Add 'compiler/rustc_codegen_cranelift/' from commit '793d26047f'

git-subtree-dir: compiler/rustc_codegen_cranelift
git-subtree-mainline: cf798c1ec6
git-subtree-split: 793d26047f

compiler/rustc_codegen_cranelift/src/linkage.rs

@@ -0,0 +1,35 @@
+use rustc_middle::mir::mono::{Linkage as RLinkage, MonoItem, Visibility};
+
+use crate::prelude::*;
+
+pub(crate) fn get_clif_linkage(
+    mono_item: MonoItem<'_>,
+    linkage: RLinkage,
+    visibility: Visibility,
+) -> Linkage {
+    match (linkage, visibility) {
+        (RLinkage::External, Visibility::Default) => Linkage::Export,
+        (RLinkage::Internal, Visibility::Default) => Linkage::Local,
+        (RLinkage::External, Visibility::Hidden) => Linkage::Hidden,
+        _ => panic!("{:?} = {:?} {:?}", mono_item, linkage, visibility),
+    }
+}
+
+pub(crate) fn get_static_linkage(tcx: TyCtxt<'_>, def_id: DefId) -> Linkage {
+    let fn_attrs = tcx.codegen_fn_attrs(def_id);
+
+    if let Some(linkage) = fn_attrs.linkage {
+        match linkage {
+            RLinkage::External => Linkage::Export,
+            RLinkage::Internal => Linkage::Local,
+            RLinkage::ExternalWeak | RLinkage::WeakAny => Linkage::Preemptible,
+            _ => panic!("{:?}", linkage),
+        }
+    } else {
+        if tcx.is_reachable_non_generic(def_id) {
+            Linkage::Export
+        } else {
+            Linkage::Hidden
+        }
+    }
+}