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Use strict_provenance #18909

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Use strict_provenance #18909

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7 changes: 0 additions & 7 deletions Cargo.lock
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2 changes: 1 addition & 1 deletion Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@ exclude = ["crates/proc-macro-srv/proc-macro-test/imp"]
resolver = "2"

[workspace.package]
rust-version = "1.82"
rust-version = "1.84"
edition = "2021"
license = "MIT OR Apache-2.0"
authors = ["rust-analyzer team"]
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1 change: 0 additions & 1 deletion crates/intern/Cargo.toml
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Expand Up @@ -19,7 +19,6 @@ dashmap.workspace = true
hashbrown.workspace = true
rustc-hash.workspace = true
triomphe.workspace = true
sptr = "0.3.2"

[lints]
workspace = true
37 changes: 7 additions & 30 deletions crates/intern/src/symbol.rs
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Expand Up @@ -13,7 +13,6 @@ use std::{
use dashmap::{DashMap, SharedValue};
use hashbrown::{hash_map::RawEntryMut, HashMap};
use rustc_hash::FxHasher;
use sptr::Strict;
use triomphe::Arc;

pub mod symbols;
Expand Down Expand Up @@ -84,7 +83,7 @@ impl TaggedArcPtr {
#[inline]
pub(crate) unsafe fn try_as_arc_owned(self) -> Option<ManuallyDrop<Arc<Box<str>>>> {
// Unpack the tag from the alignment niche
let tag = Strict::addr(self.packed.as_ptr()) & Self::BOOL_BITS;
let tag = self.packed.as_ptr().addr() & Self::BOOL_BITS;
if tag != 0 {
// Safety: We checked that the tag is non-zero -> true, so we are pointing to the data offset of an `Arc`
Some(ManuallyDrop::new(unsafe {
Expand All @@ -99,40 +98,18 @@ impl TaggedArcPtr {
fn pack_arc(ptr: NonNull<*const str>) -> NonNull<*const str> {
let packed_tag = true as usize;

// can't use this strict provenance stuff here due to trait methods not being const
// unsafe {
// // Safety: The pointer is derived from a non-null
// NonNull::new_unchecked(Strict::map_addr(ptr.as_ptr(), |addr| {
// // Safety:
// // - The pointer is `NonNull` => it's address is `NonZero<usize>`
// // - `P::BITS` least significant bits are always zero (`Pointer` contract)
// // - `T::BITS <= P::BITS` (from `Self::ASSERTION`)
// //
// // Thus `addr >> T::BITS` is guaranteed to be non-zero.
// //
// // `{non_zero} | packed_tag` can't make the value zero.

// (addr >> Self::BOOL_BITS) | packed_tag
// }))
// }
// so what follows is roughly what the above looks like but inlined

let self_addr = ptr.as_ptr() as *const *const str as usize;
let addr = self_addr | packed_tag;
let dest_addr = addr as isize;
let offset = dest_addr.wrapping_sub(self_addr as isize);

// SAFETY: The resulting pointer is guaranteed to be NonNull as we only modify the niche bytes
unsafe { NonNull::new_unchecked(ptr.as_ptr().cast::<u8>().wrapping_offset(offset).cast()) }
unsafe {
// Safety: The pointer is derived from a non-null and bit-oring it with true (1) will
// not make it null.
NonNull::new_unchecked(ptr.as_ptr().map_addr(|addr| addr | packed_tag))
}
}

#[inline]
pub(crate) fn pointer(self) -> NonNull<*const str> {
// SAFETY: The resulting pointer is guaranteed to be NonNull as we only modify the niche bytes
unsafe {
NonNull::new_unchecked(Strict::map_addr(self.packed.as_ptr(), |addr| {
addr & !Self::BOOL_BITS
}))
NonNull::new_unchecked(self.packed.as_ptr().map_addr(|addr| addr & !Self::BOOL_BITS))
}
}

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