Introduce ByteSymbol

compiler/rustc_ast/src/ast.rs

@@ -32,7 +32,7 @@ use rustc_data_structures::tagged_ptr::Tag;
 use rustc_macros::{Decodable, Encodable, HashStable_Generic};
 pub use rustc_span::AttrId;
 use rustc_span::source_map::{Spanned, respan};
-use rustc_span::{DUMMY_SP, ErrorGuaranteed, Ident, Span, Symbol, kw, sym};
+use rustc_span::{ByteSymbol, DUMMY_SP, ErrorGuaranteed, Ident, Span, Symbol, kw, sym};
 use thin_vec::{ThinVec, thin_vec};
 
 pub use crate::format::*;
@@ -1766,7 +1766,7 @@ pub enum ExprKind {
     /// Added for optimization purposes to avoid the need to escape
     /// large binary blobs - should always behave like [`ExprKind::Lit`]
     /// with a `ByteStr` literal.
-    IncludedBytes(Arc<[u8]>),
+    IncludedBytes(Arc<[u8]>), // njn: change to ByteSymbol?
 
     /// A `format_args!()` expression.
     FormatArgs(P<FormatArgs>),
@@ -2024,7 +2024,8 @@ impl YieldKind {
 }
 
 /// A literal in a meta item.
-#[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
+// njn: look for clones
+#[derive(Clone, Copy, Encodable, Decodable, Debug, HashStable_Generic)]
 pub struct MetaItemLit {
     /// The original literal as written in the source code.
     pub symbol: Symbol,
@@ -2087,16 +2088,17 @@ pub enum LitFloatType {
 /// deciding the `LitKind`. This means that float literals like `1f32` are
 /// classified by this type as `Float`. This is different to `token::LitKind`
 /// which does *not* consider the suffix.
-#[derive(Clone, Encodable, Decodable, Debug, Hash, Eq, PartialEq, HashStable_Generic)]
+#[derive(Clone, Copy, Encodable, Decodable, Debug, Hash, Eq, PartialEq, HashStable_Generic)]
+// njn: look for clones
 pub enum LitKind {
     /// A string literal (`"foo"`). The symbol is unescaped, and so may differ
     /// from the original token's symbol.
     Str(Symbol, StrStyle),
     /// A byte string (`b"foo"`). Not stored as a symbol because it might be
     /// non-utf8, and symbols only allow utf8 strings.
-    ByteStr(Arc<[u8]>, StrStyle),
+    ByteStr(ByteSymbol, StrStyle),
     /// A C String (`c"foo"`). Guaranteed to only have `\0` at the end.
-    CStr(Arc<[u8]>, StrStyle),
+    CStr(ByteSymbol, StrStyle),
     /// A byte char (`b'f'`).
     Byte(u8),
     /// A character literal (`'a'`).

compiler/rustc_ast/src/util/literal.rs

@@ -5,7 +5,7 @@ use std::{ascii, fmt, str};
 use rustc_literal_escaper::{
     MixedUnit, Mode, byte_from_char, unescape_byte, unescape_char, unescape_mixed, unescape_unicode,
 };
-use rustc_span::{Span, Symbol, kw, sym};
+use rustc_span::{ByteSymbol, Span, Symbol, kw, sym};
 use tracing::debug;
 
