C言語でのreturnは他動詞ではなく自動詞

        // Function with return value.
int add3(int x) {
    return x + 3;  // (1)
}

// Function without return value.
void do_nothing(void) {
    // Return explicitly.
    return;  // (2)
}
      

        $ uname -a
Linux veg 4.6.3-gentoo #1 SMP PREEMPT Sun Jul 3 10:47:16 JST 2016 x86_64 Intel(R) Core(TM) i7-4500U CPU @ 1.80GHz GenuineIntel GNU/Linux
$ gcc --version
gcc (Gentoo 5.4.0 p1.0, pie-0.6.5) 5.4.0
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ gcc -O0 -c test.c
$ objdump -d -M intel test.o >test.c-objdump

      

        test.o:     ファイル形式 elf64-x86-64


セクション .text の逆アセンブル:

0000000000000000 <add3>:
   0: 55                    push   rbp
   1: 48 89 e5              mov    rbp,rsp
   4: 89 7d fc              mov    DWORD PTR [rbp-0x4],edi
   7: 8b 45 fc              mov    eax,DWORD PTR [rbp-0x4]
   a: 83 c0 03              add    eax,0x3
   d: 5d                    pop    rbp
   e: c3                    ret    

000000000000000f <do_nothing>:
   f: 55                    push   rbp
  10: 48 89 e5              mov    rbp,rsp
  13: 90                    nop
  14: 5d                    pop    rbp
  15: c3                    ret
      

        // Get the 1st argument.
EAX = *((DWORD *)(rbp-0x4));  // mov    eax,DWORD PTR [rbp-0x4]
// Add 3.
EAX += 3;  // add    eax,0x3
// Return.
return;  // ret
      

        // Do nothing.
;  // nop
// Return.
return;  // ret