*** empty log message ***

git-svn-id: https://svn.code.sf.net/p/jode/code/trunk@40 379699f6-c40d-0410-875b-85095c16579e

jode/jode/Decompiler.java

@@ -25,7 +25,9 @@ public class Decompiler {
     public static boolean isVerbose = false;
     public static boolean isDebugging = false;
     public static boolean isTypeDebugging = false;
+    public static boolean isFlowDebugging = false;
     public static boolean showLVT = false;
+    public static boolean doChecks = false;
 
     public static void main(String[] params) {
         JodeEnvironment env = new JodeEnvironment();
@@ -36,8 +38,12 @@ public class Decompiler {
                 isDebugging = true;
             else if (params[i].equals("-type"))
                 isTypeDebugging = true;
+            else if (params[i].equals("-flow"))
+                isFlowDebugging = true;
             else if (params[i].equals("-lvt"))
                 showLVT = true;
+            else if (params[i].equals("-check"))
+                doChecks = true;
             else
                 env.doClass(params[i]);
         }

jode/jode/decompiler/CodeAnalyzer.java

@@ -154,9 +154,21 @@ public class CodeAnalyzer implements Analyzer, Constants {
         /* XXX optimize */
         Stack todo = new Stack();
         FlowBlock flow = methodHeader;
+        try {
+            jode.TabbedPrintWriter writer = null;
+            if (Decompiler.isFlowDebugging) {
+                writer = new jode.TabbedPrintWriter(System.err, "    ");
+            }
         analyzation:
             while (true) {
 
+                if (Decompiler.isFlowDebugging) {
+                    writer.println("before Transformation: ");
+                    writer.tab();
+                    flow.dumpSource(writer);
+                    writer.untab();
+                }
+
                 /* First do some non flow transformations. */
                 int i=0;
                 while (i < exprTrafos.length) {
@@ -166,7 +178,22 @@ public class CodeAnalyzer implements Analyzer, Constants {
                         i++;
                 }
             
+                if (Decompiler.isFlowDebugging) {
+                    writer.println("after Transformation: ");
+                    writer.tab();
+                    flow.dumpSource(writer);
+                    writer.untab();
+                }
+
                 if (flow.doT2(todo)) {
+
+                    if (Decompiler.isFlowDebugging) {
+                        writer.println("after T2: ");
+                        writer.tab();
+                        flow.dumpSource(writer);
+                        writer.untab();
+                    }
+
                     /* T2 transformation succeeded.  This may
                      * make another T1 analysis in the previous
                      * block possible.  
@@ -176,10 +203,36 @@ public class CodeAnalyzer implements Analyzer, Constants {
                 }
 
                 FlowBlock succ = flow.getSuccessor();
-            while (succ != null && !flow.doT1(succ)) {
+                while (true) {
+                    if (succ == null) {
+                        /* the Block has no successor where t1 is applicable.
+                         *
+                         * If everything is okay the stack should be empty now,
+                         * and the program is transformed correctly.
+                         */
+                        if (todo.isEmpty())
+                            break analyzation;
                             
-                /* T1 transformation failed. */
-                if (!todo.contains(succ) && succ != flow) {
+                        /* Otherwise pop the last flow block from stack and
+                         * try another successor.
+                         */
+                        succ = flow;
+                        flow = (FlowBlock) todo.pop();
+                    } else if (flow.doT1(succ)) {
+                        /* T1 transformation succeeded. */
+
+                        if (Decompiler.isFlowDebugging) {
+                            writer.println("after T1: ");
+                            writer.tab();
+                            flow.dumpSource(writer);
+                            writer.untab();
+                        }
+
+                        if (Decompiler.isVerbose)
+                            System.err.print(".");
+
+                        continue analyzation;
+                    } else if (!todo.contains(succ) && succ != flow) {
                         /* succ wasn't tried before, succeed with
                          * successor and put flow on the stack.  
                          */
@@ -192,24 +245,8 @@ public class CodeAnalyzer implements Analyzer, Constants {
                      */
                     succ = flow.getSuccessor(succ);
                 }
-            if (succ == null) {
-                /* the Block has no successor where t1 is applicable.
-                 *
-                 * If everything is okay the stack should be empty now,
-                 * and the program is transformed correctly.
-                 *
-                 * Otherwise flow transformation didn't succeeded.
-                 */
-//                 System.err.println("breaking analyzation; flow: "
-//                                    + flow.getLabel());
-                while (!todo.isEmpty()) {
-                    System.err.println("on Stack: "
-                                       + ((FlowBlock)todo.pop()).getLabel());
-                }
-                break analyzation;
             }
-	    if (Decompiler.isVerbose)
-		System.err.print(".");
+        } catch (java.io.IOException ioex) {
         }
     }
 

jode/jode/decompiler/LocalInfo.java

@@ -37,7 +37,6 @@ public class LocalInfo {
     private Identifier name;
     private Type type;
     private LocalInfo shadow;
-    private jode.flow.StructuredBlock defining;
 
     /* The current implementation may use very much stack.  This
      * should be changed someday.
@@ -156,14 +155,6 @@ public class LocalInfo {
         return this.type;
     }
 
-    public jode.flow.StructuredBlock getDefining() {
-        return getLocalInfo().defining;
-    }
-
-    public void setDefining(jode.flow.StructuredBlock structuredBlock) {
-        getLocalInfo().defining = structuredBlock;
-    }
-
     public boolean isShadow() {
 	return (shadow != null);
     }

jode/jode/expr/ArrayLoadOperator.java

@@ -40,15 +40,12 @@ public class ArrayLoadOperator extends SimpleOperator {
 
     /**
      * Sets the return type of this operator.
-     * @return true if the operand types changed
      */
-    public boolean setType(Type type) {
+    public void setType(Type type) {
         if (type != this.type) {
             super.setType(type);
             operandTypes[0] = Type.tArray(type);
-            return true;
         }
-        return false;
     }
 
     public void setOperandType(Type[] t) {

jode/jode/expr/AssignOperator.java

@@ -50,12 +50,10 @@ public class AssignOperator extends Operator {
 
     /**
      * Sets the return type of this operator.
-     * @return true if the operand types changed
      */
-    public boolean setType(Type type) {
-        boolean result = store.setLValueType(type);
+    public void setType(Type type) {
+        store.setLValueType(type);
         super.setType(store.getLValueType());
-        return result;
     }
 
     /**

jode/jode/expr/BinaryOperator.java

@@ -74,15 +74,9 @@ public class BinaryOperator extends Operator {
 
     /**
      * Sets the return type of this operator.
-     * @return true if the operand types changed
      */
-    public boolean setType(Type newType) {
-        operandType = MyType.intersection(operandType, newType);
-        if (type != operandType) {
-            type = operandType;
-            return true;
-        }
-        return false;
+    public void setType(Type newType) {
+        type = operandType = MyType.intersection(operandType, newType);
     }
 
     public boolean equals(Object o) {

jode/jode/expr/CompareBinaryOperator.java

@@ -44,6 +44,13 @@ public class CompareBinaryOperator extends SimpleOperator {
         return getPriority()+i;
     }
 
