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Rollup merge of #121179 - RalfJung:zst-mutable-refs, r=oli-obk

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allow mutable references in const values when they point to no memory

Fixes https://github.com/rust-lang/rust/issues/120450

The second commit is just some drive-by test suite cleanup.

r? `@oli-obk`
This commit is contained in:
Guillaume Gomez 2024-02-16 17:08:13 +01:00 • committed by GitHub
commit 0c92146034
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GPG key ID: B5690EEEBB952194
21 changed files with 209 additions and 387 deletions
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2
compiler/rustc_const_eval/messages.ftl
View file

@ -453,7 +453,7 @@ const_eval_validation_invalid_fn_ptr = {$front_matter}: encountered {$value}, bu
const_eval_validation_invalid_ref_meta = {$front_matter}: encountered invalid reference metadata: total size is bigger than largest supported object
const_eval_validation_invalid_ref_slice_meta = {$front_matter}: encountered invalid reference metadata: slice is bigger than largest supported object
const_eval_validation_invalid_vtable_ptr = {$front_matter}: encountered {$value}, but expected a vtable pointer
const_eval_validation_mutable_ref_in_const = {$front_matter}: encountered mutable reference in a `const` or `static`
const_eval_validation_mutable_ref_in_const_or_static = {$front_matter}: encountered mutable reference in a `const` or `static`
const_eval_validation_mutable_ref_to_immutable = {$front_matter}: encountered mutable reference or box pointing to read-only memory
const_eval_validation_never_val = {$front_matter}: encountered a value of the never type `!`
const_eval_validation_null_box = {$front_matter}: encountered a null box

24
compiler/rustc_const_eval/src/errors.rs
View file

@ -603,18 +603,18 @@ impl<'tcx> ReportErrorExt for ValidationErrorInfo<'tcx> {
PtrToUninhabited { ptr_kind: PointerKind::Box, .. } => {
const_eval_validation_box_to_uninhabited
}
PtrToUninhabited { ptr_kind: PointerKind::Ref, .. } => {
PtrToUninhabited { ptr_kind: PointerKind::Ref(_), .. } => {
const_eval_validation_ref_to_uninhabited
}
PtrToStatic { ptr_kind: PointerKind::Box } => const_eval_validation_box_to_static,
PtrToStatic { ptr_kind: PointerKind::Ref } => const_eval_validation_ref_to_static,
PtrToStatic { ptr_kind: PointerKind::Ref(_) } => const_eval_validation_ref_to_static,
PointerAsInt { .. } => const_eval_validation_pointer_as_int,
PartialPointer => const_eval_validation_partial_pointer,
ConstRefToMutable => const_eval_validation_const_ref_to_mutable,
ConstRefToExtern => const_eval_validation_const_ref_to_extern,
MutableRefInConst => const_eval_validation_mutable_ref_in_const,
MutableRefInConstOrStatic => const_eval_validation_mutable_ref_in_const_or_static,
MutableRefToImmutable => const_eval_validation_mutable_ref_to_immutable,
NullFnPtr => const_eval_validation_null_fn_ptr,
NeverVal => const_eval_validation_never_val,
@ -630,37 +630,39 @@ impl<'tcx> ReportErrorExt for ValidationErrorInfo<'tcx> {
InvalidMetaSliceTooLarge { ptr_kind: PointerKind::Box } => {
const_eval_validation_invalid_box_slice_meta
}
InvalidMetaSliceTooLarge { ptr_kind: PointerKind::Ref } => {
InvalidMetaSliceTooLarge { ptr_kind: PointerKind::Ref(_) } => {
const_eval_validation_invalid_ref_slice_meta
}
InvalidMetaTooLarge { ptr_kind: PointerKind::Box } => {
const_eval_validation_invalid_box_meta
}
InvalidMetaTooLarge { ptr_kind: PointerKind::Ref } => {
InvalidMetaTooLarge { ptr_kind: PointerKind::Ref(_) } => {
const_eval_validation_invalid_ref_meta
}
UnalignedPtr { ptr_kind: PointerKind::Ref, .. } => const_eval_validation_unaligned_ref,
UnalignedPtr { ptr_kind: PointerKind::Ref(_), .. } => {
const_eval_validation_unaligned_ref
}
UnalignedPtr { ptr_kind: PointerKind::Box, .. } => const_eval_validation_unaligned_box,
NullPtr { ptr_kind: PointerKind::Box } => const_eval_validation_null_box,
NullPtr { ptr_kind: PointerKind::Ref } => const_eval_validation_null_ref,
NullPtr { ptr_kind: PointerKind::Ref(_) } => const_eval_validation_null_ref,
DanglingPtrNoProvenance { ptr_kind: PointerKind::Box, .. } => {
const_eval_validation_dangling_box_no_provenance
}
DanglingPtrNoProvenance { ptr_kind: PointerKind::Ref, .. } => {
DanglingPtrNoProvenance { ptr_kind: PointerKind::Ref(_), .. } => {
const_eval_validation_dangling_ref_no_provenance
}
DanglingPtrOutOfBounds { ptr_kind: PointerKind::Box } => {
const_eval_validation_dangling_box_out_of_bounds
}
DanglingPtrOutOfBounds { ptr_kind: PointerKind::Ref } => {
DanglingPtrOutOfBounds { ptr_kind: PointerKind::Ref(_) } => {
const_eval_validation_dangling_ref_out_of_bounds
}
DanglingPtrUseAfterFree { ptr_kind: PointerKind::Box } => {
const_eval_validation_dangling_box_use_after_free
}
DanglingPtrUseAfterFree { ptr_kind: PointerKind::Ref } => {
DanglingPtrUseAfterFree { ptr_kind: PointerKind::Ref(_) } => {
const_eval_validation_dangling_ref_use_after_free
}
InvalidBool { .. } => const_eval_validation_invalid_bool,
@ -766,7 +768,7 @@ impl<'tcx> ReportErrorExt for ValidationErrorInfo<'tcx> {
}
NullPtr { .. }
| PtrToStatic { .. }
| MutableRefInConst
| MutableRefInConstOrStatic
| ConstRefToMutable
| ConstRefToExtern
| MutableRefToImmutable

