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Stabilize const_ptr_read

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bors 2023-05-05 12:50:59 +00:00 committed by Albin Hedman
parent 4a18324a4d
commit 81c2459af6
17 changed files with 35 additions and 42 deletions
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1
library/alloc/src/lib.rs
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@ -113,7 +113,6 @@
#![feature(const_maybe_uninit_write)]
#![feature(const_maybe_uninit_zeroed)]
#![feature(const_pin)]
#![feature(const_ptr_read)]
#![feature(const_refs_to_cell)]
#![feature(const_size_of_val)]
#![feature(const_waker)]

2
library/core/src/intrinsics.rs
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@ -2260,7 +2260,7 @@ pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) {
/// This intrinsic can *only* be called where the pointer is a local without
/// projections (`read_via_copy(ptr)`, not `read_via_copy(*ptr)`) so that it
/// trivially obeys runtime-MIR rules about derefs in operands.
#[rustc_const_unstable(feature = "const_ptr_read", issue = "80377")]
#[rustc_const_stable(feature = "const_ptr_read", since = "CURRENT_RUSTC_VERSION")]
#[rustc_nounwind]
pub fn read_via_copy<T>(ptr: *const T) -> T;

1
library/core/src/lib.rs
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@ -140,7 +140,6 @@
#![feature(const_pointer_is_aligned)]
#![feature(const_ptr_as_ref)]
#![feature(const_ptr_is_null)]
#![feature(const_ptr_read)]
#![feature(const_ptr_sub_ptr)]
#![feature(const_ptr_write)]
#![feature(const_raw_ptr_comparison)]

4
library/core/src/ptr/const_ptr.rs
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@ -1195,7 +1195,7 @@ pub const fn wrapping_byte_sub(self, count: usize) -> Self {
///
/// [`ptr::read`]: crate::ptr::read()
#[stable(feature = "pointer_methods", since = "1.26.0")]
#[rustc_const_unstable(feature = "const_ptr_read", issue = "80377")]
#[rustc_const_stable(feature = "const_ptr_read", since = "CURRENT_RUSTC_VERSION")]
#[inline]
#[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
pub const unsafe fn read(self) -> T
@ -1236,7 +1236,7 @@ pub unsafe fn read_volatile(self) -> T
///
/// [`ptr::read_unaligned`]: crate::ptr::read_unaligned()
#[stable(feature = "pointer_methods", since = "1.26.0")]
#[rustc_const_unstable(feature = "const_ptr_read", issue = "80377")]
#[rustc_const_stable(feature = "const_ptr_read", since = "CURRENT_RUSTC_VERSION")]
#[inline]
#[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
pub const unsafe fn read_unaligned(self) -> T

6
library/core/src/ptr/mod.rs
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@ -1133,7 +1133,8 @@ macro_rules! attempt_swap_as_chunks {
/// [valid]: self#safety
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_unstable(feature = "const_ptr_read", issue = "80377")]
#[rustc_const_stable(feature = "const_ptr_read", since = "CURRENT_RUSTC_VERSION")]
#[rustc_allow_const_fn_unstable(const_mut_refs, const_maybe_uninit_as_mut_ptr)]
#[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
pub const unsafe fn read<T>(src: *const T) -> T {
// It would be semantically correct to implement this via `copy_nonoverlapping`
@ -1249,7 +1250,8 @@ macro_rules! attempt_swap_as_chunks {
/// ```
#[inline]
#[stable(feature = "ptr_unaligned", since = "1.17.0")]
#[rustc_const_unstable(feature = "const_ptr_read", issue = "80377")]
#[rustc_const_stable(feature = "const_ptr_read", since = "CURRENT_RUSTC_VERSION")]
#[rustc_allow_const_fn_unstable(const_mut_refs, const_maybe_uninit_as_mut_ptr)]
#[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
pub const unsafe fn read_unaligned<T>(src: *const T) -> T {
let mut tmp = MaybeUninit::<T>::uninit();

4
library/core/src/ptr/mut_ptr.rs
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@ -1305,7 +1305,7 @@ pub const fn wrapping_byte_sub(self, count: usize) -> Self {
///
/// [`ptr::read`]: crate::ptr::read()
#[stable(feature = "pointer_methods", since = "1.26.0")]
#[rustc_const_unstable(feature = "const_ptr_read", issue = "80377")]
#[rustc_const_stable(feature = "const_ptr_read", since = "CURRENT_RUSTC_VERSION")]
#[inline(always)]
#[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
pub const unsafe fn read(self) -> T
@ -1346,7 +1346,7 @@ pub unsafe fn read_volatile(self) -> T
///
/// [`ptr::read_unaligned`]: crate::ptr::read_unaligned()
#[stable(feature = "pointer_methods", since = "1.26.0")]
#[rustc_const_unstable(feature = "const_ptr_read", issue = "80377")]
#[rustc_const_stable(feature = "const_ptr_read", since = "CURRENT_RUSTC_VERSION")]
#[inline(always)]
#[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
pub const unsafe fn read_unaligned(self) -> T

