Add a leading dash to linker plugin arguments in the gcc codegen

compiler/rustc_codegen_cranelift/src/lib.rs

@@ -165,6 +165,10 @@ impl CodegenBackend for CraneliftCodegenBackend {
         ""
     }
 
+    fn name(&self) -> &'static str {
+        "cranelift"
+    }
+
     fn init(&self, sess: &Session) {
         use rustc_session::config::{InstrumentCoverage, Lto};
         match sess.lto() {

compiler/rustc_codegen_gcc/src/lib.rs

@@ -184,6 +184,10 @@ impl CodegenBackend for GccCodegenBackend {
         crate::DEFAULT_LOCALE_RESOURCE
     }
 
+    fn name(&self) -> &'static str {
+        "gcc"
+    }
+
     fn init(&self, _sess: &Session) {
         #[cfg(feature = "master")]
         {

compiler/rustc_codegen_llvm/src/lib.rs

@@ -231,6 +231,10 @@ impl CodegenBackend for LlvmCodegenBackend {
         crate::DEFAULT_LOCALE_RESOURCE
     }
 
+    fn name(&self) -> &'static str {
+        "llvm"
+    }
+
     fn init(&self, sess: &Session) {
         llvm_util::init(sess); // Make sure llvm is inited
     }
@@ -349,7 +353,14 @@ impl CodegenBackend for LlvmCodegenBackend {
 
         // Run the linker on any artifacts that resulted from the LLVM run.
         // This should produce either a finished executable or library.
-        link_binary(sess, &LlvmArchiveBuilderBuilder, codegen_results, metadata, outputs);
+        link_binary(
+            sess,
+            &LlvmArchiveBuilderBuilder,
+            codegen_results,
+            metadata,
+            outputs,
+            self.name(),
+        );
     }
 }
 

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -79,6 +79,7 @@ pub fn link_binary(
     codegen_results: CodegenResults,
     metadata: EncodedMetadata,
     outputs: &OutputFilenames,
+    codegen_backend: &'static str,
 ) {
     let _timer = sess.timer("link_binary");
     let output_metadata = sess.opts.output_types.contains_key(&OutputType::Metadata);
@@ -154,6 +155,7 @@ pub fn link_binary(
                         &codegen_results,
                         &metadata,
                         path.as_ref(),
+                        codegen_backend,
                     );
                 }
             }
@@ -680,6 +682,7 @@ fn link_natively(
     codegen_results: &CodegenResults,
     metadata: &EncodedMetadata,
     tmpdir: &Path,
+    codegen_backend: &'static str,
 ) {
     info!("preparing {:?} to {:?}", crate_type, out_filename);
     let (linker_path, flavor) = linker_and_flavor(sess);
@@ -705,6 +708,7 @@ fn link_natively(
         codegen_results,
         metadata,
         self_contained_components,
+        codegen_backend,
     );
 
     linker::disable_localization(&mut cmd);
@@ -2208,6 +2212,7 @@ fn linker_with_args(
     codegen_results: &CodegenResults,
     metadata: &EncodedMetadata,
     self_contained_components: LinkSelfContainedComponents,
+    codegen_backend: &'static str,
 ) -> Command {
     let self_contained_crt_objects = self_contained_components.is_crt_objects_enabled();
     let cmd = &mut *super::linker::get_linker(
@@ -2216,6 +2221,7 @@ fn linker_with_args(
         flavor,
         self_contained_components.are_any_components_enabled(),
         &codegen_results.crate_info.target_cpu,
+        codegen_backend,
     );
     let link_output_kind = link_output_kind(sess, crate_type);
 

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -52,6 +52,7 @@ pub(crate) fn get_linker<'a>(
     flavor: LinkerFlavor,
     self_contained: bool,
     target_cpu: &'a str,
+    codegen_backend: &'static str,
 ) -> Box<dyn Linker + 'a> {
     let msvc_tool = find_msvc_tools::find_tool(&sess.target.arch, "link.exe");
 
@@ -154,6 +155,7 @@ pub(crate) fn get_linker<'a>(
             is_ld: cc == Cc::No,
             is_gnu: flavor.is_gnu(),
             uses_lld: flavor.uses_lld(),
+            codegen_backend,
         }) as Box<dyn Linker>,
         LinkerFlavor::Msvc(..) => Box::new(MsvcLinker { cmd, sess }) as Box<dyn Linker>,
         LinkerFlavor::EmCc => Box::new(EmLinker { cmd, sess }) as Box<dyn Linker>,
@@ -367,6 +369,7 @@ struct GccLinker<'a> {
     is_ld: bool,
     is_gnu: bool,
     uses_lld: bool,
+    codegen_backend: &'static str,
 }
 
 impl<'a> GccLinker<'a> {
@@ -423,9 +426,15 @@ impl<'a> GccLinker<'a> {
         if let Some(path) = &self.sess.opts.unstable_opts.profile_sample_use {
             self.link_arg(&format!("-plugin-opt=sample-profile={}", path.display()));
         };
+        let prefix = if self.codegen_backend == "gcc" {
+            // The GCC linker plugin requires a leading dash.
+            "-"
+        } else {
+            ""
+        };
         self.link_args(&[
-            &format!("-plugin-opt={opt_level}"),
-            &format!("-plugin-opt=mcpu={}", self.target_cpu),
+            &format!("-plugin-opt={prefix}{opt_level}"),
+            &format!("-plugin-opt={prefix}mcpu={}", self.target_cpu),
         ]);
     }
 

compiler/rustc_codegen_ssa/src/traits/backend.rs

@@ -41,6 +41,8 @@ pub trait CodegenBackend {
     /// Called before `init` so that all other functions are able to emit translatable diagnostics.
     fn locale_resource(&self) -> &'static str;
 
+    fn name(&self) -> &'static str;
+
     fn init(&self, _sess: &Session) {}
 
     fn print(&self, _req: &PrintRequest, _out: &mut String, _sess: &Session) {}
@@ -96,7 +98,14 @@ pub trait CodegenBackend {
         metadata: EncodedMetadata,
         outputs: &OutputFilenames,
     ) {
-        link_binary(sess, &ArArchiveBuilderBuilder, codegen_results, metadata, outputs);
+        link_binary(
+            sess,
+            &ArArchiveBuilderBuilder,
+            codegen_results,
+            metadata,
+            outputs,
+            self.name(),
+        );
     }
 }
 

tests/ui-fulldeps/codegen-backend/auxiliary/the_backend.rs

@@ -33,6 +33,10 @@ impl CodegenBackend for TheBackend {
         ""
     }
 
+    fn name(&self) -> &'static str {
+        "the-backend"
+    }
+
     fn codegen_crate(&self, tcx: TyCtxt<'_>) -> Box<dyn Any> {
         Box::new(CodegenResults {
             modules: vec![],