Auto merge of #146931 - RalfJung:miri, r=RalfJung

miri subtree update

Subtree update of `miri` to rust-lang/miri@f6466ce.

Created using https://github.com/rust-lang/josh-sync.

r? `@ghost`

Author: bors

src/tools/miri/.github/workflows/ci.yml

@@ -117,6 +117,41 @@ jobs:
       - name: rustdoc
         run: RUSTDOCFLAGS="-Dwarnings" ./miri doc --document-private-items
 
+  bootstrap:
+    name: bootstrap build
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      # Deliberately skipping `./.github/workflows/setup` as we do our own setup
+      - name: Add cache for cargo
+        id: cache
+        uses: actions/cache@v4
+        with:
+          path: |
+            # Taken from <https://doc.rust-lang.org/nightly/cargo/guide/cargo-home.html#caching-the-cargo-home-in-ci>.
+            # Cache package/registry information
+            ~/.cargo/registry/index
+            ~/.cargo/registry/cache
+            ~/.cargo/git/db
+            # Cache bootstrap downloads
+            ../rust/build/cache
+          key: cargo-bootstrap-${{ hashFiles('rust-version') }}
+          restore-keys: cargo-bootstrap
+      - name: prepare build environment
+        run: |
+          MIRIDIR=$(pwd)
+          cd ..
+          # Bootstrap needs at least depth 2 to function.
+          git clone https://github.com/rust-lang/rust/ rust --depth 2 --revision $(cat "$MIRIDIR/rust-version")
+          cd rust
+          # Replace the in-tree Miri with the current version.
+          rm src/tools/miri -rf
+          ln -s "$MIRIDIR" src/tools/miri
+      - name: check build
+        run: |
+          cd ../rust # ./x does not seem to like being invoked from elsewhere
+          ./x check miri
+
   coverage:
     name: coverage report
     runs-on: ubuntu-latest
@@ -130,7 +165,7 @@ jobs:
   # ALL THE PREVIOUS JOBS NEED TO BE ADDED TO THE `needs` SECTION OF THIS JOB!
   # And they should be added below in `cron-fail-notify` as well.
   conclusion:
-    needs: [test, style, coverage]
+    needs: [test, style, bootstrap, coverage]
     # We need to ensure this job does *not* get skipped if its dependencies fail,
     # because a skipped job is considered a success by GitHub. So we have to
     # overwrite `if:`. We use `!cancelled()` to ensure the job does still not get run
@@ -211,7 +246,7 @@ jobs:
   cron-fail-notify:
     name: cronjob failure notification
     runs-on: ubuntu-latest
-    needs: [test, style, coverage]
+    needs: [test, style, bootstrap, coverage]
     if: ${{ github.event_name == 'schedule' && failure() }}
     steps:
       # Send a Zulip notification

src/tools/miri/miri-script/src/commands.rs

@@ -130,15 +130,15 @@ impl Command {
         let new_commit = sh.read_file("rust-version")?.trim().to_owned();
         let current_commit = {
             let rustc_info = cmd!(sh, "rustc +miri --version -v").read();
-            if rustc_info.is_err() {
-                None
-            } else {
-                let metadata = rustc_version::version_meta_for(&rustc_info.unwrap())?;
+            if let Ok(rustc_info) = rustc_info {
+                let metadata = rustc_version::version_meta_for(&rustc_info)?;
                 Some(
                     metadata
                         .commit_hash
                         .ok_or_else(|| anyhow!("rustc metadata did not contain commit hash"))?,
                 )
+            } else {
+                None
             }
         };
         // Check if we already are at that commit.

src/tools/miri/rust-version

@@ -1 +1 @@
-3f1552a273e43e15f6ed240d00e1efdd6a53e65e
+f6092f224d2b1774b31033f12d0bee626943b02f

