Rollup merge of #155629 - cijiugechu:fn_constness, r=makai410

rustc_public: Add `constness` & `asyncness` in `FnDef`

Resolves [https://github.com/rust-lang/project-stable-mir/issues/111](https://github.com/rust-lang/project-stable-mir/issues/111).

compiler/rustc_public/src/compiler_interface.rs

@@ -17,11 +17,11 @@
 use crate::mir::{BinOp, Body, Place, UnOp};
 use crate::target::{MachineInfo, MachineSize};
 use crate::ty::{
-    AdtDef, AdtKind, Allocation, ClosureDef, ClosureKind, CoroutineDef, Discr, FieldDef, FnDef,
-    ForeignDef, ForeignItemKind, ForeignModule, ForeignModuleDef, GenericArgs, GenericPredicates,
-    Generics, ImplDef, ImplTrait, IntrinsicDef, LineInfo, MirConst, PolyFnSig, RigidTy, Span,
-    TraitDecl, TraitDef, TraitRef, Ty, TyConst, TyConstId, TyKind, UintTy, VariantDef, VariantIdx,
-    VtblEntry,
+    AdtDef, AdtKind, Allocation, Asyncness, ClosureDef, ClosureKind, Constness, CoroutineDef,
+    Discr, FieldDef, FnDef, ForeignDef, ForeignItemKind, ForeignModule, ForeignModuleDef,
+    GenericArgs, GenericPredicates, Generics, ImplDef, ImplTrait, IntrinsicDef, LineInfo, MirConst,
+    PolyFnSig, RigidTy, Span, TraitDecl, TraitDef, TraitRef, Ty, TyConst, TyConstId, TyKind,
+    UintTy, VariantDef, VariantIdx, VtblEntry,
 };
 use crate::unstable::{RustcInternal, Stable, new_item_kind};
 use crate::{
@@ -388,6 +388,22 @@ pub(crate) fn fn_sig(&self, def: FnDef, args: &GenericArgs) -> PolyFnSig {
         cx.fn_sig(def_id, args_ref).stable(&mut *tables, cx)
     }
 
+    /// Retrieve the constness for the given function definition.
+    pub(crate) fn constness(&self, def: FnDef) -> Constness {
+        let mut tables = self.tables.borrow_mut();
+        let cx = &*self.cx.borrow();
+        let def_id = def.0.internal(&mut *tables, cx.tcx);
+        cx.constness(def_id).stable(&mut *tables, cx)
+    }
+
+    /// Retrieve the asyncness for the given function definition.
+    pub(crate) fn asyncness(&self, def: FnDef) -> Asyncness {
+        let mut tables = self.tables.borrow_mut();
+        let cx = &*self.cx.borrow();
+        let def_id = def.0.internal(&mut *tables, cx.tcx);
+        cx.asyncness(def_id).stable(&mut *tables, cx)
+    }
+
     /// Retrieve the intrinsic definition if the item corresponds one.
     pub(crate) fn intrinsic(&self, item: DefId) -> Option<IntrinsicDef> {
         let mut tables = self.tables.borrow_mut();

compiler/rustc_public/src/ty.rs

@@ -710,6 +710,16 @@ pub fn is_intrinsic(&self) -> bool {
         self.as_intrinsic().is_some()
     }
 
+    /// Get the constness of this function definition.
+    pub fn constness(&self) -> Constness {
+        with(|cx| cx.constness(*self))
+    }
+
+    /// Get the asyncness of this function definition.
+    pub fn asyncness(&self) -> Asyncness {
+        with(|cx| cx.asyncness(*self))
+    }
+
     /// Get the function signature for this function definition.
     pub fn fn_sig(&self) -> PolyFnSig {
         let kind = self.ty().kind();
@@ -1103,6 +1113,30 @@ pub fn inputs(&self) -> &[Ty] {
     }
 }
 
