[cfe-dev] AST Matchers tutorial

[Sean Silva]

> On another discussion thread you mentioned that CMake needed to be compiled
> with an extra flag. I don't happen to know the details beyond what is
> written, since I set up my environment once, two months ago :)
> Would someone be able to list what's necessary and when?

I believe that you need CMake >=2.8.8 for Ninja, and currently need to
build CMake with -DCMAKE_ENABLE_NINJA on Mac (although I think the
bleeding edge version doesn't need this). I still haven't found a
time/place to actually follow all the steps in the tutorial (I've only
read it), but once I do (it might be a while unfortunately), I'll tell
you if anything didn't go well.

> Actually, this really is intended as the start of the loop migration tool
> I've been working on. I didn't just want to dump 3000 lines of code and
> tests in one patch, though this set is far more fine-grained than I would
> use for future patches. That aside, it would make sense for the tutorial to
> live in examples/.

I think that it is perfectly fine to have the code for the tutorial be
in examples/, while the "real tool" would be somewhere else.

--Sean Silva

On Wed, Aug 1, 2012 at 11:07 AM, Sam Panzer <panzer at google.com> wrote:
> I've enabled comments on the Google Doc to help avoid polluting the mailing
> list too much :)
>
> On Tue, Jul 31, 2012 at 8:09 PM, Sean Silva <silvas at purdue.edu> wrote:
>>
>>
>> Thank you for writing this up! :-)
>>
>> A couple things:
>>
>> Since you're assuming zero Clang experience, I think you can leave out
>> the git-svn stuff (since AFAIK that is only relevant for people with
>> commit access). A simpler way to just checkout LLVM/Clang is
>>
>> $ git clone http://llvm.org/git/llvm.git
>> $ cd source/tools
>> $ git clone http://llvm.org/git/clang.git
>>
>> The git-svn checkout stuff that you are doing looks kind of fearsome.
>> It's easier for a newcomer to just use a pure git workflow.
>
>
> Good point! I meant to ask about that.
>
>>
>>
>> Also, you may want to touch on the scenario that a person already has
>> CMake installed. E.g., that it should be a certain version, needs to
>> be compiled with certain flags, etc.
>
>
> On another discussion thread you mentioned that CMake needed to be compiled
> with an extra flag. I don't happen to know the details beyond what is
> written, since I set up my environment once, two months ago :)
> Would someone be able to list what's necessary and when?
>
>>
>>
>> > Ninja dependency resolver.
>>
>> I would call this "Ninja build tool".
>
>
> Done.
>
>>
>> You should probably link to the LLVM commandline library docs
>> <http://llvm.org/docs/CommandLine.html> in the relevant part of the
>> document.
>>
>
> Link added.
>
>>
>> > the loop’s index variable is compared against N - 1
>>
>> generally aren't half-open loops comparing against N, and not N-1? e.g.
>> for (int I = 0, N = 10; I != N; ++I)
>>
>
> Yes, that's correct and actually what the code implements.
>
>>
>>
>> I think that just a little bit more explanation about the use of
>> FoldingSetNodeID in areSameExpr() would be good. (just explain roughly
>> what it does, links to docs, etc)
>
>
> I added a few links, along with what I understood from the FoldingSetNodeID
> and Stmt::Profile() documentation.
>
>>
>>
>> As far as your patch. My gut seems inclined to have this inside the
>> examples/ subdirectory, since the code is really just example code to
>> accompany the tutorial.
>
>
> Actually, this really is intended as the start of the loop migration tool
> I've been working on. I didn't just want to dump 3000 lines of code and
> tests in one patch, though this set is far more fine-grained than I would
> use for future patches. That aside, it would make sense for the tutorial to
> live in examples/.
>
>>
>>
>> That's all for now. Thank you so much for the extensive docs!
>>
>> --Sean.
>>
>> On Tue, Jul 31, 2012 at 6:34 PM, Sam Panzer <panzer at google.com> wrote:
>> > Hello, again!
>> >
>> > As suggested by a few people, I have been writing up my experiences
>> > starting
>> > development on Clang, and specifically working with Clang-based
>> > refactoring
>> > tools. The repository where my loop converter will live doesn't exist
>> > yet,
>> > so I will use the tutorial as a chance to start offering patches for
>> > review
>> > (they can be rebased to other locations later).
>> >
>> > My intention was to begin assuming zero Clang experience and work
>> > towards
>> > building a slightly simplified version of the loop converter through a
>> > series of fully-explained patches to Clang to a unit-tested functional
>> > tool.
>> > Because the Getting Started page is aimed at people who want to use
>> > Clang
>> > rather than develop for it, I began with cloning clang+llvm from the git
>> > mirrors and preparing a cmake+ninja build.
>> >
>> > What I have so far is currently available as a Google Doc here:
>> >
>> > https://docs.google.com/document/d/1oTkVLhCdRJUEH1_LDaQdXqe8-aOqT5GLDL9e4MhoFF8/edit
>> > If enough people think that the tutorial is useful, I can eventually
>> > convert
>> > it to a nicer format (i.e. HTML with prettier code formatting). I expect
>> > to
>> > have made mistakes, especially in the section about obtaining and
>> > building
>> > Clang :)
>> >
>> > Thoughts?
>> > -Sam
>> >
>> > _______________________________________________
>> > cfe-dev mailing list
>> > cfe-dev at cs.uiuc.edu
>> > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
>> >
>
>