Auto merge of #2071 - RalfJung:provenance, r=RalfJung

adjust for provenance cleanup This is the Miri side of rust-lang/rust#96165
rust-lang · Apr 20, 2022 · c9039de · c9039de
2 parents 598ae74 + b5a76c7
commit c9039de
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Showing 9 changed files with 92 additions and 49 deletions.
diff --git a/rust-version b/rust-version
@@ -1 +1 @@
-c8422403f775126c40d558838d321c063554c822
+27af5175497936ea3413bef5816e7c0172514b9c
diff --git a/src/data_race.rs b/src/data_race.rs
@@ -999,15 +999,15 @@ trait EvalContextPrivExt<'mir, 'tcx: 'mir>: MiriEvalContextExt<'mir, 'tcx> {
         if let Some(data_race) = &this.machine.data_race {
             if data_race.multi_threaded.get() {
                 let size = place.layout.size;
-                let (alloc_id, base_offset, ptr) = this.ptr_get_alloc_id(place.ptr)?;
+                let (alloc_id, base_offset, _tag) = this.ptr_get_alloc_id(place.ptr)?;
                 // Load and log the atomic operation.
                 // Note that atomic loads are possible even from read-only allocations, so `get_alloc_extra_mut` is not an option.
                 let alloc_meta = &this.get_alloc_extra(alloc_id)?.data_race.as_ref().unwrap();
                 log::trace!(
                     "Atomic op({}) with ordering {:?} on {:?} (size={})",
                     description,
                     &atomic,
-                    ptr,
+                    place.ptr,
                     size.bytes()
                 );
 
@@ -1039,7 +1039,7 @@ trait EvalContextPrivExt<'mir, 'tcx: 'mir>: MiriEvalContextExt<'mir, 'tcx> {
                     {
                         log::trace!(
                             "Updated atomic memory({:?}, size={}) to {:#?}",
-                            ptr,
+                            place.ptr,
                             size.bytes(),
                             range.atomic_ops
                         );

diff --git a/src/helpers.rs b/src/helpers.rs
@@ -271,8 +271,6 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     /// Visits the memory covered by `place`, sensitive to freezing: the 2nd parameter
     /// of `action` will be true if this is frozen, false if this is in an `UnsafeCell`.
     /// The range is relative to `place`.
-    ///
-    /// Assumes that the `place` has a proper pointer in it.
     fn visit_freeze_sensitive(
         &self,
         place: &MPlaceTy<'tcx, Tag>,
@@ -290,33 +288,30 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         // Store how far we proceeded into the place so far. Everything to the left of
         // this offset has already been handled, in the sense that the frozen parts
         // have had `action` called on them.
-        let ptr = place.ptr.into_pointer_or_addr().unwrap();
-        let start_offset = ptr.into_parts().1 as Size; // we just compare offsets, the abs. value never matters
-        let mut cur_offset = start_offset;
+        let start_addr = place.ptr.addr();
+        let mut cur_addr = start_addr;
         // Called when we detected an `UnsafeCell` at the given offset and size.
         // Calls `action` and advances `cur_ptr`.
-        let mut unsafe_cell_action = |unsafe_cell_ptr: Pointer<Option<Tag>>,
+        let mut unsafe_cell_action = |unsafe_cell_ptr: &Pointer<Option<Tag>>,
                                       unsafe_cell_size: Size| {
-            let unsafe_cell_ptr = unsafe_cell_ptr.into_pointer_or_addr().unwrap();
-            debug_assert_eq!(unsafe_cell_ptr.provenance, ptr.provenance);
             // We assume that we are given the fields in increasing offset order,
             // and nothing else changes.
-            let unsafe_cell_offset = unsafe_cell_ptr.into_parts().1 as Size; // we just compare offsets, the abs. value never matters
-            assert!(unsafe_cell_offset >= cur_offset);
-            let frozen_size = unsafe_cell_offset - cur_offset;
+            let unsafe_cell_addr = unsafe_cell_ptr.addr();
+            assert!(unsafe_cell_addr >= cur_addr);
+            let frozen_size = unsafe_cell_addr - cur_addr;
             // Everything between the cur_ptr and this `UnsafeCell` is frozen.
             if frozen_size != Size::ZERO {
-                action(alloc_range(cur_offset - start_offset, frozen_size), /*frozen*/ true)?;
+                action(alloc_range(cur_addr - start_addr, frozen_size), /*frozen*/ true)?;
             }
-            cur_offset += frozen_size;
+            cur_addr += frozen_size;
             // This `UnsafeCell` is NOT frozen.
             if unsafe_cell_size != Size::ZERO {
                 action(
-                    alloc_range(cur_offset - start_offset, unsafe_cell_size),
+                    alloc_range(cur_addr - start_addr, unsafe_cell_size),
                     /*frozen*/ false,
                 )?;
             }
-            cur_offset += unsafe_cell_size;
+            cur_addr += unsafe_cell_size;
             // Done
             Ok(())
         };
@@ -334,7 +329,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                         .unwrap_or_else(|| place.layout.size);
                     // Now handle this `UnsafeCell`, unless it is empty.
                     if unsafe_cell_size != Size::ZERO {
-                        unsafe_cell_action(place.ptr, unsafe_cell_size)
+                        unsafe_cell_action(&place.ptr, unsafe_cell_size)
                     } else {
                         Ok(())
                     }
@@ -344,7 +339,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         }
         // The part between the end_ptr and the end of the place is also frozen.
         // So pretend there is a 0-sized `UnsafeCell` at the end.
-        unsafe_cell_action(place.ptr.wrapping_offset(size, this), Size::ZERO)?;
+        unsafe_cell_action(&place.ptr.offset(size, this)?, Size::ZERO)?;
         // Done!
         return Ok(());
 
