Rollup merge of #130458 - nnethercote:rustc_codegen_ssa-cleanups, r=jieyouxu

`rustc_codegen_ssa` cleanups

Just some minor improvements I found while reading through this code.

r? ``@jieyouxu``

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -30,7 +30,7 @@ use crate::errors;
 /// and prevent inspection of linker output in case of errors, which we occasionally do.
 /// This should be acceptable because other messages from rustc are in English anyway,
 /// and may also be desirable to improve searchability of the linker diagnostics.
-pub fn disable_localization(linker: &mut Command) {
+pub(crate) fn disable_localization(linker: &mut Command) {
     // No harm in setting both env vars simultaneously.
     // Unix-style linkers.
     linker.env("LC_ALL", "C");
@@ -41,7 +41,7 @@ pub fn disable_localization(linker: &mut Command) {
 /// The third parameter is for env vars, used on windows to set up the
 /// path for MSVC to find its DLLs, and gcc to find its bundled
 /// toolchain
-pub fn get_linker<'a>(
+pub(crate) fn get_linker<'a>(
     sess: &'a Session,
     linker: &Path,
     flavor: LinkerFlavor,
@@ -215,28 +215,36 @@ fn link_or_cc_args<L: Linker + ?Sized>(
 macro_rules! generate_arg_methods {
     ($($ty:ty)*) => { $(
         impl $ty {
-            pub fn verbatim_args(&mut self, args: impl IntoIterator<Item: AsRef<OsStr>>) -> &mut Self {
+            #[allow(unused)]
+            pub(crate) fn verbatim_args(&mut self, args: impl IntoIterator<Item: AsRef<OsStr>>) -> &mut Self {
                 verbatim_args(self, args)
             }
-            pub fn verbatim_arg(&mut self, arg: impl AsRef<OsStr>) -> &mut Self {
+            #[allow(unused)]
+            pub(crate) fn verbatim_arg(&mut self, arg: impl AsRef<OsStr>) -> &mut Self {
                 verbatim_args(self, iter::once(arg))
             }
-            pub fn link_args(&mut self, args: impl IntoIterator<Item: AsRef<OsStr>, IntoIter: ExactSizeIterator>) -> &mut Self {
+            #[allow(unused)]
+            pub(crate) fn link_args(&mut self, args: impl IntoIterator<Item: AsRef<OsStr>, IntoIter: ExactSizeIterator>) -> &mut Self {
                 link_args(self, args)
             }
-            pub fn link_arg(&mut self, arg: impl AsRef<OsStr>) -> &mut Self {
+            #[allow(unused)]
+            pub(crate) fn link_arg(&mut self, arg: impl AsRef<OsStr>) -> &mut Self {
                 link_args(self, iter::once(arg))
             }
-            pub fn cc_args(&mut self, args: impl IntoIterator<Item: AsRef<OsStr>>) -> &mut Self {
+            #[allow(unused)]
+            pub(crate) fn cc_args(&mut self, args: impl IntoIterator<Item: AsRef<OsStr>>) -> &mut Self {
                 cc_args(self, args)
             }
-            pub fn cc_arg(&mut self, arg: impl AsRef<OsStr>) -> &mut Self {
+            #[allow(unused)]
+            pub(crate) fn cc_arg(&mut self, arg: impl AsRef<OsStr>) -> &mut Self {
                 cc_args(self, iter::once(arg))
             }
-            pub fn link_or_cc_args(&mut self, args: impl IntoIterator<Item: AsRef<OsStr>>) -> &mut Self {
+            #[allow(unused)]
+            pub(crate) fn link_or_cc_args(&mut self, args: impl IntoIterator<Item: AsRef<OsStr>>) -> &mut Self {
                 link_or_cc_args(self, args)
             }
-            pub fn link_or_cc_arg(&mut self, arg: impl AsRef<OsStr>) -> &mut Self {
+            #[allow(unused)]
+            pub(crate) fn link_or_cc_arg(&mut self, arg: impl AsRef<OsStr>) -> &mut Self {
                 link_or_cc_args(self, iter::once(arg))
             }
         }
@@ -263,7 +271,7 @@ generate_arg_methods! {
 /// represents the meaning of each option being passed down. This trait is then
 /// 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 {
+pub(crate) trait Linker {
     fn cmd(&mut self) -> &mut Command;
     fn is_cc(&self) -> bool {
         false
@@ -314,12 +322,12 @@ pub trait Linker {
 }
 