 use crate::ast::{self, LitKind, MetaItemLit, StrStyle};
@@ -117,13 +117,13 @@ impl LitKind {
                         assert!(!err.is_fatal(), "failed to unescape string literal")
                     }
                 });
-                LitKind::ByteStr(buf.into(), StrStyle::Cooked)
+                LitKind::ByteStr(ByteSymbol::intern(&buf), StrStyle::Cooked)
             }
             token::ByteStrRaw(n) => {
                 // Raw strings have no escapes so we can convert the symbol
                 // directly to a `Arc<u8>`.
                 let buf = symbol.as_str().to_owned().into_bytes();
-                LitKind::ByteStr(buf.into(), StrStyle::Raw(n))
+                LitKind::ByteStr(ByteSymbol::intern(&buf), StrStyle::Raw(n))
             }
             token::CStr => {
                 let s = symbol.as_str();
@@ -138,15 +138,15 @@ impl LitKind {
                     }
                 });
                 buf.push(0);
-                LitKind::CStr(buf.into(), StrStyle::Cooked)
+                LitKind::CStr(ByteSymbol::intern(&buf), StrStyle::Cooked)
             }
             token::CStrRaw(n) => {
                 // Raw strings have no escapes so we can convert the symbol
                 // directly to a `Arc<u8>` after appending the terminating NUL
                 // char.
                 let mut buf = symbol.as_str().to_owned().into_bytes();
                 buf.push(0);
-                LitKind::CStr(buf.into(), StrStyle::Raw(n))
+                LitKind::CStr(ByteSymbol::intern(&buf), StrStyle::Raw(n))
             }
             token::Err(guar) => LitKind::Err(guar),
         })
@@ -169,11 +169,11 @@ impl fmt::Display for LitKind {
                 string = sym
             )?,
             LitKind::ByteStr(ref bytes, StrStyle::Cooked) => {
-                write!(f, "b\"{}\"", escape_byte_str_symbol(bytes))?
+                write!(f, "b\"{}\"", escape_byte_str_symbol(bytes.as_byte_str()))?
             }
             LitKind::ByteStr(ref bytes, StrStyle::Raw(n)) => {
                 // Unwrap because raw byte string literals can only contain ASCII.
-                let symbol = str::from_utf8(bytes).unwrap();
+                let symbol = str::from_utf8(bytes.as_byte_str()).unwrap();
                 write!(
                     f,
                     "br{delim}\"{string}\"{delim}",
@@ -182,11 +182,11 @@ impl fmt::Display for LitKind {
                 )?;
             }
             LitKind::CStr(ref bytes, StrStyle::Cooked) => {
-                write!(f, "c\"{}\"", escape_byte_str_symbol(bytes))?
+                write!(f, "c\"{}\"", escape_byte_str_symbol(bytes.as_byte_str()))?
             }
             LitKind::CStr(ref bytes, StrStyle::Raw(n)) => {
                 // This can only be valid UTF-8.
-                let symbol = str::from_utf8(bytes).unwrap();
+                let symbol = str::from_utf8(bytes.as_byte_str()).unwrap();
                 write!(f, "cr{delim}\"{symbol}\"{delim}", delim = "#".repeat(n as usize),)?;
             }
             LitKind::Int(n, ty) => {

compiler/rustc_ast_lowering/src/expr.rs

@@ -13,7 +13,7 @@ use rustc_middle::span_bug;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::errors::report_lit_error;
 use rustc_span::source_map::{Spanned, respan};
-use rustc_span::{DUMMY_SP, DesugaringKind, Ident, Span, Symbol, sym};
+use rustc_span::{ByteSymbol, DUMMY_SP, DesugaringKind, Ident, Span, Symbol, sym};
 use thin_vec::{ThinVec, thin_vec};
 use visit::{Visitor, walk_expr};
 
@@ -146,10 +146,10 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 }
                 ExprKind::Lit(token_lit) => hir::ExprKind::Lit(self.lower_lit(token_lit, e.span)),
                 ExprKind::IncludedBytes(bytes) => {
-                    let lit = self.arena.alloc(respan(
+                    let lit = respan(
                         self.lower_span(e.span),
-                        LitKind::ByteStr(Arc::clone(bytes), StrStyle::Cooked),
-                    ));
+                        LitKind::ByteStr(ByteSymbol::intern(&bytes), StrStyle::Cooked),
+                    );
                     hir::ExprKind::Lit(lit)
                 }
                 ExprKind::Cast(expr, ty) => {
@@ -422,19 +422,15 @@ impl<'hir> LoweringContext<'_, 'hir> {
         })
     }
 