@@ -428,9 +423,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                         let mut places =
                             fields.collect::<InterpResult<'tcx, Vec<MPlaceTy<'tcx, Tag>>>>()?;
                         // we just compare offsets, the abs. value never matters
-                        places.sort_by_key(|place| {
-                            place.ptr.into_pointer_or_addr().unwrap().into_parts().1 as Size
-                        });
+                        places.sort_by_key(|place| place.ptr.addr());
                         self.walk_aggregate(place, places.into_iter().map(Ok))
                     }
                     FieldsShape::Union { .. } | FieldsShape::Primitive => {
@@ -777,6 +770,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     /// Mark a machine allocation that was just created as immutable.
     fn mark_immutable(&mut self, mplace: &MemPlace<Tag>) {
         let this = self.eval_context_mut();
+        // This got just allocated, so there definitely is a pointer here.
         this.alloc_mark_immutable(mplace.ptr.into_pointer_or_addr().unwrap().provenance.alloc_id)
             .unwrap();
     }

diff --git a/src/intptrcast.rs b/src/intptrcast.rs
@@ -128,7 +128,7 @@ impl<'mir, 'tcx> GlobalStateInner {
 
     /// Convert a relative (tcx) pointer to an absolute address.
     pub fn rel_ptr_to_addr(ecx: &MiriEvalContext<'mir, 'tcx>, ptr: Pointer<AllocId>) -> u64 {
-        let (alloc_id, offset) = ptr.into_parts(); // offset is relative
+        let (alloc_id, offset) = ptr.into_parts(); // offset is relative (AllocId provenance)
         let base_addr = GlobalStateInner::alloc_base_addr(ecx, alloc_id);
 
         // Add offset with the right kind of pointer-overflowing arithmetic.
@@ -137,7 +137,7 @@ impl<'mir, 'tcx> GlobalStateInner {
     }
 
     pub fn abs_ptr_to_rel(ecx: &MiriEvalContext<'mir, 'tcx>, ptr: Pointer<Tag>) -> Size {
-        let (tag, addr) = ptr.into_parts(); // addr is absolute
+        let (tag, addr) = ptr.into_parts(); // addr is absolute (Tag provenance)
         let base_addr = GlobalStateInner::alloc_base_addr(ecx, tag.alloc_id);
 
