Auto merge of #97012 - oli-obk:🦀_intrinsics, r=davidtwco

Add a query for checking whether a function is an intrinsic.

work towards #93145

This will reduce churn when we add more ways to declare intrinsics

r? `@scottmcm`

Author: bors

compiler/rustc_const_eval/src/const_eval/fn_queries.rs

@@ -4,7 +4,6 @@ use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{DefIdTree, TyCtxt};
 use rustc_span::symbol::Symbol;
-use rustc_target::spec::abi::Abi;
 
 /// Whether the `def_id` is an unstable const fn and what feature gate is necessary to enable it
 pub fn is_unstable_const_fn(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Symbol> {
@@ -34,10 +33,7 @@ fn impl_constness(tcx: TyCtxt<'_>, def_id: DefId) -> 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 hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
-            let is_const = if let Abi::RustIntrinsic | Abi::PlatformIntrinsic =
-                tcx.hir().get_foreign_abi(hir_id)
-            {
+            let is_const = if tcx.is_intrinsic(def_id) {
                 tcx.lookup_const_stability(def_id).is_some()
             } else {
                 false

compiler/rustc_const_eval/src/interpret/terminator.rs

@@ -312,8 +312,8 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         };
 
         match instance.def {
-            ty::InstanceDef::Intrinsic(..) => {
-                assert!(caller_abi == Abi::RustIntrinsic || caller_abi == Abi::PlatformIntrinsic);
+            ty::InstanceDef::Intrinsic(def_id) => {
+                assert!(self.tcx.is_intrinsic(def_id));
                 // caller_fn_abi is not relevant here, we interpret the arguments directly for each intrinsic.
                 M::call_intrinsic(self, instance, args, ret, unwind)
             }

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

@@ -702,8 +702,6 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
 
     #[instrument(level = "debug", skip(self))]
     fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
-        use rustc_target::spec::abi::Abi::RustIntrinsic;
-
         self.super_terminator(terminator, location);
 
         match &terminator.kind {
@@ -885,7 +883,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
                     return;
                 }
 
-                let is_intrinsic = tcx.fn_sig(callee).abi() == RustIntrinsic;
+                let is_intrinsic = tcx.is_intrinsic(callee);
 
                 if !tcx.is_const_fn_raw(callee) {
                     if tcx.trait_of_item(callee).is_some() {

compiler/rustc_lint/src/builtin.rs

@@ -1252,7 +1252,6 @@ declare_lint_pass!(MutableTransmutes => [MUTABLE_TRANSMUTES]);
 
 impl<'tcx> LateLintPass<'tcx> for MutableTransmutes {
     fn check_expr(&mut self, cx: &LateContext<'_>, expr: &hir::Expr<'_>) {
-        use rustc_target::spec::abi::Abi::RustIntrinsic;
         if let Some((&ty::Ref(_, _, from_mt), &ty::Ref(_, _, to_mt))) =
             get_transmute_from_to(cx, expr).map(|(ty1, ty2)| (ty1.kind(), ty2.kind()))
         {
@@ -1287,8 +1286,7 @@ impl<'tcx> LateLintPass<'tcx> for MutableTransmutes {
         }
 
         fn def_id_is_transmute(cx: &LateContext<'_>, def_id: DefId) -> bool {
-            cx.tcx.fn_sig(def_id).abi() == RustIntrinsic
-                && cx.tcx.item_name(def_id) == sym::transmute
+            cx.tcx.is_intrinsic(def_id) && cx.tcx.item_name(def_id) == sym::transmute
         }
     }
 }

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -1752,6 +1752,10 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
     fn get_may_have_doc_links(self, index: DefIndex) -> bool {
         self.root.tables.may_have_doc_links.get(self, index).is_some()
     }
+
+    fn get_is_intrinsic(self, index: DefIndex) -> bool {
+        self.root.tables.is_intrinsic.get(self, index).is_some()
+    }
 }
 
 impl CrateMetadata {

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

@@ -224,6 +224,7 @@ provide! { <'tcx> tcx, def_id, other, cdata,
         tcx.arena.alloc_slice(&result)
     }
     defined_lib_features => { cdata.get_lib_features(tcx) }
+    is_intrinsic => { cdata.get_is_intrinsic(def_id.index) }
     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

