[llvm-dev] How to split module into several ones

[Aliaksei Zasenka via llvm-dev]

> What is your ld version?
I've used ld 2.23.1 from MinGW package for my tests. This is quite old
version. As far as I remember the gold-plugin is not supported on Windows
for now.

As for linker, I need following features:
-ability to build windows dll
-ability to embed debug info compatible to gdb
-own crt (like MinGW has)


I'm going to try lld with MinGW crt again (my recent attempts failed for
some reason)


2016-11-17 17:29 GMT+03:00 Teresa Johnson <tejohnson at google.com>:

>
>
> On Thu, Nov 17, 2016 at 1:37 AM, Aliaksei Zasenka via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> 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?
>>
>
> What is your ld version? The Gold ld can invoke LLVM's gold-plugin when
> given bitcode input files, which will perform LTO. However, while the GNU
> ld recently gained the ability to invoke LLVM's gold-plugin to do this for
> bitcode, it is not a configuration we test, so I'd recommend Gold ld. Also,
> LLVM's lld has support for bitcode inputs and will also invoke LTO. For the
> gold plugin, see http://llvm.org/docs/GoldPlugin.html for ensuring it is
> configured properly.
>
> Teresa
>
>
>> 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
>>>
>>>
>>
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
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>>
>>
>
>
> --
> Teresa Johnson |  Software Engineer |  tejohnson at google.com |
> 408-460-2413
>
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