also get library/alloc to test in miri

Author: RalfJung

library/alloc/benches/vec_deque_append.rs

@@ -5,6 +5,11 @@ const WARMUP_N: usize = 100;
 const BENCH_N: usize = 1000;
 
 fn main() {
+    if cfg!(miri) {
+        // Don't benchmark Miri...
+        // (Due to cargo quirks, this gets picked up by `x.py test library/alloc --no-doc`.)
+        return;
+    }
     let a: VecDeque<i32> = (0..VECDEQUE_LEN).collect();
     let b: VecDeque<i32> = (0..VECDEQUE_LEN).collect();
 

library/alloc/src/lib.rs

@@ -72,6 +72,8 @@
     not(test),
     not(any(test, bootstrap)),
     any(not(feature = "miri-test-libstd"), test, doctest),
+    all(feature = "miri-test", not(any(test, doctest))),
+    not(all(feature = "miri-test", not(any(test, doctest)))),
     no_global_oom_handling,
     not(no_global_oom_handling),
     not(no_rc),
@@ -217,6 +219,26 @@
 // from other crates, but since this can only appear for lang items, it doesn't seem worth fixing.
 #![feature(intra_doc_pointers)]
 
+// We want to be able to `cargo miri test` this crate, but that's tricky.
+// We use the `miri-test` feature to indicate that we're running `cargo miri test`, and
+// with that feature we turn this crate into a re-export of the sysroot crate. We only do this when
+// building the crate that will become a dependency, not when doing the actual (doc)test build.
+// See `core/src/lib.rs` for more information.
+#[cfg(all(feature = "miri-test", not(any(test, doctest))))]
+extern crate alloc as realalloc;
+#[cfg(all(feature = "miri-test", not(any(test, doctest))))]
+#[stable(feature = "miri_test", since = "1.0.0")]
+pub use realalloc::*;
+
+// Otherwise, we build the crate as usual. To avoid having to repeat the same `cfg` so many times,
+// we `include!("lib_.rs")` with the main crate contents, and `cfg` the `include!`. However, some
+// macro-related things can't be behind the `include!` so we have to repeat the `cfg` for them.
+
+// Module with internal macros used by other modules (needs to be included before other modules).
+#[cfg(not(all(feature = "miri-test", not(any(test, doctest)))))]
+#[macro_use]
+mod macros;
+
 // Allow testing this library
 #[cfg(test)]
 #[macro_use]
@@ -226,64 +248,5 @@ extern crate test;
 #[cfg(test)]
 mod testing;
 
-// Module with internal macros used by other modules (needs to be included before other modules).
-#[macro_use]
-mod macros;
-
-mod raw_vec;
-
-// Heaps provided for low-level allocation strategies
-
-pub mod alloc;
-
-// Primitive types using the heaps above
-
-// Need to conditionally define the mod from `boxed.rs` to avoid
-// duplicating the lang-items when building in test cfg; but also need
-// to allow code to have `use boxed::Box;` declarations.
-#[cfg(not(test))]
-pub mod boxed;
-#[cfg(test)]
-mod boxed {
-    pub use std::boxed::Box;
-}
-pub mod borrow;
-pub mod collections;
-#[cfg(all(not(no_rc), not(no_sync), not(no_global_oom_handling)))]
-pub mod ffi;
-pub mod fmt;
-#[cfg(not(no_rc))]
-pub mod rc;
-pub mod slice;
-pub mod str;
-pub mod string;
-#[cfg(all(not(no_rc), not(no_sync), target_has_atomic = "ptr"))]
-pub mod sync;
-#[cfg(all(not(no_global_oom_handling), not(no_rc), not(no_sync)))]
-pub mod task;
-#[cfg(test)]
-mod tests;
-pub mod vec;
-
-#[doc(hidden)]
-#[unstable(feature = "liballoc_internals", issue = "none", reason = "implementation detail")]
-pub mod __export {
-    pub use core::format_args;
-}
-
-#[cfg(test)]
-#[allow(dead_code)] // Not used in all configurations
-pub(crate) mod test_helpers {
-    /// Copied from `std::test_helpers::test_rng`, since these tests rely on the
-    /// seed not being the same for every RNG invocation too.
-    pub(crate) fn test_rng() -> rand_xorshift::XorShiftRng {
-        use std::hash::{BuildHasher, Hash, Hasher};
-        let mut hasher = std::hash::RandomState::new().build_hasher();
-        std::panic::Location::caller().hash(&mut hasher);
-        let hc64 = hasher.finish();
-        let seed_vec =
-            hc64.to_le_bytes().into_iter().chain(0u8..8).collect::<crate::vec::Vec<u8>>();
-        let seed: [u8; 16] = seed_vec.as_slice().try_into().unwrap();
-        rand::SeedableRng::from_seed(seed)
-    }
-}
+#[cfg(not(all(feature = "miri-test", not(any(test, doctest)))))]
+include!("lib_.rs");

