Auto merge of #116175 - matthiaskrgr:rollup-cwteiwy, r=matthiaskrgr

Rollup of 5 pull requests

Successful merges:

 - #116099 (Add regression test for issue #79865)
 - #116131 (Rename `cold_path` to `outline`)
 - #116151 (Fix typo in rustdoc unstable features doc)
 - #116153 (Update books)
 - #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_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/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_passes/messages.ftl

@@ -648,6 +648,10 @@ passes_rustc_lint_opt_ty =
     `#[rustc_lint_opt_ty]` should be applied to a struct
     .label = not a struct
 
+passes_rustc_safe_intrinsic =
+    attribute should be applied to intrinsic functions
+    .label = not an intrinsic function
+
 passes_rustc_std_internal_symbol =
     attribute should be applied to functions or statics
     .label = not a function or static

compiler/rustc_passes/src/check_attr.rs

@@ -195,6 +195,9 @@ impl CheckAttrVisitor<'_> {
                 | sym::rustc_promotable => self.check_stability_promotable(&attr, span, target),
                 sym::link_ordinal => self.check_link_ordinal(&attr, span, target),
                 sym::rustc_confusables => self.check_confusables(&attr, target),
+                sym::rustc_safe_intrinsic => {
+                    self.check_rustc_safe_intrinsic(hir_id, attr, span, target)
+                }
                 _ => true,
             };
 
@@ -2042,6 +2045,29 @@ impl CheckAttrVisitor<'_> {
         }
     }
 
+    fn check_rustc_safe_intrinsic(
+        &self,
+        hir_id: HirId,
+        attr: &Attribute,
+        span: Span,
+        target: Target,
+    ) -> bool {
+        let hir = self.tcx.hir();
+
+        if let Target::ForeignFn = target
+            && let Some(parent) = hir.opt_parent_id(hir_id)
+            && let hir::Node::Item(Item {
+                kind: ItemKind::ForeignMod { abi: Abi::RustIntrinsic | Abi::PlatformIntrinsic, .. },
+                ..
+            }) = hir.get(parent)
+        {
+            return true;
+        }
+
+        self.tcx.sess.emit_err(errors::RustcSafeIntrinsic { attr_span: attr.span, span });
+        false
+    }
+
     fn check_rustc_std_internal_symbol(
         &self,
         attr: &Attribute,

compiler/rustc_passes/src/errors.rs

@@ -620,6 +620,15 @@ pub struct RustcAllowConstFnUnstable {
     pub span: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(passes_rustc_safe_intrinsic)]
+pub struct RustcSafeIntrinsic {
+    #[primary_span]
+    pub attr_span: Span,
+    #[label]
+    pub span: Span,
+}
+
 #[derive(Diagnostic)]
 #[diag(passes_rustc_std_internal_symbol)]
 pub struct RustcStdInternalSymbol {

compiler/rustc_query_system/src/query/plumbing.rs

@@ -18,7 +18,7 @@ use rustc_data_structures::sharded::Sharded;
 use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_data_structures::sync::Lock;
 #[cfg(parallel_compiler)]
-use rustc_data_structures::{cold_path, sync};
+use rustc_data_structures::{outline, sync};
 use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed, FatalError};
 use rustc_span::{Span, DUMMY_SP};
 use std::cell::Cell;
@@ -265,7 +265,7 @@ where
     match result {
         Ok(()) => {
             let Some((v, index)) = query.query_cache(qcx).lookup(&key) else {
-                cold_path(|| {
+                outline(|| {
                     // We didn't find the query result in the query cache. Check if it was
                     // poisoned due to a panic instead.
                     let lock = query.query_state(qcx).active.get_shard_by_value(&key).lock();

compiler/rustc_span/src/lib.rs

@@ -33,7 +33,7 @@ extern crate rustc_macros;
 #[macro_use]
 extern crate tracing;
 
-use rustc_data_structures::{cold_path, AtomicRef};
+use rustc_data_structures::{outline, AtomicRef};
 use rustc_macros::HashStable_Generic;
 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
 
@@ -1592,7 +1592,7 @@ impl SourceFile {
             return &lines[..];
         }
 
-        cold_path(|| {
+        outline(|| {
             self.convert_diffs_to_lines_frozen();
             if let Some(SourceFileLines::Lines(lines)) = self.lines.get() {
                 return &lines[..];

src/doc/embedded-book

@@ -1 +1 @@
-Subproject commit 99ad2847b865e96d8ae7b333d3ee96963557e621
+Subproject commit eac173690b8cc99094e1d88bd49dd61127fbd285

src/doc/nomicon

@@ -1 +1 @@
-Subproject commit e3f3af69dce71cd37a785bccb7e58449197d940c
+Subproject commit ddfa4214487686e91b21aa29afb972c08a8f0d5b

src/doc/reference

@@ -1 +1 @@
-Subproject commit ee7c676fd6e287459cb407337652412c990686c0
+Subproject commit 5262e1c3b43a2c489df8f6717683a44c7a2260fd

src/doc/rustc-dev-guide

@@ -1 +1 @@
-Subproject commit 08bb147d51e815b96e8db7ba4cf870f201c11ff8
+Subproject commit a13b7c28ed705891c681ce5417b3d1cdb12cecd1

src/doc/rustdoc/src/unstable-features.md

@@ -375,7 +375,7 @@ library, as an equivalent command-line argument is provided to `rustc` when buil
 This feature allows you to generate an index-page with a given markdown file. A good example of it
 is the [rust documentation index](https://doc.rust-lang.org/nightly/index.html).
 
