Auto merge of #113151 - RalfJung:miri, r=RalfJung,oli-obk

update Miri

r? `@ghost`

.github/workflows/ci.yml

@@ -156,13 +156,13 @@ jobs:
       - name: mark the job as a failure
         run: exit 1
 
-  # Send a Zulip notification when a cron job fails
   cron-fail-notify:
     name: cronjob failure notification
     runs-on: ubuntu-latest
     needs: [build, style]
     if: github.event_name == 'schedule' && (failure() || cancelled())
     steps:
+      # Send a Zulip notification
       - name: Install zulip-send
         run: pip3 install zulip
       - name: Send Zulip notification
@@ -185,3 +185,27 @@ jobs:
           Sincerely,
           The Miri Cronjobs Bot' \
             --user $ZULIP_BOT_EMAIL --api-key $ZULIP_API_TOKEN --site https://rust-lang.zulipchat.com
+      # Attempt to auto-sync with rustc
+      - name: install josh-proxy
+        run: cargo +stable install josh-proxy --git https://github.com/josh-project/josh --tag r22.12.06
+      - name: start josh-proxy
+        run: josh-proxy --local=$HOME/.cache/josh --remote=https://github.com --no-background &
+      - name: setup bot git name and email
+        run: |
+          git config --global user.name 'The Miri Conjob Bot'
+          git config --global user.email 'miri@cron.bot'
+      - name: get changes from rustc
+        run: ./miri rustc-pull
+      - name: format changes (if any)
+        run: |
+          ./miri toolchain
+          ./miri fmt --check || (./miri fmt && git commit -am "fmt")
+      - name: Push changes to a branch
+        run: |
+          git switch -c "rustup$(date -u +%Y-%m)"
+          git push
+      - name: Create Pull Request
+        run: gh pr create -B master --title 'Automatic sync from rustc' --body ''
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+

Cargo.toml

@@ -24,10 +24,6 @@ log = "0.4"
 rand = "0.8"
 smallvec = "1.7"
 
-# A noop dependency that changes in the Rust repository, it's a bit of a hack.
-# See the `src/tools/rustc-workspace-hack/README.md` file in `rust-lang/rust`
-# for more information.
-rustc-workspace-hack = "1.0.0"
 measureme = "10.0.0"
 ctrlc = "3.2.5"
 
@@ -40,7 +36,7 @@ libloading = "0.7"
 
 [dev-dependencies]
 colored = "2"
-ui_test = "0.10"
+ui_test = "0.11.6"
 rustc_version = "0.4"
 # Features chosen to match those required by env_logger, to avoid rebuilds
 regex = { version = "1.5.5", default-features = false, features = ["perf", "std"] }

README.md

@@ -435,6 +435,9 @@ to Miri failing to detect cases of undefined behavior in a program.
   so with this flag.
 * `-Zmiri-force-page-size=<num>` overrides the default page size for an architecture, in multiples of 1k.
   `4` is default for most targets. This value should always be a power of 2 and nonzero.
+* `-Zmiri-unique-is-unique` performs additional aliasing checks for `core::ptr::Unique` to ensure
+  that it could theoretically be considered `noalias`. This flag is experimental and has
+  an effect only when used with `-Zmiri-tree-borrows`.
 
 [function ABI]: https://doc.rust-lang.org/reference/items/functions.html#extern-function-qualifier
 
@@ -575,6 +578,7 @@ Definite bugs found:
 * [`crossbeam-epoch` calling `assume_init` on a partly-initialized `MaybeUninit`](https://github.com/crossbeam-rs/crossbeam/pull/779)
 * [`integer-encoding` dereferencing a misaligned pointer](https://github.com/dermesser/integer-encoding-rs/pull/23)
 * [`rkyv` constructing a `Box<[u8]>` from an overaligned allocation](https://github.com/rkyv/rkyv/commit/a9417193a34757e12e24263178be8b2eebb72456)
+* [Data race in `arc-swap`](https://github.com/vorner/arc-swap/issues/76)
 * [Data race in `thread::scope`](https://github.com/rust-lang/rust/issues/98498)
 * [`regex` incorrectly handling unaligned `Vec<u8>` buffers](https://www.reddit.com/r/rust/comments/vq3mmu/comment/ienc7t0?context=3)
 * [Incorrect use of `compare_exchange_weak` in `once_cell`](https://github.com/matklad/once_cell/issues/186)

cargo-miri/Cargo.toml

@@ -20,11 +20,6 @@ serde_json = "1.0.40"
 cargo_metadata = "0.15.0"
 rustc-build-sysroot = "0.4.1"
 
