remove unneeded tags from metadata

stage1 release rlib sizes:
580890 liballoc-bb943c5a.rlib
1425558 liballoc_jemalloc-bb943c5a.rlib
10514 liballoc_system-bb943c5a.rlib
157192 libarena-bb943c5a.rlib
4316234 libcollections-bb943c5a.rlib
19580128 libcore-bb943c5a.rlib
199498 libflate-bb943c5a.rlib
249328 libfmt_macros-bb943c5a.rlib
560406 libgetopts-bb943c5a.rlib
233620 libgraphviz-bb943c5a.rlib
442964 liblibc-bb943c5a.rlib
190178 liblog-bb943c5a.rlib
778488 librand-bb943c5a.rlib
621972 librbml-bb943c5a.rlib
1415040 librustc_back-bb943c5a.rlib
38849082 librustc-bb943c5a.rlib
12862 librustc_bitflags-bb943c5a.rlib
2331690 librustc_borrowck-bb943c5a.rlib
616880 librustc_data_structures-bb943c5a.rlib
9386582 librustc_driver-bb943c5a.rlib
9600440 librustc_front-bb943c5a.rlib
1615058 librustc_lint-bb943c5a.rlib
79218480 librustc_llvm-bb943c5a.rlib
5020974 librustc_mir-bb943c5a.rlib
3535448 librustc_platform_intrinsics-bb943c5a.rlib
603640 librustc_privacy-bb943c5a.rlib
3163628 librustc_resolve-bb943c5a.rlib
14326646 librustc_trans-bb943c5a.rlib
12033174 librustc_typeck-bb943c5a.rlib
1838202 librustc_unicode-bb943c5a.rlib
15611582 librustdoc-bb943c5a.rlib
3056280 libserialize-bb943c5a.rlib
8954312 libstd-bb943c5a.rlib
30906736 libsyntax-bb943c5a.rlib
925480 libterm-bb943c5a.rlib
1377952 libtest-bb943c5a.rlib

src/librustc/metadata/common.rs

@@ -74,8 +74,6 @@ pub const tag_crate_dep_crate_name: usize = 0x36;
 pub const tag_crate_dep_hash: usize = 0x37;
 pub const tag_crate_dep_explicitly_linked: usize = 0x38; // top-level only
 
-pub const tag_mod_impl: usize = 0x39;
-
 pub const tag_item_trait_item: usize = 0x3a;
 
 pub const tag_item_trait_ref: usize = 0x3b;
@@ -89,7 +87,6 @@ pub const tag_path_len: usize = 0x3e;
 pub const tag_path_elem_mod: usize = 0x3f;
 pub const tag_path_elem_name: usize = 0x40;
 pub const tag_item_field: usize = 0x41;
-pub const tag_item_field_origin: usize = 0x42;
 
 pub const tag_item_variances: usize = 0x43;
 /*
@@ -119,8 +116,7 @@ enum_from_u32! {
 
         tag_tree = 0x51,
 
-        tag_id_range = 0x52,
-
+        // GAP 0x52
         tag_table = 0x53,
         // GAP 0x54, 0x55
         tag_table_def = 0x56,
@@ -129,30 +125,22 @@ enum_from_u32! {
         tag_table_freevars = 0x59,
         tag_table_tcache = 0x5a,
         tag_table_param_defs = 0x5b,
-        tag_table_mutbl = 0x5c,
-        tag_table_last_use = 0x5d,
-        tag_table_spill = 0x5e,
+        // GAP 0x5c, 0x5d, 0x5e
         tag_table_method_map = 0x5f,
-        tag_table_vtable_map = 0x60,
+        // GAP 0x60
         tag_table_adjustments = 0x61,
-        tag_table_moves_map = 0x62,
-        tag_table_capture_map = 0x63,
+        // GAP 0x62, 0x63
         tag_table_closure_tys = 0x64,
         tag_table_closure_kinds = 0x65,
         tag_table_upvar_capture_map = 0x66,
-        tag_table_capture_modes = 0x67,
-        // GAP 0x68
+        // GAP 0x67, 0x68
         tag_table_const_qualif = 0x69,
         tag_table_cast_kinds = 0x6a,
     }
 }
 
 pub const tag_item_trait_item_sort: usize = 0x70;
 
