Auto merge of #165011 - tgross35:std_detect-updates, r=<try>

std: Clean up and improve errors for `is_*_feature_detected` macros


try-job: test-i686-gnu-1

Author: bors

library/std_detect/src/detect/arch/mod.rs

@@ -22,40 +22,40 @@ mod s390x;
 
 cfg_select! {
     any(target_arch = "x86", target_arch = "x86_64") => {
-        #[stable(feature = "simd_x86", since = "1.27.0")]
-        pub use x86::*;
+        pub use x86::__is_feature_detected;
+        pub(crate) use x86::Feature;
     }
     target_arch = "arm" => {
-        #[unstable(feature = "stdarch_arm_feature_detection", issue = "111190")]
-        pub use arm::*;
+        pub use arm::__is_feature_detected;
+        pub(crate) use arm::Feature;
     }
     any(target_arch = "aarch64", target_arch = "arm64ec") => {
-        #[stable(feature = "simd_aarch64", since = "1.60.0")]
-        pub use aarch64::*;
+        pub use aarch64::__is_feature_detected;
+        pub(crate) use aarch64::Feature;
     }
     any(target_arch = "riscv32", target_arch = "riscv64") => {
-        #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")]
-        pub use riscv::*;
+        pub use riscv::__is_feature_detected;
+        pub(crate) use riscv::Feature;
     }
     any(target_arch = "powerpc", target_arch = "powerpc64") => {
-        #[unstable(feature = "stdarch_powerpc_feature_detection", issue = "111191")]
-        pub use powerpc::*;
+        pub use powerpc::__is_feature_detected;
+        pub(crate) use powerpc::Feature;
     }
     target_arch = "mips" => {
-        #[unstable(feature = "stdarch_mips_feature_detection", issue = "111188")]
-        pub use mips::*;
+        pub use mips::__is_feature_detected;
+        pub(crate) use mips::Feature;
     }
     target_arch = "mips64" => {
-        #[unstable(feature = "stdarch_mips_feature_detection", issue = "111188")]
-        pub use mips64::*;
+        pub use mips64::__is_feature_detected;
+        pub(crate) use mips64::Feature;
     }
     any(target_arch = "loongarch32", target_arch = "loongarch64") => {
-        #[stable(feature = "stdarch_loongarch_feature", since = "1.89.0")]
-        pub use loongarch::*;
+        pub use loongarch::__is_feature_detected;
+        pub(crate) use loongarch::Feature;
     }
     target_arch = "s390x" => {
-        #[stable(feature = "stdarch_s390x_feature_detection", since = "1.93.0")]
-        pub use s390x::*;
+        pub use s390x::__is_feature_detected;
+        pub(crate) use s390x::Feature;
     }
     _ => {
         // Unimplemented architecture:
@@ -64,7 +64,6 @@ cfg_select! {
             Null,
         }
         #[doc(hidden)]
-        #[unstable(feature = "stdarch_internal", issue = "none")]
         pub mod __is_feature_detected {}
 
         impl Feature {

library/std_detect/src/detect/macros.rs

@@ -1,3 +1,4 @@
+/// Forward a literal to the relevant `__is_feature_detected` function.
 #[macro_export]
 #[allow_internal_unstable(stdarch_internal)]
 #[unstable(feature = "stdarch_internal", issue = "none")]
@@ -6,6 +7,7 @@ macro_rules! detect_feature {
         $crate::detect_feature!($feature, $feature_lit : $feature_lit)
     };
     ($feature:tt, $feature_lit:tt : $($target_feature_lit:tt),*) => {
+        // Emit `true` if enabled at compile time
         $(cfg!(target_feature = $target_feature_lit) ||)*
             $crate::detect::__is_feature_detected::$feature()
     };
@@ -14,6 +16,7 @@ macro_rules! detect_feature {
     };
 }
 
