aoqi@0: /*
aoqi@0:  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  *
aoqi@0:  */
aoqi@0: 
aoqi@0: #ifndef SHARE_VM_MEMORY_ITERATOR_HPP
aoqi@0: #define SHARE_VM_MEMORY_ITERATOR_HPP
aoqi@0: 
aoqi@0: #include "memory/allocation.hpp"
aoqi@0: #include "memory/memRegion.hpp"
aoqi@0: #include "runtime/prefetch.hpp"
aoqi@0: #include "utilities/top.hpp"
aoqi@0: 
aoqi@0: // The following classes are C++ `closures` for iterating over objects, roots and spaces
aoqi@0: 
aoqi@0: class CodeBlob;
aoqi@0: class nmethod;
aoqi@0: class ReferenceProcessor;
aoqi@0: class DataLayout;
aoqi@0: class KlassClosure;
aoqi@0: class ClassLoaderData;
aoqi@0: 
aoqi@0: // Closure provides abortability.
aoqi@0: 
aoqi@0: class Closure : public StackObj {
aoqi@0:  protected:
aoqi@0:   bool _abort;
aoqi@0:   void set_abort() { _abort = true; }
aoqi@0:  public:
aoqi@0:   Closure() : _abort(false) {}
aoqi@0:   // A subtype can use this mechanism to indicate to some iterator mapping
aoqi@0:   // functions that the iteration should cease.
aoqi@0:   bool abort() { return _abort; }
aoqi@0:   void clear_abort() { _abort = false; }
aoqi@0: };
aoqi@0: 
aoqi@0: // OopClosure is used for iterating through references to Java objects.
aoqi@0: 
aoqi@0: class OopClosure : public Closure {
aoqi@0:  public:
aoqi@0:   virtual void do_oop(oop* o) = 0;
aoqi@0:   virtual void do_oop_v(oop* o) { do_oop(o); }
aoqi@0:   virtual void do_oop(narrowOop* o) = 0;
aoqi@0:   virtual void do_oop_v(narrowOop* o) { do_oop(o); }
aoqi@0: };
aoqi@0: 
aoqi@0: // ExtendedOopClosure adds extra code to be run during oop iterations.
aoqi@0: // This is needed by the GC and is extracted to a separate type to not
aoqi@0: // pollute the OopClosure interface.
aoqi@0: class ExtendedOopClosure : public OopClosure {
aoqi@0:  public:
aoqi@0:   ReferenceProcessor* _ref_processor;
aoqi@0:   ExtendedOopClosure(ReferenceProcessor* rp) : _ref_processor(rp) { }
aoqi@0:   ExtendedOopClosure() : OopClosure(), _ref_processor(NULL) { }
aoqi@0: 
aoqi@0:   // If the do_metadata functions return "true",
aoqi@0:   // we invoke the following when running oop_iterate():
aoqi@0:   //
aoqi@0:   // 1) do_klass on the header klass pointer.
aoqi@0:   // 2) do_klass on the klass pointer in the mirrors.
aoqi@0:   // 3) do_class_loader_data on the class loader data in class loaders.
aoqi@0:   //
aoqi@0:   // The virtual (without suffix) and the non-virtual (with _nv suffix) need
aoqi@0:   // to be updated together, or else the devirtualization will break.
aoqi@0:   //
aoqi@0:   // Providing default implementations of the _nv functions unfortunately
aoqi@0:   // 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.
aoqi@0: 
aoqi@0:   virtual bool do_metadata() { return do_metadata_nv(); }
aoqi@0:   bool do_metadata_v()       { return do_metadata(); }
aoqi@0:   bool do_metadata_nv()      { return false; }
aoqi@0: 
aoqi@0:   virtual void do_klass(Klass* k)   { do_klass_nv(k); }
aoqi@0:   void do_klass_v(Klass* k)         { do_klass(k); }
aoqi@0:   void do_klass_nv(Klass* k)        { ShouldNotReachHere(); }
aoqi@0: 
aoqi@0:   virtual void do_class_loader_data(ClassLoaderData* cld) { ShouldNotReachHere(); }
aoqi@0: 
aoqi@0:   // Controls how prefetching is done for invocations of this closure.
