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