-pub const tag_item_trait_parent_sort: usize = 0x71;
-
-pub const tag_item_impl_type_basename: usize = 0x72;
-
 pub const tag_crate_triple: usize = 0x105; // top-level only
 
 pub const tag_dylib_dependency_formats: usize = 0x106; // top-level only
@@ -173,15 +161,15 @@ pub const tag_lang_items_missing: usize = 0x76;
 pub const tag_item_unnamed_field: usize = 0x77;
 pub const tag_items_data_item_visibility: usize = 0x78;
 
-pub const tag_item_method_tps: usize = 0x79;
+// GAP 0x79
 pub const tag_item_method_fty: usize = 0x7a;
 
 pub const tag_mod_child: usize = 0x7b;
 pub const tag_misc_info: usize = 0x108; // top-level only
 pub const tag_misc_info_crate_items: usize = 0x7c;
 
 // GAP 0x7d
-pub const tag_item_impl_vtables: usize = 0x7e;
+// GAP 0x7e
 
 pub const tag_impls: usize = 0x109; // top-level only
 pub const tag_impls_impl: usize = 0x7f;

src/librustc/metadata/csearch.rs

@@ -171,12 +171,6 @@ pub fn get_associated_consts<'tcx>(tcx: &ty::ctxt<'tcx>, def: DefId)
     decoder::get_associated_consts(cstore.intr.clone(), &*cdata, def.node, tcx)
 }
 
-pub fn get_type_name_if_impl(cstore: &cstore::CStore, def: DefId)
-                          -> Option<ast::Name> {
-    let cdata = cstore.get_crate_data(def.krate);
-    decoder::get_type_name_if_impl(&*cdata, def.node)
-}
-
 pub fn get_methods_if_impl(cstore: &cstore::CStore,
                                   def: DefId)
                                -> Option<Vec<MethodInfo> > {

src/librustc/metadata/decoder.rs

@@ -979,18 +979,6 @@ pub fn get_associated_consts<'tcx>(intr: Rc<IdentInterner>,
     }).collect()
 }
 
-pub fn get_type_name_if_impl(cdata: Cmd,
-                             node_id: ast::NodeId) -> Option<ast::Name> {
-    let item = cdata.lookup_item(node_id);
-    if item_family(item) != Impl {
-        return None;
-    }
-
-    reader::tagged_docs(item, tag_item_impl_type_basename).nth(0).map(|doc| {
-        token::intern(doc.as_str_slice())
-    })
-}
-
 pub fn get_methods_if_impl(intr: Rc<IdentInterner>,
                                   cdata: Cmd,
                                   node_id: ast::NodeId)

src/librustc/metadata/encoder.rs

@@ -78,10 +78,6 @@ fn encode_name(rbml_w: &mut Encoder, name: Name) {
     rbml_w.wr_tagged_str(tag_paths_data_name, &name.as_str());
 }
 
-fn encode_impl_type_basename(rbml_w: &mut Encoder, name: Name) {
-    rbml_w.wr_tagged_str(tag_item_impl_type_basename, &name.as_str());
-}
-
 fn encode_def_id(rbml_w: &mut Encoder, id: DefId) {
     rbml_w.wr_tagged_u64(tag_def_id, def_to_u64(id));
 }
@@ -253,8 +249,7 @@ fn encode_parent_item(rbml_w: &mut Encoder, id: DefId) {
 }
 
