[LLVMdev] GCMetadataPrinter::finishAssembly not executed?

[Pedro Artigas]

Hello Yiannis,

I believe what is going on is that there is an issue with the way that information is deleted (the CG information). Right now there is a pass whose only job is to delete that information (CGInfoDeleter) and that pass deletes the info before the AsmPrinter has a chance to call the finishAssembly function. Right now the order that the doFinalization is called on passes is the reverse order of doInitialization (and that makes sense as if a pass depends on some other pass it has to initialize after that pass and clean up before it) so the deleter pass would have to be added in the pass order after the AsmPrinter pass as that pass clearly depends on the Deleter pass (passes that have dependencies on other passes should finalize before the pass it depends on does).

I have a hunch that the very need for the Deleter pass is that the order of deletion was somewhat undefined before and by having an specific pass one could place the deletion wherever she/he sees fit. Now that the doFinalization order is the reverse of the doInitialization one can probably just not have a deleter and free the info inside the printer pass. The AsmPrinter depends on the Printer pass so the new order should take care of initialization and finalization at the right time.

Does this make sense?

Pedro

On Feb 14, 2013, at 12:04 PM, Yiannis Tsiouris <gtsiour at softlab.ntua.gr> wrote:

> Sorry for the triple-posting! :-$
> 
> On 02/14/2013 04:30 PM, Yiannis Tsiouris wrote:
>> On 02/10/2013 08:47 PM, Yiannis Tsiouris wrote:
>>> After rebasing my local LLVM repo to ToT, I noticed that the
>>> finishAssembly function is not executed and, thus, the stack map is not
>>> printed at all.
>>> 
>>> Is this a known issue or I 'm doing something wrong?
>>> 
>>> I used a custom GCMetadataPrinter plugin but I reproduced this using the
>>> builtin "ocaml" GC plugin and the attached file (actually, any simple ll
>>> file that uses "ocaml" gc is fine).
>>> 
>>> Note: The beginAssembly function works great.
>> I've tried adding two debug prints in lib/CodeGen/AsmPrinter/OcamlGCPrinter.cpp: one in beginAssembly and one in finishAssembly. It seems to me that finishAssembly is never called.
> 
> I used git bisect and I think the commit that is responsible for this is:
> 
> > d1abec365aa89a8497d9b615ccb4b21c72da9447 is the first bad commit
> > commit d1abec365aa89a8497d9b615ccb4b21c72da9447
> > Author: Pedro Artigas <partigas at apple.com>
> > Date:   Wed Dec 5 17:12:22 2012 +0000
> >
> >    - Added calls to doInitialization/doFinalization to immutable passes
> >    - fixed ordering of calls to doFinalization to be the reverse of the pass run order due to potential dependencies
> >    - fixed machine module info to operate in the doInitialization/doFinalization model, also fixes some FIXMEs
> >
> >    reviewed by Evan Cheng <evan.cheng at apple.com>
> >
> >
> >
> >    git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169391 91177308-0d34-0410-b5e6-96231b3b80d8
> 
> Evan or Pedro, can you please take a look at this? :-)
> 
> Thanks!
> yiannis
> 
> -- 
> Yiannis Tsiouris
> Ph.D. student,
> Software Engineering Laboratory,
> National Technical University of Athens
> WWW: http://www.softlab.ntua.gr/~gtsiour
>