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_CONSTANTPOOLKLASS_HPP
26 #define SHARE_VM_OOPS_CONSTANTPOOLKLASS_HPP
28 #include "oops/arrayKlass.hpp"
29 #include "oops/instanceKlass.hpp"
31 // A constantPoolKlass is the klass of a constantPoolOop
33 class constantPoolKlass : public Klass {
34 juint _alloc_size; // allocation profiling support
35 public:
36 // Dispatched klass operations
37 bool oop_is_constantPool() const { return true; }
38 int oop_size(oop obj) const;
39 int klass_oop_size() const { return object_size(); }
41 // Allocation
42 DEFINE_ALLOCATE_PERMANENT(constantPoolKlass);
43 constantPoolOop allocate(int length, bool is_conc_safe, TRAPS);
44 static klassOop create_klass(TRAPS);
46 // Casting from klassOop
47 static constantPoolKlass* cast(klassOop k) {
48 assert(k->klass_part()->oop_is_constantPool(), "cast to constantPoolKlass");
49 return (constantPoolKlass*) k->klass_part();
50 }
52 // Sizing
53 static int header_size() { return oopDesc::header_size() + sizeof(constantPoolKlass)/HeapWordSize; }
54 int object_size() const { return align_object_size(header_size()); }
56 // Garbage collection
57 // Returns true is the object is safe for GC concurrent processing.
58 virtual bool oop_is_conc_safe(oop obj) const;
59 void oop_follow_contents(oop obj);
60 int oop_adjust_pointers(oop obj);
62 // Parallel Scavenge and Parallel Old
63 PARALLEL_GC_DECLS
65 // Iterators
66 int oop_oop_iterate(oop obj, OopClosure* blk);
67 int oop_oop_iterate_m(oop obj, OopClosure* blk, MemRegion mr);
69 // Allocation profiling support
70 juint alloc_size() const { return _alloc_size; }
71 void set_alloc_size(juint n) { _alloc_size = n; }
73 // Printing
74 void oop_print_value_on(oop obj, outputStream* st);
75 void oop_print_on(oop obj, outputStream* st);
77 // Verification
78 const char* internal_name() const;
79 void oop_verify_on(oop obj, outputStream* st);
80 // tells whether obj is partially constructed (gc during class loading)
81 bool oop_partially_loaded(oop obj) const;
82 void oop_set_partially_loaded(oop obj);
83 #ifndef PRODUCT
84 // Compile the world support
85 static void preload_and_initialize_all_classes(oop constant_pool, TRAPS);
86 #endif
87 };
89 #endif // SHARE_VM_OOPS_CONSTANTPOOLKLASS_HPP