remove register_reads

The reads will occur naturally as the HIR/MIR is fetched from the
tracked tables, and this winds up adding reads to the hir of foreign
def-ids somehow.

Author: nikomatsakis

src/librustc_trans/trans_item.rs

@@ -83,8 +83,6 @@ impl<'a, 'tcx> TransItem<'tcx> {
         // that the incoming edges to a particular fn are from a
         // particular set.
 
-        self.register_reads(ccx);
-
         match *self {
             TransItem::Static(node_id) => {
                 let def_id = ccx.tcx().map.local_def_id(node_id);
@@ -120,46 +118,6 @@ impl<'a, 'tcx> TransItem<'tcx> {
                ccx.codegen_unit().name());
     }
 
-    /// If necessary, creates a subtask for trans'ing a particular item and registers reads on
-    /// `TypeckItemBody` and `Hir`.
-    fn register_reads(&self, ccx: &CrateContext<'a, 'tcx>) {
-        let tcx = ccx.tcx();
-        let def_id = match *self {
-            TransItem::Static(node_id) => {
-                tcx.map.local_def_id(node_id)
-            }
-            TransItem::Fn(instance) => {
-                if let Some(node) = tcx.map.as_local_node_id(instance.def) {
-                    if let hir_map::Node::NodeItem(_) = tcx.map.get(node) {
-                        // This already is a "real" item
-                        instance.def
-                    } else {
-                        // Get the enclosing item and register a read on it
-                        tcx.map.get_parent_did(node)
-                    }
-                } else {
-                    // Translating an inlined item from another crate? Don't track anything.
-                    return;
-                }
-            }
-            TransItem::DropGlue(_) => {
-                // Nothing to track for drop glue
-                return;
-            }
-        };
-
-        tcx.dep_graph.with_task(DepNode::TransCrateItem(def_id), || {
-            tcx.dep_graph.read(DepNode::Hir(def_id));
-
-            // We are going to be accessing various tables
-            // generated by TypeckItemBody; we also assume
-            // that the body passes type check. These tables
-            // are not individually tracked, so just register
-            // a read here.
-            tcx.dep_graph.read(DepNode::TypeckItemBody(def_id));
-        });
-    }
-
     pub fn predefine(&self,
                      ccx: &CrateContext<'a, 'tcx>,
                      linkage: llvm::Linkage) {