Auto merge of #40123 - TimNN:llvm40, r=<try>

[WIP] LLVM 4.0 Upgrade

Since nobody has done this yet, I decided to get things started:

**Todo:**

* [ ] push the relevant commits to `rust-lang/llvm` and `rust-lang/compiler-rt`
* [ ] cleanup `.gitmodules`
* [ ] Verify if there are any other commits from `rust-lang/llvm` which need backporting
* [x] Investigate / fix debuginfo ("`<optimized out>`") failures
* [x] Use correct emscripten version in docker image

---

Closes #37609.

---

**Test results:**

* `FAIL`: `IMAGE=armhf-gnu` [travis](https://travis-ci.org/rust-lang/rust/jobs/205860539) (looks to be qemu related, or rather the client / server tools)
* `FAIL`: `IMAGE=emscripten` [travis](https://travis-ci.org/rust-lang/rust/jobs/205978867) (with an updated emcc: one bad emcc optimization: emscripten-core/emscripten-fastcomp#176) ~~[travis](https://travis-ci.org/rust-lang/rust/jobs/205860559) (mainly (only?) due to emcc / rust llvm version mismatch)~~
* `FAIL`: `IMAGE=dist-powerpc64-linux` [travis](https://travis-ci.org/rust-lang/rust/jobs/206514546) (llvm unreachable when compiling core: `Invalid PPC CTR loop!
UNREACHABLE executed at .../PPCCTRLoops.cpp:722!`, reported as [upstream bug #32485](https://bugs.llvm.org//show_bug.cgi?id=32485))
* `SUCCESS/TIMEOUT`: `IMAGE=dist-arm-linux` [travis](https://travis-ci.org/rust-lang/rust/jobs/206514540) (passes locally)
* `SUCCESS/TIMEOUT`: `IMAGE=dist-armv7-aarch64-linux` [travis](https://travis-ci.org/rust-lang/rust/jobs/206514541) (passes locally)
* `SUCCESS`: `IMAGE=arm-android` (fixed)
* `SUCCESS`: `IMAGE=cross`
* `SUCCESS`: `IMAGE=linux-tested-targets`
* `SUCCESS`: `IMAGE=dist-android`
* `SUCCESS`: `IMAGE=dist-freebsd` (fixed)
* `SUCCESS`: `IMAGE=dist-fuchsia`
* `SUCCESS`: `IMAGE=dist-mips-linux`
* `SUCCESS`: `IMAGE=dist-mips64-linux`
* `SUCCESS`: `IMAGE=dist-powerpc-linux`
* `SUCCESS`: `IMAGE=dist-s390x-linux-netbsd` (fixed)
* `SUCCESS`: `IMAGE=dist-x86-linux` (fixed)
* `SUCCESS`: `IMAGE=i686-gnu`
* `SUCCESS`: `IMAGE=i686-gnu-nopt`
* `SUCCESS`: `IMAGE=x86_64-gnu-llvm-3.7`
* `SUCCESS`: `IMAGE=x86_64-gnu`
* `SUCCESS`: `IMAGE=x86_64-gnu-aux`
* `SUCCESS`: `IMAGE=x86_64-gnu-debug`
* `SUCCESS`: `IMAGE=x86_64-gnu-nopt`
* `SUCCESS`: `IMAGE=x86_64-gnu-full-bootstrap`
* `SUCCESS`: `IMAGE=x86_64-gnu-distcheck`
* `SUCCESS`: `IMAGE=x86_64-gnu-incremental`

