C++线程安全分析

C++线程安全分析

除了通过code review或者test来检测线程安全,有没有其它更好的办法?

答案是存在的,通过clang即可以进行这种检测,编译器对存在的线程安全问题会给出警告。

这种分析方法由Google开发,已经被Google大规模应用,参考
https://static.googleusercontent.com/media/research.google.com/zh-CN//pubs/archive/42958.pdf

示例example.cpp:

#include "mutex.h"

class BankAccount {
private:
  Mutex mu;
  int   balance GUARDED_BY(mu);

  void depositImpl(int amount) {
    balance += amount;       // WARNING! Cannot write balance without locking mu.
  }

  void withdrawImpl(int amount) REQUIRES(mu) {
    balance -= amount;       // OK. Caller must have locked mu.
  }

public:
  void withdraw(int amount) {
    mu.Lock();
    withdrawImpl(amount);    // OK.  We've locked mu.
  }                          // WARNING!  Failed to unlock mu.

  void transferFrom(BankAccount& b, int amount) {
    mu.Lock();
    b.withdrawImpl(amount);  // WARNING!  Calling withdrawImpl() requires locking b.mu.
    depositImpl(amount);     // OK.  depositImpl() has no requirements.
    mu.Unlock();
  }
};

通过然后指定-Wthread-safety编译选项,即clang -c -Wthread-safety example.cpp命令编译即可以给出警告。

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.