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_METHODKLASS_HPP
26 #define SHARE_VM_OOPS_METHODKLASS_HPP
28 #include "oops/klass.hpp"
29 #include "oops/klassOop.hpp"
30 #include "oops/methodOop.hpp"
32 // a methodKlass is the klass of a methodOop
34 class methodKlass : public Klass {
35 friend class VMStructs;
36 private:
37 juint _alloc_size; // allocation profiling support
38 public:
39 // Testing
40 bool oop_is_method() const { return true; }
42 // Allocation
43 DEFINE_ALLOCATE_PERMANENT(methodKlass);
44 methodOop allocate(constMethodHandle xconst, AccessFlags access_flags,
45 TRAPS);
46 static klassOop create_klass(TRAPS);
48 // Sizing
49 int oop_size(oop obj) const;
50 int klass_oop_size() const { return object_size(); }
52 // Casting from klassOop
53 static methodKlass* cast(klassOop k) {
54 assert(k->klass_part()->oop_is_method(), "cast to methodKlass");
55 return (methodKlass*) k->klass_part();
56 }
58 // Sizing
59 static int header_size() { return oopDesc::header_size() + sizeof(methodKlass)/HeapWordSize; }
60 int object_size() const { return align_object_size(header_size()); }
62 // Garbage collection
63 void oop_follow_contents(oop obj);
64 int oop_adjust_pointers(oop obj);
65 bool oop_is_parsable(oop obj) const;
67 // Parallel Scavenge and Parallel Old
68 PARALLEL_GC_DECLS
70 // Allocation profiling support
71 juint alloc_size() const { return _alloc_size; }
72 void set_alloc_size(juint n) { _alloc_size = n; }
74 // Iterators
75 int oop_oop_iterate(oop obj, OopClosure* blk);
76 int oop_oop_iterate_m(oop obj, OopClosure* blk, MemRegion mr);
78 public:
79 // Printing
80 void oop_print_value_on(oop obj, outputStream* st);
81 #ifndef PRODUCT
82 void oop_print_on (oop obj, outputStream* st);
83 #endif //PRODUCT
85 // Verify operations
86 const char* internal_name() const;
87 void oop_verify_on(oop obj, outputStream* st);
88 bool oop_partially_loaded(oop obj) const;
89 void oop_set_partially_loaded(oop obj);
90 };
92 #endif // SHARE_VM_OOPS_METHODKLASS_HPP