Store defids instead of symbol names in the aliases list

compiler/rustc_codegen_llvm/src/mono_item.rs

@@ -10,7 +10,6 @@ use rustc_middle::mir::mono::Visibility;
 use rustc_middle::ty::layout::{FnAbiOf, HasTypingEnv, LayoutOf};
 use rustc_middle::ty::{self, Instance, TypeVisitableExt};
 use rustc_session::config::CrateType;
-use rustc_span::Symbol;
 use rustc_target::spec::{Arch, RelocModel};
 use tracing::debug;
 
@@ -92,17 +91,19 @@ impl<'tcx> PreDefineCodegenMethods<'tcx> for CodegenCx<'_, 'tcx> {
 }
 
 impl CodegenCx<'_, '_> {
-    fn add_aliases(&self, aliasee: &llvm::Value, aliases: &[(Symbol, Linkage, Visibility)]) {
+    fn add_aliases(&self, aliasee: &llvm::Value, aliases: &[(DefId, Linkage, Visibility)]) {
         let ty = self.get_type_of_global(aliasee);
 
         for (alias, linkage, visibility) in aliases {
+            let symbol_name = self.tcx.symbol_name(Instance::mono(self.tcx, *alias));
+
             tracing::debug!("ALIAS: {alias:?} {linkage:?} {visibility:?}");
             let lldecl = llvm::add_alias(
                 self.llmod,
                 ty,
                 AddressSpace::ZERO,
                 aliasee,
-                &CString::new(alias.as_str()).unwrap(),
+                &CString::new(symbol_name.name).unwrap(),
             );
 
             llvm::set_visibility(lldecl, base::visibility_to_llvm(*visibility));

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -13,10 +13,10 @@ use rustc_middle::middle::codegen_fn_attrs::{
 use rustc_middle::mir::mono::Visibility;
 use rustc_middle::query::Providers;
 use rustc_middle::span_bug;
-use rustc_middle::ty::{self as ty, Instance, TyCtxt};
+use rustc_middle::ty::{self as ty, TyCtxt};
 use rustc_session::lint;
 use rustc_session::parse::feature_err;
-use rustc_span::{Span, Symbol, sym};
+use rustc_span::{Span, sym};
 use rustc_target::spec::Os;
 
 use crate::errors;
@@ -291,8 +291,6 @@ fn process_builtin_attrs(
                         )
                         .expect("eii should have declaration macro with extern target attribute");
 
-                        let symbol_name = tcx.symbol_name(Instance::mono(tcx, extern_item));
-
                         // this is to prevent a bug where a single crate defines both the default and explicit implementation
                         // for an EII. In that case, both of them may be part of the same final object file. I'm not 100% sure
                         // what happens, either rustc deduplicates the symbol or llvm, or it's random/order-dependent.
@@ -310,7 +308,7 @@ fn process_builtin_attrs(
                         }
 
                         codegen_fn_attrs.foreign_item_symbol_aliases.push((
-                            Symbol::intern(symbol_name.name),
+                            extern_item,
                             if i.is_default { Linkage::LinkOnceAny } else { Linkage::External },
                             Visibility::Default,
                         ));

compiler/rustc_middle/src/middle/codegen_fn_attrs.rs

@@ -2,6 +2,7 @@ use std::borrow::Cow;
 
 use rustc_abi::Align;
 use rustc_hir::attrs::{InlineAttr, InstructionSetAttr, Linkage, OptimizeAttr, RtsanSetting};
+use rustc_hir::def_id::DefId;
 use rustc_macros::{HashStable, TyDecodable, TyEncodable};
 use rustc_span::Symbol;
 use rustc_target::spec::SanitizerSet;
@@ -72,7 +73,7 @@ pub struct CodegenFnAttrs {
     /// generate this function under its real name,
     /// but *also* under the same name as this foreign function so that the foreign function has an implementation.
     // FIXME: make "SymbolName<'tcx>"
-    pub foreign_item_symbol_aliases: Vec<(Symbol, Linkage, Visibility)>,
+    pub foreign_item_symbol_aliases: Vec<(DefId, Linkage, Visibility)>,
     /// The `#[link_ordinal = "..."]` attribute, indicating an ordinal an
     /// imported function has in the dynamic library. Note that this must not
     /// be set when `link_name` is set. This is for foreign items with the