interpret: use AllocRange in UninitByteAccess

[rust.git] / compiler / rustc_middle / src / mir / interpret / allocation.rs

diff --git a/compiler/rustc_middle/src/mir/interpret/allocation.rs b/compiler/rustc_middle/src/mir/interpret/allocation.rs
index 10c4ea63a68b2677158ef47e1015d66329f3bb11..ae333846f067c73fce5f891d9831ed27fc5c28a8 100644 (file)
--- a/compiler/rustc_middle/src/mir/interpret/allocation.rs
+++ b/compiler/rustc_middle/src/mir/interpret/allocation.rs
@@ -160,12 +160,18 @@ pub fn to_interp_error<'tcx>(self, alloc_id: AllocId) -> InterpError<'tcx> {
 }
 
 /// The information that makes up a memory access: offset and size.
-#[derive(Copy, Clone, Debug)]
+#[derive(Copy, Clone)]
 pub struct AllocRange {
     pub start: Size,
     pub size: Size,
 }
 
+impl fmt::Debug for AllocRange {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "[{:#x}..{:#x}]", self.start.bytes(), self.end().bytes())
+    }
+}
+
 /// Free-starting constructor for less syntactic overhead.
 #[inline(always)]
 pub fn alloc_range(start: Size, size: Size) -> AllocRange {
@@ -173,6 +179,11 @@ pub fn alloc_range(start: Size, size: Size) -> AllocRange {
 }
 
 impl AllocRange {
+    #[inline]
+    pub fn from(r: Range<Size>) -> Self {
+        alloc_range(r.start, r.end - r.start) // `Size` subtraction (overflow-checked)
+    }
+
     #[inline(always)]
     pub fn end(self) -> Size {
         self.start + self.size // This does overflow checking.
@@ -537,21 +548,26 @@ pub fn write_uninit(&mut self, cx: &impl HasDataLayout, range: AllocRange) -> Al
 /// Relocations.
 impl<Tag: Copy, Extra> Allocation<Tag, Extra> {
     /// Returns all relocations overlapping with the given pointer-offset pair.
-    pub fn get_relocations(&self, cx: &impl HasDataLayout, range: AllocRange) -> &[(Size, Tag)] {
+    fn get_relocations(&self, cx: &impl HasDataLayout, range: AllocRange) -> &[(Size, Tag)] {
         // We have to go back `pointer_size - 1` bytes, as that one would still overlap with
         // the beginning of this range.
         let start = range.start.bytes().saturating_sub(cx.data_layout().pointer_size.bytes() - 1);
         self.relocations.range(Size::from_bytes(start)..range.end())
     }
 
+    /// Returns whether this allocation has relocations overlapping with the given range.
+    ///
+    /// Note: this function exists to allow `get_relocations` to be private, in order to somewhat
+    /// limit access to relocations outside of the `Allocation` abstraction.
+    ///
+    pub fn has_relocations(&self, cx: &impl HasDataLayout, range: AllocRange) -> bool {
+        !self.get_relocations(cx, range).is_empty()
+    }
+
     /// Checks that there are no relocations overlapping with the given range.
     #[inline(always)]
     fn check_relocations(&self, cx: &impl HasDataLayout, range: AllocRange) -> AllocResult {
-        if self.get_relocations(cx, range).is_empty() {
-            Ok(())
-        } else {
-            Err(AllocError::ReadPointerAsBytes)
-        }
+        if self.has_relocations(cx, range) { Err(AllocError::ReadPointerAsBytes) } else { Ok(()) }
     }
 
     /// Removes all relocations inside the given range.
@@ -1084,9 +1100,9 @@ impl InitMask {
     /// Returns `Ok(())` if it's initialized. Otherwise returns a range of byte
     /// indexes for the first contiguous span of the uninitialized access.
     #[inline]
-    pub fn is_range_initialized(&self, start: Size, end: Size) -> Result<(), Range<Size>> {
+    pub fn is_range_initialized(&self, start: Size, end: Size) -> Result<(), AllocRange> {
         if end > self.len {
-            return Err(self.len..end);
+            return Err(AllocRange::from(self.len..end));
         }
 
         let uninit_start = self.find_bit(start, end, false);
@@ -1094,7 +1110,7 @@ pub fn is_range_initialized(&self, start: Size, end: Size) -> Result<(), Range<S
         match uninit_start {
             Some(uninit_start) => {
                 let uninit_end = self.find_bit(uninit_start, end, true).unwrap_or(end);
-                Err(uninit_start..uninit_end)
+                Err(AllocRange::from(uninit_start..uninit_end))
             }
             None => Ok(()),
         }
@@ -1165,19 +1181,17 @@ impl<Tag: Copy, Extra> Allocation<Tag, Extra> {
     ///
     /// Returns `Ok(())` if it's initialized. Otherwise returns the range of byte
     /// indexes of the first contiguous uninitialized access.
-    fn is_init(&self, range: AllocRange) -> Result<(), Range<Size>> {
+    fn is_init(&self, range: AllocRange) -> Result<(), AllocRange> {
         self.init_mask.is_range_initialized(range.start, range.end()) // `Size` addition
     }
 
     /// 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, range: AllocRange) -> AllocResult {
-        self.is_init(range).map_err(|idx_range| {
+        self.is_init(range).map_err(|uninit_range| {
             AllocError::InvalidUninitBytes(Some(UninitBytesAccess {
-                access_offset: range.start,
-                access_size: range.size,
-                uninit_offset: idx_range.start,
-                uninit_size: idx_range.end - idx_range.start, // `Size` subtraction
+                access: range,
+                uninit: uninit_range,
             }))
         })
     }