assembly – 链接汇编程序:错误“未定义引用`printf’”

我正在尝试在x64 Debian上编译这个x86 assembly code

BITS 32

%include    'training.s' 

global main
extern  exit    

; ===============================================
section .text

main:
    ; The program begins here:

    call    read_hex    
    mov     edx,eax
    call    read_hex    
    add     eax,edx
    add     eax,eax
    inc     eax         

    call    print_eax   

    ; Exit the process:
    push    0
    call    exit

我收到这些错误:

~$nasm -f elf -g 0_strange_calc.asm && ld -o 0_strange_calc 0_strange_calc.o
    ld: i386 architecture of input file `0_strange_calc.o' is incompatible with i386:x86-64 output
    ld: warning: cannot find entry symbol _start; defaulting to 00000000004000b0
    0_strange_calc.o:training.s:25: undefined reference to `printf'
    0_strange_calc.o:training.s:35: undefined reference to `printf'
    0_strange_calc.o:training.s:45: undefined reference to `printf'
    0_strange_calc.o:training.s:56: undefined reference to `read'
    0_strange_calc.o:training.s:77: undefined reference to `scanf'
    0_strange_calc.o:training.s:97: undefined reference to `scanf'
    0_strange_calc.o:training.s:108: undefined reference to `printf'
    0_strange_calc.o:training.s:129: undefined reference to `printf'
    0_strange_calc.o:training.s:137: undefined reference to `printf'
    0_strange_calc.o:0_strange_calc.asm:50: undefined reference to `exit'




 ~$yasm -f elf64 0_strange_calc.asm
    ~$gcc -m32 -nostdlib -nostdinc 0_strange_calc.o -o 0_strange_calc
    /usr/bin/ld: i386:x86-64 architecture of input file `0_strange_calc.o' is incompatible with i386 output
    /usr/bin/ld: warning: cannot find entry symbol _start; defaulting to 00000000080480c0
    0_strange_calc.o: In function `no symbol':
    0_strange_calc.asm:(.text+0x8): undefined reference to `printf'
    0_strange_calc.asm:(.text+0x19): undefined reference to `printf'
    0_strange_calc.asm:(.text+0x2a): undefined reference to `printf'
    0_strange_calc.asm:(.text+0x39): undefined reference to `read'
    0_strange_calc.asm:(.text+0x5b): undefined reference to `scanf'
    0_strange_calc.asm:(.text+0x7a): undefined reference to `scanf'
    0_strange_calc.asm:(.text+0x89): undefined reference to `printf'
    0_strange_calc.asm:(.text+0xa8): undefined reference to `printf'
    0_strange_calc.asm:(.text+0xb9): undefined reference to `printf'
    0_strange_calc.o: In function `main':
    0_strange_calc.asm:(.text+0xdb): undefined reference to `exit'
    collect2: error: ld returned 1 exit status

这是我的0_strange_calc.o转储:

~$objdump -M intel -d 0_strange_calc.o

0_strange_calc.o:     file format elf64-x86-64


Disassembly of section .text:

0000000000000000 <main-0xc2>:
   0:   60                      (bad)  
   1:   50                      push   rax
   2:   68 00 00 00 00          push   0x0
   7:   e8 00 00 00 00          call   c <main-0xb6>
   c:   83 c4 08                add    esp,0x8
   f:   61                      (bad)  
  10:   c3                      ret    
  11:   60                      (bad)  
  12:   50                      push   rax
  13:   68 00 00 00 00          push   0x0
  18:   e8 00 00 00 00          call   1d <main-0xa5>
  1d:   83 c4 08                add    esp,0x8
  20:   61                      (bad)  
  21:   c3                      ret    
  22:   60                      (bad)  
  23:   b8 00 00 00 00          mov    eax,0x0
  28:   50                      push   rax
  29:   e8 00 00 00 00          call   2e <main-0x94>
  2e:   83 c4 04                add    esp,0x4
  31:   61                      (bad)  
  32:   c3                      ret    
  33:   60                      (bad)  
  34:   51                      push   rcx
  35:   57                      push   rdi
  36:   6a 00                   push   0x0
  38:   e8 00 00 00 00          call   3d <main-0x85>
  3d:   83 c4 0c                add    esp,0xc
  40:   31 d2                   xor    edx,edx
  42:   c6 04 07 00             mov    BYTE PTR [rdi+rax*1],0x0
  46:   61                      (bad)  
  47:   c3                      ret    
  48:   55                      push   rbp
  49:   89 e5                   mov    ebp,esp
  4b:   83 ec 04                sub    esp,0x4
  4e:   53                      push   rbx
  4f:   51                      push   rcx
  50:   52                      push   rdx
  51:   8d 5d fc                lea    ebx,[rbp-0x4]
  54:   53                      push   rbx
  55:   68 00 00 00 00          push   0x0
  5a:   e8 00 00 00 00          call   5f <main-0x63>
  5f:   83 c4 08                add    esp,0x8
  62:   8b 03                   mov    eax,DWORD PTR [rbx]
  64:   5a                      pop    rdx
  65:   59                      pop    rcx
  66:   5b                      pop    rbx
  67:   c9                      leave  
  68:   c3                      ret    
  69:   55                      push   rbp
  6a:   89 e5                   mov    ebp,esp
  6c:   83 ec 04                sub    esp,0x4
  6f:   8d 5d fc                lea    ebx,[rbp-0x4]
  72:   60                      (bad)  
  73:   53                      push   rbx
  74:   68 00 00 00 00          push   0x0
  79:   e8 00 00 00 00          call   7e <main-0x44>
  7e:   83 c4 08                add    esp,0x8
  81:   61                      (bad)  
  82:   8b 03                   mov    eax,DWORD PTR [rbx]
  84:   c9                      leave  
  85:   c3                      ret    
  86:   60                      (bad)  
  87:   56                      push   rsi
  88:   e8 00 00 00 00          call   8d <main-0x35>
  8d:   83 c4 04                add    esp,0x4
  90:   61                      (bad)  
  91:   c3                      ret    
  92:   60                      (bad)  
  93:   b9 20 00 00 00          mov    ecx,0x20
  98:   d1 c0                   rol    eax,1
  9a:   89 c2                   mov    edx,eax
  9c:   83 e2 01                and    edx,0x1
  9f:   51                      push   rcx
  a0:   50                      push   rax
  a1:   52                      push   rdx
  a2:   68 00 00 00 00          push   0x0
  a7:   e8 00 00 00 00          call   ac <main-0x16>
  ac:   83 c4 08                add    esp,0x8
  af:   58                      pop    rax
  b0:   59                      pop    rcx
  b1:   e2 e5                   loop   98 <main-0x2a>
  b3:   68 00 00 00 00          push   0x0
  b8:   e8 00 00 00 00          call   bd <main-0x5>
  bd:   83 c4 04                add    esp,0x4
  c0:   61                      (bad)  
  c1:   c3                      ret    

