Add a build script to inform the binary about its profile, and use that in the test suite

Cargo.toml

@@ -5,6 +5,7 @@ license = "MIT/Apache-2.0"
 name = "miri"
 repository = "https://github.com/solson/miri"
 version = "0.1.0"
+build = "build.rs"
 
 [[bin]]
 doc = false

build.rs

@@ -0,0 +1,6 @@
+use std::env;
+
+fn main() {
+    // Forward the profile to the main compilation
+    println!("cargo:rustc-env=PROFILE={}", env::var("PROFILE").unwrap());
+}

tests/compiletest.rs

@@ -13,16 +13,15 @@ macro_rules! eprintln {
     }
 }
 
-#[cfg(debug_assertions)]
-const MIRI_PATH: &str = "target/debug/miri";
-#[cfg(not(debug_assertions))]
-const MIRI_PATH: &str = "target/release/miri";
+fn miri_path() -> String {
+    format!("target/{}/miri", env!("PROFILE"))
+}
 
 fn compile_fail(sysroot: &Path, path: &str, target: &str, host: &str, fullmir: bool) {
     eprintln!("## Running compile-fail tests in {} against miri for target {}", path, target);
     let mut config = compiletest::default_config();
     config.mode = "compile-fail".parse().expect("Invalid mode");
-    config.rustc_path = MIRI_PATH.into();
+    config.rustc_path = miri_path().into();
     if fullmir {
         if host != target {
             // skip fullmir on nonhost
@@ -61,7 +60,7 @@ fn miri_pass(path: &str, target: &str, host: &str, fullmir: bool, opt: bool) {
     config.src_base = PathBuf::from(path);
     config.target = target.to_owned();
     config.host = host.to_owned();
-    config.rustc_path = MIRI_PATH.into();
+    config.rustc_path = miri_path().into();
     let mut flags = Vec::new();
     if fullmir {
         if host != target {