Make is_intrinsic query return the intrinsic name

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -1650,16 +1650,9 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
 
         let func_ty = func.ty(body, self.infcx.tcx);
         if let ty::FnDef(def_id, _) = *func_ty.kind() {
-            if self.tcx().is_intrinsic(def_id) {
+            if let Some(sym::simd_shuffle) = self.tcx().intrinsic(def_id) {
-                match self.tcx().item_name(def_id) {
-                    sym::simd_shuffle => {
                 if !matches!(args[2], Spanned { node: Operand::Constant(_), .. }) {
-                            self.tcx()
+                    self.tcx().dcx().emit_err(SimdShuffleLastConst { span: term.source_info.span });
-                                .dcx()
-                                .emit_err(SimdShuffleLastConst { span: term.source_info.span });
-                        }
-                    }
-                    _ => {}
                 }
             }
         }

compiler/rustc_const_eval/src/const_eval/fn_queries.rs

@@ -49,7 +49,7 @@ fn constness(tcx: TyCtxt<'_>, def_id: LocalDefId) -> hir::Constness {
         hir::Node::ForeignItem(hir::ForeignItem { kind: hir::ForeignItemKind::Fn(..), .. }) => {
             // Intrinsics use `rustc_const_{un,}stable` attributes to indicate constness. All other
             // foreign items cannot be evaluated at compile-time.
-            let is_const = if tcx.is_intrinsic(def_id) {
+            let is_const = if tcx.intrinsic(def_id).is_some() {
                 tcx.lookup_const_stability(def_id).is_some()
             } else {
                 false

compiler/rustc_const_eval/src/interpret/terminator.rs

@@ -526,7 +526,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
 
         match instance.def {
             ty::InstanceDef::Intrinsic(def_id) => {
-                assert!(self.tcx.is_intrinsic(def_id));
+                assert!(self.tcx.intrinsic(def_id).is_some());
                 // FIXME: Should `InPlace` arguments be reset to uninit?
                 M::call_intrinsic(
                     self,

compiler/rustc_const_eval/src/transform/check_consts/check.rs

@@ -859,7 +859,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
                     // We do not use `const` modifiers for intrinsic "functions", as intrinsics are
                     // `extern` functions, and these have no way to get marked `const`. So instead we
                     // use `rustc_const_(un)stable` attributes to mean that the intrinsic is `const`
-                    if self.ccx.is_const_stable_const_fn() || tcx.is_intrinsic(callee) {
+                    if self.ccx.is_const_stable_const_fn() || tcx.intrinsic(callee).is_some() {
                         self.check_op(ops::FnCallUnstable(callee, None));
                         return;
                     }

compiler/rustc_hir_typeck/src/callee.rs

@@ -540,8 +540,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         if let Some(def_id) = def_id
             && self.tcx.def_kind(def_id) == hir::def::DefKind::Fn
-            && self.tcx.is_intrinsic(def_id)
+            && matches!(self.tcx.intrinsic(def_id), Some(sym::const_eval_select))
-            && self.tcx.item_name(def_id) == sym::const_eval_select
         {
             let fn_sig = self.resolve_vars_if_possible(fn_sig);
             for idx in 0..=1 {

compiler/rustc_hir_typeck/src/coercion.rs

@@ -864,7 +864,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
                 let a_sig = a.fn_sig(self.tcx);
                 if let ty::FnDef(def_id, _) = *a.kind() {
                     // Intrinsics are not coercible to function pointers
-                    if self.tcx.is_intrinsic(def_id) {
+                    if self.tcx.intrinsic(def_id).is_some() {
                         return Err(TypeError::IntrinsicCast);
                     }
 

compiler/rustc_infer/src/infer/error_reporting/suggest.rs

@@ -313,7 +313,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
 
                 if !self.same_type_modulo_infer(*found_sig, *expected_sig)
                     || !sig.is_suggestable(self.tcx, true)
-                    || self.tcx.is_intrinsic(*did)
+                    || self.tcx.intrinsic(*did).is_some()
                 {
                     return;
                 }
@@ -345,8 +345,8 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                 if !self.same_type_modulo_infer(*found_sig, *expected_sig)
                     || !found_sig.is_suggestable(self.tcx, true)
                     || !expected_sig.is_suggestable(self.tcx, true)
-                    || self.tcx.is_intrinsic(*did1)
+                    || self.tcx.intrinsic(*did1).is_some()
-                    || self.tcx.is_intrinsic(*did2)
+                    || self.tcx.intrinsic(*did2).is_some()
                 {
                     return;
                 }

compiler/rustc_lint/src/builtin.rs

@@ -1227,7 +1227,7 @@ impl<'tcx> LateLintPass<'tcx> for MutableTransmutes {
         }
 
         fn def_id_is_transmute(cx: &LateContext<'_>, def_id: DefId) -> bool {
-            cx.tcx.is_intrinsic(def_id) && cx.tcx.item_name(def_id) == sym::transmute
+            matches!(cx.tcx.intrinsic(def_id), Some(sym::transmute))
         }
     }
 }

