Auto merge of #36339 - brson:emscripten-new, r=alexcrichton

Working asmjs and wasm targets

This patch set results in a working standard library for the asmjs-unknown-emscripten and wasm32-unknown-emscripten targets. It is based on the work of @badboy and @rschulman.

It does a few things:

- Updates LLVM with the emscripten [fastcomp](https://github.com/rust-lang/llvm/pull/50) patches, which include the pnacl IR legalizer and the asm.js backend. This patch is thought not to have any significant effect on existing targets.
- Teaches rustbuild to correctly link C code with emscripten
- Updates gcc-rs to work correctly with emscripten
- Teaches rustbuild to run crate tests for emscripten with node
- Modifies Thread::new to return an error on emscripten, to facilitate debugging a common failure mode
- Modifies libtest to run in single-threaded mode for emscripten
- Ignores a host of tests that don't work yet, mostly dealing with threads and I/O
- Updates libc with wasm32 definitions (presently the same as asmjs)
- Adds a wasm32-unknown-emscripten target that feeds the output of LLVM's asmjs backend through emcc to generate wasm

Notes and caveats:

- This is only known to work with `--enable-rustbuild`.
- The wasm32 target can't be tested correctly yet because of issues in compiletest and limitations in node https://github.com/kripken/emscripten/issues/4542, but hello.rs does seem to work when run on node via the binaryen interpreter
- This requires an up to date installation of the emscripten sdk from its incoming branch
- Unwinding is very broken
- When enabling the emscripten targets jemalloc is disabled for all targets, which results in test failures for the host

Next steps are to fix the jemalloc issue, start building the two emscripten targets on the auto builders, then start producing nightlies.

https://github.com/rust-lang/rust/issues/36317 tracks work on this.

Fixes https://github.com/rust-lang/rust/issues/36515
Fixes https://github.com/rust-lang/rust/issues/36515
Fixes https://github.com/rust-lang/rust/issues/36356

29 files changed, 76 insertions, 30 deletions

diff --git a/src/libstd/env.rs b/src/libstd/env.rs
index 5171fbdf03e..76a2f93c162 100644
--- a/src/libstd/env.rs
+++ b/src/libstd/env.rs
@@ -892,7 +892,18 @@ mod os {
     pub const EXE_EXTENSION: &'static str = "pexe";
 }
 
-#[cfg(target_os = "emscripten")]
+#[cfg(all(target_os = "emscripten", target_arch = "asmjs"))]
+mod os {
+    pub const FAMILY: &'static str = "unix";
+    pub const OS: &'static str = "emscripten";
+    pub const DLL_PREFIX: &'static str = "lib";
+    pub const DLL_SUFFIX: &'static str = ".so";
+    pub const DLL_EXTENSION: &'static str = "so";
+    pub const EXE_SUFFIX: &'static str = ".js";
+    pub const EXE_EXTENSION: &'static str = "js";
+}
+
+#[cfg(all(target_os = "emscripten", target_arch = "wasm32"))]
 mod os {
     pub const FAMILY: &'static str = "unix";
     pub const OS: &'static str = "emscripten";
@@ -969,6 +980,11 @@ mod arch {
     pub const ARCH: &'static str = "asmjs";
 }
 
+#[cfg(target_arch = "wasm32")]
+mod arch {
+    pub const ARCH: &'static str = "wasm32";
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -1017,6 +1033,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(target_os = "emscripten", ignore)]
     fn test_var_big() {
         let mut s = "".to_string();
         let mut i = 0;
@@ -1030,6 +1047,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(target_os = "emscripten", ignore)]
     fn test_self_exe_path() {
         let path = current_exe();
         assert!(path.is_ok());
@@ -1040,6 +1058,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(target_os = "emscripten", ignore)]
     fn test_env_set_get_huge() {
         let n = make_rand_name();
         let s = repeat("x").take(10000).collect::<String>();
diff --git a/src/libstd/fs.rs b/src/libstd/fs.rs
index 576198564db..2f2969b110d 100644
--- a/src/libstd/fs.rs
+++ b/src/libstd/fs.rs
@@ -1686,7 +1686,7 @@ impl AsInnerMut<fs_imp::DirBuilder> for DirBuilder {
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 mod tests {
     use io::prelude::*;
 
diff --git a/src/libstd/io/buffered.rs b/src/libstd/io/buffered.rs
index 4ff8c6ac128..21a0cc1fb3b 100644
--- a/src/libstd/io/buffered.rs
+++ b/src/libstd/io/buffered.rs
@@ -1107,6 +1107,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(target_os = "emscripten", ignore)]
     fn panic_in_write_doesnt_flush_in_drop() {
         static WRITES: AtomicUsize = AtomicUsize::new(0);
 
diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index e308a2d8e03..3becc0a0c9e 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -1757,6 +1757,7 @@ mod tests {
     use super::repeat;
 
