rustc: Avoid 16-byte filenames in rlibs

In addition to avoiding 16-byte filenames with bytecode files, this commit also
avoids 16-byte filenames with object files pulled in from native libraries.

Author: alexcrichton

src/librustc/back/archive.rs

@@ -166,6 +166,15 @@ impl<'a> Archive<'a> {
             if filename.contains(".SYMDEF") { continue }
 
             let filename = format!("r-{}-{}", name, filename);
+            // LLDB (as mentioned in back::link) crashes on filenames of exactly
+            // 16 bytes in length. If we're including an object file with
+            // exactly 16-bytes of characters, give it some prefix so that it's
+            // not 16 bytes.
+            let filename = if filename.len() == 16 {
+                format!("lldb-fix-{}", filename)
+            } else {
+                filename
+            };
             let new_filename = file.with_filename(filename);
             try!(fs::rename(file, &new_filename));
             inputs.push(new_filename);

src/librustc/back/link.rs

@@ -958,10 +958,11 @@ fn link_rlib<'a>(sess: &'a Session,
 
             // For LTO purposes, the bytecode of this library is also inserted
             // into the archive.
-            // Note that we make sure that the bytecode filename in the archive is always at least
-            // 16 bytes long by adding a 16 byte extension to it. This is to work around a bug in
-            // LLDB that would cause it to crash if the name of a file in an archive was exactly
-            // 16 bytes.
+            //
+            // Note that we make sure that the bytecode filename in the archive
+            // is never exactly 16 bytes long by adding a 16 byte extension to
+            // it. This is to work around a bug in LLDB that would cause it to
+            // crash if the name of a file in an archive was exactly 16 bytes.
             let bc = obj_filename.with_extension("bc");
             let bc_deflated = obj_filename.with_extension("bytecode.deflate");
             match fs::File::open(&bc).read_to_end().and_then(|data| {