refactor

Author: mati865

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -1418,13 +1418,16 @@ pub fn linker_and_flavor(sess: &Session, self_contained: bool) -> (PathBuf, Link
         return ret;
     }
 
-    // FIXME: do it better
-    if sess.target.os == "windows"
+    // When using a supported target in self-contained mode, we want to use rust-lld directly.
+    let self_contained_target = sess.target.os == "windows"
         && sess.target.env == "gnu"
         && sess.target.abi == "llvm"
-        && self_contained
+        && self_contained;
+    if self_contained_target
+        && let Some(ret) =
+            infer_from(sess, None, Some(LinkerFlavor::Gnu(Cc::No, Lld::Yes)), features)
     {
-        return (PathBuf::from("rust-lld.exe"), LinkerFlavor::Gnu(Cc::No, Lld::Yes));
+        return ret;
     }
 
     if let Some(ret) = infer_from(
@@ -1773,30 +1776,30 @@ fn link_output_kind(sess: &Session, crate_type: CrateType) -> LinkOutputKind {
     }
 }
 
-// Returns true if linker is located within sysroot
+/// Returns true if linker is shipped by Rust.
+// There are currently two different solutions for self-contained mode with mingw-w64:
+// using rust-lld directly (`-gnullvm`) or using shipped cc to call the linker (`-gnu`).
+// Eventually, `-gnu` toolchains might be moved to calling the linker directly.
 fn detect_self_contained_mingw(sess: &Session) -> bool {
-    // FIXME: this sort of duplicates `infer_from()` inside `linker_and_flavor()`
-    let path_buf = sess
-        .opts
-        .cg
-        .linker
-        .as_ref()
-        .map(|l| l.as_path())
-        .or_else(|| sess.target.linker.as_ref().map(|linker| Path::new(linker.as_ref())));
-    let linker = if let Some(linker) = path_buf {
-        linker
-    } else {
-        return false;
-    };
+    // Passing custom linker means non-self-contained mode.
+    if sess.opts.cg.linker.is_some() {
+        // Unless running on `-windows-gnu-llvm` and using `-C linker=rust-lld`.
+        if sess.target.abi == "llvm" {
+            return sess
+                .opts
+                .cg
+                .linker
+                .as_ref()
+                .is_some_and(|linker| linker == Path::new("rust-lld"));
+        }
 
-    // Assume `-C linker=rust-lld` as self-contained mode
-    if linker == Path::new("rust-lld") {
-        return true;
+        return false;
     }
-    let linker_with_extension = if cfg!(windows) && linker.extension().is_none() {
+
+    let linker_with_extension = if let Some(linker) = sess.target.linker.as_deref().map(Path::new) {
         linker.with_extension("exe")
     } else {
-        linker.to_path_buf()
+        return false;
     };
     for dir in env::split_paths(&env::var_os("PATH").unwrap_or_default()) {
         let full_path = dir.join(&linker_with_extension);