RFR (M): Enable HotSpot build with Clang

[Volker Simonis]

On Thu, May 30, 2013 at 8:32 PM, Christian Thalinger <
christian.thalinger at oracle.com> wrote:

>
> On May 30, 2013, at 10:36 AM, Christian Thalinger <
> christian.thalinger at oracle.com> wrote:
>
> >
> > On May 28, 2013, at 11:03 AM, Christian Thalinger <
> christian.thalinger at oracle.com> wrote:
> >
> >>
> >> On May 26, 2013, at 7:42 PM, David Holmes <david.holmes at oracle.com>
> wrote:
> >>
> >>> <trimming>
> >>>
> >>> On 25/05/2013 6:39 PM, Volker Simonis wrote:
> >>>> On Fri, May 24, 2013 at 5:32 PM, Christian Thalinger
> >>>> <christian.thalinger at oracle.com <mailto:
> christian.thalinger at oracle.com>>
> >>>> wrote:
> >>>>  Will you change Linux to also reuse the GCC files and remove these
> >>>>  ifdefs?
> >>>>
> >>>>
> >>>> OK, if you insist so badly :)
> >>>>
> >>>> http://cr.openjdk.java.net/~simonis/webrevs/8015252.v2/
> >>>>
> >>>> I've tried not to change anything in the default gcc build with the
> one
> >>>> exception that i486 will now use '-g' instead of '-gstabs' as well
> which
> >>>> I think should be OK. But you can easily change that if you'd like.
> >>>
> >>> This needs to be changed back. There is a lot of history here and
> these flags tend to oscillate, but before you can change them we need to
> establish exactly what the size impact will be and make sure our build
> systems can cope with the change.
> >>
> >> I'll change it back.  -- Chris
> >
> > Here is what I have after merging in your new changes:
> >
> > http://cr.openjdk.java.net/~twisti/8015252/webrev/
> >
> > I see two problems:
> >
> > 1)  It's not possible to turn off precompiled headers because of this:
> >
> > + ifeq ($(USE_CLANG), true)
> > +   # clang has precompiled headers support by default, but the user can
> switch
> > +   # it off by using 'USE_PRECOMPILED_HEADER=0' on the compile command
> line.
> > +   ifdef LP64
> > +     USE_PRECOMPILED_HEADER=1
> > +   else
>
> Let me rephrase that:  at least not with an environment variable.
>


Yes, but you can use 'make ... USE_PRECOMPILED_HEADER=0' and that's what I
meant in the comment which should actually read "..on the make command
line.." as David pointed out correctly. This is the usual 'make'-way of
overriding variables:
http://www.gnu.org/software/make/manual/html_node/Overriding.html#Overriding



>
> -- Chris
>
> >
> > 2)  If I compile with clang on Mac and run the compiler regression tests
> a lot of them fail but they work with a debug VM.  So it seems that one of
> the files is broken with optimization on (-Os or -O3; -O0 is okay).
> >
> > Do you have any problems on Linux?
> >
> > -- Chris
> >
> >>
> >>>
> >>> David
> >>> -----
> >>>
> >>>> Please notice that I won't be in the office until the 3rd of June.
> >>>> Should you have any further change requests please feel free to edit
> the
> >>>> patch yourself if you like.
> >>>>
> >>>> Regards,
> >>>> Volker
> >>>>
> >>>>  -- Chris
> >>>>
> >>>>>      -- Chris
> >>>>>
> >>>>>>
> >>>>>>
> >>>>>>> But you can say the exact same thing about the Solaris
> >>>>>>          gcc support.
> >>>>>>
> >>>>>>          Btw. I just trying to resurrect this.
> >>>>>>
> >>>>>>          -- Chris
> >>>>>>
> >>>>>>>
> >>>>>>> David
> >>>>>>> -----
> >>>>>>>
> >>>>>>>> Once it's in we could start with the JDK forest and
> >>>>>>          the configure part
> >>>>>>>> in the base repository. That would require two extra
> >>>>>>          change sets anyway.
> >>>>>>>> The HotSpot build currently isn't very
> >>>>>>          configure-agnostic anyway and
> >>>>>>>> once the other parts have been completed, configure
> >>>>>>          could just pass
> >>>>>>>> USE_CLANG=true (plus perhaps some extra variables in
> >>>>>>          the case we have
> >>>>>>>> more than one clang version on the system) to the
> >>>>>>          HotSpot build and
> >>>>>>>> everything should work.
> >>>>>>>> As a last step we would have to test on Mac as well.
> >>>>>>          I currently don't
> >>>>>>>> have one at hand, but sponsors are always welcome:)
> >>>>>>>>
> >>>>>>>> Volker
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>  David H.
> >>>>>>>>
> >>>>>>>>      -- Chris
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>          David
> >>>>>>>>
> >>>>>>>>
> >>>>>>
> >>>>>>
> >>>>>
> >>>>>
> >>>>
> >>>>
> >>
> >
>
>
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