Add and use more static symbols.

Note that the output of `unpretty-debug.stdout` has changed. In that
test the hash values are normalized from a symbol numbers to small
numbers like "0#0" and "0#1". The increase in the number of static
symbols must have caused the original numbers to contain more digits,
resulting in different pretty-printing prior to normalization.

Author: nnethercote

src/librustc_ast/expand/allocator.rs

@@ -9,7 +9,7 @@ pub enum AllocatorKind {
 }
 
 impl AllocatorKind {
-    pub fn fn_name(&self, base: &str) -> String {
+    pub fn fn_name(&self, base: Symbol) -> String {
         match *self {
             AllocatorKind::Global => format!("__rg_{}", base),
             AllocatorKind::Default => format!("__rdl_{}", base),
@@ -26,29 +26,29 @@ pub enum AllocatorTy {
 }
 
 pub struct AllocatorMethod {
-    pub name: &'static str,
+    pub name: Symbol,
     pub inputs: &'static [AllocatorTy],
     pub output: AllocatorTy,
 }
 
 pub static ALLOCATOR_METHODS: &[AllocatorMethod] = &[
     AllocatorMethod {
-        name: "alloc",
+        name: sym::alloc,
         inputs: &[AllocatorTy::Layout],
         output: AllocatorTy::ResultPtr,
     },
     AllocatorMethod {
-        name: "dealloc",
+        name: sym::dealloc,
         inputs: &[AllocatorTy::Ptr, AllocatorTy::Layout],
         output: AllocatorTy::Unit,
     },
     AllocatorMethod {
-        name: "realloc",
+        name: sym::realloc,
         inputs: &[AllocatorTy::Ptr, AllocatorTy::Layout, AllocatorTy::Usize],
         output: AllocatorTy::ResultPtr,
     },
     AllocatorMethod {
-        name: "alloc_zeroed",
+        name: sym::alloc_zeroed,
         inputs: &[AllocatorTy::Layout],
         output: AllocatorTy::ResultPtr,
     },
@@ -70,7 +70,7 @@ pub fn global_allocator_spans(krate: &ast::Crate) -> Vec<Span> {
         }
     }
 
-    let name = Symbol::intern(&AllocatorKind::Global.fn_name("alloc"));
+    let name = Symbol::intern(&AllocatorKind::Global.fn_name(sym::alloc));
     let mut f = Finder { name, spans: Vec::new() };
     visit::walk_crate(&mut f, krate);
     f.spans

src/librustc_attr/builtin.rs

@@ -1041,10 +1041,10 @@ pub fn find_transparency(
                 break;
             } else if let Some(value) = attr.value_str() {
                 transparency = Some((
-                    match &*value.as_str() {
-                        "transparent" => Transparency::Transparent,
-                        "semitransparent" => Transparency::SemiTransparent,
-                        "opaque" => Transparency::Opaque,
+                    match value {
+                        sym::transparent => Transparency::Transparent,
+                        sym::semitransparent => Transparency::SemiTransparent,
+                        sym::opaque => Transparency::Opaque,
                         _ => {
                             error = Some(TransparencyError::UnknownTransparency(value, attr.span));
                             continue;

src/librustc_builtin_macros/deriving/clone.rs

@@ -84,7 +84,7 @@ pub fn expand_deriving_clone(
         is_unsafe: false,
         supports_unions: true,
         methods: vec![MethodDef {
-            name: "clone",
+            name: sym::clone,
             generics: LifetimeBounds::empty(),
             explicit_self: borrowed_explicit_self(),
             args: Vec::new(),

src/librustc_builtin_macros/deriving/cmp/eq.rs

@@ -28,7 +28,7 @@ pub fn expand_deriving_eq(
         is_unsafe: false,
         supports_unions: true,
         methods: vec![MethodDef {
-            name: "assert_receiver_is_total_eq",
+            name: sym::assert_receiver_is_total_eq,
             generics: LifetimeBounds::empty(),
             explicit_self: borrowed_explicit_self(),
             args: vec![],

