1 /*
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  6  * under the terms of the GNU General Public License version 2 only, as
  7  * published by the Free Software Foundation.
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  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).
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 24 
 25 #ifndef SHARE_GC_SHARED_BARRIERSET_HPP
 26 #define SHARE_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 #include "utilities/macros.hpp"
 35 
 36 class BarrierSetAssembler;
 37 class BarrierSetC1;
 38 class BarrierSetC2;
 39 class BarrierSetNMethod;
 40 class JavaThread;
 41 
 42 // This class provides the interface between a barrier implementation and
 43 // the rest of the system.
 44 
 45 class BarrierSet: public CHeapObj<mtGC> {
 46   friend class VMStructs;
 47 
 48   static BarrierSet* _barrier_set;
 49 
 50 public:
 51   enum Name {
 52 #define BARRIER_SET_DECLARE_BS_ENUM(bs_name) bs_name ,
 53     FOR_EACH_BARRIER_SET_DO(BARRIER_SET_DECLARE_BS_ENUM)
 54 #undef BARRIER_SET_DECLARE_BS_ENUM
 55     UnknownBS
 56   };
 57 
 58 protected:
 59   // Fake RTTI support.  For a derived class T to participate
 60   // - T must have a corresponding Name entry.
 61   // - GetName<T> must be specialized to return the corresponding Name
 62   //   entry.
 63   // - If T is a base class, the constructor must have a FakeRtti
 64   //   parameter and pass it up to its base class, with the tag set
 65   //   augmented with the corresponding Name entry.
 66   // - If T is a concrete class, the constructor must create a
 67   //   FakeRtti object whose tag set includes the corresponding Name
 68   //   entry, and pass it up to its base class.
 69   typedef FakeRttiSupport<BarrierSet, Name> FakeRtti;
 70 
 71 private:
 72   FakeRtti _fake_rtti;
 73   BarrierSetAssembler* _barrier_set_assembler;
 74   BarrierSetC1* _barrier_set_c1;
 75   BarrierSetC2* _barrier_set_c2;
 76   BarrierSetNMethod* _barrier_set_nmethod;
 77 
 78 public:
 79   // Metafunction mapping a class derived from BarrierSet to the
 80   // corresponding Name enum tag.
 81   template<typename T> struct GetName;
 82 
 83   // Metafunction mapping a Name enum type to the corresponding
 84   // lass derived from BarrierSet.
 85   template<BarrierSet::Name T> struct GetType;
 86 
 87   // Note: This is not presently the Name corresponding to the
 88   // concrete class of this object.
 89   BarrierSet::Name kind() const { return _fake_rtti.concrete_tag(); }
 90 
 91   // Test whether this object is of the type corresponding to bsn.
 92   bool is_a(BarrierSet::Name bsn) const { return _fake_rtti.has_tag(bsn); }
 93 
 94   // End of fake RTTI support.
 95 
 96 protected:
 97   BarrierSet(BarrierSetAssembler* barrier_set_assembler,
 98              BarrierSetC1* barrier_set_c1,
 99              BarrierSetC2* barrier_set_c2,
100              BarrierSetNMethod* barrier_set_nmethod,
101              const FakeRtti& fake_rtti) :
102     _fake_rtti(fake_rtti),
103     _barrier_set_assembler(barrier_set_assembler),
104     _barrier_set_c1(barrier_set_c1),
105     _barrier_set_c2(barrier_set_c2),
106     _barrier_set_nmethod(barrier_set_nmethod) {}
107   ~BarrierSet() { }
108 
109   template <class BarrierSetAssemblerT>
110   static BarrierSetAssembler* make_barrier_set_assembler() {
111     return NOT_ZERO(new BarrierSetAssemblerT()) ZERO_ONLY(NULL);
112   }
113 
114   template <class BarrierSetC1T>
115   static BarrierSetC1* make_barrier_set_c1() {
116     return COMPILER1_PRESENT(new BarrierSetC1T()) NOT_COMPILER1(NULL);
117   }
118 
119   template <class BarrierSetC2T>
120   static BarrierSetC2* make_barrier_set_c2() {
121     return COMPILER2_PRESENT(new BarrierSetC2T()) NOT_COMPILER2(NULL);
122   }
123 
124 public:
125   // Support for optimizing compilers to call the barrier set on slow path allocations
126   // that did not enter a TLAB. Used for e.g. ReduceInitialCardMarks.