+    public void setOperandType(Type[] inputTypes) {
+        super.setOperandType(inputTypes);
+        Type operandType = 
+            MyType.intersection(operandTypes[0],operandTypes[1]);
+        operandTypes[0] = operandTypes[1] = operandType;
+    }
+
     public boolean equals(Object o) {
 	return (o instanceof CompareBinaryOperator) &&
 	    ((CompareBinaryOperator)o).operator == operator;

jode/jode/expr/Expression.java

@@ -134,7 +134,9 @@ public class Expression extends Instruction {
         if (operator.getPriority() < minPriority) {
             result = "("+result+")";
         }
-        if (operator.getType() == MyType.tError)
+        if (Decompiler.isTypeDebugging) 
+            result = "(("+operator.getType()+")"+result+")";
+        else if (operator.getType() == MyType.tError)
             result = "(/*type error */" + result+")";
         return result;
     }

jode/jode/expr/IfThenElseOperator.java

@@ -58,14 +58,12 @@ public class IfThenElseOperator extends SimpleOperator {
      * Sets the return type of this operator.
      * @return true if the operand types changed
      */
-    public boolean setType(Type newType) {
+    public void setType(Type newType) {
         Type operandType = 
             MyType.intersection(operandTypes[1], newType);
         if (type != operandType) {
             type = operandTypes[1] = operandTypes[2] = operandType;
-            return true;
         }
-        return false;
     }
 
     public boolean equals(Object o) {

jode/jode/expr/Instruction.java

@@ -31,6 +31,10 @@ public abstract class Instruction {
         return type;
     }
 
+    public void setType(Type newType) {
+        this.type = newType;
+    }
+
     public Instruction simplify() {
         return this;
     }

jode/jode/expr/LocalLoadOperator.java

@@ -43,7 +43,7 @@ implements LocalVarOperator {
 //     }
 
     public LocalInfo getLocalInfo() {
-	return local;
+	return local.getLocalInfo();
     }
 
     public Type getType() {
@@ -51,9 +51,9 @@ implements LocalVarOperator {
 	return local.getType();
     }
 
-    public boolean setType(Type type) {
+    public void setType(Type type) {
 // 	System.err.println("LocalLoad.setType of "+local.getName()+": "+local.getType());
-	return super.setType(local.setType(type));
+	super.setType(local.setType(type));
     }
 
 //     public int getSlot() {

jode/jode/expr/LocalStoreOperator.java

@@ -37,13 +37,8 @@ implements LocalVarOperator {
         return true;
     }
 
-//     public void setLocalInfo(LocalInfo local) {
-//         local.setType(lvalueType);
-// 	this.local = local;
-//     }
-
     public LocalInfo getLocalInfo() {
-	return local;
+	return local.getLocalInfo();
     }
 
     public Type getLValueType() {

jode/jode/expr/Operator.java

@@ -68,11 +68,9 @@ public abstract class Operator extends Instruction {
 
     /**
      * Sets the return type of this operator.
-     * @return true if the operand types changed
      */
-    public boolean setType(Type type) {
+    public void setType(Type type) {
         this.type = type;
-        return false;
     }
 
     public String getOperatorString() {

jode/jode/expr/PostFixOperator.java

@@ -53,12 +53,10 @@ public class PostFixOperator extends Operator {
 
     /**
      * Sets the return type of this operator.
-     * @return true if the operand types changed
      */
-    public boolean setType(Type type) {
-        boolean result = store.setLValueType(type);
+    public void setType(Type type) {
+        store.setLValueType(type);
         super.setType(store.getLValueType());
-        return result;
     }
 
     public void setOperandType(Type[] inputTypes) {

jode/jode/expr/UnaryOperator.java

@@ -35,16 +35,11 @@ public class UnaryOperator extends SimpleOperator {
 
     /**
      * Sets the return type of this operator.
-     * @return true if the operand types changed
      */
-    public boolean setType(Type type) {
+    public void setType(Type type) {
         super.setType(type);
         Type newOpType = MyType.intersection(type, operandTypes[0]);
-        if (newOpType != operandTypes[0]) {
         operandTypes[0] = newOpType;
-            return true;
-        }
-        return false;
     }
 
     public boolean equals(Object o) {

jode/jode/flow/BreakBlock.java

@@ -63,6 +63,14 @@ public class BreakBlock extends StructuredBlock {
         return breaksBlock.getNextFlowBlock();
     }
 
+    /**
+     * Tells if this block needs braces when used in a if or while block.
+     * @return true if this block should be sorrounded by braces.
+     */
+    public boolean needsBraces() {
+        return false;
+    }
+
     public void dumpInstruction(TabbedPrintWriter writer) 
 	throws java.io.IOException
     {

jode/jode/flow/CatchBlock.java

@@ -85,8 +85,7 @@ public class CatchBlock extends StructuredBlock {
                      ? new EmptyBlock()
                      : catchBlock.getSubBlocks()[1]);
 
-                if (catchBlock.jump != null)
-                    newCatchBlock.moveJump(catchBlock);
+		newCatchBlock.moveJump(catchBlock.jump);
                 catchBlock = newCatchBlock;
             }
         }

jode/jode/flow/ConditionalBlock.java

@@ -34,10 +34,9 @@ public class ConditionalBlock extends InstructionContainer {
      */
     public ConditionalBlock(Instruction cond, Jump condJump, Jump elseJump) {
         super(cond, elseJump);
-        if (cond instanceof LocalVarOperator) {
-            LocalVarOperator varOp = (LocalVarOperator) cond;
-            condJump.out.addElement(varOp.getLocalInfo());
-        }
+        /* cond is a CompareBinary or CompareUnary operator, so no
+         * check for LocalVarOperator (for condJump) is needed here.  
+         */
         trueBlock = new EmptyBlock(condJump);
         trueBlock.outer = this;
     }

jode/jode/flow/EmptyBlock.java

@@ -31,6 +31,23 @@ public class EmptyBlock extends StructuredBlock {
         setJump(jump);
     }
 
+    /**
+     * Appends a block to this block.
+     * @return the new combined block.
+     */
+    public StructuredBlock appendBlock(StructuredBlock block) {
+	if (outer instanceof ConditionalBlock) {
+	    IfThenElseBlock ifBlock = 
+		new IfThenElseBlock(((ConditionalBlock)outer).
+				    getInstruction());
+	    ifBlock.replace(outer, this);
+	    ifBlock.moveJump(outer.jump);
+	    ifBlock.setThenBlock(this);
+	}
+	block.replace(this, null);
+	return block;
+    }
+
     public void dumpInstruction(TabbedPrintWriter writer) 
 	throws java.io.IOException
     {

jode/jode/flow/FlowBlock.java

@@ -131,7 +131,7 @@ public class FlowBlock {
             newBlock.setCatchBlock(catchBlock);
             if (sequBlock.jump != null) {
                 if (newBlock.catchBlock.jump == null)
-                    newBlock.catchBlock.moveJump(sequBlock);
+                    newBlock.catchBlock.moveJump(sequBlock.jump);
                 else
                     sequBlock.removeJump();
             }
@@ -156,156 +156,79 @@ public class FlowBlock {
             if (jump == null || jump.destination != successor)
                 continue next_jump;
 
