import java.util.Iterator;

aspect ConstantFolding {	

	class CFMap extends HashMap {
		
		public final static long UNDEF = -99999999;
		public final static long NAC   = -99999998;
		
		public CFMap(BitSet locals) {			
			for(Iterator iter = locals.iterator(); iter.hasNext();){
				Variable v = (Variable)iter.next();
				if(v.type() instanceof IntType ||
				   v.type() instanceof LongType ||
				   v.type() instanceof ShortType)//IntegralType)//PrimitiveType)
					this.put(v, UNDEF);			
			}	
		}
		
		public CFMap() {
			super();
		}
		
		public CFMap intersect(CFMap map) {
			Iterator iter = keySet().iterator();

			CFMap out = copy();
			while(iter.hasNext()) {
				Variable key = (Variable)iter.next();
			    Long val1 = (Long)this.get(key);
				Long val2 = (Long)map.get(key);
				if(val1 == UNDEF) 
					out.put(key, val2);
				else if(val1 == NAC)
					continue;	
				else { //val1 = const
					if(val2 == UNDEF || val1 == val2)
						continue;
					else
						out.put(key, NAC);					
				}
			}
			
			return out;				
		}
		
		public CFMap copy() {
			CFMap map = new CFMap();
			for(Iterator iter = keySet().iterator();iter.hasNext();){
				Variable key = (Variable)iter.next();
				map.put(key, get(key));
			}
			return map;
		}
		
		public static long add(long left, long right) {
			if(left == CFMap.NAC || right == CFMap.NAC)
				return CFMap.NAC;
			else if(left != NAC && left != UNDEF && //const
					right!= NAC && right != UNDEF) 
				return left + right;
			else
				return CFMap.UNDEF;
		}
		
		public static long sub(long left, long right) {
			if(left == CFMap.NAC || right == CFMap.NAC)
				return CFMap.NAC;
			else if(left != NAC && left != UNDEF && //const
					right!= NAC && right != UNDEF) 
				return left - right;
			else
				return CFMap.UNDEF;
		}
		
		public static long mul(long left, long right) {
			if(left == CFMap.NAC || right == CFMap.NAC)
				return CFMap.NAC;
			else if(left != NAC && left != UNDEF && //const
					right!= NAC && right != UNDEF) 
				return left * right;
			else
				return CFMap.UNDEF;
		}
		
		public static long div(long left, long right) {
			if(left == CFMap.NAC || right == CFMap.NAC)
				return CFMap.NAC;
			else if(left != NAC && left != UNDEF && //const
					right!= NAC && right != UNDEF) 
				return left / right;
			else
				return CFMap.UNDEF;
		}
		
		public static long mod(long left, long right) {
			if(left == CFMap.NAC || right == CFMap.NAC)
				return CFMap.NAC;
			else if(left != NAC && left != UNDEF && //const
					right!= NAC && right != UNDEF) 
				return left % right;
			else
				return CFMap.UNDEF;
		}
			

	}
/*	
	interface CFValue {}
	class UNDEF implements CFValue {}
	class NAC implements CFValue {}
	
	class CFConst implements CFValue {}
	class CFIntConst extends CFConst {
		int val;
	}	
	class CFBoolConst extends CFConst {
		boolean val;
	}	
*/	
	
	// undefMap()
	syn CFMap Expr.undefMap() = new CFMap(locals());
	syn CFMap Stmt.undefMap() = new CFMap(locals());

	
	/*
	syn CFMap CFGNode.undefMap();
	eq Expr.undefMap() = new CFMap(locals());
	eq Stmt.undefMap() = new CFMap(locals());*/
	
	// in_cf()
	syn CFMap Expr.in_cf() circular [undefMap()];
	syn CFMap Stmt.in_cf() circular [undefMap()];
	//syn CFMap CFGNode.in_cf() circular [undefMap()];
	eq Stmt.in_cf() {

		Iterator iter = pred().iterator();
		if(!iter.hasNext())
			return undefMap();
		
		Object o = iter.next();
		CFMap map;
		if(o instanceof Expr)
			map = ((Expr)o).out_cf().copy();
		else if(o instanceof Stmt)
			map = ((Stmt)o).out_cf().copy();
		else 
			throw new Error("Stmt.in_cf()");
		while(iter.hasNext()) {
			Object o2 = iter.next();
			CFMap map2;
			if(o2 instanceof Expr)
				map2 = ((Expr)o2).out_cf();
			else if(o2 instanceof Stmt)
				map2 = ((Stmt)o2).out_cf();	
			else 
				throw new Error("Stmt.in_cf()");
			map = map.intersect(map2);
		}
		return map;

