.gitignore

@@ -51,6 +51,7 @@
 .hg/
 .hgignore
 .idea
+*.iml
 __pycache__/
 *.py[cod]
 *$py.class

.gitmodules

@@ -2,9 +2,6 @@
 	path = src/llvm
 	url = https://github.com/rust-lang/llvm.git
 	branch = master
-[submodule "src/compiler-rt"]
-	path = src/compiler-rt
-	url = https://github.com/rust-lang/compiler-rt.git
 [submodule "src/rt/hoedown"]
 	path = src/rt/hoedown
 	url = https://github.com/rust-lang/hoedown.git
@@ -33,3 +30,6 @@
 [submodule "src/tools/rls"]
 	path = src/tools/rls
 	url = https://github.com/rust-lang-nursery/rls.git
+[submodule "src/libcompiler_builtins"]
+	path = src/libcompiler_builtins
+	url = https://github.com/rust-lang-nursery/compiler-builtins

README.md

@@ -40,8 +40,9 @@ Read ["Installation"] from [The Book].
 
     > ***Note:*** Install locations can be adjusted by copying the config file
     > from `./src/bootstrap/config.toml.example` to `./config.toml`, and
-    > adjusting the `prefix` option under `[install]`. Various other options are
-    > also supported, and are documented in the config file.
+    > adjusting the `prefix` option under `[install]`. Various other options, such
+    > as enabling debug information, are also supported, and are documented in
+    > the config file.
 
     When complete, `sudo ./x.py install` will place several programs into
     `/usr/local/bin`: `rustc`, the Rust compiler, and `rustdoc`, the

src/bootstrap/bin/rustc.rs

@@ -75,16 +75,11 @@ fn main() {
         Err(_) => 0,
     };
 
-    // Build scripts always use the snapshot compiler which is guaranteed to be
-    // able to produce an executable, whereas intermediate compilers may not
-    // have the standard library built yet and may not be able to produce an
-    // executable. Otherwise we just use the standard compiler we're
-    // bootstrapping with.
-    //
-    // Also note that cargo will detect the version of the compiler to trigger
-    // a rebuild when the compiler changes. If this happens, we want to make
-    // sure to use the actual compiler instead of the snapshot compiler becase
-    // that's the one that's actually changing.
+    // Use a different compiler for build scripts, since there may not yet be a
+    // libstd for the real compiler to use. However, if Cargo is attempting to
+    // determine the version of the compiler, the real compiler needs to be
+    // used. Currently, these two states are differentiated based on whether
+    // --target and -vV is/isn't passed.
     let (rustc, libdir) = if target.is_none() && version.is_none() {
         ("RUSTC_SNAPSHOT", "RUSTC_SNAPSHOT_LIBDIR")
     } else {
@@ -142,6 +137,11 @@ fn main() {
             }
         }
 
+        let crate_name = args.windows(2)
+            .find(|a| &*a[0] == "--crate-name")
+            .unwrap();
+        let crate_name = &*crate_name[1];
+
         // If we're compiling specifically the `panic_abort` crate then we pass
         // the `-C panic=abort` option. Note that we do not do this for any
         // other crate intentionally as this is the only crate for now that we
@@ -150,9 +150,7 @@ fn main() {
         // This... is a bit of a hack how we detect this. Ideally this
         // information should be encoded in the crate I guess? Would likely
         // require an RFC amendment to RFC 1513, however.
-        let is_panic_abort = args.windows(2)
-            .any(|a| &*a[0] == "--crate-name" && &*a[1] == "panic_abort");
-        if is_panic_abort {
+        if crate_name == "panic_abort" {
             cmd.arg("-C").arg("panic=abort");
         }
 
@@ -167,7 +165,15 @@ fn main() {
             Ok(s) => if s == "true" { "y" } else { "n" },
             Err(..) => "n",
         };
-        cmd.arg("-C").arg(format!("debug-assertions={}", debug_assertions));
+
+        // The compiler builtins are pretty sensitive to symbols referenced in
+        // libcore and such, so we never compile them with debug assertions.
+        if crate_name == "compiler_builtins" {
+            cmd.arg("-C").arg("debug-assertions=no");
+        } else {
+            cmd.arg("-C").arg(format!("debug-assertions={}", debug_assertions));
+        }
+
         if let Ok(s) = env::var("RUSTC_CODEGEN_UNITS") {
             cmd.arg("-C").arg(format!("codegen-units={}", s));
         }

src/bootstrap/bootstrap.py

@@ -583,7 +583,7 @@ def update_submodules(self):
                                (self.get_toml('jemalloc') or
                                 self.get_mk('CFG_JEMALLOC_ROOT'))))]
         run(["git", "submodule", "update",
-             "--init"] + submodules,
+             "--init", "--recursive"] + submodules,
             cwd=self.rust_root, verbose=self.verbose)
         run(["git", "submodule", "-q", "foreach", "git",
              "reset", "-q", "--hard"],

src/bootstrap/cc.rs

@@ -42,10 +42,13 @@ use config::Target;
 pub fn find(build: &mut Build) {
     // For all targets we're going to need a C compiler for building some shims
     // and such as well as for being a linker for Rust code.
-    for target in build.config.target.iter() {
+    //
+    // This includes targets that aren't necessarily passed on the commandline
+    // (FIXME: Perhaps it shouldn't?)
+    for target in &build.config.target {
         let mut cfg = gcc::Config::new();
         cfg.cargo_metadata(false).opt_level(0).debug(false)
-           .target(target).host(&build.config.build);
+           .target(target).host(&build.build);
 
         let config = build.config.target_config.get(target);
         if let Some(cc) = config.and_then(|c| c.cc.as_ref()) {
@@ -64,10 +67,13 @@ pub fn find(build: &mut Build) {
     }
 
     // For all host triples we need to find a C++ compiler as well
-    for host in build.config.host.iter() {
+    //
+    // This includes hosts that aren't necessarily passed on the commandline
+    // (FIXME: Perhaps it shouldn't?)
+    for host in &build.config.host {
         let mut cfg = gcc::Config::new();
         cfg.cargo_metadata(false).opt_level(0).debug(false).cpp(true)
-           .target(host).host(&build.config.build);
+           .target(host).host(&build.build);
         let config = build.config.target_config.get(host);
         if let Some(cxx) = config.and_then(|c| c.cxx.as_ref()) {
             cfg.compiler(cxx);

src/bootstrap/channel.rs

@@ -23,12 +23,12 @@ use build_helper::output;
 use Build;
 
 // The version number
-pub const CFG_RELEASE_NUM: &'static str = "1.20.0";
+pub const CFG_RELEASE_NUM: &str = "1.20.0";
 
 // An optional number to put after the label, e.g. '.2' -> '-beta.2'
 // Be sure to make this starts with a dot to conform to semver pre-release
 // versions (section 9)
-pub const CFG_PRERELEASE_VERSION: &'static str = ".1";
+pub const CFG_PRERELEASE_VERSION: &str = ".1";
 
 pub struct GitInfo {
     inner: Option<Info>,
@@ -99,6 +99,10 @@ impl GitInfo {
             version.push_str(&inner.commit_date);
             version.push_str(")");
         }
-        return version
+        version
+    }
+
+    pub fn is_git(&self) -> bool {
+        self.inner.is_some()
     }
 }