CI: run test suite in Miri (#456)

.github/workflows/ci.yml

@@ -123,6 +123,13 @@ jobs:
         run: rustup component add rust-src
       - name: ASAN / TSAN
         run: . ci/tsan.sh
+  miri:
+    name: miri
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Miri
+        run: ci/miri.sh
 
   # Loom
   loom:

ci/miri.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+set -e
+
+MIRI_NIGHTLY=nightly-$(curl -s https://rust-lang.github.io/rustup-components-history/x86_64-unknown-linux-gnu/miri)
+echo "Installing latest nightly with Miri: $MIRI_NIGHTLY"
+rustup set profile minimal
+rustup default "$MIRI_NIGHTLY"
+rustup component add miri
+
+cargo miri test
+cargo miri test --target mips64-unknown-linux-gnuabi64

tests/test_bytes.rs

@@ -461,6 +461,7 @@ fn reserve_allocates_at_least_original_capacity() {
 }
 
 #[test]
+#[cfg_attr(miri, ignore)] // Miri is too slow
 fn reserve_max_original_capacity_value() {
     const SIZE: usize = 128 * 1024;
 
@@ -608,15 +609,15 @@ fn advance_past_len() {
 
 #[test]
 // Only run these tests on little endian systems. CI uses qemu for testing
-// little endian... and qemu doesn't really support threading all that well.
+// big endian... and qemu doesn't really support threading all that well.
-#[cfg(target_endian = "little")]
+#[cfg(any(miri, target_endian = "little"))]
 fn stress() {
     // Tests promoting a buffer from a vec -> shared in a concurrent situation
     use std::sync::{Arc, Barrier};
     use std::thread;
 
     const THREADS: usize = 8;
-    const ITERS: usize = 1_000;
+    const ITERS: usize = if cfg!(miri) { 100 } else { 1_000 };
 
     for i in 0..ITERS {
         let data = [i as u8; 256];

tests/test_bytes_odd_alloc.rs

@@ -1,6 +1,8 @@
 //! Test using `Bytes` with an allocator that hands out "odd" pointers for
 //! vectors (pointers where the LSB is set).
 
+#![cfg(not(miri))] // Miri does not support custom allocators (also, Miri is "odd" by default with 50% chance)
+
 use std::alloc::{GlobalAlloc, Layout, System};
 use std::ptr;