Parse and write IR in the 'cat' subcommand.

The 'cton-util cat' command parses the given files and writes them out again to
stdout. This has the effect of reformatting and stripping comments.

Fix a writer bug that inverted the blank line before the first EBB.

src/tools/cat.rs

@@ -3,9 +3,13 @@
 //! Read a sequence of Cretonne IL files and print them again to stdout. This has the effect of
 //! normalizing formatting and removing comments.
 
-use CommandResult;
 use std::fs::File;
-use std::io::Read;
+use std::io::{self, Read};
+
+use CommandResult;
+
+use cton_reader::parser::Parser;
+use cretonne::write::write_function;
 
 pub fn run(files: Vec<String>) -> CommandResult {
     for (i, f) in files.into_iter().enumerate() {
@@ -22,7 +26,16 @@ fn cat_one(filename: String) -> CommandResult {
     let mut buffer = String::new();
     try!(file.read_to_string(&mut buffer)
         .map_err(|e| format!("Couldn't read {}: {}", filename, e)));
+    let items = try!(Parser::parse(&buffer).map_err(|e| format!("{}: {}", filename, e)));
+
+    for (idx, func) in items.into_iter().enumerate() {
+        if idx != 0 {
+            println!("");
+        }
+        let stdout = io::stdout();
+        let mut handle = stdout.lock();
+        try!(write_function(&mut handle, &func).map_err(|e| format!("{}: {}", filename, e)));
+    }
 
-    print!("{}", buffer);
     Ok(())
 }