Auto merge of #1804 - RalfJung:ptrless-allocs, r=RalfJung

update for Memory API changes The Miri side of rust-lang/rust#85376.
rust-lang · May 19, 2021 · b0e5d5f · b0e5d5f
2 parents cda0b07 + aba96b8
commit b0e5d5f
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Showing 12 changed files with 117 additions and 97 deletions.
diff --git a/rust-version b/rust-version
@@ -1 +1 @@
-3e99439f4dacc8ba0d2ca48d221694362d587927
+3e827cc21e0734edd26170e8d1481f0d66a1426b
diff --git a/src/data_race.rs b/src/data_race.rs
@@ -720,7 +720,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: MiriEvalContextExt<'mir, 'tcx> {
         if let Some(data_race) = &mut this.memory.extra.data_race {
             if data_race.multi_threaded.get() {
                 let alloc_meta =
-                    this.memory.get_raw_mut(ptr.alloc_id)?.extra.data_race.as_mut().unwrap();
+                    this.memory.get_alloc_extra_mut(ptr.alloc_id)?.data_race.as_mut().unwrap();
                 alloc_meta.reset_clocks(ptr.offset, size);
             }
         }
@@ -1024,7 +1024,7 @@ trait EvalContextPrivExt<'mir, 'tcx: 'mir>: MiriEvalContextExt<'mir, 'tcx> {
                 let place_ptr = place.ptr.assert_ptr();
                 let size = place.layout.size;
                 let alloc_meta =
-                    &this.memory.get_raw(place_ptr.alloc_id)?.extra.data_race.as_ref().unwrap();
+                    &this.memory.get_alloc_extra(place_ptr.alloc_id)?.data_race.as_ref().unwrap();
                 log::trace!(
                     "Atomic op({}) with ordering {:?} on memory({:?}, offset={}, size={})",
                     description,

diff --git a/src/diagnostics.rs b/src/diagnostics.rs
@@ -136,13 +136,13 @@ pub fn report_error<'tcx, 'mir>(
 
     // Extra output to help debug specific issues.
     match e.kind() {
-        UndefinedBehavior(UndefinedBehaviorInfo::InvalidUninitBytes(Some(access))) => {
+        UndefinedBehavior(UndefinedBehaviorInfo::InvalidUninitBytes(Some((alloc_id, access)))) => {
             eprintln!(
                 "Uninitialized read occurred at offsets 0x{:x}..0x{:x} into this allocation:",
-                access.uninit_ptr.offset.bytes(),
-                access.uninit_ptr.offset.bytes() + access.uninit_size.bytes(),
+                access.uninit_offset.bytes(),
+                access.uninit_offset.bytes() + access.uninit_size.bytes(),
             );
-            eprintln!("{:?}", ecx.memory.dump_alloc(access.uninit_ptr.alloc_id));
+            eprintln!("{:?}", ecx.memory.dump_alloc(*alloc_id));
         }
         _ => {}
     }

diff --git a/src/helpers.rs b/src/helpers.rs
@@ -8,7 +8,7 @@ use log::trace;
 use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX};
 use rustc_middle::mir;
 use rustc_middle::ty::{self, layout::TyAndLayout, List, TyCtxt};
-use rustc_target::abi::{FieldsShape, LayoutOf, Size, Variants};
+use rustc_target::abi::{Align, FieldsShape, LayoutOf, Size, Variants};
 use rustc_target::spec::abi::Abi;
 
 use rand::RngCore;
@@ -577,10 +577,12 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         let ptr = this.force_ptr(sptr)?; // We need to read at least 1 byte, so we can eagerly get a ptr.
 
