1 /*
   2  * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
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  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
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  24 
  25 #ifndef SHARE_VM_MEMORY_GENOOPCLOSURES_HPP
  26 #define SHARE_VM_MEMORY_GENOOPCLOSURES_HPP
  27 
  28 #include "memory/iterator.hpp"
  29 #include "oops/oop.hpp"
  30 
  31 class Generation;
  32 class HeapWord;
  33 class CardTableRS;
  34 class CardTableModRefBS;
  35 class DefNewGeneration;
  36 class KlassRemSet;
  37 
  38 template<class E, MEMFLAGS F, unsigned int N> class GenericTaskQueue;
  39 typedef GenericTaskQueue<oop, mtGC, TASKQUEUE_SIZE> OopTaskQueue;
  40 template<class T, MEMFLAGS F> class GenericTaskQueueSet;
  41 typedef GenericTaskQueueSet<OopTaskQueue, mtGC> OopTaskQueueSet;
  42 
  43 // Closure for iterating roots from a particular generation
  44 // Note: all classes deriving from this MUST call this do_barrier
  45 // method at the end of their own do_oop method!
  46 // Note: no do_oop defined, this is an abstract class.
  47 
  48 class OopsInGenClosure : public ExtendedOopClosure {
  49  private:
  50   Generation*  _orig_gen;     // generation originally set in ctor
  51   Generation*  _gen;          // generation being scanned
  52 
  53  protected:
  54   // Some subtypes need access.
  55   HeapWord*    _gen_boundary; // start of generation
  56   CardTableRS* _rs;           // remembered set
  57 
  58   // For assertions
  59   Generation* generation() { return _gen; }
  60   CardTableRS* rs() { return _rs; }
  61 
  62   // Derived classes that modify oops so that they might be old-to-young
  63   // pointers must call the method below.
  64   template <class T> void do_barrier(T* p);
  65 
  66   // Version for use by closures that may be called in parallel code.
  67   template <class T> void par_do_barrier(T* p);
  68 
  69  public:
  70   OopsInGenClosure() : ExtendedOopClosure(NULL),
  71     _orig_gen(NULL), _gen(NULL), _gen_boundary(NULL), _rs(NULL) {};
  72 
  73   OopsInGenClosure(Generation* gen);
  74   void set_generation(Generation* gen);
  75 
  76   void reset_generation() { _gen = _orig_gen; }
  77 
  78   // Problem with static closures: must have _gen_boundary set at some point,
  79   // but cannot do this until after the heap is initialized.
  80   void set_orig_generation(Generation* gen) {
  81     _orig_gen = gen;
  82     set_generation(gen);
  83   }
  84 
  85   HeapWord* gen_boundary() { return _gen_boundary; }
  86 
  87 };
  88 
  89 // Super class for scan closures. It contains code to dirty scanned Klasses.
  90 class OopsInKlassOrGenClosure: public OopsInGenClosure {
  91   Klass* _scanned_klass;
  92  public:
  93   OopsInKlassOrGenClosure(Generation* g) : OopsInGenClosure(g), _scanned_klass(NULL) {}
  94   void set_scanned_klass(Klass* k) {
  95     assert(k == NULL || _scanned_klass == NULL, "Must be");
  96     _scanned_klass = k;
  97   }
  98   bool is_scanning_a_klass() { return _scanned_klass != NULL; }
  99   void do_klass_barrier();
 100 };
 101 
 102 // Closure for scanning DefNewGeneration.
 103 //
 104 // This closure will perform barrier store calls for ALL
 105 // pointers in scanned oops.
 106 class ScanClosure: public OopsInKlassOrGenClosure {
 107  protected:
 108   DefNewGeneration* _g;
 109   HeapWord*         _boundary;
 110   bool              _gc_barrier;
 111   template <class T> inline void do_oop_work(T* p);
 112  public:
 113   ScanClosure(DefNewGeneration* g, bool gc_barrier);
 114   virtual void do_oop(oop* p);
 115   virtual void do_oop(narrowOop* p);
 116   inline void do_oop_nv(oop* p);
 117   inline void do_oop_nv(narrowOop* p);
 118 };
 119 
 120 // Closure for scanning DefNewGeneration.
