Auto merge of #111036 - RalfJung:miri, r=RalfJung

update Miri

r? `@ghost`

Cargo.lock

@@ -5100,11 +5100,12 @@ checksum = "9e79c4d996edb816c91e4308506774452e55e95c3c9de07b6729e17e15a5ef81"
 
 [[package]]
 name = "ui_test"
-version = "0.5.0"
+version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "54ddb6f31025943e2f9d59237f433711c461a43d9415974c3eb3a4902edc1c1f"
+checksum = "3e10f5f88ce8c331a388deda1e6e2bd533c73ca89cc5f539a3df02ed35c8efba"
 dependencies = [
  "bstr 1.3.0",
+ "cargo-platform",
  "cargo_metadata 0.15.3",
  "color-eyre",
  "colored",
@@ -5113,6 +5114,7 @@ dependencies = [
  "lazy_static",
  "regex",
  "rustc_version",
+ "rustfix",
  "serde",
  "serde_json",
  "tempfile",

src/tools/miri/Cargo.lock

@@ -26,6 +26,12 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "anyhow"
+version = "1.0.70"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7de8ce5e0f9f8d88245311066a578d72b7af3e7088f32783804676302df237e4"
+
 [[package]]
 name = "atty"
 version = "0.2.14"
@@ -292,9 +298,9 @@ dependencies = [
 
 [[package]]
 name = "libffi-sys"
-version = "2.2.1"
+version = "2.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dc65067b78c0fc069771e8b9a9e02df71e08858bec92c1f101377c67b9dca7c7"
+checksum = "f36115160c57e8529781b4183c2bb51fdc1f6d6d1ed345591d84be7703befb3c"
 dependencies = [
  "cc",
 ]
@@ -570,6 +576,18 @@ dependencies = [
  "semver",
 ]
 
+[[package]]
+name = "rustfix"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ecd2853d9e26988467753bd9912c3a126f642d05d229a4b53f5752ee36c56481"
+dependencies = [
+ "anyhow",
+ "log",
+ "serde",
+ "serde_json",
+]
+
 [[package]]
 name = "ryu"
 version = "1.0.12"
@@ -744,11 +762,12 @@ dependencies = [
 
 [[package]]
 name = "ui_test"
-version = "0.5.0"
+version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "54ddb6f31025943e2f9d59237f433711c461a43d9415974c3eb3a4902edc1c1f"
+checksum = "3e10f5f88ce8c331a388deda1e6e2bd533c73ca89cc5f539a3df02ed35c8efba"
 dependencies = [
  "bstr",
+ "cargo-platform",
  "cargo_metadata",
  "color-eyre",
  "colored",
@@ -757,6 +776,7 @@ dependencies = [
  "lazy_static",
  "regex",
  "rustc_version",
+ "rustfix",
  "serde",
  "serde_json",
  "tempfile",

src/tools/miri/Cargo.toml

@@ -39,7 +39,7 @@ libloading = "0.7"
 
 [dev-dependencies]
 colored = "2"
-ui_test = "0.5"
+ui_test = "0.6.2"
 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"] }

src/tools/miri/README.md

@@ -407,7 +407,7 @@ to Miri failing to detect cases of undefined behavior in a program.
 * `-Zmiri-retag-fields=<all|none|scalar>` controls when Stacked Borrows retagging recurses into
   fields. `all` means it always recurses (like `-Zmiri-retag-fields`), `none` means it never
   recurses, `scalar` (the default) means it only recurses for types where we would also emit
-  `noalias` annotations in the generated LLVM IR (types passed as indivudal scalars or pairs of
+  `noalias` annotations in the generated LLVM IR (types passed as individual scalars or pairs of
   scalars). Setting this to `none` is **unsound**.
 * `-Zmiri-tag-gc=<blocks>` configures how often the pointer tag garbage collector runs. The default
   is to search for and remove unreachable tags once every `10000` basic blocks. Setting this to

src/tools/miri/cargo-miri/src/main.rs

@@ -81,7 +81,7 @@ fn main() {
         "miri" => phase_cargo_miri(args),
         "runner" => phase_runner(args, RunnerPhase::Cargo),
         arg if arg == env::var("RUSTC").unwrap() => {
-            // If the first arg is equal to the RUSTC env ariable (which should be set at this
+            // If the first arg is equal to the RUSTC env variable (which should be set at this
             // point), then we need to behave as rustc. This is the somewhat counter-intuitive
             // behavior of having both RUSTC and RUSTC_WRAPPER set
             // (see https://github.com/rust-lang/cargo/issues/10886).

src/tools/miri/miri

@@ -121,10 +121,10 @@ rustc-pull)
     # Update rust-version file. As a separate commit, since making it part of
     # the merge has confused the heck out of josh in the past.
     echo "$FETCH_COMMIT" > rust-version
-    git commit rust-version -m "Preparing for merge from rustc"
+    git commit rust-version -m "Preparing for merge from rustc" || (echo "FAILED to commit rust-version file, something went wrong"; exit 1)
     # Fetch given rustc commit and note down which one that was
-    git fetch http://localhost:8000/rust-lang/rust.git@$FETCH_COMMIT$JOSH_FILTER.git
-    git merge FETCH_HEAD --no-ff -m "Merge from rustc"
+    git fetch http://localhost:8000/rust-lang/rust.git@$FETCH_COMMIT$JOSH_FILTER.git || (echo "FAILED to fetch new commits, something went wrong"; exit 1)
+    git merge FETCH_HEAD --no-ff -m "Merge from rustc" || (echo "FAILED to merge new commits, something went wrong"; exit 1)
     exit 0
     ;;
 rustc-push)

src/tools/miri/rust-version

@@ -1 +1 @@
-d4be8efc6296bace5b1e165f1b34d3c6da76aa8e
+eb62877597000ccf8bb99ab131b5977344afdfa3

src/tools/miri/src/bin/miri.rs

@@ -120,7 +120,7 @@ impl rustc_driver::Callbacks for MiriBeRustCompilerCalls {
     #[allow(rustc::potential_query_instability)] // rustc_codegen_ssa (where this code is copied from) also allows this lint
     fn config(&mut self, config: &mut Config) {
         if config.opts.prints.is_empty() && self.target_crate {
-            // Queries overriden here affect the data stored in `rmeta` files of dependencies,
+            // Queries overridden here affect the data stored in `rmeta` files of dependencies,
             // which will be used later in non-`MIRI_BE_RUSTC` mode.
             config.override_queries = Some(|_, local_providers, _| {
                 // `exported_symbols` and `reachable_non_generics` provided by rustc always returns

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

@@ -238,7 +238,7 @@ pub enum BorrowTrackerMethod {
 }
 
 impl BorrowTrackerMethod {
-    pub fn instanciate_global_state(self, config: &MiriConfig) -> GlobalState {
+    pub fn instantiate_global_state(self, config: &MiriConfig) -> GlobalState {
         RefCell::new(GlobalStateInner::new(
             self,
             config.tracked_pointer_tags.clone(),

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

@@ -292,7 +292,7 @@ impl<'history, 'ecx, 'mir, 'tcx> DiagnosticCx<'history, 'ecx, 'mir, 'tcx> {
             .rev()
             .find_map(|event| {
                 // First, look for a Creation event where the tag and the offset matches. This
-                // ensrues that we pick the right Creation event when a retag isn't uniform due to
+                // ensures that we pick the right Creation event when a retag isn't uniform due to
                 // Freeze.
                 let range = event.retag.range;
                 if event.retag.new_tag == tag

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

@@ -433,7 +433,7 @@ impl<'tcx> Stack {
             let (Some(granting_idx), ProvenanceExtra::Concrete(_)) = (granting_idx, derived_from) else {
                 // The parent is a wildcard pointer or matched the unknown bottom.
                 // This is approximate. Nobody knows what happened, so forget everything.
-                // The new thing is SRW anyway, so we cannot push it "on top of the unkown part"
+                // The new thing is SRW anyway, so we cannot push it "on top of the unknown part"
                 // (for all we know, it might join an SRW group inside the unknown).
                 trace!("reborrow: forgetting stack entirely due to SharedReadWrite reborrow from wildcard or unknown");
                 self.set_unknown_bottom(global.next_ptr_tag);
@@ -825,7 +825,7 @@ trait EvalContextPrivExt<'mir: 'ecx, 'tcx: 'mir, 'ecx>: crate::MiriInterpCxExt<'
         Ok(Some(alloc_id))
     }
 
-    /// Retags an indidual pointer, returning the retagged version.
+    /// Retags an individual pointer, returning the retagged version.
     /// `kind` indicates what kind of reference is being created.
     fn sb_retag_reference(
         &mut self,

src/tools/miri/src/borrow_tracker/stacked_borrows/stack.rs

@@ -51,7 +51,7 @@ impl Stack {
         // Note that the algorithm below is based on considering the tag at read_idx - 1,
         // so precisely considering the tag at index 0 for removal when we have an unknown
         // bottom would complicate the implementation. The simplification of not considering
-        // it does not have a significant impact on the degree to which the GC mititages
+        // it does not have a significant impact on the degree to which the GC mitigates
         // memory growth.
         let mut read_idx = 1;
         let mut write_idx = read_idx;

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

@@ -1,14 +1,90 @@
-use rustc_data_structures::fx::FxHashMap;
-
 use std::fmt;
 use std::ops::Range;
 
+use rustc_data_structures::fx::FxHashMap;
+use rustc_span::{Span, SpanData};
+use rustc_target::abi::Size;
+
 use crate::borrow_tracker::tree_borrows::{
-    err_tb_ub, perms::Permission, tree::LocationState, unimap::UniIndex,
+    perms::{PermTransition, Permission},
+    tree::LocationState,
+    unimap::UniIndex,
 };
 use crate::borrow_tracker::{AccessKind, ProtectorKind};
 use crate::*;
 
+/// Complete data for an event:
+/// - `kind` is what happened to the permissions
+/// - `access_kind` and `access_range` describe the access that caused the event
+/// - `offset` allows filtering only the relevant events for a given memory location
+/// (see how we perform the filtering in `History::extract_relevant`.
+/// - `span` is the line of code in question
+#[derive(Clone, Debug)]
+pub struct Event {
+    pub transition: PermTransition,
+    pub access_kind: AccessKind,
+    pub is_foreign: bool,
+    pub access_range: AllocRange,
+    pub offset: Size,
+    pub span: Span,
+}
+
+/// List of all events that affected a tag.
+/// NOTE: not all of these events are relevant for a particular location,
+/// the events should be filtered before the generation of diagnostics.
+/// Available filtering methods include `History::forget` and `History::extract_relevant`.
+#[derive(Clone, Debug)]
+pub struct History {
+    pub tag: BorTag,
+    pub created: (Span, Permission),
+    pub events: Vec<Event>,
+}
+
+/// History formatted for use by `src/diagnostics.rs`.
+///
+/// NOTE: needs to be `Send` because of a bound on `MachineStopType`, hence
+/// the use of `SpanData` rather than `Span`.
+#[derive(Debug, Clone, Default)]
+pub struct HistoryData {
+    pub events: Vec<(Option<SpanData>, String)>, // includes creation
+}
+
+impl History {
+    /// Record an additional event to the history.
+    pub fn push(&mut self, event: Event) {
+        self.events.push(event);
+    }
+}
+
+impl HistoryData {
+    // Format events from `new_history` into those recorded by `self`.
+    //
+    // NOTE: also converts `Span` to `SpanData`.
+    pub fn extend(
+        &mut self,
+        new_history: History,
+        tag_name: &'static str,
+        show_initial_state: bool,
+    ) {
+        let History { tag, created, events } = new_history;
+        let this = format!("the {tag_name} tag {tag:?}");
+        let msg_initial_state = format!(", in the initial state {}", created.1);
+        let msg_creation = format!(
+            "{this} was created here{maybe_msg_initial_state}",
+            maybe_msg_initial_state = if show_initial_state { &msg_initial_state } else { "" },
+        );
+
+        self.events.push((Some(created.0.data()), msg_creation));
+        for &Event { transition, access_kind, is_foreign, access_range, span, offset: _ } in &events
+        {
+            // NOTE: `offset` 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} then transitioned {transition} due to a {rel} {access_kind} at offsets {access_range:?}", rel = if is_foreign { "foreign" } else { "child" })));
+            self.events.push((None, format!("this corresponds to {}", transition.summary())));
+        }
+    }
+}
+
 /// Some information that is irrelevant for the algorithm but very
 /// convenient to know about a tag for debugging and testing.
 #[derive(Clone, Debug)]
@@ -20,18 +96,29 @@ pub struct NodeDebugInfo {
     /// pointer in the source code.
     /// Helps match tag numbers to human-readable names.
     pub name: Option<String>,
+    /// Notable events in the history of this tag, used for
+    /// diagnostics.
+    ///
+    /// NOTE: by virtue of being part of `NodeDebugInfo`,
+    /// the history is automatically cleaned up by the GC.
+    /// NOTE: this is `!Send`, it needs to be converted before displaying
+    /// the actual diagnostics because `src/diagnostics.rs` requires `Send`.
+    pub history: History,
 }
+
 impl NodeDebugInfo {
-    /// New node info with a name.
-    pub fn new(tag: BorTag) -> Self {
-        Self { tag, name: None }
+    /// Information for a new node. By default it has no
+    /// name and an empty history.
+    pub fn new(tag: BorTag, initial: Permission, span: Span) -> Self {
+        let history = History { tag, created: (span, initial), events: Vec::new() };
+        Self { tag, name: None, history }
     }
 
     /// Add a name to the tag. If a same tag is associated to several pointers,
     /// it can have several names which will be separated by commas.
-    fn add_name(&mut self, name: &str) {
+    pub fn add_name(&mut self, name: &str) {
         if let Some(ref mut prev_name) = &mut self.name {
-            prev_name.push(',');
+            prev_name.push_str(", ");
             prev_name.push_str(name);
         } else {
             self.name = Some(String::from(name));
@@ -42,7 +129,7 @@ impl NodeDebugInfo {
 impl fmt::Display for NodeDebugInfo {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         if let Some(ref name) = self.name {
-            write!(f, "{tag:?} (also named '{name}')", tag = self.tag)
+            write!(f, "{tag:?} ({name})", tag = self.tag)
         } else {
             write!(f, "{tag:?}", tag = self.tag)
         }
@@ -86,7 +173,7 @@ impl<'tcx> Tree {
     }
 }
 
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone, Copy, PartialEq)]
 pub(super) enum TransitionError {
     /// This access is not allowed because some parent tag has insufficient permissions.
     /// For example, if a tag is `Frozen` and encounters a child write this will
@@ -96,63 +183,145 @@ pub(super) enum TransitionError {
     /// A protector was triggered due to an invalid transition that loses
     /// too much permissions.
     /// For example, if a protected tag goes from `Active` to `Frozen` due
-    /// to a foreign write this will produce a `ProtectedTransition(Active, Frozen)`.
+    /// to a foreign write this will produce a `ProtectedTransition(PermTransition(Active, Frozen))`.
     /// This kind of error can only occur on foreign accesses.
-    ProtectedTransition(Permission, Permission),
+    ProtectedTransition(PermTransition),
     /// Cannot deallocate because some tag in the allocation is strongly protected.
     /// This kind of error can only occur on deallocations.
     ProtectedDealloc,
 }
 