85
compiler/rustc_const_eval/src/interpret/validity.rs
View file

@ -445,22 +445,22 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
// Determine whether this pointer expects to be pointing to something mutable.
let ptr_expected_mutbl = match ptr_kind {
PointerKind::Box => Mutability::Mut,
PointerKind::Ref => {
let tam = value.layout.ty.builtin_deref(false).unwrap();
// ZST never require mutability. We do not take into account interior mutability
// here since we cannot know if there really is an `UnsafeCell` inside
// `Option<UnsafeCell>` -- so we check that in the recursive descent behind this
// reference.
if size == Size::ZERO { Mutability::Not } else { tam.mutbl }
PointerKind::Ref(mutbl) => {
// We do not take into account interior mutability here since we cannot know if
// there really is an `UnsafeCell` inside `Option<UnsafeCell>` -- so we check
// that in the recursive descent behind this reference (controlled by
// `allow_immutable_unsafe_cell`).
mutbl
}
};
// Proceed recursively even for ZST, no reason to skip them!
// `!` is a ZST and we want to validate it.
if let Ok((alloc_id, _offset, _prov)) = self.ecx.ptr_try_get_alloc_id(place.ptr()) {
let mut skip_recursive_check = false;
// Let's see what kind of memory this points to.
// `unwrap` since dangling pointers have already been handled.
let alloc_kind = self.ecx.tcx.try_get_global_alloc(alloc_id).unwrap();
match alloc_kind {
let alloc_actual_mutbl = match alloc_kind {
GlobalAlloc::Static(did) => {
// Special handling for pointers to statics (irrespective of their type).
assert!(!self.ecx.tcx.is_thread_local_static(did));
@ -474,12 +474,6 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
.no_bound_vars()
.expect("statics should not have generic parameters")
.is_freeze(*self.ecx.tcx, ty::ParamEnv::reveal_all());
// Mutability check.
if ptr_expected_mutbl == Mutability::Mut {
if !is_mut {
throw_validation_failure!(self.path, MutableRefToImmutable);
}
}
// Mode-specific checks
match self.ctfe_mode {
Some(
@ -494,15 +488,9 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
// trigger cycle errors if we try to compute the value of the other static
// and that static refers back to us (potentially through a promoted).
// This could miss some UB, but that's fine.
return Ok(());
skip_recursive_check = true;
}
Some(CtfeValidationMode::Const { .. }) => {
// For consts on the other hand we have to recursively check;
// pattern matching assumes a valid value. However we better make
// sure this is not mutable.
if is_mut {
throw_validation_failure!(self.path, ConstRefToMutable);
}
// We can't recursively validate `extern static`, so we better reject them.
if self.ecx.tcx.is_foreign_item(did) {
throw_validation_failure!(self.path, ConstRefToExtern);
@ -510,25 +498,38 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
}
None => {}
}
// Return alloc mutability
if is_mut { Mutability::Mut } else { Mutability::Not }
}
GlobalAlloc::Memory(alloc) => {
if alloc.inner().mutability == Mutability::Mut
&& matches!(self.ctfe_mode, Some(CtfeValidationMode::Const { .. }))
{
throw_validation_failure!(self.path, ConstRefToMutable);
}
if ptr_expected_mutbl == Mutability::Mut
&& alloc.inner().mutability == Mutability::Not
{
throw_validation_failure!(self.path, MutableRefToImmutable);
}
}
GlobalAlloc::Memory(alloc) => alloc.inner().mutability,
GlobalAlloc::Function(..) | GlobalAlloc::VTable(..) => {
// These are immutable, we better don't allow mutable pointers here.
if ptr_expected_mutbl == Mutability::Mut {
throw_validation_failure!(self.path, MutableRefToImmutable);
}
Mutability::Not
}
};
// Mutability check.
// If this allocation has size zero, there is no actual mutability here.
let (size, _align, _alloc_kind) = self.ecx.get_alloc_info(alloc_id);
if size != Size::ZERO {
if ptr_expected_mutbl == Mutability::Mut
&& alloc_actual_mutbl == Mutability::Not
{
throw_validation_failure!(self.path, MutableRefToImmutable);
}
if ptr_expected_mutbl == Mutability::Mut
&& self.ctfe_mode.is_some_and(|c| !c.may_contain_mutable_ref())
{
throw_validation_failure!(self.path, MutableRefInConstOrStatic);
}
if alloc_actual_mutbl == Mutability::Mut
&& matches!(self.ctfe_mode, Some(CtfeValidationMode::Const { .. }))
{
throw_validation_failure!(self.path, ConstRefToMutable);
}
}
// Potentially skip recursive check.
if skip_recursive_check {
return Ok(());
}
}
let path = &self.path;
@ -598,16 +599,8 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
}
Ok(true)
}
ty::Ref(_, ty, mutbl) => {
if self.ctfe_mode.is_some_and(|c| !c.may_contain_mutable_ref())
&& *mutbl == Mutability::Mut
{
let layout = self.ecx.layout_of(*ty)?;
if !layout.is_zst() {
throw_validation_failure!(self.path, MutableRefInConst);
}
}
self.check_safe_pointer(value, PointerKind::Ref)?;
ty::Ref(_, _ty, mutbl) => {
self.check_safe_pointer(value, PointerKind::Ref(*mutbl))?;
Ok(true)
}
ty::FnPtr(_sig) => {

