Add step metadata and a simple test for codegen backends

Author: Kobzol

src/bootstrap/src/core/build_steps/compile.rs

@@ -1706,6 +1706,13 @@ impl Step for CodegenBackend {
         let codegen_backend = codegen_backend.to_str().unwrap();
         t!(stamp.add_stamp(codegen_backend).write());
     }
+
+    fn metadata(&self) -> Option<StepMetadata> {
+        Some(
+            StepMetadata::build(&format!("rustc_codegen_{}", self.backend), self.target)
+                .built_by(self.compiler),
+        )
+    }
 }
 
 /// Creates the `codegen-backends` folder for a compiler that's about to be

src/bootstrap/src/core/builder/mod.rs

@@ -142,7 +142,7 @@ pub trait Step: 'static + Clone + Debug + PartialEq + Eq + Hash {
 #[allow(unused)]
 #[derive(Debug, PartialEq, Eq)]
 pub struct StepMetadata {
-    name: &'static str,
+    name: String,
     kind: Kind,
     target: TargetSelection,
     built_by: Option<Compiler>,
@@ -152,28 +152,28 @@ pub struct StepMetadata {
 }
 
 impl StepMetadata {
-    pub fn build(name: &'static str, target: TargetSelection) -> Self {
+    pub fn build(name: &str, target: TargetSelection) -> Self {
         Self::new(name, target, Kind::Build)
     }
 
-    pub fn check(name: &'static str, target: TargetSelection) -> Self {
+    pub fn check(name: &str, target: TargetSelection) -> Self {
         Self::new(name, target, Kind::Check)
     }
 
-    pub fn doc(name: &'static str, target: TargetSelection) -> Self {
+    pub fn doc(name: &str, target: TargetSelection) -> Self {
         Self::new(name, target, Kind::Doc)
     }
 
-    pub fn dist(name: &'static str, target: TargetSelection) -> Self {
+    pub fn dist(name: &str, target: TargetSelection) -> Self {
         Self::new(name, target, Kind::Dist)
     }
 
-    pub fn test(name: &'static str, target: TargetSelection) -> Self {
+    pub fn test(name: &str, target: TargetSelection) -> Self {
         Self::new(name, target, Kind::Test)
     }
 
-    fn new(name: &'static str, target: TargetSelection, kind: Kind) -> Self {
-        Self { name, kind, target, built_by: None, stage: None, metadata: None }
+    fn new(name: &str, target: TargetSelection, kind: Kind) -> Self {
+        Self { name: name.to_string(), kind, target, built_by: None, stage: None, metadata: None }
     }
 
     pub fn built_by(mut self, compiler: Compiler) -> Self {

src/bootstrap/src/core/builder/tests.rs

@@ -718,6 +718,26 @@ mod snapshot {
         ");
     }
 
+    #[test]
+    fn build_compiler_codegen_backend() {
+        let ctx = TestCtx::new();
+        insta::assert_snapshot!(
+            ctx
+                .config("build")
+                .args(&["--set", "rust.codegen-backends=['llvm', 'cranelift']"])
+                .render_steps(), @r"
+        [build] llvm <host>
+        [build] rustc 0 <host> -> rustc 1 <host>
+        [build] rustc 0 <host> -> rustc_codegen_cranelift 1 <host>
+        [build] rustc 1 <host> -> std 1 <host>
+        [build] rustc 1 <host> -> std 1 <host>
+        [build] rustc 1 <host> -> rustc 2 <host>
+        [build] rustc 1 <host> -> rustc_codegen_cranelift 2 <host>
+        [build] rustdoc 1 <host>
+        "
+        );
+    }
+
     #[test]
     fn build_compiler_tools() {
         let ctx = TestCtx::new();