-        same_jump: while(true) {
-            /* if the jump is the jump of the appendBlock, skip it.
-             */
-            if (jump.prev == null || jump.prev == appendBlock)
-                continue next_jump;
+        while(jump != null) {
 
-            /* Note: jump.prev.outer != null, since appendBlock is
-             * an outer block of jump.prev
-             */
+            if (jump.prev instanceof EmptyBlock
+		&& jump.prev.outer != null
+                && jump.prev.outer instanceof ConditionalBlock
+		&& jump.prev.outer.jump != null) {
 
-            /* remove all jumps to the successor which have the successor
-             * as getNextFlowBlock().  
+		if (jump.prev.outer.jump.destination == jump.destination) {
+		    /* This is a weired "if (cond) empty"-block.  We
+		     * transform it by hand.
 		     */
-            if (jump.prev.outer.getNextFlowBlock(jump.prev) == successor) {
 		    jump.prev.removeJump();
 		    continue next_jump;
 		}
 
-            /* replace all conditional jumps to the successor, which
-             * are followed by a block which has the end of the block
-             * as normal successor, with "if (not condition) block".  
+		/* Swap conditional blocks, that have two jumps, and where
+		 * this jump is the inner jump.  
 		 */
-            if (jump.prev instanceof EmptyBlock &&
-                jump.prev.outer instanceof ConditionalBlock) {
-
 		StructuredBlock prev = jump.prev;
 		ConditionalBlock cb = (ConditionalBlock) prev.outer;
 		jode.Instruction instr = cb.getInstruction();
 		
-
-                if ((cb == appendBlock || 
-                     cb.outer.getNextFlowBlock(cb) == successor 
-                     /*XXX jumpMayBeChanged()??? */) &&
-                    instr instanceof jode.Expression) {
-
+		/* XXX Expression clean up is necessary.  Otherwise
+		 * this may lead to a ClassCastException.
+		 *
+		 * Our code below _depends_ on the fact that this
+		 * transformation is done.
+		 */
 		cb.setInstruction(((jode.Expression)instr).negate());
-                    prev.removeJump();
-                    prev.moveJump(cb);
-                    continue next_jump;
-                }
-
-                /* cb.outer is not null,
-                 * since appendBlock outers cb */
-                
-                if (cb.outer instanceof SequentialBlock && 
-                    cb.outer.getSubBlocks()[0] == cb &&
-                    (cb.outer.getNextFlowBlock() == successor ||
-                     cb.outer.jumpMayBeChanged()) &&
-                    instr instanceof jode.Expression) {
-                    SequentialBlock sequBlock = 
-                        (SequentialBlock) cb.outer;
-                    
-                    IfThenElseBlock newIfBlock = 
-                        new IfThenElseBlock(((jode.Expression)instr).negate());
-
-                    newIfBlock.replace(sequBlock, sequBlock.getSubBlocks()[1]);
-                    newIfBlock.setThenBlock(sequBlock.getSubBlocks()[1]);
-
-                    newIfBlock.moveJump(sequBlock);
-                    if (appendBlock == sequBlock)
-                        appendBlock = newIfBlock;
-
-                    if (newIfBlock.getNextFlowBlock() != successor &&
-                        newIfBlock != appendBlock) {
-                        newIfBlock.moveJump(prev);
-                        continue same_jump;
-                    } else {
-                        prev.removeJump();
-                        continue next_jump;
-                    }
-                }
+                cb.swapJump(jump.prev);
 	    }
 
-            /* if there are jumps in an if-then block, which
-             * have as normal successor the end of the if-then block, and
-             * the if-then block is followed by a single block, then replace
-             * the if-then block with a if-then-else block and remove the
-             * unconditional jump.
+	    /* Now move the jump as far to the outer as possible,
+	     * without leaving appendBlock.
+	     *
+	     * Note: jump.prev != appendblock implies
+	     * jump.prev.outer != null, since appendBlock is an outer
+	     * block of jump.prev 
 	     */
-            StructuredBlock elseBlock = 
-                jump.prev.outer.getNextBlock(jump.prev);
-            if (elseBlock != null
-                && elseBlock.outer != null
-                && elseBlock.outer instanceof SequentialBlock
-                && elseBlock.outer.getSubBlocks()[0] instanceof IfThenElseBlock
-                && (elseBlock.outer.getNextFlowBlock() == successor
-		    || elseBlock.outer.jumpMayBeChanged())) {
-
-                IfThenElseBlock ifBlock = 
-                    (IfThenElseBlock)elseBlock.outer.getSubBlocks()[0];
-
-                if (ifBlock.getSubBlocks().length == 1) {
+	    while (jump.prev != appendBlock
+		   && jump.prev.outer.isSingleExit(jump.prev)) {
+		jump.prev.outer.moveJump(jump);
+	    }
 
-		    /* make sure that only sequential blocks are between
-		     * jump.prev and the ifBlock 
+            /* if the jump is the jump of the appendBlock, skip it.
              */
-		    StructuredBlock block = jump.prev.outer;
-		    while (block instanceof SequentialBlock)
-			block = block.outer;
-
-		    if (block == ifBlock) {
-			elseBlock.outer.removeJump();
-			ifBlock.replace(elseBlock.outer, elseBlock);
-			if (appendBlock == elseBlock.outer)
-			    appendBlock = ifBlock;
-			ifBlock.moveJump(jump.prev);
-			ifBlock.setElseBlock(elseBlock);
-			continue same_jump;
-		    }
-                }
-            }
+            if (jump.prev == appendBlock)
+                continue next_jump;
 
-            /* if the successor is the dummy return instruction, replace all
-             * jumps with a return.
+            /* remove this jump if it jumps to the getNextFlowBlock().  
 	     */
-            if (successor == END_OF_METHOD) {
-                SequentialBlock sequBlock = new SequentialBlock();
-                StructuredBlock prevBlock = jump.prev;
-                prevBlock.removeJump();
-                if (prevBlock instanceof EmptyBlock) {
-                    if (prevBlock.outer instanceof ConditionalBlock) {
-                        IfThenElseBlock ifBlock = 
-                            new IfThenElseBlock
-                            (((ConditionalBlock)prevBlock.outer).
-                             getInstruction());
-                        ifBlock.replace(prevBlock.outer, prevBlock);
-                        ifBlock.moveJump(prevBlock.outer);
-                        ifBlock.setThenBlock(prevBlock);
-                    }
-                    new ReturnBlock().replace(prevBlock, null);
-                } else {
-                    sequBlock.replace(prevBlock, prevBlock);
-                    sequBlock.setFirst(prevBlock);
-                    sequBlock.setSecond(new ReturnBlock());
-                }
+            if (jump.prev.outer.getNextFlowBlock(jump.prev) == successor) {
+                jump.prev.removeJump();
                 continue next_jump;
             }
 