1
library/core/tests/lib.rs
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@ -18,7 +18,6 @@
#![feature(const_pointer_byte_offsets)]
#![feature(const_pointer_is_aligned)]
#![feature(const_ptr_as_ref)]
#![feature(const_ptr_read)]
#![feature(const_ptr_write)]
#![feature(const_trait_impl)]
#![feature(const_likely)]

1
src/tools/miri/tests/fail/const-ub-checks.rs
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@ -1,4 +1,3 @@
#![feature(const_ptr_read)]
const UNALIGNED_READ: () = unsafe {
let x = &[0u8; 4];

2
tests/ui/const-generics/issues/issue-105821.rs
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@ -1,7 +1,7 @@
// check-pass
#![allow(incomplete_features)]
#![feature(adt_const_params, const_ptr_read, generic_const_exprs)]
#![feature(adt_const_params, generic_const_exprs)]
#![allow(dead_code)]
const fn catone<const M: usize>(_a: &[u8; M]) -> [u8; M + 1]

2
tests/ui/const-ptr/out_of_bounds_read.rs
View File

@ -1,7 +1,5 @@
// error-pattern: evaluation of constant value failed
#![feature(const_ptr_read)]
fn main() {
use std::ptr;

6
tests/ui/const-ptr/out_of_bounds_read.stderr
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@ -6,7 +6,7 @@ error[E0080]: evaluation of constant value failed
note: inside `std::ptr::read::<u32>`
--> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
note: inside `_READ`
--> $DIR/out_of_bounds_read.rs:12:33
--> $DIR/out_of_bounds_read.rs:10:33
|
LL | const _READ: u32 = unsafe { ptr::read(PAST_END_PTR) };
| ^^^^^^^^^^^^^^^^^^^^^^^
@ -21,7 +21,7 @@ note: inside `std::ptr::read::<u32>`
note: inside `ptr::const_ptr::<impl *const u32>::read`
--> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
note: inside `_CONST_READ`
--> $DIR/out_of_bounds_read.rs:13:39
--> $DIR/out_of_bounds_read.rs:11:39
|
LL | const _CONST_READ: u32 = unsafe { PAST_END_PTR.read() };
| ^^^^^^^^^^^^^^^^^^^
@ -36,7 +36,7 @@ note: inside `std::ptr::read::<u32>`
note: inside `ptr::mut_ptr::<impl *mut u32>::read`
--> $SRC_DIR/core/src/ptr/mut_ptr.rs:LL:COL
note: inside `_MUT_READ`
--> $DIR/out_of_bounds_read.rs:14:37
--> $DIR/out_of_bounds_read.rs:12:37
|
LL | const _MUT_READ: u32 = unsafe { (PAST_END_PTR as *mut u32).read() };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

1
tests/ui/consts/const-eval/ub-ref-ptr.rs
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@ -3,7 +3,6 @@
// normalize-stderr-test "(the raw bytes of the constant) \(size: [0-9]*, align: [0-9]*\)" -> "$1 (size: $$SIZE, align: $$ALIGN)"
// normalize-stderr-test "([0-9a-f][0-9a-f] |╾─*a(lloc)?[0-9]+(\+[a-z0-9]+)?─*╼ )+ *│.*" -> "HEX_DUMP"
#![allow(invalid_value)]
#![feature(const_ptr_read)]
use std::mem;

