Mercurial > hg > truffle
view src/share/vm/memory/iterator.hpp @ 3273:df22fe9c5a93
Merge
author | coleenp |
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date | Wed, 27 Apr 2011 17:25:45 -0700 |
parents | 1d1603768966 |
children | da91efe96a93 |
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/* * Copyright (c) 1997, 2011, 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; // 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 roots (oop*) class OopClosure : public Closure { public: ReferenceProcessor* _ref_processor; OopClosure(ReferenceProcessor* rp) : _ref_processor(rp) { } OopClosure() : _ref_processor(NULL) { } 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); } // In support of post-processing of weak links of KlassKlass objects; // see KlassKlass::oop_oop_iterate(). virtual const bool should_remember_klasses() const { assert(!must_remember_klasses(), "Should have overriden this method."); return false; } virtual void remember_klass(Klass* k) { /* do nothing */ } // In support of post-processing of weak references in // ProfileData (MethodDataOop) objects; see, for example, // VirtualCallData::oop_iterate(). virtual const bool should_remember_mdo() const { return false; } virtual void remember_mdo(DataLayout* v) { /* do nothing */ } // The methods below control how object iterations invoking this closure // should be performed: // If "true", invoke on header klass field. bool do_header() { return true; } // Note that this is non-virtual. // 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; } #ifdef ASSERT static bool _must_remember_klasses; static bool must_remember_klasses(); static void set_must_remember_klasses(bool v); #endif }; // 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 ObjectClosure { 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 { OopClosure* _cl; public: void do_object(oop obj); ObjectToOopClosure(OopClosure* cl) : _cl(cl) {} }; // A version of ObjectClosure with "memory" (see _previous_address below) class UpwardsObjectClosure: public BoolObjectClosure { HeapWord* _previous_address; public: UpwardsObjectClosure() : _previous_address(NULL) { } void set_previous(HeapWord* addr) { _previous_address = addr; } HeapWord* previous() { return _previous_address; } // A return value of "true" can be used by the caller to decide // if this object's end should *NOT* be recorded in // _previous_address above. virtual bool do_object_bm(oop obj, MemRegion mr) = 0; }; // 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; }; class MarkingCodeBlobClosure : public CodeBlobClosure { public: // Called for each code blob, but at most once per unique blob. virtual void do_newly_marked_nmethod(nmethod* nm) = 0; virtual void do_code_blob(CodeBlob* cb); // = { if (!nmethod(cb)->test_set_oops_do_mark()) do_newly_marked_nmethod(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(); } }; }; // Applies an oop closure to all ref fields in code blobs // iterated over in an object iteration. class CodeBlobToOopClosure: public MarkingCodeBlobClosure { OopClosure* _cl; bool _do_marking; public: virtual void do_newly_marked_nmethod(nmethod* cb); // = { cb->oops_do(_cl); } virtual void do_code_blob(CodeBlob* cb); // = { if (_do_marking) super::do_code_blob(cb); else cb->oops_do(_cl); } CodeBlobToOopClosure(OopClosure* cl, bool do_marking) : _cl(cl), _do_marking(do_marking) {} }; // 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 SerializeOopClosure : public OopClosure { public: // Return bool indicating whether closure implements read or write. virtual bool reading() const = 0; // Read/write the int pointed to by i. virtual void do_int(int* i) = 0; // Read/write the size_t pointed to by i. virtual void do_size_t(size_t* i) = 0; // Read/write the void pointer pointed to by p. virtual void do_ptr(void** p) = 0; // Read/write the HeapWord pointer pointed to be p. virtual void do_ptr(HeapWord** 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)); } }; #ifdef ASSERT // This class is used to flag phases of a collection that // can unload classes and which should override the // should_remember_klasses() and remember_klass() of OopClosure. // The _must_remember_klasses is set in the contructor and restored // in the destructor. _must_remember_klasses is checked in assertions // in the OopClosure implementations of should_remember_klasses() and // remember_klass() and the expectation is that the OopClosure // implementation should not be in use if _must_remember_klasses is set. // Instances of RememberKlassesChecker can be place in // marking phases of collections which can do class unloading. // RememberKlassesChecker can be passed "false" to turn off checking. // It is used by CMS when CMS yields to a different collector. class RememberKlassesChecker: StackObj { bool _saved_state; bool _do_check; public: RememberKlassesChecker(bool checking_on) : _saved_state(false), _do_check(true) { // The ClassUnloading unloading flag affects the collectors except // for CMS. // CMS unloads classes if CMSClassUnloadingEnabled is true or // if ExplicitGCInvokesConcurrentAndUnloadsClasses is true and // the current collection is an explicit collection. Turning // on the checking in general for // ExplicitGCInvokesConcurrentAndUnloadsClasses and // UseConcMarkSweepGC should not lead to false positives. _do_check = ClassUnloading && !UseConcMarkSweepGC || CMSClassUnloadingEnabled && UseConcMarkSweepGC || ExplicitGCInvokesConcurrentAndUnloadsClasses && UseConcMarkSweepGC; if (_do_check) { _saved_state = OopClosure::must_remember_klasses(); OopClosure::set_must_remember_klasses(checking_on); } } ~RememberKlassesChecker() { if (_do_check) { OopClosure::set_must_remember_klasses(_saved_state); } } }; #endif // ASSERT #endif // SHARE_VM_MEMORY_ITERATOR_HPP