c语言的堆栈

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#语言 #c #function #汇编

本文详细解析了一个包含三个函数（h、f、main）的C++程序，展示了函数调用过程中的栈操作，包括参数传递、局部变量初始化、返回值处理等关键步骤。通过汇编代码的展示，读者可以深入了解C++中函数调用时的内存栈变化，对于理解底层内存管理和函数执行机制有重要帮助。

int h(int x1, int x2)

{
int h1 = 1;
int h2 = x1+x2;
return h2;
}

void f()
{
int f1 = 1;
int f2=f1+1;
h(1, 2);
}

int main()
{
int m = 5;
f();
return 0;
}

(gdb) disassemble h
Dump of assembler code for function h(int, int):
0x08048404 <+0>: push %ebp #保存上层栈的ebp
0x08048405 <+1>: mov %esp,%ebp #上层栈的esp+8,eip和刚刚保存的ebp
0x08048407 <+3>: sub $0x10,%esp #本层栈的增长,想下增长,就是减了
0x0804840a <+6>: movl $0x1,-0x8(%ebp) #h1=1
0x08048411 <+13>: mov 0xc(%ebp),%eax #x2, eax寄存器是不会压栈的,总是这个函数里给eax赋初始值后才使用.
0x08048414 <+16>: add 0x8(%ebp),%eax #x1+x2
0x08048417 <+19>: mov %eax,-0x4(%ebp) #得到h2
0x0804841a <+22>: mov -0x4(%ebp),%eax
0x0804841d <+25>: leave
0x0804841e <+26>: ret
End of assembler dump.

(gdb) disassemble f
Dump of assembler code for function f():
0x08048420 <+0>: push %ebp
0x08048421 <+1>: mov %esp,%ebp
0x08048423 <+3>: sub $0x18,%esp
0x08048426 <+6>: movl $0x1,-0x8(%ebp)
0x0804842d <+13>: mov -0x8(%ebp),%eax
0x08048430 <+16>: add $0x1,%eax
0x08048433 <+19>: mov %eax,-0x4(%ebp)
0x08048436 <+22>: movl $0x2,0x4(%esp)
0x0804843e <+30>: movl $0x1,(%esp)
0x08048445 <+37>: call 0x8048404 <h(int, int)>
0x0804844a <+42>: leave
0x0804844b <+43>: ret
End of assembler dump.

(gdb) disassemble main

Dump of assembler code for function main():
0x0804844c <+0>: lea 0x4(%esp),%ecx
0x08048450 <+4>: and $0xfffffff0,%esp
0x08048453 <+7>: pushl -0x4(%ecx)
0x08048456 <+10>: push %ebp
0x08048457 <+11>: mov %esp,%ebp
0x08048459 <+13>: push %ecx
0x0804845a <+14>: sub $0x10,%esp
0x0804845d <+17>: movl $0x5,-0x8(%ebp)
0x08048464 <+24>: call 0x8048420 <f()>
0x08048469 <+29>: mov $0x0,%eax
0x0804846e <+34>: add $0x10,%esp
0x08048471 <+37>: pop %ecx
0x08048472 <+38>: pop %ebp
0x08048473 <+39>: lea -0x4(%ecx),%esp
0x08048476 <+42>: ret
End of assembler dump.