[llvm-dev] Linking LLVM IR with standard library

[Shilpa B via llvm-dev]

Hi Mats,

Thanks for pointing out. Your suggestion solved my problem.
You have been of great help.

Cheers..:)

Thanks,
Shilpa

On Fri, Nov 18, 2016 at 11:36 PM, mats petersson <mats at planetcatfish.com>
wrote:

> Do reply to ALL recipients (in particular to the mailing list) when
> replying!
>
>
>
> On 18 November 2016 at 17:27, Shilpa B <shilpabvb at gmail.com> wrote:
>
>> Hi Mats,
>>
>> Thanks for the reply and the link. I am attaching the sample file that I
>> had used to test.
>> It is an LLVM IR file and I modified it to include rand function to
>> generate random numbers and used the command
>>
>> clang print.ll -std=c++11 -Wl,-rpath,/usr/include  -o print.o
>>
>> to generate the executable file. However, when I execute print.o it shows
>> the random numbers generated as zero.
>>
>
> Nope, rand is (most likely) returning correct values you are printing
> floating point values from integer values, and that quite often results in
> zero being printed - depending on the architecture, register vs. memory
> used for varargs, etc.
>
> ....
> @.str = private unnamed_addr constant [4 x i8] c"%f\09\00", align 1
> ....
>   %callr = call i32 @rand()
>   store i32 %callr, i32* %arrayidx5, align 8
>   %val = load i32, i32* %arrayidx5, align 8
>   %call = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x
> i8], [4 x i8]* @.str, i32 0, i32 0), i32 %val)
> ....
>
> change %f to %d, and it lists a bunch of seemingly random numbers, at
> least on my machine.
>
> --
> Mats
>
>>
>> Thanks,
>> Shilpa
>>
>> On Fri, Nov 18, 2016 at 9:39 PM, mats petersson <mats at planetcatfish.com>
>> wrote:
>>
>>> Without reproducible steps, it's hard to give meaningful advice. In my
>>> experience, linking using `clang` (or `gcc`) will work.
>>>
>>> My compiler does that around in this function:
>>> https://github.com/Leporacanthicus/lacsap/blob/master/binary.cpp#L126
>>>
>>> --
>>> Mats
>>>
>>> On 18 November 2016 at 11:20, Shilpa B via llvm-dev <
>>> llvm-dev at lists.llvm.org> wrote:
>>>
>>>> Hi,
>>>>
>>>> I have a LLVM IR file generated for a different source language (Not
>>>> C). I have added a rand() function in it to generate random numbers.
>>>>
>>>> I compiled the .ll file to .o using clang. However, when I execute the
>>>> .o file all generated numbers are zeros.
>>>>
>>>> How should I link the .ll file with the standard library for the clang
>>>> to generate the random numbers?
>>>>
>>>>
>>>> Thanks
>>>> -Shilpa
>>>>
>>>> _______________________________________________
>>>> LLVM Developers mailing list
>>>> llvm-dev at lists.llvm.org
>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>>
>>>>
>>>
>>
>
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