+/// Verify that all features are known by `cfg!`.
 #[allow(unused_macros, reason = "it's used in the features! macro below")]
 macro_rules! check_cfg_feature {
     ($feature:tt, $feature_lit:tt) => {
@@ -28,31 +31,54 @@ macro_rules! check_cfg_feature {
     };
 }
 
+/// Create the `is_*_feature_detected` macro for an architecture.
+// Make sure any additions to this macro are tested in
+// `tests/ui/std/is_arch_feature_detected.AARCH64.stderr`.
 #[allow(unused)]
 macro_rules! features {
     (
-      @TARGET: $target:ident;
-      @CFG: $cfg:meta;
-      @MACRO_NAME: $macro_name:ident;
-      @MACRO_ATTRS: $(#[$macro_attrs:meta])*
-      $(@BIND_FEATURE_NAME: $bind_feature:tt; $feature_impl:tt; $(#[$deprecate_attr:meta];)?)*
-      $(@NO_RUNTIME_DETECTION: $nort_feature:tt; )*
-      $(@FEATURE: #[$stability_attr:meta] $feature:ident: $feature_lit:tt;
-          $(without cfg check: $feature_cfg_check:tt;)?
-          $(implied by target_features: [$($target_feature_lit:tt),*];)?
-          $(#[$feature_comment:meta])*)*
+        // Target or target family name, for use in diagnostic messages
+        @TARGET: $target:ident;
+        // Cfg for which this macro should be allowed
+        @CFG: $cfg:meta;
+        // Name like `is_*_feature_detected`
+        @MACRO_NAME: $macro_name:ident;
+        // Docs and stability attributes
+        @MACRO_ATTRS: $(#[$macro_attrs:meta])*
+        // Synonyms, with possible deprecation
+        $(@BIND_FEATURE_NAME: $bind_feature:tt; $feature_impl:tt; $(#[$deprecate_attr:meta];)?)*
+        // Features that exist but can't be detected at runtime, so emit an error.
+        $(@NO_RUNTIME_DETECTION: $nort_feature:tt; )*
+        // List of features
+        $(@FEATURE: #[$stability_attr:meta] $feature:ident: $feature_lit:tt;
+            // Skip verifying that the feature is known by `cfg!`, which also skips emitting `true`
+            // if the feature is enabled at compile time.
+            $(without cfg check: $feature_cfg_check:tt;)?
+            // If this feature is always enabled by some other feature, we can avoid the cost of
+            // checking them separately by instead only checking the root features.
+            $(implied by target_features: [$($target_feature_lit:tt),*];)?
+            // Doc comment for the feature.
+            $(#[$feature_comment:meta])*)*
     ) => {
+        // The current arch's version actually does the feature detection.
         #[macro_export]
         $(#[$macro_attrs])*
         #[allow_internal_unstable(stdarch_internal)]
         #[cfg($cfg)]
         #[doc(cfg($cfg))]
         macro_rules! $macro_name {
+            // Emit all known features
             $(
                 ($feature_lit) => {
-                    $crate::detect_feature!($feature, $feature_lit $(, without cfg check: $feature_cfg_check)? $(: $($target_feature_lit),*)?)
+                    $crate::detect_feature!(
+                        $feature,
+                        $feature_lit
+                        $(, without cfg check: $feature_cfg_check)?
+                        $(: $($target_feature_lit),*)?
+                    )
                 };
             )*
+            // Emit all aliases, with a deprecation notice if applicable
             $(
                 ($bind_feature) => {
                     {
@@ -64,6 +90,7 @@ macro_rules! features {
                     }
                 };
             )*
+            // Emit an error for features that can't be detected at runtime
             $(
                 ($nort_feature) => {
                     compile_error!(
@@ -74,40 +101,41 @@ macro_rules! features {
                     )
                 };
             )*
+            // Allow a trailing comma
             ($t:tt,) => {
-                    $crate::$macro_name!($t)
+                $crate::$macro_name!($t)
             };
+            // Fallback, error for unknown target features
             ($t:tt) => {
                 compile_error!(
-                    concat!(
-                        concat!("unknown ", stringify!($target)),
-                        concat!(" target feature: ", $t)
-                    )
+                    concat!("unknown ", stringify!($target), " target feature: ", $t)
                 )
             };
         }
 
