bool fixupUsedGlobals()

in lib/BPFCov.cpp [97:148]
47 lines of code
18 McCabe index (conditional complexity)

    bool fixupUsedGlobals(Module &M)
    {
        auto U = M.getNamedGlobal("llvm.used");
        if (!U || !U->hasInitializer())
        {
            return false;
        }

        SmallVector<Constant *, 8> UsedGlobals;
        auto UArray = dyn_cast<ConstantArray>(U->getInitializer());
        auto NElems = UArray->getNumOperands();
        for (unsigned int i = 0; i < NElems; i++)
        {
            if (ConstantExpr *CE = dyn_cast<ConstantExpr>(UArray->getOperand(i)))
            {
                auto OC = CE->getOpcode();
                if (OC == Instruction::BitCast || OC == Instruction::GetElementPtr)
                {
                    if (GlobalValue *GV = dyn_cast<GlobalValue>(CE->getOperand(0)))
                    {
                        auto Name = GV->getName();
                        if (!Name.startswith("__llvm_profile_runtime") && !Name.startswith("__profd") && !Name.startswith("__covrec") && !Name.startswith("__llvm_coverage"))
                        {
                            UsedGlobals.push_back(UArray->getOperand(i));
                        }
                    }
                }
            }
            // TODO(leodido) > almost certainly the following doesn't make sense for "llvm.used" array
            else if (GlobalValue *GV = dyn_cast<GlobalValue>(UArray->getOperand(i)))
            {
                auto Name = GV->getName();
                if (!Name.startswith("__llvm_profile_runtime") && !Name.startswith("__profd") && !Name.startswith("__covrec") && !Name.startswith("__llvm_coverage"))
                {
                    UsedGlobals.push_back(UArray->getOperand(i));
                }
            }
        }

        if (UsedGlobals.size() < NElems)
        {
            errs() << "fixing llvm.used\n";
            U->eraseFromParent();
            ArrayType *AType = ArrayType::get(Type::getInt8PtrTy(M.getContext()), UsedGlobals.size());
            U = new GlobalVariable(M, AType, false, GlobalValue::AppendingLinkage, ConstantArray::get(AType, UsedGlobals), "llvm.used");
            U->setSection("llvm.metadata");

            return true;
        }

        return false;
    }