1 files changed, 88 insertions, 0 deletions
diff --git a/third_party/checker_framework_dataflow/java/org/checkerframework/dataflow/constantpropagation/ConstantPropagationTransfer.java b/third_party/checker_framework_dataflow/java/org/checkerframework/dataflow/constantpropagation/ConstantPropagationTransfer.java
new file mode 100644
index 0000000000..c0b2143d12
--- /dev/null
+++ b/third_party/checker_framework_dataflow/java/org/checkerframework/dataflow/constantpropagation/ConstantPropagationTransfer.java
@@ -0,0 +1,88 @@
+package org.checkerframework.dataflow.constantpropagation;
+
+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 java.util.List;
+
+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);
+        }
+    }
+
+}