Stop using precompiled headers for Linux?

[Erik Joelsson]

On 2018-11-03 01:51, Magnus Ihse Bursie wrote:
>
> On 2018-10-30 20:21, Erik Joelsson wrote:
>> Last I checked, it did provide significant build speed improvements 
>> when building just hotspot, but that could need revisiting.
>>
>> We do have verification of --disable-precompiled-headers (in 
>> slowdebug) in builds-tier2 so we normally get notified if this fails. 
>> However, Mach5 has not been running since Friday so this particular 
>> bug wasn't detected automatically. Looking at the bug, it also failed 
>> on Solaris, which would have been caught by tier1 builds.
>
> If we decide to keep precompiled headers on by default, maybe we 
> should add a simple no-PCH verification task in tier1? It only needs 
> to build hotspot, so it should be quick.
>
That is a good point, so sure we can do that. Which debug level would be 
most appropriate for this test, debug or slowdebug? I very much doubt 
it's relevant to run release builds without PCH.

/Erik
> /Magnus
>
>>
>> /Erik
>>
>>
>> On 2018-10-30 10:26, Ioi Lam wrote:
>>> Is there any advantage of using precompiled headers on Linux? It's 
>>> on by default and we keep having breakage where someone would forget 
>>> to add #include. The latest instance is JDK-8213148.
>>>
>>> I just turn on precompiled headers explicitly in all my builds. I 
>>> don't see any difference in build time (at least not significant 
>>> enough for me to bother).
>>>
>>> Should we disable it by default on Linux?
>>>
>>> Thanks
>>>
>>> - Ioi
>>>
>>>
>>
>