Add CI in Intel's instruction emulator (rust-lang#113)

This commit adds a new builder on CI for running tests in Intel's own emulator
and also adds an assertion that on this emulator no tests are skipped due to
missing CPU features by accident.

Closes rust-lang#92

Author: alexcrichton

Diff for: .travis.yml

@@ -8,6 +8,7 @@ matrix:
     - env: TARGET=i586-unknown-linux-gnu
     - env: TARGET=i686-unknown-linux-gnu
     - env: TARGET=x86_64-unknown-linux-gnu NO_ADD=1
+    - env: TARGET=x86_64-unknown-linux-gnu-emulated NO_ADD=1 STDSIMD_TEST_EVERYTHING=1
     - env: TARGET=arm-unknown-linux-gnueabihf
     - env: TARGET=armv7-unknown-linux-gnueabihf
     - env: TARGET=aarch64-unknown-linux-gnu

Diff for: ci/docker/x86_64-unknown-linux-gnu-emulated/Dockerfile

@@ -0,0 +1,13 @@
+FROM ubuntu:17.04
+RUN apt-get update && apt-get install -y --no-install-recommends \
+  gcc \
+  libc6-dev \
+  file \
+  make \
+  ca-certificates \
+  curl \
+  bzip2
+
+RUN curl https://s3-us-west-1.amazonaws.com/rust-lang-ci2/rust-ci-mirror/sde-external-8.9.0-2017-08-06-lin.tar.bz2 | \
+  tar xjf -
+ENV CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_RUNNER="/sde-external-8.9.0-2017-08-06-lin/sde64 --"

Diff for: ci/run-docker.sh

@@ -7,20 +7,23 @@ run() {
     echo $1
     docker build -t stdsimd ci/docker/$1
     mkdir -p target
+    target=$(echo $1 | sed 's/-emulated//')
     docker run \
       --user `id -u`:`id -g` \
       --rm \
       --init \
       --volume $HOME/.cargo:/cargo \
       --env CARGO_HOME=/cargo \
       --volume `rustc --print sysroot`:/rust:ro \
-      --env TARGET=$1 \
+      --env TARGET=$target \
+      --env STDSIMD_TEST_EVERYTHING \
       --volume `pwd`:/checkout:ro \
       --volume `pwd`/target:/checkout/target \
       --workdir /checkout \
+      --privileged \
       stdsimd \
       bash \
-      -c 'PATH=$PATH:/rust/bin exec ci/run.sh $1'
+      -c 'PATH=$PATH:/rust/bin exec ci/run.sh'
 }
 
 if [ -z "$1" ]; then

Diff for: stdsimd-test/simd-test-macro/src/lib.rs

@@ -51,6 +51,8 @@ pub fn simd_test(attr: proc_macro::TokenStream,
         fn #name() {
             if cfg_feature_enabled!(#target_feature) {
                 return unsafe { #name() };
+            } else {
+                ::stdsimd_test::assert_skip_test_ok(stringify!(#name));
             }
 
             #[target_feature = #enable_feature]

Diff for: stdsimd-test/src/lib.rs

@@ -294,3 +294,10 @@ pub fn assert(fnptr: usize, fnname: &str, expected: &str) {
         panic!("too many instructions in the disassembly");
     }
 }
+
+pub fn assert_skip_test_ok(name: &str) {
+    if env::var("STDSIMD_TEST_EVERYTHING").is_err() {
+        return
+    }
+    panic!("skipped test `{}` when it shouldn't be skipped", name);
+}