src/librustc_builtin_macros/deriving/cmp/ord.rs

@@ -26,7 +26,7 @@ pub fn expand_deriving_ord(
         is_unsafe: false,
         supports_unions: false,
         methods: vec![MethodDef {
-            name: "cmp",
+            name: sym::cmp,
             generics: LifetimeBounds::empty(),
             explicit_self: borrowed_explicit_self(),
             args: vec![(borrowed_self(), "other")],

src/librustc_builtin_macros/deriving/cmp/partial_eq.rs

@@ -92,9 +92,9 @@ pub fn expand_deriving_partial_eq(
     // avoid defining `ne` if we can
     // c-like enums, enums without any fields and structs without fields
     // can safely define only `eq`.
-    let mut methods = vec![md!("eq", cs_eq)];
+    let mut methods = vec![md!(sym::eq, cs_eq)];
     if !is_type_without_fields(item) {
-        methods.push(md!("ne", cs_ne));
+        methods.push(md!(sym::ne, cs_ne));
     }
 
     let trait_def = TraitDef {

src/librustc_builtin_macros/deriving/cmp/partial_ord.rs

@@ -49,7 +49,7 @@ pub fn expand_deriving_partial_ord(
     let attrs = vec![cx.attribute(inline)];
 
     let partial_cmp_def = MethodDef {
-        name: "partial_cmp",
+        name: sym::partial_cmp,
         generics: LifetimeBounds::empty(),
         explicit_self: borrowed_explicit_self(),
         args: vec![(borrowed_self(), "other")],
@@ -70,10 +70,10 @@ pub fn expand_deriving_partial_ord(
     } else {
         vec![
             partial_cmp_def,
-            md!("lt", true, false),
-            md!("le", true, true),
-            md!("gt", false, false),
-            md!("ge", false, true),
+            md!(sym::lt, true, false),
+            md!(sym::le, true, true),
+            md!(sym::gt, false, false),
+            md!(sym::ge, false, true),
         ]
     };
 
@@ -108,14 +108,14 @@ pub fn some_ordering_collapsed(
 ) -> P<ast::Expr> {
     let lft = cx.expr_ident(span, self_arg_tags[0]);
     let rgt = cx.expr_addr_of(span, cx.expr_ident(span, self_arg_tags[1]));
-    let op_str = match op {
-        PartialCmpOp => "partial_cmp",
-        LtOp => "lt",
-        LeOp => "le",
-        GtOp => "gt",
-        GeOp => "ge",
+    let op_sym = match op {
+        PartialCmpOp => sym::partial_cmp,
+        LtOp => sym::lt,
+        LeOp => sym::le,
+        GtOp => sym::gt,
+        GeOp => sym::ge,
     };
-    cx.expr_method_call(span, lft, cx.ident_of(op_str, span), vec![rgt])
+    cx.expr_method_call(span, lft, Ident::new(op_sym, span), vec![rgt])
 }
 
 pub fn cs_partial_cmp(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> P<Expr> {

src/librustc_builtin_macros/deriving/debug.rs

@@ -29,7 +29,7 @@ pub fn expand_deriving_debug(
         is_unsafe: false,
         supports_unions: false,
         methods: vec![MethodDef {
-            name: "fmt",
+            name: sym::fmt,
             generics: LifetimeBounds::empty(),
             explicit_self: borrowed_explicit_self(),
             args: vec![(fmtr, "f")],

src/librustc_builtin_macros/deriving/decodable.rs

@@ -8,7 +8,7 @@ use rustc_ast::ast;
 use rustc_ast::ast::{Expr, MetaItem, Mutability};
 use rustc_ast::ptr::P;
 use rustc_expand::base::{Annotatable, ExtCtxt};
-use rustc_span::symbol::Symbol;
+use rustc_span::symbol::{sym, Symbol};
 use rustc_span::Span;
 
 pub fn expand_deriving_rustc_decodable(
@@ -30,7 +30,7 @@ pub fn expand_deriving_rustc_decodable(
         is_unsafe: false,
         supports_unions: false,
         methods: vec![MethodDef {
-            name: "decode",
+            name: sym::decode,
             generics: LifetimeBounds {
                 lifetimes: Vec::new(),
                 bounds: vec![(

