Merge ref '82310651b93a' from rust-lang/rust

Pull recent changes from https://github.com/rust-lang/rust via Josh.

Upstream ref: 82310651b93a594a3fd69015e1562186a080d94c
Filtered ref: e13c0be8f13737c64082b89ce834546079767ac4

This merge was created using https://github.com/rust-lang/josh-sync.

1 files changed, 204 insertions, 0 deletions

diff --git a/library/stdarch/crates/std_detect/src/detect/macros.rs b/library/stdarch/crates/std_detect/src/detect/macros.rs
new file mode 100644
index 00000000000..a2994fb7daa
--- /dev/null
+++ b/library/stdarch/crates/std_detect/src/detect/macros.rs
@@ -0,0 +1,204 @@
+#[macro_export]
+#[allow_internal_unstable(stdarch_internal)]
+#[unstable(feature = "stdarch_internal", issue = "none")]
+macro_rules! detect_feature {
+    ($feature:tt, $feature_lit:tt) => {
+        $crate::detect_feature!($feature, $feature_lit : $feature_lit)
+    };
+    ($feature:tt, $feature_lit:tt : $($target_feature_lit:tt),*) => {
+        $(cfg!(target_feature = $target_feature_lit) ||)*
+            $crate::detect::__is_feature_detected::$feature()
+    };
+    ($feature:tt, $feature_lit:tt, without cfg check: true) => {
+        $crate::detect::__is_feature_detected::$feature()
+    };
+}
+
+#[allow(unused_macros, reason = "it's used in the features! macro below")]
+macro_rules! check_cfg_feature {
+    ($feature:tt, $feature_lit:tt) => {
+        check_cfg_feature!($feature, $feature_lit : $feature_lit)
+    };
+    ($feature:tt, $feature_lit:tt : $($target_feature_lit:tt),*) => {
+        $(cfg!(target_feature = $target_feature_lit);)*
+    };
+    ($feature:tt, $feature_lit:tt, without cfg check: $feature_cfg_check:literal) => {
+        #[allow(unexpected_cfgs, reason = $feature_lit)]
+        { cfg!(target_feature = $feature_lit) }
+    };
+}
+
+#[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])*)*
+    ) => {
+        #[macro_export]
+        $(#[$macro_attrs])*
+        #[allow_internal_unstable(stdarch_internal)]
+        #[cfg($cfg)]
+        #[doc(cfg($cfg))]
+        macro_rules! $macro_name {
+            $(
+                ($feature_lit) => {
+                    $crate::detect_feature!($feature, $feature_lit $(, without cfg check: $feature_cfg_check)? $(: $($target_feature_lit),*)?)
+                };
+            )*
+            $(
+                ($bind_feature) => {
+                    {
+                        $(
+                            #[$deprecate_attr] macro_rules! deprecated_feature { {} => {}; }
+                            deprecated_feature! {};
+                        )?
+                        $crate::$macro_name!($feature_impl)
+                    }
+                };
+            )*
+            $(
+                ($nort_feature) => {
+                    compile_error!(
+                        concat!(
+                            stringify!($nort_feature),
+                            " feature cannot be detected at run-time"
+                        )
+                    )
+                };
+            )*
+            ($t:tt,) => {
+                    $crate::$macro_name!($t);
+            };
+            ($t:tt) => {
+                compile_error!(
+                    concat!(
+                        concat!("unknown ", stringify!($target)),
+                        concat!(" target feature: ", $t)
+                    )
+                )
+            };
+        }
+
+        $(#[$macro_attrs])*
+        #[macro_export]
+        #[cfg(not($cfg))]
+        #[doc(cfg($cfg))]
+        macro_rules! $macro_name {
+            $(
+                ($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),
+                            ")."
+                        )
+                    )
+                };
+            )*
+            $(
+                ($bind_feature) => { $crate::$macro_name!($feature_impl) };
+            )*
+            $(
+                ($nort_feature) => {
+                    compile_error!(
+                        concat!(
+                            stringify!($nort_feature),
+                            " feature cannot be detected at run-time"
+                        )
+                    )
+                };
+            )*
+            ($t:tt,) => {
+                    $crate::$macro_name!($t);
+            };
+            ($t:tt) => {
+                compile_error!(
+                    concat!(
+                        concat!("unknown ", stringify!($target)),
+                        concat!(" target feature: ", $t)
+                    )
+                )
+            };
+        }
+
+        #[test]
+        #[deny(unexpected_cfgs)]
+        #[deny(unfulfilled_lint_expectations)]
+        fn unexpected_cfgs() {
+            $(
+                check_cfg_feature!($feature, $feature_lit $(, without cfg check: $feature_cfg_check)? $(: $($target_feature_lit),*)?);
+            )*
+        }
+
+        /// Each variant denotes a position in a bitset for a particular feature.
+        ///
+        /// PLEASE: do not use this, it is an implementation detail subject
+        /// to change.
+        #[doc(hidden)]
+        #[allow(non_camel_case_types)]
+        #[derive(Copy, Clone)]
+        #[repr(u8)]
+        #[unstable(feature = "stdarch_internal", issue = "none")]
+        #[cfg($cfg)]
+        pub(crate) enum Feature {
+            $(
+                $(#[$feature_comment])*
+                $feature,
+            )*
+
+            // Do not add variants after last:
+            _last
+        }
+
+        #[cfg($cfg)]
+        impl Feature {
+            pub(crate) fn to_str(self) -> &'static str {
+                match self {
+                    $(Feature::$feature => $feature_lit,)*
+                    Feature::_last => unreachable!(),
+                }
+            }
+
+            #[cfg(feature = "std_detect_env_override")]
+            pub(crate) fn from_str(s: &str) -> Result<Feature, ()> {
+                match s {
+                    $($feature_lit => Ok(Feature::$feature),)*
+                    _ => Err(())
+                }
+            }
+        }
+
+        /// Each function performs run-time feature detection for a single
+        /// feature. This allow us to use stability attributes on a per feature
+        /// basis.
+        ///
+        /// PLEASE: do not use this, it is an implementation detail subject
+        /// to change.
+        #[doc(hidden)]
+        #[cfg($cfg)]
+        #[unstable(feature = "stdarch_internal", issue = "none")]
+        pub mod __is_feature_detected {
+            $(
+
+                /// PLEASE: do not use this, it is an implementation detail
+                /// subject to change.
+                #[inline]
+                #[doc(hidden)]
+                #[$stability_attr]
+                pub fn $feature() -> bool {
+                    $crate::detect::check_for($crate::detect::Feature::$feature)
+                }
+            )*
+        }
+    };
+}