files = args.filenames
    else:
        for root, dirs, walkfiles in os.walk(args.rootdir):
            # don't visit certain dirs. This is just a performance improvement
            # as we would prune these later in normalize_files(). But doing it
            # cuts down the amount of filesystem walking we do and cuts down
            # the size of the file list
            for dname in skipped_names:

        fileTree.visit(fileVisitor)
        visited
    }

    @Override
    protected List<String> walkDirForPaths(DirectorySnapshotter walker, File rootDir, PatternSet patternSet) {
        def snapshot = walker.snapshot(rootDir.absolutePath, directoryWalkerPredicate(patternSet), [:], completeSnapshotConsumer)
        return SnapshotVisitorUtil.getAbsolutePaths(snapshot)
    }

	var stack []int
	seen := make([]bool, len(check.mono.vertices))

	// We have a path that contains a cycle and ends at v, but v may
	// only be reachable from the cycle, not on the cycle itself. We
	// start by walking backwards along the path until we find a vertex
	// that appears twice.
	for !seen[v] {
		stack = append(stack, v)
		seen[v] = true
		v = check.mono.edges[check.mono.vertices[v].pre].src
	}

		}

		// Walk backwards looking for dead stores. Keep track of shadowed addresses.
		// A "shadowed address" is a pointer, offset, and size describing a memory region that
		// is known to be written. We keep track of shadowed addresses in the shadowed map,
		// mapping the ID of the address to a shadowRange where future writes will happen.
		// Since we're walking backwards, writes to a shadowed region are useless,

            }
        }
    }

    private static void updateSubModules(Git git) throws IOException, GitAPIException {
        try (SubmoduleWalk walker = SubmoduleWalk.forIndex(git.getRepository())) {
            while (walker.next()) {
                try (Repository submodule = walker.getRepository()) {
                    if (submodule != null) {
                        Git submoduleGit = Git.wrap(submodule);

	var stack []int
	seen := make([]bool, len(check.mono.vertices))

	// We have a path that contains a cycle and ends at v, but v may
	// only be reachable from the cycle, not on the cycle itself. We
	// start by walking backwards along the path until we find a vertex
	// that appears twice.
	for !seen[v] {
		stack = append(stack, v)
		seen[v] = true
		v = check.mono.edges[check.mono.vertices[v].pre].src
	}

	if as.X != nil && as.Y != nil {
		return convas(as, init)
	}
	return as
}

// walkAssignDotType walks an OAS2DOTTYPE node.
func walkAssignDotType(n *ir.AssignListStmt, init *ir.Nodes) ir.Node {
	walkExprListSafe(n.Lhs, init)
	n.Rhs[0] = walkExpr(n.Rhs[0], init)
	return n
}

// walkAssignFunc walks an OAS2FUNC node.
func walkAssignFunc(init *ir.Nodes, n *ir.AssignListStmt) ir.Node {
	init.Append(ir.TakeInit(n)...)

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// IR visitors for walking the IR tree.
//
// The lowest level helpers are DoChildren and EditChildren, which
// nodes help implement and provide control over whether and when
// recursion happens during the walk of the IR.
//
// Although these are both useful directly, two simpler patterns
// are fairly common and also provided: Visit and Any.

// resolveFwdRefs links all FwdRef uses up to their nearest dominating definition.
func (s *phiState) resolveFwdRefs() {
	// Do a depth-first walk of the dominator tree, keeping track
	// of the most-recently-seen value for each variable.

	// Map from variable ID to SSA value at the current point of the walk.
	values := make([]*ssa.Value, len(s.varnum))
	for i := range values {
		values[i] = s.placeholder
	}

	// Stack of work to do.

	r := ir.NewBlockStmt(base.Pos, nil)
	r.List = calls
	return walkStmt(typecheck.Stmt(r))
}

// walkRecoverFP walks an ORECOVERFP node.
func walkRecoverFP(nn *ir.CallExpr, init *ir.Nodes) ir.Node {
	return mkcall("gorecover", nn.Type(), init, walkExpr(nn.Args[0], init))
}

// walkUnsafeData walks an OUNSAFESLICEDATA or OUNSAFESTRINGDATA expression.
func walkUnsafeData(n *ir.UnaryExpr, init *ir.Nodes) ir.Node {