Auto merge of rust-lang#116168 - matthiaskrgr:rollup-ys1zmk1, r=matth…

…iaskrgr

Rollup of 7 pull requests

Successful merges:

 - rust-lang#116099 (Add regression test for issue rust-lang#79865)
 - rust-lang#116102 (Correct codegen of `ConstValue::Indirect` scalar and scalar pair)
 - rust-lang#116131 (Rename `cold_path` to `outline`)
 - rust-lang#116144 (subst -> instantiate)
 - rust-lang#116151 (Fix typo in rustdoc unstable features doc)
 - rust-lang#116153 (Update books)
 - rust-lang#116162 (Gate and validate `#[rustc_safe_intrinsic]`)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_arena/src/lib.rs

@@ -37,9 +37,10 @@ use std::ptr::{self, NonNull};
 use std::slice;
 use std::{cmp, intrinsics};
 
+/// This calls the passed function while ensuring it won't be inlined into the caller.
 #[inline(never)]
 #[cold]
-fn cold_path<F: FnOnce() -> R, R>(f: F) -> R {
+fn outline<F: FnOnce() -> R, R>(f: F) -> R {
     f()
 }
 
@@ -600,7 +601,7 @@ impl DroplessArena {
                 unsafe { self.write_from_iter(iter, len, mem) }
             }
             (_, _) => {
-                cold_path(move || -> &mut [T] {
+                outline(move || -> &mut [T] {
                     let mut vec: SmallVec<[_; 8]> = iter.collect();
                     if vec.is_empty() {
                         return &mut [];

compiler/rustc_ast_lowering/src/lib.rs

@@ -1664,7 +1664,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     lifetime.ident,
                 ));
 
-                // Now make an arg that we can use for the substs of the opaque tykind.
+                // Now make an arg that we can use for the generic params of the opaque tykind.
                 let id = self.next_node_id();
                 let lifetime_arg = self.new_named_lifetime_with_res(id, lifetime.ident, res);
                 let duplicated_lifetime_def_id = self.local_def_id(duplicated_lifetime_node_id);

compiler/rustc_borrowck/src/diagnostics/region_name.rs

@@ -27,7 +27,7 @@ pub(crate) struct RegionName {
 /// This helps to print the right kinds of diagnostics.
 #[derive(Debug, Clone)]
 pub(crate) enum RegionNameSource {
-    /// A bound (not free) region that was substituted at the def site (not an HRTB).
+    /// A bound (not free) region that was instantiated at the def site (not an HRTB).
     NamedEarlyBoundRegion(Span),
     /// A free region that the user has a name (`'a`) for.
     NamedFreeRegion(Span),
@@ -619,7 +619,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
                     // programs, so we need to use delay_span_bug here. See #82126.
                     self.infcx.tcx.sess.delay_span_bug(
                         hir_arg.span(),
-                        format!("unmatched subst and hir arg: found {kind:?} vs {hir_arg:?}"),
+                        format!("unmatched arg and hir arg: found {kind:?} vs {hir_arg:?}"),
                     );
                 }
             }

compiler/rustc_borrowck/src/region_infer/mod.rs

@@ -2250,7 +2250,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
 
     pub(crate) fn universe_info(&self, universe: ty::UniverseIndex) -> UniverseInfo<'tcx> {
         // Query canonicalization can create local superuniverses (for example in
-        // `InferCtx::query_response_substitution_guess`), but they don't have an associated
+        // `InferCtx::query_response_instantiation_guess`), but they don't have an associated
         // `UniverseInfo` explaining why they were created.
         // This can cause ICEs if these causes are accessed in diagnostics, for example in issue
         // #114907 where this happens via liveness and dropck outlives results.

