RFR: 8074895: os::getenv is inadequate
David Holmes
david.holmes at oracle.com
Mon Mar 30 01:39:32 UTC 2015
On 27/03/2015 5:24 PM, Jeremy Manson wrote:
> I hate to see legacy cruft deliberately introduced into the codebase. I
> guess it is too painful to turn it off in a makefile? Stuff ignored by
> compilers in rarely touched code like this tends to turn crufty and
> become confusing, e.g., something I saw a month or two ago:
>
> http://hg.openjdk.java.net/jdk9/dev/hotspot/file/f68d656d1f5e/src/share/vm/oops/instanceKlass.cpp#l784
>
> Referring you to a page in what you have to think about for a second
> before you realize is JVMS v1, which has been obsolete since 2000, and
> is unavailable from the publisher.
But happens to be the version you would find sitting on the bookshelves
of the Oracle VM team members :) A section reference would be better
than a page number, but even they change over time.
> Doing it this way seems fine to me, but I don't know anything about
> suppressing warnings on Windows, so that's not a firm endorsement. Not
> that my non-reviewer endorsement would do you any good.
Okay. Still need a second review - calling Coleen!
I'd really like to get this out of my repo and pushed :)
Thanks,
David
> Jeremy
>
> On Wed, Mar 25, 2015 at 11:41 PM, David Holmes <david.holmes at oracle.com
> <mailto:david.holmes at oracle.com>> wrote:
>
> Okay I managed to fix this with:
>
> --- old/src/share/vm/utilities/__growableArray.hpp 2015-03-26
> 02:34:35.715892476 -0400
> +++ new/src/share/vm/utilities/__growableArray.hpp 2015-03-26
> 02:34:34.663833288 -0400
> @@ -168,6 +168,8 @@
> GrowableArray(int initial_size, bool C_heap = false, MEMFLAGS F
> = mtInternal)
> : GenericGrowableArray(initial___size, 0, C_heap, F) {
> _data = (E*)raw_allocate(sizeof(E));
> +// Needed for Visual Studio 2012 and older
> +#pragma warning(suppress: 4345)
> for (int i = 0; i < _max; i++) ::new ((void*)&_data[i]) E();
> }
>
> @@ -385,6 +387,8 @@
> E* newData = (E*)raw_allocate(sizeof(E));
> int i = 0;
> for ( ; i < _len; i++) ::new ((void*)&newData[i]) E(_data[i]);
> +// Needed for Visual Studio 2012 and older
> +#pragma warning(suppress: 4345)
> for ( ; i < _max; i++) ::new ((void*)&newData[i]) E();
> for (i = 0; i < old_max; i++) _data[i].~E();
> if (on_C_heap() && _data != NULL) {
>
> So unless someone finds this totally objectionable it is what I
> propose to go with. Full webrev at:
>
> http://cr.openjdk.java.net/~__dholmes/8074895/webrev/
> <http://cr.openjdk.java.net/~dholmes/8074895/webrev/>
>
> Thanks,
> David
>
>
> On 25/03/2015 2:24 PM, David Holmes wrote:
>
> On 24/03/2015 2:56 AM, Jeremy Manson wrote:
>
> Thanks, Kim. This is a pretty silly warning to have break
> the build.
> Does anyone have a problem with PODs being default
> initialized? That's
> required by the standard, so if you do, then you are Doing
> It Wrong.
>
> I assume it is pretty easy to turn the warning off. I'd do
> it, but I
> don't have the Windows build-fu necessary. Also, do we
> think it would
> require another bug?
>
>
> Unless someone else can already tell me how I will try to find the
> cycles to either disable the warning in that file (if that
> works) else
> disable it in the build - which will need a new CR I think.
>
> David
>
> I'd hate to have to change my (or any) code for this.
>
> Jeremy
>
> On Mon, Mar 23, 2015 at 8:48 AM, Kim Barrett
> <kim.barrett at oracle.com <mailto:kim.barrett at oracle.com>
> <mailto:kim.barrett at oracle.com
> <mailto:kim.barrett at oracle.com>__>> wrote:
>
> On Mar 23, 2015, at 3:45 AM, David Holmes
> <david.holmes at oracle.com <mailto:david.holmes at oracle.com>
> <mailto:david.holmes at oracle.__com
> <mailto:david.holmes at oracle.com>>> wrote:
> >
> > On 23/03/2015 4:12 PM, David Holmes wrote:
> >> On 21/03/2015 3:32 AM, Jeremy Manson wrote:
> >>> Argh. Yes. Martin told me not to get involved
> with Windows,
> but would
> >>> I listen? Of course not...
> >>>
>
> >>>http://cr.openjdk.java.net/__~jmanson/8074895/webrev.04/
> <http://cr.openjdk.java.net/~jmanson/8074895/webrev.04/>
> >>
> >> Looks okay to me - running a test job now.
> >
> > <sigh> This just isn't meant to be :( It seems that:
> >
> > GrowableArray<JavaVMOption> options(2, true);
> >
> > in arguments.cpp is giving the windows compiler some
> grief:
> >
> >
> C:\jprt\T\P1\071814.daholme\s\__hotspot\src\share\vm\__utilities/growableArray.hpp(__171)
> : error C2220: warning treated as error - no 'object' file
> generated
> >
> C:\jprt\T\P1\071814.daholme\s\__hotspot\src\share\vm\__utilities/growableArray.hpp(__168)
> : while compiling class template member function
> 'GrowableArray<E>::__GrowableArray(int,bool,__MEMFLAGS)'
> > with
> > [
> > E=JavaVMOption
> > ]
> >
> C:\jprt\T\P1\071814.daholme\s\__hotspot\src\share\vm\runtime\__arguments.cpp(3516)
> : see reference to class template instantiation
> 'GrowableArray<E>'
> being compiled
> > with
> > [
> > E=JavaVMOption
> > ]
> >
> C:\jprt\T\P1\071814.daholme\s\__hotspot\src\share\vm\__utilities/growableArray.hpp(__171)
> : warning C4345: behavior change: an object of POD type
> constructed
> with an initializer of the form () will be default-initialized
> >
> C:\jprt\T\P1\071814.daholme\s\__hotspot\src\share\vm\__utilities/growableArray.hpp(__388)
> : warning C4345: behavior change: an object of POD type
> constructed
> with an initializer of the form () will be default-initialized
> >
> C:\jprt\T\P1\071814.daholme\s\__hotspot\src\share\vm\__utilities/growableArray.hpp(__379)
> : while compiling class template member function 'void
> GrowableArray<E>::grow(int)'
> > with
> > [
> > E=JavaVMOption
> > ]
> >
> > I'm guessing it doesn't like the enum as the generic
> arg, but
> don't know why given that it accepts plain int elsewhere. ???
>
> Just suppressing this warning (unconditionally
> everywhere) would
> probably make sense.
>
> Microsoft describes it as an obsolete warning:
>
> https://msdn.microsoft.com/en-__us/library/wewb47ee.aspx
> <https://msdn.microsoft.com/en-us/library/wewb47ee.aspx>
>
> "This warning is obsolete. It is only generated in
> Visual Studio
> 2005 through Visual Studio 2012. It reports a behavior
> change from
> the Visual C++ compiler that shipped in Visual Studio
> .NET when
> initializing a POD (plain old data) object with (); the
> compiler
> default-initializes the object.”
>
> It’s too bad the JDK9 supported build platform for
> Windows is still
> lagging.
>
>
>
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