diff --git a/compiler/rustc_ast/src/expand/allocator.rs b/compiler/rustc_ast/src/expand/allocator.rs
index c7ca66bc841..73e79d4441c 100644
--- a/compiler/rustc_ast/src/expand/allocator.rs
+++ b/compiler/rustc_ast/src/expand/allocator.rs
@@ -6,13 +6,12 @@ pub enum AllocatorKind {
     Default,
 }
 
-impl AllocatorKind {
-    pub fn fn_name(&self, base: Symbol) -> String {
-        match *self {
-            AllocatorKind::Global => format!("__rust_{base}"),
-            AllocatorKind::Default => format!("__rdl_{base}"),
-        }
-    }
+pub fn global_fn_name(base: Symbol) -> String {
+    format!("__rust_{base}")
+}
+
+pub fn default_fn_name(base: Symbol) -> String {
+    format!("__rdl_{base}")
 }
 
 pub fn alloc_error_handler_name(alloc_error_handler_kind: AllocatorKind) -> &'static str {
diff --git a/compiler/rustc_builtin_macros/src/global_allocator.rs b/compiler/rustc_builtin_macros/src/global_allocator.rs
index 1dd6a700e65..f0d378d12f7 100644
--- a/compiler/rustc_builtin_macros/src/global_allocator.rs
+++ b/compiler/rustc_builtin_macros/src/global_allocator.rs
@@ -1,7 +1,7 @@
 use crate::util::check_builtin_macro_attribute;
 
 use rustc_ast::expand::allocator::{
-    AllocatorKind, AllocatorMethod, AllocatorTy, ALLOCATOR_METHODS,
+    global_fn_name, AllocatorMethod, AllocatorTy, ALLOCATOR_METHODS,
 };
 use rustc_ast::ptr::P;
 use rustc_ast::{self as ast, AttrVec, Expr, FnHeader, FnSig, Generics, Param, StmtKind};
@@ -90,7 +90,7 @@ impl AllocFnFactory<'_, '_> {
         }));
         let item = self.cx.item(
             self.span,
-            Ident::from_str_and_span(&AllocatorKind::Global.fn_name(method.name), self.span),
+            Ident::from_str_and_span(&global_fn_name(method.name), self.span),
             self.attrs(),
             kind,
         );
diff --git a/compiler/rustc_codegen_cranelift/src/allocator.rs b/compiler/rustc_codegen_cranelift/src/allocator.rs
index ef69d3f7800..3b74050250b 100644
--- a/compiler/rustc_codegen_cranelift/src/allocator.rs
+++ b/compiler/rustc_codegen_cranelift/src/allocator.rs
@@ -4,7 +4,7 @@
 use crate::prelude::*;
 
 use rustc_ast::expand::allocator::{
-    alloc_error_handler_name, AllocatorKind, AllocatorTy, ALLOCATOR_METHODS,
+    alloc_error_handler_name, default_fn_name, AllocatorKind, AllocatorTy, ALLOCATOR_METHODS,
 };
 use rustc_codegen_ssa::base::allocator_kind_for_codegen;
 use rustc_session::config::OomStrategy;
@@ -69,7 +69,7 @@ fn codegen_inner(
                 unwind_context,
                 sig,
                 &format!("__rust_{}", method.name),
-                &AllocatorKind::Default.fn_name(method.name),
+                &default_fn_name(method.name),
             );
         }
     }
diff --git a/compiler/rustc_codegen_gcc/src/allocator.rs b/compiler/rustc_codegen_gcc/src/allocator.rs
index f4105b91e98..fe143aaad5f 100644
--- a/compiler/rustc_codegen_gcc/src/allocator.rs
+++ b/compiler/rustc_codegen_gcc/src/allocator.rs
@@ -2,7 +2,7 @@
 use gccjit::FnAttribute;
 use gccjit::{FunctionType, GlobalKind, ToRValue};
 use rustc_ast::expand::allocator::{
-    alloc_error_handler_name, AllocatorKind, AllocatorTy, ALLOCATOR_METHODS,
+    alloc_error_handler_name, default_fn_name, AllocatorKind, AllocatorTy, ALLOCATOR_METHODS,
 };
 use rustc_middle::bug;
 use rustc_middle::ty::TyCtxt;
@@ -61,7 +61,7 @@ pub(crate) unsafe fn codegen(tcx: TyCtxt<'_>, mods: &mut GccContext, _module_nam
                 // TODO(antoyo): emit unwind tables.
             }
 
