prepare_tool_cargo: add support for a miri-test mode, and use it in the cargo-miri smoke test and Miri sysroot build

Author: RalfJung

src/bootstrap/src/core/build_steps/run.rs

@@ -121,7 +121,6 @@ impl Step for ReplaceVersionPlaceholder {
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Miri {
-    stage: u32,
     host: TargetSelection,
     target: TargetSelection,
 }
@@ -135,22 +134,17 @@ impl Step for Miri {
     }
 
     fn make_run(run: RunConfig<'_>) {
-        run.builder.ensure(Miri {
-            stage: run.builder.top_stage,
-            host: run.build_triple(),
-            target: run.target,
-        });
+        run.builder.ensure(Miri { host: run.build_triple(), target: run.target });
     }
 
     fn run(self, builder: &Builder<'_>) {
-        let stage = self.stage;
+        let stage = builder.top_stage;
         let host = self.host;
         let target = self.target;
         let compiler = builder.compiler(stage, host);
 
-        let miri =
-            builder.ensure(tool::Miri { compiler, target: self.host, extra_features: Vec::new() });
-        let miri_sysroot = test::Miri::build_miri_sysroot(builder, compiler, &miri, target);
+        let compiler_std = builder.compiler(if stage < 2 { stage + 1 } else { stage }, host);
+        let miri_sysroot = test::Miri::build_miri_sysroot(builder, compiler_std, target);
 
         // # Run miri.
         // Running it via `cargo run` as that figures out the right dylib path.

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

@@ -493,7 +493,6 @@ impl Step for RustDemangler {
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Miri {
-    stage: u32,
     host: TargetSelection,
     target: TargetSelection,
 }
@@ -502,29 +501,21 @@ impl Miri {
     /// Run `cargo miri setup` for the given target, return where the Miri sysroot was put.
     pub fn build_miri_sysroot(
         builder: &Builder<'_>,
-        compiler: Compiler,
-        miri: &Path,
+        compiler_std: Compiler,
         target: TargetSelection,
     ) -> String {
-        let miri_sysroot = builder.out.join(compiler.host.triple).join("miri-sysroot");
-        let mut cargo = tool::prepare_tool_cargo(
+        let miri_sysroot = builder.out.join(compiler_std.host.triple).join("miri-sysroot");
+        let mut cargo = builder::Cargo::new(
             builder,
-            compiler,
-            Mode::ToolRustc,
-            compiler.host,
-            "run",
-            "src/tools/miri/cargo-miri",
-            SourceType::InTree,
-            &[],
+            compiler_std, // this is compiler+1; cargo_miri_cmd will do -1 again
+            Mode::Std,
+            SourceType::Submodule,
+            target,
+            "miri-setup",
         );
-        cargo.add_rustc_lib_path(builder);
-        cargo.arg("--").arg("miri").arg("setup");
-        cargo.arg("--target").arg(target.rustc_target_arg());
 
         // Tell `cargo miri setup` where to find the sources.
         cargo.env("MIRI_LIB_SRC", builder.src.join("library"));
-        // Tell it where to find Miri.
-        cargo.env("MIRI", miri);
         // Tell it where to put the sysroot.
         cargo.env("MIRI_SYSROOT", &miri_sysroot);
         // Debug things.
@@ -533,10 +524,10 @@ impl Miri {
         let mut cargo = Command::from(cargo);
         let _guard = builder.msg(
             Kind::Build,
-            compiler.stage + 1,
+            compiler_std.stage,
             "miri sysroot",
-            compiler.host,
-            compiler.host,
+            compiler_std.host,
+            compiler_std.host,
         );
         builder.run(&mut cargo);
 
@@ -574,16 +565,12 @@ impl Step for Miri {
     }
 
     fn make_run(run: RunConfig<'_>) {
-        run.builder.ensure(Miri {
-            stage: run.builder.top_stage,
-            host: run.build_triple(),
-            target: run.target,
-        });
+        run.builder.ensure(Miri { host: run.build_triple(), target: run.target });
     }
 