     #[test]
+    #[cfg_attr(target_os = "emscripten", ignore)]
     fn read_until() {
         let mut buf = Cursor::new(&b"12"[..]);
         let mut v = Vec::new();
@@ -1967,6 +1968,7 @@ mod tests {
     }
 
     #[bench]
+    #[cfg_attr(target_os = "emscripten", ignore)]
     fn bench_read_to_end(b: &mut test::Bencher) {
         b.iter(|| {
             let mut lr = repeat(1).take(10000000);
diff --git a/src/libstd/io/stdio.rs b/src/libstd/io/stdio.rs
index 9a782e95f6e..6421595a009 100644
--- a/src/libstd/io/stdio.rs
+++ b/src/libstd/io/stdio.rs
@@ -593,11 +593,11 @@ impl<'a> Write for StderrLock<'a> {
                      with a more general mechanism",
            issue = "0")]
 #[doc(hidden)]
-pub fn set_panic(sink: Box<Write + Send>) -> Option<Box<Write + Send>> {
+pub fn set_panic(sink: Option<Box<Write + Send>>) -> Option<Box<Write + Send>> {
     use panicking::LOCAL_STDERR;
     use mem;
     LOCAL_STDERR.with(move |slot| {
-        mem::replace(&mut *slot.borrow_mut(), Some(sink))
+        mem::replace(&mut *slot.borrow_mut(), sink)
     }).and_then(|mut s| {
         let _ = s.flush();
         Some(s)
@@ -617,10 +617,10 @@ pub fn set_panic(sink: Box<Write + Send>) -> Option<Box<Write + Send>> {
                      with a more general mechanism",
            issue = "0")]
 #[doc(hidden)]
-pub fn set_print(sink: Box<Write + Send>) -> Option<Box<Write + Send>> {
+pub fn set_print(sink: Option<Box<Write + Send>>) -> Option<Box<Write + Send>> {
     use mem;
     LOCAL_STDOUT.with(move |slot| {
-        mem::replace(&mut *slot.borrow_mut(), Some(sink))
+        mem::replace(&mut *slot.borrow_mut(), sink)
     }).and_then(|mut s| {
         let _ = s.flush();
         Some(s)
@@ -668,6 +668,7 @@ mod tests {
     use super::*;
 
     #[test]
+    #[cfg_attr(target_os = "emscripten", ignore)]
     fn panic_doesnt_poison() {
         thread::spawn(|| {
             let _a = stdin();
diff --git a/src/libstd/net/addr.rs b/src/libstd/net/addr.rs
index d0b59b42c17..58daa7dbf8d 100644
--- a/src/libstd/net/addr.rs
+++ b/src/libstd/net/addr.rs
@@ -519,7 +519,7 @@ impl<'a, T: ToSocketAddrs + ?Sized> ToSocketAddrs for &'a T {
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 mod tests {
     use net::*;
     use net::test::{tsa, sa6, sa4};
diff --git a/src/libstd/net/ip.rs b/src/libstd/net/ip.rs
index 05ef559422f..ba2cd70e0d7 100644
--- a/src/libstd/net/ip.rs
+++ b/src/libstd/net/ip.rs
@@ -669,7 +669,7 @@ impl From<[u8; 16]> for Ipv6Addr {
 }
 
 // Tests for this module
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 mod tests {
     use net::*;
     use net::Ipv6MulticastScope::*;
diff --git a/src/libstd/net/mod.rs b/src/libstd/net/mod.rs
index ad2fe3c1c0d..7dd0e30df03 100644
--- a/src/libstd/net/mod.rs
+++ b/src/libstd/net/mod.rs
@@ -31,7 +31,8 @@ mod addr;
 mod tcp;
 mod udp;
 mod parser;
-#[cfg(test)] mod test;
+#[cfg(all(test, not(target_os = "emscripten")))]
+mod test;
 
