RFR (S): 8029888: PPC64: (part 219): smaller changes needed to build c2

Lindenmaier, Goetz goetz.lindenmaier at sap.com
Tue Dec 10 11:47:54 PST 2013

Hi Vladimir,

I just came up with a better idea for this, it even does not need
shared changes.
I figured loadConNKlass is a real constant, i.e., it's not moved or the 
like, right? So I can just check the concrete value whether it's
31 bit only: 
Assembler::is_uimm((jlong)Klass::encode_klass((Klass *)$src$$constant), 31)

I'm just running a test and will remove the respective coding from the 

About the public: I added that before and now remove it again,
as with the fix currently in the webrev it's not needed.

Best regards,

-----Original Message-----
From: Vladimir Kozlov [mailto:vladimir.kozlov at oracle.com] 
Sent: Tuesday, December 10, 2013 5:53 PM
To: Lindenmaier, Goetz; 'hotspot-dev at openjdk.java.net'; 'ppc-aix-port-dev at openjdk.java.net'
Subject: Re: RFR (S): 8029888: PPC64: (part 219): smaller changes needed to build c2


Ther is initialization of compressed class structure:

NarrowPtrStruct is useed for both compressed class ptrs and oops. Can you use separate Universe::_narrow_klass_max_val 
static field instead of including it into NarrowPtrStruct? And you missed initialization.

Do you need changes in metaspace.hpp for some ppc64 code? I don't see "public" usage in current code.


On 12/10/13 6:08 AM, Lindenmaier, Goetz wrote:
> Hi,
> Recent changes make two other smaller shared adaptions necessary
> for the ppc port:
> http://cr.openjdk.java.net/~goetz/webrevs/8029888-0-basic2/
> First, introduce replacement variable $$CondRegister in adl.
> Further, the latest changes to compressed klasses broke an
> optimization on ppc.  This change contains a better way
> to check for the max size of a compressed klass.  I need not mask
> sign extension bits if compressed klasses are at most 31 bits.
> Please review and test this change.
> Best regards,
>    Goetz.

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