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24 
25 #ifndef SHARE_VM_GC_SHARED_GENOOPCLOSURES_HPP
26 #define SHARE_VM_GC_SHARED_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 CardTableBarrierSet;
35 class DefNewGeneration;
36 class KlassRemSet;
37 
38 // Closure for iterating roots from a particular generation
39 // Note: all classes deriving from this MUST call this do_barrier
40 // method at the end of their own do_oop method!
41 // Note: no do_oop defined, this is an abstract class.
42 
43 class OopsInGenClosure : public OopIterateClosure {
44  private:
45   Generation*  _orig_gen;     // generation originally set in ctor
46   Generation*  _gen;          // generation being scanned
47 
48  protected:
49   // Some subtypes need access.
50   HeapWord*    _gen_boundary; // start of generation
51   CardTableRS* _rs;           // remembered set
52 
53   // For assertions
generation()54   Generation* generation() { return _gen; }
rs()55   CardTableRS* rs() { return _rs; }
56 
57   // Derived classes that modify oops so that they might be old-to-young
58   // pointers must call the method below.
59   template <class T> void do_barrier(T* p);
60 
61   // Version for use by closures that may be called in parallel code.
62   template <class T> void par_do_barrier(T* p);
63 
64  public:
OopsInGenClosure()65   OopsInGenClosure() : OopIterateClosure(NULL),
66     _orig_gen(NULL), _gen(NULL), _gen_boundary(NULL), _rs(NULL) {};
67 
68   OopsInGenClosure(Generation* gen);
69   void set_generation(Generation* gen);
70 
reset_generation()71   void reset_generation() { _gen = _orig_gen; }
72 
73   // Problem with static closures: must have _gen_boundary set at some point,
74   // but cannot do this until after the heap is initialized.
set_orig_generation(Generation * gen)75   void set_orig_generation(Generation* gen) {
76     _orig_gen = gen;
77     set_generation(gen);
78   }
79 
gen_boundary()80   HeapWord* gen_boundary() { return _gen_boundary; }
81 
82 };
83 
84 class BasicOopsInGenClosure: public OopsInGenClosure {
85  public:
BasicOopsInGenClosure()86   BasicOopsInGenClosure() : OopsInGenClosure() {}
87   BasicOopsInGenClosure(Generation* gen);
88 
do_metadata()89   virtual bool do_metadata() { return false; }
do_klass(Klass * k)90   virtual void do_klass(Klass* k) { ShouldNotReachHere(); }
do_cld(ClassLoaderData * cld)91   virtual void do_cld(ClassLoaderData* cld) { ShouldNotReachHere(); }
92 };
93 
94 // Super class for scan closures. It contains code to dirty scanned class loader data.
95 class OopsInClassLoaderDataOrGenClosure: public BasicOopsInGenClosure {
96   ClassLoaderData* _scanned_cld;
97  public:
OopsInClassLoaderDataOrGenClosure(Generation * g)98   OopsInClassLoaderDataOrGenClosure(Generation* g) : BasicOopsInGenClosure(g), _scanned_cld(NULL) {}
set_scanned_cld(ClassLoaderData * cld)99   void set_scanned_cld(ClassLoaderData* cld) {
100     assert(cld == NULL || _scanned_cld == NULL, "Must be");
101     _scanned_cld = cld;
102   }
is_scanning_a_cld()103   bool is_scanning_a_cld() { return _scanned_cld != NULL; }
104   void do_cld_barrier();
105 };
106 
107 #if INCLUDE_SERIALGC
108 
109 // Closure for scanning DefNewGeneration.
110 //
111 // This closure will perform barrier store calls for ALL
112 // pointers in scanned oops.
113 class ScanClosure: public OopsInClassLoaderDataOrGenClosure {
114  private:
115   DefNewGeneration* _g;
116   HeapWord*         _boundary;
117   bool              _gc_barrier;
118   template <class T> inline void do_oop_work(T* p);
119  public:
120   ScanClosure(DefNewGeneration* g, bool gc_barrier);
121   virtual void do_oop(oop* p);
122   virtual void do_oop(narrowOop* p);
123 };
124 
125 // Closure for scanning DefNewGeneration.
126 //
127 // This closure only performs barrier store calls on
128 // pointers into the DefNewGeneration. This is less
129 // precise, but faster, than a ScanClosure
130 class FastScanClosure: public OopsInClassLoaderDataOrGenClosure {
131  protected:
132   DefNewGeneration* _g;
133   HeapWord*         _boundary;
134   bool              _gc_barrier;
135   template <class T> inline void do_oop_work(T* p);
136  public:
137   FastScanClosure(DefNewGeneration* g, bool gc_barrier);
138   virtual void do_oop(oop* p);
139   virtual void do_oop(narrowOop* p);
140 };
141 
142 #endif // INCLUDE_SERIALGC
143 
144 class CLDScanClosure: public CLDClosure {
145   OopsInClassLoaderDataOrGenClosure*   _scavenge_closure;
146   // true if the the modified oops state should be saved.
147   bool                                 _accumulate_modified_oops;
148  public:
CLDScanClosure(OopsInClassLoaderDataOrGenClosure * scavenge_closure,bool accumulate_modified_oops)149   CLDScanClosure(OopsInClassLoaderDataOrGenClosure* scavenge_closure,
150                  bool accumulate_modified_oops) :
151        _scavenge_closure(scavenge_closure), _accumulate_modified_oops(accumulate_modified_oops) {}
152   void do_cld(ClassLoaderData* cld);
153 };
154 
155 class FilteringClosure: public OopIterateClosure {
156  private:
157   HeapWord*   _boundary;
158   OopIterateClosure* _cl;
159  protected:
160   template <class T> inline void do_oop_work(T* p);
161  public:
FilteringClosure(HeapWord * boundary,OopIterateClosure * cl)162   FilteringClosure(HeapWord* boundary, OopIterateClosure* cl) :
163     OopIterateClosure(cl->ref_discoverer()), _boundary(boundary),
164     _cl(cl) {}
165   virtual void do_oop(oop* p);
166   virtual void do_oop(narrowOop* p);
do_metadata()167   virtual bool do_metadata()            { assert(!_cl->do_metadata(), "assumption broken, must change to 'return _cl->do_metadata()'"); return false; }
do_klass(Klass *)168   virtual void do_klass(Klass*)         { ShouldNotReachHere(); }
do_cld(ClassLoaderData *)169   virtual void do_cld(ClassLoaderData*) { ShouldNotReachHere(); }
170 };
171 
172 #if INCLUDE_SERIALGC
173 
174 // Closure for scanning DefNewGeneration's weak references.
175 // NOTE: very much like ScanClosure but not derived from
176 //  OopsInGenClosure -- weak references are processed all
177 //  at once, with no notion of which generation they were in.
178 class ScanWeakRefClosure: public OopClosure {
179  protected:
180   DefNewGeneration* _g;
181   HeapWord*         _boundary;
182   template <class T> inline void do_oop_work(T* p);
183  public:
184   ScanWeakRefClosure(DefNewGeneration* g);
185   virtual void do_oop(oop* p);
186   virtual void do_oop(narrowOop* p);
187 };
188 
189 #endif // INCLUDE_SERIALGC
190 
191 #endif // SHARE_VM_GC_SHARED_GENOOPCLOSURES_HPP
192