Rollup merge of #65151 - tmandry:revert-emscripten-upgrade, r=tmandry

Revert #63649 - "Upgrade Emscripten targets to use upstream LLVM backend"

This change caused the runtime of the linux-asmjs builder to nearly double from 2+ hours to about 4 hours, which happens to be the bors timeout. (It made it in barely under 4 hours when it was merged.) This is causing timeouts on all new changes.

This reverts commit 7870050, reversing
changes made to 2e72448.

config.toml.example

@@ -377,7 +377,6 @@
 # but you can also optionally enable the "emscripten" backend for asm.js or
 # make this an empty array (but that probably won't get too far in the
 # bootstrap)
-# FIXME: remove the obsolete emscripten backend option.
 #codegen-backends = ["llvm"]
 
 # This is the name of the directory in which codegen backends will get installed

src/bootstrap/builder.rs

@@ -970,7 +970,6 @@ impl<'a> Builder<'a> {
                 Some("-Wl,-rpath,@loader_path/../lib")
             } else if !target.contains("windows") &&
                       !target.contains("wasm32") &&
-                      !target.contains("emscripten") &&
                       !target.contains("fuchsia") {
                 Some("-Wl,-rpath,$ORIGIN/../lib")
             } else {

src/bootstrap/test.rs

@@ -1047,11 +1047,10 @@ impl Step for Compiletest {
         // Also provide `rust_test_helpers` for the host.
         builder.ensure(native::TestHelpers { target: compiler.host });
 
-        // As well as the target, except for plain wasm32, which can't build it
-        if !target.contains("wasm32") || target.contains("emscripten") {
+        // wasm32 can't build the test helpers
+        if !target.contains("wasm32") {
             builder.ensure(native::TestHelpers { target });
         }
-
         builder.ensure(RemoteCopyLibs { compiler, target });
 
         let mut cmd = builder.tool_cmd(Tool::Compiletest);

src/ci/docker/asmjs/Dockerfile

@@ -11,8 +11,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   cmake \
   sudo \
   gdb \
-  xz-utils \
-  bzip2
+  xz-utils
 
 COPY scripts/emscripten.sh /scripts/
 RUN bash /scripts/emscripten.sh
@@ -21,16 +20,28 @@ COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
 ENV PATH=$PATH:/emsdk-portable
-ENV PATH=$PATH:/emsdk-portable/upstream/emscripten/
-ENV PATH=$PATH:/emsdk-portable/node/12.9.1_64bit/bin/
-ENV BINARYEN_ROOT=/emsdk-portable/upstream/
+ENV PATH=$PATH:/emsdk-portable/clang/e1.38.15_64bit/
+ENV PATH=$PATH:/emsdk-portable/emscripten/1.38.15/
+ENV PATH=$PATH:/emsdk-portable/node/8.9.1_64bit/bin/
+ENV EMSCRIPTEN=/emsdk-portable/emscripten/1.38.15/
+ENV BINARYEN_ROOT=/emsdk-portable/clang/e1.38.15_64bit/binaryen/
 ENV EM_CONFIG=/emsdk-portable/.emscripten
 
 ENV TARGETS=asmjs-unknown-emscripten
 
-ENV SCRIPT python2.7 ../x.py test --target $TARGETS
+ENV RUST_CONFIGURE_ARGS --enable-emscripten --disable-optimize-tests
 
-# This is almost identical to the wasm32-unknown-emscripten target, so
-# running with assertions again is not useful
-ENV NO_DEBUG_ASSERTIONS=1
+ENV SCRIPT python2.7 ../x.py test --target $TARGETS \
+  src/test/ui \
+  src/test/run-fail \
+  src/libstd \
+  src/liballoc \
+  src/libcore
+
+# Debug assertions in rustc are largely covered by other builders, and LLVM
+# assertions cause this builder to slow down by quite a large amount and don't
+# buy us a huge amount over other builders (not sure if we've ever seen an
+# asmjs-specific backend assertion trip), so disable assertions for these
+# tests.
 ENV NO_LLVM_ASSERTIONS=1
+ENV NO_DEBUG_ASSERTIONS=1