@@ -1318,6 +1318,9 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         }
         if impl_item.kind == ty::AssocKind::Fn {
             record!(self.tables.fn_sig[def_id] <- tcx.fn_sig(def_id));
+            if tcx.is_intrinsic(def_id) {
+                self.tables.is_intrinsic.set(def_id.index, ());
+            }
         }
     }
 
@@ -1562,6 +1565,9 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         }
         if let hir::ItemKind::Fn(..) = item.kind {
             record!(self.tables.fn_sig[def_id] <- tcx.fn_sig(def_id));
+            if tcx.is_intrinsic(def_id) {
+                self.tables.is_intrinsic.set(def_id.index, ());
+            }
         }
         if let hir::ItemKind::Impl { .. } = item.kind {
             if let Some(trait_ref) = self.tcx.impl_trait_ref(def_id) {
@@ -1958,6 +1964,9 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         self.encode_item_type(def_id);
         if let hir::ForeignItemKind::Fn(..) = nitem.kind {
             record!(self.tables.fn_sig[def_id] <- tcx.fn_sig(def_id));
+            if tcx.is_intrinsic(def_id) {
+                self.tables.is_intrinsic.set(def_id.index, ());
+            }
         }
     }
 }

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -340,6 +340,7 @@ define_tables! {
     impl_parent: Table<DefIndex, RawDefId>,
     impl_polarity: Table<DefIndex, ty::ImplPolarity>,
     impl_constness: Table<DefIndex, hir::Constness>,
+    is_intrinsic: Table<DefIndex, ()>,
     impl_defaultness: Table<DefIndex, hir::Defaultness>,
     // FIXME(eddyb) perhaps compute this on the fly if cheap enough?
     coerce_unsized_info: Table<DefIndex, Lazy!(ty::adjustment::CoerceUnsizedInfo)>,

compiler/rustc_middle/src/query/mod.rs

@@ -1601,6 +1601,11 @@ rustc_queries! {
         desc { "calculating the lib features defined in a crate" }
         separate_provide_extern
     }
+    /// Whether the function is an intrinsic
+    query is_intrinsic(def_id: DefId) -> bool {
+        desc { |tcx| "is_intrinsic({})", tcx.def_path_str(def_id) }
+        separate_provide_extern
+    }
     /// Returns the lang items defined in another crate by loading it from metadata.
     query get_lang_items(_: ()) -> LanguageItems {
         storage(ArenaCacheSelector<'tcx>)

compiler/rustc_middle/src/ty/util.rs

@@ -21,6 +21,7 @@ use rustc_hir::def_id::DefId;
 use rustc_macros::HashStable;
 use rustc_span::{sym, DUMMY_SP};
 use rustc_target::abi::{Integer, Size, TargetDataLayout};
+use rustc_target::spec::abi::Abi;
 use smallvec::SmallVec;
 use std::{fmt, iter};
 
@@ -1195,6 +1196,12 @@ pub fn is_doc_hidden(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
         .any(|items| items.iter().any(|item| item.has_name(sym::hidden)))
 }
 
+/// Determines whether an item is an intrinsic by Abi.
+pub fn is_intrinsic(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
+    matches!(tcx.fn_sig(def_id).abi(), Abi::RustIntrinsic | Abi::PlatformIntrinsic)
+}
+
 pub fn provide(providers: &mut ty::query::Providers) {
-    *providers = ty::query::Providers { normalize_opaque_types, is_doc_hidden, ..*providers }
+    *providers =
+        ty::query::Providers { normalize_opaque_types, is_doc_hidden, is_intrinsic, ..*providers }
 }