         // Step 1: determine the length.
-        let alloc = this.memory.get_raw(ptr.alloc_id)?;
         let mut len = Size::ZERO;
         loop {
-            let byte = alloc.read_scalar(this, ptr.offset(len, this)?, size1)?.to_u8()?;
+            // FIXME: We are re-getting the allocation each time around the loop.
+            // Would be nice if we could somehow "extend" an existing AllocRange.
+            let alloc = this.memory.get(ptr.offset(len, this)?.into(), size1, Align::ONE)?.unwrap(); // not a ZST, so we will get a result
+            let byte = alloc.read_scalar(alloc_range(Size::ZERO, size1))?.to_u8()?;
             if byte == 0 {
                 break;
             } else {
@@ -595,12 +597,15 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     fn read_wide_str(&self, sptr: Scalar<Tag>) -> InterpResult<'tcx, Vec<u16>> {
         let this = self.eval_context_ref();
         let size2 = Size::from_bytes(2);
+        let align2 = Align::from_bytes(2).unwrap();
 
         let mut ptr = this.force_ptr(sptr)?; // We need to read at least 1 wchar, so we can eagerly get a ptr.
         let mut wchars = Vec::new();
-        let alloc = this.memory.get_raw(ptr.alloc_id)?;
         loop {
-            let wchar = alloc.read_scalar(this, ptr, size2)?.to_u16()?;
+            // FIXME: We are re-getting the allocation each time around the loop.
+            // Would be nice if we could somehow "extend" an existing AllocRange.
+            let alloc = this.memory.get(ptr.into(), size2, align2)?.unwrap(); // not a ZST, so we will get a result
+            let wchar = alloc.read_scalar(alloc_range(Size::ZERO, size2))?.to_u16()?;
             if wchar == 0 {
                 break;
             } else {

diff --git a/src/machine.rs b/src/machine.rs
@@ -506,15 +506,57 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'mir, 'tcx> {
     }
 
     #[inline(always)]
-    fn before_deallocation(
-        memory_extra: &mut Self::MemoryExtra,
-        id: AllocId,
+    fn memory_read(
+        _memory_extra: &Self::MemoryExtra,
+        alloc: &Allocation<Tag, AllocExtra>,
+        ptr: Pointer<Tag>,
+        size: Size,
     ) -> InterpResult<'tcx> {
-        if Some(id) == memory_extra.tracked_alloc_id {
-            register_diagnostic(NonHaltingDiagnostic::FreedAlloc(id));
+        if let Some(data_race) = &alloc.extra.data_race {
+            data_race.read(ptr, size)?;
         }
+        if let Some(stacked_borrows) = &alloc.extra.stacked_borrows {
+            stacked_borrows.memory_read(ptr, size)
+        } else {
+            Ok(())
+        }
+    }
 
-        Ok(())
+    #[inline(always)]
+    fn memory_written(
+        _memory_extra: &mut Self::MemoryExtra,
+        alloc: &mut Allocation<Tag, AllocExtra>,
+        ptr: Pointer<Tag>,
+        size: Size,
+    ) -> InterpResult<'tcx> {
+        if let Some(data_race) = &mut alloc.extra.data_race {
+            data_race.write(ptr, size)?;
+        }
+        if let Some(stacked_borrows) = &mut alloc.extra.stacked_borrows {
+            stacked_borrows.memory_written(ptr, size)
+        } else {
+            Ok(())
+        }
+    }
+
+    #[inline(always)]
+    fn memory_deallocated(
+        memory_extra: &mut Self::MemoryExtra,
+        alloc: &mut Allocation<Tag, AllocExtra>,
+        ptr: Pointer<Tag>,
+    ) -> InterpResult<'tcx> {
+        let size = alloc.size();
+        if Some(ptr.alloc_id) == memory_extra.tracked_alloc_id {
+            register_diagnostic(NonHaltingDiagnostic::FreedAlloc(ptr.alloc_id));
+        }
+        if let Some(data_race) = &mut alloc.extra.data_race {
+            data_race.deallocate(ptr, size)?;
+        }
+        if let Some(stacked_borrows) = &mut alloc.extra.stacked_borrows {
+            stacked_borrows.memory_deallocated(ptr, size)
+        } else {
+            Ok(())
+        }
     }
 
