diff options
| -rw-r--r-- | src/librustc_mir/const_eval/fn_queries.rs | 149 |
1 files changed, 74 insertions, 75 deletions
diff --git a/src/librustc_mir/const_eval/fn_queries.rs b/src/librustc_mir/const_eval/fn_queries.rs index 1f7eb976902..27efcd50841 100644 --- a/src/librustc_mir/const_eval/fn_queries.rs +++ b/src/librustc_mir/const_eval/fn_queries.rs @@ -82,94 +82,93 @@ pub fn is_min_const_fn(tcx: TyCtxt<'_>, def_id: DefId) -> bool { } } -pub fn provide(providers: &mut Providers<'_>) { - /// Const evaluability whitelist is here to check evaluability at the - /// top level beforehand. - fn is_const_intrinsic(tcx: TyCtxt<'_>, def_id: DefId) -> Option<bool> { - if tcx.is_closure(def_id) { - return None; - } - - match tcx.fn_sig(def_id).abi() { - Abi::RustIntrinsic | Abi::PlatformIntrinsic => { - Some(tcx.lookup_const_stability(def_id).is_some()) - } - _ => None, - } +pub fn is_parent_const_impl_raw(tcx: TyCtxt<'_>, hir_id: hir::HirId) -> bool { + let parent_id = tcx.hir().get_parent_did(hir_id); + if !parent_id.is_top_level_module() { + is_const_impl_raw(tcx, LocalDefId::from_def_id(parent_id)) + } else { + false } +} - /// Checks whether the function has a `const` modifier or, in case it is an intrinsic, whether - /// said intrinsic is on the whitelist for being const callable. - fn is_const_fn_raw(tcx: TyCtxt<'_>, def_id: DefId) -> bool { - let hir_id = tcx - .hir() - .as_local_hir_id(def_id) - .expect("Non-local call to local provider is_const_fn"); - - let node = tcx.hir().get(hir_id); +/// Checks whether the function has a `const` modifier or, in case it is an intrinsic, whether +/// said intrinsic is on the whitelist for being const callable. +fn is_const_fn_raw(tcx: TyCtxt<'_>, def_id: DefId) -> bool { + let hir_id = + tcx.hir().as_local_hir_id(def_id).expect("Non-local call to local provider is_const_fn"); - if let Some(whitelisted) = is_const_intrinsic(tcx, def_id) { - whitelisted - } else if let Some(fn_like) = FnLikeNode::from_node(node) { - if fn_like.constness() == hir::Constness::Const { - return true; - } + let node = tcx.hir().get(hir_id); - // If the function itself is not annotated with `const`, it may still be a `const fn` - // if it resides in a const trait impl. - let parent_id = tcx.hir().get_parent_did(hir_id); - if def_id != parent_id && !parent_id.is_top_level_module() { - is_const_impl_raw(tcx, LocalDefId::from_def_id(parent_id)) - } else { - false - } - } else if let hir::Node::Ctor(_) = node { - true - } else { - false + if let Some(whitelisted) = is_const_intrinsic(tcx, def_id) { + whitelisted + } else if let Some(fn_like) = FnLikeNode::from_node(node) { + if fn_like.constness() == hir::Constness::Const { + return true; } + + // If the function itself is not annotated with `const`, it may still be a `const fn` + // if it resides in a const trait impl. + is_parent_const_impl_raw(tcx, hir_id) + } else if let hir::Node::Ctor(_) = node { + true + } else { + false } +} - /// Checks whether the given item is an `impl` that has a `const` modifier. - fn is_const_impl_raw(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool { - let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); - let node = tcx.hir().get(hir_id); - matches!( - node, - hir::Node::Item(hir::Item { - kind: hir::ItemKind::Impl { constness: hir::Constness::Const, .. }, - .. - }) - ) +/// Const evaluability whitelist is here to check evaluability at the +/// top level beforehand. +fn is_const_intrinsic(tcx: TyCtxt<'_>, def_id: DefId) -> Option<bool> { + if tcx.is_closure(def_id) { + return None; } - fn is_promotable_const_fn(tcx: TyCtxt<'_>, def_id: DefId) -> bool { - is_const_fn(tcx, def_id) - && match tcx.lookup_const_stability(def_id) { - Some(stab) => { - if cfg!(debug_assertions) && stab.promotable { - let sig = tcx.fn_sig(def_id); - assert_eq!( - sig.unsafety(), - hir::Unsafety::Normal, - "don't mark const unsafe fns as promotable", - // https://github.com/rust-lang/rust/pull/53851#issuecomment-418760682 - ); - } - stab.promotable + match tcx.fn_sig(def_id).abi() { + Abi::RustIntrinsic | Abi::PlatformIntrinsic => { + Some(tcx.lookup_const_stability(def_id).is_some()) + } + _ => None, + } +} + +/// Checks whether the given item is an `impl` that has a `const` modifier. +fn is_const_impl_raw(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool { + let hir_id = tcx.hir().local_def_id_to_hir_id(def_id); + let node = tcx.hir().get(hir_id); + matches!( + node, + hir::Node::Item(hir::Item { + kind: hir::ItemKind::Impl { constness: hir::Constness::Const, .. }, + .. + }) + ) +} + +fn is_promotable_const_fn(tcx: TyCtxt<'_>, def_id: DefId) -> bool { + is_const_fn(tcx, def_id) + && match tcx.lookup_const_stability(def_id) { + Some(stab) => { + if cfg!(debug_assertions) && stab.promotable { + let sig = tcx.fn_sig(def_id); + assert_eq!( + sig.unsafety(), + hir::Unsafety::Normal, + "don't mark const unsafe fns as promotable", + // https://github.com/rust-lang/rust/pull/53851#issuecomment-418760682 + ); } - None => false, + stab.promotable } - } + None => false, + } +} - fn const_fn_is_allowed_fn_ptr(tcx: TyCtxt<'_>, def_id: DefId) -> bool { - is_const_fn(tcx, def_id) - && tcx - .lookup_const_stability(def_id) - .map(|stab| stab.allow_const_fn_ptr) - .unwrap_or(false) - } +fn const_fn_is_allowed_fn_ptr(tcx: TyCtxt<'_>, def_id: DefId) -> bool { + is_const_fn(tcx, def_id) + && tcx.lookup_const_stability(def_id).map(|stab| stab.allow_const_fn_ptr).unwrap_or(false) +} +pub fn provide(providers: &mut Providers<'_>) { *providers = Providers { is_const_fn_raw, is_const_impl_raw: |tcx, def_id| is_const_impl_raw(tcx, LocalDefId::from_def_id(def_id)), |