[LLVMdev] Inserting a function call into bitcode

[Nick Lewycky]

Have you tried running the verifier after ConditionProfile runs? Just 
add it to the pass manager to run right afterwards and see what it picks up.

Nick

Nehal Gandhi wrote:
>
>
> Hi All,
>
> I am trying to write code for simple instrumentation. What I want to do
> is to insert a call to an external function for result of each
> conditional branch instruction. This external function simply print true
> or false based on the result of condition. The modified code is then
> written into new file. However when I try to link that file with another
> bitcode file (containing external function), it results “/llvm-link:
> error loading file 'newfile.bc'/” error. This error is inconsistent. It
> appears for some programs and not for some other. If it links with other
> file, during execution it produces following error - /Assertion `Addr &&
> "Code generation didn't add function to GlobalAddress table!"' failed/
>
> Below is the code of my pass. It inherits ModulePass and does not have
> any other method except runOnModule. Am I missing something during call
> insertion or bitcode modification? I am using LLVM-2.6. */The same code
> in LLVM-2.5 works correctly/*. (except Type::getInt32Ty, llvm-2.5 has
> Type::Int32Ty and no LLVMContext object)
>
> Thanks,
>
> Nehal
>
> bool ConditionProfile::runOnModule(Module &M)
>
> {
>
> // Iterates through all functions of the module
>
> for(Module::iterator mi = M.begin(), me = M.end(); mi!=me; mi++)
>
> {
>
> // Iterates through all basic blocks of the function
>
> for(Function::iterator fi = mi->begin(), fe = mi->end(); fi!=fe; fi++)
>
> {
>
> BasicBlock::iterator bi = fi->end();
>
> bi--; // Getting the terminator/last instruction of BasicBlock
>
> if(isa<BranchInst>(bi))
>
> {
>
> BranchInst *brInst = cast<BranchInst>(bi);
>
> // We are interested in conditional branch only
>
> if(brInst->isUnconditional()) continue;
>
> Value *condRes = brInst->getCondition();
>
> errs()<<"Type:"<<condRes->getType()->getDescription()<<"\n";
>
> // Looking for a function in Module Symbol table
>
> Constant *PrintFn = M.getOrInsertFunction("_Z12PrintCondResb",
> Type::getInt32Ty(context), condRes->getType(), (Type *)0);
>
> if(!PrintFn) {
>
> errs()<<"GetOrInsertFailed\n";
>
> continue;
>
> }
>
> std::vector<Value *> args(1);
>
> args[0] = condRes;
>
> // Creating a call instruction to above function.
>
> CallInst *callInst =
>
> CallInst::Create(PrintFn, args.begin(), args.end(), "", bi);
>
> callInst->setCallingConv(CallingConv::Fast);
>
> }
>
> }
>
> }
>
> // Writing modified module to new file.
>
> std::ostream *os = new std::ofstream("newfile.bc");
>
> WriteBitcodeToFile(&M, *os);
>
> return true;
>
> }
>
>
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev