[llvm-dev] MIR YAML deserialisation failure

[Nemanja Ivanovic via llvm-dev]

I'm not sure if this helps, but here it is in case it does.

I typically use bugpoint in a way as to keep the actual failure that I'm
after. For example, with the test case you've pasted, I was looking for a
specific assert. So I used bugpoint this way:

$ cat reduceme.sh
#!/bin/bash
llc -filetype=obj $1 2>&1 | grep 'Cannot lower calls with arbitrary operand
bundles'
RC=$?
if [[ $RC -eq 0 ]]
then
  exit 1
fi
exit 0

$ bugpoint -compile-custom -compile-command=$PWD/reduceme.sh input.ll

That will ensure that bugpoint retains the specific desired failure
behaviour as it is reducing the test case.

Hope that helps,
Nemanja

P.S. It is not that I am specifically interested in that assert - just that
that's how the original test case was failing so that's what I wanted to
preserve as an illustration.

On Tue, Mar 20, 2018 at 11:14 AM, Valentin Churavy <v.churavy at gmail.com>
wrote:

> Thank you both!
>
> I was running into the issue that bugpoint was reducing my test-case into
> other failures and I hadn't managed yet to find the right point in the
> Julia pass pipeline to insert the module to reproduce the issue reliably
> from llc and that's why I started looking at using the MIR.
>
> I will go back at looking at the pass pipeline and the IR and get a
> reproducer that way!
>
> Thanks,
> Valentin
>
> On Tue, 20 Mar 2018 at 07:51 Nemanja Ivanovic <nemanja.i.ibm at gmail.com>
> wrote:
>
>> Valentin,
>> in terms of limitations as Sean pointed out, an important one is that
>> .mir doesn't have MachineFunctionInfo which may result in failure on
>> accesses to global variables due to use of register X2. The verifier
>> considers it an undefined register.
>> Also, it's probably easier to reduce test cases using bugpoint starting
>> from an IR test case. With the code you provided, I get a different crash
>> than what you apparently get. Here are the test case and the backtrace.
>>
>> Test case: https://pastebin.com/fxjRtJD0
>> Backtrace: https://pastebin.com/FsXMvbGK
>>
>> Nemanja
>>
>> On Mon, Mar 19, 2018 at 11:51 PM, Sean Fertile via llvm-dev <
>> llvm-dev at lists.llvm.org> wrote:
>>
>>> Hello Valentin,
>>>
>>> To generate a mir test case i think the process is to first create an IR
>>> file by passing '-S -emit-llvm' to clang, then you can feed that file into
>>> llc and use stop-before to get the mir just before the if-converter pass,
>>> eg: `llc -stop-before=if-converter  -simplify-mir -o test.mir test.ll`.
>>>
>>> Also there is a MIR language reference: https://llvm.org/docs/
>>> MIRLangRef.html which has some of the limitations documented, as well
>>> as tips for further simplifying the generated mir if need be.
>>>
>>> Regards,
>>> Sean
>>>
>>> On Mon, Mar 19, 2018 at 7:53 PM, Valentin Churavy via llvm-dev <
>>> llvm-dev at lists.llvm.org> wrote:
>>>
>>>> Hello,
>>>>
>>>> I am trying to isolate an assertion failure in if-converter (on PPC)
>>>> and I generated a textual debuglog with:
>>>>
>>>> ```
>>>> LLVM_ARGS=-print-before-all -print-module-scope
>>>> -filter-print-funcs=japi1__require_7687
>>>> ```
>>>>
>>>> and after splicing out the the MIR before the if-converter pass
>>>> I would like to run `llc -march=ppc64le -run-pass=if-converter
>>>> input.mir` so that I can start minimising the MIR.
>>>>
>>>> This steps fails for me with a:
>>>> ```
>>>> error: YAML:188:20: Unrecognized character while tokenizing.
>>>> Function Live Ins: %x4
>>>>                    ^
>>>>
>>>> error: YAML:188:1: Map value must not be empty
>>>> Function Live Ins: %x4
>>>> ^~~~~~~~~~~~~~~~~
>>>> ```
>>>>
>>>> Should I expect this to work, or is some part of my workflow wrong?
>>>>
>>>> I put the full log and just the extracted MIR file online:
>>>> https://drive.google.com/open?id=1Br0s9Qvr4tzPv8nqbnV_nWezpEH5Ci7B and
>>>> would appreciate any guidance whether I should file this as a deserialiser
>>>> bug.
>>>>
>>>> Best,
>>>> Valentin
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> LLVM Developers mailing list
>>>> llvm-dev at lists.llvm.org
>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>>
>>>>
>>>
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> llvm-dev at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>
>>>
>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20180320/54dbd4fb/attachment.html>