src/librustc_builtin_macros/deriving/default.rs

@@ -27,7 +27,7 @@ pub fn expand_deriving_default(
         is_unsafe: false,
         supports_unions: false,
         methods: vec![MethodDef {
-            name: "default",
+            name: kw::Default,
             generics: LifetimeBounds::empty(),
             explicit_self: None,
             args: Vec::new(),

src/librustc_builtin_macros/deriving/encodable.rs

@@ -92,7 +92,7 @@ use crate::deriving::pathvec_std;
 use rustc_ast::ast::{Expr, ExprKind, MetaItem, Mutability};
 use rustc_ast::ptr::P;
 use rustc_expand::base::{Annotatable, ExtCtxt};
-use rustc_span::symbol::Symbol;
+use rustc_span::symbol::{sym, Symbol};
 use rustc_span::Span;
 
 pub fn expand_deriving_rustc_encodable(
@@ -114,7 +114,7 @@ pub fn expand_deriving_rustc_encodable(
         is_unsafe: false,
         supports_unions: false,
         methods: vec![MethodDef {
-            name: "encode",
+            name: sym::encode,
             generics: LifetimeBounds {
                 lifetimes: Vec::new(),
                 bounds: vec![(

src/librustc_builtin_macros/deriving/generic/mod.rs

@@ -226,7 +226,7 @@ pub struct TraitDef<'a> {
 
 pub struct MethodDef<'a> {
     /// name of the method
-    pub name: &'a str,
+    pub name: Symbol,
     /// List of generics, e.g., `R: rand::Rng`
     pub generics: LifetimeBounds<'a>,
 
@@ -681,7 +681,7 @@ impl<'a> TraitDef<'a> {
         let opt_trait_ref = Some(trait_ref);
         let unused_qual = {
             let word = rustc_ast::attr::mk_nested_word_item(Ident::new(
-                Symbol::intern("unused_qualifications"),
+                sym::unused_qualifications,
                 self.span,
             ));
             let list = rustc_ast::attr::mk_list_item(Ident::new(sym::allow, self.span), vec![word]);
@@ -818,7 +818,7 @@ impl<'a> MethodDef<'a> {
     ) -> P<Expr> {
         let substructure = Substructure {
             type_ident,
-            method_ident: cx.ident_of(self.name, trait_.span),
+            method_ident: Ident::new(self.name, trait_.span),
             self_args,
             nonself_args,
             fields,
@@ -913,7 +913,7 @@ impl<'a> MethodDef<'a> {
 
         let ret_type = self.get_ret_ty(cx, trait_, generics, type_ident);
 
-        let method_ident = cx.ident_of(self.name, trait_.span);
+        let method_ident = Ident::new(self.name, trait_.span);
         let fn_decl = cx.fn_decl(args, ast::FnRetTy::Ty(ret_type));
         let body_block = cx.block_expr(body);
 
@@ -1315,7 +1315,7 @@ impl<'a> MethodDef<'a> {
                 // Since we know that all the arguments will match if we reach
                 // the match expression we add the unreachable intrinsics as the
                 // result of the catch all which should help llvm in optimizing it
-                Some(deriving::call_intrinsic(cx, sp, "unreachable", vec![]))
+                Some(deriving::call_intrinsic(cx, sp, sym::unreachable, vec![]))
             }
             _ => None,
         };
@@ -1363,7 +1363,7 @@ impl<'a> MethodDef<'a> {
             for (&ident, self_arg) in vi_idents.iter().zip(&self_args) {
                 let self_addr = cx.expr_addr_of(sp, self_arg.clone());
                 let variant_value =
-                    deriving::call_intrinsic(cx, sp, "discriminant_value", vec![self_addr]);
+                    deriving::call_intrinsic(cx, sp, sym::discriminant_value, vec![self_addr]);
                 let let_stmt = cx.stmt_let(sp, false, ident, variant_value);
                 index_let_stmts.push(let_stmt);
 
@@ -1464,7 +1464,7 @@ impl<'a> MethodDef<'a> {
             // derive Debug on such a type could here generate code
             // that needs the feature gate enabled.)
 
