Auto merge of rust-lang#61484 - nnethercote:avoid-more-hygiene-lookups, r=petrochenkov

Avoid more hygiene lookups

Mostly by combining multiple `HygieneData::with` calls into a single call on hot paths.

r? @petrochenkov

Author: bors

src/librustc/ty/mod.rs

@@ -3089,7 +3089,8 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         // comparison fails frequently, and we want to avoid the expensive
         // `modern()` calls required for the span comparison whenever possible.
         use_name.name == def_name.name &&
-        self.adjust_ident(use_name, def_parent_def_id).span.ctxt() == def_name.modern().span.ctxt()
+        use_name.span.ctxt().hygienic_eq(def_name.span.ctxt(),
+                                         self.expansion_that_defined(def_parent_def_id))
     }
 
     fn expansion_that_defined(self, scope: DefId) -> Mark {
@@ -3100,15 +3101,13 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
     }
 
     pub fn adjust_ident(self, mut ident: Ident, scope: DefId) -> Ident {
-        ident = ident.modern();
-        ident.span.adjust(self.expansion_that_defined(scope));
+        ident.span.modernize_and_adjust(self.expansion_that_defined(scope));
         ident
     }
 
     pub fn adjust_ident_and_get_scope(self, mut ident: Ident, scope: DefId, block: hir::HirId)
                                       -> (Ident, DefId) {
-        ident = ident.modern();
-        let scope = match ident.span.adjust(self.expansion_that_defined(scope)) {
+        let scope = match ident.span.modernize_and_adjust(self.expansion_that_defined(scope)) {
             Some(actual_expansion) =>
                 self.hir().definitions().parent_module_of_macro_def(actual_expansion),
             None => self.hir().get_module_parent_by_hir_id(block),

src/librustc/ty/query/on_disk_cache.rs

@@ -844,9 +844,8 @@ impl<'enc, 'a, 'tcx, E> SpecializedEncoder<Span> for CacheEncoder<'enc, 'a, 'tcx
         if span_data.ctxt == SyntaxContext::empty() {
             TAG_NO_EXPANSION_INFO.encode(self)
         } else {
-            let mark = span_data.ctxt.outer();
-
-            if let Some(expn_info) = mark.expn_info() {
+            let (mark, expn_info) = span_data.ctxt.outer_and_expn_info();
+            if let Some(expn_info) = expn_info {
                 if let Some(pos) = self.expn_info_shorthands.get(&mark).cloned() {
                     TAG_EXPANSION_INFO_SHORTHAND.encode(self)?;
                     pos.encode(self)

src/librustc_codegen_ssa/mir/mod.rs

@@ -128,14 +128,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             // Walk up the macro expansion chain until we reach a non-expanded span.
             // We also stop at the function body level because no line stepping can occur
             // at the level above that.
-            let mut span = source_info.span;
-            while span.ctxt() != NO_EXPANSION && span.ctxt() != self.mir.span.ctxt() {
-                if let Some(info) = span.ctxt().outer_expn_info() {
-                    span = info.call_site;
-                } else {
-                    break;
-                }
-            }
+            let span = syntax_pos::hygiene::walk_chain(source_info.span, self.mir.span.ctxt());
             let scope = self.scope_metadata_for_loc(source_info.scope, span.lo());
             // Use span of the outermost expansion site, while keeping the original lexical scope.
             (scope, span)

src/librustc_resolve/lib.rs

@@ -2330,14 +2330,12 @@ impl<'a> Resolver<'a> {
         let orig_current_module = self.current_module;
         match module {
             ModuleOrUniformRoot::Module(module) => {
-                ident.span = ident.span.modern();
-                if let Some(def) = ident.span.adjust(module.expansion) {
+                if let Some(def) = ident.span.modernize_and_adjust(module.expansion) {
                     self.current_module = self.macro_def_scope(def);
                 }
             }
             ModuleOrUniformRoot::ExternPrelude => {
-                ident.span = ident.span.modern();
-                ident.span.adjust(Mark::root());
+                ident.span.modernize_and_adjust(Mark::root());
             }
             ModuleOrUniformRoot::CrateRootAndExternPrelude |
             ModuleOrUniformRoot::CurrentScope => {
@@ -4525,7 +4523,7 @@ impl<'a> Resolver<'a> {
                 let mut ident = ident;
                 if ident.span.glob_adjust(
                     module.expansion,
-                    binding.span.ctxt().modern(),
+                    binding.span,
                 ).is_none() {
                     continue
                 }

