[cfe-dev] AST matchers and thread safety

[Manuel Klimek]

If you have a large code base, I'd suggest to parallelize per translation
unit. Why do you think further parallelizing in-process would help?

If you're concerned about the intermediate file format, I think that in
most cases I've seen the data is simple enough that it will beat the cost
of a correct multi-threaded implementation of anything by far...

Cheers,
/Manuel



On Tue, Sep 24, 2013 at 11:28 AM, Jesper Eskilson
<jesper.eskilson at iar.com>wrote:

> On 09/24/2013 10:41 AM, Gabor Kozar wrote:
>
>> Hi,
>> Since the AST should be immutable once created, and AST matchers are only
>> a high-level wrapper for RecursiveASTVisitor, so I'd expect no problems
>> with multithreading. This definitely needs to be confirmed though by
>> someone who actually knows what they are talking about. :)
>> Just out of curiosity, what is your use case? Navigating the AST is fast,
>> especially compared to the cost of building the AST. Are you running a huge
>> number of matchers?
>>
>
> I have a legacy C++ code base which I'm trying to extract useful
> information out of. For example, a single matcher which matches all method
> definitions of a particular class takes around 8 seconds on my machine,
> varying a little with the complexity of the matcher.
>
> Is the AST kept around for the lifetime of the "ClangTool" object, or is
> it recreated each time the "run" method is invoked? Some of my matchers
> depend on information gathered by other matchers  (one matcher gathers
> method definitions so they can be consumed by when matching the
> corresponding class declarations). For example:
>
> MatchCallback cb1, cb2;
> MatchFinder finder1
>
> finder1.addMatcher(m1, &cb1);
> finder1.addMatcher(m2, &cb2);
>
> tool->run(**newFrontendActionFactory(&**finder1));
>
> MatchCallback cb3, cb4;
> MatchFinder finder2
>
> finder2.addMatcher(m3, &cb3);
> finder2.addMatcher(m4, &cb4);
>
> tool->run(**newFrontendActionFactory(&**finder2));
>
> Will this build the AST twice or just once?  Is there any guarantee
> concerning the order in which the matcher callbacks are invoked?
>
>  --
>> Gábor Kozár -- ShdNx
>> kozargabor at gmail.com
>> On Tue, Sep 24, 2013, at 10:15, Jesper Eskilson wrote:
>>
>>> Hi,
>>> Are the AST matchers thread safe? I have a bunch of matchers which I
>>> would like to run in separate threads for performance reasons. Is that
>>> expected to work, or am I overly optimistic?
>>> /Jesper
>>> --
>>> *Jesper Eskilson* /Development Engineer/
>>> IAR Systems AB
>>> Box 23051, Strandbodgatan 1
>>> SE-750 23 Uppsala, SWEDEN
>>> E-mail: jesper.eskilson at iar.com <mailto:jesper.eskilson at iar.**com<jesper.eskilson at iar.com>>
>>> <mailto:jesper.eskilson at iar.**com <jesper.eskilson at iar.com>>
>>>
>>> Website: www.iar.com
>>> <http://www.iar.com> Twitter: www.twitter.com/iarsystems
>>> <http://www.twitter.com/**iarsystems <http://www.twitter.com/iarsystems>
>>> >
>>> ______________________________**___________________
>>> cfe-dev mailing list
>>> cfe-dev at cs.uiuc.edu <mailto:cfe-dev at cs.uiuc.edu>
>>> http://lists.cs.uiuc.edu/**mailman/listinfo/cfe-dev<http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev>
>>>
>>
>
> --
> *Jesper Eskilson* /Development Engineer/
> IAR Systems AB
> Box 23051, Strandbodgatan 1
> SE-750 23 Uppsala, SWEDEN
> E-mail: jesper.eskilson at iar.com <mailto:jesper.eskilson at iar.**com<jesper.eskilson at iar.com>>
> Website: www.iar.com
> <http://www.iar.com> Twitter: www.twitter.com/iarsystems <
> http://www.twitter.com/**iarsystems <http://www.twitter.com/iarsystems>>
> ______________________________**_________________
> cfe-dev mailing list
> cfe-dev at cs.uiuc.edu
> http://lists.cs.uiuc.edu/**mailman/listinfo/cfe-dev<http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-dev/attachments/20130924/20f427f8/attachment.html>