Pass symbols to ExtCtxt::std_path instead of strings.

Because this function is hot.

Also remove the dead `ty_option` function.

Author: nnethercote

Diff for: src/libsyntax/ext/base.rs

@@ -969,10 +969,10 @@ impl<'a> ExtCtxt<'a> {
     pub fn ident_of(&self, st: &str) -> ast::Ident {
         ast::Ident::from_str(st)
     }
-    pub fn std_path(&self, components: &[&str]) -> Vec<ast::Ident> {
+    pub fn std_path(&self, components: &[Symbol]) -> Vec<ast::Ident> {
         let def_site = DUMMY_SP.apply_mark(self.current_expansion.mark);
         iter::once(Ident::new(kw::DollarCrate, def_site))
-            .chain(components.iter().map(|s| self.ident_of(s)))
+            .chain(components.iter().map(|&s| Ident::with_empty_ctxt(s)))
             .collect()
     }
     pub fn name_of(&self, st: &str) -> ast::Name {

Diff for: src/libsyntax/ext/build.rs

@@ -3,11 +3,11 @@ use crate::attr;
 use crate::source_map::{dummy_spanned, respan, Spanned};
 use crate::ext::base::ExtCtxt;
 use crate::ptr::P;
-use crate::symbol::{Symbol, kw};
+use crate::symbol::{kw, sym, Symbol};
 use crate::ThinVec;
 
 use rustc_target::spec::abi::Abi;
-use syntax_pos::{Pos, Span, DUMMY_SP};
+use syntax_pos::{Pos, Span};
 
 pub trait AstBuilder {
     // paths
@@ -49,7 +49,6 @@ pub trait AstBuilder {
               ty: P<ast::Ty>,
               mutbl: ast::Mutability) -> P<ast::Ty>;
 
-    fn ty_option(&self, ty: P<ast::Ty>) -> P<ast::Ty>;
     fn ty_infer(&self, sp: Span) -> P<ast::Ty>;
 
     fn typaram(&self,
@@ -425,15 +424,6 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
                 ast::TyKind::Ptr(self.ty_mt(ty, mutbl)))
     }
 
-    fn ty_option(&self, ty: P<ast::Ty>) -> P<ast::Ty> {
-        self.ty_path(
-            self.path_all(DUMMY_SP,
-                          true,
-                          self.std_path(&["option", "Option"]),
-                          vec![ast::GenericArg::Type(ty)],
-                          Vec::new()))
-    }
-
     fn ty_infer(&self, span: Span) -> P<ast::Ty> {
         self.ty(span, ast::TyKind::Infer)
     }
@@ -735,7 +725,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
         self.expr(sp, ast::ExprKind::Array(exprs))
     }
     fn expr_vec_ng(&self, sp: Span) -> P<ast::Expr> {
-        self.expr_call_global(sp, self.std_path(&["vec", "Vec", "new"]),
+        self.expr_call_global(sp, self.std_path(&[sym::vec, sym::Vec, sym::new]),
                               Vec::new())
     }
     fn expr_vec_slice(&self, sp: Span, exprs: Vec<P<ast::Expr>>) -> P<ast::Expr> {
@@ -751,12 +741,12 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
 
 
     fn expr_some(&self, sp: Span, expr: P<ast::Expr>) -> P<ast::Expr> {
-        let some = self.std_path(&["option", "Option", "Some"]);
+        let some = self.std_path(&[sym::option, sym::Option, sym::Some]);
         self.expr_call_global(sp, some, vec![expr])
     }
 
     fn expr_none(&self, sp: Span) -> P<ast::Expr> {
-        let none = self.std_path(&["option", "Option", "None"]);
+        let none = self.std_path(&[sym::option, sym::Option, sym::None]);
         let none = self.path_global(sp, none);
         self.expr_path(none)
     }
@@ -780,7 +770,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
         let expr_loc_ptr = self.expr_addr_of(span, expr_loc_tuple);
         self.expr_call_global(
             span,
-            self.std_path(&["rt", "begin_panic"]),
+            self.std_path(&[sym::rt, sym::begin_panic]),
             vec![
                 self.expr_str(span, msg),
                 expr_loc_ptr])
@@ -791,19 +781,19 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
     }
 
