linker: Report linker flavors incompatible with the current target

Previously they would be reported as link time errors about unknown linker options

2 files changed, 15 insertions, 0 deletions

diff --git a/compiler/rustc_session/src/errors.rs b/compiler/rustc_session/src/errors.rs
index 546c0fa8e03..4a3e668da11 100644
--- a/compiler/rustc_session/src/errors.rs
+++ b/compiler/rustc_session/src/errors.rs
@@ -422,3 +422,11 @@ pub fn report_lit_error(sess: &ParseSess, err: LitError, lit: token::Lit, span:
 pub struct OptimisationFuelExhausted {
     pub msg: String,
 }
+
+#[derive(Diagnostic)]
+#[diag(session_incompatible_linker_flavor)]
+#[note]
+pub struct IncompatibleLinkerFlavor {
+    pub flavor: &'static str,
+    pub compatible_list: String,
+}
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index bbe52dbced0..1eb54cee5a1 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -1675,6 +1675,13 @@ fn validate_commandline_args_with_session_available(sess: &Session) {
     if sess.opts.unstable_opts.instrument_xray.is_some() && !sess.target.options.supports_xray {
         sess.emit_err(errors::InstrumentationNotSupported { us: "XRay".to_string() });
     }
+
+    if let Some(flavor) = sess.opts.cg.linker_flavor {
+        if let Some(compatible_list) = sess.target.linker_flavor.check_compatibility(flavor) {
+            let flavor = flavor.desc();
+            sess.emit_err(errors::IncompatibleLinkerFlavor { flavor, compatible_list });
+        }
+    }
 }
 
 /// Holds data on the current incremental compilation session, if there is one.