Auto merge of rust-lang#106121 - RalfJung:miri, r=RalfJung

update Miri

Noteworthy PRs:
- rust-lang/miri#2357
- rust-lang/miri#2646
- rust-lang/miri#2718
- rust-lang/miri#2721
- rust-lang/miri#2725

CONTRIBUTING.md

@@ -232,16 +232,16 @@ You can also directly run Miri on a Rust source file:
 
 ## Advanced topic: Syncing with the rustc repo
 
-We use the [`josh` proxy](https://github.com/josh-project/josh) to transmit
-changes between the rustc and Miri repositories. For now, the latest git version
-of josh needs to be built from source. This downloads and runs josh:
+We use the [`josh` proxy](https://github.com/josh-project/josh) to transmit changes between the
+rustc and Miri repositories.
 
 ```sh
-git clone https://github.com/josh-project/josh
-cd josh
-cargo run --release -p josh-proxy -- --local=local --remote=https://github.com --no-background
+cargo +stable install josh-proxy --git https://github.com/josh-project/josh --tag r22.12.06
+josh-proxy --local=$HOME/.cache/josh --remote=https://github.com --no-background
 ```
 
+This uses a directory `$HOME/.cache/josh` as a cache, to speed up repeated pulling/pushing.
+
 ### Importing changes from the rustc repo
 
 Josh needs to be running, as described above.

README.md

@@ -399,6 +399,8 @@ to Miri failing to detect cases of undefined behavior in a program.
 * `-Zmiri-track-weak-memory-loads` shows a backtrace when weak memory emulation returns an outdated
   value from a load. This can help diagnose problems that disappear under
   `-Zmiri-disable-weak-memory-emulation`.
+* `-Zmiri-force-page-size=<num>` overrides the default page size for an architecture, in multiples of 1k.
+  `4` is default for most targets. This value should always be a power of 2 and nonzero.
 
 [function ABI]: https://doc.rust-lang.org/reference/items/functions.html#extern-function-qualifier
 
@@ -574,6 +576,21 @@ extern "Rust" {
 
     /// Miri-provided extern function to deallocate memory.
     fn miri_dealloc(ptr: *mut u8, size: usize, align: usize);
+
+    /// Convert a path from the host Miri runs on to the target Miri interprets.
+    /// Performs conversion of path separators as needed.
+    ///
+    /// Usually Miri performs this kind of conversion automatically. However, manual conversion
+    /// might be necessary when reading an environment variable that was set on the host
+    /// (such as TMPDIR) and using it as a target path.
+    ///
+    /// Only works with isolation disabled.
+    ///
+    /// `in` must point to a null-terminated string, and will be read as the input host path.
+    /// `out` must point to at least `out_size` many bytes, and the result will be stored there
+    /// with a null terminator.
+    /// Returns 0 if the `out` buffer was large enough, and the required size otherwise.
+    fn miri_host_to_target_path(path: *const i8, out: *mut i8, out_size: usize) -> usize;
 }
 ```
 

miri

@@ -243,7 +243,7 @@ if [ -z "$CARGO_PROFILE_DEV_OPT_LEVEL" ]; then
     export CARGO_PROFILE_DEV_OPT_LEVEL=2
 fi
 # Enable rustc-specific lints (ignored without `-Zunstable-options`).
-export RUSTFLAGS="-Zunstable-options -Wrustc::internal $RUSTFLAGS"
+export RUSTFLAGS="-Zunstable-options -Wrustc::internal -Wrust_2018_idioms -Wunused_lifetimes -Wsemicolon_in_expressions_from_macros $RUSTFLAGS"
 # We set the rpath so that Miri finds the private rustc libraries it needs.
 export RUSTFLAGS="-C link-args=-Wl,-rpath,$LIBDIR $RUSTFLAGS"
 

rust-version

@@ -1 +1 @@
-203c8765ea33c65d888febe0e8219c4bb11b0d89
+4f4d0586ad20c66a16d547581ca379beafece93a

src/bin/miri.rs

@@ -512,6 +512,18 @@ fn main() {
             };
 
             miri_config.num_cpus = num_cpus;
+        } else if let Some(param) = arg.strip_prefix("-Zmiri-force-page-size=") {
+            let page_size = match param.parse::<u64>() {
+                Ok(i) =>
+                    if i.is_power_of_two() {
+                        i * 1024
+                    } else {
+                        show_error!("-Zmiri-force-page-size requires a power of 2: {}", i)
+                    },
+                Err(err) => show_error!("-Zmiri-force-page-size requires a `u64`: {}", err),
+            };
+
+            miri_config.page_size = Some(page_size);
         } else {
             // Forward to rustc.
             rustc_args.push(arg);

src/borrow_tracker/mod.rs

@@ -264,15 +264,23 @@ impl GlobalStateInner {
 
 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
-    fn retag_ptr_value(&mut self, kind: RetagKind, val: &ImmTy<'tcx, Provenance>) -> InterpResult<'tcx, ImmTy<'tcx, Provenance>> {
+    fn retag_ptr_value(
+        &mut self,
+        kind: RetagKind,
+        val: &ImmTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx, ImmTy<'tcx, Provenance>> {
         let this = self.eval_context_mut();
         let method = this.machine.borrow_tracker.as_ref().unwrap().borrow().borrow_tracker_method;
         match method {
             BorrowTrackerMethod::StackedBorrows => this.sb_retag_ptr_value(kind, val),
         }
     }
 
-    fn retag_place_contents(&mut self, kind: RetagKind, place: &PlaceTy<'tcx, Provenance>) -> InterpResult<'tcx> {
+    fn retag_place_contents(
+        &mut self,
+        kind: RetagKind,
+        place: &PlaceTy<'tcx, Provenance>,
+    ) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
         let method = this.machine.borrow_tracker.as_ref().unwrap().borrow().borrow_tracker_method;
         match method {

src/borrow_tracker/stacked_borrows/diagnostics.rs

@@ -462,7 +462,9 @@ impl<'history, 'ecx, 'mir, 'tcx> DiagnosticCx<'history, 'ecx, 'mir, 'tcx> {
             Operation::Retag(RetagOp { orig_tag, permission, new_tag, .. }) => {
                 let permission = permission
                     .expect("start_grant should set the current permission before popping a tag");
-                format!(" due to {permission:?} retag from {orig_tag:?} (that retag created {new_tag:?})")
+                format!(
+                    " due to {permission:?} retag from {orig_tag:?} (that retag created {new_tag:?})"
+                )
             }
         };
 

src/borrow_tracker/stacked_borrows/mod.rs

@@ -14,6 +14,7 @@ use rustc_middle::mir::{Mutability, RetagKind};
 use rustc_middle::ty::{
     self,
     layout::{HasParamEnv, LayoutOf},
+    Ty,
 };
 use rustc_target::abi::{Abi, Size};
 
@@ -64,7 +65,7 @@ impl NewPermission {
     /// A key function: determine the permissions to grant at a retag for the given kind of
     /// reference/pointer.
     fn from_ref_ty<'tcx>(
-        ty: ty::Ty<'tcx>,
+        ty: Ty<'tcx>,
         kind: RetagKind,
         cx: &crate::MiriInterpCx<'_, 'tcx>,
     ) -> Self {
@@ -864,7 +865,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
             RetagKind::FnEntry => unreachable!(),
             RetagKind::Raw | RetagKind::Default => RetagCause::Normal,
         };
-        this.sb_retag_reference(&val, new_perm, retag_cause)
+        this.sb_retag_reference(val, new_perm, retag_cause)
     }
 
     fn sb_retag_place_contents(