aoqi@0:   Prefetch::style prefetch_style() { // Note that this is non-virtual.
aoqi@0:     return Prefetch::do_none;
aoqi@0:   }
aoqi@0: 
aoqi@0:   // True iff this closure may be safely applied more than once to an oop
aoqi@0:   // location without an intervening "major reset" (like the end of a GC).
aoqi@0:   virtual bool idempotent() { return false; }
aoqi@0:   virtual bool apply_to_weak_ref_discovered_field() { return false; }
aoqi@0: };
aoqi@0: 
aoqi@0: // Wrapper closure only used to implement oop_iterate_no_header().
aoqi@0: class NoHeaderExtendedOopClosure : public ExtendedOopClosure {
aoqi@0:   OopClosure* _wrapped_closure;
aoqi@0:  public:
aoqi@0:   NoHeaderExtendedOopClosure(OopClosure* cl) : _wrapped_closure(cl) {}
aoqi@0:   // Warning: this calls the virtual version do_oop in the the wrapped closure.
aoqi@0:   void do_oop_nv(oop* p)       { _wrapped_closure->do_oop(p); }
aoqi@0:   void do_oop_nv(narrowOop* p) { _wrapped_closure->do_oop(p); }
aoqi@0: 
aoqi@0:   void do_oop(oop* p)          { assert(false, "Only the _nv versions should be used");
aoqi@0:                                  _wrapped_closure->do_oop(p); }
aoqi@0:   void do_oop(narrowOop* p)    { assert(false, "Only the _nv versions should be used");
aoqi@0:                                  _wrapped_closure->do_oop(p);}
aoqi@0: };
aoqi@0: 
aoqi@0: class KlassClosure : public Closure {
aoqi@0:  public:
aoqi@0:   virtual void do_klass(Klass* k) = 0;
aoqi@0: };
aoqi@0: 
stefank@6973: class CLDClosure : public Closure {
stefank@6973:  public:
stefank@6973:   virtual void do_cld(ClassLoaderData* cld) = 0;
stefank@6973: };
stefank@6973: 
aoqi@0: class KlassToOopClosure : public KlassClosure {
stefank@6982:   friend class MetadataAwareOopClosure;
stefank@6982:   friend class MetadataAwareOopsInGenClosure;
stefank@6982: 
aoqi@0:   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: 
aoqi@0:  public:
stefank@6982:   KlassToOopClosure(OopClosure* oop_closure = NULL) : _oop_closure(oop_closure) {}
stefank@6992: 
aoqi@0:   virtual void do_klass(Klass* k);
aoqi@0: };
aoqi@0: 
stefank@6973: class CLDToOopClosure : public CLDClosure {
stefank@6992:   OopClosure*       _oop_closure;
aoqi@0:   KlassToOopClosure _klass_closure;
stefank@6992:   bool              _must_claim_cld;
aoqi@0: 
aoqi@0:  public:
aoqi@0:   CLDToOopClosure(OopClosure* oop_closure, bool must_claim_cld = true) :
aoqi@0:       _oop_closure(oop_closure),
aoqi@0:       _klass_closure(oop_closure),
aoqi@0:       _must_claim_cld(must_claim_cld) {}
aoqi@0: 
aoqi@0:   void do_cld(ClassLoaderData* cld);
aoqi@0: };
aoqi@0: 
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: 
aoqi@0: // ObjectClosure is used for iterating through an object space
aoqi@0: 
aoqi@0: class ObjectClosure : public Closure {
aoqi@0:  public:
aoqi@0:   // Called for each object.