-    pub(crate) fn lower_lit(
-        &mut self,
-        token_lit: &token::Lit,
-        span: Span,
-    ) -> &'hir Spanned<LitKind> {
+    pub(crate) fn lower_lit(&mut self, token_lit: &token::Lit, span: Span) -> hir::Lit {
         let lit_kind = match LitKind::from_token_lit(*token_lit) {
             Ok(lit_kind) => lit_kind,
             Err(err) => {
                 let guar = report_lit_error(&self.tcx.sess.psess, err, *token_lit, span);
                 LitKind::Err(guar)
             }
         };
-        self.arena.alloc(respan(self.lower_span(span), lit_kind))
+        respan(self.lower_span(span), lit_kind)
     }
 
     fn lower_unop(&mut self, u: UnOp) -> hir::UnOp {
@@ -2140,10 +2136,10 @@ impl<'hir> LoweringContext<'_, 'hir> {
     }
 
     fn expr_uint(&mut self, sp: Span, ty: ast::UintTy, value: u128) -> hir::Expr<'hir> {
-        let lit = self.arena.alloc(hir::Lit {
+        let lit = hir::Lit {
             span: sp,
             node: ast::LitKind::Int(value.into(), ast::LitIntType::Unsigned(ty)),
-        });
+        };
         self.expr(sp, hir::ExprKind::Lit(lit))
     }
 
@@ -2160,9 +2156,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
     }
 
     pub(super) fn expr_str(&mut self, sp: Span, value: Symbol) -> hir::Expr<'hir> {
-        let lit = self
-            .arena
-            .alloc(hir::Lit { span: sp, node: ast::LitKind::Str(value, ast::StrStyle::Cooked) });
+        let lit = hir::Lit { span: sp, node: ast::LitKind::Str(value, ast::StrStyle::Cooked) };
         self.expr(sp, hir::ExprKind::Lit(lit))
     }
 

compiler/rustc_ast_lowering/src/pat.rs

@@ -7,7 +7,7 @@ use rustc_hir::def::{DefKind, Res};
 use rustc_hir::{self as hir, LangItem};
 use rustc_middle::span_bug;
 use rustc_span::source_map::{Spanned, respan};
-use rustc_span::{DesugaringKind, Ident, Span};
+use rustc_span::{ByteSymbol, DesugaringKind, Ident, Span};
 
 use super::errors::{
     ArbitraryExpressionInPattern, ExtraDoubleDot, MisplacedDoubleDot, SubTupleBinding,
@@ -390,19 +390,15 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         allow_paths: bool,
     ) -> &'hir hir::PatExpr<'hir> {
         let span = self.lower_span(expr.span);
-        let err = |guar| hir::PatExprKind::Lit {
-            lit: self.arena.alloc(respan(span, LitKind::Err(guar))),
-            negated: false,
-        };
+        let err =
+            |guar| hir::PatExprKind::Lit { lit: respan(span, LitKind::Err(guar)), negated: false };
         let kind = match &expr.kind {
             ExprKind::Lit(lit) => {
                 hir::PatExprKind::Lit { lit: self.lower_lit(lit, span), negated: false }
             }
             ExprKind::ConstBlock(c) => hir::PatExprKind::ConstBlock(self.lower_const_block(c)),
             ExprKind::IncludedBytes(bytes) => hir::PatExprKind::Lit {
-                lit: self
-                    .arena
-                    .alloc(respan(span, LitKind::ByteStr(Arc::clone(bytes), StrStyle::Cooked))),
+                lit: respan(span, LitKind::ByteStr(ByteSymbol::intern(bytes), StrStyle::Cooked)),
                 negated: false,
             },
             ExprKind::Err(guar) => err(*guar),

compiler/rustc_builtin_macros/src/concat_bytes.rs

@@ -158,7 +158,7 @@ pub(crate) fn expand_concat_bytes(
                     accumulator.push(val);
                 }
                 Ok(LitKind::ByteStr(ref bytes, _)) => {
-                    accumulator.extend_from_slice(bytes);
+                    accumulator.extend_from_slice(bytes.as_byte_str());
                 }
                 _ => {
                     guar.get_or_insert_with(|| invalid_type_err(cx, token_lit, e.span, false));

compiler/rustc_hir/src/arena.rs

@@ -9,7 +9,6 @@ macro_rules! arena_types {
             [] attribute: rustc_hir::Attribute,
             [] owner_info: rustc_hir::OwnerInfo<'tcx>,
             [] use_path: rustc_hir::UsePath<'tcx>,
-            [] lit: rustc_hir::Lit,
             [] macro_def: rustc_ast::MacroDef,
         ]);
     )

