Add target_cfg_f macro

calebzulawski · Dec 10, 2022 · ac5fcb8 · ac5fcb8
1 parent 3c682fc
commit ac5fcb8
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Showing 4 changed files with 47 additions and 2 deletions.
diff --git a/multiversion-macros/src/dispatcher.rs b/multiversion-macros/src/dispatcher.rs
@@ -104,13 +104,18 @@ impl Dispatcher {
                             { [$cfg:meta, $attr:meta] $($attached:tt)* } => { #[multiversion::target::target_cfg_attr_impl(#features, $cfg, $attr)] $($attached)* };
                         }
 
+                        macro_rules! target_cfg_f {
+                            { $cfg:meta } => { multiversion::target::target_cfg_f_impl!(#features, $cfg) };
+                        }
+
                         macro_rules! match_target {
                             { $($arms:tt)* } => { multiversion::target::match_target_impl!{ #features $($arms)* } }
                         }
 
                         pub(crate) use inherit_target;
                         pub(crate) use target_cfg;
                         pub(crate) use target_cfg_attr;
+                        pub(crate) use target_cfg_f;
                         pub(crate) use match_target;
                     }
                     #block

diff --git a/multiversion-macros/src/lib.rs b/multiversion-macros/src/lib.rs
@@ -87,6 +87,15 @@ pub fn target_cfg_attr(
     .into()
 }
 
+#[proc_macro]
+pub fn target_cfg_f(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    let input = TokenStream::from(input);
+    quote! {
+        __multiversion::target_cfg_f!{ #input }
+    }
+    .into()
+}
+
 #[proc_macro_attribute]
 pub fn target_cfg_impl(
     attr: proc_macro::TokenStream,
@@ -120,6 +129,17 @@ pub fn target_cfg_attr_impl(
     .into()
 }
 
+#[proc_macro]
+pub fn target_cfg_f_impl(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    let meta = parse_macro_input!(input with Punctuated::parse_terminated);
+
+    let meta = cfg::transform(meta);
+    quote! {
+        cfg!(#meta)
+    }
+    .into()
+}
+
 #[proc_macro]
 pub fn match_target(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
     let input = TokenStream::from(input);

diff --git a/multiversion/src/lib.rs b/multiversion/src/lib.rs
@@ -218,8 +218,15 @@ pub mod target {
     /// ```
     pub use multiversion_macros::match_target;
 
+    /// Equivalent to `cfg!`, but considers `target_feature`s detected at runtime.
+    ///
+    /// This macro only works in a function marked with [`multiversion`].
+    pub use multiversion_macros::target_cfg_f;
+
     #[doc(hidden)]
-    pub use multiversion_macros::{match_target_impl, target_cfg_attr_impl, target_cfg_impl};
+    pub use multiversion_macros::{
+        match_target_impl, target_cfg_attr_impl, target_cfg_f_impl, target_cfg_impl,
+    };
 
     #[doc(no_inline)]
     pub use target_features::Target;

diff --git a/multiversion/tests/cfg.rs b/multiversion/tests/cfg.rs
@@ -1,6 +1,6 @@
 use multiversion::{
     multiversion,
-    target::{match_target, selected_target, target_cfg, target_cfg_attr},
+    target::{match_target, selected_target, target_cfg, target_cfg_attr, target_cfg_f},
 };
 
 #[test]
@@ -49,6 +49,19 @@ fn cfg_attr() {
     foo();
 }
 
+#[test]
+fn cfg_f() {
+    #[multiversion(targets = "simd")]
+    fn foo() {
+        let cfg_avx = target_cfg_f!(all(target_arch = "x86_64", target_feature = "avx"));
+        let has_avx =
+            std::env::consts::ARCH == "x86_64" && selected_target!().supports_feature_str("avx");
+        assert_eq!(cfg_avx, has_avx);
+    }
+
+    foo();
+}
+
 #[test]
 fn match_target() {
     #[multiversion(targets = "simd")]