Rollup merge of rust-lang#113026 - jieyouxu:run-make-v2, r=bjorn3

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

See [issue rust-lang#40713: Switch run-make tests from Makefiles to rust](rust-lang#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 dylib.
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.

### Planned Changes

- [x] Get rid of the builder style patterns in `rmake_support` and instead use something like

    ```rust
    let output = rustc!(scx, "--cfg x -Cprefer-dynamic -Csymbol-mangling-version=legacy -
    Zunstable-options");
    ```
    as per Nils' suggestion. This can probably use something like `xshell`.
- [x] Make `run_make_support` into a proper crate so it can have external dependencies like `xshell`.
- [x] Instead of having an entire alternative directory `run-make-v2`, change how V2 tests are collected based on presence of `rmake.rs` recipe file. This should ease migration and prevent git history from being messed up by big moves.

### Disclaimer

The current implementation is very much a **very very rough prototype** just to get the 2 example tests working. I would appreciate any feedback on the design and implementation.

Cargo.lock

@@ -3258,6 +3258,13 @@ dependencies = [
  "serde_json",
 ]
 
+[[package]]
+name = "run_make_support"
+version = "0.0.0"
+dependencies = [
+ "shell-words",
+]
+
 [[package]]
 name = "rust-demangler"
 version = "0.0.1"
@@ -4968,6 +4975,12 @@ version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "45bb67a18fa91266cc7807181f62f9178a6873bfad7dc788c42e6430db40184f"
 
+[[package]]
+name = "shell-words"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "24188a676b6ae68c3b2cb3a01be17fbf7240ce009799bb56d5b1409051e78fde"
+
 [[package]]
 name = "shlex"
 version = "1.1.0"

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

@@ -26,6 +26,7 @@ use crate::core::config::flags::get_completion;
 use crate::core::config::flags::Subcommand;
 use crate::core::config::TargetSelection;
 use crate::utils::cache::{Interned, INTERNER};
+use crate::utils::dylib::shared_lib_name;
 use crate::utils::exec::BootstrapCommand;
 use crate::utils::helpers::{
     self, add_link_lib_path, add_rustdoc_cargo_linker_args, dylib_path, dylib_path_var,
@@ -1326,6 +1327,53 @@ 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.target });
+    }
+
+    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);
+        cargo.env("RUSTFLAGS", "-C prefer-dynamic");
+        builder.run(&mut cargo);
+
+        let lib_name = shared_lib_name("run_make_support", &self.target.to_string());
+        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 {
@@ -1360,7 +1408,40 @@ 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.target });
+        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/bootstrap/src/utils/dylib.rs

@@ -38,3 +38,16 @@ pub fn exe(name: &str, target: &str) -> String {
         name.to_string()
     }
 }
+
+/// Given a shared library called `name`, return the filename for the
+/// shared library for a particular target.
+#[allow(dead_code)]
+pub fn shared_lib_name(name: &str, target: &str) -> String {
+    if target.contains("windows") {
+        format!("lib{name}.dll")
+    } else if target.contains("apple") {
+        format!("lib{name}.dylib")
+    } else {
+        format!("lib{name}.so")
+    }
+}

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
@@ -731,8 +739,17 @@ 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)
     };