Wrap FunctionName in a newtype struct.

Function names display differently than normal strings since they need
quotes and escaping.

Move the FunctionName type into its own module.

cranelift/filetests/parser/rewrite.cton

@@ -29,7 +29,7 @@ ebb100(v20: i32):
     vx200 = iadd v20, v1000
     jump ebb100(v1000)
 }
-; sameln: function "use_value"() {
+; sameln: function use_value() {
 ; nextln: ebb0(vx0: i32):
 ; nextln:     v0 = iadd_imm vx0, 5
 ; nextln:     v1 = iadd vx0, v0

cranelift/src/libcretonne/ir/funcname.rs

@@ -0,0 +1,77 @@
+//! Function names.
+//!
+//! The name of a function doesn't have any meaning to Cretonne which compiles functions
+//! independently.
+
+use std::fmt::{self, Write};
+use std::ascii::AsciiExt;
+
+/// The name of a function can be any UTF-8 string.
+///
+/// Function names are mostly a testing and debugging tool.
+/// In particular, `.cton` files use function names to identify functions.
+#[derive(Debug, Clone, PartialEq, Eq, Default)]
+pub struct FunctionName(String);
+
+impl FunctionName {
+    pub fn new<S: Into<String>>(s: S) -> FunctionName {
+        FunctionName(s.into())
+    }
+}
+
+fn is_id_start(c: char) -> bool {
+    c.is_ascii() && (c == '_' || c.is_alphabetic())
+}
+
+fn is_id_continue(c: char) -> bool {
+    c.is_ascii() && (c == '_' || c.is_alphanumeric())
+}
+
+// The function name may need quotes if it doesn't parse as an identifier.
+fn needs_quotes(name: &str) -> bool {
+    let mut iter = name.chars();
+    if let Some(ch) = iter.next() {
+        !is_id_start(ch) || !iter.all(is_id_continue)
+    } else {
+        // A blank function name needs quotes.
+        true
+    }
+}
+
+impl fmt::Display for FunctionName {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        if needs_quotes(&self.0) {
+            try!(f.write_char('"'));
+            for c in self.0.chars().flat_map(char::escape_default) {
+                try!(f.write_char(c));
+            }
+            f.write_char('"')
+        } else {
+            f.write_str(&self.0)
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{needs_quotes, FunctionName};
+
+    #[test]
+    fn quoting() {
+        assert_eq!(needs_quotes(""), true);
+        assert_eq!(needs_quotes("x"), false);
+        assert_eq!(needs_quotes(" "), true);
+        assert_eq!(needs_quotes("0"), true);
+        assert_eq!(needs_quotes("x0"), false);
+    }
+
+    #[test]
+    fn escaping() {
+        assert_eq!(FunctionName::new("").to_string(), "\"\"");
+        assert_eq!(FunctionName::new("x").to_string(), "x");
+        assert_eq!(FunctionName::new(" ").to_string(), "\" \"");
+        assert_eq!(FunctionName::new(" \n").to_string(), "\" \\n\"");
+        assert_eq!(FunctionName::new("a\u{1000}v").to_string(),
+                   "\"a\\u{1000}v\"");
+    }
+}

cranelift/src/libcretonne/ir/function.rs

@@ -52,7 +52,7 @@ impl Function {
 
     /// Create a new empty, anomymous function.
     pub fn new() -> Function {
-        Self::with_name_signature(FunctionName::new(), Signature::new())
+        Self::with_name_signature(FunctionName::default(), Signature::new())
     }
 
     /// Get the signature of this function.

cranelift/src/libcretonne/ir/mod.rs

@@ -10,8 +10,10 @@ pub mod jumptable;
 pub mod dfg;
 pub mod layout;
 pub mod function;
+mod funcname;
 
-pub use ir::types::{Type, FunctionName, Signature};
+pub use ir::funcname::FunctionName;
+pub use ir::types::{Type, Signature};
 pub use ir::entities::{Ebb, Inst, Value, StackSlot, JumpTable};
 pub use ir::instructions::{Opcode, InstructionData};
 pub use ir::stackslot::StackSlotData;

cranelift/src/libcretonne/ir/types.rs

@@ -191,12 +191,6 @@ impl Default for Type {
 //
 // ====--------------------------------------------------------------------------------------====//
 
-/// The name of a function can be any UTF-8 string.
-///
-/// Function names are mostly a testing and debugging tool. In partucular, `.cton` files use
-/// function names to identify functions.
-pub type FunctionName = String;
-
 /// Function argument extension options.
 ///
 /// On some architectures, small integer function arguments are extended to the width of a

cranelift/src/libcretonne/write.rs

@@ -29,30 +29,8 @@ pub fn write_function(w: &mut Write, func: &Function) -> Result {
 //
 // ====--------------------------------------------------------------------------------------====//
 
