1 /*
   2  * Copyright (c) 2000, 2019, 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_OOPS_ARRAY_HPP
  26 #define SHARE_OOPS_ARRAY_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "memory/metaspace.hpp"
  30 #include "runtime/atomic.hpp"
  31 #include "utilities/align.hpp"
  32 #include "utilities/macros.hpp"
  33 
  34 // Array for metadata allocation
  35 
  36 template <typename T>
  37 class Array: public MetaspaceObj {
  38   friend class MetadataFactory;
  39   friend class MetaspaceShared;
  40   friend class VMStructs;
  41   friend class JVMCIVMStructs;
  42   friend class MethodHandleCompiler;           // special case
  43   friend class WhiteBox;
  44 protected:
  45   int _length;                                 // the number of array elements
  46   T   _data[1];                                // the array memory
  47 
  48   void initialize(int length) {
  49     _length = length;
  50   }
  51 
  52  private:
  53   NONCOPYABLE(Array);
  54 
  55   void* operator new(size_t size, ClassLoaderData* loader_data, int length, TRAPS) throw() {
  56     size_t word_size = Array::size(length);
  57     return (void*) Metaspace::allocate(loader_data, word_size,
  58                                        MetaspaceObj::array_type(sizeof(T)), THREAD);
  59   }
  60 
  61   static size_t byte_sizeof(int length, size_t elm_byte_size) {
  62     return sizeof(Array<T>) + MAX2(length - 1, 0) * elm_byte_size;
  63   }
  64   static size_t byte_sizeof(int length) { return byte_sizeof(length, sizeof(T)); }
  65 
  66   // WhiteBox API helper.
  67   // Can't distinguish between array of length 0 and length 1,
  68   // will always return 0 in those cases.
  69   static int bytes_to_length(size_t bytes)       {
  70     assert(is_aligned(bytes, BytesPerWord), "Must be, for now");
  71 
  72     if (sizeof(Array<T>) >= bytes) {
  73       return 0;
  74     }
  75 
  76     size_t left = bytes - sizeof(Array<T>);
  77     assert(is_aligned(left, sizeof(T)), "Must be");
  78 
  79     size_t elements = left / sizeof(T);
  80     assert(elements <= (size_t)INT_MAX, "number of elements " SIZE_FORMAT "doesn't fit into an int.", elements);
  81 
  82     int length = (int)elements;
  83 
  84     assert((size_t)size(length) * BytesPerWord == (size_t)bytes,
  85            "Expected: " SIZE_FORMAT " got: " SIZE_FORMAT,
  86            bytes, (size_t)size(length) * BytesPerWord);
  87 
  88     return length;
  89   }
  90 
  91   explicit Array(int length) : _length(length) {
  92     assert(length >= 0, "illegal length");
  93   }
  94 
  95   Array(int length, T init) : _length(length) {
  96     assert(length >= 0, "illegal length");
  97     for (int i = 0; i < length; i++) {
  98       _data[i] = init;
  99     }
 100   }
 101 
 102  public:
 103 
 104   // standard operations
 105   int  length() const                 { return _length; }
 106   T* data()                           { return _data; }
 107   bool is_empty() const               { return length() == 0; }
 108 
 109   int index_of(const T& x) const {
 110     int i = length();
 111     while (i-- > 0 && _data[i] != x) ;
 112 
 113     return i;
 114   }
 115 
 116   // sort the array.
 117   bool contains(const T& x) const      { return index_of(x) >= 0; }
 118 
 119   T    at(int i) const                 { assert(i >= 0 && i< _length, "oob: 0 <= %d < %d", i, _length); return _data[i]; }
 120   void at_put(const int i, const T& x) { assert(i >= 0 && i< _length, "oob: 0 <= %d < %d", i, _length); _data[i] = x; }
 121   T*   adr_at(const int i)             { assert(i >= 0 && i< _length, "oob: 0 <= %d < %d", i, _length); return &_data[i]; }
 122   int  find(const T& x)                { return index_of(x); }
 123 
 124   T at_acquire(const int i)            { return Atomic::load_acquire(adr_at(i)); }
 125   void release_at_put(int i, T x)      { Atomic::release_store(adr_at(i), x); }
 126 
 127   static int size(int length) {
 128     size_t bytes = align_up(byte_sizeof(length), BytesPerWord);
 129     size_t words = bytes / BytesPerWord;
 130 
 131     assert(words <= INT_MAX, "Overflow: " SIZE_FORMAT, words);
 132 
 133     return (int)words;
 134   }
 135   int size() {
 136     return size(_length);
 137   }
 138 
 139   static int length_offset_in_bytes() { return (int) (offset_of(Array<T>, _length)); }
 140   // Note, this offset don't have to be wordSize aligned.
 141   static int base_offset_in_bytes() { return (int) (offset_of(Array<T>, _data)); };
 142 
 143   // FIXME: How to handle this?
 144   void print_value_on(outputStream* st) const {
 145     st->print("Array<T>(" INTPTR_FORMAT ")", p2i(this));
 146   }
 147 
 148 #ifndef PRODUCT
 149   void print(outputStream* st) {
 150      for (int i = 0; i< _length; i++) {
 151        st->print_cr("%d: " INTPTR_FORMAT, i, (intptr_t)at(i));
 152      }
 153   }
 154   void print() { print(tty); }
 155 #endif // PRODUCT
 156 };
 157 
 158 
 159 #endif // SHARE_OOPS_ARRAY_HPP