单步指令区别step next stepi nexti

代码验证:
龙芯3A5000验证
$ cat test.c
#include<stdio.h>
int  add ( int d1, int d2 )
{
  int d;
  d = d1 + 1;
  d = d + d2 + 2;
  return d;
}

int  add1 ( int d1, int d2 )
{
  int d;
  d = d1 + 10;
  d = d + d2 + 20;
  return d;
}

int main()
{
   int a = 0, b = 0;
   a = b + 1;
   a = add(a, b);
   a = a + 10;
   b = add1(a, b);
   b = a + b; 
   return 1; 
}
桌面20.3系统
lihui@lihui-pc:~/community/build$ gcc -v

gcc version 8.3.0 (Loongnix 8.3.0-6.lnd.vec.33) 

lihui@lihui-pc:~/community/build$ gdb/gdb -v

GNU gdb (GDB) 14.0.50.20230705-git



lihui@lihui-pc:~/community/build$ gcc -g test.c -o test
lihui@lihui-pc:~/community/build$ objdump -d test

00000001200006d0 <add>:
   1200006d0:	02ff4063 	addi.d	$r3,$r3,-48(0xfd0)
   1200006d4:	29c0a076 	st.d	$r22,$r3,40(0x28)
   1200006d8:	02c0c076 	addi.d	$r22,$r3,48(0x30)
   1200006dc:	0015008d 	move	$r13,$r4
   1200006e0:	001500ac 	move	$r12,$r5
   1200006e4:	004081ad 	slli.w	$r13,$r13,0x0
   1200006e8:	29bf72cd 	st.w	$r13,$r22,-36(0xfdc)
   1200006ec:	0040818c 	slli.w	$r12,$r12,0x0
   1200006f0:	29bf62cc 	st.w	$r12,$r22,-40(0xfd8)
   1200006f4:	28bf72cc 	ld.w	$r12,$r22,-36(0xfdc)
   1200006f8:	0280058c 	addi.w	$r12,$r12,1(0x1)
   1200006fc:	29bfb2cc 	st.w	$r12,$r22,-20(0xfec)
   120000700:	28bfb2cd 	ld.w	$r13,$r22,-20(0xfec)
   120000704:	28bf62cc 	ld.w	$r12,$r22,-40(0xfd8)
   120000708:	001031ac 	add.w	$r12,$r13,$r12
   12000070c:	0280098c 	addi.w	$r12,$r12,2(0x2)
   120000710:	29bfb2cc 	st.w	$r12,$r22,-20(0xfec)
   120000714:	28bfb2cc 	ld.w	$r12,$r22,-20(0xfec)
   120000718:	00150184 	move	$r4,$r12
   12000071c:	28c0a076 	ld.d	$r22,$r3,40(0x28)
   120000720:	02c0c063 	addi.d	$r3,$r3,48(0x30)
   120000724:	4c000020 	jirl	$r0,$r1,0

0000000120000728 <add1>:
   120000728:	02ff4063 	addi.d	$r3,$r3,-48(0xfd0)
   12000072c:	29c0a076 	st.d	$r22,$r3,40(0x28)
   120000730:	02c0c076 	addi.d	$r22,$r3,48(0x30)
   120000734:	0015008d 	move	$r13,$r4
   120000738:	001500ac 	move	$r12,$r5
   12000073c:	004081ad 	slli.w	$r13,$r13,0x0
   120000740:	29bf72cd 	st.w	$r13,$r22,-36(0xfdc)
   120000744:	0040818c 	slli.w	$r12,$r12,0x0
   120000748:	29bf62cc 	st.w	$r12,$r22,-40(0xfd8)
   12000074c:	28bf72cc 	ld.w	$r12,$r22,-36(0xfdc)
   120000750:	0280298c 	addi.w	$r12,$r12,10(0xa)
   120000754:	29bfb2cc 	st.w	$r12,$r22,-20(0xfec)
   120000758:	28bfb2cd 	ld.w	$r13,$r22,-20(0xfec)
   12000075c:	28bf62cc 	ld.w	$r12,$r22,-40(0xfd8)
   120000760:	001031ac 	add.w	$r12,$r13,$r12
   120000764:	0280518c 	addi.w	$r12,$r12,20(0x14)
   120000768:	29bfb2cc 	st.w	$r12,$r22,-20(0xfec)
   12000076c:	28bfb2cc 	ld.w	$r12,$r22,-20(0xfec)
   120000770:	00150184 	move	$r4,$r12
   120000774:	28c0a076 	ld.d	$r22,$r3,40(0x28)
   120000778:	02c0c063 	addi.d	$r3,$r3,48(0x30)
   12000077c:	4c000020 	jirl	$r0,$r1,0

