[LLVMdev] llvm line number of an instruction

[Alexandru Ionut Diaconescu]

Hello everybody,


I want to get the line number of an instruction (and also of a variable declaration - alloca and global). The instruction is saved in an array of instructions. I have the function:

    Constant* metadata::getLineNumber(Instruction* I){
        if (MDNode *N = I->getMetadata("dbg")) { // this if is never executed
            DILocation Loc(N);
            unsigned Line = Loc.getLineNumber();
            return ConstantInt::get(Type::getInt32Ty(I->getContext()), Line);
        }   // else {
          //  return NULL; }
    }

and in my main() I have :

    errs()<<"\nLine number is "<<*metadata::getLineNumber(allocas[p]);

the result is NULL since `I->getMetadata("dbg")` is false.

Is there a possibility to enable dbg flags in LLVM without rebuilding the LLVM framework, like using a flag when compiling the target program or when running my pass (I used -debug) ? 

Compiling a program with “-O3 -g” should give full debug information, but I still have the same result. I am aware of http://llvm.org/docs/SourceLevelDebugging.html , from where I can see that is quite easy to take the source line number from a metadata field.

PS: for Allocas, it seems that I have to use findDbgDeclare method from DbgInfoPrinter.cpp.

Thank you in advance !
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