llvm dev - Jul 2013 - [LLVMdev] Passing String to an external function in llvm

I did some computation through llvm pass, and store those computed values on
string.  eg. :-

stringstream lhs;
lhs << instr->getOperand(1);   //  'instr' is some instruction
string lhsvar=lhs.str();

Now I want to pass this 'lhsvar' to the external function, so how can i
do
this???

This is just the part of a code to make you understand. if you say I can
even provide the link to the code.







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On Thu, Jul 25, 2013 at 10:12 AM, Abhinash Jain <omnia at mailinator.com>
wrote:
> I did some computation through llvm pass, and store those computed values
on
> string.  eg. :-
>
> stringstream lhs;
> lhs << instr->getOperand(1);   //  'instr' is some
instruction
> string lhsvar=lhs.str();
>
> Now I want to pass this 'lhsvar' to the external function, so how
can i do
> this???
Why are you storing this in a string at all - just use the operand
itself, it will be the LLVM Value you want to pass to the function.
>
> This is just the part of a code to make you understand. if you say I can
> even provide the link to the code.
>
>
>
>
>
>
>
> --
> View this message in context:
http://llvm.1065342.n5.nabble.com/Passing-String-to-an-external-function-in-llvm-tp59798p59803.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

Thanx for the response.

 %x = alloca i32, align 4
 %y = alloca i32, align 4
 %a = alloca i32, align 4
 %t = alloca i32, align 4

1. %10 = load i32* %x, align 4
2. %11 = load i32* %y, align 4
3. %div = sdiv i32 %10, %11
4. %12 = load i32* %a, align 4
5. %mul4 = mul nsw i32 %div, %12

6. store i32 %mul4, i32* %t, align 4
a.		  %mul4 = mul nsw i32 %div, %12
b.		  %div = sdiv i32 %10, %11
c.		  %10 = load i32* %x, align 4
d.		  %11 = load i32* %y, align 4
e.		  %12 = load i32* %a, align 4

This is a IR of       " t = x/y*a " 
The address of the "%x, %y, %a" are "0xbe4ab94, 0xbe4abd4,
0xbe4ac54"
respectively.
and the opcode of "*, /" are "12, 15" respectively.

Point (6.a to 6.e)  are the result of use-def chain, with the help of which
I managed to make a string as -

"12_15_0xbe4ab94_0xbe4abd4_0xbe4ac54" (by converting getOpcode() and
getOperand() to string and than concatenating it)

Now I want to pass this whole string to some other external function, How
can I do this? 

If you want I can show you the full code.



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