-// The function name may need quotes if it doesn't parse as an identifier.
-fn needs_quotes(name: &str) -> bool {
-    let mut iter = name.chars();
-    if let Some(ch) = iter.next() {
-        !ch.is_alphabetic() || !iter.all(char::is_alphanumeric)
-    } else {
-        // A blank function name needs quotes.
-        true
-    }
-}
-
-// Use Rust's escape_default which provides a few simple \t \r \n \' \" \\ escapes and uses
-// \u{xxxx} for anything else outside the ASCII printable range.
-fn escaped(name: &str) -> String {
-    name.chars().flat_map(char::escape_default).collect()
-}
-
 fn write_spec(w: &mut Write, func: &Function) -> Result {
-    let sig = func.own_signature();
-    if !needs_quotes(&func.name) {
-        write!(w, "function {}{}", func.name, sig)
-    } else {
-        write!(w, "function \"{}\"{}", escaped(&func.name), sig)
-    }
+    write!(w, "function {}{}", func.name, func.own_signature())
 }
 
 fn write_preamble(w: &mut Write, func: &Function) -> result::Result<bool, Error> {
@@ -208,34 +186,15 @@ pub fn write_instruction(w: &mut Write, func: &Function, inst: Inst) -> Result {
 
 #[cfg(test)]
 mod tests {
-    use super::{needs_quotes, escaped};
-    use ir::{Function, StackSlotData};
+    use ir::{Function, FunctionName, StackSlotData};
     use ir::types;
 
-    #[test]
-    fn quoting() {
-        assert_eq!(needs_quotes(""), true);
-        assert_eq!(needs_quotes("x"), false);
-        assert_eq!(needs_quotes(" "), true);
-        assert_eq!(needs_quotes("0"), true);
-        assert_eq!(needs_quotes("x0"), false);
-    }
-
-    #[test]
-    fn escaping() {
-        assert_eq!(escaped(""), "");
-        assert_eq!(escaped("x"), "x");
-        assert_eq!(escaped(" "), " ");
-        assert_eq!(escaped(" \n"), " \\n");
-        assert_eq!(escaped("a\u{1000}v"), "a\\u{1000}v");
-    }
-
     #[test]
     fn basic() {
         let mut f = Function::new();
         assert_eq!(f.to_string(), "function \"\"() {\n}\n");
 
-        f.name.push_str("foo");
+        f.name = FunctionName::new("foo".to_string());
         assert_eq!(f.to_string(), "function foo() {\n}\n");
 
         f.stack_slots.push(StackSlotData::new(4));

cranelift/src/libreader/parser.rs

@@ -470,11 +470,11 @@ impl<'a> Parser<'a> {
     //
     // function ::= "function" * name signature { ... }
     //
-    fn parse_function_name(&mut self) -> Result<String> {
+    fn parse_function_name(&mut self) -> Result<FunctionName> {
         match self.token() {
             Some(Token::Identifier(s)) => {
                 self.consume();
-                Ok(s.to_string())
+                Ok(FunctionName::new(s))
             }
             _ => err!(self.loc, "expected function name"),
         }
@@ -1161,7 +1161,7 @@ mod tests {
                                      }")
             .parse_function()
             .unwrap();
-        assert_eq!(func.name, "foo");
+        assert_eq!(func.name.to_string(), "foo");
         let mut iter = func.stack_slots.keys();
         let ss0 = iter.next().unwrap();
         assert_eq!(ss0.to_string(), "ss0");
@@ -1190,7 +1190,7 @@ mod tests {
                                      }")
             .parse_function()
             .unwrap();
-        assert_eq!(func.name, "ebbs");
+        assert_eq!(func.name.to_string(), "ebbs");
 
         let mut ebbs = func.layout.ebbs();
 
@@ -1219,7 +1219,7 @@ mod tests {
                          ; More trailing.")
                 .parse_function()
                 .unwrap();
-        assert_eq!(&func.name, "comment");
+        assert_eq!(func.name.to_string(), "comment");
         assert_eq!(comments.len(), 8); // no 'before' comment.
         assert_eq!(comments[0],
                    Comment {
@@ -1252,6 +1252,6 @@ mod tests {
         assert_eq!(tf.commands[0].command, "cfg");
         assert_eq!(tf.commands[1].command, "verify");
         assert_eq!(tf.functions.len(), 1);
-        assert_eq!(tf.functions[0].0.name, "comment");
+        assert_eq!(tf.functions[0].0.name.to_string(), "comment");
     }
 }