diff --git a/gcc/rust/Make-lang.in b/gcc/rust/Make-lang.in
index 7dad27a5dcd..a24025cb31c 100644
--- a/gcc/rust/Make-lang.in
+++ b/gcc/rust/Make-lang.in
@@ -156,6 +156,7 @@ GRS_OBJS = \
     rust/rust-imports.o \
     rust/rust-import-archive.o \
     rust/rust-extern-crate.o \
+    rust/rust-builtins.o \
     $(END)
 # removed object files from here
 
diff --git a/gcc/rust/backend/rust-builtins.cc b/gcc/rust/backend/rust-builtins.cc
new file mode 100644
index 00000000000..14dc037edac
--- /dev/null
+++ b/gcc/rust/backend/rust-builtins.cc
@@ -0,0 +1,143 @@
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include "rust-builtins.h"
+
+namespace Rust {
+namespace Compile {
+
+static const int builtin_const = 1 << 0;
+static const int builtin_noreturn = 1 << 1;
+static const int builtin_novops = 1 << 2;
+
+BuiltinsContext &
+BuiltinsContext::get ()
+{
+  static BuiltinsContext instance;
+  return instance;
+}
+
+bool
+BuiltinsContext::lookup_simple_builtin (const std::string &name, tree *builtin)
+{
+  auto it = rust_intrinsic_to_gcc_builtin.find (name);
+  if (it == rust_intrinsic_to_gcc_builtin.end ())
+    return false;
+
+  return lookup_gcc_builtin (it->second, builtin);
+}
+
+BuiltinsContext::BuiltinsContext () { setup (); }
+
+void
+BuiltinsContext::setup_overflow_fns ()
+{
+  tree overflow_type
+    = build_varargs_function_type_list (boolean_type_node, NULL_TREE);
+
+  define_builtin ("add_overflow", BUILT_IN_ADD_OVERFLOW,
+		  "__builtin_add_overflow", "add_overflow", overflow_type, 0);
+  define_builtin ("sub_overflow", BUILT_IN_SUB_OVERFLOW,
+		  "__builtin_sub_overflow", "sub_overflow", overflow_type, 0);
+  define_builtin ("mul_overflow", BUILT_IN_MUL_OVERFLOW,
+		  "__builtin_mul_overflow", "mul_overflow", overflow_type, 0);
+}
+
+void
+BuiltinsContext::setup_math_fns ()
+{
+  tree math_function_type_f32
+    = build_function_type_list (float_type_node, float_type_node, NULL_TREE);
+
+  define_builtin ("sinf32", BUILT_IN_SINF, "__builtin_sinf", "sinf",
+		  math_function_type_f32, builtin_const);
+  define_builtin ("sqrtf32", BUILT_IN_SQRTF, "__builtin_sqrtf", "sqrtf",
+		  math_function_type_f32, builtin_const);
+}
+
+void
+BuiltinsContext::setup ()
+{
+  setup_math_fns ();
+  setup_overflow_fns ();
+
+  define_builtin ("unreachable", BUILT_IN_UNREACHABLE, "__builtin_unreachable",
+		  NULL, build_function_type (void_type_node, void_list_node),
+		  builtin_const | builtin_noreturn);
+
+  define_builtin ("abort", BUILT_IN_ABORT, "__builtin_abort", "abort",
+		  build_function_type (void_type_node, void_list_node),
+		  builtin_const | builtin_noreturn);
+
+  define_builtin ("breakpoint", BUILT_IN_TRAP, "__builtin_trap", "breakpoint",
+		  build_function_type (void_type_node, void_list_node),
+		  builtin_const | builtin_noreturn);
+
+  define_builtin ("memcpy", BUILT_IN_MEMCPY, "__builtin_memcpy", "memcpy",
+		  build_function_type_list (build_pointer_type (void_type_node),
+					    build_pointer_type (void_type_node),
+					    build_pointer_type (void_type_node),
+					    size_type_node, NULL_TREE),
+		  0);
+}
+
+static void
+handle_flags (tree decl, int flags)
+{
+  if (flags & builtin_const)
+    TREE_READONLY (decl) = 1;
+  if (flags & builtin_noreturn)
+    TREE_READONLY (decl) = 1;
+  if (flags & builtin_novops)
+    DECL_IS_NOVOPS (decl) = 1;
+}
+
+void
+BuiltinsContext::define_builtin (const std::string rust_name,
+				 built_in_function bcode, const char *name,
+				 const char *libname, tree fntype, int flags)
+{
+  tree decl = add_builtin_function (name, fntype, bcode, BUILT_IN_NORMAL,
+				    libname, NULL_TREE);
+  handle_flags (decl, flags);
+  set_builtin_decl (bcode, decl, true);
+
+  this->builtin_functions_[name] = decl;
+  if (libname != NULL)
+    {
+      decl = add_builtin_function (libname, fntype, bcode, BUILT_IN_NORMAL,
+				   NULL, NULL_TREE);
+      handle_flags (decl, flags);
+
+      this->builtin_functions_[libname] = decl;
+    }
+
+  rust_intrinsic_to_gcc_builtin[rust_name] = name;
+}
+
+bool
+BuiltinsContext::lookup_gcc_builtin (const std::string &name, tree *builtin)
+{
+  auto it = builtin_functions_.find (name);
+  if (it == builtin_functions_.end ())
+    return false;
+
+  *builtin = it->second;
+  return true;
+}
+
+} // namespace Compile
+} // namespace Rust
diff --git a/gcc/rust/backend/rust-builtins.h b/gcc/rust/backend/rust-builtins.h
index 5cd84010723..e421fa43755 100644
--- a/gcc/rust/backend/rust-builtins.h
+++ b/gcc/rust/backend/rust-builtins.h
@@ -78,88 +78,18 @@ namespace Compile {
 class BuiltinsContext
 {
 public:
-  static BuiltinsContext &get ()
-  {
-    static BuiltinsContext instance;
-    return instance;
-  }
+  static BuiltinsContext &get ();
 
