Run Miri and mir-opt tests without a target linker

Author: saethlin

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -733,6 +733,9 @@ fn link_natively<'a>(
     codegen_results: &CodegenResults,
     tmpdir: &Path,
 ) -> Result<(), ErrorGuaranteed> {
+    if std::env::var_os("RUSTC_SKIP_LINKER").is_some() {
+        return Ok(());
+    }
     info!("preparing {:?} to {:?}", crate_type, out_filename);
     let (linker_path, flavor) = linker_and_flavor(sess);
     let self_contained_components = self_contained_components(sess, crate_type);

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

@@ -46,6 +46,7 @@ pub struct Std {
     /// but we need to use the downloaded copy of std for linking to rustdoc. Allow this to be overriden by `builder.ensure` from other steps.
     force_recompile: bool,
     extra_rust_args: &'static [&'static str],
+    is_for_mir_opt_tests: bool,
 }
 
 impl Std {
@@ -56,6 +57,7 @@ impl Std {
             crates: Default::default(),
             force_recompile: false,
             extra_rust_args: &[],
+            is_for_mir_opt_tests: false,
         }
     }
 
@@ -66,6 +68,22 @@ impl Std {
             crates: Default::default(),
             force_recompile: true,
             extra_rust_args: &[],
+            is_for_mir_opt_tests: false,
+        }
+    }
+
+    pub fn new_for_mir_opt_tests(compiler: Compiler, target: TargetSelection) -> Self {
+        Self {
+            target,
+            compiler,
+            crates: INTERNER.intern_list(vec![
+                "core".to_string(),
+                "alloc".to_string(),
+                "std".to_string(),
+            ]),
+            force_recompile: false,
+            extra_rust_args: &[],
+            is_for_mir_opt_tests: true,
         }
     }
 
@@ -80,6 +98,7 @@ impl Std {
             crates: Default::default(),
             force_recompile: false,
             extra_rust_args,
+            is_for_mir_opt_tests: false,
         }
     }
 }
@@ -109,6 +128,7 @@ impl Step for Std {
             crates,
             force_recompile: false,
             extra_rust_args: &[],
+            is_for_mir_opt_tests: false,
         });
     }
 
@@ -219,6 +239,9 @@ impl Step for Std {
         for rustflag in self.extra_rust_args.into_iter() {
             cargo.rustflag(rustflag);
         }
+        if self.is_for_mir_opt_tests {
+            cargo.env("RUSTC_SKIP_LINKER", "1");
+        }
 
         let _guard = builder.msg(
             Kind::Build,

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

@@ -1611,16 +1611,23 @@ NOTE: if you're sure you want to do this, please open an issue as to why. In the
                 .ensure(dist::DebuggerScripts { sysroot: builder.sysroot(compiler), host: target });
         }
 
-        builder.ensure(compile::Std::new(compiler, target));
+        if suite == "mir-opt" {
+            builder.ensure(compile::Std::new_for_mir_opt_tests(compiler, target));
+        } else {
+            builder.ensure(compile::Std::new(compiler, target));
+        }
+
         // ensure that `libproc_macro` is available on the host.
         builder.ensure(compile::Std::new(compiler, compiler.host));
 
         // Also provide `rust_test_helpers` for the host.
         builder.ensure(TestHelpers { target: compiler.host });
 
-        // As well as the target, except for plain wasm32, which can't build it
-        if !target.contains("wasm") || target.contains("emscripten") {
-            builder.ensure(TestHelpers { target });
+        if suite != "mir-opt" {
+            // As well as the target, except for plain wasm32, which can't build it
+            if !target.contains("wasm") || target.contains("emscripten") {
+                builder.ensure(TestHelpers { target });
+            }
         }
 
         builder.ensure(RemoteCopyLibs { compiler, target });
@@ -1749,11 +1756,13 @@ NOTE: if you're sure you want to do this, please open an issue as to why. In the
             cmd.arg("--host-rustcflags").arg(flag);
         }
 
-        let mut targetflags = flags;
-        targetflags.push(format!("-Lnative={}", builder.test_helpers_out(target).display()));
-        targetflags.extend(linker_flags(builder, compiler.host, LldThreads::No));
-        for flag in targetflags {
-            cmd.arg("--target-rustcflags").arg(flag);
+        if mode != "mir-opt" {
+            let mut targetflags = flags;
+            targetflags.push(format!("-Lnative={}", builder.test_helpers_out(target).display()));
+            targetflags.extend(linker_flags(builder, compiler.host, LldThreads::No));
+            for flag in targetflags {
+                cmd.arg("--target-rustcflags").arg(flag);
+            }
         }
 
         cmd.arg("--python").arg(builder.python());

src/bootstrap/src/core/sanity.rs

@@ -62,9 +62,23 @@ impl Finder {
 }
 
 pub fn check(build: &mut Build) {
-    let skip_target_sanity =
+    let mut skip_target_sanity =
         env::var_os("BOOTSTRAP_SKIP_TARGET_SANITY").is_some_and(|s| s == "1" || s == "true");
 
+    let skipped_paths = [OsStr::new("mir-opt"), OsStr::new("miri")];
+
+    // Skip target sanity checks when we are doing anything with mir-opt tests or Miri
+    for path in &build.config.paths {
+        if path.components.any(|component| skipped_paths.contains(&component.as_os_str())) {
+            skip_target_sanity = true;
+            break;
+
+        }
+    }
+    if [std::path::PathBuf::from("mir-opt")].as_slice() == build.config.paths {
+        skip_target_sanity = true;
+    }
+
     let path = env::var_os("PATH").unwrap_or_default();
     // On Windows, quotes are invalid characters for filename paths, and if
     // one is present as part of the PATH then that can lead to the system

src/ci/docker/host-x86_64/x86_64-gnu-tools/checktools.sh

@@ -37,7 +37,6 @@ else
 fi
 # We natively run this script on x86_64-unknown-linux-gnu and x86_64-pc-windows-msvc.
 # Also cover some other targets via cross-testing, in particular all tier 1 targets.
-export BOOTSTRAP_SKIP_TARGET_SANITY=1 # we don't need `cc` for these targets
 case $HOST_TARGET in
   x86_64-unknown-linux-gnu)
     # Only this branch runs in PR CI.
@@ -62,4 +61,3 @@ case $HOST_TARGET in
     exit 1
     ;;
 esac
-unset BOOTSTRAP_SKIP_TARGET_SANITY

tests/mir-opt/remove_never_const.rs

@@ -3,9 +3,6 @@
 // consts in codegen. We also have tests for this that catches the error, see
 // tests/ui/consts/const-eval/index-out-of-bounds-never-type.rs.
 
-// Force generation of optimized mir for functions that do not reach codegen.
-// compile-flags: --emit mir,link
-
 #![feature(never_type)]
 
 struct PrintName<T>(T);