Auto merge of #91728 - Amanieu:stable_asm, r=joshtriplett

Stabilize asm! and global_asm!

Tracking issue: #72016

It's been almost 2 years since the original [RFC](rust-lang/rfcs#2850) was posted and we're finally ready to stabilize this feature!

The main changes in this PR are:
- Removing `asm!` and `global_asm!` from the prelude as per the decision in #87228.
- Stabilizing the `asm` and `global_asm` features.
- Removing the unstable book pages for `asm` and `global_asm`. The contents are moved to the [reference](rust-lang/reference#1105) and [rust by example](rust-lang/rust-by-example#1483).
  - All links to these pages have been removed to satisfy the link checker. In a later PR these will be replaced with links to the reference or rust by example.
- Removing the automatic suggestion for using `llvm_asm!` instead of `asm!` if you're still using the old syntax, since it doesn't work anymore with `asm!` no longer being in the prelude. This only affects code that predates the old LLVM-style `asm!` being renamed to `llvm_asm!`.
- Updating `stdarch` and `compiler-builtins`.
- Updating all the tests.

r? `@joshtriplett`

Author: bors

Cargo.lock

@@ -680,9 +680,9 @@ dependencies = [
 
 [[package]]
 name = "compiler_builtins"
-version = "0.1.55"
+version = "0.1.65"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c9ac60765140c97aaf531dae151a287646b0805ec725805da9e2a3ee31cd501c"
+checksum = "ed37ea958309f2451e1cea7fd2b37aa56b1894c9a9fbdbbe6a194f7b78f0362d"
 dependencies = [
  "cc",
  "rustc-std-workspace-core",

compiler/rustc_builtin_macros/src/asm.rs

@@ -42,19 +42,6 @@ fn parse_args<'a>(
             ecx.struct_span_err(sp, "the legacy LLVM-style asm! syntax is no longer supported");
         err.note("consider migrating to the new asm! syntax specified in RFC 2873");
         err.note("alternatively, switch to llvm_asm! to keep your code working as it is");
-
-        // Find the span of the "asm!" so that we can offer an automatic suggestion
-        let asm_span = sp.from_inner(InnerSpan::new(0, 4));
-        if let Ok(s) = ecx.source_map().span_to_snippet(asm_span) {
-            if s == "asm!" {
-                err.span_suggestion(
-                    asm_span,
-                    "replace with",
-                    "llvm_asm!".into(),
-                    Applicability::MachineApplicable,
-                );
-            }
-        }
         return Err(err);
     }
 

compiler/rustc_codegen_cranelift/src/inline_asm.rs

@@ -1,4 +1,4 @@
-//! Codegen of [`asm!`] invocations.
+//! Codegen of `asm!` invocations.
 
 use crate::prelude::*;
 

compiler/rustc_codegen_gcc/tests/run/asm.rs

@@ -3,8 +3,6 @@
 // Run-time:
 //   status: 0
 
-#![feature(asm, global_asm)]
-
 global_asm!("
     .global add_asm
 add_asm:

compiler/rustc_hir/src/def.rs

@@ -113,7 +113,7 @@ pub enum DefKind {
     Field,
     /// Lifetime parameter: the `'a` in `struct Foo<'a> { ... }`
     LifetimeParam,
-    /// A use of [`global_asm!`].
+    /// A use of `global_asm!`.
     GlobalAsm,
     Impl,
     Closure,

compiler/rustc_lint/src/builtin.rs

@@ -3147,7 +3147,8 @@ declare_lint! {
     /// ### Example
     ///
     /// ```rust,compile_fail
-    /// #![feature(asm)]
+    /// use std::arch::asm;
+    ///
     /// fn main() {
     ///     unsafe {
     ///         asm!("foo: bar");
@@ -3164,10 +3165,7 @@ declare_lint! {
     /// of this, GNU assembler [local labels] *must* be used instead of labels
     /// with a name. Using named labels might cause assembler or linker errors.
     ///
-    /// See the [unstable book] for more details.
-    ///
     /// [local labels]: https://sourceware.org/binutils/docs/as/Symbol-Names.html#Local-Labels
-    /// [unstable book]: https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels
     pub NAMED_ASM_LABELS,
     Deny,
     "named labels in inline assembly",

compiler/rustc_lint/src/context.rs

@@ -772,7 +772,6 @@ pub trait LintContext: Sized {
                 }
                 BuiltinLintDiagnostics::NamedAsmLabel(help) => {
                     db.help(&help);
-                    db.note("see the asm section of the unstable book <https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels> for more information");
                 }
             }
             // Rewrap `db`, and pass control to the user.

