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/libcretonne/write.rs

@@ -16,7 +16,7 @@ pub fn write_function(w: &mut Write, func: &Function) -> Result {
     try!(writeln!(w, " {{"));
     let mut any = try!(write_preamble(w, func));
     for ebb in func.ebbs_numerically() {
-        if !any {
+        if any {
             try!(writeln!(w, ""));
         }
         try!(write_ebb(w, func, ebb));
@@ -209,14 +209,14 @@ mod tests {
 
         let ebb = f.make_ebb();
         assert_eq!(function_to_string(&f),
-                   "function foo() {\n    ss0 = stack_slot 4\nebb0:\n}\n");
+                   "function foo() {\n    ss0 = stack_slot 4\n\nebb0:\n}\n");
 
         f.append_ebb_arg(ebb, types::I8);
         assert_eq!(function_to_string(&f),
-                   "function foo() {\n    ss0 = stack_slot 4\nebb0(vx0: i8):\n}\n");
+                   "function foo() {\n    ss0 = stack_slot 4\n\nebb0(vx0: i8):\n}\n");
 
         f.append_ebb_arg(ebb, types::F32.by(4).unwrap());
         assert_eq!(function_to_string(&f),
-                   "function foo() {\n    ss0 = stack_slot 4\nebb0(vx0: i8, vx1: f32x4):\n}\n");
+                   "function foo() {\n    ss0 = stack_slot 4\n\nebb0(vx0: i8, vx1: f32x4):\n}\n");
     }
 }

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(())
 }