compiler/rustc_hir/src/hir.rs

@@ -1809,7 +1809,7 @@ pub struct PatExpr<'hir> {
 #[derive(Debug, Clone, Copy, HashStable_Generic)]
 pub enum PatExprKind<'hir> {
     Lit {
-        lit: &'hir Lit,
+        lit: Lit,
         // FIXME: move this into `Lit` and handle negated literal expressions
         // once instead of matching on unop neg expressions everywhere.
         negated: bool,
@@ -2722,7 +2722,7 @@ pub enum ExprKind<'hir> {
     /// A unary operation (e.g., `!x`, `*x`).
     Unary(UnOp, &'hir Expr<'hir>),
     /// A literal (e.g., `1`, `"foo"`).
-    Lit(&'hir Lit),
+    Lit(Lit),
     /// A cast (e.g., `foo as f64`).
     Cast(&'hir Expr<'hir>, &'hir Ty<'hir>),
     /// A type ascription (e.g., `x: Foo`). See RFC 3307.

compiler/rustc_hir/src/intravisit.rs

@@ -343,7 +343,7 @@ pub trait Visitor<'v>: Sized {
     fn visit_pat_expr(&mut self, expr: &'v PatExpr<'v>) -> Self::Result {
         walk_pat_expr(self, expr)
     }
-    fn visit_lit(&mut self, _hir_id: HirId, _lit: &'v Lit, _negated: bool) -> Self::Result {
+    fn visit_lit(&mut self, _hir_id: HirId, _lit: Lit, _negated: bool) -> Self::Result {
         Self::Result::output()
     }
     fn visit_anon_const(&mut self, c: &'v AnonConst) -> Self::Result {
@@ -768,7 +768,7 @@ pub fn walk_pat_field<'v, V: Visitor<'v>>(visitor: &mut V, field: &'v PatField<'
 pub fn walk_pat_expr<'v, V: Visitor<'v>>(visitor: &mut V, expr: &'v PatExpr<'v>) -> V::Result {
     try_visit!(visitor.visit_id(expr.hir_id));
     match &expr.kind {
-        PatExprKind::Lit { lit, negated } => visitor.visit_lit(expr.hir_id, lit, *negated),
+        PatExprKind::Lit { lit, negated } => visitor.visit_lit(expr.hir_id, *lit, *negated),
         PatExprKind::ConstBlock(c) => visitor.visit_inline_const(c),
         PatExprKind::Path(qpath) => visitor.visit_qpath(qpath, expr.hir_id, expr.span),
     }

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -2433,9 +2433,9 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         };
 
         let lit_input = match expr.kind {
-            hir::ExprKind::Lit(lit) => Some(LitToConstInput { lit: &lit.node, ty, neg: false }),
+            hir::ExprKind::Lit(lit) => Some(LitToConstInput { lit: lit.node, ty, neg: false }),
             hir::ExprKind::Unary(hir::UnOp::Neg, expr) => match expr.kind {
-                hir::ExprKind::Lit(lit) => Some(LitToConstInput { lit: &lit.node, ty, neg: true }),
+                hir::ExprKind::Lit(lit) => Some(LitToConstInput { lit: lit.node, ty, neg: true }),
                 _ => None,
             },
             _ => None,

compiler/rustc_hir_pretty/src/lib.rs

@@ -1480,7 +1480,7 @@ impl<'a> State<'a> {
                 self.print_expr_addr_of(k, m, expr);
             }
             hir::ExprKind::Lit(lit) => {
-                self.print_literal(lit);
+                self.print_literal(&lit);
             }
             hir::ExprKind::Cast(expr, ty) => {
                 self.print_expr_cond_paren(expr, expr.precedence() < ExprPrecedence::Cast);

compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs

@@ -1631,10 +1631,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         match lit.node {
             ast::LitKind::Str(..) => Ty::new_static_str(tcx),
+            // njn: why is this an array, not a slice?
             ast::LitKind::ByteStr(ref v, _) => Ty::new_imm_ref(
                 tcx,
                 tcx.lifetimes.re_static,
-                Ty::new_array(tcx, tcx.types.u8, v.len() as u64),
+                Ty::new_array(tcx, tcx.types.u8, v.as_byte_str().len() as u64),
             ),
             ast::LitKind::Byte(_) => tcx.types.u8,
             ast::LitKind::Char(_) => tcx.types.char,