9
compiler/rustc_middle/src/mir/interpret/error.rs
View file

@ -12,6 +12,7 @@ use rustc_macros::HashStable;
use rustc_session::CtfeBacktrace;
use rustc_span::{def_id::DefId, Span, DUMMY_SP};
use rustc_target::abi::{call, Align, Size, VariantIdx, WrappingRange};
use rustc_type_ir::Mutability;
use std::borrow::Cow;
use std::{any::Any, backtrace::Backtrace, fmt};
@ -367,7 +368,7 @@ pub enum UndefinedBehaviorInfo<'tcx> {
#[derive(Debug, Clone, Copy)]
pub enum PointerKind {
Ref,
Ref(Mutability),
Box,
}
@ -375,7 +376,7 @@ impl IntoDiagnosticArg for PointerKind {
fn into_diagnostic_arg(self) -> DiagnosticArgValue {
DiagnosticArgValue::Str(
match self {
Self::Ref => "ref",
Self::Ref(_) => "ref",
Self::Box => "box",
}
.into(),
@ -408,7 +409,7 @@ impl From<PointerKind> for ExpectedKind {
fn from(x: PointerKind) -> ExpectedKind {
match x {
PointerKind::Box => ExpectedKind::Box,
PointerKind::Ref => ExpectedKind::Reference,
PointerKind::Ref(_) => ExpectedKind::Reference,
}
}
}
@ -419,7 +420,7 @@ pub enum ValidationErrorKind<'tcx> {
PartialPointer,
PtrToUninhabited { ptr_kind: PointerKind, ty: Ty<'tcx> },
PtrToStatic { ptr_kind: PointerKind },
MutableRefInConst,
MutableRefInConstOrStatic,
ConstRefToMutable,
ConstRefToExtern,
MutableRefToImmutable,

52
tests/ui/consts/const-eval/validate_uninhabited_zsts.64bit.stderr
View file

@ -1,52 +0,0 @@
warning: the type `!` does not permit zero-initialization
--> $DIR/validate_uninhabited_zsts.rs:4:14
|
LL | unsafe { std::mem::transmute(()) }
| ^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed
|
= note: the `!` type has no valid value
= note: `#[warn(invalid_value)]` on by default
error[E0080]: evaluation of constant value failed
--> $DIR/validate_uninhabited_zsts.rs:4:14
|
LL | unsafe { std::mem::transmute(()) }
| ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a value of the never type `!`
|
note: inside `foo`
--> $DIR/validate_uninhabited_zsts.rs:4:14
|
LL | unsafe { std::mem::transmute(()) }
| ^^^^^^^^^^^^^^^^^^^^^^^
note: inside `FOO`
--> $DIR/validate_uninhabited_zsts.rs:19:33
|
LL | const FOO: [empty::Empty; 3] = [foo(); 3];
| ^^^^^
error[E0080]: evaluation of constant value failed
--> $DIR/validate_uninhabited_zsts.rs:21:42
|
LL | const BAR: [empty::Empty; 3] = [unsafe { std::mem::transmute(()) }; 3];
| ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .0: encountered a value of uninhabited type `Void`
warning: the type `empty::Empty` does not permit zero-initialization
--> $DIR/validate_uninhabited_zsts.rs:21:42
|
LL | const BAR: [empty::Empty; 3] = [unsafe { std::mem::transmute(()) }; 3];
| ^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed
|
note: in this struct field
--> $DIR/validate_uninhabited_zsts.rs:16:22
|
LL | pub struct Empty(Void);
| ^^^^
note: enums with no inhabited variants have no valid value
--> $DIR/validate_uninhabited_zsts.rs:13:5
|
LL | enum Void {}
| ^^^^^^^^^
error: aborting due to 2 previous errors; 2 warnings emitted
For more information about this error, try `rustc --explain E0080`.

