Using GCC to produce readable assembly?

2018-07-01 02:50:29

I was wondering how to use GCC on my C source file to dump a mnemonic version of the machine code so I could see what my code was being compiled into. You can do this with Java but I haven't been able to find a way with GCC.

I am trying to re-write a C method in assembly and seeing how GCC does it would be a big help.

If you compile with debug symbols, you can use objdump to produce a more readable disassembly.

>objdump --help
[...]
-S, --source             Intermix source code with disassembly
-l, --line-numbers       Include line numbers and filenames in output

Example:

> gcc -g -c test.c
> objdump -d -M intel -S test.o

test.o:     file format elf32-i386


Disassembly of section .text:

00000000 <main>:
#include <stdio.h>

int main(void)
{
   0:   55                      push   ebp
   1:   89 e5                   mov    ebp,esp
   3:   83 e4 f0                and    esp,0xfffffff0
   6:   83 ec 10                sub    esp,0x10
    puts("test");
   9:   c7 04 24 00 00 00 00    mov    DWORD PTR [esp],0x0
  10:   e8 fc ff ff ff          call   11 <main+0x11>

    return 0;
  15:   b8 00 00 00 00          mov    eax,0x0
}
  1a:   c9                      leave  
  1b:   c3                      ret

我想补充一下这些答案，如果你给gcc flag -fverbose-asm ，它发出的汇编器会更清晰地阅读。

Use the -S (note: capital S) switch to GCC, and it will emit the assembly code to a file with a .s extension. For example, the following command:

gcc -O2 -S foo.c

will leave the generated assembly code on the file foo.s.

Ripped straight from http://www.delorie.com/djgpp/v2faq/faq8_20.html (but removing erroneous -c )

链接地址: http://www.djcxy.com/p/86790.html

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