[PATCH] Some infrastructure work for virtual file system (now on phab)

[Manuel Klimek]

On Wed, Feb 12, 2014 at 11:22 PM, Douglas Gregor <dgregor at apple.com> wrote:

>
> On Feb 12, 2014, at 2:21 PM, Rafael Ávila de Espíndola <
> rafael.espindola at gmail.com> wrote:
>
> >
> >
> > ================
> > Comment at: include/clang/Basic/FileManager.h:122
> > @@ -121,2 +121,3 @@
> > class FileManager : public RefCountedBase<FileManager> {
> > +  IntrusiveRefCntPtr<AbstractFileSystem> FS;
> >   FileSystemOptions FileSystemOpts;
> > ----------------
> > Why is the reference count necessary? Given its nature I would expect
> the FS to outlive the file manger, in which case the FileManager could have
> just a pointer to the FileSystem.
>
>
> The FS is likely to get shared among a number of FileManagers in different
> compiler instances within a thread. Yes, we could try to establish and
> maintain relationships among these, but it’s simpler and costs us
> effectively nothing to make this ref-counted.
>

Just to follow up:
I found one more argument against making this ref-counted:
The constructor of FileManager that uses the default "real" file system is
now actively thread hostile (you cannot create a FileManager per thread
without locking). I think that's rather unexpected.

Cheers,
/Manuel
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20140227/0dfb60e2/attachment.html>