-            /* If this is a conditional jump, the first instruction of
-             * a while and the condition of the while is true,  use
-             * the condition as while condition.
-             */
             if (jump.prev instanceof EmptyBlock &&
-                jump.prev.outer instanceof ConditionalBlock &&
-                jump.prev.outer.jump == null) {
+                jump.prev.outer instanceof ConditionalBlock) {
 
                 StructuredBlock prev = jump.prev;
                 ConditionalBlock cb = (ConditionalBlock) prev.outer;
                 jode.Instruction instr = cb.getInstruction();
 
+                /* cb.jump is null (see above), so cb must have a *
+                 * successor in this block, that means cb.outer is not
+                 * null.
+		 */
+
+		/* If this is the first instruction of a while and the
+		 * condition of the while is true, use the condition
+		 * as while condition.  
+		 */
+
                 /* This is the first instruction in a while block */
                 if (cb.outer instanceof SequentialBlock &&
                     cb.outer.getSubBlocks()[0] == cb &&
@@ -320,10 +243,14 @@ public class FlowBlock {
                         prev.removeJump();
                         loopBlock.setCondition(((Expression)instr).negate());
                         if (cb.outer.jump != null) {
-                            if (cb.outer.getSubBlocks()[1].jump != null)
+			    /* XXX can this happen */
+                            if (cb.outer.getSubBlocks()[1].jump != null) {
+				/* XXX if above can happen,
+				 * can this happen at all??? */
                                 cb.outer.removeJump();
-                            else
-                                cb.outer.getSubBlocks()[1].moveJump(cb.outer);
+                            } else
+                                cb.outer.getSubBlocks()[1].
+				    moveJump(cb.outer.jump);
                         }
                         cb.outer.getSubBlocks()[1].replace
                             (cb.outer, cb.outer.getSubBlocks()[1]);
@@ -354,58 +281,134 @@ public class FlowBlock {
                         continue next_jump;
                     }
                 }
-            }
 
-            /* if there are jumps in a while block or switch block and the
-             * while/switch block is followed by a jump to successor or has
-             * successor as getNextFlowBlock(), replace jump with break to
-             * the innermost such while/switch block.
-             *
-             * If the switch block hasn't been breaked before we could
-             * take some heuristics and add a jump after the switch to
-             * succesor, so that the above succeeds.
+		/* replace all conditional jumps to the successor, which
+		 * are followed by a block which has the end of the block
+		 * as normal successor, with "if (not condition) block".  
 		 */
-            int breaklevel = 0;
-            for (StructuredBlock surrounder = jump.prev.outer;
-                 surrounder != null && surrounder != appendBlock.outer; 
-                 surrounder = surrounder.outer) {
-                if (surrounder instanceof BreakableBlock) {
-                    breaklevel++;
-                    if (surrounder.getNextFlowBlock() == successor ||
-                        surrounder.jumpMayBeChanged()) {
+                if (cb.outer instanceof SequentialBlock && 
+                    cb.outer.getSubBlocks()[0] == cb &&
+                    (cb.outer.getNextFlowBlock() == successor ||
+                     cb.outer.jumpMayBeChanged()) &&
+                    instr instanceof jode.Expression) {
+                    SequentialBlock sequBlock = 
+                        (SequentialBlock) cb.outer;
                     
-                        SequentialBlock sequBlock = new SequentialBlock();
-                        StructuredBlock prevBlock = jump.prev;
-                        if (surrounder.getNextFlowBlock() != successor)
-                            surrounder.moveJump(prevBlock);
-                        else
-                            prevBlock.removeJump();
+                    IfThenElseBlock newIfBlock = 
+                        new IfThenElseBlock(((jode.Expression)instr).negate());
 
-                        if (prevBlock instanceof EmptyBlock) {
-                            if (prevBlock.outer instanceof ConditionalBlock) {
-                                IfThenElseBlock ifBlock = 
-                                    new IfThenElseBlock
-                                    (((ConditionalBlock)prevBlock.outer)
-                                     .getInstruction());
-                                ifBlock.replace(prevBlock.outer, prevBlock);
-                                ifBlock.moveJump(prevBlock.outer);
-                                ifBlock.setThenBlock(prevBlock);
-                            }
-                            new BreakBlock((BreakableBlock) surrounder,
-                                           breaklevel >1
-                                           ).replace(prevBlock, null);
+                    newIfBlock.replace(sequBlock, sequBlock.getSubBlocks()[1]);
+                    newIfBlock.setThenBlock(sequBlock.getSubBlocks()[1]);
+
+                    newIfBlock.moveJump(sequBlock.jump);
+                    if (appendBlock == sequBlock)
+                        appendBlock = newIfBlock;
+
+                    if (newIfBlock.getNextFlowBlock() != successor &&
+                        newIfBlock != appendBlock) {
+                        newIfBlock.moveJump(jump);
+                        continue;
                     } else {
-                            sequBlock.replace(prevBlock, prevBlock);
-                            sequBlock.setFirst(prevBlock);
-                            sequBlock.setSecond
-                                (new BreakBlock((BreakableBlock) surrounder, 
-                                                breaklevel > 1));
+                        prev.removeJump();
+                        continue next_jump;
                     }
-                        continue same_jump;
                 }
             }
+                
+
+            /* if this is a jumps at the end of a then block belonging
+	     * to a if-then block without else part, and the if-then
+	     * block is followed by a single block, then replace the
+	     * if-then block with a if-then-else block and remove the
+	     * unconditional jump.  
+	     */
+            else if (jump.prev.outer instanceof IfThenElseBlock) {
+
+                IfThenElseBlock ifBlock = 
+                    (IfThenElseBlock)jump.prev.outer;
+		if (ifBlock.elseBlock == null
+		    && ifBlock.jump == null
+		    && ifBlock.outer instanceof SequentialBlock
+		    && ifBlock.outer.getSubBlocks()[0] == ifBlock
+		    && (ifBlock.outer.getNextFlowBlock() == successor
+			|| ifBlock.outer.jumpMayBeChanged())) {
+		    
+		    StructuredBlock elseBlock =
+			ifBlock.outer.getSubBlocks()[1];
+
+		    ifBlock.outer.removeJump();
+		    ifBlock.replace(ifBlock.outer, elseBlock);
+
+		    if (appendBlock == elseBlock.outer)
+			appendBlock = ifBlock;
+
+		    ifBlock.moveJump(jump);
+		    ifBlock.setElseBlock(elseBlock);
+		    continue;
+		}
             }
 