         // Wrapping "addr - base_addr"

diff --git a/src/machine.rs b/src/machine.rs
@@ -360,6 +360,7 @@ impl<'mir, 'tcx> Evaluator<'mir, 'tcx> {
         name: &str,
         ptr: Pointer<Option<Tag>>,
     ) {
+        // This got just allocated, so there definitely is a pointer here.
         let ptr = ptr.into_pointer_or_addr().unwrap();
         this.machine.extern_statics.try_insert(Symbol::intern(name), ptr).unwrap();
     }
@@ -431,11 +432,13 @@ impl<'mir, 'tcx> MiriEvalContextExt<'mir, 'tcx> for MiriEvalContext<'mir, 'tcx>
 /// Machine hook implementations.
 impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'mir, 'tcx> {
     type MemoryKind = MiriMemoryKind;
+    type ExtraFnVal = Dlsym;
 
     type FrameExtra = FrameData<'tcx>;
     type AllocExtra = AllocExtra;
+
     type PointerTag = Tag;
-    type ExtraFnVal = Dlsym;
+    type TagExtra = SbTag;
 
     type MemoryMap =
         MonoHashMap<AllocId, (MemoryKind<MiriMemoryKind>, Allocation<Tag, Self::AllocExtra>)>;
@@ -607,26 +610,26 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'mir, 'tcx> {
     fn ptr_get_alloc(
         ecx: &MiriEvalContext<'mir, 'tcx>,
         ptr: Pointer<Self::PointerTag>,
-    ) -> (AllocId, Size) {
+    ) -> (AllocId, Size, Self::TagExtra) {
         let rel = intptrcast::GlobalStateInner::abs_ptr_to_rel(ecx, ptr);
-        (ptr.provenance.alloc_id, rel)
+        (ptr.provenance.alloc_id, rel, ptr.provenance.sb)
     }
 
     #[inline(always)]
     fn memory_read(
         _tcx: TyCtxt<'tcx>,
         machine: &Self,
         alloc_extra: &AllocExtra,
-        tag: Tag,
+        (alloc_id, tag): (AllocId, Self::TagExtra),
         range: AllocRange,
     ) -> InterpResult<'tcx> {
         if let Some(data_race) = &alloc_extra.data_race {
-            data_race.read(tag.alloc_id, range, machine.data_race.as_ref().unwrap())?;
+            data_race.read(alloc_id, range, machine.data_race.as_ref().unwrap())?;
         }
         if let Some(stacked_borrows) = &alloc_extra.stacked_borrows {
             stacked_borrows.memory_read(
-                tag.alloc_id,
-                tag.sb,
+                alloc_id,
+                tag,
                 range,
                 machine.stacked_borrows.as_ref().unwrap(),
             )
@@ -640,16 +643,16 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'mir, 'tcx> {
         _tcx: TyCtxt<'tcx>,
         machine: &mut Self,
         alloc_extra: &mut AllocExtra,
-        tag: Tag,
+        (alloc_id, tag): (AllocId, Self::TagExtra),
         range: AllocRange,
     ) -> InterpResult<'tcx> {
         if let Some(data_race) = &mut alloc_extra.data_race {
-            data_race.write(tag.alloc_id, range, machine.data_race.as_mut().unwrap())?;
+            data_race.write(alloc_id, range, machine.data_race.as_mut().unwrap())?;
         }
         if let Some(stacked_borrows) = &mut alloc_extra.stacked_borrows {
             stacked_borrows.memory_written(
-                tag.alloc_id,
-                tag.sb,
+                alloc_id,
+                tag,
                 range,
                 machine.stacked_borrows.as_mut().unwrap(),
             )
@@ -663,19 +666,19 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'mir, 'tcx> {
         _tcx: TyCtxt<'tcx>,
         machine: &mut Self,
         alloc_extra: &mut AllocExtra,
-        tag: Tag,
+        (alloc_id, tag): (AllocId, Self::TagExtra),
         range: AllocRange,
     ) -> InterpResult<'tcx> {
-        if Some(tag.alloc_id) == machine.tracked_alloc_id {
-            register_diagnostic(NonHaltingDiagnostic::FreedAlloc(tag.alloc_id));
+        if Some(alloc_id) == machine.tracked_alloc_id {
+            register_diagnostic(NonHaltingDiagnostic::FreedAlloc(alloc_id));
         }
         if let Some(data_race) = &mut alloc_extra.data_race {
-            data_race.deallocate(tag.alloc_id, range, machine.data_race.as_mut().unwrap())?;
+            data_race.deallocate(alloc_id, range, machine.data_race.as_mut().unwrap())?;
         }
         if let Some(stacked_borrows) = &mut alloc_extra.stacked_borrows {
             stacked_borrows.memory_deallocated(
-                tag.alloc_id,
-                tag.sb,
+                alloc_id,
+                tag,
                 range,
                 machine.stacked_borrows.as_mut().unwrap(),
             )

