[LLVMdev] runtime pass

[marwayusuf@feng.bu.edu.eg]

First, thanks for your help.

Actually, I mean the second one, runtime of application. I've already made some instrumentation in the given IR, but only to add some extra code and change some variables. Now, if I want to instrument it to call some function that is able to parse stackmap section in the object file and change the given IR itself, is that possible?


Regards,
Marwa Yusuf
Teaching Assistant - Computer Engineering Department
Faculty of Engineering - Benha University
E-JUST PhD Student
Computer Science & Engineering Dept.


________________________________
From: Stephen Thomas <stephen.warner.thomas at gmail.com>
Sent: Wednesday, July 15, 2015 9:20 PM
To: marwayusuf at feng.bu.edu.eg
Cc: llvmdev at cs.uiuc.edu
Subject: Re: [LLVMdev] runtime pass

Marwa,

By "runtime", are you referring to the runtime of opt? If so, I assume your question is about how to make sure certain passes run before your pass runs, so that their results are available to your pass. The "Writing an LLVM Pass" doc has a nice section on the interaction between passes:

http://llvm.org/docs/WritingAnLLVMPass.html#specifying-interactions-between-passes

Alternatively, if by "runtime", you are referring to the runtime of the application under analysis, then that's trickier. LLVM is designed to run analysis and transformation passes at compilation time, not runtime. So it depends on what you're trying to do. If you're trying to profile the application to, e.g., gather values of certain variables, that's certainly possible by first writing a transformation pass that instruments the IR with calls at certain points in the target application.

Cheers,
Steve



On Wed, Jul 15, 2015 at 10:05 AM, marwayusuf at feng.bu.edu.eg<mailto:marwayusuf at feng.bu.edu.eg> <marwayusuf at feng.bu.edu.eg<mailto:marwayusuf at feng.bu.edu.eg>> wrote:

Dear All

I need to create a pass that is triggered to run at a specific point during runtime. Also, this pass needs to have access to object file and to be able to modify the original IR. Any idea how to make such pass?


Regards,
Marwa Yusuf
Teaching Assistant - Computer Engineering Department
Faculty of Engineering - Benha University
E-JUST PhD Student
Computer Science & Engineering Dept.

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