[llvm-dev] [GPUCC] how to remove _ZL21__nvvm_reflect_anchorv() automatically?

[Jingyue Wu via llvm-dev]

Artem,

With David's http://reviews.llvm.org/rL265060, do you think
__nvvm_reflect_anchor is still necessary?

On Fri, Apr 8, 2016 at 9:37 AM, Yuanfeng Peng via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

> Yeah, '.' is the direct reason for the ptxas failure here.  I'm curious,
> however, about what the purpose of nvvm_reflect_anchorv() is here, and why
> does the front-end always generate this function? Since the current PTX
> emission doesn't mangle dots, it would be a reasonable workaround for me to
> prevent the front-end from generating this function in the first place.
> Is there any magic option available to do so?
>
> Thanks!
> yuanfeng
>
> On Thu, Apr 7, 2016 at 5:19 PM, Reid Kleckner <rnk at google.com> wrote:
>
>> The actual problem here is that PTX appears to not allow '.' in symbol
>> names. We should probably just change our PTX emission to mangle dots
>> somehow.
>>
>> On Thu, Apr 7, 2016 at 4:24 PM, Yuanfeng Peng via llvm-dev <
>> llvm-dev at lists.llvm.org> wrote:
>>
>>> Hi,
>>>
>>> I needed to compile a cuda source file (say, a.cu) into IR (a.bc), and
>>> then merge a.bc with another bitcode file (b.bc, compiled from b.cu).
>>> So I used *llvm-link a.bc b.bc -o c.bc*
>>>
>>> However, I noticed that an internal function '* _ZL21__nvvm_reflect_anchorv()
>>> *' is defined in both a.bc & b.bc, and when merging these two files,
>>> one of the two definitions was renamed to  '
>>> *_ZL21__nvvm_reflect_anchorv.2()*', and written into c.bc.
>>>
>>>  Then I did *llc c.bc -o c.s -march=nvptx ; ptxas c.s -o c.o*
>>>
>>> However, ptxas would give the following complaint:
>>>
>>> *ptxas c.s, line 171; error   : Duplicate definition of function
>>> '_ZL21__nvvm_reflect_anchorv'*
>>>
>>> *ptxas c.s, line 171; fatal   : Parsing error near '.2': syntax error*
>>>
>>> So I inspected c.s and found the issue above was caused by the following
>>> line:
>>>
>>> .*func**  (.param .b32 func_retval0) _ZL21__nvvm_reflect_anchorv.2() //
>>> @_ZL21__nvvm_reflect_anchorv.2*
>>>
>>> After I manually deleted the definition of this function in c.s, the
>>> compilation works file.  I wonder how could I force llc to remove  *`*
>>> _ZL21__nvvm_reflect_anchorv.2*()`*? Or is that possible to prevent
>>> _ZL21__nvvm_reflect_anchorv*() *from being generated into a.bc & b.bc
>>> in the first place?  Or is this possible to ask llvm-link to NOT rename
>>> *_ZL21__nvvm_reflect_anchorv() **into **ZL21__nvvm_reflect_anchorv**.2*
>>> *()*?
>>>
>>>
>>> Thanks!
>>>
>>> *Yuanfeng Peng *
>>>
>>>
>>>
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> llvm-dev at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>
>>>
>>
>
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