diff --git a/src/shims/backtrace.rs b/src/shims/backtrace.rs
@@ -124,7 +124,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
 
         let ptr = this.read_pointer(ptr)?;
         // Take apart the pointer, we need its pieces.
-        let (alloc_id, offset, ptr) = this.ptr_get_alloc_id(ptr)?;
+        let (alloc_id, offset, _tag) = this.ptr_get_alloc_id(ptr)?;
 
         let fn_instance =
             if let Some(GlobalAlloc::Function(instance)) = this.tcx.get_global_alloc(alloc_id) {

diff --git a/src/shims/mod.rs b/src/shims/mod.rs
@@ -83,10 +83,9 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         }
 
         let ptr = this.read_pointer(ptr_op)?;
-        if let Ok(ptr) = ptr.into_pointer_or_addr() {
+        if let Ok((alloc_id, _offset, _)) = this.ptr_try_get_alloc_id(ptr) {
             // Only do anything if we can identify the allocation this goes to.
-            let (_, cur_align) =
-                this.get_alloc_size_and_align(ptr.provenance.alloc_id, AllocCheck::MaybeDead)?;
+            let (_, cur_align) = this.get_alloc_size_and_align(alloc_id, AllocCheck::MaybeDead)?;
             if cur_align.bytes() >= req_align {
                 // If the allocation alignment is at least the required alignment we use the
                 // real implementation.

diff --git a/src/stacked_borrows.rs b/src/stacked_borrows.rs
@@ -702,8 +702,7 @@ trait EvalContextPrivExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             );
             return Ok(());
         }
-        let (alloc_id, base_offset, ptr) = this.ptr_get_alloc_id(place.ptr)?;
-        let orig_tag = ptr.provenance.sb;
+        let (alloc_id, base_offset, orig_tag) = this.ptr_get_alloc_id(place.ptr)?;
 
         // Ensure we bail out if the pointer goes out-of-bounds (see miri#1050).
         let (alloc_size, _) =

diff --git a/tests/run-pass/issue-miri-2068.rs b/tests/run-pass/issue-miri-2068.rs
@@ -0,0 +1,48 @@
+#![feature(pin_macro)]
+
+use core::future::Future;
+use core::pin::Pin;
+use core::task::{Context, Poll};
+
+use std::sync::Arc;
+
+struct NopWaker;
+
+impl std::task::Wake for NopWaker {
+    fn wake(self: Arc<Self>) {}
+}
+
+pub fn fuzzing_block_on<O, F: Future<Output = O>>(fut: F) -> O {
+    let mut fut = std::pin::pin!(fut);
+    let waker = std::task::Waker::from(Arc::new(NopWaker));
+    let mut context = std::task::Context::from_waker(&waker);
+    loop {
+        match fut.as_mut().poll(&mut context) {
+            Poll::Ready(v) => return v,
+            Poll::Pending => {}
+        }
+    }
+}
+
+pub struct LastFuture<S> {
+    last: S,
+}
+
+impl<S> Future for LastFuture<S>
+where
+    Self: Unpin,
+    S: Unpin + Copy,
+{
+    type Output = S;
+
+    fn poll(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Self::Output> {
+        return Poll::Ready(self.last);
+    }
+}
+
+fn main() {
+    fuzzing_block_on(async {
+        LastFuture { last: &0u32 }.await;
+        LastFuture { last: Option::<u32>::None }.await;
+    });
+}