.gitmodules

@@ -1,10 +1,10 @@
 [submodule "src/llvm"]
 	path = src/llvm
-	url = https://github.com/rust-lang/llvm.git
+	url = https://github.com/TimNN/llvm.git
 	branch = master
 [submodule "src/compiler-rt"]
 	path = src/compiler-rt
-	url = https://github.com/rust-lang/compiler-rt.git
+	url = https://github.com/llvm-mirror/compiler-rt.git
 [submodule "src/jemalloc"]
 	path = src/jemalloc
 	url = https://github.com/rust-lang/jemalloc.git

src/ci/docker/emscripten/Dockerfile

@@ -27,10 +27,10 @@ WORKDIR /tmp
 COPY build-emscripten.sh /tmp/
 RUN ./build-emscripten.sh
 ENV PATH=$PATH:/tmp/emsdk_portable
-ENV PATH=$PATH:/tmp/emsdk_portable/clang/tag-e1.37.1/build_tag-e1.37.1_32/bin
+ENV PATH=$PATH:/tmp/emsdk_portable/clang/fastcomp/build_incoming_32/bin
 ENV PATH=$PATH:/tmp/emsdk_portable/node/4.1.1_32bit/bin
-ENV PATH=$PATH:/tmp/emsdk_portable/emscripten/tag-1.37.1
-ENV EMSCRIPTEN=/tmp/emsdk_portable/emscripten/tag-1.37.1
+ENV PATH=$PATH:/tmp/emsdk_portable/emscripten/incoming
+ENV EMSCRIPTEN=/tmp/emsdk_portable/emscripten/incoming
 
 ENV RUST_CONFIGURE_ARGS --target=asmjs-unknown-emscripten
 

src/ci/docker/emscripten/build-emscripten.sh

@@ -49,5 +49,5 @@ chmod 755 emsdk_portable
 
 source emsdk_portable/emsdk_env.sh
 hide_output emsdk update
-hide_output emsdk install --build=Release sdk-tag-1.37.1-32bit
-hide_output emsdk activate --build=Release sdk-tag-1.37.1-32bit
+hide_output emsdk install --build=Release --enable-assertions sdk-incoming-32bit
+hide_output emsdk activate --build=Release sdk-incoming-32bit

src/ci/docker/run.sh

@@ -18,16 +18,17 @@ docker_dir="`dirname $script`"
 ci_dir="`dirname $docker_dir`"
 src_dir="`dirname $ci_dir`"
 root_dir="`dirname $src_dir`"
+tag=rust-ci-$image
 
 source "$ci_dir/shared.sh"
 
-retry docker \
+docker \
   build \
   --rm \
-  -t rust-ci \
+  -t $tag \
   "`dirname "$script"`/$image"
 
-objdir=$root_dir/obj
+objdir=$root_dir/obj/$image
 
 mkdir -p $HOME/.cargo
 mkdir -p $objdir/tmp
@@ -60,5 +61,5 @@ exec docker \
   --volume "$HOME/rustsrc:$HOME/rustsrc" \
   --privileged \
   --rm \
-  rust-ci \
+  $tag \
   /checkout/src/ci/run.sh

src/ci/run.sh

@@ -9,7 +9,13 @@
 # option. This file may not be copied, modified, or distributed
 # except according to those terms.
 
-set -e
+set -eE
+
+function err(){
+  sleep infinity
+}
+
+trap "err" ERR
 
 if [ "$NO_CHANGE_USER" = "" ]; then
   if [ "$LOCAL_USER_ID" != "" ]; then

src/libcompiler_builtins/build.rs

@@ -293,6 +293,12 @@ fn main() {
     }
 
     if target.contains("arm") && !target.contains("ios") {
+        // (At least) udivsi3.S is broken for Thumb 1 which our gcc uses by
+        // default, we don't want Thumb 2 since it isn't supported on some
+        // devices, so disable thumb entirely.
+        // Upstream bug: https://bugs.llvm.org/show_bug.cgi?id=32492
+        cfg.define("__ARM_ARCH_ISA_THUMB", Some("0"));
+
         sources.extend(&["arm/aeabi_cdcmp.S",
                          "arm/aeabi_cdcmpeq_check_nan.c",
                          "arm/aeabi_cfcmp.S",

