Can i conveniently compile bytes into a Rust program with a specific alignment?

2

I didn't notice anything along the lines of this in your listed attempts. I'm not sure if this is a 100% guarantee, but it may serve as a starting point (this is simple enough to wrap with macro_rules!):

(edit: incorporated @cuviper's slick suggestion)

// This struct is generic in Bytes to admit unsizing coercions.
#[repr(C)] // guarantee 'bytes' comes after '_align'
struct AlignedTo<Align, Bytes: ?Sized> {
    _align: [Align; 0],
    bytes: Bytes, 
}

// dummy static used to create aligned data
static ALIGNED: &'static AlignedTo<f32, [u8]> = &AlignedTo {
    _align: [],
    bytes: *include_bytes!("data.dat"),
};

static ALIGNED_BYTES: &'static [u8] = &ALIGNED.bytes;

Addendum 2020-03-06

Since this has been receiving more attention, here's a macro so that you don't have to manually construct the dummy static:

#[macro_use]
mod macros {
    #[repr(C)] // guarantee 'bytes' comes after '_align'
    pub struct AlignedAs<Align, Bytes: ?Sized> {
        pub _align: [Align; 0],
        pub bytes: Bytes,
    }

    macro_rules! include_bytes_align_as {
        ($align_ty:ty, $path:literal) => {
            {  // const block expression to encapsulate the static
                use $crate::macros::AlignedAs;
                
                // this assignment is made possible by CoerceUnsized
                static ALIGNED: &AlignedAs::<$align_ty, [u8]> = &AlignedAs {
                    _align: [],
                    bytes: *include_bytes!($path),
                };
    
                &ALIGNED.bytes
            }
        };
    }
}

#[repr(align(4096))]
struct Align4096;

static A: &'static [u8] = include_bytes!("boxed.rs");
static B: &'static [u8] = include_bytes_align_as!(f64, "boxed.rs");
static C: &'static [u8] = include_bytes_align_as!(Align4096, "boxed.rs");
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