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111 lines
3.2 KiB
111 lines
3.2 KiB
/*
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* Expression (c) 1998 Jochen Hoenicke
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*
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* You may distribute under the terms of the GNU General Public License.
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*
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* IN NO EVENT SHALL JOCHEN HOENICKE BE LIABLE TO ANY PARTY FOR DIRECT,
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* INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF
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* THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF JOCHEN HOENICKE
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* HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* JOCHEN HOENICKE SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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* PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS"
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* BASIS, AND JOCHEN HOENICKE HAS NO OBLIGATION TO PROVIDE MAINTENANCE,
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* SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*
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* $Id$
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*/
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package jode;
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public abstract class Expression {
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protected Type type;
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Expression parent = null;
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public Expression(Type type) {
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this.type = type;
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}
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public Type getType() {
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return type;
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}
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public void setType(Type newType) {
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this.type = newType;
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}
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public void updateType() {
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if (parent != null)
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parent.updateType();
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}
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/**
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* Get the number of operands.
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* @return The number of stack entries this expression needs.
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*/
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public abstract int getOperandCount();
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public Expression negate() {
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Operator negop =
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new UnaryOperator(Type.tBoolean, Operator.LOG_NOT_OP);
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return new ComplexExpression(negop, new Expression[] { this });
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}
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/**
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* Checks if the given Expression (which should be a StoreInstruction)
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* can be combined into this expression.
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* @param e The store expression.
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* @return 1, if it can, 0, if no match was found and -1, if a
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* conflict was found. You may wish to check for >0.
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*/
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public int canCombine(Expression e) {
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if (e instanceof ComplexExpression
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&& e.getOperator() instanceof StoreInstruction) {
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StoreInstruction store = (StoreInstruction) e.getOperator();
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if (store.matches(getOperator()))
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return 1;
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}
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return 0;
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}
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/**
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* Combines the given Expression (which should be a StoreInstruction)
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* into this expression. You must only call this if
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* canCombine returns the value 1.
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* @param e The store expression.
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* @return The combined expression.
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*/
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public Expression combine(Expression e) {
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StoreInstruction store = (StoreInstruction) e.getOperator();
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((ComplexExpression)e).operator
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= new AssignOperator(store.getOperatorIndex(), store);
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((ComplexExpression)e).type
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= this.type.intersection(store.getLValueType());
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return e;
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}
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public Expression simplify() {
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return this;
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}
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Expression simplifyStringBuffer() {
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return null;
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}
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public abstract Operator getOperator();
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public abstract String toString();
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String toString(int minPriority) {
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String result = toString();
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if (getOperator().getPriority() < minPriority)
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return "("+result+")";
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return result;
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}
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public boolean isVoid() {
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return getType() == Type.tVoid;
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}
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}
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