+        // All other arches still validate the features, but also
         $(#[$macro_attrs])*
         #[macro_export]
         #[cfg(not($cfg))]
         #[doc(cfg($cfg))]
         macro_rules! $macro_name {
+            // All known features get an error
             $(
                 ($feature_lit) => {
                     compile_error!(
                         concat!(
-                            r#"This macro cannot be used on the current target.
-                            You can prevent it from being used in other architectures by
-                            guarding it behind a cfg("#,
-                            stringify!($cfg),
-                            ")."
+                            "This macro cannot be used on the current target. You can prevent\n\
+                            it from being used in other architectures by guarding it behind\n\
+                            a `cfg(", stringify!($cfg), ")`."
                         )
                     )
                 };
             )*
+            // Forward deprecated features
             $(
                 ($bind_feature) => { $crate::$macro_name!($feature_impl) };
             )*
+            // Emit an error for features that can't be detected at runtime
             $(
                 ($nort_feature) => {
                     compile_error!(
@@ -118,15 +146,14 @@ macro_rules! features {
                     )
                 };
             )*
+            // Allow a trailing comma
             ($t:tt,) => {
                     $crate::$macro_name!($t);
             };
+            // Fallback, error for unknown target features
             ($t:tt) => {
                 compile_error!(
-                    concat!(
-                        concat!("unknown ", stringify!($target)),
-                        concat!(" target feature: ", $t)
-                    )
+                    concat!("unknown ", stringify!($target), " target feature: ", $t)
                 )
             };
         }
@@ -135,7 +162,12 @@ macro_rules! features {
         #[deny(unfulfilled_lint_expectations)]
         const _: () = {
             $(
-                check_cfg_feature!($feature, $feature_lit $(, without cfg check: $feature_cfg_check)? $(: $($target_feature_lit),*)?);
+                check_cfg_feature!(
+                    $feature,
+                    $feature_lit
+                    $(, without cfg check: $feature_cfg_check)?
+                    $(: $($target_feature_lit),*)?)
+                ;
             )*
         };
 
@@ -185,7 +217,6 @@ macro_rules! features {
         /// to change.
         #[doc(hidden)]
         #[cfg($cfg)]
-        #[unstable(feature = "stdarch_internal", issue = "none")]
         pub mod __is_feature_detected {
             $(
 

library/std_detect/src/detect/mod.rs

@@ -24,7 +24,6 @@ mod arch;
 
 // This module needs to be public because the `is_{arch}_feature_detected!`
 // macros expand calls to items within it in user crates.
-#[doc(hidden)]
 #[unstable(feature = "stdarch_internal", issue = "none")]
 pub use self::arch::__is_feature_detected;
 pub(crate) use self::arch::Feature;

