LLVM`opt`给出了传递错误：“Value :: ~Value（）：断言`use_empty（）＆amp;＆amp;”当一个值被销毁时使用保留！“

Question

当我使用opt运行下面的LLVM传递时，收到以下错误消息：

While deleting: i32 %
Use still stuck around after Def is destroyed:  %indexLoc = alloca i32
opt: /home/nlykkei/llvm/src/lib/IR/Value.cpp:85: virtual llvm::Value::~Value(): Assertion `use_empty() && "Uses remain when a value is destroyed!"' failed.

我将opt调用为：opt -load build/flatten/libFlattenPass.so -opCounter loop.rll。

我按照示例将指令插入到http://llvm.org/docs/ProgrammersManual.html#creating-and-inserting-new-instructions中的BB中。

我真的没有看到我的代码有什么问题？我应该明确删除AllocaInst指针还是？

程序：

#include "llvm/Pass.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Instructions.h"
#include "llvm/Support/raw_ostream.h"
#include <map>
#include <string>

using namespace llvm;

namespace {
struct CountOp : public FunctionPass {
    std::map<std::string, int> opCounter;
    std::map<std::string, int> bbNameToId;

    static char ID;
    LLVMContext ctx;

    CountOp() : FunctionPass(ID) {}

    virtual bool runOnFunction(Function &F) {

        std::string bbName("bb");
        int bbId = 0;

        errs() << "Function " << F.getName() << '\n';
        for (Function::iterator bb = F.begin(), e = F.end(); bb != e; ++bb) {

            // assign integer ids to BasicBlock's
            if (bb->hasName()) {
                bbNameToId[bb->getName()] = bbId++;
            } else {
                bb->setName(Twine(bbName + std::to_string(bbId)));
                bbNameToId[bb->getName()] = bbId++;
            }

            for (BasicBlock::iterator i = bb->begin(), e = bb->end(); i != e; ++i) {
                if(opCounter.find(i->getOpcodeName()) == opCounter.end()) {
                    opCounter[i->getOpcodeName()] = 1;
                } else {
                    opCounter[i->getOpcodeName()] += 1;
                }
            }
        }

        AllocaInst* pa = new AllocaInst(Type::getInt32Ty(ctx), 0, "indexLoc");
        BasicBlock& firstBB = F.getBasicBlockList().front();
        Instruction& firstInst = firstBB.front();

        pa->insertBefore(&firstInst);

        std::map <std::string, int>::iterator i = opCounter.begin();
        std::map <std::string, int>::iterator e = opCounter.end();

        while (i != e) {
            errs() << i->first << ": " << i->second << "\n";
            i++;
        }

        i = bbNameToId.begin();
        e = bbNameToId.end();

        while (i != e) {
            errs() << i->first << ": " << i->second << "\n";
            i++;
        }

        errs() << "\n";
        opCounter.clear();
        return false;
    }
};
}

char CountOp::ID = 0;
static RegisterPass<CountOp> X("opCounter", "Counts opcodes per functions");