/* * Copyright (c) 1997, 2019, 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_OOPS_OOP_HPP #define SHARE_OOPS_OOP_HPP #include "memory/iterator.hpp" #include "memory/memRegion.hpp" #include "oops/access.hpp" #include "oops/arrayStorageProperties.hpp" #include "oops/metadata.hpp" #include "runtime/atomic.hpp" #include "utilities/macros.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 // // oopDesc::_mark - the "oop mark word" encoding to be found separately in markOop.hpp // // oopDesc::_metadata - encodes both the object's klass pointer and potentially // "storage properties" (currently confined to arrays in the form of // ArrayStorageProperties). Storage properties are peculiar to the // *instance*, and not necessarily the "type". // // The overall size of the _metadata field is dependent on "UseCompressedClassPointers", // hence the terms "narrow" (32 bits) vs "wide" (64 bits). // // "Wide" encoding of _metadata: // bit number |63 0| // bit length |--3|-----61-----| // -------------------------------------- // _klass [xxx| Klass* ] // _wide_storage_props [ sp| ] // -------------------------------------- // with: // xxx = klass_mask(), Klass* = Klass pointer to be masked // sp = storage properties, bit number: wide_storage_props_shift // // "Narrow" encoding of _metadata: // bit number |31 0| // bit length |--3|-----29-----| // ---------------------------------------- // _compressed_klass [xxx| narrowKlass] // _narrow_storage_props [ sp| ] // ---------------------------------------- // with: // xxx = compressed_klass_mask(), narrowKlass = compressed Klass pointer to be masked // narrowKlass may be further decoded (Klass::decode_klass()) to produce Klass* // sp = storage properties, bit number: narrow_storage_props_shift // // Storage properties encodings are current confined to arrayStorageProperties.hpp extern bool always_do_update_barrier; // Forward declarations. class OopClosure; class ScanClosure; class FastScanClosure; class FilteringClosure; class CMSIsAliveClosure; class PSPromotionManager; class ParCompactionManager; class oopDesc { friend class VMStructs; friend class JVMCIVMStructs; private: volatile markOop _mark; union _metadata { Klass* _klass; narrowKlass _compressed_klass; uintptr_t _wide_storage_props; uint32_t _narrow_storage_props; } _metadata; public: inline markOop mark() const; inline markOop mark_raw() const; inline markOop* mark_addr_raw() const; inline void set_mark(volatile markOop m); inline void set_mark_raw(volatile markOop m); static inline void set_mark_raw(HeapWord* mem, markOop m); inline void release_set_mark(markOop m); inline markOop cas_set_mark(markOop new_mark, markOop old_mark); inline markOop cas_set_mark_raw(markOop new_mark, markOop old_mark, atomic_memory_order order = memory_order_conservative); // Used only to re-initialize the mark word (e.g., of promoted // objects during a GC) -- requires a valid klass pointer inline void init_mark(); inline void init_mark_raw(); enum { storage_props_nof_bits = LogKlassAlignmentInBytes, // This alignment gives us some "free bits" narrow_storage_props_shift = (sizeof(narrowKlass) << 3) - storage_props_nof_bits, wide_storage_props_shift = (sizeof(Klass*) << 3) - storage_props_nof_bits, }; static inline narrowKlass compressed_klass_mask(); static inline narrowKlass compressed_klass_masked(narrowKlass raw); static inline uintptr_t klass_mask(); static inline Klass* klass_masked(uintptr_t raw); inline Klass* klass() const; inline Klass* klass_or_null() const volatile; inline Klass* klass_or_null_acquire() const volatile; static inline Klass** klass_addr(HeapWord* mem); static inline narrowKlass* compressed_klass_addr(HeapWord* mem); inline Klass** klass_addr(); inline narrowKlass* compressed_klass_addr(); inline void set_klass(Klass* k); static inline void release_set_klass(HeapWord* mem, Klass* klass); // Extra container metadata specific to arrays (encoded into high bits of _metadata) static inline uintptr_t* wide_metadata_addr(HeapWord* mem); inline ArrayStorageProperties array_storage_properties() const; inline void set_metadata(ArrayStorageProperties storage_props, Klass* k); static inline void release_set_metadata(HeapWord* mem, ArrayStorageProperties storage_props, Klass* klass); // For klass field compression inline int klass_gap() const; inline void set_klass_gap(int z); static inline void set_klass_gap(HeapWord* mem, int z); // For when the klass pointer is being used as a linked list "next" field. inline void set_klass_to_list_ptr(oop k); inline 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 inline bool is_a(Klass* k) const; // Returns the actual oop size of the object inline 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. inline int size_given_klass(Klass* klass); // type test operations (inlined in oop.inline.hpp) inline bool is_instance() const; inline bool is_array() const; inline bool is_objArray() const; inline bool is_typeArray() const; inline bool is_value() const; inline bool is_valueArray() const; // type test operations that don't require inclusion of oop.inline.hpp. bool is_instance_noinline() const; bool is_array_noinline() const; bool is_objArray_noinline() const; bool is_typeArray_noinline() const; bool is_value_noinline() const; bool is_valueArray_noinline() const; protected: inline oop as_oop() const { return const_cast(this); } public: // field addresses in oop inline void* field_addr(int offset) const; inline void* field_addr_raw(int offset) const; // Need this as public for garbage collection. template inline T* obj_field_addr_raw(int offset) const; template inline size_t field_offset(T* p) const; // Standard compare function returns negative value if o1 < o2 // 0 if o1 == o2 // positive value if o1 > o2 inline static int compare(oop o1, oop o2) { void* o1_addr = (void*)o1; void* o2_addr = (void*)o2; if (o1_addr < o2_addr) { return -1; } else if (o1_addr > o2_addr) { return 1; } else { return 0; } } inline static bool equals(oop o1, oop o2) { return Access<>::equals(o1, o2); } inline static bool equals_raw(oop o1, oop o2) { return RawAccess<>::equals(o1, o2); } // Access to fields in a instanceOop through these methods. template oop obj_field_access(int offset) const; oop obj_field(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; Metadata* metadata_field_raw(int offset) const; void metadata_field_put(int offset, Metadata* value); Metadata* metadata_field_acquire(int offset) const; void release_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; jint int_field_raw(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 static void verify_on(outputStream* st, oopDesc* oop_desc); static void verify(oopDesc* oopDesc); // locking operations inline bool is_locked() const; inline bool is_unlocked() const; inline bool has_bias_pattern() const; inline bool has_bias_pattern_raw() const; // asserts and guarantees static bool is_oop(oop obj, bool ignore_mark_word = false); static bool is_oop_or_null(oop obj, bool ignore_mark_word = false); #ifndef PRODUCT inline bool is_unlocked_oop() const; static bool is_archived_object(oop p) NOT_CDS_JAVA_HEAP_RETURN_(false); #endif // garbage collection inline bool is_gc_marked() const; // Forward pointer operations for scavenge inline bool is_forwarded() const; inline void forward_to(oop p); inline bool cas_forward_to(oop p, markOop compare, atomic_memory_order order = memory_order_conservative); // 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". inline oop forward_to_atomic(oop p, markOop compare, atomic_memory_order order = memory_order_conservative); inline oop forwardee() const; inline oop forwardee_acquire() const; // Age of object during scavenge inline uint age() const; inline void incr_age(); // mark-sweep support void follow_body(int begin, int end); template inline void oop_iterate(OopClosureType* cl); template inline void oop_iterate(OopClosureType* cl, MemRegion mr); template inline int oop_iterate_size(OopClosureType* cl); template inline int oop_iterate_size(OopClosureType* cl, MemRegion mr); template inline void oop_iterate_backwards(OopClosureType* cl); inline static bool is_instanceof_or_null(oop obj, Klass* klass); // 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. inline intptr_t identity_hash(); intptr_t slow_identity_hash(); // marks are forwarded to stack when object is locked inline bool has_displaced_mark_raw() const; inline markOop displaced_mark_raw() const; inline void set_displaced_mark_raw(markOop m); static bool has_klass_gap(); // 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() { assert(has_klass_gap(), "only applicable to compressed klass pointers"); return klass_offset_in_bytes() + sizeof(narrowKlass); } // for error reporting static oop decode_oop_raw(narrowOop narrow_oop); static void* load_klass_raw(oop obj); static void* load_oop_raw(oop obj, int offset); static bool is_valid(oop obj); static oop oop_or_null(address addr); }; #endif // SHARE_OOPS_OOP_HPP