[Bug] "relative_to_parent" is not working as expected

[Valeour]

Operating System

Windows

What's the issue you encountered?

When using "relative_to_parent" in conjunction with pointer_base, the offset is exactly the same as relative_to_base.

How can the issue be reproduced?

Data example:

00 00 08 00 00 00 00 00 01 00 03 00 00 00 00 00 00 00 18 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 02 03 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Pattern:

import std.ptr;

struct SecretData
{
    u16 value;
};

struct DataFinder
{
    u16 id;
    SecretData *offset : u16 [[pointer_base("std::ptr::relative_to_pointer")]];
};

struct DataFinderParent
{
    u16 id;
    SecretData *offset : u16 [[pointer_base("std::ptr::relative_to_parent")]];
};

DataFinder FirstBase @ 0x0;
DataFinderParent FirstParent @ 0x0;

DataFinder SecondBase @ 0x10;
DataFinderParent SecondParent @ 0x10;

Both outputs are the same, where as DataFinderParent First and Second I would expect to point to 0x8 and 0x28 respectively.

ImHex Version

1.37.4

ImHex Build Type

• Nightly or built from sources

Installation type

MSI/Installer

Additional context?

Creating a custom pointer_base method that uses addressof(parent.parent) produces expected results.

fn relative_to_parent(u128 offset) {
    return addressof(parent.parent);
};

My assumption is that the parent is returning the variable itself, not the parent structure.
Is this intentional and I've misunderstood the use of relative_to_parent?
I'm uncertain as it produces the same results as relative_to_pointer.

[paxcut]

This is a problem that has been known for a long time now. There is a bug in the parent evaluation that adds an extra scope when special functions like the format function is called. The workaround until it gets fixed is exactly what you found. Create your own relative to parent function that uses 2 parents.

[Valeour]

Alright, I did wonder. I did a search for "relative_to_parent" in the issues and didn't find anything, so hopefully this can at least help serve that purpose.

Thank you!