	}	
	
	eq Expr.in_cf() {
/*
		Iterator iter = pred().iterator();
		if(!iter.hasNext())
			return undefMap();
		CFMap map = ((CFGNode)iter.next()).out_cf();
		while(iter.hasNext())
			map = map.intersect(((CFGNode)iter.next()).out_cf());
		return map;
*/
		Iterator iter = pred().iterator();
		if(!iter.hasNext())
			return undefMap();
		
		Object o = iter.next();
		CFMap map;
		if(o instanceof Expr)
			map = ((Expr)o).out_cf().copy();
		else if(o instanceof Stmt)
			map = ((Stmt)o).out_cf().copy();
		else 
			throw new Error("Expr.in_cf()");
		while(iter.hasNext()) {
			Object o2 = iter.next();
			CFMap map2;
			if(o2 instanceof Expr)
				map2 = ((Expr)o2).out_cf();
			else if(o2 instanceof Stmt)
				map2 = ((Stmt)o2).out_cf();	
			else
				throw new Error("Expr.in_cf()");
			map = map.intersect(map2);
		}
		return map;
		
	}	
	
	
	// out_cf()
	syn CFMap Expr.out_cf() circular [undefMap()];
	syn CFMap Stmt.out_cf() circular [undefMap()];
	//syn CFMap CFGNode.out_cf() circular [undefMap()];
	eq Expr.out_cf() = in_cf();
	eq Stmt.out_cf() = in_cf();
	
	//eq AssignSimpleExpr.out_cf() 
	eq AssignExpr.out_cf() {
		if(!(getDest() instanceof VarAccess))
			return super.out_cf();	
		Variable dest = ((VarAccess)getDest()).decl();
		Expr source = getSource();
		
		if(in_cf().containsKey(dest)) {	
			
			//System.out.println("** Assign:"+this);
			
			CFMap map = in_cf().copy();
			if(this instanceof AssignSimpleExpr)
				map.put(dest, source.calcuConst());
			else if(this instanceof AssignPlusExpr) {
				long val = CFMap.add((Long)map.get(dest), source.calcuConst());
				map.put(dest, val);
			}
			else if(this instanceof AssignMinusExpr) {
				long val = CFMap.sub((Long)map.get(dest), source.calcuConst());
				map.put(dest, val);
			}
			else if(this instanceof AssignMulExpr) {
				long val = CFMap.mul((Long)map.get(dest), source.calcuConst());
				map.put(dest, val);
			}
			else if(this instanceof AssignDivExpr) {
				long val = CFMap.div((Long)map.get(dest), source.calcuConst());
				map.put(dest, val);
			}
			else if(this instanceof AssignModExpr) {
				long val = CFMap.mod((Long)map.get(dest), source.calcuConst());
				map.put(dest, val);
			}
					
			return map;
		}
		else
			return super.out_cf();
			//return in_cf();
	}
	
	eq VariableDeclaration.out_cf() {
		if(hasInit() && in_cf().containsKey(this)) {	
			CFMap map = in_cf().copy();			
			map.put(this, getInit().calcuConst());
			return map;
		}
		else
			return in_cf();
	}
	
	eq PreIncExpr.out_cf() {
		if(!(getOperand() instanceof VarAccess)) //++a[1]
			return in_cf();
		Variable op = ((VarAccess)getOperand()).decl();
		if(!in_cf().containsKey(op))
			return in_cf();
		long val = (Long)in_cf().get(op);
		if(val == CFMap.NAC || val == CFMap.UNDEF)
			return in_cf();
		CFMap map = in_cf().copy();
		map.put(op, val+1);
		return map;
	}
	
	eq PostIncExpr.out_cf() {
		if(!(getOperand() instanceof VarAccess))
			return in_cf();
		Variable op = ((VarAccess)getOperand()).decl();
		if(!in_cf().containsKey(op))
			return in_cf();
		long val = (Long)in_cf().get(op);
		if(val == CFMap.NAC || val == CFMap.UNDEF)
			return in_cf();
		CFMap map = in_cf().copy();
		map.put(op, val+1);
		return map;
	}
	
	eq PreDecExpr.out_cf() {
		if(!(getOperand() instanceof VarAccess))
			return in_cf();
		Variable op = ((VarAccess)getOperand()).decl();
		if(!in_cf().containsKey(op))
			return in_cf();
		long val = (Long)in_cf().get(op);
		if(val == CFMap.NAC || val == CFMap.UNDEF)
			return in_cf();
		CFMap map = in_cf().copy();
		map.put(op, val-1);
		return map;
	}
	
	eq PostDecExpr.out_cf() {
		if(!(getOperand() instanceof VarAccess))
			return in_cf();
		Variable op = ((VarAccess)getOperand()).decl();
		if(!in_cf().containsKey(op))
			return in_cf();
		long val = (Long)in_cf().get(op);
		if(val == CFMap.NAC || val == CFMap.UNDEF)
			return in_cf();
		CFMap map = in_cf().copy();
		map.put(op, val-1);
		return map;
	}
	
