/* * Copyright (c) 1997, 2014, 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_OOPS_OOP_HPP #define SHARE_VM_OOPS_OOP_HPP #include "memory/iterator.hpp" #include "memory/memRegion.hpp" #include "memory/specialized_oop_closures.inline.hpp" #include "oops/metadata.hpp" #include "utilities/macros.hpp" #include "utilities/top.hpp" #include "utilities/templateIdioms.hpp" // oopDesc is the top baseclass for objects classes. The {name}Desc classes describe // the format of Java objects so the fields can be accessed from C++. // oopDesc is abstract. // (see oopHierarchy for complete oop class hierarchy) // // no virtual functions allowed // store into oop with store check template void oop_store(T* p, oop v); template void oop_store(volatile T* p, oop v); extern bool always_do_update_barrier; // Forward declarations. class OopClosure; class ScanClosure; class FastScanClosure; class FilteringClosure; class BarrierSet; class CMSIsAliveClosure; class PSPromotionManager; class ParCompactionManager; class oopDesc { friend class VMStructs; private: volatile markOop _mark; union _metadata { Klass* _klass; narrowKlass _compressed_klass; } _metadata; // Fast access to barrier set. Must be initialized. static BarrierSet* _bs; public: markOop mark() const { return _mark; } markOop* mark_addr() const { return (markOop*) &_mark; } void set_mark(volatile markOop m) { _mark = m; } void release_set_mark(markOop m); markOop cas_set_mark(markOop new_mark, markOop old_mark); // Used only to re-initialize the mark word (e.g., of promoted // objects during a GC) -- requires a valid klass pointer void init_mark(); Klass* klass() const; Klass* klass_or_null() const volatile; Klass** klass_addr(); narrowKlass* compressed_klass_addr(); void set_klass(Klass* k); // For klass field compression int klass_gap() const; void set_klass_gap(int z); // For when the klass pointer is being used as a linked list "next" field. void set_klass_to_list_ptr(oop k); oop list_ptr_from_klass(); // size of object header, aligned to platform wordSize static int header_size() { return sizeof(oopDesc)/HeapWordSize; } // Returns whether this is an instance of k or an instance of a subclass of k bool is_a(Klass* k) const; // Returns the actual oop size of the object int size(); // Sometimes (for complicated concurrency-related reasons), it is useful // to be able to figure out the size of an object knowing its klass. int size_given_klass(Klass* klass); // type test operations (inlined in oop.inline.h) bool is_instance() const; bool is_instanceMirror() const; bool is_instanceClassLoader() const; bool is_instanceRef() const; bool is_array() const; bool is_objArray() const; bool is_typeArray() const; private: // field addresses in oop void* field_base(int offset) const; jbyte* byte_field_addr(int offset) const; jchar* char_field_addr(int offset) const; jboolean* bool_field_addr(int offset) const; jint* int_field_addr(int offset) const; jshort* short_field_addr(int offset) const; jlong* long_field_addr(int offset) const; jfloat* float_field_addr(int offset) const; jdouble* double_field_addr(int offset) const; Metadata** metadata_field_addr(int offset) const; public: // Need this as public for garbage collection. template T* obj_field_addr(int offset) const; // Needed for javaClasses address* address_field_addr(int offset) const; static bool is_null(oop obj); static bool is_null(narrowOop obj); static bool is_null(Klass* obj); // Decode an oop pointer from a narrowOop if compressed. // These are overloaded for oop and narrowOop as are the other functions // below so that they can be called in template functions. static oop decode_heap_oop_not_null(oop v); static oop decode_heap_oop_not_null(narrowOop v); static oop decode_heap_oop(oop v); static oop decode_heap_oop(narrowOop v); // Encode an oop pointer to a narrow oop. The or_null versions accept // null oop pointer, others do not in order to eliminate the // null checking branches. static narrowOop encode_heap_oop_not_null(oop v); static narrowOop encode_heap_oop(oop v); // Load an oop out of the Java heap static narrowOop load_heap_oop(narrowOop* p); static oop load_heap_oop(oop* p); // Load an oop out of Java heap and decode it to an uncompressed oop. static oop load_decode_heap_oop_not_null(narrowOop* p); static oop load_decode_heap_oop_not_null(oop* p); static oop load_decode_heap_oop(narrowOop* p); static oop load_decode_heap_oop(oop* p); // Store an oop into the heap. static void store_heap_oop(narrowOop* p, narrowOop v); static void store_heap_oop(oop* p, oop v); // Encode oop if UseCompressedOops and store into the heap. static void encode_store_heap_oop_not_null(narrowOop* p, oop v); static void encode_store_heap_oop_not_null(oop* p, oop v); static void encode_store_heap_oop(narrowOop* p, oop v); static void encode_store_heap_oop(oop* p, oop v); static void release_store_heap_oop(volatile narrowOop* p, narrowOop v); static void release_store_heap_oop(volatile oop* p, oop v); static void release_encode_store_heap_oop_not_null(volatile narrowOop* p, oop v); static void release_encode_store_heap_oop_not_null(volatile oop* p, oop v); static void release_encode_store_heap_oop(volatile narrowOop* p, oop v); static void release_encode_store_heap_oop(volatile oop* p, oop v); static oop atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest); static oop atomic_compare_exchange_oop(oop exchange_value, volatile HeapWord *dest, oop compare_value, bool prebarrier = false); // Access to fields in a instanceOop through these methods. oop obj_field(int offset) const; volatile oop obj_field_volatile(int offset) const; void obj_field_put(int offset, oop value); void obj_field_put_raw(int offset, oop value); void obj_field_put_volatile(int offset, oop value); Metadata* metadata_field(int offset) const; void metadata_field_put(int offset, Metadata* value); jbyte byte_field(int