Auto merge of #113026 - jieyouxu:run-make-v2, r=bjorn3

Introduce `run-make` V2 infrastructure, a `run_make_support` library and port over 2 tests as example

## Preface

See [issue #40713: Switch run-make tests from Makefiles to rust](#40713) for more context.

## Basic Description of `run-make` V2

`run-make` V2 aims to eliminate the dependency on `make` and `Makefile`s for building `run-make`-style tests. Makefiles are replaced by *recipes* (`rmake.rs`). The current implementation runs `run-make` V2 tests in 3 steps:

1. We build the support library `run_make_support` which the `rmake.rs` recipes depend on as a tool lib.
2. We build the recipe `rmake.rs` and link in the support library.
3. We run the recipe to build and run the tests.

`rmake.rs` is basically a replacement for `Makefile`, and allows running arbitrary Rust code. The support library is built using cargo, and so can depend on external crates if desired.

The infrastructure implemented by this PR is very barebones, and is the minimally required infrastructure needed to build, run and pass the two example `run-make` tests ported over to the new infrastructure.

### Example `run-make` V2 test

```rs
// ignore-tidy-linelength

extern crate run_make_support;

use std::path::PathBuf;

use run_make_support::{aux_build, rustc};

fn main() {
    aux_build()
        .arg("--emit=metadata")
        .arg("stable.rs")
        .run();
    let mut stable_path = PathBuf::from(env!("TMPDIR"));
    stable_path.push("libstable.rmeta");
    let output = rustc()
        .arg("--emit=metadata")
        .arg("--extern")
        .arg(&format!("stable={}", &stable_path.to_string_lossy()))
        .arg("main.rs")
        .run();

    let stderr = String::from_utf8_lossy(&output.stderr);
    let version = include_str!(concat!(env!("S"), "/src/version"));
    let expected_string = format!("stable since {}", version.trim());
    assert!(stderr.contains(&expected_string));
}
```

## Follow Up Work

- [ ] Adjust rustc-dev-guide docs

Cargo.lock

@@ -3274,6 +3274,10 @@ dependencies = [
  "serde_json",
 ]
 
+[[package]]
+name = "run_make_support"
+version = "0.0.0"
+
 [[package]]
 name = "rust-demangler"
 version = "0.0.1"

Cargo.toml

@@ -10,6 +10,7 @@ members = [
   "src/tools/clippy",
   "src/tools/clippy/clippy_dev",
   "src/tools/compiletest",
+  "src/tools/run-make-support",
   "src/tools/error_index_generator",
   "src/tools/linkchecker",
   "src/tools/lint-docs",

src/bootstrap/src/core/build_steps/test.rs

@@ -1327,6 +1327,52 @@ macro_rules! coverage_test_alias {
     };
 }
 
+#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq, Ord, PartialOrd)]
+pub struct RunMakeSupport {
+    pub compiler: Compiler,
+    pub target: TargetSelection,
+}
+
+impl Step for RunMakeSupport {
+    type Output = PathBuf;
+    const DEFAULT: bool = true;
+
+    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
+        run.never()
+    }
+
+    fn make_run(run: RunConfig<'_>) {
+        let compiler = run.builder.compiler(run.builder.top_stage, run.build_triple());
+        run.builder.ensure(RunMakeSupport { compiler, target: run.build_triple() });
+    }
+
+    fn run(self, builder: &Builder<'_>) -> PathBuf {
+        builder.ensure(compile::Std::new(self.compiler, self.target));
+
+        let cargo = tool::prepare_tool_cargo(
+            builder,
+            self.compiler,
+            Mode::ToolStd,
+            self.target,
+            "build",
+            "src/tools/run-make-support",
+            SourceType::InTree,
+            &[],
+        );
+
+        let mut cargo = Command::from(cargo);
+        builder.run(&mut cargo);
+
+        let lib_name = "librun_make_support.rlib";
+        let lib = builder.tools_dir(self.compiler).join(&lib_name);
+
+        let cargo_out =
+            builder.cargo_out(self.compiler, Mode::ToolStd, self.target).join(&lib_name);
+        builder.copy(&cargo_out, &lib);
+        lib
+    }
+}
+
 default_test!(Ui { path: "tests/ui", mode: "ui", suite: "ui" });
 
