Fix issue where rustbuild expected msvc to have ar

src/bootstrap/build/cc.rs

@@ -57,7 +57,9 @@ pub fn find(build: &mut Build) {
         let compiler = cfg.get_compiler();
         let ar = cc2ar(compiler.path(), target);
         build.verbose(&format!("CC_{} = {:?}", target, compiler.path()));
-        build.verbose(&format!("AR_{} = {:?}", target, ar));
+        if let Some(ref ar) = ar {
+            build.verbose(&format!("AR_{} = {:?}", target, ar));
+        }
         build.cc.insert(target.to_string(), (compiler, ar));
     }
 

src/bootstrap/build/mod.rs

@@ -119,7 +119,7 @@ pub struct Build {
     lldb_python_dir: Option<String>,
 
     // Runtime state filled in later on
-    cc: HashMap<String, (gcc::Tool, PathBuf)>,
+    cc: HashMap<String, (gcc::Tool, Option<PathBuf>)>,
     cxx: HashMap<String, gcc::Tool>,
     compiler_rt_built: RefCell<HashMap<String, PathBuf>>,
 }
@@ -549,7 +549,7 @@ impl Build {
         // FIXME: the guard against msvc shouldn't need to be here
         if !target.contains("msvc") {
             cargo.env(format!("CC_{}", target), self.cc(target))
-                 .env(format!("AR_{}", target), self.ar(target))
+                 .env(format!("AR_{}", target), self.ar(target).unwrap()) // only msvc is None
                  .env(format!("CFLAGS_{}", target), self.cflags(target).join(" "));
         }
 
@@ -825,8 +825,8 @@ impl Build {
     }
 
     /// Returns the path to the `ar` archive utility for the target specified.
-    fn ar(&self, target: &str) -> &Path {
-        &self.cc[target].1
+    fn ar(&self, target: &str) -> Option<&Path> {
+        self.cc[target].1.as_ref().map(|p| &**p)
     }
 
     /// Returns the path to the C++ compiler for the target specified, may panic

src/bootstrap/build/sanity.rs

@@ -70,7 +70,9 @@ pub fn check(build: &mut Build) {
     // also build some C++ shims for LLVM so we need a C++ compiler.
     for target in build.config.target.iter() {
         need_cmd(build.cc(target).as_ref());
-        need_cmd(build.ar(target).as_ref());
+        if let Some(ar) = build.ar(target) {
+            need_cmd(ar.as_ref());
+        }
     }
     for host in build.config.host.iter() {
         need_cmd(build.cxx(host).as_ref());

src/build_helper/lib.rs

@@ -39,20 +39,22 @@ pub fn gnu_target(target: &str) -> String {
     }
 }
 
-pub fn cc2ar(cc: &Path, target: &str) -> PathBuf {
-    if target.contains("musl") || target.contains("msvc") {
-        PathBuf::from("ar")
+pub fn cc2ar(cc: &Path, target: &str) -> Option<PathBuf> {
+    if target.contains("msvc") {
+        None
+    } else if target.contains("musl") {
+        Some(PathBuf::from("ar"))
     } else {
         let parent = cc.parent().unwrap();
         let file = cc.file_name().unwrap().to_str().unwrap();
         for suffix in &["gcc", "cc", "clang"] {
             if let Some(idx) = file.rfind(suffix) {
                 let mut file = file[..idx].to_owned();
                 file.push_str("ar");
-                return parent.join(&file);
+                return Some(parent.join(&file));
             }
         }
-        parent.join(file)
+        Some(parent.join(file))
     }
 }
 

src/liballoc_jemalloc/build.rs

@@ -43,7 +43,8 @@ fn main() {
     }
 
     let compiler = gcc::Config::new().get_compiler();
-    let ar = build_helper::cc2ar(compiler.path(), &target);
+    // only msvc returns None for ar so unwrap is okay
+    let ar = build_helper::cc2ar(compiler.path(), &target).unwrap();
     let cflags = compiler.args()
                          .iter()
                          .map(|s| s.to_str().unwrap())

src/libstd/build.rs

@@ -80,7 +80,8 @@ fn build_libbacktrace(host: &str, target: &str) {
     }
 
     let compiler = gcc::Config::new().get_compiler();
-    let ar = build_helper::cc2ar(compiler.path(), target);
+    // only msvc returns None for ar so unwrap is okay
+    let ar = build_helper::cc2ar(compiler.path(), target).unwrap();
     let cflags = compiler.args().iter().map(|s| s.to_str().unwrap())
                          .collect::<Vec<_>>().join(" ");
     run(Command::new("sh")