[cfe-dev] questions on the LLVM coding standards

[Marshall Clow]

On Nov 16, 2010, at 2:24 PM, Chris Lattner wrote:
> On Nov 15, 2010, at 5:25 PM, Zhanyong Wan (λx.x x) wrote:
>> While reading the LLVM coding standards
>> (http://llvm.org/docs/CodingStandards.html), I have some questions:

[ snip ]

>> 2. It advises to #include as little as possible.  In particular,
>> "Don't do it unless you have to, especially in header files."  And
>> later it says "you can include them either directly or indirectly
>> (through another header file)."  I'm worried that this may lead
>> dependencies on other headers' implementation details.
> 
> Yes, this is a possible issue, but since LLVM is a relatively self-contained ecosystem, any issues that arise from this can be addressed by fixing the clients of the headers.
> 
> This is in direct contrast to the apparent situation at Google, where they prefer "include what you use".  That approach is taken because it is difficult or expensive to find and update all the clients.

I've been playing with libclang, and trying to adapt c-index-test to make an include file tester.

The idea would be twofold:
	1) Generate a "tree" of includes, so you can see the path where file gets included from. The existing code in c-index-test gives a different view, showing where each file is included from.
	2) Some way of detecting "unused" included files, so that they can be removed.

I'm waiting anixously for the video of Craig Silverstein's talk from the developer meeting to see what he's already done.

Is this something that either 
	a) has been done already
or	b) other people would be interested in?

-- Marshall