Auto merge of #74664 - pnadon:Miri-rename-undef-uninit, r=RalfJung

Miri rename undef uninit

Renamed parts of code within the `librustc_middle/mir/interpret/` directory.

Related issue [#71193](#71193)

src/librustc_codegen_ssa/mir/block.rs

@@ -883,7 +883,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                                 let ptr = Pointer::new(AllocId(0), offset);
                                 alloc
                                     .read_scalar(&bx, ptr, size)
-                                    .and_then(|s| s.not_undef())
+                                    .and_then(|s| s.check_init())
                                     .unwrap_or_else(|e| {
                                         bx.tcx().sess.span_err(
                                             span,

src/librustc_middle/mir/interpret/allocation.rs

@@ -105,7 +105,7 @@ impl<Tag> Allocation<Tag> {
         Allocation::from_bytes(slice, Align::from_bytes(1).unwrap())
     }
 
-    pub fn undef(size: Size, align: Align) -> Self {
+    pub fn uninit(size: Size, align: Align) -> Self {
         Allocation {
             bytes: vec![0; size.bytes_usize()],
             relocations: Relocations::new(),
@@ -153,7 +153,7 @@ impl<Tag, Extra> Allocation<Tag, Extra> {
         self.size.bytes_usize()
     }
 
-    /// Looks at a slice which may describe undefined bytes or describe a relocation. This differs
+    /// Looks at a slice which may describe uninitialized bytes or describe a relocation. This differs
     /// from `get_bytes_with_undef_and_ptr` in that it does no relocation checks (even on the
     /// edges) at all. It further ignores `AllocationExtra` callbacks.
     /// This must not be used for reads affecting the interpreter execution.
@@ -192,7 +192,7 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
         offset.bytes_usize()..end
     }
 
-    /// The last argument controls whether we error out when there are undefined
+    /// The last argument controls whether we error out when there are uninitialized
     /// or pointer bytes. You should never call this, call `get_bytes` or
     /// `get_bytes_with_undef_and_ptr` instead,
     ///
@@ -206,12 +206,12 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
         cx: &impl HasDataLayout,
         ptr: Pointer<Tag>,
         size: Size,
-        check_defined_and_ptr: bool,
+        check_init_and_ptr: bool,
     ) -> InterpResult<'tcx, &[u8]> {
         let range = self.check_bounds(ptr.offset, size);
 
-        if check_defined_and_ptr {
-            self.check_defined(ptr, size)?;
+        if check_init_and_ptr {
+            self.check_init(ptr, size)?;
             self.check_relocations(cx, ptr, size)?;
         } else {
             // We still don't want relocations on the *edges*.
@@ -239,7 +239,7 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
         self.get_bytes_internal(cx, ptr, size, true)
     }
 
-    /// It is the caller's responsibility to handle undefined and pointer bytes.
+    /// It is the caller's responsibility to handle uninitialized and pointer bytes.
     /// However, this still checks that there are no relocations on the *edges*.
     ///
     /// It is the caller's responsibility to check bounds and alignment beforehand.
@@ -267,7 +267,7 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
     ) -> InterpResult<'tcx, &mut [u8]> {
         let range = self.check_bounds(ptr.offset, size);
 
-        self.mark_definedness(ptr, size, true);
+        self.mark_init(ptr, size, true);
         self.clear_relocations(cx, ptr, size)?;
 
         AllocationExtra::memory_written(self, ptr, size)?;
@@ -303,7 +303,7 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
 