0000000120000780 <main>:
   120000780:	02ff8063 	addi.d	$r3,$r3,-32(0xfe0)
   120000784:	29c06061 	st.d	$r1,$r3,24(0x18)
   120000788:	29c04076 	st.d	$r22,$r3,16(0x10)
   12000078c:	02c08076 	addi.d	$r22,$r3,32(0x20)
   120000790:	29bfb2c0 	st.w	$r0,$r22,-20(0xfec)
   120000794:	29bfa2c0 	st.w	$r0,$r22,-24(0xfe8)
   120000798:	28bfa2cc 	ld.w	$r12,$r22,-24(0xfe8)
   12000079c:	0280058c 	addi.w	$r12,$r12,1(0x1)
   1200007a0:	29bfb2cc 	st.w	$r12,$r22,-20(0xfec)
   1200007a4:	28bfa2cd 	ld.w	$r13,$r22,-24(0xfe8)
   1200007a8:	28bfb2cc 	ld.w	$r12,$r22,-20(0xfec)
   1200007ac:	001501a5 	move	$r5,$r13
   1200007b0:	00150184 	move	$r4,$r12
   1200007b4:	57ff1fff 	bl	-228(0xfffff1c) # 1200006d0 <add>
   1200007b8:	0015008c 	move	$r12,$r4
   1200007bc:	29bfb2cc 	st.w	$r12,$r22,-20(0xfec)
   1200007c0:	28bfb2cc 	ld.w	$r12,$r22,-20(0xfec)
   1200007c4:	0280298c 	addi.w	$r12,$r12,10(0xa)
   1200007c8:	29bfb2cc 	st.w	$r12,$r22,-20(0xfec)
   1200007cc:	28bfa2cd 	ld.w	$r13,$r22,-24(0xfe8)
   1200007d0:	28bfb2cc 	ld.w	$r12,$r22,-20(0xfec)
   1200007d4:	001501a5 	move	$r5,$r13
   1200007d8:	00150184 	move	$r4,$r12
   1200007dc:	57ff4fff 	bl	-180(0xfffff4c) # 120000728 <add1>
   1200007e0:	0015008c 	move	$r12,$r4
   1200007e4:	29bfa2cc 	st.w	$r12,$r22,-24(0xfe8)
   1200007e8:	28bfa2cd 	ld.w	$r13,$r22,-24(0xfe8)
   1200007ec:	28bfb2cc 	ld.w	$r12,$r22,-20(0xfec)
   1200007f0:	001031ac 	add.w	$r12,$r13,$r12
   1200007f4:	29bfa2cc 	st.w	$r12,$r22,-24(0xfe8)
   1200007f8:	0280040c 	addi.w	$r12,$r0,1(0x1)
   1200007fc:	00150184 	move	$r4,$r12
   120000800:	28c06061 	ld.d	$r1,$r3,24(0x18)
   120000804:	28c04076 	ld.d	$r22,$r3,16(0x10)
   120000808:	02c08063 	addi.d	$r3,$r3,32(0x20)
   12000080c:	4c000020 	jirl	$r0,$r1,0



验证next

lihui@lihui-pc:~/community/build$ gdb/gdb test
...
(gdb) start
Temporary breakpoint 1 at 0x120000790: file test.c, line 20.
Starting program: /home/lihui/community/build/test 

