jdk8-mips64-public/hotspot: src/share/vm/oops/instanceRefKlass.hpp@e1162778c1c8

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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     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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    25 #ifndef SHARE_VM_OOPS_INSTANCEREFKLASS_HPP

    26 #define SHARE_VM_OOPS_INSTANCEREFKLASS_HPP

    28 #include "oops/instanceKlass.hpp"

    30 // An instanceRefKlass is a specialized instanceKlass for Java

    31 // classes that are subclasses of java/lang/ref/Reference.

    32 //

    33 // These classes are used to implement soft/weak/final/phantom

    34 // references and finalization, and need special treatment by the

    35 // garbage collector.

    36 //

    37 // During GC discovered reference objects are added (chained) to one

    38 // of the four lists below, depending on the type of reference.

    39 // The linked occurs through the next field in class java/lang/ref/Reference.

    40 //

    41 // Afterwards, the discovered references are processed in decreasing

    42 // order of reachability. Reference objects eligible for notification

    43 // are linked to the static pending_list in class java/lang/ref/Reference,

    44 // and the pending list lock object in the same class is notified.

    47 class instanceRefKlass: public instanceKlass {

    48  public:

    49   // Type testing

    50   bool oop_is_instanceRef() const             { return true; }

    52   // Casting from klassOop

    53   static instanceRefKlass* cast(klassOop k) {

    54     assert(k->klass_part()->oop_is_instanceRef(), "cast to instanceRefKlass");

    55     return (instanceRefKlass*) k->klass_part();

    56   }

    58   // allocation

    59   DEFINE_ALLOCATE_PERMANENT(instanceRefKlass);

    61   // Garbage collection

    62   int  oop_adjust_pointers(oop obj);

    63   void oop_follow_contents(oop obj);

    65   // Parallel Scavenge and Parallel Old

    66   PARALLEL_GC_DECLS

    68   int oop_oop_iterate(oop obj, OopClosure* blk) {

    69     return oop_oop_iterate_v(obj, blk);

    70   }

    71   int oop_oop_iterate_m(oop obj, OopClosure* blk, MemRegion mr) {

    72     return oop_oop_iterate_v_m(obj, blk, mr);

    73   }

    75 #define InstanceRefKlass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix)                \

    76   int oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk);                         \

    77   int oop_oop_iterate##nv_suffix##_m(oop obj, OopClosureType* blk, MemRegion mr);

    79   ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceRefKlass_OOP_OOP_ITERATE_DECL)

    80   ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceRefKlass_OOP_OOP_ITERATE_DECL)

    82 #ifndef SERIALGC

    83 #define InstanceRefKlass_OOP_OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix)      \

    84   int oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* blk);

    86   ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceRefKlass_OOP_OOP_ITERATE_BACKWARDS_DECL)

    87   ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceRefKlass_OOP_OOP_ITERATE_BACKWARDS_DECL)

    88 #endif // !SERIALGC

    90   static void release_and_notify_pending_list_lock(BasicLock *pending_list_basic_lock);

    91   static void acquire_pending_list_lock(BasicLock *pending_list_basic_lock);

    92   static bool owns_pending_list_lock(JavaThread* thread);

    94   // Update non-static oop maps so 'referent', 'nextPending' and

    95   // 'discovered' will look like non-oops

    96   static void update_nonstatic_oop_maps(klassOop k);

    98  public:

    99   // Verification

   100   void oop_verify_on(oop obj, outputStream* st);

   101 };

   103 #endif // SHARE_VM_OOPS_INSTANCEREFKLASS_HPP

Mercurial > jdk8-mips64-public > hotspot / file revision

src/share/vm/oops/instanceRefKlass.hpp@e1162778c1c8

src/share/vm/oops/instanceRefKlass.hpp