71a11a0b10
For transmute::<T, U> we simply pointercast the destination from a U pointer to a T pointer, without providing any alignment information, thus LLVM assumes that the destination is aligned to hold a value of type T, which is not necessarily true. This can lead to LLVM emitting machine instructions that assume said alignment, and thus cause aborts. To fix this, we need to provide the actual alignment to store_operand() and in turn to store() so they can set the proper alignment information on the stores and LLVM can emit the proper machine instructions. Fixes #32947
32 lines
1.1 KiB
Rust
32 lines
1.1 KiB
Rust
// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
|
|
// file at the top-level directory of this distribution and at
|
|
// http://rust-lang.org/COPYRIGHT.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
|
|
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
|
|
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
|
|
// option. This file may not be copied, modified, or distributed
|
|
// except according to those terms.
|
|
|
|
#![feature(repr_simd, test)]
|
|
|
|
extern crate test;
|
|
|
|
#[repr(simd)]
|
|
pub struct Mu64(pub u64, pub u64, pub u64, pub u64);
|
|
|
|
fn main() {
|
|
// This ensures an unaligned pointer even in optimized builds, though LLVM
|
|
// gets enough type information to actually not mess things up in that case,
|
|
// but at the time of writing this, it's enough to trigger the bug in
|
|
// non-optimized builds
|
|
unsafe {
|
|
let memory = &mut [0u64; 8] as *mut _ as *mut u8;
|
|
let misaligned_ptr: &mut [u8; 32] = {
|
|
std::mem::transmute(memory.offset(1))
|
|
};
|
|
*misaligned_ptr = std::mem::transmute(Mu64(1, 1, 1, 1));
|
|
test::black_box(memory);
|
|
}
|
|
}
|