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -1746,8 +1746,8 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
         self.root.tables.attr_flags.get(self, index)
     }
 
-    fn get_is_intrinsic(self, index: DefIndex) -> bool {
+    fn get_intrinsic(self, index: DefIndex) -> bool {
-        self.root.tables.is_intrinsic.get(self, index)
+        self.root.tables.intrinsic.get(self, index)
     }
 
     fn get_doc_link_resolutions(self, index: DefIndex) -> DocLinkResMap {

compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs

@@ -348,7 +348,7 @@ provide! { tcx, def_id, other, cdata,
         cdata.get_stability_implications(tcx).iter().copied().collect()
     }
     stripped_cfg_items => { cdata.get_stripped_cfg_items(cdata.cnum, tcx) }
-    is_intrinsic => { cdata.get_is_intrinsic(def_id.index) }
+    intrinsic => { cdata.get_intrinsic(def_id.index).then(|| tcx.item_name(def_id)) }
     defined_lang_items => { cdata.get_lang_items(tcx) }
     diagnostic_items => { cdata.get_diagnostic_items() }
     missing_lang_items => { cdata.get_missing_lang_items(tcx) }

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1411,7 +1411,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             if let DefKind::Fn | DefKind::AssocFn = def_kind {
                 self.tables.asyncness.set_some(def_id.index, tcx.asyncness(def_id));
                 record_array!(self.tables.fn_arg_names[def_id] <- tcx.fn_arg_names(def_id));
-                self.tables.is_intrinsic.set(def_id.index, tcx.is_intrinsic(def_id));
+                self.tables.intrinsic.set(def_id.index, tcx.intrinsic(def_id).is_some());
             }
             if let DefKind::TyParam = def_kind {
                 let default = self.tcx.object_lifetime_default(def_id);

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -375,7 +375,7 @@ macro_rules! define_tables {
 
 define_tables! {
 - defaulted:
-    is_intrinsic: Table<DefIndex, bool>,
+    intrinsic: Table<DefIndex, bool>,
     is_macro_rules: Table<DefIndex, bool>,
     is_type_alias_impl_trait: Table<DefIndex, bool>,
     type_alias_is_lazy: Table<DefIndex, bool>,

compiler/rustc_middle/src/query/erase.rs

@@ -240,6 +240,7 @@ trivial! {
     Option<rustc_span::Span>,
     Option<rustc_target::spec::PanicStrategy>,
     Option<usize>,
+    Option<rustc_span::Symbol>,
     Result<(), rustc_errors::ErrorGuaranteed>,
     Result<(), rustc_middle::traits::query::NoSolution>,
     Result<rustc_middle::traits::EvaluationResult, rustc_middle::traits::OverflowError>,

compiler/rustc_middle/src/query/mod.rs

@@ -1753,8 +1753,8 @@ rustc_queries! {
         separate_provide_extern
     }
     /// Whether the function is an intrinsic
-    query is_intrinsic(def_id: DefId) -> bool {
+    query intrinsic(def_id: DefId) -> Option<Symbol> {
-        desc { |tcx| "checking whether `{}` is an intrinsic", tcx.def_path_str(def_id) }
+        desc { |tcx| "fetch intrinsic name if `{}` is an intrinsic", tcx.def_path_str(def_id) }
         separate_provide_extern
     }
     /// Returns the lang items defined in another crate by loading it from metadata.

compiler/rustc_middle/src/ty/util.rs

@@ -18,7 +18,7 @@ use rustc_hir::def_id::{CrateNum, DefId, LocalDefId};
 use rustc_index::bit_set::GrowableBitSet;
 use rustc_macros::HashStable;
 use rustc_session::Limit;
-use rustc_span::sym;
+use rustc_span::{sym, Symbol};
 use rustc_target::abi::{Integer, IntegerType, Primitive, Size};
 use rustc_target::spec::abi::Abi;
 use smallvec::SmallVec;
@@ -1550,8 +1550,13 @@ pub fn is_doc_notable_trait(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
 }
 
