Reflow and fixup comments

src/librustc/mir/interpret/mod.rs

@@ -50,7 +50,8 @@
 pub enum Lock {
     NoLock,
     WriteLock(DynamicLifetime),
-    /// This should never be empty -- that would be a read lock held and nobody there to release it...
+    /// This should never be empty -- that would be a read lock held and nobody
+    /// there to release it...
     ReadLock(Vec<DynamicLifetime>),
 }
 

src/librustc_mir/interpret/cast.rs

@@ -226,7 +226,8 @@ fn cast_from_int(
                 Ok(Scalar::Bits { bits: v, size: 4 })
             },
 
-            // No alignment check needed for raw pointers.  But we have to truncate to target ptr size.
+            // No alignment check needed for raw pointers.
+            // But we have to truncate to target ptr size.
             RawPtr(_) => {
                 Ok(Scalar::Bits {
                     bits: self.memory.truncate_to_ptr(v).0 as u128,
@@ -302,7 +303,8 @@ fn cast_from_float(&self, bits: u128, fty: FloatTy, dest_ty: Ty<'tcx>) -> EvalRe
     fn cast_from_ptr(&self, ptr: Pointer, ty: Ty<'tcx>) -> EvalResult<'tcx, Scalar> {
         use rustc::ty::TyKind::*;
         match ty.sty {
-            // Casting to a reference or fn pointer is not permitted by rustc, no need to support it here.
+            // Casting to a reference or fn pointer is not permitted by rustc,
+            // no need to support it here.
             RawPtr(_) |
             Int(IntTy::Isize) |
             Uint(UintTy::Usize) => Ok(ptr.into()),

src/librustc_mir/interpret/eval_context.rs

@@ -92,7 +92,8 @@ pub struct Frame<'mir, 'tcx: 'mir> {
     pub return_place: Place,
 
     /// The list of locals for this stack frame, stored in order as
-    /// `[return_ptr, arguments..., variables..., temporaries...]`. The locals are stored as `Option<Value>`s.
+    /// `[return_ptr, arguments..., variables..., temporaries...]`.
+    /// The locals are stored as `Option<Value>`s.
     /// `None` represents a local that is currently dead, while a live local
     /// can either directly contain `Scalar` or refer to some part of an `Allocation`.
     pub locals: IndexVec<mir::Local, LocalValue>,
@@ -624,7 +625,8 @@ pub(super) fn pop_stack_frame(&mut self) -> EvalResult<'tcx> {
         match frame.return_to_block {
             StackPopCleanup::MarkStatic(mutable) => {
                 if let Place::Ptr(MemPlace { ptr, .. }) = frame.return_place {
-                    // FIXME: to_ptr()? might be too extreme here, static zsts might reach this under certain conditions
+                    // FIXME: to_ptr()? might be too extreme here,
+                    // static zsts might reach this under certain conditions
                     self.memory.mark_static_initialized(
                         ptr.to_ptr()?.alloc_id,
                         mutable,

src/librustc_mir/interpret/memory.rs

@@ -243,11 +243,12 @@ pub fn deallocate(
 
         let alloc_kind = self.alloc_kind.remove(&ptr.alloc_id).expect("alloc_map out of sync with alloc_kind");
 
-        // It is okay for us to still holds locks on deallocation -- for example, we could store data we own
-        // in a local, and the local could be deallocated (from StorageDead) before the function returns.
-        // However, we should check *something*.  For now, we make sure that there is no conflicting write
-        // lock by another frame.  We *have* to permit deallocation if we hold a read lock.
-        // TODO: Figure out the exact rules here.
+        // It is okay for us to still holds locks on deallocation -- for example, we could store
+        // data we own in a local, and the local could be deallocated (from StorageDead) before the
+        // function returns. However, we should check *something*.  For now, we make sure that there
+        // is no conflicting write lock by another frame.  We *have* to permit deallocation if we
+        // hold a read lock.
+        // FIXME: Figure out the exact rules here.
         M::free_lock(self, ptr.alloc_id, alloc.bytes.len() as u64)?;
 
