llvm dev - Oct 2016 - How to split module into several ones

Hi all,
Can anyone give me advice about an appropriate way for extracting number of
functions from module recursively (starting from entry point). Actually it
may be more than one entry point so all dependent functions and global
values must be extracted.

I've tried llvm-extract tool but it can't do work recursively. Maybe it
would be good to write some Call Graph pass or something. Any thoughts?


Thanks in advance,
Alexey Zasenko
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On 10/27/16 11:18 AM, Aliaksei Zasenka via llvm-dev
wrote:
> Hi all,
> Can anyone give me advice about an appropriate way for extracting 
> number of functions from module recursively (starting from entry 
> point). Actually it may be more than one entry point so all dependent 
> functions and global values must be extracted.
>
> I've tried llvm-extract tool but it can't do work recursively.
Maybe
> it would be good to write some Call Graph pass or something. Any thoughts?
I thought llvm-extract conservatively extracted anything that was 
relevant to what it was asked to extract.

In any event, if you need a call graph analysis, there are two call 
graph passes available for LLVM.

The first is the CallGraph pass that comes in the LLVM source tree. It 
is very conservative with function pointers, but its results are 
conservatively correct.

The second is the CallGraph analysis within DSA.  You should be able to 
find a copy for LLVM 3.7 or LLVM 3.8 here 
(https://github.com/jtcriswell/safecode-llvm37) and here 
(https://github.com/jtcriswell/llvm-dsa).

Regards,

John Criswell
>
>
> Thanks in advance,
> Alexey Zasenko
>
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev

-- 
John Criswell
Assistant Professor
Department of Computer Science, University of Rochester
http://www.cs.rochester.edu/u/criswell

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Hi John,
Thanks for your answer.

The CallGraph pass did the work for me. But since I actually have several
modules and my toolchain looked like

llvm-link
<CallGraph extraction pass>
opt
llc

 I've found that llvm-lto is great for doing all the work: greedy linkage,
optimization and further MC generation.
Here the command line I'm using for that:
llvm-lto -exported-symbol=main -save-merged-module -filetype=asm <or obj>
-o %t2 %t1
(I've attached corresponding llvm-lit test.)

Now I'm wondering if there is any possibility to use LTO within the linker
like ld (mingw) to build a dynamic library from my IR code?

Best regards,
Alexey Zasenko


2016-10-28 16:33 GMT+03:00 John Criswell <jtcriswel at gmail.com>:
> On 10/27/16 11:18 AM, Aliaksei Zasenka via llvm-dev wrote:
>
> Hi all,
> Can anyone give me advice about an appropriate way for extracting number
> of functions from module recursively (starting from entry point). Actually
> it may be more than one entry point so all dependent functions and global
> values must be extracted.
>
> I've tried llvm-extract tool but it can't do work recursively.
Maybe it
> would be good to write some Call Graph pass or something. Any thoughts?
>
>
> I thought llvm-extract conservatively extracted anything that was relevant
> to what it was asked to extract.
>
> In any event, if you need a call graph analysis, there are two call graph
> passes available for LLVM.
>
> The first is the CallGraph pass that comes in the LLVM source tree.  It is
> very conservative with function pointers, but its results are
> conservatively correct.
>
> The second is the CallGraph analysis within DSA.  You should be able to
> find a copy for LLVM 3.7 or LLVM 3.8 here (https://github.com/
> jtcriswell/safecode-llvm37) and here (https://github.com/
> jtcriswell/llvm-dsa).
>
> Regards,
>
> John Criswell
>
>
>
> Thanks in advance,
> Alexey Zasenko
>
>
> _______________________________________________
> LLVM Developers mailing listllvm-dev at
lists.llvm.orghttp://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
>
>
> --
> John Criswell
> Assistant Professor
> Department of Computer Science, University of
Rochesterhttp://www.cs.rochester.edu/u/criswell
>
>
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