     fn expr_ok(&self, sp: Span, expr: P<ast::Expr>) -> P<ast::Expr> {
-        let ok = self.std_path(&["result", "Result", "Ok"]);
+        let ok = self.std_path(&[sym::result, sym::Result, sym::Ok]);
         self.expr_call_global(sp, ok, vec![expr])
     }
 
     fn expr_err(&self, sp: Span, expr: P<ast::Expr>) -> P<ast::Expr> {
-        let err = self.std_path(&["result", "Result", "Err"]);
+        let err = self.std_path(&[sym::result, sym::Result, sym::Err]);
         self.expr_call_global(sp, err, vec![expr])
     }
 
     fn expr_try(&self, sp: Span, head: P<ast::Expr>) -> P<ast::Expr> {
-        let ok = self.std_path(&["result", "Result", "Ok"]);
+        let ok = self.std_path(&[sym::result, sym::Result, sym::Ok]);
         let ok_path = self.path_global(sp, ok);
-        let err = self.std_path(&["result", "Result", "Err"]);
+        let err = self.std_path(&[sym::result, sym::Result, sym::Err]);
         let err_path = self.path_global(sp, err);
 
         let binding_variable = self.ident_of("__try_var");
@@ -867,25 +857,25 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
     }
 
     fn pat_some(&self, span: Span, pat: P<ast::Pat>) -> P<ast::Pat> {
-        let some = self.std_path(&["option", "Option", "Some"]);
+        let some = self.std_path(&[sym::option, sym::Option, sym::Some]);
         let path = self.path_global(span, some);
         self.pat_tuple_struct(span, path, vec![pat])
     }
 
     fn pat_none(&self, span: Span) -> P<ast::Pat> {
-        let some = self.std_path(&["option", "Option", "None"]);
+        let some = self.std_path(&[sym::option, sym::Option, sym::None]);
         let path = self.path_global(span, some);
         self.pat_path(span, path)
     }
 
     fn pat_ok(&self, span: Span, pat: P<ast::Pat>) -> P<ast::Pat> {
-        let some = self.std_path(&["result", "Result", "Ok"]);
+        let some = self.std_path(&[sym::result, sym::Result, sym::Ok]);
         let path = self.path_global(span, some);
         self.pat_tuple_struct(span, path, vec![pat])
     }
 
     fn pat_err(&self, span: Span, pat: P<ast::Pat>) -> P<ast::Pat> {
-        let some = self.std_path(&["result", "Result", "Err"]);
+        let some = self.std_path(&[sym::result, sym::Result, sym::Err]);
         let path = self.path_global(span, some);
         self.pat_tuple_struct(span, path, vec![pat])
     }

Diff for: src/libsyntax_ext/deriving/clone.rs

@@ -7,7 +7,7 @@ use syntax::attr;
 use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ext::build::AstBuilder;
 use syntax::ptr::P;
-use syntax::symbol::{kw, sym};
+use syntax::symbol::{kw, sym, Symbol};
 use syntax_pos::Span;
 
 pub fn expand_deriving_clone(cx: &mut ExtCtxt<'_>,
@@ -115,7 +115,7 @@ fn cs_clone_shallow(name: &str,
         // set the expn ID so we can use the unstable struct.
         let span = span.with_ctxt(cx.backtrace());
         let assert_path = cx.path_all(span, true,
-                                        cx.std_path(&["clone", helper_name]),
+                                        cx.std_path(&[sym::clone, Symbol::intern(helper_name)]),
                                         vec![GenericArg::Type(ty)], vec![]);
         stmts.push(cx.stmt_let_type_only(span, cx.ty_path(assert_path)));
     }
@@ -157,7 +157,7 @@ fn cs_clone(name: &str,
             -> P<Expr> {
     let ctor_path;
     let all_fields;
-    let fn_path = cx.std_path(&["clone", "Clone", "clone"]);
+    let fn_path = cx.std_path(&[sym::clone, sym::Clone, sym::clone]);
     let subcall = |cx: &mut ExtCtxt<'_>, field: &FieldInfo<'_>| {
         let args = vec![cx.expr_addr_of(field.span, field.self_.clone())];
         cx.expr_call_global(field.span, fn_path.clone(), args)

