Add a default implementation for CodegenBackend::link

As a side effect this should add raw-dylib support to cg_gcc as the
default ArchiveBuilderBuilder that is used implements
create_dll_import_lib. I haven't tested if the raw-dylib support
actually works however.

Author: bjorn3

src/archive.rs

@@ -58,7 +58,6 @@ extern crate rustc_driver;
 
 mod abi;
 mod allocator;
-mod archive;
 mod asm;
 mod attributes;
 mod back;
@@ -103,7 +102,7 @@ use rustc_codegen_ssa::traits::{CodegenBackend, ExtraBackendMethods, WriteBacken
 use rustc_codegen_ssa::{CodegenResults, CompiledModule, ModuleCodegen};
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::sync::IntoDynSyncSend;
-use rustc_errors::{DiagCtxtHandle, ErrorGuaranteed};
+use rustc_errors::DiagCtxtHandle;
 use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
 use rustc_middle::ty::TyCtxt;
@@ -261,17 +260,6 @@ impl CodegenBackend for GccCodegenBackend {
             .join(sess)
     }
 
-    fn link(
-        &self,
-        sess: &Session,
-        codegen_results: CodegenResults,
-        outputs: &OutputFilenames,
-    ) -> Result<(), ErrorGuaranteed> {
-        use rustc_codegen_ssa::back::link::link_binary;
-
-        link_binary(sess, &crate::archive::ArArchiveBuilderBuilder, &codegen_results, outputs)
-    }
-
     fn target_features(&self, sess: &Session, allow_unstable: bool) -> Vec<Symbol> {
         target_features(sess, allow_unstable, &self.target_info)
     }