C++如何在内存管理中追踪和分析内存使用情况

new

#include <iostream>
#include <map>
#include <string>
#include <mutex>
#include <new> // For std::bad_alloc
#include <vector> // For potential stack trace capture (simplified here)

// 定义一个结构体来存储每次分配的信息
struct AllocationInfo {
    size_t size;
    const char* file;
    int line;
    // 实际应用中，这里还可以添加时间戳、调用栈信息等
};

// 使用map来追踪所有活跃的内存分配
static std::map<void*, AllocationInfo> s_allocations;
static std::mutex s_mutex; // 保护map在多线程环境下的访问
static size_t s_current_memory_usage = 0;
static size_t s_peak_memory_usage = 0;

// 重载带文件和行号的new操作符
void* operator new(size_t size, const char* file, int line) {
    std::lock_guard<std::mutex> lock(s_mutex);
    void* ptr = std::malloc(size); // 使用C标准库的malloc进行实际分配
    if (!ptr) {
        throw std::bad_alloc(); // 分配失败抛出异常
    }
    s_allocations[ptr] = {size, file, line};
    s_current_memory_usage += size;
    if (s_current_memory_usage > s_peak_memory_usage) {
        s_peak_memory_usage = s_current_memory_usage;
    }
    // std::cout << "Allocated " << size << " bytes at " << ptr << " (" << file << ":" << line << ")\n";
    return ptr;
}

// 重载默认的new操作符，它会调用带文件和行号的版本
void* operator new(size_t size) {
    // 如果没有通过宏指定文件和行号，就用默认值
    return operator new(size, "<unknown>", 0);
}

// 重载delete操作符
void operator delete(void* ptr) noexcept {
    if (ptr == nullptr) return;

    std::lock_guard<std::mutex> lock(s_mutex);
    auto it = s_allocations.find(ptr);
    if (it != s_allocations.end()) {
        s_current_memory_usage -= it->second.size;
        // std::cout << "Deallocated " << it->second.size << " bytes at " << ptr << " (" << it->second.file << ":" << it->second.line << ")\n";
        s_allocations.erase(it);
    } else {
        // 尝试释放未被追踪的内存或已释放的内存，这通常是个bug
        std::cerr << "Warning: Attempting to delete untracked or already freed memory at " << ptr << "\n";
    }
    std::free(ptr); // 使用C标准库的free进行实际释放
}

// 同样需要重载 operator delete[]
void operator delete[](void* ptr) noexcept {
    operator delete(ptr); // 数组的delete通常可以委托给普通的delete
}

// 报告内存泄漏的函数
void ReportMemoryLeaks() {
    std::lock_guard<std::mutex> lock(s_mutex);
    if (!s_allocations.empty()) {
        std::cerr << "\n--- Memory Leaks Detected ---\n";
        for (const auto& pair : s_allocations) {
            std::cerr << "Leaked " << pair.second.size << " bytes at address " << pair.first
                      << " (allocated at " << pair.second.file << ":" << pair.second.line << ")\n";
        }
        std::cerr << "Total leaked bytes: " << s_current_memory_usage << "\n";
    } else {
        std::cout << "\nNo memory leaks detected.\n";
    }
    std::cout << "Peak memory usage during runtime: " << s_peak_memory_usage << " bytes.\n";
}

// 为了让所有new都自动带上文件和行号，可以在编译时使用宏
#define new new(__FILE__, __LINE__)

// 示例用法：
// 在main函数结束前调用 ReportMemoryLeaks();

ReportMemoryLeaks()

top

htop

new

delete

new

delete

delete

delete

new/delete

new/delete

new

delete

new/delete

-fsanitize=address

new

delete

delete

delete

new[]