1 /*
   2  * Copyright (c) 2017, 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_VALUEKLASS_HPP
  26 #define SHARE_VM_OOPS_VALUEKLASS_HPP
  27 
  28 #include "oops/instanceKlass.hpp"
  29 #include "oops/method.hpp"
  30 #include "oops/oop.inline.hpp"
  31 
  32 // A ValueKlass is a specialized InstanceKlass for value types.
  33 
  34 
  35 class ValueKlass: public InstanceKlass {
  36   friend class VMStructs;
  37   friend class InstanceKlass;
  38 
  39 private:
  40 
  41   // Constructor
  42   ValueKlass(const ClassFileParser& parser)
  43     : InstanceKlass(parser, InstanceKlass::_misc_kind_value_type) { }
  44 
  45   // static Klass* array_klass_impl(InstanceKlass* this_k, bool or_null, int n, TRAPS);
  46  protected:
  47   // Returns the array class for the n'th dimension
  48   Klass* array_klass_impl(bool or_null, int n, TRAPS);
  49 
  50   // Returns the array class with this class as element type
  51   Klass* array_klass_impl(bool or_null, TRAPS);
  52 
  53  public:
  54   // Type testing
  55   bool is_value_slow() const        { return true; }
  56 
  57   // Casting from Klass*
  58   static ValueKlass* cast(Klass* k) {
  59     assert(k->is_value(), "cast to ValueKlass");
  60     return (ValueKlass*) k;
  61   }
  62 
  63   // Use this to return the size of an instance in heap words
  64   // Implementation is currently simple because all value types are allocated
  65   // in Java heap like Java objects.
  66   virtual int size_helper() const {
  67     return layout_helper_to_size_helper(layout_helper());
  68   }
  69 
  70   // minimum number of bytes occupied by nonstatic fields, HeapWord aligned or pow2
  71   int raw_value_byte_size() const;
  72 
  73   int first_field_offset() const;
  74 
  75   address data_for_oop(oop o) const {
  76     return ((address) (void*) o) + first_field_offset();
  77   }
  78 
  79    oop oop_for_data(address data) const {
  80     oop o = (oop) (data - first_field_offset());
  81     assert(o->is_oop(false), "Not an oop");
  82     return o;
  83   }
  84 
  85   // Query if h/w provides atomic load/store
  86   bool is_atomic();
  87 
  88   bool flatten_array();
  89 
  90   bool contains_oops() const { return nonstatic_oop_map_count() > 0; }
  91   int nonstatic_oop_count();
  92 
  93   // Prototype general store methods...
  94 
  95   // copy the fields, with no concern for GC barriers
  96   void raw_field_copy(void* src, void* dst, size_t raw_byte_size);
  97 
  98   void value_store(void* src, void* dst, bool dst_is_heap, bool dst_uninitialized) {
  99     value_store(src, dst, nonstatic_field_size() << LogBytesPerHeapOop, dst_is_heap, dst_uninitialized);
 100   }
 101 
 102   // store the value of this klass contained with src into dst, raw data ptr
 103   void value_store(void* src, void* dst, size_t raw_byte_size, bool dst_is_heap, bool dst_uninitialized);
 104 
 105 
 106   oop derive_value_type_copy(Handle src, InstanceKlass* target_klass, TRAPS);
 107 
 108   // GC support...
 109 
 110   // oop iterate raw value type data pointer (where oop_addr may not be an oop, but backing/array-element)
 111   template <bool nv, typename T, class OopClosureType>
 112   inline void oop_iterate_specialized(const address oop_addr, OopClosureType* closure);
 113 
 114   template <bool nv, typename T, class OopClosureType>
 115   inline void oop_iterate_specialized_bounded(const address oop_addr, OopClosureType* closure, void* lo, void* hi);
 116 
 117 };
 118 
 119 #endif /* SHARE_VM_OOPS_VALUEKLASS_HPP */