Stop using precompiled headers for Linux?

[Aleksey Shipilev]

On 10/30/2018 06:26 PM, Ioi Lam wrote:
> Is there any advantage of using precompiled headers on Linux? 

I have measured it recently on shenandoah repositories, and fastdebug/release build times have not
improved with or without PCH. Actually, it gets worse when you touch a single header that is in PCH
list, and you end up recompiling the entire Hotspot. I would be in favor of disabling it by default.

> It's on by default and we keep having
> breakage where someone would forget to add #include. The latest instance is JDK-8213148.

Yes, we catch most of these breakages in CIs. Which tells me adding it to jdk-submit would cover
most of the breakage during pre-integration testing.

-Aleksey