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Question

that looks like this:

Is it possible that I can get an output like this: (abbr)

int factorial(int n) {
  int result = 1;
  for (int i = 1; i <= n; ++i) {
    result *= i;
  }
  return result;
}

int main() {
  factorial(10);
}

i.e. without machine code. I looked at the man page, and couldn't find an option like that.

Is there another tool which can show me the assembly intermingled with the source code? I know that many IDEs like visual studio has this feature built in.

Btw, one way is using

and then call main.o and that produces what I need, but it is too much work to start gdb and run that command.

I have a simple cpp program in main.cpp: int factorial(int n) { int result = 1; for (int i = 1; i <= n; ++i) { result *= i; } return result; } int main() { factorial(10); } One can ...

0000000000000000 <_Z9factoriali>:
int factorial(int n) {
   0:   55                      push   rbp
   1:   48 89 e5                mov    rbp,rsp
   4:   89 7d ec                mov    DWORD PTR [rbp-0x14],edi
  int result = 1;
   7:   c7 45 fc 01 00 00 00    mov    DWORD PTR [rbp-0x4],0x1
  for (int i = 1; i <= n; ++i) {
   e:   c7 45 f8 01 00 00 00    mov    DWORD PTR [rbp-0x8],0x1
  15:   8b 45 f8                mov    eax,DWORD PTR [rbp-0x8]
  18:   3b 45 ec                cmp    eax,DWORD PTR [rbp-0x14]
  1b:   7f 0f                   jg     2c <_Z9factoriali+0x2c>
    result *= i;
  1d:   8b 45 fc                mov    eax,DWORD PTR [rbp-0x4]
  20:   0f af 45 f8             imul   eax,DWORD PTR [rbp-0x8]
  24:   89 45 fc                mov    DWORD PTR [rbp-0x4],eax
  for (int i = 1; i <= n; ++i) {
  27:   ff 45 f8                inc    DWORD PTR [rbp-0x8]
  2a:   eb e9                   jmp    15 <_Z9factoriali+0x15>
  }
  return result;
  2c:   8b 45 fc                mov    eax,DWORD PTR [rbp-0x4]
}
  2f:   5d                      pop    rbp
  30:   c3                      ret 

From manpage of objdump,

0000000000000000 <_Z9factoriali>:
int factorial(int n) {
   push   rbp                   
   mov    rbp,rsp               
   mov    DWORD PTR [rbp-0x14],edi
  int result = 1;
   mov    DWORD PTR [rbp-0x4],0x1
  for (int i = 1; i <= n; ++i) {
   mov    DWORD PTR [rbp-0x8],0x1
   mov    eax,DWORD PTR [rbp-0x8]
   cmp    eax,DWORD PTR [rbp-0x14]
   jg     2c <_Z9factoriali+0x2c>
  result *= i;
   mov    eax,DWORD PTR [rbp-0x4]
   imul   eax,DWORD PTR [rbp-0x8]
   mov    DWORD PTR [rbp-0x4],eax
  for (int i = 1; i <= n; ++i) {
   inc    DWORD PTR [rbp-0x8]
   jmp    15 <_Z9factoriali+0x15>
  }
  return result;
   mov    eax,DWORD PTR [rbp-0x4]
}
  pop    rbp                    
  ret  

--no-show-raw-insn When disassembling instructions, do not print the instruction bytes. This is the default when --prefix-addresses is used.

So, gdb should do the trick.disassemble /m func_name

我有一个简单的cpp程序main.cpp。

Answer 1

g++ -c -g main.cpp

然后我们可以在此基础上运行 objdump

来查看汇编代码和机器代码以及源代码。

objdump -S -M intel --no-show-raw-insn main.o | lessobjdump -S -M intel main.o。