Let LtoModuleCodegen::optimize take self by value

compiler/rustc_codegen_ssa/src/back/lto.rs

@@ -42,7 +42,7 @@ pub struct ThinShared<B: WriteBackendMethods> {
 
 pub enum LtoModuleCodegen<B: WriteBackendMethods> {
     Fat {
-        module: Option<ModuleCodegen<B::Module>>,
+        module: ModuleCodegen<B::Module>,
         _serialized_bitcode: Vec<SerializedModule<B::ModuleBuffer>>,
     },
 
@@ -64,19 +64,18 @@ impl<B: WriteBackendMethods> LtoModuleCodegen<B> {
     /// It's intended that the module returned is immediately code generated and
     /// dropped, and then this LTO module is dropped.
     pub unsafe fn optimize(
-        &mut self,
+        self,
         cgcx: &CodegenContext<B>,
     ) -> Result<ModuleCodegen<B::Module>, FatalError> {
-        match *self {
-            LtoModuleCodegen::Fat { ref mut module, .. } => {
-                let module = module.take().unwrap();
+        match self {
+            LtoModuleCodegen::Fat { module, .. } => {
                 {
                     let config = cgcx.config(module.kind);
-                    B::run_lto_pass_manager(cgcx, &module, config, false)?;
+                    B::optimize_fat(cgcx, &module, config)?;
                 }
                 Ok(module)
             }
-            LtoModuleCodegen::Thin(ref mut thin) => B::optimize_thin(cgcx, thin),
+            LtoModuleCodegen::Thin(thin) => B::optimize_thin(cgcx, thin),
         }
     }
 

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -889,7 +889,7 @@ fn execute_copy_from_cache_work_item<B: ExtraBackendMethods>(
 
 fn execute_lto_work_item<B: ExtraBackendMethods>(
     cgcx: &CodegenContext<B>,
-    mut module: lto::LtoModuleCodegen<B>,
+    module: lto::LtoModuleCodegen<B>,
     module_config: &ModuleConfig,
 ) -> Result<WorkItemResult<B>, FatalError> {
     let module = unsafe { module.optimize(cgcx)? };