     /// Validates that `ptr.offset` and `ptr.offset + size` do not point to the middle of a
     /// relocation. If `allow_ptr_and_undef` is `false`, also enforces that the memory in the
-    /// given range contains neither relocations nor undef bytes.
+    /// given range contains neither relocations nor uninitialized bytes.
     pub fn check_bytes(
         &self,
         cx: &impl HasDataLayout,
@@ -313,9 +313,9 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
     ) -> InterpResult<'tcx> {
         // Check bounds and relocations on the edges.
         self.get_bytes_with_undef_and_ptr(cx, ptr, size)?;
-        // Check undef and ptr.
+        // Check uninit and ptr.
         if !allow_ptr_and_undef {
-            self.check_defined(ptr, size)?;
+            self.check_init(ptr, size)?;
             self.check_relocations(cx, ptr, size)?;
         }
         Ok(())
@@ -364,7 +364,7 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
         let bytes = self.get_bytes_with_undef_and_ptr(cx, ptr, size)?;
         // Uninit check happens *after* we established that the alignment is correct.
         // We must not return `Ok()` for unaligned pointers!
-        if self.is_defined(ptr, size).is_err() {
+        if self.is_init(ptr, size).is_err() {
             // This inflates uninitialized bytes to the entire scalar, even if only a few
             // bytes are uninitialized.
             return Ok(ScalarMaybeUninit::Uninit);
@@ -416,7 +416,7 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
         let val = match val {
             ScalarMaybeUninit::Scalar(scalar) => scalar,
             ScalarMaybeUninit::Uninit => {
-                self.mark_definedness(ptr, type_size, false);
+                self.mark_init(ptr, type_size, false);
                 return Ok(());
             }
         };
@@ -512,7 +512,7 @@ impl<'tcx, Tag: Copy, Extra> Allocation<Tag, Extra> {
         let start = ptr.offset;
         let end = start + size; // `Size` addition
 
-        // Mark parts of the outermost relocations as undefined if they partially fall outside the
+        // Mark parts of the outermost relocations as uninitialized if they partially fall outside the
         // given range.
         if first < start {
             self.init_mask.set_range(first, start, false);
@@ -542,20 +542,20 @@ impl<'tcx, Tag: Copy, Extra> Allocation<Tag, Extra> {
     }
 }
 
-/// Undefined bytes.
+/// Uninitialized bytes.
 impl<'tcx, Tag: Copy, Extra> Allocation<Tag, Extra> {
-    /// Checks whether the given range  is entirely defined.
+    /// Checks whether the given range  is entirely initialized.
     ///
-    /// Returns `Ok(())` if it's defined. Otherwise returns the range of byte
-    /// indexes of the first contiguous undefined access.
-    fn is_defined(&self, ptr: Pointer<Tag>, size: Size) -> Result<(), Range<Size>> {
+    /// Returns `Ok(())` if it's initialized. Otherwise returns the range of byte
+    /// indexes of the first contiguous uninitialized access.
+    fn is_init(&self, ptr: Pointer<Tag>, size: Size) -> Result<(), Range<Size>> {
         self.init_mask.is_range_initialized(ptr.offset, ptr.offset + size) // `Size` addition
     }
 
-    /// Checks that a range of bytes is defined. If not, returns the `InvalidUndefBytes`
-    /// error which will report the first range of bytes which is undefined.
-    fn check_defined(&self, ptr: Pointer<Tag>, size: Size) -> InterpResult<'tcx> {
-        self.is_defined(ptr, size).or_else(|idx_range| {
+    /// Checks that a range of bytes is initialized. If not, returns the `InvalidUninitBytes`
+    /// error which will report the first range of bytes which is uninitialized.
+    fn check_init(&self, ptr: Pointer<Tag>, size: Size) -> InterpResult<'tcx> {
+        self.is_init(ptr, size).or_else(|idx_range| {
             throw_ub!(InvalidUninitBytes(Some(Box::new(UninitBytesAccess {
                 access_ptr: ptr.erase_tag(),
                 access_size: size,
@@ -565,44 +565,44 @@ impl<'tcx, Tag: Copy, Extra> Allocation<Tag, Extra> {
         })
     }
 
-    pub fn mark_definedness(&mut self, ptr: Pointer<Tag>, size: Size, new_state: bool) {
+    pub fn mark_init(&mut self, ptr: Pointer<Tag>, size: Size, is_init: bool) {
         if size.bytes() == 0 {
             return;
         }
-        self.init_mask.set_range(ptr.offset, ptr.offset + size, new_state);
+        self.init_mask.set_range(ptr.offset, ptr.offset + size, is_init);
     }
 }
 