+            /* if this is a jump in a breakable block, and that block
+             * has not yet a next block, then create a new jump to that
+             * successor.
+             *
+             * The break to the block will be generated later.
+             */
+
+            for (StructuredBlock surrounder = jump.prev.outer;
+                 surrounder != null && surrounder != appendBlock.outer; 
+                 surrounder = surrounder.outer) {
+                if (surrounder instanceof BreakableBlock) {
+                    if (surrounder.getNextFlowBlock() != successor
+                        && surrounder.jumpMayBeChanged()) {
+
+                        surrounder.setJump(new Jump(successor));
+                        successors.addElement(surrounder.jump);
+                    }
+                }
+            }
+
+// 	    /* XXX - There is a problem with this.
+// 	     * The here created break could be obsoleted later.
+// 	     * We should instead only add the jump to surrounder
+// 	     * if necessary and add the break after all jumps
+// 	     * has been considered.
+// 	     */
+
+//             /* if there are jumps in a while block or switch block and the
+//              * while/switch block is followed by a jump to successor or has
+//              * successor as getNextFlowBlock(), replace jump with break to
+//              * the innermost such while/switch block.
+//              *
+//              * If the switch block hasn't been breaked before we could
+//              * take some heuristics and add a jump after the switch to
+//              * succesor, so that the above succeeds.
+//              */
+//             int breaklevel = 0;
+//             for (StructuredBlock surrounder = jump.prev.outer;
+//                  surrounder != null && surrounder != appendBlock.outer; 
+//                  surrounder = surrounder.outer) {
+//                 if (surrounder instanceof BreakableBlock) {
+//                     breaklevel++;
+//                     if (surrounder.getNextFlowBlock() == successor ||
+//                         surrounder.jumpMayBeChanged()) {
+
+//                         SequentialBlock sequBlock = new SequentialBlock();
+//                         StructuredBlock prevBlock = jump.prev;
+//                         if (surrounder.getNextFlowBlock() != successor)
+//                             surrounder.moveJump(prevBlock.jump);
+//                         else {
+//                             prevBlock.removeJump();
+// 			    jump = null;
+// 			}
+
+// 			prevBlock.appendBlock
+// 			    (new BreakBlock((BreakableBlock) surrounder,
+// 					    breaklevel >1));
+//                         continue;
+//                     }
+//                 }
+//             }
             continue next_jump;
         }
         }
@@ -419,23 +422,23 @@ public class FlowBlock {
      * block.  
      * @return The variables that must be defined in this block.
      */
-    VariableSet updateInOut (FlowBlock successor, boolean t1Transformation) {
+    void updateInOut (FlowBlock successor, boolean t1Transformation) {
         /* First get the out vectors of all jumps to successor and
          * calculate the intersection.
          */
-        VariableSet allOuts = new VariableSet();
-        VariableSet intersectOut = null;
+        VariableSet gens = new VariableSet();
+        VariableSet kills =  null;
         Enumeration enum = successors.elements();
         while (enum.hasMoreElements()) {
             Jump jump = (Jump) enum.nextElement();
             if (jump == null || jump.destination != successor)
                 continue;
             
-            allOuts.union(jump.out);
-            if (intersectOut == null) 
-                intersectOut = jump.out;
+            gens.unionExact(jump.gen);
+            if (kills == null) 
+                kills = jump.kill;
             else
-                intersectOut = intersectOut.intersect(jump.out);
+                kills = kills.intersect(jump.kill);
         }
 
 //         System.err.println("UpdateInOut: allOuts     : "+allOuts);
@@ -444,26 +447,25 @@ public class FlowBlock {
         /* Merge the locals used in successing block with those written
          * by this blocks
          */
-        VariableSet defineHere = successor.in.merge(allOuts);
-        defineHere.subtractExact(in);
+        successor.in.merge(gens);
         
-//         System.err.println("             defineHere  : "+defineHere);
-        if (t1Transformation) {
         /* Now update in and out set of successing block */
-            successor.in.subtract(intersectOut);
-            /* The out set must be updated for every jump in the block */
+
+        if (t1Transformation)
+            successor.in.subtract(kills);
+        /* The gen/kill sets must be updated for every jump in the block */
         enum = successor.successors.elements();
         while (enum.hasMoreElements()) {
             Jump jump = (Jump) enum.nextElement();
-                if (jump != null)
-                    jump.out.add(intersectOut);
+            if (jump != null) {
+                jump.gen.mergeGenKill(gens, jump.kill);
+                if (t1Transformation)
+                    jump.kill.add(kills);
             }
         }
 //         System.err.println("             successor.in: "+successor.in);
-        in.union(successor.in);
+        in.unionExact(successor.in);
 //         System.err.println("             in          : "+in);
-        /* XXX - do something with defineHere */
-        return defineHere; /*XXX - correct???*/
     }
     
 
@@ -566,6 +568,8 @@ public class FlowBlock {
     }
 
     public void checkConsistent() {
+        if (!jode.Decompiler.doChecks)
+            return;
         if (block.outer != null || block.flowBlock != this) {
             throw new RuntimeException("Inconsistency");
         }
@@ -611,11 +615,7 @@ public class FlowBlock {
             return false;
 
         try{
-//             System.err.println("doing T1 analysis on: "+getLabel());
-//             System.err.println("***in: "+in);
             checkConsistent();
-//             System.err.println("and "+succ.getLabel());
-//             System.err.println("+++in: "+succ.in);
             succ.checkConsistent();
         } catch (RuntimeException ex) {
             ex.printStackTrace();
@@ -658,7 +658,7 @@ public class FlowBlock {
         }
 
         /* Update the in/out-Vectors now */
-        VariableSet defineHere = updateInOut(succ, true);
+        updateInOut(succ, true);
 
         /* The switch "fall through" case: if the appendBlock is a
          * switch, and the successor is the address of a case, and all
@@ -669,7 +669,7 @@ public class FlowBlock {
 	if (appendBlock instanceof SwitchBlock) {
 	    nextcase = ((SwitchBlock) appendBlock).findCase(succ);
 	    precedingcase = 
-		((SwitchBlock) appendBlock).prevCase(precedingcase);
+		((SwitchBlock) appendBlock).prevCase(nextcase);
 	    
 	    enum = successors.elements();
 	    while (nextcase != null && enum.hasMoreElements()) {
@@ -680,7 +680,6 @@ public class FlowBlock {
 		    || (precedingcase != null 
 			&& precedingcase.contains(jump.prev)))
 		    continue;
-		
                 nextcase = null;
 	    }
 	}
@@ -696,8 +695,6 @@ public class FlowBlock {
 
             /* Do the following modifications on the struct block. */
             appendBlock = precedingcase;
-            succ.block.setFlowBlock(this);
-//             switchBlock.define(defineHere);
 
         } else {
 
@@ -723,8 +720,6 @@ public class FlowBlock {
             sequBlock.replace(appendBlock, appendBlock);
             sequBlock.setFirst(appendBlock);
             sequBlock.setSecond(succ.block);
-            succ.block.setFlowBlock(this);
-//             sequBlock.define(defineHere);
         }
 
