和菜鸟一起深入学习国嵌实验之gcc分步编译&&gdb调试

gcc分步编译

 

1、编写简单例子

#include <stdio.h>
 
int main(void)
{
   printf("Hello!\n");
    return 0;
}

 

2、预处理生成hello.i

eastmoon@eastmoon-virtual-machine:~/work/guoqian/1/1.2$gcc -E hello.c -o hello.i
eastmoon@eastmoon-virtual-machine:~/work/guoqian/1/1.2$ls
hello.c hello.i

 

hello.i------à

…………………………
extern int pclose (FILE *__stream);
 
 
extern char *ctermid (char *__s) __attribute__((__nothrow__));
# 906 "/usr/include/stdio.h" 3 4
extern void flockfile (FILE *__stream)__attribute__ ((__nothrow__));
 
extern int ftrylockfile (FILE *__stream)__attribute__ ((__nothrow__)) ;
 
extern void funlockfile (FILE *__stream)__attribute__ ((__nothrow__));
# 936 "/usr/include/stdio.h" 3 4
 
# 2 "hello.c" 2
 
int main(void)
{
   printf("Hello!\n");
    return 0;
｝

 

2、生成汇编代码helloS

eastmoon@eastmoon-virtual-machine:~/work/guoqian/1/1.2$gcc -S hello.i -o hello.S
eastmoon@eastmoon-virtual-machine:~/work/guoqian/1/1.2$ls
hello.c hello.i  hello.S

 

hello.S----à

 

       .file  "hello.c"
       .section   .rodata
.LC0:
       .string     "Hello!"
       .text
.globl main
       .type       main, @function
main:
       pushl       %ebp
       movl       %esp, %ebp
       andl $-16, %esp
       subl $16, %esp
       movl       $.LC0, (%esp)
       call  puts
       movl       $0, %eax
       leave
       ret
       .size main, .-main
       .ident      "GCC: (Ubuntu/Linaro 4.5.2-8ubuntu4)4.5.2"
       .section   .note.GNU-stack,"",@progbits

 

3、编译汇编代码生成hello.o

eastmoon@eastmoon-virtual-machine:~/work/guoqian/1/1.2$gcc -c hello.c -o hello.o
eastmoon@eastmoon-virtual-machine:~/work/guoqian/1/1.2$ls
hello.c hello.i  hello.o  hello.S

 

4、链接，生成可执行文件hello

eastmoon@eastmoon-virtual-machine:~/work/guoqian/1/1.2$ls
hello hello.c  hello.i  hello.o hello.S

 

5、运行可执行文件，输出Hello！

eastmoon@eastmoon-virtual-machine:~/work/guoqian/1/1.2$./hello
Hello!
 

 

gdb调试

 

1、  测试代码编写

#include <stdio.h>
 
int add(int x, int y)
{
    return x+ y;
}
 
int main(void)
{
    int a, b;
   
    a = 4;
    b = 5;
   
    a =add(a, b);
 
   printf("a+b = %d\n", a);
 
    return 0;
}

 

2、编译代码生成可执行文件add

eastmoon@eastmoon-virtual-machine:~/work/guoqian/1/1.3$gcc -g add.c -o add
eastmoon@eastmoon-virtual-machine:~/work/guoqian/1/1.3$ls
add  add.c

 

3、进入gdb调试

eastmoon@eastmoon-virtual-machine:~/work/guoqian/1/1.3$gdb add
GNU gdb (Ubuntu/Linaro 7.2-1ubuntu11) 7.2
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later<http://gnu.org/licenses/gpl.html>
This is free software: you are free to change andredistribute it.
There is NO WARRANTY, to the extent permitted bylaw.  Type "show copying"
and "show warranty" for details.
This GDB was configured as"i686-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /home/eastmoon/work/guoqian/1/1.3/add...done.
(gdb)

 

4、查看文件

(gdb) l
    3   int add(int x, int y)
    4   {
       5       return x + y;
       6   }
       7  
       8   int main(void)
    9   {
       10      int a, b;
       11     
           12      a = 4;
        (gdb)
           13      b = 5;
       14     
           15      a = add(a, b);
       16 
           17      printf("a+b =%d\n", a);
       18 
            19      return 0;
       20  }
       21 

 

5、设置断点

(gdb) b 15
Breakpoint 1 at 0x80483eb: file add.c, line 15.
 

6、查看断点信息

(gdb) info b
Num    Type           Disp EnbAddress    What
1      breakpoint     keep y   0x080483eb in main at add.c:15
 

7、运行代码

(gdb) r
Starting program:/home/eastmoon/work/guoqian/1/1.3/add
 
Breakpoint 1, main () at add.c:15
15      a =add(a, b);
 

8、查看变量值

(gdb) p a
$1 = 4
(gdb) p b
$2 = 5

 

9、单步运行，可进入函数

(gdb) s
add (x=4, y=5) at add.c:5
5      return x + y;
(gdb) s
6   }
(gdb) s
main () at add.c:17
17     printf("a+b = %d\n", a);
 
(gdb) p a
$3 = 9
(gdb) p b
$4 = 5

 

10、单步运行，不可进入函数

(gdb) n
a+b = 9
19     return 0;

 

11、运行程序，直到函数结束

(gdb) finish
"finish" not meaningful in the outermostframe.
 

12、恢复程序运行

(gdb) c
Continuing.
 
Program exited normally.
 

13、退出gdb调试

(gdb) q