library/alloc/src/lib_.rs

@@ -0,0 +1,59 @@
+// Vec and VecDeque shared core
+
+mod raw_vec;
+
+// Heaps provided for low-level allocation strategies
+
+pub mod alloc;
+
+// Primitive types using the heaps above
+
+// Need to conditionally define the mod from `boxed.rs` to avoid
+// duplicating the lang-items when building in test cfg; but also need
+// to allow code to have `use boxed::Box;` declarations.
+#[cfg(not(test))]
+pub mod boxed;
+#[cfg(test)]
+mod boxed {
+    pub use std::boxed::Box;
+}
+pub mod borrow;
+pub mod collections;
+#[cfg(all(not(no_rc), not(no_sync), not(no_global_oom_handling)))]
+pub mod ffi;
+pub mod fmt;
+#[cfg(not(no_rc))]
+pub mod rc;
+pub mod slice;
+pub mod str;
+pub mod string;
+#[cfg(all(not(no_rc), not(no_sync), target_has_atomic = "ptr"))]
+pub mod sync;
+#[cfg(all(not(no_global_oom_handling), not(no_rc), not(no_sync)))]
+pub mod task;
+#[cfg(test)]
+mod tests;
+pub mod vec;
+
+#[doc(hidden)]
+#[unstable(feature = "liballoc_internals", issue = "none", reason = "implementation detail")]
+pub mod __export {
+    pub use core::format_args;
+}
+
+#[cfg(test)]
+#[allow(dead_code)] // Not used in all configurations
+pub(crate) mod test_helpers {
+    /// Copied from `std::test_helpers::test_rng`, since these tests rely on the
+    /// seed not being the same for every RNG invocation too.
+    pub(crate) fn test_rng() -> rand_xorshift::XorShiftRng {
+        use std::hash::{BuildHasher, Hash, Hasher};
+        let mut hasher = std::hash::RandomState::new().build_hasher();
+        std::panic::Location::caller().hash(&mut hasher);
+        let hc64 = hasher.finish();
+        let seed_vec =
+            hc64.to_le_bytes().into_iter().chain(0u8..8).collect::<crate::vec::Vec<u8>>();
+        let seed: [u8; 16] = seed_vec.as_slice().try_into().unwrap();
+        rand::SeedableRng::from_seed(seed)
+    }
+}

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

@@ -2618,7 +2618,9 @@ impl Step for Crate {
                 std::process::exit(1);
             }
 
-            // Prepare sysroot
+            // Prepare sysroots
+            builder.ensure(compile::Std::new(compiler, compiler.host));
+            let sysroot = builder.sysroot(compiler);
             let miri_sysroot = Miri::build_miri_sysroot(builder, compiler, target);
 
             // Build `cargo miri test` command
@@ -2631,6 +2633,7 @@ impl Step for Crate {
                 "miri-test",
             );
             cargo.env("MIRI_SYSROOT", &miri_sysroot);
+            cargo.env("MIRI_HOST_SYSROOT", &sysroot);
             // See `Miri` tests for why
             if builder.doc_tests != DocTests::No {
                 cargo.env("RUSTDOC", builder.rustdoc(compiler));