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1   /*
2    * Copyright (c) 2001, 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
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22   *
23   */
24  
25  package sun.jvm.hotspot.interpreter;
26  
27  import java.util.*;
28  import sun.jvm.hotspot.oops.*;
29  import sun.jvm.hotspot.utilities.*;
30  
31  class OopMapForCacheEntry extends GenerateOopMap {
32    private OopMapCacheEntry entry;
33    private int              bci;
34    private int              stackTop;
35  
36    OopMapForCacheEntry(Method method, int bci, OopMapCacheEntry entry) {
37      super(method);
38      this.entry = entry;
39      this.bci = bci;
40      this.stackTop = -1;
41    }
42  
43    public boolean reportResults() { return false; }
44  
45    public boolean possibleGCPoint(BytecodeStream bcs) {
46      return false; // We are not reporting any result. We call resultForBasicblock directly
47    }
48  
49    public void fillStackmapProlog(int nof_gc_points) {
50      // Do nothing
51    }
52  
53    public void fillStackmapEpilog() {
54      // Do nothing
55    }
56  
57    public void fillStackmapForOpcodes(BytecodeStream bcs,
58                                       CellTypeStateList vars,
59                                       CellTypeStateList stack,
60                                       int stackTop) {
61      // Only interested in one specific bci
62      if (bcs.bci() == bci) {
63        entry.setMask(vars, stack, stackTop);
64        this.stackTop = stackTop;
65      }
66    }
67  
68    public void fillInitVars(List/*<Integer>*/ initVars) {
69      // Do nothing
70    }
71  
72    public void computeMap() {
73      if (Assert.ASSERTS_ENABLED) {
74        Assert.that(!method().isNative(), "cannot compute oop map for native methods");
75      }
76      // First check if it is a method where the stackmap is always empty
77      if (method().getCodeSize() == 0 || method().getMaxLocals() + method().getMaxStack() == 0) {
78        entry.setEmptyMask();
79      } else {
80        super.computeMap();
81        resultForBasicblock(bci);
82      }
83    }
84  
85    public int size() {
86      if (Assert.ASSERTS_ENABLED) {
87        Assert.that(stackTop != -1, "computeMap must be called first");
88      }
89      return (int) ((method().isStatic() ? 0 : 1) + method().getMaxLocals() + stackTop);
90    }
91  }