rustc: add a --print targets command

src/librustc/session/config.rs

@@ -164,6 +164,7 @@ pub enum PrintRequest {
     Sysroot,
     CrateName,
     Cfg,
+    TargetList,
 }
 
 pub enum Input {
@@ -844,7 +845,7 @@ pub fn rustc_short_optgroups() -> Vec<RustcOptGroup> {
                  "[asm|llvm-bc|llvm-ir|obj|link|dep-info]"),
         opt::multi("", "print", "Comma separated list of compiler information to \
                                print on stdout",
-                 "[crate-name|file-names|sysroot]"),
+                 "[crate-name|file-names|sysroot|target-list]"),
         opt::flagmulti("g",  "",  "Equivalent to -C debuginfo=2"),
         opt::flagmulti("O", "", "Equivalent to -C opt-level=2"),
         opt::opt("o", "", "Write output to <filename>", "FILENAME"),
@@ -1109,6 +1110,7 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
             "file-names" => PrintRequest::FileNames,
             "sysroot" => PrintRequest::Sysroot,
             "cfg" => PrintRequest::Cfg,
+            "target-list" => PrintRequest::TargetList,
             req => {
                 early_error(error_format, &format!("unknown print request `{}`", req))
             }

src/librustc_back/target/mod.rs

@@ -63,6 +63,82 @@ mod solaris_base;
 mod windows_base;
 mod windows_msvc_base;
 
+macro_rules! supported_targets {
+    ( $(($triple:expr, $module:ident)),+ ) => (
+        /// List of supported targets
+        pub const TARGETS: &'static [&'static str] = &[$($triple),*];
+
+        // this would use a match if stringify! were allowed in pattern position
+        fn load_specific(target: &str) -> Option<Target> {
+            $(mod $module;)*
+            let target = target.replace("-", "_");
+            if false { }
+            $(
+                else if target == stringify!($module) {
+                    let t = $module::target();
+                    debug!("Got builtin target: {:?}", t);
+                    return Some(t);
+                }
+            )*
+
+            None
+        }
+    )
+}
+
+supported_targets! {
+    ("x86_64-unknown-linux-gnu", x86_64_unknown_linux_gnu),
+    ("i686-unknown-linux-gnu", i686_unknown_linux_gnu),
+    ("mips-unknown-linux-gnu", mips_unknown_linux_gnu),
+    ("mipsel-unknown-linux-gnu", mipsel_unknown_linux_gnu),
+    ("powerpc-unknown-linux-gnu", powerpc_unknown_linux_gnu),
+    ("powerpc64-unknown-linux-gnu", powerpc64_unknown_linux_gnu),
+    ("powerpc64le-unknown-linux-gnu", powerpc64le_unknown_linux_gnu),
+    ("arm-unknown-linux-gnueabi", arm_unknown_linux_gnueabi),
+    ("arm-unknown-linux-gnueabihf", arm_unknown_linux_gnueabihf),
+    ("armv7-unknown-linux-gnueabihf", armv7_unknown_linux_gnueabihf),
+    ("aarch64-unknown-linux-gnu", aarch64_unknown_linux_gnu),
+    ("x86_64-unknown-linux-musl", x86_64_unknown_linux_musl),
+    ("i686-unknown-linux-musl", i686_unknown_linux_musl),
+    ("mips-unknown-linux-musl", mips_unknown_linux_musl),
+    ("mipsel-unknown-linux-musl", mipsel_unknown_linux_musl),
+
+    ("i686-linux-android", i686_linux_android),
+    ("arm-linux-androideabi", arm_linux_androideabi),
+    ("aarch64-linux-android", aarch64_linux_android),
+
+    ("i686-unknown-freebsd", i686_unknown_freebsd),
+    ("x86_64-unknown-freebsd", x86_64_unknown_freebsd),
+
+    ("i686-unknown-dragonfly", i686_unknown_dragonfly),
+    ("x86_64-unknown-dragonfly", x86_64_unknown_dragonfly),
+
+    ("x86_64-unknown-bitrig", x86_64_unknown_bitrig),
+    ("x86_64-unknown-openbsd", x86_64_unknown_openbsd),
+    ("x86_64-unknown-netbsd", x86_64_unknown_netbsd),
+    ("x86_64-rumprun-netbsd", x86_64_rumprun_netbsd),
+
+    ("x86_64-apple-darwin", x86_64_apple_darwin),
+    ("i686-apple-darwin", i686_apple_darwin),
+
+    ("i386-apple-ios", i386_apple_ios),
+    ("x86_64-apple-ios", x86_64_apple_ios),
+    ("aarch64-apple-ios", aarch64_apple_ios),
+    ("armv7-apple-ios", armv7_apple_ios),
+    ("armv7s-apple-ios", armv7s_apple_ios),
+
+    ("x86_64-sun-solaris", x86_64_sun_solaris),
+
+    ("x86_64-pc-windows-gnu", x86_64_pc_windows_gnu),
+    ("i686-pc-windows-gnu", i686_pc_windows_gnu),
+
+    ("x86_64-pc-windows-msvc", x86_64_pc_windows_msvc),
+    ("i686-pc-windows-msvc", i686_pc_windows_msvc),
+
+    ("le32-unknown-nacl", le32_unknown_nacl),
+    ("asmjs-unknown-emscripten", asmjs_unknown_emscripten)
+}
+
 /// Everything `rustc` knows about how to compile for a specific target.
 ///
 /// Every field here must be specified, and has no default value.
@@ -393,85 +469,10 @@ impl Target {
             Ok(Target::from_json(obj))
         }
 
