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<p>Thanks a million!</p>
<p>I've finally went to the object file containing foo function and using objdump tool I found the exact used name in its symbol table. Using this mangled name in my pass, solved the resolve issue and my foo function is finally called correctly.</p>
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<div class="PlainText">Regards,<br>
Marwa Yusuf<br>
Teaching Assistant - Computer Engineering Department<br>
Faculty of Engineering - Benha University<br>
E-JUST PhD Student<br>
Computer Science & Engineering Dept.</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> mats.o.petersson@googlemail.com <mats.o.petersson@googlemail.com> on behalf of mats petersson <mats@planetcatfish.com><br>
<b>Sent:</b> Wednesday, September 2, 2015 4:36 PM<br>
<b>To:</b> marwayusuf@feng.bu.edu.eg<br>
<b>Cc:</b> llvm-dev<br>
<b>Subject:</b> Re: [llvm-dev] creating a callinst to an external function</font>
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<div>If you look at the computer output of the file that provides the function `myclass::foo` (-S -emit-llvm if you use clang), you should see that the name of the function (probably) isn't `foo`. You need to precisely match the name between the caller and
the actual function. <br>
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Mats<br>
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<div class="gmail_quote">On 2 September 2015 at 15:17, <a href="mailto:marwayusuf@feng.bu.edu.eg">
marwayusuf@feng.bu.edu.eg</a> via llvm-dev <span dir="ltr"><<a href="mailto:llvm-dev@lists.llvm.org" target="_blank">llvm-dev@lists.llvm.org</a>></span> wrote:<br>
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<p>I tried to remove parameters from the called function "foo". So I got a different error.</p>
<p>LLVM ERROR: Program used external function 'foo' which could not be resolved!<br>
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<p>Any help?</p>
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<div>Regards,<br>
Marwa Yusuf<br>
Teaching Assistant - Computer Engineering Department<br>
Faculty of Engineering - Benha University<br>
E-JUST PhD Student<br>
Computer Science & Engineering Dept.</div>
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<div dir="ltr"><font color="#000000" face="Calibri, sans-serif" style="font-size:11pt"><b>From:</b> llvm-dev <<a href="mailto:llvm-dev-bounces@lists.llvm.org" target="_blank">llvm-dev-bounces@lists.llvm.org</a>> on behalf of
<a href="mailto:marwayusuf@feng.bu.edu.eg" target="_blank">marwayusuf@feng.bu.edu.eg</a> via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" target="_blank">llvm-dev@lists.llvm.org</a>><br>
<b>Sent:</b> Thursday, August 20, 2015 12:42 AM<br>
<b>To:</b> <a href="mailto:llvm-dev@lists.llvm.org" target="_blank">llvm-dev@lists.llvm.org</a><br>
<b>Subject:</b> [llvm-dev] creating a callinst to an external function</font>
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<p>Dear All</p>
<p>I'm making an instrumentation pass. The pass is supposed to modify the given IR in a specefic way. One of the required modifications is to insert a call to a function at a specific location. </p>
<p>This is the signature of the called function:</p>
<p> void myclass::foo(Function *f, BasicBlock* b)</p>
<p>This function's prototype is in an foofile.h file in include/llvm</p>
<p>And the function definition is in foofile.cpp file in the MCJIT folder.</p>
<p>and running "make" at this folder works fine and the foofile.cpp is compiled with MCJIT.cpp and another function in the same file works just fine as expected.</p>
<p>Not back to the instrumentation pass. How can I insert a callinst to the foo function in the given IR?</p>
<p>Here is the snippet that inserts the call:</p>
<p> Type* retTy = Type::getInt32Ty(C);</p>
<p> FunctionType* FuncTy = FunctionType::get(retTy, false);</p>
<p> PointerType* PtrToFuncTy = PointerType::get(FuncTy, 0);</p>
<p></p>
<p> Constant *fun = M->getOrInsertFunction("foo", Type::getVoidTy(C), PtrToFuncTy, Type::getLabelTy(C), nullptr);</p>
<p></p>
<p> Function *dofoo = cast<Function>(fun);</p>
<p> Instruction* dofooCall = CallInst::Create(fun, Args2, "", bb);</p>
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</p>
<p>Note: Args2 is an arraylist containing 2 value pointers to a function and a basicblock, bb is the basicblock to insert the call in.</p>
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<p>When I run the pass using op on a given IR, it produces a declaration and a call correctly like this:</p>
<p> declaration: declare void @foo(i32 ()*, label)</p>
<p> call: call void @foo(i32 ()* @main, label %for.cond)</p>
<p>But when I try to run the resulting .ll file using lli, everything explodes! This the first 2 lines before the stacktrace:</p>
<p> Can't get register for value!</p>
<p> UNREACHABLE executed at /home/marwayusuf/llvm-env/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp:1158!</p>
<p> </p>
<p>I concluded that the problem is it can't find the foo function. If this is the problem, how can I create the callinst correctly?</p>
<p> </p>
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<div>Regards,<br>
Marwa Yusuf<br>
Teaching Assistant - Computer Engineering Department<br>
Faculty of Engineering - Benha University<br>
E-JUST PhD Student<br>
Computer Science & Engineering Dept.</div>
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