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -1007,7 +1007,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
     }
 
     pub(super) fn register_predefined_opaques_in_new_solver(&mut self) {
-        // OK to use the identity substitutions for each opaque type key, since
+        // OK to use the identity arguments for each opaque type key, since
         // we remap opaques from HIR typeck back to their definition params.
         let opaques: Vec<_> = self
             .infcx

compiler/rustc_borrowck/src/universal_regions.rs

@@ -639,10 +639,9 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
         };
 
         let global_mapping = iter::once((tcx.lifetimes.re_static, fr_static));
-        let subst_mapping =
-            iter::zip(identity_args.regions(), fr_args.regions().map(|r| r.as_var()));
+        let arg_mapping = iter::zip(identity_args.regions(), fr_args.regions().map(|r| r.as_var()));
 
-        UniversalRegionIndices { indices: global_mapping.chain(subst_mapping).collect(), fr_static }
+        UniversalRegionIndices { indices: global_mapping.chain(arg_mapping).collect(), fr_static }
     }
 
     fn compute_inputs_and_output(

compiler/rustc_codegen_cranelift/scripts/filter_profile.rs

@@ -100,9 +100,9 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
             stack = &stack[..index + ENCODE_METADATA.len()];
         }
 
-        const SUBST_AND_NORMALIZE_ERASING_REGIONS: &str = "rustc_middle::ty::normalize_erasing_regions::<impl rustc_middle::ty::context::TyCtxt>::subst_and_normalize_erasing_regions";
-        if let Some(index) = stack.find(SUBST_AND_NORMALIZE_ERASING_REGIONS) {
-            stack = &stack[..index + SUBST_AND_NORMALIZE_ERASING_REGIONS.len()];
+        const INSTANTIATE_AND_NORMALIZE_ERASING_REGIONS: &str = "rustc_middle::ty::normalize_erasing_regions::<impl rustc_middle::ty::context::TyCtxt>::instantiate_and_normalize_erasing_regions";
+        if let Some(index) = stack.find(INSTANTIATE_AND_NORMALIZE_ERASING_REGIONS) {
+            stack = &stack[..index + INSTANTIATE_AND_NORMALIZE_ERASING_REGIONS.len()];
         }
 
         const NORMALIZE_ERASING_LATE_BOUND_REGIONS: &str = "rustc_middle::ty::normalize_erasing_regions::<impl rustc_middle::ty::context::TyCtxt>::normalize_erasing_late_bound_regions";

compiler/rustc_codegen_cranelift/src/common.rs

@@ -359,7 +359,7 @@ impl<'tcx> FunctionCx<'_, '_, 'tcx> {
     where
         T: TypeFoldable<TyCtxt<'tcx>> + Copy,
     {
-        self.instance.subst_mir_and_normalize_erasing_regions(
+        self.instance.instantiate_mir_and_normalize_erasing_regions(
             self.tcx,
             ty::ParamEnv::reveal_all(),
             ty::EarlyBinder::bind(value),

compiler/rustc_codegen_llvm/src/debuginfo/create_scope_map.rs

@@ -90,7 +90,7 @@ fn make_mir_scope<'ll, 'tcx>(
         Some((callee, _)) => {
             // FIXME(eddyb) this would be `self.monomorphize(&callee)`
             // if this is moved to `rustc_codegen_ssa::mir::debuginfo`.
-            let callee = cx.tcx.subst_and_normalize_erasing_regions(
+            let callee = cx.tcx.instantiate_and_normalize_erasing_regions(
                 instance.args,
                 ty::ParamEnv::reveal_all(),
                 ty::EarlyBinder::bind(callee),

compiler/rustc_codegen_llvm/src/debuginfo/mod.rs

@@ -529,7 +529,7 @@ impl<'ll, 'tcx> DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
             if let Some(impl_def_id) = cx.tcx.impl_of_method(instance.def_id()) {
                 // If the method does *not* belong to a trait, proceed
                 if cx.tcx.trait_id_of_impl(impl_def_id).is_none() {
-                    let impl_self_ty = cx.tcx.subst_and_normalize_erasing_regions(
+                    let impl_self_ty = cx.tcx.instantiate_and_normalize_erasing_regions(
                         instance.args,
                         ty::ParamEnv::reveal_all(),
                         cx.tcx.type_of(impl_def_id),

compiler/rustc_codegen_ssa/src/mir/mod.rs

@@ -118,7 +118,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         T: Copy + TypeFoldable<TyCtxt<'tcx>>,
     {
         debug!("monomorphize: self.instance={:?}", self.instance);
-        self.instance.subst_mir_and_normalize_erasing_regions(
+        self.instance.instantiate_mir_and_normalize_erasing_regions(
             self.cx.tcx(),
             ty::ParamEnv::reveal_all(),
             ty::EarlyBinder::bind(value),

