Run tests for all specified targets

Currently cargo-miri uses the first target specified in the command
line. However, when multiple targets are specified in a `cargo build`
invocation, cargo will build for all of them.

Miri should match this behaviour to reduce surprises.

Fixes: #3460

Author: Mandragorian

src/tools/miri/cargo-miri/src/phases.rs

@@ -104,9 +104,17 @@ pub fn phase_cargo_miri(mut args: impl Iterator<Item = String>) {
             miri_for_host()
         )
     });
-    let host = &rustc_version.host;
-    let target = get_arg_flag_value("--target");
-    let target = target.as_ref().unwrap_or(host);
+    let mut targets = get_arg_flag_values("--target").collect::<Vec<_>>();
+    // If `targets` is empty, we need to add a `--target $HOST` flag ourselves, and also ensure
+    // that the host target is indeed setup.
+    let target_flag = if targets.is_empty() {
+        let host = &rustc_version.host;
+        targets.push(host.clone());
+        Some(host)
+    } else {
+        // We don't need to add a `--target` flag, we just forward the user's flags.
+        None
+    };
 
     // If cleaning the target directory & sysroot cache,
     // delete them then exit. There is no reason to setup a new
@@ -118,8 +126,11 @@ pub fn phase_cargo_miri(mut args: impl Iterator<Item = String>) {
         return;
     }
 
-    // We always setup.
-    let miri_sysroot = setup(&subcommand, target, &rustc_version, verbose, quiet);
+    for target in &targets {
+        // We always setup.
+        setup(&subcommand, target.as_str(), &rustc_version, verbose, quiet);
+    }
+    let miri_sysroot = get_sysroot_dir();
 
     // Invoke actual cargo for the job, but with different flags.
     // We re-use `cargo test` and `cargo run`, which makes target and binary handling very easy but
@@ -155,10 +166,9 @@ pub fn phase_cargo_miri(mut args: impl Iterator<Item = String>) {
     // This is needed to make the `target.runner` settings do something,
     // and it later helps us detect which crates are proc-macro/build-script
     // (host crates) and which crates are needed for the program itself.
-    if get_arg_flag_value("--target").is_none() {
-        // No target given. Explicitly pick the host.
+    if let Some(target_flag) = target_flag {
         cmd.arg("--target");
-        cmd.arg(host);
+        cmd.arg(target_flag);
     }
 
     // Set ourselves as runner for al binaries invoked by cargo.

src/tools/miri/ci/ci.sh

@@ -41,9 +41,11 @@ function run_tests {
   if [ -n "${TEST_TARGET-}" ]; then
     begingroup "Testing foreign architecture $TEST_TARGET"
     TARGET_FLAG="--target $TEST_TARGET"
+    MULTI_TARGET_FLAG=""
   else
     begingroup "Testing host architecture"
     TARGET_FLAG=""
+    MULTI_TARGET_FLAG="--multi-target"
   fi
 
   ## ui test suite
@@ -93,7 +95,7 @@ function run_tests {
     echo 'build.rustc-wrapper = "thisdoesnotexist"' > .cargo/config.toml
   fi
   # Run the actual test
-  time ${PYTHON} test-cargo-miri/run-test.py $TARGET_FLAG
+  time ${PYTHON} test-cargo-miri/run-test.py $TARGET_FLAG $MULTI_TARGET_FLAG
   # Clean up
   unset RUSTC MIRI
   rm -rf .cargo

src/tools/miri/test-cargo-miri/run-test.py

@@ -22,12 +22,17 @@ def fail(msg):
     print("\nTEST FAIL: {}".format(msg))
     sys.exit(1)
 
-def cargo_miri(cmd, quiet = True):
+def cargo_miri(cmd, quiet = True, targets = None):
     args = ["cargo", "miri", cmd] + CARGO_EXTRA_FLAGS
     if quiet:
         args += ["-q"]
-    if ARGS.target:
+
+    if targets is not None:
+        for target in targets:
+            args.extend(("--target", target))
+    elif ARGS.target is not None:
         args += ["--target", ARGS.target]
+
     return args
 
 def normalize_stdout(str):
@@ -186,10 +191,21 @@ def test_cargo_miri_test():
         default_ref, "test.stderr-empty.ref",
         env={'MIRIFLAGS': "-Zmiri-permissive-provenance"},
     )
+    if ARGS.multi_target:
+        test_cargo_miri_multi_target()
+
+
+def test_cargo_miri_multi_target():
+    test("`cargo miri test` (multiple targets)",
+        cargo_miri("test", targets = ["aarch64-unknown-linux-gnu", "s390x-unknown-linux-gnu"]),
+        "test.multiple_targets.stdout.ref", "test.stderr-empty.ref",
+        env={'MIRIFLAGS': "-Zmiri-permissive-provenance"},
+    )
 
 args_parser = argparse.ArgumentParser(description='`cargo miri` testing')
 args_parser.add_argument('--target', help='the target to test')
 args_parser.add_argument('--bless', help='bless the reference files', action='store_true')
+args_parser.add_argument('--multi-target', help='run tests related to multiple targets', action='store_true')
 ARGS = args_parser.parse_args()
 
 os.chdir(os.path.dirname(os.path.realpath(__file__)))

src/tools/miri/test-cargo-miri/test.multiple_targets.stdout.ref

@@ -0,0 +1,22 @@
+
+running 2 tests
+..
+test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in $TIME
+
+
+running 2 tests
+..
+test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in $TIME
+
+imported main
+imported main
+
+running 6 tests
+...i..
+test result: ok. 5 passed; 0 failed; 1 ignored; 0 measured; 0 filtered out; finished in $TIME
+
+
+running 6 tests
+...i..
+test result: ok. 5 passed; 0 failed; 1 ignored; 0 measured; 0 filtered out; finished in $TIME
+