34
tests/ui/consts/const-eval/ub-ref-ptr.stderr
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@ -1,5 +1,5 @@
error[E0080]: it is undefined behavior to use this value
--> $DIR/ub-ref-ptr.rs:16:1
--> $DIR/ub-ref-ptr.rs:15:1
|
LL | const UNALIGNED: &u16 = unsafe { mem::transmute(&[0u8; 4]) };
| ^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered an unaligned reference (required 2 byte alignment but found 1)
@ -10,7 +10,7 @@ LL | const UNALIGNED: &u16 = unsafe { mem::transmute(&[0u8; 4]) };
}
error[E0080]: it is undefined behavior to use this value
--> $DIR/ub-ref-ptr.rs:20:1
--> $DIR/ub-ref-ptr.rs:19:1
|
LL | const UNALIGNED_BOX: Box<u16> = unsafe { mem::transmute(&[0u8; 4]) };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered an unaligned box (required 2 byte alignment but found 1)
@ -21,7 +21,7 @@ LL | const UNALIGNED_BOX: Box<u16> = unsafe { mem::transmute(&[0u8; 4]) };
}
error[E0080]: it is undefined behavior to use this value
--> $DIR/ub-ref-ptr.rs:24:1
--> $DIR/ub-ref-ptr.rs:23:1
|
LL | const NULL: &u16 = unsafe { mem::transmute(0usize) };
| ^^^^^^^^^^^^^^^^ constructing invalid value: encountered a null reference
@ -32,7 +32,7 @@ LL | const NULL: &u16 = unsafe { mem::transmute(0usize) };
}
error[E0080]: it is undefined behavior to use this value
--> $DIR/ub-ref-ptr.rs:27:1
--> $DIR/ub-ref-ptr.rs:26:1
|
LL | const NULL_BOX: Box<u16> = unsafe { mem::transmute(0usize) };
| ^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a null box
@ -43,7 +43,7 @@ LL | const NULL_BOX: Box<u16> = unsafe { mem::transmute(0usize) };
}
error[E0080]: evaluation of constant value failed
--> $DIR/ub-ref-ptr.rs:34:1
--> $DIR/ub-ref-ptr.rs:33:1
|
LL | const REF_AS_USIZE: usize = unsafe { mem::transmute(&0) };
| ^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@ -52,7 +52,7 @@ LL | const REF_AS_USIZE: usize = unsafe { mem::transmute(&0) };
= help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
error[E0080]: evaluation of constant value failed
--> $DIR/ub-ref-ptr.rs:37:39
--> $DIR/ub-ref-ptr.rs:36:39
|
LL | const REF_AS_USIZE_SLICE: &[usize] = &[unsafe { mem::transmute(&0) }];
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@ -61,13 +61,13 @@ LL | const REF_AS_USIZE_SLICE: &[usize] = &[unsafe { mem::transmute(&0) }];
= help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
note: erroneous constant used
--> $DIR/ub-ref-ptr.rs:37:38
--> $DIR/ub-ref-ptr.rs:36:38
|
LL | const REF_AS_USIZE_SLICE: &[usize] = &[unsafe { mem::transmute(&0) }];
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0080]: evaluation of constant value failed
--> $DIR/ub-ref-ptr.rs:40:86
--> $DIR/ub-ref-ptr.rs:39:86
|
LL | const REF_AS_USIZE_BOX_SLICE: Box<[usize]> = unsafe { mem::transmute::<&[usize], _>(&[mem::transmute(&0)]) };
| ^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@ -76,13 +76,13 @@ LL | const REF_AS_USIZE_BOX_SLICE: Box<[usize]> = unsafe { mem::transmute::<&[us
= help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
note: erroneous constant used
--> $DIR/ub-ref-ptr.rs:40:85
--> $DIR/ub-ref-ptr.rs:39:85
|
LL | const REF_AS_USIZE_BOX_SLICE: Box<[usize]> = unsafe { mem::transmute::<&[usize], _>(&[mem::transmute(&0)]) };
| ^^^^^^^^^^^^^^^^^^^^^
error[E0080]: it is undefined behavior to use this value
--> $DIR/ub-ref-ptr.rs:43:1
--> $DIR/ub-ref-ptr.rs:42:1
|
LL | const USIZE_AS_REF: &'static u8 = unsafe { mem::transmute(1337usize) };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a dangling reference (0x539[noalloc] has no provenance)
@ -93,7 +93,7 @@ LL | const USIZE_AS_REF: &'static u8 = unsafe { mem::transmute(1337usize) };
}
error[E0080]: it is undefined behavior to use this value
--> $DIR/ub-ref-ptr.rs:46:1
--> $DIR/ub-ref-ptr.rs:45:1
|
LL | const USIZE_AS_BOX: Box<u8> = unsafe { mem::transmute(1337usize) };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a dangling box (0x539[noalloc] has no provenance)
@ -104,13 +104,13 @@ LL | const USIZE_AS_BOX: Box<u8> = unsafe { mem::transmute(1337usize) };
}
error[E0080]: evaluation of constant value failed
--> $DIR/ub-ref-ptr.rs:49:41
--> $DIR/ub-ref-ptr.rs:48:41
|
LL | const UNINIT_PTR: *const i32 = unsafe { MaybeUninit { uninit: () }.init };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
error[E0080]: it is undefined behavior to use this value
--> $DIR/ub-ref-ptr.rs:53:1
--> $DIR/ub-ref-ptr.rs:52:1
|
LL | const NULL_FN_PTR: fn() = unsafe { mem::transmute(0usize) };
| ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered null pointer, but expected a function pointer
@ -121,13 +121,13 @@ LL | const NULL_FN_PTR: fn() = unsafe { mem::transmute(0usize) };
}
error[E0080]: evaluation of constant value failed
--> $DIR/ub-ref-ptr.rs:55:38
--> $DIR/ub-ref-ptr.rs:54:38
|
LL | const UNINIT_FN_PTR: fn() = unsafe { MaybeUninit { uninit: () }.init };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
error[E0080]: it is undefined behavior to use this value
--> $DIR/ub-ref-ptr.rs:58:1
--> $DIR/ub-ref-ptr.rs:57:1
|
LL | const DANGLING_FN_PTR: fn() = unsafe { mem::transmute(13usize) };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered 0xd[noalloc], but expected a function pointer
@ -138,7 +138,7 @@ LL | const DANGLING_FN_PTR: fn() = unsafe { mem::transmute(13usize) };
}
error[E0080]: it is undefined behavior to use this value
--> $DIR/ub-ref-ptr.rs:60:1
--> $DIR/ub-ref-ptr.rs:59:1
|
LL | const DATA_FN_PTR: fn() = unsafe { mem::transmute(&13) };
| ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered alloc41, but expected a function pointer
@ -158,7 +158,7 @@ note: inside `std::ptr::read::<u32>`
note: inside `ptr::const_ptr::<impl *const u32>::read`
--> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
note: inside `UNALIGNED_READ`
--> $DIR/ub-ref-ptr.rs:67:5
--> $DIR/ub-ref-ptr.rs:66:5
|
LL | ptr.read();
| ^^^^^^^^^^