	/*
	eq Unary.out_cf() {

		if(!(getOperand() instanceof VarAccess))
			return in_cf();
		Variable op = ((VarAccess)getOperand()).decl();
		if(!in_cf().containsKey(op))
			return in_cf();
		long val = (Long)in_cf().get(op);

		
		if(this instanceof PreIncExpr || this instanceof PostIncExpr) {	
			//System.out.println("** PreExpr:"+this);
			//System.err.println("Source_File: "+sourceFile());
  			//System.err.println("Line_Number: "+lineNumber()+"\n");
			long val = getOperand().calcuConst();
			if(val == CFMap.NAC || val == CFMap.UNDEF)
				return in_cf();
			CFMap map = in_cf().copy();
			map.put(op, val+1);
			return map;
		}
		else if(this instanceof PreDecExpr || this instanceof PostDecExpr) {
			//System.out.println("** PostExpr:"+this);
			CFMap map = in_cf().copy();
			map.put(op, val-1);
			return map;
		}
		else
			return in_cf();
			
	}*/
	
	

	
	syn long Expr.calcuConst() = CFMap.NAC;
	eq VarAccess.calcuConst() {
		if(in_cf().containsKey(decl()))
			return (Long)in_cf().get(decl());
		else
			return CFMap.NAC;
	}
	
	eq IntegerLiteral.calcuConst() = Long.parseLong(getLITERAL());	
	eq LongLiteral.calcuConst() = Long.parseLong(getLITERAL());	
		
	
	eq ArithmeticExpr.calcuConst() {
		
		long left = getLeftOperand().calcuConst();
		long right = getRightOperand().calcuConst();

		if(this instanceof AddExpr)
			return CFMap.add(left, right);
		if(this instanceof SubExpr)
			return CFMap.sub(left, right);
		if(this instanceof MulExpr)
			return CFMap.mul(left, right);
		if(this instanceof DivExpr)
			return CFMap.div(left, right);
		if(this instanceof ModExpr)
			return CFMap.mod(left, right);
		throw new Error("ArithmeticExpr.calcuConst()");
				
	}
	
	
	eq PreIncExpr.calcuConst() {
		long val = getOperand().calcuConst();
		if(val == CFMap.NAC || val == CFMap.UNDEF)
			return val;			
		return ++val;
	}
	
	eq PreDecExpr.calcuConst() {
		long val = getOperand().calcuConst();
		if(val == CFMap.NAC || val == CFMap.UNDEF)
			return val;			
		return --val;
	}
	
	eq PostfixExpr.calcuConst() = getOperand().calcuConst();


	
	eq ParExpr.calcuConst() = getExpr().calcuConst();
	//eq CastExpr.calcuConst() = getExpr().calcuConst();
	eq CastExpr.calcuConst() = CFMap.NAC;
	eq Dot.calcuConst() = CFMap.NAC;
	
	eq ShiftExpr.calcuConst() = CFMap.NAC;
	eq BitwiseExpr.calcuConst() = CFMap.NAC;
	

	
  	
	
  	
  	// useless comparison
  	syn boolean RelationalExpr.constUselessComparison() {
  		Object left = getLeftOperand();
  		Object right = getRightOperand();
  		
  		boolean l = false;
  		boolean r = false;
  		//left
  		if(left instanceof Literal)
  			l = true;
  		else if(left instanceof VarAccess && 
  				in_cf().get(((VarAccess)left).decl()) != null){
  			long leftVal = (Long)in_cf().get(((VarAccess)left).decl());
  			if(leftVal != CFMap.NAC && leftVal != CFMap.UNDEF)
  				l = true;
  		}
  		//right
 		if(right instanceof Literal)
  			r = true;
  		else if(right instanceof VarAccess && 
  				in_cf().get(((VarAccess)right).decl()) != null){
  			long rightVal = (Long)in_cf().get(((VarAccess)right).decl());
  			if(rightVal != CFMap.NAC && rightVal != CFMap.UNDEF)
  				r = true;
  		}
 		
 		//System.out.println(this);
 		//
 		if(l && r) {
 			System.err.println(this);
  			System.err.println("Source_File: "+sourceFile());
  			System.err.println("Line_Number: "+lineNumber()+"\n");
  			return true;
  		}
  		else
  			return false;
  			 			 			
  	}
  	
  	
	// Collect dead code in each compilation unit
	coll HashSet CompilationUnit.constUselessCode() [new HashSet()] with add root CompilationUnit;
	RelationalExpr contributes this when constUselessComparison() 
		to CompilationUnit.constUselessCode() for enclosingCompilationUnit();
	
  	
}