     /// Runs `cargo test` for miri.
     fn run(self, builder: &Builder<'_>) {
-        let stage = self.stage;
+        let stage = builder.top_stage;
         let host = self.host;
         let target = self.target;
         let compiler = builder.compiler(stage, host);
@@ -592,18 +579,15 @@ impl Step for Miri {
         let compiler_std = builder.compiler(if stage < 2 { stage + 1 } else { stage }, host);
 
         let miri =
-            builder.ensure(tool::Miri { compiler, target: self.host, extra_features: Vec::new() });
-        let _cargo_miri = builder.ensure(tool::CargoMiri {
-            compiler,
-            target: self.host,
-            extra_features: Vec::new(),
-        });
+            builder.ensure(tool::Miri { compiler, target: host, extra_features: Vec::new() });
+        // the ui tests also assume cargo-miri has been built
+        builder.ensure(tool::CargoMiri { compiler, target: host, extra_features: Vec::new() });
         // The stdlib we need might be at a different stage. And just asking for the
         // sysroot does not seem to populate it, so we do that first.
         builder.ensure(compile::Std::new(compiler_std, host));
         let sysroot = builder.sysroot(compiler_std);
         // We also need a Miri sysroot.
-        let miri_sysroot = Miri::build_miri_sysroot(builder, compiler, &miri, target);
+        let miri_sysroot = Miri::build_miri_sysroot(builder, compiler_std, target);
 
         // # Run `cargo test`.
         let mut cargo = tool::prepare_tool_cargo(
@@ -632,8 +616,8 @@ impl Step for Miri {
         // Set the target.
         cargo.env("MIRI_TEST_TARGET", target.rustc_target_arg());
 
-        // This can NOT be `run_cargo_test` since the Miri test runner
-        // does not understand the flags added by `add_flags_and_try_run_test`.
+        // This can NOT be `run_cargo_test` since Miri's integration tests do not use the usual test
+        // harness and therefore do not understand the flags added by `add_flags_and_try_run_test`.
         let mut cargo = prepare_cargo_test(cargo, &[], &[], "miri", compiler, target, builder);
         {
             let _time = helpers::timeit(builder);
@@ -660,28 +644,20 @@ impl Step for Miri {
         // # Run `cargo miri test`.
         // This is just a smoke test (Miri's own CI invokes this in a bunch of different ways and ensures
         // that we get the desired output), but that is sufficient to make sure that the libtest harness
-        // itself executes properly under Miri.
+        // itself executes properly under Miri, and that all the logic in `cargo-miri` does not explode.
+        // Everything here needs `compiler_std` to be actually testing the Miri in the current stage.
         let mut cargo = tool::prepare_tool_cargo(
             builder,
-            compiler,
-            Mode::ToolRustc,
-            host,
-            "run",
-            "src/tools/miri/cargo-miri",
+            compiler_std,  // this is compiler+1; cargo_miri_cmd will do -1 again
+            Mode::ToolStd, // it's unclear what to use here, we're not building anything just doing a smoke test!
+            target,
+            "miri-test",
+            "src/tools/miri/test-cargo-miri",
             SourceType::Submodule,
             &[],
         );
-        cargo.add_rustc_lib_path(builder);
-        cargo.arg("--").arg("miri").arg("test");
-        if builder.config.locked_deps {
-            cargo.arg("--locked");
-        }
-        cargo
-            .arg("--manifest-path")
-            .arg(builder.src.join("src/tools/miri/test-cargo-miri/Cargo.toml"));
-        cargo.arg("--target").arg(target.rustc_target_arg());
 
-        // `prepare_tool_cargo` sets RUSTDOC to the bootstrap wrapper and RUSTDOC_REAL to a dummy path as this is a "run", not a "test".
+        // `prepare_tool_cargo` sets RUSTDOC to the bootstrap wrapper and RUSTDOC_REAL to a dummy path as this is a "miri", not a "test".
         // Also, we want the rustdoc from the "next" stage for the same reason that we build a std from the next stage.
         // So let's just set that here, and bypass bootstrap's RUSTDOC (just like cargo-miri already ignores bootstrap's RUSTC_WRAPPER).
         if builder.doc_tests != DocTests::No {
@@ -697,10 +673,9 @@ impl Step for Miri {
             }
         }
 
