RFR(M): 8019973: PPC64 (part 11): Fix IA64 preprocessor conditionals on AIX.

[Lindenmaier, Goetz]

Hi David,

> A curious thing to do ;-)
Yes, I agree.

> Aside: presumably this is included in turn by other standard headers, 
> not directly included - otherwise we could just undef IA64 after the 
> include.
Yes, that's the case.

> Might be simpler if we just eradicate the IA64 remnants in the code. I 
> think we may even have a RFE for this. AFAIK there are no remaining 
> users of the IA64 code in the hotspot codebase.
Yes, there is a remaining user.  We have Java 4-7 VMs on linux, hp & win
Ia64.  8 in development, all soon based on hs25. We also contributed to 
the change cleaning up the IA64 defines.  There are only such left
we need in our code.
http://hg.openjdk.java.net/hsx/hotspot-main/hotspot/rev/9fae07c31641

> #if defined(__GNUC__) && !defined(IA64)
You are right, I could just leave it as is, except if __GNUC__ is define on AIX, 
who knows ;).  If we don't remove it, I need to add !PPC64 so that it's
inlined in our port on linux.
> more to avoid build-failures, but we may still want to avoid inlining 
> them for other reasons! So this aspect needs further investigation. Or
I think it's a good idea to clean it up.  The build problem 
is documented.  There may be 'other reasons', but unexpected issues 
can be there with any change.

> > prims/forte.cpp uses a lot of different mechanisms all disabling forte
> Again if we just get rid of IA64 this will be a non-issue right?
Here I would add !AIX.
But have a look at the file, there are also several other platforms
where this is excluded, and the exclusion is implemented differently
on each platform.  Not that nice ...

Anyways, I'm fine with adding !AIX/!PPC64 everywhere -- it's nothing
functional.

Best regards,
  Goetz.



-----Original Message-----
From: David Holmes [mailto:david.holmes at oracle.com] 
Sent: Dienstag, 9. Juli 2013 03:56
To: Lindenmaier, Goetz
Cc: ppc-aix-port-dev at openjdk.java.net; 'hotspot-dev at openjdk.java.net'; Vladimir Kozlov
Subject: Re: RFR(M): 8019973: PPC64 (part 11): Fix IA64 preprocessor conditionals on AIX.

Hi Goetz,

On 8/07/2013 10:45 PM, Lindenmaier, Goetz wrote:
> Hi,
>
> This is in preparation of the PPC AIX port.
>
> A header file (systemcfg.h) on Aix 7.1 defines the macro "IA64" unconditionally.

A curious thing to do ;-)

Aside: presumably this is included in turn by other standard headers, 
not directly included - otherwise we could just undef IA64 after the 
include.

> This leads to wrong configurations of shared files on Aix where IA64 is used.
> This change replaces uses of "IA64" by "IA64 && !AIX".

Might be simpler if we just eradicate the IA64 remnants in the code. I 
think we may even have a RFE for this. AFAIK there are no remaining 
users of the IA64 code in the hotspot codebase.

> To reduce the complexity we propose to simplify two matters:
>
> Since the initial checkin objectMonitor.cpp and synchronizer.cpp
> define  #define ATTR __attribute__((noinline)) claiming this is needed
> to avoid a gcc build time error with - at that time - old gcc versions.
> This define depends on IA64. We remove it altogether.

Well it doesn't "depend" on IA64:

#if defined(__GNUC__) && !defined(IA64)
   // Need to inhibit inlining for older versions of GCC to avoid 
build-time failures
   #define ATTR __attribute__((noinline))
#else
   #define ATTR
#endif

it becomes empty on IA64 (and non gcc systems). So removing it 
altogether is changing things for all the other gcc using platforms. Now 
it may be that we don't need to preclude inlining of these methods any 
more to avoid build-failures, but we may still want to avoid inlining 
them for other reasons! So this aspect needs further investigation. Or 
you can just leave it as-is - if you have IA64 always defined then you 
will get the empty #else part. Or if we go with the "eradicate IA64" 
path then you can change IA64 to AIX (though it is odd to exchange an 
architecture check with an OS check).

> prims/forte.cpp uses a lot of different mechanisms all disabling forte
> support on windows, apple and ia64. We would have to add Aix.
> Instead, we propose to use a check for the supported platforms (see webrev).
> We could also add a macro SUPPORTS_FORTE that is defined in the corresponding
> makefiles, and/or move forte.cpp into the os/solaris and os_cpu/linux_x86
> directories.

Again if we just get rid of IA64 this will be a non-issue right?

Thanks,
David

> Are there other platforms that need to be supported? I derived the platforms
> from the comment in forte.cpp.
>
> Please review this change. I'm happy to incorporate your comments.
> http://cr.openjdk.java.net/~goetz/webrevs/8019973-ia64_def/aixia64-hotspot.changeset
>
> Best regards,
>    Goetz.
>