[PATCH] D30080: MC/COFF: Do not emit forward associative section referenceds.

[Rui Ueyama via llvm-commits]

Okay. I'll try that tomorrow.

On Thu, Feb 16, 2017 at 9:52 PM, David Majnemer <david.majnemer at gmail.com>
wrote:

> No, COMDATs cannot be associated in that way. They should always form a
> DAG.
>
>
> On Thu, Feb 16, 2017 at 9:47 PM, Rui Ueyama <ruiu at google.com> wrote:
>
>> That is probably not hard indeed, but you can create cycles if you use
>> LLVM IR, can't you?
>>
>> On Thu, Feb 16, 2017 at 9:33 PM, David Majnemer <david.majnemer at gmail.com
>> > wrote:
>>
>>> I believe its possible via LLVM IR, I don't think it'd be too hard to
>>> make it work.
>>>
>>>
>>> On Thu, Feb 16, 2017 at 6:53 PM, Rui Ueyama <ruiu at google.com> wrote:
>>>
>>>> On Thu, Feb 16, 2017 at 6:49 PM, David Majnemer <
>>>> david.majnemer at gmail.com> wrote:
>>>>
>>>>> Does MSCOFF permit chains of associated sections? I can't remember if
>>>>> they do.
>>>>>
>>>>
>>>> IIRC that is not explicitly banned by the spec, but no one produces
>>>> chained associated sections, and I can't imagine a valid of use it.
>>>>
>>>>
>>>>> On Thu, Feb 16, 2017 at 6:35 PM Rui Ueyama via Phabricator via
>>>>> llvm-commits <llvm-commits at lists.llvm.org> wrote:
>>>>>
>>>>>> ruiu created this revision.
>>>>>>
>>>>>> MSVC link.exe cannot handle associative sections that refer later
>>>>>> sections in the section header. Technically, such COFF object doesn't
>>>>>> violate the Microsoft COFF spec, as the spec doesn't say anything
>>>>>> about that, but still we should avoid doing that to make it compatible
>>>>>> with MS tools.
>>>>>>
>>>>>> This patch assigns smaller section numbers to non-associative sections
>>>>>> and larger numbers to associative sections. This should resolve the
>>>>>> compatibility issue.
>>>>>>
>>>>>>
>>>>>> https://reviews.llvm.org/D30080
>>>>>>
>>>>>> Files:
>>>>>>   llvm/lib/MC/WinCOFFObjectWriter.cpp
>>>>>>   llvm/test/DebugInfo/COFF/globals.ll
>>>>>>   llvm/test/DebugInfo/COFF/types-data-members.ll
>>>>>>   llvm/test/MC/COFF/section-comdat.s
>>>>>>
>>>>>> _______________________________________________
>>>>>> llvm-commits mailing list
>>>>>> llvm-commits at lists.llvm.org
>>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>>>>>>
>>>>>
>>>>
>>>
>>
>
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