cleanup: rustc doesn't use an external archiver

config.toml.example

@@ -250,14 +250,11 @@
 # Whether or not `panic!`s generate backtraces (RUST_BACKTRACE)
 #backtrace = true
 
-# The default linker that will be used by the generated compiler. Note that this
-# is not the linker used to link said compiler.
+# The default linker that will be hard-coded into the generated compiler for
+# targets that don't specify linker explicitly in their target specifications.
+# Note that this is not the linker used to link said compiler.
 #default-linker = "cc"
 
-# The default ar utility that will be used by the generated compiler if LLVM
-# cannot be used. Note that this is not used to assemble said compiler.
-#default-ar = "ar"
-
 # The "channel" for the Rust build to produce. The stable/beta channels only
 # allow using stable features, whereas the nightly and dev channels allow using
 # nightly features

src/bootstrap/compile.rs

@@ -560,9 +560,6 @@ pub fn rustc_cargo(build: &Build,
     if let Some(ref s) = build.config.rustc_default_linker {
         cargo.env("CFG_DEFAULT_LINKER", s);
     }
-    if let Some(ref s) = build.config.rustc_default_ar {
-        cargo.env("CFG_DEFAULT_AR", s);
-    }
 }
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]

src/bootstrap/config.rs

@@ -88,7 +88,6 @@ pub struct Config {
     pub rust_debuginfo_only_std: bool,
     pub rust_rpath: bool,
     pub rustc_default_linker: Option<String>,
-    pub rustc_default_ar: Option<String>,
     pub rust_optimize_tests: bool,
     pub rust_debuginfo_tests: bool,
     pub rust_dist_src: bool,
@@ -262,7 +261,6 @@ struct Rust {
     use_jemalloc: Option<bool>,
     backtrace: Option<bool>,
     default_linker: Option<String>,
-    default_ar: Option<String>,
     channel: Option<String>,
     musl_root: Option<String>,
     rpath: Option<bool>,
@@ -464,7 +462,6 @@ impl Config {
             set(&mut config.quiet_tests, rust.quiet_tests);
             set(&mut config.test_miri, rust.test_miri);
             config.rustc_default_linker = rust.default_linker.clone();
-            config.rustc_default_ar = rust.default_ar.clone();
             config.musl_root = rust.musl_root.clone().map(PathBuf::from);
 
             match rust.codegen_units {

src/bootstrap/configure.py

@@ -119,9 +119,8 @@ def v(*args):
   "experimental LLVM targets to build")
 v("release-channel", "rust.channel", "the name of the release channel to build")
 
-# Used on systems where "cc" and "ar" are unavailable
+# Used on systems where "cc" is unavailable
 v("default-linker", "rust.default-linker", "the default linker")
-v("default-ar", "rust.default-ar", "the default ar")
 
 # Many of these are saved below during the "writing configuration" step
 # (others are conditionally saved).

src/bootstrap/dist.rs

@@ -176,7 +176,7 @@ fn make_win_dist(
         }
     }
 
-    let target_tools = ["gcc.exe", "ld.exe", "ar.exe", "dlltool.exe", "libwinpthread-1.dll"];
+    let target_tools = ["gcc.exe", "ld.exe", "dlltool.exe", "libwinpthread-1.dll"];
     let mut rustc_dlls = vec!["libstdc++-6.dll", "libwinpthread-1.dll"];
     if target_triple.starts_with("i686-") {
         rustc_dlls.push("libgcc_s_dw2-1.dll");

src/doc/man/rustc.1

@@ -152,9 +152,6 @@ never colorize output.
 
 .SH CODEGEN OPTIONS
 
-.TP
-\fBar\fR=\fI/path/to/ar\fR
-Path to the archive utility to use when assembling archives.
 .TP
 \fBlinker\fR=\fI/path/to/cc\fR
 Path to the linker utility to use when linking libraries, executables, and

src/librustc/session/config.rs

@@ -864,8 +864,7 @@ options! {CodegenOptions, CodegenSetter, basic_codegen_options,
          build_codegen_options, "C", "codegen",
          CG_OPTIONS, cg_type_desc, cgsetters,
     ar: Option<String> = (None, parse_opt_string, [UNTRACKED],
-        "tool to assemble archives with (has no effect currently, \
-         rustc doesn't use an external archiver)"),
+        "this option is deprecated and does nothing"),
     linker: Option<String> = (None, parse_opt_string, [UNTRACKED],
         "system linker to link outputs with"),
     link_arg: Vec<String> = (vec![], parse_string_push, [UNTRACKED],

src/librustc_back/build.rs

@@ -11,5 +11,4 @@
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
     println!("cargo:rerun-if-env-changed=CFG_DEFAULT_LINKER");
-    println!("cargo:rerun-if-env-changed=CFG_DEFAULT_AR");
 }

src/librustc_back/target/asmjs_unknown_emscripten.rs

@@ -20,7 +20,6 @@ pub fn target() -> Result<Target, String> {
 
     let opts = TargetOptions {
         linker: cmd("emcc"),
-        ar: cmd("emar"),
 
         dynamic_linking: false,
         executables: true,

src/librustc_back/target/mod.rs

@@ -268,8 +268,6 @@ pub struct TargetOptions {
 
     /// Linker to invoke. Defaults to "cc".
     pub linker: String,
-    /// Archive utility to use when managing archives. Defaults to "ar".
-    pub ar: String,
 
