[LLVMdev] Can I add GlobalVariable in MachineFunctionPass ?

[Justin Holewinski]

Can you tell us a bit more about what you're trying to accomplish?

Changes to the IR performed during MachineFunctionPass::doInitialization
will likely propagate down through code generation, but at that point what
is the purpose of using a MachineFunctionPass?  You won't have any analysis
or instruction information available until runOnMachineFunction.


On Mon, Aug 5, 2013 at 12:00 PM, Anthony Yu <swpenim at gmail.com> wrote:

> Micah,
>
> Thanks for your help. I will study on that code.
>
>
> Justin,
>
> Sorry for my misleading word. Local memory in OpenCL is the same as share
> memory in CUDA. What I mean is share memory, so MachineFrameInfo is not
> suitable to me.
> And I need codegen data, so FunctionPass is also not suitable.
> Anyway, thanks for the suggestion.
>
> Antony
>
>
>
> 2013/8/5 Justin Holewinski <justin.holewinski at gmail.com>
>
>> If you're running a MachineFunctionPass, then the code has already been
>> lowered to machine instructions and modifying the original IR will most
>> likely not do what you want.  You should only be using the IR as an
>> immutable object for reference.  If you want to change the IR, I would
>> suggest using a FunctionPass instead of a MachineFunctionPass.  Unless you
>> need codegen data.
>>
>> At the MachineInstr level, to allocate local memory you can use the
>> MachineFrameInfo interface.  This provides methods like CreateStackObject
>> to allocate a new stack slot (which will be lowered to local memory in
>> PTX).  The return value of these methods is an integer that represents a
>> FrameIndex.  You can treat this as a pointer to your allocated object.  You
>> will also need to emit the proper MachineInstr-level loads and stores to
>> access the object.
>>
>>
>> On Mon, Aug 5, 2013 at 11:00 AM, Anthony Yu <swpenim at gmail.com> wrote:
>>
>>> Micah,
>>>
>>> As you expected, I am trying to create local memory but in the NVPTX
>>> backend. It's really not convenient that I can't create local memory in
>>> runOnMachineFunction.
>>> Hmm....
>>> Since I should do it at doInitialization stage, I also need to do some
>>> tricks in global variable and AsmPrinter to resize it.
>>> Did you use the similar way?
>>>
>>> Antony
>>>
>>>
>>>
>>>
>>> 2013/8/5 Micah Villmow <micah.villmow at smachines.com>
>>>
>>>> Antony,
>>>>  What are you trying to accomplish in this case? I did something very
>>>> similar in the AMDIL backend, but it was not the cleanest solution and you
>>>> are correct it has to be do at doInitialization stage and not at
>>>> runOnMachineFunction.
>>>> Micah
>>>>
>>>> > -----Original Message-----
>>>> > From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu
>>>> ]
>>>> > On Behalf Of Antony Yu
>>>> > Sent: Monday, August 05, 2013 3:41 AM
>>>> > To: llvmdev at cs.uiuc.edu
>>>> > Subject: [LLVMdev] Can I add GlobalVariable in MachineFunctionPass ?
>>>> >
>>>> > Hello,
>>>> >
>>>> > I want to add a global variable of arrayType in my
>>>> MachineFunctionPass.
>>>> > However, I only get const Module from
>>>> > MachineFunction.getMMI().getModule().
>>>> > I can't add any global variable to a const Module.
>>>> > Another way is to add a global variable in doInitialization in my
>>>> > MachineFunctionPass, but I can't determine the size of my arrayType
>>>> for
>>>> > global variable in doInitialization.
>>>> >
>>>> > Is there any suggestion that can help me achieve this?
>>>> >
>>>> > Thanks in advance.
>>>> > Antony Yu
>>>> >
>>>> >
>>>> >
>>>> > --
>>>> > View this message in context:
>>>> http://llvm.1065342.n5.nabble.com/Can-I-add-
>>>> > GlobalVariable-in-MachineFunctionPass-tp60165.html
>>>> > Sent from the LLVM - Dev mailing list archive at Nabble.com.
>>>> > _______________________________________________
>>>> > 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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>>>
>>
>>
>> --
>>
>> Thanks,
>>
>> Justin Holewinski
>>
>
>


-- 

Thanks,

Justin Holewinski
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