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

[Adam Barth]

Ninja has extremely fast incremental builds and can be generated by
GYP.  Here are some stats from a year ago:

https://plus.google.com/101038813433650812235/posts/irc26fhRtPC

Ninja has gotten even faster since then.  If you're interested in
trying it out, you can play around with incremental builds of the
Chromium port on Mac or Linux.

Adam


On Fri, Feb 1, 2013 at 4:58 PM, Balazs Kelemen <kbalazs at webkit.org> wrote:
> I think one important aspect of build systems was not considered yet int
> this conversation: speed. The time an incremental build takes has a great
> effect on developer productivity. I don't think any of the meta-build
> systems we use does a great job here - although I only have experiences with
> qmake, cmake and autotools (and I don't have an SSD that could help
> somewhat).
>
> The technic I found useful here is to avoid calling build-webkit always and
> instead just rebuild the subproject you have edited, so I think it is
> important to have a build system that supports it. Let me share my
> experiences here.
>
> With qmake nowadays this work perfectly. The developer build is producing a
> shared library for every subdir (WTF, JavaScriptCore, WebCore, WebKit2),
> which means you only need to call make in the specific subdirectory (i.e. if
> I only touched WebKit2 files I do "make -C
> WebKitBuild/Release/Source/WebKit2" which is pretty quick). Still WebCore is
> so big that make is quite slowly find out the files you actually edited and
> need to be rebuilt. What could help here is to devide WebCore into smaller
> parts, like the ongoing work of extracting Platform. Maybe the next logical
> candidate could be svg (I don't have real knowledge about how feasible it
> is).
>
> Note that I don't come up with qmake because I would like to recommend it as
> the one and only build system (in fact it has a ridiculously inconvenient
> syntax, and a lot of bugs), just as an example.
>
> With Cmake fast incremental rebuilds are also possible, maybe in a bit more
> complicated way. When working with the EFL port I found a quick rule for
> WebKit2 in the generated makefile. Although the makefiles are usually call
> back to Cmake, and make is not faster than build-webkit, if you use the
> special fast target, which is something like eflWebKit/fast (i.e. make -C
> WebKitBuild/Release/Source/WebKit2 eflWebKit/fast), it will not check
> dependencies but just rebuild the files that have changed. I did not find a
> similar thing for WebCore, I guess because it is not built as a shared
> library.
>
> What I dislike in Cmake is that I am disappointed by how slow a normal
> incremental build with it (i.e. build-webkit). qmake is not faster at all,
> but it generate plain makefiles that typically no call back to qmake if not
> specified explicitly to do so, and directly calling make is faster, yet it
> can handle most of the non-trivial changes, for example editing a generator
> file. I don't know gyp, so I wonder about how would it do in this comparison
> (but I guess it generates simple makefiles as well, so it's similar than
> qmake in this manner.)
>
> I hope I added something to this conversation that is worth to consider with
> my late nightly brain dump.
>
> -kbalazs
>
>
> _______________________________________________
> webkit-dev mailing list
> webkit-dev at lists.webkit.org
> https://lists.webkit.org/mailman/listinfo/webkit-dev

On Fri, Feb 1, 2013 at 4:58 PM, Balazs Kelemen <kbalazs at webkit.org> wrote:
> I think one important aspect of build systems was not considered yet int
> this conversation: speed. The time an incremental build takes has a great
> effect on developer productivity. I don't think any of the meta-build
> systems we use does a great job here - although I only have experiences with
> qmake, cmake and autotools (and I don't have an SSD that could help
> somewhat).
>
> The technic I found useful here is to avoid calling build-webkit always and
> instead just rebuild the subproject you have edited, so I think it is
> important to have a build system that supports it. Let me share my
> experiences here.
>
> With qmake nowadays this work perfectly. The developer build is producing a
> shared library for every subdir (WTF, JavaScriptCore, WebCore, WebKit2),
> which means you only need to call make in the specific subdirectory (i.e. if
> I only touched WebKit2 files I do "make -C
> WebKitBuild/Release/Source/WebKit2" which is pretty quick). Still WebCore is
> so big that make is quite slowly find out the files you actually edited and
> need to be rebuilt. What could help here is to devide WebCore into smaller
> parts, like the ongoing work of extracting Platform. Maybe the next logical
> candidate could be svg (I don't have real knowledge about how feasible it
> is).
>
> Note that I don't come up with qmake because I would like to recommend it as
> the one and only build system (in fact it has a ridiculously inconvenient
> syntax, and a lot of bugs), just as an example.
>
> With Cmake fast incremental rebuilds are also possible, maybe in a bit more
> complicated way. When working with the EFL port I found a quick rule for
> WebKit2 in the generated makefile. Although the makefiles are usually call
> back to Cmake, and make is not faster than build-webkit, if you use the
> special fast target, which is something like eflWebKit/fast (i.e. make -C
> WebKitBuild/Release/Source/WebKit2 eflWebKit/fast), it will not check
> dependencies but just rebuild the files that have changed. I did not find a
> similar thing for WebCore, I guess because it is not built as a shared
> library.
>
> What I dislike in Cmake is that I am disappointed by how slow a normal
> incremental build with it (i.e. build-webkit). qmake is not faster at all,
> but it generate plain makefiles that typically no call back to qmake if not
> specified explicitly to do so, and directly calling make is faster, yet it
> can handle most of the non-trivial changes, for example editing a generator
> file. I don't know gyp, so I wonder about how would it do in this comparison
> (but I guess it generates simple makefiles as well, so it's similar than
> qmake in this manner.)
>
> I hope I added something to this conversation that is worth to consider with
> my late nightly brain dump.
>
> -kbalazs
>
>
> _______________________________________________
> webkit-dev mailing list
> webkit-dev at lists.webkit.org
> https://lists.webkit.org/mailman/listinfo/webkit-dev