llvm dev - Apr 2018 - How to create a proper MachineMemOperand?

Hi all,
I met a new problem in the process of my project.
I have got an address by mmap. And I want to build a MachineInstr of
MOV64mr to move a value to the address. But it seems that the
MachinePointerInfo needs a pointer to a Value.
So can I create a MachineMemOperand directly with the address (is a long*)
? Or I need to try some other methods?
Thanks a lot,
Will
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Usually I will search the target directory, X86 in your case, to see
how MOV64mr is used with BuildMI to generate the instruction I want.

2018-04-16 16:25 GMT+08:00 Will Lester via llvm-dev <llvm-dev at
lists.llvm.org>:
> Hi all,
> I met a new problem in the process of my project.
> I have got an address by mmap. And I want to build a MachineInstr of
MOV64mr
> to move a value to the address. But it seems that the MachinePointerInfo
> needs a pointer to a Value.
> So can I create a MachineMemOperand directly with the address (is a long*)
?
> Or I need to try some other methods?
> Thanks a lot,
> Will
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>


-- 
Wei-Ren Chen (陳韋任)
Homepage: https://people.cs.nctu.edu.tw/~chenwj

Thanks for your advice. But I have searched X86 and find no more
information than I have known.
The problem is not to create a MachineMemOperand, but to create a
MachineMemOperand with certain address. This scene does not exist in the
original code.
Since I have to do this in the process of register allocating, inserting IR
instruction seems to be infeasible. I have thought of storing the address
in a global variable in the IR, and loading it afterwards. But it seems to
be improper as mentioned before.
May I do not create a MachineMemOperand, just store the address in a
register, and use some MachineInstr to store the value to the address?

2018-04-16 21:19 GMT+08:00 陳韋任 <chenwj.cs97g at g2.nctu.edu.tw>:
> Usually I will search the target directory, X86 in your case, to see
> how MOV64mr is used with BuildMI to generate the instruction I want.
>
> 2018-04-16 16:25 GMT+08:00 Will Lester via llvm-dev <
> llvm-dev at lists.llvm.org>:
> > Hi all,
> > I met a new problem in the process of my project.
> > I have got an address by mmap. And I want to build a MachineInstr of
> MOV64mr
> > to move a value to the address. But it seems that the
MachinePointerInfo
> > needs a pointer to a Value.
> > So can I create a MachineMemOperand directly with the address (is a
> long*) ?
> > Or I need to try some other methods?
> > Thanks a lot,
> > Will
> >
> > _______________________________________________
> > LLVM Developers mailing list
> > llvm-dev at lists.llvm.org
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> >
>
>
>
> --
> Wei-Ren Chen (陳韋任)
> Homepage: https://people.cs.nctu.edu.tw/~chenwj
>
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