rustc_target: move abi::Niche from rustc::ty::layout.

src/librustc/ty/layout.rs

@@ -2222,57 +2222,6 @@ where
     }
 }
 
-struct Niche {
-    offset: Size,
-    scalar: Scalar,
-}
-
-impl Niche {
-    fn available<C: HasDataLayout>(&self, cx: &C) -> u128 {
-        let Scalar { value, valid_range: ref v } = self.scalar;
-        let bits = value.size(cx).bits();
-        assert!(bits <= 128);
-        let max_value = !0u128 >> (128 - bits);
-
-        // Find out how many values are outside the valid range.
-        let niche = v.end().wrapping_add(1)..*v.start();
-        niche.end.wrapping_sub(niche.start) & max_value
-    }
-
-    fn reserve<C: HasDataLayout>(&self, cx: &C, count: u128) -> Option<(u128, Scalar)> {
-        assert!(count > 0);
-
-        let Scalar { value, valid_range: ref v } = self.scalar;
-        let bits = value.size(cx).bits();
-        assert!(bits <= 128);
-        let max_value = !0u128 >> (128 - bits);
-
-        if count > max_value {
-            return None;
-        }
-
-        // Compute the range of invalid values being reserved.
-        let start = v.end().wrapping_add(1) & max_value;
-        let end = v.end().wrapping_add(count) & max_value;
-
-        // If the `end` of our range is inside the valid range,
-        // then we ran out of invalid values.
-        // FIXME(eddyb) abstract this with a wraparound range type.
-        let valid_range_contains = |x| {
-            if v.start() <= v.end() {
-                *v.start() <= x && x <= *v.end()
-            } else {
-                *v.start() <= x || x <= *v.end()
-            }
-        };
-        if valid_range_contains(end) {
-            return None;
-        }
-
-        Some((start, Scalar { value, valid_range: *v.start()..=end }))
-    }
-}
-
 impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
     /// Find the offset of a niche leaf field, starting from
     /// the given type and recursing through aggregates.

src/librustc_target/abi/mod.rs

@@ -878,6 +878,57 @@ pub enum DiscriminantKind {
     },
 }
 
+pub struct Niche {
+    pub offset: Size,
+    pub scalar: Scalar,
+}
+
+impl Niche {
+    pub fn available<C: HasDataLayout>(&self, cx: &C) -> u128 {
+        let Scalar { value, valid_range: ref v } = self.scalar;
+        let bits = value.size(cx).bits();
+        assert!(bits <= 128);
+        let max_value = !0u128 >> (128 - bits);
+
+        // Find out how many values are outside the valid range.
+        let niche = v.end().wrapping_add(1)..*v.start();
+        niche.end.wrapping_sub(niche.start) & max_value
+    }
+
+    pub fn reserve<C: HasDataLayout>(&self, cx: &C, count: u128) -> Option<(u128, Scalar)> {
+        assert!(count > 0);
+
+        let Scalar { value, valid_range: ref v } = self.scalar;
+        let bits = value.size(cx).bits();
+        assert!(bits <= 128);
+        let max_value = !0u128 >> (128 - bits);
+
+        if count > max_value {
+            return None;
+        }
+
+        // Compute the range of invalid values being reserved.
+        let start = v.end().wrapping_add(1) & max_value;
+        let end = v.end().wrapping_add(count) & max_value;
+
+        // If the `end` of our range is inside the valid range,
+        // then we ran out of invalid values.
+        // FIXME(eddyb) abstract this with a wraparound range type.
+        let valid_range_contains = |x| {
+            if v.start() <= v.end() {
+                *v.start() <= x && x <= *v.end()
+            } else {
+                *v.start() <= x || x <= *v.end()
+            }
+        };
+        if valid_range_contains(end) {
+            return None;
+        }
+
+        Some((start, Scalar { value, valid_range: *v.start()..=end }))
+    }
+}
+
 #[derive(PartialEq, Eq, Hash, Debug)]
 pub struct LayoutDetails {
     pub variants: Variants,