duke@435: /*
mikael@6198:  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. 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:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
duke@435:  *
duke@435:  */
duke@435: 
stefank@2314: #ifndef SHARE_VM_MEMORY_ITERATOR_HPP
stefank@2314: #define SHARE_VM_MEMORY_ITERATOR_HPP
stefank@2314: 
stefank@2314: #include "memory/allocation.hpp"
stefank@2314: #include "memory/memRegion.hpp"
stefank@2314: #include "runtime/prefetch.hpp"
stefank@2314: #include "utilities/top.hpp"
stefank@2314: 
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;
coleenp@4037: class KlassClosure;
coleenp@4037: class ClassLoaderData;
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: 
coleenp@4037: // OopClosure is used for iterating through references to Java objects.
duke@435: 
ysr@777: class OopClosure : public Closure {
duke@435:  public:
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); }
coleenp@4037: };
duke@435: 
coleenp@4037: // ExtendedOopClosure adds extra code to be run during oop iterations.
coleenp@4037: // This is needed by the GC and is extracted to a separate type to not
coleenp@4037: // pollute the OopClosure interface.
coleenp@4037: class ExtendedOopClosure : public OopClosure {
coleenp@4037:  public:
coleenp@4037:   ReferenceProcessor* _ref_processor;
coleenp@4037:   ExtendedOopClosure(ReferenceProcessor* rp) : _ref_processor(rp) { }
coleenp@4037:   ExtendedOopClosure() : OopClosure(), _ref_processor(NULL) { }
jmasa@1370: 
coleenp@4037:   // If the do_metadata functions return "true",
coleenp@4037:   // we invoke the following when running oop_iterate():
coleenp@4037:   //
coleenp@4037:   // 1) do_klass on the header klass pointer.
coleenp@4037:   // 2) do_klass on the klass pointer in the mirrors.
coleenp@4037:   // 3) do_class_loader_data on the class loader data in class loaders.
coleenp@4037:   //
coleenp@4037:   // The virtual (without suffix) and the non-virtual (with _nv suffix) need
coleenp@4037:   // to be updated together, or else the devirtualization will break.
coleenp@4037:   //
coleenp@4037:   // Providing default implementations of the _nv functions unfortunately
coleenp@4037:   // removes the compile-time safeness, but reduces the clutter for the
stefank@6992:   // ExtendedOopClosures that don't need to walk the metadata.
stefank@6992:   // Currently, only CMS and G1 need these.
jmasa@1370: 
coleenp@4037:   virtual bool do_metadata() { return do_metadata_nv(); }
coleenp@4037:   bool do_metadata_v()       { return do_metadata(); }
coleenp@4037:   bool do_metadata_nv()      { return false; }
duke@435: 
coleenp@4037:   virtual void do_klass(Klass* k)   { do_klass_nv(k); }
coleenp@4037:   void do_klass_v(Klass* k)         { do_klass(k); }
coleenp@4037:   void do_klass_nv(Klass* k)        { ShouldNotReachHere(); }
ysr@1376: 
coleenp@4037:   virtual void do_class_loader_data(ClassLoaderData* cld) { ShouldNotReachHere(); }
duke@435: 
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; }
coleenp@4037: };
jmasa@1370: 
coleenp@4037: // Wrapper closure only used to implement oop_iterate_no_header().
coleenp@4037: class NoHeaderExtendedOopClosure : public ExtendedOopClosure {
coleenp@4037:   OopClosure* _wrapped_closure;
coleenp@4037:  public:
coleenp@4037:   NoHeaderExtendedOopClosure(OopClosure* cl) : _wrapped_closure(cl) {}
coleenp@4037:   // Warning: this calls the virtual version do_oop in the the wrapped closure.