Diff for: src/libsyntax_ext/deriving/cmp/eq.rs

@@ -6,7 +6,7 @@ use syntax::ast::{self, Expr, MetaItem, GenericArg};
 use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ext::build::AstBuilder;
 use syntax::ptr::P;
-use syntax::symbol::sym;
+use syntax::symbol::{sym, Symbol};
 use syntax_pos::Span;
 
 pub fn expand_deriving_eq(cx: &mut ExtCtxt<'_>,
@@ -54,7 +54,7 @@ fn cs_total_eq_assert(cx: &mut ExtCtxt<'_>,
         // set the expn ID so we can use the unstable struct.
         let span = span.with_ctxt(cx.backtrace());
         let assert_path = cx.path_all(span, true,
-                                        cx.std_path(&["cmp", helper_name]),
+                                        cx.std_path(&[sym::cmp, Symbol::intern(helper_name)]),
                                         vec![GenericArg::Type(ty)], vec![]);
         stmts.push(cx.stmt_let_type_only(span, cx.ty_path(assert_path)));
     }

Diff for: src/libsyntax_ext/deriving/cmp/ord.rs

@@ -55,9 +55,9 @@ pub fn ordering_collapsed(cx: &mut ExtCtxt<'_>,
 
 pub fn cs_cmp(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> P<Expr> {
     let test_id = cx.ident_of("cmp").gensym();
-    let equals_path = cx.path_global(span, cx.std_path(&["cmp", "Ordering", "Equal"]));
+    let equals_path = cx.path_global(span, cx.std_path(&[sym::cmp, sym::Ordering, sym::Equal]));
 
-    let cmp_path = cx.std_path(&["cmp", "Ord", "cmp"]);
+    let cmp_path = cx.std_path(&[sym::cmp, sym::Ord, sym::cmp]);
 
     // Builds:
     //

Diff for: src/libsyntax_ext/deriving/cmp/partial_ord.rs

@@ -8,7 +8,7 @@ use syntax::ast::{self, BinOpKind, Expr, MetaItem};
 use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ext::build::AstBuilder;
 use syntax::ptr::P;
-use syntax::symbol::sym;
+use syntax::symbol::{sym, Symbol};
 use syntax_pos::Span;
 
 pub fn expand_deriving_partial_ord(cx: &mut ExtCtxt<'_>,
@@ -114,11 +114,11 @@ pub fn some_ordering_collapsed(cx: &mut ExtCtxt<'_>,
 
 pub fn cs_partial_cmp(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> P<Expr> {
     let test_id = cx.ident_of("cmp").gensym();
-    let ordering = cx.path_global(span, cx.std_path(&["cmp", "Ordering", "Equal"]));
+    let ordering = cx.path_global(span, cx.std_path(&[sym::cmp, sym::Ordering, sym::Equal]));
     let ordering_expr = cx.expr_path(ordering.clone());
     let equals_expr = cx.expr_some(span, ordering_expr);
 
-    let partial_cmp_path = cx.std_path(&["cmp", "PartialOrd", "partial_cmp"]);
+    let partial_cmp_path = cx.std_path(&[sym::cmp, sym::PartialOrd, sym::partial_cmp]);
 
