lib.miri.rs appraoch

Author: RalfJung

library/alloc/Cargo.toml

@@ -36,7 +36,5 @@ compiler-builtins-c = ["compiler_builtins/c"]
 compiler-builtins-no-asm = ["compiler_builtins/no-asm"]
 compiler-builtins-mangled-names = ["compiler_builtins/mangled-names"]
 compiler-builtins-weak-intrinsics = ["compiler_builtins/weak-intrinsics"]
-# Empty the crate so Miri can run tests
-miri-test = ["core/miri-test"]
 # Make panics and failed asserts immediately abort without formatting any message
 panic_immediate_abort = []

library/alloc/src/lib.miri.rs

@@ -0,0 +1,3 @@
+#![no_std]
+extern crate alloc as realalloc;
+pub use realalloc::*;

library/alloc/src/lib.rs

@@ -72,8 +72,6 @@
     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),
@@ -219,28 +217,6 @@
 // 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. Everything that follows should have
-// `#[cfg(not(all(feature = "miri-test", not(any(test, doctest)))))]`. 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]
@@ -250,5 +226,64 @@ extern crate test;
 #[cfg(test)]
 mod testing;
 
-#[cfg(not(all(feature = "miri-test", not(any(test, doctest)))))]
-include!("lib_.rs");
+// 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)
+    }
+}

library/alloc/src/lib_.rs

@@ -0,0 +1,3 @@
+#![no_std]
+extern crate core as realcore;
+pub use realcore::*;