+impl History {
+    /// Keep only the tag and creation
+    fn forget(&self) -> Self {
+        History { events: Vec::new(), created: self.created, tag: self.tag }
+    }
+
+    /// Reconstruct the history relevant to `error_offset` knowing that
+    /// its permission followed `complete_transition`.
+    ///
+    /// Here's how we do this:
+    /// - we know `full := complete_transition` the transition of the permission from
+    /// its initialization to the state just before the error was caused,
+    /// we want to find a chain of events that produces `full`
+    /// - we decompose `full` into `pre o post` where
+    /// `pre` is the best applicable transition from recorded events
+    /// - we select the event that caused `pre` and iterate
+    /// to find the chain of events that produces `full := post`
+    ///
+    /// To find the "best applicable transition" for full:
+    /// - eliminate events that cannot be applied because their offset is too big
+    /// - eliminate events that cannot be applied because their starting point is wrong
+    /// - select the one that happened closest to the range of interest
+    fn extract_relevant(&self, complete_transition: PermTransition, error_offset: Size) -> Self {
+        let mut selected_events: Vec<Event> = Vec::new();
+        let mut full = complete_transition;
+        while !full.is_noop() {
+            let (pre, post) = self
+                .events
+                .iter()
+                .filter(|e| e.offset <= error_offset)
+                .filter_map(|pre_canditate| {
+                    full.apply_start(pre_canditate.transition)
+                        .map(|post_canditate| (pre_canditate, post_canditate))
+                })
+                .max_by_key(|(pre_canditate, _post_candidate)| pre_canditate.offset)
+                .unwrap();
+            // If this occurs we will loop infinitely !
+            // Make sure to only put non-noop transitions in `History`.
+            assert!(!pre.transition.is_noop());
+            full = post;
+            selected_events.push(pre.clone());
+        }
+
+        History { events: selected_events, created: self.created, tag: self.tag }
+    }
+}
+
 /// Failures that can occur during the execution of Tree Borrows procedures.
 pub(super) struct TbError<'node> {
     /// What failure occurred.
     pub error_kind: TransitionError,
+    /// The byte at which the conflict occured.
+    pub error_offset: Size,
     /// The tag on which the error was triggered.
     /// On protector violations, this is the tag that was protected.
     /// On accesses rejected due to insufficient permissions, this is the
     /// tag that lacked those permissions.
-    pub faulty_tag: &'node NodeDebugInfo,
+    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,
     /// Which tag the access that caused this error was made through, i.e.
     /// which tag was used to read/write/deallocate.
-    pub tag_of_access: &'node NodeDebugInfo,
+    pub accessed_info: &'node NodeDebugInfo,
 }
 
 impl TbError<'_> {
     /// Produce a UB error.
-    pub fn build<'tcx>(self) -> InterpErrorInfo<'tcx> {
+    pub fn build<'tcx>(self) -> InterpError<'tcx> {
         use TransitionError::*;
-        err_tb_ub(match self.error_kind {
+        let started_as = self.conflicting_info.history.created.1;
+        let kind = self.access_kind;
+        let accessed = self.accessed_info;
+        let conflicting = self.conflicting_info;
+        let accessed_is_conflicting = accessed.tag == conflicting.tag;
+        let (pre_error, title, details, conflicting_tag_name) = match self.error_kind {
             ChildAccessForbidden(perm) => {
-                format!(
-                    "{kind} through {initial} is forbidden because it is a child of {current} which is {perm}.",
-                    kind=self.access_kind,
-                    initial=self.tag_of_access,
-                    current=self.faulty_tag,
-                    perm=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}"
+                    ));
                 }
-            ProtectedTransition(start, end) => {
+                details.push(format!(
+                    "the {conflicting_tag_name} tag {conflicting} has state {perm} which forbids child {kind}es"
+                ));
+                (perm, title, details, conflicting_tag_name)
+            }
+            ProtectedTransition(transition) => {
+                let conflicting_tag_name = "protected";
+                let title = format!("{kind} through {accessed} is forbidden");
+                let details = vec![
                     format!(
-                    "{kind} through {initial} is forbidden because it is a foreign tag for {current}, which would hence change from {start} to {end}, but {current} is protected",
-                    current=self.faulty_tag,
-                    start=start,
-                    end=end,
-                    kind=self.access_kind,
-                    initial=self.tag_of_access,
-                )
+                        "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}"
+                    ),
+                    format!(
+                        "this is {loss}, which is not allowed for protected tags",
+                        loss = transition.summary(),
+                    ),
+                ];
+                (transition.started(), 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 {initial} also contains {current} which is strongly protected, cannot deallocate",
-                    initial=self.tag_of_access,
-                    current=self.faulty_tag,
-                )
+                        "the allocation of the accessed tag {accessed} also contains the {conflicting_tag_name} tag {conflicting}"
+                    ),
+                    format!("the {conflicting_tag_name} tag {conflicting} disallows deallocations"),
+                ];
+                (started_as, title, details, conflicting_tag_name)
             }
-        }).into()
+        };
+        let pre_transition = PermTransition::from(started_as, pre_error).unwrap();
+        let mut history = HistoryData::default();
+        if !accessed_is_conflicting {
+            history.extend(self.accessed_info.history.forget(), "accessed", false);
+        }
+        history.extend(
+            self.conflicting_info.history.extract_relevant(pre_transition, self.error_offset),
+            conflicting_tag_name,
+            true,
+        );
+        err_machine_stop!(TerminationInfo::TreeBorrowsUb { title, details, history })
     }
 }
 

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

@@ -14,7 +14,7 @@ use rustc_middle::{
 
 use crate::*;
 
-mod diagnostics;
+pub mod diagnostics;
 mod perms;
 mod tree;
 mod unimap;
@@ -23,10 +23,6 @@ pub use tree::Tree;
 
 pub type AllocState = Tree;
 
-pub fn err_tb_ub<'tcx>(msg: String) -> InterpError<'tcx> {
-    err_machine_stop!(TerminationInfo::TreeBorrowsUb { msg })
-}
-
 impl<'tcx> Tree {
     /// Create a new allocation, i.e. a new tree
     pub fn new_allocation(
@@ -37,7 +33,8 @@ impl<'tcx> Tree {
         machine: &MiriMachine<'_, 'tcx>,
     ) -> Self {
         let tag = state.base_ptr_tag(id, machine); // Fresh tag for the root
-        Tree::new(tag, size)
+        let span = machine.current_span();
+        Tree::new(tag, size, span)
     }
 
     /// Check that an access on the entire range is permitted, and update
@@ -64,7 +61,8 @@ impl<'tcx> Tree {
             ProvenanceExtra::Wildcard => return Ok(()),
         };
         let global = machine.borrow_tracker.as_ref().unwrap();
-        self.perform_access(access_kind, tag, range, global)
+        let span = machine.current_span();
+        self.perform_access(access_kind, tag, range, global, span)
     }
 
     /// Check that this pointer has permission to deallocate this range.
@@ -82,7 +80,8 @@ impl<'tcx> Tree {
             ProvenanceExtra::Wildcard => return Ok(()),
         };
         let global = machine.borrow_tracker.as_ref().unwrap();
-        self.dealloc(tag, range, global)
+        let span = machine.current_span();
+        self.dealloc(tag, range, global, span)
     }
 
     pub fn expose_tag(&mut self, _tag: BorTag) {
@@ -265,6 +264,7 @@ trait EvalContextPrivExt<'mir: 'ecx, 'tcx: 'mir, 'ecx>: crate::MiriInterpCxExt<'
                 .insert(new_tag, protect);
         }
 
+        let span = this.machine.current_span();
         let alloc_extra = this.get_alloc_extra(alloc_id)?;
         let range = alloc_range(base_offset, ptr_size);
         let mut tree_borrows = alloc_extra.borrow_tracker_tb().borrow_mut();
@@ -272,18 +272,19 @@ trait EvalContextPrivExt<'mir: 'ecx, 'tcx: 'mir, 'ecx>: crate::MiriInterpCxExt<'
         if new_perm.perform_read_access {
             // Count this reborrow as a read access
             let global = &this.machine.borrow_tracker.as_ref().unwrap();
-            tree_borrows.perform_access(AccessKind::Read, orig_tag, range, global)?;
+            let span = this.machine.current_span();
+            tree_borrows.perform_access(AccessKind::Read, orig_tag, range, global, span)?;
             if let Some(data_race) = alloc_extra.data_race.as_ref() {
                 data_race.read(alloc_id, range, &this.machine)?;
             }
         }
 
         // Record the parent-child pair in the tree.
-        tree_borrows.new_child(orig_tag, new_tag, new_perm.initial_state, range)?;
+        tree_borrows.new_child(orig_tag, new_tag, new_perm.initial_state, range, span)?;
         Ok(Some((alloc_id, new_tag)))
     }
 
-    /// Retags an indidual pointer, returning the retagged version.
+    /// Retags an individual pointer, returning the retagged version.
     fn tb_retag_reference(
         &mut self,
         val: &ImmTy<'tcx, Provenance>,

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

@@ -4,7 +4,7 @@ use std::fmt;
 use crate::borrow_tracker::tree_borrows::tree::AccessRelatedness;
 use crate::borrow_tracker::AccessKind;
 
-/// The activation states of a pointer
+/// The activation states of a pointer.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 enum PermissionPriv {
     /// represents: a local reference that has not yet been written to;
@@ -112,47 +112,14 @@ mod transition {
     }
 }
 
-impl PermissionPriv {
-    /// Determines whether a transition that occured is compatible with the presence
-    /// of a Protector. This is not included in the `transition` functions because
-    /// it would distract from the few places where the transition is modified
-    /// because of a protector, but not forbidden.
-    fn protector_allows_transition(self, new: Self) -> bool {
-        match (self, new) {
-            _ if self == new => true,
-            // It is always a protector violation to not be readable anymore
-            (_, Disabled) => false,
-            // In the case of a `Reserved` under a protector, both transitions
-            // `Reserved => Active` and `Reserved => Frozen` can legitimately occur.
-            // The first is standard (Child Write), the second is for Foreign Writes
-            // on protected Reserved where we must ensure that the pointer is not
-            // written to in the future.
-            (Reserved { .. }, Active) | (Reserved { .. }, Frozen) => true,
-            // This pointer should have stayed writeable for the whole function
-            (Active, Frozen) => false,
-            _ => unreachable!("Transition from {self:?} to {new:?} should never be possible"),
-        }
-    }
-}
-
 /// Public interface to the state machine that controls read-write permissions.
+/// This is the "private `enum`" pattern.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct Permission(PermissionPriv);
 
-impl fmt::Display for Permission {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(
-            f,
-            "{}",
-            match self.0 {
-                PermissionPriv::Reserved { .. } => "Reserved",
-                PermissionPriv::Active => "Active",
-                PermissionPriv::Frozen => "Frozen",
-                PermissionPriv::Disabled => "Disabled",
-            }
-        )
-    }
-}
+/// Transition from one permission to the next.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct PermTransition(PermissionPriv, PermissionPriv);
 
 impl Permission {
     /// Default initial permission of the root of a new tree.
@@ -170,8 +137,116 @@ impl Permission {
         Self(Frozen)
     }
 
-    /// Pretty-printing. Needs to be here and not in diagnostics.rs
-    /// because `Self` is private.
+    /// Apply the transition to the inner PermissionPriv.
+    pub fn perform_access(
+        kind: AccessKind,
+        rel_pos: AccessRelatedness,
+        old_perm: Self,
+        protected: bool,
+    ) -> Option<PermTransition> {
+        let old_state = old_perm.0;
+        transition::perform_access(kind, rel_pos, old_state, protected)
+            .map(|new_state| PermTransition(old_state, new_state))
+    }
+}
+
+impl PermTransition {
+    /// All transitions created through normal means (using `perform_access`)
+    /// should be possible, but the same is not guaranteed by construction of
+    /// transitions inferred by diagnostics. This checks that a transition
+    /// reconstructed by diagnostics is indeed one that could happen.
+    fn is_possible(old: PermissionPriv, new: PermissionPriv) -> bool {
+        old <= new
+    }
+
+    pub fn from(old: Permission, new: Permission) -> Option<Self> {
+        Self::is_possible(old.0, new.0).then_some(Self(old.0, new.0))
+    }
+
+    pub fn is_noop(self) -> bool {
+        self.0 == self.1
+    }
+
+    /// Extract result of a transition (checks that the starting point matches).
+    pub fn applied(self, starting_point: Permission) -> Option<Permission> {
+        (starting_point.0 == self.0).then_some(Permission(self.1))
+    }
+
+    /// Extract starting point of a transition
+    pub fn started(self) -> Permission {
+        Permission(self.0)
+    }
+
+    /// Determines whether a transition that occured is compatible with the presence
+    /// of a Protector. This is not included in the `transition` functions because
+    /// it would distract from the few places where the transition is modified
+    /// because of a protector, but not forbidden.
+    ///
+    /// Note: this is not in charge of checking that there *is* a protector,
+    /// it should be used as
+    /// ```
+    /// let no_protector_error = if is_protected(tag) {
+    ///     transition.is_allowed_by_protector()
+    /// };
+    /// ```
+    pub fn is_allowed_by_protector(&self) -> bool {
+        let &Self(old, new) = self;
+        assert!(Self::is_possible(old, new));
+        match (old, new) {
+            _ if old == new => true,
+            // It is always a protector violation to not be readable anymore
+            (_, Disabled) => false,
+            // In the case of a `Reserved` under a protector, both transitions
+            // `Reserved => Active` and `Reserved => Frozen` can legitimately occur.
+            // The first is standard (Child Write), the second is for Foreign Writes
+            // on protected Reserved where we must ensure that the pointer is not
+            // written to in the future.
+            (Reserved { .. }, Active) | (Reserved { .. }, Frozen) => true,
+            // This pointer should have stayed writeable for the whole function
+            (Active, Frozen) => false,
+            _ => unreachable!("Transition from {old:?} to {new:?} should never be possible"),
+        }
+    }
+
+    /// Composition function: get the transition that can be added after `app` to
+    /// produce `self`.
+    pub fn apply_start(self, app: Self) -> Option<Self> {
+        let new_start = app.applied(Permission(self.0))?;
+        Self::from(new_start, Permission(self.1))
+    }
+}
+
+pub mod diagnostics {
+    use super::*;
+    impl fmt::Display for PermissionPriv {
+        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+            write!(
+                f,
+                "{}",
+                match self {
+                    PermissionPriv::Reserved { .. } => "Reserved",
+                    PermissionPriv::Active => "Active",
+                    PermissionPriv::Frozen => "Frozen",
+                    PermissionPriv::Disabled => "Disabled",
+                }
+            )
+        }
+    }
+
+    impl fmt::Display for PermTransition {
+        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+            write!(f, "from {} to {}", self.0, self.1)
+        }
+    }
+
+    impl fmt::Display for Permission {
+        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+            write!(f, "{}", self.0)
+        }
+    }
+
+    impl Permission {
+        /// Abbreviated name of the permission (uniformly 3 letters for nice alignment).
         pub fn short_name(self) -> &'static str {
             // Make sure there are all of the same length as each other
             // and also as `diagnostics::DisplayFmtPermission.uninit` otherwise
@@ -184,29 +259,26 @@ impl Permission {
                 Disabled => "Dis",
             }
         }
-
-    /// Check that there are no complaints from a possible protector.
-    ///
-    /// Note: this is not in charge of checking that there *is* a protector,
-    /// it should be used as
-    /// ```
-    /// let no_protector_error = if is_protected(tag) {
-    ///     old_perm.protector_allows_transition(new_perm)
-    /// };
-    /// ```
-    pub fn protector_allows_transition(self, new: Self) -> bool {
-        self.0.protector_allows_transition(new.0)
     }
 
-    /// Apply the transition to the inner PermissionPriv.
-    pub fn perform_access(
-        kind: AccessKind,
-        rel_pos: AccessRelatedness,
-        old_perm: Self,
-        protected: bool,
-    ) -> Option<Self> {
-        let old_state = old_perm.0;
-        transition::perform_access(kind, rel_pos, old_state, protected).map(Self)
+    impl PermTransition {
+        /// Readable explanation of the consequences of an event.
+        /// Fits in the sentence "This accessed caused {trans.summary()}".
+        ///
+        /// Important: for the purposes of this explanation, `Reserved` is considered
+        /// to have write permissions, because that's what the diagnostics care about
+        /// (otherwise `Reserved -> Frozen` would be considered a noop).
+        pub fn summary(&self) -> &'static str {
+            assert!(Self::is_possible(self.0, self.1));
+            match (self.0, self.1) {
+                (_, Active) => "an activation",
+                (_, Frozen) => "a loss of write permissions",
+                (Frozen, Disabled) => "a loss of read permissions",
+                (_, Disabled) => "a loss of read and write permissions",
+                (old, new) =>
+                    unreachable!("Transition from {old:?} to {new:?} should never be possible"),
+            }
+        }
     }
 }
 

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

@@ -14,10 +14,11 @@ use smallvec::SmallVec;
 
 use rustc_const_eval::interpret::InterpResult;
 use rustc_data_structures::fx::FxHashSet;
+use rustc_span::Span;
 use rustc_target::abi::Size;
 
 use crate::borrow_tracker::tree_borrows::{
-    diagnostics::{NodeDebugInfo, TbError, TransitionError},
+    diagnostics::{self, NodeDebugInfo, TbError, TransitionError},
     unimap::{UniEntry, UniIndex, UniKeyMap, UniValMap},
     Permission,
 };
@@ -34,7 +35,7 @@ pub(super) struct LocationState {
     /// Before initialization we still apply some preemptive transitions on
     /// `permission` to know what to do in case it ever gets initialized,
     /// but these can never cause any immediate UB. There can however be UB
-    /// the moment we attempt to initalize (i.e. child-access) because some
+    /// the moment we attempt to initialize (i.e. child-access) because some
     /// foreign access done between the creation and the initialization is
     /// incompatible with child accesses.
     initialized: bool,
@@ -118,7 +119,7 @@ pub(super) struct Node {
 /// Data given to the transition function
 struct NodeAppArgs<'node> {
     /// Node on which the transition is currently being applied
-    node: &'node Node,
+    node: &'node mut Node,
     /// Mutable access to its permissions
     perm: UniEntry<'node, LocationState>,
     /// Relative position of the access
@@ -131,14 +132,17 @@ struct ErrHandlerArgs<'node, InErr> {
     /// Tag that triggered the error (not the tag that was accessed,
     /// rather the parent tag that had insufficient permissions or the
     /// non-parent tag that had a protector).
-    faulty_tag: &'node NodeDebugInfo,
+    conflicting_info: &'node NodeDebugInfo,
+    /// Information about the tag that was accessed just before the
+    /// error was triggered.
+    accessed_info: &'node NodeDebugInfo,
 }
 /// Internal contents of `Tree` with the minimum of mutable access for
 /// the purposes of the tree traversal functions: the permissions (`perms`) can be
 /// updated but not the tree structure (`tag_mapping` and `nodes`)
 struct TreeVisitor<'tree> {
     tag_mapping: &'tree UniKeyMap<BorTag>,
-    nodes: &'tree UniValMap<Node>,
+    nodes: &'tree mut UniValMap<Node>,
     perms: &'tree mut UniValMap<LocationState>,
 }
 
