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 flush_deferred_barriers(JavaThread* thread) {} 119 virtual void make_parsable(JavaThread* thread) {} 120 121 protected: 122 virtual void write_ref_array_work(MemRegion mr) = 0; 123 124 public: 125 // Inform the BarrierSet that the the covered heap region that starts 126 // with "base" has been changed to have the given size (possibly from 0, 127 // for initialization.) 128 virtual void resize_covered_region(MemRegion new_region) = 0; 129 130 // If the barrier set imposes any alignment restrictions on boundaries 131 // within the heap, this function tells whether they are met. 132 virtual bool is_aligned(HeapWord* addr) = 0; 133 134 // Print a description of the memory for the barrier set 135 virtual void print_on(outputStream* st) const = 0; 136 137 static void set_bs(BarrierSet* bs) { _bs = bs; } 138 139 // The AccessBarrier of a BarrierSet subclass is called by the Access API 140 // (cf. oops/access.hpp) to perform decorated accesses. GC implementations 141 // may override these default access operations by declaring an 142 // AccessBarrier class in its BarrierSet. Its accessors will then be 143 // automatically resolved at runtime. 144 // 145 // In order to register a new FooBarrierSet::AccessBarrier with the Access API, 146 // the following steps should be taken: 147 // 1) Provide an enum "name" for the BarrierSet in barrierSetConfig.hpp 148 // 2) Make sure the barrier set headers are included from barrierSetConfig.inline.hpp 149 // 3) Provide specializations for BarrierSet::GetName and BarrierSet::GetType. 150 template <DecoratorSet decorators, typename BarrierSetT> 151 class AccessBarrier: protected RawAccessBarrier<decorators> { 152 private: 153 typedef RawAccessBarrier<decorators> Raw; 154 155 public: 156 // Primitive heap accesses. These accessors get resolved when 157 // IN_HEAP is set (e.g. when using the HeapAccess API), it is 158 // not an oop_* overload, and the barrier strength is AS_NORMAL. 159 template <typename T> 160 static T load_in_heap(T* addr) { 161 return Raw::template load<T>(addr); 162 } 163 164 template <typename T> 165 static T load_in_heap_at(oop base, ptrdiff_t offset) { 166 return Raw::template load_at<T>(base, offset); 167 } 168 169 template <typename T> 170 static void store_in_heap(T* addr, T value) { 171 Raw::store(addr, value); 172 } 173 174 template <typename T> 175 static void store_in_heap_at(oop base, ptrdiff_t offset, T value) { 176 Raw::store_at(base, offset, value); 177 } 178 179 template <typename T> 180 static T atomic_cmpxchg_in_heap(T new_value, T* addr, T compare_value) { 181 return Raw::atomic_cmpxchg(new_value, addr, compare_value); 182 } 183 184 template <typename T> 185 static T atomic_cmpxchg_in_heap_at(T new_value, oop base, ptrdiff_t offset, T compare_value) { 186 return Raw::oop_atomic_cmpxchg_at(new_value, base, offset, compare_value); 187 } 188 189 template <typename T> 190 static T atomic_xchg_in_heap(T new_value, T* addr) { 191 return Raw::atomic_xchg(new_value, addr); 192 } 193 194 template <typename T> 195 static T atomic_xchg_in_heap_at(T new_value, oop base, ptrdiff_t offset) { 196 return Raw::atomic_xchg_at(new_value, base, offset); 197 } 198 199 template <typename T> 200 static bool arraycopy_in_heap(arrayOop src_obj, arrayOop dst_obj, T* src, T* dst, size_t length) { 201 return Raw::arraycopy(src_obj, dst_obj, src, dst, length); 202 } 203 204 // Heap oop accesses. These accessors get resolved when 205 // IN_HEAP is set (e.g. when using the HeapAccess API), it is 206 // an oop_* overload, and the barrier strength is AS_NORMAL. 207 template <typename T> 208 static oop oop_load_in_heap(T* addr) { 209 return Raw::template oop_load<oop>(addr); 210 } 211 212 static oop oop_load_in_heap_at(oop base, ptrdiff_t offset) { 213 return Raw::template oop_load_at<oop>(base, offset); 214 } 215 216 template <typename T> 217 static void oop_store_in_heap(T* addr, oop value) { 218 Raw::oop_store(addr, value); 219 } 220 221 static void oop_store_in_heap_at(oop base, ptrdiff_t offset, oop value) { 222 Raw::oop_store_at(base, offset, value); 223 } 224 225 template <typename T> 226 static oop oop_atomic_cmpxchg_in_heap(oop new_value, T* addr, oop compare_value) { 227 return Raw::oop_atomic_cmpxchg(new_value, addr, compare_value); 228 } 229 230 static oop oop_atomic_cmpxchg_in_heap_at(oop new_value, oop base, ptrdiff_t offset, oop compare_value) { 231 return Raw::oop_atomic_cmpxchg_at(new_value, base, offset, compare_value); 232 } 233 234 template <typename T> 235 static oop oop_atomic_xchg_in_heap(oop new_value, T* addr) { 236 return Raw::oop_atomic_xchg(new_value, addr); 237 } 238 239 static oop oop_atomic_xchg_in_heap_at(oop new_value, oop base, ptrdiff_t offset) { 240 return Raw::oop_atomic_xchg_at(new_value, base, offset); 241 } 242 243 template <typename T> 244 static bool oop_arraycopy_in_heap(arrayOop src_obj, arrayOop dst_obj, T* src, T* dst, size_t length) { 245 return Raw::oop_arraycopy(src_obj, dst_obj, src, dst, length); 246 } 247 248 // Off-heap oop accesses. These accessors get resolved when 249 // IN_HEAP is not set (e.g. when using the RootAccess API), it is 250 // an oop* overload, and the barrier strength is AS_NORMAL. 251 template <typename T> 252 static oop oop_load_not_in_heap(T* addr) { 253 return Raw::template oop_load<oop>(addr); 254 } 255 256 template <typename T> 257 static void oop_store_not_in_heap(T* addr, oop value) { 258 Raw::oop_store(addr, value); 259 } 260 261 template <typename T> 262 static oop oop_atomic_cmpxchg_not_in_heap(oop new_value, T* addr, oop compare_value) { 263 return Raw::oop_atomic_cmpxchg(new_value, addr, compare_value); 264 } 265 266 template <typename T> 267 static oop oop_atomic_xchg_not_in_heap(oop new_value, T* addr) { 268 return Raw::oop_atomic_xchg(new_value, addr); 269 } 270 271 // Clone barrier support 272 static void clone_in_heap(oop src, oop dst, size_t size) { 273 Raw::clone(src, dst, size); 274 } 275 }; 276 }; 277 278 template<typename T> 279 inline T* barrier_set_cast(BarrierSet* bs) { 280 assert(bs->is_a(BarrierSet::GetName<T>::value), "wrong type of barrier set"); 281 return static_cast<T*>(bs); 282 } 283 284 #endif // SHARE_VM_GC_SHARED_BARRIERSET_HPP