src/share/vm/oops/typeArrayKlass.hpp

Thu, 07 Apr 2011 09:53:20 -0700

author
johnc
date
Thu, 07 Apr 2011 09:53:20 -0700
changeset 2781
e1162778c1c8
parent 2314
f95d63e2154a
child 3157
a92cdbac8b9e
permissions
-rw-r--r--

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_TYPEARRAYKLASS_HPP
    26 #define SHARE_VM_OOPS_TYPEARRAYKLASS_HPP
    28 #include "oops/arrayKlass.hpp"
    30 // A typeArrayKlass is the klass of a typeArray
    31 // It contains the type and size of the elements
    33 class typeArrayKlass : public arrayKlass {
    34   friend class VMStructs;
    35  private:
    36   jint _max_length;            // maximum number of elements allowed in an array
    37  public:
    38   // instance variables
    39   jint max_length()                     { return _max_length; }
    40   void set_max_length(jint m)           { _max_length = m;    }
    42   // testers
    43   bool oop_is_typeArray_slow() const    { return true; }
    45   // klass allocation
    46   DEFINE_ALLOCATE_PERMANENT(typeArrayKlass);
    47   static klassOop create_klass(BasicType type, int scale, const char* name_str,
    48                                TRAPS);
    49   static inline klassOop create_klass(BasicType type, int scale, TRAPS) {
    50     return create_klass(type, scale, external_name(type), CHECK_NULL);
    51   }
    53   int oop_size(oop obj) const;
    54   int klass_oop_size() const  { return object_size(); }
    56   bool compute_is_subtype_of(klassOop k);
    58   // Allocation
    59   typeArrayOop allocate(int length, TRAPS);
    60   typeArrayOop allocate_permanent(int length, TRAPS);  // used for class file structures
    61   oop multi_allocate(int rank, jint* sizes, TRAPS);
    63   // Copying
    64   void  copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS);
    66   // Iteration
    67   int oop_oop_iterate(oop obj, OopClosure* blk);
    68   int oop_oop_iterate_m(oop obj, OopClosure* blk, MemRegion mr);
    70   // Garbage collection
    71   void oop_follow_contents(oop obj);
    72   int  oop_adjust_pointers(oop obj);
    74   // Parallel Scavenge and Parallel Old
    75   PARALLEL_GC_DECLS
    77  protected:
    78   // Find n'th dimensional array
    79   virtual klassOop array_klass_impl(bool or_null, int n, TRAPS);
    81   // Returns the array class with this class as element type
    82   virtual klassOop array_klass_impl(bool or_null, TRAPS);
    84  public:
    85   // Casting from klassOop
    86   static typeArrayKlass* cast(klassOop k) {
    87     assert(k->klass_part()->oop_is_typeArray_slow(), "cast to typeArrayKlass");
    88     return (typeArrayKlass*) k->klass_part();
    89   }
    91   // Naming
    92   static const char* external_name(BasicType type);
    94   // Sizing
    95   static int header_size()  { return oopDesc::header_size() + sizeof(typeArrayKlass)/HeapWordSize; }
    96   int object_size() const   { return arrayKlass::object_size(header_size()); }
    98   // Initialization (virtual from Klass)
    99   void initialize(TRAPS);
   101  private:
   102    // Helpers
   103    static klassOop array_klass_impl(typeArrayKlassHandle h_this, bool or_null, int n, TRAPS);
   105 #ifndef PRODUCT
   106  public:
   107   // Printing
   108   void oop_print_on(oop obj, outputStream* st);
   109 #endif
   110  public:
   111   const char* internal_name() const;
   112 };
   114 #endif // SHARE_VM_OOPS_TYPEARRAYKLASS_HPP

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