1 /*
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  3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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  6  * under the terms of the GNU General Public License version 2 only, as
  7  * published by the Free Software Foundation.
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  9  * This code is distributed in the hope that it will be useful, but WITHOUT
 10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 12  * version 2 for more details (a copy is included in the LICENSE file that
 13  * accompanied this code).
 14  *
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 24 
 25 #ifndef SHARE_OOPS_ARRAYKLASS_HPP
 26 #define SHARE_OOPS_ARRAYKLASS_HPP
 27 
 28 #include "oops/klass.hpp"
 29 
 30 class fieldDescriptor;
 31 class klassVtable;
 32 
 33 // ArrayKlass is the abstract baseclass for all array classes
 34 
 35 class ArrayKlass: public Klass {
 36   friend class VMStructs;
 37  private:
 38   // If you add a new field that points to any metaspace object, you
 39   // must add this field to ArrayKlass::metaspace_pointers_do().
 40   int      _dimension;         // This is n'th-dimensional array.
 41   Klass* volatile _higher_dimension;  // Refers the (n+1)'th-dimensional array (if present).
 42   Klass* volatile _lower_dimension;   // Refers the (n-1)'th-dimensional array (if present).
 43 
 44  protected:
 45   Klass* _element_klass;            // The klass of the elements of this array type
 46                                     // The element type must be registered for both object arrays
 47                                     // (incl. object arrays with value type elements) and value type
 48                                     // arrays containing flattened value types. However, the element
 49                                     // type must not be registered for arrays of primitive types.
 50                                     // TODO: Update the class hierarchy so that element klass appears
 51                                     // only in array that contain non-primitive types.
 52   // Constructors
 53   // The constructor with the Symbol argument does the real array
 54   // initialization, the other is a dummy
 55   ArrayKlass(Symbol* name, KlassID id);
 56   ArrayKlass() { assert(DumpSharedSpaces || UseSharedSpaces, "only for cds"); }
 57 
 58   // Create array_name for element klass
 59   static Symbol* create_element_klass_array_name(Klass* element_klass, bool qdesc, TRAPS);
 60 
 61  public:
 62   // Instance variables
 63   virtual Klass* element_klass() const      { return _element_klass; }
 64   virtual void set_element_klass(Klass* k)  { _element_klass = k; }
 65 
 66   // Compiler/Interpreter offset
 67   static ByteSize element_klass_offset() { return in_ByteSize(offset_of(ArrayKlass, _element_klass)); }
 68 
 69   // Are loads and stores to this concrete array type atomic?
 70   // Note that Object[] is naturally atomic, but its subtypes may not be.
 71   virtual bool element_access_is_atomic() { return true; }
 72 
 73   // Testing operation
 74   DEBUG_ONLY(bool is_array_klass_slow() const { return true; })
 75 
 76   // Instance variables
 77   int dimension() const                 { return _dimension;      }
 78   void set_dimension(int dimension)     { _dimension = dimension; }
 79 
 80   Klass* higher_dimension() const     { return _higher_dimension; }
 81   inline Klass* higher_dimension_acquire() const; // load with acquire semantics
 82   void set_higher_dimension(Klass* k) { _higher_dimension = k; }
 83   inline void release_set_higher_dimension(Klass* k); // store with release semantics
 84 
 85   Klass* lower_dimension() const      { return _lower_dimension; }
 86   void set_lower_dimension(Klass* k)  { _lower_dimension = k; }
 87 
 88   // offset of first element, including any padding for the sake of alignment
 89   int  array_header_in_bytes() const    { return layout_helper_header_size(layout_helper()); }
 90   int  log2_element_size() const        { return layout_helper_log2_element_size(layout_helper()); }
 91   // type of elements (T_OBJECT for both oop arrays and array-arrays)
 92   BasicType element_type() const        { return layout_helper_element_type(layout_helper()); }
 93 
 94   virtual InstanceKlass* java_super() const;
 95 
 96   // Allocation
 97   // Sizes points to the first dimension of the array, subsequent dimensions
 98   // are always in higher memory.  The callers of these set that up.
 99   virtual oop multi_allocate(int rank, jint* sizes, TRAPS);
100   objArrayOop allocate_arrayArray(int n, int length, TRAPS);
101 
102   // find field according to JVM spec 5.4.3.2, returns the klass in which the field is defined
103   Klass* find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
104 
105   // Lookup operations
106   Method* uncached_lookup_method(const Symbol* name,
107                                  const Symbol* signature,
108                                  OverpassLookupMode overpass_mode,
109                                  PrivateLookupMode private_mode = PrivateLookupMode::find) const;
110 
111   static ArrayKlass* cast(Klass* k) {
112     return const_cast<ArrayKlass*>(cast(const_cast<const Klass*>(k)));
113   }
114 
115   static const ArrayKlass* cast(const Klass* k) {
116     assert(k->is_array_klass(), "cast to ArrayKlass");
117     return static_cast<const ArrayKlass*>(k);
118   }
119 
120   GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots,
121                                                   Array<InstanceKlass*>* transitive_interfaces);
122 
123   oop component_mirror() const;
124 
125   // Sizing
126   static int static_size(int header_size);
127 
128   virtual void metaspace_pointers_do(MetaspaceClosure* iter);
129 
130   // Iterators
131   void array_klasses_do(void f(Klass* k));
132   void array_klasses_do(void f(Klass* k, TRAPS), TRAPS);
133 
134   // Return a handle.
135   static void     complete_create_array_klass(ArrayKlass* k, Klass* super_klass, ModuleEntry* module, TRAPS);
136 
137 
138   // jvm support
139   jint compute_modifier_flags() const;
140 
141   // JVMTI support
142   jint jvmti_class_status() const;
143 
144   // CDS support - remove and restore oops from metadata. Oops are not shared.
145   virtual void remove_unshareable_info();
146   virtual void remove_java_mirror();
147   void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS);
148 
149   // Printing
150   void print_on(outputStream* st) const;
151   void print_value_on(outputStream* st) const;
152 
153   void oop_print_on(oop obj, outputStream* st);
154 
155   // Verification
156   void verify_on(outputStream* st);
157 
158   void oop_verify_on(oop obj, outputStream* st);
159 };
160 
161 #endif // SHARE_OOPS_ARRAYKLASS_HPP