src/test/run-pass/panic-runtime/abort-link-to-unwinding-crates.rs

@@ -27,7 +27,17 @@ fn main() {
             exit_success_if_unwind::bar(do_panic);
         }
     }
-    let s = Command::new(env::args_os().next().unwrap()).arg("foo").status();
+
+    let mut cmd = Command::new(env::args_os().next().unwrap());
+    cmd.arg("foo");
+
+
+    // ARMv6 hanges while printing the backtrace, see #41004
+    if cfg!(target_arch = "arm") && cfg!(target_env = "gnu") {
+        cmd.env("RUST_BACKTRACE", "0");
+    }
+
+    let s = cmd.status();
     assert!(s.unwrap().code() != Some(0));
 }
 

src/test/run-pass/panic-runtime/abort.rs

@@ -35,6 +35,15 @@ fn main() {
             panic!("try to catch me");
         }
     }
-    let s = Command::new(env::args_os().next().unwrap()).arg("foo").status();
+
+    let mut cmd = Command::new(env::args_os().next().unwrap());
+    cmd.arg("foo");
+
+    // ARMv6 hanges while printing the backtrace, see #41004
+    if cfg!(target_arch = "arm") && cfg!(target_env = "gnu") {
+        cmd.env("RUST_BACKTRACE", "0");
+    }
+
+    let s = cmd.status();
     assert!(s.unwrap().code() != Some(0));
 }

src/tools/qemu-test-client/src/main.rs

@@ -51,6 +51,9 @@ fn main() {
 }
 
 fn spawn_emulator(rootfs: &Path, tmpdir: &Path) {
+    use std::os::unix::io::{FromRawFd, IntoRawFd};
+    use std::fs::OpenOptions;
+
     // Generate a new rootfs image now that we've updated the test server
     // executable. This is the equivalent of:
     //
@@ -71,6 +74,10 @@ fn spawn_emulator(rootfs: &Path, tmpdir: &Path) {
                 &mut t!(File::create(&rootfs_img))));
     assert!(t!(child.wait()).success());
 
+    let log = OpenOptions::new().create(true).append(true).open("qemu.log").unwrap();
+    let qout = unsafe { Stdio::from_raw_fd(log.try_clone().unwrap().into_raw_fd()) };
+    let qerr = unsafe { Stdio::from_raw_fd(log.try_clone().unwrap().into_raw_fd()) };
+
     // Start up the emulator, in the background
     let mut cmd = Command::new("qemu-system-arm");
     cmd.arg("-M").arg("vexpress-a15")
@@ -80,7 +87,8 @@ fn spawn_emulator(rootfs: &Path, tmpdir: &Path) {
        .arg("-dtb").arg("/tmp/vexpress-v2p-ca15-tc1.dtb")
        .arg("-append").arg("console=ttyAMA0 root=/dev/ram rdinit=/sbin/init init=/sbin/init")
        .arg("-nographic")
-       .arg("-redir").arg("tcp:12345::12345");
+       .arg("-redir").arg("tcp:12345::12345")
+       .stdout(qout).stderr(qerr);
     t!(cmd.spawn());
 
     // Wait for the emulator to come online

src/tools/qemu-test-server/src/main.rs

@@ -8,6 +8,10 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![feature(libc)]
+
+extern crate libc;
+
 /// This is a small server which is intended to run inside of an emulator. This
 /// server pairs with the `qemu-test-client` program in this repository. The
 /// `qemu-test-client` connects to this server over a TCP socket and performs
@@ -41,7 +45,31 @@ macro_rules! t {
 
 static TEST: AtomicUsize = ATOMIC_USIZE_INIT;
 
+fn debug() {
+    ::std::env::set_var("RUST_BACKTRACE", "1");
+
+    unsafe {
+        let pid = libc::fork();
+        if pid == 0 {
+            println!("@@ Child is running.");
+            return; // we are the child
+        }
+        assert!(pid > 0);
+
+        println!("@@ Watcher is running.");
+
+        let mut status: libc::c_int = 0;
+        libc::waitpid(pid, &mut status, 0);
+
+        println!("@@EXIT@@: {}", status);
+
+        ::std::process::exit(0);
+    }
+}
+
 fn main() {
+    debug();
+
     println!("starting test server");
     let listener = t!(TcpListener::bind("10.0.2.15:12345"));
     println!("listening!");