CommonAssignStatement.java

/**
 * 
 */
package dev.civl.mc.model.common.statement;

import java.util.HashSet;
import java.util.Set;

import dev.civl.mc.model.IF.CIVLSource;
import dev.civl.mc.model.IF.Scope;
import dev.civl.mc.model.IF.expression.ConditionalExpression;
import dev.civl.mc.model.IF.expression.Expression;
import dev.civl.mc.model.IF.expression.LHSExpression;
import dev.civl.mc.model.IF.expression.VariableExpression;
import dev.civl.mc.model.IF.location.Location;
import dev.civl.mc.model.IF.statement.AssignStatement;
import dev.civl.mc.model.IF.statement.Statement;
import dev.civl.mc.model.IF.variable.Variable;
import dev.civl.sarl.IF.SymbolicUniverse;

/**
 * An assignment statement.
 * 
 * @author Timothy K. Zirkel (zirkel)
 * 
 */
public class CommonAssignStatement extends CommonStatement
		implements
			AssignStatement {

	private LHSExpression lhs;
	private Expression rhs;
	private boolean isInitialization;

	/**
	 * An assignment statement.
	 * 
	 * @param source
	 *            The source location for this statement.
	 * @param lhs
	 *            The left hand side of the assignment.
	 * @param rhs
	 *            The right hand side of the assignment.
	 */
	public CommonAssignStatement(CIVLSource civlSource, Scope hscope,
			Scope lscope, Location source, Expression guard, LHSExpression lhs,
			Expression rhs, boolean isInitialization) {
		super(civlSource, hscope, lscope, source, guard);
		this.lhs = lhs;
		this.rhs = rhs;
		this.isInitialization = isInitialization;
	}

	/**
	 * @return The left hand side of the assignment.
	 */
	@Override
	public LHSExpression getLhs() {
		return lhs;
	}

	/**
	 * @return The right hand side of the assignment.
	 */
	@Override
	public Expression rhs() {
		return rhs;
	}

	@Override
	public String toString() {
		return lhs + " = " + rhs;
	}

	@Override
	public void calculateDerefs() {
		this.lhs.calculateDerefs();
		this.hasDerefs = this.lhs.hasDerefs();
		// this.rhs.calculateDerefs();
		// this.hasDerefs = this.lhs.hasDerefs() || this.rhs.hasDerefs();
	}

	@Override
	public void purelyLocalAnalysisOfVariables(Scope funcScope) {
		super.purelyLocalAnalysisOfVariables(funcScope);
		this.lhs.purelyLocalAnalysisOfVariables(funcScope);
		this.rhs.purelyLocalAnalysisOfVariables(funcScope);
	}

	/**
	 * {@inheritDoc} If this is an initialization assignment, this assignment
	 * can be considered as purely local even if the LHS variable is not purely
	 * local. For most cases, the RHS is a constant and thus the initialization
	 * of a variable would be considered as purely local.
	 */
	@Override
	public void purelyLocalAnalysis() {
		this.guard().purelyLocalAnalysis();
		this.lhs.purelyLocalAnalysis();
		this.rhs.purelyLocalAnalysis();
		if (this.isInitialization) {
			this.purelyLocal = this.guard().isPurelyLocal()
					&& this.rhs.isPurelyLocal();
		} else {
			this.purelyLocal = this.guard().isPurelyLocal()
					&& this.lhs.isPurelyLocal() && this.rhs.isPurelyLocal();
		}
	}

	@Override
	public void replaceWith(ConditionalExpression oldExpression,
			VariableExpression newExpression) {
		super.replaceWith(oldExpression, newExpression);
		if (rhs == oldExpression) {
			rhs = newExpression;
			return;
		}
		this.rhs.replaceWith(oldExpression, newExpression);
	}

	@Override
	public Statement replaceWith(ConditionalExpression oldExpression,
			Expression newExpression) {
		Expression newGuard = guardReplaceWith(oldExpression, newExpression);
		CommonAssignStatement newStatement = null;

		if (newGuard != null) {
			newStatement = new CommonAssignStatement(this.getSource(),
					this.statementScope, this.lowestScope, this.source(),
					newGuard, lhs, this.rhs, this.isInitialization);
		} else {

			LHSExpression newLhs = (LHSExpression) lhs
					.replaceWith(oldExpression, newExpression);

			if (newLhs != null) {
				newStatement = new CommonAssignStatement(this.getSource(),
						this.statementScope, this.lowestScope, this.source(),
						this.guard(), newLhs, rhs, this.isInitialization);
			} else {
				Expression newRhs = rhs.replaceWith(oldExpression,
						newExpression);

				if (newRhs != null) {
					newStatement = new CommonAssignStatement(this.getSource(),
							this.statementScope, this.lowestScope,
							this.source(), this.guard(), lhs, newRhs,
							this.isInitialization);
				}
			}
		}
		return newStatement;
	}

	@Override
	public boolean isInitialization() {
		return this.isInitialization;
	}

	@Override
	public Set<Variable> variableAddressedOf(Scope scope) {
		Set<Variable> result = new HashSet<>();
		Set<Variable> argumentResult = lhs.variableAddressedOf(scope);

		if (!this.isInitialization) {
			Variable lhsVariable = lhs.variableWritten(scope);

			if (lhsVariable != null)
				result.add(lhsVariable);
		}
		if (argumentResult != null)
			result.addAll(argumentResult);
		argumentResult = rhs.variableAddressedOf(scope);
		if (argumentResult != null)
			result.addAll(argumentResult);
		return result;
	}

	@Override
	public Set<Variable> variableAddressedOf() {
		Set<Variable> result = new HashSet<>();
		Set<Variable> argumentResult = lhs.variableAddressedOf();

		if (rhs instanceof VariableExpression) {
			if (rhs.getExpressionType().isPointerType()) {
				result.add(((VariableExpression) rhs).variable());
			}
		} else {
			if (argumentResult != null)
				result.addAll(argumentResult);
			argumentResult = rhs.variableAddressedOf();
			if (argumentResult != null)
				result.addAll(argumentResult);
		}

		return result;
	}

	@Override
	public StatementKind statementKind() {
		return StatementKind.ASSIGN;
	}

	@Override
	protected void calculateConstantValueWork(SymbolicUniverse universe) {
		this.rhs.calculateConstantValue(universe);
	}

	@Override
	public boolean containsHereWork() {
		return lhs.containsHere() || rhs.containsHere();
	}

	@Override
	public boolean equals(Object obj) {
		if (super.equals(obj)) {
			if (obj instanceof CommonAssignStatement) {
				CommonAssignStatement other = (CommonAssignStatement) obj;

				if (other.lhs.equals(lhs))
					if (other.rhs.equals(rhs))
						return other.isInitialization == isInitialization;
			}
		}
		return false;
	}

	@Override
	public Set<Variable> freeVariables() {
		Set<Variable> result = super.freeVariables();

		result.addAll(lhs.freeVariables());
		result.addAll(rhs.freeVariables());
		return result;
	}
}