src/share/vm/gc_implementation/g1/g1OopClosures.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 2962
ae5b2f1dcf12
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

     1 /*
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     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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     6  * under the terms of the GNU General Public License version 2 only, as
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    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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    12  * version 2 for more details (a copy is included in the LICENSE file that
    13  * accompanied this code).
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    25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1OOPCLOSURES_HPP
    26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1OOPCLOSURES_HPP
    28 class HeapRegion;
    29 class G1CollectedHeap;
    30 class G1RemSet;
    31 class ConcurrentMark;
    32 class DirtyCardToOopClosure;
    33 class CMBitMap;
    34 class CMMarkStack;
    35 class G1ParScanThreadState;
    37 // A class that scans oops in a given heap region (much as OopsInGenClosure
    38 // scans oops in a generation.)
    39 class OopsInHeapRegionClosure: public OopsInGenClosure {
    40 protected:
    41   HeapRegion* _from;
    42 public:
    43   virtual void set_region(HeapRegion* from) { _from = from; }
    44 };
    46 class G1ParClosureSuper : public OopsInHeapRegionClosure {
    47 protected:
    48   G1CollectedHeap* _g1;
    49   G1RemSet* _g1_rem;
    50   ConcurrentMark* _cm;
    51   G1ParScanThreadState* _par_scan_state;
    52 public:
    53   G1ParClosureSuper(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state);
    54   bool apply_to_weak_ref_discovered_field() { return true; }
    55 };
    57 class G1ParPushHeapRSClosure : public G1ParClosureSuper {
    58 public:
    59   G1ParPushHeapRSClosure(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state) :
    60     G1ParClosureSuper(g1, par_scan_state) { }
    61   template <class T> void do_oop_nv(T* p);
    62   virtual void do_oop(oop* p)          { do_oop_nv(p); }
    63   virtual void do_oop(narrowOop* p)    { do_oop_nv(p); }
    64 };
    66 class G1ParScanClosure : public G1ParClosureSuper {
    67 public:
    68   G1ParScanClosure(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state) :
    69     G1ParClosureSuper(g1, par_scan_state) { }
    70   template <class T> void do_oop_nv(T* p);
    71   virtual void do_oop(oop* p)          { do_oop_nv(p); }
    72   virtual void do_oop(narrowOop* p)    { do_oop_nv(p); }
    73 };
    75 #define G1_PARTIAL_ARRAY_MASK 0x2
    77 template <class T> inline bool has_partial_array_mask(T* ref) {
    78   return ((uintptr_t)ref & G1_PARTIAL_ARRAY_MASK) == G1_PARTIAL_ARRAY_MASK;
    79 }
    81 template <class T> inline T* set_partial_array_mask(T obj) {
    82   assert(((uintptr_t)obj & G1_PARTIAL_ARRAY_MASK) == 0, "Information loss!");
    83   return (T*) ((uintptr_t)obj | G1_PARTIAL_ARRAY_MASK);
    84 }
    86 template <class T> inline oop clear_partial_array_mask(T* ref) {
    87   return oop((intptr_t)ref & ~G1_PARTIAL_ARRAY_MASK);
    88 }
    90 class G1ParScanPartialArrayClosure : public G1ParClosureSuper {
    91   G1ParScanClosure _scanner;
    92 public:
    93   G1ParScanPartialArrayClosure(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state) :
    94     G1ParClosureSuper(g1, par_scan_state), _scanner(g1, par_scan_state) { }
    95   template <class T> void do_oop_nv(T* p);
    96   virtual void do_oop(oop* p)       { do_oop_nv(p); }
    97   virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
    98 };
   101 class G1ParCopyHelper : public G1ParClosureSuper {
   102   G1ParScanClosure *_scanner;
   103 protected:
   104   template <class T> void mark_forwardee(T* p);
   105   oop copy_to_survivor_space(oop obj);
   106 public:
   107   G1ParCopyHelper(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state,
   108                   G1ParScanClosure *scanner) :
   109     G1ParClosureSuper(g1, par_scan_state), _scanner(scanner) { }
   110 };
   112 template<bool do_gen_barrier, G1Barrier barrier,
   113          bool do_mark_forwardee>
   114 class G1ParCopyClosure : public G1ParCopyHelper {
   115   G1ParScanClosure _scanner;
   116   template <class T> void do_oop_work(T* p);
   117 public:
   118   G1ParCopyClosure(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state) :
   119     _scanner(g1, par_scan_state), G1ParCopyHelper(g1, par_scan_state, &_scanner) { }
   120   template <class T> void do_oop_nv(T* p) {
   121     do_oop_work(p);
   122     if (do_mark_forwardee)
   123       mark_forwardee(p);
   124   }
   125   virtual void do_oop(oop* p)       { do_oop_nv(p); }
   126   virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
   127 };
   129 typedef G1ParCopyClosure<false, G1BarrierNone, false> G1ParScanExtRootClosure;
   130 typedef G1ParCopyClosure<true,  G1BarrierNone, false> G1ParScanPermClosure;
   131 typedef G1ParCopyClosure<false, G1BarrierRS,   false> G1ParScanHeapRSClosure;
   132 typedef G1ParCopyClosure<false, G1BarrierNone, true> G1ParScanAndMarkExtRootClosure;
   133 typedef G1ParCopyClosure<true,  G1BarrierNone, true> G1ParScanAndMarkPermClosure;
   134 typedef G1ParCopyClosure<false, G1BarrierRS,   true> G1ParScanAndMarkHeapRSClosure;
   136 // This is the only case when we set skip_cset_test. Basically, this
   137 // closure is (should?) only be called directly while we're draining
   138 // the overflow and task queues. In that case we know that the
   139 // reference in question points into the collection set, otherwise we
   140 // would not have pushed it on the queue. The following is defined in
   141 // g1_specialized_oop_closures.hpp.