 fn encode_struct_fields(rbml_w: &mut Encoder,
-                        variant: ty::VariantDef,
-                        origin: DefId) {
+                        variant: ty::VariantDef) {
     for f in &variant.fields {
         if f.name == special_idents::unnamed_field.name {
             rbml_w.start_tag(tag_item_unnamed_field);
@@ -264,7 +259,6 @@ fn encode_struct_fields(rbml_w: &mut Encoder,
         }
         encode_struct_field_family(rbml_w, f.vis);
         encode_def_id(rbml_w, f.did);
-        rbml_w.wr_tagged_u64(tag_item_field_origin, def_to_u64(origin));
         rbml_w.end_tag();
     }
 }
@@ -311,7 +305,7 @@ fn encode_enum_variant_info(ecx: &EncodeContext,
         let stab = stability::lookup(ecx.tcx, vid);
         encode_stability(rbml_w, stab);
 
-        encode_struct_fields(rbml_w, variant, vid);
+        encode_struct_fields(rbml_w, variant);
 
         let specified_disr_val = variant.disr_val;
         if specified_disr_val != disr_val {
@@ -518,15 +512,6 @@ fn encode_info_for_mod(ecx: &EncodeContext,
                                  def_to_u64(DefId::local(auxiliary_node_id)));
             true
         });
-
-        if let hir::ItemImpl(..) = item.node {
-            let (name, did) = (item.name, item.id);
-            debug!("(encoding info for module) ... encoding impl {} ({}/{})",
-                   name,
-                   did, ecx.tcx.map.node_to_string(did));
-
-            rbml_w.wr_tagged_u64(tag_mod_impl, def_to_u64(DefId::local(did)));
-        }
     }
 
     encode_path(rbml_w, path.clone());
@@ -605,10 +590,6 @@ fn encode_item_sort(rbml_w: &mut Encoder, sort: char) {
     rbml_w.wr_tagged_u8(tag_item_trait_item_sort, sort as u8);
 }
 
-fn encode_parent_sort(rbml_w: &mut Encoder, sort: char) {
-    rbml_w.wr_tagged_u8(tag_item_trait_parent_sort, sort as u8);
-}
-
 fn encode_field<'a, 'tcx>(ecx: &EncodeContext<'a, 'tcx>,
                           rbml_w: &mut Encoder,
                           field: ty::FieldDef<'tcx>,
@@ -1147,7 +1128,7 @@ fn encode_info_for_item(ecx: &EncodeContext,
         /* Encode def_ids for each field and method
          for methods, write all the stuff get_trait_method
         needs to know*/
-        encode_struct_fields(rbml_w, variant, def_id);
+        encode_struct_fields(rbml_w, variant);
 
         encode_inlined_item(ecx, rbml_w, InlinedItemRef::Item(item));
 
@@ -1177,7 +1158,7 @@ fn encode_info_for_item(ecx: &EncodeContext,
           encode_trait_ref(rbml_w, ecx, trait_ref, tag_item_trait_ref);
           rbml_w.end_tag();
       }
-      hir::ItemImpl(unsafety, polarity, _, _, ref ty, ref ast_items) => {
+      hir::ItemImpl(unsafety, polarity, _, _, _, ref ast_items) => {
         // We need to encode information about the default methods we
         // have inherited, so we drive this based on the impl structure.
         let impl_items = tcx.impl_items.borrow();
@@ -1202,13 +1183,6 @@ fn encode_info_for_item(ecx: &EncodeContext,
             None => {}
         }
 
-        match ty.node {
-            hir::TyPath(None, ref path) if path.segments.len() == 1 => {
-                let name = path.segments.last().unwrap().identifier.name;
-                encode_impl_type_basename(rbml_w, name);
-            }
-            _ => {}
-        }
         for &item_def_id in items {
             rbml_w.start_tag(tag_item_impl_item);
             match item_def_id {
@@ -1412,8 +1386,6 @@ fn encode_info_for_item(ecx: &EncodeContext,
                 }
             }
 
-            encode_parent_sort(rbml_w, 't');
-
             let trait_item = &*ms[i];
             encode_attributes(rbml_w, &trait_item.attrs);
             match trait_item.node {