add tests for LinkerFlavorCli options parsing

Author: lqd

compiler/rustc_session/src/lib.rs

@@ -34,6 +34,9 @@ pub mod output;
 
 pub use getopts;
 
+#[cfg(test)]
+mod tests;
+
 /// Requirements for a `StableHashingContext` to be used in this crate.
 /// This is a hack to allow using the `HashStable_Generic` derive macro
 /// instead of implementing everything in `rustc_middle`.

compiler/rustc_session/src/tests.rs

@@ -0,0 +1,55 @@
+use std::str::FromStr;
+
+use crate::config::*;
+use rustc_target::spec::{LinkerFlavor, LldFlavor};
+
+/// When adding enrichments to `-C linker-flavor`, we want to ensure the existing `rustc_target`
+/// `LinkerFlavor`s are still supported as-is: they are option values that can be used on
+/// stable.
+#[test]
+pub fn parse_well_known_linker_flavor() {
+    // All `LinkerFlavor`s are wrapped as a whole, so there's no particular need to be
+    // exhaustive here.
+    assert_eq!(LinkerFlavorCli::from_str("gcc"), Ok(LinkerFlavorCli::WellKnown(LinkerFlavor::Gcc)));
+    assert_eq!(
+        LinkerFlavorCli::from_str("msvc"),
+        Ok(LinkerFlavorCli::WellKnown(LinkerFlavor::Msvc))
+    );
+    assert_eq!(
+        LinkerFlavorCli::from_str("bpf-linker"),
+        Ok(LinkerFlavorCli::WellKnown(LinkerFlavor::BpfLinker))
+    );
+    assert_eq!(
+        LinkerFlavorCli::from_str("lld-link"),
+        Ok(LinkerFlavorCli::WellKnown(LinkerFlavor::Lld(LldFlavor::Link)))
+    );
+    assert_eq!(
+        LinkerFlavorCli::from_str("ld64.lld"),
+        Ok(LinkerFlavorCli::WellKnown(LinkerFlavor::Lld(LldFlavor::Ld64)))
+    );
+
+    // While other invalid values for well-known flavors are already errors
+    assert_eq!(LinkerFlavorCli::from_str("unknown_linker"), Err(()));
+}
+
+/// Enrichments can currently allow for the `gcc` flavor to specify for a given linker to be
+/// used, much like you'd use `-fuse-ld` as a link arg. When using `-C
+/// linker-flavor=gcc:$linker`, the `$linker` will be passed directly to `cc`.
+#[test]
+pub fn parse_gcc_enrichment_linker_flavor() {
+    assert_eq!(
+        LinkerFlavorCli::from_str("gcc:lld"),
+        Ok(LinkerFlavorCli::Gcc { use_ld: "lld".to_string() })
+    );
+    assert_eq!(
+        LinkerFlavorCli::from_str("gcc:gold"),
+        Ok(LinkerFlavorCli::Gcc { use_ld: "gold".to_string() })
+    );
+
+    // No linker actually mentioned
+    assert_eq!(LinkerFlavorCli::from_str("gcc:"), Err(()));
+
+    // Only one `gcc:` separator allowed
+    assert_eq!(LinkerFlavorCli::from_str("gcc:gcc:"), Err(()));
+    assert_eq!(LinkerFlavorCli::from_str("gcc:gcc:linker"), Err(()));
+}