dataflow.src.org.checkerframework.dataflow.constantpropagation.ConstantPropagationStore Maven / Gradle / Ivy
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The Checker Framework enhances Java’s type system to
make it more powerful and useful. This lets software developers
detect and prevent errors in their Java programs.
The Checker Framework includes compiler plug-ins ("checkers")
that find bugs or verify their absence. It also permits you to
write your own compiler plug-ins.
package org.checkerframework.dataflow.constantpropagation;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import org.checkerframework.dataflow.analysis.FlowExpressions;
import org.checkerframework.dataflow.analysis.Store;
import org.checkerframework.dataflow.cfg.CFGVisualizer;
import org.checkerframework.dataflow.cfg.node.IntegerLiteralNode;
import org.checkerframework.dataflow.cfg.node.LocalVariableNode;
import org.checkerframework.dataflow.cfg.node.Node;
import org.checkerframework.dataflow.constantpropagation.Constant.Type;
public class ConstantPropagationStore implements
Store {
/** Information about variables gathered so far. */
Map contents;
public ConstantPropagationStore() {
contents = new HashMap<>();
}
protected ConstantPropagationStore(Map contents) {
this.contents = contents;
}
public Constant getInformation(Node n) {
if (contents.containsKey(n)) {
return contents.get(n);
}
return new Constant(Type.TOP);
}
public void mergeInformation(Node n, Constant val) {
Constant value;
if (contents.containsKey(n)) {
value = val.leastUpperBound(contents.get(n));
} else {
value = val;
}
// TODO: remove (only two nodes supported atm)
assert n instanceof IntegerLiteralNode
|| n instanceof LocalVariableNode;
contents.put(n, value);
}
public void setInformation(Node n, Constant val) {
// TODO: remove (only two nodes supported atm)
assert n instanceof IntegerLiteralNode
|| n instanceof LocalVariableNode;
contents.put(n, val);
}
@Override
public ConstantPropagationStore copy() {
return new ConstantPropagationStore(new HashMap<>(contents));
}
@Override
public ConstantPropagationStore leastUpperBound(
ConstantPropagationStore other) {
Map newContents = new HashMap<>();
// go through all of the information of the other class
for (Entry e : other.contents.entrySet()) {
Node n = e.getKey();
Constant otherVal = e.getValue();
if (contents.containsKey(n)) {
// merge if both contain information about a variable
newContents.put(n, otherVal.leastUpperBound(contents.get(n)));
} else {
// add new information
newContents.put(n, otherVal);
}
}
for (Entry e : contents.entrySet()) {
Node n = e.getKey();
Constant thisVal = e.getValue();
if (!other.contents.containsKey(n)) {
// add new information
newContents.put(n, thisVal);
}
}
return new ConstantPropagationStore(newContents);
}
@Override
public boolean equals(Object o) {
if (o == null) {
return false;
}
if (!(o instanceof ConstantPropagationStore)) {
return false;
}
ConstantPropagationStore other = (ConstantPropagationStore) o;
// go through all of the information of the other object
for (Entry e : other.contents.entrySet()) {
Node n = e.getKey();
Constant otherVal = e.getValue();
if (otherVal.isBottom()) {
continue; // no information
}
if (contents.containsKey(n)) {
if (!otherVal.equals(contents.get(n))) {
return false;
}
} else {
return false;
}
}
// go through all of the information of the this object
for (Entry e : contents.entrySet()) {
Node n = e.getKey();
Constant thisVal = e.getValue();
if (thisVal.isBottom()) {
continue; // no information
}
if (other.contents.containsKey(n)) {
continue;
} else {
return false;
}
}
return true;
}
@Override
public int hashCode() {
int s = 0;
for (Entry e : contents.entrySet()) {
if (!e.getValue().isBottom()) {
s += e.hashCode();
}
}
return s;
}
@Override
public String toString() {
// only output local variable information
Map smallerContents = new HashMap<>();
for (Entry e : contents.entrySet()) {
if (e.getKey() instanceof LocalVariableNode) {
smallerContents.put(e.getKey(), e.getValue());
}
}
return smallerContents.toString();
}
@Override
public boolean canAlias(FlowExpressions.Receiver a,
FlowExpressions.Receiver b) {
return true;
}
@Override
public void visualize(CFGVisualizer viz) {
// Do nothing since ConstantPropagationStore doesn't support visualize
}
}