jdk8-mips64-public/hotspot: src/share/vm/memory/iterator.hpp@2c6ef90f030a (annotated)

src/share/vm/memory/iterator.hpp@2c6ef90f030a (annotated)

src/share/vm/memory/iterator.hpp

Mon, 07 Jul 2014 10:12:40 +0200

author: stefank
date: Mon, 07 Jul 2014 10:12:40 +0200
changeset 6992: 2c6ef90f030a
parent 6982: 4c1b88a53c74
child 7535: 7ae4e26cb1e0
child 9661: 379a59bf685d
permissions: -rw-r--r--

8049421: G1 Class Unloading after completing a concurrent mark cycle
Reviewed-by: tschatzl, ehelin, brutisso, coleenp, roland, iveresov
Contributed-by: stefan.karlsson@oracle.com, mikael.gerdin@oracle.com

 /*
  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 #ifndef SHARE_VM_MEMORY_ITERATOR_HPP
 #define SHARE_VM_MEMORY_ITERATOR_HPP
 #include "memory/allocation.hpp"
 #include "memory/memRegion.hpp"
 #include "runtime/prefetch.hpp"
 #include "utilities/top.hpp"
 // The following classes are C++ `closures` for iterating over objects, roots and spaces
 class CodeBlob;
 class nmethod;
 class ReferenceProcessor;
 class DataLayout;
 class KlassClosure;
 class ClassLoaderData;
 // Closure provides abortability.
 class Closure : public StackObj {
  protected:
   bool _abort;
   void set_abort() { _abort = true; }
  public:
   Closure() : _abort(false) {}
   // A subtype can use this mechanism to indicate to some iterator mapping
   // functions that the iteration should cease.
   bool abort() { return _abort; }
   void clear_abort() { _abort = false; }
 };
 // OopClosure is used for iterating through references to Java objects.
 class OopClosure : public Closure {
  public:
   virtual void do_oop(oop* o) = 0;
   virtual void do_oop_v(oop* o) { do_oop(o); }
   virtual void do_oop(narrowOop* o) = 0;
   virtual void do_oop_v(narrowOop* o) { do_oop(o); }
 };
 // ExtendedOopClosure adds extra code to be run during oop iterations.
 // This is needed by the GC and is extracted to a separate type to not
 // pollute the OopClosure interface.
 class ExtendedOopClosure : public OopClosure {
  public:
   ReferenceProcessor* _ref_processor;
   ExtendedOopClosure(ReferenceProcessor* rp) : _ref_processor(rp) { }
   ExtendedOopClosure() : OopClosure(), _ref_processor(NULL) { }
   // If the do_metadata functions return "true",
   // we invoke the following when running oop_iterate():
   //
   // 1) do_klass on the header klass pointer.
   // 2) do_klass on the klass pointer in the mirrors.
   // 3) do_class_loader_data on the class loader data in class loaders.
   //
   // The virtual (without suffix) and the non-virtual (with _nv suffix) need
   // to be updated together, or else the devirtualization will break.
   //
   // Providing default implementations of the _nv functions unfortunately
   // removes the compile-time safeness, but reduces the clutter for the
   // ExtendedOopClosures that don't need to walk the metadata.
   // Currently, only CMS and G1 need these.
   virtual bool do_metadata() { return do_metadata_nv(); }
   bool do_metadata_v()       { return do_metadata(); }
   bool do_metadata_nv()      { return false; }
   virtual void do_klass(Klass* k)   { do_klass_nv(k); }
   void do_klass_v(Klass* k)         { do_klass(k); }
   void do_klass_nv(Klass* k)        { ShouldNotReachHere(); }
   virtual void do_class_loader_data(ClassLoaderData* cld) { ShouldNotReachHere(); }
   // Controls how prefetching is done for invocations of this closure.
   Prefetch::style prefetch_style() { // Note that this is non-virtual.
     return Prefetch::do_none;
   }
   // True iff this closure may be safely applied more than once to an oop
   // location without an intervening "major reset" (like the end of a GC).
   virtual bool idempotent() { return false; }
   virtual bool apply_to_weak_ref_discovered_field() { return false; }
 };
 // Wrapper closure only used to implement oop_iterate_no_header().
 class NoHeaderExtendedOopClosure : public ExtendedOopClosure {
   OopClosure* _wrapped_closure;
  public:
   NoHeaderExtendedOopClosure(OopClosure* cl) : _wrapped_closure(cl) {}
   // Warning: this calls the virtual version do_oop in the the wrapped closure.
   void do_oop_nv(oop* p)       { _wrapped_closure->do_oop(p); }
   void do_oop_nv(narrowOop* p) { _wrapped_closure->do_oop(p); }
   void do_oop(oop* p)          { assert(false, "Only the _nv versions should be used");