-/// Run-length encoding of the undef mask.
+/// Run-length encoding of the uninit mask.
 /// Used to copy parts of a mask multiple times to another allocation.
-pub struct AllocationDefinedness {
-    /// The definedness of the first range.
+pub struct InitMaskCompressed {
+    /// Whether the first range is initialized.
     initial: bool,
     /// The lengths of ranges that are run-length encoded.
-    /// The definedness of the ranges alternate starting with `initial`.
+    /// The initialization state of the ranges alternate starting with `initial`.
     ranges: smallvec::SmallVec<[u64; 1]>,
 }
 
-impl AllocationDefinedness {
-    pub fn all_bytes_undef(&self) -> bool {
-        // The `ranges` are run-length encoded and of alternating definedness.
-        // So if `ranges.len() > 1` then the second block is a range of defined.
+impl InitMaskCompressed {
+    pub fn no_bytes_init(&self) -> bool {
+        // The `ranges` are run-length encoded and of alternating initialization state.
+        // So if `ranges.len() > 1` then the second block is an initialized range.
         !self.initial && self.ranges.len() == 1
     }
 }
 
-/// Transferring the definedness mask to other allocations.
+/// Transferring the initialization mask to other allocations.
 impl<Tag, Extra> Allocation<Tag, Extra> {
-    /// Creates a run-length encoding of the undef mask.
-    pub fn compress_undef_range(&self, src: Pointer<Tag>, size: Size) -> AllocationDefinedness {
+    /// Creates a run-length encoding of the initialization mask.
+    pub fn compress_undef_range(&self, src: Pointer<Tag>, size: Size) -> InitMaskCompressed {
         // Since we are copying `size` bytes from `src` to `dest + i * size` (`for i in 0..repeat`),
-        // a naive undef mask copying algorithm would repeatedly have to read the undef mask from
+        // a naive initialization mask copying algorithm would repeatedly have to read the initialization mask from
         // the source and write it to the destination. Even if we optimized the memory accesses,
         // we'd be doing all of this `repeat` times.
-        // Therefore we precompute a compressed version of the undef mask of the source value and
+        // Therefore we precompute a compressed version of the initialization mask of the source value and
         // then write it back `repeat` times without computing any more information from the source.
 
-        // A precomputed cache for ranges of defined/undefined bits
+        // A precomputed cache for ranges of initialized / uninitialized bits
         // 0000010010001110 will become
         // `[5, 1, 2, 1, 3, 3, 1]`,
         // where each element toggles the state.
@@ -613,7 +613,7 @@ impl<Tag, Extra> Allocation<Tag, Extra> {
         let mut cur = initial;
 
         for i in 1..size.bytes() {
-            // FIXME: optimize to bitshift the current undef block's bits and read the top bit.
+            // FIXME: optimize to bitshift the current uninitialized block's bits and read the top bit.
             if self.init_mask.get(src.offset + Size::from_bytes(i)) == cur {
                 cur_len += 1;
             } else {
@@ -625,13 +625,13 @@ impl<Tag, Extra> Allocation<Tag, Extra> {
 
         ranges.push(cur_len);
 
-        AllocationDefinedness { ranges, initial }
+        InitMaskCompressed { ranges, initial }
     }
 
-    /// Applies multiple instances of the run-length encoding to the undef mask.
-    pub fn mark_compressed_undef_range(
+    /// Applies multiple instances of the run-length encoding to the initialization mask.
+    pub fn mark_compressed_init_range(
         &mut self,
-        defined: &AllocationDefinedness,
+        defined: &InitMaskCompressed,
         dest: Pointer<Tag>,
         size: Size,
         repeat: u64,
@@ -740,7 +740,7 @@ impl<Tag: Copy, Extra> Allocation<Tag, Extra> {
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-// Undefined byte tracking
+// Uninitialized byte tracking
 ////////////////////////////////////////////////////////////////////////////////
 
 type Block = u64;
@@ -778,11 +778,11 @@ impl InitMask {
 
         match idx {
             Some(idx) => {
-                let undef_end = (idx.bytes()..end.bytes())
+                let uninit_end = (idx.bytes()..end.bytes())
                     .map(Size::from_bytes)
                     .find(|&i| self.get(i))
                     .unwrap_or(end);
-                Err(idx..undef_end)
+                Err(idx..uninit_end)
             }
             None => Ok(()),
         }