2
tests/ui/consts/const-eval/validate_uninhabited_zsts.rs
View file

@ -1,5 +1,3 @@
// stderr-per-bitwidth
const fn foo() -> ! {
unsafe { std::mem::transmute(()) }
//~^ ERROR evaluation of constant value failed

16
tests/ui/consts/const-eval/validate_uninhabited_zsts.32bit.stderr → tests/ui/consts/const-eval/validate_uninhabited_zsts.stderr
View file

@ -1,5 +1,5 @@
warning: the type `!` does not permit zero-initialization
--> $DIR/validate_uninhabited_zsts.rs:4:14
--> $DIR/validate_uninhabited_zsts.rs:2:14
|
LL | unsafe { std::mem::transmute(()) }
| ^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed
@ -8,41 +8,41 @@ LL | unsafe { std::mem::transmute(()) }
= note: `#[warn(invalid_value)]` on by default
error[E0080]: evaluation of constant value failed
--> $DIR/validate_uninhabited_zsts.rs:4:14
--> $DIR/validate_uninhabited_zsts.rs:2:14
|
LL | unsafe { std::mem::transmute(()) }
| ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a value of the never type `!`
|
note: inside `foo`
--> $DIR/validate_uninhabited_zsts.rs:4:14
--> $DIR/validate_uninhabited_zsts.rs:2:14
|
LL | unsafe { std::mem::transmute(()) }
| ^^^^^^^^^^^^^^^^^^^^^^^
note: inside `FOO`
--> $DIR/validate_uninhabited_zsts.rs:19:33
--> $DIR/validate_uninhabited_zsts.rs:17:33
|
LL | const FOO: [empty::Empty; 3] = [foo(); 3];
| ^^^^^
error[E0080]: evaluation of constant value failed
--> $DIR/validate_uninhabited_zsts.rs:21:42
--> $DIR/validate_uninhabited_zsts.rs:19:42
|
LL | const BAR: [empty::Empty; 3] = [unsafe { std::mem::transmute(()) }; 3];
| ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .0: encountered a value of uninhabited type `Void`
warning: the type `empty::Empty` does not permit zero-initialization
--> $DIR/validate_uninhabited_zsts.rs:21:42
--> $DIR/validate_uninhabited_zsts.rs:19:42
|
LL | const BAR: [empty::Empty; 3] = [unsafe { std::mem::transmute(()) }; 3];
| ^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed
|
note: in this struct field
--> $DIR/validate_uninhabited_zsts.rs:16:22
--> $DIR/validate_uninhabited_zsts.rs:14:22
|
LL | pub struct Empty(Void);
| ^^^^
note: enums with no inhabited variants have no valid value
--> $DIR/validate_uninhabited_zsts.rs:13:5
--> $DIR/validate_uninhabited_zsts.rs:11:5
|
LL | enum Void {}
| ^^^^^^^^^

6
tests/ui/consts/const-mut-refs/const_mut_refs.rs
View file

@ -1,6 +1,8 @@
// check-pass
#![feature(const_mut_refs)]
use std::sync::Mutex;
struct Foo {
x: usize
}
@ -28,6 +30,10 @@ const fn bazz(foo: &mut Foo) -> usize {
foo.x
}
// Empty slices get promoted so this passes the static checks.
// Make sure it also passes the dynamic checks.
static MUTABLE_REFERENCE_HOLDER: Mutex<&mut [u8]> = Mutex::new(&mut []);
fn main() {
let _: [(); foo().bar()] = [(); 1];
let _: [(); baz(&mut foo())] = [(); 2];

26
tests/ui/consts/const-mut-refs/issue-76510.64bit.stderr
View file

@ -1,26 +0,0 @@
error[E0764]: mutable references are not allowed in the final value of constants
--> $DIR/issue-76510.rs:5:29
|
LL | const S: &'static mut str = &mut " hello ";
| ^^^^^^^^^^^^^^
error[E0658]: mutation through a reference is not allowed in constants
--> $DIR/issue-76510.rs:5:29
|
LL | const S: &'static mut str = &mut " hello ";
| ^^^^^^^^^^^^^^
|
= note: see issue #57349 <https://github.com/rust-lang/rust/issues/57349> for more information
= help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
= note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
error[E0596]: cannot borrow data in a `&` reference as mutable
--> $DIR/issue-76510.rs:5:29
|
LL | const S: &'static mut str = &mut " hello ";
| ^^^^^^^^^^^^^^ cannot borrow as mutable
error: aborting due to 3 previous errors
Some errors have detailed explanations: E0596, E0658, E0764.
For more information about an error, try `rustc --explain E0596`.

