linker: Make argument building interface in trait Linker richer

by redirecting everything to `Command`

src/librustc_codegen_ssa/back/link.rs

@@ -787,7 +787,7 @@ fn link_sanitizer_runtime(sess: &Session, crate_type: config::CrateType, linker:
             // PR #41352 for details).
             let libname = format!("rustc{}_rt.{}", channel, name);
             let rpath = default_tlib.to_str().expect("non-utf8 component in path");
-            linker.args(&["-Wl,-rpath".into(), "-Xlinker".into(), rpath.into()]);
+            linker.args(&["-Wl,-rpath", "-Xlinker", rpath]);
             linker.link_dylib(Symbol::intern(&libname));
         }
         "x86_64-unknown-linux-gnu" | "x86_64-fuchsia" | "aarch64-fuchsia" => {
@@ -1300,8 +1300,7 @@ fn link_args<'a, B: ArchiveBuilder<'a>>(
     }
 
     let attr_link_args = codegen_results.crate_info.link_args.iter();
-    let user_link_args: Vec<_> =
-        sess.opts.cg.link_args.iter().chain(attr_link_args).cloned().collect();
+    let user_link_args = sess.opts.cg.link_args.iter().chain(attr_link_args);
 
     if crate_type == config::CrateType::Executable {
         let mut position_independent_executable = false;
@@ -1309,7 +1308,7 @@ fn link_args<'a, B: ArchiveBuilder<'a>>(
         if t.options.position_independent_executables {
             if is_pic(sess)
                 && !sess.crt_static(Some(crate_type))
-                && !user_link_args.iter().any(|x| x == "-static")
+                && !user_link_args.clone().any(|x| x == "-static")
             {
                 position_independent_executable = true;
             }
@@ -1440,7 +1439,7 @@ fn link_args<'a, B: ArchiveBuilder<'a>>(
 
     // Finally add all the linker arguments provided on the command line along
     // with any #[link_args] attributes found inside the crate
-    cmd.args(&user_link_args);
+    cmd.args(user_link_args);
 }
 
 // # Native library linking

src/librustc_codegen_ssa/back/linker.rs

@@ -87,6 +87,7 @@ impl LinkerInfo {
 /// used to dispatch on whether a GNU-like linker (generally `ld.exe`) or an
 /// MSVC linker (e.g., `link.exe`) is being used.
 pub trait Linker {
+    fn cmd(&mut self) -> &mut Command;
     fn link_dylib(&mut self, lib: Symbol);
     fn link_rust_dylib(&mut self, lib: Symbol, path: &Path);
     fn link_framework(&mut self, framework: Symbol);
@@ -111,7 +112,6 @@ pub trait Linker {
     fn no_default_libraries(&mut self);
     fn build_dylib(&mut self, out_filename: &Path);
     fn build_static_executable(&mut self);
-    fn args(&mut self, args: &[String]);
     fn export_symbols(&mut self, tmpdir: &Path, crate_type: CrateType);
     fn subsystem(&mut self, subsystem: &str);
     fn group_start(&mut self);
@@ -121,6 +121,16 @@ pub trait Linker {
     fn finalize(&mut self) -> Command;
 }
 
+impl dyn Linker + '_ {
+    pub fn arg(&mut self, arg: impl AsRef<OsStr>) {
+        self.cmd().arg(arg);
+    }
+
+    pub fn args(&mut self, args: impl IntoIterator<Item: AsRef<OsStr>>) {
+        self.cmd().args(args);
+    }
+}
+
 pub struct GccLinker<'a> {
     cmd: Command,
     sess: &'a Session,
@@ -208,6 +218,9 @@ impl<'a> GccLinker<'a> {
 }
 
 impl<'a> Linker for GccLinker<'a> {
+    fn cmd(&mut self) -> &mut Command {
+        &mut self.cmd
+    }
     fn link_dylib(&mut self, lib: Symbol) {
         self.hint_dynamic();
         self.cmd.arg(format!("-l{}", lib));
@@ -251,9 +264,6 @@ impl<'a> Linker for GccLinker<'a> {
     fn build_static_executable(&mut self) {
         self.cmd.arg("-static");
     }
-    fn args(&mut self, args: &[String]) {
-        self.cmd.args(args);
-    }
 
     fn link_rust_dylib(&mut self, lib: Symbol, _path: &Path) {
         self.hint_dynamic();
@@ -545,15 +555,15 @@ pub struct MsvcLinker<'a> {
 }
 
 impl<'a> Linker for MsvcLinker<'a> {
+    fn cmd(&mut self) -> &mut Command {
+        &mut self.cmd
+    }
     fn link_rlib(&mut self, lib: &Path) {
         self.cmd.arg(lib);
     }
     fn add_object(&mut self, path: &Path) {
         self.cmd.arg(path);
     }
-    fn args(&mut self, args: &[String]) {
-        self.cmd.args(args);
-    }
 
     fn build_dylib(&mut self, out_filename: &Path) {
         self.cmd.arg("/DLL");
@@ -778,6 +788,9 @@ pub struct EmLinker<'a> {
 }
 
 impl<'a> Linker for EmLinker<'a> {
+    fn cmd(&mut self) -> &mut Command {
+        &mut self.cmd
+    }
     fn include_path(&mut self, path: &Path) {
         self.cmd.arg("-L").arg(path);
     }
@@ -837,10 +850,6 @@ impl<'a> Linker for EmLinker<'a> {
         // noop
     }
 
-    fn args(&mut self, args: &[String]) {
-        self.cmd.args(args);
-    }
-
     fn framework_path(&mut self, _path: &Path) {
         bug!("frameworks are not supported on Emscripten")
     }
@@ -992,6 +1001,10 @@ impl<'a> WasmLd<'a> {
 }
 
 impl<'a> Linker for WasmLd<'a> {
+    fn cmd(&mut self) -> &mut Command {
+        &mut self.cmd
+    }
+
     fn link_dylib(&mut self, lib: Symbol) {
         self.cmd.arg("-l").sym_arg(lib);
     }
@@ -1030,10 +1043,6 @@ impl<'a> Linker for WasmLd<'a> {
 
     fn build_static_executable(&mut self) {}
 
-    fn args(&mut self, args: &[String]) {
-        self.cmd.args(args);
-    }
-
     fn link_rust_dylib(&mut self, lib: Symbol, _path: &Path) {
         self.cmd.arg("-l").sym_arg(lib);
     }
@@ -1162,6 +1171,10 @@ pub struct PtxLinker<'a> {
 }
 
 impl<'a> Linker for PtxLinker<'a> {
+    fn cmd(&mut self) -> &mut Command {
+        &mut self.cmd
+    }
+
     fn link_rlib(&mut self, path: &Path) {
         self.cmd.arg("--rlib").arg(path);
     }
@@ -1182,10 +1195,6 @@ impl<'a> Linker for PtxLinker<'a> {
         self.cmd.arg("--bitcode").arg(path);
     }
 
-    fn args(&mut self, args: &[String]) {
-        self.cmd.args(args);
-    }
-
     fn optimize(&mut self) {
         match self.sess.lto() {
             Lto::Thin | Lto::Fat | Lto::ThinLocal => {