         /* Merge the sucessors from the successing flow block
@@ -744,7 +739,6 @@ public class FlowBlock {
         }
 
             try {
-//             System.err.println("before optimizeJump: "+getLabel());
                 checkConsistent();
             } catch (RuntimeException ex) {
                 ex.printStackTrace();
@@ -760,10 +754,15 @@ public class FlowBlock {
         /* Try to eliminate as many jumps as possible.
          */
 
+	/* appendBlock may be zero, if this is the switchcase with
+	 * precedingcase = null.  But in this case, there can't be
+	 * any jumps.
+	 */
+	if (appendBlock != null) {
+	    
             appendBlock = optimizeJumps(succ, appendBlock);
             
             try {
-//             System.err.println("after optimizeJump: "+getLabel());
                 checkConsistent();
             } catch (RuntimeException ex) {
                 ex.printStackTrace();
@@ -776,56 +775,71 @@ public class FlowBlock {
                 }
             }
 
-	/* appendBlock may be zero, if this is the switchcase with
-	 * precedingcase = null.  But in this case, there can't be
-	 * any jumps.
-	 */
-	if (appendBlock != null) {
-	    /* Now remove the jump of the appendBlock if it points to
-	     * successor.  
-	     */
-	    if (appendBlock.jump != null
-		&& appendBlock.jump.destination == succ)
-		appendBlock.removeJump();
-	    
-	    /* If there are further jumps, put a do/while(0) block around
-	     * appendBlock and replace every remaining jump with a break
-	     * to the do/while block.
-	     */
 	    LoopBlock doWhileFalse = null;
 	    enum = successors.elements();
+        next_jump:
 	    while (enum.hasMoreElements()) {
 		Jump jump = (Jump) enum.nextElement();
 	    
-		if (jump == null || jump.destination != succ)
+		if (jump == null || jump.destination != succ ||
+                    jump.prev == appendBlock)
 		    continue;
 		
-		if (doWhileFalse == null)
-		    doWhileFalse = new LoopBlock(LoopBlock.DOWHILE, 
-						 LoopBlock.FALSE);
-		
-		int breaklevel = 1;
+                int breaklevel = 0;
+                BreakableBlock breakToBlock = null;
                 for (StructuredBlock surrounder = jump.prev.outer;
-		     surrounder != appendBlock.outer; 
+                     surrounder != null && surrounder != appendBlock.outer; 
                      surrounder = surrounder.outer) {
                     if (surrounder instanceof BreakableBlock) {
                         breaklevel++;
+                        if (surrounder.getNextFlowBlock() == succ) {
+                            breakToBlock = (BreakableBlock) surrounder;
+                            break;
+                        }
+                        /* We don't want labeled breaks, if we can
+                         * simply return.  */
+                        if (succ == END_OF_METHOD)
+                            break;
                     }
                 }
 
-		SequentialBlock sequBlock = new SequentialBlock();
                 StructuredBlock prevBlock = jump.prev;
                 prevBlock.removeJump();
 
-		sequBlock.replace(prevBlock, prevBlock);
-		sequBlock.setFirst(prevBlock);
-		sequBlock.setSecond(new BreakBlock(doWhileFalse, breaklevel > 1));
+                if (breakToBlock == null) {
+                    /* if the successor is the dummy return instruction
+                     * and no simple breakToBlock could be found above,
+                     * replace the jump with a return.  
+                     */
+                    if (succ == END_OF_METHOD && breakToBlock == null)
+                        prevBlock.appendBlock(new ReturnBlock());
+                    else {
+                        /* Nothing else helped, so put a do/while(0)
+                         * block around appendBlock and break to that
+                         * block.
+                         */
+                        if (doWhileFalse == null)
+                            doWhileFalse = new LoopBlock(LoopBlock.DOWHILE, 
+                                                         LoopBlock.FALSE);
+                        prevBlock.appendBlock
+                            (new BreakBlock(doWhileFalse, breaklevel > 0));
+                    }
+                } else
+                    prevBlock.appendBlock
+                        (new BreakBlock(breakToBlock, breaklevel > 1));
 	    }
 	    
 	    if (doWhileFalse != null) {
 		doWhileFalse.replace(appendBlock, appendBlock);
 		doWhileFalse.setBody(appendBlock);
 	    }
+
+	    /* Now remove the jump of the appendBlock if it points to
+	     * successor.  
+	     */
+	    if (appendBlock.jump != null
+		&& appendBlock.jump.destination == succ)
+		appendBlock.removeJump();
 	}
 	    
 	/* Believe it or not: Now the rule, that the first part of a
@@ -899,7 +913,7 @@ public class FlowBlock {
         }
 
         /* Update the in/out-Vectors now */
-        VariableSet defineHere = updateInOut(this, false);
+        updateInOut(this, false);
 
 	
 	while (lastModified != block) {
@@ -945,7 +959,6 @@ public class FlowBlock {
 
             whileBlock.replace(bodyBlock, bodyBlock);
             whileBlock.setBody(bodyBlock);
-//             whileBlock.define(defineHere);
 
             /* Try to eliminate as many jumps as possible.
              */
@@ -1069,13 +1082,13 @@ public class FlowBlock {
         }
 
         if (!in.isEmpty()) {
-            writer.print("in: "+in);
+            writer.println("in: "+in);
         }
 
         block.dumpSource(writer);
-        FlowBlock succ = getSuccessor();
-        if (succ != null)
-            succ.dumpSource(writer);
+//         FlowBlock succ = getSuccessor();
+//         if (succ != null)
+//             succ.dumpSource(writer);
     }
 
     /**

jode/jode/flow/IfThenElseBlock.java

@@ -96,7 +96,7 @@ public class IfThenElseBlock extends StructuredBlock {
     public void dumpInstruction(TabbedPrintWriter writer)
         throws java.io.IOException
     {
-        boolean needBrace = ! (thenBlock instanceof InstructionBlock);
+        boolean needBrace = thenBlock.needsBraces();
         writer.println("if ("+cond.toString()+")"+(needBrace?" {":""));
         writer.tab();
         thenBlock.dumpSource(writer);
@@ -109,7 +109,7 @@ public class IfThenElseBlock extends StructuredBlock {
                 writer.print("else ");
                 elseBlock.dumpSource(writer);
             } else {
-                needBrace = ! (elseBlock instanceof InstructionBlock);
+                needBrace = elseBlock.needsBraces();
                 writer.println("else" + (needBrace ? " {" : ""));
                 writer.tab();
                 elseBlock.dumpSource(writer);
@@ -139,12 +139,8 @@ public class IfThenElseBlock extends StructuredBlock {
      * @return true, if the jump may be safely changed.
      */
     public boolean jumpMayBeChanged() {
-        if (thenBlock.jump == null && !thenBlock.jumpMayBeChanged())
-            return false;
-
-        if (elseBlock != null && elseBlock.jump == null &&
-            !elseBlock.jumpMayBeChanged())
-            return false;
-        return true;
+        return (thenBlock.jump != null || thenBlock.jumpMayBeChanged())
+            && elseBlock != null
+            && (elseBlock.jump != null || elseBlock.jumpMayBeChanged());
     }
 }

jode/jode/flow/InstructionBlock.java

@@ -31,6 +31,14 @@ public class InstructionBlock extends InstructionContainer {
         super(instr, jump);
     }
 
