duke@435: /*
xdono@1383:  * Copyright 1997-2009 Sun Microsystems, Inc.  All Rights Reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
duke@435:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435:  * CA 95054 USA or visit www.sun.com if you need additional information or
duke@435:  * have any questions.
duke@435:  *
duke@435:  */
duke@435: 
duke@435: // The following classes are C++ `closures` for iterating over objects, roots and spaces
duke@435: 
jrose@1424: class CodeBlob;
jrose@1429: class nmethod;
duke@435: class ReferenceProcessor;
ysr@1376: class DataLayout;
duke@435: 
ysr@777: // Closure provides abortability.
ysr@777: 
ysr@777: class Closure : public StackObj {
ysr@777:  protected:
ysr@777:   bool _abort;
ysr@777:   void set_abort() { _abort = true; }
ysr@777:  public:
ysr@777:   Closure() : _abort(false) {}
ysr@777:   // A subtype can use this mechanism to indicate to some iterator mapping
ysr@777:   // functions that the iteration should cease.
ysr@777:   bool abort() { return _abort; }
ysr@777:   void clear_abort() { _abort = false; }
ysr@777: };
ysr@777: 
duke@435: // OopClosure is used for iterating through roots (oop*)
duke@435: 
ysr@777: class OopClosure : public Closure {
duke@435:  public:
duke@435:   ReferenceProcessor* _ref_processor;
duke@435:   OopClosure(ReferenceProcessor* rp) : _ref_processor(rp) { }
duke@435:   OopClosure() : _ref_processor(NULL) { }
duke@435:   virtual void do_oop(oop* o) = 0;
duke@435:   virtual void do_oop_v(oop* o) { do_oop(o); }
coleenp@548:   virtual void do_oop(narrowOop* o) = 0;
coleenp@548:   virtual void do_oop_v(narrowOop* o) { do_oop(o); }
duke@435: 
duke@435:   // In support of post-processing of weak links of KlassKlass objects;
duke@435:   // see KlassKlass::oop_oop_iterate().
jmasa@1370: 
jmasa@1370:   virtual const bool should_remember_klasses() const {
jmasa@1370:     assert(!must_remember_klasses(), "Should have overriden this method.");
jmasa@1370:     return false;
jmasa@1370:   }
jmasa@1370: 
duke@435:   virtual void remember_klass(Klass* k) { /* do nothing */ }
duke@435: 
ysr@1376:   // In support of post-processing of weak references in
ysr@1376:   // ProfileData (MethodDataOop) objects; see, for example,
ysr@1376:   // VirtualCallData::oop_iterate().
ysr@1376:   virtual const bool should_remember_mdo() const { return false; }
ysr@1376:   virtual void remember_mdo(DataLayout* v) { /* do nothing */ }
ysr@1376: 
duke@435:   // The methods below control how object iterations invoking this closure
duke@435:   // should be performed:
duke@435: 
duke@435:   // If "true", invoke on header klass field.
duke@435:   bool do_header() { return true; } // Note that this is non-virtual.
duke@435:   // Controls how prefetching is done for invocations of this closure.
duke@435:   Prefetch::style prefetch_style() { // Note that this is non-virtual.
duke@435:     return Prefetch::do_none;
duke@435:   }
ysr@777: 
ysr@777:   // True iff this closure may be safely applied more than once to an oop
ysr@777:   // location without an intervening "major reset" (like the end of a GC).
ysr@777:   virtual bool idempotent() { return false; }
ysr@777:   virtual bool apply_to_weak_ref_discovered_field() { return false; }
jmasa@1370: 
jmasa@1370: #ifdef ASSERT
jmasa@1370:   static bool _must_remember_klasses;
jmasa@1370:   static bool must_remember_klasses();
jmasa@1370:   static void set_must_remember_klasses(bool v);
jmasa@1370: #endif
duke@435: };
duke@435: 
duke@435: // ObjectClosure is used for iterating through an object space
duke@435: 
ysr@777: class ObjectClosure : public Closure {
duke@435:  public:
duke@435:   // Called for each object.
duke@435:   virtual void do_object(oop obj) = 0;
duke@435: };
duke@435: 
duke@435: 
duke@435: class BoolObjectClosure : public ObjectClosure {
duke@435:  public:
duke@435:   virtual bool do_object_b(oop obj) = 0;
duke@435: };
duke@435: 
duke@435: // Applies an oop closure to all ref fields in objects iterated over in an
duke@435: // object iteration.
