics or not.
       
    81   template <typename T>
       
    82 #ifdef SUPPORTS_NATIVE_CX8
       
    83   struct PossiblyLockedAccess: public IntegralConstant<bool, false> {};
       
    84 #else
       
    85   struct PossiblyLockedAccess: public IntegralConstant<bool, (sizeof(T) > 4)>::value> {};
       
    86 #endif
       
    87 
       
    88   template <DecoratorSet decorators, typename T>
       
    89   struct AccessFunctionTypes {
       
    90     typedef T (*load_at_func_t)(oop base, ptrdiff_t offset);
       
    91     typedef void (*store_at_func_t)(oop base, ptrdiff_t offset, T value);
       
    92     typedef T (*atomic_cmpxchg_at_func_t)(T new_value, oop base, ptrdiff_t offset, T compare_value);
       
    93     typedef T (*atomic_xchg_at_func_t)(T new_value, oop base, ptrdiff_t offset);
       
    94 
       
    95     typedef T (*load_func_t)(void* addr);
       
    96     typedef void (*store_func_t)(void* addr, T value);
       
    97     typedef T (*atomic_cmpxchg_func_t)(T new_value, void* addr, T compare_value);
       
    98     typedef T (*atomic_xchg_func_t)(T new_value, void* addr);
       
    99 
       
   100     typedef bool (*arraycopy_func_t)(arrayOop src_obj, arrayOop dst_obj, T* src, T* dst, size_t length);
       
   101     typedef void (*clone_func_t)(oop src, oop dst, size_t size);
       
   102   };
       
   103 
       
   104   template <DecoratorSet decorators, typename T, BarrierType barrier> struct AccessFunction {};
       
   105 
       
   106 #define ACCESS_GENERATE_ACCESS_FUNCTION(bt, func)                   \
       
   107   template <DecoratorSet decorators, typename T>                    \
       
   108   struct AccessFunction<decorators, T, bt>: AllStatic{              \
       
   109     typedef typename AccessFunctionTypes<decorators, T>::func type; \
       
   110   }
       
   111   ACCESS_GENERATE_ACCESS_FUNCTION(BARRIER_STORE, store_func_t);
       
   112   ACCESS_GENERATE_ACCESS_FUNCTION(BARRIER_STORE_AT, store_at_func_t);
       
   113   ACCESS_GENERATE_ACCESS_FUNCTION(BARRIER_LOAD, load_func_t);
       
   114   ACCESS_GENERATE_ACCESS_FUNCTION(BARRIER_LOAD_AT, load_at_func_t);
       
   115   ACCESS_GENERATE_ACCESS_FUNCTION(BARRIER_ATOMIC_CMPXCHG, atomic_cmpxchg_func_t);
       
   116   ACCESS_GENERATE_ACCESS_FUNCTION(BARRIER_ATOMIC_CMPXCHG_AT, atomic_cmpxchg_at_func_t);
       
   117   ACCESS_GENERATE_ACCESS_FUNCTION(BARRIER_ATOMIC_XCHG, atomic_xchg_func_t);
       
   118   ACCESS_GENERATE_ACCESS_FUNCTION(BARRIER_ATOMIC_XCHG_AT, atomic_xchg_at_func_t);
       
   119   ACCESS_GENERATE_ACCESS_FUNCTION(BARRIER_ARRAYCOPY, arraycopy_func_t);
       
   120   ACCESS_GENERATE_ACCESS_FUNCTION(BARRIER_CLONE, clone_func_t);
       
   121 #undef ACCESS_GENERATE_ACCESS_FUNCTION
       
   122 
       
   123   template <DecoratorSet decorators, typename T, BarrierType barrier_type>
       
   124   typename AccessFunction<decorators, T, barrier_type>::type resolve_barrier();
       
   125 
       
   126   template <DecoratorSet decorators, typename T, BarrierType barrier_type>
       
   127   typename AccessFunction<decorators, T, barrier_type>::type resolve_oop_barrier();
       
   128 
       
   129   class AccessLocker VALUE_OBJ_CLASS_SPEC {
       
   130   public:
       
   131     AccessLocker();
       
   132     ~AccessLocker();
       
   133   };
       
   134   bool wide_atomic_needs_locking();
       
   135 
       
   136   void* field_addr(oop base, ptrdiff_t offset);
       
   137 
       
   138   // Forward calls to Copy:: in the cpp file to reduce dependencies and allow
       
   139   // faster build times, given how frequently included access is.
       