2
tests/ui/consts/const-mut-refs/issue-76510.rs
View file

@ -1,5 +1,3 @@
// stderr-per-bitwidth
use std::mem::{transmute, ManuallyDrop};
const S: &'static mut str = &mut " hello ";

6
tests/ui/consts/const-mut-refs/issue-76510.32bit.stderr → tests/ui/consts/const-mut-refs/issue-76510.stderr
View file

@ -1,11 +1,11 @@
error[E0764]: mutable references are not allowed in the final value of constants
--> $DIR/issue-76510.rs:5:29
--> $DIR/issue-76510.rs:3:29
|
LL | const S: &'static mut str = &mut " hello ";
| ^^^^^^^^^^^^^^
error[E0658]: mutation through a reference is not allowed in constants
--> $DIR/issue-76510.rs:5:29
--> $DIR/issue-76510.rs:3:29
|
LL | const S: &'static mut str = &mut " hello ";
| ^^^^^^^^^^^^^^
@ -15,7 +15,7 @@ LL | const S: &'static mut str = &mut " hello ";
= note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
error[E0596]: cannot borrow data in a `&` reference as mutable
--> $DIR/issue-76510.rs:5:29
--> $DIR/issue-76510.rs:3:29
|
LL | const S: &'static mut str = &mut " hello ";
| ^^^^^^^^^^^^^^ cannot borrow as mutable

20
tests/ui/consts/const-mut-refs/mut_ref_in_final_dynamic_check.32bit.stderr
View file

@ -1,20 +0,0 @@
error[E0080]: it is undefined behavior to use this value
--> $DIR/mut_ref_in_final_dynamic_check.rs:15:1
|
LL | const A: Option<&mut i32> = helper();
| ^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-variant(Some)>.0: encountered mutable reference in a `const` or `static`
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: 4, align: 4) {
2a 00 00 00 │ *...
}
error: encountered dangling pointer in final value of constant
--> $DIR/mut_ref_in_final_dynamic_check.rs:22:1
|
LL | const B: Option<&mut i32> = helper2();
| ^^^^^^^^^^^^^^^^^^^^^^^^^
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0080`.

20
tests/ui/consts/const-mut-refs/mut_ref_in_final_dynamic_check.64bit.stderr
View file

@ -1,20 +0,0 @@
error[E0080]: it is undefined behavior to use this value
--> $DIR/mut_ref_in_final_dynamic_check.rs:15:1
|
LL | const A: Option<&mut i32> = helper();
| ^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-variant(Some)>.0: encountered mutable reference in a `const` or `static`
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: 8, align: 8) {
2a 00 00 00 00 00 00 00 │ *.......
}
error: encountered dangling pointer in final value of constant
--> $DIR/mut_ref_in_final_dynamic_check.rs:22:1
|
LL | const B: Option<&mut i32> = helper2();
| ^^^^^^^^^^^^^^^^^^^^^^^^^
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0080`.

36
tests/ui/consts/const-mut-refs/mut_ref_in_final_dynamic_check.rs
View file

@ -1,24 +1,48 @@
// stderr-per-bitwidth
#![feature(const_mut_refs)]
// normalize-stderr-test "(the raw bytes of the constant) \(size: [0-9]*, align: [0-9]*\)" -> "$1 (size: $$SIZE, align: $$ALIGN)"
// normalize-stderr-test "( 0x[0-9a-f][0-9a-f] │)? ([0-9a-f][0-9a-f] |__ |╾─*ALLOC[0-9]+(\+[a-z0-9]+)?(<imm>)?─*╼ )+ *│.*" -> " HEX_DUMP"
// normalize-stderr-test "HEX_DUMP\s*\n\s*HEX_DUMP" -> "HEX_DUMP"
#![feature(const_mut_refs, const_refs_to_static)]
#![feature(raw_ref_op)]
use std::sync::Mutex;
// This file checks that our dynamic checks catch things that the static checks miss.
// We do not have static checks for these, because we do not look into function bodies.
// We treat all functions as not returning a mutable reference, because there is no way to
// do that without causing the borrow checker to complain (see the B4/helper test in
// mut_ref_in_final.rs).
static mut BUFFER: i32 = 42;
const fn helper() -> Option<&'static mut i32> { unsafe {
Some(&mut *std::ptr::addr_of_mut!(BUFFER))
} }
const MUT: Option<&mut i32> = helper(); //~ ERROR it is undefined behavior to use this value
//~^ encountered mutable reference
static MUT_STATIC: Option<&mut i32> = helper(); //~ ERROR it is undefined behavior to use this value
//~^ encountered mutable reference
const fn helper_int2ptr() -> Option<&'static mut i32> { unsafe {
// Undefined behaviour (integer as pointer), who doesn't love tests like this.
Some(&mut *(42 as *mut i32))
} }
const A: Option<&mut i32> = helper(); //~ ERROR it is undefined behavior to use this value
//~^ encountered mutable reference in a `const`
const INT2PTR: Option<&mut i32> = helper_int2ptr(); //~ ERROR it is undefined behavior to use this value
//~^ encountered a dangling reference
static INT2PTR_STATIC: Option<&mut i32> = helper_int2ptr(); //~ ERROR it is undefined behavior to use this value
//~^ encountered a dangling reference
const fn helper2() -> Option<&'static mut i32> { unsafe {
const fn helper_dangling() -> Option<&'static mut i32> { unsafe {
// Undefined behaviour (dangling pointer), who doesn't love tests like this.
Some(&mut *(&mut 42 as *mut i32))
} }
const B: Option<&mut i32> = helper2(); //~ ERROR encountered dangling pointer in final value of constant
const DANGLING: Option<&mut i32> = helper_dangling(); //~ ERROR encountered dangling pointer
static DANGLING_STATIC: Option<&mut i32> = helper_dangling(); //~ ERROR encountered dangling pointer
// Variant of the real-world case in <https://github.com/rust-lang/rust/issues/120450>.
// Maybe we should allow this in the future (then the rest should move to `const_mut_refs.rs`),
// but for now we reject it.
static mut MUT_ARRAY: &mut [u8] = &mut [42];
static MUTEX: Mutex<&mut [u8]> = Mutex::new(unsafe { &mut *MUT_ARRAY }); //~ ERROR it is undefined behavior to use this value
//~^ encountered mutable reference
fn main() {}

