[cfe-dev] Source-to-source translation using LibTooling

[TROUVE Antoine]

Le 2013/01/16 à 18:13, Manuel Klimek <klimek at google.com> a écrit :

> On Wed, Jan 16, 2013 at 7:39 AM, Antoine Trouve <trouve at isit.or.jp> wrote:
> Dear,
> 
> Regarding the below topic, I am now trying to convert my tool using the RefactoringTool.
> 
> I am using a RecursiveASTVisitor, but I can't find any way (other than using a global variable) to pass the replacement list to my ASTVisitor.
> Indeed, when I create my RecursiveASTVisitor object (inside ASTFrontendAction.CreateASTConsumer), I only have access to the Compiler object, not the tool object.
> However, the only way I could find to get the replacement list was through RefactoringTool->getReplacements().
> 
> Did I miss something ?
> Is there any way to make my RecursiveASTVisitor aware of the Replacement list ?
> 
> All the examples I could find on the repository use a MatchFinder with a custom callback that is aware of the replacement list.
> Was the RefactoringTool API designed with this very specific use in mind ?
> 
> The Tool/RefactoringTool interface takes a tooling::FrontendActionFactory, so you have two options (we have some convenience methods in Tooling.h around line 66-100):
> 
> struct MyFrontendActionFactory : public FrontendActionFactory {
>   MyFrontendActionFactory(tooling::Replacements* Replaces) : Replaces(Replaces) {}
>   virtual clang::FrontendAction *create() {
>     // Give the replacements to your frontend action and from there to your ASTConsumer
>   }
>   tooling::Replacements* Replaces;
> };
> 
> Now with convenience methods you can also just do (note that you'll need the MyASTConsumer part anyway):
> struct MyASTConsumer : public ASTConsumer {
>   MyASTConsumer(tooling::Replacements* Replaces); // otherwise like above
> };
> // This doesn't need to be an interface, simply having the method newASTConsumer will be enough...
> struct MyConsumerFactory {
>   MyConsumerFactory(tooling::Replacements* Replaces);
>   clang::ASTConsumer *newASTConsumer() { return new MyASTConsumer(Replaces); }
>   tooling::Replacements* Replaces;
> };
> and where you create the RefactoringTool:
> RefactoringTool Tool(...);
> MyConsumerFactory ConsumerFactory(Tool.getReplacements());
> return Tool.runAndSave(newFrontendActionFactory(&ConsumerFactory));
> 
> Note that I didn't write out everything for the first version, as it's more code :) Also, I wrote all that without trying to compile it, so there will be compile errors, but the principle should work…

Thank you so much for your comprehensive answer !
I got a bit lost with all these factories of factories, but it finally works !

- Antoine

> 
> Cheers,
> /Manuel
> 
> 
>  
> 
> Regards,
> 
> - Antoine
> 
> Le H.25/01/10 à 18:33, Antoine Trouve <trouve at isit.or.jp> a écrit :
> 
> >
> > Le H.25/01/10 à 18:25, Manuel Klimek <klimek at google.com> a écrit :
> >
> >> On Thu, Jan 10, 2013 at 10:22 AM, Antoine Trouve <trouve at isit.or.jp> wrote:
> >>
> >> Le H.25/01/10 à 18:03, Manuel Klimek <klimek at google.com> a écrit :
> >>
> >>>> On Thu, Jan 10, 2013 at 8:44 AM, Antoine Trouve <trouve at isit.or.jp> wrote:
> >>>> Hello everybody,
> >>>>
> >>>> I have successfully written a source-to-source translator using LibTooling, and I am now willing to go further and do some source-to-source translation.
> >>>> However, I can't figure out how to output modified code with LibTooling.
> >>>>
> >>>> I have used in the past the class "Rewriter", coupled with a "RewriterBuffer" to do this job, but without the LibTooling (I was manipulating "CompilerInstance" object directly).
> >>>> However, a "RewriterBuffer" requires a file ID (that I used to get from a "SourceManager") to be created, and I don't have access to such information anymore, because I'm calling my tool using "Tool.run" from a custom "FrontEndAction".
> >>>>
> >>>> I've spotted the example called "loop-convert" in the clang-tools-extra repository, that is using class derived from "RefactoringTool" to do source-to-source transformation. I kind of made sense of this code, but the way it works would require me to change my code deeply in order to fill the so-called replacement list.
> >>>>
> >>>> Does someone has any experience on this matter in order to give some advices on the best approach I should adopt ?
> >>>
> >>> I'm not 100% sure what you're looking for - as you said, the RefactoringTool is what's meant to be used to write out changed code - I'm open to changes to that interface if it helps your use case, but I don't know your code, so it's hard for me to tell exactly why that would be a deep change, or how to fit it into your project.
> >>>
> >>> My intuition would be that at the point at which you would make changes vie the Rewriter, you would instead fill the Replacements...
> >>>
> >>> Cheers,
> >>> /Manuel
> >>
> >> Thank you for your answer. Basically I would like to know what is the *standard* way to do source-to-source translation in Libtooling.
> >> Should I understand that this is by using "RefactoringTool" ? Updating my code would require some effort for me to understand how the "Replacements" work, so I want to be sure that this is not to find out that there is a better way to do so.
> >>
> >> To answer your question, I detect "for" statements; analyse the body of the loop to extract some metrics; and add a comment after the for with the values of the previously measured metrics. I used to use the "Rewriting" class to add this comment.
> >>
> >> Ah, yes, RefactoringTool is the intended "standard" way to do source-to-source with libtooling. I think if you already use the Rewriter, I'll expect it to actually be not hard to change to using the Replacements :)
> >>
> >> Cheers,
> >> /Manuel
> >
> > OK. Thank you for you fast answers.
> > I'll convert my code then, and kindly come back to you if I have any issue.
> >
> > Best regards,
> >
> > - Antoine
> >
> >>
> >>
> >> Regards,
> >>
> >> - Antoine
> >>
> >>>> Best regards,
> >>>>
> >>>> - Antoine
> >>>> _______________________________________________
> >>> cfe-dev mailing list
> >>> cfe-dev at cs.uiuc.edu
> >>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
> >>>
> >>
> >>
> >
> 
> 

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