auto merge of #11161 : eddyb/rust/de-at-visitor, r=huonw

The primary user of `@T`/`P<T>` references from `Visitor` was `ast_map`, which in turn had two users (phase 3 in rustc and a step in loading items from metadata).
Both of them have been rewritten to use `ast_map` as a folder (this might speed up the compilation time of stage2 rustc by 100-200ms just because a fold + a visit are merged together).

src/librustc/driver/driver.rs

@@ -163,7 +163,8 @@ pub fn phase_1_parse_input(sess: Session, cfg: ast::CrateConfig, input: &input)
 /// standard library and prelude.
 pub fn phase_2_configure_and_expand(sess: Session,
                                     cfg: ast::CrateConfig,
-                                    mut crate: ast::Crate) -> ast::Crate {
+                                    mut crate: ast::Crate)
+                                    -> (ast::Crate, syntax::ast_map::map) {
     let time_passes = sess.time_passes();
 
     sess.building_library.set(session::building_library(sess.opts, &crate));
@@ -201,10 +202,8 @@ pub fn phase_2_configure_and_expand(sess: Session,
     crate = time(time_passes, "std injection", crate, |crate|
                  front::std_inject::maybe_inject_libstd_ref(sess, crate));
 
-    crate = time(time_passes, "assigning node ids", crate, |crate|
-                 front::assign_node_ids::assign_node_ids(sess, crate));
-
-    return crate;
+    time(time_passes, "assinging node ids and indexing ast", crate, |crate|
+         front::assign_node_ids_and_map::assign_node_ids_and_map(sess, crate))
 }
 
 pub struct CrateAnalysis {
@@ -219,13 +218,11 @@ pub struct CrateAnalysis {
 /// miscellaneous analysis passes on the crate. Return various
 /// structures carrying the results of the analysis.
 pub fn phase_3_run_analysis_passes(sess: Session,
-                                   crate: &ast::Crate) -> CrateAnalysis {
+                                   crate: &ast::Crate,
+                                   ast_map: syntax::ast_map::map) -> CrateAnalysis {
 
     let time_passes = sess.time_passes();
 
-    let ast_map = time(time_passes, "ast indexing", (), |_|
-                       syntax::ast_map::map_crate(sess.diagnostic(), crate));
-
     time(time_passes, "external crate/lib resolution", (), |_|
          creader::read_crates(sess, crate,
                               session::sess_os_to_meta_os(sess.targ_cfg.os),
@@ -260,8 +257,7 @@ pub fn phase_3_run_analysis_passes(sess: Session,
                             region_map, lang_items);
 
     // passes are timed inside typeck
-    let (method_map, vtable_map) = typeck::check_crate(
-        ty_cx, trait_map, crate);
+    let (method_map, vtable_map) = typeck::check_crate(ty_cx, trait_map, crate);
 
     // These next two const passes can probably be merged
     time(time_passes, "const marking", (), |_|
@@ -489,7 +485,7 @@ pub fn compile_input(sess: Session, cfg: ast::CrateConfig, input: &input,
     // large chunks of memory alive and we want to free them as soon as
     // possible to keep the peak memory usage low
     let (outputs, trans) = {
-        let expanded_crate = {
+        let (expanded_crate, ast_map) = {
             let crate = phase_1_parse_input(sess, cfg.clone(), input);
             if stop_after_phase_1(sess) { return; }
             phase_2_configure_and_expand(sess, cfg, crate)
@@ -501,7 +497,7 @@ pub fn compile_input(sess: Session, cfg: ast::CrateConfig, input: &input,
 
         if stop_after_phase_2(sess) { return; }
 
-        let analysis = phase_3_run_analysis_passes(sess, &expanded_crate);
+        let analysis = phase_3_run_analysis_passes(sess, &expanded_crate, ast_map);
         if stop_after_phase_3(sess) { return; }
         let trans = phase_4_translate_to_llvm(sess, expanded_crate,
                                               &analysis, outputs);
@@ -578,11 +574,12 @@ pub fn pretty_print_input(sess: Session,
                           ppm: PpMode) {
     let crate = phase_1_parse_input(sess, cfg.clone(), input);
 