     /// Linker arguments that are unconditionally passed *before* any
     /// user-defined libraries.
@@ -439,7 +437,6 @@ impl Default for TargetOptions {
         TargetOptions {
             is_builtin: false,
             linker: option_env!("CFG_DEFAULT_LINKER").unwrap_or("cc").to_string(),
-            ar: option_env!("CFG_DEFAULT_AR").unwrap_or("ar").to_string(),
             pre_link_args: LinkArgs::new(),
             post_link_args: LinkArgs::new(),
             asm_args: Vec::new(),
@@ -680,7 +677,6 @@ impl Target {
 
         key!(is_builtin, bool);
         key!(linker);
-        key!(ar);
         key!(pre_link_args, link_args);
         key!(pre_link_objects_exe, list);
         key!(pre_link_objects_dll, list);
@@ -872,7 +868,6 @@ impl ToJson for Target {
 
         target_option_val!(is_builtin);
         target_option_val!(linker);
-        target_option_val!(ar);
         target_option_val!(link_args - pre_link_args);
         target_option_val!(pre_link_objects_exe);
         target_option_val!(pre_link_objects_dll);

src/librustc_back/target/wasm32_experimental_emscripten.rs

@@ -25,7 +25,6 @@ pub fn target() -> Result<Target, String> {
 
     let opts = TargetOptions {
         linker: cmd("emcc"),
-        ar: cmd("emar"),
 
         dynamic_linking: false,
         executables: true,

src/librustc_back/target/wasm32_unknown_emscripten.rs

@@ -22,7 +22,6 @@ pub fn target() -> Result<Target, String> {
 
     let opts = TargetOptions {
         linker: cmd("emcc"),
-        ar: cmd("emar"),
 
         dynamic_linking: false,
         executables: true,

src/librustc_back/target/windows_msvc_base.rs

@@ -21,37 +21,6 @@ pub fn opts() -> TargetOptions {
     TargetOptions {
         function_sections: true,
         linker: "link.exe".to_string(),
-        // When taking a look at the value of this `ar` field, one might expect
-        // `lib.exe` to be the value here! The `lib.exe` program is the default
-        // tool for managing `.lib` archives on Windows, but unfortunately the
-        // compiler cannot use it.
-        //
-        // To recap, we use `ar` here to manage rlibs (which are just archives).
-        // LLVM does not expose bindings for modifying archives so we have to
-        // invoke this utility for write operations (e.g. deleting files, adding
-        // files, etc). Normally archives only have object files within them,
-        // but the compiler also uses archives for storing metadata and
-        // compressed bytecode, so we don't exactly fall within "normal use
-        // cases".
-        //
-        // MSVC's `lib.exe` tool by default will choke when adding a non-object
-        // file to an archive, which we do on a regular basis, making it
-        // inoperable for us. Luckily, however, LLVM has already rewritten `ar`
-        // in the form of `llvm-ar` which is built by default when we build
-        // LLVM. This tool, unlike `lib.exe`, works just fine with non-object
-        // files, so we use it instead.
-        //
-        // Note that there's a few caveats associated with this:
-        //
-        // * This still requires that the *linker* (the consumer of rlibs) will
-        //   ignore non-object files. Thankfully `link.exe` on Windows does
-        //   indeed ignore non-object files in archives.
-        // * This requires `llvm-ar.exe` to be distributed with the compiler
-        //   itself, but we already make sure of this elsewhere.
-        //
-        // Perhaps one day we won't even need this tool at all and we'll just be
-        // able to make library calls into LLVM!
-        ar: "llvm-ar.exe".to_string(),
         dynamic_linking: true,
         executables: true,
         dll_prefix: "".to_string(),

src/librustc_back/target/x86_64_rumprun_netbsd.rs

@@ -16,7 +16,6 @@ pub fn target() -> TargetResult {
     base.cpu = "x86-64".to_string();
     base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
     base.linker = "x86_64-rumprun-netbsd-gcc".to_string();
-    base.ar = "x86_64-rumprun-netbsd-ar".to_string();
     base.max_atomic_width = Some(64);
 
     base.dynamic_linking = false;

src/librustc_trans/back/archive.rs

@@ -31,8 +31,7 @@ pub struct ArchiveConfig<'a> {
     pub lib_search_paths: Vec<PathBuf>,
 }
 
-/// Helper for adding many files to an archive with a single invocation of
-/// `ar`.
+/// Helper for adding many files to an archive.
 #[must_use = "must call build() to finish building the archive"]
 pub struct ArchiveBuilder<'a> {
     config: ArchiveConfig<'a>,
@@ -201,8 +200,8 @@ impl<'a> ArchiveBuilder<'a> {
         });
     }
 
-    /// Indicate that the next call to `build` should updates all symbols in
-    /// the archive (run 'ar s' over it).
+    /// Indicate that the next call to `build` should update all symbols in
+    /// the archive (equivalent to running 'ar s' over it).
     pub fn update_symbols(&mut self) {
         self.should_update_symbols = true;
     }