On 08/08/2012 02:27 PM, Benjamin Smedberg wrote:
On 8/8/2012 2:09 PM, Nicolas Silva wrote:
Hi dev-platform,
I spent some time looking at include dependencies lately, and I think
it is an area where we can improve our code without too much effort.
Bad include dependencies lead to slower builds.
What kind of evidence do we have for this? Before spending time
tinkering with removing includes, I think we need to understand
whether it's worth it: unless there is a clear and significant
improvement, there are many other things we could be doing which are
probably more valuable. And if there are significant wins to be had,
should we instead be considering using module-wide includes and
precompiled headers?
--BDS
That's the thing, it is hard to measure the impact of bad dependencies
unless you compare the same code with bad and good dependencies (which
would mean spending the time to fix existing code), or have already
experienced it in another project, or even trust what people say on the
internet about this subject.
Right now I think our build times could benefit more from a better build
system than fixing our include dependencies, if you ask me.
what I propose is to pay attention to these details when adding new
code, because it does not take more time to write these things the right
way. With the example of nsRefPtr, I think the problem is that a lot of
people didn't know it was possible to use forward references with ref
pointers.
I have an ugly script that goes through the dependency files generated
by make to collect informations about dependencies. I'll clean it up if
you are interested (and rewrite it in python because I suppose people in
here don't want to deal with D code).
I think it would help even with module-wide includes because most
translation units include headers from several other modules. Here is a
list of the TUs that include 2D.h (as of last Wednesday) on a Linux
debug build: http://pastebin.mozilla.org/1745045
A lot of them have nothing to do with graphics.
Nicolas Silva
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