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.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
8 *
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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).
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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