pub struct AddMovesForPackedDrops;
Expand description

This pass moves values being dropped that are within a packed struct to a separate local before dropping them, to ensure that they are dropped from an aligned address.

For example, if we have something like

#[repr(packed)]
struct Foo {
    dealign: u8,
    data: Vec<u8>
}

let foo = ...;

We want to call drop_in_place::<Vec<u8>> on data from an aligned address. This means we can’t simply drop foo.data directly, because its address is not aligned.

Instead, we move foo.data to a local and drop that:

    storage.live(drop_temp)
    drop_temp = foo.data;
    drop(drop_temp) -> next
next:
    storage.dead(drop_temp)

The storage instructions are required to avoid stack space blowup.

Trait Implementations§

Returns true if this pass is enabled with the current combination of compiler flags.

Auto Trait Implementations§

Blanket Implementations§

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.

Layout§

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference’s “Type Layout” chapter for details on type layout guarantees.

Size: 0 bytes