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add new rustc_const_stable_intrinsic attribute for const-stable intrinsics

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This commit is contained in:
Ralf Jung 2024-11-01 22:53:59 +01:00
parent 10723c2896
commit 1f0ed2b0f5
9 changed files with 80 additions and 68 deletions
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13
compiler/rustc_const_eval/src/check_consts/check.rs
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@ -736,16 +736,19 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
// Intrinsics are language primitives, not regular calls, so treat them separately.
if let Some(intrinsic) = tcx.intrinsic(callee) {
// We use `intrinsic.const_stable` to determine if this can be safely exposed to
// stable code, rather than `const_stable_indirect`. This is to make
// `#[rustc_const_stable_indirect]` an attribute that is always safe to add.
match tcx.lookup_const_stability(callee) {
None => {
// Non-const intrinsic.
self.check_op(ops::IntrinsicNonConst { name: intrinsic.name });
}
Some(ConstStability { feature: None, const_stable_indirect, .. }) => {
Some(ConstStability { feature: None, .. }) => {
// Intrinsic does not need a separate feature gate (we rely on the
// regular stability checker). However, we have to worry about recursive
// const stability.
if !const_stable_indirect && self.enforce_recursive_const_stability() {
if !intrinsic.const_stable && self.enforce_recursive_const_stability() {
self.dcx().emit_err(errors::UnmarkedIntrinsicExposed {
span: self.span,
def_path: self.tcx.def_path_str(callee),
@ -755,17 +758,17 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
Some(ConstStability {
feature: Some(feature),
level: StabilityLevel::Unstable { .. },
const_stable_indirect,
..
}) => {
self.check_op(ops::IntrinsicUnstable {
name: intrinsic.name,
feature,
const_stable_indirect,
const_stable: intrinsic.const_stable,
});
}
Some(ConstStability { level: StabilityLevel::Stable { .. }, .. }) => {
// All good.
// All good. But ensure this is indeed a const-stable intrinsic.
assert!(intrinsic.const_stable);
}
}
// This completes the checks for intrinsics.

4
compiler/rustc_const_eval/src/check_consts/ops.rs
View file

@ -354,14 +354,14 @@ impl<'tcx> NonConstOp<'tcx> for IntrinsicNonConst {
pub(crate) struct IntrinsicUnstable {
pub name: Symbol,
pub feature: Symbol,
pub const_stable_indirect: bool,
pub const_stable: bool,
}
impl<'tcx> NonConstOp<'tcx> for IntrinsicUnstable {
fn status_in_item(&self, _ccx: &ConstCx<'_, 'tcx>) -> Status {
Status::Unstable {
gate: self.feature,
safe_to_expose_on_stable: self.const_stable_indirect,
safe_to_expose_on_stable: self.const_stable,
// We do *not* want to suggest to mark the intrinsic as `const_stable_indirect`,
// that's not a trivial change!
is_function_call: false,