         if alloc_kind != kind {
@@ -521,13 +522,15 @@ fn get_bytes_unchecked(
         size: Size,
         align: Align,
     ) -> EvalResult<'tcx, &[u8]> {
-        // Zero-sized accesses can use dangling pointers, but they still have to be aligned and non-NULL
+        // Zero-sized accesses can use dangling pointers,
+        // but they still have to be aligned and non-NULL
         self.check_align(ptr.into(), align)?;
         if size.bytes() == 0 {
             return Ok(&[]);
         }
         M::check_locks(self, ptr, size, AccessKind::Read)?;
-        self.check_bounds(ptr.offset(size, self)?, true)?; // if ptr.offset is in bounds, then so is ptr (because offset checks for overflow)
+        // if ptr.offset is in bounds, then so is ptr (because offset checks for overflow)
+        self.check_bounds(ptr.offset(size, self)?, true)?;
         let alloc = self.get(ptr.alloc_id)?;
         assert_eq!(ptr.offset.bytes() as usize as u64, ptr.offset.bytes());
         assert_eq!(size.bytes() as usize as u64, size.bytes());
@@ -542,13 +545,15 @@ fn get_bytes_unchecked_mut(
         size: Size,
         align: Align,
     ) -> EvalResult<'tcx, &mut [u8]> {
-        // Zero-sized accesses can use dangling pointers, but they still have to be aligned and non-NULL
+        // Zero-sized accesses can use dangling pointers,
+        // but they still have to be aligned and non-NULL
         self.check_align(ptr.into(), align)?;
         if size.bytes() == 0 {
             return Ok(&mut []);
         }
         M::check_locks(self, ptr, size, AccessKind::Write)?;
-        self.check_bounds(ptr.offset(size, &*self)?, true)?; // if ptr.offset is in bounds, then so is ptr (because offset checks for overflow)
+        // if ptr.offset is in bounds, then so is ptr (because offset checks for overflow)
+        self.check_bounds(ptr.offset(size, &*self)?, true)?;
         let alloc = self.get_mut(ptr.alloc_id)?;
         assert_eq!(ptr.offset.bytes() as usize as u64, ptr.offset.bytes());
         assert_eq!(size.bytes() as usize as u64, size.bytes());
@@ -774,14 +779,16 @@ pub fn write_repeat(&mut self, ptr: Scalar, val: u8, count: Size) -> EvalResult<
 
     /// Read a *non-ZST* scalar
     pub fn read_scalar(&self, ptr: Pointer, ptr_align: Align, size: Size) -> EvalResult<'tcx, ScalarMaybeUndef> {
-        self.check_relocation_edges(ptr, size)?; // Make sure we don't read part of a pointer as a pointer
+        // Make sure we don't read part of a pointer as a pointer
+        self.check_relocation_edges(ptr, size)?;
         let endianness = self.endianness();
         // get_bytes_unchecked tests alignment
         let bytes = self.get_bytes_unchecked(ptr, size, ptr_align.min(self.int_align(size)))?;
         // Undef check happens *after* we established that the alignment is correct.
         // We must not return Ok() for unaligned pointers!
         if self.check_defined(ptr, size).is_err() {
-            // this inflates undefined bytes to the entire scalar, even if only a few bytes are undefined
+            // this inflates undefined bytes to the entire scalar,
+            // even if only a few bytes are undefined
             return Ok(ScalarMaybeUndef::Undef);
         }
         // Now we do the actual reading

src/librustc_mir/interpret/place.rs

@@ -119,8 +119,9 @@ pub fn to_scalar_ptr_align(self) -> (Scalar, Align) {
     /// Extract the ptr part of the mplace
     #[inline(always)]
     pub fn to_ptr(self) -> EvalResult<'tcx, Pointer> {
-        // At this point, we forget about the alignment information -- the place has been turned into a reference,
-        // and no matter where it came from, it now must be aligned.
+        // At this point, we forget about the alignment information --
+        // the place has been turned into a reference, and no matter where it came from,
+        // it now must be aligned.
         self.to_scalar_ptr_align().0.to_ptr()
     }
 
@@ -582,9 +583,10 @@ fn write_value_to_mplace(
         dest: MPlaceTy<'tcx>,
     ) -> EvalResult<'tcx> {
         let (ptr, ptr_align) = dest.to_scalar_ptr_align();
-        // Note that it is really important that the type here is the right one, and matches the type things are read at.
-        // In case `src_val` is a `ScalarPair`, we don't do any magic here to handle padding properly, which is only
-        // correct if we never look at this data with the wrong type.
+        // Note that it is really important that the type here is the right one, and matches the
+        // type things are read at. In case `src_val` is a `ScalarPair`, we don't do any magic here
+        // to handle padding properly, which is only correct if we never look at this data with the
+        // wrong type.
 