duke@435: class ObjectToOopClosure: public ObjectClosure {
duke@435:   OopClosure* _cl;
duke@435: public:
duke@435:   void do_object(oop obj);
duke@435:   ObjectToOopClosure(OopClosure* cl) : _cl(cl) {}
duke@435: };
duke@435: 
duke@435: // A version of ObjectClosure with "memory" (see _previous_address below)
duke@435: class UpwardsObjectClosure: public BoolObjectClosure {
duke@435:   HeapWord* _previous_address;
duke@435:  public:
duke@435:   UpwardsObjectClosure() : _previous_address(NULL) { }
duke@435:   void set_previous(HeapWord* addr) { _previous_address = addr; }
duke@435:   HeapWord* previous()              { return _previous_address; }
duke@435:   // A return value of "true" can be used by the caller to decide
duke@435:   // if this object's end should *NOT* be recorded in
duke@435:   // _previous_address above.
duke@435:   virtual bool do_object_bm(oop obj, MemRegion mr) = 0;
duke@435: };
duke@435: 
duke@435: // A version of ObjectClosure that is expected to be robust
duke@435: // in the face of possibly uninitialized objects.
duke@435: class ObjectClosureCareful : public ObjectClosure {
duke@435:  public:
duke@435:   virtual size_t do_object_careful_m(oop p, MemRegion mr) = 0;
duke@435:   virtual size_t do_object_careful(oop p) = 0;
duke@435: };
duke@435: 
duke@435: // The following are used in CompactibleFreeListSpace and
duke@435: // ConcurrentMarkSweepGeneration.
duke@435: 
duke@435: // Blk closure (abstract class)
duke@435: class BlkClosure : public StackObj {
duke@435:  public:
duke@435:   virtual size_t do_blk(HeapWord* addr) = 0;
duke@435: };
duke@435: 
duke@435: // A version of BlkClosure that is expected to be robust
duke@435: // in the face of possibly uninitialized objects.
duke@435: class BlkClosureCareful : public BlkClosure {
duke@435:  public:
duke@435:   size_t do_blk(HeapWord* addr) {
duke@435:     guarantee(false, "call do_blk_careful instead");
duke@435:     return 0;
duke@435:   }
duke@435:   virtual size_t do_blk_careful(HeapWord* addr) = 0;
duke@435: };
duke@435: 
duke@435: // SpaceClosure is used for iterating over spaces
duke@435: 
duke@435: class Space;
duke@435: class CompactibleSpace;
duke@435: 
duke@435: class SpaceClosure : public StackObj {
duke@435:  public:
duke@435:   // Called for each space
duke@435:   virtual void do_space(Space* s) = 0;
duke@435: };
duke@435: 
duke@435: class CompactibleSpaceClosure : public StackObj {
duke@435:  public:
duke@435:   // Called for each compactible space
duke@435:   virtual void do_space(CompactibleSpace* s) = 0;
duke@435: };
duke@435: 
duke@435: 
jrose@1424: // CodeBlobClosure is used for iterating through code blobs
jrose@1424: // in the code cache or on thread stacks
jrose@1424: 
jrose@1424: class CodeBlobClosure : public Closure {
jrose@1424:  public:
jrose@1424:   // Called for each code blob.
jrose@1424:   virtual void do_code_blob(CodeBlob* cb) = 0;
jrose@1424: };
jrose@1424: 
jrose@1424: 
jrose@1424: class MarkingCodeBlobClosure : public CodeBlobClosure {
jrose@1424:  public:
jrose@1424:   // Called for each code blob, but at most once per unique blob.
jrose@1429:   virtual void do_newly_marked_nmethod(nmethod* nm) = 0;
jrose@1424: 
jrose@1424:   virtual void do_code_blob(CodeBlob* cb);
jrose@1424:     // = { if (!nmethod(cb)->test_set_oops_do_mark())  do_newly_marked_nmethod(cb); }
jrose@1424: 
jrose@1424:   class MarkScope : public StackObj {
jrose@1424:   protected:
jrose@1424:     bool _active;
jrose@1424:   public:
jrose@1424:     MarkScope(bool activate = true);
jrose@1424:       // = { if (active) nmethod::oops_do_marking_prologue(); }
jrose@1424:     ~MarkScope();
jrose@1424:       // = { if (active) nmethod::oops_do_marking_epilogue(); }
jrose@1424:   };
jrose@1424: };
jrose@1424: 
jrose@1424: 
jrose@1424: // Applies an oop closure to all ref fields in code blobs
jrose@1424: // iterated over in an object iteration.
jrose@1424: class CodeBlobToOopClosure: public MarkingCodeBlobClosure {
jrose@1424:   OopClosure* _cl;
jrose@1424:   bool _do_marking;
jrose@1424: public:
jrose@1429:   virtual void do_newly_marked_nmethod(nmethod* cb);
jrose@1424:     // = { cb->oops_do(_cl); }
jrose@1424:   virtual void do_code_blob(CodeBlob* cb);
jrose@1424:     // = { if (_do_marking)  super::do_code_blob(cb); else cb->oops_do(_cl); }
jrose@1424:   CodeBlobToOopClosure(OopClosure* cl, bool do_marking)
jrose@1424:     : _cl(cl), _do_marking(do_marking) {}
jrose@1424: };
jrose@1424: 
jrose@1424: 
duke@435: 
duke@435: // MonitorClosure is used for iterating over monitors in the monitors cache
duke@435: 
duke@435: class ObjectMonitor;
duke@435: 
duke@435: class MonitorClosure : public StackObj {
duke@435:  public:
duke@435:   // called for each monitor in cache
duke@435:   virtual void do_monitor(ObjectMonitor* m) = 0;
duke@435: };
duke@435: 
duke@435: // A closure that is applied without any arguments.
