Remove thin_link_data method from ThinBufferMethods

It is only used within cg_llvm.

compiler/rustc_codegen_gcc/src/back/lto.rs

@@ -650,10 +650,6 @@ impl ThinBufferMethods for ThinBuffer {
     fn data(&self) -> &[u8] {
         &[]
     }
-
-    fn thin_link_data(&self) -> &[u8] {
-        unimplemented!();
-    }
 }
 
 pub struct ThinData; //(Arc<TempDir>);

compiler/rustc_codegen_llvm/src/back/lto.rs

@@ -698,6 +698,14 @@ pub(crate) unsafe fn from_raw_ptr(ptr: *mut llvm::ThinLTOBuffer) -> ThinBuffer {
         let mut ptr = NonNull::new(ptr).unwrap();
         ThinBuffer(unsafe { ptr.as_mut() })
     }
+
+    pub(crate) fn thin_link_data(&self) -> &[u8] {
+        unsafe {
+            let ptr = llvm::LLVMRustThinLTOBufferThinLinkDataPtr(self.0) as *const _;
+            let len = llvm::LLVMRustThinLTOBufferThinLinkDataLen(self.0);
+            slice::from_raw_parts(ptr, len)
+        }
+    }
 }
 
 impl ThinBufferMethods for ThinBuffer {
@@ -708,14 +716,6 @@ fn data(&self) -> &[u8] {
             slice::from_raw_parts(ptr, len)
         }
     }
-
-    fn thin_link_data(&self) -> &[u8] {
-        unsafe {
-            let ptr = llvm::LLVMRustThinLTOBufferThinLinkDataPtr(self.0) as *const _;
-            let len = llvm::LLVMRustThinLTOBufferThinLinkDataLen(self.0);
-            slice::from_raw_parts(ptr, len)
-        }
-    }
 }
 
 impl Drop for ThinBuffer {

compiler/rustc_codegen_ssa/src/traits/write.rs

@@ -59,7 +59,6 @@ fn prepare_thin(
 
 pub trait ThinBufferMethods: Send + Sync {
     fn data(&self) -> &[u8];
-    fn thin_link_data(&self) -> &[u8];
 }
 
 pub trait ModuleBufferMethods: Send + Sync {