1 cananian 1.1.2.1 // TinyClassFieldMap.java, created Fri Mar 15 19:21:30 2002 by cananian
2 cananian 1.1.2.1 // Copyright (C) 2000 C. Scott Ananian <cananian@alumni.princeton.edu>
3 cananian 1.1.2.1 // Licensed under the terms of the GNU GPL; see COPYING for details.
4 cananian 1.1.2.1 package harpoon.Backend.RuntimeTiny;
5 cananian 1.1.2.1
6 cananian 1.1.2.1 import harpoon.Backend.Analysis.ClassFieldMap;
7 cananian 1.1.2.1 import harpoon.ClassFile.HClass;
8 cananian 1.1.2.1 import harpoon.ClassFile.HField;
9 cananian 1.1.2.1
10 cananian 1.1.2.1 import java.util.ArrayList;
11 cananian 1.1.2.1 import java.util.Arrays;
12 cananian 1.1.2.1 import java.util.Collections;
13 cananian 1.1.2.1 import java.util.Comparator;
14 cananian 1.1.2.1 import java.util.HashMap;
15 cananian 1.1.2.1 import java.util.Iterator;
16 cananian 1.1.2.1 import java.util.List;
17 cananian 1.1.2.1 import java.util.Map;
18 cananian 1.1.2.1 /**
19 cananian 1.1.2.1 * <code>TinyClassFieldMap</code> is an extension of <code>ClassFieldMap</code>
20 cananian 1.1.2.1 * which lays out objects *attempting* to align them, but not forcing an
21 cananian 1.1.2.1 * alignment.
22 cananian 1.1.2.1 *
23 cananian 1.1.2.1 * @author C. Scott Ananian <cananian@alumni.princeton.edu>
24 cananian 1.3 * @version $Id: TinyClassFieldMap.java,v 1.3 2004/02/08 03:21:01 cananian Exp $
25 cananian 1.1.2.1 */
26 cananian 1.1.2.1 public abstract class TinyClassFieldMap extends ClassFieldMap {
27 cananian 1.1.2.2 final int first_alignment;
28 cananian 1.1.2.1
29 cananian 1.1.2.1 /** Creates a <code>TinyClassFieldMap</code>. */
30 cananian 1.1.2.2 public TinyClassFieldMap() { this(0); }
31 cananian 1.1.2.2 /** Creates a <code>TinyClassFieldMap</code>. */
32 cananian 1.1.2.2 public TinyClassFieldMap(int first_alignment) {
33 cananian 1.1.2.2 this.first_alignment = first_alignment;
34 cananian 1.1.2.2 }
35 cananian 1.1.2.1
36 cananian 1.1.2.1 /** Use this function to indicate a *preferred* but not *mandatory*
37 cananian 1.1.2.1 * alignment for the given field. We will "try hard" to honor this
38 cananian 1.1.2.1 * alignment, but not if it would mean increasing the object size. */
39 cananian 1.1.2.1 public int fieldPreferredAlignment(HField hf){ return fieldAlignment(hf); }
40 cananian 1.1.2.1
41 cananian 1.1.2.1 private final Map<HClass,HField[]> cache = new HashMap<HClass,HField[]>();
42 cananian 1.1.2.1 protected HField[] declaredFields(HClass hc) {
43 cananian 1.1.2.1 if (!cache.containsKey(hc)) {
44 cananian 1.1.2.1 // determine the alignment of the last field of the superclass.
45 cananian 1.1.2.2 int alignment=first_alignment;
46 cananian 1.1.2.1 HClass sc = hc.getSuperclass();
47 cananian 1.1.2.1 if (sc!=null) {
48 cananian 1.1.2.1 List<HField> l = fieldList(sc);
49 cananian 1.1.2.1 if (l.size()>0) {
50 cananian 1.1.2.1 HField lastfield = l.get(l.size()-1);
51 cananian 1.1.2.1 alignment = fieldOffset(lastfield)+fieldSize(lastfield);
52 cananian 1.1.2.1 }
53 cananian 1.1.2.1 }
54 cananian 1.1.2.1 // make list of non-static fields.
55 cananian 1.1.2.1 List<HField> l =
56 cananian 1.1.2.1 new ArrayList<HField>(Arrays.asList(hc.getDeclaredFields()));
57 cananian 1.1.2.1 for (Iterator<HField> it=l.iterator(); it.hasNext(); )
58 cananian 1.1.2.1 if (it.next().isStatic())
59 cananian 1.1.2.1 it.remove();
60 cananian 1.1.2.1 // sort declared fields by max(preferredalignment,alignment,size)
61 cananian 1.1.2.1 // (largest first)
62 cananian 1.1.2.1 Collections.sort(l, new Comparator<HField>() {
63 cananian 1.1.2.1 public int compare(HField hf1, HField hf2) {
64 cananian 1.1.2.1 int align1 = Math.max(fieldPreferredAlignment(hf1),
65 cananian 1.1.2.1 fieldAlignment(hf1));
66 cananian 1.1.2.1 int align2 = Math.max(fieldPreferredAlignment(hf2),
67 cananian 1.1.2.1 fieldAlignment(hf2));
68 cananian 1.1.2.1 return Math.max(fieldSize(hf2),align2)
69 cananian 1.1.2.1 - Math.max(fieldSize(hf1),align1);
70 cananian 1.1.2.1 }
71 cananian 1.1.2.1 });
72 cananian 1.1.2.1 // make our result list
73 cananian 1.1.2.1 List<HField> result = new ArrayList<HField>(l.size());
74 cananian 1.1.2.1 // while we have more fields to order:
75 cananian 1.1.2.1 while (!l.isEmpty()) {
76 cananian 1.1.2.1 HField selectedField = null;
77 cananian 1.1.2.1 // find the largest aligned *must-align* field.
