llvm无法迭代[3 x i8]

Question

I am trying to "parse" a part of LLVM IR. More exactly, from

@.str = private unnamed_addr constant [3 x i8] c"DS\00", section "llvm.metadata"

I want to get "DS". It is the single place in the whole bytecode from where I can get it. I have :

...
Value *VV = cast<Value>(LD100->getOperand(1)->getOperand(0));
errs()<<"\n VV  "<<*(VV)<<"\n";
RESULT : VV  @.str = private unnamed_addr constant [3 x i8] c"DS\00", section "llvm.metadata"

if(VV->getValueID() == Value::GlobalVariableVal){
    GlobalVariable* FD = cast<GlobalVariable>(VV);
    Value *VVV = cast<Value>(FD->getOperand(0));
    errs()<<"\n VVV  "<<*(VVV)<<"\n";
    RESULT :  VVV  [3 x i8] c"DS\00"

    if(VVV->getValueID() == Value::ConstantDataArrayVal){
        ConstantArray *caa = (ConstantArray *)VVV;
        errs()<<"\n "<<(caa->getNumOperands())<<"\n";
        errs()<<"\n "<<*(caa->getType())<<"\n";
        RESULT :  0
                  [3 x i8]
    }

From this point, I tried to cast to every enum llvm::Value::ValueTy in order to try to iterate through [3 X i8], in order to get "DS" (as a StringRef or std::string would be nice), but I cannot. How I can parse this structure?

Thank you for any help !

Answer 1

通过将caa转换为ConstantDataArray然后使用getAsString()来解决它，该方法恰好为我提供了“ DS”。