offset) const; void byte_field_put(int offset, jbyte contents); jchar char_field(int offset) const; void char_field_put(int offset, jchar contents); jboolean bool_field(int offset) const; void bool_field_put(int offset, jboolean contents); jint int_field(int offset) const; void int_field_put(int offset, jint contents); jshort short_field(int offset) const; void short_field_put(int offset, jshort contents); jlong long_field(int offset) const; void long_field_put(int offset, jlong contents); jfloat float_field(int offset) const; void float_field_put(int offset, jfloat contents); jdouble double_field(int offset) const; void double_field_put(int offset, jdouble contents); address address_field(int offset) const; void address_field_put(int offset, address contents); oop obj_field_acquire(int offset) const; void release_obj_field_put(int offset, oop value); jbyte byte_field_acquire(int offset) const; void release_byte_field_put(int offset, jbyte contents); jchar char_field_acquire(int offset) const; void release_char_field_put(int offset, jchar contents); jboolean bool_field_acquire(int offset) const; void release_bool_field_put(int offset, jboolean contents); jint int_field_acquire(int offset) const; void release_int_field_put(int offset, jint contents); jshort short_field_acquire(int offset) const; void release_short_field_put(int offset, jshort contents); jlong long_field_acquire(int offset) const; void release_long_field_put(int offset, jlong contents); jfloat float_field_acquire(int offset) const; void release_float_field_put(int offset, jfloat contents); jdouble double_field_acquire(int offset) const; void release_double_field_put(int offset, jdouble contents); address address_field_acquire(int offset) const; void release_address_field_put(int offset, address contents); // printing functions for VM debugging void print_on(outputStream* st) const; // First level print void print_value_on(outputStream* st) const; // Second level print. void print_address_on(outputStream* st) const; // Address printing // printing on default output stream void print(); void print_value(); void print_address(); // return the print strings char* print_string(); char* print_value_string(); // verification operations void verify_on(outputStream* st); void verify(); // locking operations bool is_locked() const; bool is_unlocked() const; bool has_bias_pattern() const; // asserts bool is_oop(bool ignore_mark_word = false) const; bool is_oop_or_null(bool ignore_mark_word = false) const; #ifndef PRODUCT bool is_unlocked_oop() const; #endif // garbage collection bool is_gc_marked() const; // Apply "MarkSweep::mark_and_push" to (the address of) every non-NULL // reference field in "this". void follow_contents(void); #if INCLUDE_ALL_GCS // Parallel Scavenge void push_contents(PSPromotionManager* pm); // Parallel Old void update_contents(ParCompactionManager* cm); void follow_contents(ParCompactionManager* cm); #endif // INCLUDE_ALL_GCS bool is_scavengable() const; // Forward pointer operations for scavenge bool is_forwarded() const; void forward_to(oop p); bool cas_forward_to(oop p, markOop compare); #if INCLUDE_ALL_GCS // Like "forward_to", but inserts the forwarding pointer atomically. // Exactly one thread succeeds in inserting the forwarding pointer, and // this call returns "NULL" for that thread; any other thread has the // value of the forwarding pointer returned and does not modify "this". oop forward_to_atomic(oop p); #endif // INCLUDE_ALL_GCS oop forwardee() const; // Age of object during scavenge uint age() const; void incr_age(); // Adjust all pointers in this object to point at it's forwarded location and // return the size of this oop. This is used by the MarkSweep collector. int adjust_pointers(); // mark-sweep support void follow_body(int begin, int end); // Fast access to barrier set static BarrierSet* bs() { return _bs; } static void set_bs(BarrierSet* bs) { _bs = bs; } private: // Dispatch member functions to oop closures template typename enable_if::value, void>::type do_metadata_if_applicable(OopClosureType *cl); template typename enable_if::value, void>::type do_metadata_if_applicable(OopClosureType *cl); template int oop_iterate_dispatch_tag(OopClosureType *blk, DispatchTag tag); template int oop_iterate_internal(OopClosureType *blk); public: template typename enable_if::value, int>::type oop_iterate(OopClosureType *blk); // iterators, returns size of object #define OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ int oop_iterate(OopClosureType* blk); \ int oop_iterate(OopClosureType* blk, MemRegion mr); // Only in mr. ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL) ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL) #if INCLUDE_ALL_GCS #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \ int oop_iterate_backwards(OopClosureType* blk); ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL) ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL) #endif template typename enable_if::value, int>::type oop_iterate_no_header(OopClosureType* bk); int oop_iterate_no_header(OopClosure* bk, MemRegion mr); // identity hash; returns the identity hash key (computes it if necessary) // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a // safepoint if called on a biased object. Calling code must be aware of that. intptr_t identity_hash(); intptr_t slow_identity_hash(); // Alternate hashing code if string table is rehashed unsigned int new_hash(juint seed); // marks are forwarded to stack when object is locked bool has_displaced_mark() const; markOop displaced_mark() const; void set_displaced_mark(markOop m); // for code generation static int mark_offset_in_bytes() { return offset_of(oopDesc, _mark); } static int klass_offset_in_bytes() { return offset_of(oopDesc, _metadata._klass); } static int klass_gap_offset_in_bytes(); }; #endif // SHARE_VM_OOPS_OOP_HPP