fb-contrib-commit Mailing List for fb-contrib (Page 7)

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Revision: 1690
          http://fb-contrib.svn.sourceforge.net/fb-contrib/?rev=1690&view=rev
Author:   dbrosius
Date:     2011-06-15 05:04:52 +0000 (Wed, 15 Jun 2011)

Log Message:
-----------
initial implementation of STB, probably tons of FPs

Modified Paths:
--------------
    trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/StackedTryBlocks.java

Modified: trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/StackedTryBlocks.java
===================================================================

--- trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/StackedTryBlocks.java	2011-06-15 01:28:58 UTC (rev 1689)
+++ trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/StackedTryBlocks.java	2011-06-15 05:04:52 UTC (rev 1690)
@@ -2,16 +2,18 @@
 
 import java.util.ArrayList;
 import java.util.BitSet;
-import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
-import java.util.Map;
 
+import org.apache.bcel.Constants;
 import org.apache.bcel.classfile.Code;
 import org.apache.bcel.classfile.CodeException;
 
+import edu.umd.cs.findbugs.BugInstance;
 import edu.umd.cs.findbugs.BugReporter;
 import edu.umd.cs.findbugs.BytecodeScanningDetector;
+import edu.umd.cs.findbugs.OpcodeStack;
+import edu.umd.cs.findbugs.ba.ClassContext;
 
 /**
  * looks for two or more try catch blocks that are consecutive and catch the
@@ -22,41 +24,79 @@
 public class StackedTryBlocks extends BytecodeScanningDetector {
 
 	private final BugReporter bugReporter;
-	private Map<TryBlock, TryBlock> blocks;
+	private List<TryBlock> blocks;
 	private List<TryBlock> inBlocks;
+	private OpcodeStack stack;
 
 	public StackedTryBlocks(BugReporter bugReporter) {
 		this.bugReporter = bugReporter;
 	}
 
 	@Override
+	public void visitClassContext(ClassContext classContext) {
+		try {
+			stack = new OpcodeStack();
+			super.visitClassContext(classContext);
+		} finally {
+			stack = null;
+		}
+	}
+
+	@Override
 	public void visitCode(Code obj) {
 
 		try {
-			blocks = new HashMap<TryBlock, TryBlock>();
+			blocks = new ArrayList<TryBlock>();
 			inBlocks = new ArrayList<TryBlock>();
 
 			CodeException[] ces = obj.getExceptionTable();
 			for (CodeException ce : ces) {
 				TryBlock tb = new TryBlock(ce);
-				TryBlock block = blocks.get(tb);
-				if (block != null) {
-					block.addCatchType(ce);
+				int existingBlock = blocks.indexOf(tb);
+				if (existingBlock >= 0) {
+					tb = blocks.get(existingBlock);
+					tb.addCatchType(ce);
 				} else {
-					blocks.put(tb, tb);
+					blocks.add(tb);
 				}
 			}
 
-			Iterator<TryBlock> it = blocks.keySet().iterator();
-			int numSingleCatchBlocks = 0;
+			Iterator<TryBlock> it = blocks.iterator();
 			while (it.hasNext()) {
-				if (!it.next().hasMultipleHandlers()) {
-					numSingleCatchBlocks++;
+				if (it.next().hasMultipleHandlers()) {
+					it.remove();
 				}
 			}
 
-			if (numSingleCatchBlocks > 1) {
+			if (blocks.size() > 1) {
+				stack.resetForMethodEntry(this);
 				super.visitCode(obj);
+
+				if (blocks.size() > 1) {
+					TryBlock firstBlock = blocks.get(0);
+					for (int i = 1; i < blocks.size(); i++) {
+						TryBlock secondBlock = blocks.get(i);
+
+						if ((firstBlock.getCatchType() == secondBlock
+								.getCatchType())
+								&& (firstBlock.getThrowSignature()
+										.equals(secondBlock.getThrowSignature()))) {
+							bugReporter.reportBug(new BugInstance(this,
+									"STB_STACKED_TRY_BLOCKS", NORMAL_PRIORITY)
+									.addClass(this)
+									.addMethod(this)
+									.addSourceLineRange(this,
+											firstBlock.getStartPC(),
+											firstBlock.getEndHandlerPC())
+									.addSourceLineRange(this,
+											secondBlock.getStartPC(),
+											secondBlock.getEndHandlerPC()));
+
+						}
+
+						firstBlock = secondBlock;
+					}
+				}
 			}
 		} finally {
 			blocks = null;
@@ -67,31 +107,58 @@
 	@Override
 	public void sawOpcode(int seen) {
 
-		TryBlock block = findBlockWithStart();
-		if (block != null) {
-			inBlocks.add(block);
-		}
+		try {
+			int pc = getPC();
+			TryBlock block = findBlockWithStart(pc);
+			if (block != null) {
+				inBlocks.add(block);
+				block.setState(TryBlock.State.IN_TRY);
+			}
 
