Implement missing ABI structures in StableMIR

compiler/stable_mir/src/target.rs

@@ -30,21 +30,29 @@ pub enum Endian {
 }
 
 /// Represent the size of a component.
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
 pub struct MachineSize {
     num_bits: usize,
 }
 
 impl MachineSize {
+    #[inline(always)]
     pub fn bytes(self) -> usize {
         self.num_bits / 8
     }
 
+    #[inline(always)]
     pub fn bits(self) -> usize {
         self.num_bits
     }
 
+    #[inline(always)]
     pub fn from_bits(num_bits: usize) -> MachineSize {
         MachineSize { num_bits }
     }
+
+    #[inline]
+    pub fn unsigned_int_max(self) -> Option<u128> {
+        (self.num_bits <= 128).then(|| u128::MAX >> (128 - self.bits()))
+    }
 }