Re: Precompiled headers?

On Tue, Jun 19, 2012 at 7:32 AM, Lubos Lunak <l.lunak@suse.cz> wrote:
>  Hello,
>
>  does somebody know why support for precompiled headers has been removed from
> LibreOffice?
>
>  I couldn't find anything conclusive, repo log messages just say that it's
> being done but not why, in list archives

From memory, the main driver was: bit-rot.
The people that were doing the most work on windows decided that they
were tired to spend a large amount of their time to fix that over and
over again.
No-one stepped up to volunteer to fix the bit-rot and maintain these pch
to a point where people building on windows were actively _not_ using
precompiled header either , to have a chance of finishing a build in
finite time


> [...] PCH with
> MSVC avoid the performance hit of using many -I options (adding -I for each
> <module>/inc adds 25% time for whatever reason, but only without PCH)

ahh, so that is _not_ a myth. Thanks for the data point.

Norbert

PS: what is the perf impact if any on GCC to use the pch include
layout (that is even the pch feature, but over-including headers)
If that overhead is not prohibitive then we could use that way of
doing include _always_... and therefore the pch layout would be
maintained 'naturally'.