bjoernager/rust
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avoid an unnecessary call to Pointer::into_parts, and caution against into_pointer_or_addr

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This commit is contained in:
Ralf Jung 2022-04-18 11:48:09 -04:00
parent 3236092503
commit c83241a7f9
2 changed files with 6 additions and 3 deletions
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5
compiler/rustc_const_eval/src/interpret/memory.rs
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@ -158,8 +158,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
&self, &self,
ptr: Pointer<AllocId>, ptr: Pointer<AllocId>,
) -> InterpResult<'tcx, Pointer<M::PointerTag>> { ) -> InterpResult<'tcx, Pointer<M::PointerTag>> {
// We know `offset` is relative to the allocation, so we can use `into_parts`. let alloc_id = ptr.provenance;
let (alloc_id, offset) = ptr.into_parts();
// We need to handle `extern static`. // We need to handle `extern static`.
match self.tcx.get_global_alloc(alloc_id) { match self.tcx.get_global_alloc(alloc_id) {
Some(GlobalAlloc::Static(def_id)) if self.tcx.is_thread_local_static(def_id) => { Some(GlobalAlloc::Static(def_id)) if self.tcx.is_thread_local_static(def_id) => {
@ -171,7 +170,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
_ => {} _ => {}
} }
// And we need to get the tag. // And we need to get the tag.
Ok(M::tag_alloc_base_pointer(self, Pointer::new(alloc_id, offset))) Ok(M::tag_alloc_base_pointer(self, ptr))
} }
pub fn create_fn_alloc_ptr( pub fn create_fn_alloc_ptr(

4
compiler/rustc_middle/src/mir/interpret/pointer.rs
View file

@ -201,6 +201,10 @@ impl<Tag> From<Pointer<Tag>> for Pointer<Option<Tag>> {
} }
impl<Tag> Pointer<Option<Tag>> { impl<Tag> Pointer<Option<Tag>> {
/// Convert this pointer that *might* have a tag into a pointer that *definitely* has a tag, or
/// an absolute address.
///
/// This is rarely what you want; call `ptr_try_get_alloc_id` instead.
pub fn into_pointer_or_addr(self) -> Result<Pointer<Tag>, Size> { pub fn into_pointer_or_addr(self) -> Result<Pointer<Tag>, Size> {
match self.provenance { match self.provenance {
Some(tag) => Ok(Pointer::new(tag, self.offset)), Some(tag) => Ok(Pointer::new(tag, self.offset)),