8230808: Remove Access::equals()

Reviewed-by: tschatzl, shade

src/hotspot/share/gc/shared/barrierSet.hpp

@@ -314,10 +314,6 @@ public:
     static oop resolve(oop obj) {
       return Raw::resolve(obj);
     }
-
-    static bool equals(oop o1, oop o2) {
-      return Raw::equals(o1, o2);
-    }
   };
 };
 

src/hotspot/share/oops/access.cpp

@@ -1,36 +0,0 @@
-/*
- * 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 "oops/access.inline.hpp"
-#include "oops/accessDecorators.hpp"
-
-// This macro allows instantiating selected accesses to be usable from the
-// access.hpp file, to break dependencies to the access.inline.hpp file.
-#define INSTANTIATE_HPP_ACCESS(decorators, T, barrier_type)  \
-  template struct RuntimeDispatch<DecoratorFixup<decorators>::value, T, barrier_type>
-
-namespace AccessInternal {
-  INSTANTIATE_HPP_ACCESS(DECORATORS_NONE, oop, BARRIER_EQUALS);
-}

src/hotspot/share/oops/access.hpp

@@ -58,7 +58,6 @@
 // * arraycopy: Copy data from one heap array to another heap array. The ArrayAccess class has convenience functions for this.
 // * clone: Clone the contents of an object to a newly allocated object.
 // * resolve: Resolve a stable to-space invariant oop that is guaranteed not to relocate its payload until a subsequent thread transition.
-// * equals: Object equality, e.g. when different copies of the same objects are in use (from-space vs. to-space)
 //
 // == IMPLEMENTATION ==
 // Each access goes through the following steps in a template pipeline.
@@ -275,11 +274,6 @@ public:
     verify_decorators<DECORATORS_NONE>();
     return AccessInternal::resolve<decorators>(obj);
   }
-
-  static bool equals(oop o1, oop o2) {
-    verify_decorators<AS_RAW>();
-    return AccessInternal::equals<decorators>(o1, o2);
-  }
 };
 
 // Helper for performing raw accesses (knows only of memory ordering

src/hotspot/share/oops/access.inline.hpp

@@ -206,13 +206,6 @@ namespace AccessInternal {
     }
   };
 
-  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.
@@ -367,13 +360,6 @@ namespace AccessInternal {
     _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

src/hotspot/share/oops/accessBackend.hpp

@@ -64,8 +64,7 @@ namespace AccessInternal {
     BARRIER_ATOMIC_XCHG_AT,
     BARRIER_ARRAYCOPY,
     BARRIER_CLONE,
-    BARRIER_RESOLVE,
-    BARRIER_EQUALS
+    BARRIER_RESOLVE
   };
 
   template <DecoratorSet decorators, typename T>
@@ -116,7 +115,6 @@ namespace AccessInternal {
                                      size_t length);
     typedef void (*clone_func_t)(oop src, oop dst, size_t size);
     typedef oop (*resolve_func_t)(oop obj);
-    typedef bool (*equals_func_t)(oop o1, oop o2);
   };
 
   template <DecoratorSet decorators>
@@ -144,7 +142,6 @@ namespace AccessInternal {
   ACCESS_GENERATE_ACCESS_FUNCTION(BARRIER_ARRAYCOPY, arraycopy_func_t);
   ACCESS_GENERATE_ACCESS_FUNCTION(BARRIER_CLONE, clone_func_t);
   ACCESS_GENERATE_ACCESS_FUNCTION(BARRIER_RESOLVE, resolve_func_t);
-  ACCESS_GENERATE_ACCESS_FUNCTION(BARRIER_EQUALS, equals_func_t);
 #undef ACCESS_GENERATE_ACCESS_FUNCTION
 
   template <DecoratorSet decorators, typename T, BarrierType barrier_type>
@@ -410,8 +407,6 @@ public:
   static void clone(oop src, oop dst, size_t size);
 
   static oop resolve(oop obj) { return obj; }
-
-  static bool equals(oop o1, oop o2) { return (void*)o1 == (void*)o2; }
 };
 