 default_test!(RunPassValgrind {
@@ -1361,7 +1407,40 @@ host_test!(RustdocJson { path: "tests/rustdoc-json", mode: "rustdoc-json", suite
 
 host_test!(Pretty { path: "tests/pretty", mode: "pretty", suite: "pretty" });
 
-default_test!(RunMake { path: "tests/run-make", mode: "run-make", suite: "run-make" });
+// Special-handling is needed for `run-make`, so don't use `default_test` for defining `RunMake`
+// tests.
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+pub struct RunMake {
+    pub compiler: Compiler,
+    pub target: TargetSelection,
+}
+
+impl Step for RunMake {
+    type Output = ();
+    const DEFAULT: bool = true;
+    const ONLY_HOSTS: bool = false;
+
+    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
+        run.suite_path("tests/run-make")
+    }
+
+    fn make_run(run: RunConfig<'_>) {
+        let compiler = run.builder.compiler(run.builder.top_stage, run.build_triple());
+        run.builder.ensure(RunMakeSupport { compiler, target: run.build_triple() });
+        run.builder.ensure(RunMake { compiler, target: run.target });
+    }
+
+    fn run(self, builder: &Builder<'_>) {
+        builder.ensure(Compiletest {
+            compiler: self.compiler,
+            target: self.target,
+            mode: "run-make",
+            suite: "run-make",
+            path: "tests/run-make",
+            compare_mode: None,
+        });
+    }
+}
 
 host_test!(RunMakeFullDeps {
     path: "tests/run-make-fulldeps",

src/tools/compiletest/src/lib.rs

@@ -655,13 +655,21 @@ fn collect_tests_from_dir(
         return Ok(());
     }
 
-    if config.mode == Mode::RunMake && dir.join("Makefile").exists() {
-        let paths = TestPaths {
-            file: dir.to_path_buf(),
-            relative_dir: relative_dir_path.parent().unwrap().to_path_buf(),
-        };
-        tests.extend(make_test(config, cache, &paths, inputs, poisoned));
-        return Ok(());
+    if config.mode == Mode::RunMake {
+        if dir.join("Makefile").exists() && dir.join("rmake.rs").exists() {
+            return Err(io::Error::other(
+                "run-make tests cannot have both `Makefile` and `rmake.rs`",
+            ));
+        }
+
+        if dir.join("Makefile").exists() || dir.join("rmake.rs").exists() {
+            let paths = TestPaths {
+                file: dir.to_path_buf(),
+                relative_dir: relative_dir_path.parent().unwrap().to_path_buf(),
+            };
+            tests.extend(make_test(config, cache, &paths, inputs, poisoned));
+            return Ok(());
+        }
     }
 
     // If we find a test foo/bar.rs, we have to build the
@@ -733,8 +741,17 @@ fn make_test(
     poisoned: &mut bool,
 ) -> Vec<test::TestDescAndFn> {
     let test_path = if config.mode == Mode::RunMake {
-        // Parse directives in the Makefile
-        testpaths.file.join("Makefile")
+        if testpaths.file.join("rmake.rs").exists() && testpaths.file.join("Makefile").exists() {
+            panic!("run-make tests cannot have both `rmake.rs` and `Makefile`");
+        }
+
+        if testpaths.file.join("rmake.rs").exists() {
+            // Parse directives in rmake.rs.
+            testpaths.file.join("rmake.rs")
+        } else {
+            // Parse directives in the Makefile.
+            testpaths.file.join("Makefile")
+        }
     } else {
         PathBuf::from(&testpaths.file)
     };