 impl dyn Linker + '_ {
-    pub fn take_cmd(&mut self) -> Command {
+    pub(crate) fn take_cmd(&mut self) -> Command {
         mem::replace(self.cmd(), Command::new(""))
     }
 }
 
-pub struct GccLinker<'a> {
+struct GccLinker<'a> {
     cmd: Command,
     sess: &'a Session,
     target_cpu: &'a str,
@@ -849,7 +857,7 @@ impl<'a> Linker for GccLinker<'a> {
     }
 }
 
-pub struct MsvcLinker<'a> {
+struct MsvcLinker<'a> {
     cmd: Command,
     sess: &'a Session,
 }
@@ -1103,7 +1111,7 @@ impl<'a> Linker for MsvcLinker<'a> {
     }
 }
 
-pub struct EmLinker<'a> {
+struct EmLinker<'a> {
     cmd: Command,
     sess: &'a Session,
 }
@@ -1220,7 +1228,7 @@ impl<'a> Linker for EmLinker<'a> {
     }
 }
 
-pub struct WasmLd<'a> {
+struct WasmLd<'a> {
     cmd: Command,
     sess: &'a Session,
 }
@@ -1404,7 +1412,7 @@ impl<'a> WasmLd<'a> {
 }
 
 /// Linker shepherd script for L4Re (Fiasco)
-pub struct L4Bender<'a> {
+struct L4Bender<'a> {
     cmd: Command,
     sess: &'a Session,
     hinted_static: bool,
@@ -1510,7 +1518,7 @@ impl<'a> Linker for L4Bender<'a> {
 }
 
 impl<'a> L4Bender<'a> {
-    pub fn new(cmd: Command, sess: &'a Session) -> L4Bender<'a> {
+    fn new(cmd: Command, sess: &'a Session) -> L4Bender<'a> {
         L4Bender { cmd, sess, hinted_static: false }
     }
 
@@ -1523,14 +1531,14 @@ impl<'a> L4Bender<'a> {
 }
 
 /// Linker for AIX.
-pub struct AixLinker<'a> {
+struct AixLinker<'a> {
     cmd: Command,
     sess: &'a Session,
     hinted_static: Option<bool>,
 }
 
 impl<'a> AixLinker<'a> {
-    pub fn new(cmd: Command, sess: &'a Session) -> AixLinker<'a> {
+    fn new(cmd: Command, sess: &'a Session) -> AixLinker<'a> {
         AixLinker { cmd, sess, hinted_static: None }
     }
 
@@ -1758,7 +1766,7 @@ pub(crate) fn linked_symbols(
 
 /// Much simplified and explicit CLI for the NVPTX linker. The linker operates
 /// with bitcode and uses LLVM backend to generate a PTX assembly.
-pub struct PtxLinker<'a> {
+struct PtxLinker<'a> {
     cmd: Command,
     sess: &'a Session,
 }
@@ -1824,7 +1832,7 @@ impl<'a> Linker for PtxLinker<'a> {
 }
 
 /// The `self-contained` LLVM bitcode linker
-pub struct LlbcLinker<'a> {
+struct LlbcLinker<'a> {
     cmd: Command,
     sess: &'a Session,
 }
@@ -1895,7 +1903,7 @@ impl<'a> Linker for LlbcLinker<'a> {
     fn linker_plugin_lto(&mut self) {}
 }
 
-pub struct BpfLinker<'a> {
+struct BpfLinker<'a> {
     cmd: Command,
     sess: &'a Session,
 }