Add workaround for archive reading bug in LLDB.

LLDB contains a bug that makes it crash if an archive it reads
contains a file the name of which is exactly 16 bytes long. This
bug recently has made it impossible to debug Rust applications with
LLDB because some standard libraries triggered it indirectly:
For rlibs, rustc includes the LLVM bytecode in the archive, giving
it the extension ".bc.deflate". For liballoc (for example) this
results in the 16 character filename "alloc.bc.deflate", which is
bad.

This commit replaces the ".bc.deflate" suffix with
".bytecode.deflate" which itself is already longer than 16 bytes,
thus making sure that the bug won't be run into anymore.

The bug could still be run into with 14 character filenames because
then the .o files will trigger it. However, this is much more rare
and working around it would introduce more complexity than necessary
at the moment. It can always be done later on, if the need arises.

Fixes #14356.

diff --git a/src/librustc/back/archive.rs b/src/librustc/back/archive.rs
index 0b6540640b4cf60e8f6bd06c696bf474f756957d..edb0a538a03dcdf8b8b42b85108429bb2acd487a 100644 (file)
--- a/src/librustc/back/archive.rs
+++ b/src/librustc/back/archive.rs
@@ -109,7 +109,7 @@ pub fn add_native_library(&mut self, name: &str) -> io::IoResult<()> {
     pub fn add_rlib(&mut self, rlib: &Path, name: &str,
                     lto: bool) -> io::IoResult<()> {
         let object = format!("{}.o", name);
-        let bytecode = format!("{}.bc.deflate", name);
+        let bytecode = format!("{}.bytecode.deflate", name);
         let mut ignore = vec!(bytecode.as_slice(), METADATA_FILENAME);
         if lto {
             ignore.push(object.as_slice());

diff --git a/src/librustc/back/link.rs b/src/librustc/back/link.rs
index 546182aac34e2f5a817dd40b72e7be2ca2999f1f..b432034b81b5625f83a7ce8dfe84f6f8d7812fde 100644 (file)
--- a/src/librustc/back/link.rs
+++ b/src/librustc/back/link.rs
@@ -958,8 +958,12 @@ 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.
             let bc = obj_filename.with_extension("bc");
-            let bc_deflated = obj_filename.with_extension("bc.deflate");
+            let bc_deflated = obj_filename.with_extension("bytecode.deflate");
             match fs::File::open(&bc).read_to_end().and_then(|data| {
                 fs::File::create(&bc_deflated)
                     .write(match flate::deflate_bytes(data.as_slice()) {

diff --git a/src/librustc/back/lto.rs b/src/librustc/back/lto.rs
index 09dfc918967956913af0a122d7b118fd3fae41a8..7449622366fc2678f4c7912ef4e05664c2916562 100644 (file)
--- a/src/librustc/back/lto.rs
+++ b/src/librustc/back/lto.rs
@@ -55,10 +55,10 @@ pub fn run(sess: &session::Session, llmod: ModuleRef,
         let archive = ArchiveRO::open(&path).expect("wanted an rlib");
         debug!("reading {}", name);
         let bc = time(sess.time_passes(),
-                      format!("read {}.bc.deflate", name).as_slice(),
+                      format!("read {}.bytecode.deflate", name).as_slice(),
                       (),
                       |_| {
-                          archive.read(format!("{}.bc.deflate",
+                          archive.read(format!("{}.bytecode.deflate",
                                                name).as_slice())
                       });
         let bc = bc.expect("missing compressed bytecode in archive!");