src/tools/miri/src/borrow_tracker/tree_borrows/diagnostics.rs

@@ -244,8 +244,8 @@ pub(super) enum TransitionError {
     ChildAccessForbidden(Permission),
     /// A protector was triggered due to an invalid transition that loses
     /// too much permissions.
-    /// For example, if a protected tag goes from `Active` to `Disabled` due
-    /// to a foreign write this will produce a `ProtectedDisabled(Active)`.
+    /// For example, if a protected tag goes from `Unique` to `Disabled` due
+    /// to a foreign write this will produce a `ProtectedDisabled(Unique)`.
     /// This kind of error can only occur on foreign accesses.
     ProtectedDisabled(Permission),
     /// Cannot deallocate because some tag in the allocation is strongly protected.
@@ -504,7 +504,7 @@ impl DisplayFmt {
         if let Some(perm) = perm {
             format!(
                 "{ac}{st}",
-                ac = if perm.is_accessed() { self.accessed.yes } else { self.accessed.no },
+                ac = if perm.accessed() { self.accessed.yes } else { self.accessed.no },
                 st = perm.permission().short_name(),
             )
         } else {

src/tools/miri/src/borrow_tracker/tree_borrows/foreign_access_skipping.rs

@@ -24,7 +24,7 @@ use super::tree::AccessRelatedness;
 /// "manually" reset the parent's SIFA to be at least as strong as the new child's. This is accomplished with the `ensure_no_stronger_than` method.
 ///
 /// Note that we derive Ord and PartialOrd, so the order in which variants are listed below matters:
-/// None < Read < Write. Do not change that order. See the `test_order` test.
+/// None < Read < Write (weaker to stronger). Do not change that order. See the `test_order` test.
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, Default)]
 pub enum IdempotentForeignAccess {
     #[default]

src/tools/miri/src/borrow_tracker/tree_borrows/mod.rs

@@ -294,24 +294,6 @@ trait EvalContextPrivExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
             return interp_ok(Some(Provenance::Concrete { alloc_id, tag: new_tag }));
         }
 
-        let span = this.machine.current_span();
-
-        // When adding a new node, the SIFA of its parents needs to be updated, potentially across
-        // the entire memory range. For the parts that are being accessed below, the access itself
-        // trivially takes care of that. However, we have to do some more work to also deal with the
-        // parts that are not being accessed. Specifically what we do is that we call
-        // `update_last_accessed_after_retag` on the SIFA of the permission set for the part of
-        // memory outside `perm_map` -- so that part is definitely taken care of. The remaining
-        // concern is the part of memory that is in the range of `perms_map`, but not accessed
-        // below. There we have two cases:
-        // * If the type is `!Freeze`, then the non-accessed part uses `nonfreeze_perm`, so the
-        //   `nonfreeze_perm` initialized parts are also fine. We enforce the `freeze_perm` parts to
-        //   be accessed via the assert below, and thus everything is taken care of.
-        // * If the type is `Freeze`, then `freeze_perm` is used everywhere (both inside and outside
-        //   the initial range), and we update everything to have the `freeze_perm`'s SIFA, so there
-        //   are no issues. (And this assert below is not actually needed in this case).
-        assert!(new_perm.freeze_access);
-
         let protected = new_perm.protector.is_some();
         let precise_interior_mut = this
             .machine
@@ -337,7 +319,7 @@ trait EvalContextPrivExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 LocationState::new_non_accessed(perm, sifa)
             }
         };
-        let perms_map = if !precise_interior_mut {
+        let inside_perms = if !precise_interior_mut {
             // For `!Freeze` types, just pretend the entire thing is an `UnsafeCell`.
             let ty_is_freeze = place.layout.ty.is_freeze(*this.tcx, this.typing_env());
             let state = loc_state(ty_is_freeze);
@@ -364,8 +346,8 @@ trait EvalContextPrivExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         let alloc_extra = this.get_alloc_extra(alloc_id)?;
         let mut tree_borrows = alloc_extra.borrow_tracker_tb().borrow_mut();
 
-        for (perm_range, perm) in perms_map.iter_all() {
-            if perm.is_accessed() {
+        for (perm_range, perm) in inside_perms.iter_all() {
+            if perm.accessed() {
                 // Some reborrows incur a read access to the parent.
                 // Adjust range to be relative to allocation start (rather than to `place`).
                 let range_in_alloc = AllocRange {
@@ -401,10 +383,10 @@ trait EvalContextPrivExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
             base_offset,
             orig_tag,
             new_tag,
-            perms_map,
+            inside_perms,
             new_perm.outside_perm,
             protected,
-            span,
+            this.machine.current_span(),
         )?;
         drop(tree_borrows);