70
tests/ui/consts/const-mut-refs/mut_ref_in_final_dynamic_check.stderr Normal file
View file

@ -0,0 +1,70 @@
error[E0080]: it is undefined behavior to use this value
--> $DIR/mut_ref_in_final_dynamic_check.rs:20:1
|
LL | const MUT: Option<&mut i32> = helper();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-variant(Some)>.0: encountered mutable reference in a `const` or `static`
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: $SIZE, align: $ALIGN) {
HEX_DUMP
}
error[E0080]: it is undefined behavior to use this value
--> $DIR/mut_ref_in_final_dynamic_check.rs:22:1
|
LL | static MUT_STATIC: Option<&mut i32> = helper();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-variant(Some)>.0: encountered mutable reference in a `const` or `static`
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: $SIZE, align: $ALIGN) {
HEX_DUMP
}
error[E0080]: it is undefined behavior to use this value
--> $DIR/mut_ref_in_final_dynamic_check.rs:29:1
|
LL | const INT2PTR: Option<&mut i32> = helper_int2ptr();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-variant(Some)>.0: encountered a dangling reference (0x2a[noalloc] has no provenance)
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: $SIZE, align: $ALIGN) {
HEX_DUMP
}
error[E0080]: it is undefined behavior to use this value
--> $DIR/mut_ref_in_final_dynamic_check.rs:31:1
|
LL | static INT2PTR_STATIC: Option<&mut i32> = helper_int2ptr();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .<enum-variant(Some)>.0: encountered a dangling reference (0x2a[noalloc] has no provenance)
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: $SIZE, align: $ALIGN) {
HEX_DUMP
}
error: encountered dangling pointer in final value of constant
--> $DIR/mut_ref_in_final_dynamic_check.rs:38:1
|
LL | const DANGLING: Option<&mut i32> = helper_dangling();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: encountered dangling pointer in final value of static
--> $DIR/mut_ref_in_final_dynamic_check.rs:39:1
|
LL | static DANGLING_STATIC: Option<&mut i32> = helper_dangling();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0080]: it is undefined behavior to use this value
--> $DIR/mut_ref_in_final_dynamic_check.rs:45:1
|
LL | static MUTEX: Mutex<&mut [u8]> = Mutex::new(unsafe { &mut *MUT_ARRAY });
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .data.value: encountered mutable reference in a `const` or `static`
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: $SIZE, align: $ALIGN) {
HEX_DUMP
}
error: aborting due to 7 previous errors
For more information about this error, try `rustc --explain E0080`.

65
tests/ui/consts/miri_unleashed/const_refers_to_static.64bit.stderr
View file

@ -1,65 +0,0 @@
error[E0080]: evaluation of constant value failed
--> $DIR/const_refers_to_static.rs:9:5
|
LL | FOO.fetch_add(1, Ordering::Relaxed)
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ calling non-const function `AtomicUsize::fetch_add`
error[E0080]: evaluation of constant value failed
--> $DIR/const_refers_to_static.rs:14:14
|
LL | unsafe { *(&FOO as *const _ as *const usize) }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constant accesses mutable global memory
error[E0080]: evaluation of constant value failed
--> $DIR/const_refers_to_static.rs:18:32
|
LL | const READ_MUT: u32 = unsafe { MUTABLE };
| ^^^^^^^ constant accesses mutable global memory
error[E0080]: it is undefined behavior to use this value
--> $DIR/const_refers_to_static.rs:21:1
|
LL | const REF_INTERIOR_MUT: &usize = {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered reference to mutable memory in `const`
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: 8, align: 8) {
╾ALLOC0<imm>╼ │ ╾──────╼
}
warning: skipping const checks
|
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static.rs:9:5
|
LL | FOO.fetch_add(1, Ordering::Relaxed)
| ^^^
help: skipping check that does not even have a feature gate
--> $DIR/const_refers_to_static.rs:9:5
|
LL | FOO.fetch_add(1, Ordering::Relaxed)
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static.rs:14:17
|
LL | unsafe { *(&FOO as *const _ as *const usize) }
| ^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static.rs:18:32
|
LL | const READ_MUT: u32 = unsafe { MUTABLE };
| ^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static.rs:24:18
|
LL | unsafe { &*(&FOO as *const _ as *const usize) }
| ^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static.rs:29:25
|
LL | const REF_IMMUT: &u8 = &MY_STATIC;
| ^^^^^^^^^
error: aborting due to 4 previous errors; 1 warning emitted
For more information about this error, try `rustc --explain E0080`.