 // Below is the implementation of the first 4 steps of the template pipeline:
@@ -605,18 +600,6 @@ namespace AccessInternal {
     }
   };
 
-  template <DecoratorSet decorators, typename T>
-  struct RuntimeDispatch<decorators, T, BARRIER_EQUALS>: AllStatic {
-    typedef typename AccessFunction<decorators, T, BARRIER_EQUALS>::type func_t;
-    static func_t _equals_func;
-
-    static bool equals_init(oop o1, oop o2);
-
-    static inline bool equals(oop o1, oop o2) {
-      return _equals_func(o1, o2);
-    }
-  };
-
   // Initialize the function pointers to point to the resolving function.
   template <DecoratorSet decorators, typename T>
   typename AccessFunction<decorators, T, BARRIER_STORE>::type
@@ -662,10 +645,6 @@ namespace AccessInternal {
   typename AccessFunction<decorators, T, BARRIER_RESOLVE>::type
   RuntimeDispatch<decorators, T, BARRIER_RESOLVE>::_resolve_func = &resolve_init;
 
-  template <DecoratorSet decorators, typename T>
-  typename AccessFunction<decorators, T, BARRIER_EQUALS>::type
-  RuntimeDispatch<decorators, T, BARRIER_EQUALS>::_equals_func = &equals_init;
-
   // Step 3: Pre-runtime dispatching.
   // The PreRuntimeDispatch class is responsible for filtering the barrier strength
   // decorators. That is, for AS_RAW, it hardwires the accesses without a runtime
@@ -996,21 +975,6 @@ namespace AccessInternal {
     resolve(oop obj) {
       return RuntimeDispatch<decorators, oop, BARRIER_RESOLVE>::resolve(obj);
     }
-
-    template <DecoratorSet decorators>
-    inline static typename EnableIf<
-      HasDecorator<decorators, AS_RAW>::value || HasDecorator<decorators, INTERNAL_BT_TO_SPACE_INVARIANT>::value, bool>::type
-    equals(oop o1, oop o2) {
-      typedef RawAccessBarrier<decorators & RAW_DECORATOR_MASK> Raw;
-      return Raw::equals(o1, o2);
-    }
-
-    template <DecoratorSet decorators>
-    inline static typename EnableIf<
-      !HasDecorator<decorators, AS_RAW>::value && !HasDecorator<decorators, INTERNAL_BT_TO_SPACE_INVARIANT>::value, bool>::type
-    equals(oop o1, oop o2) {
-      return RuntimeDispatch<decorators, oop, BARRIER_EQUALS>::equals(o1, o2);
-    }
   };
 
   // Step 2: Reduce types.
@@ -1309,12 +1273,6 @@ namespace AccessInternal {
     return PreRuntimeDispatch::resolve<expanded_decorators>(obj);
   }
 
-  template <DecoratorSet decorators>
-  inline bool equals(oop o1, oop o2) {
-    const DecoratorSet expanded_decorators = DecoratorFixup<decorators>::value;
-    return PreRuntimeDispatch::equals<expanded_decorators>(o1, o2);
-  }
-
   // Infer the type that should be returned from an Access::oop_load.
   template <typename P, DecoratorSet decorators>
   class OopLoadProxy: public StackObj {

src/hotspot/share/oops/oop.hpp

@@ -150,9 +150,9 @@ class oopDesc {
     }
   }
 
-  inline static bool equals(oop o1, oop o2) { return Access<>::equals(o1, o2); }
+  inline static bool equals(oop o1, oop o2) { return equals_raw(o1, o2); }
 
-  inline static bool equals_raw(oop o1, oop o2) { return RawAccess<>::equals(o1, o2); }
+  inline static bool equals_raw(oop o1, oop o2) { return o1 == o2; }
 
   // Access to fields in a instanceOop through these methods.
   template <DecoratorSet decorator>