哪里.NET将字符串值？ [英] Where does .NET place the String value?

问题描述

我使用SOS调试扩展DLL检查String类型的内存布局。而下面是结果。

I am using SOS debug extension dll to check the memory layout of a String type. And below is the result.

！DSO

ESP/REG  Object   Name

0015EFC0 01c6b9cc System.String    hello,world

！做01c6b9cc

Name:        System.String

MethodTable: 6de3f9ac

EEClass:     6db78bb0

Size:        36(0x24) bytes

File:        C:\Windows\Microsoft.Net\assembly\GAC_32\mscorlib\v4.0_4.0.0.0__b77a5c561934e089>\mscorlib.dll

String:      hello,world

Fields:
      MT    Field   Offset                 Type VT     Attr    Value Name

6de42978  40000ed        4         System.Int32  1 instance       11 m_stringLength

6de41dc8  40000ee        8          System.Char  1 instance       68 m_firstChar

6de3f9ac  40000ef        8        System.String  0   shared   static Empty

    >> Domain:Value  00331488:01c61228 <<

现在我想知道，到底是哪里的字符串值Hello World的存储？

Now I am wondering, where exactly is the string value "hello world" is stored?

感谢。

推荐答案

目前m_firstChar。堆分配足够大，以适应整个字符串，不只是第一个字符。易在Visual Studio中看到还有：

At m_firstChar. The heap allocation is large enough to fit the entire string, not just the first character. Easy to see in Visual Studio as well:

class Program {
    static void Main(string[] args) {
        string s = "hello" + "world";
    }  // <=== Breakpoint here
}

在断点命中，使用调试+的Windows +内存+内存1。在地址框中键入秒。你会看到：

When the breakpoint hits, use Debug + Windows + Memory + Memory1. In the Address box type s. You'll see:

0x01B3F6BC  e8 0a 67 6e 0b 00 00 00 0a 00 00 00 68 00 65 00  è.gn........h.e.
0x01B3F6CC  6c 00 6c 00 6f 00 77 00 6f 00 72 00 6c 00 64 00  l.l.o.w.o.r.l.d.

• 的对象开始在地址 - 4，syncblk被存储在那里（不可见）
。
• 在接下来的4个字节的方法表指针（0x6e670ae8，又名型手柄）。
• 在接下来的4个字节是m_arrayLength成员，该字符串（0x0B中）的分配大小。
• 接下来的4个字节是m_stringLength构件，字符的串（的0x0A）中的实际数目。
• 在接下来的字节存储字符串，起始于m_firstChar。
• The object starts at the address - 4, the syncblk is stored there (not visible).
• Next 4 bytes is the method table pointer (0x6e670ae8, aka type handle).
• Next 4 bytes is the m_arrayLength member, the allocated size of the string (0x0b).
• Next 4 bytes is the m_stringLength member, the actual number of characters in the string (0x0a).
• Next bytes store the string, starting at m_firstChar.

这是.NET 3.5 SP1。不知道为什么m_arrayLength成员是不是在你的输出中可见。

This is for .NET 3.5 SP1. Not sure why the m_arrayLength member isn't visible in your output.

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