src/ci/docker/disabled/wasm32-exp/Dockerfile

@@ -0,0 +1,35 @@
+FROM ubuntu:16.04
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+  g++ \
+  make \
+  file \
+  curl \
+  ca-certificates \
+  python \
+  git \
+  cmake \
+  sudo \
+  gdb \
+  xz-utils \
+  jq \
+  bzip2
+
+# emscripten
+COPY scripts/emscripten-wasm.sh /scripts/
+COPY wasm32-exp/node.sh /usr/local/bin/node
+RUN bash /scripts/emscripten-wasm.sh
+
+# cache
+COPY scripts/sccache.sh /scripts/
+RUN sh /scripts/sccache.sh
+
+# env
+ENV PATH=/wasm-install/emscripten:/wasm-install/bin:$PATH
+ENV EM_CONFIG=/root/.emscripten
+
+ENV TARGETS=wasm32-experimental-emscripten
+
+ENV RUST_CONFIGURE_ARGS --experimental-targets=WebAssembly
+
+ENV SCRIPT python2.7 ../x.py test --target $TARGETS

src/ci/docker/disabled/wasm32-exp/node.sh

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+
+path="$(dirname $1)"
+file="$(basename $1)"
+
+shift
+
+cd "$path"
+exec /node-v8.0.0-linux-x64/bin/node "$file" "$@"

src/ci/docker/disabled/wasm32/Dockerfile

@@ -11,28 +11,22 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   cmake \
   sudo \
   gdb \
-  xz-utils \
-  bzip2
+  xz-utils
 
+# emscripten
 COPY scripts/emscripten.sh /scripts/
 RUN bash /scripts/emscripten.sh
 
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
 ENV PATH=$PATH:/emsdk-portable
-ENV PATH=$PATH:/emsdk-portable/upstream/emscripten/
-ENV PATH=$PATH:/emsdk-portable/node/12.9.1_64bit/bin/
-ENV BINARYEN_ROOT=/emsdk-portable/upstream/
+ENV PATH=$PATH:/emsdk-portable/clang/e1.38.15_64bit/
+ENV PATH=$PATH:/emsdk-portable/emscripten/1.38.15/
+ENV PATH=$PATH:/emsdk-portable/node/8.9.1_64bit/bin/
+ENV EMSCRIPTEN=/emsdk-portable/emscripten/1.38.15/
+ENV BINARYEN_ROOT=/emsdk-portable/clang/e1.38.15_64bit/binaryen/
 ENV EM_CONFIG=/emsdk-portable/.emscripten
 
 ENV TARGETS=wasm32-unknown-emscripten
-
-# FIXME: Re-enable these tests once Cargo stops trying to execute wasms
-ENV SCRIPT python2.7 ../x.py test --target $TARGETS \
-    --exclude src/libcore \
-    --exclude src/liballoc \
-    --exclude src/libproc_macro \
-    --exclude src/libstd \
-    --exclude src/libterm \
-    --exclude src/libtest
+ENV SCRIPT python2.7 ../x.py test --target $TARGETS

src/ci/docker/scripts/emscripten-wasm.sh

@@ -0,0 +1,37 @@
+set -ex
+
+hide_output() {
+  set +x
+  on_err="
+echo ERROR: An error was encountered with the build.
+cat /tmp/build.log
+exit 1
+"
+  trap "$on_err" ERR
+  bash -c "while true; do sleep 30; echo \$(date) - building ...; done" &
+  PING_LOOP_PID=$!
+  $@ &> /tmp/build.log
+  trap - ERR
+  kill $PING_LOOP_PID
+  rm -f /tmp/build.log
+  set -x
+}
+
+# Download last known good emscripten from WebAssembly waterfall
+BUILD=$(curl -fL https://storage.googleapis.com/wasm-llvm/builds/linux/lkgr.json | \
+    jq '.build | tonumber')
+curl -sL https://storage.googleapis.com/wasm-llvm/builds/linux/$BUILD/wasm-binaries.tbz2 | \
+    hide_output tar xvkj
+
+# node 8 is required to run wasm
+cd /
+curl -sL https://nodejs.org/dist/v8.0.0/node-v8.0.0-linux-x64.tar.xz | \
+    tar -xJ
+
+# Make emscripten use wasm-ready node and LLVM tools
+echo "EMSCRIPTEN_ROOT = '/wasm-install/emscripten'" >> /root/.emscripten
+echo "NODE_JS='/usr/local/bin/node'" >> /root/.emscripten
+echo "LLVM_ROOT='/wasm-install/bin'" >> /root/.emscripten
+echo "BINARYEN_ROOT = '/wasm-install'" >> /root/.emscripten
+echo "COMPILER_ENGINE = NODE_JS" >> /root/.emscripten
+echo "JS_ENGINES = [NODE_JS]" >> /root/.emscripten

