[cfe-dev] compilation database for tooling

[Haojian Wu via cfe-dev]

>
> i have a question about compilation database (CDB). i wrote tools which
> generate CDB. it follows the format what is mentioned in thedocumentation
> <http://clang.llvm.org/docs/JSONCompilationDatabase.html>. my question
> related to the source file. a source file is mentioned two fields for a
> single entry, the 'file' and the 'command' fields. i remember a discussion
> earlier to make the source file to be relative to the directory (for
> portability). but at the same time, i receive complains
> <https://llvm.org/bugs/show_bug.cgi?id=24710> about my tool when it
> generates non absolute paths (in the 'command' field).


The crash bug is a clang-tidy bug, also reported in PR24834, PR26241. And
I'm trying to fix it now, and the patch (http://reviews.llvm.org/D17335) is
under review. You can find the lit test in the patch.

The CDB should support:
> - absolute paths in directory (relative paths there seem to brittle)
> - relative & absolute paths everywhere else


I agree with Manuel. The `directory` in compilation database should be an
absolute path. Maybe we need to update the compilation database document.


On Fri, Feb 19, 2016 at 7:39 AM, Manuel Klimek <klimek at google.com> wrote:

> On Fri, Feb 19, 2016 at 12:58 AM Laszlo Nagy <
> rizsotto.mailinglist at gmail.com> wrote:
>
>> hi guys,
>>
>> would like to come back to this topic... the inconsistency between the
>> compilation database [CDB] implementation and the documentation about the
>> file paths.
>>
>> would like to clarify what is our expectation about CDB file paths. at
>> the same time would like to pin down these as test cases. and fix the
>> implementation when test cases are not passing.
>>
>> so, for the first part: #1 shall CDB portable and allow relative paths?
>> (it means when i generate a CDB and then i move my sources into another
>> directory (with the CDB), tools shall be happy and run as before the move.)
>> #2 shall CDB support mixture of relative paths and absolute paths? (eg.:
>> the `directory` field in CDB use absolute path, while include paths are
>> relative in the `command` field.) #3 shall CDB support absolute paths too?
>> (my guess that's the only supported case at the moment.)
>>
>
> The CDB should support:
> - absolute paths in directory (relative paths there seem to brittle)
> - relative & absolute paths everywhere else
>
>
>> so, for the test cases: i checked the current functional test against
>> CDB. have not found specific test in the `clang-tools-extra` repo, but find
>> a few in `clang` source tree. #4 where test cases shall go? my other
>> questions about `lit`. CDB is a JSON file. using `lit` usually works as
>> adding comment section. JSON does not support comments. (but have seen
>> 'test/Index/skip-parsed-bodies/compile_commands.json' in clang repo that
>> using it.) #5 will such file parsed? and when i'm writing test with
>> absolute paths, i can't wire in the current absolute path into the file.
>> so, thought to use CMake to substitute those values. #6 but then will `lit`
>> find the generated test files in the build dir too? (or just scans the
>> source dir?)
>>
>
> For lit you give it a couple of RUN files at the start of the file anyway.
> In there, you can just strip the comments out to create the actual CDB
> yourself.
>
>
>>
>> thanks,
>> Laszlo
>>
>> On Fri, Feb 5, 2016 at 11:37 PM, Manuel Klimek <klimek at google.com> wrote:
>>
>>> +clang-tidy folks, as this seems to be more of an issue with clang-tidy
>>> than anything else
>>>
>>> On Fri, Feb 5, 2016 at 12:27 PM Laszlo Nagy via cfe-dev <
>>> cfe-dev at lists.llvm.org> wrote:
>>>
>>>> hi Everyone,
>>>>
>>>> i have a question about compilation database (CDB). i wrote tools which
>>>> generate CDB. it follows the format what is mentioned in the
>>>> documentation <http://clang.llvm.org/docs/JSONCompilationDatabase.html>.
>>>> my question related to the source file. a source file is mentioned two
>>>> fields for a single entry, the 'file' and the 'command' fields. i remember
>>>> a discussion earlier to make the source file to be relative to the
>>>> directory (for portability). but at the same time, i receive complains
>>>> <https://llvm.org/bugs/show_bug.cgi?id=24710> about my tool when it
>>>> generates non absolute paths (in the 'command' field).
>>>>
>>>> to make it more fun, the 'directory' field could be also relative or
>>>> absolute (by the documentation). but two years ago, that was the first
>>>> thing i needed to fix (and always use absolute path).
>>>>
>>>> can somebody tell me what is the current status of the file paths in
>>>> CDB? is there any test suite around the CDB reading in the Clang repo? or
>>>> shall i just blindly copy the CMake generated CDBs and ignore the
>>>> documentation?
>>>>
>>>> thanks,
>>>> Laszlo
>>>> _______________________________________________
>>>> cfe-dev mailing list
>>>> cfe-dev at lists.llvm.org
>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>>>>
>>>
>>
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