[cfe-dev] questions regarding using addPPCallbacks

[Farzad Sadeghi via cfe-dev]

using CI.getPreprocessor().addCallbacks(...) also gets me the same
error. it says i'm accessing an incomplete type.
I looked at clang-move. I'm using the exact same methods but im still
having problems with forward declaration of Preprocessor. could this
problem be cause by the fact that I'm putting everything in a cpp file
and i have no header?

On 12/8/16, Farzad Sadeghi <thabogre at gmail.com> wrote:
> yes, InclusionDirective is implemented in PPInclusion.
> ok, thank you.
>
> On 12/8/16, Eric Liu <ioeric at google.com> wrote:
>> You could do: CI.getPreprocessor().addCallbacks(...) instead. BTW, have
>> you
>> implemented InclusionDirective in PPInclusion?
>>
>> This is how clang-move handles it:
>> https://github.com/llvm-mirror/clang-tools-extra/blob/master/clang-move/ClangMove.cpp#L401
>>
>> On Thu, Dec 8, 2016 at 12:51 AM Farzad Sadeghi via cfe-dev <
>> cfe-dev at lists.llvm.org> wrote:
>>
>>> Lets say I want to add a PP callback every time the PP runs into an
>>> InclusionDirective.
>>> going through the docs, I find that clang::PPCallbacks has the virtual
>>> member functions for me implement to do just that. So far so good.
>>> Now, how to tell the PP to use my callbacks?
>>> I came across addPPCallbacks in clang::Preprocessor.
>>> The code already has a class that derives from ASTConsumer to add and
>>> run the matchers.
>>> There is also a class that derives from ASTFrontendAction that is
>>> passed to newFrontendActionFactory to create an instance of, to be
>>> passed to a ClangTool instance to run the action.
>>> Now the questions:
>>> Do i need to cerate a new FrontendAction for the PPCallbacks? If yes,
>>> then does that mean that the inputs get lexed and parsed twice?
>>>
>>> There is only one preprocessor instance used for each
>>> frontendaction,right?
>>> So i need to get a hold of that instance and add my PPCallbacks there.
>>> I went through the docs again and found that I could do that with a
>>> clang::CompilerInstace.
>>> Now in my class that derives from ASTFrontendAction, I figured I'm
>>> getting the CompilerInstance, so maybe i can get the preprocessor
>>> there:
>>>   std::unique_ptr<ASTConsumer> CreateASTConsumer(CompilerInstance &CI,
>>> StringRef file) override
>>> {
>>>     Preprocessor &PP = CI.getPreprocessor();
>>>     PP.addCallbacks(std::unique_ptr<PPCallback> PPInclusion)
>>>
>>>     TheRewriter.setSourceMgr(CI.getSourceManager(), CI.getLangOpts());
>>>     return llvm::make_unique<MyASTConsumer>(TheRewriter);
>>>  }
>>>
>>> PPInclusio is the class that derives from clang::PPCallbacks.
>>> But the compiler tells me "error: member access into incomplete type"
>>> which basically means that the Preprocessor i got from
>>> CompilerInstance is a forward declaration.
>>> How can I actually add a preprocessor callback then?
>>>
>>>
>>> --
>>> Farzad Sadeghi
>>> _______________________________________________
>>> cfe-dev mailing list
>>> cfe-dev at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>>>
>>
>
>
> --
> Farzad Sadeghi
>


-- 
Farzad Sadeghi