use RUSTC_WRAPPER for the cargo hook

.travis.yml

@@ -12,51 +12,22 @@ os:
 dist: xenial
 
 before_script:
-# install extra stuff for cross-compilation
+# Linux: install extra stuff for cross-compilation
 - if [[ "$TRAVIS_OS_NAME" == linux ]]; then sudo apt update && sudo apt install gcc-multilib; fi
-# macOS weirdness (https://github.com/travis-ci/travis-ci/issues/6307, https://github.com/travis-ci/travis-ci/issues/10165)
-- if [[ "$TRAVIS_OS_NAME" == osx ]]; then rvm get stable; fi
 # Compute the rust version we use. We do not use "language: rust" to have more control here.
 - |
   if [[ "$TRAVIS_EVENT_TYPE" == cron ]]; then
     RUST_TOOLCHAIN=nightly
   else
     RUST_TOOLCHAIN=$(cat rust-version)
   fi
-- |
-  if [ "$TRAVIS_OS_NAME" == osx ]; then
-    export MIRI_SYSROOT_BASE=~/Library/Caches/miri.miri.miri/
-  else
-    export MIRI_SYSROOT_BASE=~/.cache/miri/
-  fi
-- |
-  if [[ "$TRAVIS_OS_NAME" == osx ]]; then
-    FOREIGN_TARGET=i686-apple-darwin
-  else
-    FOREIGN_TARGET=i686-unknown-linux-gnu
-  fi
 # install Rust
 - curl https://build.travis-ci.org/files/rustup-init.sh -sSf | sh -s -- -y --default-toolchain "$RUST_TOOLCHAIN"
 - export PATH=$HOME/.cargo/bin:$PATH
 - rustc --version
 
 script:
-- set -e
-- |
-  # Build and install miri
-  cargo build --release --all-features --all-targets &&
-  cargo install --all-features --force --path .
-- |
-  # Get ourselves a MIR-full libstd for the host and a foreign architecture
-  cargo miri setup &&
-  cargo miri setup --target "$FOREIGN_TARGET"
-- |
-  # Test miri with full MIR, on the host and other architectures
-  MIRI_SYSROOT=$MIRI_SYSROOT_BASE/HOST cargo test --release --all-features &&
-  MIRI_SYSROOT=$MIRI_SYSROOT_BASE MIRI_TARGET=$FOREIGN_TARGET cargo test --release --all-features
-- |
-  # Test cargo integration
-  (cd test-cargo-miri && MIRI_SYSROOT=$MIRI_SYSROOT_BASE/HOST ./run-test.py)
+- ./travis.sh
 
 notifications:
   email:

src/bin/cargo-miri.rs

@@ -305,8 +305,8 @@ fn main() {
                 _ => {}
             }
         }
-    } else {
-        // This arm is executed when cargo-miri runs `cargo rustc` with the `RUSTC` env var set to itself:
+    } else if let Some("rustc") = std::env::args().nth(1).as_ref().map(AsRef::as_ref) {
+        // This arm is executed when cargo-miri runs `cargo rustc` with the `RUSTC_WRAPPER` env var set to itself:
         // Dependencies get dispatched to rustc, the final test/binary to miri.
 
         let home = option_env!("RUSTUP_HOME").or(option_env!("MULTIRUST_HOME"));
@@ -332,11 +332,11 @@ fn main() {
 
         // this conditional check for the --sysroot flag is there so users can call `cargo-miri` directly
         // without having to pass --sysroot or anything
+        let rustc_args = std::env::args().skip(2);
         let mut args: Vec<String> = if std::env::args().any(|s| s == "--sysroot") {
-            std::env::args().skip(1).collect()
+            rustc_args.collect()
         } else {
-            std::env::args()
-                .skip(1)
+            rustc_args
                 .chain(Some("--sysroot".to_owned()))
                 .chain(Some(sys_root))
                 .collect()
@@ -365,6 +365,8 @@ fn main() {
             Err(ref e) if miri_enabled => panic!("error during miri run: {:?}", e),
             Err(ref e) => panic!("error during rustc call: {:?}", e),
         }
+    } else {
+        show_error(format!("Must be called with either `miri` or `rustc` as first argument."))
     }
 }
 
@@ -389,7 +391,7 @@ where
     let path = std::env::current_exe().expect("current executable path invalid");
     let exit_status = Command::new("cargo")
         .args(&args)
-        .env("RUSTC", path)
+        .env("RUSTC_WRAPPER", path)
         .spawn()
         .expect("could not run cargo")
         .wait()

tests/compiletest.rs

@@ -3,7 +3,7 @@
 #![test_runner(test_runner)]
 
 use std::slice::SliceConcatExt;
-use std::path::{PathBuf, Path};
+use std::path::PathBuf;
 use std::env;
 
 use compiletest_rs as compiletest;

travis.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+set -e
+
+# Determine configuration
+if [ "$TRAVIS_OS_NAME" == osx ]; then
+  export MIRI_SYSROOT_BASE=~/Library/Caches/miri.miri.miri/
+  FOREIGN_TARGET=i686-apple-darwin
+else
+  export MIRI_SYSROOT_BASE=~/.cache/miri/
+  FOREIGN_TARGET=i686-unknown-linux-gnu
+fi
+
+echo "Build and install miri"
+cargo build --release --all-features --all-targets &&
+cargo install --all-features --force --path .
+echo
+
+echo "Get ourselves a MIR-full libstd for the host and a foreign architecture"
+cargo miri setup &&
+cargo miri setup --target "$FOREIGN_TARGET"
+echo
+
+echo "Test miri with full MIR, on the host and other architectures"
+MIRI_SYSROOT=$MIRI_SYSROOT_BASE/HOST cargo test --release --all-features &&
+MIRI_SYSROOT=$MIRI_SYSROOT_BASE MIRI_TARGET=$FOREIGN_TARGET cargo test --release --all-features
+echo
+
+echo "Test cargo integration"
+(cd test-cargo-miri && MIRI_SYSROOT=$MIRI_SYSROOT_BASE/HOST ./run-test.py)
+echo