00000000000000c2 <main>:
  c2:   e8 81 ff ff ff          call   48 <main-0x7a>
  c7:   89 c2                   mov    edx,eax
  c9:   e8 7a ff ff ff          call   48 <main-0x7a>
  ce:   01 d0                   add    eax,edx
  d0:   01 c0                   add    eax,eax
  d2:   40 e8 28 ff ff ff       rex call 0 <main-0xc2>
  d8:   6a 00                   push   0x0
  da:   e8 00 00 00 00          call   df <main+0x1d>

它似乎已经在x64 asm中成功转换,我编译和链接的其他简单代码没有问题.我究竟做错了什么?我该如何解决?

最佳答案
你有几个选择

>使用LD链接到最终的可执行文件
>使用GCC链接到最终的可执行文件

使用LD方法

您的命令行使用LD,遗憾的是,这会产生许多问题.首先:

ld: i386 architecture of input file `0_strange_calc.o’ is incompatible with i386:x86-6

您使用64位Debian,尝试生成32位可执行文件. -f elf在NASM命令行上生成32位ELF(-f elf64生成64位对象).默认情况下,LD命令行尝试生成64位可执行文件,因此会给出上面的错误.您可以通过在LD的命令行中添加-m elf_i386选项来强制LD生成32位可执行文件.

ld: warning: cannot find entry symbol _start; defaulting to 00000000004000b0

你应该告诉LD你的入口点是主要的.默认情况下,LD会查找_start的入口点.您可以将-e main添加到LD命令行以解决该问题.

像这样的错误表明你需要C库(printf存在的地方):

0_strange_calc.asm:(.text+0x8): undefined reference to `printf’

由于您的代码不直接使用printf,我只能假设training.s中的函数需要它.要在C库中进行链接,您需要在命令行中的.o文件之后添加它.您可以在LD命令行上使用-lc执行此操作.您还需要告诉LD具体需要使用的动态链接库(在本例中为32位).在Debian环境中,通常如下所示:-dynamic-linker /lib/ld-linux.so.2

所以你的NASM和LD线应该是这样的:

nasm -f elf -g 0_strange_calc.asm
ld -melf_i386 -e main -dynamic-linker /lib/ld-linux.so.2 -o 0_strange_calc  0_strange_calc.o -lc

使用GCC方法

您可以使用GCC将目标文件链接到可执行文件,从而简化与C库的链接.要构建32位可执行文件,您可以使用:

nasm -f elf -g 0_strange_calc.asm
gcc -m32 0_strange_calc.o -o 0_strange_calc

C库和运行时有一个_start方法,它执行C启动初始化,然后调用一个名为main的函数,该函数恰好是汇编文件中的函数. -m32告诉GCC你也链接到32位可执行文件.

特别注意事项

您可能还需要安装gl的Multlilib版本(如果需要,还可以安装g),这样您就可以使用适当的C库在64位Debian上正确构建和运行32位应用程序.这可以使用此命令行完成:

apt-get install gcc-multilib g++-multilib

在基于Ubuntu的系统上,您需要使用:

sudo apt-get install gcc-multilib g++-multilib

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