unify the 2 impl indexes

Author: Ariel Ben-Yehuda

src/librustc/metadata/common.rs

@@ -133,8 +133,7 @@ enum_from_u32! {
         tag_table_method_map = 0x5f,
         // GAP 0x60
         tag_table_adjustments = 0x61,
-        // GAP 0x62, 0x63
-            // GAP 0x64, 0x65
+        // GAP 0x62, 0x63, 0x64, 0x65
         tag_table_upvar_capture_map = 0x66,
         // GAP 0x67, 0x68
         tag_table_const_qualif = 0x69,
@@ -163,22 +162,17 @@ 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;
-
-// GAP 0x79, 0x7a
-
+pub const tag_items_data_item_inherent_impl: usize = 0x79;
+// GAP 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
-// GAP 0x7e
-
 pub const tag_impls: usize = 0x109; // top-level only
-pub const tag_impls_impl: usize = 0x7f;
-pub const tag_impls_impl_trait_def_id: usize = 0x8d;
+pub const tag_impls_trait: usize = 0x7d;
+pub const tag_impls_trait_impl: usize = 0x7e;
 
-pub const tag_items_data_item_inherent_impl: usize = 0x80;
-pub const tag_items_data_item_extension_impl: usize = 0x81;
+// GAP 0x7f, 0x80, 0x81
 
 pub const tag_native_libraries: usize = 0x10a; // top-level only
 pub const tag_native_libraries_lib: usize = 0x82;
@@ -208,7 +202,7 @@ pub const tag_struct_field: usize = 0x8a;
 
 pub const tag_items_data_item_struct_ctor: usize = 0x8b;
 pub const tag_attribute_is_sugared_doc: usize = 0x8c;
-
+// GAP 0x8d
 pub const tag_items_data_region: usize = 0x8e;
 
 pub const tag_region_param_def: usize = 0x8f;

src/librustc/metadata/decoder.rs

@@ -1284,24 +1284,19 @@ pub fn each_implementation_for_trait<F>(cdata: Cmd,
                                         mut callback: F) where
     F: FnMut(DefId),
 {
-    if cdata.cnum == def_id.krate {
-        let item_doc = cdata.lookup_item(def_id.index);
-        for impl_doc in reader::tagged_docs(item_doc, tag_items_data_item_extension_impl) {
-            callback(item_def_id(impl_doc, cdata));
-        }
-        return;
-    }
-
     // Do a reverse lookup beforehand to avoid touching the crate_num
     // hash map in the loop below.
     if let Some(crate_local_did) = reverse_translate_def_id(cdata, def_id) {
         let def_id_u64 = def_to_u64(crate_local_did);
 
         let impls_doc = reader::get_doc(rbml::Doc::new(cdata.data()), tag_impls);
-        for impl_doc in reader::tagged_docs(impls_doc, tag_impls_impl) {
-            let impl_trait = reader::get_doc(impl_doc, tag_impls_impl_trait_def_id);
-            if reader::doc_as_u64(impl_trait) == def_id_u64 {
-                callback(item_def_id(impl_doc, cdata));
+        for trait_doc in reader::tagged_docs(impls_doc, tag_impls_trait) {
+            let trait_def_id = reader::get_doc(trait_doc, tag_def_id);
+            if reader::doc_as_u64(trait_def_id) != def_id_u64 {
+                continue;
+            }
+            for impl_doc in reader::tagged_docs(trait_doc, tag_impls_trait_impl) {
+                callback(translated_def_id(cdata, impl_doc));
             }
         }
     }

src/librustc/metadata/encoder.rs

@@ -865,20 +865,6 @@ fn encode_inherent_implementations(ecx: &EncodeContext,
     }
 }
 
-// Encodes the implementations of a trait defined in this crate.
-fn encode_extension_implementations(ecx: &EncodeContext,
-                                    rbml_w: &mut Encoder,
-                                    trait_def_id: DefId) {
-    assert!(trait_def_id.is_local());
-    let def = ecx.tcx.lookup_trait_def(trait_def_id);
-
-    def.for_each_impl(ecx.tcx, |impl_def_id| {
-        rbml_w.start_tag(tag_items_data_item_extension_impl);
-        encode_def_id(rbml_w, impl_def_id);
-        rbml_w.end_tag();
-    });
-}
-
 fn encode_stability(rbml_w: &mut Encoder, stab_opt: Option<&attr::Stability>) {
     stab_opt.map(|stab| {
         rbml_w.start_tag(tag_items_data_item_stability);
@@ -1256,9 +1242,6 @@ fn encode_info_for_item<'a, 'tcx>(ecx: &EncodeContext<'a, 'tcx>,
         }
         encode_path(rbml_w, path.clone());
 