@@ -167,6 +171,7 @@ impl<'tree> TreeVisitor<'tree> {
     ) -> Result<(), OutErr>
 where {
         struct TreeVisitAux<NodeApp, ErrHandler> {
+            accessed_tag: UniIndex,
             f_propagate: NodeApp,
             err_builder: ErrHandler,
             stack: Vec<(UniIndex, AccessRelatedness)>,
@@ -190,15 +195,21 @@ where {
                 rel_pos: AccessRelatedness,
             ) -> Result<(), OutErr> {
                 // 1. apply the propagation function
-                let node = this.nodes.get(tag).unwrap();
+                let node = this.nodes.get_mut(tag).unwrap();
                 let recurse =
                     (self.f_propagate)(NodeAppArgs { node, perm: this.perms.entry(tag), rel_pos })
                         .map_err(|error_kind| {
                             (self.err_builder)(ErrHandlerArgs {
                                 error_kind,
-                                faulty_tag: &node.debug_info,
+                                conflicting_info: &this.nodes.get(tag).unwrap().debug_info,
+                                accessed_info: &this
+                                    .nodes
+                                    .get(self.accessed_tag)
+                                    .unwrap()
+                                    .debug_info,
                             })
                         })?;
+                let node = this.nodes.get(tag).unwrap();
                 // 2. add the children to the stack for future traversal
                 if matches!(recurse, ContinueTraversal::Recurse) {
                     let child_rel = rel_pos.for_child();
@@ -214,7 +225,8 @@ where {
         }
 
         let start_idx = self.tag_mapping.get(&start).unwrap();
-        let mut stack = TreeVisitAux { f_propagate, err_builder, stack: Vec::new() };
+        let mut stack =
+            TreeVisitAux { accessed_tag: start_idx, f_propagate, err_builder, stack: Vec::new() };
         {
             let mut path_ascend = Vec::new();
             // First climb to the root while recording the path
@@ -262,12 +274,15 @@ where {
 
 impl Tree {
     /// Create a new tree, with only a root pointer.
-    pub fn new(root_tag: BorTag, size: Size) -> Self {
+    pub fn new(root_tag: BorTag, size: Size, span: Span) -> Self {
         let root_perm = Permission::new_root();
         let mut tag_mapping = UniKeyMap::default();
         let root_idx = tag_mapping.insert(root_tag);
         let nodes = {
             let mut nodes = UniValMap::<Node>::default();
+            let mut debug_info = NodeDebugInfo::new(root_tag, root_perm, span);
+            // name the root so that all allocations contain one named pointer
+            debug_info.add_name("root of the allocation");
             nodes.insert(
                 root_idx,
                 Node {
@@ -275,7 +290,7 @@ impl Tree {
                     parent: None,
                     children: SmallVec::default(),
                     default_initial_perm: root_perm,
-                    debug_info: NodeDebugInfo::new(root_tag),
+                    debug_info,
                 },
             );
             nodes
@@ -297,6 +312,7 @@ impl<'tcx> Tree {
         new_tag: BorTag,
         default_initial_perm: Permission,
         range: AllocRange,
+        span: Span,
     ) -> InterpResult<'tcx> {
         assert!(!self.tag_mapping.contains_key(&new_tag));
         let idx = self.tag_mapping.insert(new_tag);
@@ -309,7 +325,7 @@ impl<'tcx> Tree {
                 parent: Some(parent_idx),
                 children: SmallVec::default(),
                 default_initial_perm,
-                debug_info: NodeDebugInfo::new(new_tag),
+                debug_info: NodeDebugInfo::new(new_tag, default_initial_perm, span),
             },
         );
         // Register new_tag as a child of parent_tag
@@ -330,11 +346,11 @@ impl<'tcx> Tree {
         tag: BorTag,
         range: AllocRange,
         global: &GlobalState,
+        span: Span, // diagnostics
     ) -> InterpResult<'tcx> {
-        self.perform_access(AccessKind::Write, tag, range, global)?;
-        let access_info = &self.nodes.get(self.tag_mapping.get(&tag).unwrap()).unwrap().debug_info;
-        for (_range, perms) in self.rperms.iter_mut(range.start, range.size) {
-            TreeVisitor { nodes: &self.nodes, tag_mapping: &self.tag_mapping, perms }
+        self.perform_access(AccessKind::Write, tag, range, global, span)?;
+        for (offset, perms) in self.rperms.iter_mut(range.start, range.size) {
+            TreeVisitor { nodes: &mut self.nodes, tag_mapping: &self.tag_mapping, perms }
                 .traverse_parents_this_children_others(
                     tag,
                     |args: NodeAppArgs<'_>| -> Result<ContinueTraversal, TransitionError> {
@@ -347,13 +363,14 @@ impl<'tcx> Tree {
                             Ok(ContinueTraversal::Recurse)
                         }
                     },
-                    |args: ErrHandlerArgs<'_, TransitionError>| -> InterpErrorInfo<'tcx> {
-                        let ErrHandlerArgs { error_kind, faulty_tag } = args;
+                    |args: ErrHandlerArgs<'_, TransitionError>| -> InterpError<'tcx> {
+                        let ErrHandlerArgs { error_kind, conflicting_info, accessed_info } = args;
                         TbError {
-                            faulty_tag,
+                            conflicting_info,
                             access_kind: AccessKind::Write,
+                            error_offset: offset,
                             error_kind,
-                            tag_of_access: access_info,
+                            accessed_info,
                         }
                         .build()
                     },
@@ -373,10 +390,10 @@ impl<'tcx> Tree {
         tag: BorTag,
         range: AllocRange,
         global: &GlobalState,
+        span: Span, // diagnostics
     ) -> InterpResult<'tcx> {
-        let access_info = &self.nodes.get(self.tag_mapping.get(&tag).unwrap()).unwrap().debug_info;
-        for (_range, perms) in self.rperms.iter_mut(range.start, range.size) {
-            TreeVisitor { nodes: &self.nodes, tag_mapping: &self.tag_mapping, perms }
+        for (offset, perms) in self.rperms.iter_mut(range.start, range.size) {
+            TreeVisitor { nodes: &mut self.nodes, tag_mapping: &self.tag_mapping, perms }
                 .traverse_parents_this_children_others(
                     tag,
                     |args: NodeAppArgs<'_>| -> Result<ContinueTraversal, TransitionError> {
@@ -424,23 +441,41 @@ impl<'tcx> Tree {
 
                         let old_perm = old_state.permission;
                         let protected = global.borrow().protected_tags.contains_key(&node.tag);
-                        let new_perm =
+                        let transition =
                             Permission::perform_access(access_kind, rel_pos, old_perm, protected)
                                 .ok_or(TransitionError::ChildAccessForbidden(old_perm))?;
                         if protected
                             // Can't trigger Protector on uninitialized locations
                             && old_state.initialized
-                            && !old_perm.protector_allows_transition(new_perm)
+                            && !transition.is_allowed_by_protector()
                         {
-                            return Err(TransitionError::ProtectedTransition(old_perm, new_perm));
+                            return Err(TransitionError::ProtectedTransition(transition));
+                        }
+                        // Record the event as part of the history
+                        if !transition.is_noop() {
+                            node.debug_info.history.push(diagnostics::Event {
+                                transition,
+                                access_kind,
+                                access_range: range,
+                                is_foreign: rel_pos.is_foreign(),
+                                offset,
+                                span,
+                            });
+                            old_state.permission =
+                                transition.applied(old_state.permission).unwrap();
                         }
-                        old_state.permission = new_perm;
                         old_state.initialized |= !rel_pos.is_foreign();
                         Ok(ContinueTraversal::Recurse)
                     },
-                    |args: ErrHandlerArgs<'_, TransitionError>| -> InterpErrorInfo<'tcx> {
-                        let ErrHandlerArgs { error_kind, faulty_tag } = args;
-                        TbError { faulty_tag, access_kind, error_kind, tag_of_access: access_info }
+                    |args: ErrHandlerArgs<'_, TransitionError>| -> InterpError<'tcx> {
+                        let ErrHandlerArgs { error_kind, conflicting_info, accessed_info } = args;
+                        TbError {
+                            conflicting_info,
+                            access_kind,
+                            error_offset: offset,
+                            error_kind,
+                            accessed_info,
+                        }
                         .build()
                     },
                 )?;

src/tools/miri/src/concurrency/data_race.rs

@@ -1199,7 +1199,7 @@ pub struct GlobalState {
 
     /// A flag to mark we are currently performing
     /// a data race free action (such as atomic access)
-    /// to supress the race detector
+    /// to suppress the race detector
     ongoing_action_data_race_free: Cell<bool>,
 
     /// Mapping of a vector index to a known set of thread

src/tools/miri/src/concurrency/init_once.rs

@@ -151,7 +151,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         assert_eq!(
             init_once.status,
             InitOnceStatus::Uninitialized,
-            "begining already begun or complete init once"
+            "beginning already begun or complete init once"
         );
         init_once.status = InitOnceStatus::Begun;
     }

src/tools/miri/src/concurrency/range_object_map.rs

@@ -25,9 +25,9 @@ pub struct RangeObjectMap<T> {
 
 #[derive(Clone, Debug, PartialEq)]
 pub enum AccessType {
-    /// The access perfectly overlaps (same offset and range) with the exsiting allocation
+    /// The access perfectly overlaps (same offset and range) with the existing allocation
     PerfectlyOverlapping(Position),
-    /// The access does not touch any exising allocation
+    /// The access does not touch any existing allocation
     Empty(Position),
     /// The access overlaps with one or more existing allocations
     ImperfectlyOverlapping(Range<Position>),
@@ -115,7 +115,7 @@ impl<T> RangeObjectMap<T> {
     // want to repeat the binary search on each time, so we ask the caller to supply Position
     pub fn insert_at_pos(&mut self, pos: Position, range: AllocRange, data: T) {
         self.v.insert(pos, Elem { range, data });
-        // If we aren't the first element, then our start must be greater than the preivous element's end
+        // If we aren't the first element, then our start must be greater than the previous element's end
         if pos > 0 {
             assert!(self.v[pos - 1].range.end() <= range.start);
         }

src/tools/miri/src/concurrency/sync.rs

@@ -143,7 +143,7 @@ struct Condvar {
     waiters: VecDeque<CondvarWaiter>,
     /// Tracks the happens-before relationship
     /// between a cond-var signal and a cond-var
-    /// wait during a non-suprious signal event.
+    /// wait during a non-spurious signal event.
     /// Contains the clock of the last thread to
     /// perform a futex-signal.
     data_race: VClock,
@@ -373,7 +373,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
                 .expect("invariant violation: lock_count == 0 iff the thread is unlocked");
             if mutex.lock_count == 0 {
                 mutex.owner = None;
-                // The mutex is completely unlocked. Try transfering ownership
+                // The mutex is completely unlocked. Try transferring ownership
                 // to another thread.
                 if let Some(data_race) = &this.machine.data_race {
                     data_race.validate_lock_release(

src/tools/miri/src/concurrency/thread.rs

@@ -272,9 +272,8 @@ impl Time {
     fn get_wait_time(&self, clock: &Clock) -> Duration {
         match self {
             Time::Monotonic(instant) => instant.duration_since(clock.now()),
-            Time::RealTime(time) => {
-                time.duration_since(SystemTime::now()).unwrap_or(Duration::new(0, 0))
-            }
+            Time::RealTime(time) =>
+                time.duration_since(SystemTime::now()).unwrap_or(Duration::new(0, 0)),
         }
     }
 }
@@ -823,7 +822,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         }
 
         // Write the current thread-id, switch to the next thread later
-        // to treat this write operation as occuring on the current thread.
+        // to treat this write operation as occurring on the current thread.
         if let Some(thread_info_place) = thread {
             this.write_scalar(
                 Scalar::from_uint(new_thread_id.to_u32(), thread_info_place.layout.size),
@@ -832,7 +831,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         }
 
         // Finally switch to new thread so that we can push the first stackframe.
-        // After this all accesses will be treated as occuring in the new thread.
+        // After this all accesses will be treated as occurring in the new thread.
         let old_thread_id = this.set_active_thread(new_thread_id);
 
         // Perform the function pointer load in the new thread frame.

src/tools/miri/src/concurrency/vector_clock.rs

@@ -212,16 +212,14 @@ impl PartialOrd for VClock {
         for (l, r) in iter {
             match order {
                 Ordering::Equal => order = l.cmp(r),
-                Ordering::Less => {
+                Ordering::Less =>
                     if l > r {
                         return None;
-                    }
-                }
-                Ordering::Greater => {
+                    },
+                Ordering::Greater =>
                     if l < r {
                         return None;
-                    }
-                }
+                    },
             }
         }
 
@@ -236,13 +234,15 @@ impl PartialOrd for VClock {
             Ordering::Equal => Some(order),
             // Right has at least 1 element > than the implicit 0,
             // so the only valid values are Ordering::Less or None.
-            Ordering::Less => match order {
+            Ordering::Less =>
+                match order {
                     Ordering::Less | Ordering::Equal => Some(Ordering::Less),
                     Ordering::Greater => None,
                 },
             // Left has at least 1 element > than the implicit 0,
             // so the only valid values are Ordering::Greater or None.
-            Ordering::Greater => match order {
+            Ordering::Greater =>
+                match order {
                     Ordering::Greater | Ordering::Equal => Some(Ordering::Greater),
                     Ordering::Less => None,
                 },

src/tools/miri/src/concurrency/weak_memory.rs

@@ -24,7 +24,7 @@
 //! However, this model lacks SC accesses and is therefore unusable by Miri (SC accesses are everywhere in library code).
 //!
 //! If you find anything that proposes a relaxed memory model that is C++20-consistent, supports all orderings Rust's atomic accesses
-//! and fences accept, and is implementable (with operational semanitcs), please open a GitHub issue!
+//! and fences accept, and is implementable (with operational semantics), please open a GitHub issue!
 //!
 //! One characteristic of this implementation, in contrast to some other notable operational models such as ones proposed in
 //! Taming Release-Acquire Consistency by Ori Lahav et al. (<https://plv.mpi-sws.org/sra/paper.pdf>) or Promising Semantics noted above,
@@ -32,8 +32,8 @@
 //! and shared across all threads. This is more memory efficient but does require store elements (representing writes to a location) to record
 //! information about reads, whereas in the other two models it is the other way round: reads points to the write it got its value from.
 //! Additionally, writes in our implementation do not have globally unique timestamps attached. In the other two models this timestamp is
-//! used to make sure a value in a thread's view is not overwritten by a write that occured earlier than the one in the existing view.
-//! In our implementation, this is detected using read information attached to store elements, as there is no data strucutre representing reads.
+//! used to make sure a value in a thread's view is not overwritten by a write that occurred earlier than the one in the existing view.
+//! In our implementation, this is detected using read information attached to store elements, as there is no data structure representing reads.
 //!
 //! The C++ memory model is built around the notion of an 'atomic object', so it would be natural
 //! to attach store buffers to atomic objects. However, Rust follows LLVM in that it only has
@@ -48,7 +48,7 @@
 //! One consequence of this difference is that safe/sound Rust allows for more operations on atomic locations
 //! than the C++20 atomic API was intended to allow, such as non-atomically accessing
 //! a previously atomically accessed location, or accessing previously atomically accessed locations with a differently sized operation
-//! (such as accessing the top 16 bits of an AtomicU32). These senarios are generally undiscussed in formalisations of C++ memory model.
+//! (such as accessing the top 16 bits of an AtomicU32). These scenarios are generally undiscussed in formalisations of C++ memory model.
 //! In Rust, these operations can only be done through a `&mut AtomicFoo` reference or one derived from it, therefore these operations
 //! can only happen after all previous accesses on the same locations. This implementation is adapted to allow these operations.
 //! A mixed atomicity read that races with writes, or a write that races with reads or writes will still cause UBs to be thrown.
@@ -61,7 +61,7 @@
 //
 // 2. In the operational semantics, each store element keeps the timestamp of a thread when it loads from the store.
 // If the same thread loads from the same store element multiple times, then the timestamps at all loads are saved in a list of load elements.
-// This is not necessary as later loads by the same thread will always have greater timetstamp values, so we only need to record the timestamp of the first
+// This is not necessary as later loads by the same thread will always have greater timestamp values, so we only need to record the timestamp of the first
 // load by each thread. This optimisation is done in tsan11
 // (https://github.com/ChrisLidbury/tsan11/blob/ecbd6b81e9b9454e01cba78eb9d88684168132c7/lib/tsan/rtl/tsan_relaxed.h#L35-L37)
 // and here.
@@ -193,7 +193,7 @@ impl StoreBufferAlloc {
                     buffers.remove_pos_range(pos_range);
                 }
                 AccessType::Empty(_) => {
-                    // The range had no weak behaivours attached, do nothing
+                    // The range had no weak behaviours attached, do nothing
                 }
             }
         }
@@ -336,7 +336,7 @@ impl<'mir, 'tcx: 'mir> StoreBuffer {
         let mut found_sc = false;
         // FIXME: we want an inclusive take_while (stops after a false predicate, but
         // includes the element that gave the false), but such function doesn't yet
-        // exist in the standard libary https://github.com/rust-lang/rust/issues/62208
+        // exist in the standard library https://github.com/rust-lang/rust/issues/62208
         // so we have to hack around it with keep_searching
         let mut keep_searching = true;
         let candidates = self

src/tools/miri/src/diagnostics.rs

@@ -7,6 +7,7 @@ use rustc_span::{source_map::DUMMY_SP, SpanData, Symbol};
 use rustc_target::abi::{Align, Size};
 
 use crate::borrow_tracker::stacked_borrows::diagnostics::TagHistory;
+use crate::borrow_tracker::tree_borrows::diagnostics as tree_diagnostics;
 use crate::*;
 
