[Fb-contrib-commit] SF.net SVN: fb-contrib: [397] trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/FieldCouldBeLocal.java

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

Revision: 397
Author:   dbrosius
Date:     2006-04-04 08:22:32 -0700 (Tue, 04 Apr 2006)
ViewCVS:  http://svn.sourceforge.net/fb-contrib/?rev=397&view=rev

Log Message:
-----------
Fix for bug: [ 1462290 ] FCBL: infinite recursion? (stack overflow)

Convert FCBL's algorithm from recursive to iterative, to avoid stack overflow problems.

Modified Paths:
--------------
    trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/FieldCouldBeLocal.java
Modified: trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/FieldCouldBeLocal.java
===================================================================
--- trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/FieldCouldBeLocal.java	2006-04-04 14:38:03 UTC (rev 396)
+++ trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/FieldCouldBeLocal.java	2006-04-04 15:22:32 UTC (rev 397)
@@ -23,6 +23,7 @@
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
+import java.util.LinkedList;
 import java.util.Map;
 import java.util.Set;
 
@@ -184,65 +185,127 @@
 	 * @param uncheckedFields the list of fields to look for
 	 */
 	private void checkBlock(BasicBlock bb, Set<String> uncheckedFields) {
-		visitedBlocks.set(bb.getId());
-		InstructionIterator ii = bb.instructionIterator();
-		while (ii.hasNext()) {
-			InstructionHandle ih = ii.next();
-			Instruction ins = ih.getInstruction();
-			if (ins instanceof FieldInstruction) {
-				FieldInstruction fi = (FieldInstruction) ins;
-				String fieldName = fi.getFieldName(cpg);
-				uncheckedFields.remove(fieldName);
-				
-				if (ins instanceof GETFIELD) {
-					localizableFields.remove(fieldName);
-					if (localizableFields.size() == 0)
-						return;
-				} else {
-					FieldInfo finfo = localizableFields.get(fieldName);
-					if (finfo != null)
-						finfo.setSrcLineAnnotation(SourceLineAnnotation.fromVisitedInstruction(clsContext, this, ih.getPosition()));
-				}
-				if (uncheckedFields.size() == 0)
-					return;
-			} 
-		}
+		LinkedList<BlockState> toBeProcessed = new LinkedList<BlockState>();
+		toBeProcessed.add(new BlockState(bb, uncheckedFields));
 		
-		if (uncheckedFields.size() > 0) {
-			Iterator<Edge> oei = cfg.outgoingEdgeIterator(bb);
-			while (oei.hasNext()) {
-				Edge e = oei.next();
-				BasicBlock cb = e.getTarget();
-				if (!visitedBlocks.get(cb.getId())) {
-					Set<String> subCheckedFields = new HashSet<String>(uncheckedFields);
-					checkBlock(cb, subCheckedFields);
-					if (localizableFields.size() == 0)
+		while (toBeProcessed.size() > 0) {
+			if (localizableFields.size() == 0)
+				return;
+			BlockState bState = toBeProcessed.removeFirst();
+			bb = bState.getBasicBlock();
+			uncheckedFields = bState.getUncheckedFields();
+			
+			visitedBlocks.set(bb.getId());
+			InstructionIterator ii = bb.instructionIterator();
+			while (ii.hasNext()) {
+				InstructionHandle ih = ii.next();
+				Instruction ins = ih.getInstruction();
+				if (ins instanceof FieldInstruction) {
+					FieldInstruction fi = (FieldInstruction) ins;
+					String fieldName = fi.getFieldName(cpg);
+					uncheckedFields.remove(fieldName);
+					
+					if (ins instanceof GETFIELD) {
+						localizableFields.remove(fieldName);
+						if (localizableFields.size() == 0)
+							return;
+					} else {
+						FieldInfo finfo = localizableFields.get(fieldName);
+						if (finfo != null)
+							finfo.setSrcLineAnnotation(SourceLineAnnotation.fromVisitedInstruction(clsContext, this, ih.getPosition()));
+					}
+					if (uncheckedFields.size() == 0)
 						return;
+				} 
+			}
+			
+			if (uncheckedFields.size() > 0) {
+				Iterator<Edge> oei = cfg.outgoingEdgeIterator(bb);
+				while (oei.hasNext()) {
+					Edge e = oei.next();
+					BasicBlock cb = e.getTarget();
+					if (!visitedBlocks.get(cb.getId())) {
+						toBeProcessed.addLast(new BlockState(cb, uncheckedFields));
+					}
 				}
 			}
 		}
 	}
 	
+	/**
+	 * holds information about a field and it's first usage
+	 */
 	private static class FieldInfo {
 		private FieldAnnotation fieldAnnotation;
 		private SourceLineAnnotation srcLineAnnotation;
 		
+		/**
+		 * creates a FieldInfo from an annotation, and assumes no source line information
+		 * @param fa the field annotation for this field
+		 */
 		public FieldInfo(FieldAnnotation fa) {
 			fieldAnnotation = fa;
 			srcLineAnnotation = null;
 		}
 		
+		/**
+		 * set the source line annotation of first use for this field
+		 * @param sla the source line annotation
+		 */
 		public void setSrcLineAnnotation(SourceLineAnnotation sla) {
 			if (srcLineAnnotation == null)
 				srcLineAnnotation = sla;
 		}
 		
+		/**
+		 * get the field annotation for this field
+		 * @return the field annotation
+		 */
 		public FieldAnnotation getFieldAnnotation() {
 			return fieldAnnotation;
 		}
 		
+		/**
+		 * get the source line annotation for the first use of this field
+		 * @return the source line annotation
+		 */
 		public SourceLineAnnotation getSrcLineAnnotation() {
 			return srcLineAnnotation;
 		}
 	}
+	
+	/**
+	 * holds the parse state of the current basic block, and what fields are left to be checked
+	 */
+	private static class BlockState {
+		private BasicBlock basicBlock;
+		private Set<String> uncheckedFields;
+
+		/**
+		 * creates a BlockState consisting of the next basic block to parse, 
+		 * and what fields are to be checked
+		 * @param bb the basic block to parse
+		 * @param fields the fields to look for first use
+		 */
+		public BlockState(BasicBlock bb, Set<String> fields) {
+			basicBlock = bb;
+			uncheckedFields = new HashSet<String>(fields);
+		}
+		
+		/**
+		 * get the basic block to parse
+		 * @return the basic block
+		 */
+		public BasicBlock getBasicBlock() {
+			return basicBlock;
+		}
+		
+		/**
+		 * get the unchecked fields to look for
+		 * @return the unchecked fields
+		 */
+		public Set<String> getUncheckedFields() {
+			return uncheckedFields;
+		}
+	}
 }


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