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(),