| /* |
| * Copyright (c) 1997, 2017, 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 "oops/oopsHierarchy.hpp" |
| |
| class CodeBlob; |
| class nmethod; |
| class ReferenceProcessor; |
| class DataLayout; |
| class KlassClosure; |
| class ClassLoaderData; |
| class Symbol; |
| |
| // The following classes are C++ `closures` for iterating over objects, roots and spaces |
| |
| class Closure : public StackObj { }; |
| |
| // 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(narrowOop* o) = 0; |
| }; |
| |
| // 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 { |
| private: |
| ReferenceProcessor* _ref_processor; |
| |
| protected: |
| ExtendedOopClosure(ReferenceProcessor* rp) : _ref_processor(rp) { } |
| ExtendedOopClosure() : _ref_processor(NULL) { } |
| ~ExtendedOopClosure() { } |
| |
| void set_ref_processor_internal(ReferenceProcessor* rp) { _ref_processor = rp; } |
| |
| public: |
| ReferenceProcessor* ref_processor() const { return _ref_processor; } |
| |
| // Iteration of InstanceRefKlasses differ depending on the closure, |
| // the below enum describes the different alternatives. |
| enum ReferenceIterationMode { |
| DO_DISCOVERY, // Apply closure and discover references |
| DO_DISCOVERED_AND_DISCOVERY, // Apply closure to discovered field and do discovery |
| DO_FIELDS // Apply closure to all fields |
| }; |
| |
| // The default iteration mode is to do discovery. |
| virtual ReferenceIterationMode reference_iteration_mode() { return DO_DISCOVERY; } |
| |
| // 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_cld 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. |
| |
| bool do_metadata_nv() { return false; } |
| virtual bool do_metadata() { return do_metadata_nv(); } |
| |
| void do_klass_nv(Klass* k) { ShouldNotReachHere(); } |
| virtual void do_klass(Klass* k) { do_klass_nv(k); } |
| |
| void do_cld_nv(ClassLoaderData* cld) { ShouldNotReachHere(); } |
| virtual void do_cld(ClassLoaderData* cld) { do_cld_nv(cld); } |
| |
| // 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; } |
| |
| #ifdef ASSERT |
| // Default verification of each visited oop field. |
| template <typename T> void verify(T* p); |
| |
| // Can be used by subclasses to turn off the default verification of oop fields. |
| virtual bool should_verify_oops() { return true; } |
| #endif |
| }; |
| |
| // 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 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); |
| } |
| |
| bool do_metadata_nv() { return true; } |
| virtual bool do_metadata() { return do_metadata_nv(); } |
| |
| void do_klass_nv(Klass* k); |
| virtual void do_klass(Klass* k) { do_klass_nv(k); } |
| |
| void do_cld_nv(ClassLoaderData* cld); |
| virtual void do_cld(ClassLoaderData* cld) { do_cld_nv(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; |
| }; |
| |
| class AlwaysTrueClosure: public BoolObjectClosure { |
| public: |
| bool do_object_b(oop p) { return true; } |
| }; |
| |
| class AlwaysFalseClosure : public BoolObjectClosure { |
| public: |
| bool do_object_b(oop p) { return false; } |
| }; |
| |
| // 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: |
| // If fix_relocations(), then cl must copy objects to their new location immediately to avoid |
| // patching nmethods with the old locations. |
| CodeBlobToOopClosure(OopClosure* cl, bool fix_relocations) : _cl(cl), _fix_relocations(fix_relocations) {} |
| virtual void do_code_blob(CodeBlob* cb); |
| |
| bool fix_relocations() const { return _fix_relocations; } |
| 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); |
| }; |
| |
| // 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 32-bit unsigned integer pointed to by p. |
| virtual void do_u4(u4* 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; |
| |
| bool writing() { |
| return !reading(); |
| } |
| }; |
| |
| 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)); |
| } |
| }; |
| |
| // The two class template specializations are used to dispatch calls |
| // to the ExtendedOopClosure functions. If use_non_virtual_call is true, |
| // the non-virtual versions are called (E.g. do_oop_nv), otherwise the |
| // virtual versions are called (E.g. do_oop). |
| |
| template <bool use_non_virtual_call> |
| class Devirtualizer {}; |
| |
| // Dispatches to the non-virtual functions. |
| template <> class Devirtualizer<true> { |
| public: |
| template <class OopClosureType, typename T> static void do_oop(OopClosureType* closure, T* p); |
| template <class OopClosureType> static void do_klass(OopClosureType* closure, Klass* k); |
| template <class OopClosureType> static void do_cld(OopClosureType* closure, ClassLoaderData* cld); |
| template <class OopClosureType> static bool do_metadata(OopClosureType* closure); |
| }; |
| |
| // Dispatches to the virtual functions. |
| template <> class Devirtualizer<false> { |
| public: |
| template <class OopClosureType, typename T> static void do_oop(OopClosureType* closure, T* p); |
| template <class OopClosureType> static void do_klass(OopClosureType* closure, Klass* k); |
| template <class OopClosureType> static void do_cld(OopClosureType* closure, ClassLoaderData* cld); |
| template <class OopClosureType> static bool do_metadata(OopClosureType* closure); |
| }; |
| |
| #endif // SHARE_VM_MEMORY_ITERATOR_HPP |