compiler/rustc_codegen_ssa/src/mir/operand.rs

@@ -135,15 +135,14 @@ impl<'a, 'tcx, V: CodegenObject> OperandRef<'tcx, V> {
         assert_eq!(alloc_align, layout.align.abi);
 
         let read_scalar = |start, size, s: abi::Scalar, ty| {
-            let val = alloc
-                .0
-                .read_scalar(
-                    bx,
-                    alloc_range(start, size),
-                    /*read_provenance*/ matches!(s.primitive(), abi::Pointer(_)),
-                )
-                .unwrap();
-            bx.scalar_to_backend(val, s, ty)
+            match alloc.0.read_scalar(
+                bx,
+                alloc_range(start, size),
+                /*read_provenance*/ matches!(s.primitive(), abi::Pointer(_)),
+            ) {
+                Ok(val) => bx.scalar_to_backend(val, s, ty),
+                Err(_) => bx.const_poison(ty),
+            }
         };
 
         // It may seem like all types with `Scalar` or `ScalarPair` ABI are fair game at this point.
@@ -156,18 +155,18 @@ impl<'a, 'tcx, V: CodegenObject> OperandRef<'tcx, V> {
             Abi::Scalar(s @ abi::Scalar::Initialized { .. }) => {
                 let size = s.size(bx);
                 assert_eq!(size, layout.size, "abi::Scalar size does not match layout size");
-                let val = read_scalar(Size::ZERO, size, s, bx.type_ptr());
+                let val = read_scalar(offset, size, s, bx.backend_type(layout));
                 OperandRef { val: OperandValue::Immediate(val), layout }
             }
             Abi::ScalarPair(
                 a @ abi::Scalar::Initialized { .. },
                 b @ abi::Scalar::Initialized { .. },
             ) => {
                 let (a_size, b_size) = (a.size(bx), b.size(bx));
-                let b_offset = a_size.align_to(b.align(bx).abi);
+                let b_offset = (offset + a_size).align_to(b.align(bx).abi);
                 assert!(b_offset.bytes() > 0);
                 let a_val = read_scalar(
-                    Size::ZERO,
+                    offset,
                     a_size,
                     a,
                     bx.scalar_pair_element_backend_type(layout, 0, true),

compiler/rustc_const_eval/src/interpret/eval_context.rs

@@ -569,7 +569,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
     ) -> Result<T, ErrorHandled> {
         frame
             .instance
-            .try_subst_mir_and_normalize_erasing_regions(
+            .try_instantiate_mir_and_normalize_erasing_regions(
                 *self.tcx,
                 self.param_env,
                 ty::EarlyBinder::bind(value),

compiler/rustc_const_eval/src/interpret/util.rs

@@ -4,7 +4,7 @@ use rustc_middle::ty::{
 };
 use std::ops::ControlFlow;
 
-/// Checks whether a type contains generic parameters which require substitution.
+/// Checks whether a type contains generic parameters which must be instantiated.
 ///
 /// In case it does, returns a `TooGeneric` const eval error. Note that due to polymorphization
 /// types may be "concrete enough" even though they still contain generic parameters in
@@ -43,7 +43,8 @@ where
                             .try_into()
                             .expect("more generic parameters than can fit into a `u32`");
                         // Only recurse when generic parameters in fns, closures and generators
-                        // are used and require substitution.
+                        // are used and have to be instantiated.
+                        //
                         // Just in case there are closures or generators within this subst,
                         // recurse.
                         if unused_params.is_used(index) && subst.has_param() {

compiler/rustc_const_eval/src/transform/validate.rs

@@ -558,8 +558,8 @@ impl<'a, 'tcx> Visitor<'tcx> for CfgChecker<'a, 'tcx> {
     }
 }
 
-/// A faster version of the validation pass that only checks those things which may break when apply
-/// generic substitutions.
+/// A faster version of the validation pass that only checks those things which may break when
+/// instantiating any generic parameters.
 pub fn validate_types<'tcx>(
     tcx: TyCtxt<'tcx>,
     mir_phase: MirPhase,

compiler/rustc_data_structures/src/lib.rs

@@ -51,9 +51,10 @@ use std::fmt;
 
 pub use rustc_index::static_assert_size;
 