-  bool lookup_simple_builtin (const std::string &name, tree *builtin)
-  {
-    auto it = rust_intrinsic_to_gcc_builtin.find (name);
-    if (it == rust_intrinsic_to_gcc_builtin.end ())
-      return false;
-
-    return lookup_gcc_builtin (it->second, builtin);
-  }
+  bool lookup_simple_builtin (const std::string &name, tree *builtin);
 
 private:
-  static const int builtin_const = 1 << 0;
-  static const int builtin_noreturn = 1 << 1;
-  static const int builtin_novops = 1 << 2;
-
-  BuiltinsContext () { setup (); }
-
-  void setup_overflow_fns ()
-  {
-    tree overflow_type
-      = build_varargs_function_type_list (boolean_type_node, NULL_TREE);
-
-    define_builtin ("add_overflow", BUILT_IN_ADD_OVERFLOW,
-		    "__builtin_add_overflow", "add_overflow", overflow_type, 0);
-    define_builtin ("sub_overflow", BUILT_IN_SUB_OVERFLOW,
-		    "__builtin_sub_overflow", "sub_overflow", overflow_type, 0);
-    define_builtin ("mul_overflow", BUILT_IN_MUL_OVERFLOW,
-		    "__builtin_mul_overflow", "mul_overflow", overflow_type, 0);
-  }
-
-  void setup_math_fns ()
-  {
-    tree math_function_type_f32
-      = build_function_type_list (float_type_node, float_type_node, NULL_TREE);
-
-    define_builtin ("sinf32", BUILT_IN_SINF, "__builtin_sinf", "sinf",
-		    math_function_type_f32, builtin_const);
-    define_builtin ("sqrtf32", BUILT_IN_SQRTF, "__builtin_sqrtf", "sqrtf",
-		    math_function_type_f32, builtin_const);
-  }
-
-  void setup ()
-  {
-    setup_math_fns ();
-    setup_overflow_fns ();
-
-    define_builtin ("unreachable", BUILT_IN_UNREACHABLE,
-		    "__builtin_unreachable", NULL,
-		    build_function_type (void_type_node, void_list_node),
-		    builtin_const | builtin_noreturn);
-
-    define_builtin ("abort", BUILT_IN_ABORT, "__builtin_abort", "abort",
-		    build_function_type (void_type_node, void_list_node),
-		    builtin_const | builtin_noreturn);
-
-    define_builtin ("breakpoint", BUILT_IN_TRAP, "__builtin_trap", "breakpoint",
-		    build_function_type (void_type_node, void_list_node),
-		    builtin_const | builtin_noreturn);
-
-    define_builtin (
-      "memcpy", BUILT_IN_MEMCPY, "__builtin_memcpy", "memcpy",
-      build_function_type_list (build_pointer_type (void_type_node),
-				build_pointer_type (void_type_node),
-				build_pointer_type (void_type_node),
-				size_type_node, NULL_TREE),
-      0);
-  }
-
-  static void handle_flags (tree decl, int flags)
-  {
-    if (flags & builtin_const)
-      TREE_READONLY (decl) = 1;
-    if (flags & builtin_noreturn)
-      TREE_READONLY (decl) = 1;
-    if (flags & builtin_novops)
-      DECL_IS_NOVOPS (decl) = 1;
-  }
+  BuiltinsContext ();
+
+  void setup_overflow_fns ();
+
+  void setup_math_fns ();
+
+  void setup ();
 
   // Define a builtin function.  BCODE is the builtin function code
   // defined by builtins.def.  NAME is the name of the builtin function.
@@ -169,35 +99,9 @@ private:
   // NORETURN_P is true if the function has the noreturn attribute.
   void define_builtin (const std::string rust_name, built_in_function bcode,
 		       const char *name, const char *libname, tree fntype,
-		       int flags)
-  {
-    tree decl = add_builtin_function (name, fntype, bcode, BUILT_IN_NORMAL,
-				      libname, NULL_TREE);
-    handle_flags (decl, flags);
-    set_builtin_decl (bcode, decl, true);
-
-    this->builtin_functions_[name] = decl;
-    if (libname != NULL)
-      {
-	decl = add_builtin_function (libname, fntype, bcode, BUILT_IN_NORMAL,
-				     NULL, NULL_TREE);
-	handle_flags (decl, flags);
-
-	this->builtin_functions_[libname] = decl;
-      }
-
-    rust_intrinsic_to_gcc_builtin[rust_name] = name;
-  }
-
-  bool lookup_gcc_builtin (const std::string &name, tree *builtin)
-  {
-    auto it = builtin_functions_.find (name);
-    if (it == builtin_functions_.end ())
-      return false;
-
-    *builtin = it->second;
-    return true;
-  }
+		       int flags);
+
+  bool lookup_gcc_builtin (const std::string &name, tree *builtin);
 
   // A mapping of the GCC built-ins exposed to GCC Rust.
   std::map<std::string, tree> builtin_functions_;