     fn after_static_mem_initialized(
@@ -601,53 +643,3 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'mir, 'tcx> {
         intptrcast::GlobalState::ptr_to_int(ptr, memory)
     }
 }
-
-impl AllocationExtra<Tag> for AllocExtra {
-    #[inline(always)]
-    fn memory_read<'tcx>(
-        alloc: &Allocation<Tag, AllocExtra>,
-        ptr: Pointer<Tag>,
-        size: Size,
-    ) -> InterpResult<'tcx> {
-        if let Some(data_race) = &alloc.extra.data_race {
-            data_race.read(ptr, size)?;
-        }
-        if let Some(stacked_borrows) = &alloc.extra.stacked_borrows {
-            stacked_borrows.memory_read(ptr, size)
-        } else {
-            Ok(())
-        }
-    }
-
-    #[inline(always)]
-    fn memory_written<'tcx>(
-        alloc: &mut Allocation<Tag, AllocExtra>,
-        ptr: Pointer<Tag>,
-        size: Size,
-    ) -> InterpResult<'tcx> {
-        if let Some(data_race) = &mut alloc.extra.data_race {
-            data_race.write(ptr, size)?;
-        }
-        if let Some(stacked_borrows) = &mut alloc.extra.stacked_borrows {
-            stacked_borrows.memory_written(ptr, size)
-        } else {
-            Ok(())
-        }
-    }
-
-    #[inline(always)]
-    fn memory_deallocated<'tcx>(
-        alloc: &mut Allocation<Tag, AllocExtra>,
-        ptr: Pointer<Tag>,
-        size: Size,
-    ) -> InterpResult<'tcx> {
-        if let Some(data_race) = &mut alloc.extra.data_race {
-            data_race.deallocate(ptr, size)?;
-        }
-        if let Some(stacked_borrows) = &mut alloc.extra.stacked_borrows {
-            stacked_borrows.memory_deallocated(ptr, size)
-        } else {
-            Ok(())
-        }
-    }
-}
diff --git a/src/shims/intrinsics.rs b/src/shims/intrinsics.rs
@@ -574,7 +574,13 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
         // be 8-aligned).
         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
-        this.memory.check_ptr_access(place.ptr, place.layout.size, align)?;
+        this.memory.check_ptr_access_align(
+            place.ptr,
+            place.layout.size,
+            align,
+            CheckInAllocMsg::MemoryAccessTest,
+        )?;
+        // Perform regular access.
         this.write_scalar(val, dest)?;
         Ok(())
     }
@@ -594,7 +600,12 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
         // be 8-aligned).
         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
-        this.memory.check_ptr_access(place.ptr, place.layout.size, align)?;
+        this.memory.check_ptr_access_align(
+            place.ptr,
+            place.layout.size,
+            align,
+            CheckInAllocMsg::MemoryAccessTest,
+        )?;
 
         // Perform atomic store
         this.write_scalar_atomic(val, &place, atomic)?;
@@ -644,7 +655,12 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
         // be 8-aligned).
         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
-        this.memory.check_ptr_access(place.ptr, place.layout.size, align)?;
+        this.memory.check_ptr_access_align(
+            place.ptr,
+            place.layout.size,
+            align,
+            CheckInAllocMsg::MemoryAccessTest,
+        )?;
 
         match atomic_op {
             AtomicOp::Min => {
@@ -681,7 +697,12 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
         // be 8-aligned).
         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
-        this.memory.check_ptr_access(place.ptr, place.layout.size, align)?;
+        this.memory.check_ptr_access_align(
+            place.ptr,
+            place.layout.size,
+            align,
+            CheckInAllocMsg::MemoryAccessTest,
+        )?;
 
         let old = this.atomic_exchange_scalar(&place, new, atomic)?;
         this.write_scalar(old, dest)?; // old value is returned
@@ -707,7 +728,12 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
         // be 8-aligned).
         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
-        this.memory.check_ptr_access(place.ptr, place.layout.size, align)?;
+        this.memory.check_ptr_access_align(
+            place.ptr,
+            place.layout.size,
+            align,
+            CheckInAllocMsg::MemoryAccessTest,
+        )?;
 
         let old = this.atomic_compare_exchange_scalar(
             &place,

diff --git a/src/shims/os_str.rs b/src/shims/os_str.rs
@@ -9,7 +9,7 @@ use std::os::unix::ffi::{OsStrExt, OsStringExt};
 #[cfg(windows)]
 use std::os::windows::ffi::{OsStrExt, OsStringExt};
 
-use rustc_target::abi::{LayoutOf, Size};
+use rustc_target::abi::{Align, LayoutOf, Size};
 
 use crate::*;
 
