RFR (S): 8003853: specify offset of IC load in java_to_interp stub [Was: Re: RFR (S): Specify offset of IC load in java_to_interp stub.]

[Christian Thalinger]

On Nov 21, 2012, at 12:15 AM, "Lindenmaier, Goetz" <goetz.lindenmaier at sap.com> wrote:

> Hi Chris, 
> 
> yes, there is no C1 on ppc.  
> We do tiered compilation with a stripped C2.

Right.  But some other architecture (or in the future) might need this for C1 as well.  We should find a better place for the value than the ad file.  The obvious place would be compiledIC_<arch>.hpp but we don't have that file, yet.

I filed:

8003853: specify offset of IC load in java_to_interp stub

-- Chris

> 
> Best regards,
>  Goetz
> 
> -----Original Message-----
> From: Christian Thalinger [mailto:christian.thalinger at oracle.com] 
> Sent: Dienstag, 20. November 2012 22:19
> To: Lindenmaier, Goetz
> Cc: hotspot-compiler-dev at openjdk.java.net
> Subject: Re: RFR (S): Specify offset of IC load in java_to_interp stub.
> 
> 
> On Nov 20, 2012, at 3:08 AM, "Lindenmaier, Goetz" <goetz.lindenmaier at sap.com> wrote:
> 
>> Hi,
>> 
>> The class CompiledStaticCall must know the location of the IC load in the java_to_interp stub
>> to update the IC  with NativeMovConstReg.  The current implementation assumes that
>> the load is always the first instruction in the stub.  This is an artificial restriction. E.g.,
>> it might be useful to load the constant pool address (MachConstantBase) before the
>> IC load (as we do on PPC).
>> 
>> This change adds a constant specifying an offset from the beginning of the stub to
>> the  IC load. The offset is platform specific and 0 on sparc and x86.
>> 
>> You can find the change here:
>> http://cr.openjdk.java.net/~goetz/webrevs/webrev-IC_offset/
> 
> That should be fixed indeed.  
> 
> +#ifndef COMPILER2
> +const int CompiledStaticCall::comp_to_int_load_offset = 0;
> 
> There is no C1 for PPC (sorry, I didn't check)?
> 
> -- Chris
> 
>> 
>> or in our ppc port:
>> http://hg.openjdk.java.net/ppc-aix-port/jdk7u/hotspot/rev/c6f9c897ea33
>> 
>> Thank you and best regards,
>>  Goetz
>> 
>> 
>> 
>