Example of using the Roslyn Control Flow Analysis API

ControlFlow.cs

using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using System;
using System.Linq;

namespace ConsoleRoslyn
{
    class Program
    {
        static void ProcessExample(String rawCode)
        {
            SyntaxTree code = CSharpSyntaxTree.ParseText(rawCode);
            MetadataReference corLib = MetadataReference.CreateFromAssembly(typeof(object).Assembly);
            CSharpCompilation compilation = CSharpCompilation.Create("TestCompilation",
                                                                     new[] { code },
                                                                     new[] { corLib });

            SemanticModel semanticModel = compilation.GetSemanticModel(code);

            CatchClauseSyntax theCatch = code.GetRoot().DescendantNodes().OfType<CatchClauseSyntax>().First();
            ControlFlowAnalysis result = semanticModel.AnalyzeControlFlow(theCatch.Block);

            Console.WriteLine("=======================================================================");
            Console.WriteLine("{0}", theCatch.Block.ToString());
            Console.WriteLine("Succeeded          : {0}", result.Succeeded);
            Console.WriteLine("Return statements  : {0}", result?.ReturnStatements.Count() ?? 0);
            Console.WriteLine("Endpoint reachable : {0}", result.EndPointIsReachable);
            Console.WriteLine("Exit point count   : {0}", result?.ExitPoints.Count() ?? 0);
        }

        static void Main(string[] args)
        {
            String code = @"
using System;
using System.IO;

class SimpleThrow
{
    public void Example(Int32 i)
    {
        try
        {
            Console.WriteLine(""i = {0}"", i);
        }
        catch (FileNotFoundException)
        {
            Console.WriteLine(""Got an exception"");
            throw;
        }
    }
}
";
            ProcessExample(code);

            code = @"
using System;
using System.IO;

class EatException
{
    public void Example(Int32 i)
    {
        try
        {
            Console.WriteLine(""i = {0}"", i);
        }
        catch (FileNotFoundException)
        {
        }
    }
}
";
            ProcessExample(code);

            code = @"
using System;
using System.IO;

class EatExceptionInOneCase
{
    public void Example(Int32 i)
    {
        try
        {
            Console.WriteLine(""i = {0}"", i);
        }
        catch (FileNotFoundException)
        {
            if (i < 5)
            {
                throw;
            }
        }
    }
}
";
            ProcessExample(code);

            code = @"
class EatExceptionWithReturn
{
    public void Example(Int32 i)
    {
        try
        {
            Console.WriteLine(""i = {0}"", i);
        }
        catch (FileNotFoundException)
        {
            if (i < 5)
            {
                return;
            }
            else
            {
                throw;
            }
        }
    }
}
";
            ProcessExample(code);

            code = @"
class EatExceptionWithReturn
{
        static void Main()
        {
            try
            {
                String s = null;

                if (s.Length > 0)
                {
                    Console.WriteLine(""Too big"");
                }
    }
            catch
            {
                goto BailOut;
            }
            Console.WriteLine(""You should not see this!"");

            BailOut:
            Console.WriteLine(""Bailed!"");
        }
}
";
            ProcessExample(code);

        }
    }
}