 /// Details of premature program termination.
@@ -23,8 +24,9 @@ pub enum TerminationInfo {
         history: Option<TagHistory>,
     },
     TreeBorrowsUb {
-        msg: String,
-        // FIXME: incomplete
+        title: String,
+        details: Vec<String>,
+        history: tree_diagnostics::HistoryData,
     },
     Int2PtrWithStrictProvenance,
     Deadlock,
@@ -65,7 +67,7 @@ impl fmt::Display for TerminationInfo {
                     "integer-to-pointer casts and `ptr::from_exposed_addr` are not supported with `-Zmiri-strict-provenance`"
                 ),
             StackedBorrowsUb { msg, .. } => write!(f, "{msg}"),
-            TreeBorrowsUb { msg } => write!(f, "{msg}"),
+            TreeBorrowsUb { title, .. } => write!(f, "{title}"),
             Deadlock => write!(f, "the evaluated program deadlocked"),
             MultipleSymbolDefinitions { link_name, .. } =>
                 write!(f, "multiple definitions of symbol `{link_name}`"),
@@ -219,10 +221,16 @@ pub fn report_error<'tcx, 'mir>(
                 }
                 helps
             },
-            TreeBorrowsUb { .. } => {
-                let helps = vec![
-                    (None, format!("this indicates a potential bug in the program: it performed an invalid operation, but the Tree Borrows rules it violated are still experimental")),
+            TreeBorrowsUb { title: _, details, history } => {
+                let mut helps = vec![
+                    (None, format!("this indicates a potential bug in the program: it performed an invalid operation, but the Tree Borrows rules it violated are still experimental"))
                 ];
+                for m in details {
+                    helps.push((None, m.clone()));
+                }
+                for event in history.events.clone() {
+                    helps.push(event);
+                }
                 helps
             }
             MultipleSymbolDefinitions { first, first_crate, second, second_crate, .. } =>

src/tools/miri/src/eval.rs

@@ -376,7 +376,7 @@ pub fn create_ecx<'mir, 'tcx: 'mir>(
 
             // Inlining of `DEFAULT` from
             // https://github.com/rust-lang/rust/blob/master/compiler/rustc_session/src/config/sigpipe.rs.
-            // Alaways using DEFAULT is okay since we don't support signals in Miri anyway.
+            // Always using DEFAULT is okay since we don't support signals in Miri anyway.
             let sigpipe = 2;
 
             ecx.call_function(
@@ -460,7 +460,7 @@ pub fn eval_entry<'tcx>(
             return None;
         }
         // Check for memory leaks.
-        info!("Additonal static roots: {:?}", ecx.machine.static_roots);
+        info!("Additional static roots: {:?}", ecx.machine.static_roots);
         let leaks = ecx.find_leaked_allocations(&ecx.machine.static_roots);
         if !leaks.is_empty() {
             report_leaks(&ecx, leaks);

src/tools/miri/src/helpers.rs

@@ -524,7 +524,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
                 }
             }
 
-            // Make sure we visit aggregrates in increasing offset order.
+            // Make sure we visit aggregates in increasing offset order.
             fn visit_aggregate(
                 &mut self,
                 place: &MPlaceTy<'tcx, Provenance>,

src/tools/miri/src/intptrcast.rs

@@ -77,7 +77,7 @@ impl<'mir, 'tcx> GlobalStateInner {
             Ok(pos) => Some(global_state.int_to_ptr_map[pos].1),
             Err(0) => None,
             Err(pos) => {
-                // This is the largest of the adresses smaller than `int`,
+                // This is the largest of the addresses smaller than `int`,
                 // i.e. the greatest lower bound (glb)
                 let (glb, alloc_id) = global_state.int_to_ptr_map[pos - 1];
                 // This never overflows because `addr >= glb`

src/tools/miri/src/machine.rs

@@ -32,8 +32,14 @@ use crate::{
     *,
 };
 
-/// The number of the available real-time signal with the lowest priority.
-/// Dummy constant related to epoll, must be between 32 and 64.
+/// First real-time signal.
+/// `signal(7)` says this must be between 32 and 64 and specifies 34 or 35
+/// as typical values.
+pub const SIGRTMIN: i32 = 34;
+
+/// Last real-time signal.
+/// `signal(7)` says it must be between 32 and 64 and specifies
+/// `SIGRTMAX` - `SIGRTMIN` >= 8 (which is the value of `_POSIX_RTSIG_MAX`)
 pub const SIGRTMAX: i32 = 42;
 
 /// Extra data stored with each stack frame
@@ -495,9 +501,9 @@ impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {
             measureme::Profiler::new(out).expect("Couldn't create `measureme` profiler")
         });
         let rng = StdRng::seed_from_u64(config.seed.unwrap_or(0));
-        let borrow_tracker = config.borrow_tracker.map(|bt| bt.instanciate_global_state(config));
+        let borrow_tracker = config.borrow_tracker.map(|bt| bt.instantiate_global_state(config));
         let data_race = config.data_race_detector.then(|| data_race::GlobalState::new(config));
-        // Determinine page size, stack address, and stack size.
+        // Determine page size, stack address, and stack size.
         // These values are mostly meaningless, but the stack address is also where we start
         // allocating physical integer addresses for all allocations.
         let page_size = if let Some(page_size) = config.page_size {

src/tools/miri/src/shims/foreign_items.rs

@@ -46,7 +46,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         // This list should be kept in sync with the one from libstd.
         let min_align = match this.tcx.sess.target.arch.as_ref() {
             "x86" | "arm" | "mips" | "powerpc" | "powerpc64" | "asmjs" | "wasm32" => 8,
-            "x86_64" | "aarch64" | "mips64" | "s390x" | "sparc64" => 16,
+            "x86_64" | "aarch64" | "mips64" | "s390x" | "sparc64" | "loongarch64" => 16,
             arch => bug!("unsupported target architecture for malloc: `{}`", arch),
         };
         // Windows always aligns, even small allocations.
@@ -744,6 +744,44 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
                     dest,
                 )?;
             }
+            "memcpy" => {
+                let [ptr_dest, ptr_src, n] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let ptr_dest = this.read_pointer(ptr_dest)?;
+                let ptr_src = this.read_pointer(ptr_src)?;
+                let n = this.read_target_usize(n)?;
+                this.mem_copy(
+                    ptr_src,
+                    Align::ONE,
+                    ptr_dest,
+                    Align::ONE,
+                    Size::from_bytes(n),
+                    true,
+                )?;
+                this.write_pointer(ptr_dest, dest)?;
+            }
+            "strcpy" => {
+                let [ptr_dest, ptr_src] =
+                    this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+                let ptr_dest = this.read_pointer(ptr_dest)?;
+                let ptr_src = this.read_pointer(ptr_src)?;
+
+                // We use `read_c_str` to determine the amount of data to copy,
+                // and then use `mem_copy` for the actual copy. This means
+                // pointer provenance is preserved by this implementation of `strcpy`.
+                // That is probably overly cautious, but there also is no fundamental
+                // reason to have `strcpy` destroy pointer provenance.
+                let n = this.read_c_str(ptr_src)?.len().checked_add(1).unwrap();
+                this.mem_copy(
+                    ptr_src,
+                    Align::ONE,
+                    ptr_dest,
+                    Align::ONE,
+                    Size::from_bytes(n),
+                    true,
+                )?;
+                this.write_pointer(ptr_dest, dest)?;
+            }
 
             // math functions (note that there are also intrinsics for some other functions)
             #[rustfmt::skip]

src/tools/miri/src/shims/intrinsics/simd.rs

@@ -585,9 +585,9 @@ fn simd_element_to_bool(elem: ImmTy<'_, Provenance>) -> InterpResult<'_, bool> {
     })
 }
 
-fn simd_bitmask_index(idx: u32, vec_len: u32, endianess: Endian) -> u32 {
+fn simd_bitmask_index(idx: u32, vec_len: u32, endianness: Endian) -> u32 {
     assert!(idx < vec_len);
-    match endianess {
+    match endianness {
         Endian::Little => idx,
         #[allow(clippy::integer_arithmetic)] // idx < vec_len
         Endian::Big => vec_len - 1 - idx, // reverse order of bits

src/tools/miri/src/shims/os_str.rs

@@ -329,7 +329,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
             match direction {
                 PathConversion::HostToTarget => {
                     // If this start withs a `\`, we add `\\?` so it starts with `\\?\` which is
-                    // some magic path on Windos that *is* considered absolute.
+                    // some magic path on Windows that *is* considered absolute.
                     if converted.get(0).copied() == Some(b'\\') {
                         converted.splice(0..0, b"\\\\?".iter().copied());
                     }

src/tools/miri/src/shims/time.rs

@@ -40,7 +40,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
                     this.eval_libc_i32("CLOCK_REALTIME_COARSE"),
                 ];
                 // The second kind is MONOTONIC clocks for which 0 is an arbitrary time point, but they are
-                // never allowed to go backwards. We don't need to do any additonal monotonicity
+                // never allowed to go backwards. We don't need to do any additional monotonicity
                 // enforcement because std::time::Instant already guarantees that it is monotonic.
                 relative_clocks = vec![
                     this.eval_libc_i32("CLOCK_MONOTONIC"),

src/tools/miri/src/shims/tls.rs

@@ -79,7 +79,7 @@ impl<'tcx> TlsData<'tcx> {
                 trace!("TLS key {} removed", key);
                 Ok(())
             }
-            None => throw_ub_format!("removing a non-existig TLS key: {}", key),
+            None => throw_ub_format!("removing a nonexistent TLS key: {}", key),
         }
     }
 
@@ -175,7 +175,7 @@ impl<'tcx> TlsData<'tcx> {
             Some(key) => Excluded(key),
             None => Unbounded,
         };
-        // We interpret the documentaion above (taken from POSIX) as saying that we need to iterate
+        // We interpret the documentation above (taken from POSIX) as saying that we need to iterate
         // over all keys and run each destructor at least once before running any destructor a 2nd
         // time. That's why we have `key` to indicate how far we got in the current iteration. If we
         // return `None`, `schedule_next_pthread_tls_dtor` will re-try with `ket` set to `None` to

src/tools/miri/src/shims/unix/fs.rs

@@ -11,6 +11,7 @@ use std::time::SystemTime;
 use log::trace;
 
 use rustc_data_structures::fx::FxHashMap;
+use rustc_middle::ty::TyCtxt;
 use rustc_target::abi::{Align, Size};
 
 use crate::shims::os_str::bytes_to_os_str;
@@ -31,6 +32,7 @@ pub trait FileDescriptor: std::fmt::Debug + helpers::AsAny {
         &mut self,
         _communicate_allowed: bool,
         _bytes: &mut [u8],
+        _tcx: TyCtxt<'tcx>,
     ) -> InterpResult<'tcx, io::Result<usize>> {
         throw_unsup_format!("cannot read from {}", self.name());
     }
@@ -39,6 +41,7 @@ pub trait FileDescriptor: std::fmt::Debug + helpers::AsAny {
         &self,
         _communicate_allowed: bool,
         _bytes: &[u8],
+        _tcx: TyCtxt<'tcx>,
     ) -> InterpResult<'tcx, io::Result<usize>> {
         throw_unsup_format!("cannot write to {}", self.name());
     }
@@ -79,6 +82,7 @@ impl FileDescriptor for FileHandle {
         &mut self,
         communicate_allowed: bool,
         bytes: &mut [u8],
+        _tcx: TyCtxt<'tcx>,
     ) -> InterpResult<'tcx, io::Result<usize>> {
         assert!(communicate_allowed, "isolation should have prevented even opening a file");
         Ok(self.file.read(bytes))
@@ -88,6 +92,7 @@ impl FileDescriptor for FileHandle {
         &self,
         communicate_allowed: bool,
         bytes: &[u8],
+        _tcx: TyCtxt<'tcx>,
     ) -> InterpResult<'tcx, io::Result<usize>> {
         assert!(communicate_allowed, "isolation should have prevented even opening a file");
         Ok((&mut &self.file).write(bytes))
@@ -153,6 +158,7 @@ impl FileDescriptor for io::Stdin {
         &mut self,
         communicate_allowed: bool,
         bytes: &mut [u8],
+        _tcx: TyCtxt<'tcx>,
     ) -> InterpResult<'tcx, io::Result<usize>> {
         if !communicate_allowed {
             // We want isolation mode to be deterministic, so we have to disallow all reads, even stdin.
@@ -184,6 +190,7 @@ impl FileDescriptor for io::Stdout {
         &self,
         _communicate_allowed: bool,
         bytes: &[u8],
+        _tcx: TyCtxt<'tcx>,
     ) -> InterpResult<'tcx, io::Result<usize>> {
         // We allow writing to stderr even with isolation enabled.
         let result = Write::write(&mut { self }, bytes);
@@ -220,6 +227,7 @@ impl FileDescriptor for io::Stderr {
         &self,
         _communicate_allowed: bool,
         bytes: &[u8],
+        _tcx: TyCtxt<'tcx>,
     ) -> InterpResult<'tcx, io::Result<usize>> {
         // We allow writing to stderr even with isolation enabled.
         // No need to flush, stderr is not buffered.
@@ -252,6 +260,7 @@ impl FileDescriptor for NullOutput {
         &self,
         _communicate_allowed: bool,
         bytes: &[u8],
+        _tcx: TyCtxt<'tcx>,
     ) -> InterpResult<'tcx, io::Result<usize>> {
         // We just don't write anything, but report to the user that we did.
         Ok(Ok(bytes.len()))
@@ -756,8 +765,9 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
             let mut bytes = vec![0; usize::try_from(count).unwrap()];
             // `File::read` never returns a value larger than `count`,
             // so this cannot fail.
-            let result =
-                file_descriptor.read(communicate, &mut bytes)?.map(|c| i64::try_from(c).unwrap());
+            let result = file_descriptor
+                .read(communicate, &mut bytes, *this.tcx)?
+                .map(|c| i64::try_from(c).unwrap());
 
             match result {
                 Ok(read_bytes) => {
@@ -803,8 +813,9 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
 
         if let Some(file_descriptor) = this.machine.file_handler.handles.get(&fd) {
             let bytes = this.read_bytes_ptr_strip_provenance(buf, Size::from_bytes(count))?;
-            let result =
-                file_descriptor.write(communicate, bytes)?.map(|c| i64::try_from(c).unwrap());
+            let result = file_descriptor
+                .write(communicate, bytes, *this.tcx)?
+                .map(|c| i64::try_from(c).unwrap());
             this.try_unwrap_io_result(result)
         } else {
             this.handle_not_found()
@@ -1015,8 +1026,8 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
 
         let path = this.read_path_from_c_str(pathname_ptr)?.into_owned();
         // See <https://github.com/rust-lang/rust/pull/79196> for a discussion of argument sizes.
-        let at_ampty_path = this.eval_libc_i32("AT_EMPTY_PATH");
-        let empty_path_flag = flags & at_ampty_path == at_ampty_path;
+        let at_empty_path = this.eval_libc_i32("AT_EMPTY_PATH");
+        let empty_path_flag = flags & at_empty_path == at_empty_path;
         // We only support:
         // * interpreting `path` as an absolute directory,
         // * interpreting `path` as a path relative to `dirfd` when the latter is `AT_FDCWD`, or
@@ -1053,7 +1064,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
             return Ok(-1);
         }
 
-        // the `_mask_op` paramter specifies the file information that the caller requested.
+        // the `_mask_op` parameter specifies the file information that the caller requested.
         // However `statx` is allowed to return information that was not requested or to not
         // return information that was requested. This `mask` represents the information we can
         // actually provide for any target.

src/tools/miri/src/shims/unix/linux/fd.rs

@@ -152,7 +152,6 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         let _maxevents = this.read_scalar(maxevents)?.to_i32()?;
         let _timeout = this.read_scalar(timeout)?.to_i32()?;
 
-        let numevents = 0;
         if let Some(epfd) = this.machine.file_handler.handles.get_mut(&epfd) {
             let _epfd = epfd
                 .as_any_mut()
@@ -160,7 +159,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
                 .ok_or_else(|| err_unsup_format!("non-epoll FD passed to `epoll_wait`"))?;
 
             // FIXME return number of events ready when scheme for marking events ready exists
-            Ok(Scalar::from_i32(numevents))
+            throw_unsup_format!("returning ready events from epoll_wait is not yet implemented");
         } else {
             Ok(Scalar::from_i32(this.handle_not_found()?))
         }

src/tools/miri/src/shims/unix/linux/fd/event.rs

@@ -1,6 +1,8 @@
 use crate::shims::unix::fs::FileDescriptor;
 
 use rustc_const_eval::interpret::InterpResult;
+use rustc_middle::ty::TyCtxt;
+use rustc_target::abi::Endian;
 
 use std::cell::Cell;
 use std::io;
@@ -36,7 +38,7 @@ impl FileDescriptor for Event {
     }
 
