ExceptionChecker


1   /* Soot - a J*va Optimization Framework
2    * Copyright (C) 2004 Jennifer 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.base;
21  
22  import soot.*;
23  import soot.jimple.*;
24  import soot.util.*;
25  import java.util.*;
26  import soot.jimple.toolkits.scalar.*;
27  import soot.tagkit.*;
28  
29  public class ExceptionChecker extends BodyTransformer{
30  
31      FastHierarchy hierarchy;
32      ExceptionCheckerErrorReporter reporter;
33  
34      public ExceptionChecker(ExceptionCheckerErrorReporter r){
35          this.reporter = r;
36      }
37  
38      protected void internalTransform(Body b, String   phaseName, Map options){
39  
40          Iterator it = b.getUnits().iterator();
41          while (it.hasNext()){
42              Stmt s = (Stmt)it.next();
43              if (s instanceof ThrowStmt){
44                  ThrowStmt ts = (ThrowStmt)s;
45                  checkThrow(b, ts);
46              }
47              else if (s instanceof InvokeStmt){
48                  InvokeStmt is = (InvokeStmt)s;
49                  checkInvoke(b, is);
50              }
51              else if ((s instanceof AssignStmt) && (((AssignStmt)s).getRightOp() instanceof InvokeExpr)){
52                  InvokeExpr ie = (InvokeExpr)((AssignStmt)s).getRightOp();
53                  checkInvokeExpr(b, ie, s);
54              }
55          }
56      }
57  
58      protected void checkThrow(Body b, ThrowStmt ts){
59          if (isThrowDeclared(b, ((RefType)ts.getOp().getType()).getSootClass()) || isThrowFromCompiler(ts) || isExceptionCaught(b, ts, (RefType)ts.getOp().getType())) return;
60          if (reporter != null){
61              reporter.reportError(new ExceptionCheckerError(b.getMethod(), ((RefType)ts.getOp().getType()).getSootClass(), ts, (SourceLnPosTag)ts.getOpBox().getTag("SourceLnPosTag")));
62          }
63      }
64  
65      // does the method declare the throw if its a throw that needs declaring
66      // RuntimeException and subclasses do not need to be declared
67      // Error and subclasses do not need to be declared
68      protected boolean isThrowDeclared(Body b, SootClass throwClass){
69          if (hierarchy == null){
70              hierarchy = new FastHierarchy();
71          }
72  
73          // handles case when exception is RuntimeException or Error
74          if (throwClass.equals(Scene.v().getSootClass("java.lang.RuntimeException")) || throwClass.equals(Scene.v().getSootClass("java.lang.Error"))) return true;
75          // handles case when exception is a subclass of RuntimeException or Error
76          if (hierarchy.isSubclass(throwClass, Scene.v().getSootClass("java.lang.RuntimeException")) || hierarchy.isSubclass(throwClass, Scene.v().getSootClass("java.lang.Error"))) return true;
77  
78          // handles case when exact exception is thrown
79          if (b.getMethod().throwsException(throwClass)) return true;
80  
81          // handles case when a super type of the exception is thrown
82          Iterator it = b.getMethod().getExceptions().iterator();
83          while (it.hasNext()){
84              SootClass nextEx = (SootClass)it.next();
85              if (hierarchy.isSubclass(throwClass, nextEx)) return true;
86          }
87          return false;
88      }
89  
90      // is the throw created by the compiler
91      protected boolean isThrowFromCompiler(ThrowStmt ts){
92          if (ts.hasTag("ThrowCreatedByCompilerTag")) return true;
93          return false;
94      }
95  
96      // is the throw caught inside the method
97      protected boolean isExceptionCaught(Body b, Stmt s, RefType throwType){
98          if (hierarchy == null){
99              hierarchy = new FastHierarchy();
100         }
101         Iterator it = b.getTraps().iterator();
102         while (it.hasNext()){
103             Trap trap = (Trap)it.next();
104             if (trap.getException().getType().equals(throwType) || hierarchy.isSubclass(throwType.getSootClass(), ((RefType)trap.getException().getType()).getSootClass())){
105                 if (isThrowInStmtRange(b, (Stmt)trap.getBeginUnit(), (Stmt)trap.getEndUnit(), s)) return true;
106             }
107         }
108         return false;
109     }
110 
111     protected boolean isThrowInStmtRange(Body b, Stmt begin, Stmt end, Stmt s){
112         Iterator it = b.getUnits().iterator(begin, end);
113         while (it.hasNext()){
114             if (it.next().equals(s)) return true;
115         }
116         return false;
117     }
118 
119     protected void checkInvoke(Body b, InvokeStmt is){
120         checkInvokeExpr(b, is.getInvokeExpr(), is);
121     }
122 
123     // Given a method signature, see if it is declared in the given interface.
124     // If so, return the exceptions thrown by the declaration. Otherwise,
125     // Do the same thing recursively on superinterfaces and Object
126     // and return the intersection. This gives
127     // the maximal set of exceptions that could be declared to be thrown if the
128     // interface had declared the method. Returns null if no supertype declares
129     // the method.
130     private List getExceptionSpec(SootClass intrface,NumberedString sig) {
131         if(intrface.declaresMethod(sig)) return intrface.getMethod(sig).getExceptions();
132         List result=null;
133         SootClass obj=Scene.v().getSootClass("java.lang.Object");
134         if(obj.declaresMethod(sig)) result=new Vector(obj.getMethod(sig).getExceptions());
135         Iterator intrfacesit=intrface.getInterfaces().iterator();
136         while(intrfacesit.hasNext()) {
137             SootClass suprintr=(SootClass) intrfacesit.next();
138             List other=getExceptionSpec(suprintr,sig);
139             if(other!=null)
140                 if(result==null) result=other;
141                 else result.retainAll(other);
142         }
143         return result;
144     }
145 
146 
147     protected void checkInvokeExpr(Body b, InvokeExpr ie, Stmt s){
148         if(ie instanceof InstanceInvokeExpr &&
149            ((InstanceInvokeExpr) ie).getBase().getType() instanceof ArrayType &&
150            ie.getMethodRef().name().equals("clone") &&
151            ie.getMethodRef().parameterTypes().size()==0)
152             return;  // the call is to the clone() method of an array type, which
153                      // is defined not to throw any exceptions; if we left this to
154                      // normal resolution we'd get the method in Object which does
155                      // throw CloneNotSupportedException
156 
157         List exceptions=ie instanceof InterfaceInvokeExpr
158             // For an invokeinterface, there is no unique resolution for the
159             // method reference that will get the "correct" exception spec. We
160             // actually need to look at the intersection of all declarations of
161             // the method in supertypes.
162             ? getExceptionSpec(ie.getMethodRef().declaringClass(),
163                                ie.getMethodRef().getSubSignature())
164             // Otherwise, we just do normal resolution.
165             : ie.getMethod().getExceptions();
166         Iterator it = exceptions.iterator();
167         while (it.hasNext()){
168             SootClass sc = (SootClass)it.next();
169             if (isThrowDeclared(b, sc) || isExceptionCaught(b, s, sc.getType())) continue;
170             if (reporter != null){
171                 if (s instanceof InvokeStmt){
172                     reporter.reportError(new ExceptionCheckerError(b.getMethod(), sc, s, (SourceLnPosTag)s.getTag("SourceLnPosTag")));
173                 }
174                 else if (s instanceof AssignStmt){
175                     reporter.reportError(new ExceptionCheckerError(b.getMethod(), sc, s, (SourceLnPosTag)((AssignStmt)s).getRightOpBox().getTag("SourceLnPosTag")));
176                 }
177             }
178         }
179     }
180 }
181
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