-        // Encode the implementations of this trait.
-        encode_extension_implementations(ecx, rbml_w, def_id);
-
         // Encode inherent implementations for this trait.
         encode_inherent_implementations(ecx, rbml_w, def_id);
 
@@ -1763,53 +1746,44 @@ fn encode_struct_field_attrs(ecx: &EncodeContext,
 
 
 
-struct ImplVisitor<'a, 'b:'a, 'c:'a, 'tcx:'b> {
-    ecx: &'a EncodeContext<'b, 'tcx>,
-    rbml_w: &'a mut Encoder<'c>,
+struct ImplVisitor<'a, 'tcx:'a> {
+    tcx: &'a ty::ctxt<'tcx>,
+    impls: FnvHashMap<DefId, Vec<DefId>>
 }
 
-impl<'a, 'b, 'c, 'tcx, 'v> Visitor<'v> for ImplVisitor<'a, 'b, 'c, 'tcx> {
+impl<'a, 'tcx, 'v> Visitor<'v> for ImplVisitor<'a, 'tcx> {
     fn visit_item(&mut self, item: &hir::Item) {
-        if let hir::ItemImpl(_, _, _, Some(ref trait_ref), _, _) = item.node {
-            let def_id = self.ecx.tcx.def_map.borrow().get(&trait_ref.ref_id).unwrap().def_id();
-
-            // Load eagerly if this is an implementation of the Drop trait
-            // or if the trait is not defined in this crate.
-            if Some(def_id) == self.ecx.tcx.lang_items.drop_trait() ||
-                    def_id.krate != LOCAL_CRATE {
-                self.rbml_w.start_tag(tag_impls_impl);
-                encode_def_id(self.rbml_w, self.ecx.tcx.map.local_def_id(item.id));
-                self.rbml_w.wr_tagged_u64(tag_impls_impl_trait_def_id, def_to_u64(def_id));
-                self.rbml_w.end_tag();
+        if let hir::ItemImpl(..) = item.node {
+            let impl_id = self.tcx.map.local_def_id(item.id);
+            if let Some(trait_ref) = self.tcx.impl_trait_ref(impl_id) {
+                self.impls.entry(trait_ref.def_id)
+                    .or_insert(vec![])
+                    .push(impl_id);
             }
         }
         visit::walk_item(self, item);
     }
 }
 
-/// Encodes implementations that are eagerly loaded.
-///
-/// None of this is necessary in theory; we can load all implementations
-/// lazily. However, in two cases the optimizations to lazily load
-/// implementations are not yet implemented. These two cases, which require us
-/// to load implementations eagerly, are:
-///
-/// * Destructors (implementations of the Drop trait).
-///
-/// * Implementations of traits not defined in this crate.
+/// Encodes an index, mapping each trait to its (local) implementations.
 fn encode_impls<'a>(ecx: &'a EncodeContext,
                     krate: &hir::Crate,
                     rbml_w: &'a mut Encoder) {
-    rbml_w.start_tag(tag_impls);
+    let mut visitor = ImplVisitor {
+        tcx: ecx.tcx,
+        impls: FnvHashMap()
+    };
+    visit::walk_crate(&mut visitor, krate);
 
-    {
-        let mut visitor = ImplVisitor {
-            ecx: ecx,
-            rbml_w: rbml_w,
-        };
-        visit::walk_crate(&mut visitor, krate);
+    rbml_w.start_tag(tag_impls);
+    for (trait_, trait_impls) in visitor.impls {
+        rbml_w.start_tag(tag_impls_trait);
+        encode_def_id(rbml_w, trait_);
+        for impl_ in trait_impls {
+            rbml_w.wr_tagged_u64(tag_impls_trait_impl, def_to_u64(impl_));
+        }
+        rbml_w.end_tag();
     }
-
     rbml_w.end_tag();
 }
 

src/librustc/middle/astencode.rs

@@ -1319,7 +1319,7 @@ fn copy_item_types(dcx: &DecodeContext, ii: &InlinedItem, orig_did: DefId) {
                 if let Some(ctor_id) = def.ctor_id {
                     let ctor_did = dcx.tcx.lookup_adt_def(orig_did)
                         .struct_variant().ctor_id;
-                    println!("copying ctor {:?}", ctor_did);
+                    debug!("copying ctor {:?}", ctor_did);
                     copy_item_type(dcx, ctor_id, ctor_did);
                 }
             }