+/// This calls the passed function while ensuring it won't be inlined into the caller.
 #[inline(never)]
 #[cold]
-pub fn cold_path<F: FnOnce() -> R, R>(f: F) -> R {
+pub fn outline<F: FnOnce() -> R, R>(f: F) -> R {
     f()
 }
 

compiler/rustc_data_structures/src/profiling.rs

@@ -81,8 +81,8 @@
 //!
 //! [mm]: https://github.com/rust-lang/measureme/
 
-use crate::cold_path;
 use crate::fx::FxHashMap;
+use crate::outline;
 
 use std::borrow::Borrow;
 use std::collections::hash_map::Entry;
@@ -697,7 +697,7 @@ impl<'a> TimingGuard<'a> {
     #[inline]
     pub fn finish_with_query_invocation_id(self, query_invocation_id: QueryInvocationId) {
         if let Some(guard) = self.0 {
-            cold_path(|| {
+            outline(|| {
                 let event_id = StringId::new_virtual(query_invocation_id.0);
                 let event_id = EventId::from_virtual(event_id);
                 guard.finish_with_override_event_id(event_id);

compiler/rustc_data_structures/src/sync/worker_local.rs

@@ -6,7 +6,7 @@ use std::ptr;
 use std::sync::Arc;
 
 #[cfg(parallel_compiler)]
-use {crate::cold_path, crate::sync::CacheAligned};
+use {crate::outline, crate::sync::CacheAligned};
 
 /// A pointer to the `RegistryData` which uniquely identifies a registry.
 /// This identifier can be reused if the registry gets freed.
@@ -25,11 +25,7 @@ impl RegistryId {
     fn verify(self) -> usize {
         let (id, index) = THREAD_DATA.with(|data| (data.registry_id.get(), data.index.get()));
 
-        if id == self {
-            index
-        } else {
-            cold_path(|| panic!("Unable to verify registry association"))
-        }
+        if id == self { index } else { outline(|| panic!("Unable to verify registry association")) }
     }
 }
 

compiler/rustc_error_codes/src/error_codes/E0038.md

@@ -162,14 +162,13 @@ fn foo<T>(x: T) {
 ```
 
 The machine code for `foo::<u8>()`, `foo::<bool>()`, `foo::<String>()`, or any
-other type substitution is different. Hence the compiler generates the
+other instantiation is different. Hence the compiler generates the
 implementation on-demand. If you call `foo()` with a `bool` parameter, the
 compiler will only generate code for `foo::<bool>()`. When we have additional
 type parameters, the number of monomorphized implementations the compiler
 generates does not grow drastically, since the compiler will only generate an
-implementation if the function is called with unparameterized substitutions
-(i.e., substitutions where none of the substituted types are themselves
-parameterized).
+implementation if the function is called with fully concrete arguments
+(i.e., arguments which do not contain any generic parameters).
 
 However, with trait objects we have to make a table containing _every_ object
 that implements the trait. Now, if it has type parameters, we need to add

compiler/rustc_error_codes/src/error_codes/E0094.md

@@ -3,7 +3,7 @@ An invalid number of generic parameters was passed to an intrinsic function.
 Erroneous code example:
 
 ```compile_fail,E0094
-#![feature(intrinsics)]
+#![feature(intrinsics, rustc_attrs)]
 #![allow(internal_features)]
 
 extern "rust-intrinsic" {
@@ -18,7 +18,7 @@ and verify with the function declaration in the Rust source code.
 Example:
 
 ```
-#![feature(intrinsics)]
+#![feature(intrinsics, rustc_attrs)]
 #![allow(internal_features)]
 
 extern "rust-intrinsic" {

compiler/rustc_error_codes/src/error_codes/E0211.md

@@ -4,7 +4,7 @@ You used a function or type which doesn't fit the requirements for where it was
 used. Erroneous code examples:
 
