VB.NET并行与分布式编程(四)-线程栈[1]

VB.NET并行与分布式编程(4)-线程栈[1]

1、用调试器调试线程

?1)栈调用

以下面代码为例

Imports System.ThreadingPublic Class Form1    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click        Dim main_x As Integer        main_x = 5        Call sub1(main_x)    End Sub    Private Sub sub1(sub1_x As Integer)        Dim jg As Integer        jg = sub1_x * sub1_x        Call sub2(jg)    End Sub    Private Sub sub2(sub2_x As Integer)        Dim jg As Integer        jg = sub2_x * 2        '在下一句设置断点        jg = jg * jg    End SubEnd Class

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?我们首先来看调用堆栈，在调试菜单中选择调用堆栈,可看到过程的调用顺序：

?然后查看线程

?最后查看局部变量

?此外，我们还可以研究一下这个线程的调用时堆栈情况，通过反汇编代码,在调用堆栈窗口中选择“转到反汇编”

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   Private Sub sub2(sub2_x As Integer)00000000  push        ebp 00000001  mov         ebp,esp 00000003  sub         esp,14h 00000006  mov         dword ptr [ebp-10h],ecx 00000009  mov         dword ptr [ebp-4],edx 0000000c  cmp         dword ptr ds:[0256B1B8h],0 00000013  je          0000001A 00000015  call        62A16743 0000001a  xor         edx,edx 0000001c  mov         dword ptr [ebp-8],edx 0000001f  mov         eax,dword ptr [ebp-10h] 00000022  mov         dword ptr [ebp-14h],eax 00000025  mov         ecx,dword ptr [ebp-10h] 00000028  call        628F5C25 0000002d  mov         dword ptr [ebp-0Ch],eax 00000030  push        32h 00000032  mov         edx,dword ptr [ebp-0Ch] 00000035  mov         ecx,dword ptr [ebp-14h] 00000038  call        FFDF30D0 0000003d  mov         ecx,dword ptr [ebp-4] 00000040  call        FFFFFF70 00000045  mov         ecx,63h 0000004a  call        FFDF2940 0000004f  nop         Dim jg As Integer        jg = sub2_x * 200000050  mov         eax,dword ptr [ebp-4] 00000053  mov         edx,2 00000058  imul        eax,eax,2 0000005b  jno         00000062 0000005d  call        62A19A30 00000062  mov         dword ptr [ebp-8],eax         '在下一句设置断点        jg = jg * jg00000065  mov         eax,dword ptr [ebp-8] 00000068  imul        eax,dword ptr [ebp-8] 0000006c  jno         00000073 0000006e  call        62A19A30 00000073  mov         dword ptr [ebp-8],eax     End Sub00000076  nop 00000077  nop 00000078  mov         ecx,63h 0000007d  call        FFDF2A60 00000082  nop 00000083  mov         esp,ebp 00000085  pop         ebp 00000086  ret 

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ESP是栈顶指针

ebp是基址指针

+-----+

+基址 +

+-----+

+栈内容+

+栈内容+

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+栈内容+

+栈内容+

+栈内容+

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+栈顶?? +

如上图所示，基地的地址比栈顶的地址大，就是向下增长。

寄存器ebp和esp保存着当前的基址和栈顶地址

首先，进入函数时

00000000? push??????? ebp
备份基址指针

00000001? mov???????? ebp,esp

然后设置基址指针指向栈顶，相当于为当前栈清空了内容，做好在栈中分配局部变量的准备
00000003? sub???????? esp,14h

完成栈（可以理解为本函数可访问的栈）的空间分配，将栈顶指针向下增长14h(向下增长的意思是栈的空间增长规律是地址递减)。相当于栈中已经容纳了14h的空间

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??????? Dim jg As Integer
??????? jg = sub2_x * 2
00000050? mov???????? eax,dword ptr [ebp-4]
00000053? mov???????? edx,2
00000058? imul??????? eax,eax,2
0000005b? jno???????? 00000062
0000005d? call??????? 617391D0
00000062? mov???????? dword ptr [ebp-8],eax
??????? '在下一句设置断点
??????? jg = jg * jg
00000065? mov???????? eax,dword ptr [ebp-8]
00000068? imul??????? eax,dword ptr [ebp-8]
0000006c? jno???????? 00000073
0000006e? call??????? 617391D0
00000073? mov???????? dword ptr [ebp-8],eax

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从上面这段代码可以看出来

sub2_x分配在了dword ptr [ebp-4] ，而jg分配在了dword ptr [ebp-8]

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最后，离开函数时，恢复进入函数前栈的指针，相当于释放了本次在栈中分配的空间

??? End Sub
00000083? mov???????? esp,ebp
恢复栈顶指针

00000085? pop???????? ebp

恢复基址指针

00000086? ret

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2、修改默认栈的大小

???????? Dim?线程变量名 As Thread = New Thread(函数名,以字节为单位的栈大小)

比如

??????? Dim mythread As Thread = New Thread(myfun,1024*512)

分配了512kb字节

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