tests/ui/std/is_arch_feature_detected.AARCH64.stderr

@@ -0,0 +1,78 @@
+error: unknown x86 target feature: not-a-feature
+  --> $DIR/is_arch_feature_detected.rs:22:13
+   |
+LL |     let _ = arch::is_x86_feature_detected!("not-a-feature");
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the macro `arch::is_x86_feature_detected` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: unknown aarch64 target feature: not-a-feature
+  --> $DIR/is_arch_feature_detected.rs:24:13
+   |
+LL |     let _ = arch::is_aarch64_feature_detected!("not-a-feature");
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the macro `arch::is_aarch64_feature_detected` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: This macro cannot be used on the current target. You can prevent
+       it from being used in other architectures by guarding it behind
+       a `cfg(any(target_arch = "x86", target_arch = "x86_64"))`.
+  --> $DIR/is_arch_feature_detected.rs:29:13
+   |
+LL |     let _ = arch::is_x86_feature_detected!("sse");
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the macro `arch::is_x86_feature_detected` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: This macro cannot be used on the current target. You can prevent
+       it from being used in other architectures by guarding it behind
+       a `cfg(any(target_arch = "x86", target_arch = "x86_64"))`.
+  --> $DIR/is_arch_feature_detected.rs:36:13
+   |
+LL |     let _ = arch::is_x86_feature_detected!("avx512gfni");
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the macro `$crate::is_x86_feature_detected` which comes from the expansion of the macro `arch::is_x86_feature_detected` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: "ras" feature cannot be detected at run-time
+  --> $DIR/is_arch_feature_detected.rs:41:13
+   |
+LL |     let _ = arch::is_aarch64_feature_detected!("ras");
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the macro `arch::is_aarch64_feature_detected` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0658]: use of unstable library feature `stdarch_mips_feature_detection`
+  --> $DIR/is_arch_feature_detected.rs:45:13
+   |
+LL |     let _ = arch::is_mips_feature_detected!("msa");
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #111188 <https://github.com/rust-lang/rust/issues/111188> for more information
+   = help: add `#![feature(stdarch_mips_feature_detection)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error: This macro cannot be used on the current target. You can prevent
+       it from being used in other architectures by guarding it behind
+       a `cfg(target_arch = "mips")`.
+  --> $DIR/is_arch_feature_detected.rs:45:13
+   |
+LL |     let _ = arch::is_mips_feature_detected!("msa");
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the macro `arch::is_mips_feature_detected` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0658]: use of unstable library feature `stdarch_aarch64_feature_detection`
+  --> $DIR/is_arch_feature_detected.rs:52:13
+   |
+LL |     let _ = arch::is_aarch64_feature_detected!("wfxt");
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #127764 <https://github.com/rust-lang/rust/issues/127764> for more information
+   = help: add `#![feature(stdarch_aarch64_feature_detection)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+   = note: this error originates in the macro `$crate::detect_feature` which comes from the expansion of the macro `arch::is_aarch64_feature_detected` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 8 previous errors
+
+For more information about this error, try `rustc --explain E0658`.

tests/ui/std/is_arch_feature_detected.NEITHER.stderr

@@ -0,0 +1,56 @@
+error: unknown x86 target feature: not-a-feature
+  --> $DIR/is_arch_feature_detected.rs:22:13
+   |
+LL |     let _ = arch::is_x86_feature_detected!("not-a-feature");
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the macro `arch::is_x86_feature_detected` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: unknown aarch64 target feature: not-a-feature
+  --> $DIR/is_arch_feature_detected.rs:24:13
+   |
+LL |     let _ = arch::is_aarch64_feature_detected!("not-a-feature");
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the macro `arch::is_aarch64_feature_detected` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: "ras" feature cannot be detected at run-time
+  --> $DIR/is_arch_feature_detected.rs:41:13
+   |
+LL |     let _ = arch::is_aarch64_feature_detected!("ras");
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the macro `arch::is_aarch64_feature_detected` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0658]: use of unstable library feature `stdarch_mips_feature_detection`
+  --> $DIR/is_arch_feature_detected.rs:45:13
+   |
+LL |     let _ = arch::is_mips_feature_detected!("msa");
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #111188 <https://github.com/rust-lang/rust/issues/111188> for more information
+   = help: add `#![feature(stdarch_mips_feature_detection)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error: This macro cannot be used on the current target. You can prevent
+       it from being used in other architectures by guarding it behind
+       a `cfg(target_arch = "mips")`.
+  --> $DIR/is_arch_feature_detected.rs:45:13
+   |
+LL |     let _ = arch::is_mips_feature_detected!("msa");
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this error originates in the macro `arch::is_mips_feature_detected` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+warning: use of deprecated macro `deprecated_feature`: the `avx512gfni` feature has been renamed to `gfni`
+  --> $DIR/is_arch_feature_detected.rs:36:13
+   |
+LL |     let _ = arch::is_x86_feature_detected!("avx512gfni");
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(deprecated)]` on by default
+   = note: this warning originates in the macro `arch::is_x86_feature_detected` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 5 previous errors; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0658`.