Passing Local to Method allows it to be overwritten

[martin-hughes]

The following script demonstrates this:

DefinitionBlock ("", "DSDT", 1, "RSACPI", "TESTTABL", 0xF0F0F0F0)
{
    Name(FCNT, 0)

    Method (CHEK, 2) {
        If (Arg0 != Arg1) {
            FCNT++
        }
    }

    Method (INR5, 1) {
        Arg0 = 5
    }

    Method (T5) {
        Local1 = 1
        INR5(Local1)
        CHEK (Local1, 1)
    }

    Method (MAIN, 0, NotSerialized) {
        T5()

        Return (FCNT)
    }
}

Local1 of T5 should remain as 1, instead it is overwritten in INR5.

I think this can be fixed by special-casing do_store to avoid writing back to the inner ref if target is an Arg that's anything over than a "true" reference, but I feel like I've missed something obvious?

[martin-hughes]

In fact, weirdly, sending Local0 as a reference causes it not to be overwritten - the following test also fails:

    // Insert me underneath `T5` above and call from `MAIN`
    Method (T6) {
        Local1 = 1
        INR5(RefOf(Local1))
        CHEK (Local1, 5)
    }

Both tests work with uACPI.

[martin-hughes]

Attached (store.asl.txt) is my first try of a proposed set of test-cases for this. The distinction between strings and other types is frustrating! Any thoughts from you @IsaacWoods or anyone else? (These tests all pass in uACPI)

Also the distinction between "transparent" and "real" references is a bit fiddly - I wondered @IsaacWoods if you remember why you merged the two concepts into one ObjectType (Reference), I think understanding that would help me a lot with understanding the logic of how the crate handles references.