Linux fastdebug build with debug info

[David Holmes - Sun Microsystems]

Hi Volker,

Compare -g with -gstabs. With a particular VM version is see 146MB vs 
24MB for the debug library.

We use -g for the 64-bit VM by default, but not for 32-bit.

Based on those figures oyu gave it looks like we build with debugging 
info at the gcc-level for the product libs as well.

Anyway seems like something that should be settable externally as the 
builder chooses.

Cheers,
David Holmes

Volker Simonis said the following on 05/25/09 21:07:
> On 5/21/09, Erik Trimble <Erik.Trimble at sun.com> wrote:
>> David Holmes - Sun Microsystems wrote:
>>
>>> Hiroshi Yamauchi said the following on 05/21/09 03:58:
>>>
>>>> Nice talking to you after a while!
>>>>
>>> Likewise! Small world :)
>>>
>>>
>>>> Is there a history about the Linux fastdebug build not having -g or
>> -gstabs?
>>> The history is that it's never been present and no-one seems to have
>> noticed/complained! :) The Solaris fastdebug.make was modified way back in
>> mid 2000.
>>> I've filed: 6843665 in our internal bug system.
>>>
>>> David
>>>
>>  I'm not 100% sure of the difference between our 'fastdebug' and out 'debug'
>> builds, but one thing I do know:  Linux_x64-debug isn't currently done due
>> to _really_ excessive size on the symbol tables and associated output
>> libary.  IIRC, libjvm.so ends up being 1GB+ in size if we do a 'debug' build
>> on linux 64-bit (this was particularly noticable on IA64 [itanium], but is
>> also pronounced on x86_64).
>>
> 
> I think these are really old numbers. Building the Java 6 server VM
> with gcc 4.1 on Linux results in the following sizes of libjvm.so for
> us:
> 
> i386
> -----
> FASTDEBUG with -g -O3 : 141M
> PRODUCT with -g -O3: 182M
> 
> amd64
> ---------
> FASTDEBUG with -g -O3 : 153M
> PRODUCT with -g -O3: 192M
> 
> ia64
> ------
> FASTDEBUG with -g -O3 : 224M
> PRODUCT with -g -O3: 262M
> 
> I can only guess that the PRODUCT builds are bigger because of the
> excessive inlineing with O3.
> 
> I also think the comments in the Makefile which recommend the usage of
> "-gstabs" are very old and outdated by newer versions of gcc. Using
> "-g" for a fastdebug build should be ok and the default from my point
> of view.
> 
> Regards,
> Volker
> 
> 
>>  This may or may not have anything to do with the lack of -g being present
>> in the makefiles. But, I thought you should know.
>>
>>  --
>>  Erik Trimble
>>  Java System Support
>>  Mailstop:  usca22-123
>>  Phone:  x17195
>>  Santa Clara, CA
>>  Timezone: US/Pacific (GMT-0800)
>>
>>