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -1624,7 +1624,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 node: rustc_ast::LitKind::Int(lit, rustc_ast::LitIntType::Unsuffixed),
                 span,
             }) => {
-                let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(*span) else {
+                let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span) else {
                     return false;
                 };
                 if !(snippet.starts_with("0x") || snippet.starts_with("0X")) {
@@ -1683,7 +1683,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         // We have satisfied all requirements to provide a suggestion. Emit it.
         err.span_suggestion(
-            *span,
+            span,
             format!("if you meant to create a null pointer, use `{null_path_str}()`"),
             null_path_str + "()",
             Applicability::MachineApplicable,

compiler/rustc_lint/src/invalid_from_utf8.rs

@@ -108,8 +108,9 @@ impl<'tcx> LateLintPass<'tcx> for InvalidFromUtf8 {
             }
             match init.kind {
                 ExprKind::Lit(Spanned { node: lit, .. }) => {
+                    // njn: rename bytes as byte_sym, here and elsewhere
                     if let LitKind::ByteStr(bytes, _) = &lit
-                        && let Err(utf8_error) = std::str::from_utf8(bytes)
+                        && let Err(utf8_error) = std::str::from_utf8(bytes.as_byte_str())
                     {
                         lint(init.span, utf8_error);
                     }

compiler/rustc_lint/src/late.rs

@@ -152,7 +152,7 @@ impl<'tcx, T: LateLintPass<'tcx>> hir_visit::Visitor<'tcx> for LateContextAndPas
         hir_visit::walk_pat(self, p);
     }
 
-    fn visit_lit(&mut self, hir_id: HirId, lit: &'tcx hir::Lit, negated: bool) {
+    fn visit_lit(&mut self, hir_id: HirId, lit: hir::Lit, negated: bool) {
         lint_callback!(self, check_lit, hir_id, lit, negated);
     }
 

compiler/rustc_lint/src/passes.rs

@@ -23,7 +23,7 @@ macro_rules! late_lint_methods {
             fn check_stmt(a: &'tcx rustc_hir::Stmt<'tcx>);
             fn check_arm(a: &'tcx rustc_hir::Arm<'tcx>);
             fn check_pat(a: &'tcx rustc_hir::Pat<'tcx>);
-            fn check_lit(hir_id: rustc_hir::HirId, a: &'tcx rustc_hir::Lit, negated: bool);
+            fn check_lit(hir_id: rustc_hir::HirId, a: rustc_hir::Lit, negated: bool);
             fn check_expr(a: &'tcx rustc_hir::Expr<'tcx>);
             fn check_expr_post(a: &'tcx rustc_hir::Expr<'tcx>);
             fn check_ty(a: &'tcx rustc_hir::Ty<'tcx, rustc_hir::AmbigArg>);

compiler/rustc_lint/src/types.rs

@@ -548,18 +548,12 @@ fn lint_fn_pointer<'tcx>(
 }
 
 impl<'tcx> LateLintPass<'tcx> for TypeLimits {
-    fn check_lit(
-        &mut self,
-        cx: &LateContext<'tcx>,
-        hir_id: HirId,
-        lit: &'tcx hir::Lit,
-        negated: bool,
-    ) {
+    fn check_lit(&mut self, cx: &LateContext<'tcx>, hir_id: HirId, lit: hir::Lit, negated: bool) {
         if negated {
             self.negated_expr_id = Some(hir_id);
             self.negated_expr_span = Some(lit.span);
         }
-        lint_literal(cx, self, hir_id, lit.span, lit, negated);
+        lint_literal(cx, self, hir_id, lit.span, &lit, negated);
     }
 
     fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx hir::Expr<'tcx>) {