@eagleoutice/flowr/control-flow/cfg-to-basic-blocks.js

Static Dataflow Analyzer and Program Slicer for the R Programming Language

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.convertCfgToBasicBlocks = convertCfgToBasicBlocks;
const control_flow_graph_1 = require("./control-flow-graph");
/** if true, return the target */
function singleOutgoingFd(outgoing) {
    if (!outgoing || outgoing.size !== 1) {
        return undefined;
    }
    const next = outgoing.entries().next().value;
    if (next?.[1].label === 0 /* CfgEdgeType.Fd */) {
        return next[0];
    }
    else {
        return undefined;
    }
}
/**
 * Take a control flow information of a graph without any basic blocks and convert it to a graph with basic blocks.
 */
function convertCfgToBasicBlocks(cfInfo) {
    const newCfg = wrapEveryVertexInBasicBlock(cfInfo.graph);
    if (!newCfg) {
        return cfInfo;
    }
    for (const [id, vtx] of newCfg.vertices(false)) {
        if (vtx.type !== control_flow_graph_1.CfgVertexType.Block) {
            continue;
        }
        const outgoing = newCfg.outgoingEdges(id);
        const target = singleOutgoingFd(outgoing);
        if (target) {
            const targetIn = newCfg.ingoingEdges(target);
            if (targetIn && targetIn.size === 1) {
                newCfg.mergeTwoBasicBlocks(id, target);
            }
        }
        const ingoing = newCfg.ingoingEdges(id);
        const ingoingTarget = singleOutgoingFd(ingoing);
        if (ingoingTarget) {
            const ingoingOut = newCfg.outgoingEdges(ingoingTarget);
            if (ingoingOut && ingoingOut.size === 1) {
                newCfg.mergeTwoBasicBlocks(ingoingTarget, id);
            }
        }
    }
    const findEntries = cfInfo.entryPoints.map(e => newCfg.getBasicBlock(e)?.id);
    const findExits = cfInfo.exitPoints.map(e => newCfg.getBasicBlock(e)?.id);
    if (findEntries.some(f => f === undefined) || findExits.some(f => f === undefined)) {
        /* something went wrong */
        return cfInfo;
    }
    return {
        ...cfInfo,
        graph: newCfg,
        entryPoints: findEntries,
        exitPoints: findExits,
    };
}
/** only returns undefined when the cfg already contains basic blocks */
function wrapEveryVertexInBasicBlock(existing) {
    const newGraph = new control_flow_graph_1.ControlFlowGraph();
    for (const [id, vertex] of existing.vertices(false)) {
        if (vertex.type === control_flow_graph_1.CfgVertexType.Block) {
            return undefined;
        }
        newGraph.addVertex({
            type: control_flow_graph_1.CfgVertexType.Block,
            elems: [vertex],
            id: 'bb-' + id,
        });
    }
    // promote all edges
    for (const [from, outgoing] of existing.edges().entries()) {
        for (const [to, edge] of outgoing.entries()) {
            newGraph.addEdge('bb-' + from, 'bb-' + to, edge);
        }
    }
    return newGraph;
}
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