-    let (crate, is_expanded) = match ppm {
+    let (crate, ast_map, is_expanded) = match ppm {
         PpmExpanded | PpmExpandedIdentified | PpmTyped => {
-            (phase_2_configure_and_expand(sess, cfg, crate), true)
+            let (crate, ast_map) = phase_2_configure_and_expand(sess, cfg, crate);
+            (crate, Some(ast_map), true)
         }
-        _ => (crate, false)
+        _ => (crate, None, false)
     };
 
     let annotation = match ppm {
@@ -592,7 +589,8 @@ pub fn pretty_print_input(sess: Session,
             } as @pprust::pp_ann
         }
         PpmTyped => {
-            let analysis = phase_3_run_analysis_passes(sess, &crate);
+            let ast_map = ast_map.expect("--pretty=typed missing ast_map");
+            let analysis = phase_3_run_analysis_passes(sess, &crate, ast_map);
             @TypedAnnotation {
                 analysis: analysis
             } as @pprust::pp_ann

src/librustc/front/assign_node_ids.rs → src/librustc/front/assign_node_ids_and_map.rs

@@ -1,4 +1,4 @@
-// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
+// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
@@ -11,22 +11,19 @@
 use driver::session::Session;
 
 use syntax::ast;
-use syntax::fold::ast_fold;
+use syntax::ast_map;
 
 struct NodeIdAssigner {
-    sess: Session,
+    sess: Session
 }
 
-impl ast_fold for NodeIdAssigner {
-    fn new_id(&mut self, old_id: ast::NodeId) -> ast::NodeId {
+impl ast_map::FoldOps for NodeIdAssigner {
+    fn new_id(&self, old_id: ast::NodeId) -> ast::NodeId {
         assert_eq!(old_id, ast::DUMMY_NODE_ID);
         self.sess.next_node_id()
     }
 }
 
-pub fn assign_node_ids(sess: Session, crate: ast::Crate) -> ast::Crate {
-    let mut fold = NodeIdAssigner {
-        sess: sess,
-    };
-    fold.fold_crate(crate)
+pub fn assign_node_ids_and_map(sess: Session, crate: ast::Crate) -> (ast::Crate, ast_map::map) {
+    ast_map::map_crate(sess.diagnostic(), crate, NodeIdAssigner { sess: sess })
 }

src/librustc/front/feature_gate.rs

@@ -119,7 +119,7 @@ impl Visitor<()> for Context {
         visit::walk_view_item(self, i, ())
     }
 
-    fn visit_item(&mut self, i: @ast::item, _:()) {
+    fn visit_item(&mut self, i: &ast::item, _:()) {
         for attr in i.attrs.iter() {
             if "thread_local" == attr.name() {
                 self.gate_feature("thread_local", i.span,
@@ -187,7 +187,7 @@ impl Visitor<()> for Context {
         visit::walk_ty(self, t, ());
     }
 
-    fn visit_expr(&mut self, e: @ast::Expr, _: ()) {
+    fn visit_expr(&mut self, e: &ast::Expr, _: ()) {
         match e.node {
             ast::ExprUnary(_, ast::UnBox, _) |
             ast::ExprVstore(_, ast::ExprVstoreBox) => {

src/librustc/lib.rs

@@ -81,7 +81,7 @@ pub mod front {
     pub mod config;
     pub mod test;
     pub mod std_inject;
-    pub mod assign_node_ids;
+    pub mod assign_node_ids_and_map;
     pub mod feature_gate;
 }
 

src/librustc/metadata/creader.rs

@@ -58,11 +58,11 @@ struct ReadCrateVisitor<'a> {
 }
 
 impl<'a> visit::Visitor<()> for ReadCrateVisitor<'a> {
-    fn visit_view_item(&mut self, a:&ast::view_item, _:()) {
+    fn visit_view_item(&mut self, a: &ast::view_item, _: ()) {
         visit_view_item(self.e, a);
         visit::walk_view_item(self, a, ());
     }
-    fn visit_item(&mut self, a:@ast::item, _:()) {
+    fn visit_item(&mut self, a: &ast::item, _: ()) {
         visit_item(self.e, a);
         visit::walk_item(self, a, ());
     }
@@ -164,7 +164,7 @@ fn visit_view_item(e: &mut Env, i: &ast::view_item) {
   }
 }
 