aoqi@0:   virtual void do_object(oop obj) = 0;
aoqi@0: };
aoqi@0: 
aoqi@0: 
aoqi@0: class BoolObjectClosure : public Closure {
aoqi@0:  public:
aoqi@0:   virtual bool do_object_b(oop obj) = 0;
aoqi@0: };
aoqi@0: 
aoqi@0: // Applies an oop closure to all ref fields in objects iterated over in an
aoqi@0: // object iteration.
aoqi@0: class ObjectToOopClosure: public ObjectClosure {
aoqi@0:   ExtendedOopClosure* _cl;
aoqi@0: public:
aoqi@0:   void do_object(oop obj);
aoqi@0:   ObjectToOopClosure(ExtendedOopClosure* cl) : _cl(cl) {}
aoqi@0: };
aoqi@0: 
aoqi@0: // A version of ObjectClosure that is expected to be robust
aoqi@0: // in the face of possibly uninitialized objects.
aoqi@0: class ObjectClosureCareful : public ObjectClosure {
aoqi@0:  public:
aoqi@0:   virtual size_t do_object_careful_m(oop p, MemRegion mr) = 0;
aoqi@0:   virtual size_t do_object_careful(oop p) = 0;
aoqi@0: };
aoqi@0: 
aoqi@0: // The following are used in CompactibleFreeListSpace and
aoqi@0: // ConcurrentMarkSweepGeneration.
aoqi@0: 
aoqi@0: // Blk closure (abstract class)
aoqi@0: class BlkClosure : public StackObj {
aoqi@0:  public:
aoqi@0:   virtual size_t do_blk(HeapWord* addr) = 0;
aoqi@0: };
aoqi@0: 
aoqi@0: // A version of BlkClosure that is expected to be robust
aoqi@0: // in the face of possibly uninitialized objects.
aoqi@0: class BlkClosureCareful : public BlkClosure {
aoqi@0:  public:
aoqi@0:   size_t do_blk(HeapWord* addr) {
aoqi@0:     guarantee(false, "call do_blk_careful instead");
aoqi@0:     return 0;
aoqi@0:   }
aoqi@0:   virtual size_t do_blk_careful(HeapWord* addr) = 0;
aoqi@0: };
aoqi@0: 
aoqi@0: // SpaceClosure is used for iterating over spaces
aoqi@0: 
aoqi@0: class Space;
aoqi@0: class CompactibleSpace;
aoqi@0: 
aoqi@0: class SpaceClosure : public StackObj {
aoqi@0:  public:
aoqi@0:   // Called for each space
aoqi@0:   virtual void do_space(Space* s) = 0;
aoqi@0: };
aoqi@0: 
aoqi@0: class CompactibleSpaceClosure : public StackObj {
aoqi@0:  public:
aoqi@0:   // Called for each compactible space
aoqi@0:   virtual void do_space(CompactibleSpace* s) = 0;
aoqi@0: };
aoqi@0: 
aoqi@0: 
aoqi@0: // CodeBlobClosure is used for iterating through code blobs
aoqi@0: // in the code cache or on thread stacks
aoqi@0: 
aoqi@0: class CodeBlobClosure : public Closure {
aoqi@0:  public:
aoqi@0:   // Called for each code blob.
aoqi@0:   virtual void do_code_blob(CodeBlob* cb) = 0;
aoqi@0: };
aoqi@0: 
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);
aoqi@0: 
stefank@6992:   const static bool FixRelocations = true;
stefank@6992: };
stefank@6992: 
stefank@6992: class MarkingCodeBlobClosure : public CodeBlobToOopClosure {
aoqi@0:  public:
stefank@6992:   MarkingCodeBlobClosure(OopClosure* cl, bool fix_relocations) : CodeBlobToOopClosure(cl, fix_relocations) {}
aoqi@0:   // Called for each code blob, but at most once per unique blob.
