src/third_party/mozjs-45/js/src/devtools/rootAnalysis/CFG.js

/* -*- indent-tabs-mode: nil; js-indent-level: 4 -*- */

"use strict";

var functionBodies;

function findAllPoints(blockId)
{
    var points = [];
    var body;

    for (var xbody of functionBodies) {
        if (sameBlockId(xbody.BlockId, blockId)) {
            assert(!body);
            body = xbody;
        }
    }
    assert(body);

    if (!("PEdge" in body))
        return;
    for (var edge of body.PEdge) {
        points.push([body, edge.Index[0]]);
        if (edge.Kind == "Loop")
            Array.prototype.push.apply(points, findAllPoints(edge.BlockId));
    }

    return points;
}

function isMatchingDestructor(constructor, edge)
{
    if (edge.Kind != "Call")
        return false;
    var callee = edge.Exp[0];
    if (callee.Kind != "Var")
        return false;
    var variable = callee.Variable;
    assert(variable.Kind == "Func");
    if (!/::~/.test(variable.Name[0]))
        return false;

    var constructExp = constructor.PEdgeCallInstance.Exp;
    assert(constructExp.Kind == "Var");

    var destructExp = edge.PEdgeCallInstance.Exp;
    if (destructExp.Kind != "Var")
        return false;

    return sameVariable(constructExp.Variable, destructExp.Variable);
}

// Return all calls within the RAII scope of the constructor matched by
// isConstructor()
function allRAIIGuardedCallPoints(body, isConstructor)
{
    if (!("PEdge" in body))
        return [];

    var points = [];

    for (var edge of body.PEdge) {
        if (edge.Kind != "Call")
            continue;
        var callee = edge.Exp[0];
        if (callee.Kind != "Var")
            continue;
        var variable = callee.Variable;
        assert(variable.Kind == "Func");
        if (!isConstructor(variable.Name[0]))
            continue;
        if (edge.PEdgeCallInstance.Exp.Kind != "Var")
            continue;

        Array.prototype.push.apply(points, pointsInRAIIScope(body, edge));
    }

    return points;
}

// Test whether the given edge is the constructor corresponding to the given
// destructor edge
function isMatchingConstructor(destructor, edge)
{
    if (edge.Kind != "Call")
        return false;
    var callee = edge.Exp[0];
    if (callee.Kind != "Var")
        return false;
    var variable = callee.Variable;
    if (variable.Kind != "Func")
        return false;
    var name = readable(variable.Name[0]);
    var destructorName = readable(destructor.Exp[0].Variable.Name[0]);
    var match = destructorName.match(/^(.*?::)~(\w+)\(/);
    if (!match) {
        printErr("Unhandled destructor syntax: " + destructorName);
        return false;
    }
    var constructorSubstring = match[1] + match[2];
    if (name.indexOf(constructorSubstring) == -1)
        return false;

    var destructExp = destructor.PEdgeCallInstance.Exp;
    assert(destructExp.Kind == "Var");

    var constructExp = edge.PEdgeCallInstance.Exp;
    if (constructExp.Kind != "Var")
        return false;

    return sameVariable(constructExp.Variable, destructExp.Variable);
}

function findMatchingConstructor(destructorEdge, body)
{
    var worklist = [destructorEdge];
    var predecessors = getPredecessors(body);
    while(worklist.length > 0) {
        var edge = worklist.pop();
        if (isMatchingConstructor(destructorEdge, edge))
            return edge;
        if (edge.Index[0] in predecessors) {
            for (var e of predecessors[edge.Index[0]])
                worklist.push(e);
        }
    }
    printErr("Could not find matching constructor!");
    debugger;
}

function pointsInRAIIScope(body, constructorEdge) {
    var seen = {};
    var worklist = [constructorEdge.Index[1]];
    var points = [];
    while (worklist.length) {
        var point = worklist.pop();
        if (point in seen)
            continue;
        seen[point] = true;
        points.push([body, point]);
        var successors = getSuccessors(body);
        if (!(point in successors))
            continue;
        for (var nedge of successors[point]) {
            if (isMatchingDestructor(constructorEdge, nedge))
                continue;
            if (nedge.Kind == "Loop")
                Array.prototype.push.apply(points, findAllPoints(nedge.BlockId));
            worklist.push(nedge.Index[1]);
        }
    }

    return points;
}