Minimize visibilities.

This makes it much clearer which things are used outside the crate.

compiler/rustc_codegen_ssa/src/back/command.rs

@@ -8,7 +8,7 @@ use std::{fmt, io, mem};
 use rustc_target::spec::LldFlavor;
 
 #[derive(Clone)]
-pub struct Command {
+pub(crate) struct Command {
     program: Program,
     args: Vec<OsString>,
     env: Vec<(OsString, OsString)>,
@@ -23,15 +23,15 @@ enum Program {
 }
 
 impl Command {
-    pub fn new<P: AsRef<OsStr>>(program: P) -> Command {
+    pub(crate) fn new<P: AsRef<OsStr>>(program: P) -> Command {
         Command::_new(Program::Normal(program.as_ref().to_owned()))
     }
 
-    pub fn bat_script<P: AsRef<OsStr>>(program: P) -> Command {
+    pub(crate) fn bat_script<P: AsRef<OsStr>>(program: P) -> Command {
         Command::_new(Program::CmdBatScript(program.as_ref().to_owned()))
     }
 
-    pub fn lld<P: AsRef<OsStr>>(program: P, flavor: LldFlavor) -> Command {
+    pub(crate) fn lld<P: AsRef<OsStr>>(program: P, flavor: LldFlavor) -> Command {
         Command::_new(Program::Lld(program.as_ref().to_owned(), flavor))
     }
 
@@ -39,12 +39,12 @@ impl Command {
         Command { program, args: Vec::new(), env: Vec::new(), env_remove: Vec::new() }
     }
 
-    pub fn arg<P: AsRef<OsStr>>(&mut self, arg: P) -> &mut Command {
+    pub(crate) fn arg<P: AsRef<OsStr>>(&mut self, arg: P) -> &mut Command {
         self._arg(arg.as_ref());
         self
     }
 
-    pub fn args<I>(&mut self, args: I) -> &mut Command
+    pub(crate) fn args<I>(&mut self, args: I) -> &mut Command
     where
         I: IntoIterator<Item: AsRef<OsStr>>,
     {
@@ -58,7 +58,7 @@ impl Command {
         self.args.push(arg.to_owned());
     }
 
-    pub fn env<K, V>(&mut self, key: K, value: V) -> &mut Command
+    pub(crate) fn env<K, V>(&mut self, key: K, value: V) -> &mut Command
     where
         K: AsRef<OsStr>,
         V: AsRef<OsStr>,
@@ -71,7 +71,7 @@ impl Command {
         self.env.push((key.to_owned(), value.to_owned()));
     }
 
-    pub fn env_remove<K>(&mut self, key: K) -> &mut Command
+    pub(crate) fn env_remove<K>(&mut self, key: K) -> &mut Command
     where
         K: AsRef<OsStr>,
     {
@@ -83,11 +83,11 @@ impl Command {
         self.env_remove.push(key.to_owned());
     }
 
-    pub fn output(&mut self) -> io::Result<Output> {
+    pub(crate) fn output(&mut self) -> io::Result<Output> {
         self.command().output()
     }
 
-    pub fn command(&self) -> process::Command {
+    pub(crate) fn command(&self) -> process::Command {
         let mut ret = match self.program {
             Program::Normal(ref p) => process::Command::new(p),
             Program::CmdBatScript(ref p) => {
@@ -111,17 +111,17 @@ impl Command {
 
     // extensions
 
-    pub fn get_args(&self) -> &[OsString] {
+    pub(crate) fn get_args(&self) -> &[OsString] {
         &self.args
     }
 
-    pub fn take_args(&mut self) -> Vec<OsString> {
+    pub(crate) fn take_args(&mut self) -> Vec<OsString> {
         mem::take(&mut self.args)
     }
 
     /// Returns a `true` if we're pretty sure that this'll blow OS spawn limits,
     /// or `false` if we should attempt to spawn and see what the OS says.
-    pub fn very_likely_to_exceed_some_spawn_limit(&self) -> bool {
+    pub(crate) fn very_likely_to_exceed_some_spawn_limit(&self) -> bool {
         // We mostly only care about Windows in this method, on Unix the limits
         // can be gargantuan anyway so we're pretty unlikely to hit them
         if cfg!(unix) {