compiler/rustc_lint_defs/src/builtin.rs

@@ -2419,8 +2419,9 @@ declare_lint! {
     ///
     /// ### Example
     ///
-    /// ```rust,ignore (fails on system llvm)
-    /// #![feature(asm)]
+    /// ```rust,ignore (fails on non-x86_64)
+    /// #[cfg(target_arch="x86_64")]
+    /// use std::arch::asm;
     ///
     /// fn main() {
     ///     #[cfg(target_arch="x86_64")]
@@ -2430,19 +2431,7 @@ declare_lint! {
     /// }
     /// ```
     ///
-    /// This will produce:
-    ///
-    /// ```text
-    /// warning: formatting may not be suitable for sub-register argument
-    ///  --> src/main.rs:6:19
-    ///   |
-    /// 6 |         asm!("mov {0}, {0}", in(reg) 0i16);
-    ///   |                   ^^^  ^^^           ---- for this argument
-    ///   |
-    ///   = note: `#[warn(asm_sub_register)]` on by default
-    ///   = help: use the `x` modifier to have the register formatted as `ax`
-    ///   = help: or use the `r` modifier to keep the default formatting of `rax`
-    /// ```
+    /// {{produces}}
     ///
     /// ### Explanation
     ///
@@ -2455,10 +2444,6 @@ declare_lint! {
     /// register size, to alert you of possibly using the incorrect width. To
     /// fix this, add the suggested modifier to the template, or cast the
     /// value to the correct size.
-    ///
-    /// See [register template modifiers] for more details.
-    ///
-    /// [register template modifiers]: https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#register-template-modifiers
     pub ASM_SUB_REGISTER,
     Warn,
     "using only a subset of a register for inline asm inputs",
@@ -2470,34 +2455,22 @@ declare_lint! {
     ///
     /// ### Example
     ///
-    /// ```rust,ignore (fails on system llvm)
-    /// #![feature(asm)]
+    /// ```rust,ignore (fails on non-x86_64)
+    /// #[cfg(target_arch="x86_64")]
+    /// use std::arch::asm;
     ///
     /// fn main() {
     ///     #[cfg(target_arch="x86_64")]
     ///     unsafe {
     ///         asm!(
     ///             ".att_syntax",
-    ///             "movl {0}, {0}", in(reg) 0usize
+    ///             "movq %{0}, %{0}", in(reg) 0usize
     ///         );
     ///     }
     /// }
     /// ```
     ///
-    /// This will produce:
-    ///
-    /// ```text
-    ///  warning: avoid using `.att_syntax`, prefer using `options(att_syntax)` instead
-    ///  --> test.rs:7:14
-    ///   |
-    /// 7 |             ".att_syntax",
-    ///   |              ^^^^^^^^^^^
-    /// 8 |             "movq {0}, {0}", out(reg) _,
-    /// 9 |         );
-    ///   |         - help: add option: `, options(att_syntax)`
-    ///   |
-    ///   = note: `#[warn(bad_asm_style)]` on by default
-    /// ```
+    /// {{produces}}
     ///
     /// ### Explanation
     ///
@@ -2739,7 +2712,8 @@ declare_lint! {
     ///
     /// ```rust
     /// #![feature(naked_functions)]
-    /// #![feature(asm)]
+    ///
+    /// use std::arch::asm;
     ///
     /// #[naked]
     /// pub fn default_abi() -> u32 {

library/core/src/lib.rs

@@ -153,7 +153,6 @@
 #![feature(abi_unadjusted)]
 #![feature(allow_internal_unsafe)]
 #![feature(allow_internal_unstable)]
-#![feature(asm)]
 #![feature(associated_type_bounds)]
 #![feature(auto_traits)]
 #![feature(cfg_target_has_atomic)]
@@ -373,26 +372,14 @@ pub mod arch {
     pub use crate::core_arch::arch::*;
 
     /// Inline assembly.
-    ///
-    /// Read the [unstable book] for the usage.
-    ///
-    /// [unstable book]: ../../unstable-book/library-features/asm.html
-    #[unstable(
-        feature = "asm",
-        issue = "72016",
-        reason = "inline assembly is not stable enough for use and is subject to change"
-    )]
+    #[stable(feature = "asm", since = "1.59.0")]
     #[rustc_builtin_macro]
     pub macro asm("assembly template", $(operands,)* $(options($(option),*))?) {
         /* compiler built-in */
     }
 
     /// Module-level inline assembly.
-    #[unstable(
-        feature = "global_asm",
-        issue = "35119",
-        reason = "`global_asm!` is not stable enough for use and is subject to change"
-    )]
+    #[stable(feature = "global_asm", since = "1.59.0")]
     #[rustc_builtin_macro]
     pub macro global_asm("assembly template", $(operands,)* $(options($(option),*))?) {
         /* compiler built-in */

library/core/src/num/dec2flt/fpu.rs

@@ -10,6 +10,7 @@ pub use fpu_precision::set_precision;
 // computations are performed in the desired precision.
 #[cfg(all(target_arch = "x86", not(target_feature = "sse2")))]
 mod fpu_precision {
+    use core::arch::asm;
     use core::mem::size_of;
 
     /// A structure used to preserve the original value of the FPU control word, so that it can be