   140   void arraycopy_arrayof_conjoint_oops(void* src, void* dst, size_t length);
       
   141   void arraycopy_conjoint_oops(oop* src, oop* dst, size_t length);
       
   142   void arraycopy_conjoint_oops(narrowOop* src, narrowOop* dst, size_t length);
       
   143 
       
   144   void arraycopy_disjoint_words(void* src, void* dst, size_t length);
       
   145   void arraycopy_disjoint_words_atomic(void* src, void* dst, size_t length);
       
   146 
       
   147   template<typename T>
       
   148   void arraycopy_conjoint(T* src, T* dst, size_t length);
       
   149   template<typename T>
       
   150   void arraycopy_arrayof_conjoint(T* src, T* dst, size_t length);
       
   151   template<typename T>
       
   152   void arraycopy_conjoint_atomic(T* src, T* dst, size_t length);
       
   153 }
       
   154 
       
   155 // This mask specifies what decorators are relevant for raw accesses. When passing
       
   156 // accesses to the raw layer, irrelevant decorators are removed.
       
   157 const DecoratorSet RAW_DECORATOR_MASK = INTERNAL_DECORATOR_MASK | MO_DECORATOR_MASK |
       
   158                                         ARRAYCOPY_DECORATOR_MASK | OOP_DECORATOR_MASK;
       
   159 
       
   160 // The RawAccessBarrier performs raw accesses with additional knowledge of
       
   161 // memory ordering, so that OrderAccess/Atomic is called when necessary.
       
   162 // It additionally handles compressed oops, and hence is not completely "raw"
       
   163 // strictly speaking.
       
   164 template <DecoratorSet decorators>
       
   165 class RawAccessBarrier: public AllStatic {
       
   166 protected:
       
   167   static inline void* field_addr(oop base, ptrdiff_t byte_offset) {
       
   168     return AccessInternal::field_addr(base, byte_offset);
       
   169   }
       
   170 
       
   171 protected:
       
   172   // Only encode if INTERNAL_VALUE_IS_OOP
       
   173   template <DecoratorSet idecorators, typename T>
       
   174   static inline typename EnableIf<
       
   175     AccessInternal::MustConvertCompressedOop<idecorators>::value,
       
   176     typename HeapOopType<idecorators>::type>::type
       
   177   encode_internal(T value);
       
   178 
       
   179   template <DecoratorSet idecorators, typename T>
       
   180   static inline typename EnableIf<
       
   181     !AccessInternal::MustConvertCompressedOop<idecorators>::value, T>::type
       
   182   encode_internal(T value) {
       
   183     return value;
       
   184   }
       
   185 
       
   186   template <typename T>
       
   187   static inline typename AccessInternal::EncodedType<decorators, T>::type
       
   188   encode(T value) {
       
   189     return encode_internal<decorators, T>(value);
       
   190   }
       
   191 
       
   192   // Only decode if INTERNAL_VALUE_IS_OOP
       
   193   template <DecoratorSet idecorators, typename T>
       
   194   static inline typename EnableIf<
       
   195     AccessInternal::MustConvertCompressedOop<idecorators>::value, T>::type
       
   196   decode_internal(typename HeapOopType<idecorators>::type value);
       
   197 
       
   198   template <DecoratorSet idecorators, typename T>
       
   199   static inline typename EnableIf<
       
   200     !AccessInternal::MustConvertCompressedOop<idecorators>::value, T>::type
       
   201   decode_internal(T value) {
       
   202     return value;
       
   203   }
       
   204 
       
   205   template <typename T>
       
   206   static inline T decode(typename AccessInternal::EncodedType<decorators, T>::type value) {
       
   207     return decode_internal<decorators, T>(value);
       
   208   }
       
   209 
       
   210 protected:
       
   211   template <DecoratorSet ds, typename T>
       
   212   static typename EnableIf<
       
   213     HasDecorator<ds, MO_SEQ_CST>::value, T>::type
       
   214   load_internal(void* addr);
       
