1 /*
2 * Copyright (c) 2000, 2017, 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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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).
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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 "asm/register.hpp"
34 #include "utilities/fakeRttiSupport.hpp"
35
36 // This class provides the interface between a barrier implementation and
37 // the rest of the system.
38
39 class MacroAssembler;
40
41 class BarrierSet: public CHeapObj<mtGC> {
42 friend class VMStructs;
43
44 static BarrierSet* _bs;
45
46 public:
47 enum Name {
48 #define BARRIER_SET_DECLARE_BS_ENUM(bs_name) bs_name ,
49 FOR_EACH_BARRIER_SET_DO(BARRIER_SET_DECLARE_BS_ENUM)
50 #undef BARRIER_SET_DECLARE_BS_ENUM
51 UnknownBS
52 };
53
54 static BarrierSet* barrier_set() { return _bs; }
55
56 protected:
57 // Fake RTTI support. For a derived class T to participate
58 // - T must have a corresponding Name entry.
59 // - GetName<T> must be specialized to return the corresponding Name
60 // entry.
61 // - If T is a base class, the constructor must have a FakeRtti
62 // parameter and pass it up to its base class, with the tag set
63 // augmented with the corresponding Name entry.
64 // - If T is a concrete class, the constructor must create a
65 // FakeRtti object whose tag set includes the corresponding Name
66 // entry, and pass it up to its base class.
67 typedef FakeRttiSupport<BarrierSet, Name> FakeRtti;
68
69 private:
70 FakeRtti _fake_rtti;
71
72 public:
73 // Metafunction mapping a class derived from BarrierSet to the
74 // corresponding Name enum tag.
75 template<typename T> struct GetName;
76
77 // Metafunction mapping a Name enum type to the corresponding
78 // lass derived from BarrierSet.
79 template<BarrierSet::Name T> struct GetType;
80
81 // Note: This is not presently the Name corresponding to the
82 // concrete class of this object.
83 BarrierSet::Name kind() const { return _fake_rtti.concrete_tag(); }
84
85 // Test whether this object is of the type corresponding to bsn.
86 bool is_a(BarrierSet::Name bsn) const { return _fake_rtti.has_tag(bsn); }
87
88 // End of fake RTTI support.
89
90 protected:
91 BarrierSet(const FakeRtti& fake_rtti) : _fake_rtti(fake_rtti) { }
92 ~BarrierSet() { }
93
94 public:
95 // Operations on arrays, or general regions (e.g., for "clone") may be
96 // optimized by some barriers.
97
98 // Below length is the # array elements being written
99 virtual void write_ref_array_pre(oop* dst, int length,
100 bool dest_uninitialized = false) {}
101 virtual void write_ref_array_pre(narrowOop* dst, int length,
102 bool dest_uninitialized = false) {}
103 // Below count is the # array elements being written, starting
104 // at the address "start", which may not necessarily be HeapWord-aligned
105 virtual void write_ref_array(HeapWord* start, size_t count);
106
107 // Static versions, suitable for calling from generated code;
108 // count is # array elements being written, starting with "start",
109 // which may not necessarily be HeapWord-aligned.
110 static void static_write_ref_array_pre(HeapWord* start, size_t count);
111 static void static_write_ref_array_post(HeapWord* start, size_t count);
112
113 protected:
114 virtual void write_ref_array_work(MemRegion mr) = 0;
115
116 public:
117 // (For efficiency reasons, this operation is specialized for certain
118 // barrier types. Semantically, it should be thought of as a call to the
119 // virtual "_work" function below, which must implement the barrier.)
120 void write_region(MemRegion mr);
121
122 protected:
123 virtual void write_region_work(MemRegion mr) = 0;
124
125 public:
126 // Inform the BarrierSet that the the covered heap region that starts
127 // with "base" has been changed to have the given size (possibly from 0,
128 // for initialization.)
129 virtual void resize_covered_region(MemRegion new_region) = 0;
130
131 // If the barrier set imposes any alignment restrictions on boundaries
132 // within the heap, this function tells whether they are met.
