1 /* 2 * Copyright (c) 2000, 2018, 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_GC_SHARED_BARRIERSET_HPP 26 #define SHARE_VM_GC_SHARED_BARRIERSET_HPP 27 28 #include "gc/shared/barrierSetConfig.hpp" 29 #include "memory/memRegion.hpp" 30 #include "oops/access.hpp" 31 #include "oops/accessBackend.hpp" 32 #include "oops/oopsHierarchy.hpp" 33 #include "utilities/fakeRttiSupport.hpp" 34 35 // This class provides the interface between a barrier implementation and 36 // the rest of the system. 37 38 class BarrierSet: public CHeapObj<mtGC> { 39 friend class VMStructs; 40 41 static BarrierSet* _bs; 42 43 public: 44 enum Name { 45 #define BARRIER_SET_DECLARE_BS_ENUM(bs_name) bs_name , 46 FOR_EACH_BARRIER_SET_DO(BARRIER_SET_DECLARE_BS_ENUM) 47 #undef BARRIER_SET_DECLARE_BS_ENUM 48 UnknownBS 49 }; 50 51 static BarrierSet* barrier_set() { return _bs; } 52 53 protected: 54 // Fake RTTI support. For a derived class T to participate 55 // - T must have a corresponding Name entry. 56 // - GetName<T> must be specialized to return the corresponding Name 57 // entry. 58 // - If T is a base class, the constructor must have a FakeRtti 59 // parameter and pass it up to its base class, with the tag set 60 // augmented with the corresponding Name entry. 61 // - If T is a concrete class, the constructor must create a 62 // FakeRtti object whose tag set includes the corresponding Name 63 // entry, and pass it up to its base class. 64 typedef FakeRttiSupport<BarrierSet, Name> FakeRtti; 65 66 private: 67 FakeRtti _fake_rtti; 68 69 public: 70 // Metafunction mapping a class derived from BarrierSet to the 71 // corresponding Name enum tag. 72 template<typename T> struct GetName; 73 74 // Metafunction mapping a Name enum type to the corresponding 75 // lass derived from BarrierSet. 76 template<BarrierSet::Name T> struct GetType; 77 78 // Note: This is not presently the Name corresponding to the 79 // concrete class of this object. 80 BarrierSet::Name kind() const { return _fake_rtti.concrete_tag(); } 81 82 // Test whether this object is of the type corresponding to bsn. 83 bool is_a(BarrierSet::Name bsn) const { return _fake_rtti.has_tag(bsn); } 84 85 // End of fake RTTI support. 86 87 protected: 88 BarrierSet(const FakeRtti& fake_rtti) : _fake_rtti(fake_rtti) { } 89 ~BarrierSet() { } 90 91 public: 92 // Operations on arrays, or general regions (e.g., for "clone") may be 93 // optimized by some barriers. 94 95 // Below length is the # array elements being written 96 virtual void write_ref_array_pre(oop* dst, int length, 97 bool dest_uninitialized = false) {} 98 virtual void write_ref_array_pre(narrowOop* dst, int length, 99 bool dest_uninitialized = false) {} 100 // Below count is the # array elements being written, starting 101 // at the address "start", which may not necessarily be HeapWord-aligned 102 inline void write_ref_array(HeapWord* start, size_t count); 103 104 // Static versions, suitable for calling from generated code; 105 // count is # array elements being written, starting with "start", 106 // which may not necessarily be HeapWord-aligned. 107 static void static_write_ref_array_pre(HeapWord* start, size_t count); 108 static void static_write_ref_array_post(HeapWord* start, size_t count); 109 110 protected: 111 virtual void write_ref_array_work(MemRegion mr) = 0; 112 113 public: 114 // (For efficiency reasons, this operation is specialized for certain 115 // barrier types. Semantically, it should be thought of as a call to the 116 // virtual "_work" function below, which must implement the barrier.) 117 void write_region(MemRegion mr); 118 119 protected: 120 virtual void write_region_work(MemRegion mr) = 0; 121 122 public: 123 // Inform the BarrierSet that the the covered heap region that starts 124 // with "base" has been changed to have the given size (possibly from 0, 125 // for initialization.) 126 virtual void resize_covered_region(MemRegion new_region) = 0; 127 128 // If the barrier set imposes any alignment restrictions on boundaries 129 // within the heap, this function tells whether they are met. 130 virtual bool is_aligned(HeapWord* addr) = 0; 131 132 // Print a description of the memory for the barrier set 133 virtual void print_on(outputStream* st) const = 0; 134 135 static void set_bs(BarrierSet* bs) { _bs = bs; } 136 137 // The AccessBarrier of a BarrierSet subclass is called by the Access API 138 // (cf. oops/access.hpp) to perform decorated accesses. GC implementations 139 // may override these default access operations by declaring an 140 // AccessBarrier class in its BarrierSet. Its accessors will then be 141 // automatically resolved at runtime. 