-		if (inBlocks.size() > 0) {
-			int nextPC = getNextPC();
-			TryBlock innerBlock = inBlocks.get(inBlocks.size() - 1);
-			if (nextPC == innerBlock.getHandlerPC()) {
-				if ((seen == GOTO) || (seen == GOTO_W)) {
-					innerBlock.setEndHandlerPC(getBranchTarget());
-				} else {
-					innerBlock.setEndHandlerPC(getCode().getLength());
+			if (inBlocks.size() > 0) {
+				TryBlock innerBlock = inBlocks.get(inBlocks.size() - 1);
+
+				int nextPC = getNextPC();
+				if (innerBlock.atHandlerPC(nextPC)) {
+					if ((seen == GOTO) || (seen == GOTO_W)) {
+						innerBlock.setEndHandlerPC(getBranchTarget());
+					} else {
+						inBlocks.remove(innerBlock);
+						blocks.remove(innerBlock);
+					}
+				} else if (innerBlock.atHandlerPC(pc)) {
+					innerBlock.setState(TryBlock.State.IN_CATCH);
+				} else if (innerBlock.atEndHandlerPC(pc)) {
+					inBlocks.remove(inBlocks.size() - 1);
+					innerBlock.setState(TryBlock.State.AFTER);
 				}
+
+				if (innerBlock.inCatch()) {
+					if (((seen >= Constants.IFEQ) && ((seen <= Constants.RET)))
+							|| ((seen >= Constants.IRETURN) && (seen <= Constants.RETURN))
+							|| (seen == GOTO_W)) {
+						blocks.remove(innerBlock);
+						inBlocks.remove(inBlocks.size() - 1);
+					} else if (seen == ATHROW) {
+						if (stack.getStackDepth() > 0) {
+							OpcodeStack.Item item = stack.getStackItem(0);
+							innerBlock.setThrowSignature(item.getSignature());
+						} else {
+							inBlocks.remove(inBlocks.size() - 1);
+							innerBlock.setState(TryBlock.State.AFTER);
+						}
+					}
+				}
 			}
+		} finally {
+			stack.sawOpcode(this, seen);
 		}
-
 	}
 
-	private TryBlock findBlockWithStart() {
+	private TryBlock findBlockWithStart(int pc) {
 
-		int pc = getPC();
-
-		for (TryBlock block : blocks.keySet()) {
-			if (block.getStartPC() == pc) {
+		for (TryBlock block : blocks) {
+			if (block.atStartPC(pc)) {
 				return block;
 			}
 		}
@@ -100,25 +167,41 @@
 	}
 
 	static class TryBlock {
+
+		public enum State {
+			BEFORE, IN_TRY, IN_CATCH, AFTER
+		};
+
 		int startPC;
 		int endPC;
 		int handlerPC;
 		int endHandlerPC;
 		BitSet catchTypes;
-		int throwType;
+		String throwSig;
+		State state;
 
 		public TryBlock(CodeException ce) {
 			startPC = ce.getStartPC();
 			endPC = ce.getEndPC();
 			handlerPC = ce.getHandlerPC();
+			endHandlerPC = -1;
 			catchTypes = new BitSet();
 			catchTypes.set(ce.getCatchType());
+			state = State.BEFORE;
 		}
 
 		public void addCatchType(CodeException ce) {
 			catchTypes.set(ce.getCatchType());
 		}
 
+		public void setState(State executionState) {
+			state = executionState;
+		}
+
+		public boolean inCatch() {
+			return state == State.IN_CATCH;
+		}
+
 		public boolean hasMultipleHandlers() {
 			int bit = catchTypes.nextSetBit(0);
 			return catchTypes.nextSetBit(bit + 1) >= 0;
@@ -128,18 +211,38 @@
 			endHandlerPC = end;
 		}
 
-		public void setThrowType(int type) {
-			throwType = type;
+		public void setThrowSignature(String sig) {
+			throwSig = sig;
 		}
 
+		public String getThrowSignature() {
+			return throwSig;
+		}
+
 		public int getStartPC() {
 			return startPC;
 		}
 
-		public int getHandlerPC() {
-			return handlerPC;
+		public int getEndHandlerPC() {
+			return endHandlerPC;
 		}
 
+		public boolean atStartPC(int pc) {
+			return startPC == pc;
+		}
+
+		public boolean atHandlerPC(int pc) {
+			return handlerPC == pc;
+		}
+
+		public boolean atEndHandlerPC(int pc) {
+			return (endHandlerPC >= 0) && (endHandlerPC == pc);
+		}
+
+		public int getCatchType() {
+			return catchTypes.nextSetBit(0);
+		}
+
 		@Override
 		public int hashCode() {
 			return startPC ^ endPC;
@@ -158,7 +261,7 @@
 		@Override
 		public String toString() {
 			return "{" + startPC + " -> " + endPC + "} (catch "
-					+ catchTypes.get(0) + ") {" + handlerPC + " -> "
+					+ catchTypes.nextSetBit(0) + ") {" + handlerPC + " -> "
 					+ endHandlerPC + "}";
 		}
 	}


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fb-contrib-commit Mailing List for fb-contrib (Page 7)

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