Use () for codegen queries.

compiler/rustc_codegen_ssa/src/back/symbol_export.rs

@@ -230,7 +230,7 @@ fn exported_symbols_provider_local(
         // external linkage is enough for monomorphization to be linked to.
         let need_visibility = tcx.sess.target.dynamic_linking && !tcx.sess.target.only_cdylib;
 
-        let (_, cgus) = tcx.collect_and_partition_mono_items(LOCAL_CRATE);
+        let (_, cgus) = tcx.collect_and_partition_mono_items(());
 
         for (mono_item, &(linkage, visibility)) in cgus.iter().flat_map(|cgu| cgu.items().iter()) {
             if linkage != Linkage::External {
@@ -275,10 +275,8 @@ fn exported_symbols_provider_local(
 
 fn upstream_monomorphizations_provider(
     tcx: TyCtxt<'_>,
-    cnum: CrateNum,
+    (): (),
 ) -> DefIdMap<FxHashMap<SubstsRef<'_>, CrateNum>> {
-    debug_assert!(cnum == LOCAL_CRATE);
-
     let cnums = tcx.all_crate_nums(());
 
     let mut instances: DefIdMap<FxHashMap<_, _>> = Default::default();
@@ -341,7 +339,7 @@ fn upstream_monomorphizations_for_provider(
     def_id: DefId,
 ) -> Option<&FxHashMap<SubstsRef<'_>, CrateNum>> {
     debug_assert!(!def_id.is_local());
-    tcx.upstream_monomorphizations(LOCAL_CRATE).get(&def_id)
+    tcx.upstream_monomorphizations(()).get(&def_id)
 }
 
 fn upstream_drop_glue_for_provider<'tcx>(

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -482,7 +482,7 @@ pub fn start_async_codegen<B: ExtraBackendMethods>(
         codegen_worker_receive,
         shared_emitter_main,
         future: coordinator_thread,
-        output_filenames: tcx.output_filenames(LOCAL_CRATE),
+        output_filenames: tcx.output_filenames(()),
     }
 }
 
@@ -1042,7 +1042,7 @@ fn start_executing_work<B: ExtraBackendMethods>(
         // If we know that we won’t be doing codegen, create target machines without optimisation.
         config::OptLevel::No
     } else {
-        tcx.backend_optimization_level(LOCAL_CRATE)
+        tcx.backend_optimization_level(())
     };
     let cgcx = CodegenContext::<B> {
         backend: backend.clone(),
@@ -1061,7 +1061,7 @@ fn start_executing_work<B: ExtraBackendMethods>(
         cgu_reuse_tracker: sess.cgu_reuse_tracker.clone(),
         coordinator_send,
         diag_emitter: shared_emitter.clone(),
-        output_filenames: tcx.output_filenames(LOCAL_CRATE),
+        output_filenames: tcx.output_filenames(()),
         regular_module_config: regular_config,
         metadata_module_config: metadata_config,
         allocator_module_config: allocator_config,

compiler/rustc_codegen_ssa/src/base.rs

@@ -485,7 +485,7 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
 
     // Run the monomorphization collector and partition the collected items into
     // codegen units.
-    let codegen_units = tcx.collect_and_partition_mono_items(LOCAL_CRATE).1;
+    let codegen_units = tcx.collect_and_partition_mono_items(()).1;
 
     // Force all codegen_unit queries so they are already either red or green
     // when compile_codegen_unit accesses them. We are not able to re-execute