+    /**
+     * Tells if this block needs braces when used in a if or while block.
+     * @return true if this block should be sorrounded by braces.
+     */
+    public boolean needsBraces() {
+        return declare != null && !declare.isEmpty();
+    }
+
     /**
      * True if this is a declaration.
      */
@@ -42,7 +50,7 @@ public class InstructionBlock extends InstructionContainer {
         if (instr instanceof Expression
             && ((Expression)instr).getOperator() instanceof LocalStoreOperator
             && ((LocalStoreOperator) ((Expression)instr).getOperator())
-            .getLocalInfo() == local) {
+            .getLocalInfo() == local.getLocalInfo()) {
             isDeclaration = true;
         } else
             super.dumpDeclaration(writer, local);

jode/jode/flow/InstructionContainer.java

@@ -36,7 +36,8 @@ public abstract class InstructionContainer extends StructuredBlock {
         if (instr instanceof LocalVarOperator) {
             LocalVarOperator varOp = (LocalVarOperator) instr;
 	    used.addElement(varOp.getLocalInfo());
-            jump.out.addElement(varOp.getLocalInfo());
+            jump.gen.addElement(varOp.getLocalInfo());
+            jump.kill.addElement(varOp.getLocalInfo());
         }
         setJump(jump);
     }

jode/jode/flow/Jump.java

@@ -36,12 +36,21 @@ public class Jump {
     int destAddr;
 
     /**
-     * The out locals.  This are the locals, which must be overwritten
+     * The kill locals.  This are the slots, which must be overwritten
      * in this block on every path to this jump.  That means, that all
      * paths form the start of the current flow block to this jump
-     * contain (unconditional) assignments to this local.
+     * contain (unconditional) assignments to this slot.
      */
-    VariableSet out = new VariableSet();
+    VariableSet kill = new VariableSet();
+
+    /**
+     * The gen locals.  This are the locals, which can be overwritten
+     * in this block on a path to this jump.  That means, that there
+     * exists a path form the start of the current flow block to this
+     * jump that contains an (unconditional) assignments to this
+     * local, and that is not overwritten afterwards.  
+     */
+    VariableSet gen = new VariableSet();
 
     public Jump (int destAddr) {
         this.destAddr = destAddr;
@@ -75,7 +84,8 @@ public class Jump {
         throws java.io.IOException
     {
         if (jode.Decompiler.isDebugging) {
-            writer.println("out: "+ out.toString());
+            writer.println("gen : "+ gen.toString());
+            writer.println("kill: "+ kill.toString());
         }
         writer.println("Attachments: "+describeAttachments());
         if (destination == null)

jode/jode/flow/LoopBlock.java

@@ -135,7 +135,7 @@ public class LoopBlock extends StructuredBlock implements BreakableBlock {
             writer.println(label+":");
             writer.tab();
         }
-        boolean needBrace = ! (bodyBlock instanceof InstructionBlock);
+        boolean needBrace = bodyBlock.needsBraces();
         switch (type) {
         case WHILE:
             writer.print("while ("+cond.toString()+")");

jode/jode/flow/RemoveEmpty.java

@@ -33,8 +33,9 @@ public class RemoveEmpty implements Transformation {
         Instruction instr;
         try {
             block = flow.lastModified;
-            if (!(((InstructionContainer)block).getInstruction() 
-                  instanceof NopOperator))
+            Instruction prevInstr = 
+                ((InstructionContainer)block).getInstruction();
+            if (!(prevInstr instanceof NopOperator))
                 return false;
             
             sequBlock = (SequentialBlock)block.outer;
@@ -46,6 +47,8 @@ public class RemoveEmpty implements Transformation {
             if (prev.jump != null)
                 return false;
             instr = (Instruction) prev.getInstruction();
+            instr.setType(jode.MyType.intersection
+                          (instr.getType(), prevInstr.getType()));
         } catch (NullPointerException ex) {
             return false;
         } catch (ClassCastException ex) {
@@ -66,7 +69,8 @@ public class RemoveEmpty implements Transformation {
             StructuredBlock block = lastBlock.outer.getSubBlocks()[0];
             block.replace(block.outer, block);
             if (block.jump == null)
-                block.moveJump(lastBlock);
+		/*XXX can this happen */
+                block.moveJump(lastBlock.jump);
             else
                 lastBlock.removeJump();
             flow.lastModified = block;

jode/jode/flow/ReturnBlock.java

@@ -34,6 +34,14 @@ public class ReturnBlock extends InstructionContainer {
         super(instr);
     }
 
+    /**
+     * Tells if this block needs braces when used in a if or while block.
+     * @return true if this block should be sorrounded by braces.
+     */
+    public boolean needsBraces() {
+        return false;
+    }
+
     /**
      * Get the underlying instruction.
      * @return the underlying instruction.

jode/jode/flow/SequentialBlock.java

@@ -63,6 +63,16 @@ public class SequentialBlock extends StructuredBlock {
         return getNextFlowBlock();
     }
 
+    /**
+     * Tells if the sub block is the single exit point of the current block.
+     * @param subBlock the sub block.
+     * @return true, if the sub block is the single exit point of the
+     * current block.  
+     */
+    public boolean isSingleExit(StructuredBlock subBlock) {
+	return (subBlock == subBlocks[1]);
+    }
+    
     /**
      * Make the declarations, i.e. initialize the declare variable
      * to correct values.  This will declare every variable that
@@ -74,6 +84,7 @@ public class SequentialBlock extends StructuredBlock {
 	 * any local Variable, but let the first sub block do this.
 	 */
 	declare = new VariableSet();
+        subBlocks[0].used.addExact(used);
 	subBlocks[0].makeDeclaration(done);
 	done.addExact(used);
 	subBlocks[1].makeDeclaration(done);

jode/jode/flow/SimplifyExpression.java

@@ -21,10 +21,20 @@ package jode.flow;
 
 public class SimplifyExpression implements Transformation {
     public boolean transform(FlowBlock flow) {
+//         try {
+//             jode.TabbedPrintWriter writer = 
+//                 new jode.TabbedPrintWriter(System.err, "    ");
+//             System.out.println("Transforming: ");
+//             flow.lastModified.dumpSource(writer);
         if (flow.lastModified instanceof InstructionContainer) {
             InstructionContainer ic = (InstructionContainer) flow.lastModified;
             ic.setInstruction(ic.getInstruction().simplify());
         }
+//             System.out.println("Result: ");
+//             flow.lastModified.dumpSource(writer);
+//         } catch (java.io.IOException ex) {
+//         }
+
         return false;
     }
 }

jode/jode/flow/StructuredBlock.java

@@ -150,6 +150,16 @@ public abstract class StructuredBlock {
         return getNextFlowBlock();
     }
 
