ciConstantPoolCache.cpp revision 1472:c18cbe5936b8 
1/*
2 * Copyright (c) 1999, 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#include "incls/_precompiled.incl"
26#include "incls/_ciConstantPoolCache.cpp.incl"
27
28// ciConstantPoolCache
29//
30// This class caches indexed constant pool lookups.
31
32// ------------------------------------------------------------------
33// ciConstantPoolCache::ciConstantPoolCache
34ciConstantPoolCache::ciConstantPoolCache(Arena* arena,
35                                 int expected_size) {
36  _elements =
37    new (arena) GrowableArray<void*>(arena, expected_size, 0, 0);
38  _keys = new (arena) GrowableArray<intptr_t>(arena, expected_size, 0, 0);
39}
40
41// ------------------------------------------------------------------
42// ciConstantPoolCache::get
43//
44// Get the entry at some index
45void* ciConstantPoolCache::get(int index) {
46  ASSERT_IN_VM;
47  int pos = find(index);
48  if (pos >= _keys->length() ||
49      _keys->at(pos) != index) {
50    // This element is not present in the cache.
51    return NULL;
52  }
53  return _elements->at(pos);
54}
55
56// ------------------------------------------------------------------
57// ciConstantPoolCache::find
58//
59// Use binary search to find the position of this index in the cache.
60// If there is no entry in the cache corresponding to this oop, return
61// the position at which the index would be inserted.
62int ciConstantPoolCache::find(int key) {
63  int min = 0;
64  int max = _keys->length()-1;
65
66  while (max >= min) {
67    int mid = (max + min) / 2;
68    int value = _keys->at(mid);
69    if (value < key) {
70      min = mid + 1;
71    } else if (value > key) {
72      max = mid - 1;
73    } else {
74      return mid;
75    }
76  }
77  return min;
78}
79
80// ------------------------------------------------------------------
81// ciConstantPoolCache::insert
82//
83// Insert a ciObject into the table at some index.
84void ciConstantPoolCache::insert(int index, void* elem) {
85  int i;
86  int pos = find(index);
87  for (i = _keys->length()-1; i >= pos; i--) {
88    _keys->at_put_grow(i+1, _keys->at(i));
89    _elements->at_put_grow(i+1, _elements->at(i));
90  }
91  _keys->at_put_grow(pos, index);
92  _elements->at_put_grow(pos, elem);
93}
94
95// ------------------------------------------------------------------
96// ciConstantPoolCache::print
97//
98// Print debugging information about the cache.
99void ciConstantPoolCache::print() {
100  Unimplemented();
101}
102