 ```compile_fail
-#![feature(intrinsics)]
+#![feature(intrinsics, rustc_attrs)]
 #![allow(internal_features)]
 
 extern "rust-intrinsic" {
@@ -41,7 +41,7 @@ impl Foo {
 For the first code example, please check the function definition. Example:
 
 ```
-#![feature(intrinsics)]
+#![feature(intrinsics, rustc_attrs)]
 #![allow(internal_features)]
 
 extern "rust-intrinsic" {

compiler/rustc_feature/src/builtin_attrs.rs

@@ -537,7 +537,6 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         allow_internal_unsafe, Normal, template!(Word), WarnFollowing,
         "allow_internal_unsafe side-steps the unsafe_code lint",
     ),
-    ungated!(rustc_safe_intrinsic, Normal, template!(Word), DuplicatesOk),
     rustc_attr!(rustc_allowed_through_unstable_modules, Normal, template!(Word), WarnFollowing,
     "rustc_allowed_through_unstable_modules special cases accidental stabilizations of stable items \
     through unstable paths"),
@@ -806,6 +805,10 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         rustc_doc_primitive, Normal, template!(NameValueStr: "primitive name"), ErrorFollowing,
         r#"`rustc_doc_primitive` is a rustc internal attribute"#,
     ),
+    rustc_attr!(
+        rustc_safe_intrinsic, Normal, template!(Word), WarnFollowing,
+        "the `#[rustc_safe_intrinsic]` attribute is used internally to mark intrinsics as safe"
+    ),
 
     // ==========================================================================
     // Internal attributes, Testing:

compiler/rustc_hir_analysis/src/astconv/bounds.rs

@@ -427,7 +427,7 @@ impl<'tcx> dyn AstConv<'tcx> + '_ {
             let bound_vars = tcx.late_bound_vars(binding.hir_id);
             ty::Binder::bind_with_vars(subst_output, bound_vars)
         } else {
-            // Include substitutions for generic parameters of associated types
+            // Append the generic arguments of the associated type to the `trait_ref`.
             candidate.map_bound(|trait_ref| {
                 let ident = Ident::new(assoc_item.name, binding.item_name.span);
                 let item_segment = hir::PathSegment {

compiler/rustc_hir_analysis/src/astconv/generics.rs

@@ -139,22 +139,22 @@ fn generic_arg_mismatch_err(
     err.emit()
 }
 
-/// Creates the relevant generic argument substitutions
+/// Creates the relevant generic arguments
 /// corresponding to a set of generic parameters. This is a
 /// rather complex function. Let us try to explain the role
 /// of each of its parameters:
 ///
-/// To start, we are given the `def_id` of the thing we are
-/// creating the substitutions for, and a partial set of
-/// substitutions `parent_args`. In general, the substitutions
-/// for an item begin with substitutions for all the "parents" of
+/// To start, we are given the `def_id` of the thing whose generic
+/// parameters we are instantiating, and a partial set of
+/// arguments `parent_args`. In general, the generic arguments
+/// for an item begin with arguments for all the "parents" of
 /// that item -- e.g., for a method it might include the
 /// parameters from the impl.
 ///
 /// Therefore, the method begins by walking down these parents,
 /// starting with the outermost parent and proceed inwards until
 /// it reaches `def_id`. For each parent `P`, it will check `parent_args`
-/// first to see if the parent's substitutions are listed in there. If so,
+/// first to see if the parent's arguments are listed in there. If so,
 /// we can append those and move on. Otherwise, it invokes the
 /// three callback functions:
 ///
@@ -188,15 +188,16 @@ pub fn create_args_for_parent_generic_args<'tcx, 'a>(
         stack.push((def_id, parent_defs));
     }
 
-    // We manually build up the substitution, rather than using convenience
+    // We manually build up the generic arguments, rather than using convenience
     // methods in `subst.rs`, so that we can iterate over the arguments and
     // parameters in lock-step linearly, instead of trying to match each pair.
     let mut args: SmallVec<[ty::GenericArg<'tcx>; 8]> = SmallVec::with_capacity(count);
     // Iterate over each segment of the path.
     while let Some((def_id, defs)) = stack.pop() {
         let mut params = defs.params.iter().peekable();
 
-        // If we have already computed substitutions for parents, we can use those directly.
+        // If we have already computed the generic arguments for parents,
+        // we can use those directly.
         while let Some(&param) = params.peek() {
             if let Some(&kind) = parent_args.get(param.index as usize) {
                 args.push(kind);