Remove inherent methods from `llvm::TypeKind`

compiler/rustc_codegen_llvm/src/llvm/conversions.rs

diff --git a/compiler/rustc_codegen_llvm/src/llvm/conversions.rs b/compiler/rustc_codegen_llvm/src/llvm/conversions.rs
index 9e9f9339..3bc790c 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/conversions.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/conversions.rs
@@ -1,6 +1,6 @@
 //! Conversions from backend-independent data types to/from LLVM FFI types.
 
-use rustc_codegen_ssa::common::{AtomicRmwBinOp, IntPredicate, RealPredicate};
+use rustc_codegen_ssa::common::{AtomicRmwBinOp, IntPredicate, RealPredicate, TypeKind};
 use rustc_middle::ty::AtomicOrdering;
 use rustc_session::config::DebugInfo;
 use rustc_target::spec::SymbolVisibility;
@@ -9,10 +9,22 @@
 
 /// Helper trait for converting backend-independent types to LLVM-specific
 /// types, for FFI purposes.
+///
+/// FIXME(#147327): These trait/method names were chosen to avoid churn in
+/// existing code, but are not great and could probably be made clearer.
 pub(crate) trait FromGeneric<T> {
     fn from_generic(other: T) -> Self;
 }
 
+/// Helper trait for converting LLVM-specific types to backend-independent
+/// types, for FFI purposes.
+///
+/// FIXME(#147327): These trait/method names were chosen to avoid churn in
+/// existing code, but are not great and could probably be made clearer.
+pub(crate) trait ToGeneric<T> {
+    fn to_generic(&self) -> T;
+}
+
 impl FromGeneric<SymbolVisibility> for llvm::Visibility {
     fn from_generic(visibility: SymbolVisibility) -> Self {
         match visibility {
@@ -113,3 +125,29 @@ fn from_generic(kind: DebugInfo) -> Self {
         }
     }
 }
+
+impl ToGeneric<TypeKind> for llvm::TypeKind {
+    fn to_generic(&self) -> TypeKind {
+        match self {
+            Self::Void => TypeKind::Void,
+            Self::Half => TypeKind::Half,
+            Self::Float => TypeKind::Float,
+            Self::Double => TypeKind::Double,
+            Self::X86_FP80 => TypeKind::X86_FP80,
+            Self::FP128 => TypeKind::FP128,
+            Self::PPC_FP128 => TypeKind::PPC_FP128,
+            Self::Label => TypeKind::Label,
+            Self::Integer => TypeKind::Integer,
+            Self::Function => TypeKind::Function,
+            Self::Struct => TypeKind::Struct,
+            Self::Array => TypeKind::Array,
+            Self::Pointer => TypeKind::Pointer,
+            Self::Vector => TypeKind::Vector,
+            Self::Metadata => TypeKind::Metadata,
+            Self::Token => TypeKind::Token,
+            Self::ScalableVector => TypeKind::ScalableVector,
+            Self::BFloat => TypeKind::BFloat,
+            Self::X86_AMX => TypeKind::X86_AMX,
+        }
+    }
+}

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index 2f53a19..10cb939 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -363,33 +363,6 @@ pub(crate) enum TypeKind {
     X86_AMX = 19,
 }
 
-impl TypeKind {
-    pub(crate) fn to_generic(self) -> rustc_codegen_ssa::common::TypeKind {
-        use rustc_codegen_ssa::common::TypeKind as Common;
-        match self {
-            Self::Void => Common::Void,
-            Self::Half => Common::Half,
-            Self::Float => Common::Float,
-            Self::Double => Common::Double,
-            Self::X86_FP80 => Common::X86_FP80,
-            Self::FP128 => Common::FP128,
-            Self::PPC_FP128 => Common::PPC_FP128,
-            Self::Label => Common::Label,
-            Self::Integer => Common::Integer,
-            Self::Function => Common::Function,
-            Self::Struct => Common::Struct,
-            Self::Array => Common::Array,
-            Self::Pointer => Common::Pointer,
-            Self::Vector => Common::Vector,
-            Self::Metadata => Common::Metadata,
-            Self::Token => Common::Token,
-            Self::ScalableVector => Common::ScalableVector,
-            Self::BFloat => Common::BFloat,
-            Self::X86_AMX => Common::X86_AMX,
-        }
-    }
-}
-
 /// LLVMAtomicRmwBinOp
 #[derive(Copy, Clone)]
 #[repr(C)]

compiler/rustc_codegen_llvm/src/type_.rs

diff --git a/compiler/rustc_codegen_llvm/src/type_.rs b/compiler/rustc_codegen_llvm/src/type_.rs
index 83d7fa0..d8b7736 100644
--- a/compiler/rustc_codegen_llvm/src/type_.rs
+++ b/compiler/rustc_codegen_llvm/src/type_.rs
@@ -15,7 +15,7 @@
 use crate::abi::{FnAbiLlvmExt, LlvmType};
 use crate::common;
 use crate::context::{CodegenCx, GenericCx, SCx};
-use crate::llvm::{self, FALSE, Metadata, TRUE, ToLlvmBool, Type, Value};
+use crate::llvm::{self, FALSE, Metadata, TRUE, ToGeneric, ToLlvmBool, Type, Value};
 use crate::type_of::LayoutLlvmExt;
 
 impl PartialEq for Type {