     // Builds:
     //
@@ -188,7 +188,8 @@ fn cs_op(less: bool,
          span: Span,
          substr: &Substructure<'_>) -> P<Expr> {
     let ordering_path = |cx: &mut ExtCtxt<'_>, name: &str| {
-        cx.expr_path(cx.path_global(span, cx.std_path(&["cmp", "Ordering", name])))
+        cx.expr_path(cx.path_global(
+            span, cx.std_path(&[sym::cmp, sym::Ordering, Symbol::intern(name)])))
     };
 
     let par_cmp = |cx: &mut ExtCtxt<'_>, span, self_f: P<Expr>, other_fs: &[P<Expr>], default| {
@@ -198,19 +199,19 @@ fn cs_op(less: bool,
         };
 
         // `PartialOrd::partial_cmp(self.fi, other.fi)`
-        let cmp_path = cx.expr_path(cx.path_global(span, cx.std_path(&["cmp",
-                                                                       "PartialOrd",
-                                                                       "partial_cmp"])));
+        let cmp_path = cx.expr_path(cx.path_global(span, cx.std_path(&[sym::cmp,
+                                                                       sym::PartialOrd,
+                                                                       sym::partial_cmp])));
         let cmp = cx.expr_call(span,
                                cmp_path,
                                vec![cx.expr_addr_of(span, self_f),
                                     cx.expr_addr_of(span, other_f.clone())]);
 
         let default = ordering_path(cx, default);
         // `Option::unwrap_or(_, Ordering::Equal)`
-        let unwrap_path = cx.expr_path(cx.path_global(span, cx.std_path(&["option",
-                                                                          "Option",
-                                                                          "unwrap_or"])));
+        let unwrap_path = cx.expr_path(cx.path_global(span, cx.std_path(&[sym::option,
+                                                                          sym::Option,
+                                                                          sym::unwrap_or])));
         cx.expr_call(span, unwrap_path, vec![cmp, default])
     };
 
@@ -256,9 +257,9 @@ fn cs_op(less: bool,
 
             // `Ordering::then_with(Option::unwrap_or(..), ..)`
             let then_with_path = cx.expr_path(cx.path_global(span,
-                                                             cx.std_path(&["cmp",
-                                                                           "Ordering",
-                                                                           "then_with"])));
+                                                             cx.std_path(&[sym::cmp,
+                                                                           sym::Ordering,
+                                                                           sym::then_with])));
             cx.expr_call(span, then_with_path, vec![par_cmp, cx.lambda0(span, subexpr)])
         },
         |cx, args| {

Diff for: src/libsyntax_ext/deriving/default.rs

@@ -6,7 +6,7 @@ use syntax::ast::{Expr, MetaItem};
 use syntax::ext::base::{Annotatable, DummyResult, ExtCtxt};
 use syntax::ext::build::AstBuilder;
 use syntax::ptr::P;
-use syntax::symbol::sym;
+use syntax::symbol::{kw, sym};
 use syntax::span_err;
 use syntax_pos::Span;
 
@@ -47,7 +47,8 @@ fn default_substructure(cx: &mut ExtCtxt<'_>,
                         trait_span: Span,
                         substr: &Substructure<'_>)
                         -> P<Expr> {
-    let default_ident = cx.std_path(&["default", "Default", "default"]);
+    // Note that `kw::Default` is "default" and `sym::Default` is "Default"!
+    let default_ident = cx.std_path(&[kw::Default, sym::Default, kw::Default]);
     let default_call = |span| cx.expr_call_global(span, default_ident.clone(), Vec::new());
 
     return match *substr.fields {

Diff for: src/libsyntax_ext/deriving/hash.rs

@@ -6,6 +6,7 @@ use syntax::ast::{Expr, MetaItem, Mutability};
 use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ext::build::AstBuilder;
 use syntax::ptr::P;
+use syntax::symbol::sym;
 use syntax_pos::Span;
 
 pub fn expand_deriving_hash(cx: &mut ExtCtxt<'_>,
@@ -60,7 +61,7 @@ fn hash_substructure(cx: &mut ExtCtxt<'_>, trait_span: Span, substr: &Substructu
     };
     let call_hash = |span, thing_expr| {
         let hash_path = {
-            let strs = cx.std_path(&["hash", "Hash", "hash"]);
+            let strs = cx.std_path(&[sym::hash, sym::Hash, sym::hash]);
 
             cx.expr_path(cx.path_global(span, strs))
         };

