Introduce #[cfg(target_feature = "cg_clif")]

Author: bjorn3

patches/0016-Disable-cpuid-intrinsic.patch

@@ -11,12 +11,14 @@ diff --git a/src/stdarch/crates/core_arch/src/x86/cpuid.rs b/src/stdarch/crates/
 index f313c42..ff952bc 100644
 --- a/src/stdarch/crates/core_arch/src/x86/cpuid.rs
 +++ b/src/stdarch/crates/core_arch/src/x86/cpuid.rs
-@@ -84,6 +84,9 @@ pub unsafe fn __cpuid(leaf: u32) -> CpuidResult {
+@@ -84,6 +84,11 @@ pub unsafe fn __cpuid(leaf: u32) -> CpuidResult {
  /// Does the host support the `cpuid` instruction?
  #[inline]
  pub fn has_cpuid() -> bool {
 +    // __cpuid intrinsic is not yet implemented
-+    return false;
++    #[cfg(target_feature = "cg_clif")] {
++        return false;
++    }
 +
      #[cfg(target_env = "sgx")]
      {

src/lib.rs

@@ -188,18 +188,24 @@ impl CodegenBackend for CraneliftCodegenBackend {
                 // rustdoc needs to be able to document functions that use all the features, so
                 // whitelist them all
                 target_features_whitelist::all_known_features()
+                    .chain(Some(("cg_clif", None)))
                     .map(|(a, b)| (a.to_string(), b))
                     .collect()
             } else {
                 target_features_whitelist::target_feature_whitelist(tcx.sess)
                     .iter()
+                    .chain(&Some(("cg_clif", None)))
                     .map(|&(a, b)| (a.to_string(), b))
                     .collect()
             }
         };
     }
     fn provide_extern(&self, _providers: &mut Providers<'_>) {}
 
+    fn target_features(&self, _sess: &Session) -> Vec<rustc_span::Symbol> {
+        vec![rustc_span::Symbol::intern("cg_clif")]
+    }
+
     fn codegen_crate<'tcx>(
         &self,
         tcx: TyCtxt<'tcx>,