add support for building standard crates for thumb* targets

Author: Jorge Aparicio

mk/cfg/thumbv6m-none-eabi.mk

@@ -0,0 +1 @@
+# rustbuild-only target

mk/cfg/thumbv7em-none-eabi.mk

@@ -0,0 +1 @@
+# rustbuild-only target

mk/cfg/thumbv7em-none-eabihf.mk

@@ -0,0 +1 @@
+# rustbuild-only target

mk/cfg/thumbv7m-none-eabi.mk

@@ -0,0 +1 @@
+# rustbuild-only target

src/bootstrap/check.rs

@@ -265,7 +265,7 @@ pub fn krate(build: &Build,
              target: &str,
              mode: Mode) {
     let (name, path, features) = match mode {
-        Mode::Libstd => ("libstd", "src/rustc/std_shim", build.std_features()),
+        Mode::Libstd => ("libstd", "src/rustc/std_shim", build.std_features(target)),
         Mode::Libtest => ("libtest", "src/rustc/test_shim", String::new()),
         Mode::Librustc => ("librustc", "src/rustc", build.rustc_features()),
         _ => panic!("can only test libraries"),

src/bootstrap/compile.rs

@@ -62,7 +62,7 @@ pub fn std<'a>(build: &'a Build, target: &str, compiler: &Compiler<'a>) {
     let out_dir = build.cargo_out(compiler, Mode::Libstd, target);
     build.clear_if_dirty(&out_dir, &build.compiler_path(compiler));
     let mut cargo = build.cargo(compiler, Mode::Libstd, target, "build");
-    cargo.arg("--features").arg(build.std_features())
+    cargo.arg("--features").arg(build.std_features(target))
          .arg("--manifest-path")
          .arg(build.src.join("src/rustc/std_shim/Cargo.toml"));
 

src/bootstrap/doc.rs

@@ -144,7 +144,7 @@ pub fn std(build: &Build, stage: u32, target: &str, out: &Path) {
     let mut cargo = build.cargo(&compiler, Mode::Libstd, target, "doc");
     cargo.arg("--manifest-path")
          .arg(build.src.join("src/rustc/std_shim/Cargo.toml"))
-         .arg("--features").arg(build.std_features());
+         .arg("--features").arg(build.std_features(target));
     build.run(&mut cargo);
     cp_r(&out_dir, out)
 }

src/bootstrap/lib.rs

@@ -712,17 +712,27 @@ impl Build {
 
     /// Get the space-separated set of activated features for the standard
     /// library.
-    fn std_features(&self) -> String {
+    fn std_features(&self, target: &str) -> String {
         let mut features = String::new();
-        if self.config.debug_jemalloc {
-            features.push_str(" debug-jemalloc");
-        }
-        if self.config.use_jemalloc {
-            features.push_str(" jemalloc");
-        }
-        if self.config.backtrace {
-            features.push_str(" backtrace");
+
+        if target.starts_with("thumbv6m") {
+            features.push_str(" thumb_no_atomics");
+        } else if target.starts_with("thumb") {
+            features.push_str(" thumb");
+        } else {
+            features.push_str("full");
+
+            if self.config.debug_jemalloc {
+                features.push_str(" debug-jemalloc");
+            }
+            if self.config.use_jemalloc {
+                features.push_str(" jemalloc");
+            }
+            if self.config.backtrace {
+                features.push_str(" backtrace");
+            }
         }
+
         return features
     }
 

src/rustc/std_shim/Cargo.lock

@@ -40,11 +40,23 @@ debug = false
 debug-assertions = false
 
 [dependencies]
-std = { path = "../../libstd" }
-core = { path = "../../libcore" }
+# full
+std = { path = "../../libstd", optional = true }
+
+# thumb
+compiler_builtins = { path = "../../libcompiler_builtins", optional = true }
+core = { path = "../../libcore", optional = true }
+rustc_unicode = { path = "../../librustc_unicode", optional = true }
+
+# thumb-no-atomics
+collections = { path = "../../libcollections", optional = true }
+rand = { path = "../../librand", optional = true }
 
 # Reexport features from std
 [features]
-jemalloc = ["std/jemalloc"]
-debug-jemalloc = ["std/debug-jemalloc"]
 backtrace = ["std/backtrace"]
+debug-jemalloc = ["std/debug-jemalloc"]
+jemalloc = ["std/jemalloc"]
+full = ["core", "std"]
+thumb_no_atomics  = ["compiler_builtins", "core", "rustc_unicode"]
+thumb = ["core", "compiler_builtins", "collections", "rand"]

src/rustc/std_shim/Cargo.toml

@@ -14,4 +14,3 @@
 // compiling then this doesn't work with `#[macro_use] extern crate std;`. Work
 // around this by not having `#[macro_use] extern crate std;`
 #![no_std]
-extern crate std;