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 void arraycopy_in_heap(arrayOop src_obj, arrayOop dst_obj, T* src, T* dst, size_t length) {
193 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