I think gdb might be able to be coaxed into doing it in a statically linked binary (as is normal for embedded)
although, I seem to recall it not really handling rust types very well
```
ptype /o MyStruct

type = struct MyStruct {
    /* offset | size */ int a;    /* 0 | 4 */
    /* offset | size */ char b;   /* 4 | 1 */
    /* offset | size */ int c;    /* 8 | 4 */
    /* total size (bytes): 12 */
}
```

I guess there are several different variables:
* the size/alignment of the overall struct
* the size/alignment of each struct field