Temporary breakpoint 1, main () at test.c:20
20	   int a = 0, b = 0;
(gdb) l
15	  return d;
16	}
17	
18	int main()
19	{
20	   int a = 0, b = 0;
21	   a = b + 1;
22	   a = add(a, b);
23	   a = a + 10;
24	   b = add1(a, b);
(gdb) next
21	   a = b + 1;
(gdb) next
22	   a = add(a, b);
(gdb) next
23	   a = a + 10;
(gdb) next
24	   b = add1(a, b);
(gdb) next
25	   b = a + b; 
(gdb) next
26	   return 1; 
(gdb) next
27	}
...


验证step

lihui@lihui-pc:~/community/build$ gdb/gdb test
...
(gdb) start
..
Temporary breakpoint 1, main () at test.c:20
20	   int a = 0, b = 0;
(gdb) step
21	   a = b + 1;
(gdb) step
22	   a = add(a, b);
(gdb) step
add (d1=1, d2=0) at test.c:5
5	  d = d1 + 1;
(gdb) step
6	  d = d + d2 + 2;
(gdb) step
7	  return d;
(gdb) step
8	}
(gdb) step
main () at test.c:23
23	   a = a + 10;
(gdb) step
24	   b = add1(a, b);
(gdb) step
add1 (d1=14, d2=0) at test.c:13
13	  d = d1 + 10;
(gdb) step
14	  d = d + d2 + 20;
(gdb) step
15	  return d;
(gdb) step
16	}
(gdb) step
main () at test.c:25
25	   b = a + b; 
(gdb) step
26	   return 1; 
(gdb) step
27	}


可以看到next命令遇到函数不进入，step遇到函数进入，符合预期。

验证nexti 

lihui@lihui-pc:~/community/build$ gdb/gdb test
...
(gdb) start
Temporary breakpoint 1 at 0x120000790: file test.c, line 20.
Starting program: /home/lihui/community/build/test 

Temporary breakpoint 1, main () at test.c:20
20	   int a = 0, b = 0;
(gdb) nexti
20	   int a = 0, b = 0;
(gdb) nexti
21	   a = b + 1;
(gdb) nexti
0x000000012000079c	21	   a = b + 1;
(gdb) nexti
0x00000001200007a0	21	   a = b + 1;
(gdb) nexti
22	   a = add(a, b);
(gdb) nexti
0x00000001200007a8	22	   a = add(a, b);
(gdb) nexti
0x00000001200007ac	22	   a = add(a, b);
(gdb) nexti
0x00000001200007b0	22	   a = add(a, b);
(gdb) nexti
0x00000001200007b4	22	   a = add(a, b);
(gdb) nexti
0x00000001200007b8	22	   a = add(a, b);
(gdb) nexti
0x00000001200007bc	22	   a = add(a, b);
(gdb) nexti
23	   a = a + 10;
(gdb) nexti
0x00000001200007c4	23	   a = a + 10;
(gdb) nexti
0x00000001200007c8	23	   a = a + 10;
(gdb) nexti
24	   b = add1(a, b);
(gdb) nexti
0x00000001200007d0	24	   b = add1(a, b);
(gdb) nexti
0x00000001200007d4	24	   b = add1(a, b);
(gdb) nexti
0x00000001200007d8	24	   b = add1(a, b);
(gdb) nexti
0x00000001200007dc	24	   b = add1(a, b);
(gdb) nexti
0x00000001200007e0	24	   b = add1(a, b);
(gdb) nexti
0x00000001200007e4	24	   b = add1(a, b);
(gdb) nexti
25	   b = a + b; 
(gdb) nexti
0x00000001200007ec	25	   b = a + b; 
(gdb) nexti
0x00000001200007f0	25	   b = a + b; 
(gdb) nexti
0x00000001200007f4	25	   b = a + b; 
(gdb) nexti
26	   return 1; 
(gdb) nexti
27	}

nexti是逐条指令执行，但是没有进入到add和add1函数，跳过了这两个函数继续执行下面的指令。


验证stepi
lihui@lihui-pc:~/community/build$ gdb/gdb test
...
(gdb) start
Temporary breakpoint 1 at 0x120000790: file test.c, line 20.
Starting program: /home/lihui/community/build/test 

