@eagleoutice/flowr/control-flow/simple-visitor.js

Static Dataflow Analyzer and Program Slicer for the R Programming Language

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.visitCfgInReverseOrder = visitCfgInReverseOrder;
exports.visitCfgInOrder = visitCfgInOrder;
exports.canReach = canReach;
const control_flow_graph_1 = require("./control-flow-graph");
/**
 * Visit all nodes reachable from the start node in the control flow graph, traversing the dependencies but ignoring cycles.
 * @param graph     - The control flow graph.
 * @param startNodes - The nodes to start the traversal from.
 * @param visitor   - The visitor function to call for each node, if you return true the traversal from this node will be stopped.
 *
 * This function is of type {@link SimpleCfgVisitor}.
 *
 * @see {@link visitCfgInOrder} for a traversal in order
 */
function visitCfgInReverseOrder(graph, startNodes, 
// eslint-disable-next-line @typescript-eslint/no-invalid-void-type -- void is used to indicate that the return value is ignored/we never stop
visitor) {
    const visited = new Set();
    let queue = [...startNodes];
    const hasBb = graph.mayHaveBasicBlocks();
    while (queue.length > 0) {
        const current = queue.pop();
        if (visited.has(current)) {
            continue;
        }
        visited.add(current);
        if (visitor(current)) {
            continue;
        }
        else if (hasBb) {
            const get = graph.getVertex(current);
            if (get?.type === control_flow_graph_1.CfgVertexType.Block) {
                queue = queue.concat(get.elems.toReversed().map(e => e.id));
            }
        }
        const incoming = graph.outgoingEdges(current);
        if (incoming) {
            queue.push(...incoming.keys());
        }
    }
}
/**
 * Visit all nodes reachable from the start node in the control flow graph, traversing the dependencies in execution order but ignoring cycles.
 * @param graph      - The control flow graph.
 * @param startNodes - The nodes to start the traversal from.
 * @param visitor    - The visitor function to call for each node, if you return true the traversal from this node will be stopped.
 *
 * This function is of type {@link SimpleCfgVisitor}.
 *
 * @see {@link visitCfgInReverseOrder} for a traversal in reversed order
 */
function visitCfgInOrder(graph, startNodes, 
// eslint-disable-next-line @typescript-eslint/no-invalid-void-type -- void is used to indicate that the return value is ignored/we never stop
visitor) {
    const visited = new Set();
    let queue = startNodes.slice();
    const hasBb = graph.mayHaveBasicBlocks();
    while (queue.length > 0) {
        const current = queue.shift();
        if (visited.has(current)) {
            continue;
        }
        visited.add(current);
        if (visitor(current)) {
            continue;
        }
        else if (hasBb) {
            const get = graph.getVertex(current);
            if (get?.type === control_flow_graph_1.CfgVertexType.Block) {
                queue = queue.concat(get.elems.map(e => e.id));
            }
        }
        const outgoing = graph.ingoingEdges(current) ?? [];
        for (const [to] of outgoing) {
            queue.push(to);
        }
    }
}
/**
 * Check if a node can reach another node in the control flow graph.
 */
function canReach(graph, from, to) {
    let reached = false;
    visitCfgInOrder(graph, from, node => {
        if (node === to) {
            reached = true;
            return true;
        }
    });
    return reached;
}
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