3
tests/ui/consts/miri_unleashed/const_refers_to_static.rs
View file

@ -1,5 +1,6 @@
// compile-flags: -Zunleash-the-miri-inside-of-you
// stderr-per-bitwidth
// 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] |╾─*ALLOC[0-9]+(\+[a-z0-9]+)?(<imm>)?─*╼ )+ *│.*" -> "HEX_DUMP"
use std::sync::atomic::AtomicUsize;
use std::sync::atomic::Ordering;

24
tests/ui/consts/miri_unleashed/const_refers_to_static.32bit.stderr → tests/ui/consts/miri_unleashed/const_refers_to_static.stderr
View file

@ -1,61 +1,61 @@
error[E0080]: evaluation of constant value failed
--> $DIR/const_refers_to_static.rs:9:5
--> $DIR/const_refers_to_static.rs:10:5
|
LL | FOO.fetch_add(1, Ordering::Relaxed)
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ calling non-const function `AtomicUsize::fetch_add`
error[E0080]: evaluation of constant value failed
--> $DIR/const_refers_to_static.rs:14:14
--> $DIR/const_refers_to_static.rs:15:14
|
LL | unsafe { *(&FOO as *const _ as *const usize) }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constant accesses mutable global memory
error[E0080]: evaluation of constant value failed
--> $DIR/const_refers_to_static.rs:18:32
--> $DIR/const_refers_to_static.rs:19:32
|
LL | const READ_MUT: u32 = unsafe { MUTABLE };
| ^^^^^^^ constant accesses mutable global memory
error[E0080]: it is undefined behavior to use this value
--> $DIR/const_refers_to_static.rs:21:1
--> $DIR/const_refers_to_static.rs:22:1
|
LL | const REF_INTERIOR_MUT: &usize = {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered reference to mutable memory in `const`
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: 4, align: 4) {
╾ALLOC0<imm>╼ │ ╾──╼
= note: the raw bytes of the constant (size: $SIZE, align: $ALIGN) {
HEX_DUMP
}
warning: skipping const checks
|
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static.rs:9:5
--> $DIR/const_refers_to_static.rs:10:5
|
LL | FOO.fetch_add(1, Ordering::Relaxed)
| ^^^
help: skipping check that does not even have a feature gate
--> $DIR/const_refers_to_static.rs:9:5
--> $DIR/const_refers_to_static.rs:10:5
|
LL | FOO.fetch_add(1, Ordering::Relaxed)
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static.rs:14:17
--> $DIR/const_refers_to_static.rs:15:17
|
LL | unsafe { *(&FOO as *const _ as *const usize) }
| ^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static.rs:18:32
--> $DIR/const_refers_to_static.rs:19:32
|
LL | const READ_MUT: u32 = unsafe { MUTABLE };
| ^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static.rs:24:18
--> $DIR/const_refers_to_static.rs:25:18
|
LL | unsafe { &*(&FOO as *const _ as *const usize) }
| ^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static.rs:29:25
--> $DIR/const_refers_to_static.rs:30:25
|
LL | const REF_IMMUT: &u8 = &MY_STATIC;
| ^^^^^^^^^

89
tests/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.64bit.stderr
View file

@ -1,89 +0,0 @@
error[E0080]: it is undefined behavior to use this value
--> $DIR/const_refers_to_static_cross_crate.rs:11:1
|
LL | const SLICE_MUT: &[u8; 1] = {
| ^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered reference to mutable memory in `const`
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: 8, align: 8) {
╾ALLOC0<imm>╼ │ ╾──────╼
}
error: could not evaluate constant pattern
--> $DIR/const_refers_to_static_cross_crate.rs:39:9
|
LL | SLICE_MUT => true,
| ^^^^^^^^^
error[E0080]: it is undefined behavior to use this value
--> $DIR/const_refers_to_static_cross_crate.rs:16:1
|
LL | const U8_MUT: &u8 = {
| ^^^^^^^^^^^^^^^^^ constructing invalid value: encountered reference to mutable memory in `const`
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: 8, align: 8) {
╾ALLOC0<imm>╼ │ ╾──────╼
}
error: could not evaluate constant pattern
--> $DIR/const_refers_to_static_cross_crate.rs:47:9
|
LL | U8_MUT => true,
| ^^^^^^
error[E0080]: it is undefined behavior to use this value
--> $DIR/const_refers_to_static_cross_crate.rs:22:1
|
LL | const U8_MUT2: &u8 = {
| ^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered reference to mutable memory in `const`
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: 8, align: 8) {
╾ALLOC0<imm>╼ │ ╾──────╼
}
error: could not evaluate constant pattern
--> $DIR/const_refers_to_static_cross_crate.rs:57:9
|
LL | U8_MUT2 => true,
| ^^^^^^^
error[E0080]: evaluation of constant value failed
--> $DIR/const_refers_to_static_cross_crate.rs:28:15
|
LL | match static_cross_crate::OPT_ZERO {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constant accesses mutable global memory
error: could not evaluate constant pattern
--> $DIR/const_refers_to_static_cross_crate.rs:64:9
|
LL | U8_MUT3 => true,
| ^^^^^^^
warning: skipping const checks
|
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:13:15
|
LL | unsafe { &static_cross_crate::ZERO }
| ^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:18:15
|
LL | unsafe { &static_cross_crate::ZERO[0] }
| ^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:24:17
|
LL | unsafe { &(*static_cross_crate::ZERO_REF)[0] }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:28:15
|
LL | match static_cross_crate::OPT_ZERO {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: aborting due to 8 previous errors; 1 warning emitted
For more information about this error, try `rustc --explain E0080`.