 /// Possible values which can be passed to the [`shutdown`] method of
 /// [`TcpStream`].
diff --git a/src/libstd/net/tcp.rs b/src/libstd/net/tcp.rs
index 3c5f07c3e33..0e7c5b06713 100644
--- a/src/libstd/net/tcp.rs
+++ b/src/libstd/net/tcp.rs
@@ -428,7 +428,7 @@ impl fmt::Debug for TcpListener {
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 mod tests {
     use io::ErrorKind;
     use io::prelude::*;
diff --git a/src/libstd/net/udp.rs b/src/libstd/net/udp.rs
index 781f026c12c..c03ac496adb 100644
--- a/src/libstd/net/udp.rs
+++ b/src/libstd/net/udp.rs
@@ -353,7 +353,7 @@ impl fmt::Debug for UdpSocket {
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 mod tests {
     use io::ErrorKind;
     use net::*;
diff --git a/src/libstd/os/linux/raw.rs b/src/libstd/os/linux/raw.rs
index 1c19e58818d..e6a95bc831f 100644
--- a/src/libstd/os/linux/raw.rs
+++ b/src/libstd/os/linux/raw.rs
@@ -34,7 +34,8 @@ pub use self::arch::{off_t, ino_t, nlink_t, blksize_t, blkcnt_t, stat, time_t};
           target_arch = "le32",
           target_arch = "powerpc",
           target_arch = "arm",
-          target_arch = "asmjs"))]
+          target_arch = "asmjs",
+          target_arch = "wasm32"))]
 mod arch {
     use os::raw::{c_long, c_short, c_uint};
 
diff --git a/src/libstd/process.rs b/src/libstd/process.rs
index 674b0009537..9d21a76e81b 100644
--- a/src/libstd/process.rs
+++ b/src/libstd/process.rs
@@ -825,7 +825,7 @@ pub fn exit(code: i32) -> ! {
     ::sys::os::exit(code)
 }
 
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 mod tests {
     use io::prelude::*;
 
diff --git a/src/libstd/rand/mod.rs b/src/libstd/rand/mod.rs
index 3f14fcd239f..69cd37651d5 100644
--- a/src/libstd/rand/mod.rs
+++ b/src/libstd/rand/mod.rs
@@ -242,6 +242,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(target_os = "emscripten", ignore)]
     fn test_os_rng_tasks() {
 
         let mut txs = vec!();
diff --git a/src/libstd/sync/barrier.rs b/src/libstd/sync/barrier.rs
index ac0f400379e..f46eab68484 100644
--- a/src/libstd/sync/barrier.rs
+++ b/src/libstd/sync/barrier.rs
@@ -118,6 +118,7 @@ mod tests {
     use thread;
 
     #[test]
+    #[cfg_attr(target_os = "emscripten", ignore)]
     fn test_barrier() {
         const N: usize = 10;
 
diff --git a/src/libstd/sync/condvar.rs b/src/libstd/sync/condvar.rs
index 3db8b05b954..a983ae716a4 100644
--- a/src/libstd/sync/condvar.rs
+++ b/src/libstd/sync/condvar.rs
@@ -270,6 +270,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(target_os = "emscripten", ignore)]
     fn notify_one() {
         let m = Arc::new(Mutex::new(()));
         let m2 = m.clone();
@@ -286,6 +287,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(target_os = "emscripten", ignore)]
     fn notify_all() {
         const N: usize = 10;
 
@@ -322,6 +324,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg_attr(target_os = "emscripten", ignore)]
     fn wait_timeout_ms() {
         let m = Arc::new(Mutex::new(()));
         let m2 = m.clone();
@@ -343,6 +346,7 @@ mod tests {
 