78 cananian 1.1.2.1 // (a must-align field has fieldAlignment>1)
79 cananian 1.1.2.1 for (Iterator<HField> it=l.iterator();
80 cananian 1.1.2.1 selectedField==null && it.hasNext(); ) {
81 cananian 1.1.2.1 HField hf = it.next();
82 cananian 1.1.2.2 // hack to skip fields which cross the header boundary
83 cananian 1.1.2.2 if (alignment<0 && alignment+fieldSize(hf)>0) continue;
84 cananian 1.1.2.1 if (fieldAlignment(hf) > 1 &&
85 cananian 1.1.2.1 0 == (alignment % fieldAlignment(hf))) {
86 cananian 1.1.2.1 selectedField = hf;
87 cananian 1.1.2.1 it.remove();
88 cananian 1.1.2.1 }
89 cananian 1.1.2.1 }
90 cananian 1.1.2.1 // else, find the largest preferably-aligned field.
91 cananian 1.1.2.1 for (Iterator<HField> it=l.iterator();
92 cananian 1.1.2.1 selectedField==null && it.hasNext(); ) {
93 cananian 1.1.2.1 HField hf = it.next();
94 cananian 1.1.2.2 // hack to skip fields which cross the header boundary
95 cananian 1.1.2.2 if (alignment<0 && alignment+fieldSize(hf)>0) continue;
96 cananian 1.1.2.1 if (0 == (alignment % fieldPreferredAlignment(hf))) {
97 cananian 1.1.2.1 selectedField = hf;
98 cananian 1.1.2.1 it.remove();
99 cananian 1.1.2.1 }
100 cananian 1.1.2.1 }
101 cananian 1.1.2.1 // otherwise find the smallest unaligned field.
102 cananian 1.1.2.1 if (selectedField==null)
103 cananian 1.1.2.1 selectedField = l.remove(l.size()-1);
104 cananian 1.1.2.2 // hack to protect the header boundary.
105 cananian 1.1.2.2 if (alignment<0 && alignment+fieldSize(selectedField)>0)
106 cananian 1.1.2.2 alignment=0;
107 cananian 1.1.2.1 // okay, add the selected field to the result, update alignment
108 cananian 1.1.2.1 result.add(selectedField);
109 cananian 1.1.2.1 while (0 != (alignment % fieldAlignment(selectedField)))
110 cananian 1.1.2.1 alignment++;
111 cananian 1.1.2.1 alignment += fieldSize(selectedField);
112 cananian 1.1.2.1 }
113 cananian 1.1.2.1 // done.
114 cananian 1.1.2.1 cache.put(hc, result.toArray(new HField[result.size()]));
115 cananian 1.1.2.1 }
116 cananian 1.1.2.1 return cache.get(hc);
117 cananian 1.1.2.1 }
118 cananian 1.1.2.2 // XXX copied from superclass, but hacked to deal with first_alignment.
119 cananian 1.1.2.2 public int fieldOffset(HField hf) {
120 cananian 1.1.2.2 assert hf!=null && !hf.isStatic();
121 cananian 1.1.2.2 if (!cache2.containsKey(hf)) {
122 cananian 1.1.2.2 int offset=first_alignment;
123 cananian 1.3 for (HField nexthf : fieldList(hf.getDeclaringClass())) {
124 cananian 1.1.2.2 // hack to protect the header boundary
125 cananian 1.1.2.2 if (offset<0 && offset+fieldSize(nexthf)>0)
126 cananian 1.1.2.2 offset=0;
127 cananian 1.1.2.2 // end hack
128 cananian 1.1.2.2 int align = fieldAlignment(nexthf);
129 cananian 1.1.2.2 assert align>0;
130 cananian 1.1.2.2 if ((offset % align) != 0)
131 cananian 1.1.2.2 offset += align - (offset%align);
132 cananian 1.1.2.2 assert (offset % align) == 0;
133 cananian 1.1.2.2 if (!cache2.containsKey(nexthf))
134 cananian 1.1.2.2 cache2.put(nexthf, new Integer(offset));
135 cananian 1.1.2.2 offset+=fieldSize(nexthf);
136 cananian 1.1.2.2 }
137 cananian 1.1.2.2 }
138 cananian 1.1.2.2 assert cache2.containsKey(hf) : hf+" not in fieldList()";
139 cananian 1.1.2.2 return cache2.get(hf).intValue();
140 cananian 1.1.2.2 }
141 cananian 1.1.2.2 private final Map<HField,Integer> cache2 = new HashMap<HField,Integer>();
142 cananian 1.2 }