+    /**
+     * Tells if the sub block is the single exit point of the current block.
+     * @param subBlock the sub block.
+     * @return true, if the sub block is the single exit point of the
+     * current block.  
+     */
+    public boolean isSingleExit(StructuredBlock subBlock) {
+	return false;
+    }
+
     /**
      * Replaces the given sub block with a new block.
      * @param oldBlock the old sub block.
@@ -180,11 +190,8 @@ public abstract class StructuredBlock {
     }
 
     /** 
-     * Removes the given jump if it is our jump.  This does also
-     * update the successors vector of the flow block.  
-     *
-     * @param jump  The jump that should be removed.  
-     */
+     * Removes the jump.  This does also update the successors vector
+     * of the flow block.  */
     public void removeJump() {
         if (jump != null) {
             jump.prev = null;
@@ -211,8 +218,8 @@ public abstract class StructuredBlock {
             while (enum.hasMoreElements()) {
                 LocalInfo var = 
                     ((LocalInfo) enum.nextElement()).getLocalInfo();
+                if (!used.contains(var))
                     used.addElement(var);
-                var.setDefining(this);
             }
             from.used.removeAllElements();
             StructuredBlock[] subs = from.getSubBlocks();
@@ -236,8 +243,7 @@ public abstract class StructuredBlock {
     public void replace(StructuredBlock sb, StructuredBlock sub) {
         moveDefinitions(sb, sub);
         outer = sb.outer;
-        flowBlock = sb.flowBlock;
-
+        setFlowBlock(sb.flowBlock);
         if (outer != null) {
             outer.replaceSubBlock(sb, this);
         } else {
@@ -246,18 +252,45 @@ public abstract class StructuredBlock {
     }
 
     /**
-     * This function moves the jumps from sb to this block.  
-     * The jump field of sb is removed afterwards.  
-     * @param sb  The structured block whose jump is copied.
+     * This function swaps the jump with another block.
+     * @param block The block whose jump is swapped.
+     */
+    public void swapJump(StructuredBlock block) {
+        Jump tmp = block.jump;
+        block.jump = jump;
+        jump = tmp;
+        
+        jump.prev = this;
+        block.jump.prev = block;
+    }
+
+    /**
+     * This function moves the jump to this block.  
+     * The jump field of the previous owner is cleared afterwards.  
+     * If the given jump is null, nothing bad happens.
+     * @param jump The jump that should be moved, may be null.
      */
-    public void moveJump(StructuredBlock sb) {
-        jump = sb.jump;
+    public void moveJump(Jump jump) {
+	removeJump();
+        this.jump = jump;
         if (jump != null) {
+            jump.prev.jump = null;
             jump.prev = this;
-            sb.jump = null;
         }
     }
 
+    /**
+     * Appends a block to this block.
+     * @return the new combined block.
+     */
+    public StructuredBlock appendBlock(StructuredBlock block) {
+	SequentialBlock sequBlock = new SequentialBlock();
+	sequBlock.replace(this, this);
+	sequBlock.setFirst(this);
+	sequBlock.setSecond(block);
+	return sequBlock;
+    }
+
     /**
      * Determines if there is a sub block, that flows through to the end
      * of this block.  If this returns true, you know that jump is null.
@@ -277,18 +310,14 @@ public abstract class StructuredBlock {
 
     public VariableSet propagateUsage() {
         StructuredBlock[] subs = getSubBlocks();
-        VariableSet[] childUse = new VariableSet[subs.length];
         VariableSet allUse = (VariableSet) used.clone();
         for (int i=0; i<subs.length; i++) {
-            childUse[i] = subs[i].propagateUsage();
-            allUse.addExact(childUse[i]);
-        }
-        if (subs.length == 2) {
-            /* All variables used in both sub blocks, are used in
-             * this block, too.  
+            VariableSet childUse = subs[i].propagateUsage();
+            /* All variables used in more than one sub blocks, are
+             * used in this block, too.  
              */
-            VariableSet newUse = childUse[0].intersectExact(childUse[1]);
-	    used.addExact(newUse);
+            used.addExact(allUse.intersectExact(childUse));
+            allUse.addExact(childUse);
         }
         return allUse;
     }
@@ -341,11 +370,20 @@ public abstract class StructuredBlock {
             this.flowBlock = flowBlock;
             StructuredBlock[] subs = getSubBlocks();
             for (int i=0; i<subs.length; i++) {
+                if (subs[i] != null)
                     subs[i].setFlowBlock(flowBlock);
             }
         }
     }
 
+    /**
+     * Tells if this block needs braces when used in a if or while block.
+     * @return true if this block should be sorrounded by braces.
+     */
+    public boolean needsBraces() {
+        return true;
+    }
+
     /**
      * Fill all in variables into the given VariableSet.
      * @param in The VariableSet, the in variables should be stored to.
@@ -377,14 +415,18 @@ public abstract class StructuredBlock {
     public void dumpSource(jode.TabbedPrintWriter writer)
         throws java.io.IOException
     {
-        if (jode.Decompiler.isDebugging)
+	if (declare != null) {
+	    if (jode.Decompiler.isDebugging) {
 		writer.println("declaring: "+declare);
+		writer.println("using: "+used);
+            }
 
 	    java.util.Enumeration enum = declare.elements();
 	    while (enum.hasMoreElements()) {
 		LocalInfo local = (LocalInfo) enum.nextElement();
 		dumpDeclaration(writer, local);
 	    }
+	}
         dumpInstruction(writer);
 
         if (jump != null)

jode/jode/flow/VariableSet.java

@@ -116,7 +116,7 @@ public class VariableSet extends java.util.Vector {
     /**
      * Union the other variable set to the current.
      */
-    public void union(VariableSet vs) {
+    public void unionExact(VariableSet vs) {
         int oldSize = elementCount;
     iloop:
         for (int i=0; i< vs.elementCount; i++) {
@@ -172,6 +172,27 @@ public class VariableSet extends java.util.Vector {
         }
     }
 
+    /**
+     * Add the variables in gen to the current set, unless there are
+     * variables in kill using the same slot.
+     * @param gen The gen set.
+     * @param kill The kill set.
+     */
+    public void mergeGenKill(VariableSet gen, VariableSet kill) {
+    iloop:
+        for (int i=0; i< gen.elementCount; i++) {
+            LocalInfo li2 = ((LocalInfo) gen.elementData[i]).getLocalInfo();
+            /* check if this slot was already overwritten (kill set) */
+            for (int j=0; j< kill.elementCount; j++) {
+                LocalInfo li1 = (LocalInfo) kill.elementData[j];
+                if (li2.getSlot() == li1.getSlot())
+                    /* Yes it was, take next variable */
+                    continue iloop;
+            }
+            addElement(li2);
+        }
+    }
+
     /**
      * Subtract the other variable set from this one.  This removes
      * every variable from this set, that uses a slot in the other