Merge HasCodegen into BuilderMethods.

It has `Backend` and `Deref` boudns, plus an associated type
`CodegenCx`, and it has a single use. This commit "inlines" it into
`BuilderMethods`, which makes the complicated backend trait situation a
little simpler.

compiler/rustc_codegen_gcc/src/builder.rs

@@ -14,8 +14,8 @@
 use rustc_codegen_ssa::mir::operand::{OperandRef, OperandValue};
 use rustc_codegen_ssa::mir::place::PlaceRef;
 use rustc_codegen_ssa::traits::{
-    BackendTypes, BaseTypeMethods, BuilderMethods, ConstMethods, HasCodegen, LayoutTypeMethods,
-    OverflowOp, StaticBuilderMethods,
+    BackendTypes, BaseTypeMethods, BuilderMethods, ConstMethods, LayoutTypeMethods, OverflowOp,
+    StaticBuilderMethods,
 };
 use rustc_codegen_ssa::MemFlags;
 use rustc_data_structures::fx::FxHashSet;
@@ -460,10 +460,6 @@ pub fn overflow_call(
     }
 }
 
-impl<'gcc, 'tcx> HasCodegen<'tcx> for Builder<'_, 'gcc, 'tcx> {
-    type CodegenCx = CodegenCx<'gcc, 'tcx>;
-}
-
 impl<'tcx> HasTyCtxt<'tcx> for Builder<'_, '_, 'tcx> {
     fn tcx(&self) -> TyCtxt<'tcx> {
         self.cx.tcx()
@@ -531,6 +527,8 @@ fn set_rvalue_location<'a, 'gcc, 'tcx>(
 }
 
 impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
+    type CodegenCx = CodegenCx<'gcc, 'tcx>;
+
     fn build(cx: &'a CodegenCx<'gcc, 'tcx>, block: Block<'gcc>) -> Builder<'a, 'gcc, 'tcx> {
         Builder::with_cx(cx, block)
     }

compiler/rustc_codegen_llvm/src/builder.rs

@@ -124,10 +124,6 @@ fn deref(&self) -> &Self::Target {
     }
 }
 
-impl<'ll, 'tcx> HasCodegen<'tcx> for Builder<'_, 'll, 'tcx> {
-    type CodegenCx = CodegenCx<'ll, 'tcx>;
-}
-
 macro_rules! builder_methods_for_value_instructions {
     ($($name:ident($($arg:ident),*) => $llvm_capi:ident),+ $(,)?) => {
         $(fn $name(&mut self, $($arg: &'ll Value),*) -> &'ll Value {
@@ -139,6 +135,8 @@ macro_rules! builder_methods_for_value_instructions {
 }
 
 impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
+    type CodegenCx = CodegenCx<'ll, 'tcx>;
+
     fn build(cx: &'a CodegenCx<'ll, 'tcx>, llbb: &'ll BasicBlock) -> Self {
         let bx = Builder::with_cx(cx);
         unsafe {

compiler/rustc_codegen_ssa/src/traits/builder.rs

@@ -1,4 +1,5 @@
 use std::assert_matches::assert_matches;
+use std::ops::Deref;
 
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs;
 use rustc_middle::ty::layout::{HasParamEnv, TyAndLayout};
@@ -17,7 +18,7 @@
 use super::intrinsic::IntrinsicCallMethods;
 use super::misc::MiscMethods;
 use super::type_::{ArgAbiMethods, BaseTypeMethods, LayoutTypeMethods};
-use super::{HasCodegen, StaticBuilderMethods};
+use super::{Backend, BackendTypes, CodegenMethods, StaticBuilderMethods};
 use crate::common::{
     AtomicOrdering, AtomicRmwBinOp, IntPredicate, RealPredicate, SynchronizationScope, TypeKind,
 };
@@ -33,7 +34,8 @@ pub enum OverflowOp {
 }
 
 pub trait BuilderMethods<'a, 'tcx>:
-    HasCodegen<'tcx>
+    Backend<'tcx>
+    + Deref<Target = Self::CodegenCx>
     + CoverageInfoBuilderMethods<'tcx>
     + DebugInfoBuilderMethods
     + ArgAbiMethods<'tcx>
@@ -44,6 +46,18 @@ pub trait BuilderMethods<'a, 'tcx>:
     + HasParamEnv<'tcx>
     + HasTargetSpec
 {
+    type CodegenCx: CodegenMethods<'tcx>
+        + BackendTypes<
+            Value = Self::Value,
+            Function = Self::Function,
+            BasicBlock = Self::BasicBlock,
+            Type = Self::Type,
+            Funclet = Self::Funclet,
+            DIScope = Self::DIScope,
+            DILocation = Self::DILocation,
+            DIVariable = Self::DIVariable,
+        >;
+
     fn build(cx: &'a Self::CodegenCx, llbb: Self::BasicBlock) -> Self;
 
     fn cx(&self) -> &Self::CodegenCx;

compiler/rustc_codegen_ssa/src/traits/mod.rs

@@ -63,19 +63,3 @@ pub trait CodegenMethods<'tcx> = Backend<'tcx>
     + HasParamEnv<'tcx>
     + HasTyCtxt<'tcx>
     + HasTargetSpec;
-
-pub trait HasCodegen<'tcx>:
-    Backend<'tcx> + std::ops::Deref<Target = <Self as HasCodegen<'tcx>>::CodegenCx>
-{
-    type CodegenCx: CodegenMethods<'tcx>
-        + BackendTypes<
-            Value = Self::Value,
-            Function = Self::Function,
-            BasicBlock = Self::BasicBlock,
-            Type = Self::Type,
-            Funclet = Self::Funclet,
-            DIScope = Self::DIScope,
-            DILocation = Self::DILocation,
-            DIVariable = Self::DIVariable,
-        >;
-}