[Fb-contrib-commit] SF.net SVN: fb-contrib: [694] trunk/fb-contrib

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

Revision: 694
          http://svn.sourceforge.net/fb-contrib/?rev=694&view=rev
Author:   dbrosius
Date:     2006-11-19 17:31:22 -0800 (Sun, 19 Nov 2006)

Log Message:
-----------
add assignment stutter checking to SPP

Modified Paths:
--------------
    trunk/fb-contrib/etc/findbugs.xml
    trunk/fb-contrib/etc/messages.xml
    trunk/fb-contrib/samples/SPP_Sample.java
    trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/SillynessPotPourri.java

Modified: trunk/fb-contrib/etc/findbugs.xml
===================================================================
--- trunk/fb-contrib/etc/findbugs.xml	2006-11-19 05:52:18 UTC (rev 693)
+++ trunk/fb-contrib/etc/findbugs.xml	2006-11-20 01:31:22 UTC (rev 694)
@@ -256,7 +256,7 @@
 			
 	<Detector class="com.mebigfatguy.fbcontrib.detect.SillynessPotPourri"
 			speed="fast"
-			reports="SPP_NEGATIVE_BITSET_ITEM,SPP_INTERN_ON_CONSTANT,SPP_NO_CHAR_SB_CTOR,SPP_USE_MATH_CONSTANT"/>
+			reports="SPP_NEGATIVE_BITSET_ITEM,SPP_INTERN_ON_CONSTANT,SPP_NO_CHAR_SB_CTOR,SPP_USE_MATH_CONSTANT,SPP_STUTTERED_ASSIGNMENT"/>
 			
    	<!-- BugPattern -->
 	
@@ -327,5 +327,6 @@
 	<BugPattern abbrev="SPP" type="SPP_INTERN_ON_CONSTANT" category="CORRECTNESS" experimental="true" />
 	<BugPattern abbrev="SPP" type="SPP_NO_CHAR_SB_CTOR" category="CORRECTNESS" experimental="true" />
 	<BugPattern abbrev="SPP" type="SPP_USE_MATH_CONSTANT" category="CORRECTNESS" experimental="true" />
+	<BugPattern abbrev="SPP" type="SPP_STUTTERED_ASSIGNMENT" category="CORRECTNESS" experimental="true" />
 
 </FindbugsPlugin>
\ No newline at end of file

Modified: trunk/fb-contrib/etc/messages.xml
===================================================================
--- trunk/fb-contrib/etc/messages.xml	2006-11-19 05:52:18 UTC (rev 693)
+++ trunk/fb-contrib/etc/messages.xml	2006-11-20 01:31:22 UTC (rev 694)
@@ -1562,6 +1562,18 @@
 		</Details>
 	</BugPattern>
 	
+	<BugPattern type="SPP_STUTTERED_ASSIGNMENT">
+		<ShortDescription>Method assigns a value to a local twice in a row</ShortDescription>
+		<LongDescription>Method {1} assigns a value to a local twice in a row</LongDescription>
+		<Details>
+			<![CDATA[
+			<p>This method assigns a value twice in a row in a stuttered way such as
+			<code>a = a = 5;</code> This is most probably a cut and paste error where the duplicate
+			assignment can be removed.</p>
+			]]>
+		</Details>
+	</BugPattern>
+	
 	<!-- BugCode -->
 	
 	<BugCode abbrev="ISB">Inefficient String Buffering</BugCode>

Modified: trunk/fb-contrib/samples/SPP_Sample.java
===================================================================
--- trunk/fb-contrib/samples/SPP_Sample.java	2006-11-19 05:52:18 UTC (rev 693)
+++ trunk/fb-contrib/samples/SPP_Sample.java	2006-11-20 01:31:22 UTC (rev 694)
@@ -26,4 +26,9 @@
 	{
 		return pi * radius * radius;
 	}
+	
+	public void testStutter(String s)
+	{
+		String a = a = s;
+	}
 }

Modified: trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/SillynessPotPourri.java
===================================================================
--- trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/SillynessPotPourri.java	2006-11-19 05:52:18 UTC (rev 693)
+++ trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/SillynessPotPourri.java	2006-11-20 01:31:22 UTC (rev 694)
@@ -21,6 +21,8 @@
 import org.apache.bcel.classfile.Code;
 import org.apache.bcel.classfile.ConstantDouble;
 
+import com.mebigfatguy.fbcontrib.utils.RegisterUtils;
+
 import edu.umd.cs.findbugs.BugInstance;
 import edu.umd.cs.findbugs.BugReporter;
 import edu.umd.cs.findbugs.BytecodeScanningDetector;
@@ -35,6 +37,7 @@
 	private BugReporter bugReporter;
 	private OpcodeStack stack;
 	private int lastOpcode;
+	private int lastReg;
 	
 	/**
      * constructs a SPP detector given the reporter to report bugs on
@@ -61,6 +64,7 @@
 	public void visitCode(Code obj) {
 		stack.resetForMethodEntry(this);
 		lastOpcode = -1;
+		lastReg = -1;
 		super.visitCode(obj);
 	}
 	
@@ -70,6 +74,7 @@
 	 * @param seen the opcode of the currently parsed instruction
 	 */
 	public void sawOpcode(int seen) {
+		int reg = -1;
 		try {
 			stack.mergeJumps(this);
 			
@@ -88,6 +93,16 @@
 								   .addSourceLine(this));
 					}
 				}
+			} else if (((seen >= ASTORE_0) && (seen < ASTORE_3)) || (seen == ASTORE)) {
+				reg = RegisterUtils.getAStoreReg(this, seen);
+				if (seen == lastOpcode) {
+					if (reg == lastReg) {
+						bugReporter.reportBug(new BugInstance(this, "SPP_STUTTERED_ASSIGNMENT", NORMAL_PRIORITY)
+								   .addClass(this)
+								   .addMethod(this)
+								   .addSourceLine(this));
+					}
+				}
 			} else if (seen == INVOKEVIRTUAL) {
 				String className = getClassConstantOperand();
 				String methodName = getNameConstantOperand();
@@ -157,6 +172,7 @@
 		} finally {
 			stack.sawOpcode(this, seen);
 			lastOpcode = seen;
+			lastReg = reg;
 		}
 	}
 }


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