Add intrinsic definition and retrieval APIs

compiler/rustc_smir/src/rustc_smir/context.rs

@@ -23,8 +23,8 @@ use stable_mir::mir::{BinOp, Body, Place};
 use stable_mir::target::{MachineInfo, MachineSize};
 use stable_mir::ty::{
     AdtDef, AdtKind, Allocation, ClosureDef, ClosureKind, Const, FieldDef, FnDef, ForeignDef,
-    ForeignItemKind, GenericArgs, LineInfo, PolyFnSig, RigidTy, Span, Ty, TyKind, UintTy,
-    VariantDef,
+    ForeignItemKind, GenericArgs, IntrinsicDef, LineInfo, PolyFnSig, RigidTy, Span, Ty, TyKind,
+    UintTy, VariantDef,
 };
 use stable_mir::{Crate, CrateDef, CrateItem, CrateNum, DefId, Error, Filename, ItemKind, Symbol};
 use std::cell::RefCell;
@@ -307,6 +307,28 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
         sig.stable(&mut *tables)
     }
 
+    fn intrinsic(&self, def: DefId) -> Option<IntrinsicDef> {
+        let mut tables = self.0.borrow_mut();
+        let tcx = tables.tcx;
+        let def_id = def.internal(&mut *tables, tcx);
+        let intrinsic = tcx.intrinsic_raw(def_id);
+        intrinsic.map(|_| IntrinsicDef(def))
+    }
+
+    fn intrinsic_name(&self, def: IntrinsicDef) -> Symbol {
+        let mut tables = self.0.borrow_mut();
+        let tcx = tables.tcx;
+        let def_id = def.0.internal(&mut *tables, tcx);
+        tcx.intrinsic(def_id).unwrap().name.to_string()
+    }
+
+    fn intrinsic_must_be_overridden(&self, def: IntrinsicDef) -> bool {
+        let mut tables = self.0.borrow_mut();
+        let tcx = tables.tcx;
+        let def_id = def.0.internal(&mut *tables, tcx);
+        tcx.intrinsic_raw(def_id).unwrap().must_be_overridden
+    }
+
     fn closure_sig(&self, args: &GenericArgs) -> PolyFnSig {
         let mut tables = self.0.borrow_mut();
         let tcx = tables.tcx;
@@ -645,16 +667,6 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
         }
     }
 
-    /// Retrieve the plain intrinsic name of an instance.
-    ///
-    /// This assumes that the instance is an intrinsic.
-    fn intrinsic_name(&self, def: InstanceDef) -> Symbol {
-        let tables = self.0.borrow_mut();
-        let instance = tables.instances[def];
-        let intrinsic = tables.tcx.intrinsic(instance.def_id()).unwrap();
-        intrinsic.name.to_string()
-    }
-
     fn ty_layout(&self, ty: Ty) -> Result<Layout, Error> {
         let mut tables = self.0.borrow_mut();
         let tcx = tables.tcx;

compiler/stable_mir/src/compiler_interface.rs

@@ -13,8 +13,8 @@ use crate::target::MachineInfo;
 use crate::ty::{
     AdtDef, AdtKind, Allocation, ClosureDef, ClosureKind, Const, FieldDef, FnDef, ForeignDef,
     ForeignItemKind, ForeignModule, ForeignModuleDef, GenericArgs, GenericPredicates, Generics,
-    ImplDef, ImplTrait, LineInfo, PolyFnSig, RigidTy, Span, TraitDecl, TraitDef, Ty, TyKind,
-    UintTy, VariantDef,
+    ImplDef, ImplTrait, IntrinsicDef, LineInfo, PolyFnSig, RigidTy, Span, TraitDecl, TraitDef, Ty,
+    TyKind, UintTy, VariantDef,
 };
 use crate::{
     mir, Crate, CrateItem, CrateItems, CrateNum, DefId, Error, Filename, ImplTraitDecls, ItemKind,
@@ -88,6 +88,16 @@ pub trait Context {
     /// Retrieve the function signature for the given generic arguments.
     fn fn_sig(&self, def: FnDef, args: &GenericArgs) -> PolyFnSig;
 
+    /// Retrieve the intrinsic definition if the item corresponds one.
+    fn intrinsic(&self, item: DefId) -> Option<IntrinsicDef>;
+
+    /// Retrieve the plain function name of an intrinsic.
+    fn intrinsic_name(&self, def: IntrinsicDef) -> Symbol;
+
+    /// Returns whether the intrinsic has no meaningful body and all backends
+    /// need to shim all calls to it.
+    fn intrinsic_must_be_overridden(&self, def: IntrinsicDef) -> bool;
+
     /// Retrieve the closure signature for the given generic arguments.
     fn closure_sig(&self, args: &GenericArgs) -> PolyFnSig;
 
@@ -198,7 +208,6 @@ pub trait Context {
     fn vtable_allocation(&self, global_alloc: &GlobalAlloc) -> Option<AllocId>;
     fn krate(&self, def_id: DefId) -> Crate;
     fn instance_name(&self, def: InstanceDef, trimmed: bool) -> Symbol;
-    fn intrinsic_name(&self, def: InstanceDef) -> Symbol;
 
     /// Return information about the target machine.
     fn target_info(&self) -> MachineInfo;

compiler/stable_mir/src/mir/mono.rs

@@ -106,7 +106,9 @@ impl Instance {
     /// which is more convenient to match with intrinsic symbols.
     pub fn intrinsic_name(&self) -> Option<Symbol> {
         match self.kind {
-            InstanceKind::Intrinsic => Some(with(|context| context.intrinsic_name(self.def))),
+            InstanceKind::Intrinsic => {
+                Some(with(|context| context.intrinsic(self.def.def_id()).unwrap().fn_name()))
+            }
             InstanceKind::Item | InstanceKind::Virtual { .. } | InstanceKind::Shim => None,
         }
     }

compiler/stable_mir/src/ty.rs

@@ -622,6 +622,35 @@ impl FnDef {
     pub fn body(&self) -> Option<Body> {
         with(|ctx| ctx.has_body(self.0).then(|| ctx.mir_body(self.0)))
     }
+
+    /// Get the information of the intrinsic if this function is a definition of one.
+    pub fn as_intrinsic(&self) -> Option<IntrinsicDef> {
+        with(|cx| cx.intrinsic(self.def_id()))
+    }
+
+    /// Check if the function is an intrinsic.
+    #[inline]
+    pub fn is_intrinsic(&self) -> bool {
+        self.as_intrinsic().is_some()
+    }
+}
+
+crate_def! {
+    pub IntrinsicDef;
+}
+
+impl IntrinsicDef {
+    /// Returns the plain name of the intrinsic.
+    /// e.g., `transmute` for `core::intrinsics::transmute`.
+    pub fn fn_name(&self) -> Symbol {
+        with(|cx| cx.intrinsic_name(*self))
+    }
+
+    /// Returns whether the intrinsic has no meaningful body and all backends
+    /// need to shim all calls to it.
+    pub fn must_be_overridden(&self) -> bool {
+        with(|cx| cx.intrinsic_must_be_overridden(*self))
+    }
 }
 
 crate_def! {