Diff for: src/libsyntax_ext/deriving/mod.rs

@@ -150,7 +150,7 @@ fn call_intrinsic(cx: &ExtCtxt<'_>,
         mark.set_expn_info(info);
         span = span.with_ctxt(SyntaxContext::empty().apply_mark(mark));
     }
-    let path = cx.std_path(&["intrinsics", intrinsic]);
+    let path = cx.std_path(&[sym::intrinsics, Symbol::intern(intrinsic)]);
     let call = cx.expr_call_global(span, path, args);
 
     cx.expr_block(P(ast::Block {

Diff for: src/libsyntax_ext/env.rs

@@ -27,7 +27,7 @@ pub fn expand_option_env<'cx>(cx: &'cx mut ExtCtxt<'_>,
             let lt = cx.lifetime(sp, Ident::with_empty_ctxt(kw::StaticLifetime));
             cx.expr_path(cx.path_all(sp,
                                      true,
-                                     cx.std_path(&["option", "Option", "None"]),
+                                     cx.std_path(&[sym::option, sym::Option, sym::None]),
                                      vec![GenericArg::Type(cx.ty_rptr(sp,
                                                      cx.ty_ident(sp,
                                                                  Ident::with_empty_ctxt(sym::str)),
@@ -37,7 +37,7 @@ pub fn expand_option_env<'cx>(cx: &'cx mut ExtCtxt<'_>,
         }
         Ok(s) => {
             cx.expr_call_global(sp,
-                                cx.std_path(&["option", "Option", "Some"]),
+                                cx.std_path(&[sym::option, sym::Option, sym::Some]),
                                 vec![cx.expr_str(sp, Symbol::intern(&s))])
         }
     };

Diff for: src/libsyntax_ext/format.rs

@@ -387,7 +387,7 @@ impl<'a, 'b> Context<'a, 'b> {
     }
 
     fn rtpath(ecx: &ExtCtxt<'_>, s: &str) -> Vec<ast::Ident> {
-        ecx.std_path(&["fmt", "rt", "v1", s])
+        ecx.std_path(&[sym::fmt, sym::rt, sym::v1, Symbol::intern(s)])
     }
 
     fn build_count(&self, c: parse::Count<'_>) -> P<ast::Expr> {
@@ -644,7 +644,7 @@ impl<'a, 'b> Context<'a, 'b> {
             ("new_v1_formatted", vec![pieces, args_slice, fmt])
         };
 
-        let path = self.ecx.std_path(&["fmt", "Arguments", fn_name]);
+        let path = self.ecx.std_path(&[sym::fmt, sym::Arguments, Symbol::intern(fn_name)]);
         self.ecx.expr_call_global(self.macsp, path, fn_args)
     }
 
@@ -675,14 +675,14 @@ impl<'a, 'b> Context<'a, 'b> {
                 }
             }
             Count => {
-                let path = ecx.std_path(&["fmt", "ArgumentV1", "from_usize"]);
+                let path = ecx.std_path(&[sym::fmt, sym::ArgumentV1, sym::from_usize]);
                 return ecx.expr_call_global(macsp, path, vec![arg]);
             }
         };
 
-        let path = ecx.std_path(&["fmt", trait_, "fmt"]);
+        let path = ecx.std_path(&[sym::fmt, Symbol::intern(trait_), sym::fmt]);
         let format_fn = ecx.path_global(sp, path);
-        let path = ecx.std_path(&["fmt", "ArgumentV1", "new"]);
+        let path = ecx.std_path(&[sym::fmt, sym::ArgumentV1, sym::new]);
         ecx.expr_call_global(macsp, path, vec![arg, ecx.expr_path(format_fn)])
     }
 }