如何查看.o和.exe文件

生成目标文件

1. test.cpp如下所示：

#include <iostream>

using namespace std;
int ga;
int gb = 100;
int main()
{
    static int sa;
    static int sb = 200;
    int aa;
    int ab = 300;
    return 0;
}

2. 使用如下命令生成test.o文件

g++  test.cpp -o test.o

查看目标文件

1. 查看的基础知识：.rodata表示只读数据段，.comment表示注释信息段，每个段的第二行中的CONTENTS，ALLOC等表示段的各种属性。CONTENTS表示该段在文件中存在。LMA表示load memory address，即加载地址，VMA表示virtual memory address，即虚拟地址

// 可以查看该目标文件的信息
objdump -h test.o

test.o:     file format elf64-x86-64

Sections:
Idx Name          Size      VMA               LMA               File off  Algn
  0 .text         0000007c  0000000000000000  0000000000000000  00000040  2**0
                  CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
  1 .data         00000008  0000000000000000  0000000000000000  000000bc  2**2
                  CONTENTS, ALLOC, LOAD, DATA
  2 .bss          0000000c  0000000000000000  0000000000000000  000000c4  2**2
                  ALLOC
  3 .rodata       00000001  0000000000000000  0000000000000000  000000c4  2**0
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  4 .init_array   00000008  0000000000000000  0000000000000000  000000c8  2**3
                  CONTENTS, ALLOC, LOAD, RELOC, DATA
  5 .comment      0000002b  0000000000000000  0000000000000000  000000d0  2**0
                  CONTENTS, READONLY
  6 .note.GNU-stack 00000000  0000000000000000  0000000000000000  000000fb  2**0
                  CONTENTS, READONLY
  7 .note.gnu.property 00000020  0000000000000000  0000000000000000  00000100  2**3
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  8 .eh_frame     00000078  0000000000000000  0000000000000000  00000120  2**3
                  CONTENTS, ALLOC, LOAD, RELOC, READONLY, DATA

查看.exe文件

// 查看.exe文件
objdump -h test

test:     file format elf64-x86-64

Sections:
Idx Name          Size      VMA               LMA               File off  Algn
  0 .interp       0000001c  0000000000000318  0000000000000318  00000318  2**0
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  1 .note.gnu.property 00000020  0000000000000338  0000000000000338  00000338  2**3
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  2 .note.gnu.build-id 00000024  0000000000000358  0000000000000358  00000358  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  3 .note.ABI-tag 00000020  000000000000037c  000000000000037c  0000037c  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  4 .gnu.hash     00000024  00000000000003a0  00000000000003a0  000003a0  2**3
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  5 .dynsym       000000d8  00000000000003c8  00000000000003c8  000003c8  2**3
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  6 .dynstr       000000d5  00000000000004a0  00000000000004a0  000004a0  2**0
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  7 .gnu.version  00000012  0000000000000576  0000000000000576  00000576  2**1
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  8 .gnu.version_r 00000040  0000000000000588  0000000000000588  00000588  2**3
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  9 .rela.dyn     000000f0  00000000000005c8  00000000000005c8  000005c8  2**3
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
 10 .rela.plt     00000030  00000000000006b8  00000000000006b8  000006b8  2**3
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
 11 .init         0000001b  0000000000001000  0000000000001000  00001000  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, CODE
 12 .plt          00000030  0000000000001020  0000000000001020  00001020  2**4
                  CONTENTS, ALLOC, LOAD, READONLY, CODE
 13 .plt.got      00000010  0000000000001050  0000000000001050  00001050  2**4
                  CONTENTS, ALLOC, LOAD, READONLY, CODE
 14 .plt.sec      00000020  0000000000001060  0000000000001060  00001060  2**4
                  CONTENTS, ALLOC, LOAD, READONLY, CODE
 15 .text         000001e5  0000000000001080  0000000000001080  00001080  2**4
                  CONTENTS, ALLOC, LOAD, READONLY, CODE
 16 .fini         0000000d  0000000000001268  0000000000001268  00001268  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, CODE
 17 .rodata       00000005  0000000000002000  0000000000002000  00002000  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
 18 .eh_frame_hdr 00000054  0000000000002008  0000000000002008  00002008  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
 19 .eh_frame     00000148  0000000000002060  0000000000002060  00002060  2**3
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
 20 .init_array   00000010  0000000000003d90  0000000000003d90  00002d90  2**3
                  CONTENTS, ALLOC, LOAD, DATA
 21 .fini_array   00000008  0000000000003da0  0000000000003da0  00002da0  2**3
                  CONTENTS, ALLOC, LOAD, DATA
 22 .dynamic      00000200  0000000000003da8  0000000000003da8  00002da8  2**3
                  CONTENTS, ALLOC, LOAD, DATA
 23 .got          00000058  0000000000003fa8  0000000000003fa8  00002fa8  2**3
                  CONTENTS, ALLOC, LOAD, DATA
 24 .data         00000018  0000000000004000  0000000000004000  00003000  2**3
                  CONTENTS, ALLOC, LOAD, DATA
 25 .bss          00000010  0000000000004018  0000000000004018  00003018  2**2
                  ALLOC
 26 .comment      0000002a  0000000000000000  0000000000000000  00003018  2**0
                  CONTENTS, READONLY

查看ELF文件中的代码段和数据段，BSS段的长度

size test.o

1.代码段

// -s参数将各个段的内容以十六进制的方式打印
// -d将包含指令的段反汇编
objdump -s -d test.o

.text 000001e5 0000000000001080 0000000000001080 00001080 24
CONTENTS, ALLOC, LOAD, READONLY, CODE
.text 000001e5 0000000000001080 0000000000001080 00001080 24
CONTENTS, ALLOC, LOAD, READONLY, CODE