llvm dev - Jul 2009 - [LLVMdev] Where does llvm.memcpy.i64 and friends get lowered ?

2009/7/19 Chris Lattner <clattner at apple.com>
>   On Jul 18, 2009, at 3:28 PM, Aaron Gray wrote:
>
> 2009/7/18 Chris Lattner <clattner at apple.com>
>
>>   On Jul 18, 2009, at 2:56 PM, Aaron Gray wrote:
>>
>>  I am iterating through Modules symbols for
'test/CodeGen/X86/memcpy.bc
>>
>>
>> If you're iterating over functions, just ignore all intrinsics.
>>
>
> Okay, but it would be nice if the Module object reflected the lowered
> symbol names like 'memcpy' too. It seems a bit of an inconsistancy
for the
> Module not to reference this and have to pick it up from the relocations.
>
>
> If you're iterating over the Module, you're not dealing with the
codegen
> level.  We want the code generator to change as little as possible when
> doing codegen.
>
No I'm doing the COFFWriter, its just that symbols are being introduced via
relocations, but AFAICT they are not defined in the Module. This seems to be
happening with memcpy and friends.

>
>  Also there is the matter of 'abort' which seems to be defined by
most if
> not all modules even if it is not being used. I am
> using GlobalValue::getUses() to filter it. Whats going on with
'abort' ?
>
>
> I have no idea what you're talking about.
>
There is a function symbol called 'abort' that is being defined, whether
it
is used or not. Its not defined in the '.ll' file and useage count is
zero, yet it is always nearly defined. I think there were a few test cases
where it was not present, I will have to double check this.

Aaron

>
> -Chris
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>
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I am getting a simular problem with ___main appearing if '@main' is used
but
there is no instance of it in the Module iterators, only in the relocations.

Is it possible to do something about these 'ghost symbols' and have them
defined in Module. Rather than having to check for them and pick them up
when processing relocations.

Aaron

2009/7/19 Aaron Gray <aaronngray.lists at googlemail.com>
> 2009/7/19 Chris Lattner <clattner at apple.com>
>
>>   On Jul 18, 2009, at 3:28 PM, Aaron Gray wrote:
>>
>> 2009/7/18 Chris Lattner <clattner at apple.com>
>>
>>>   On Jul 18, 2009, at 2:56 PM, Aaron Gray wrote:
>>>
>>>  I am iterating through Modules symbols for
'test/CodeGen/X86/memcpy.bc
>>>
>>>
>>> If you're iterating over functions, just ignore all intrinsics.
>>>
>>
>> Okay, but it would be nice if the Module object reflected the lowered
>> symbol names like 'memcpy' too. It seems a bit of an
inconsistancy for the
>> Module not to reference this and have to pick it up from the
relocations.
>>
>>
>> If you're iterating over the Module, you're not dealing with
the codegen
>> level.  We want the code generator to change as little as possible when
>> doing codegen.
>>
>
> No I'm doing the COFFWriter, its just that symbols are being introduced
via
> relocations, but AFAICT they are not defined in the Module. This seems to
be
> happening with memcpy and friends.
>
>
>>
>>  Also there is the matter of 'abort' which seems to be defined
by most if
>> not all modules even if it is not being used. I am
>> using GlobalValue::getUses() to filter it. Whats going on with
'abort' ?
>>
>>
>> I have no idea what you're talking about.
>>
>
> There is a function symbol called 'abort' that is being defined,
whether it
> is used or not. Its not defined in the '.ll' file and useage count
is
> zero, yet it is always nearly defined. I think there were a few test cases
> where it was not present, I will have to double check this.
>
> Aaron
>
>
>>
>> -Chris
>>
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>>
>>
>
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> I am getting a simular problem with ___main appearing if '@main' is
used but
> there is no instance of it in the Module iterators, only in the
relocations.
> Is it possible to do something about these 'ghost symbols' and have
them
> defined in Module. Rather than having to check for them and pick them up
> when processing relocations.
Unfortunately, no. Such symbols are emitted during codegeneration only
and are target-specific. There is no tight connection with Module at
this time.

-- 
With best regards, Anton Korobeynikov
Faculty of Mathematics and Mechanics, Saint Petersburg State University

On Jul 19, 2009, at 8:35 AM, Aaron Gray wrote:
> I am getting a simular problem with ___main appearing if '@main' is
> used but there is no instance of it in the Module iterators, only in  
> the relocations.
>
> Is it possible to do something about these 'ghost symbols' and have
> them defined in Module. Rather than having to check for them and  
> pick them up when processing relocations.
You should not be walking the module.

-Chris
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