   215 
       
   216   template <DecoratorSet ds, typename T>
       
   217   static typename EnableIf<
       
   218     HasDecorator<ds, MO_ACQUIRE>::value, T>::type
       
   219   load_internal(void* addr);
       
   220 
       
   221   template <DecoratorSet ds, typename T>
       
   222   static typename EnableIf<
       
   223     HasDecorator<ds, MO_RELAXED>::value, T>::type
       
   224   load_internal(void* addr);
       
   225 
       
   226   template <DecoratorSet ds, typename T>
       
   227   static inline typename EnableIf<
       
   228     HasDecorator<ds, MO_VOLATILE>::value, T>::type
       
   229   load_internal(void* addr) {
       
   230     return *reinterpret_cast<const volatile T*>(addr);
       
   231   }
       
   232 
       
   233   template <DecoratorSet ds, typename T>
       
   234   static inline typename EnableIf<
       
   235     HasDecorator<ds, MO_UNORDERED>::value, T>::type
       
   236   load_internal(void* addr) {
       
   237     return *reinterpret_cast<const T*>(addr);
       
   238   }
       
   239 
       
   240   template <DecoratorSet ds, typename T>
       
   241   static typename EnableIf<
       
   242     HasDecorator<ds, MO_SEQ_CST>::value>::type
       
   243   store_internal(void* addr, T value);
       
   244 
       
   245   template <DecoratorSet ds, typename T>
       
   246   static typename EnableIf<
       
   247     HasDecorator<ds, MO_RELEASE>::value>::type
       
   248   store_internal(void* addr, T value);
       
   249 
       
   250   template <DecoratorSet ds, typename T>
       
   251   static typename EnableIf<
       
   252     HasDecorator<ds, MO_RELAXED>::value>::type
       
   253   store_internal(void* addr, T value);
       
   254 
       
   255   template <DecoratorSet ds, typename T>
       
   256   static inline typename EnableIf<
       
   257     HasDecorator<ds, MO_VOLATILE>::value>::type
       
   258   store_internal(void* addr, T value) {
       
   259     (void)const_cast<T&>(*reinterpret_cast<volatile T*>(addr) = value);
       
   260   }
       
   261 
       
   262   template <DecoratorSet ds, typename T>
       
   263   static inline typename EnableIf<
       
   264     HasDecorator<ds, MO_UNORDERED>::value>::type
       
   265   store_internal(void* addr, T value) {
       
   266     *reinterpret_cast<T*>(addr) = value;
       
   267   }
       
   268 
       
   269   template <DecoratorSet ds, typename T>
       
   270   static typename EnableIf<
       
   271     HasDecorator<ds, MO_SEQ_CST>::value, T>::type
       
   272   atomic_cmpxchg_internal(T new_value, void* addr, T compare_value);
       
   273 
       
   274   template <DecoratorSet ds, typename T>
       
   275   static typename EnableIf<
       
   276     HasDecorator<ds, MO_RELAXED>::value, T>::type
       
   277   atomic_cmpxchg_internal(T new_value, void* addr, T compare_value);
       
   278 
       
   279   template <DecoratorSet ds, typename T>
       
   280   static typename EnableIf<
       
   281     HasDecorator<ds, MO_SEQ_CST>::value, T>::type
       
   282   atomic_xchg_internal(T new_value, void* addr);
       
   283 
       
   284   // The following *_locked mechanisms serve the purpose of handling atomic operations
       
   285   // that are larger than a machine can handle, and then possibly opt for using
       
   286   // a slower path using a mutex to perform the operation.
       
