[Fb-contrib-commit] SF.net SVN: fb-contrib:[1367] trunk/fb-contrib/src/com/mebigfatguy/ fbcontrib/detect/ContraVariantArrayAssignment.java

[<dbr...@us...>]

Revision: 1367
          http://fb-contrib.svn.sourceforge.net/fb-contrib/?rev=1367&view=rev
Author:   dbrosius
Date:     2009-10-15 03:33:46 +0000 (Thu, 15 Oct 2009)

Log Message:
-----------
add new detector CVAA - by Bhaskar Maddala

Added Paths:
-----------
    trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/ContraVariantArrayAssignment.java

Added: trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/ContraVariantArrayAssignment.java
===================================================================
--- trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/ContraVariantArrayAssignment.java	                        (rev 0)
+++ trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/ContraVariantArrayAssignment.java	2009-10-15 03:33:46 UTC (rev 1367)
@@ -0,0 +1,169 @@
+/*
+ * fb-contrib - Auxiliary detectors for Java programs
+ * Copyright (C) 2009 Bhaskar Maddala
+ * 
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+package com.mebigfatguy.fbcontrib.detect;
+
+import org.apache.bcel.classfile.Code;
+import org.apache.bcel.classfile.LocalVariable;
+import org.apache.bcel.classfile.LocalVariableTable;
+import org.apache.bcel.generic.ArrayType;
+import org.apache.bcel.generic.ObjectType;
+import org.apache.bcel.generic.Type;
+
+import com.mebigfatguy.fbcontrib.utils.RegisterUtils;
+
+import edu.umd.cs.findbugs.BugInstance;
+import edu.umd.cs.findbugs.BugReporter;
+import edu.umd.cs.findbugs.BytecodeScanningDetector;
+import edu.umd.cs.findbugs.OpcodeStack;
+
+/**
+ * Finds contravariant array assignments. Since arrays are mutable data structures, their use 
+ * must be restricted to covariant or invariant usage
+ * 
+ * <pre>
+ * class A {}
+ * class B extends A {}
+ * 
+ * B[] b = new B[2];
+ * A[] a = b;
+ * a[0] = new A(); // results in ArrayStoreException (Runtime)
+ * </pre>
+ *
+ */
+public class ContraVariantArrayAssignment extends BytecodeScanningDetector {
+	private final BugReporter bugReporter;
+	private final OpcodeStack stack;
+	
+    /**
+     * constructs a CVAA detector given the reporter to report bugs on.
+
+     * @param bugReporter the sync of bug reports
+     */
+	public ContraVariantArrayAssignment(final BugReporter bugReporter) {
+		this.bugReporter = bugReporter;
+		this.stack = new OpcodeStack();
+	}
+
+	/**
+	 * implements the visitor to pass through constructors and static initializers to the
+	 * byte code scanning code. These methods are not reported, but are used to build 
+	 * SourceLineAnnotations for fields, if accessed.
+	 * 
+	 * @param obj the context object of the currently parsed code attribute
+	 */
+	@Override
+	public void visitCode(Code obj) {
+		stack.resetForMethodEntry(this);
+		LocalVariableTable lvt = getMethod().getLocalVariableTable();
+		if(lvt != null) {
+			super.visitCode(obj);
+		}
+	}
+
+	@Override
+	public void sawOpcode(int seen) {
+		try{			
+			switch(seen){
+			case ASTORE:
+			case ASTORE_0:
+			case ASTORE_1:
+			case ASTORE_2:
+			case ASTORE_3:
+				if(stack.getStackDepth() > 0){
+					OpcodeStack.Item item = stack.getStackItem(0);					
+					String sourceSignature = item.getSignature();
+					LocalVariable lv = getMethod().getLocalVariableTable()
+					   .getLocalVariable(RegisterUtils.getAStoreReg(this, seen), getNextPC());
+					if(lv != null){
+						String targetSignature = lv.getSignature();
+						checkSignatures(sourceSignature, targetSignature);
+					}
+				}
+				break;
+			case PUTFIELD:
+			case PUTSTATIC:
+				if(stack.getStackDepth() > 0){
+					OpcodeStack.Item item = stack.getStackItem(0);					
+					String sourceSignature = item.getSignature();
+					String targetSignature = getSigConstantOperand();
+					checkSignatures(sourceSignature, targetSignature);
+				}
+				break;
+			case INVOKESTATIC:
+			case INVOKEVIRTUAL:
+			case INVOKEINTERFACE:
+			case INVOKESPECIAL:
+				if(stack.getStackDepth() > 0){
+					String signature = getSigConstantOperand();
+					checkMethodInvocation(signature);
+				}
+				break;			
+			}
+			super.sawOpcode(seen);			
+		}
+		finally{
+			stack.sawOpcode(this, seen);
+		}
+	}
+	
+	private boolean isArrayType(String signature){
+	    return Type.getType(signature) instanceof ArrayType;
+	}
+	
+	private boolean isObjectType(String signature){
+		return ((ArrayType)Type.getType(signature)).getBasicType() instanceof ObjectType;
+	}
+
+	private void checkSignatures(String sourceSignature, String targetSignature) {
+		try{
+			if(isArrayType(sourceSignature)) {
+				if(!isArrayType(targetSignature)){
+					bugReporter.reportBug(new BugInstance(this, "CVAA_CONTRAVARIANT_ARRAY_ASSIGNMENT", HIGH_PRIORITY)
+				    .addClass(this)
+				    .addMethod(this)
+				    .addSourceLine(this));
+				} else {
+					if(isObjectType(sourceSignature) && isObjectType(targetSignature)){
+						ObjectType sourceType = (ObjectType) ((ArrayType) Type.getType(sourceSignature)).getBasicType();
+						ObjectType targetType = (ObjectType) ((ArrayType) Type.getType(targetSignature)).getBasicType();
+						if(sourceType.subclassOf(targetType) && !targetType.subclassOf(sourceType)) {
+							bugReporter.reportBug(new BugInstance(this, "CVAA_CONTRAVARIANT_ARRAY_ASSIGNMENT", HIGH_PRIORITY)
+							    .addClass(this)
+							    .addMethod(this)
+							    .addSourceLine(this));
+						}
+					}
+				}
+			}			
+		}
+		catch(ClassNotFoundException cnfe) {
+			bugReporter.reportMissingClass(cnfe);
+		}
+	}
+
+	private void checkMethodInvocation(String signature) {
+		Type[] types = Type.getArgumentTypes(signature);
+		for(int i = 0; i < types.length; i++){
+			String targetSignature = types[i].getSignature();
+			OpcodeStack.Item item = stack.getStackItem(types.length - i - 1);
+			String sourceSignature = item.getSignature();
+		    checkSignatures(sourceSignature, targetSignature);			
+		}
+	}
+}


Property changes on: trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/ContraVariantArrayAssignment.java
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Added: svn:mime-type
   + text/plain
Added: svn:eol-style
   + native


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