llvm dev - Aug 2011 - [LLVMdev] running a module pass via opt on multiple bitcode files

Hi,

I'm trying to implement a module pass as a share object to process an entire
program as a unit. The target program is built from multiple object files, hence
multiple bitcode files. However, it seems that opt does not take the whole
program, but just one bitcode file, "test.bc" in the example run shown
below.

$ opt -load mypass.dylib -mymodulepass < test.bc > /dev/null

How do I run my module pass in a library on a whole program?

Thanks.



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On 7/12/11 4:11 PM, Jinwook Shin (HOTWING) wrote:
>
> Hi,
>
> I'm trying to implement a module pass as a share object to process an 
> entire program as a unit. The target program is built from multiple 
> object files, hence multiple bitcode files. However, it seems that opt 
> does not take the whole program, but just one bitcode file,
"test.bc"
> in the example run shown below.
>
> $ opt -load mypass.dylib -mymodulepass < test.bc > /dev/null
>
> How do I run my module pass in a library on a whole program?
>
Link the bitcode files together into a single bitcode file with 
llvm-ld.  You can then run the single bitcode file through opt.

-- John T.
> Thanks.
>
>
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
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> Link the bitcode files together into a single bitcode file with llvm-ld.
You can
> then run the single bitcode file through opt.
I think it would be better to link them with the (simpler) llvm-link.

Ciao, Duncan.

Thanks John. Your approach worked fine for my small toy program. Now, I would
like to run my module pass on a huge project (still a single executable)
consisting of a few thousand bit code files scattered in many different
directories. And some of them are static libraries. Do you still think it's
a good idea to manually gather and link them with llvm-ld? I've seen other
module pass implementations where they directly patch a specific version of LLVM
or clang, instead of running a shared object implementation with opt. Which
would be the ideal approach to analyze a program with a module pass? Thanks.

From: John Criswell <criswell at illinois.edu<mailto:criswell at
illinois.edu>>
Organization: University of Illinois
Date: Tue, 12 Jul 2011 16:19:06 -0500
To: Jinwook Shin <Jinwook.Shin at microsoft.com<mailto:Jinwook.Shin at
microsoft.com>>
Cc: "llvmdev at cs.uiuc.edu<mailto:llvmdev at cs.uiuc.edu>"
<llvmdev at cs.uiuc.edu<mailto:llvmdev at cs.uiuc.edu>>
Subject: Re: [LLVMdev] running a module pass via opt on multiple bitcode files

On 7/12/11 4:11 PM, Jinwook Shin (HOTWING) wrote:
Hi,

I'm trying to implement a module pass as a share object to process an entire
program as a unit. The target program is built from multiple object files, hence
multiple bitcode files. However, it seems that opt does not take the whole
program, but just one bitcode file, "test.bc" in the example run shown
below.

$ opt -load mypass.dylib -mymodulepass < test.bc > /dev/null

How do I run my module pass in a library on a whole program?

Link the bitcode files together into a single bitcode file with llvm-ld.  You
can then run the single bitcode file through opt.

-- John T.



Thanks.







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