如何使用llvm pass插入内联汇编指令

#include "llvm/Pass.h"
#include "llvm/IR/Function.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/InlineAsm.h"

using namespace llvm;

namespace {
  struct InlineAsmInsertionPass : public FunctionPass {
    static char ID;
    InlineAsmInsertionPass() : FunctionPass(ID) {}

    bool runOnFunction(Function &F) override {
      // 获取函数的第一个指令
      BasicBlock &BB = *F.begin();
      Instruction *FirstInst = BB.getFirstInsertionPt();

      // 创建内联汇编指令
      InlineAsm *IA = InlineAsm::get(F.getType(), "nop", "", false, false, 0, AsmDialect::Att);

      // 插入内联汇编指令到函数的开始处
      BB.getInstList().insert(FirstInst, IA);

      return true;
    }
  };
}

char InlineAsmInsertionPass::ID = 0;
static RegisterPass<InlineAsmInsertionPass> X("inline-asm-insert", "Insert Inline Assembly Instruction Pass", false, false);