extend run-make test runner with some helper functions

src/tools/run-make-support/src/lib.rs

@@ -10,7 +10,7 @@ pub use object;
 pub use wasmparser;
 
 pub use run::{run, run_fail};
-pub use rustc::{aux_build, rustc, Rustc};
+pub use rustc::{aux_build, rustc, ErrorFormat, Rustc};
 pub use rustdoc::{bare_rustdoc, rustdoc, Rustdoc};
 
 /// Path of `TMPDIR` (a temporary build directory, not under `/tmp`).

src/tools/run-make-support/src/rustc.rs

@@ -27,6 +27,13 @@ fn setup_common() -> Command {
     cmd
 }
 
+#[derive(Copy, Clone)]
+pub enum ErrorFormat {
+    Human,
+    Json,
+    Short,
+}
+
 impl Rustc {
     // `rustc` invocation constructor methods
 
@@ -85,6 +92,35 @@ impl Rustc {
         self
     }
 
+    /// Specify number of codegen units
+    pub fn codegen_units(&mut self, units: usize) -> &mut Self {
+        self.cmd.arg(format!("-Ccodegen-units={units}"));
+        self
+    }
+
+    /// Specify directory path used for incremental cache
+    pub fn incremental(&mut self, path: impl AsRef<Path>) -> &mut Self {
+        let path = path.as_ref().to_string_lossy();
+        self.cmd.arg(format!("-Cincremental={}", path));
+        self
+    }
+
+    /// Specify error format to use
+    pub fn error_format(&mut self, format: ErrorFormat) -> &mut Self {
+        self.cmd.arg(match format {
+            ErrorFormat::Human => "--error-format=human",
+            ErrorFormat::Json => "--error-format=json",
+            ErrorFormat::Short => "--error-format=Short",
+        });
+        self
+    }
+
+    /// Specify json messages printed by the compiler
+    pub fn json(&mut self, items: &str) -> &mut Self {
+        self.cmd.arg(format!("--json={items}"));
+        self
+    }
+
     /// Specify target triple.
     pub fn target(&mut self, target: &str) -> &mut Self {
         assert!(!target.contains(char::is_whitespace), "target triple cannot contain spaces");