src/ci/docker/scripts/emscripten.sh

@@ -17,15 +17,20 @@ exit 1
   set -x
 }
 
-git clone https://github.com/emscripten-core/emsdk.git /emsdk-portable
+cd /
+curl -fL https://mozilla-games.s3.amazonaws.com/emscripten/releases/emsdk-portable.tar.gz | \
+    tar -xz
+
 cd /emsdk-portable
-hide_output ./emsdk install 1.38.46-upstream
-./emsdk activate 1.38.46-upstream
+./emsdk update
+hide_output ./emsdk install sdk-1.38.15-64bit
+./emsdk activate sdk-1.38.15-64bit
 
 # Compile and cache libc
 source ./emsdk_env.sh
 echo "main(){}" > a.c
 HOME=/emsdk-portable/ emcc a.c
+HOME=/emsdk-portable/ emcc -s BINARYEN=1 a.c
 rm -f a.*
 
 # Make emsdk usable by any user

src/liballoc/tests/binary_heap.rs

@@ -1,5 +1,10 @@
+use std::cmp;
 use std::collections::BinaryHeap;
 use std::collections::binary_heap::{Drain, PeekMut};
+use std::panic::{self, AssertUnwindSafe};
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+use rand::{thread_rng, seq::SliceRandom};
 
 #[test]
 fn test_iterator() {
@@ -276,15 +281,9 @@ fn assert_covariance() {
 // even if the order may not be correct.
 //
 // Destructors must be called exactly once per element.
-// FIXME: re-enable emscripten once it can unwind again
 #[test]
-#[cfg(not(any(miri, target_os = "emscripten")))] // Miri does not support catching panics
+#[cfg(not(miri))] // Miri does not support catching panics
 fn panic_safe() {
-    use std::cmp;
-    use std::panic::{self, AssertUnwindSafe};
-    use std::sync::atomic::{AtomicUsize, Ordering};
-    use rand::{thread_rng, seq::SliceRandom};
-
     static DROP_COUNTER: AtomicUsize = AtomicUsize::new(0);
 
     #[derive(Eq, PartialEq, Ord, Clone, Debug)]

src/liballoc/tests/str.rs

@@ -483,7 +483,7 @@ mod slice_index {
     }
 
     #[test]
-    #[cfg(not(target_os = "emscripten"))] // hits an OOM
+    #[cfg(not(target_arch = "asmjs"))] // hits an OOM
     #[cfg(not(miri))] // Miri is too slow
     fn simple_big() {
         fn a_million_letter_x() -> String {

src/liballoc/tests/vec.rs

@@ -944,10 +944,8 @@ fn drain_filter_complex() {
     }
 }
 
-// Miri does not support catching panics
-// FIXME: re-enable emscripten once it can unwind again
 #[test]
-#[cfg(not(any(miri, target_os = "emscripten")))]
+#[cfg(not(miri))] // Miri does not support catching panics
 fn drain_filter_consumed_panic() {
     use std::rc::Rc;
     use std::sync::Mutex;
@@ -997,9 +995,8 @@ fn drain_filter_consumed_panic() {
     }
 }
 
-// FIXME: Re-enable emscripten once it can catch panics
 #[test]
-#[cfg(not(any(miri, target_os = "emscripten")))] // Miri does not support catching panics
+#[cfg(not(miri))] // Miri does not support catching panics
 fn drain_filter_unconsumed_panic() {
     use std::rc::Rc;
     use std::sync::Mutex;

src/libcore/ffi.rs

@@ -49,10 +49,8 @@ impl fmt::Debug for c_void {
 /// Basic implementation of a `va_list`.
 // The name is WIP, using `VaListImpl` for now.
 #[cfg(any(all(not(target_arch = "aarch64"), not(target_arch = "powerpc"),
-              not(target_arch = "x86_64")),
+              not(target_arch = "x86_64"), not(target_arch = "asmjs")),
           all(target_arch = "aarch64", target_os = "ios"),
-          target_arch = "wasm32",
-          target_arch = "asmjs",
           windows))]
 #[repr(transparent)]
 #[unstable(feature = "c_variadic",
@@ -69,10 +67,8 @@ pub struct VaListImpl<'f> {
 }
 