         // Nothing to do for ZSTs, other than checking alignment
         if dest.layout.size.bytes() == 0 {

src/librustc_mir/interpret/step.rs

@@ -108,8 +108,8 @@ fn statement(&mut self, stmt: &mir::Statement<'tcx>) -> EvalResult<'tcx> {
 
         use rustc::mir::StatementKind::*;
 
-        // Some statements (e.g. box) push new stack frames.  We have to record the stack frame number
-        // *before* executing the statement.
+        // Some statements (e.g. box) push new stack frames.
+        // We have to record the stack frame number *before* executing the statement.
         let frame_idx = self.cur_frame();
         self.tcx.span = stmt.source_info.span;
         self.memory.tcx.span = stmt.source_info.span;

src/librustc_mir/interpret/terminator/drop.rs

@@ -24,9 +24,9 @@ pub(crate) fn drop_in_place(
         target: BasicBlock,
     ) -> EvalResult<'tcx> {
         trace!("drop_in_place: {:?},\n  {:?}, {:?}", *place, place.layout.ty, instance);
-        // We take the address of the object.  This may well be unaligned, which is fine for us here.
-        // However, unaligned accesses will probably make the actual drop implementation fail -- a problem shared
-        // by rustc.
+        // We take the address of the object.  This may well be unaligned, which is fine for us
+        // here. However, unaligned accesses will probably make the actual drop implementation fail
+        // -- a problem shared by rustc.
         let place = self.force_allocation(place)?;
 
         let (instance, place) = match place.layout.ty.sty {

src/librustc_mir/interpret/terminator/mod.rs

@@ -185,15 +185,18 @@ pub(super) fn eval_terminator(
             DropAndReplace { .. } => unimplemented!(),
             Resume => unimplemented!(),
             Abort => unimplemented!(),
-            FalseEdges { .. } => bug!("should have been eliminated by `simplify_branches` mir pass"),
-            FalseUnwind { .. } => bug!("should have been eliminated by `simplify_branches` mir pass"),
+            FalseEdges { .. } => bug!("should have been eliminated by\
+                                      `simplify_branches` mir pass"),
+            FalseUnwind { .. } => bug!("should have been eliminated by\
+                                       `simplify_branches` mir pass"),
             Unreachable => return err!(Unreachable),
         }
 
         Ok(())
     }
 
-    /// Decides whether it is okay to call the method with signature `real_sig` using signature `sig`.
+    /// Decides whether it is okay to call the method with signature `real_sig`
+    /// using signature `sig`.
     /// FIXME: This should take into account the platform-dependent ABI description.
     fn check_sig_compat(
         &mut self,
@@ -207,7 +210,7 @@ fn check_ty_compat<'tcx>(ty: Ty<'tcx>, real_ty: Ty<'tcx>) -> bool {
             return match (&ty.sty, &real_ty.sty) {
                 // Permit changing the pointer type of raw pointers and references as well as
                 // mutability of raw pointers.
-                // TODO: Should not be allowed when fat pointers are involved.
+                // FIXME: Should not be allowed when fat pointers are involved.
                 (&ty::RawPtr(_), &ty::RawPtr(_)) => true,
                 (&ty::Ref(_, _, _), &ty::Ref(_, _, _)) => {
                     ty.is_mutable_pointer() == real_ty.is_mutable_pointer()

src/librustc_mir/interpret/validity.rs

@@ -265,7 +265,8 @@ pub fn validate_mplace(
                                 if value.layout.ty.builtin_deref(false).is_some() {
                                     trace!("Recursing below ptr {:#?}", value);
                                     let ptr_place = self.ref_to_mplace(value)?;
-                                    // we have not encountered this pointer+layout combination before
+                                    // we have not encountered this pointer+layout
+                                    // combination before
                                     if seen.insert(ptr_place) {
                                         todo.push((ptr_place, path_clone_and_deref(path)));
                                     }