Displays the names of local variables, method arguments and method return values in IDA Pro. (NativeAOT) #117309

Hi. I am dealing with the problem of mapping local variables and arguments with returned arguments at functions in IDA Pro. That is, type mapping.

My goal is that when I load a binary into IDA Pro, it will automatically get all the type information it needs in a .pdb file, without having to manually convert pointers to structures from the developer. For example:

What's happening now:

public class Person
{
    public int Id { get; set; }
    public int Age { get; set; }
    public string Name { get; set; }
}

internal class Program
{
    static void Main(string[] args)
    {
        Person person = new Person
        {
            Id = 1,
            Name = "Test",
            Age = 15
        };

        PrintPersonAge(person);
    }

    [MethodImpl(MethodImplOptions.NoInlining)]
    private static void PrintPersonAge(Person person)
    {
        Console.WriteLine(person.Age);
    }
}

In the decompiled version from IDA, the arguments are not automatically inserted, although they are specified in Local Types.

repro_Program__PrintPersonAge proc near

var_8= byte ptr -8

push    rbp
push    rdi
sub     rsp, 28h
lea     rbp, [rsp+38h+var_8]
mov     [rbp+10h], rcx
nop
mov     rcx, [rbp+10h]
call    repro_Person__get_Age
mov     [rbp-0Ch], eax
mov     ecx, [rbp-0Ch]
call    System_Console_System_Console__WriteLine_7
nop
nop
add     rsp, 28h
pop     rdi
pop     rbp
retn
repro_Program__PrintPersonAge endp

I decided to use cvdump.exe to see what data is generated, and saw a strange thing:

The type of the process was not specified. I decided to find out what the problem was and it was because the methodTypeIndex variable was not used in the EmitSubprogramInfo method in the “ILCompiler.Compiler\Compiler\ObjectWriter\CodeView\CodeViewSymbolsBuilder.cs” file.

I made the variable write but an additional problem appeared. In the following dump I saw this:


The reference pointed to a completely empty forward ref type, when the full type was under a completely different number:

BUT! Some structures and classes are successfully caught by IDA Pro and shown in the disassembler. That is, after my change, this structure arguments were successfully inserted automatically.

I think the problem is in the file "ILCompiler.Compiler\Compiler\UserDefinedTypeDescriptor.cs" and it has something to do with:

 private Dictionary<TypeDesc, uint> _knownTypes = new Dictionary<TypeDesc, uint>();
 private Dictionary<TypeDesc, uint> _completeKnownTypes = new Dictionary<TypeDesc, uint>();

Most likely, an empty copy of the class is generated initially, so methodTypeIndex may point to it, but I could be wrong. I would be grateful if you could look into this problem.