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【Visual Leak Detector】配置项 StackWalkMethod

  • Post category:C++

说明

使用 VLD 内存泄漏检测工具辅助开发时整理的学习笔记。本篇介绍 VLD 配置文件中配置项 StackWalkMethod 的使用方法。同系列文章目录可见 《内存泄漏检测工具》目录

目录

1. 配置文件使用说明

在程序中通过 #include "vld.h" 的方式检测内存泄漏时，VLD 首先会尝试在程序的生成目录下读取 vld.ini 文件，若未读取成功，则会尝试在 VLD 的安装目录下读取 vld.ini 文件，若仍未读取成功，则会使用内置的默认配置，内置的默认配置如果不动源码是无法更改的，因此通过修改相应目录下的 vld.ini 文件来定制 VLD 功能是最好的选择。当配置参数等号右边为空，或者给配置了不合法值时，在使用过程中会被程序重置到默认值。

2. 设置调用堆栈的跟踪方法

参数名：StackWalkMethod。

有效赋值：fast，safe。

默认值：fast。

功能说明：设置调用堆栈的跟踪方法。fast 方法速度快但跟踪的调用堆栈可能不完整，会漏掉一些；safe 方法能更可靠地获得完整的调用堆栈，但速度会慢很多，有可能导致被检测的程序性能出现显著下降，这时为了减少检测时间，可以将配置项 MaxTraceFrames 设置得小一些。

2.1 测试代码

#include <QCoreApplication>
#include <QDebug>
#include <QTime>
#include "vld.h"

void testFun(int i)
{
    if (i > 1)
    {
        testFun(i-1);
    }else
    {
        int *ptr = new int(i);
        printf("ptr = %08x, *ptr = %08x.\n", ptr, *ptr);
    }
}

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    QTime timedebuge;

    timedebuge.start();
    testFun(30);
    qDebug() << "Elapsed Time: " << timedebuge.elapsed() << "ms";

    return a.exec();
}

测试环境：QT 5.9.2，MSVC 2015 32bit，Debug 模式，VLD 版本为 2.5.1，VLD 配置文件只对该参数做修改，测试工程所在路径为：E:\Cworkspace\Qt 5.9\QtDemo\testVLD。

2.2 StackWalkMethod = fast 时的输出

标准输出窗显示：

ptr = 006e90c0, *ptr = 00000001.
Elapsed Time:  1 ms

VLD 输出报告：

Visual Leak Detector read settings from: D:\Program Files (x86)\Visual Leak Detector\vld.ini
Visual Leak Detector Version 2.5.1 installed.
WARNING: Visual Leak Detector detected memory leaks!
---------- Block 1 at 0x006E90C0: 4 bytes ----------
  Leak Hash: 0x03496A17, Count: 1, Total 4 bytes
  Call Stack (TID 11760):
    ucrtbased.dll!malloc()
    f:\dd\vctools\crt\vcstartup\src\heap\new_scalar.cpp (19): testVLD.exe!operator new() + 0x9 bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (13): testVLD.exe!testFun() + 0x7 bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (25): testVLD.exe!main() + 0x7 bytes
    f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl (74): testVLD.exe!invoke_main() + 0x1B bytes
    f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl (264): testVLD.exe!__scrt_common_main_seh() + 0x5 bytes
    f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl (309): testVLD.exe!__scrt_common_main()
    f:\dd\vctools\crt\vcstartup\src\startup\exe_main.cpp (17): testVLD.exe!mainCRTStartup()
    KERNEL32.DLL!BaseThreadInitThunk() + 0x19 bytes
    ntdll.dll!RtlGetAppContainerNamedObjectPath() + 0x11E bytes
    ntdll.dll!RtlGetAppContainerNamedObjectPath() + 0xEE bytes
  Data:
    01 00 00 00                                                  ........ ........


Visual Leak Detector detected 1 memory leak (40 bytes).
Largest number used: 40 bytes.
Total allocations: 40 bytes.
Visual Leak Detector is now exiting.

2.3 StackWalkMethod = safe 时的输出

标准输出窗显示：

ptr = 012aa388, *ptr = 00000001.
Elapsed Time:  18 ms

VLD 输出报告：

Visual Leak Detector read settings from: D:\Program Files (x86)\Visual Leak Detector\vld.ini
Visual Leak Detector Version 2.5.1 installed.
    Using the "safe" (but slow) stack walking method.
WARNING: Visual Leak Detector detected memory leaks!
---------- Block 1 at 0x012AA388: 4 bytes ----------
  Leak Hash: 0x9281F97B, Count: 1, Total 4 bytes
  Call Stack (TID 30696):
    ucrtbased.dll!malloc()
    f:\dd\vctools\crt\vcstartup\src\heap\new_scalar.cpp (19): testVLD.exe!operator new() + 0x9 bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (13): testVLD.exe!testFun() + 0x7 bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (10): testVLD.exe!testFun() + 0xC bytes
    e:\cworkspace\qt 5.9\qtdemo\testvld\main.cpp (25): testVLD.exe!main() + 0x7 bytes
    f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl (74): testVLD.exe!invoke_main() + 0x1B bytes
    f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl (264): testVLD.exe!__scrt_common_main_seh() + 0x5 bytes
    f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl (309): testVLD.exe!__scrt_common_main()
    f:\dd\vctools\crt\vcstartup\src\startup\exe_main.cpp (17): testVLD.exe!mainCRTStartup()
    KERNEL32.DLL!BaseThreadInitThunk() + 0x19 bytes
    ntdll.dll!RtlGetAppContainerNamedObjectPath() + 0x11E bytes
    ntdll.dll!RtlGetAppContainerNamedObjectPath() + 0xEE bytes
  Data:
    01 00 00 00                                                  ........ ........


Visual Leak Detector detected 1 memory leak (40 bytes).
Largest number used: 40 bytes.
Total allocations: 40 bytes.
Visual Leak Detector is now exiting.

2.4 输出结果对比

  • 当 StackWalkMethod = fast 时，耗时 1 ms，此次检测输出了全部的调用堆栈。
  • 当 StackWalkMethod = safe 时，耗时 18 ms，也检测输出了全部的调用堆栈。
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