127   // The allocation is safe to use iff it returns true. If not, the slow-path allocation
128   // is redone until it succeeds. This can e.g. prevent allocations from the slow path
129   // to be in old.
130   virtual void on_slowpath_allocation_exit(JavaThread* thread, oop new_obj) {}
131   virtual void on_thread_create(Thread* thread) {}
132   virtual void on_thread_destroy(Thread* thread) {}
133 
134   // These perform BarrierSet-related initialization/cleanup before the thread
135   // is added to or removed from the corresponding set of threads. The
136   // argument thread is the current thread. These are called either holding
137   // the Threads_lock (for a JavaThread) and so not at a safepoint, or holding
138   // the NonJavaThreadsList_lock (for a NonJavaThread) locked by the
139   // caller. That locking ensures the operation is "atomic" with the list
140   // modification wrto operations that hold the NJTList_lock and either also
141   // hold the Threads_lock or are at a safepoint.
142   virtual void on_thread_attach(Thread* thread) {}
143   virtual void on_thread_detach(Thread* thread) {}
144 
145   virtual void make_parsable(JavaThread* thread) {}
146 
147 public:
148   // Print a description of the memory for the barrier set
149   virtual void print_on(outputStream* st) const = 0;
150 
151   static BarrierSet* barrier_set() { return _barrier_set; }
152   static void set_barrier_set(BarrierSet* barrier_set);
153 
154   BarrierSetAssembler* barrier_set_assembler() {
155     assert(_barrier_set_assembler != NULL, "should be set");
156     return _barrier_set_assembler;
157   }
158 
159   BarrierSetC1* barrier_set_c1() {
160     assert(_barrier_set_c1 != NULL, "should be set");
161     return _barrier_set_c1;
162   }
163 
164   BarrierSetC2* barrier_set_c2() {
165     assert(_barrier_set_c2 != NULL, "should be set");
166     return _barrier_set_c2;
167   }
168 
169   BarrierSetNMethod* barrier_set_nmethod() {
170     return _barrier_set_nmethod;
171   }
172 
173   // The AccessBarrier of a BarrierSet subclass is called by the Access API
174   // (cf. oops/access.hpp) to perform decorated accesses. GC implementations
175   // may override these default access operations by declaring an
176   // AccessBarrier class in its BarrierSet. Its accessors will then be
177   // automatically resolved at runtime.
178   //
179   // In order to register a new FooBarrierSet::AccessBarrier with the Access API,
180   // the following steps should be taken:
181   // 1) Provide an enum "name" for the BarrierSet in barrierSetConfig.hpp
182   // 2) Make sure the barrier set headers are included from barrierSetConfig.inline.hpp
183   // 3) Provide specializations for BarrierSet::GetName and BarrierSet::GetType.
184   template <DecoratorSet decorators, typename BarrierSetT>
185   class AccessBarrier: protected RawAccessBarrier<decorators> {
186   private:
187     typedef RawAccessBarrier<decorators> Raw;
188 
189   public:
190     // Primitive heap accesses. These accessors get resolved when
191     // IN_HEAP is set (e.g. when using the HeapAccess API), it is
192     // not an oop_* overload, and the barrier strength is AS_NORMAL.