-        // Tell `cargo miri` where to find things.
+        // Tell `cargo miri` where to find the sysroots.
         cargo.env("MIRI_SYSROOT", &miri_sysroot);
         cargo.env("MIRI_HOST_SYSROOT", sysroot);
-        cargo.env("MIRI", &miri);
         // Debug things.
         cargo.env("RUST_BACKTRACE", "1");
 

src/bootstrap/src/core/builder.rs

@@ -1253,6 +1253,28 @@ impl<'a> Builder<'a> {
         cmd
     }
 
+    pub fn cargo_miri_cmd(&self, run_compiler: Compiler) -> Command {
+        assert!(run_compiler.stage > 0);
+        let build_compiler = self.compiler(run_compiler.stage - 1, self.build.build);
+        // Make sure Miri itself is also built
+        let miri = self.ensure(tool::Miri {
+            compiler: build_compiler,
+            target: self.build.build,
+            extra_features: Vec::new(),
+        });
+
+        let cargo_miri = self.ensure(tool::CargoMiri {
+            compiler: build_compiler,
+            target: self.build.build,
+            extra_features: Vec::new(),
+        });
+        let mut cmd = Command::new(cargo_miri);
+        cmd.env("MIRI", &miri);
+        cmd.env("CARGO", &self.initial_cargo);
+        self.add_rustc_lib_path(run_compiler, &mut cmd);
+        cmd
+    }
+
     pub fn rustdoc_cmd(&self, compiler: Compiler) -> Command {
         let mut cmd = Command::new(self.bootstrap_out.join("rustdoc"));
         cmd.env("RUSTC_STAGE", compiler.stage.to_string())
@@ -1296,18 +1318,24 @@ impl<'a> Builder<'a> {
         target: TargetSelection,
         cmd: &str,
     ) -> Command {
-        let mut cargo = if cmd == "clippy" {
-            self.cargo_clippy_cmd(compiler)
+        let mut cargo;
+        if cmd == "clippy" {
+            cargo = self.cargo_clippy_cmd(compiler);
+            cargo.arg(cmd);
+        } else if let Some(subcmd) = cmd.strip_prefix("miri-") {
+            cargo = self.cargo_miri_cmd(compiler);
+            cargo.arg("miri").arg(subcmd);
         } else {
-            Command::new(&self.initial_cargo)
-        };
+            cargo = Command::new(&self.initial_cargo);
+            cargo.arg(cmd);
+        }
 
         // Run cargo from the source root so it can find .cargo/config.
         // This matters when using vendoring and the working directory is outside the repository.
         cargo.current_dir(&self.src);
 
         let out_dir = self.stage_out(compiler, mode);
-        cargo.env("CARGO_TARGET_DIR", &out_dir).arg(cmd);
+        cargo.env("CARGO_TARGET_DIR", &out_dir);
 
         // Found with `rg "init_env_logger\("`. If anyone uses `init_env_logger`
         // from out of tree it shouldn't matter, since x.py is only used for
@@ -1337,7 +1365,8 @@ impl<'a> Builder<'a> {
 
         if self.config.rust_optimize.is_release() {
             // FIXME: cargo bench/install do not accept `--release`
-            if cmd != "bench" && cmd != "install" {
+            // and miri doesn't want it
+            if cmd != "bench" && cmd != "install" && !cmd.starts_with("miri-") {
                 cargo.arg("--release");
             }
         }
@@ -1353,7 +1382,8 @@ impl<'a> Builder<'a> {
     /// Cargo. This cargo will be configured to use `compiler` as the actual
     /// rustc compiler, its output will be scoped by `mode`'s output directory,
     /// it will pass the `--target` flag for the specified `target`, and will be
-    /// executing the Cargo command `cmd`.
+    /// executing the Cargo command `cmd`. `cmd` can be `miri-cmd` for commands
+    /// to be run with Miri.
     fn cargo(
         &self,
         compiler: Compiler,