Add test flag for running a test only on the host

Author: oli-obk

ui_test/README.md

@@ -25,8 +25,10 @@ their command specifies, or the test will fail without even being run.
 
 * `//@ignore-XXX` avoids running the test on targets whose triple contains `XXX`
     * `XXX` can also be one of `64bit`, `32bit` or `16bit`
+    * `XXX` can also be `on-host`, which will only run the test during cross compilation testing.
 * `//@only-XXX` avoids running the test on targets whose triple **does not** contain `XXX`
     * `XXX` can also be one of `64bit`, `32bit` or `16bit`
+    * `XXX` can also be `on-host`, which will not run the test during cross compilation testing
 * `//@stderr-per-bitwidth` produces one stderr file per bitwidth, as they may differ significantly sometimes
 * `//@error-pattern: XXX` make sure the stderr output contains `XXX`
 * `//@revisions: XXX YYY` runs the test once for each space separated name in the list

ui_test/src/lib.rs

@@ -109,7 +109,7 @@ pub fn run_tests(config: Config) -> Result<()> {
                     }
                     let comments = Comments::parse_file(&path)?;
                     // Ignore file if only/ignore rules do (not) apply
-                    if !test_file_conditions(&comments, &target) {
+                    if !test_file_conditions(&comments, &target, &config) {
                         ignored.fetch_add(1, Ordering::Relaxed);
                         eprintln!(
                             "{} ... {}",
@@ -499,19 +499,20 @@ fn output_path(path: &Path, comments: &Comments, kind: String, target: &str) ->
     path.with_extension(kind)
 }
 
-fn test_condition(condition: &Condition, target: &str) -> bool {
+fn test_condition(condition: &Condition, target: &str, config: &Config) -> bool {
     match condition {
         Condition::Bitwidth(bits) => get_pointer_width(target) == *bits,
         Condition::Target(t) => target.contains(t),
+        Condition::OnHost => config.target.is_none(),
     }
 }
 
 /// Returns whether according to the in-file conditions, this file should be run.
-fn test_file_conditions(comments: &Comments, target: &str) -> bool {
-    if comments.ignore.iter().any(|c| test_condition(c, target)) {
+fn test_file_conditions(comments: &Comments, target: &str, config: &Config) -> bool {
+    if comments.ignore.iter().any(|c| test_condition(c, target, config)) {
         return false;
     }
-    comments.only.iter().all(|c| test_condition(c, target))
+    comments.only.iter().all(|c| test_condition(c, target, config))
 }
 
 // Taken 1:1 from compiletest-rs

ui_test/src/parser.rs

@@ -43,6 +43,8 @@ pub(crate) enum Condition {
     Target(String),
     /// Tests that the bitwidth is the given one.
     Bitwidth(u8),
+    /// Tests that the target is the host.
+    OnHost,
 }
 
 #[derive(Debug, Clone)]
@@ -64,6 +66,10 @@ pub(crate) struct ErrorMatch {
 
 impl Condition {
     fn parse(c: &str) -> Self {
+        match c {
+            "on-host" => return Condition::OnHost,
+            _ => {}
+        }
         if let Some(bits) = c.strip_suffix("bit") {
             let bits: u8 = bits.parse().expect(
                 "ignore/only filter ending in 'bit' must be of the form 'Nbit' for some integer N",