142 // 143 // In order to register a new FooBarrierSet::AccessBarrier with the Access API, 144 // the following steps should be taken: 145 // 1) Provide an enum "name" for the BarrierSet in barrierSetConfig.hpp 146 // 2) Make sure the barrier set headers are included from barrierSetConfig.inline.hpp 147 // 3) Provide specializations for BarrierSet::GetName and BarrierSet::GetType. 148 template <DecoratorSet decorators, typename BarrierSetT> 149 class AccessBarrier: protected RawAccessBarrier<decorators> { 150 private: 151 typedef RawAccessBarrier<decorators> Raw; 152 153 public: 154 // Primitive heap accesses. These accessors get resolved when 155 // IN_HEAP is set (e.g. when using the HeapAccess API), it is 156 // not an oop_* overload, and the barrier strength is AS_NORMAL. 157 template <typename T> 158 static T load_in_heap(T* addr) { 159 return Raw::template load<T>(addr); 160 } 161 162 template <typename T> 163 static T load_in_heap_at(oop base, ptrdiff_t offset) { 164 return Raw::template load_at<T>(base, offset); 165 } 166 167 template <typename T> 168 static void store_in_heap(T* addr, T value) { 169 Raw::store(addr, value); 170 } 171 172 template <typename T> 173 static void store_in_heap_at(oop base, ptrdiff_t offset, T value) { 174 Raw::store_at(base, offset, value); 175 } 176 177 template <typename T> 178 static T atomic_cmpxchg_in_heap(T new_value, T* addr, T compare_value) { 179 return Raw::atomic_cmpxchg(new_value, addr, compare_value); 180 } 181 182 template <typename T> 183 static T atomic_cmpxchg_in_heap_at(T new_value, oop base, ptrdiff_t offset, T compare_value) { 184 return Raw::oop_atomic_cmpxchg_at(new_value, base, offset, compare_value); 185 } 186 187 template <typename T> 188 static T atomic_xchg_in_heap(T new_value, T* addr) { 189 return Raw::atomic_xchg(new_value, addr); 190 } 191 192 template <typename T> 193 static T atomic_xchg_in_heap_at(T new_value, oop base, ptrdiff_t offset) { 194 return Raw::atomic_xchg_at(new_value, base, offset); 195 } 196 197 template <typename T> 198 static bool arraycopy_in_heap(arrayOop src_obj, arrayOop dst_obj, T* src, T* dst, size_t length) { 199 return Raw::arraycopy(src_obj, dst_obj, src, dst, length); 200 } 201 202 // Heap oop accesses. These accessors get resolved when 203 // IN_HEAP is set (e.g. when using the HeapAccess API), it is 204 // an oop_* overload, and the barrier strength is AS_NORMAL. 205 template <typename T> 206 static oop oop_load_in_heap(T* addr) { 207 return Raw::template oop_load<oop>(addr); 208 } 209 210 static oop oop_load_in_heap_at(oop base, ptrdiff_t offset) { 211 return Raw::template oop_load_at<oop>(base, offset); 212 } 213 214 template <typename T> 215 static void oop_store_in_heap(T* addr, oop value) { 216 Raw::oop_store(addr, value); 217 } 218 219 static void oop_store_in_heap_at(oop base, ptrdiff_t offset, oop value) { 220 Raw::oop_store_at(base, offset, value); 221 } 222 223 template <typename T> 224 static oop oop_atomic_cmpxchg_in_heap(oop new_value, T* addr, oop compare_value) { 225 return Raw::oop_atomic_cmpxchg(new_value, addr, compare_value); 226 } 227 228 static oop oop_atomic_cmpxchg_in_heap_at(oop new_value, oop base, ptrdiff_t offset, oop compare_value) { 229 return Raw::oop_atomic_cmpxchg_at(new_value, base, offset, compare_value); 230 } 231 232 template <typename T> 233 static oop oop_atomic_xchg_in_heap(oop new_value, T* addr) { 234 return Raw::oop_atomic_xchg(new_value, addr); 235 } 236 237 static oop oop_atomic_xchg_in_heap_at(oop new_value, oop base, ptrdiff_t offset) { 238 return Raw::oop_atomic_xchg_at(new_value, base, offset); 239 } 240 241 template <typename T> 242 static bool oop_arraycopy_in_heap(arrayOop src_obj, arrayOop dst_obj, T* src, T* dst, size_t length) { 243 return Raw::oop_arraycopy(src_obj, dst_obj, src, dst, length); 244 } 245 246 // Off-heap oop accesses. These accessors get resolved when 247 // IN_HEAP is not set (e.g. when using the RootAccess API), it is 248 // an oop* overload, and the barrier strength is AS_NORMAL. 249 template <typename T> 250 static oop oop_load_not_in_heap(T* addr) { 251 return Raw::template oop_load<oop>(addr); 252 } 253 254 template <typename T> 255 static void oop_store_not_in_heap(T* addr, oop value) { 256 Raw::oop_store(addr, value); 257 } 258 259 template <typename T> 260 static oop oop_atomic_cmpxchg_not_in_heap(oop new_value, T* addr, oop compare_value) { 261 return Raw::oop_atomic_cmpxchg(new_value, addr, compare_value); 262 } 263 264 template <typename T> 265 static oop oop_atomic_xchg_not_in_heap(oop new_value, T* addr) { 266 return Raw::oop_atomic_xchg(new_value, addr); 267 } 268 269 // Clone barrier support 270 static void clone_in_heap(oop src, oop dst, size_t size) { 271 Raw::clone(src, dst, size); 272 } 273 }; 274 }; 275 276 template<typename T> 277 inline T* barrier_set_cast(BarrierSet* bs) { 278 assert(bs->is_a(BarrierSet::GetName<T>::value), "wrong type of barrier set"); 279 return static_cast<T*>(bs); 280 } 281 282 #endif // SHARE_VM_GC_SHARED_BARRIERSET_HPP