[LLVMdev] llvm-ar llvm-link

[ankur deshwal]

Please help with the foreseeable shortcoming of the techniques discussed/
better alternate technique. These context for the problem is opencl builtin
libs.

Thanks,
Ankur


On Fri, Feb 22, 2013 at 6:42 AM, ankur deshwal <a.s.deshwal at gmail.com>wrote:

> Hi Ahmad,
>
> Yes, merging works good.
>
> However, my problem is like this - I have a C library which consists of
> 1000's of functions spread through various files. The functions do not have
> dependency amoung each other. I want to link only relavant files( files
> which have functions called from my application). Since ar has a global
> symbol table, I believe it should be faster to look for a symol in the
> table and pull out and link the file to .bc of my application.
>
> Is my understand regarding llvm-ar correct? Or is there a better way to
> achieve it?
>
> One not-so-great solution I can think of is compile the library into
> separate .bc files and write llvm pass which has a predefined hash mapping
> of the names of functions these bc files. So while compiling, I look for
> only relavant files and link them using code form llvm-link.
>
> OR. rather than linking the files, only extract the function from the
> library .bc file and insert it into module of application .bc.
>
> Does any of the idea make sense ? Which one will be doable+preferable?
>
>
> Thanks a lot,
> Ankur
>
>
>
>
>
>
> On Thu, Feb 21, 2013 at 11:51 PM, Hassan, Ahmad <ahmad.hassan at sap.com>wrote:
>
>>  Hi Ankur,****
>>
>> ** **
>>
>> ** **
>>
>> Why do you need archive in this case? The other way of doing this is to
>> merge all bitcode files into single file:****
>>
>> ** **
>>
>>  $ clang -c -emit-llvm abc.c –o abc.bc****
>>
>>  $  clang -c -emit-llvm bcd.c –o bcd.bc****
>>
>> llvm-link bcd.bc abc.bc –o merged.bc****
>>
>> ** **
>>
>> Cheers,****
>>
>> Ahmad****
>>
>> ** **
>>
>> *From:* llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu]
>> *On Behalf Of *ankur deshwal
>> *Sent:* 21 February 2013 17:54
>> *To:* llvmdev at cs.uiuc.edu; ankur deshwal
>> *Subject:* [LLVMdev] llvm-ar llvm-link****
>>
>> ** **
>>
>> Hi,****
>>
>> ** **
>>
>> I tried to build an llvm archive and link it against an llvm bc file.
>> However, it fails. Following is the procedure I followed ( abc.c is file
>> which calls a function whose definition is present in bcd.c)****
>>
>> ** **
>>
>>  $ clang -c -emit-llvm abc.c ****
>>
>>  $  clang -c -emit-llvm bcd.c ****
>>
>>  $  llvm-ar cr bsd.ar bcd.o ****
>>
>>  $  llvm-link abc.o bsd.ar****
>>
>> ** **
>>
>> llvm-link: bsd.ar:1:2: error: expected integer****
>>
>> !<arch>****
>>
>>  ^****
>>
>> llvm-link: error loading file 'bsd.ar'****
>>
>> ** **
>>
>> What am I missing here ? ****
>>
>> ** **
>>
>> Regards,****
>>
>> Ankur****
>>
>
>
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