From b61ee5180c3e4cd5b5112995ba2d66b6ab6831f3 Mon Sep 17 00:00:00 2001
From: Michael Woerister <michaelwoerister@posteo>
Date: Fri, 27 Oct 2017 14:30:34 +0200
Subject: [PATCH] Fix translation item collection for inline and const fns.

---
 src/librustc_trans_utils/collector.rs | 30 ++++++++++++++++++++-------
 src/librustc_trans_utils/lib.rs       |  4 ++--
 2 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/src/librustc_trans_utils/collector.rs b/src/librustc_trans_utils/collector.rs
index fd003fc0979..918c97774bc 100644
--- a/src/librustc_trans_utils/collector.rs
+++ b/src/librustc_trans_utils/collector.rs
@@ -324,9 +324,14 @@ fn collect_roots<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     let mut roots = Vec::new();
 
     {
+        let entry_fn = tcx.sess.entry_fn.borrow().map(|(node_id, _)| {
+            tcx.hir.local_def_id(node_id)
+        });
+
         let mut visitor = RootCollector {
             tcx,
             mode,
+            entry_fn,
             output: &mut roots,
         };
 
@@ -875,6 +880,7 @@ struct RootCollector<'b, 'a: 'b, 'tcx: 'a + 'b> {
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     mode: TransItemCollectionMode,
     output: &'b mut Vec<TransItem<'tcx>>,
+    entry_fn: Option<DefId>,
 }
 
 impl<'b, 'a, 'v> ItemLikeVisitor<'v> for RootCollector<'b, 'a, 'v> {
@@ -932,10 +938,7 @@ impl<'b, 'a, 'v> ItemLikeVisitor<'v> for RootCollector<'b, 'a, 'v> {
                 let tcx = self.tcx;
                 let def_id = tcx.hir.local_def_id(item.id);
 
-                if (self.mode == TransItemCollectionMode::Eager ||
-                    !tcx.is_const_fn(def_id) || tcx.is_exported_symbol(def_id)) &&
-                   !item_has_type_parameters(tcx, def_id) {
-
+                if self.is_root(def_id) {
                     debug!("RootCollector: ItemFn({})",
                            def_id_to_string(tcx, def_id));
 
@@ -957,10 +960,7 @@ impl<'b, 'a, 'v> ItemLikeVisitor<'v> for RootCollector<'b, 'a, 'v> {
                 let tcx = self.tcx;
                 let def_id = tcx.hir.local_def_id(ii.id);
 
-                if (self.mode == TransItemCollectionMode::Eager ||
-                    !tcx.is_const_fn(def_id) ||
-                    tcx.is_exported_symbol(def_id)) &&
-                   !item_has_type_parameters(tcx, def_id) {
+                if self.is_root(def_id) {
                     debug!("RootCollector: MethodImplItem({})",
                            def_id_to_string(tcx, def_id));
 
@@ -973,6 +973,20 @@ impl<'b, 'a, 'v> ItemLikeVisitor<'v> for RootCollector<'b, 'a, 'v> {
     }
 }
 
+impl<'b, 'a, 'v> RootCollector<'b, 'a, 'v> {
+    fn is_root(&self, def_id: DefId) -> bool {
+        !item_has_type_parameters(self.tcx, def_id) && match self.mode {
+            TransItemCollectionMode::Eager => {
+                true
+            }
+            TransItemCollectionMode::Lazy => {
+                self.entry_fn == Some(def_id) ||
+                self.tcx.is_exported_symbol(def_id)
+            }
+        }
+    }
+}
+
 fn item_has_type_parameters<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> bool {
     let generics = tcx.generics_of(def_id);
     generics.parent_types as usize + generics.types.len() > 0
diff --git a/src/librustc_trans_utils/lib.rs b/src/librustc_trans_utils/lib.rs
index 6a341a1e7d3..c460752d75e 100644
--- a/src/librustc_trans_utils/lib.rs
+++ b/src/librustc_trans_utils/lib.rs
@@ -107,11 +107,11 @@ pub fn find_exported_symbols(tcx: TyCtxt) -> NodeSet {
                 node: hir::ImplItemKind::Method(..), .. }) => {
                 let def_id = tcx.hir.local_def_id(id);
                 let generics = tcx.generics_of(def_id);
-                let attributes = tcx.get_attrs(def_id);
                 (generics.parent_types == 0 && generics.types.is_empty()) &&
                 // Functions marked with #[inline] are only ever translated
                 // with "internal" linkage and are never exported.
-                !attr::requests_inline(&attributes)
+                !attr::requests_inline(&tcx.get_attrs(def_id)) &&
+                !tcx.is_const_fn(def_id)
             }
 
             _ => false