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_OBJARRAYKLASS_HPP
26 #define SHARE_VM_OOPS_OBJARRAYKLASS_HPP
28 #include "memory/specialized_oop_closures.hpp"
29 #include "oops/arrayKlass.hpp"
30 #include "oops/instanceKlass.hpp"
32 // objArrayKlass is the klass for objArrays
34 class objArrayKlass : public arrayKlass {
35 friend class VMStructs;
36 private:
37 klassOop _element_klass; // The klass of the elements of this array type
38 klassOop _bottom_klass; // The one-dimensional type (instanceKlass or typeArrayKlass)
39 public:
40 // Instance variables
41 klassOop element_klass() const { return _element_klass; }
42 void set_element_klass(klassOop k) { oop_store_without_check((oop*) &_element_klass, (oop) k); }
43 oop* element_klass_addr() { return (oop*)&_element_klass; }
45 klassOop bottom_klass() const { return _bottom_klass; }
46 void set_bottom_klass(klassOop k) { oop_store_without_check((oop*) &_bottom_klass, (oop) k); }
47 oop* bottom_klass_addr() { return (oop*)&_bottom_klass; }
49 // Compiler/Interpreter offset
50 static int element_klass_offset_in_bytes() { return offset_of(objArrayKlass, _element_klass); }
52 // Dispatched operation
53 bool can_be_primary_super_slow() const;
54 objArrayOop compute_secondary_supers(int num_extra_slots, TRAPS);
55 bool compute_is_subtype_of(klassOop k);
56 bool oop_is_objArray_slow() const { return true; }
57 int oop_size(oop obj) const;
58 int klass_oop_size() const { return object_size(); }
60 // Allocation
61 DEFINE_ALLOCATE_PERMANENT(objArrayKlass);
62 objArrayOop allocate(int length, TRAPS);
63 oop multi_allocate(int rank, jint* sizes, TRAPS);
65 // Copying
66 void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS);
68 // Compute protection domain
69 oop protection_domain() { return Klass::cast(bottom_klass())->protection_domain(); }
70 // Compute class loader
71 oop class_loader() const { return Klass::cast(bottom_klass())->class_loader(); }
73 private:
74 // Either oop or narrowOop depending on UseCompressedOops.
75 // must be called from within objArrayKlass.cpp
76 template <class T> void do_copy(arrayOop s, T* src, arrayOop d,
77 T* dst, int length, TRAPS);
78 protected:
79 // Returns the objArrayKlass for n'th dimension.
80 virtual klassOop array_klass_impl(bool or_null, int n, TRAPS);
82 // Returns the array class with this class as element type.
83 virtual klassOop array_klass_impl(bool or_null, TRAPS);
85 public:
86 // Casting from klassOop
87 static objArrayKlass* cast(klassOop k) {
88 assert(k->klass_part()->oop_is_objArray_slow(), "cast to objArrayKlass");
89 return (objArrayKlass*) k->klass_part();
90 }
92 // Sizing
93 static int header_size() { return oopDesc::header_size() + sizeof(objArrayKlass)/HeapWordSize; }
94 int object_size() const { return arrayKlass::object_size(header_size()); }
96 // Initialization (virtual from Klass)
97 void initialize(TRAPS);
99 // Garbage collection
100 void oop_follow_contents(oop obj);
101 inline void oop_follow_contents(oop obj, int index);
102 template <class T> inline void objarray_follow_contents(oop obj, int index);
104 int oop_adjust_pointers(oop obj);
106 // Parallel Scavenge and Parallel Old
107 PARALLEL_GC_DECLS
108 #ifndef SERIALGC
109 inline void oop_follow_contents(ParCompactionManager* cm, oop obj, int index);
110 template <class T> inline void
111 objarray_follow_contents(ParCompactionManager* cm, oop obj, int index);
112 #endif // !SERIALGC
114 // Iterators
115 int oop_oop_iterate(oop obj, OopClosure* blk) {
116 return oop_oop_iterate_v(obj, blk);
117 }
118 int oop_oop_iterate_m(oop obj, OopClosure* blk, MemRegion mr) {
119 return oop_oop_iterate_v_m(obj, blk, mr);
120 }
121 #define ObjArrayKlass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
122 int oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk); \
123 int oop_oop_iterate##nv_suffix##_m(oop obj, OopClosureType* blk, \
124 MemRegion mr); \
125 int oop_oop_iterate_range##nv_suffix(oop obj, OopClosureType* blk, \
126 int start, int end);
128 ALL_OOP_OOP_ITERATE_CLOSURES_1(ObjArrayKlass_OOP_OOP_ITERATE_DECL)
129 ALL_OOP_OOP_ITERATE_CLOSURES_2(ObjArrayKlass_OOP_OOP_ITERATE_DECL)
131 // JVM support
132 jint compute_modifier_flags(TRAPS) const;
134 private:
135 static klassOop array_klass_impl (objArrayKlassHandle this_oop, bool or_null, int n, TRAPS);
137 public:
138 // Printing
139 void oop_print_value_on(oop obj, outputStream* st);
140 #ifndef PRODUCT
141 void oop_print_on (oop obj, outputStream* st);
142 #endif //PRODUCT
144 // Verification
145 const char* internal_name() const;
146 void oop_verify_on(oop obj, outputStream* st);
147 void oop_verify_old_oop(oop obj, oop* p, bool allow_dirty);
148 void oop_verify_old_oop(oop obj, narrowOop* p, bool allow_dirty);
149 };
151 #endif // SHARE_VM_OOPS_OBJARRAYKLASS_HPP