[cfe-dev] Distinguishing system headers from user headers using libclang

[Siedlarek, Mikołaj]

On Fri, Apr 12, 2013 at 4:59 PM, Argyrios Kyrtzidis <akyrtzi at gmail.com> wrote:
> On Apr 11, 2013, at 11:43 PM, "Siedlarek, Mikołaj" <m.siedlarek at nctz.net> wrote:
>
>> On Thu, Apr 11, 2013 at 7:22 PM, Argyrios Kyrtzidis <akyrtzi at gmail.com> wrote:
>>> On Apr 5, 2013, at 4:20 AM, "Siedlarek, Mikołaj" <m.siedlarek at nctz.net>
>>> wrote:
>>>
>>> On Fri, Apr 5, 2013 at 12:37 PM, Siedlarek, Mikołaj
>>> <m.siedlarek at nctz.net> wrote:
>>>
>>> On Fri, Apr 5, 2013 at 12:22 AM, Argyrios Kyrtzidis <akyrtzi at gmail.com>
>>> wrote:
>>>
>>>
>>> On Apr 2, 2013, at 1:33 AM, Mikołaj Siedlarek <m.siedlarek at nctz.net> wrote:
>>>
>>> Hi,
>>>
>>> I'm writing a simple code dependency analysis tool using libclang and I'm
>>> missing some way of distinguishing system headers from user headers. I see
>>> clang::DirectoryLookup::getDirCharacteristic() provides such interface, but
>>> is there any way I could obtain this information using just libclang? My
>>> tool is rather simple and I'd like to keep it that way - libclang seems to
>>> be sufficient for the rest of my needs.
>>>
>>>
>>> There is no way currently, but it should relatively easy, are you interested
>>> in providing such a patch ?
>>> The clang function you may need to look into using is
>>> "SourceManager::isInSystemHeader(SourceLocation Loc)"
>>> The libclang function would accept a CXTranslationUnit and a
>>> CXSourceLocation.
>>>
>>>
>>>
>>> How about this? That's the best and most elastic approach I could think of.
>>>
>>>
>>> There was unnecessary CINDEX_LINKAGE in the first version of my patch.
>>> Here's corrected one.
>>>
>>>
>>> +  /**
>>> +   * \brief System code which is implicitly 'extern "C"' in C++ mode
>>> +   */
>>> +  CXCharacteristicKind_ExternCSystem
>>>
>>> This is very "legacy-hacky-compiler-specific"; I can't think of a reason
>>> that a libclang client would need to know this.
>>>
>>> I suggest just adding a
>>> int clang_SourceLocation_isInSystemHeader(CXSourceLocation location)
>>> function.
>>
>> I agree ExternCSystem may not be useful - I added it to mimic
>> underlaying library interface. Nevertheless, I don't think boolean
>> isInSystemHeader is enough. For example - in my program I need to know
>> whether given source location is in user code. !isInSystemHeader
>> wouldn't be enough, because there are also invalid locations like
>> built-in compiler declarations or anything really that has no
>> corresponding location in the source.
>
> To check for invalid locations you can do:
> if (clang_equalLocations(Location, clang_getNullLocation()) {
>   // invalid
> }

I don't really think that's user/client-friendly approach to have a
combination of
different interface functions providing same information type, but I guess it's
your choice. Here's simple isInSystemHeader.

-- 
Mikołaj Siedlarek
m.siedlarek at nctz.net
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