Update Rust to 1.22.0-nightly (a47c9f870 2017-10-11)

This allows us to start experimenting with -Z thinlto

python/servo/command_base.py

@@ -273,6 +273,7 @@ class CommandBase(object):
         self.config["build"].setdefault("ccache", "")
         self.config["build"].setdefault("rustflags", "")
         self.config["build"].setdefault("incremental", False)
+        self.config["build"].setdefault("thinlto", False)
 
         self.config.setdefault("android", {})
         self.config["android"].setdefault("sdk", "")
@@ -532,6 +533,8 @@ class CommandBase(object):
         if geckolib:
             geckolib_build_path = path.join(self.context.topdir, "target", "geckolib").encode("UTF-8")
             env["CARGO_TARGET_DIR"] = geckolib_build_path
+        elif self.config["build"]["thinlto"]:
+            env['RUSTFLAGS'] += " -Z thinlto"
 
         return env
 

rust-toolchain

@@ -1 +1 @@
-nightly-2017-10-05
+nightly-2017-10-12

servobuild.example

@@ -57,6 +57,9 @@ debug-mozjs = false
 # Enable rustc’s incremental compilation
 #incremental = false
 
+# Whether to use ThinLTO or not
+#thinlto = false
+
 # Android information
 [android]
 # Defaults to the value of $ANDROID_SDK, $ANDROID_NDK, $ANDROID_TOOLCHAIN, $ANDROID_PLATFORM respectively