-With this, you'll have a page which you can custom as much as you want at the top of your crates.
+With this, you'll have a page which you can customize as much as you want at the top of your crates.
 
 Using `index-page` option enables `enable-index-page` option as well.
 

tests/ui/codegen/issue-79865-llvm-miscompile.rs

@@ -0,0 +1,38 @@
+// run-pass
+// only-x86_64
+// compile-flags: -C opt-level=3
+
+// Regression test for issue #79865.
+// The assertion will fail when compiled with Rust 1.56..=1.59
+// due to a LLVM miscompilation.
+
+use std::arch::x86_64::*;
+
+fn main() {
+    if is_x86_feature_detected!("avx") {
+        let res: [f64; 4] = unsafe { std::mem::transmute::<_, _>(first()) };
+        assert_eq!(res, [22.0, 44.0, 66.0, 88.0]);
+    }
+}
+
+#[target_feature(enable = "avx")]
+unsafe fn first() -> __m256d {
+    second()
+}
+
+unsafe fn second() -> __m256d {
+    let v0 = _mm256_setr_pd(1.0, 2.0, 3.0, 4.0);
+    let v1 = _mm256_setr_pd(10.0, 20.0, 30.0, 40.0);
+
+    // needs to be called twice to hit the miscompilation
+    let (add, _) = add_sub(v0, v1);
+    let (add, _) = add_sub(add, add);
+    add
+}
+
+#[inline(never)] // needed to hit the miscompilation
+unsafe fn add_sub(v1: __m256d, v0: __m256d) -> (__m256d, __m256d) {
+    let add = _mm256_add_pd(v0, v1);
+    let sub = _mm256_sub_pd(v0, v1);
+    (add, sub)
+}

tests/ui/error-codes/E0094.rs

@@ -1,4 +1,4 @@
-#![feature(intrinsics)]
+#![feature(intrinsics, rustc_attrs)]
 
 extern "rust-intrinsic" {
     #[rustc_safe_intrinsic]

tests/ui/extern/extern-with-type-bounds.rs

@@ -1,4 +1,4 @@
-#![feature(intrinsics)]
+#![feature(intrinsics, rustc_attrs)]
 
 extern "rust-intrinsic" {
     // Real example from libcore

tests/ui/intrinsics/feature-gate-safe-intrinsic.rs

@@ -0,0 +1,6 @@
+#[rustc_safe_intrinsic]
+//~^ ERROR the `#[rustc_safe_intrinsic]` attribute is used internally to mark intrinsics as safe
+//~| ERROR attribute should be applied to intrinsic functions
+fn safe() {}
+
+fn main() {}

tests/ui/intrinsics/feature-gate-safe-intrinsic.stderr

@@ -0,0 +1,20 @@
+error[E0658]: the `#[rustc_safe_intrinsic]` attribute is used internally to mark intrinsics as safe
+  --> $DIR/feature-gate-safe-intrinsic.rs:1:1
+   |
+LL | #[rustc_safe_intrinsic]
+   | ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add `#![feature(rustc_attrs)]` to the crate attributes to enable
+
+error: attribute should be applied to intrinsic functions
+  --> $DIR/feature-gate-safe-intrinsic.rs:1:1
+   |
+LL | #[rustc_safe_intrinsic]
+   | ^^^^^^^^^^^^^^^^^^^^^^^
+...
+LL | fn safe() {}
+   | ------------ not an intrinsic function
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0658`.

tests/ui/intrinsics/intrinsic-alignment.rs

@@ -1,7 +1,7 @@
 // run-pass
 // ignore-wasm32-bare seems not important to test here
 
-#![feature(intrinsics)]
+#![feature(intrinsics, rustc_attrs)]
 
 mod rusti {
     extern "rust-intrinsic" {

tests/ui/repr/16-bit-repr-c-enum.rs

@@ -5,7 +5,7 @@
 // [avr] compile-flags: --target=avr-unknown-gnu-atmega328 --crate-type=rlib
 // [msp430] needs-llvm-components: msp430
 // [msp430] compile-flags: --target=msp430-none-elf --crate-type=rlib
-#![feature(no_core, lang_items, intrinsics, staged_api)]
+#![feature(no_core, lang_items, intrinsics, staged_api, rustc_attrs)]
 #![no_core]
 #![crate_type = "lib"]
 #![stable(feature = "", since = "")]

tests/ui/structs-enums/rec-align-u32.rs

@@ -3,7 +3,7 @@
 #![allow(unused_unsafe)]
 // Issue #2303
 
-#![feature(intrinsics)]
+#![feature(intrinsics, rustc_attrs)]
 
 use std::mem;
 

tests/ui/structs-enums/rec-align-u64.rs

@@ -5,7 +5,7 @@
 
 // Issue #2303
 
-#![feature(intrinsics)]
+#![feature(intrinsics, rustc_attrs)]
 
 use std::mem;