 121 //
 122 // This closure only performs barrier store calls on
 123 // pointers into the DefNewGeneration. This is less
 124 // precise, but faster, than a ScanClosure
 125 class FastScanClosure: public OopsInKlassOrGenClosure {
 126  protected:
 127   DefNewGeneration* _g;
 128   HeapWord*         _boundary;
 129   bool              _gc_barrier;
 130   template <class T> inline void do_oop_work(T* p);
 131  public:
 132   FastScanClosure(DefNewGeneration* g, bool gc_barrier);
 133   virtual void do_oop(oop* p);
 134   virtual void do_oop(narrowOop* p);
 135   inline void do_oop_nv(oop* p);
 136   inline void do_oop_nv(narrowOop* p);
 137 };
 138 
 139 class KlassScanClosure: public KlassClosure {
 140   OopsInKlassOrGenClosure* _scavenge_closure;
 141   // true if the the modified oops state should be saved.
 142   bool                     _accumulate_modified_oops;
 143  public:
 144   KlassScanClosure(OopsInKlassOrGenClosure* scavenge_closure,
 145                    KlassRemSet* klass_rem_set_policy);
 146   void do_klass(Klass* k);
 147 };
 148 
 149 class FilteringClosure: public ExtendedOopClosure {
 150  private:
 151   HeapWord*   _boundary;
 152   ExtendedOopClosure* _cl;
 153  protected:
 154   template <class T> inline void do_oop_work(T* p) {
 155     T heap_oop = oopDesc::load_heap_oop(p);
 156     if (!oopDesc::is_null(heap_oop)) {
 157       oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
 158       if ((HeapWord*)obj < _boundary) {
 159         _cl->do_oop(p);
 160       }
 161     }
 162   }
 163  public:
 164   FilteringClosure(HeapWord* boundary, ExtendedOopClosure* cl) :
 165     ExtendedOopClosure(cl->_ref_processor), _boundary(boundary),
 166     _cl(cl) {}
 167   virtual void do_oop(oop* p);
 168   virtual void do_oop(narrowOop* p);
 169   inline void do_oop_nv(oop* p)       { FilteringClosure::do_oop_work(p); }
 170   inline void do_oop_nv(narrowOop* p) { FilteringClosure::do_oop_work(p); }
 171   virtual bool do_metadata()          { return do_metadata_nv(); }
 172   inline bool do_metadata_nv()        { assert(!_cl->do_metadata(), "assumption broken, must change to 'return _cl->do_metadata()'"); return false; }
 173 };
 174 
 175 // Closure for scanning DefNewGeneration's weak references.
 176 // NOTE: very much like ScanClosure but not derived from
 177 //  OopsInGenClosure -- weak references are processed all
 178 //  at once, with no notion of which generation they were in.
 179 class ScanWeakRefClosure: public OopClosure {
 180  protected:
 181   DefNewGeneration* _g;
 182   HeapWord*         _boundary;
 183   template <class T> inline void do_oop_work(T* p);
 184  public:
 185   ScanWeakRefClosure(DefNewGeneration* g);
 186   virtual void do_oop(oop* p);
 187   virtual void do_oop(narrowOop* p);
 188   inline void do_oop_nv(oop* p);
 189   inline void do_oop_nv(narrowOop* p);
 190 };
 191 
 192 class VerifyOopClosure: public OopClosure {
 193  protected:
 194   template <class T> inline void do_oop_work(T* p) {
 195     oop obj = oopDesc::load_decode_heap_oop(p);
 196     guarantee(obj->is_oop_or_null(), err_msg("invalid oop: " INTPTR_FORMAT, p2i((oopDesc*) obj)));
 197   }
 198  public:
 199   virtual void do_oop(oop* p);
 200   virtual void do_oop(narrowOop* p);
 201   static VerifyOopClosure verify_oop;
 202 };
 203 
 204 #endif // SHARE_VM_MEMORY_GENOOPCLOSURES_HPP