133 virtual bool is_aligned(HeapWord* addr) = 0;
134
135 // Print a description of the memory for the barrier set
136 virtual void print_on(outputStream* st) const = 0;
137
138 static void set_bs(BarrierSet* bs) { _bs = bs; }
139
140 virtual oop read_barrier(oop src) {
141 return src;
142 }
143 virtual oop write_barrier(oop src) {
144 return src;
145 }
146 virtual oop storeval_barrier(oop src) {
147 return src;
148 }
149
150 virtual void keep_alive_barrier(oop obj) {
151 // Default impl does nothing.
152 }
153
154 virtual bool obj_equals(oop obj1, oop obj2);
155
156 virtual bool obj_equals(narrowOop obj1, narrowOop obj2);
157
158 #ifdef ASSERT
159 virtual void verify_safe_oop(oop p);
160 virtual void verify_safe_oop(narrowOop p);
161 #endif
162
163 #ifndef CC_INTERP
164 virtual void interpreter_read_barrier(MacroAssembler* masm, Register dst) {
165 // Default implementation does nothing.
166 }
167
168 virtual void interpreter_read_barrier_not_null(MacroAssembler* masm, Register dst) {
169 // Default implementation does nothing.
170 }
171
172 virtual void interpreter_write_barrier(MacroAssembler* masm, Register dst) {
173 // Default implementation does nothing.
174 }
175 virtual void interpreter_storeval_barrier(MacroAssembler* masm, Register dst, Register tmp) {
176 // Default implementation does nothing.
177 }
178 virtual void asm_acmp_barrier(MacroAssembler* masm, Register op1, Register op2) {
179 // Default implementation does nothing.
180 }
181 #endif
182
183 // The AccessBarrier of a BarrierSet subclass is called by the Access API
184 // (cf. oops/access.hpp) to perform decorated accesses. GC implementations
185 // may override these default access operations by declaring an
186 // AccessBarrier class in its BarrierSet. Its accessors will then be
187 // automatically resolved at runtime.
188 //
189 // In order to register a new FooBarrierSet::AccessBarrier with the Access API,
190 // the following steps should be taken:
191 // 1) Provide an enum "name" for the BarrierSet in barrierSetConfig.hpp
192 // 2) Make sure the barrier set headers are included from barrierSetConfig.inline.hpp
193 // 3) Provide specializations for BarrierSet::GetName and BarrierSet::GetType.
194 template <DecoratorSet decorators, typename BarrierSetT>
195 class AccessBarrier: protected RawAccessBarrier<decorators> {
196 protected:
197 typedef RawAccessBarrier<decorators> Raw;
198 typedef typename BarrierSetT::template AccessBarrier<decorators> CRTPAccessBarrier;
199
200 public:
201 // Primitive heap accesses. These accessors get resolved when
202 // IN_HEAP is set (e.g. when using the HeapAccess API), it is
203 // not an oop_* overload, and the barrier strength is AS_NORMAL.
204 template <typename T>
205 static T load_in_heap(T* addr) {
206 return Raw::template load<T>(addr);
207 }
208
209 template <typename T>
210 static T load_in_heap_at(oop base, ptrdiff_t offset) {
211 return Raw::template load_at<T>(base, offset);
212 }
213
214 template <typename T>
215 static void store_in_heap(T* addr, T value) {
216 Raw::store(addr, value);
217 }
218
219 template <typename T>
220 static void store_in_heap_at(oop base, ptrdiff_t offset, T value) {
221 Raw::store_at(base, offset, value);
222 }
223
224 template <typename T>
225 static T atomic_cmpxchg_in_heap(T new_value, T* addr, T compare_value) {
226 return Raw::atomic_cmpxchg(new_value, addr, compare_value);
227 }
228
229 template <typename T>
230 static T atomic_cmpxchg_in_heap_at(T new_value, oop base, ptrdiff_t offset, T compare_value) {
231 return Raw::oop_atomic_cmpxchg_at(new_value, base, offset, compare_value);
232 }
233
234 template <typename T>
235 static T atomic_xchg_in_heap(T new_value, T* addr) {
236 return Raw::atomic_xchg(new_value, addr);
237 }
238
239 template <typename T>
240 static T atomic_xchg_in_heap_at(T new_value, oop base, ptrdiff_t offset) {
241 return Raw::atomic_xchg_at(new_value, base, offset);
242 }
243
244 template <typename T>
245 static bool arraycopy_in_heap(arrayOop src_obj, arrayOop dst_obj, T* src, T* dst, size_t length) {
246 return Raw::arraycopy(src, dst, length);
247 }
248
249 // Heap oop accesses. These accessors get resolved when
250 // IN_HEAP is set (e.g. when using the HeapAccess API), it is
251 // an oop_* overload, and the barrier strength is AS_NORMAL.
