f7d8f5b1e1
interpret: Fix writing uninit to an allocation When calling `mark_init`, we need to also be mindful of what happens with the relocations! Specifically, when we de-init memory, we need to clear relocations in that range as well or else strange things will happen (and printing will not show the de-init, since relocations take precedence there). Fixes https://github.com/rust-lang/miri/issues/2068. Here's the Miri testcase that this fixes (requires `-Zmiri-disable-validation`): ```rust use std::mem::MaybeUninit; fn main() { unsafe { let mut x = MaybeUninit::<i64>::uninit(); // Put in a ptr. x.as_mut_ptr().cast::<&i32>().write_unaligned(&0); // Overwrite parts of that pointer with 'uninit' through a Scalar. let ptr = x.as_mut_ptr().cast::<i32>(); *ptr = MaybeUninit::uninit().assume_init(); // Reading this back should hence work fine. let _c = *ptr; } } ``` Previously this failed with ``` error: unsupported operation: unable to turn pointer into raw bytes --> ../miri/uninit.rs:11:14 | 11 | let _c = *ptr; | ^^^^ unable to turn pointer into raw bytes | = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support = note: inside `main` at ../miri/uninit.rs:11:14 ``` |
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