aoqi@0: 
aoqi@0:   virtual void do_code_blob(CodeBlob* cb);
aoqi@0: 
aoqi@0:   class MarkScope : public StackObj {
aoqi@0:   protected:
aoqi@0:     bool _active;
aoqi@0:   public:
aoqi@0:     MarkScope(bool activate = true);
aoqi@0:       // = { if (active) nmethod::oops_do_marking_prologue(); }
aoqi@0:     ~MarkScope();
aoqi@0:       // = { if (active) nmethod::oops_do_marking_epilogue(); }
aoqi@0:   };
aoqi@0: };
aoqi@0: 
aoqi@0: // MonitorClosure is used for iterating over monitors in the monitors cache
aoqi@0: 
aoqi@0: class ObjectMonitor;
aoqi@0: 
aoqi@0: class MonitorClosure : public StackObj {
aoqi@0:  public:
aoqi@0:   // called for each monitor in cache
aoqi@0:   virtual void do_monitor(ObjectMonitor* m) = 0;
aoqi@0: };
aoqi@0: 
aoqi@0: // A closure that is applied without any arguments.
aoqi@0: class VoidClosure : public StackObj {
aoqi@0:  public:
aoqi@0:   // I would have liked to declare this a pure virtual, but that breaks
aoqi@0:   // in mysterious ways, for unknown reasons.
aoqi@0:   virtual void do_void();
aoqi@0: };
aoqi@0: 
aoqi@0: 
aoqi@0: // YieldClosure is intended for use by iteration loops
aoqi@0: // to incrementalize their work, allowing interleaving
aoqi@0: // of an interruptable task so as to allow other
aoqi@0: // threads to run (which may not otherwise be able to access
aoqi@0: // exclusive resources, for instance). Additionally, the
aoqi@0: // closure also allows for aborting an ongoing iteration
aoqi@0: // by means of checking the return value from the polling
aoqi@0: // call.
aoqi@0: class YieldClosure : public StackObj {
aoqi@0:   public:
aoqi@0:    virtual bool should_return() = 0;
aoqi@0: };
aoqi@0: 
aoqi@0: // Abstract closure for serializing data (read or write).
aoqi@0: 
aoqi@0: class SerializeClosure : public Closure {
aoqi@0: public:
aoqi@0:   // Return bool indicating whether closure implements read or write.
aoqi@0:   virtual bool reading() const = 0;
aoqi@0: 
aoqi@0:   // Read/write the void pointer pointed to by p.
aoqi@0:   virtual void do_ptr(void** p) = 0;
aoqi@0: 
aoqi@0:   // Read/write the region specified.
aoqi@0:   virtual void do_region(u_char* start, size_t size) = 0;
aoqi@0: 
aoqi@0:   // Check/write the tag.  If reading, then compare the tag against
aoqi@0:   // the passed in value and fail is they don't match.  This allows
aoqi@0:   // for verification that sections of the serialized data are of the
aoqi@0:   // correct length.
aoqi@0:   virtual void do_tag(int tag) = 0;
aoqi@0: };
aoqi@0: 
aoqi@0: class SymbolClosure : public StackObj {
aoqi@0:  public:
aoqi@0:   virtual void do_symbol(Symbol**) = 0;
aoqi@0: 
aoqi@0:   // Clear LSB in symbol address; it can be set by CPSlot.
aoqi@0:   static Symbol* load_symbol(Symbol** p) {
aoqi@0:     return (Symbol*)(intptr_t(*p) & ~1);
aoqi@0:   }
aoqi@0: 
aoqi@0:   // Store symbol, adjusting new pointer if the original pointer was adjusted
aoqi@0:   // (symbol references in constant pool slots have their LSB set to 1).
aoqi@0:   static void store_symbol(Symbol** p, Symbol* sym) {
aoqi@0:     *p = (Symbol*)(intptr_t(sym) | (intptr_t(*p) & 1));
aoqi@0:   }
aoqi@0: };
aoqi@0: 
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: 
aoqi@0: #endif // SHARE_VM_MEMORY_ITERATOR_HPP