3
tests/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.rs
View file

@ -1,6 +1,7 @@
// compile-flags: -Zunleash-the-miri-inside-of-you
// aux-build:static_cross_crate.rs
// stderr-per-bitwidth
// 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] |╾─*ALLOC[0-9]+(\+[a-z0-9]+)?(<imm>)?─*╼ )+ *│.*" -> "HEX_DUMP"
#![feature(exclusive_range_pattern, half_open_range_patterns_in_slices)]
#![allow(static_mut_ref)]

36
tests/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.32bit.stderr → tests/ui/consts/miri_unleashed/const_refers_to_static_cross_crate.stderr
View file

@ -1,62 +1,62 @@
error[E0080]: it is undefined behavior to use this value
--> $DIR/const_refers_to_static_cross_crate.rs:11:1
--> $DIR/const_refers_to_static_cross_crate.rs:12:1
|
LL | const SLICE_MUT: &[u8; 1] = {
| ^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered reference to mutable memory in `const`
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: 4, align: 4) {
╾ALLOC0<imm>╼ │ ╾──╼
= note: the raw bytes of the constant (size: $SIZE, align: $ALIGN) {
HEX_DUMP
}
error: could not evaluate constant pattern
--> $DIR/const_refers_to_static_cross_crate.rs:39:9
--> $DIR/const_refers_to_static_cross_crate.rs:40:9
|
LL | SLICE_MUT => true,
| ^^^^^^^^^
error[E0080]: it is undefined behavior to use this value
--> $DIR/const_refers_to_static_cross_crate.rs:16:1
--> $DIR/const_refers_to_static_cross_crate.rs:17:1
|
LL | const U8_MUT: &u8 = {
| ^^^^^^^^^^^^^^^^^ constructing invalid value: encountered reference to mutable memory in `const`
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: 4, align: 4) {
╾ALLOC0<imm>╼ │ ╾──╼
= note: the raw bytes of the constant (size: $SIZE, align: $ALIGN) {
HEX_DUMP
}
error: could not evaluate constant pattern
--> $DIR/const_refers_to_static_cross_crate.rs:47:9
--> $DIR/const_refers_to_static_cross_crate.rs:48:9
|
LL | U8_MUT => true,
| ^^^^^^
error[E0080]: it is undefined behavior to use this value
--> $DIR/const_refers_to_static_cross_crate.rs:22:1
--> $DIR/const_refers_to_static_cross_crate.rs:23:1
|
LL | const U8_MUT2: &u8 = {
| ^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered reference to mutable memory in `const`
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
= note: the raw bytes of the constant (size: 4, align: 4) {
╾ALLOC0<imm>╼ │ ╾──╼
= note: the raw bytes of the constant (size: $SIZE, align: $ALIGN) {
HEX_DUMP
}
error: could not evaluate constant pattern
--> $DIR/const_refers_to_static_cross_crate.rs:57:9
--> $DIR/const_refers_to_static_cross_crate.rs:58:9
|
LL | U8_MUT2 => true,
| ^^^^^^^
error[E0080]: evaluation of constant value failed
--> $DIR/const_refers_to_static_cross_crate.rs:28:15
--> $DIR/const_refers_to_static_cross_crate.rs:29:15
|
LL | match static_cross_crate::OPT_ZERO {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constant accesses mutable global memory
error: could not evaluate constant pattern
--> $DIR/const_refers_to_static_cross_crate.rs:64:9
--> $DIR/const_refers_to_static_cross_crate.rs:65:9
|
LL | U8_MUT3 => true,
| ^^^^^^^
@ -64,22 +64,22 @@ LL | U8_MUT3 => true,
warning: skipping const checks
|
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:13:15
--> $DIR/const_refers_to_static_cross_crate.rs:14:15
|
LL | unsafe { &static_cross_crate::ZERO }
| ^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:18:15
--> $DIR/const_refers_to_static_cross_crate.rs:19:15
|
LL | unsafe { &static_cross_crate::ZERO[0] }
| ^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:24:17
--> $DIR/const_refers_to_static_cross_crate.rs:25:17
|
LL | unsafe { &(*static_cross_crate::ZERO_REF)[0] }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: skipping check for `const_refs_to_static` feature
--> $DIR/const_refers_to_static_cross_crate.rs:28:15
--> $DIR/const_refers_to_static_cross_crate.rs:29:15
|
LL | match static_cross_crate::OPT_ZERO {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^