Only retain no_mangle static symbols across LTO

Author: arcnmx

src/librustc/metadata/csearch.rs

@@ -344,9 +344,9 @@ pub fn is_const_fn(cstore: &cstore::CStore, did: DefId) -> bool {
     decoder::is_const_fn(&*cdata, did.index)
 }
 
-pub fn is_static(cstore: &cstore::CStore, did: DefId) -> bool {
+pub fn is_extern_static(cstore: &cstore::CStore, did: DefId) -> bool {
     let cdata = cstore.get_crate_data(did.krate);
-    decoder::is_static(&*cdata, did.index)
+    decoder::is_extern_static(&*cdata, did.index)
 }
 
 pub fn is_impl(cstore: &cstore::CStore, did: DefId) -> bool {

src/librustc/metadata/decoder.rs

@@ -1425,10 +1425,13 @@ pub fn is_const_fn(cdata: Cmd, id: DefIndex) -> bool {
     }
 }
 
-pub fn is_static(cdata: Cmd, id: DefIndex) -> bool {
+pub fn is_extern_static(cdata: Cmd, id: DefIndex) -> bool {
     let item_doc = cdata.lookup_item(id);
     match item_family(item_doc) {
-        ImmStatic | MutStatic => true,
+        ImmStatic | MutStatic => {
+            let attrs = get_attributes(item_doc);
+            attr::contains_name(&attrs, "no_mangle")
+        },
         _ => false,
     }
 }

src/librustc_trans/trans/base.rs

@@ -2876,7 +2876,7 @@ pub fn trans_crate<'tcx>(tcx: &ty::ctxt<'tcx>,
             let syms = csearch::get_reachable_ids(&sess.cstore, cnum);
             reachable_symbols.extend(syms.into_iter().filter(|did| {
                 csearch::is_extern_fn(&sess.cstore, *did, shared_ccx.tcx()) ||
-                csearch::is_static(&sess.cstore, *did)
+                csearch::is_extern_static(&sess.cstore, *did)
             }).map(|did| {
                 csearch::get_symbol(&sess.cstore, did)
             }));