Thu, 07 Apr 2011 09:53:20 -0700
7009266: G1: assert(obj->is_oop_or_null(true )) failed: Error
Summary: A referent object that is only weakly reachable at the start of concurrent marking but is re-attached to the strongly reachable object graph during marking may not be marked as live. This can cause the reference object to be processed prematurely and leave dangling pointers to the referent object. Implement a read barrier for the java.lang.ref.Reference::referent field by intrinsifying the Reference.get() method, and intercepting accesses though JNI, reflection, and Unsafe, so that when a non-null referent object is read it is also logged in an SATB buffer.
Reviewed-by: kvn, iveresov, never, tonyp, dholmes
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25 #ifndef SHARE_VM_OOPS_CPCACHEKLASS_HPP
26 #define SHARE_VM_OOPS_CPCACHEKLASS_HPP
28 #include "oops/arrayKlass.hpp"
29 #include "oops/cpCacheOop.hpp"
30 #include "oops/instanceKlass.hpp"
32 class constantPoolCacheKlass: public Klass {
33 juint _alloc_size; // allocation profiling support
34 public:
35 // Dispatched klass operations
36 bool oop_is_constantPoolCache() const { return true; }
37 int oop_size(oop obj) const;
38 int klass_oop_size() const { return object_size(); }
40 // Allocation
41 DEFINE_ALLOCATE_PERMANENT(constantPoolCacheKlass);
42 constantPoolCacheOop allocate(int length, TRAPS);
43 static klassOop create_klass(TRAPS);
45 // Casting from klassOop
46 static constantPoolCacheKlass* cast(klassOop k) {
47 assert(k->klass_part()->oop_is_constantPoolCache(), "cast to constantPoolCacheKlass");
48 return (constantPoolCacheKlass*)k->klass_part();
49 }
51 // Sizing
52 static int header_size() { return oopDesc::header_size() + sizeof(constantPoolCacheKlass)/HeapWordSize; }
53 int object_size() const { return align_object_size(header_size()); }
55 // Garbage collection
56 void oop_follow_contents(oop obj);
57 int oop_adjust_pointers(oop obj);
59 // Parallel Scavenge and Parallel Old
60 PARALLEL_GC_DECLS
62 // Iterators
63 int oop_oop_iterate(oop obj, OopClosure* blk);
64 int oop_oop_iterate_m(oop obj, OopClosure* blk, MemRegion mr);
66 // Allocation profiling support
67 juint alloc_size() const { return _alloc_size; }
68 void set_alloc_size(juint n) { _alloc_size = n; }
70 // Printing
71 void oop_print_value_on(oop obj, outputStream* st);
72 void oop_print_on(oop obj, outputStream* st);
74 // Verification
75 const char* internal_name() const;
76 void oop_verify_on(oop obj, outputStream* st);
77 };
79 #endif // SHARE_VM_OOPS_CPCACHEKLASS_HPP