堆栈平衡

  1 #include <stdio.h>
  2 #include <unistd.h>
  3 
  4 int  abc() {
  5         int d;
  6         return 2;
  7 }
  8 int  sum(int a) {
  9         int c;
 10         abc();
 11         return a;
 12 }
 13 int main() {
 14         int b = 0;
 15         b = sum(1);
 16         printf("hello:%d\n", b);
 17         return 0;
 18 }




  1         .file   "test.c"
  2         .text
  3         .globl  abc
  4         .type   abc, @function
  5 abc:
  6         pushq   %rbp
  7         movq    %rsp, %rbp
  8         movl    $2, %eax
  9         popq    %rbp
 10         ret
 11         .size   abc, .-abc
 12         .globl  sum
 13         .type   sum, @function
 14 sum:
 15         pushq   %rbp
 16         movq    %rsp, %rbp
 17         subq    $8, %rsp
 18         movl    %edi, -4(%rbp)
 19         movl    $0, %eax
 20         call    abc
 21         movl    -4(%rbp), %eax
 22         leave
 23         ret
 24         .size   sum, .-sum
 25         .section        .rodata
 26 .LC0:
 27         .string "hello:%d\n"
 28         .text
 29         .globl  main
 30         .type   main, @function
 31 main:
 32         pushq   %rbp
 33         movq    %rsp, %rbp
 34         subq    $16, %rsp
 35         movl    $0, -4(%rbp)
 36         movl    $1, %edi
 37         call    sum
 38         movl    %eax, -4(%rbp)
 39         movl    -4(%rbp), %eax
 40         movl    %eax, %esi
 41         movl    $.LC0, %edi
 42         movl    $0, %eax
 43         call    printf
 44         movl    $0, %eax
 45         leave
 46         ret
 47         .size   main, .-main
 48         .ident  "GCC: (Ubuntu 5.4.0-6ubuntu1~16.04.1) 5.4.0 20160609"
 49         .section        .note.GNU-stack,"",@progbits
                                     

https://blog.csdn.net/kingzone_2008/article/details/44544285

分析一下堆帧：

 1.call main 初始化：

 

 

 

2. main  

 pushq   %rbp    //会使rsp=rsp+4  存入调用main 之前的栈帧

 movq    %rsp, %rbp

 

 

 

3.分配临时变量

 subq    $16, %rsp

 movl    $0, -4(%rbp)

 movl    $1, %edi

 call    sum

 

 

 

4. sum

pushq %rbp         //存入调用main 的栈帧

movq %rsp, %rbp 

 

 

5. 

subq $8, %rsp

call abc

pushq   %rbp

movq    %rsp, %rbp

 

 

 

 

6. abc 回退栈帧

popq %rbp

ret 

 

 

7 回退sum

leave 

ret 

 

 

 

8 回退main