     /// A write call adds the 8-byte integer value supplied in
-    /// its buffer to the counter.  The maximum value that may be
+    /// its buffer (in native endianess) to the counter.  The maximum value that may be
     /// stored in the counter is the largest unsigned 64-bit value
     /// minus 1 (i.e., 0xfffffffffffffffe).  If the addition would
     /// cause the counter's value to exceed the maximum, then the
@@ -47,17 +49,22 @@ impl FileDescriptor for Event {
     /// A write fails with the error EINVAL if the size of the
     /// supplied buffer is less than 8 bytes, or if an attempt is
     /// made to write the value 0xffffffffffffffff.
-    ///
-    /// FIXME: use endianness
     fn write<'tcx>(
         &self,
         _communicate_allowed: bool,
         bytes: &[u8],
+        tcx: TyCtxt<'tcx>,
     ) -> InterpResult<'tcx, io::Result<usize>> {
         let v1 = self.val.get();
+        let bytes: [u8; 8] = bytes.try_into().unwrap(); // FIXME fail gracefully when this has the wrong size
+        // Convert from target endianess to host endianess.
+        let num = match tcx.sess.target.endian {
+            Endian::Little => u64::from_le_bytes(bytes),
+            Endian::Big => u64::from_be_bytes(bytes),
+        };
         // FIXME handle blocking when addition results in exceeding the max u64 value
         // or fail with EAGAIN if the file descriptor is nonblocking.
-        let v2 = v1.checked_add(u64::from_be_bytes(bytes.try_into().unwrap())).unwrap();
+        let v2 = v1.checked_add(num).unwrap();
         self.val.set(v2);
         assert_eq!(8, bytes.len());
         Ok(Ok(8))

src/tools/miri/src/shims/unix/linux/foreign_items.rs

@@ -2,6 +2,7 @@ use rustc_span::Symbol;
 use rustc_target::spec::abi::Abi;
 
 use crate::machine::SIGRTMAX;
+use crate::machine::SIGRTMIN;
 use crate::*;
 use shims::foreign_items::EmulateByNameResult;
 use shims::unix::fs::EvalContextExt as _;
@@ -74,6 +75,11 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
                 let result = this.socketpair(domain, type_, protocol, sv)?;
                 this.write_scalar(result, dest)?;
             }
+            "__libc_current_sigrtmin" => {
+                let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
+
+                this.write_scalar(Scalar::from_i32(SIGRTMIN), dest)?;
+            }
             "__libc_current_sigrtmax" => {
                 let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
 
@@ -163,7 +169,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
                             this.linux_statx(&args[1], &args[2], &args[3], &args[4], &args[5])?;
                         this.write_scalar(Scalar::from_target_isize(result.into(), this), dest)?;
                     }
-                    // `futex` is used by some synchonization primitives.
+                    // `futex` is used by some synchronization primitives.
                     id if id == sys_futex => {
                         futex(this, &args[1..], dest)?;
                     }
@@ -174,7 +180,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
                 }
             }
 
-            // Miscelanneous
+            // Miscellaneous
             "getrandom" => {
                 let [ptr, len, flags] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;

src/tools/miri/src/shims/unix/sync.rs

@@ -242,7 +242,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
             //
             // To distinguish these two cases in already constructed mutexes, we
             // use the same trick as glibc: for the case when
-            // `pthread_mutexattr_settype` is caled explicitly, we set the
+            // `pthread_mutexattr_settype` is called explicitly, we set the
             // `PTHREAD_MUTEX_NORMAL_FLAG` flag.
             let normal_kind = kind | PTHREAD_MUTEX_NORMAL_FLAG;
             // Check that after setting the flag, the kind is distinguishable

src/tools/miri/src/shims/windows/foreign_items.rs

@@ -96,7 +96,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
 
                 if byte_offset != 0 {
                     throw_unsup_format!(
-                        "`NtWriteFile` `ByteOffset` paremeter is non-null, which is unsupported"
+                        "`NtWriteFile` `ByteOffset` parameter is non-null, which is unsupported"
                     );
                 }
 

src/tools/miri/tests/compiletest.rs

@@ -2,7 +2,7 @@ use colored::*;
 use regex::bytes::Regex;
 use std::path::{Path, PathBuf};
 use std::{env, process::Command};
-use ui_test::{color_eyre::Result, Config, Mode, OutputConflictHandling};
+use ui_test::{color_eyre::Result, Config, Match, Mode, OutputConflictHandling};
 
 fn miri_path() -> PathBuf {
     PathBuf::from(option_env!("MIRI").unwrap_or(env!("CARGO_BIN_EXE_miri")))
@@ -52,14 +52,13 @@ fn run_tests(mode: Mode, path: &str, target: &str, with_dependencies: bool) -> R
         mode,
         program: miri_path(),
         quiet: false,
+        edition: Some("2018".into()),
         ..Config::default()
     };
 
     let in_rustc_test_suite = option_env!("RUSTC_STAGE").is_some();
 
     // Add some flags we always want.
-    config.args.push("--edition".into());
-    config.args.push("2018".into());
     if in_rustc_test_suite {
         // Less aggressive warnings to make the rustc toolstate management less painful.
         // (We often get warnings when e.g. a feature gets stabilized or some lint gets added/improved.)
@@ -100,12 +99,24 @@ fn run_tests(mode: Mode, path: &str, target: &str, with_dependencies: bool) -> R
     };
 
     // Handle command-line arguments.
+    let mut after_dashdash = false;
     config.path_filter.extend(std::env::args().skip(1).filter(|arg| {
+        if after_dashdash {
+            // Just propagate everything.
+            return true;
+        }
         match &**arg {
             "--quiet" => {
                 config.quiet = true;
                 false
             }
+            "--" => {
+                after_dashdash = true;
+                false
+            }
+            s if s.starts_with('-') => {
+                panic!("unknown compiletest flag `{s}`");
+            }
             _ => true,
         }
     }));
@@ -129,8 +140,8 @@ fn run_tests(mode: Mode, path: &str, target: &str, with_dependencies: bool) -> R
 
 macro_rules! regexes {
     ($name:ident: $($regex:expr => $replacement:expr,)*) => {lazy_static::lazy_static! {
-        static ref $name: Vec<(Regex, &'static [u8])> = vec![
-            $((Regex::new($regex).unwrap(), $replacement.as_bytes()),)*
+        static ref $name: Vec<(Match, &'static [u8])> = vec![
+            $((Regex::new($regex).unwrap().into(), $replacement.as_bytes()),)*
         ];
     }};
 }

src/tools/miri/tests/fail/intrinsics/exact_div1.rs

@@ -1,5 +1,5 @@
 #![feature(core_intrinsics)]
 fn main() {
-    // divison by 0
+    // division by 0
     unsafe { std::intrinsics::exact_div(2, 0) }; //~ ERROR: divisor of zero
 }

src/tools/miri/tests/fail/intrinsics/exact_div2.rs

@@ -1,5 +1,5 @@
 #![feature(core_intrinsics)]
 fn main() {
-    // divison with a remainder
+    // division with a remainder
     unsafe { std::intrinsics::exact_div(2u16, 3) }; //~ ERROR: 2_u16 cannot be divided by 3_u16 without remainder
 }

src/tools/miri/tests/fail/intrinsics/exact_div3.rs

@@ -1,5 +1,5 @@
 #![feature(core_intrinsics)]
 fn main() {
-    // signed divison with a remainder
+    // signed division with a remainder
     unsafe { std::intrinsics::exact_div(-19i8, 2) }; //~ ERROR: -19_i8 cannot be divided by 2_i8 without remainder
 }

src/tools/miri/tests/fail/intrinsics/exact_div4.rs

@@ -1,5 +1,5 @@
 #![feature(core_intrinsics)]
 fn main() {
-    // divison of MIN by -1
+    // division of MIN by -1
     unsafe { std::intrinsics::exact_div(i64::MIN, -1) }; //~ ERROR: overflow in signed remainder (dividing MIN by -1)
 }

src/tools/miri/tests/fail/panic/double_panic.rs

@@ -1,6 +1,8 @@
 //@error-pattern: the program aborted
 //@normalize-stderr-test: "\| +\^+" -> "| ^"
 //@normalize-stderr-test: "unsafe \{ libc::abort\(\) \}|crate::intrinsics::abort\(\);" -> "ABORT();"
+//@normalize-stderr-test: "\n  +[0-9]+:[^\n]+" -> "$1"
+//@normalize-stderr-test: "\n at [^\n]+" -> "$1"
 
 struct Foo;
 impl Drop for Foo {

src/tools/miri/tests/fail/panic/double_panic.stderr

@@ -2,70 +2,6 @@ thread 'main' panicked at 'first', $DIR/double_panic.rs:LL:CC
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 thread 'main' panicked at 'second', $DIR/double_panic.rs:LL:CC
 stack backtrace:
-   0: std::backtrace_rs::backtrace::miri::trace_unsynchronized
- at RUSTLIB/std/src/../../backtrace/src/backtrace/miri.rs:LL:CC
-   1: std::backtrace_rs::backtrace::miri::trace
- at RUSTLIB/std/src/../../backtrace/src/backtrace/miri.rs:LL:CC
-   2: std::backtrace_rs::backtrace::trace_unsynchronized
- at RUSTLIB/std/src/../../backtrace/src/backtrace/mod.rs:LL:CC
-   3: std::sys_common::backtrace::_print_fmt
- at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
-   4: <std::sys_common::backtrace::_print::DisplayBacktrace as std::fmt::Display>::fmt
- at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
-   5: core::fmt::rt::Argument::fmt
- at RUSTLIB/core/src/fmt/rt.rs:LL:CC
-   6: std::fmt::write
- at RUSTLIB/core/src/fmt/mod.rs:LL:CC
-   7: <std::sys::PLATFORM::stdio::Stderr as std::io::Write>::write_fmt
- at RUSTLIB/std/src/io/mod.rs:LL:CC
-   8: std::sys_common::backtrace::_print
- at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
-   9: std::sys_common::backtrace::print
- at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
-  10: std::panicking::default_hook::{closure#1}
- at RUSTLIB/std/src/panicking.rs:LL:CC
-  11: std::panicking::default_hook
- at RUSTLIB/std/src/panicking.rs:LL:CC
-  12: std::panicking::rust_panic_with_hook
- at RUSTLIB/std/src/panicking.rs:LL:CC
-  13: std::rt::begin_panic::{closure#0}
- at RUSTLIB/std/src/panicking.rs:LL:CC
-  14: std::sys_common::backtrace::__rust_end_short_backtrace
- at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
-  15: std::rt::begin_panic
- at RUSTLIB/std/src/panicking.rs:LL:CC
-  16: <Foo as std::ops::Drop>::drop
- at $DIR/double_panic.rs:LL:CC
-  17: std::ptr::drop_in_place - shim(Some(Foo))
- at RUSTLIB/core/src/ptr/mod.rs:LL:CC
-  18: main
- at $DIR/double_panic.rs:LL:CC
-  19: <fn() as std::ops::FnOnce<()>>::call_once - shim(fn())
- at RUSTLIB/core/src/ops/function.rs:LL:CC
-  20: std::sys_common::backtrace::__rust_begin_short_backtrace
- at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
-  21: std::rt::lang_start::{closure#0}
- at RUSTLIB/std/src/rt.rs:LL:CC
-  22: std::ops::function::impls::call_once
- at RUSTLIB/core/src/ops/function.rs:LL:CC
-  23: std::panicking::r#try::do_call
- at RUSTLIB/std/src/panicking.rs:LL:CC
-  24: std::panicking::r#try
- at RUSTLIB/std/src/panicking.rs:LL:CC
-  25: std::panic::catch_unwind
- at RUSTLIB/std/src/panic.rs:LL:CC
-  26: std::rt::lang_start_internal::{closure#2}
- at RUSTLIB/std/src/rt.rs:LL:CC
-  27: std::panicking::r#try::do_call
- at RUSTLIB/std/src/panicking.rs:LL:CC
-  28: std::panicking::r#try
- at RUSTLIB/std/src/panicking.rs:LL:CC
-  29: std::panic::catch_unwind
- at RUSTLIB/std/src/panic.rs:LL:CC
-  30: std::rt::lang_start_internal
- at RUSTLIB/std/src/rt.rs:LL:CC
-  31: std::rt::lang_start
- at RUSTLIB/std/src/rt.rs:LL:CC
 thread panicked while panicking. aborting.
 error: abnormal termination: the program aborted execution
   --> RUSTLIB/std/src/sys/PLATFORM/mod.rs:LL:CC

src/tools/miri/tests/fail/stacked_borrows/illegal_read3.rs

@@ -1,5 +1,5 @@
 // A callee may not read the destination of our `&mut` without us noticing.
-// Thise code got carefully checked to not introduce any reborrows
+// This code got carefully checked to not introduce any reborrows
 // that are not explicit in the source. Let's hope the compiler does not break this later!
 
 use std::mem;

src/tools/miri/tests/fail/terminate-terminator.rs

@@ -12,14 +12,13 @@ impl Drop for Foo {
 
 #[inline(always)]
 fn has_cleanup() {
-    //~^ ERROR: panic in a function that cannot unwind
-    // FIXME(nbdd0121): The error should be reported at the call site.
     let _f = Foo;
     panic!();
 }
 
 extern "C" fn panic_abort() {
     has_cleanup();
+    //~^ ERROR: panic in a function that cannot unwind
 }
 
 fn main() {

src/tools/miri/tests/fail/terminate-terminator.stderr

@@ -6,8 +6,6 @@ error: abnormal termination: panic in a function that cannot unwind
   --> $DIR/terminate-terminator.rs:LL:CC
    |
 LL | / fn has_cleanup() {
-LL | |
-LL | |     // FIXME(nbdd0121): The error should be reported at the call site.
 LL | |     let _f = Foo;
 LL | |     panic!();
 LL | | }

src/tools/miri/tests/fail/tokio/sleep.rs

@@ -1,5 +1,7 @@
 //@compile-flags: -Zmiri-permissive-provenance -Zmiri-backtrace=full
 //@only-target-x86_64-unknown-linux: support for tokio only on linux and x86
+//@error-pattern: returning ready events from epoll_wait is not yet implemented
+//@normalize-stderr-test: " += note:.*\n" -> ""
 
 use tokio::time::{sleep, Duration, Instant};
 

src/tools/miri/tests/fail/tokio/sleep.stderr

@@ -0,0 +1,15 @@
+error: unsupported operation: returning ready events from epoll_wait is not yet implemented
+  --> CARGO_REGISTRY/.../epoll.rs:LL:CC
+   |
+LL | /         syscall!(epoll_wait(
+LL | |             self.ep,
+LL | |             events.as_mut_ptr(),
+LL | |             events.capacity() as i32,
+LL | |             timeout,
+LL | |         ))
+   | |__________^ returning ready events from epoll_wait is not yet implemented
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that the interpreter does not support
+
+error: aborting due to previous error
+

src/tools/miri/tests/fail/tree-borrows/alternate-read-write.stderr

@@ -1,11 +1,35 @@
-error: Undefined Behavior: write access through <TAG> is forbidden because it is a child of <TAG> which is Frozen.
+error: Undefined Behavior: write access through <TAG> is forbidden
   --> $DIR/alternate-read-write.rs:LL:CC
    |
 LL |     *y += 1; // Failure
-   |     ^^^^^^^ write access through <TAG> is forbidden because it is a child of <TAG> which is Frozen.
+   |     ^^^^^^^ write access through <TAG> is forbidden
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Tree Borrows rules it violated are still experimental
-   = note: BACKTRACE:
+   = help: the accessed tag <TAG> is a child of the conflicting tag <TAG>
+   = help: the conflicting tag <TAG> has state Frozen which forbids child write accesses
+help: the accessed tag <TAG> was created here
+  --> $DIR/alternate-read-write.rs:LL:CC
+   |
+LL |     let y = unsafe { &mut *(x as *mut u8) };
+   |                      ^^^^^^^^^^^^^^^^^^^^
+help: the conflicting tag <TAG> was created here, in the initial state Reserved
+  --> $DIR/alternate-read-write.rs:LL:CC
+   |
+LL |     let y = unsafe { &mut *(x as *mut u8) };
+   |                      ^^^^^^^^^^^^^^^^^^^^
+help: the conflicting tag <TAG> then transitioned from Reserved to Active due to a child write access at offsets [0x0..0x1]
+  --> $DIR/alternate-read-write.rs:LL:CC
+   |
+LL |     *y += 1; // Success
+   |     ^^^^^^^
+   = help: this corresponds to an activation
+help: the conflicting tag <TAG> then transitioned from Active to Frozen due to a foreign read access at offsets [0x0..0x1]
+  --> $DIR/alternate-read-write.rs:LL:CC
+   |
+LL |     let _val = *x;
+   |                ^^
+   = help: this corresponds to a loss of write permissions
+   = note: BACKTRACE (of the first span):
    = note: inside `main` at $DIR/alternate-read-write.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

src/tools/miri/tests/fail/tree-borrows/error-range.rs

@@ -0,0 +1,27 @@
+//@compile-flags: -Zmiri-tree-borrows
+
+use core::ptr::addr_of_mut;
+
+// Check that the diagnostics correctly report the exact range at fault
+// and trim irrelevant events.
+fn main() {
+    unsafe {
+        let data = &mut [0u8; 16];
+
+        // Create and activate a few bytes
+        let rmut = &mut *addr_of_mut!(data[0..6]);
+        rmut[3] += 1;
+        rmut[4] += 1;
+        rmut[5] += 1;
+
+        // Now make them lose some perms
+        let _v = data[3];
+        let _v = data[4];
+        let _v = data[5];
+        data[4] = 1;
+        data[5] = 1;
+
+        // Final test
+        rmut[5] += 1; //~ ERROR: /read access through .* is forbidden/
+    }
+}

