3

完全编译而不优化

void Add(T data)
{
    node<T> *pNode = new node<T>;
    pNode->m_pNext = NULL;
    pNode->m_data = data;

    uint32_t cPushes;
    uint32_t cPops;
    node<T> *pTail;

    while (true)
    {
        cPushes = m_cPushes;
        cPops = m_cPops;
        pTail = (node<T>*)m_pTail;
        if (cPushes != m_cPushes)
            continue;

        if (!pTail)
            if (CAS2(&m_pTail, NULL, cPushes, (uint32_t)pNode, cPushes +1))
                break;
        else if (CAS(&pTail->m_pNext, NULL, (uint32_t)pNode))
                break;
        else
            CAS2(&m_pTail, (uint32_t)pTail, cPushes, (uint32_t)pTail->m_pNext, cPushes + 1);
    }

    CAS2(&m_pHead, NULL, cPops, (uint32_t)pNode, cPops + 1);
    CAS2(&m_pTail, (uint32_t)pTail, cPushes, (uint32_t)pNode, cPushes + 1);
}

反汇编：http://pastebin.com/7EaH3whu（pastebinned 因为它很大，而且它以某种方式破坏了 SO 的代码标签）

如果你看一下，几乎每条跳转指令的地址都混淆了

例如，如果这个语句失败：'if (!pTail)'，而不是在 'else if' 处继续，它会跳回到循环的开头（实际上，它会跳转到跳转到环形）

完整代码： http: //pastebin.com/U5qGgT0E

4

1 回答 1

8 
    if (!pTail)
        if (CAS2(&m_pTail, NULL, cPushes, (uint32_t)pNode, cPushes +1))
            break;
    else if (CAS(&pTail->m_pNext, NULL, (uint32_t)pNode))
            break;
    else
        CAS2(&m_pTail, (uint32_t)pTail, cPushes, (uint32_t)pTail->m_pNext, cPushes + 1);

是真的

    if (!pTail) {
        if (CAS2(&m_pTail, NULL, cPushes, (uint32_t)pNode, cPushes +1)) {
            break;
        } else if (CAS(&pTail->m_pNext, NULL, (uint32_t)pNode)) {
            break;
        } else {
            CAS2(&m_pTail, (uint32_t)pTail, cPushes, (uint32_t)pTail->m_pNext, cPushes + 1);
        }
    }

跳跃是这样做的吗？我打赌。

于 2012-11-25T15:54:28.713 回答