-        // this would use a match if stringify! were allowed in pattern position
-        macro_rules! load_specific {
-            ( $($name:ident),+ ) => (
-                {
-                    $(mod $name;)*
-                    let target = target.replace("-", "_");
-                    if false { }
-                    $(
-                        else if target == stringify!($name) {
-                            let t = $name::target();
-                            debug!("Got builtin target: {:?}", t);
-                            return Ok(t);
-                        }
-                    )*
-                    else if target == "x86_64-w64-mingw32" {
-                        let t = x86_64_pc_windows_gnu::target();
-                        return Ok(t);
-                    } else if target == "i686-w64-mingw32" {
-                        let t = i686_pc_windows_gnu::target();
-                        return Ok(t);
-                    }
-                }
-            )
+        if let Some(t) = load_specific(target) {
+            return Ok(t)
         }
 
-        load_specific!(
-            x86_64_unknown_linux_gnu,
-            i686_unknown_linux_gnu,
-            mips_unknown_linux_gnu,
-            mipsel_unknown_linux_gnu,
-            powerpc_unknown_linux_gnu,
-            powerpc64_unknown_linux_gnu,
-            powerpc64le_unknown_linux_gnu,
-            arm_unknown_linux_gnueabi,
-            arm_unknown_linux_gnueabihf,
-            armv7_unknown_linux_gnueabihf,
-            aarch64_unknown_linux_gnu,
-            x86_64_unknown_linux_musl,
-            i686_unknown_linux_musl,
-            mips_unknown_linux_musl,
-            mipsel_unknown_linux_musl,
-
-            i686_linux_android,
-            arm_linux_androideabi,
-            aarch64_linux_android,
-
-            i686_unknown_freebsd,
-            x86_64_unknown_freebsd,
-
-            i686_unknown_dragonfly,
-            x86_64_unknown_dragonfly,
-
-            x86_64_unknown_bitrig,
-            x86_64_unknown_openbsd,
-            x86_64_unknown_netbsd,
-            x86_64_rumprun_netbsd,
-
-            x86_64_apple_darwin,
-            i686_apple_darwin,
-
-            i386_apple_ios,
-            x86_64_apple_ios,
-            aarch64_apple_ios,
-            armv7_apple_ios,
-            armv7s_apple_ios,
-
-            x86_64_sun_solaris,
-
-            x86_64_pc_windows_gnu,
-            i686_pc_windows_gnu,
-
-            x86_64_pc_windows_msvc,
-            i686_pc_windows_msvc,
-
-            le32_unknown_nacl,
-            asmjs_unknown_emscripten
-        );
-
-
         let path = Path::new(target);
 
         if path.is_file() {

src/librustc_driver/lib.rs

@@ -532,6 +532,11 @@ impl RustcDefaultCalls {
         let attrs = input.map(|input| parse_crate_attrs(sess, input));
         for req in &sess.opts.prints {
             match *req {
+                PrintRequest::TargetList => {
+                    let mut targets = rustc_back::target::TARGETS.to_vec();
+                    targets.sort();
+                    println!("{}", targets.join("\n"));
+                },
                 PrintRequest::Sysroot => println!("{}", sess.sysroot().display()),
                 PrintRequest::FileNames |
                 PrintRequest::CrateName => {

src/test/run-make/print-target-list/Makefile

@@ -0,0 +1,15 @@
+-include ../tools.mk
+
+# Checks that all the targets returned by `rustc --print target-list` are valid
+# target specifications
+# TODO remove the '*ios*' case when rust-lang/rust#29812 is fixed
+all:
+	for target in $(shell $(BARE_RUSTC) --print target-list); do \
+		case $$target in \
+			*ios*) \
+				;; \
+			*) \
+				$(BARE_RUSTC) --target $$target --print sysroot \
+				;; \
+			esac \
+	done