duke@435: class VoidClosure : public StackObj {
duke@435:  public:
duke@435:   // I would have liked to declare this a pure virtual, but that breaks
duke@435:   // in mysterious ways, for unknown reasons.
duke@435:   virtual void do_void();
duke@435: };
duke@435: 
duke@435: 
duke@435: // YieldClosure is intended for use by iteration loops
duke@435: // to incrementalize their work, allowing interleaving
duke@435: // of an interruptable task so as to allow other
duke@435: // threads to run (which may not otherwise be able to access
duke@435: // exclusive resources, for instance). Additionally, the
duke@435: // closure also allows for aborting an ongoing iteration
duke@435: // by means of checking the return value from the polling
duke@435: // call.
duke@435: class YieldClosure : public StackObj {
duke@435:   public:
duke@435:    virtual bool should_return() = 0;
duke@435: };
duke@435: 
duke@435: // Abstract closure for serializing data (read or write).
duke@435: 
duke@435: class SerializeOopClosure : public OopClosure {
duke@435: public:
duke@435:   // Return bool indicating whether closure implements read or write.
duke@435:   virtual bool reading() const = 0;
duke@435: 
duke@435:   // Read/write the int pointed to by i.
duke@435:   virtual void do_int(int* i) = 0;
duke@435: 
duke@435:   // Read/write the size_t pointed to by i.
duke@435:   virtual void do_size_t(size_t* i) = 0;
duke@435: 
duke@435:   // Read/write the void pointer pointed to by p.
duke@435:   virtual void do_ptr(void** p) = 0;
duke@435: 
duke@435:   // Read/write the HeapWord pointer pointed to be p.
duke@435:   virtual void do_ptr(HeapWord** p) = 0;
duke@435: 
duke@435:   // Read/write the region specified.
duke@435:   virtual void do_region(u_char* start, size_t size) = 0;
duke@435: 
duke@435:   // Check/write the tag.  If reading, then compare the tag against
duke@435:   // the passed in value and fail is they don't match.  This allows
duke@435:   // for verification that sections of the serialized data are of the
duke@435:   // correct length.
duke@435:   virtual void do_tag(int tag) = 0;
duke@435: };
jmasa@1370: 
jmasa@1370: #ifdef ASSERT
jmasa@1370: // This class is used to flag phases of a collection that
jmasa@1370: // can unload classes and which should override the
jmasa@1370: // should_remember_klasses() and remember_klass() of OopClosure.
jmasa@1370: // The _must_remember_klasses is set in the contructor and restored
jmasa@1370: // in the destructor.  _must_remember_klasses is checked in assertions
jmasa@1370: // in the OopClosure implementations of should_remember_klasses() and
jmasa@1370: // remember_klass() and the expectation is that the OopClosure
jmasa@1370: // implementation should not be in use if _must_remember_klasses is set.
jmasa@1370: // Instances of RememberKlassesChecker can be place in
jmasa@1370: // marking phases of collections which can do class unloading.
jmasa@1370: // RememberKlassesChecker can be passed "false" to turn off checking.
jmasa@1370: // It is used by CMS when CMS yields to a different collector.
jmasa@1370: class RememberKlassesChecker: StackObj {
jmasa@1370:  bool _state;
jmasa@1370:  bool _skip;
jmasa@1370:  public:
jmasa@1370:   RememberKlassesChecker(bool checking_on) : _state(false), _skip(false) {
jmasa@1370:     _skip = !(ClassUnloading && !UseConcMarkSweepGC ||
jmasa@1370:               CMSClassUnloadingEnabled && UseConcMarkSweepGC);
jmasa@1370:     if (_skip) {
jmasa@1370:       return;
jmasa@1370:     }
jmasa@1370:     _state = OopClosure::must_remember_klasses();
jmasa@1370:     OopClosure::set_must_remember_klasses(checking_on);
jmasa@1370:   }
jmasa@1370:   ~RememberKlassesChecker() {
jmasa@1370:     if (_skip) {
jmasa@1370:       return;
jmasa@1370:     }
jmasa@1370:     OopClosure::set_must_remember_klasses(_state);
jmasa@1370:   }
jmasa@1370: };
jmasa@1370: #endif  // ASSERT