批评我的堆调试器 [英] Critique my heap debugger

问题描述

我写了下面的堆调试器，以演示内存泄漏，双删除和错误形式的删除（即试图删除一个数组 delete p 而不是<$

I wrote the following heap debugger in order to demonstrate memory leaks, double deletes and wrong forms of deletes (i.e. trying to delete an array with delete p instead of delete[] p) to beginning programmers.

我想从强大的C ++程序员那里得到一些反馈，因为I从来没有这样做过，我相信我做了一些愚蠢的错误。谢谢！

I would love to get some feedback on that from strong C++ programmers because I have never done this before and I'm sure I've done some stupid mistakes. Thanks!

#include <cstdlib>
#include <iostream>
#include <new>

namespace
{
    const int ALIGNMENT = 16;
    const char* const ERR = "*** ERROR: ";
    int counter = 0;

    struct heap_debugger
    {
        heap_debugger()
        {
            std::cerr << "*** heap debugger started\n";
        }

        ~heap_debugger()
        {
            std::cerr << "*** heap debugger shutting down\n";
            if (counter > 0)
            {
                std::cerr << ERR << "failed to release memory " << counter << " times\n";
            }
            else if (counter < 0)
            {
                std::cerr << ERR << (-counter) << " double deletes detected\n";
            }
        }
    } instance;

    void* allocate(size_t size, const char* kind_of_memory, size_t token) throw (std::bad_alloc)
    {
        void* raw = malloc(size + ALIGNMENT);
        if (raw == 0) throw std::bad_alloc();

        *static_cast<size_t*>(raw) = token;
        void* payload = static_cast<char*>(raw) + ALIGNMENT;

        ++counter;
        std::cerr << "*** allocated " << kind_of_memory << " at " << payload << " (" << size << " bytes)\n";
        return payload;
    }

    void release(void* payload, const char* kind_of_memory, size_t correct_token, size_t wrong_token) throw ()
    {
        if (payload == 0) return;

        std::cerr << "*** releasing " << kind_of_memory << " at " << payload << '\n';
        --counter;

        void* raw = static_cast<char*>(payload) - ALIGNMENT;
        size_t* token = static_cast<size_t*>(raw);

        if (*token == correct_token)
        {
            *token = 0xDEADBEEF;
            free(raw);
        }
        else if (*token == wrong_token)
        {
            *token = 0x177E6A7;
            std::cerr << ERR << "wrong form of delete\n";
        }
        else
        {
            std::cerr << ERR << "double delete\n";
        }
    }
}

void* operator new(size_t size) throw (std::bad_alloc)
{
    return allocate(size, "non-array memory", 0x5AFE6A8D);
}

void* operator new[](size_t size) throw (std::bad_alloc)
{
    return allocate(size, "    array memory", 0x5AFE6A8E);
}

void operator delete(void* payload) throw ()
{
    release(payload, "non-array memory", 0x5AFE6A8D, 0x5AFE6A8E);
}

void operator delete[](void* payload) throw ()
{
    release(payload, "    array memory", 0x5AFE6A8E, 0x5AFE6A8D);
}

推荐答案

保持您可以保留所有分配的列表。然后，您可以释放内存而不破坏您自己的数据，并跟踪特定地址被删除的次数，还可以找到程序尝试删除不匹配地址的位置（即不在列表中）。

Instead of doing intrusive note-keeping you could keep a list of all allocations made. Then you can free the memory without destroying your own data, and keep track of how many times a particular address is "deleted", and also find places where the program tries to delete a non-matching address (i.e. not in the list).

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