coleenp@4037:   void do_oop_nv(oop* p)       { _wrapped_closure->do_oop(p); }
coleenp@4037:   void do_oop_nv(narrowOop* p) { _wrapped_closure->do_oop(p); }
coleenp@4037: 
coleenp@4037:   void do_oop(oop* p)          { assert(false, "Only the _nv versions should be used");
coleenp@4037:                                  _wrapped_closure->do_oop(p); }
coleenp@4037:   void do_oop(narrowOop* p)    { assert(false, "Only the _nv versions should be used");
coleenp@4037:                                  _wrapped_closure->do_oop(p);}
coleenp@4037: };
coleenp@4037: 
coleenp@4037: class KlassClosure : public Closure {
coleenp@4037:  public:
coleenp@4037:   virtual void do_klass(Klass* k) = 0;
duke@435: };
duke@435: 
stefank@6973: class CLDClosure : public Closure {
stefank@6973:  public:
stefank@6973:   virtual void do_cld(ClassLoaderData* cld) = 0;
stefank@6973: };
stefank@6973: 
stefank@4050: class KlassToOopClosure : public KlassClosure {
stefank@6982:   friend class MetadataAwareOopClosure;
stefank@6982:   friend class MetadataAwareOopsInGenClosure;
stefank@6982: 
stefank@4050:   OopClosure* _oop_closure;
stefank@6982: 
stefank@6982:   // Used when _oop_closure couldn't be set in an initialization list.
stefank@6982:   void initialize(OopClosure* oop_closure) {
stefank@6982:     assert(_oop_closure == NULL, "Should only be called once");
stefank@6982:     _oop_closure = oop_closure;
stefank@6982:   }
stefank@6982: 
stefank@6992:  public:
stefank@6982:   KlassToOopClosure(OopClosure* oop_closure = NULL) : _oop_closure(oop_closure) {}
stefank@6992: 
stefank@4050:   virtual void do_klass(Klass* k);
stefank@4050: };
stefank@4050: 
stefank@6973: class CLDToOopClosure : public CLDClosure {
stefank@6992:   OopClosure*       _oop_closure;
stefank@4298:   KlassToOopClosure _klass_closure;
stefank@6992:   bool              _must_claim_cld;
stefank@4298: 
stefank@4298:  public:
stefank@4298:   CLDToOopClosure(OopClosure* oop_closure, bool must_claim_cld = true) :
stefank@4298:       _oop_closure(oop_closure),
stefank@4298:       _klass_closure(oop_closure),
stefank@4298:       _must_claim_cld(must_claim_cld) {}
stefank@4298: 
stefank@4298:   void do_cld(ClassLoaderData* cld);
stefank@4298: };
stefank@4298: 
stefank@6992: class CLDToKlassAndOopClosure : public CLDClosure {
stefank@6992:   friend class SharedHeap;
stefank@6992:   friend class G1CollectedHeap;
stefank@6992:  protected:
stefank@6992:   OopClosure*   _oop_closure;
stefank@6992:   KlassClosure* _klass_closure;
stefank@6992:   bool          _must_claim_cld;
stefank@6992:  public:
stefank@6992:   CLDToKlassAndOopClosure(KlassClosure* klass_closure,
stefank@6992:                           OopClosure* oop_closure,
stefank@6992:                           bool must_claim_cld) :
stefank@6992:                               _oop_closure(oop_closure),
stefank@6992:                               _klass_closure(klass_closure),
stefank@6992:                               _must_claim_cld(must_claim_cld) {}
stefank@6992:   void do_cld(ClassLoaderData* cld);
stefank@6992: };
stefank@6992: 
stefank@6982: // The base class for all concurrent marking closures,
stefank@6982: // that participates in class unloading.
stefank@6982: // It's used to proxy through the metadata to the oops defined in them.