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Serialize)]
+pub enum Constness {
+    Const,
+    NotConst,
+}
+
+impl Constness {
+    pub fn is_const(self) -> bool {
+        matches!(self, Constness::Const)
+    }
+}
+
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Serialize)]
+pub enum Asyncness {
+    Async,
+    NotAsync,
+}
+
+impl Asyncness {
+    pub fn is_async(self) -> bool {
+        matches!(self, Asyncness::Async)
+    }
+}
+
 #[derive(Clone, PartialEq, Eq, Debug, Serialize)]
 pub enum Abi {
     Rust,

compiler/rustc_public/src/unstable/convert/internal.rs

@@ -14,8 +14,8 @@
 use crate::mir::mono::{Instance, MonoItem, StaticDef};
 use crate::mir::{BinOp, Mutability, Place, ProjectionElem, RawPtrKind, Safety, UnOp};
 use crate::ty::{
-    Abi, AdtDef, Binder, BoundRegionKind, BoundTyKind, BoundVariableKind, ClosureKind,
-    ExistentialPredicate, ExistentialProjection, ExistentialTraitRef, FloatTy, FnSig,
+    Abi, AdtDef, Asyncness, Binder, BoundRegionKind, BoundTyKind, BoundVariableKind, ClosureKind,
+    Constness, ExistentialPredicate, ExistentialProjection, ExistentialTraitRef, FloatTy, FnSig,
     GenericArgKind, GenericArgs, IntTy, MirConst, Movability, Pattern, Region, RigidTy, Span,
     TermKind, TraitRef, Ty, TyConst, UintTy, VariantDef, VariantIdx,
 };
@@ -637,6 +637,36 @@ fn internal<'tcx>(
         }
     }
 }
+
+impl RustcInternal for Constness {
+    type T<'tcx> = rustc_hir::Constness;
+
+    fn internal<'tcx>(
+        &self,
+        _tables: &mut Tables<'_, BridgeTys>,
+        _tcx: impl InternalCx<'tcx>,
+    ) -> Self::T<'tcx> {
+        match self {
+            Constness::Const => rustc_hir::Constness::Const,
+            Constness::NotConst => rustc_hir::Constness::NotConst,
+        }
+    }
+}
+
+impl RustcInternal for Asyncness {
+    type T<'tcx> = rustc_ty::Asyncness;
+
+    fn internal<'tcx>(
+        &self,
+        _tables: &mut Tables<'_, BridgeTys>,
+        _tcx: impl InternalCx<'tcx>,
+    ) -> Self::T<'tcx> {
+        match self {
+            Asyncness::Async => rustc_ty::Asyncness::Yes,
+            Asyncness::NotAsync => rustc_ty::Asyncness::No,
+        }
+    }
+}
 impl RustcInternal for Span {
     type T<'tcx> = rustc_span::Span;
 

compiler/rustc_public/src/unstable/convert/stable/mod.rs

@@ -21,6 +21,26 @@ fn stable(&self, _: &mut Tables<'_, BridgeTys>, _: &CompilerCtxt<'_, BridgeTys>)
     }
 }
 
+impl<'tcx> Stable<'tcx> for rustc_hir::Constness {
+    type T = crate::ty::Constness;
+    fn stable(&self, _: &mut Tables<'_, BridgeTys>, _: &CompilerCtxt<'_, BridgeTys>) -> Self::T {
+        match self {
+            rustc_hir::Constness::Const => crate::ty::Constness::Const,
+            rustc_hir::Constness::NotConst => crate::ty::Constness::NotConst,
+        }
+    }
+}
+
+impl<'tcx> Stable<'tcx> for rustc_middle::ty::Asyncness {
+    type T = crate::ty::Asyncness;
+    fn stable(&self, _: &mut Tables<'_, BridgeTys>, _: &CompilerCtxt<'_, BridgeTys>) -> Self::T {
+        match self {
+            rustc_middle::ty::Asyncness::Yes => crate::ty::Asyncness::Async,
+            rustc_middle::ty::Asyncness::No => crate::ty::Asyncness::NotAsync,
+        }
+    }
+}
+
 impl<'tcx> Stable<'tcx> for FieldIdx {
     type T = usize;
     fn stable(&self, _: &mut Tables<'_, BridgeTys>, _: &CompilerCtxt<'_, BridgeTys>) -> Self::T {