-            let callee = AllocatorKind::Default.fn_name(method.name);
+            let callee = default_fn_name(method.name);
             let args: Vec<_> = types.iter().enumerate()
                 .map(|(index, typ)| context.new_parameter(None, *typ, &format!("param{}", index)))
                 .collect();
diff --git a/compiler/rustc_codegen_llvm/src/allocator.rs b/compiler/rustc_codegen_llvm/src/allocator.rs
index acf44f3276d..c2484681072 100644
--- a/compiler/rustc_codegen_llvm/src/allocator.rs
+++ b/compiler/rustc_codegen_llvm/src/allocator.rs
@@ -1,7 +1,7 @@
 use crate::attributes;
 use libc::c_uint;
 use rustc_ast::expand::allocator::{
-    alloc_error_handler_name, AllocatorKind, AllocatorTy, ALLOCATOR_METHODS,
+    alloc_error_handler_name, default_fn_name, AllocatorKind, AllocatorTy, ALLOCATOR_METHODS,
 };
 use rustc_middle::bug;
 use rustc_middle::ty::TyCtxt;
@@ -71,7 +71,7 @@ pub(crate) unsafe fn codegen(
                 attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &[uwtable]);
             }
 
-            let callee = AllocatorKind::Default.fn_name(method.name);
+            let callee = default_fn_name(method.name);
             let callee =
                 llvm::LLVMRustGetOrInsertFunction(llmod, callee.as_ptr().cast(), callee.len(), ty);
             llvm::LLVMRustSetVisibility(callee, llvm::Visibility::Hidden);
diff --git a/compiler/rustc_metadata/src/creader.rs b/compiler/rustc_metadata/src/creader.rs
index e6e7d25773e..07a9593fee8 100644
--- a/compiler/rustc_metadata/src/creader.rs
+++ b/compiler/rustc_metadata/src/creader.rs
@@ -4,7 +4,7 @@ use crate::errors;
 use crate::locator::{CrateError, CrateLocator, CratePaths};
 use crate::rmeta::{CrateDep, CrateMetadata, CrateNumMap, CrateRoot, MetadataBlob};
 
-use rustc_ast::expand::allocator::AllocatorKind;
+use rustc_ast::expand::allocator::{alloc_error_handler_name, global_fn_name, AllocatorKind};
 use rustc_ast::{self as ast, *};
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::svh::Svh;
@@ -1044,7 +1044,7 @@ fn global_allocator_spans(krate: &ast::Crate) -> Vec<Span> {
         }
     }
 
-    let name = Symbol::intern(&AllocatorKind::Global.fn_name(sym::alloc));
+    let name = Symbol::intern(&global_fn_name(sym::alloc));
     let mut f = Finder { name, spans: Vec::new() };
     visit::walk_crate(&mut f, krate);
     f.spans
@@ -1066,7 +1066,7 @@ fn alloc_error_handler_spans(krate: &ast::Crate) -> Vec<Span> {
         }
     }
 
-    let name = Symbol::intern(&AllocatorKind::Global.fn_name(sym::oom));
+    let name = Symbol::intern(alloc_error_handler_name(AllocatorKind::Global));
     let mut f = Finder { name, spans: Vec::new() };
     visit::walk_crate(&mut f, krate);
     f.spans