Move library crates under 'lib/'.

Give these crates each a more standard directory layout with sources in
a 'src' sub-sirectory and Cargo.toml in the top lib/foo directory.

Add license and description fields to each.

The build script for the cretonne crate now lives in
'lib/cretonne/build.rs' separating it from the normal library sources
under 'lib/cretonne/src'.

lib/cretonne/src/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\"");
+    }
+}