src/tools/miri/tests/fail/tree-borrows/error-range.stderr

@@ -0,0 +1,44 @@
+error: Undefined Behavior: read access through <TAG> is forbidden
+  --> $DIR/error-range.rs:LL:CC
+   |
+LL |         rmut[5] += 1;
+   |         ^^^^^^^^^^^^ read access through <TAG> is forbidden
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Tree Borrows rules it violated are still experimental
+   = help: the accessed tag <TAG> is a child of the conflicting tag <TAG>
+   = help: the conflicting tag <TAG> has state Disabled which forbids child read accesses
+help: the accessed tag <TAG> was created here
+  --> $DIR/error-range.rs:LL:CC
+   |
+LL |         let rmut = &mut *addr_of_mut!(data[0..6]);
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: the conflicting tag <TAG> was created here, in the initial state Reserved
+  --> $DIR/error-range.rs:LL:CC
+   |
+LL |         let rmut = &mut *addr_of_mut!(data[0..6]);
+   |                                       ^^^^
+help: the conflicting tag <TAG> then transitioned from Reserved to Active due to a child write access at offsets [0x5..0x6]
+  --> $DIR/error-range.rs:LL:CC
+   |
+LL |         rmut[5] += 1;
+   |         ^^^^^^^^^^^^
+   = help: this corresponds to an activation
+help: the conflicting tag <TAG> then transitioned from Active to Frozen due to a foreign read access at offsets [0x5..0x6]
+  --> $DIR/error-range.rs:LL:CC
+   |
+LL |         let _v = data[5];
+   |                  ^^^^^^^
+   = help: this corresponds to a loss of write permissions
+help: the conflicting tag <TAG> then transitioned from Frozen to Disabled due to a foreign write access at offsets [0x5..0x6]
+  --> $DIR/error-range.rs:LL:CC
+   |
+LL |         data[5] = 1;
+   |         ^^^^^^^^^^^
+   = help: this corresponds to a loss of read permissions
+   = note: BACKTRACE (of the first span):
+   = note: inside `main` at $DIR/error-range.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+

src/tools/miri/tests/fail/tree-borrows/fragile-data-race.stderr

@@ -1,11 +1,29 @@
-error: Undefined Behavior: write access through <TAG> is forbidden because it is a child of <TAG> which is Frozen.
+error: Undefined Behavior: write access through <TAG> is forbidden
   --> $DIR/fragile-data-race.rs:LL:CC
    |
 LL |     unsafe { *p = 1 };
-   |              ^^^^^^ write access through <TAG> is forbidden because it is a child of <TAG> which is Frozen.
+   |              ^^^^^^ write access through <TAG> is forbidden
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Tree Borrows rules it violated are still experimental
-   = note: BACKTRACE:
+   = help: the accessed tag <TAG> is a child of the conflicting tag <TAG>
+   = help: the conflicting tag <TAG> has state Frozen which forbids child write accesses
+help: the accessed tag <TAG> was created here
+  --> $DIR/fragile-data-race.rs:LL:CC
+   |
+LL | fn thread_1(x: &mut u8) -> SendPtr {
+   |             ^
+help: the conflicting tag <TAG> was created here, in the initial state Reserved
+  --> RUSTLIB/std/src/panic.rs:LL:CC
+   |
+LL | pub fn catch_unwind<F: FnOnce() -> R + UnwindSafe, R>(f: F) -> Result<R> {
+   |                                                       ^
+help: the conflicting tag <TAG> then transitioned from Reserved to Frozen due to a foreign read access at offsets [0x0..0x1]
+  --> RUSTLIB/core/src/ptr/mod.rs:LL:CC
+   |
+LL |         crate::intrinsics::read_via_copy(src)
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = help: this corresponds to a loss of write permissions
+   = note: BACKTRACE (of the first span):
    = note: inside `main` at $DIR/fragile-data-race.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

src/tools/miri/tests/fail/tree-borrows/outside-range.stderr

@@ -1,11 +1,24 @@
-error: Undefined Behavior: write access through <TAG> is forbidden because it is a foreign tag for <TAG>, which would hence change from Reserved to Disabled, but <TAG> is protected
+error: Undefined Behavior: write access through <TAG> is forbidden
   --> $DIR/outside-range.rs:LL:CC
    |
 LL |     *y.add(3) = 42;
-   |     ^^^^^^^^^^^^^^ write access through <TAG> is forbidden because it is a foreign tag for <TAG>, which would hence change from Reserved to Disabled, but <TAG> is protected
+   |     ^^^^^^^^^^^^^^ write access through <TAG> is forbidden
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Tree Borrows rules it violated are still experimental
-   = note: BACKTRACE:
+   = help: the accessed tag <TAG> is foreign to the protected tag <TAG> (i.e., it is not a child)
+   = help: the access would cause the protected tag <TAG> to transition from Reserved to Disabled
+   = help: this is a loss of read and write permissions, which is not allowed for protected tags
+help: the accessed tag <TAG> was created here
+  --> $DIR/outside-range.rs:LL:CC
+   |
+LL |         let raw = data.as_mut_ptr();
+   |                   ^^^^^^^^^^^^^^^^^
+help: the protected tag <TAG> was created here, in the initial state Reserved
+  --> $DIR/outside-range.rs:LL:CC
+   |
+LL | unsafe fn stuff(x: &mut u8, y: *mut u8) {
+   |                 ^
+   = note: BACKTRACE (of the first span):
    = note: inside `stuff` at $DIR/outside-range.rs:LL:CC
 note: inside `main`
   --> $DIR/outside-range.rs:LL:CC

src/tools/miri/tests/fail/tree-borrows/read-to-local.stderr

@@ -1,12 +1,31 @@
-error: Undefined Behavior: write access through <TAG> is forbidden because it is a child of <TAG> which is Frozen.
+error: Undefined Behavior: write access through <TAG> is forbidden
   --> $DIR/read-to-local.rs:LL:CC
    |
 LL |         *ptr = 0;
-   |         ^^^^^^^^ write access through <TAG> is forbidden because it is a child of <TAG> which is Frozen.
+   |         ^^^^^^^^ write access through <TAG> is forbidden
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Tree Borrows rules it violated are still experimental
-   = note: BACKTRACE:
+   = help: the accessed tag <TAG> has state Frozen which forbids child write accesses
+help: the accessed tag <TAG> was created here, in the initial state Reserved
+  --> $DIR/read-to-local.rs:LL:CC
+   |
+LL |         let mref = &mut root;
+   |                    ^^^^^^^^^
+help: the accessed tag <TAG> then transitioned from Reserved to Active due to a child write access at offsets [0x0..0x1]
+  --> $DIR/read-to-local.rs:LL:CC
+   |
+LL |         *ptr = 0; // Write
+   |         ^^^^^^^^
+   = help: this corresponds to an activation
+help: the accessed tag <TAG> then transitioned from Active to Frozen due to a foreign read access at offsets [0x0..0x1]
+  --> $DIR/read-to-local.rs:LL:CC
+   |
+LL |         assert_eq!(root, 0); // Parent Read
+   |         ^^^^^^^^^^^^^^^^^^^
+   = help: this corresponds to a loss of write permissions
+   = note: BACKTRACE (of the first span):
    = note: inside `main` at $DIR/read-to-local.rs:LL:CC
+   = note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 

src/tools/miri/tests/fail/tree-borrows/reserved/cell-protected-write.stderr

@@ -1,20 +1,34 @@
 ──────────────────────────────────────────────────────────────────────
 Warning: this tree is indicative only. Some tags may have been hidden.
 0..  1
+| Act|    └─┬──<TAG=root of the allocation>
 | Re*|      └─┬──<TAG=base>
 | Re*|        ├─┬──<TAG=x>
 | Re*|        │ └─┬──<TAG=caller:x>
 | Re*|        │   └────<TAG=callee:x> Strongly protected
 | Re*|        └────<TAG=y, callee:y, caller:y>
 ──────────────────────────────────────────────────────────────────────
-error: Undefined Behavior: write access through <TAG> (also named 'y,callee:y,caller:y') is forbidden because it is a foreign tag for <TAG> (also named 'callee:x'), which would hence change from Reserved to Disabled, but <TAG> (also named 'callee:x') is protected
+error: Undefined Behavior: write access through <TAG> (y, callee:y, caller:y) is forbidden
   --> $DIR/cell-protected-write.rs:LL:CC
    |
 LL |             *y = 1;
-   |             ^^^^^^ write access through <TAG> (also named 'y,callee:y,caller:y') is forbidden because it is a foreign tag for <TAG> (also named 'callee:x'), which would hence change from Reserved to Disabled, but <TAG> (also named 'callee:x') is protected
+   |             ^^^^^^ write access through <TAG> (y, callee:y, caller:y) is forbidden
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Tree Borrows rules it violated are still experimental
-   = note: BACKTRACE:
+   = help: the accessed tag <TAG> (y, callee:y, caller:y) is foreign to the protected tag <TAG> (callee:x) (i.e., it is not a child)
+   = help: the access would cause the protected tag <TAG> (callee:x) to transition from Reserved to Disabled
+   = help: this is a loss of read and write permissions, which is not allowed for protected tags
+help: the accessed tag <TAG> was created here
+  --> $DIR/cell-protected-write.rs:LL:CC
+   |
+LL |         let y = (&mut *n).get();
+   |                 ^^^^^^^^^
+help: the protected tag <TAG> was created here, in the initial state Reserved
+  --> $DIR/cell-protected-write.rs:LL:CC
+   |
+LL |         unsafe fn write_second(x: &mut UnsafeCell<u8>, y: *mut u8) {
+   |                                ^
+   = note: BACKTRACE (of the first span):
    = note: inside `main::write_second` at $DIR/cell-protected-write.rs:LL:CC
 note: inside `main`
   --> $DIR/cell-protected-write.rs:LL:CC

src/tools/miri/tests/fail/tree-borrows/reserved/int-protected-write.stderr

@@ -1,20 +1,34 @@
 ──────────────────────────────────────────────────────────────────────
 Warning: this tree is indicative only. Some tags may have been hidden.
 0..  1
+| Act|    └─┬──<TAG=root of the allocation>
 | Res|      └─┬──<TAG=n>
 | Res|        ├─┬──<TAG=x>
 | Res|        │ └─┬──<TAG=caller:x>
 | Res|        │   └────<TAG=callee:x> Strongly protected
 | Res|        └────<TAG=y, callee:y, caller:y>
 ──────────────────────────────────────────────────────────────────────
-error: Undefined Behavior: write access through <TAG> (also named 'y,callee:y,caller:y') is forbidden because it is a foreign tag for <TAG> (also named 'callee:x'), which would hence change from Reserved to Disabled, but <TAG> (also named 'callee:x') is protected
+error: Undefined Behavior: write access through <TAG> (y, callee:y, caller:y) is forbidden
   --> $DIR/int-protected-write.rs:LL:CC
    |
 LL |             *y = 0;
-   |             ^^^^^^ write access through <TAG> (also named 'y,callee:y,caller:y') is forbidden because it is a foreign tag for <TAG> (also named 'callee:x'), which would hence change from Reserved to Disabled, but <TAG> (also named 'callee:x') is protected
+   |             ^^^^^^ write access through <TAG> (y, callee:y, caller:y) is forbidden
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Tree Borrows rules it violated are still experimental
-   = note: BACKTRACE:
+   = help: the accessed tag <TAG> (y, callee:y, caller:y) is foreign to the protected tag <TAG> (callee:x) (i.e., it is not a child)
+   = help: the access would cause the protected tag <TAG> (callee:x) to transition from Reserved to Disabled
+   = help: this is a loss of read and write permissions, which is not allowed for protected tags
+help: the accessed tag <TAG> was created here
+  --> $DIR/int-protected-write.rs:LL:CC
+   |
+LL |         let y = (&mut *n) as *mut _;
+   |                 ^^^^^^^^^
+help: the protected tag <TAG> was created here, in the initial state Reserved
+  --> $DIR/int-protected-write.rs:LL:CC
+   |
+LL |         unsafe fn write_second(x: &mut u8, y: *mut u8) {
+   |                                ^
+   = note: BACKTRACE (of the first span):
    = note: inside `main::write_second` at $DIR/int-protected-write.rs:LL:CC
 note: inside `main`
   --> $DIR/int-protected-write.rs:LL:CC

src/tools/miri/tests/fail/tree-borrows/strongly-protected.rs

@@ -0,0 +1,14 @@
+//@compile-flags: -Zmiri-tree-borrows
+//@error-pattern: /deallocation through .* is forbidden/
+
+fn inner(x: &mut i32, f: fn(&mut i32)) {
+    // `f` may mutate, but it may not deallocate!
+    f(x)
+}
+
+fn main() {
+    inner(Box::leak(Box::new(0)), |x| {
+        let raw = x as *mut _;
+        drop(unsafe { Box::from_raw(raw) });
+    });
+}

src/tools/miri/tests/fail/tree-borrows/strongly-protected.stderr

@@ -0,0 +1,49 @@
+error: Undefined Behavior: deallocation through <TAG> is forbidden
+  --> RUSTLIB/alloc/src/alloc.rs:LL:CC
+   |
+LL |     unsafe { __rust_dealloc(ptr, layout.size(), layout.align()) }
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ deallocation through <TAG> is forbidden
+   |
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Tree Borrows rules it violated are still experimental
+   = help: the allocation of the accessed tag <TAG> also contains the strongly protected tag <TAG>
+   = help: the strongly protected tag <TAG> disallows deallocations
+help: the accessed tag <TAG> was created here
+  --> $DIR/strongly-protected.rs:LL:CC
+   |
+LL |         drop(unsafe { Box::from_raw(raw) });
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: the strongly protected tag <TAG> was created here, in the initial state Reserved
+  --> $DIR/strongly-protected.rs:LL:CC
+   |
+LL | fn inner(x: &mut i32, f: fn(&mut i32)) {
+   |          ^
+   = note: BACKTRACE (of the first span):
+   = note: inside `std::alloc::dealloc` at RUSTLIB/alloc/src/alloc.rs:LL:CC
+   = note: inside `<std::alloc::Global as std::alloc::Allocator>::deallocate` at RUSTLIB/alloc/src/alloc.rs:LL:CC
+   = note: inside `alloc::alloc::box_free::<i32, std::alloc::Global>` at RUSTLIB/alloc/src/alloc.rs:LL:CC
+   = note: inside `std::ptr::drop_in_place::<std::boxed::Box<i32>> - shim(Some(std::boxed::Box<i32>))` at RUSTLIB/core/src/ptr/mod.rs:LL:CC
+   = note: inside `std::mem::drop::<std::boxed::Box<i32>>` at RUSTLIB/core/src/mem/mod.rs:LL:CC
+note: inside closure
+  --> $DIR/strongly-protected.rs:LL:CC
+   |
+LL |         drop(unsafe { Box::from_raw(raw) });
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: inside `<[closure@$DIR/strongly-protected.rs:LL:CC] as std::ops::FnOnce<(&mut i32,)>>::call_once - shim` at RUSTLIB/core/src/ops/function.rs:LL:CC
+note: inside `inner`
+  --> $DIR/strongly-protected.rs:LL:CC
+   |
+LL |     f(x)
+   |     ^^^^
+note: inside `main`
+  --> $DIR/strongly-protected.rs:LL:CC
+   |
+LL | /     inner(Box::leak(Box::new(0)), |x| {
+LL | |         let raw = x as *mut _;
+LL | |         drop(unsafe { Box::from_raw(raw) });
+LL | |     });
+   | |______^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to previous error
+

src/tools/miri/tests/fail/tree-borrows/write-during-2phase.stderr

@@ -1,11 +1,30 @@
-error: Undefined Behavior: read access through <TAG> is forbidden because it is a child of <TAG> which is Disabled.
+error: Undefined Behavior: read access through <TAG> is forbidden
   --> $DIR/write-during-2phase.rs:LL:CC
    |
 LL |     fn add(&mut self, n: u64) -> u64 {
-   |            ^^^^^^^^^ read access through <TAG> is forbidden because it is a child of <TAG> which is Disabled.
+   |            ^^^^^^^^^ read access through <TAG> is forbidden
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Tree Borrows rules it violated are still experimental
-   = note: BACKTRACE:
+   = help: the accessed tag <TAG> has state Disabled which forbids child read accesses
+help: the accessed tag <TAG> was created here, in the initial state Reserved
+  --> $DIR/write-during-2phase.rs:LL:CC
+   |
+LL |       let _res = f.add(unsafe {
+   |  ________________^
+LL | |         let n = f.0;
+LL | |         // This is the access at fault, but it's not immediately apparent because
+LL | |         // the reference that got invalidated is not under a Protector.
+LL | |         *inner = 42;
+LL | |         n
+LL | |     });
+   | |______^
+help: the accessed tag <TAG> then transitioned from Reserved to Disabled due to a foreign write access at offsets [0x0..0x8]
+  --> $DIR/write-during-2phase.rs:LL:CC
+   |
+LL |         *inner = 42;
+   |         ^^^^^^^^^^^
+   = help: this corresponds to a loss of read and write permissions
+   = note: BACKTRACE (of the first span):
    = note: inside `Foo::add` at $DIR/write-during-2phase.rs:LL:CC
 note: inside `main`
   --> $DIR/write-during-2phase.rs:LL:CC

src/tools/miri/tests/fail/unaligned_pointers/intptrcast_alignment_check.rs

@@ -1,7 +1,7 @@
 //@compile-flags: -Zmiri-symbolic-alignment-check -Zmiri-permissive-provenance -Cdebug-assertions=no
 // With the symbolic alignment check, even with intptrcast and without
 // validation, we want to be *sure* to catch bugs that arise from pointers being
-// insufficiently aligned. The only way to achieve that is not not let programs
+// insufficiently aligned. The only way to achieve that is not to let programs
 // exploit integer information for alignment, so here we test that this is
 // indeed the case.
 //

src/tools/miri/tests/panic/oob_subslice.rs

@@ -0,0 +1,7 @@
+// This once failed with "unwinding past a stack frame that does not allow unwinding",
+// fixed by https://github.com/rust-lang/rust/issues/110233.
+
+fn main() {
+    let x = [1, 2, 3, 4];
+    let _val = &x[..=4];
+}

src/tools/miri/tests/panic/oob_subslice.stderr

@@ -0,0 +1,2 @@
+thread 'main' panicked at 'range end index 5 out of range for slice of length 4', $DIR/oob_subslice.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

src/tools/miri/tests/pass-dep/concurrency/tls_pthread_drop_order.rs

@@ -14,7 +14,7 @@ static mut RECORD: usize = 0;
 static mut KEYS: [Key; 2] = [0; 2];
 static mut GLOBALS: [u64; 2] = [1, 0];
 