     #[test]
     #[should_panic]
+    #[cfg_attr(target_os = "emscripten", ignore)]
     fn two_mutexes() {
         let m = Arc::new(Mutex::new(()));
         let m2 = m.clone();
diff --git a/src/libstd/sync/mpsc/mod.rs b/src/libstd/sync/mpsc/mod.rs
index 3d9f81413dc..d9c14ef2f77 100644
--- a/src/libstd/sync/mpsc/mod.rs
+++ b/src/libstd/sync/mpsc/mod.rs
@@ -1268,7 +1268,7 @@ impl error::Error for TryRecvError {
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 mod tests {
     use env;
     use super::*;
@@ -1942,7 +1942,7 @@ mod tests {
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 mod sync_tests {
     use env;
     use thread;
diff --git a/src/libstd/sync/mpsc/mpsc_queue.rs b/src/libstd/sync/mpsc/mpsc_queue.rs
index d926043fbbc..8d80f942ff7 100644
--- a/src/libstd/sync/mpsc/mpsc_queue.rs
+++ b/src/libstd/sync/mpsc/mpsc_queue.rs
@@ -146,7 +146,7 @@ impl<T> Drop for Queue<T> {
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 mod tests {
     use sync::mpsc::channel;
     use super::{Queue, Data, Empty, Inconsistent};
diff --git a/src/libstd/sync/mpsc/select.rs b/src/libstd/sync/mpsc/select.rs
index 51b08bd75c4..91896e1ab85 100644
--- a/src/libstd/sync/mpsc/select.rs
+++ b/src/libstd/sync/mpsc/select.rs
@@ -366,7 +366,7 @@ impl<'rx, T:Send+'rx> fmt::Debug for Handle<'rx, T> {
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 #[allow(unused_imports)]
 mod tests {
     use thread;
diff --git a/src/libstd/sync/mpsc/spsc_queue.rs b/src/libstd/sync/mpsc/spsc_queue.rs
index 724d7b1be73..5858e4b6ddb 100644
--- a/src/libstd/sync/mpsc/spsc_queue.rs
+++ b/src/libstd/sync/mpsc/spsc_queue.rs
@@ -231,7 +231,7 @@ impl<T> Drop for Queue<T> {
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 mod tests {
     use sync::Arc;
     use super::Queue;
diff --git a/src/libstd/sync/mutex.rs b/src/libstd/sync/mutex.rs
index 098a3e44258..812724c7a16 100644
--- a/src/libstd/sync/mutex.rs
+++ b/src/libstd/sync/mutex.rs
@@ -352,7 +352,7 @@ pub fn guard_poison<'a, T: ?Sized>(guard: &MutexGuard<'a, T>) -> &'a poison::Fla
     &guard.__lock.poison
 }
 
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 mod tests {
     use sync::mpsc::channel;
     use sync::{Arc, Mutex, Condvar};
diff --git a/src/libstd/sync/once.rs b/src/libstd/sync/once.rs
index 86d2986959c..ad9d0b37544 100644
--- a/src/libstd/sync/once.rs
+++ b/src/libstd/sync/once.rs
@@ -367,7 +367,7 @@ impl OnceState {
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 mod tests {
     use panic;
     use sync::mpsc::channel;
diff --git a/src/libstd/sync/rwlock.rs b/src/libstd/sync/rwlock.rs
index 7f053c6704b..48ecae185f9 100644
--- a/src/libstd/sync/rwlock.rs
+++ b/src/libstd/sync/rwlock.rs
@@ -380,7 +380,7 @@ impl<'a, T: ?Sized> Drop for RwLockWriteGuard<'a, T> {
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 mod tests {
     #![allow(deprecated)] // rand
 
diff --git a/src/libstd/sys/common/io.rs b/src/libstd/sys/common/io.rs
index 3cd70eddb85..47cec4ef5c2 100644
--- a/src/libstd/sys/common/io.rs
+++ b/src/libstd/sys/common/io.rs
@@ -50,7 +50,7 @@ pub unsafe fn read_to_end_uninitialized(r: &mut Read, buf: &mut Vec<u8>) -> io::
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 pub mod test {
     use path::{Path, PathBuf};
     use env;
@@ -165,6 +165,7 @@ mod tests {
     }
 
     #[bench]
+    #[cfg_attr(target_os = "emscripten", ignore)]
     fn bench_uninitialized(b: &mut ::test::Bencher) {
         b.iter(|| {
             let mut lr = repeat(1).take(10000000);
diff --git a/src/libstd/sys/common/remutex.rs b/src/libstd/sys/common/remutex.rs
index cbdeaad7f6b..4d0407ccf6c 100644
--- a/src/libstd/sys/common/remutex.rs
+++ b/src/libstd/sys/common/remutex.rs
@@ -156,7 +156,7 @@ impl<'a, T> Drop for ReentrantMutexGuard<'a, T> {
 }
 
