LocalTypeSet


1   /* Soot - a J*va Optimization Framework
2    * Copyright (C) 2003 Ondrej Lhotak
3    *
4    * This library is free software; you can redistribute it and/or
5    * modify it under the terms of the GNU Lesser General Public
6    * License as published by the Free Software Foundation; either
7    * version 2.1 of the License, or (at your option) any later version.
8    *
9    * This library is distributed in the hope that it will be useful,
10   * but WITHOUT ANY WARRANTY; without even the implied warranty of
11   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12   * Lesser General Public License for more details.
13   *
14   * You should have received a copy of the GNU Lesser General Public
15   * License along with this library; if not, write to the
16   * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17   * Boston, MA 02111-1307, USA.
18   */
19  
20  package soot.jimple.toolkits.pointer;
21  import soot.*;
22  import soot.util.*;
23  import java.util.*;
24  
25  /** Represents a set of (local,type) pairs using a bit-vector. */
26  class LocalTypeSet extends java.util.BitSet   {
27      protected List locals;
28      protected List types;
29  
30      /** Constructs a new empty set given a list of all locals and types that may
31       * ever be in the set. */
32      public LocalTypeSet( List locals, List types ) {
33      super( locals.size() * types.size() );
34      this.locals = locals;
35      this.types = types;
36      if( !Scene.v().hasFastHierarchy() ) {
37          Scene.v().setFastHierarchy( new FastHierarchy() );
38      }
39      }
40      /** Returns the number of the bit corresponding to the pair (l,t). */
41      protected int indexOf( Local l, RefType t ) {
42      if( locals.indexOf( l ) == -1 || types.indexOf( t ) == -1 ) {
43          throw new RuntimeException  ( "Invalid local or type in LocalTypeSet" );
44      }
45      return locals.indexOf( l ) * types.size() + types.indexOf( t );
46      }
47      /** Removes all pairs corresponding to local l from the set. */
48      public void killLocal( Local l ) {
49      int base = types.size() * locals.indexOf( l );
50      for( int i = 0; i < types.size(); i++ ) {
51          clear( i + base );
52      }
53      }
54      /** For each pair (from,t), adds a pair (to,t). */
55      public void localCopy( Local to, Local from ) {
56      int baseTo = types.size() * locals.indexOf( to );
57      int baseFrom = types.size() * locals.indexOf( from );
58      for( int i = 0; i < types.size(); i++ ) {
59          if( get( i+baseFrom ) ) {
60          set( i+baseTo );
61          } else {
62          clear( i+baseTo );
63          }
64      }
65      }
66      /** Empties the set. */
67      public void clearAllBits() {
68      for( int i = 0; i < types.size() * locals.size(); i++ ) {
69          clear( i );
70      }
71      }
72      /** Fills the set to contain all possible (local,type) pairs. */
73      public void setAllBits() {
74      for( int i = 0; i < types.size() * locals.size(); i++ ) {
75          set( i );
76      }
77      }
78      /** Adds to the set all pairs (l,type) where type is any supertype of t. */
79      public void localMustBeSubtypeOf( Local l, RefType t ) {
80      FastHierarchy fh = Scene.v().getFastHierarchy();
81      for( Iterator it = types.iterator(); it.hasNext(); ) {
82          RefType supertype = (RefType) it.next();
83          if( fh.canStoreType( t, supertype ) ) {
84          set( indexOf( l, supertype ) );
85          }
86      }
87      }
88  
89      public String   toString(){
90          StringBuffer   sb = new StringBuffer  ();
91          Iterator localsIt = locals.iterator();
92          while (localsIt.hasNext()){
93              Local l = (Local)localsIt.next();
94              Iterator typesIt = types.iterator();
95              while (typesIt.hasNext()){
96                  RefType t = (RefType)typesIt.next();
97                  int index = indexOf(l, t);
98                  //G.v().out.println("for: "+l+" and type: "+t+" at: "+index);
99                  if (get(index)) {
100                     sb.append("(("+l+","+t+") -> elim cast check) ");
101                 }
102             }
103             
104         }
105         return sb.toString(); 
106     }
107 }
108 
109
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