diff --git a/src/comp/back/abi.rs b/src/comp/back/abi.rs
index 078c1f3dc584..e494b3b58901 100644
--- a/src/comp/back/abi.rs
+++ b/src/comp/back/abi.rs
@@ -69,9 +69,6 @@ const int worst_case_glue_call_args = 7;
 
 const int n_native_glues = 8;
 
-const int abi_x86_rustboot_cdecl = 1;
-const int abi_x86_rustc_fastcall = 2;
-
 tag native_glue_type {
     ngt_rust;
     ngt_pure_rust;
diff --git a/src/comp/middle/trans.rs b/src/comp/middle/trans.rs
index 96e92aeb8521..fedb6a8095b0 100644
--- a/src/comp/middle/trans.rs
+++ b/src/comp/middle/trans.rs
@@ -509,8 +509,7 @@ fn T_crate(&type_names tn) -> TypeRef {
                           T_int(),      // size_t main_exit_task_glue
                           T_int(),      // int n_rust_syms
                           T_int(),      // int n_c_syms
-                          T_int(),      // int n_libs
-                          T_int()       // uintptr_t abi_tag
+                          T_int()       // int n_libs
                           ]);
     tn.associate(s, t);
     ret t;
@@ -7504,8 +7503,7 @@ fn create_crate_constant(ValueRef crate_ptr, @glue_fns glues) {
                      exit_task_glue_off,  // size_t main_exit_task_glue_off
                      C_null(T_int()),     // int n_rust_syms
                      C_null(T_int()),     // int n_c_syms
-                     C_null(T_int()),     // int n_libs
-                     C_int(abi::abi_x86_rustc_fastcall) // uintptr_t abi_tag
+                     C_null(T_int())      // int n_libs
                      ]);
 
     llvm::LLVMSetInitializer(crate_ptr, crate_val);
diff --git a/src/rt/rust_internal.h b/src/rt/rust_internal.h
index a1b9be9bf6f8..dcc2501d61a8 100644
--- a/src/rt/rust_internal.h
+++ b/src/rt/rust_internal.h
@@ -243,8 +243,6 @@ public:
     size_t n_c_syms;
     size_t n_libs;
 
-    uintptr_t abi_tag;
-
     // Crates are immutable, constructed by the compiler.
 
     uintptr_t get_image_base() const;