252 template <typename T>
253 static oop oop_load_in_heap(T* addr) {
254 return Raw::template oop_load<oop>(addr);
255 }
256
257 static oop oop_load_in_heap_at(oop base, ptrdiff_t offset) {
258 return Raw::template oop_load_at<oop>(base, offset);
259 }
260
261 template <typename T>
262 static void oop_store_in_heap(T* addr, oop value) {
263 Raw::oop_store(addr, value);
264 }
265
266 static void oop_store_in_heap_at(oop base, ptrdiff_t offset, oop value) {
267 Raw::oop_store_at(base, offset, value);
268 }
269
270 template <typename T>
271 static oop oop_atomic_cmpxchg_in_heap(oop new_value, T* addr, oop compare_value) {
272 return Raw::oop_atomic_cmpxchg(new_value, addr, compare_value);
273 }
274
275 static oop oop_atomic_cmpxchg_in_heap_at(oop new_value, oop base, ptrdiff_t offset, oop compare_value) {
276 return Raw::oop_atomic_cmpxchg_at(new_value, base, offset, compare_value);
277 }
278
279 template <typename T>
280 static oop oop_atomic_xchg_in_heap(oop new_value, T* addr) {
281 return Raw::oop_atomic_xchg(new_value, addr);
282 }
283
284 static oop oop_atomic_xchg_in_heap_at(oop new_value, oop base, ptrdiff_t offset) {
285 return Raw::oop_atomic_xchg_at(new_value, base, offset);
286 }
287
288 template <typename T>
289 static bool oop_arraycopy_in_heap(arrayOop src_obj, arrayOop dst_obj, T* src, T* dst, size_t length) {
290 return Raw::oop_arraycopy(src_obj, dst_obj, src, dst, length);
291 }
292
293 // Off-heap oop accesses. These accessors get resolved when
294 // IN_HEAP is not set (e.g. when using the RootAccess API), it is
295 // an oop* overload, and the barrier strength is AS_NORMAL.
296 template <typename T>
297 static oop oop_load_not_in_heap(T* addr) {
298 return Raw::template oop_load<oop>(addr);
299 }
300
301 template <typename T>
302 static void oop_store_not_in_heap(T* addr, oop value) {
303 Raw::oop_store(addr, value);
304 }
305
306 template <typename T>
307 static oop oop_atomic_cmpxchg_not_in_heap(oop new_value, T* addr, oop compare_value) {
308 return Raw::oop_atomic_cmpxchg(new_value, addr, compare_value);
309 }
310
311 template <typename T>
312 static oop oop_atomic_xchg_not_in_heap(oop new_value, T* addr) {
313 return Raw::oop_atomic_xchg(new_value, addr);
314 }
315
316 // Clone barrier support
317 static void clone_in_heap(oop src, oop dst, size_t size) {
318 Raw::clone(src, dst, size);
319 }
320 };
321 };
322
323 template<typename T>
324 inline T* barrier_set_cast(BarrierSet* bs) {
325 assert(bs->is_a(BarrierSet::GetName<T>::value), "wrong type of barrier set");
326 return static_cast<T*>(bs);
327 }
328
329 #endif // SHARE_VM_GC_SHARED_BARRIERSET_HPP