-fn visit_item(e: &Env, i: @ast::item) {
+fn visit_item(e: &Env, i: &ast::item) {
     match i.node {
         ast::item_foreign_mod(ref fm) => {
             if fm.abis.is_rust() || fm.abis.is_intrinsic() {

src/librustc/metadata/encoder.rs

@@ -50,10 +50,17 @@ use writer = extra::ebml::writer;
 // used by astencode:
 type abbrev_map = @RefCell<HashMap<ty::t, tyencode::ty_abbrev>>;
 
+/// A borrowed version of ast::inlined_item.
+pub enum InlinedItemRef<'a> {
+    ii_item_ref(&'a ast::item),
+    ii_method_ref(ast::DefId, bool, &'a ast::method),
+    ii_foreign_ref(&'a ast::foreign_item)
+}
+
 pub type encode_inlined_item<'a> = 'a |ecx: &EncodeContext,
-                                             ebml_w: &mut writer::Encoder,
-                                             path: &[ast_map::path_elt],
-                                             ii: ast::inlined_item|;
+                                       ebml_w: &mut writer::Encoder,
+                                       path: &[ast_map::path_elt],
+                                       ii: InlinedItemRef|;
 
 pub struct EncodeParams<'a> {
     diag: @SpanHandler,
@@ -837,13 +844,13 @@ fn encode_info_for_method(ecx: &EncodeContext,
         None => ()
     }
 
-    for ast_method in ast_method_opt.iter() {
+    for &ast_method in ast_method_opt.iter() {
         let num_params = tpt.generics.type_param_defs.len();
         if num_params > 0u || is_default_impl
             || should_inline(ast_method.attrs) {
             (ecx.encode_inlined_item)(
                 ecx, ebml_w, impl_path,
-                ii_method(local_def(parent_id), false, *ast_method));
+                ii_method_ref(local_def(parent_id), false, ast_method));
         } else {
             encode_symbol(ecx, ebml_w, m.def_id.node);
         }
@@ -915,13 +922,13 @@ fn encode_extension_implementations(ecx: &EncodeContext,
 
 fn encode_info_for_item(ecx: &EncodeContext,
                         ebml_w: &mut writer::Encoder,
-                        item: @item,
+                        item: &item,
                         index: @RefCell<~[entry<i64>]>,
                         path: &[ast_map::path_elt],
                         vis: ast::visibility) {
     let tcx = ecx.tcx;
 
-    fn add_to_index(item: @item, ebml_w: &writer::Encoder,
+    fn add_to_index(item: &item, ebml_w: &writer::Encoder,
                      index: @RefCell<~[entry<i64>]>) {
         let mut index = index.borrow_mut();
         index.get().push(entry {
@@ -958,7 +965,7 @@ fn encode_info_for_item(ecx: &EncodeContext,
         }
 
         if !non_inlineable {
-            (ecx.encode_inlined_item)(ecx, ebml_w, path, ii_item(item));
+            (ecx.encode_inlined_item)(ecx, ebml_w, path, ii_item_ref(item));
         }
         encode_visibility(ebml_w, vis);
         ebml_w.end_tag();
@@ -974,7 +981,7 @@ fn encode_info_for_item(ecx: &EncodeContext,
         encode_path(ecx, ebml_w, path, ast_map::path_name(item.ident));
         encode_attributes(ebml_w, item.attrs);
         if tps_len > 0u || should_inline(item.attrs) {
-            (ecx.encode_inlined_item)(ecx, ebml_w, path, ii_item(item));
+            (ecx.encode_inlined_item)(ecx, ebml_w, path, ii_item_ref(item));
         } else {
             encode_symbol(ecx, ebml_w, item.id);
         }
@@ -1032,7 +1039,7 @@ fn encode_info_for_item(ecx: &EncodeContext,
         for v in (*enum_definition).variants.iter() {
             encode_variant_id(ebml_w, local_def(v.node.id));
         }
-        (ecx.encode_inlined_item)(ecx, ebml_w, path, ii_item(item));
+        (ecx.encode_inlined_item)(ecx, ebml_w, path, ii_item_ref(item));
         encode_path(ecx, ebml_w, path, ast_map::path_name(item.ident));
 