   287 
       
   288   template <DecoratorSet ds, typename T>
       
   289   static inline typename EnableIf<
       
   290     !AccessInternal::PossiblyLockedAccess<T>::value, T>::type
       
   291   atomic_cmpxchg_maybe_locked(T new_value, void* addr, T compare_value) {
       
   292     return atomic_cmpxchg_internal<ds>(new_value, addr, compare_value);
       
   293   }
       
   294 
       
   295   template <DecoratorSet ds, typename T>
       
   296   static typename EnableIf<
       
   297     AccessInternal::PossiblyLockedAccess<T>::value, T>::type
       
   298   atomic_cmpxchg_maybe_locked(T new_value, void* addr, T compare_value);
       
   299 
       
   300   template <DecoratorSet ds, typename T>
       
   301   static inline typename EnableIf<
       
   302     !AccessInternal::PossiblyLockedAccess<T>::value, T>::type
       
   303   atomic_xchg_maybe_locked(T new_value, void* addr) {
       
   304     return atomic_xchg_internal<ds>(new_value, addr);
       
   305   }
       
   306 
       
   307   template <DecoratorSet ds, typename T>
       
   308   static typename EnableIf<
       
   309     AccessInternal::PossiblyLockedAccess<T>::value, T>::type
       
   310   atomic_xchg_maybe_locked(T new_value, void* addr);
       
   311 
       
   312 public:
       
   313   template <typename T>
       
   314   static inline void store(void* addr, T value) {
       
   315     store_internal<decorators>(addr, value);
       
   316   }
       
   317 
       
   318   template <typename T>
       
   319   static inline T load(void* addr) {
       
   320     return load_internal<decorators, T>(addr);
       
   321   }
       
   322 
       
   323   template <typename T>
       
   324   static inline T atomic_cmpxchg(T new_value, void* addr, T compare_value) {
       
   325     return atomic_cmpxchg_maybe_locked<decorators>(new_value, addr, compare_value);
       
   326   }
       
   327 
       
   328   template <typename T>
       
   329   static inline T atomic_xchg(T new_value, void* addr) {
       
   330     return atomic_xchg_maybe_locked<decorators>(new_value, addr);
       
   331   }
       
   332 
       
   333   template <typename T>
       
   334   static bool arraycopy(T* src, T* dst, size_t length);
       
   335 
       
   336   template <typename T>
       
   337   static void oop_store(void* addr, T value);
       
   338   template <typename T>
       
   339   static void oop_store_at(oop base, ptrdiff_t offset, T value);
       
   340 
       
   341   template <typename T>
       
   342   static T oop_load(void* addr);
       
   343   template <typename T>
       
   344   static T oop_load_at(oop base, ptrdiff_t offset);
       
   345 
       
   346   template <typename T>
       
   347   static T oop_atomic_cmpxchg(T new_value, void* addr, T compare_value);
       
   348   template <typename T>
       
   349   static T oop_atomic_cmpxchg_at(T new_value, oop base, ptrdiff_t offset, T compare_value);
       
   350 
       
   351   template <typename T>
       
   352   static T oop_atomic_xchg(T new_value, void* addr);
       
   353   template <typename T>
       
   354   static T oop_atomic_xchg_at(T new_value, oop base, ptrdiff_t offset);
       
   355 
       
   356   template <typename T>
       
   357   static void store_at(oop base, ptrdiff_t offset, T value) {
       
   358     store(field_addr(base, offset), value);
       
   359   }
       
   360 
       
   361   template <typename T>
       
   362   static T load_at(oop base, ptrdiff_t offset) {
       
   363     return load<T>(field_addr(base, offset));
       
   364   }
       
   365 
       
   366   template <typename T>
       
   367   static T atomic_cmpxchg_at(T new_value, oop base, ptrdiff_t offset, T compare_value) {
       
   368     return atomic_cmpxchg(new_value, field_addr(base, offset), compare_value);
       
   369   }
       
   370 
       
   371   template <typename T>
       
   372   static T atomic_xchg_at(T new_value, oop base, ptrdiff_t offset) {
       
   373     return atomic_xchg(new_value, field_addr(base, offset));
       
   374   }
       
   375 
       
   376   template <typename T>
       
   377   static bool oop_arraycopy(arrayOop src_obj, arrayOop dst_obj, T* src, T* dst, size_t length);
       
   378   static bool oop_arraycopy(arrayOop src_obj, arrayOop dst_obj, HeapWord* src, HeapWord* dst, size_t length);
       
   379 
       
   380   static void clone(oop src, oop dst, size_t size);
       
   381 };
       
   382 
       
   383 #endif // SHARE_VM_RUNTIME_ACCESSBACKEND_HPP