193     template <typename T>
194     static T load_in_heap(T* addr) {
195       return Raw::template load<T>(addr);
196     }
197 
198     template <typename T>
199     static T load_in_heap_at(oop base, ptrdiff_t offset) {
200       return Raw::template load_at<T>(base, offset);
201     }
202 
203     template <typename T>
204     static void store_in_heap(T* addr, T value) {
205       Raw::store(addr, value);
206     }
207 
208     template <typename T>
209     static void store_in_heap_at(oop base, ptrdiff_t offset, T value) {
210       Raw::store_at(base, offset, value);
211     }
212 
213     template <typename T>
214     static T atomic_cmpxchg_in_heap(T* addr, T compare_value, T new_value) {
215       return Raw::atomic_cmpxchg(addr, compare_value, new_value);
216     }
217 
218     template <typename T>
219     static T atomic_cmpxchg_in_heap_at(oop base, ptrdiff_t offset, T compare_value, T new_value) {
220       return Raw::atomic_cmpxchg_at(base, offset, compare_value, new_value);
221     }
222 
223     template <typename T>
224     static T atomic_xchg_in_heap(T* addr, T new_value) {
225       return Raw::atomic_xchg(addr, new_value);
226     }
227 
228     template <typename T>
229     static T atomic_xchg_in_heap_at(oop base, ptrdiff_t offset, T new_value) {
230       return Raw::atomic_xchg_at(base, offset, new_value);
231     }
232 
233     template <typename T>
234     static void arraycopy_in_heap(arrayOop src_obj, size_t src_offset_in_bytes, T* src_raw,
235                                   arrayOop dst_obj, size_t dst_offset_in_bytes, T* dst_raw,
236                                   size_t length) {
237       Raw::arraycopy(src_obj, src_offset_in_bytes, src_raw,
238                      dst_obj, dst_offset_in_bytes, dst_raw,
239                      length);
240     }
241 
242     // Heap oop accesses. These accessors get resolved when
243     // IN_HEAP is set (e.g. when using the HeapAccess API), it is
244     // an oop_* overload, and the barrier strength is AS_NORMAL.
245     template <typename T>
246     static oop oop_load_in_heap(T* addr) {
247       return Raw::template oop_load<oop>(addr);
248     }
249 
250     static oop oop_load_in_heap_at(oop base, ptrdiff_t offset) {
251       return Raw::template oop_load_at<oop>(base, offset);
252     }
253 
254     template <typename T>
255     static void oop_store_in_heap(T* addr, oop value) {
256       Raw::oop_store(addr, value);
257     }
258 
259     static void oop_store_in_heap_at(oop base, ptrdiff_t offset, oop value) {
260       Raw::oop_store_at(base, offset, value);
261     }
262 
263     template <typename T>
264     static oop oop_atomic_cmpxchg_in_heap(T* addr, oop compare_value, oop new_value) {
265       return Raw::oop_atomic_cmpxchg(addr, compare_value, new_value);
266     }
267 
268     static oop oop_atomic_cmpxchg_in_heap_at(oop base, ptrdiff_t offset, oop compare_value, oop new_value) {
269       return Raw::oop_atomic_cmpxchg_at(base, offset, compare_value, new_value);
270     }
271 
272     template <typename T>
273     static oop oop_atomic_xchg_in_heap(T* addr, oop new_value) {
274       return Raw::oop_atomic_xchg(addr, new_value);
275     }
276 
277     static oop oop_atomic_xchg_in_heap_at(oop base, ptrdiff_t offset, oop new_value) {
278       return Raw::oop_atomic_xchg_at(base, offset, new_value);
279     }
280 
281     template <typename T>
282     static bool oop_arraycopy_in_heap(arrayOop src_obj, size_t src_offset_in_bytes, T* src_raw,
283                                       arrayOop dst_obj, size_t dst_offset_in_bytes, T* dst_raw,
284                                       size_t length);
285 
286     // Off-heap oop accesses. These accessors get resolved when
287     // IN_HEAP is not set (e.g. when using the NativeAccess API), it is
288     // an oop* overload, and the barrier strength is AS_NORMAL.
289     template <typename T>
290     static oop oop_load_not_in_heap(T* addr) {
291       return Raw::template oop_load<oop>(addr);
292     }
293 
294     template <typename T>
295     static void oop_store_not_in_heap(T* addr, oop value) {
296       Raw::oop_store(addr, value);
297     }
298 
299     template <typename T>
300     static oop oop_atomic_cmpxchg_not_in_heap(T* addr, oop compare_value, oop new_value) {
301       return Raw::oop_atomic_cmpxchg(addr, compare_value, new_value);
302     }
303 
304     template <typename T>
305     static oop oop_atomic_xchg_not_in_heap(T* addr, oop new_value) {
306       return Raw::oop_atomic_xchg(addr, new_value);
307     }
308 
309     // Clone barrier support
310     static void clone_in_heap(oop src, oop dst, size_t size) {
311       Raw::clone(src, dst, size);
312     }
313   };
314 };
315 
316 template<typename T>
317 inline T* barrier_set_cast(BarrierSet* bs) {
318   assert(bs->is_a(BarrierSet::GetName<T>::value), "wrong type of barrier set");
319   return static_cast<T*>(bs);
320 }
321 
322 #endif // SHARE_GC_SHARED_BARRIERSET_HPP