 /// Determines whether an item is an intrinsic by Abi.
-pub fn is_intrinsic(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool {
+pub fn intrinsic(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<Symbol> {
-    matches!(tcx.fn_sig(def_id).skip_binder().abi(), Abi::RustIntrinsic | Abi::PlatformIntrinsic)
+    if matches!(tcx.fn_sig(def_id).skip_binder().abi(), Abi::RustIntrinsic | Abi::PlatformIntrinsic)
+    {
+        Some(tcx.item_name(def_id.into()))
+    } else {
+        None
+    }
 }
 
 pub fn provide(providers: &mut Providers) {
@@ -1559,7 +1564,7 @@ pub fn provide(providers: &mut Providers) {
         reveal_opaque_types_in_bounds,
         is_doc_hidden,
         is_doc_notable_trait,
-        is_intrinsic,
+        intrinsic,
         ..*providers
     }
 }

compiler/rustc_mir_dataflow/src/rustc_peek.rs

@@ -202,8 +202,7 @@ impl PeekCall {
             &terminator.kind
         {
             if let ty::FnDef(def_id, fn_args) = *func.const_.ty().kind() {
-                let name = tcx.item_name(def_id);
+                if tcx.intrinsic(def_id)? != sym::rustc_peek {
-                if !tcx.is_intrinsic(def_id) || name != sym::rustc_peek {
                     return None;
                 }
 

compiler/rustc_mir_transform/src/cost_checker.rs

@@ -70,7 +70,7 @@ impl<'tcx> Visitor<'tcx> for CostChecker<'_, 'tcx> {
             TerminatorKind::Call { func: Operand::Constant(ref f), unwind, .. } => {
                 let fn_ty = self.instantiate_ty(f.const_.ty());
                 self.cost += if let ty::FnDef(def_id, _) = *fn_ty.kind()
-                    && tcx.is_intrinsic(def_id)
+                    && tcx.intrinsic(def_id).is_some()
                 {
                     // Don't give intrinsics the extra penalty for calls
                     INSTR_COST

compiler/rustc_mir_transform/src/instsimplify.rs

@@ -329,9 +329,8 @@ fn resolve_rust_intrinsic<'tcx>(
     func_ty: Ty<'tcx>,
 ) -> Option<(Symbol, GenericArgsRef<'tcx>)> {
     if let ty::FnDef(def_id, args) = *func_ty.kind() {
-        if tcx.is_intrinsic(def_id) {
+        let name = tcx.intrinsic(def_id)?;
-            return Some((tcx.item_name(def_id), args));
+        return Some((name, args));
-        }
     }
     None
 }

compiler/rustc_mir_transform/src/lib.rs

@@ -161,8 +161,7 @@ fn remap_mir_for_const_eval_select<'tcx>(
                 fn_span,
                 ..
             } if let ty::FnDef(def_id, _) = *const_.ty().kind()
-                && tcx.item_name(def_id) == sym::const_eval_select
+                && matches!(tcx.intrinsic(def_id), Some(sym::const_eval_select)) =>
-                && tcx.is_intrinsic(def_id) =>
             {
                 let [tupled_args, called_in_const, called_at_rt]: [_; 3] =
                     std::mem::take(args).try_into().unwrap();

compiler/rustc_mir_transform/src/lower_intrinsics.rs

@@ -14,9 +14,8 @@ impl<'tcx> MirPass<'tcx> for LowerIntrinsics {
             if let TerminatorKind::Call { func, args, destination, target, .. } =
                 &mut terminator.kind
                 && let ty::FnDef(def_id, generic_args) = *func.ty(local_decls, tcx).kind()
-                && tcx.is_intrinsic(def_id)
+                && let Some(intrinsic_name) = tcx.intrinsic(def_id)
             {
-                let intrinsic_name = tcx.item_name(def_id);
                 match intrinsic_name {
                     sym::unreachable => {
                         terminator.kind = TerminatorKind::Unreachable;

compiler/rustc_ty_utils/src/instance.rs

@@ -28,7 +28,8 @@ fn resolve_instance<'tcx>(
             tcx.normalize_erasing_regions(param_env, args),
         )
     } else {
-        let def = if matches!(tcx.def_kind(def_id), DefKind::Fn) && tcx.is_intrinsic(def_id) {
+        let def = if matches!(tcx.def_kind(def_id), DefKind::Fn) && tcx.intrinsic(def_id).is_some()
+        {
             debug!(" => intrinsic");
             ty::InstanceDef::Intrinsic(def_id)
         } else if Some(def_id) == tcx.lang_items().drop_in_place_fn() {

src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs

@@ -335,7 +335,7 @@ fn check_terminator<'tcx>(
                 // within const fns. `transmute` is allowed in all other const contexts.
                 // This won't really scale to more intrinsics or functions. Let's allow const
                 // transmutes in const fn before we add more hacks to this.
-                if tcx.is_intrinsic(fn_def_id) && tcx.item_name(fn_def_id) == sym::transmute {
+                if matches!(tcx.intrinsic(fn_def_id), Some(sym::transmute)) {
                     return Err((
                         span,
                         "can only call `transmute` from const items, not `const fn`".into(),