-            deriving::call_intrinsic(cx, sp, "unreachable", vec![])
+            deriving::call_intrinsic(cx, sp, sym::unreachable, vec![])
         } else {
             // Final wrinkle: the self_args are expressions that deref
             // down to desired places, but we cannot actually deref

src/librustc_builtin_macros/deriving/hash.rs

@@ -29,7 +29,7 @@ pub fn expand_deriving_hash(
         is_unsafe: false,
         supports_unions: false,
         methods: vec![MethodDef {
-            name: "hash",
+            name: sym::hash,
             generics: LifetimeBounds {
                 lifetimes: Vec::new(),
                 bounds: vec![(typaram, vec![path_std!(cx, hash::Hasher)])],
@@ -73,7 +73,7 @@ fn hash_substructure(cx: &mut ExtCtxt<'_>, trait_span: Span, substr: &Substructu
             let variant_value = deriving::call_intrinsic(
                 cx,
                 trait_span,
-                "discriminant_value",
+                sym::discriminant_value,
                 vec![cx.expr_self(trait_span)],
             );
 

src/librustc_builtin_macros/deriving/mod.rs

@@ -62,11 +62,11 @@ impl MultiItemModifier for BuiltinDerive {
 fn call_intrinsic(
     cx: &ExtCtxt<'_>,
     span: Span,
-    intrinsic: &str,
+    intrinsic: Symbol,
     args: Vec<P<ast::Expr>>,
 ) -> P<ast::Expr> {
     let span = cx.with_def_site_ctxt(span);
-    let path = cx.std_path(&[sym::intrinsics, Symbol::intern(intrinsic)]);
+    let path = cx.std_path(&[sym::intrinsics, intrinsic]);
     let call = cx.expr_call_global(span, path, args);
 
     cx.expr_block(P(ast::Block {

src/librustc_builtin_macros/global_allocator.rs

@@ -79,12 +79,8 @@ impl AllocFnFactory<'_, '_> {
         self.cx.stmt_item(self.span, item)
     }
 
-    fn call_allocator(&self, method: &str, mut args: Vec<P<Expr>>) -> P<Expr> {
-        let method = self.cx.std_path(&[
-            Symbol::intern("alloc"),
-            Symbol::intern("GlobalAlloc"),
-            Symbol::intern(method),
-        ]);
+    fn call_allocator(&self, method: Symbol, mut args: Vec<P<Expr>>) -> P<Expr> {
+        let method = self.cx.std_path(&[sym::alloc, sym::GlobalAlloc, method]);
         let method = self.cx.expr_path(self.cx.path(self.span, method));
         let allocator = self.cx.path_ident(self.span, self.global);
         let allocator = self.cx.expr_path(allocator);
@@ -115,11 +111,8 @@ impl AllocFnFactory<'_, '_> {
                 args.push(self.cx.param(self.span, size, ty_usize.clone()));
                 args.push(self.cx.param(self.span, align, ty_usize));
 
-                let layout_new = self.cx.std_path(&[
-                    Symbol::intern("alloc"),
-                    Symbol::intern("Layout"),
-                    Symbol::intern("from_size_align_unchecked"),
-                ]);
+                let layout_new =
+                    self.cx.std_path(&[sym::alloc, sym::Layout, sym::from_size_align_unchecked]);
                 let layout_new = self.cx.expr_path(self.cx.path(self.span, layout_new));
                 let size = self.cx.expr_ident(self.span, size);
                 let align = self.cx.expr_ident(self.span, align);

src/librustc_builtin_macros/test_harness.rs

@@ -164,10 +164,8 @@ impl MutVisitor for EntryPointCleaner {
             EntryPointType::MainNamed | EntryPointType::MainAttr | EntryPointType::Start => item
                 .map(|ast::Item { id, ident, attrs, kind, vis, span, tokens }| {
                     let allow_ident = Ident::new(sym::allow, self.def_site);
-                    let dc_nested = attr::mk_nested_word_item(Ident::from_str_and_span(
-                        "dead_code",
-                        self.def_site,
-                    ));
+                    let dc_nested =
+                        attr::mk_nested_word_item(Ident::new(sym::dead_code, self.def_site));
                     let allow_dead_code_item = attr::mk_list_item(allow_ident, vec![dc_nested]);
                     let allow_dead_code = attr::mk_attr_outer(allow_dead_code_item);
                     let attrs = attrs