 #[cfg(any(all(not(target_arch = "aarch64"), not(target_arch = "powerpc"),
-              not(target_arch = "x86_64")),
+              not(target_arch = "x86_64"), not(target_arch = "asmjs")),
           all(target_arch = "aarch64", target_os = "ios"),
-          target_arch = "wasm32",
-          target_arch = "asmjs",
           windows))]
 #[unstable(feature = "c_variadic",
            reason = "the `c_variadic` feature has not been properly tested on \
@@ -141,6 +137,38 @@ pub struct VaListImpl<'f> {
     _marker: PhantomData<&'f mut &'f c_void>,
 }
 
+/// asm.js ABI implementation of a `va_list`.
+// asm.js uses the PNaCl ABI, which specifies that a `va_list` is
+// an array of 4 32-bit integers, according to the old PNaCl docs at
+// https://web.archive.org/web/20130518054430/https://www.chromium.org/nativeclient/pnacl/bitcode-abi#TOC-Derived-Types
+// and clang does the same in `CreatePNaClABIBuiltinVaListDecl` from `lib/AST/ASTContext.cpp`
+#[cfg(all(target_arch = "asmjs", not(windows)))]
+#[repr(C)]
+#[unstable(feature = "c_variadic",
+           reason = "the `c_variadic` feature has not been properly tested on \
+                     all supported platforms",
+           issue = "44930")]
+#[lang = "va_list"]
+pub struct VaListImpl<'f> {
+    inner: [crate::mem::MaybeUninit<i32>; 4],
+    _marker: PhantomData<&'f mut &'f c_void>,
+}
+
+#[cfg(all(target_arch = "asmjs", not(windows)))]
+#[unstable(feature = "c_variadic",
+           reason = "the `c_variadic` feature has not been properly tested on \
+                     all supported platforms",
+           issue = "44930")]
+impl<'f> fmt::Debug for VaListImpl<'f> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        unsafe {
+            write!(f, "va_list* [{:#x}, {:#x}, {:#x}, {:#x}]",
+                   self.inner[0].read(), self.inner[1].read(),
+                   self.inner[2].read(), self.inner[3].read())
+        }
+    }
+}
+
 /// A wrapper for a `va_list`
 #[repr(transparent)]
 #[derive(Debug)]
@@ -150,29 +178,23 @@ pub struct VaListImpl<'f> {
            issue = "44930")]
 pub struct VaList<'a, 'f: 'a> {
     #[cfg(any(all(not(target_arch = "aarch64"), not(target_arch = "powerpc"),
-                  not(target_arch = "x86_64")),
+                  not(target_arch = "x86_64"), not(target_arch = "asmjs")),
               all(target_arch = "aarch64", target_os = "ios"),
-              target_arch = "wasm32",
-              target_arch = "asmjs",
               windows))]
     inner: VaListImpl<'f>,
 
     #[cfg(all(any(target_arch = "aarch64", target_arch = "powerpc",
-                  target_arch = "x86_64"),
+                  target_arch = "x86_64", target_arch = "asmjs"),
               any(not(target_arch = "aarch64"), not(target_os = "ios")),
-              not(target_arch = "wasm32"),
-              not(target_arch = "asmjs"),
               not(windows)))]
     inner: &'a mut VaListImpl<'f>,
 
     _marker: PhantomData<&'a mut VaListImpl<'f>>,
 }
 
 #[cfg(any(all(not(target_arch = "aarch64"), not(target_arch = "powerpc"),
-              not(target_arch = "x86_64")),
+              not(target_arch = "x86_64"), not(target_arch = "asmjs")),
           all(target_arch = "aarch64", target_os = "ios"),
-          target_arch = "wasm32",
-          target_arch = "asmjs",
           windows))]
 #[unstable(feature = "c_variadic",
            reason = "the `c_variadic` feature has not been properly tested on \
@@ -190,10 +212,8 @@ impl<'f> VaListImpl<'f> {
 }
 
 #[cfg(all(any(target_arch = "aarch64", target_arch = "powerpc",
-              target_arch = "x86_64"),
+              target_arch = "x86_64", target_arch = "asmjs"),
           any(not(target_arch = "aarch64"), not(target_os = "ios")),
-          not(target_arch = "wasm32"),
-          not(target_arch = "asmjs"),
           not(windows)))]
 #[unstable(feature = "c_variadic",
            reason = "the `c_variadic` feature has not been properly tested on \