@@ -144,17 +144,14 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         // Store the UTF-16 string.
         let size2 = Size::from_bytes(2);
         let this = self.eval_context_mut();
-        let tcx = &*this.tcx;
-        let ptr = this.force_ptr(sptr)?; // we need to write at least the 0 terminator
-        let alloc = this.memory.get_raw_mut(ptr.alloc_id)?;
+        let mut alloc = this
+            .memory
+            .get_mut(sptr, size2 * string_length, Align::from_bytes(2).unwrap())?
+            .unwrap(); // not a ZST, so we will get a result
         for (offset, wchar) in u16_vec.into_iter().chain(iter::once(0x0000)).enumerate() {
             let offset = u64::try_from(offset).unwrap();
-            alloc.write_scalar(
-                tcx,
-                ptr.offset(size2 * offset, tcx)?,
-                Scalar::from_u16(wchar).into(),
-                size2,
-            )?;
+            alloc
+                .write_scalar(alloc_range(size2 * offset, size2), Scalar::from_u16(wchar).into())?;
         }
         Ok((true, string_length - 1))
     }

diff --git a/src/shims/posix/fs.rs b/src/shims/posix/fs.rs
@@ -677,10 +677,11 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         trace!("Reading from FD {}, size {}", fd, count);
 
         // Check that the *entire* buffer is actually valid memory.
-        this.memory.check_ptr_access(
+        this.memory.check_ptr_access_align(
             buf,
             Size::from_bytes(count),
-            Align::from_bytes(1).unwrap(),
+            Align::ONE,
+            CheckInAllocMsg::MemoryAccessTest,
         )?;
 
         // We cap the number of read bytes to the largest value that we are able to fit in both the
@@ -722,10 +723,11 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         // Isolation check is done via `FileDescriptor` trait.
 
         // Check that the *entire* buffer is actually valid memory.
-        this.memory.check_ptr_access(
+        this.memory.check_ptr_access_align(
             buf,
             Size::from_bytes(count),
-            Align::from_bytes(1).unwrap(),
+            Align::ONE,
+            CheckInAllocMsg::MemoryAccessTest,
         )?;
 
         // We cap the number of written bytes to the largest value that we are able to fit in both the

diff --git a/src/shims/posix/linux/sync.rs b/src/shims/posix/linux/sync.rs
@@ -82,10 +82,11 @@ pub fn futex<'tcx>(
             // Check the pointer for alignment and validity.
             // The API requires `addr` to be a 4-byte aligned pointer, and will
             // use the 4 bytes at the given address as an (atomic) i32.
-            this.memory.check_ptr_access(
+            this.memory.check_ptr_access_align(
                 addr.to_scalar()?,
                 Size::from_bytes(4),
                 Align::from_bytes(4).unwrap(),
+                CheckInAllocMsg::MemoryAccessTest,
             )?;
             // Read an `i32` through the pointer, regardless of any wrapper types.
             // It's not uncommon for `addr` to be passed as another type than `*mut i32`, such as `*const AtomicI32`.

diff --git a/src/stacked_borrows.rs b/src/stacked_borrows.rs
@@ -561,7 +561,7 @@ trait EvalContextPrivExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         );
 
         // Get the allocation. It might not be mutable, so we cannot use `get_mut`.
-        let extra = &this.memory.get_raw(ptr.alloc_id)?.extra;
+        let extra = this.memory.get_alloc_extra(ptr.alloc_id)?;
         let stacked_borrows =
             extra.stacked_borrows.as_ref().expect("we should have Stacked Borrows data");
         // Update the stacks.

diff --git a/tests/compile-fail/data_race/alloc_read_race.rs b/tests/compile-fail/data_race/alloc_read_race.rs
@@ -1,4 +1,5 @@
 // ignore-windows: Concurrency on Windows is not supported yet.
+#![feature(new_uninit)]
 
 use std::thread::spawn;
 use std::ptr::null_mut;
@@ -29,7 +30,7 @@ pub fn main() {
             // Uses relaxed semantics to not generate
             // a release sequence.
             let pointer = &*ptr.0;
-            pointer.store(Box::into_raw(Box::new(MaybeUninit::uninit())), Ordering::Relaxed);
+            pointer.store(Box::into_raw(Box::new_uninit()), Ordering::Relaxed);
         });
 
         let j2 = spawn(move || {