"os" - make this a real namespace?

[Lindenmaier, Goetz]

Hi,

remember that the ugly include cascades are gone, as there is now macro
  #include OS_CPU_HEADER(thread)
including files like thread_linux_x86.hpp.

Therefore I think the need to rename files is no more that
Important.

Best regards,
  Goetz.


> -----Original Message-----
> From: hotspot-runtime-dev [mailto:hotspot-runtime-dev-
> bounces at openjdk.java.net] On Behalf Of Rickard Bäckman
> Sent: Freitag, 21. Oktober 2016 08:02
> To: Thomas Stüfe <thomas.stuefe at gmail.com>
> Cc: hotspot-runtime-dev at openjdk.java.net
> Subject: Re: "os" - make this a real namespace?
> 
> Yes the naming was just one try. There were multiple other ways of doing
> it. Other possibilities were keeping it as is, have one file named
> os_thread.hpp per platform that includes the os_thread_x86.hpp and just
> have the #include "os_thread.hpp" in files that need it... Macros
> *shudder*.
> 
> /R
> 
> On 10/20, Thomas Stüfe wrote:
> > Hi Rickard,
> >
> > I definitely like some of the aspects of that patch. But like others I'm
> > not a big fan of renaming the files - I like the current naming scheme
> > <os>_<cpu> just fine, I am used to it and it helps me in many places. I
> > work both in IDEs (CDT) and on the command line with vi and grep, and
> > having the platform in the file name makes it a easier to work with
> > multiple platforms. I am also quite sure that having different versions of
> > a file with the same name in some locations would bite us at some places.
> >
> > Kind Regards, Thomas
> >
> >
> > On Thu, Oct 20, 2016 at 10:27 AM, Rickard Bäckman <
> > rickard.backman at oracle.com> wrote:
> >
> > > Hi Thomas,
> > >
> > > I tried something like that a couple of years ago and still think it is
> > > a good idea.
> > >
> > > Link to the discussion and patches:
> > >
> > > http://mail.openjdk.java.net/pipermail/hotspot-dev/2013-
> March/008884.html
> > >
> > > /R
> > >
> > > On 10/19, Thomas Stüfe wrote:
> > > > Hi all,
> > > >
> > > > a small question.
> > > >
> > > > I sometimes stumble over the fact that "os" is a class, not a namespace.
> > > > And that we include the platform dependent additions into the middle
> of
> > > > this class.
> > > >
> > > > This has a number of repercussions, like not being able to include the
> > > > platform dependent files (os_<os>_<cpu>) directly, not being able to
> > > > forward declare functions from the "os" namespace (e.g. os::malloc)
> etc.
> > > I
> > > > also cannot split implementations from "os" functions to different
> > > > implementation files without problems.
> > > >
> > > > It seems to me all compiler nowadays support namespaces, would it
> not
> > > make
> > > > sense to convert "os" to a real namespace?
> > > >
> > > > While we are at it, what is the reason for the "<os>" sub classes? e.g.
> > > > os::Bsd, os::Aix etc? It makes integrating patches between platforms
> > > > difficult and, to me, does not seem to serve any clear purpose.
> > > >
> > > > If the purpose is to be a very low wrapper around OS particularities, it
> > > > makes no sense to have them in the "os" namespace and to make
> them
> > > visible
> > > > to the shared sections of the VM. E.g. there should be no reason to
> > > access
> > > > "os::Bsd" functions from outside os/bsd/vm, or to access "os::Posix"
> > > > functions outside implementations specific for Posix platforms.
> > > >
> > > > Thanks, and Kind Regards, Thomas
> > >