-static mut CANNARY: *mut u64 = ptr::null_mut(); // this serves as a cannary: if TLS dtors are not run properly, this will not get deallocated, making the test fail.
+static mut CANARY: *mut u64 = ptr::null_mut(); // this serves as a canary: if TLS dtors are not run properly, this will not get deallocated, making the test fail.
 
 pub unsafe fn create(dtor: Option<unsafe extern "C" fn(*mut u8)>) -> Key {
     let mut key = 0;
@@ -33,7 +33,7 @@ pub fn record(r: usize) {
 }
 
 unsafe extern "C" fn dtor(ptr: *mut u64) {
-    assert!(CANNARY != ptr::null_mut()); // make sure we do not get run too often
+    assert!(CANARY != ptr::null_mut()); // make sure we do not get run too often
     let val = *ptr;
 
     let which_key =
@@ -45,15 +45,15 @@ unsafe extern "C" fn dtor(ptr: *mut u64) {
         set(KEYS[which_key], ptr as *mut _);
     }
 
-    // Check if the records matches what we expect. If yes, clear the cannary.
-    // If the record is wrong, the cannary will never get cleared, leading to a leak -> test fails.
+    // Check if the records matches what we expect. If yes, clear the canary.
+    // If the record is wrong, the canary will never get cleared, leading to a leak -> test fails.
     // If the record is incomplete (i.e., more dtor calls happen), the check at the beginning of this function will fail -> test fails.
     // The correct sequence is: First key 0, then key 1, then key 0.
     // Note that this relies on dtor order, which is not specified by POSIX, but seems to be
     // consistent between Miri and Linux currently (as of Aug 2022).
     if RECORD == 0_1_0 {
-        drop(Box::from_raw(CANNARY));
-        CANNARY = ptr::null_mut();
+        drop(Box::from_raw(CANARY));
+        CANARY = ptr::null_mut();
     }
 }
 
@@ -67,7 +67,7 @@ fn main() {
             set(*key, global as *mut _ as *mut u8);
         }
 
-        // Initialize cannary
-        CANNARY = Box::into_raw(Box::new(0u64));
+        // Initialize canary
+        CANARY = Box::into_raw(Box::new(0u64));
     }
 }

src/tools/miri/tests/pass-dep/shims/libc-fs.rs

@@ -130,7 +130,7 @@ fn test_readlink() {
     let mut large_buf = vec![0xFF; expected_path.len() + 1];
     let res =
         unsafe { libc::readlink(symlink_c_ptr, large_buf.as_mut_ptr().cast(), large_buf.len()) };
-    // Check that the resovled path was properly written into the buf.
+    // Check that the resolved path was properly written into the buf.
     assert_eq!(&large_buf[..(large_buf.len() - 1)], expected_path);
     assert_eq!(large_buf.last(), Some(&0xFF));
     assert_eq!(res, large_buf.len() as isize - 1);

src/tools/miri/tests/pass-dep/shims/libc-misc.rs

@@ -90,7 +90,7 @@ fn test_posix_realpath_errors() {
     use std::ffi::CString;
     use std::io::ErrorKind;
 
-    // Test non-existent path returns an error.
+    // Test nonexistent path returns an error.
     let c_path = CString::new("./nothing_to_see_here").expect("CString::new failed");
     let r = unsafe { libc::realpath(c_path.as_ptr(), std::ptr::null_mut()) };
     assert!(r.is_null());
@@ -302,6 +302,101 @@ fn test_posix_mkstemp() {
     }
 }
 
+fn test_memcpy() {
+    unsafe {
+        let src = [1i8, 2, 3];
+        let dest = libc::calloc(3, 1);
+        libc::memcpy(dest, src.as_ptr() as *const libc::c_void, 3);
+        let slc = std::slice::from_raw_parts(dest as *const i8, 3);
+        assert_eq!(*slc, [1i8, 2, 3]);
+        libc::free(dest);
+    }
+
+    unsafe {
+        let src = [1i8, 2, 3];
+        let dest = libc::calloc(4, 1);
+        libc::memcpy(dest, src.as_ptr() as *const libc::c_void, 3);
+        let slc = std::slice::from_raw_parts(dest as *const i8, 4);
+        assert_eq!(*slc, [1i8, 2, 3, 0]);
+        libc::free(dest);
+    }
+
+    unsafe {
+        let src = 123_i32;
+        let mut dest = 0_i32;
+        libc::memcpy(
+            &mut dest as *mut i32 as *mut libc::c_void,
+            &src as *const i32 as *const libc::c_void,
+            std::mem::size_of::<i32>(),
+        );
+        assert_eq!(dest, src);
+    }
+
+    unsafe {
+        let src = Some(123);
+        let mut dest: Option<i32> = None;
+        libc::memcpy(
+            &mut dest as *mut Option<i32> as *mut libc::c_void,
+            &src as *const Option<i32> as *const libc::c_void,
+            std::mem::size_of::<Option<i32>>(),
+        );
+        assert_eq!(dest, src);
+    }
+
+    unsafe {
+        let src = &123;
+        let mut dest = &42;
+        libc::memcpy(
+            &mut dest as *mut &'static i32 as *mut libc::c_void,
+            &src as *const &'static i32 as *const libc::c_void,
+            std::mem::size_of::<&'static i32>(),
+        );
+        assert_eq!(*dest, 123);
+    }
+}
+
+fn test_strcpy() {
+    use std::ffi::{CStr, CString};
+
+    // case: src_size equals dest_size
+    unsafe {
+        let src = CString::new("rust").unwrap();
+        let size = src.as_bytes_with_nul().len();
+        let dest = libc::malloc(size);
+        libc::strcpy(dest as *mut libc::c_char, src.as_ptr());
+        assert_eq!(CStr::from_ptr(dest as *const libc::c_char), src.as_ref());
+        libc::free(dest);
+    }
+
+    // case: src_size is less than dest_size
+    unsafe {
+        let src = CString::new("rust").unwrap();
+        let size = src.as_bytes_with_nul().len();
+        let dest = libc::malloc(size + 1);
+        libc::strcpy(dest as *mut libc::c_char, src.as_ptr());
+        assert_eq!(CStr::from_ptr(dest as *const libc::c_char), src.as_ref());
+        libc::free(dest);
+    }
+}
+
+#[cfg(target_os = "linux")]
+fn test_sigrt() {
+    let min = libc::SIGRTMIN();
+    let max = libc::SIGRTMAX();
+
+    // "The Linux kernel supports a range of 33 different real-time
+    // signals, numbered 32 to 64"
+    assert!(min >= 32);
+    assert!(max >= 32);
+    assert!(min <= 64);
+    assert!(max <= 64);
+
+    // "POSIX.1-2001 requires that an implementation support at least
+    // _POSIX_RTSIG_MAX (8) real-time signals."
+    assert!(min < max);
+    assert!(max - min >= 8)
+}
+
 fn main() {
     test_posix_gettimeofday();
     test_posix_mkstemp();
@@ -315,9 +410,13 @@ fn main() {
     test_isatty();
     test_clocks();
 
+    test_memcpy();
+    test_strcpy();
+
     #[cfg(target_os = "linux")]
     {
         test_posix_fadvise();
         test_sync_file_range();
+        test_sigrt();
     }
 }

src/tools/miri/tests/pass-dep/tokio/tokio_mvp.rs

@@ -1,5 +1,5 @@
 // Need to disable preemption to stay on the supported MVP codepath in mio.
-//@compile-flags: -Zmiri-permissive-provenance
+//@compile-flags: -Zmiri-permissive-provenance -Zmiri-preemption-rate=0
 //@only-target-x86_64-unknown-linux: support for tokio exists only on linux and x86
 
 #[tokio::main]

src/tools/miri/tests/pass/0weak_memory_consistency.rs

@@ -10,7 +10,7 @@
 // the RNG and never observed in our tests.
 //
 // To mitigate this, each test is ran enough times such that the chance
-// of spurious success is very low. These tests never supriously fail.
+// of spurious success is very low. These tests never spuriously fail.
 
 // Test cases and their consistent outcomes are from
 // http://svr-pes20-cppmem.cl.cam.ac.uk/cppmem/

src/tools/miri/tests/pass/dyn-arbitrary-self.rs

@@ -93,7 +93,7 @@ fn pointers_and_wrappers() {
 
     trait Trait {
         // This method isn't object-safe yet. Unsized by-value `self` is object-safe (but not callable
-        // without unsized_locals), but wrappers arond `Self` currently are not.
+        // without unsized_locals), but wrappers around `Self` currently are not.
         // FIXME (mikeyhew) uncomment this when unsized rvalues object-safety is implemented
         // fn wrapper(self: Wrapper<Self>) -> i32;
         fn ptr_wrapper(self: Ptr<Wrapper<Self>>) -> i32;

src/tools/miri/tests/pass/global_allocator.rs

@@ -19,7 +19,7 @@ unsafe impl GlobalAlloc for Allocator {
 
     unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
         if layout.size() == 123 {
-            println!("Dellocated!")
+            println!("Deallocated!")
         }
 
         System.dealloc(ptr, layout)

src/tools/miri/tests/pass/global_allocator.stdout

@@ -1,2 +1,2 @@
 Allocated!
-Dellocated!
+Deallocated!

src/tools/miri/tests/pass/issues/issue-29746.rs

@@ -7,7 +7,7 @@ macro_rules! zip {
     };
 
     // Intermediate steps to build the zipped expression, the match pattern, and
-    //  and the output tuple of the closure, using macro hygene to repeatedly
+    //  and the output tuple of the closure, using macro hygiene to repeatedly
     //  introduce new variables named 'x'.
     ([$a:expr, $($rest:expr),*], $zip:expr, $pat:pat, [$($flat:expr),*]) => {
         zip!([$($rest),*], $zip.zip($a), ($pat,x), [$($flat),*, x])

src/tools/miri/tests/pass/packed_struct.rs

@@ -36,7 +36,7 @@ fn test_basic() {
     let b = x.b;
     assert_eq!(a, 42);
     assert_eq!(b, 99);
-    assert_eq!(&x.fill, &0); // `fill` just requirs 1-byte-align, so this is fine
+    assert_eq!(&x.fill, &0); // `fill` just requires 1-byte-align, so this is fine
     // can't do `assert_eq!(x.a, 42)`, because `assert_eq!` takes a reference
     assert_eq!({ x.a }, 42);
     assert_eq!({ x.b }, 99);

src/tools/miri/tests/pass/ptr_offset.rs

@@ -63,7 +63,7 @@ fn ptr_arith_offset_overflow() {
     let v = [1i16, 2];
     let x = &mut ptr::null(); // going through memory as there are more sanity checks along that path
     *x = v.as_ptr().wrapping_offset(1); // ptr to the 2nd element
-    // Adding 2*isize::max and then 1 is like substracting 1
+    // Adding 2*isize::max and then 1 is like subtracting 1
     *x = x.wrapping_offset(isize::MAX);
     *x = x.wrapping_offset(isize::MAX);
     *x = x.wrapping_offset(1);

src/tools/miri/tests/pass/rfc1623.rs

@@ -58,7 +58,7 @@ fn main() {
     STATIC_SIMPLE_FN(x);
     CONST_SIMPLE_FN(x);
 
-    STATIC_BAZ(BYTES); // neees static lifetime
+    STATIC_BAZ(BYTES); // needs static lifetime
     CONST_BAZ(BYTES);
 
     // make sure this works with different lifetimes

src/tools/miri/tests/pass/shims/fs.rs

@@ -365,7 +365,7 @@ fn test_directory() {
 
     // Deleting the directory should succeed.
     remove_dir(&dir_path).unwrap();
-    // Reading the metadata of a non-existent directory should fail with a "not found" error.
+    // Reading the metadata of a nonexistent directory should fail with a "not found" error.
     assert_eq!(ErrorKind::NotFound, check_metadata(&[], &dir_path).unwrap_err().kind());
 
     // To test remove_dir_all, re-create the directory with a file and a directory in it.

src/tools/miri/tests/pass/stacked-borrows/int-to-ptr.rs

@@ -23,17 +23,17 @@ fn example(variant: bool) {
         let mut c = 42u32;
 
         let x_unique1 = &mut c;
-        // [..., Unique(1)]
+        // stack: [..., Unique(1)]
 
         let x_raw2 = x_unique1 as *mut u32;
         let x_raw2_addr = x_raw2.expose_addr();
-        // [..., Unique(1), SharedRW(2)]
+        // stack: [..., Unique(1), SharedRW(2)]
 
         let x_unique3 = &mut *x_raw2;
-        // [.., Unique(1), SharedRW(2), Unique(3)]
+        // stack: [.., Unique(1), SharedRW(2), Unique(3)]
 
         assert_eq!(not_so_innocent(x_unique3), x_raw2_addr);
-        // [.., Unique(1), SharedRW(2), Unique(3), ..., SharedRW(4)]
+        // stack: [.., Unique(1), SharedRW(2), Unique(3), ..., SharedRW(4)]
 
         // Do an int2ptr cast. This can pick tag 2 or 4 (the two previously exposed tags).
         // 4 is the "obvious" choice (topmost tag, what we used to do with untagged pointers).

src/tools/miri/tests/pass/stacked-borrows/stacked-borrows.rs

@@ -90,7 +90,7 @@ fn mut_raw_mut() {
         assert_eq!(unsafe { *xraw }, 4);
         assert_eq!(*xref1, 4);
         assert_eq!(unsafe { *xraw }, 4);
-        // we cannot use xref2; see `compile-fail/stacked-borows/illegal_read4.rs`
+        // we cannot use xref2; see `compile-fail/stacked-borrows/illegal_read4.rs`
     }
     assert_eq!(x, 4);
 }
@@ -104,7 +104,7 @@ fn partially_invalidate_mut() {
     assert_eq!(*data, (1, 1));
 }
 
-// Make sure that we can handle the situation where a loaction is frozen when being dropped.
+// Make sure that we can handle the situation where a location is frozen when being dropped.
 fn drop_after_sharing() {
     let x = String::from("hello!");
     let _len = x.len();
@@ -224,7 +224,7 @@ fn wide_raw_ptr_in_tuple() {
 fn not_unpin_not_protected() {
     // `&mut !Unpin`, at least for now, does not get `noalias` nor `dereferenceable`, so we also
     // don't add protectors. (We could, but until we have a better idea for where we want to go with
-    // the self-referntial-generator situation, it does not seem worth the potential trouble.)
+    // the self-referential-generator situation, it does not seem worth the potential trouble.)
     use std::marker::PhantomPinned;
 
     pub struct NotUnpin(i32, PhantomPinned);

src/tools/miri/tests/pass/strings.rs

@@ -29,7 +29,7 @@ fn unique_aliasing() {
     // This is a regression test for the aliasing rules of a `Unique<T>` pointer.
     // At the time of writing this test case, Miri does not treat `Unique<T>`
     // pointers as a special case, these are treated like any other raw pointer.
-    // However, there are existing Github issues which may lead to `Unique<T>`
+    // However, there are existing GitHub issues which may lead to `Unique<T>`
     // becoming a special case through asserting unique ownership over the pointee:
     // - https://github.com/rust-lang/unsafe-code-guidelines/issues/258
     // - https://github.com/rust-lang/unsafe-code-guidelines/issues/262

src/tools/miri/tests/pass/tree-borrows/cell-alternate-writes.stderr

@@ -1,10 +1,12 @@
 ──────────────────────────────────────────────────────────────────────
 Warning: this tree is indicative only. Some tags may have been hidden.
 0..  1
+| Act|    └─┬──<TAG=root of the allocation>
 | Re*|      └────<TAG=data, x, y>
 ──────────────────────────────────────────────────────────────────────
 ──────────────────────────────────────────────────────────────────────
 Warning: this tree is indicative only. Some tags may have been hidden.
 0..  1
+| Act|    └─┬──<TAG=root of the allocation>
 | Act|      └────<TAG=data, x, y>
 ──────────────────────────────────────────────────────────────────────