                                  _wrapped_closure->do_oop(p); }
   void do_oop(narrowOop* p)    { assert(false, "Only the _nv versions should be used");
                                  _wrapped_closure->do_oop(p);}
 };
 class KlassClosure : public Closure {
  public:
   virtual void do_klass(Klass* k) = 0;
 };
 class CLDClosure : public Closure {
  public:
   virtual void do_cld(ClassLoaderData* cld) = 0;
 };
 class KlassToOopClosure : public KlassClosure {
   friend class MetadataAwareOopClosure;
   friend class MetadataAwareOopsInGenClosure;
   OopClosure* _oop_closure;
   // Used when _oop_closure couldn't be set in an initialization list.
   void initialize(OopClosure* oop_closure) {
     assert(_oop_closure == NULL, "Should only be called once");
     _oop_closure = oop_closure;
   }
  public:
   KlassToOopClosure(OopClosure* oop_closure = NULL) : _oop_closure(oop_closure) {}
   virtual void do_klass(Klass* k);
 };
 class CLDToOopClosure : public CLDClosure {
   OopClosure*       _oop_closure;
   KlassToOopClosure _klass_closure;
   bool              _must_claim_cld;
  public:
   CLDToOopClosure(OopClosure* oop_closure, bool must_claim_cld = true) :
       _oop_closure(oop_closure),
       _klass_closure(oop_closure),
       _must_claim_cld(must_claim_cld) {}
   void do_cld(ClassLoaderData* cld);
 };
 class CLDToKlassAndOopClosure : public CLDClosure {
   friend class SharedHeap;
   friend class G1CollectedHeap;
  protected:
   OopClosure*   _oop_closure;
   KlassClosure* _klass_closure;
   bool          _must_claim_cld;
  public:
   CLDToKlassAndOopClosure(KlassClosure* klass_closure,
                           OopClosure* oop_closure,
                           bool must_claim_cld) :
                               _oop_closure(oop_closure),
                               _klass_closure(klass_closure),
                               _must_claim_cld(must_claim_cld) {}
   void do_cld(ClassLoaderData* cld);
 };
 // The base class for all concurrent marking closures,
 // that participates in class unloading.
 // It's used to proxy through the metadata to the oops defined in them.
 class MetadataAwareOopClosure: public ExtendedOopClosure {
   KlassToOopClosure _klass_closure;
  public:
   MetadataAwareOopClosure() : ExtendedOopClosure() {
     _klass_closure.initialize(this);
   }
   MetadataAwareOopClosure(ReferenceProcessor* rp) : ExtendedOopClosure(rp) {
     _klass_closure.initialize(this);
   }
   virtual bool do_metadata()    { return do_metadata_nv(); }
   inline  bool do_metadata_nv() { return true; }
   virtual void do_klass(Klass* k);
   void do_klass_nv(Klass* k);
   virtual void do_class_loader_data(ClassLoaderData* cld);
 };
 // ObjectClosure is used for iterating through an object space
 class ObjectClosure : public Closure {
  public:
   // Called for each object.
   virtual void do_object(oop obj) = 0;
 };
 class BoolObjectClosure : public Closure {
  public:
   virtual bool do_object_b(oop obj) = 0;
 };
 // Applies an oop closure to all ref fields in objects iterated over in an
 // object iteration.
 class ObjectToOopClosure: public ObjectClosure {
   ExtendedOopClosure* _cl;
 public:
   void do_object(oop obj);
   ObjectToOopClosure(ExtendedOopClosure* cl) : _cl(cl) {}
 };
 // A version of ObjectClosure that is expected to be robust
 // in the face of possibly uninitialized objects.
 class ObjectClosureCareful : public ObjectClosure {
  public:
   virtual size_t do_object_careful_m(oop p, MemRegion mr) = 0;
   virtual size_t do_object_careful(oop p) = 0;
 };
 // The following are used in CompactibleFreeListSpace and
 // ConcurrentMarkSweepGeneration.
 // Blk closure (abstract class)
 class BlkClosure : public StackObj {
  public:
   virtual size_t do_blk(HeapWord* addr) = 0;
 };
 // A version of BlkClosure that is expected to be robust
 // in the face of possibly uninitialized objects.
 class BlkClosureCareful : public BlkClosure {
  public:
   size_t do_blk(HeapWord* addr) {
     guarantee(false, "call do_blk_careful instead");
     return 0;
   }
   virtual size_t do_blk_careful(HeapWord* addr) = 0;
 };
 // SpaceClosure is used for iterating over spaces
 class Space;
 class CompactibleSpace;
 class SpaceClosure : public StackObj {
  public:
   // Called for each space
   virtual void do_space(Space* s) = 0;
 };
