Request for review (S) 6588413: Use -fvisibility=hidden for gcc compiles

[Coleen Phillimore]

On 1/24/2011 2:58 PM, Dmitry Samersoff wrote:
> Coleen,
>
> 1.
> src/cpu/x86/vm/jni_x86.h
>
> JNIIMPORT,JNIEXPORT, JNICALL will not be defined under Win32 is it 
> intended?
It is defined, just later on in the file.  This code is under ifdef 
solaris && linux.
>
> 2. It may make sence to define JNIEXPORT_C  extern "C" JNIEXPORT
The callers usually declare with extern "C" if they want C linkage.  I 
didn't want to change that.

thanks,
Coleen
>
> -Dmitry
>
>
> On 2011-01-24 22:15, Coleen Phillimore wrote:
>> Summary: Add option for gcc 4 and above, define JNIEXPORT and JNIIMPORT
>>
>> open webrev at http://cr.openjdk.java.net/~coleenp/6588413_2/
>>
>> This is an update to the code review. I found symbols that we should
>> have exported. I also found exported symbols that were old and unused
>> and removed them. Embedded question for Igor.
>>
>> Tested with some SA tests and others.
>>
>> Coleen
>>
>> On 1/21/2011 3:39 PM, Coleen Phillimore wrote:
>>> On 1/21/2011 12:47 PM, Dmitry Samersoff wrote:
>>>> Coleen,
>>>>
>>>> 1. Hotspot uses a mapfile to hide unused symbols -
>>>> could we just change the mapfile?
>>> Thanks Dmitry for this question because it prompted me to do more
>>> searching and there were some definitions that should have JNIEXPORT
>>> on them in the VM (AsyncGetCallTrace would have been broken!). The
>>> option -fvisibility=hidden does more than hide the symbols as the
>>> mapfile does, it also allows the compiler to optimize the address
>>> calculations for internal functions it calls. I believe that is where
>>> we get our performance improvements.
>>>>
>>>> 2. JNICALL is empty in both parts of #ifdef.
>>>
>>> Thanks, I fixed that.
>>>
>>> Coleen
>>>>
>>>> -Dmitry
>>>>
>>>>
>>>> On 2011-01-21 19:57, Coleen Phillimore wrote:
>>>>> Summary: Add option for gcc 4 and above, define JNIEXPORT and 
>>>>> JNIIMPORT
>>>>> to visibility=default, add for jio_snprintf and others since
>>>>> -fvisibility=hidden overrides --version-script definitions.
>>>>>
>>>>> Performance increases measured by Volker and Tom;
>>>>>
>>>>> 5% (JBB2005) and 2% (JVM98) on Linux/IA64 and 1,5% (JBB2005) and
>>>>> 0,5% (JVM98) on Linux/PPC64
>>>>>
>>>>>
>>>>> on intel hardware:
>>>>>
>>>>> specjvm98 15 314.61 0.00 0.33 0.006 Yes
>>>>> javac 15 248.88 0.01 1.72 0.000 Yes
>>>>> jack 15 294.44 0.01 1.38 0.000 Yes
>>>>>
>>>>>
>>>>> open webrev at http://cr.openjdk.java.net/~coleenp/6588413/
>>>>> bug link at http://bugs.sun.com/view_bug.do?bug_id=6588413
>>>>>
>>>>> Tested with jmap for any serviceability impact, and tested 
>>>>> hs_err_file
>>>>> decoding still works.
>>>>>
>>>>> Thanks,
>>>>> Coleen
>>>>>
>>>>
>>>>
>>>
>>
>
>