1 /*
   2  * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   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  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_OOPS_ARRAYKLASS_HPP
  26 #define SHARE_VM_OOPS_ARRAYKLASS_HPP
  27 
  28 #include "memory/universe.hpp"
  29 #include "oops/klass.hpp"
  30 
  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   int      _dimension;         // This is n'th-dimensional array.
  39   Klass* volatile _higher_dimension;  // Refers the (n+1)'th-dimensional array (if present).
  40   Klass* volatile _lower_dimension;   // Refers the (n-1)'th-dimensional array (if present).
  41   int      _vtable_len;        // size of vtable for this klass
  42   oop      _component_mirror;  // component type, as a java/lang/Class
  43 
  44  protected:
  45   // Constructors
  46   // The constructor with the Symbol argument does the real array
  47   // initialization, the other is a dummy
  48   ArrayKlass(Symbol* name);
  49   ArrayKlass() { assert(DumpSharedSpaces || UseSharedSpaces, "only for cds"); }
  50 
  51  public:
  52   // Testing operation
  53   bool oop_is_array_slow() const { return true; }
  54 
  55   // Instance variables
  56   int dimension() const                 { return _dimension;      }
  57   void set_dimension(int dimension)     { _dimension = dimension; }
  58 
  59   Klass* higher_dimension() const     { return _higher_dimension; }
  60   void set_higher_dimension(Klass* k) { _higher_dimension = k; }
  61   Klass** adr_higher_dimension()      { return (Klass**)&this->_higher_dimension;}
  62 
  63   Klass* lower_dimension() const      { return _lower_dimension; }
  64   void set_lower_dimension(Klass* k)  { _lower_dimension = k; }
  65   Klass** adr_lower_dimension()       { return (Klass**)&this->_lower_dimension;}
  66 
  67   // offset of first element, including any padding for the sake of alignment
  68   int  array_header_in_bytes() const    { return layout_helper_header_size(layout_helper()); }
  69   int  log2_element_size() const        { return layout_helper_log2_element_size(layout_helper()); }
  70   // type of elements (T_OBJECT for both oop arrays and array-arrays)
  71   BasicType element_type() const        { return layout_helper_element_type(layout_helper()); }
  72 
  73   oop  component_mirror() const         { return _component_mirror; }
  74   void set_component_mirror(oop m)      { klass_oop_store(&_component_mirror, m); }
  75   oop* adr_component_mirror()           { return (oop*)&this->_component_mirror;}
  76 
  77   // Compiler/Interpreter offset
  78   static ByteSize component_mirror_offset() { return in_ByteSize(offset_of(ArrayKlass, _component_mirror)); }
  79 
  80   virtual Klass* java_super() const;//{ return SystemDictionary::Object_klass(); }
  81 
  82   // Allocation
  83   // Sizes points to the first dimension of the array, subsequent dimensions
  84   // are always in higher memory.  The callers of these set that up.
  85   virtual oop multi_allocate(int rank, jint* sizes, TRAPS);
  86   objArrayOop allocate_arrayArray(int n, int length, TRAPS);
  87 
  88   // Lookup operations
  89   Method* uncached_lookup_method(Symbol* name, Symbol* signature, MethodLookupMode mode) const;
  90 
  91   // Casting from Klass*
  92   static ArrayKlass* cast(Klass* k) {
  93     assert(k->oop_is_array(), "cast to ArrayKlass");
  94     return (ArrayKlass*) k;
  95   }
  96 
  97   GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots);
  98   bool compute_is_subtype_of(Klass* k);
  99 
 100   // Sizing
 101   static int header_size()                 { return sizeof(ArrayKlass)/HeapWordSize; }
 102   static int static_size(int header_size);
 103 
 104 #if INCLUDE_SERVICES
 105   virtual void collect_statistics(KlassSizeStats *sz) const {
 106     Klass::collect_statistics(sz);
 107     // Do nothing for now, but remember to modify if you add new
 108     // stuff to ArrayKlass.
 109   }
 110 #endif
 111 
 112   // Java vtable
 113   klassVtable* vtable() const;             // return new klassVtable
 114   int  vtable_length() const               { return _vtable_len; }
 115   static int base_vtable_length()          { return Universe::base_vtable_size(); }
 116   void set_vtable_length(int len)          { assert(len == base_vtable_length(), "bad length"); _vtable_len = len; }
 117  protected:
 118   inline intptr_t* start_of_vtable() const;
 119 
 120  public:
 121   // Iterators
 122   void array_klasses_do(void f(Klass* k));
 123   void array_klasses_do(void f(Klass* k, TRAPS), TRAPS);
 124 
 125   // GC support
 126   virtual void oops_do(OopClosure* cl);
 127 
 128   // Return a handle.
 129   static void     complete_create_array_klass(ArrayKlass* k, KlassHandle super_klass, TRAPS);
 130 
 131 
 132   // jvm support
 133   jint compute_modifier_flags(TRAPS) const;
 134 
 135   // JVMTI support
 136   jint jvmti_class_status() const;
 137 
 138   // CDS support - remove and restore oops from metadata. Oops are not shared.
 139   virtual void remove_unshareable_info();
 140   virtual void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS);
 141 
 142   // Printing
 143   void print_on(outputStream* st) const;
 144   void print_value_on(outputStream* st) const;
 145 
 146   void oop_print_on(oop obj, outputStream* st);
 147 
 148   // Verification
 149   void verify_on(outputStream* st);
 150 
 151   void oop_verify_on(oop obj, outputStream* st);
 152 };
 153 
 154 #endif // SHARE_VM_OOPS_ARRAYKLASS_HPP