1 /*
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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
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 24 
 25 #ifndef SHARE_GC_SHARED_MODREFBARRIERSET_INLINE_HPP
 26 #define SHARE_GC_SHARED_MODREFBARRIERSET_INLINE_HPP
 27 
 28 #include "gc/shared/modRefBarrierSet.hpp"
 29 
 30 #include "gc/shared/barrierSet.hpp"
 31 #include "oops/compressedOops.inline.hpp"
 32 #include "oops/objArrayOop.hpp"
 33 #include "oops/oop.hpp"
 34 #include "runtime/thread.hpp"
 35 
 36 class Klass;
 37 
 38 // count is number of array elements being written
 39 void ModRefBarrierSet::write_ref_array(HeapWord* start, size_t count) {
 40   HeapWord* end = (HeapWord*)((char*)start + (count*heapOopSize));
 41   // In the case of compressed oops, start and end may potentially be misaligned;
 42   // so we need to conservatively align the first downward (this is not
 43   // strictly necessary for current uses, but a case of good hygiene and,
 44   // if you will, aesthetics) and the second upward (this is essential for
 45   // current uses) to a HeapWord boundary, so we mark all cards overlapping
 46   // this write. If this evolves in the future to calling a
 47   // logging barrier of narrow oop granularity, like the pre-barrier for G1
 48   // (mentioned here merely by way of example), we will need to change this
 49   // interface, so it is "exactly precise" (if i may be allowed the adverbial
 50   // redundancy for emphasis) and does not include narrow oop slots not
 51   // included in the original write interval.
 52   HeapWord* aligned_start = align_down(start, HeapWordSize);
 53   HeapWord* aligned_end   = align_up  (end,   HeapWordSize);
 54   // If compressed oops were not being used, these should already be aligned
 55   assert(UseCompressedOops || (aligned_start == start && aligned_end == end),
 56          "Expected heap word alignment of start and end");
 57   write_ref_array_work(MemRegion(aligned_start, aligned_end));
 58 }
 59 
 60 template <DecoratorSet decorators, typename BarrierSetT>
 61 template <typename T>
 62 inline void ModRefBarrierSet::AccessBarrier<decorators, BarrierSetT>::
 63 oop_store_in_heap(T* addr, oop value) {
 64   BarrierSetT *bs = barrier_set_cast<BarrierSetT>(barrier_set());
 65   bs->template write_ref_field_pre<decorators>(addr);
 66   Raw::oop_store(addr, value);
 67   bs->template write_ref_field_post<decorators>(addr);
 68 }
 69 
 70 template <DecoratorSet decorators, typename BarrierSetT>
 71 template <typename T>
 72 inline oop ModRefBarrierSet::AccessBarrier<decorators, BarrierSetT>::
 73 oop_atomic_cmpxchg_in_heap(T* addr, oop compare_value, oop new_value) {
 74   BarrierSetT *bs = barrier_set_cast<BarrierSetT>(barrier_set());
 75   bs->template write_ref_field_pre<decorators>(addr);
 76   oop result = Raw::oop_atomic_cmpxchg(addr, compare_value, new_value);
 77   if (result == compare_value) {
 78     bs->template write_ref_field_post<decorators>(addr);
 79   }
 80   return result;
 81 }
 82 
 83 template <DecoratorSet decorators, typename BarrierSetT>
 84 template <typename T>
 85 inline oop ModRefBarrierSet::AccessBarrier<decorators, BarrierSetT>::
 86 oop_atomic_xchg_in_heap(T* addr, oop new_value) {
 87   BarrierSetT *bs = barrier_set_cast<BarrierSetT>(barrier_set());
 88   bs->template write_ref_field_pre<decorators>(addr);
 89   oop result = Raw::oop_atomic_xchg(addr, new_value);
 90   bs->template write_ref_field_post<decorators>(addr);
 91   return result;
 92 }
 93 
 94 template <DecoratorSet decorators, typename BarrierSetT>
 95 template <typename T>
 96 inline bool ModRefBarrierSet::AccessBarrier<decorators, BarrierSetT>::
 97 oop_arraycopy_in_heap(arrayOop src_obj, size_t src_offset_in_bytes, T* src_raw,
 98                       arrayOop dst_obj, size_t dst_offset_in_bytes, T* dst_raw,
 99                       size_t length) {
100   BarrierSetT *bs = barrier_set_cast<BarrierSetT>(barrier_set());
101 
102   src_raw = arrayOopDesc::obj_offset_to_raw(src_obj, src_offset_in_bytes, src_raw);
103   dst_raw = arrayOopDesc::obj_offset_to_raw(dst_obj, dst_offset_in_bytes, dst_raw);
104 
105   if (!HasDecorator<decorators, ARRAYCOPY_CHECKCAST>::value) {
106     // Optimized covariant case
107     bs->write_ref_array_pre(dst_raw, length,
108                             HasDecorator<decorators, IS_DEST_UNINITIALIZED>::value);
109     Raw::oop_arraycopy(nullptr, 0, src_raw, nullptr, 0, dst_raw, length);
110     bs->write_ref_array((HeapWord*)dst_raw, length);
111   } else {
112     assert(dst_obj != nullptr, "better have an actual oop");
113     Klass* bound = objArrayOop(dst_obj)->element_klass();
114     T* from = const_cast<T*>(src_raw);
115     T* end = from + length;
116     for (T* p = dst_raw; from < end; from++, p++) {
117       T element = *from;
118       if (oopDesc::is_instanceof_or_null(CompressedOops::decode(element), bound)) {
119         bs->template write_ref_field_pre<decorators>(p);
120         *p = element;
121       } else {
122         // We must do a barrier to cover the partial copy.
123         const size_t pd = pointer_delta(p, dst_raw, (size_t)heapOopSize);
124         // pointer delta is scaled to number of elements (length field in
125         // objArrayOop) which we assume is 32 bit.
126         assert(pd == (size_t)(int)pd, "length field overflow");
127         bs->write_ref_array((HeapWord*)dst_raw, pd);
128         return false;
129       }
130     }
131     bs->write_ref_array((HeapWord*)dst_raw, length);
132   }
133   return true;
134 }
135 
136 template <DecoratorSet decorators, typename BarrierSetT>
137 inline void ModRefBarrierSet::AccessBarrier<decorators, BarrierSetT>::
138 clone_in_heap(oop src, oop dst, size_t size) {
139   Raw::clone(src, dst, size);
140   BarrierSetT *bs = barrier_set_cast<BarrierSetT>(barrier_set());
141   bs->invalidate(MemRegion((HeapWord*)(void*)dst, size));
142 }
143 
144 #endif // SHARE_GC_SHARED_MODREFBARRIERSET_INLINE_HPP