-# A noop dependency that changes in the Rust repository, it's a bit of a hack.
-# See the `src/tools/rustc-workspace-hack/README.md` file in `rust-lang/rust`
-# for more information.
-rustc-workspace-hack = "1.0.0"
-
 # Enable some feature flags that dev-dependencies need but dependencies
 # do not.  This makes `./miri install` after `./miri build` faster.
 serde = { version = "*", features = ["derive"] }

rust-version

@@ -1 +1 @@
-33c3d101280c8eb3cd8af421bfb56a8afcc3881d
+75726cae37317c7262b69d3e9fd11a3496a88d04

src/bin/miri.rs

@@ -31,9 +31,9 @@ use rustc_middle::{
     query::{ExternProviders, LocalCrate},
     ty::TyCtxt,
 };
-use rustc_session::{EarlyErrorHandler, CtfeBacktrace};
-use rustc_session::config::{OptLevel, CrateType, ErrorOutputType};
+use rustc_session::config::{CrateType, ErrorOutputType, OptLevel};
 use rustc_session::search_paths::PathKind;
+use rustc_session::{CtfeBacktrace, EarlyErrorHandler};
 
 use miri::{BacktraceStyle, BorrowTrackerMethod, ProvenanceMode, RetagFields};
 
@@ -343,6 +343,8 @@ fn main() {
             miri_config.borrow_tracker = None;
         } else if arg == "-Zmiri-tree-borrows" {
             miri_config.borrow_tracker = Some(BorrowTrackerMethod::TreeBorrows);
+        } else if arg == "-Zmiri-unique-is-unique" {
+            miri_config.unique_is_unique = true;
         } else if arg == "-Zmiri-disable-data-race-detector" {
             miri_config.data_race_detector = false;
             miri_config.weak_memory_emulation = false;
@@ -560,6 +562,14 @@ fn main() {
             rustc_args.push(arg);
         }
     }
+    // `-Zmiri-unique-is-unique` should only be used with `-Zmiri-tree-borrows`
+    if miri_config.unique_is_unique
+        && !matches!(miri_config.borrow_tracker, Some(BorrowTrackerMethod::TreeBorrows))
+    {
+        show_error!(
+            "-Zmiri-unique-is-unique only has an effect when -Zmiri-tree-borrows is also used"
+        );
+    }
 
     debug!("rustc arguments: {:?}", rustc_args);
     debug!("crate arguments: {:?}", miri_config.args);

src/borrow_tracker/mod.rs

@@ -103,6 +103,8 @@ pub struct GlobalStateInner {
     pub tracked_call_ids: FxHashSet<CallId>,
     /// Whether to recurse into datatypes when searching for pointers to retag.
     pub retag_fields: RetagFields,
+    /// Whether `core::ptr::Unique` gets special (`Box`-like) handling.
+    pub unique_is_unique: bool,
 }
 
 impl VisitTags for GlobalStateInner {
@@ -170,6 +172,7 @@ impl GlobalStateInner {
         tracked_pointer_tags: FxHashSet<BorTag>,
         tracked_call_ids: FxHashSet<CallId>,
         retag_fields: RetagFields,
+        unique_is_unique: bool,
     ) -> Self {
         GlobalStateInner {
             borrow_tracker_method,
@@ -180,6 +183,7 @@ impl GlobalStateInner {
             tracked_pointer_tags,
             tracked_call_ids,
             retag_fields,
+            unique_is_unique,
         }
     }
 
@@ -244,6 +248,7 @@ impl BorrowTrackerMethod {
             config.tracked_pointer_tags.clone(),
             config.tracked_call_ids.clone(),
             config.retag_fields,
+            config.unique_is_unique,
         ))
     }
 }

src/borrow_tracker/tree_borrows/diagnostics.rs

@@ -12,16 +12,46 @@ use crate::borrow_tracker::tree_borrows::{
 use crate::borrow_tracker::{AccessKind, ProtectorKind};
 use crate::*;
 
+/// Cause of an access: either a real access or one
+/// inserted by Tree Borrows due to a reborrow or a deallocation.
+#[derive(Clone, Copy, Debug)]
+pub enum AccessCause {
+    Explicit(AccessKind),
+    Reborrow,
+    Dealloc,
+}
+
+impl fmt::Display for AccessCause {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::Explicit(kind) => write!(f, "{kind}"),
+            Self::Reborrow => write!(f, "reborrow"),
+            Self::Dealloc => write!(f, "deallocation"),
+        }
+    }
+}
+
+impl AccessCause {
+    fn print_as_access(self, is_foreign: bool) -> String {
+        let rel = if is_foreign { "foreign" } else { "child" };
+        match self {
+            Self::Explicit(kind) => format!("{rel} {kind}"),
+            Self::Reborrow => format!("reborrow (acting as a {rel} read access)"),
+            Self::Dealloc => format!("deallocation (acting as a {rel} write access)"),
+        }
+    }
+}
+
 /// Complete data for an event:
 #[derive(Clone, Debug)]
 pub struct Event {
-    /// Transformation of permissions that occured because of this event
+    /// Transformation of permissions that occured because of this event.
     pub transition: PermTransition,
-    /// Kind of the access that triggered this event
-    pub access_kind: AccessKind,
-    /// Relative position of the tag to the one used for the access
+    /// Kind of the access that triggered this event.
+    pub access_cause: AccessCause,
+    /// Relative position of the tag to the one used for the access.
     pub is_foreign: bool,
-    /// User-visible range of the access
+    /// User-visible range of the access.
     pub access_range: AllocRange,
     /// The transition recorded by this event only occured on a subrange of
     /// `access_range`: a single access on `access_range` triggers several events,
@@ -36,7 +66,7 @@ pub struct Event {
     /// the `TbError`, which should satisfy
     /// `event.transition_range.contains(error.error_offset)`.
     pub transition_range: Range<u64>,
-    /// Line of code that triggered this event
+    /// Line of code that triggered this event.
     pub span: Span,
 }
 
