Trait rustc_const_eval::interpret::Provenance
source · [−]pub trait Provenance: Copy + Debug {
const OFFSET_IS_ADDR: bool;
const ERR_ON_PARTIAL_PTR_OVERWRITE: bool;
fn fmt(ptr: &Pointer<Self>, f: &mut Formatter<'_>) -> Result<(), Error>;
fn get_alloc_id(self) -> Option<AllocId>;
}
Expand description
This trait abstracts over the kind of provenance that is associated with a Pointer
. It is
mostly opaque; the Machine
trait extends it with some more operations that also have access to
some global state.
We don’t actually care about this Debug
bound (we use Provenance::fmt
to format the entire
pointer), but derive
adds some unnecessary bounds.
Required Associated Constants
const OFFSET_IS_ADDR: bool
const OFFSET_IS_ADDR: bool
Says whether the offset
field of Pointer
s with this provenance is the actual physical address.
If true, ptr-to-int casts work by simply discarding the provenance. If
false`, ptr-to-int casts are not supported. The offset must be relative in that case.
We also use this trait to control whether to abort execution when a pointer is being partially overwritten
(this avoids a separate trait in allocation.rs
just for this purpose).
Required Methods
Determines how a pointer should be printed.
fn get_alloc_id(self) -> Option<AllocId>
fn get_alloc_id(self) -> Option<AllocId>
If OFFSET_IS_ADDR == false
, provenance must always be able to
identify the allocation this ptr points to (i.e., this must return Some
).
Otherwise this function is best-effort (but must agree with Machine::ptr_get_alloc
).
(Identifying the offset in that allocation, however, is harder – use Memory::ptr_get_alloc
for that.)