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package org.checkerframework.dataflow.constantpropagation;
import java.util.List;
import org.checkerframework.dataflow.analysis.ConditionalTransferResult;
import org.checkerframework.dataflow.analysis.RegularTransferResult;
import org.checkerframework.dataflow.analysis.TransferFunction;
import org.checkerframework.dataflow.analysis.TransferInput;
import org.checkerframework.dataflow.analysis.TransferResult;
import org.checkerframework.dataflow.cfg.UnderlyingAST;
import org.checkerframework.dataflow.cfg.node.AbstractNodeVisitor;
import org.checkerframework.dataflow.cfg.node.AssignmentNode;
import org.checkerframework.dataflow.cfg.node.EqualToNode;
import org.checkerframework.dataflow.cfg.node.IntegerLiteralNode;
import org.checkerframework.dataflow.cfg.node.LocalVariableNode;
import org.checkerframework.dataflow.cfg.node.Node;
import com.sun.tools.javac.tree.JCTree.JCIdent;
public class ConstantPropagationTransfer
extends
AbstractNodeVisitor<TransferResult<Constant, ConstantPropagationStore>, TransferInput<Constant, ConstantPropagationStore>>
implements TransferFunction<Constant, ConstantPropagationStore> {
@Override
public ConstantPropagationStore initialStore(UnderlyingAST underlyingAST,
List<LocalVariableNode> parameters) {
ConstantPropagationStore store = new ConstantPropagationStore();
return store;
}
@Override
public TransferResult<Constant, ConstantPropagationStore> visitLocalVariable(
LocalVariableNode node, TransferInput<Constant, ConstantPropagationStore> before) {
ConstantPropagationStore store = before.getRegularStore();
Constant value = store.getInformation(node);
return new RegularTransferResult<>(value, store);
}
@Override
public TransferResult<Constant, ConstantPropagationStore> visitNode(Node n,
TransferInput<Constant, ConstantPropagationStore> p) {
return new RegularTransferResult<>(null, p.getRegularStore());
}
@Override
public TransferResult<Constant, ConstantPropagationStore> visitAssignment(
AssignmentNode n,
TransferInput<Constant, ConstantPropagationStore> pi) {
ConstantPropagationStore p = pi.getRegularStore();
Node target = n.getTarget();
Constant info = null;
if (target instanceof LocalVariableNode) {
LocalVariableNode t = (LocalVariableNode) target;
info = p.getInformation(n.getExpression());
p.setInformation(t, info);
}
return new RegularTransferResult<>(info, p);
}
@Override
public TransferResult<Constant, ConstantPropagationStore> visitIntegerLiteral(
IntegerLiteralNode n,
TransferInput<Constant, ConstantPropagationStore> pi) {
ConstantPropagationStore p = pi.getRegularStore();
Constant c = new Constant(n.getValue());
p.setInformation(n, c);
return new RegularTransferResult<>(c, p);
}
@Override
public TransferResult<Constant, ConstantPropagationStore> visitEqualTo(
EqualToNode n, TransferInput<Constant, ConstantPropagationStore> pi) {
ConstantPropagationStore p = pi.getRegularStore();
ConstantPropagationStore old = p.copy();
Node left = n.getLeftOperand();
Node right = n.getRightOperand();
process(p, left, right);
process(p, right, left);
return new ConditionalTransferResult<>(null, p, old);
}
protected void process(ConstantPropagationStore p, Node a, Node b) {
Constant val = p.getInformation(a);
if (b instanceof LocalVariableNode && val.isConstant()) {
p.setInformation(b, val);
}
}
}
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