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