bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Auto merge of #96946 - WaffleLapkin:ptr_mask, r=scottmcm

Browse source 
Add pointer masking convenience functions

This PR adds the following public API:
```rust
impl<T: ?Sized> *const T {
    fn mask(self, mask: usize) -> *const T;
}

impl<T: ?Sized> *mut T {
    fn mask(self, mask: usize) -> *const T;
}

// mod intrinsics
fn mask<T>(ptr: *const T, mask: usize) -> *const T
```
This is equivalent to `ptr.map_addr(|a| a & mask)` but also uses a cool llvm intrinsic.

Proposed in https://github.com/rust-lang/rust/pull/95643#issuecomment-1121562352

cc `@Gankra` `@scottmcm` `@RalfJung`

r? rust-lang/libs-api
This commit is contained in:
bors 2022-08-28 01:34:47 +00:00
commit 1e978a3627
10 changed files with 87 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

12
compiler/rustc_typeck/src/check/intrinsic.rs
View file

@ -105,7 +105,8 @@ pub fn intrinsic_operation_unsafety(intrinsic: Symbol) -> hir::Unsafety {
| sym::type_name
| sym::forget
| sym::black_box
| sym::variant_count => hir::Unsafety::Normal,
| sym::variant_count
| sym::ptr_mask => hir::Unsafety::Normal,
_ => hir::Unsafety::Unsafe,
}
}
@ -203,6 +204,15 @@ pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) {
],
tcx.mk_ptr(ty::TypeAndMut { ty: param(0), mutbl: hir::Mutability::Not }),
),
sym::ptr_mask => (
1,
vec![
tcx.mk_ptr(ty::TypeAndMut { ty: param(0), mutbl: hir::Mutability::Not }),
tcx.types.usize,
],
tcx.mk_ptr(ty::TypeAndMut { ty: param(0), mutbl: hir::Mutability::Not }),
),
sym::copy | sym::copy_nonoverlapping => (
1,
vec![