rustc_back: Remove unused code

Downstream consumers of Svh now use the ToString and Hash traits
whenever possible

src/librustc_back/svh.rs

@@ -51,15 +51,6 @@ use std::hash::{Hash, SipHasher, Hasher};
 use syntax::ast;
 use syntax::visit;
 
-fn hex(b: u64) -> char {
-    let b = (b & 0xf) as u8;
-    let b = match b {
-        0 ... 9 => '0' as u8 + b,
-        _ => 'a' as u8 + b - 10,
-    };
-    b as char
-}
-
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct Svh {
     raw: u64,
@@ -68,7 +59,7 @@ pub struct Svh {
 impl Svh {
     pub fn new(hash: &str) -> Svh {
         assert!(hash.len() == 16);
-        // Ideally we'd just reverse the nibbles on LE machines during as_string, unfortunately
+        // Ideally we'd just reverse the nibbles on LE machines during to_string, unfortunately
         // this would break the abi so I guess we're just doing this now.
 
         let s = if cfg!(target_endian = "big") {
@@ -82,10 +73,6 @@ impl Svh {
         }
     }
 
-    pub fn as_string(&self) -> String {
-        (0..64).step_by(4).map(|i| hex(self.raw >> i)).collect()
-    }
-
     pub fn calculate(metadata: &Vec<String>, krate: &ast::Crate) -> Svh {
         // FIXME (#14132): This is better than it used to be, but it still not
         // ideal. We now attempt to hash only the relevant portions of the
@@ -136,7 +123,7 @@ impl Hash for Svh {
 
 impl fmt::Display for Svh {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.pad(&self.as_string())
+        f.pad(&self.to_string())
     }
 }