         // Encode inherent implementations for this enumeration.
@@ -1077,7 +1084,7 @@ fn encode_info_for_item(ecx: &EncodeContext,
         needs to know*/
         encode_struct_fields(ecx, ebml_w, struct_def);
 
-        (ecx.encode_inlined_item)(ecx, ebml_w, path, ii_item(item));
+        (ecx.encode_inlined_item)(ecx, ebml_w, path, ii_item_ref(item));
 
         // Encode inherent implementations for this structure.
         encode_inherent_implementations(ecx, ebml_w, def_id);
@@ -1272,7 +1279,7 @@ fn encode_info_for_item(ecx: &EncodeContext,
                     encode_method_sort(ebml_w, 'p');
                     (ecx.encode_inlined_item)(
                         ecx, ebml_w, path,
-                        ii_method(def_id, true, m));
+                        ii_method_ref(def_id, true, m));
                 }
             }
 
@@ -1288,7 +1295,7 @@ fn encode_info_for_item(ecx: &EncodeContext,
 
 fn encode_info_for_foreign_item(ecx: &EncodeContext,
                                 ebml_w: &mut writer::Encoder,
-                                nitem: @foreign_item,
+                                nitem: &foreign_item,
                                 index: @RefCell<~[entry<i64>]>,
                                 path: &ast_map::path,
                                 abi: AbiSet) {
@@ -1309,7 +1316,7 @@ fn encode_info_for_foreign_item(ecx: &EncodeContext,
                                &lookup_item_type(ecx.tcx,local_def(nitem.id)));
         encode_name(ecx, ebml_w, nitem.ident);
         if abi.is_intrinsic() {
-            (ecx.encode_inlined_item)(ecx, ebml_w, *path, ii_foreign(nitem));
+            (ecx.encode_inlined_item)(ecx, ebml_w, *path, ii_foreign_ref(nitem));
         } else {
             encode_symbol(ecx, ebml_w, nitem.id);
         }
@@ -1331,9 +1338,9 @@ fn encode_info_for_foreign_item(ecx: &EncodeContext,
     ebml_w.end_tag();
 }
 
-fn my_visit_expr(_e:@Expr) { }
+fn my_visit_expr(_e: &Expr) { }
 
-fn my_visit_item(i: @item,
+fn my_visit_item(i: &item,
                  items: ast_map::map,
                  ebml_w: &mut writer::Encoder,
                  ecx_ptr: *int,
@@ -1352,7 +1359,7 @@ fn my_visit_item(i: @item,
     }
 }
 
-fn my_visit_foreign_item(ni: @foreign_item,
+fn my_visit_foreign_item(ni: &foreign_item,
                          items: ast_map::map,
                          ebml_w: &mut writer::Encoder,
                          ecx_ptr:*int,
@@ -1391,19 +1398,19 @@ struct EncodeVisitor<'a,'b> {
 }
 
 impl<'a,'b> visit::Visitor<()> for EncodeVisitor<'a,'b> {
-    fn visit_expr(&mut self, ex:@Expr, _:()) {
+    fn visit_expr(&mut self, ex: &Expr, _: ()) {
         visit::walk_expr(self, ex, ());
         my_visit_expr(ex);
     }
-    fn visit_item(&mut self, i:@item, _:()) {
+    fn visit_item(&mut self, i: &item, _: ()) {
         visit::walk_item(self, i, ());
         my_visit_item(i,
                       self.items,
                       self.ebml_w_for_visit_item,
                       self.ecx_ptr,
                       self.index);
     }
-    fn visit_foreign_item(&mut self, ni:@foreign_item, _:()) {
+    fn visit_foreign_item(&mut self, ni: &foreign_item, _: ()) {
         visit::walk_foreign_item(self, ni, ());
         my_visit_foreign_item(ni,
                               self.items,
@@ -1692,7 +1699,7 @@ struct ImplVisitor<'a,'b> {
 }
 
 impl<'a,'b> Visitor<()> for ImplVisitor<'a,'b> {
-    fn visit_item(&mut self, item: @item, _: ()) {
+    fn visit_item(&mut self, item: &item, _: ()) {
         match item.node {
             item_impl(_, Some(ref trait_ref), _, _) => {
                 let def_map = self.ecx.tcx.def_map;