compiler: Change c_int_width to be an integer type

compiler/rustc_target/src/spec/json.rs

@@ -80,6 +80,12 @@ impl Target {
                     base.$key_name = s;
                 }
             } );
+            ($key_name:ident = $json_name:expr, u64 as $int_ty:ty) => ( {
+                let name = $json_name;
+                if let Some(s) = obj.remove(name).and_then(|b| b.as_u64()) {
+                    base.$key_name = s as $int_ty;
+                }
+            } );
             ($key_name:ident, bool) => ( {
                 let name = (stringify!($key_name)).replace("_", "-");
                 if let Some(s) = obj.remove(&name).and_then(|b| b.as_bool()) {
@@ -554,7 +560,7 @@ impl Target {
             }
         }
 
-        key!(c_int_width = "target-c-int-width");
+        key!(c_int_width = "target-c-int-width", u64 as u16);
         key!(c_enum_min_bits, Option<u64>); // if None, matches c_int_width
         key!(os);
         key!(env);

compiler/rustc_target/src/spec/mod.rs

@@ -2213,18 +2213,10 @@ impl Target {
             });
         }
 
-        dl.c_enum_min_size = self
-            .c_enum_min_bits
-            .map_or_else(
-                || {
-                    self.c_int_width
-                        .parse()
-                        .map_err(|_| String::from("failed to parse c_int_width"))
-                },
-                Ok,
-            )
-            .and_then(|i| Integer::from_size(Size::from_bits(i)))
-            .map_err(|err| TargetDataLayoutErrors::InvalidBitsSize { err })?;
+        dl.c_enum_min_size = Integer::from_size(Size::from_bits(
+            self.c_enum_min_bits.unwrap_or(self.c_int_width as _),
+        ))
+        .map_err(|err| TargetDataLayoutErrors::InvalidBitsSize { err })?;
 
         Ok(dl)
     }
@@ -2286,7 +2278,7 @@ pub struct TargetOptions {
     /// Used as the `target_endian` `cfg` variable. Defaults to little endian.
     pub endian: Endian,
     /// Width of c_int type. Defaults to "32".
-    pub c_int_width: StaticCow<str>,
+    pub c_int_width: u16,
     /// OS name to use for conditional compilation (`target_os`). Defaults to "none".
     /// "none" implies a bare metal target without `std` library.
     /// A couple of targets having `std` also use "unknown" as an `os` value,
@@ -2783,7 +2775,7 @@ impl Default for TargetOptions {
     fn default() -> TargetOptions {
         TargetOptions {
             endian: Endian::Little,
-            c_int_width: "32".into(),
+            c_int_width: 32,
             os: "none".into(),
             env: "".into(),
             abi: "".into(),