RFR: 8000818: SA constant pool need to reference to reference map after permgen removal

[serguei.spitsyn at oracle.com]

Yumin,

Ok, thanks!
Serguei

On 10/17/12 2:37 PM, Yumin Qi wrote:
> Serguei,
>
>   You are right, here should use 0xffff which is for short.
>   First we got a short from GetBytesXXX function, we assign it to 
> int.  When it is used, only lower 16 bits are used. To prevent it has 
> invalid bits set in upper 16 bits, masking off them.
>   Switch bytes, is for in case the index is a short number stored in 
> method byte code. On X86, bytes needed to be switched to reflect the 
> correct value as java conform.
>
>   Thanks
>   Yumin
>
> On 10/17/2012 1:05 PM, serguei.spitsyn at oracle.com wrote:
>> Hi Yumin,
>>
>> I have a question.
>> ByteCodeRewriter.java:
>> 65 return (short)cpool.objectToCPIndex(refIndex & 0xff);
>>
>>   Why the mask 0xff is used above?  The refIndex can be a short 
>> value, right?
>>   Otherwise, why would you need to swap bytes at the line 62 ? :
>>     62 case 3: refIndex = 
>> bytes.swapShort(method.getBytecodeShortArg(bci)); break;
>>
>> And I agree with David that one of these assignements seems to be 
>> redundant:
>>    58 int refIndex = method.getBytecodeByteArg(bci);
>> 61 case 2: refIndex = method.getBytecodeByteArg(bci); break;
>>
>>
>> Thanks,
>> Serguei
>>
>>
>> On 10/16/12 9:51 PM, Yumin Qi wrote:
>>> Hi, all
>>>
>>>   May I have your codereview on
>>>
>>> http://cr.openjdk.java.net/~minqi/8000818/ 
>>> <http://cr.openjdk.java.net/%7Eminqi/8000818/>
>>>
>>> 8000818: SA constant pool need to reference to reference map after 
>>> permgen removal
>>> Summary: After permgen removal, constant pool changed to put _ldc 
>>> and _ldc_w (fast_ldc and fast_ldcw) index to reference map, no 
>>> longer calculated via constant pool cache.
>>> Also, there is a mistake in 6879063: SA should use hsdis. Bytes.swap 
>>> should only check if the underlying platform is big endian  since 
>>> java code follows big endian.  Revert it back to its orginal form, 
>>> else it will fail  ClassDump.
>>>
>>> Reviewed-by:
>>> Contributed-by: yumin.qi at oracle.com
>>>
>>>
>>> Thanks
>>> Yumin
>>

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