stefank@6982: class MetadataAwareOopClosure: public ExtendedOopClosure {
stefank@6982:   KlassToOopClosure _klass_closure;
stefank@6982: 
stefank@6982:  public:
stefank@6982:   MetadataAwareOopClosure() : ExtendedOopClosure() {
stefank@6982:     _klass_closure.initialize(this);
stefank@6982:   }
stefank@6982:   MetadataAwareOopClosure(ReferenceProcessor* rp) : ExtendedOopClosure(rp) {
stefank@6982:     _klass_closure.initialize(this);
stefank@6982:   }
stefank@6982: 
stefank@6982:   virtual bool do_metadata()    { return do_metadata_nv(); }
stefank@6982:   inline  bool do_metadata_nv() { return true; }
stefank@6982: 
stefank@6982:   virtual void do_klass(Klass* k);
stefank@6982:   void do_klass_nv(Klass* k);
stefank@6982: 
stefank@6982:   virtual void do_class_loader_data(ClassLoaderData* cld);
stefank@6982: };
stefank@6982: 
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: 
ehelin@5159: class BoolObjectClosure : public Closure {
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 {
coleenp@4037:   ExtendedOopClosure* _cl;
duke@435: public:
duke@435:   void do_object(oop obj);
coleenp@4037:   ObjectToOopClosure(ExtendedOopClosure* cl) : _cl(cl) {}
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: 
stefank@6992: // Applies an oop closure to all ref fields in code blobs
stefank@6992: // iterated over in an object iteration.
stefank@6992: class CodeBlobToOopClosure : public CodeBlobClosure {
stefank@6992:   OopClosure* _cl;
stefank@6992:   bool _fix_relocations;
stefank@6992:  protected:
stefank@6992:   void do_nmethod(nmethod* nm);
stefank@6992:  public:
stefank@6992:   CodeBlobToOopClosure(OopClosure* cl, bool fix_relocations) : _cl(cl), _fix_relocations(fix_relocations) {}
stefank@6992:   virtual void do_code_blob(CodeBlob* cb);
jrose@1424: 
stefank@6992:   const static bool FixRelocations = true;
stefank@6992: };
stefank@6992: 
stefank@6992: class MarkingCodeBlobClosure : public CodeBlobToOopClosure {
jrose@1424:  public:
stefank@6992:   MarkingCodeBlobClosure(OopClosure* cl, bool fix_relocations) : CodeBlobToOopClosure(cl, fix_relocations) {}
jrose@1424:   // Called for each code blob, but at most once per unique blob.
jrose@1424: 
jrose@1424:   virtual void do_code_blob(CodeBlob* 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: 
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: 
coleenp@4037: class SerializeClosure : public Closure {
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 void pointer pointed to by p.
duke@435:   virtual void do_ptr(void** 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: 
coleenp@2497: class SymbolClosure : public StackObj {
coleenp@2497:  public:
coleenp@2497:   virtual void do_symbol(Symbol**) = 0;
coleenp@2497: 
coleenp@2497:   // Clear LSB in symbol address; it can be set by CPSlot.
coleenp@2497:   static Symbol* load_symbol(Symbol** p) {
coleenp@2497:     return (Symbol*)(intptr_t(*p) & ~1);
coleenp@2497:   }
coleenp@2497: 
coleenp@2497:   // Store symbol, adjusting new pointer if the original pointer was adjusted
coleenp@2497:   // (symbol references in constant pool slots have their LSB set to 1).
coleenp@2497:   static void store_symbol(Symbol** p, Symbol* sym) {
coleenp@2497:     *p = (Symbol*)(intptr_t(sym) | (intptr_t(*p) & 1));
coleenp@2497:   }
coleenp@2497: };
coleenp@2497: 
stefank@6982: 
stefank@6982: // Helper defines for ExtendOopClosure
stefank@6982: 
stefank@6982: #define if_do_metadata_checked(closure, nv_suffix)       \
stefank@6982:   /* Make sure the non-virtual and the virtual versions match. */     \
stefank@6982:   assert(closure->do_metadata##nv_suffix() == closure->do_metadata(), \
stefank@6982:       "Inconsistency in do_metadata");                                \
stefank@6982:   if (closure->do_metadata##nv_suffix())
stefank@6982: 
stefank@6982: #define assert_should_ignore_metadata(closure, nv_suffix)                                  \
stefank@6982:   assert(!closure->do_metadata##nv_suffix(), "Code to handle metadata is not implemented")
stefank@6982: 
stefank@2314: #endif // SHARE_VM_MEMORY_ITERATOR_HPP