   142 // typedef G1ParCopyClosure<false, G1BarrierEvac, false, true> G1ParScanHeapEvacClosure;
   143 // We need a separate closure to handle references during evacuation
   144 // failure processing, as we cannot asume that the reference already
   145 // points into the collection set (like G1ParScanHeapEvacClosure does).
   146 typedef G1ParCopyClosure<false, G1BarrierEvac, false> G1ParScanHeapEvacFailureClosure;
   148 class FilterIntoCSClosure: public OopClosure {
   149   G1CollectedHeap* _g1;
   150   OopClosure* _oc;
   151   DirtyCardToOopClosure* _dcto_cl;
   152 public:
   153   FilterIntoCSClosure(  DirtyCardToOopClosure* dcto_cl,
   154                         G1CollectedHeap* g1, OopClosure* oc) :
   155     _dcto_cl(dcto_cl), _g1(g1), _oc(oc)
   156   {}
   157   template <class T> void do_oop_nv(T* p);
   158   virtual void do_oop(oop* p)        { do_oop_nv(p); }
   159   virtual void do_oop(narrowOop* p)  { do_oop_nv(p); }
   160   bool apply_to_weak_ref_discovered_field() { return true; }
   161   bool do_header() { return false; }
   162 };
   164 class FilterInHeapRegionAndIntoCSClosure : public OopsInHeapRegionClosure {
   165   G1CollectedHeap* _g1;
   166   OopsInHeapRegionClosure* _oc;
   167 public:
   168   FilterInHeapRegionAndIntoCSClosure(G1CollectedHeap* g1,
   169                                      OopsInHeapRegionClosure* oc) :
   170     _g1(g1), _oc(oc)
   171   {}
   172   template <class T> void do_oop_nv(T* p);
   173   virtual void do_oop(oop* p) { do_oop_nv(p); }
   174   virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
   175   bool apply_to_weak_ref_discovered_field() { return true; }
   176   bool do_header() { return false; }
   177   void set_region(HeapRegion* from) {
   178     _oc->set_region(from);
   179   }
   180 };
   182 class FilterAndMarkInHeapRegionAndIntoCSClosure : public OopsInHeapRegionClosure {
   183   G1CollectedHeap* _g1;
   184   ConcurrentMark* _cm;
   185   OopsInHeapRegionClosure* _oc;
   186 public:
   187   FilterAndMarkInHeapRegionAndIntoCSClosure(G1CollectedHeap* g1,
   188                                             OopsInHeapRegionClosure* oc,
   189                                             ConcurrentMark* cm)
   190   : _g1(g1), _oc(oc), _cm(cm) { }
   192   template <class T> void do_oop_nv(T* p);
   193   virtual void do_oop(oop* p) { do_oop_nv(p); }
   194   virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
   195   bool apply_to_weak_ref_discovered_field() { return true; }
   196   bool do_header() { return false; }
   197   void set_region(HeapRegion* from) {
   198     _oc->set_region(from);
   199   }
   200 };
   202 class FilterOutOfRegionClosure: public OopClosure {
   203   HeapWord* _r_bottom;
   204   HeapWord* _r_end;
   205   OopClosure* _oc;
   206   int _out_of_region;
   207 public:
   208   FilterOutOfRegionClosure(HeapRegion* r, OopClosure* oc);
   209   template <class T> void do_oop_nv(T* p);
   210   virtual void do_oop(oop* p) { do_oop_nv(p); }
   211   virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
   212   bool apply_to_weak_ref_discovered_field() { return true; }
   213   bool do_header() { return false; }
   214   int out_of_region() { return _out_of_region; }
   215 };
   217 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1OOPCLOSURES_HPP

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