src/tools/miri/tests/pass/tree-borrows/end-of-protector.stderr

@@ -1,12 +1,14 @@
 ──────────────────────────────────────────────────────────────────────
 Warning: this tree is indicative only. Some tags may have been hidden.
 0..  1
+| Act|    └─┬──<TAG=root of the allocation>
 | Res|      └─┬──<TAG=data>
 | Res|        └────<TAG=x>
 ──────────────────────────────────────────────────────────────────────
 ──────────────────────────────────────────────────────────────────────
 Warning: this tree is indicative only. Some tags may have been hidden.
 0..  1
+| Act|    └─┬──<TAG=root of the allocation>
 | Res|      └─┬──<TAG=data>
 | Res|        └─┬──<TAG=x>
 | Res|          └─┬──<TAG=caller:x>
@@ -15,6 +17,7 @@ Warning: this tree is indicative only. Some tags may have been hidden.
 ──────────────────────────────────────────────────────────────────────
 Warning: this tree is indicative only. Some tags may have been hidden.
 0..  1
+| Act|    └─┬──<TAG=root of the allocation>
 | Res|      └─┬──<TAG=data>
 | Res|        ├─┬──<TAG=x>
 | Res|        │ └─┬──<TAG=caller:x>
@@ -24,6 +27,7 @@ Warning: this tree is indicative only. Some tags may have been hidden.
 ──────────────────────────────────────────────────────────────────────
 Warning: this tree is indicative only. Some tags may have been hidden.
 0..  1
+| Act|    └─┬──<TAG=root of the allocation>
 | Act|      └─┬──<TAG=data>
 | Dis|        ├─┬──<TAG=x>
 | Dis|        │ └─┬──<TAG=caller:x>

src/tools/miri/tests/pass/tree-borrows/formatting.stderr

@@ -1,15 +1,17 @@
-─────────────────────────────────────────────────────────────────────────────
+───────────────────────────────────────────────────────────────────────────────────────
 Warning: this tree is indicative only. Some tags may have been hidden.
 0..  1..  2.. 10.. 11..100..101..1000..1001..1024
+| Act| Act| Act| Act| Act| Act|  Act|  Act|  Act|    └─┬──<TAG=root of the allocation>
 | Res| Act| Res| Act| Res| Act|  Res|  Act|  Res|      └─┬──<TAG=data>
 |----| Act|----|?Dis|----|?Dis| ----| ?Dis| ----|        ├────<TAG=data[1]>
 |----|----|----| Act|----|?Dis| ----| ?Dis| ----|        ├────<TAG=data[10]>
 |----|----|----|----|----| Frz| ----| ?Dis| ----|        ├────<TAG=data[100]>
 |----|----|----|----|----|----| ----|  Act| ----|        └────<TAG=data[1000]>
-─────────────────────────────────────────────────────────────────────────────
+───────────────────────────────────────────────────────────────────────────────────────
 ──────────────────────────────────────────────────────────────────────
 Warning: this tree is indicative only. Some tags may have been hidden.
 0..  1
+| Act|    └─┬──<TAG=root of the allocation>
 | Frz|      └─┬──<TAG=x>
 | Frz|        ├─┬──<TAG=xa>
 | Frz|        │ ├────<TAG=xaa>

src/tools/miri/tests/pass/tree-borrows/read-only-from-mut.rs

@@ -1,14 +0,0 @@
-//@compile-flags: -Zmiri-tree-borrows
-
-// Tree Borrows has no issue with several mutable references existing
-// at the same time, as long as they are used only immutably.
-// I.e. multiple Reserved can coexist.
-pub fn main() {
-    unsafe {
-        let base = &mut 42u64;
-        let r1 = &mut *(base as *mut u64);
-        let r2 = &mut *(base as *mut u64);
-        let _l = *r1;
-        let _l = *r2;
-    }
-}

src/tools/miri/tests/pass/tree-borrows/reborrow-is-read.stderr

@@ -1,12 +1,14 @@
 ──────────────────────────────────────────────────────────────────────
 Warning: this tree is indicative only. Some tags may have been hidden.
 0..  1
+| Act|    └─┬──<TAG=root of the allocation>
 | Act|      └─┬──<TAG=parent>
 | Act|        └────<TAG=x>
 ──────────────────────────────────────────────────────────────────────
 ──────────────────────────────────────────────────────────────────────
 Warning: this tree is indicative only. Some tags may have been hidden.
 0..  1
+| Act|    └─┬──<TAG=root of the allocation>
 | Act|      └─┬──<TAG=parent>
 | Frz|        ├────<TAG=x>
 | Res|        └────<TAG=y>

src/tools/miri/tests/pass/tree-borrows/reserved.stderr

@@ -2,6 +2,7 @@
 ──────────────────────────────────────────────────────────────────────
 Warning: this tree is indicative only. Some tags may have been hidden.
 0..  1
+| Act|    └─┬──<TAG=root of the allocation>
 | Re*|      └─┬──<TAG=base>
 | Re*|        ├─┬──<TAG=x>
 | Re*|        │ └─┬──<TAG=caller:x>
@@ -12,6 +13,7 @@ Warning: this tree is indicative only. Some tags may have been hidden.
 ──────────────────────────────────────────────────────────────────────
 Warning: this tree is indicative only. Some tags may have been hidden.
 0..  8
+| Act|    └─┬──<TAG=root of the allocation>
 | Re*|      └─┬──<TAG=base>
 | Re*|        ├────<TAG=x>
 | Re*|        └────<TAG=y>
@@ -20,6 +22,7 @@ Warning: this tree is indicative only. Some tags may have been hidden.
 ──────────────────────────────────────────────────────────────────────
 Warning: this tree is indicative only. Some tags may have been hidden.
 0..  8
+| Act|    └─┬──<TAG=root of the allocation>
 | Act|      └─┬──<TAG=base>
 | Re*|        ├────<TAG=x>
 | Act|        └────<TAG=y>
@@ -28,6 +31,7 @@ Warning: this tree is indicative only. Some tags may have been hidden.
 ──────────────────────────────────────────────────────────────────────
 Warning: this tree is indicative only. Some tags may have been hidden.
 0..  1
+| Act|    └─┬──<TAG=root of the allocation>
 | Res|      └─┬──<TAG=base>
 | Res|        ├─┬──<TAG=x>
 | Res|        │ └─┬──<TAG=caller:x>
@@ -38,6 +42,7 @@ Warning: this tree is indicative only. Some tags may have been hidden.
 ──────────────────────────────────────────────────────────────────────
 Warning: this tree is indicative only. Some tags may have been hidden.
 0..  1
+| Act|    └─┬──<TAG=root of the allocation>
 | Res|      └─┬──<TAG=base>
 | Res|        ├────<TAG=x>
 | Res|        └────<TAG=y>
@@ -46,6 +51,7 @@ Warning: this tree is indicative only. Some tags may have been hidden.
 ──────────────────────────────────────────────────────────────────────
 Warning: this tree is indicative only. Some tags may have been hidden.
 0..  1
+| Act|    └─┬──<TAG=root of the allocation>
 | Act|      └─┬──<TAG=base>
 | Dis|        ├────<TAG=x>
 | Act|        └────<TAG=y>

src/tools/miri/tests/pass/tree-borrows/tree-borrows.rs

@@ -0,0 +1,280 @@
+//@compile-flags: -Zmiri-tree-borrows
+#![feature(allocator_api)]
+
+use std::mem;
+use std::ptr;
+
+fn main() {
+    aliasing_read_only_mutable_refs();
+    string_as_mut_ptr();
+
+    // Stacked Borrows tests
+    read_does_not_invalidate1();
+    read_does_not_invalidate2();
+    mut_raw_then_mut_shr();
+    mut_shr_then_mut_raw();
+    mut_raw_mut();
+    partially_invalidate_mut();
+    drop_after_sharing();
+    direct_mut_to_const_raw();
+    two_raw();
+    shr_and_raw();
+    disjoint_mutable_subborrows();
+    raw_ref_to_part();
+    array_casts();
+    mut_below_shr();
+    wide_raw_ptr_in_tuple();
+    not_unpin_not_protected();
+}
+
+// Tree Borrows has no issue with several mutable references existing
+// at the same time, as long as they are used only immutably.
+// I.e. multiple Reserved can coexist.
+pub fn aliasing_read_only_mutable_refs() {
+    unsafe {
+        let base = &mut 42u64;
+        let r1 = &mut *(base as *mut u64);
+        let r2 = &mut *(base as *mut u64);
+        let _l = *r1;
+        let _l = *r2;
+    }
+}
+
+pub fn string_as_mut_ptr() {
+    // This errors in Stacked Borrows since as_mut_ptr restricts the provenance,
+    // but with Tree Borrows it should work.
+    unsafe {
+        let mut s = String::from("hello");
+        s.reserve(1); // make the `str` that `s` derefs to not cover the entire `s`.
+
+        // Prevent automatically dropping the String's data
+        let mut s = mem::ManuallyDrop::new(s);
+
+        let ptr = s.as_mut_ptr();
+        let len = s.len();
+        let capacity = s.capacity();
+
+        let s = String::from_raw_parts(ptr, len, capacity);
+
+        assert_eq!(String::from("hello"), s);
+    }
+}
+
+// ----- The tests below were taken from Stacked Borrows ----
+
+// Make sure that reading from an `&mut` does, like reborrowing to `&`,
+// NOT invalidate other reborrows.
+fn read_does_not_invalidate1() {
+    fn foo(x: &mut (i32, i32)) -> &i32 {
+        let xraw = x as *mut (i32, i32);
+        let ret = unsafe { &(*xraw).1 };
+        let _val = x.1; // we just read, this does NOT invalidate the reborrows.
+        ret
+    }
+    assert_eq!(*foo(&mut (1, 2)), 2);
+}
+// Same as above, but this time we first create a raw, then read from `&mut`
+// and then freeze from the raw.
+fn read_does_not_invalidate2() {
+    fn foo(x: &mut (i32, i32)) -> &i32 {
+        let xraw = x as *mut (i32, i32);
+        let _val = x.1; // we just read, this does NOT invalidate the raw reborrow.
+        let ret = unsafe { &(*xraw).1 };
+        ret
+    }
+    assert_eq!(*foo(&mut (1, 2)), 2);
+}
+
+// Escape a mut to raw, then share the same mut and use the share, then the raw.
+// That should work.
+fn mut_raw_then_mut_shr() {
+    let mut x = 2;
+    let xref = &mut x;
+    let xraw = &mut *xref as *mut _;
+    let xshr = &*xref;
+    assert_eq!(*xshr, 2);
+    unsafe {
+        *xraw = 4;
+    }
+    assert_eq!(x, 4);
+}
+
+// Create first a shared reference and then a raw pointer from a `&mut`
+// should permit mutation through that raw pointer.
+fn mut_shr_then_mut_raw() {
+    let xref = &mut 2;
+    let _xshr = &*xref;
+    let xraw = xref as *mut _;
+    unsafe {
+        *xraw = 3;
+    }
+    assert_eq!(*xref, 3);
+}
+
+// Ensure that if we derive from a mut a raw, and then from that a mut,
+// and then read through the original mut, that does not invalidate the raw.
+// This shows that the read-exception for `&mut` applies even if the `Shr` item
+// on the stack is not at the top.
+fn mut_raw_mut() {
+    let mut x = 2;
+    {
+        let xref1 = &mut x;
+        let xraw = xref1 as *mut _;
+        let _xref2 = unsafe { &mut *xraw };
+        let _val = *xref1;
+        unsafe {
+            *xraw = 4;
+        }
+        // we can now use both xraw and xref1, for reading
+        assert_eq!(*xref1, 4);
+        assert_eq!(unsafe { *xraw }, 4);
+        assert_eq!(*xref1, 4);
+        assert_eq!(unsafe { *xraw }, 4);
+        // we cannot use xref2; see `compile-fail/stacked-borrows/illegal_read4.rs`
+    }
+    assert_eq!(x, 4);
+}
+
+fn partially_invalidate_mut() {
+    let data = &mut (0u8, 0u8);
+    let reborrow = &mut *data as *mut (u8, u8);
+    let shard = unsafe { &mut (*reborrow).0 };
+    data.1 += 1; // the deref overlaps with `shard`, but that is ok; the access does not overlap.
+    *shard += 1; // so we can still use `shard`.
+    assert_eq!(*data, (1, 1));
+}
+
+// Make sure that we can handle the situation where a location is frozen when being dropped.
+fn drop_after_sharing() {
+    let x = String::from("hello!");
+    let _len = x.len();
+}
+
+// Make sure that coercing &mut T to *const T produces a writeable pointer.
+fn direct_mut_to_const_raw() {
+    // TODO: This is currently disabled, waiting on a decision on <https://github.com/rust-lang/rust/issues/56604>
+    /*let x = &mut 0;
+    let y: *const i32 = x;
+    unsafe { *(y as *mut i32) = 1; }
+    assert_eq!(*x, 1);
+    */
+}
+
+// Make sure that we can create two raw pointers from a mutable reference and use them both.
+fn two_raw() {
+    unsafe {
+        let x = &mut 0;
+        let y1 = x as *mut _;
+        let y2 = x as *mut _;
+        *y1 += 2;
+        *y2 += 1;
+    }
+}
+
+// Make sure that creating a *mut does not invalidate existing shared references.
+fn shr_and_raw() {
+    unsafe {
+        let x = &mut 0;
+        let y1: &i32 = mem::transmute(&*x); // launder lifetimes
+        let y2 = x as *mut _;
+        let _val = *y1;
+        *y2 += 1;
+    }
+}
+
+fn disjoint_mutable_subborrows() {
+    struct Foo {
+        a: String,
+        b: Vec<u32>,
+    }
+
+    unsafe fn borrow_field_a<'a>(this: *mut Foo) -> &'a mut String {
+        &mut (*this).a
+    }
+
+    unsafe fn borrow_field_b<'a>(this: *mut Foo) -> &'a mut Vec<u32> {
+        &mut (*this).b
+    }
+
+    let mut foo = Foo { a: "hello".into(), b: vec![0, 1, 2] };
+
+    let ptr = &mut foo as *mut Foo;
+
+    let a = unsafe { borrow_field_a(ptr) };
+    let b = unsafe { borrow_field_b(ptr) };
+    b.push(4);
+    a.push_str(" world");
+    assert_eq!(format!("{:?} {:?}", a, b), r#""hello world" [0, 1, 2, 4]"#);
+}
+
+fn raw_ref_to_part() {
+    struct Part {
+        _lame: i32,
+    }
+
+    #[repr(C)]
+    struct Whole {
+        part: Part,
+        extra: i32,
+    }
+
+    let it = Box::new(Whole { part: Part { _lame: 0 }, extra: 42 });
+    let whole = ptr::addr_of_mut!(*Box::leak(it));
+    let part = unsafe { ptr::addr_of_mut!((*whole).part) };
+    let typed = unsafe { &mut *(part as *mut Whole) };
+    assert!(typed.extra == 42);
+    drop(unsafe { Box::from_raw(whole) });
+}
+
+/// When casting an array reference to a raw element ptr, that should cover the whole array.
+fn array_casts() {
+    let mut x: [usize; 2] = [0, 0];
+    let p = &mut x as *mut usize;
+    unsafe {
+        *p.add(1) = 1;
+    }
+
+    let x: [usize; 2] = [0, 1];
+    let p = &x as *const usize;
+    assert_eq!(unsafe { *p.add(1) }, 1);
+}
+
+/// Transmuting &&i32 to &&mut i32 is fine.
+fn mut_below_shr() {
+    let x = 0;
+    let y = &x;
+    let p = unsafe { core::mem::transmute::<&&i32, &&mut i32>(&y) };
+    let r = &**p;
+    let _val = *r;
+}
+
+fn wide_raw_ptr_in_tuple() {
+    let mut x: Box<dyn std::any::Any> = Box::new("ouch");
+    let r = &mut *x as *mut dyn std::any::Any;
+    // This triggers the visitor-based recursive retagging. It is *not* supposed to retag raw
+    // pointers, but then the visitor might recurse into the "fields" of a wide raw pointer and
+    // finds a reference (to a vtable) there that it wants to retag... and that would be Wrong.
+    let pair = (r, &0);
+    let r = unsafe { &mut *pair.0 };
+    // Make sure the fn ptr part of the vtable is still fine.
+    r.type_id();
+}
+
+fn not_unpin_not_protected() {
+    // `&mut !Unpin`, at least for now, does not get `noalias` nor `dereferenceable`, so we also
+    // don't add protectors. (We could, but until we have a better idea for where we want to go with
+    // the self-referential-generator situation, it does not seem worth the potential trouble.)
+    use std::marker::PhantomPinned;
+
+    pub struct NotUnpin(i32, PhantomPinned);
+
+    fn inner(x: &mut NotUnpin, f: fn(&mut NotUnpin)) {
+        // `f` may mutate, but it may not deallocate!
+        f(x)
+    }
+
+    inner(Box::leak(Box::new(NotUnpin(0, PhantomPinned))), |x| {
+        let raw = x as *mut _;
+        drop(unsafe { Box::from_raw(raw) });
+    });
+}

src/tools/miri/tests/pass/weak_memory/extra_cpp.rs

@@ -1,6 +1,6 @@
 //@compile-flags: -Zmiri-ignore-leaks
 
-// Tests operations not perfomable through C++'s atomic API
+// Tests operations not performable through C++'s atomic API
 // but doable in safe (at least sound) Rust.
 
 #![feature(atomic_from_mut)]

src/tools/miri/tests/pass/weak_memory/extra_cpp_unsafe.rs

@@ -1,6 +1,6 @@
 //@compile-flags: -Zmiri-ignore-leaks
 
-// Tests operations not perfomable through C++'s atomic API
+// Tests operations not performable through C++'s atomic API
 // but doable in unsafe Rust which we think *should* be fine.
 // Nonetheless they may be determined as inconsistent with the
 // memory model in the future.