Change `SymbolName::name` to a `&str`.

This eliminates a bunch of `Symbol::intern()` and `Symbol::as_str()`
calls, which is good, because they require locking the interner.

Note that the unsafety in `from_cycle_error()` is identical to the
unsafety on other adjacent impls.

4 files changed, 14 insertions, 16 deletions

diff --git a/src/librustc_codegen_ssa/back/symbol_export.rs b/src/librustc_codegen_ssa/back/symbol_export.rs
index faf6809f35b..e0910c693b1 100644
--- a/src/librustc_codegen_ssa/back/symbol_export.rs
+++ b/src/librustc_codegen_ssa/back/symbol_export.rs
@@ -16,7 +16,6 @@ use rustc_middle::ty::subst::{GenericArgKind, SubstsRef};
 use rustc_middle::ty::Instance;
 use rustc_middle::ty::{SymbolName, TyCtxt};
 use rustc_session::config::{CrateType, SanitizerSet};
-use rustc_span::symbol::sym;
 
 pub fn threshold(tcx: TyCtxt<'_>) -> SymbolExportLevel {
     crates_export_threshold(&tcx.sess.crate_types())
@@ -117,9 +116,9 @@ fn reachable_non_generics_provider(tcx: TyCtxt<'_>, cnum: CrateNum) -> DefIdMap<
                 // In general though we won't link right if these
                 // symbols are stripped, and LTO currently strips them.
                 match name {
-                    sym::rust_eh_personality
-                    | sym::rust_eh_register_frames
-                    | sym::rust_eh_unregister_frames =>
+                    "rust_eh_personality"
+                    | "rust_eh_register_frames"
+                    | "rust_eh_unregister_frames" =>
                         SymbolExportLevel::C,
                     _ => SymbolExportLevel::Rust,
                 }
@@ -177,7 +176,7 @@ fn exported_symbols_provider_local(
         .collect();
 
     if tcx.entry_fn(LOCAL_CRATE).is_some() {
-        let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new("main"));
+        let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(tcx, "main"));
 
         symbols.push((exported_symbol, SymbolExportLevel::C));
     }
@@ -185,7 +184,7 @@ fn exported_symbols_provider_local(
     if tcx.allocator_kind().is_some() {
         for method in ALLOCATOR_METHODS {
             let symbol_name = format!("__rust_{}", method.name);
-            let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(&symbol_name));
+            let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(tcx, &symbol_name));
 
             symbols.push((exported_symbol, SymbolExportLevel::Rust));
         }
@@ -199,7 +198,7 @@ fn exported_symbols_provider_local(
             ["__llvm_profile_raw_version", "__llvm_profile_filename"];
 
         symbols.extend(PROFILER_WEAK_SYMBOLS.iter().map(|sym| {
-            let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(sym));
+            let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(tcx, sym));
             (exported_symbol, SymbolExportLevel::C)
         }));
     }
@@ -209,14 +208,14 @@ fn exported_symbols_provider_local(
         const MSAN_WEAK_SYMBOLS: [&str; 2] = ["__msan_track_origins", "__msan_keep_going"];
 
         symbols.extend(MSAN_WEAK_SYMBOLS.iter().map(|sym| {
-            let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(sym));
+            let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(tcx, sym));
             (exported_symbol, SymbolExportLevel::C)
         }));
     }
 
     if tcx.sess.crate_types().contains(&CrateType::Dylib) {
         let symbol_name = metadata_symbol_name(tcx);
-        let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(&symbol_name));
+        let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(tcx, &symbol_name));
 
         symbols.push((exported_symbol, SymbolExportLevel::Rust));
     }
diff --git a/src/librustc_codegen_ssa/mir/block.rs b/src/librustc_codegen_ssa/mir/block.rs
index 7116bb8c925..0ec46b515b4 100644
--- a/src/librustc_codegen_ssa/mir/block.rs
+++ b/src/librustc_codegen_ssa/mir/block.rs
@@ -16,7 +16,7 @@ use rustc_middle::mir;
 use rustc_middle::mir::interpret::{AllocId, ConstValue, Pointer, Scalar};
 use rustc_middle::mir::AssertKind;
 use rustc_middle::ty::layout::{FnAbiExt, HasTyCtxt};
-use rustc_middle::ty::{self, Instance, Ty, TypeFoldable};
+use rustc_middle::ty::{self, Instance, SymbolName, Ty, TypeFoldable};
 use rustc_span::source_map::Span;
 use rustc_span::{sym, Symbol};
 use rustc_target::abi::call::{ArgAbi, FnAbi, PassMode};
@@ -423,8 +423,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 (lang_items::PanicBoundsCheckFnLangItem, vec![index, len, location])
             }
             _ => {
-                let msg_str = Symbol::intern(msg.description());
-                let msg = bx.const_str(msg_str);
+                let msg = bx.const_str(SymbolName::new(bx.tcx(), msg.description()));
                 // It's `pub fn panic(expr: &str)`, with the wide reference being passed
                 // as two arguments, and `#[track_caller]` adds an implicit third argument.
                 (lang_items::PanicFnLangItem, vec![msg.0, msg.1, location])
@@ -487,7 +486,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 } else {
                     format!("attempted to leave type `{}` uninitialized, which is invalid", ty)
                 };
-                let msg = bx.const_str(Symbol::intern(&msg_str));
+                let msg = bx.const_str(SymbolName::new(bx.tcx(), &msg_str));
                 let location = self.get_caller_location(bx, span).immediate();
 
                 // Obtain the panic entry point.
diff --git a/src/librustc_codegen_ssa/mono_item.rs b/src/librustc_codegen_ssa/mono_item.rs
index 5994ef2be54..fc65149937f 100644
--- a/src/librustc_codegen_ssa/mono_item.rs
+++ b/src/librustc_codegen_ssa/mono_item.rs
@@ -64,7 +64,7 @@ impl<'a, 'tcx: 'a> MonoItemExt<'a, 'tcx> for MonoItem<'tcx> {
             cx.codegen_unit().name()
         );
 
-        let symbol_name = self.symbol_name(cx.tcx()).name.as_str();
+        let symbol_name = self.symbol_name(cx.tcx()).name;
 
         debug!("symbol {}", &symbol_name);
 
diff --git a/src/librustc_codegen_ssa/traits/consts.rs b/src/librustc_codegen_ssa/traits/consts.rs
index 6b58dea794b..e4c1e100626 100644
--- a/src/librustc_codegen_ssa/traits/consts.rs
+++ b/src/librustc_codegen_ssa/traits/consts.rs
@@ -2,7 +2,7 @@ use super::BackendTypes;
 use crate::mir::place::PlaceRef;
 use rustc_middle::mir::interpret::{Allocation, Scalar};
 use rustc_middle::ty::layout::TyAndLayout;
-use rustc_span::Symbol;
+use rustc_middle::ty::SymbolName;
 use rustc_target::abi::{self, Size};
 
 pub trait ConstMethods<'tcx>: BackendTypes {
@@ -20,7 +20,7 @@ pub trait ConstMethods<'tcx>: BackendTypes {
     fn const_u8(&self, i: u8) -> Self::Value;
     fn const_real(&self, t: Self::Type, val: f64) -> Self::Value;
 
-    fn const_str(&self, s: Symbol) -> (Self::Value, Self::Value);
+    fn const_str(&self, s: SymbolName<'tcx>) -> (Self::Value, Self::Value);
     fn const_struct(&self, elts: &[Self::Value], packed: bool) -> Self::Value;
 
     fn const_to_opt_uint(&self, v: Self::Value) -> Option<u64>;