1
tests/ui/consts/extra-const-ub/detect-extra-ub.rs
View File

@ -1,7 +1,6 @@
// revisions: no_flag with_flag
// [no_flag] check-pass
// [with_flag] compile-flags: -Zextra-const-ub-checks
#![feature(const_ptr_read)]
use std::mem::transmute;

8
tests/ui/consts/extra-const-ub/detect-extra-ub.with_flag.stderr
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@ -1,11 +1,11 @@
error[E0080]: evaluation of constant value failed
--> $DIR/detect-extra-ub.rs:9:20
--> $DIR/detect-extra-ub.rs:8:20
|
LL | let _x: bool = transmute(3u8);
| ^^^^^^^^^^^^^^ constructing invalid value: encountered 0x03, but expected a boolean
error[E0080]: evaluation of constant value failed
--> $DIR/detect-extra-ub.rs:15:21
--> $DIR/detect-extra-ub.rs:14:21
|
LL | let _x: usize = transmute(&3u8);
| ^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@ -14,7 +14,7 @@ LL | let _x: usize = transmute(&3u8);
= help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
error[E0080]: evaluation of constant value failed
--> $DIR/detect-extra-ub.rs:21:30
--> $DIR/detect-extra-ub.rs:20:30
|
LL | let _x: (usize, usize) = transmute(x);
| ^^^^^^^^^^^^ unable to turn pointer into raw bytes
@ -23,7 +23,7 @@ LL | let _x: (usize, usize) = transmute(x);
= help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
error[E0080]: evaluation of constant value failed
--> $DIR/detect-extra-ub.rs:26:20
--> $DIR/detect-extra-ub.rs:25:20
|
LL | let _x: &u32 = transmute(&[0u8; 4]);
| ^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered an unaligned reference (required 4 byte alignment but found 1)

1
tests/ui/consts/issue-miri-1910.rs
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@ -1,6 +1,5 @@
// error-pattern unable to turn pointer into raw bytes
// normalize-stderr-test: "alloc[0-9]+\+0x[a-z0-9]+" -> "ALLOC"
#![feature(const_ptr_read)]
const C: () = unsafe {
let foo = Some(&42 as *const i32);

2
tests/ui/consts/issue-miri-1910.stderr
View File

@ -10,7 +10,7 @@ note: inside `std::ptr::read::<u8>`
note: inside `ptr::const_ptr::<impl *const u8>::read`
--> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
note: inside `C`
--> $DIR/issue-miri-1910.rs:8:5
--> $DIR/issue-miri-1910.rs:7:5
|
LL | (&foo as *const _ as *const u8).add(one_and_a_half_pointers).read();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^