@@ -83,17 +113,19 @@ impl HistoryData {
         self.events.push((Some(created.0.data()), msg_creation));
         for &Event {
             transition,
-            access_kind,
             is_foreign,
+            access_cause,
             access_range,
             span,
             transition_range: _,
         } in &events
         {
             // NOTE: `transition_range` is explicitly absent from the error message, it has no significance
             // to the user. The meaningful one is `access_range`.
-            self.events.push((Some(span.data()), format!("{this} later transitioned to {endpoint} due to a {rel} {access_kind} at offsets {access_range:?}", endpoint = transition.endpoint(), rel = if is_foreign { "foreign" } else { "child" })));
-            self.events.push((None, format!("this corresponds to {}", transition.summary())));
+            let access = access_cause.print_as_access(is_foreign);
+            self.events.push((Some(span.data()), format!("{this} later transitioned to {endpoint} due to a {access} at offsets {access_range:?}", endpoint = transition.endpoint())));
+            self.events
+                .push((None, format!("this transition corresponds to {}", transition.summary())));
         }
     }
 }
@@ -238,9 +270,8 @@ pub(super) struct TbError<'node> {
     /// On accesses rejected due to insufficient permissions, this is the
     /// tag that lacked those permissions.
     pub conflicting_info: &'node NodeDebugInfo,
-    /// Whether this was a Read or Write access. This field is ignored
-    /// when the error was triggered by a deallocation.
-    pub access_kind: AccessKind,
+    // What kind of access caused this error (read, write, reborrow, deallocation)
+    pub access_cause: AccessCause,
     /// Which tag the access that caused this error was made through, i.e.
     /// which tag was used to read/write/deallocate.
     pub accessed_info: &'node NodeDebugInfo,
@@ -250,46 +281,46 @@ impl TbError<'_> {
     /// Produce a UB error.
     pub fn build<'tcx>(self) -> InterpError<'tcx> {
         use TransitionError::*;
-        let kind = self.access_kind;
+        let cause = self.access_cause;
         let accessed = self.accessed_info;
         let conflicting = self.conflicting_info;
         let accessed_is_conflicting = accessed.tag == conflicting.tag;
+        let title = format!("{cause} through {accessed} is forbidden");
         let (title, details, conflicting_tag_name) = match self.error_kind {
             ChildAccessForbidden(perm) => {
                 let conflicting_tag_name =
                     if accessed_is_conflicting { "accessed" } else { "conflicting" };
-                let title = format!("{kind} through {accessed} is forbidden");
                 let mut details = Vec::new();
                 if !accessed_is_conflicting {
                     details.push(format!(
                         "the accessed tag {accessed} is a child of the conflicting tag {conflicting}"
                     ));
                 }
+                let access = cause.print_as_access(/* is_foreign */ false);
                 details.push(format!(
-                    "the {conflicting_tag_name} tag {conflicting} has state {perm} which forbids child {kind}es"
+                    "the {conflicting_tag_name} tag {conflicting} has state {perm} which forbids this {access}"
                 ));
                 (title, details, conflicting_tag_name)
             }
             ProtectedTransition(transition) => {
                 let conflicting_tag_name = "protected";
-                let title = format!("{kind} through {accessed} is forbidden");
+                let access = cause.print_as_access(/* is_foreign */ true);
                 let details = vec![
                     format!(
                         "the accessed tag {accessed} is foreign to the {conflicting_tag_name} tag {conflicting} (i.e., it is not a child)"
                     ),
                     format!(
-                        "the access would cause the {conflicting_tag_name} tag {conflicting} to transition {transition}"
+                        "this {access} would cause the {conflicting_tag_name} tag {conflicting} to transition {transition}"
                     ),
                     format!(
-                        "this is {loss}, which is not allowed for protected tags",
+                        "this transition would be {loss}, which is not allowed for protected tags",
                         loss = transition.summary(),
                     ),
                 ];
                 (title, details, conflicting_tag_name)
             }
             ProtectedDealloc => {
                 let conflicting_tag_name = "strongly protected";
-                let title = format!("deallocation through {accessed} is forbidden");
                 let details = vec![
                     format!(
                         "the allocation of the accessed tag {accessed} also contains the {conflicting_tag_name} tag {conflicting}"