 
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 mod tests {
     use sys_common::remutex::{ReentrantMutex, ReentrantMutexGuard};
     use cell::RefCell;
diff --git a/src/libstd/sys/unix/ext/net.rs b/src/libstd/sys/unix/ext/net.rs
index 3f93fce1935..40fe24cf10e 100644
--- a/src/libstd/sys/unix/ext/net.rs
+++ b/src/libstd/sys/unix/ext/net.rs
@@ -786,7 +786,7 @@ impl IntoRawFd for UnixDatagram {
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 mod test {
     use thread;
     use io;
diff --git a/src/libstd/sys/unix/process.rs b/src/libstd/sys/unix/process.rs
index 50014f51f6c..dafc11d9cc8 100644
--- a/src/libstd/sys/unix/process.rs
+++ b/src/libstd/sys/unix/process.rs
@@ -369,7 +369,7 @@ impl Command {
         }
 
         // NaCl has no signal support.
-        if cfg!(not(target_os = "nacl")) {
+        if cfg!(not(any(target_os = "nacl", target_os = "emscripten"))) {
             // Reset signal handling so the child process starts in a
             // standardized state. libstd ignores SIGPIPE, and signal-handling
             // libraries often set a mask. Child processes inherit ignored
@@ -589,7 +589,7 @@ impl Process {
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 mod tests {
     use super::*;
 
diff --git a/src/libstd/sys/unix/thread.rs b/src/libstd/sys/unix/thread.rs
index 980ef01f549..1e879117f73 100644
--- a/src/libstd/sys/unix/thread.rs
+++ b/src/libstd/sys/unix/thread.rs
@@ -29,6 +29,20 @@ pub struct Thread {
 unsafe impl Send for Thread {}
 unsafe impl Sync for Thread {}
 
+// The pthread_attr_setstacksize symbol doesn't exist in the emscripten libc,
+// so we have to not link to it to satisfy emcc's ERROR_ON_UNDEFINED_SYMBOLS.
+#[cfg(not(target_os = "emscripten"))]
+unsafe fn pthread_attr_setstacksize(attr: *mut libc::pthread_attr_t,
+                                    stack_size: libc::size_t) -> libc::c_int {
+    libc::pthread_attr_setstacksize(attr, stack_size)
+}
+
+#[cfg(target_os = "emscripten")]
+unsafe fn pthread_attr_setstacksize(_attr: *mut libc::pthread_attr_t,
+                                    _stack_size: libc::size_t) -> libc::c_int {
+    panic!()
+}
+
 impl Thread {
     pub unsafe fn new<'a>(stack: usize, p: Box<FnBox() + 'a>)
                           -> io::Result<Thread> {
@@ -38,8 +52,8 @@ impl Thread {
         assert_eq!(libc::pthread_attr_init(&mut attr), 0);
 
         let stack_size = cmp::max(stack, min_stack_size(&attr));
-        match libc::pthread_attr_setstacksize(&mut attr,
-                                              stack_size as libc::size_t) {
+        match pthread_attr_setstacksize(&mut attr,
+                                        stack_size as libc::size_t) {
             0 => {}
             n => {
                 assert_eq!(n, libc::EINVAL);
diff --git a/src/libstd/thread/local.rs b/src/libstd/thread/local.rs
index c44dee49f14..a333a7d967d 100644
--- a/src/libstd/thread/local.rs
+++ b/src/libstd/thread/local.rs
@@ -524,7 +524,7 @@ pub mod os {
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 mod tests {
     use sync::mpsc::{channel, Sender};
     use cell::{Cell, UnsafeCell};
diff --git a/src/libstd/thread/mod.rs b/src/libstd/thread/mod.rs
index a634c8f77a4..901ff98fcb3 100644
--- a/src/libstd/thread/mod.rs
+++ b/src/libstd/thread/mod.rs
@@ -741,7 +741,7 @@ fn _assert_sync_and_send() {
 // Tests
 ////////////////////////////////////////////////////////////////////////////////
 
-#[cfg(test)]
+#[cfg(all(test, not(target_os = "emscripten")))]
 mod tests {
     use any::Any;
     use sync::mpsc::{channel, Sender};