feat: started working on dead code elimination (WIP)

src/dead_code_elimination.rs

@@ -0,0 +1,39 @@
+use crate::cfg::ControlFlowGraph;
+use petgraph::graph::NodeIndex;
+use petgraph::graph::Graph;
+
+// given a root node and a graph we delete every single graph component not connected to the root node
+
+// to keep track of the NodeIndex of the newly created node
+struct NodeDuo {
+    pub dead_index: NodeIndex,
+    pub alive_index: NodeIndex,
+}
+
+fn node_added(added_nodes: Vec, node_index: NodeIndex) -> bool {
+    for current_node in added_nodes {
+        if current_node.dead_index == node_index {
+            true
+        }
+    }
+    false
+}
+
+pub fn eliminate_dead_code(graph_dead: &ControlFlowGraph, root: NodeIndex) -> ControlFlowGraph {
+    let mut graph_alive = ControlFlowGraph::new();
+    let mut added_nodes = Vec::new(); //to improve runtime add only nodes with 2 outgoing edges
+    let mut node_stack = Vec::new(); //Nodes which neighbors haven't been added yet
+
+    //add node to graph_alive and add NodeDuo to node_stack
+    node_stack.push(NodeDuo::new(dead_index = root,
+                                 alive_index = graph_alive.add_node(graph_dead.node_weight(root))));
+
+    while let Some(current_node) = node_stack.pop() {
+        for neighbor in graph_dead.neighbors_directed(current_node.dead_index, Incoming) {
+            //if one of the neighbors has not been added yet we add it to our ControlFlowGraph
+            if !node_added(added_nodes, neighbor) {
+
+            }
+        }
+    }
+}