Temporary breakpoint 1, main () at test.c:20
20	   int a = 0, b = 0;
(gdb) next
21	   a = b + 1;
(gdb) next
22	   a = add(a, b);
(gdb) stepi
0x00000001200007a8	22	   a = add(a, b);
(gdb) stepi
0x00000001200007ac	22	   a = add(a, b);
(gdb) stepi
0x00000001200007b0	22	   a = add(a, b);
(gdb) stepi
0x00000001200007b4	22	   a = add(a, b);
(gdb) stepi
add (d1=0, d2=0) at test.c:3
3	{
(gdb) stepi
0x00000001200006d4	3	{
(gdb) stepi
0x00000001200006d8	3	{
(gdb) stepi
0x00000001200006dc	3	{
(gdb) stepi
0x00000001200006e0	3	{
(gdb) stepi
0x00000001200006e4	3	{
(gdb) stepi
0x00000001200006e8	3	{
(gdb) stepi
0x00000001200006ec	3	{
(gdb) stepi
0x00000001200006f0	3	{
(gdb) stepi
5	  d = d1 + 1;
(gdb) stepi
0x00000001200006f8	5	  d = d1 + 1;
(gdb) stepi
0x00000001200006fc	5	  d = d1 + 1;
(gdb) stepi
6	  d = d + d2 + 2;
(gdb) stepi
0x0000000120000704	6	  d = d + d2 + 2;
(gdb) stepi
0x0000000120000708	6	  d = d + d2 + 2;
(gdb) stepi
6	  d = d + d2 + 2;
(gdb) stepi
0x0000000120000710	6	  d = d + d2 + 2;
(gdb) stepi
7	  return d;
(gdb) stepi
8	}
(gdb) next
main () at test.c:23
23	   a = a + 10;
(gdb) next
24	   b = add1(a, b);
(gdb) stepi
0x00000001200007d0	24	   b = add1(a, b);
(gdb) stepi
0x00000001200007d4	24	   b = add1(a, b);
(gdb) stepi
0x00000001200007d8	24	   b = add1(a, b);
(gdb) stepi
0x00000001200007dc	24	   b = add1(a, b);
(gdb) stepi
add1 (d1=1, d2=0) at test.c:11
11	{
(gdb) stepi
0x000000012000072c	11	{
(gdb) stepi
0x0000000120000730	11	{
(gdb) stepi
0x0000000120000734	11	{
(gdb) stepi
0x0000000120000738	11	{
(gdb) stepi
0x000000012000073c	11	{
(gdb) stepi
0x0000000120000740	11	{
(gdb) stepi
0x0000000120000744	11	{
(gdb) stepi
0x0000000120000748	11	{
(gdb) stepi
13	  d = d1 + 10;
(gdb) stepi
0x0000000120000750	13	  d = d1 + 10;
(gdb) stepi
0x0000000120000754	13	  d = d1 + 10;
(gdb) stepi
14	  d = d + d2 + 20;
(gdb) stepi
0x000000012000075c	14	  d = d + d2 + 20;
(gdb) stepi
0x0000000120000760	14	  d = d + d2 + 20;
(gdb) stepi
14	  d = d + d2 + 20;
(gdb) stepi
0x0000000120000768	14	  d = d + d2 + 20;
(gdb) stepi
15	  return d;
(gdb) stepi
16	}
(gdb) next
main () at test.c:25
25	   b = a + b; 
(gdb) next
26	   return 1; 
(gdb) next
27	}

可以看到stepi也是逐条指令执行，会进入到函数add和add1内部执行，符合预期
posted on 2023-10-10 10:16 lh03061238 阅读(141) 评论(0) 收藏举报
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