[webkit-dev] Common build system (was Re: WebKit Wishes)

[Dirk Pranke]

On Thu, Jan 31, 2013 at 9:14 AM, Patrick Gansterer <paroga at paroga.com> wrote:
>
> Am 31.01.2013 um 17:17 schrieb Maciej Stachowiak:
>
>
> On Jan 31, 2013, at 1:56 AM, Patrick Gansterer <paroga at paroga.com> wrote:
>
> Am 31.01.2013 um 10:37 schrieb Ryosuke Niwa:
>
> On Thu, Jan 31, 2013 at 1:17 AM, Jochen Eisinger <jochen at chromium.org>
> wrote:
>>
>> Another option is to add a webkit-patch command for modifying the build
>> files. That way, the syntax doesn't need to be overly human friendly. There
>> was also some attempt to write a tool to add files automatically:
>> https://bugs.webkit.org/show_bug.cgi?id=61772  I would expect that such a
>> tool becomes easier if it would only modify one source of truth and
>> generates all other artifacts such as Xcode projects from it.
>
>
> I don't want build file's syntax to be so human unfriendly that I need a
> tool for it.
>
> Often times, these syntax problems can be improved dramatically by simple
> changes. e.g. we had a similar discussion about TestExpectation syntax, and
> I'm much happier with the new syntax even though the new syntax is
> functionally equivalent to the old one, and two syntaxes are very similar.
>
> On Thu, Jan 31, 2013 at 1:17 AM, Mark Rowe <mrowe at apple.com> wrote:
>>
>> I’ve experimented with this in the past and you’re right that it shouldn’t
>> be particularly difficult to do. However, I suspect that the task would be
>> similar in scope to defining an improved syntax for gyp. And if the syntax
>> is the primary sticking point with gyp then it’d seem preferable to tackle
>> initially.
>
>
> Yeah. In fact, we can just come up with whatever syntax we like and convert
> it to the existing gyp format if the syntax was the biggest issue.
>
>
> Do we want to define the whole build system (including information how to
> invoke the generators) with the new system, or is a "simple" list for the
> input files sufficient? IMHO adding a new generator build step happens very
> rarely. So maybe we can spit the "input file list" (mainly *.cpp and *.idl)
> into new files.
> Then GYP and CMake can read them and generate the build system out of them
> directly (like they to already today) instead of listing the files in the
> *.gpyi and *.cmake. This might work for other systems like qmake too.
> For XCode we can maybe have a "template XCode project" and generate the
> "work XCode project" with a script. This script then only need to fill in
> the files from the "input file list" into the "template XCode project".
> Defining the feature flags can be done like Maciej suggested with "Port.h"
> files.
>
>
> I think it would be better to adapt an existing meta build system to our
> needs than to make one from scratch, unless we find that completely
> impractical.
>
> In particular, gyp and cmake both know how to handle generated sources, and
> while it may not be super common to make a new type of generated source,
> it's bad for hackability of the project of doing so is super hard. We get a
> lot of hackability benefits from using various kinds of generated sources,
> many first introduced in the days when we had a lot fewer build systems. So
> in my mind, they are already ahead of a hypothetical "simple" system.
>
>
> Do you want to kick the requirements of the smaller ports from trunk or do
> you think that e.g. a qmake generate for GYP makes sense?
> AFAIK e.g. QtWebKit is shipped with Qt, which uses qmake as build system,
> where CMake/GYP is not an option.
>

It could certainly make sense for us to add Autotools and Qmake
generators to GYP; I'm less certain if a CMake generator makes much
sense, but I haven't thought about it as much. I'm not super familiar
with any of these three tools, so I could be dead wrong.

> I completely agree that creating a new meta meta build system isn't a good
> idea, but sharing the common parts (which reduce the daily productivity)
> might be a step in the right direction. Using simple text files which
> contain the list of files (like the gpyi files already do today) isn't a new
> build system. It only offers the existing meta build systems (CMake, GYP,
> autotools, qmake) to use a common base.
>
> The remaining build systems can be ported to one of these systems or be
> adopted to use this file lists too.
>
> -- Patrick

I suspect that we would quickly find that we would want some sort of
support for conditionals and/or file inclusion in our "simple text
files", at which point you basically get a meta-meta-build system :).
I don't actually think such a thing is that bad of an idea, but it's
all in the details.

I would like to find a solution where all of the ports were able to
retain integration with their "native" build environments one way or
another.

-- Dirk