bjoernager/rust
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don't do any work towards ptr provenance in const mode

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This commit is contained in:
Ralf Jung 2018-10-17 17:36:26 +02:00
parent 2af11f7433
commit c885d8b41e
4 changed files with 13 additions and 5 deletions
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1
src/librustc_mir/const_eval.rs
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@ -348,6 +348,7 @@ impl<'a, 'mir, 'tcx> interpret::Machine<'a, 'mir, 'tcx>
type MemoryMap = FxHashMap<AllocId, (MemoryKind<!>, Allocation)>;
const STATIC_KIND: Option<!> = None; // no copying of statics allowed
const ENABLE_PTR_TRACKING_HOOKS: bool = false; // we don't have no provenance
#[inline(always)]
fn enforce_validity(_ecx: &EvalContext<'a, 'mir, 'tcx, Self>) -> bool {

4
src/librustc_mir/interpret/cast.rs
View file

@ -47,7 +47,9 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
Misc => {
let src = self.read_value(src)?;
if src.layout.ty.is_region_ptr() && dest.layout.ty.is_unsafe_ptr() {
if M::ENABLE_PTR_TRACKING_HOOKS &&
src.layout.ty.is_region_ptr() && dest.layout.ty.is_unsafe_ptr()
{
// For the purpose of the "ptr tag hooks", treat this as creating
// a new, raw reference.
let place = self.ref_to_mplace(src)?;

5
src/librustc_mir/interpret/machine.rs
View file

@ -101,6 +101,11 @@ pub trait Machine<'a, 'mir, 'tcx>: Sized {
/// that is added to the memory so that the work is not done twice.
const STATIC_KIND: Option<Self::MemoryKinds>;
/// As an optimization, you can prevent the pointer tracking hooks from ever being
/// called. You should only do this if you do not care about provenance tracking.
/// This controls the `tag_reference` and `tag_dereference` hooks.
const ENABLE_PTR_TRACKING_HOOKS: bool;
/// Whether to enforce the validity invariant
fn enforce_validity(ecx: &EvalContext<'a, 'mir, 'tcx, Self>) -> bool;

8
src/librustc_mir/interpret/place.rs
View file

@ -265,12 +265,12 @@ where
val: ValTy<'tcx, M::PointerTag>,
) -> EvalResult<'tcx, MPlaceTy<'tcx, M::PointerTag>> {
let ptr = match val.to_scalar_ptr()? {
Scalar::Ptr(ptr) => {
Scalar::Ptr(ptr) if M::ENABLE_PTR_TRACKING_HOOKS => {
// Machine might want to track the `*` operator
let tag = M::tag_dereference(self, ptr, val.layout.ty)?;
Scalar::Ptr(Pointer::new_with_tag(ptr.alloc_id, ptr.offset, tag))
}
scalar @ Scalar::Bits { .. } => scalar,
other => other,
};
let pointee_type = val.layout.ty.builtin_deref(true).unwrap().ty;
@ -294,14 +294,14 @@ where
borrow_kind: Option<mir::BorrowKind>,
) -> EvalResult<'tcx, Value<M::PointerTag>> {
let ptr = match place.ptr {
Scalar::Ptr(ptr) => {
Scalar::Ptr(ptr) if M::ENABLE_PTR_TRACKING_HOOKS => {
// Machine might want to track the `&` operator
let (size, _) = self.size_and_align_of_mplace(place)?
.expect("create_ref cannot determine size");
let tag = M::tag_reference(self, ptr, place.layout.ty, size, borrow_kind)?;
Scalar::Ptr(Pointer::new_with_tag(ptr.alloc_id, ptr.offset, tag))
},
scalar @ Scalar::Bits { .. } => scalar,
other => other,
};
Ok(match place.meta {
None => Value::Scalar(ptr.into()),