 class CompactibleSpaceClosure : public StackObj {
  public:
   // Called for each compactible space
   virtual void do_space(CompactibleSpace* s) = 0;
 };
 // CodeBlobClosure is used for iterating through code blobs
 // in the code cache or on thread stacks
 class CodeBlobClosure : public Closure {
  public:
   // Called for each code blob.
   virtual void do_code_blob(CodeBlob* cb) = 0;
 };
 // Applies an oop closure to all ref fields in code blobs
 // iterated over in an object iteration.
 class CodeBlobToOopClosure : public CodeBlobClosure {
   OopClosure* _cl;
   bool _fix_relocations;
  protected:
   void do_nmethod(nmethod* nm);
  public:
   CodeBlobToOopClosure(OopClosure* cl, bool fix_relocations) : _cl(cl), _fix_relocations(fix_relocations) {}
   virtual void do_code_blob(CodeBlob* cb);
   const static bool FixRelocations = true;
 };
 class MarkingCodeBlobClosure : public CodeBlobToOopClosure {
  public:
   MarkingCodeBlobClosure(OopClosure* cl, bool fix_relocations) : CodeBlobToOopClosure(cl, fix_relocations) {}
   // Called for each code blob, but at most once per unique blob.
   virtual void do_code_blob(CodeBlob* cb);
   class MarkScope : public StackObj {
   protected:
     bool _active;
   public:
     MarkScope(bool activate = true);
       // = { if (active) nmethod::oops_do_marking_prologue(); }
     ~MarkScope();
       // = { if (active) nmethod::oops_do_marking_epilogue(); }
   };
 };
 // MonitorClosure is used for iterating over monitors in the monitors cache
 class ObjectMonitor;
 class MonitorClosure : public StackObj {
  public:
   // called for each monitor in cache
   virtual void do_monitor(ObjectMonitor* m) = 0;
 };
 // A closure that is applied without any arguments.
 class VoidClosure : public StackObj {
  public:
   // I would have liked to declare this a pure virtual, but that breaks
   // in mysterious ways, for unknown reasons.
   virtual void do_void();
 };
 // YieldClosure is intended for use by iteration loops
 // to incrementalize their work, allowing interleaving
 // of an interruptable task so as to allow other
 // threads to run (which may not otherwise be able to access
 // exclusive resources, for instance). Additionally, the
 // closure also allows for aborting an ongoing iteration
 // by means of checking the return value from the polling
 // call.
 class YieldClosure : public StackObj {
   public:
    virtual bool should_return() = 0;
 };
 // Abstract closure for serializing data (read or write).
 class SerializeClosure : public Closure {
 public:
   // Return bool indicating whether closure implements read or write.
   virtual bool reading() const = 0;
   // Read/write the void pointer pointed to by p.
   virtual void do_ptr(void** p) = 0;
   // Read/write the region specified.
   virtual void do_region(u_char* start, size_t size) = 0;
   // Check/write the tag.  If reading, then compare the tag against
   // the passed in value and fail is they don't match.  This allows
   // for verification that sections of the serialized data are of the
   // correct length.
   virtual void do_tag(int tag) = 0;
 };
 class SymbolClosure : public StackObj {
  public:
   virtual void do_symbol(Symbol**) = 0;
   // Clear LSB in symbol address; it can be set by CPSlot.
   static Symbol* load_symbol(Symbol** p) {
     return (Symbol*)(intptr_t(*p) & ~1);
   }
   // Store symbol, adjusting new pointer if the original pointer was adjusted
   // (symbol references in constant pool slots have their LSB set to 1).
   static void store_symbol(Symbol** p, Symbol* sym) {
     *p = (Symbol*)(intptr_t(sym) | (intptr_t(*p) & 1));
   }
 };
 // Helper defines for ExtendOopClosure
 #define if_do_metadata_checked(closure, nv_suffix)       \
   /* Make sure the non-virtual and the virtual versions match. */     \
   assert(closure->do_metadata##nv_suffix() == closure->do_metadata(), \
       "Inconsistency in do_metadata");                                \
   if (closure->do_metadata##nv_suffix())
 #define assert_should_ignore_metadata(closure, nv_suffix)                                  \
   assert(!closure->do_metadata##nv_suffix(), "Code to handle metadata is not implemented")
 #endif // SHARE_VM_MEMORY_ITERATOR_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/memory/iterator.hpp@2c6ef90f030a (annotated)

src/share/vm/memory/iterator.hpp