bjoernager/rust
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detect consts that reference extern statics

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This commit is contained in:
Ralf Jung 2024-01-06 15:06:22 +01:00
parent 9c0623fe8f
commit 77f8c3caea
9 changed files with 97 additions and 51 deletions
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7
compiler/rustc_const_eval/src/const_eval/eval_queries.rs
View file

@ -360,7 +360,7 @@ pub fn const_validate_mplace<'mir, 'tcx>(
// Promoteds in statics are consts that re allowed to point to statics.
CtfeValidationMode::Const {
allow_immutable_unsafe_cell: false,
allow_static_ptrs: true,
allow_extern_static_ptrs: true,
}
}
Some(mutbl) => CtfeValidationMode::Static { mutbl }, // a `static`
@ -368,7 +368,10 @@ pub fn const_validate_mplace<'mir, 'tcx>(
// In normal `const` (not promoted), the outermost allocation is always only copied,
// so having `UnsafeCell` in there is okay despite them being in immutable memory.
let allow_immutable_unsafe_cell = cid.promoted.is_none() && !inner;
CtfeValidationMode::Const { allow_immutable_unsafe_cell, allow_static_ptrs: false }
CtfeValidationMode::Const {
allow_immutable_unsafe_cell,
allow_extern_static_ptrs: false,
}
}
};
ecx.const_validate_operand(&mplace.into(), path, &mut ref_tracking, mode)?;

2
compiler/rustc_const_eval/src/errors.rs
View file

@ -612,6 +612,7 @@ impl<'tcx> ReportErrorExt for ValidationErrorInfo<'tcx> {
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,
MutableRefToImmutable => const_eval_validation_mutable_ref_to_immutable,
NullFnPtr => const_eval_validation_null_fn_ptr,
@ -767,6 +768,7 @@ impl<'tcx> ReportErrorExt for ValidationErrorInfo<'tcx> {
| PtrToStatic { .. }
| MutableRefInConst
| ConstRefToMutable
| ConstRefToExtern
| MutableRefToImmutable
| NullFnPtr
| NeverVal

14
compiler/rustc_const_eval/src/interpret/validity.rs
View file

@ -133,7 +133,7 @@ pub enum CtfeValidationMode {
/// `allow_immutable_unsafe_cell` says whether we allow `UnsafeCell` in immutable memory (which is the
/// case for the top-level allocation of a `const`, where this is fine because the allocation will be
/// copied at each use site).
Const { allow_immutable_unsafe_cell: bool, allow_static_ptrs: bool },
Const { allow_immutable_unsafe_cell: bool, allow_extern_static_ptrs: bool },
}
impl CtfeValidationMode {
@ -488,13 +488,23 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
// This could miss some UB, but that's fine.
return Ok(());
}
Some(CtfeValidationMode::Const { .. }) => {
Some(CtfeValidationMode::Const {
allow_extern_static_ptrs, ..
}) => {
// 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);
}
if self.ecx.tcx.is_foreign_item(did) {
if !allow_extern_static_ptrs {
throw_validation_failure!(self.path, ConstRefToExtern);
} else {
// We can't validate this...
return Ok(());
}
}
}
None => {}
}