src/librustc_resolve/resolve_imports.rs

@@ -388,7 +388,7 @@ impl<'a> Resolver<'a> {
                 None => return Err((Undetermined, Weak::Yes)),
             };
             let (orig_current_module, mut ident) = (self.current_module, ident.modern());
-            match ident.span.glob_adjust(module.expansion, glob_import.span.ctxt().modern()) {
+            match ident.span.glob_adjust(module.expansion, glob_import.span) {
                 Some(Some(def)) => self.current_module = self.macro_def_scope(def),
                 Some(None) => {}
                 None => continue,
@@ -605,8 +605,7 @@ impl<'a> Resolver<'a> {
         // Define `binding` in `module`s glob importers.
         for directive in module.glob_importers.borrow_mut().iter() {
             let mut ident = ident.modern();
-            let scope = match ident.span.reverse_glob_adjust(module.expansion,
-                                                             directive.span.ctxt().modern()) {
+            let scope = match ident.span.reverse_glob_adjust(module.expansion, directive.span) {
                 Some(Some(def)) => self.macro_def_scope(def),
                 Some(None) => directive.parent_scope.module,
                 None => continue,
@@ -1359,8 +1358,7 @@ impl<'a, 'b:'a> ImportResolver<'a, 'b> {
             resolution.borrow().binding().map(|binding| (ident, binding))
         }).collect::<Vec<_>>();
         for ((mut ident, ns), binding) in bindings {
-            let scope = match ident.span.reverse_glob_adjust(module.expansion,
-                                                             directive.span.ctxt().modern()) {
+            let scope = match ident.span.reverse_glob_adjust(module.expansion, directive.span) {
                 Some(Some(def)) => self.macro_def_scope(def),
                 Some(None) => self.current_module,
                 None => continue,

src/libsyntax/parse/parser.rs

@@ -2083,13 +2083,6 @@ impl<'a> Parser<'a> {
                     hi = path.span;
                     return Ok(self.mk_expr(lo.to(hi), ExprKind::Path(Some(qself), path), attrs));
                 }
-                if self.span.rust_2018() && self.check_keyword(kw::Async) {
-                    return if self.is_async_block() { // check for `async {` and `async move {`
-                        self.parse_async_block(attrs)
-                    } else {
-                        self.parse_lambda_expr(attrs)
-                    };
-                }
                 if self.check_keyword(kw::Move) || self.check_keyword(kw::Static) {
                     return self.parse_lambda_expr(attrs);
                 }
@@ -2161,6 +2154,16 @@ impl<'a> Parser<'a> {
                     assert!(self.eat_keyword(kw::Try));
                     return self.parse_try_block(lo, attrs);
                 }
+
+                // Span::rust_2018() is somewhat expensive; don't get it repeatedly.
+                let is_span_rust_2018 = self.span.rust_2018();
+                if is_span_rust_2018 && self.check_keyword(kw::Async) {
+                    return if self.is_async_block() { // check for `async {` and `async move {`
+                        self.parse_async_block(attrs)
+                    } else {
+                        self.parse_lambda_expr(attrs)
+                    };
+                }
                 if self.eat_keyword(kw::Return) {
                     if self.token.can_begin_expr() {
                         let e = self.parse_expr()?;
@@ -2196,7 +2199,7 @@ impl<'a> Parser<'a> {
                     db.span_label(self.span, "expected expression");
                     db.note("variable declaration using `let` is a statement");
                     return Err(db);
-                } else if self.span.rust_2018() && self.eat_keyword(kw::Await) {
+                } else if is_span_rust_2018 && self.eat_keyword(kw::Await) {
                     let (await_hi, e_kind) = self.parse_await_macro_or_alt(lo, self.prev_span)?;
                     hi = await_hi;
                     ex = e_kind;