compiler/rustc_public_bridge/src/context/impls.rs

@@ -383,6 +383,16 @@ pub fn fn_sig(
         sig
     }
 
+    /// Retrieve the constness for the given function definition.
+    pub fn constness(&self, def_id: DefId) -> rustc_hir::Constness {
+        self.tcx.constness(def_id)
+    }
+
+    /// Retrieve the asyncness for the given function definition.
+    pub fn asyncness(&self, def_id: DefId) -> ty::Asyncness {
+        self.tcx.asyncness(def_id)
+    }
+
     /// Retrieve the intrinsic definition if the item corresponds one.
     pub fn intrinsic(&self, def_id: DefId) -> Option<IntrinsicDef> {
         let intrinsic = self.tcx.intrinsic_raw(def_id);

tests/ui-fulldeps/rustc_public/check_fn_attrs.rs

@@ -0,0 +1,93 @@
+//@ run-pass
+//! Test that users are able to query function-level constness and asyncness.
+
+//@ ignore-stage1
+//@ ignore-cross-compile
+//@ ignore-remote
+//@ edition: 2021
+
+#![feature(rustc_private)]
+
+extern crate rustc_driver;
+extern crate rustc_interface;
+extern crate rustc_middle;
+#[macro_use]
+extern crate rustc_public;
+
+use rustc_public::crate_def::CrateDef;
+use rustc_public::ty::{Asyncness, Constness, FnDef};
+use std::io::Write;
+use std::ops::ControlFlow;
+
+const CRATE_NAME: &str = "input";
+
+fn test_stable_mir() -> ControlFlow<()> {
+    let fns = rustc_public::local_crate().fn_defs();
+
+    check_fn(&fns, "input::const_sync", Constness::Const, Asyncness::NotAsync);
+    check_fn(&fns, "input::async_fn", Constness::NotConst, Asyncness::Async);
+    check_fn(&fns, "input::plain", Constness::NotConst, Asyncness::NotAsync);
+    check_fn(&fns, "input::Widget::assoc_const", Constness::Const, Asyncness::NotAsync);
+    check_fn(&fns, "input::Widget::assoc_async", Constness::NotConst, Asyncness::Async);
+    check_fn(&fns, "input::Widget::assoc_plain", Constness::NotConst, Asyncness::NotAsync);
+
+    ControlFlow::Continue(())
+}
+
+fn check_fn(fns: &[FnDef], name: &str, constness: Constness, asyncness: Asyncness) {
+    let fn_def =
+        fns.iter().find(|def| def.name() == name).unwrap_or_else(|| panic!("missing {name}"));
+    assert_eq!(fn_def.constness(), constness, "wrong constness for {}", fn_def.name());
+    assert_eq!(fn_def.asyncness(), asyncness, "wrong asyncness for {}", fn_def.name());
+}
+
+fn main() {
+    let path = "fn_attrs_input.rs";
+    generate_input(&path).unwrap();
+    let args = &[
+        "rustc".to_string(),
+        "--edition=2021".to_string(),
+        "--crate-type=lib".to_string(),
+        "--crate-name".to_string(),
+        CRATE_NAME.to_string(),
+        path.to_string(),
+    ];
+    run!(args, test_stable_mir).unwrap();
+}
+
+fn generate_input(path: &str) -> std::io::Result<()> {
+    let mut file = std::fs::File::create(path)?;
+    write!(
+        file,
+        r#"
+        pub const fn const_sync() -> u32 {{
+            1
+        }}
+
+        pub async fn async_fn() -> u32 {{
+            2
+        }}
+
+        pub fn plain() -> u32 {{
+            3
+        }}
+
+        pub struct Widget;
+
+        impl Widget {{
+            pub const fn assoc_const() -> u32 {{
+                4
+            }}
+
+            pub async fn assoc_async() -> u32 {{
+                5
+            }}
+
+            pub fn assoc_plain() -> u32 {{
+                6
+            }}
+        }}
+    "#
+    )?;
+    Ok(())
+}