New Backend trait containing associated types

src/librustc_codegen_llvm/builder.rs

@@ -18,7 +18,7 @@
 use rustc::ty::layout::{Align, Size};
 use rustc::session::{config, Session};
 use rustc_data_structures::small_c_str::SmallCStr;
-use interfaces::BuilderMethods;
+use interfaces::{BuilderMethods, Backend};
 use syntax;
 
 use std::borrow::Cow;
@@ -55,11 +55,13 @@ pub struct MemFlags: u8 {
     }
 }
 
-impl BuilderMethods<'a, 'll, 'tcx> for Builder<'a, 'll, 'tcx> {
-    type Value = &'ll Value;
-    type BasicBlock = &'ll BasicBlock;
-    type Type = &'ll type_::Type;
+impl Backend for Builder<'a, 'll, 'tcx>  {
+        type Value = &'ll Value;
+        type BasicBlock = &'ll BasicBlock;
+        type Type = &'ll type_::Type;
+}
 
+impl BuilderMethods<'a, 'll, 'tcx> for Builder<'a, 'll, 'tcx> {
     fn new_block<'b>(
         cx: &'a CodegenCx<'ll, 'tcx>,
         llfn: &'ll Value,

src/librustc_codegen_llvm/interfaces/backend.rs

+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+pub trait Backend {
+    type Value;
+    type BasicBlock;
+    type Type;
+}

src/librustc_codegen_llvm/interfaces/builder.rs

@@ -14,6 +14,7 @@
 use rustc::ty::layout::{Align, Size};
 use rustc::session::Session;
 use builder::MemFlags;
+use super::backend::Backend;
 
 use std::borrow::Cow;
 use std::ops::Range;
@@ -21,10 +22,7 @@
 
 
 
-pub trait BuilderMethods<'a, 'll :'a, 'tcx: 'll> {
-    type Value;
-    type BasicBlock;
-    type Type;
+pub trait BuilderMethods<'a, 'll :'a, 'tcx: 'll> : Backend {
 
     fn new_block<'b>(
         cx: &'a CodegenCx<'ll, 'tcx, Self::Value>,

src/librustc_codegen_llvm/interfaces/mod.rs

@@ -9,5 +9,7 @@
 // except according to those terms.
 
 mod builder;
+mod backend;
 
 pub use self::builder::BuilderMethods;
+pub use self::backend::Backend;