fix(ld64.lld): route version mismatch warnings to linker_info on macOS

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -884,9 +884,9 @@ fn is_msvc_link_exe(sess: &Session) -> bool {
         && linker_path.to_str() == Some("link.exe")
 }
 
-fn is_macos_ld(sess: &Session) -> bool {
+fn is_macos_linker(sess: &Session) -> bool {
     let (_, flavor) = linker_and_flavor(sess);
-    sess.target.is_like_darwin && matches!(flavor, LinkerFlavor::Darwin(_, Lld::No))
+    sess.target.is_like_darwin && matches!(flavor, LinkerFlavor::Darwin(..))
 }
 
 fn is_windows_gnu_ld(sess: &Session) -> bool {
@@ -953,8 +953,8 @@ fn report_linker_output(
                 *output += "\r\n"
             }
         });
-    } else if is_macos_ld(sess) {
-        info!("inferred macOS LD");
+    } else if is_macos_linker(sess) {
+        info!("inferred macOS linker");
 
         // FIXME: Tracked by https://github.com/rust-lang/rust/issues/136113
         let deployment_mismatch = |line: &str| {
@@ -967,6 +967,8 @@ fn report_linker_output(
                 && line.contains("building for")
                 && line.contains("but linking with")
                 && line.contains("which was built for newer version"))
+            // lld (ld64.lld / rust-lld):
+            || line.contains("which is newer than target minimum of")
         };
         // FIXME: This is a real warning we would like to show, but it hits too many crates
         // to want to turn it on immediately.

tests/run-make/macos-deployment-target-warning/rmake.rs

@@ -13,6 +13,7 @@ fn main() {
     let ld_prime_obj = r"ld: warning: object file \(.*\) was built for newer '.+' version \(\d+\.\d+\) than being linked \(\d+\.\d+\)";
     let ld64_dylib = r"ld: warning: dylib \(.*\) was built for newer .+ version \(\d+\.\d+\) than being linked \(\d+\.\d+\)";
     let ld_prime_dylib = r"ld: warning: building for [^ ,]+, but linking with dylib '[^']*' which was built for newer version [0-9.]+";
+    let lld_obj = r"ld64\.lld: warning: .+ has version \d+\.\d+(\.\d+)?, which is newer than target minimum of \d+\.\d+(\.\d+)?";
 
     // Test 1: static archive (object file mismatch)
     cc().arg("-c").arg("-mmacosx-version-min=15.5").output("foo.o").input("foo.c").run();
@@ -54,4 +55,26 @@ fn main() {
         .normalize(ld64_dylib, "NORMALIZED_DYLIB_DEPLOYMENT_MISMATCH_LINKER_WARNING")
         .normalize(ld_prime_dylib, "NORMALIZED_DYLIB_DEPLOYMENT_MISMATCH_LINKER_WARNING")
         .run();
+
+    // Test 3: static archive with lld (object file mismatch)
+    let lld_path = std::path::PathBuf::from(std::env::var("LLVM_BIN_DIR").unwrap()).join("lld");
+    let ld64_lld = std::env::current_dir().unwrap().join("ld64.lld");
+    std::os::unix::fs::symlink(&lld_path, &ld64_lld).expect("failed to create ld64.lld symlink");
+
+    let lld_warnings = rustc()
+        .arg("-lstatic=foo")
+        .arg("-Clink-self-contained=-linker")
+        .arg("-Zunstable-options")
+        .arg("-Clinker-flavor=darwin-lld")
+        .linker(&ld64_lld.to_str().unwrap())
+        .input("main.rs")
+        .crate_type("bin")
+        .run()
+        .stderr_utf8();
+
+    diff()
+        .expected_file("warnings.txt")
+        .actual_text("(rustc -W linker-info with lld)", &lld_warnings)
+        .normalize(lld_obj, "NORMALIZED_OBJECT_DEPLOYMENT_MISMATCH_LINKER_WARNING")
+        .run();
 }