src/librustc_middle/mir/interpret/value.rs

@@ -606,7 +606,7 @@ impl<'tcx, Tag> ScalarMaybeUninit<Tag> {
     }
 
     #[inline]
-    pub fn not_undef(self) -> InterpResult<'static, Scalar<Tag>> {
+    pub fn check_init(self) -> InterpResult<'static, Scalar<Tag>> {
         match self {
             ScalarMaybeUninit::Scalar(scalar) => Ok(scalar),
             ScalarMaybeUninit::Uninit => throw_ub!(InvalidUninitBytes(None)),
@@ -615,72 +615,72 @@ impl<'tcx, Tag> ScalarMaybeUninit<Tag> {
 
     #[inline(always)]
     pub fn to_bool(self) -> InterpResult<'tcx, bool> {
-        self.not_undef()?.to_bool()
+        self.check_init()?.to_bool()
     }
 
     #[inline(always)]
     pub fn to_char(self) -> InterpResult<'tcx, char> {
-        self.not_undef()?.to_char()
+        self.check_init()?.to_char()
     }
 
     #[inline(always)]
     pub fn to_f32(self) -> InterpResult<'tcx, Single> {
-        self.not_undef()?.to_f32()
+        self.check_init()?.to_f32()
     }
 
     #[inline(always)]
     pub fn to_f64(self) -> InterpResult<'tcx, Double> {
-        self.not_undef()?.to_f64()
+        self.check_init()?.to_f64()
     }
 
     #[inline(always)]
     pub fn to_u8(self) -> InterpResult<'tcx, u8> {
-        self.not_undef()?.to_u8()
+        self.check_init()?.to_u8()
     }
 
     #[inline(always)]
     pub fn to_u16(self) -> InterpResult<'tcx, u16> {
-        self.not_undef()?.to_u16()
+        self.check_init()?.to_u16()
     }
 
     #[inline(always)]
     pub fn to_u32(self) -> InterpResult<'tcx, u32> {
-        self.not_undef()?.to_u32()
+        self.check_init()?.to_u32()
     }
 
     #[inline(always)]
     pub fn to_u64(self) -> InterpResult<'tcx, u64> {
-        self.not_undef()?.to_u64()
+        self.check_init()?.to_u64()
     }
 
     #[inline(always)]
     pub fn to_machine_usize(self, cx: &impl HasDataLayout) -> InterpResult<'tcx, u64> {
-        self.not_undef()?.to_machine_usize(cx)
+        self.check_init()?.to_machine_usize(cx)
     }
 
     #[inline(always)]
     pub fn to_i8(self) -> InterpResult<'tcx, i8> {
-        self.not_undef()?.to_i8()
+        self.check_init()?.to_i8()
     }
 
     #[inline(always)]
     pub fn to_i16(self) -> InterpResult<'tcx, i16> {
-        self.not_undef()?.to_i16()
+        self.check_init()?.to_i16()
     }
 
     #[inline(always)]
     pub fn to_i32(self) -> InterpResult<'tcx, i32> {
-        self.not_undef()?.to_i32()
+        self.check_init()?.to_i32()
     }
 
     #[inline(always)]
     pub fn to_i64(self) -> InterpResult<'tcx, i64> {
-        self.not_undef()?.to_i64()
+        self.check_init()?.to_i64()
     }
 
     #[inline(always)]
     pub fn to_machine_isize(self, cx: &impl HasDataLayout) -> InterpResult<'tcx, i64> {
-        self.not_undef()?.to_machine_isize(cx)
+        self.check_init()?.to_machine_isize(cx)
     }
 }
 

src/librustc_mir/const_eval/eval_queries.rs

@@ -154,7 +154,7 @@ pub(super) fn op_to_const<'tcx>(
                 ScalarMaybeUninit::Uninit => to_const_value(op.assert_mem_place(ecx)),
             },
             Immediate::ScalarPair(a, b) => {
-                let (data, start) = match a.not_undef().unwrap() {
+                let (data, start) = match a.check_init().unwrap() {
                     Scalar::Ptr(ptr) => {
                         (ecx.tcx.global_alloc(ptr.alloc_id).unwrap_memory(), ptr.offset.bytes())
                     }